Virtual Library

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    MS03 - The Cutting Edge of Molecularly Targeted Therapy (ID 20)

    • Event: WCLC 2013
    • Type: Mini Symposia
    • Track: Medical Oncology
    • Presentations: 4
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      MS03.1 - Novel Targets in Small Cell Cancer (ID 467)

      R. Thomas

      • Abstract
      • Presentation
      • Slides

      Abstract
      I will discuss recent results from genomic sequencing studies on small cell lung cancer. In particular, results related to possible therapeutic opportunities will be a focus of my talk.

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      MS03.2 - Novel Targets in Squamous Cancer (ID 468)

      P. Hammerman

      • Abstract
      • Presentation
      • Slides

      Abstract
      Lung squamous cell carcinoma (lung SqCC) is the second most common histology of non-small cell lung cancer (NSCLC). While the treatment of lung adenocarcinoma has developed substantially over the past decade due to the discovery of a host of therapeutic biomarkers progress in lung SqCC has been more modest. However, large scale genomic studies of lung SqCC as well as early biomarker directed trials suggest that treatment options are likely to improve in the near future for lung SqCC given the rapid expansion in our knowledge of the molecular basis of this disease. There is now an opportunity for substantial improvement in outcomes for patients with lung SqCC and my presentation will focus on the opportunities and challenges that face our community as we try to make progress in treating this disease. Here, I will discuss several recent studies which have defined the genomic landscape of lung SqCC in multiple patient cohorts and discuss the results of these studies in contrast to lung adenocarcinoma. I will review the predictive and prognostic biomarkers identified to date for lung SqCC and present pre-clinical and early clinical data on several therapeutic biomarkers with an emphasis on Fibroblast Growth Factor Receptor alterations. I will note clinical trials in progress and those which are likely to begin soon as well as diagnostic testing for patients with lung SqCC. I will also discuss pre-clinical data which have shed light on the development of lung SqCCs and discuss opportunities for further development in this field.

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      MS03.3 - Novel Targets in Adenocarcinoma (ID 469)

      M. Meyerson

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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    MS04 - Mesothelioma Genetics and Novel Targets (ID 21)

    • Event: WCLC 2013
    • Type: Mini Symposia
    • Track: Mesothelioma
    • Presentations: 5
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      MS04.0 - N/A - Chair Intro (ID 470)

      • Abstract

      Abstract not provided

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      MS04.1 - BAP1 Gene Mutation and Mesothelioma Pathogenesis (ID 471)

      A. Napolitano, M. Carbone

      • Abstract
      • Presentation
      • Slides

      Abstract
      Malignant mesothelioma (MM) is a lethal cancer whose pathogenesis results from complex interactions between host genetics and environmental carcinogens, such as asbestos and erionite fibers. Recently, BAP1 (BRCA associated protein 1) has been identified as a novel MM tumor suppressor gene. BAP1 is located at the 3p21, a region frequently deleted in MM, and encodes for a deubiquitinase enzyme known to target histones and other proteins. Originally discovered as a BRCA1 interacting protein, BAP1 appears to exert its anti-tumor activities mainly in a BRCA-independent manner, through its association in multi-protein complexes with diverse functions. For example, when associated to the Polycomb protein ASXL1, BAP1 is important for the regulation of the cell epigenome, via modulation of histone H2A ubiquitination and thus chromatin accessibility. In complex with other proteins (e.g. HCF-1, OGT, and YY1), BAP1 is also important in the transcriptional regulation of several genes and in the stability of target proteins such as PGC-1α. Recent reports also suggest a possible involvement of BAP1 in DNA repair pathways. However, the relevance of BAP1 to the biology of normal and cancer cells remains largely unexplained, in fact manipulation of BAP1 in cancer cells has often yielded unexpected or even contradictory results. For example, silencing of BAP1 in MM and uveal melanoma cell lines resulted in reduced cell growth (Bott et al; Matatall et al). We discovered that germline BAP1 mutations cause a novel cancer syndrome characterized by a significant excess of both pleural and peritoneal MM, uveal and cutaneous melanoma and possibly other tumors. In the same study, we reported that 22% sporadic MM tumors harbored somatic BAP1 mutations (Testa et al). In a separate study using 53 primary pleural MM collected in the USA, 42% of tumors harbored either BAP1 loss, BAP1 somatic mutations (detected in 23% of the samples), or both. Moreover, another 25% of tumors showed no BAP1 staining by immunohistochemistry (IHC) despite apparently normal BAP1 status, raising the possibility of post-translational deregulation of BAP1 in a subset of cases. In this MM cohort, there was a significant association between BAP1 status and patients’ age (66.7 years in mutant BAP1 compared to 58.6 years in wild-type BAP1), but there was no significant correlation with other variables such as sex, overall survival, histological subtype or asbestos exposure (Bott et al). In a recent meeting, using a bigger sample size, the same group confirmed that somatic BAP1 mutations occur in about 20% of pleural MM. They reported that the only clinical variable significantly different among those with and without BAP1 mutations was smoking (former or current), with BAP1 mutations more prevalent among smokers (75% vs. 42%). A Japanese study reported BAP1 gene alterations (either deletions or sequence-level mutations) in 61% of their 23 MM samples (Yoshikawa et al). Their data, but not those reported by Bott et al, also suggested an association between BAP1 mutations and the epithelioid histological MM subtype. Whether this discrepancy results from the different methodologies in sample preparation and detection of BAP1 mutations or it is an intrinsic difference between the two populations (e.g. due to ethnicity) has still to be determined. A third recent study, with a separate cohort of 52 pleural MM, reported absence of BAP1 IHC staining in 60% of pleural MM, confirming previous results (Arzt et al). The Authors also confirmed the absence of a correlation between BAP1 expression and asbestos exposure, and suggested that expression of BAP1 in tumor samples is inversely correlated to survival. The discovery of BAP1 germline and somatic mutations has renewed after decades the interest in MM genetics. Because germline BAP1 mutations predispose to multiple cancers and because BAP1 loss of heterozygosity is frequent in different tumor types, BAP1 would appear to act as a classical tumor suppressor. However, this definition is unsatisfactory because manipulation in vitro of BAP1 expression has often given unexpected and paradoxical results, complicating our understanding of its mechanisms of action. BAP1 absence (due to genetic, genomic, epigenomic or post-translational causes) was reported in about 60% of pleural MM. No studies so far have thoroughly investigated BAP1 expression in MMs arising from other sites. BAP1 expression is not associated to asbestos exposure, suggesting that its role in MM pathogenesis may be independent from the known asbestos-related pathways. Other clinicopathological associations are at this moment too weak to be conclusive, possibly due to limited tumor sample sizes, methodological differences in the studies or finally ethical differences of the analyzed populations. It appears, but remains unproven, that patients with germline BAP1 mutations have less aggressive MMs compared to sporadic MMs in which BAP1 mutations do not appear to influence prognosis. More experiments are urgently required to see whether BAP1 expression could be use in diagnostic, prognostic, or therapeutic settings. In fact, defining a therapeutically accessible synthetic lethal target in the setting of BAP1 loss could eventually benefit the approximately 40-60% of patients with BAP1 negative MMs. Even more speculatively, the same synthetic lethal target could be studied as chemoprevention drug targets in individuals with germline BAP1 mutations. The impact of this work obviously extends to other cancers with BAP1 mutations.

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      MS04.2 - Sequencing the Mesothelioma Genome - Where Are We Now and Where Are We Going? (ID 472)

      R. Bueno

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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      MS04.3 - New Molecular Targets in Mesothelioma (ID 473)

      R. Stahel

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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      MS04.4 - Current Clinical Trials of Targeted Therapies (ID 474)

      P. Baas

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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    MINI 21 - Novel Targets (ID 133)

    • Event: WCLC 2015
    • Type: Mini Oral
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 13
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      MINI21.01 - Purinergic Signaling in NSCLC - First in Vivo Data and Potential Therapeutic Targets (ID 166)

      S. Schmid, K. Ayata, Z. Lazar, M. Kübler, M. Elze, B. Haager, B. Passlick, M. Idzko

      • Abstract
      • Presentation
      • Slides

      Background:
      Purines are well known as intracellular sources for energy but also act as extracellular signaling molecules. In the last decade there has been a growing interest in the therapeutic potential of purinergic signaling for cancer treatment. The effects carried out depend on the concentration, expressed pattern of purinergic receptors and general dynamics of synthesis and degradation. In this study we analyze different purines and purinergic receptors in bronchoalveolar lavage (BAL) of patients with non-small-cell lung cancer (NSCLC) to provide further insight on their relevance in the tumor microenvironment.

      Methods:
      In this prospective clinical trial we enrolled 27 patients with NSCLC and 16 patients with chronic obstructive pulmonary disease (COPD) without signs of malignancy. The study was approved by our local ethics committee and registered as a clinical trial in the German Registry for Clinical Trials (DRKS-ID: DRKS00005415). BAL was performed using flexible bronchoscopes. The bronchoscope was wedged into a subsegment were the tumor was present and a total of 300 ml sterile saline was instilled. The BAL-fluid (BALF) was recovered by gentle aspiration. Purines (ATP, ADP, AMP, Adenosine and Inosine) were analyzed using fluorescence/luminescence based assays. Expression of purinergic receptors and Ectonucleotidases in NSCLC (P2X1, P2X4, P2X7, P2Y1, P2Y2, P2Y4, P2Y6, P2Y12, P2Y13, P2Y14, CD39, CD73) were analyzed using qPCR.

      Results:
      Patients with NSCLC have significantly lower ATP and ADP concentrations in BALF than patients with COPD without signs of malignancy (p=0.006 and p=0.009). Inosine concentrations however are higher in patients with malignant disease (p=0.01). In the subgroup-analysis of metastasized versus non-metastasized tumors receptor-analysis revealed a higher expression of P2X4 (p=0.07), P2X7 (p=0.0008) and P2Y1 (p=0.009) as well as of the ectonucleotidase CD39 (p=0.007). Analysis of the purine metabolites in the respective groups showed no statistically significant differences. Furthermore there is a positive correlation of the proportion of macrophages in differential cell count in BAL with the expression of P2X7 (r=0.53, p=0.02).

      Conclusion:
      Previous data suggests pro-inflammatory, zytotoxic and thus anti-neoplastic effects of Adenosine-Triphosphate (ATP) and ADP. Also it has been shown that low ATP concentrations in the tumor microenvironment can lead to enhanced proliferation of tumor cells. In this first in vivo study on purinergic signaling in lung cancer we find lower concentrations of ATP and ADP in samples from NSCLC patients compared to COPD without signs of malignancy in accordance with these findings. Furthermore in aggressive, metastasized NSCLC we find a higher expression of the ectonucleotidase CD39. This enzyme degrades ATP and ADP to Adenosin and has previously been shown to hence induce immune escape in malignant disease. Furthermore we demonstrate elevated expression of P2X4, P2X7 and P2Y1 in the tumor microenvironment of metastasized NSCLC compared to non-metastasized tumors. This suggests a role of these receptors in tumor metastasis, however the exact mechanisms remain unclear. To further illustrate these interactions we are currently initiating a study to identify purinergic receptors in NSCLC tumor cells from pathologic specimen. With this knowledge future translational studies can be conducted to potentially provide new therapeutic targets.

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      MINI21.02 - CCT68127 Is a Next Generation CDK2/9 Inhibitor with Potent Antineoplastic Activity Against Lung Cancer Cells (ID 554)

      M. Kawakami, L.M. Mustachio, X. Liu, S. Hu, Y. Lu, D. Sekula, S. Freemantle, E. Dmitrovsky

      • Abstract
      • Presentation
      • Slides

      Background:
      Lung cancer growth was significantly repressed by the first generation CDK2/9/7 inhibitor seliciclib (R-roscovitine, CYC202, Cyclacel Ltd). This induced anaphase catastrophe and apoptosis to occur. Anaphase catastrophe happens when supernumerary centrosomes attempt mitosis by clustering extra centrosomes. If this clustering is inhibited, cells segregate chromosomes inappropriately and anaphase catastrophe occurs and leads to death of daughter cells. This study explored antineoplastic effects of a next generation CDK2/9 inhibitor: CCT68127 (Cyclacel) against lung cancer cells. CCT68127 inhibits CDK2/9 more potently and selectively than seliciclib (IC50s for CDK2 and CDK9 are 30nM and 110nM, respectively).

      Methods:
      Antineoplastic CCT68127 effects in murine (transgenic mouse-derived) and human lung cancer cells were compared to seliciclib using luminescent cell viability assays. Cell cycle arrest and apoptosis induction by CCT68127 were detected using fluorescence-based cell imaging after staining with propidium iodide (PI) and double-staining with Annexin V and PI. Multipolar anaphase cells were scored after a tubulin and DNA staining. RPPA (Reverse Phase Protein Assay) analyses were performed in CCT68127 and vehicle-treated lung cancer cells to uncover mechanisms engaged by CDK2/9 antagonism. Expression levels of nearly 200 key growth-regulatory proteins were examined before and after 6, 24, and 48 hours of CCT68127 versus vehicle treatments of murine: ED1 (wild-type KRAS) and LKR13 (mutant KRAS) and human lung cancer cells: H522 (wild-type KRAS) and Hop62 (mutant KRAS).

      Results:
      IC50s of CCT68127 in murine lung cancer cells (ED1, LKR13, and 393P) were <1µM while IC50 of seliciclib was >25µM. KRAS mutant murine lung cancer cells (LKR13 and 393P) were more sensitive to CCT68127 than the KRAS wild-type line (ED1). In contrast, growth inhibition in C10 immortalized murine pulmonary epithelial cells was negligible. IC50s in human lung cancer cell lines (Hop62, A549, H2122, H522, and H1703) were comparable to murine lung cancer cell lines. KRAS mutant lung cancer cells (Hop62, A549, and H2122) were more sensitive than KRAS wild-type lung cancer cell lines (H522 and H1703). Immortalized human bronchial epithelial cells (BEAS-2B) were resistant to CCT68127 treatment. CCT68127 triggered apoptosis in a dose-dependent manner in murine lung cancer cell lines and at much lower concentrations than seliciclib. CCT68127 caused G1 arrest. Its growth inhibition was partially reversed in washout experiments. CCT68127 also induced apoptosis in human lung cancer cells (Hop62, A549, H522, and H1703). A mechanism responsible for these effects was found. Anaphase catastrophe was triggered by CCT68127 treatment of murine and human lung cancer cell lines and was independent of KRAS mutation status. RPPA analyses uncovered distinct protein profiles after CCT68127 treatment. These included DNA repair, Hippo and Rab GTPase pathway members that were each markedly down-regulated.

      Conclusion:
      CCT68127 is a next generation CDK2/9 inhibitor that has more potent antineoplastic activity against KRAS mutant and wild-type lung cancer cells than the prior inhibitor, seliciclib. This occurred via induced anaphase catastrophe and was linked to changes in expressed growth regulatory proteins. Taken together, these findings implicate use of a next generation CDK2/9 inhibitor for human lung cancer cases.

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      MINI21.03 - CACNA2D1 Is a Novel Biomarker for Tumor Initiating Cells and Has Therapeutic Effect in Non-Small Cell Lung Cancer (ID 3074)

      Y. Ma

      • Abstract
      • Presentation
      • Slides

      Background:
      Tumor initiating cells (TICs) are a small subpopulation within cancer that is thought to be resistant to conventional therapies and capable of reinitiating tumors. However, only a few biomarkers of TICs have been well elucidated.

      Methods:
      By the methods of QPCR, FACS, western blot, colony formation and statistic analysis, we have investigated whether CACNA2D1 (α2δ1) to enrich TICs of non-small cell lung cancer (NSCLC) and and tharget therapy of its antibody.

      Results:
      In comparison to α2δ1[-], α2δ1[+] cells demonstrated greater TICs properties with higher potential of self-renewal, differentiation and reconstituting tumors. Following treatment, these cells were enriched in clinical samples. We verified a monoclonal antibody of α2δ1 mAb which targets to α2δ1 had therapeutic treatment to TICs of NSCLC and further α2δ1 mAb combined with the common anti-cancer drug of carboplatin was obtained to suppress the established xenograft tumors. Importantly, the disease free survival and overall survival of NSCLC patients with increased α2δ1 expression was significantly shorter than that of patients with decreased expression. Mechanically, our results showed that a role of α2δ1 in up-regulating stemness of NSCLC cells was associated with NOTCH signaling.

      Conclusion:
      Collectively, our data indicate that α2δ1 could be used as a marker for identifying TICs of NSCLC and targeting these cells might provide a way to treat this disease.

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      MINI21.04 - HS3ST3B1 Is a Novel Regulator of TGF-Beta Mediated EMT and Regulated by miR-218 in Lung Cancer (ID 827)

      L. Miao, Y. Wang

      • Abstract
      • Presentation
      • Slides

      Background:
      Heparan sulfate D-glucosamine 3-O-sulfotransferase 3B1 (HS3ST3B1) participates in the biosynthetic steps of heparan sulfate (HS) and found to target VEGF in acute myeloid leukemia(AML) cells thus contributing the angiogenesis and proliferation of AML cells . However, the role of HS3ST3B1 in NSCLC has never been reported. In this study, we aim to investigate the role of HS3ST3B1 in NSCLC epithelial-to-mesenchymal transition.

      Methods:
      Expression of HS3ST3B1 was investigated by qRT-PCR in specimens of tumor and matched normal tissues of NSCLC patients and also in epithelial and mesenchymal NSCLC cell lines. A549 and HCC827 cell lines was induced to mesenchymal phenotype by TGF-β, and expression of HS3ST3B1, CDH1, and VIM were studied by PCR. HS3ST3B1 was knockdown by siRNA to analyze the effect of HS3ST3B1 on EMT. Computational predicting software was used to predict potential regulators of HS3ST3B1 and dual luciferase report system demonstrated that miR-218 may target HS3ST3B1 in cells. MiR-218 was tranfected into cells to analyze the association of miR-218 and HS3ST3B1 in cells.

      Results:
      HS3ST3B1 was significantly up-regulated in tumors compared with matched normal tissues(P=0.002). Its expression was also up-regulated in mesenchymal phenotype NSCLC cells lines compared with epithelial phenotype(P<0.05). When epithelial phenotype NSCLC cells transformed to mesenchymal phenotype induced by TGF-β, HS3ST3B1 was also significantly up-regulated. Moreover, when HS3ST3B1 was knockdown by siRNA in mesenchymal phenotype NSCLC cell lines, cells were reversed to epithelial phenotype morphologically. With Targetscan, we found that HS3ST3B1 was one potential targets of miR-218 and dual luciferase report system demonstrated that HS3ST3B1 was direct target of miR-218 in cells. When miR-218 was transfected into cells, we found that HS3ST3B1 was down-regulated. Figure 1 Figure 2





      Conclusion:
      HS3ST3B1 may regulate EMT and it can be regulated by miR-218 in NSCLC.

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      MINI21.05 - Discussant for MINI21.01, MINI21.02, MINI21.03, MINI21.04 (ID 3421)

      S. Popat

      • Abstract
      • Presentation

      Abstract not provided

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      MINI21.06 - Role of the Focal Adhesion Protein Paxillin in Lung Cancer - From Genetic Alterations to Novel Mitochondrial Functionality (ID 2188)

      R. Hasina, A. Rodriguez, S. Tumuluru, F. Lennon, Y.C. Tan, I. Kawada, R. Kanteti, R. Salgia

      • Abstract
      • Presentation
      • Slides

      Background:
      Cytoskeletal and focal adhesion abnormalities are observed in several types of cancer including lung cancer, which is attributed to a greater number of deaths than prostate, breast and colorectal cancers combined. Paxillin is a 68 kDa protein that is an integral part of the focal adhesion and acts as an adaptor molecule. We initially cloned the gene for paxillin, and localized it to chromosome 12q24. We have previously reported that paxillin can be mutated (approximately 8%), amplified (5-7%), and/or overexpressed in almost 80% of lung cancer patient samples. Paxillin protein is upregulated in more advanced stages of lung cancer compared with earlier stages and is a prognostic factor for non-small cell lung cancer (NSCLC). Paxillin gene is amplified in some pre-neoplastic lung lesions as well as neoplastic lesions. We identified 22 different variants of paxillin mutation in our initial investigation especially between the LD and the LIM domains (Jagadeeswaran et al. 2008). There are mutations that have been validated in the TCGA set. We selected six mutants to perform further studies ((P52L, A127T, P233L, T255I, D399N, and P487L as well as wild-type as control). Our investigations focused on an effort to understand the contribution of molecular abnormalities found in paxillin and their relationship to mitochondrial functionality.

      Methods:
      HEK293 cells as well as a paxillin null NSCLC cell line H522 was used to overexpress the above paxillin mutants and wild-type paxillin. Live cell confocal microscopy was performed to evaluate cell motility, immunoprecipitation to determine interaction with other proteins, and gene expression analysis was performed to evaluate effects on gene expression.

      Results:
      Among the mutations we investigated, we found that the most common paxillin mutant A127T in lung cancer cells enhanced cell proliferation, focal adhesion formation and co-localized with the anti-apoptotic protein B cell CLL/Lymphoma 2 (BCL-2), which among other sites also localizes to the mitochondria. We further found that when these variant clones of activating mutations were expressed in HEK293 cells, they conferred phenotypic changes resembling neoplastic cells. In gene chip microarrays assay investigating gene expression modulation conferred by these mutations in these same HEK293 cells, we found that P52L, A127T, T255I, P233L and D399N mutations, compared to wild-type paxillin, indeed modulated the expression of a significant number of genes. In particular, there were a number of mitochondrial signature proteins that were altered in the various mutants. Analyzing mitochondrial functions by measuring the interaction of these mutants with mitochondrial proteins MFN2, and DRP1, we identified that they alter mitochondrial dynamics, with significant fission rather than fusion. Paxillin also translocated from the focal adhesion to the mitochondrial membrane. In relationship to cisplatin responsiveness, PXN and mutant overexpression lead to cisplatin resistance.

      Conclusion:
      These data suggest that wild-type and mutant paxillin variants play a prominent role in neoplastic changes with direct implications in lung cancer progression and hence, its potential as a therapeutic target needs to be explored further.

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      MINI21.07 - Oncogenic EZH2 Is an Actionable Target in Patients with Adenocarcinoma of the Lung (LUAD) (ID 3169)

      B. Shi, C. Behrens, V. Vaghani, E. Riquelme, H. Lin, J.R. Canales, H. Lui, H. Kadara, I.I. Wistuba, G.R. Simon

      • Abstract
      • Presentation
      • Slides

      Background:
      The methyltransferase enhancer of zeste homolog 2 (EZH2) belongs to the polycomb repressive 2 complex (PRC2). EZH2 is upregulated in several malignancies including prostate, breast and lung cancer. The EZH2 protein forms one of the critical protein complexes of PRC2 by partnering with EED (embryonic ectoderm development) protein. This EED/EZH2 complex has been shown to interact with histone deacytelase (HDAC). This interaction is highly specific and HDAC does not interact with any other PRC2 protein complexes. In the present study, we investigated the link between EZH2 and HDAC in lung cancer cell lines and in human tumor tissue microarrays (TMAs). We also further investigated EZH2 as a marker for response to HDAC inhibitors.

      Methods:
      We analyzed EZH2 and HDAC1 mRNA expression in two lung adenocarcinoma datasets (MDACC n=152, and TCGA n=308), and correlated the gene expression with tumors’ clinico-pathological characteristics and patients’ outcome. To study the association of EZH2 and HDAC1 expression with response to the HDAC1 inhibitor suberanilohydroxamic acid (SAHA), we examined mRNA and protein expression by RT-PCR and Western blot, respectively, in twelve lung adenocarcinoma (LUAD) cell lines at baseline and after overexpression or knock-down of EZH2 or HDAC1 gene expression using siRNA. Response to (SAHA) in cell lines was measured by MTT assay and correlated with protein and mRNA expression levels of EZH2 and HDAC1.

      Results:
      Direct and positive correlation was found between EZH2 and HDAC1 expression NSCLC cell lines (P <0.0001). This correlation was confirmed in NSCLC specimens from MDACC (Spearman’s correlation r=0.416; p < 0.0001) and TCGA datasets (r=0.221; p <0.0001).Patients with high EZH2 and high HDAC1 expression in stage I NSCLC specimens of MDACC and TCGA datasets had lowest survival compared to the patients who had either or both low expressions. Overall survival in the univariate analysis (MDACC dataset; Hazard Ratio (HR)=2.97; p=0.031 and TCGA dataset; HR=2.6 and p=0.041) and multivariate analysis (MDACC; HR=2.92 and p=0.034 and TCGA; HR=3.17 p=0.016). When EZH2 expression was knock down, there was a significant reduction in HDAC1 expression; conversely, when HDAC1 was knocked down EZH2 expression was also decreased. These concordant change in expression was seen both at the protein and mRNA level. Importantly, while all 8 cell lines with high EZH2 protein expression responded to SAHA treatment with average inhibition rate reaching 73.1%, three out of four cell lines with low EZH2 expression had a significantly lower response rate to SAHA inhibition with average inhibition rate 43.2% (P<0.0001). Additionally, altering the expression of EZH2 concordantly altered the sensitivity to SAHA i. e. forced increased expression of EZH2 increased the response to SAHA and vice versa.

      Conclusion:
      Our data suggest that EZH2 and HDAC expression are correlated in LUAD cell lines in human tissue microarrays and overexpression of both is a negative prognostic indicator. Additionally we show that increased EZH2 expression predicts for response to HDAC inhibitors and thus could serve as a biomarker for selecting LUAD patients with HDAC inhibitors.

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      MINI21.08 - Bombesin Receptor Subtype-3: An Underappreciated Growth Factor in Lung Cancer (ID 722)

      P. Moreno, T.W. Moody, S.H. Lee, S.A. Mantey, R.T. Jensen

      • Abstract
      • Presentation
      • Slides

      Background:
      Human bombesin receptors (BnR) are one of the most frequently over-expressed receptor families by human lung-cancers. It is known the activation of the classical members of the BnR family (GRPR, NMBR), causes a marked effect on cell-signaling and growth, often autocrine in nature, on lung-cancer cells. In addition, it has been discovered that the orphan receptor related to the BnR family, BRS-3, is widely distributed in central/peripheral normal tissues, and numerous tumors include lung-cancer cells. However, in contrast to the classical BnRs (GRPR, NMBR), BRS-3 has received little attention in lung-cancer in large part due to the fact its natural ligand is still unknown, and also because, until recently, the lack of specific pharmacological tools to study it. To address this, in this study, we examined the frequency of hBRS-3 expression in lung-cancer cells, and the effects of specific hBRS-3 activation on cell-signaling and cell-function (growth) in different lung-cancer cell lines.

      Methods:
      17 human lung-cancer (LC) cell lines were studied (9 NSCLC, 8 SCLC), as well as hBRS3 transfected H1299 and Balb 3T3 cells. The BRS-3 selective agonist, MK-5046 and selective BRS-3 antagonist, Bantag-1 were used. BnR expression was assessed by PCR using specific primers for hBRS3, hGRPR or hNMBR. Receptor activation was determined by assessing PLC and MAPK cascade activation using Western Blotting, and cytosolic Ca[2+] release. Proliferation was studied by clonogenic and [[3]H]-Thymidine assays, and EGFR transactivation was assessed using Western blotting.

      Results:
      Of the 17 LC cell lines, 9 (53%) express hBRS3 [H358, H460, H520, H720, H727, H69, H82, N417, H510], 14 (82%) express hGRPR [H28, H157, H358, H520, A549, H838, H1299, SK-LU-1, H720, H727, H69, H82, H345, H510] and 13 (77%) express hNMBR [H28, H157, H358, A549, H838, H1299, SK-LU-1, H720, H727, H82, H345, N417, H510]. MK-5046 stimulated PLC activation in 6/9 cells which express hBRS3 (H358, H720, H727, H69, H82, N417), and MAPK activation in all 9 hBRS3 cell lines. Cytosolic Ca[2+] increased with MK-5046 addition in all hBRS-3-containing cells, included Balb and H1299 transfected cells, except in H358 cells. Similarly, MK-5046 increased [3]H-Thymidine uptake in 5/9 cells (H460, H520, H720, H727, H82, H510), as well as in Balb and H1299 hBRS-3 transfected cells, and this increase was in a dose-response manner in H727, H69 and N417 cells. MK-5046 stimulated the clonal growth of N417 and H727 cells. MK-5046 addition to H358, H460, H727 (NSCLC) and H69, N417, H510 (SCLC) caused Tyr[1068] phosphorylation of the EGFR.

      Conclusion:
      These results show the orphan human BnR, hBRS-3 is present in more than one-half of human lung cancer cells. Furthermore, these receptors are functional with their activation effecting cell signaling (MAPK, PLC, Ca[2+]) and cell growth. Transactivation of EGFR is likely an important transduction cascade. These results suggest this orphan BnR, similar to classical BNRs, will be important to assess for growth effects and expression in human lung tumors, and its pharmacological inhibition may be a useful therapeutic approach.

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      MINI21.09 - Discussant for MINI21.06, MINI21.07, MINI21.08 (ID 3422)

      J.S. Lee

      • Abstract
      • Presentation

      Abstract not provided

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      MINI21.10 - The TORK/DNA-PK Inhibitor CC-115 Shows Combination Anti-Proliferative Effects with Erlotinib in NSCLC Cells Resistant to EGFR Inhibition (ID 641)

      S. Ekman, D. Chan, M. Wynes, Z. Zhang, K. Hege, E. Filvaroff, H. Raymon, R. Hassan, L. Rozeboom, F.R. Hirsch

      • Abstract
      • Slides

      Background:
      In non-small cell lung cancer (NSCLC), activation of the phosphoinositide-3-kinase (PI3K)/mTOR pathway is common in tumors resistant to Epidermal Growth Factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). CC-115 (Celgene Corporation), an mTOR kinase inhibitor that targets both mTORC1 and mTORC2 as well as DNA-dependent protein kinase (DNA-PK), is currently under early clinical development. We evaluated CC-115 in combination with Erlotinib to overcome resistance to EGFR tyrosine kinase inhibition in non-small cell lung cancer (NSCLC) cell lines and xenografts in nude mice.

      Methods:
      In the present study we investigated whether CC-115 is able to increase the therapeutic effect of the EGFR TKI Erlotinib in several different NSCLC cell lines which exhibit intermediate or high resistance to EGFR TKIs: A549, H1975, H1650, HCC95, H2122 and H23. Mechanisms of inhibition were analyzed with assays for proliferation, apoptosis, and cell cycle progression. Cell signaling activity was analyzed using phospho-specific antibodies in Western blotting. Xenograft mice studies were performed to confirm the results in vivo.

      Results:
      CC-115 demonstrated anti-proliferative activity in NSCLC cell lines with various degrees of sensitivity as reflected in different IC50 values, ranging from 0.07 up to 6.9 mM. The anti-proliferative efficacy of Erlotinib was increased in the NSCLC cells synergistically by combination treatment with CC-115 with combination indices down to 0.04-0.2, indicating strong synergy. The synergistic, anti-proliferative effect of the combination treatment could be explained by increased cell cycle arrest and inhibition of signaling components in the mTOR pathway, especially 4E-BP1. In vivo studies in mice xenografts demonstrated a strong synergistic effect of the combination treatment of Erlotinib and CC-115.

      Conclusion:
      We demonstrate that the therapeutic effect of the EGFR tyrosine kinase inhibitor Erlotinib can be increased by simultaneous treatment with the mTOR kinase/DNA-PK inhibitor CC-115, justifying further clinical studies in lung cancer patients with primary or acquired resistance to EGFR TKIs.

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      MINI21.11 - A Novel Cell Line Model of EGFR Exon 20 Insertion Mutations (ID 2828)

      A. Estrada-Bernal, A.T. Le, H. Zhou, S.A. Noonan, D.L. Aisner, R. Camidge, R.C. Doebele

      • Abstract
      • Presentation
      • Slides

      Background:
      In-frame insertions in exon 20 of EGFR are infrequent activating mutations in the tyrosine kinase domain that have decreased sensitivity to EGFR inhibitors and currently have no available targeted therapies. In vitro studies ectopically expressing some of the common insertions (3 to 21 bp between codons 762 and 770) show reduced sensitivity to EGFR tyrosine kinase inhibitors (TKIs). Non-small cell lung cancer (NSCLC) patients whose tumors harbor these mutations do not respond to EGFR kinase inhibitors. To date, there are no known patient-derived cell lines that harbor the EGFR exon 20 insertions that recapitulate patient insensitivity to EGFR TKIs. Here we report the isolation and characterization of a patient derived cell line with an EGFR exon20 insertion.

      Methods:
      The CUTO-14 cell line was derived from a malignant pleural effusion of a lung adenocarcinoma patient harboring the EGFR exon 20 insertion p.A767_V767dupASV after obtaining IRB-approved informed consent. PCR amplification of EGFR exon 20 and subsequent Sanger sequencing was performed on genomic DNA isolated from CUTO-14. H3255 (L858R) and HCC827 (exon 19 del) cell lines were used as controls because they harbor sensitizing EGFR mutations. Cell viability was evaluated by MTS proliferation assay. Phosphorylation status and signaling was analyzed by western blot and an EGFR phosphorylation array. For tumor xenograft studies, nude mice were injected with 1.5 x 10[6] cells in matrigel and evaluated weekly for tumor growth.

      Results:
      Genomic sequencing of CUTO-14 demonstrated that the cell line maintains the pA767_V767dupASV EGFR exon 20 insertion. CUTO-14 showed relative resistance to gefitinib inhibition compared to HCC827 and H3255 in ERK1/2 phosphorylation assays. CUTO-14 also demonstrated reduced sensitivity to gefitinib compared to HCC827 and H3255 in cell proliferation assays. Tumor formation was observed in mice after injection in nude mice.

      Conclusion:
      CUTO-14 cells represent a novel model for the investigation of therapeutic strategies for EGRF exon 20 insertions mutations. The cell line has the ability to develop tumors in vivo and importantly shows reduced sensitivity to EGFR TKIs mimicking the lack of response in patients with these mutations.

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      MINI21.12 - Identification of a First in Class TWIST1 Inhibitor with Activity in KRAS Mutant NSCLC (ID 1616)

      L. Mazzacurati, J. Cades, S. Chatley, Z. Yochum, K. Nugent, A. Somasundarum, Y. Cho, C.M. Rudin, P. Tran, T.F. Burns

      • Abstract
      • Presentation
      • Slides

      Background:
      Although a large fraction of non-small cell lung cancers (NSCLC) are dependent on defined oncogenic driver mutations, little progress has been made in the treatment of patients with the most common driver mutation, mutant KRAS. We previously demonstrated that the basic helix-loop-helix transcription factor, Twist1 cooperates with mutant Kras to induce lung adenocarcinoma in mouse models, and that inhibition of Twist1 in murine models and KRAS mutant NSCLC cell lines led to oncogene-induced senescence (OIS) and in some cases, apoptosis. Therefore, targeting the TWIST1 pathway represents an exciting and novel therapeutic strategy which may have a significant clinical impact.

      Methods:
      We used gene expression profiles from KRAS mutant human NSCLC cell lines following shRNA-mediated TWIST1 knockdown to perform connectivity map (CMAP) analysis to identify pharmacologic inhibitors of TWIST1. Growth inhibition was determined through the colony formation and MTS assays. Apoptosis (cl-PARP, active anti-C3) and OIS (SA-β-Gal) was assessed. Genetic (shRNA) and pharmacologic inhibition of the TWIST1-E2A pathway was performed. Lung tumor burden as well as levels of TWIST1 protein, apoptosis and proliferation were measured after treatment with harmine in the CCSP-rtTA/tetO-KrasG12D/Twist1-tetO7-luc(CRT) mice.

      Results:
      We found that several of our CMAP compounds had significant growth inhibitory effects in NSCLC cell lines. Interestingly, a family of related harmala alkaloids including harmine ranked highly in our CMAP analysis. We observed that harmine could inhibit growth in KRAS mutant NSCLC cell lines through the induction of OIS or apoptosis and phenocopied genetic inhibition of TWIST1. Remarkably, harmine treatment led to TWIST1 protein degradation as well as degradation of its binding partners, the E2A proteins, E12/E47. Furthermore, the growth inhibitory effects of the harmala alkaloids correlated with the ability to degrade TWIST1 and were independent of its ability to inhibit the DYRK kinases. In addition, we demonstrated that heterodimer formation of TWIST1/E12/E47 resulted in a reciprocal stabilization of each binding partner and that E12/E47 are required for TWIST1 mediated suppression of OIS and apoptosis. Importantly, we found that harmine preferential targets the TWIST1-E12 heterodimer for degradation and the growth inhibitory effects of harmine are in due in at least part to the ability to inhibit the TWIST1/E12/E47 heterodimer as overexpression of the E2A proteins can suppress harmine induced cytotoxicity. Finally, we have demonstrated that harmine treatment lead to Twist1 protein degradation and tumor growth inhibition in our Kras[G12D]/Twist1 murine model of lung adenocarcinoma. We are currently testing and designing structure analogs of the initial candidate agents to develop more specific and potent inhibitors of TWIST1.

      Conclusion:
      We have identified a novel TWIST1 inhibitor harmine that induces degradation of TWIST1 and its binding partners, E12/E47 and inhibits the growth of KRAS mutant NSCLC both in vitro and in vivo. Therefore, we believe that targeting the TWIST1-E2A pathway would be an effective therapeutic strategy. Since TWIST1 is essential not only for KRAS mutant NSCLC but more broadly for oncogene driven NSCLC, the development of this novel class of TWIST1 inhibitors could have a significant clinical impact.

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      MINI21.13 - Discussant for MINI21.10, MINI21.11, MINI21.12 (ID 3423)

      G. Giaccone

      • Abstract
      • Presentation

      Abstract not provided

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    ORAL 37 - Novel Targets (ID 146)

    • Event: WCLC 2015
    • Type: Oral Session
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 8
    • +

      ORAL37.01 - FISHing TRK Activation by Gene Rearrangements in Non Small Cell Lung Cancer (ID 834)

      M. Varella-Garcia, S.L. Kako, C.M. Nguyen, S. Saichaemchan, W. Ariyawutyakorn, S. De, S.B. Keysar, A. Jimeno, M. Roncalli, A. Santoro, L. Toschi, A.T. Le, D.L. Aisner, R.C. Doebele

      • Abstract
      • Presentation
      • Slides

      Background:
      The tropomyosin-receptor kinase (TRK) family includes genes important in nervous system development, NTRK1 (N1), NTRK2 (N2) and NTRK3 (N3). Oncogenic activation was identified long ago as N1 fusions in colon cancer and numerous fusions have been recently identified affecting all family members in multiple tumor types. This study developed FISH reagents for molecular diagnosis of NTRK rearrangements and investigated their prevalence in NSCLC. The ultimate goal is to validate a clinical assay for selection of patients who may benefit from novel tyrosine kinase inhibitors (TKIs) targeting these fusion proteins.

      Methods:
      Three FISH break-apart (BA) probe sets (LDTs) were tailored for diagnosis of rearrangements in N1, N2 and N3 and tested in specimens with known genomic status for these genes: cell lines KM12 (N1), CUTO3 (N1), MO-91 (N3), xenograft CULC001 (N1), and clinical specimens, and used to screen resected NSCLC. The LSI NTRK1 Cen and Tel probes (Abbott Molecular) were also tested. A specimen was positive for individual rearrangement when ≥15% tumor cells had split or single 3’,5’ signals. Moreover, a 6-target, 2-color FISH probe including the 3’N1, 3’N2 and 3’N3 sequences labeled in red and the 5’N1, 5’N2 and 5’N3 sequences labeled in green (TRKombo) was designed for rapid screening of TRK rearrangements in clinical specimens.

      Results:
      Results were obtained in 443, 410, and 434 examined NSCLC and positive patterns were detected in 5, 5 and 1 specimens, respectively for N1, N2, and N3. These 11 positive patients had age ranging from 38y to 76y, gender 6 male:5 female, and were current (4), former (5) or never (2) smokers. Histology was predominantly adenocarcinoma (7) but also included squamous cell (3) and neuroendocrine morphology (1). Unique to the N1 assay was the observance of FISH signal fusions where the 5’N signals appeared as doublet in >20% of the NSCLC specimens, which was determined to be copy number variation due to segmental duplication. Other atypical patterns were observed for all three targets and included doublets of the FISH fusion signals (18%, 14% and 9% respectively) and gene clusters (~5% for each). Twenty specimens (pre-clinical models and clinical cases) characterized as positive by the LDT N1 and by next generation sequencing (NGS) or atypical by the LDT NTRK1 BA were blindly analyzed with the LSI NTRK1 probe set and the results were reproducible, with brighter intensity of the fluorescent signals for the LSI probe. These specimens (positive by FISH and several atypicals) are currently under investigation to characterize the sequence specific genomic rearranged region by using a custom targeted, capture-based NGS panel (NimbleGen, Roche). The TRKombo screening probe performed well in blinded experiment using validation set including pre-selected positive and negative specimens and is under testing in clinical tissue sections.

      Conclusion:
      N1, N2 and N3 fusions were detected by FISH in a subset of lung carcinomas including adeno, squamous and neuroendocrine tumors. Optimization of molecular panels for diagnosis of these rearrangements is relevant since they represent a sizeable number of cases across multiple tumor types and there are numerous targeted inhibitor agents under development.

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      ORAL37.02 - Protein Tyrosine Phosphatase Non Receptor 11 PTPN11/Shp2 as a Driver Oncogene and a Novel Therapeutic Target in Non-Small Cell Lung Cancer NSCLC (ID 1590)

      Y. Elamin, S. Toomey, A. Carr, K. Gately, S. Rafee, P. Morris, J. Crown, O. Breathnach, K.J. O'Byrne, B. Hennessy

      • Abstract
      • Slides

      Background:
      PTPN11/Shp2 somatic mutations occur in 25% of Juvenile myelomonocytic leukemias (JMML) and less commonly in adult solid tumors. PTPN11/Shp2 activates the mitogen-activated protein kinase (MAPK) and the phosphatidylinositide 3-kinase (PI3K) pathways. Accordingly, PTPN11/Shp2 mutations were shown to sensitize leukemia cells to MEK and PI3K inhibitors.

      Methods:
      We applied mass-spectrometry based genotyping (Sequenom Inc., Germany) to DNA extracted from tumor and matched normal tissue of 356 NSCLC patients (98 adenocarcinomas and 258 squamous cell (SCC)). PTPN11/Shp2 constructs with mutations (E76A, A72D) were generated and stably expressed in IL-3 dependent BaF3 cells and NSCLC cell lines (H1703, H157). The acquisition of MAPK and PI3K pathways activation was evaluated using western blotting and reverse phase protein array (RPPA). PTPN11/Shp2 phosphatase activity was measured in whole cell protein lysates using Shp2 assay kit (R&D Systems).

      Results:
      Somatic PTPN11/Shp2 hotspot mutations occurred in 3 (3.1%) and 9 (3.4%) of adenocarcinomas and SCCs, respectively. Mutant PTPN11/Shp2, compared to PTPN11/Shp2 wild type, promoted ten-fold IL-3 independent BaF3 cell survival. BaF3, H1703, and H157 cells expressing mutant PTPN11/Shp2 exhibited increased PTPN11/Shp2 phosphatase activity, phospho-ERK1/2, and phospho-AKT levels. Sequencing of NSCLC cell lines revealed that NSCLC H661 cell line has a PTPN11/Shp2 activating mutation (N58S). H661 had significantly higher PTPN11/Shp2 phosphatase activity when compared to PTPN11 wild-type H1703 and Calu3 NSCLC cells. Since the biological functions of PTPN11/Shp2 are mediated through its phosphatase domain, we stably expressed the inactivating PTPN11/Shp2 phosphatase domain mutation (C459S) in H661, H1703 and H157 cells resulting in catalytically inactive PTPN11/Shp2. This led to decreased phospho-ERK1/2 levels in all three cell lines. Importantly, the inactivation of PTPN11/Shp2 resulted in decreased phospho-AKT levels in H661 cells (PTPN11-mutated) and had no effect on phospho-AKT levels in the PTPN11/Shp2-wild type H1703 and H157 cells. Taken together, this data suggests that PTPN11/Shp2 activating mutations are oncogenic in NSCLC cells. Moreover, these findings reveal that PTPN11/Shp2 mutations may selectively activate the PI3K pathway in NSCLC cells. Parental H661 (PTPN11-mutated, KRAS and PIK3CA-wild type), parental H1703 (PTPN11, KRAS and PIK3CA-wild type) and parental H157 (KRAS-mutated, PTPN11 and PIK3CA-wild type) cells were treated with the novel MEK (BAY86-9766) and PI3K (BAY80-6946) inhibitors. IC50 values (table 1) suggest that PTPN11-mutated NSCLC cells have modest sensitivity to MEK inhibitors and profound sensitivity to PI3K inhibitors.

      Table 1 IC 50 valuse
      Cell Line BAY86-9766 (nM) BAY80-6946 (nM)
      H661 2880 ± 600 13 ± 4.7
      H157 1450 ± 520 < 50% inhibition @ 200
      H1704 < 50% inhibition @ 10000


      Conclusion:
      PTPN11/Shp2 demonstrates the in vitro features of a driver oncogene, and potentially represents a new target in NSCLC.

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      ORAL37.03 - Discussant for ORAL37.01, ORAL37.02 (ID 3464)

      L.E. Raez

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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      ORAL37.04 - Comprehensive Genomic Profiling (CGP) of Advanced Cancers Identifies MET Exon 14 Alterations That Are Sensitive to MET Inhibitors (ID 3156)

      G.M. Frampton, S.M. Ali, J.W. Goldman, C. Lee, J. Weiss, J.A. Bufill, R. Salgia, M. Jahanzeb, K. Konduri, P. Forde, D. Morosini, J.S. Ross, P.J. Stephens, V. Miller, I. Ou

      • Abstract
      • Presentation
      • Slides

      Background:
      Amplifications and activating mutations in the c-MET proto-oncogene are known oncogenic drivers that have proven responsive to targeted therapy. Mutations causing skipping of MET exon 14 are also oncogenic, but less well characterized. We undertook comprehensive genomic profiling (CGP) of a large series of advanced cancers to further characterize MET exon 14 alterations.

      Methods:
      DNA was extracted from 40 microns of FFPE sections from 38,028 advanced cancer cases. CGP was performed on hybridization-captured, adaptor ligation based libraries to a mean coverage depth of >500x using three versions of the FoundationOne test. Hybridization capture baits for the MET gene were identical for all three versions of the test. Base substitution, indel, copy number alteration, and rearrangement variant calls were examined to identify those nearby to the splice junctions of MET exon 14. These genomic alterations were then manually inspected to identify those likely to affect splicing of exon 14, or delete the exon entirely.

      Results:
      221 cases harboring MET ex14 alterations were identified. These patients had a median age of 70.5 years (range 15-88), with 97 males and 124 females. The cases were lung carcinoma (193), carcinomas of unknown primary (15), brain glioma (6), and one each of adrenal cortical carcinoma, hepatocellular carcinoma, histiocytic sarcoma, renal cell carcinoma, rhabdomyosarcoma, skin merkel cell carcinoma, and synovial sarcoma. The majority were stage IV. Identification of this alteration has lead to treatment with MET inhibitors such as crizotinib, and to durable partial responses or better exceeding 3 months in histiocytic sarcoma (1), sarcomatoid lung carcinoma (1), and nsclc (1+). Multiple patients (5+) have initiated treatment on either crizotinib or MET inhibitors in clinical development, and additional outcome data will be reported. One patient with locally advanced unresectable disease harbored a MET exon 14 skipping alteration. On initiation with treatment with an MET inhibitor, symptomatic relief was observed in 3 days, radiographic response was observed at two weeks, and resection was performed 8 weeks after initiation of the MET inhibitor.

      Conclusion:
      MET exon 14 alterations define a hereto unrecognized population of advanced cancer cases, particularly in NSCLC. Multiple case reports demonstrate that these alterations confer sensitivity to multiple small molecule MET inhibitors. This finding expands the population of advanced NSCLC patients who can derive benefit from MET-targeted therapies.

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      • Abstract
      • Slides

      Background:
      The reported prevalence of MET gene amplification in non-small cell lung cancer (NSCLC) varies from 0-21% and clinical correlations are emerging slowly. In a well-defined NSCLC cohort of the ETOP Lungscape program, we explore the epidemiology, the natural history of MET amplification and its association with MET overexpression, overall survival (OS), relapse-free survival (RFS) and time to relapse (TTR).

      Methods:
      Resected stage I-III NSCLC, identified based on the quality of clinical data and FFPE tissue availability, were assessed for MET gene copy number (GCN) and expression analysis using silver in-situ hybridization (SISH) and immunohistochemistry (IHC), respectively, on TMAs (MET and centromere-specific probes; anti total c-MET antibody, clone SP44; Ventana immunostainer). MET amplification was defined as MET/centromere ratio ≥2 with average MET GCN ≥4, high MET GCN at two levels as ≥median CGN and ≥5 (irrespective of amplification) and MET IHC+ as 2+ or 3+ intensity in ≥50% of tumor cells. Sensitivity analysis to define the amplification’s thresholds was also performed. All cases were analysed at participating pathology laboratories using the same protocol, after successful completion of an external quality assurance (EQA) program.

      Results:
      Currently 2709 patients are included in the Lungscape iBiobank (median follow-up 4.8 years, 53.3% still alive). So far, 1547 (57%) have available results for MET GCN with amplification detected in 72 (4.7%; 95%CI: 3.6%, 5.7%) and high MET GCN (≥5) in 65 (4.2%; 95%CI: 3.2%, 5.2%). The median value of average MET GCN per cell is 2.3. IHC MET expression is available for 1515 (98%) of these cases, 350 (23%) of which are MET IHC positive [170 cases (49%) 3+, 180 (51%) 2+]. The median age, for the cohort of 1547 patients, is 66.2 years, with 32.8% women, and 13.5%, 29.7%, 54% never, current, former smokers, respectively. Stage distribution is: IA 23.6%, IB 24.6%, IIA 17%, IIB 12.1%, IIIA 20.9%, IIIB 1.8%, while 52.7%, are of adenocarcinoma and 40.0% of squamous histology. MET amplification and high MET GCN (≥5) are not significantly associated with any histological tumor characteristics or stage (multiplicity adjusted alpha: 0.005). High MET GCN (≥2.3) is less frequent in current smokers (38.3% vs. 55.6% for former or non-smokers, p<0.001). MET amplification and high MET GCN are significantly associated with IHC MET positivity (p<0.001 in all cases). MET amplification is present in 9.7% of IHC MET+ vs 3.1% of IHC MET- patients and high MET GCN (≥5) in 8.6% of IHC MET+ vs 2.8% of IHC MET- patients. MET amplification ranges from 0 to 16% between centers, while high MET GCN (≥5) and (≥2.3) from 0% to 12%, and 11.8% to 98.9%, respectively. MET amplification and both levels of high MET GCN are not associated with OS, RFS or TTR.

      Conclusion:
      The preliminary results for this large, predominantly European, multicenter cohort demonstrate that MET amplification assessed by SISH prevails in 4.7% of NSCLC, is associated with strong MET expression, and has no influence on prognosis. The large inter-laboratory variability in GCN despite EQA efforts may highlight a critical challenge of MET SISH analysis in routine practice.

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      ORAL37.06 - Defining MET Copy Number Driven Lung Adenocarcinoma Molecularly and Clinically (ID 2379)

      S.A. Noonan, L. Berry, D. Gao, X. Lu, A.E. Barón, P. Chesnut, N. Hart, J. Sheren, D.L. Aisner, D.T. Merrick, R.C. Doebele, M. Varella-Garcia, R. Camidge

      • Abstract
      • Presentation
      • Slides

      Background:
      Increases in MET copy number define an oncogenic driver state sensitive to MET inhibition (Camidge et al, ASCO 2014). However, the level at which the genomic gain is relevant remains uncertain. When testing is performed by fluorescence in situ hybridization (FISH), variable cut-points in both mean MET/cell and MET/CEP7 ratio have been used. Partially overlapping datasets from the Lung Cancer Mutation Consortium (LCMC1) and Colorado Molecular Correlates (CMOCO) Laboratory were explored for a distinct MET-copy number driven lung adenocarcinoma subtype.

      Methods:
      MET was assessed by FISH. Data from non-adenocarcinomas and EGFR mutant patients with acquired resistance to an EGFR inhibitor were excluded. Positivity criteria were mean MET/cell ≥5 (low ≥5-<6, intermediate ≥6-<7, high ≥7) or MET/CEP7 ≥1.8 (low ≥1.8-≤2.2, intermediate >2.2-< 5, high ≥5). MET metrics were compared by race, sex, smoking status, stage at diagnosis, number of metastatic disease sites, site of metastases, presence of other known drivers (EGFR, KRAS, ALK, ERBB2, BRAF, NRAS, ROS1 and RET), response to first line chemotherapy and overall survival using Fisher’s exact tests, chi-square tests, Spearman correlations and log-rank tests, as appropriate. Statistical significance was set at the 0.05 level without adjustment for multiple comparisons.

      Results:
      1164 unique adenocarcinomas were identified (60% female, 85% Caucasian, 66% ex/current smokers). MET/CEP 7 data was available on 1164 and mean MET/cell on 700. 52/1164 (4.5%) had MET/CEP7 ≥1.8 (48% female, 83% Caucasian, 69% smokers). 50/52 (98%) had ≥1 other oncogenic driver tested (25/50 (50%) positive). 113/700 (16%) had mean MET/cell ≥ 5 (57% female, 82% Caucasian, 58% smokers). 109/113 (96%) had ≥ 1 other oncogenic driver tested (73/109 (67%) positive). Among patients with ≥1 additional driver oncogene tested, alternate drivers in low, indeterminate and high categories of mean MET/cell were 44/60 (67%), 17/24 (70%) and 12/28 (43%) respectively and for MET/CEP7: 16/29 (55%), 9/18 (50%) and 0/4 (0%) respectively. MET positive with additional drivers were excluded from further analyses. Men exceeded women in MET/CEP7 (men 4% vs women 1.6%, p = 0.019) and mean MET/cell positive cases (men 9.6% vs women 5.4%, p = 0.058). 6.4% of adrenal metastasis cases were MET/CEP7 positive vs 2% all other sites, p=0.031. Mean MET/cell: 12% adrenal vs 5% other sites, p=0.082. MET/CEP7 or mean MET/cell positive and negative groups did not differ by other variables (p > 0.05).

      Conclusion:
      The proportion of ‘MET positive’ adenocarcinomas varies by definition and positivity cut-point. Mean MET/cell ≥5 defines nearly 4x more positives than MET/CEP7 ≥1.8 and no mean MET/cell positive category was free from overlap with other drivers. As only high MET/CEP7 had no overlap with other drivers, MET/CEP7 ≥ 5 is the clearest candidate for a pure MET-copy number driven state, however cases free from other drivers do exist at lower MET positivity levels. MET/CEP7 positive cases free from other known drivers are more likely to be male, but unlike other known oncogenic states, race and smoking status are not significant in determining positivity. MET positivity may have a specific biological phenotype, being more likely to present with adrenal metastases.

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      ORAL37.07 - Lung Cancer Mutation Consortium Pathologist Panel Evaluation of MET Protein (ID 2129)

      T.A. Boyle, F. Khalil, M. Mino-Kenudson, A. Moreira, L. Sholl, G. Sica, M.Z. Knight, A.A. Kowalewski, K. Ellison, C.J. Rivard, L. Berry, H. Chen, K. Kugler, B.E. Johnson, D.J. Kwiatkowski, P.A. Bunn, Jr, F.R. Hirsch

      • Abstract
      • Presentation
      • Slides

      Background:
      MET is a receptor tyrosine kinase with frequently activated signaling in lung cancers. Multiple studies indicate that MET overexpression correlates with poor clinical prognosis. Tumors with MET amplification and overexpression may respond better to MET inhibitors than tumors with low expression. The prevalence of MET overexpression in lung cancer cohorts has varied from 20%-80%, as has the proportion of patient’s testing positive for prospective clinical trials with entry based on MET overexpression. The Lung Cancer Mutation Consortium (LCMC) Pathologist Panel endeavored to standardize evaluation of MET protein expression with “Round Robin” conferences.

      Methods:
      508 FFPE non-small cell lung cancer specimens were stained by immunohistochemistry for MET protein expression (SP44 antibody, Ventana). Seven pathologists from LCMC sites with specialized training in MET scoring evaluated 78 Aperio-scanned images of MET-stained slides in two successive rounds of 39 different cases per round. The percentage of tumor cells with membranous and/or cytoplasmic staining at different intensities were evaluated with H-scores ranging from 0 to 300. Overall group and individual pathologist’s scores were compared with intraclass correlation coefficients (ICCs). Between rounds, a “Round Robin” teleconference was conducted to review discordant cases and improve consistency of scoring. Steps to improve scoring included: review of a Roche MET training document, sharing pictures of cases with concordant scores (Figure 1), and provision of H&E images for the second round to facilitate identification of tumor areas. Figure 1



      Results:
      The overall average MET H-score for the 78 cases was 165.3 (H-score range: 42.5-279.7). The average H-score was <125 for 14 specimens, 125-175 for 35 specimens, and >175 for 29 specimens. The overall group ICC comparing the consistency of H-scores from all 7 pathologists improved from 0.50 (95% confidence interval: 0.37-0.64, “fair” correlation) for the first scoring round to 0.74 (95% confidence interval: 0.64-0.83, “good” correlation) for the second round. A comparison of the individual pathologist’s ICCs demonstrated improved individual scoring consistency for all seven pathologists between rounds with an average of 0.64 (“moderate” correlation, range 0.43-0.76) for the first round and 0.82 (“almost perfect” correlation, range 0.75-0.93) for the second round.

      Conclusion:
      Development of standardized, reproducible strategies for evaluation of complex biomarkers, such as MET, are critical to clinical trial design. The consistency of scoring for MET protein expression and other biomarkers may be improved by continuous training and communication between pathologists with easy access to H&E images and other visual aids.

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      ORAL37.08 - Discussant for ORAL37.04, ORAL37.05, ORAL37.06, ORAL37.07 (ID 3465)

      G.J. Weiss

      • Abstract
      • Presentation

      Abstract not provided

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    ORAL 41 - Immune Biology, Microenvironment and Novel Targets (ID 159)

    • Event: WCLC 2015
    • Type: Oral Session
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 8
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      ORAL41.01 - Tumor-Infiltrating B Lymphocytes Characterized by CD79a and MUM1 Independently Predict Outcome in Patients with Non-Small Cell Lung Cancer (ID 485)

      R.N. Fischer, A.H. Scheel, S.I. Rothschild, H.A. Schlößer, J. Wolf, R. Büttner, S. Ansén, M.S. Von Bergwelt-Baildon

      • Abstract
      • Presentation
      • Slides

      Background:
      Tumor-infiltrating lymphocytes play an important role in cell-mediated immune-destruction of cancer cells and tumor growth control. For non-small cell lung cancer (NSCLC) a prognostic role of T cell subtypes, natural killer cells and dendritic cells within the tumor stroma has been described. Here, we studied the role of tumor-infiltrating B cells characterized by CD79a (B-cell antigen receptor complex-associated protein alpha chain) and MUM1 surface expression (Multiple myeloma oncogene 1) in patients with NSCLC. To our knowledge, this study represents the so far largest cohort analyzing the prognostic impact of tumor-infiltrating B-cells.

      Methods:
      B cell infiltration was quantified using immunohistochemistry and antibodies to CD79a (Dako, clone JCB117) and MUM1 (Dako, clone MUM1p) on tissue microarrays (TMA) of paraffin embedded tumor sections. Genetic driver mutations were identified by next-generation sequencing and FISH analysis. SPSS version 20 (IBM Corp.) was used for statistical analysis. Chi-square test, Fisher’s exact test, Kaplan-Meier survival analysis and Cox-regression analysis were used as appropriate.

      Results:
      478 tissue samples from NSCLC patients were available for immunohistochemistry. 65% of patients were male, median age was 66 years. 56% had adenocarcinoma and 39% squamous cell histology. 61% of patients had localized disease (stage I/II), 30% locally advanced disease (stage III) and 6% were diagnosed with stage IV. Frequencies of genomic aberrations are listed in Table 1. CD79a and MUM1 positive cells were detected in 40.8% (195/478) and 40.2% (192/478) of the analyzed NSCLC tissue samples, respectively. B cell infiltration was not associated with clinical or histo-pathological characteristics. MUM1 expression was associated with a significantly prolonged overall survival (median OS 54 vs. 40 months, p=0.025). The expression of CD79a showed a trend towards a better outcome (median OS 49 vs. 40 months, p=0.069). In the multivariate analysis B cell infiltration characterized by CD79a/MUM1 positivity was an independent prognostic marker for survival (p=0.045) as was MUM1 expression (p=0.031). Table 1.

      Genomic aberration Number of patients Frequency
      TP53 mutation 136 28.5%
      KRAS mutation 65 13.6%
      FGFR1 amplification 28 5.9%
      PIK3CA mutation 17 3.6%
      EGFR mutation 12 2.5%
      ALK fusion 4 0.8%
      ERBB2 mutation 4 0.8%
      ERBB2 amplificiation 4 0.8%
      ROS1 fusion 2 0.4%
      BRAF mutation 2 0.4%
      DDR2 mutation 2 0.4%
      FGFR2 mutation 1 0.2%


      Conclusion:
      B cell infiltration characterized by immunohistochemical positivity for CD79a and MUM1 represents an independent prognostic marker in NSCLC. This finding supports the hypothesis of a B cell-mediated anti-tumor immunity.

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      ORAL41.02 - Novel Mechanism of Immune-Tolerance and Cancer Metastasis Due to Aberrant Expression of Natural Killer Immunoglobulin-Like Receptors (KIRs) (ID 2199)

      D.C. Chan, Z. Zhang, D. Zheng, T. Chan, J. Dipaola, B. Warren, M. Berg, K. Horwitz, N. Ahn, L. Lanier, P.A. Bunn, Jr

      • Abstract
      • Presentation
      • Slides

      Background:
      Natural Killer (NK) cells are a major defense to eliminate cancer cells. Cancer cells and metastases may have aberrantly expressed KIRs to prevent killing by NK cells. In addition, platelets may inhibit NK killing of cancer cells. Metastatic cancer cells spread through blood vessels where they constantly interact with platelets by forming tumor microemboli and thereby protected from otherwise rapid elimination from host immune defense cells such as NK cells. Here, using an in vivo model of cancer metastasis in athymic nude mice by directly injecting cancer cells into the blood stream, we study the ability of platelets and KIRs in helping cancer cells to escape from immune surveillance and promote metastasis.

      Methods:
      GFP-luciferase tagged human lung adenocarcinoma cell line, H2122-GL, was further transfected with KIR2DL1 (LL454) plasmids. Stable transformants were enriched by cell sorting. In vivo experimental metastasis were performed in both athymic nude mice and in Nbeal2 knockout and wild type C57 black mice, by tail vein injections of H2122 parental and KIR expressing cells, with and without pre-infusion of human platelets. Levels of tumor cells detected in the lung and other sites were closely monitored by bioluminescence imaging at various time intervals, using an IVIS200 imager.

      Results:
      24 hours after tail vein injection of a million parental H2122-GL, as low as 0.4 million photons were detectable in the lungs of nude mice (n=5), while those mice injected with a same number of H2122-GL-KIR2DL1 cells, they produced 1.85 million photons in the lungs, showing a 4.6 fold increase in accumulation of KIR-expressed cancer cells than those parental cells in the lung. When the nude mice were pre-infused with iv injection of human platelets followed by tail vein injection of parental or KIR-expressed H2122 cells, enhancement up to 7 fold of lung metastases of KIR expressed H2122 were detected relative to the parental cells as early as 24 hours. 5 weeks post injection, an enhancement up to 190 fold in bioluminescence intensity was found with KIR expressed cells relative to the parental cells. Interestingly, the enhancement of lung metastases was abrogated when similar experiments were repeated in the NBeal2 knockout mice, whose platelets were nonfunctional due to defective alpha-granules and deficiency in their cargo, including von Willebrand factor, thrombospondin-1, and platelet factor 4. One hour after tail vein injection, both parental and KIR expressed H2122 cells produced same but low number of lung metastases, indicating that the defective platelets in the ko mice had failed to promote lung metastases. In the wild type mice, significantly more KIR expressed H2122 cells were detected in the lung relative to parental cells. However, as expected, these early lung metastases were rejected later by the host intact immune cells.

      Conclusion:
      Our studies demonstrated that metastatic cancer cells acquire immune-resistance by aberrantly express Natural Killer-Cell Immunoglobulin-like Receptors (KIRs) on their surface and that KIR-expressing cancer cells interact more strongly with platelets leading to significantly increase in NK tolerance and enhancing cancer metastases in pre-clinical models.

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      ORAL41.03 - Myeloid Derived Supressor Cells and Their Clinical Relevance in Non-Small Cell Lung Cancer (ID 2946)

      O. Arrieta Rodriguez, R. Morales-Flores, A. Garcia-Vicente, E. Montes-Servín, F. Salinas-Parra, L. Barrera

      • Abstract
      • Presentation
      • Slides

      Background:
      Lung cancer is the leading cause of cancer death worldwide and most of the patients are diagnosed with advanced disease. Myeloid-derived suppressor cells (MDSCs) are major contributors to tumor immune tolerance and targeting them can improve antitumor activity.

      Methods:
      We investigated the CD33[+]CD11b[+]CD66b[+]CD15[+]VEGFR-1[hi] MDSCs frequency in 120 non-small cell lung cancer (NSCLC) treatment-naive patients, with stage IIIB and IV of disease. We analyzed 1-year survival and its prognostic significance in relation to outcome analysis as well as its potential immunosuppression over cytotoxic CD8[+] T lymphocytes. The immunophenotyping of cell population was performed with multiparametric technique by flow cytometry.

      Results:
      We found a significant increase compared with controls in: Percentage of CD33[+]CD14[-]CD11b[+]CD66b[+]CD15[+ ](10.4 ± 5.01% vs. 3.1 ± 1.7% P<0.0001); Mean Fluorescence intensity (MFI) of VEGFR on MDSCs (P<0.001); plasma levels of arginase-1 (P<0.01); arginase-1 enzymatic activity (P<0.05); plasma levels of TGF-β (P<0.0001), IL-10 (P=0.0027) and IL-6 (P<0.0001). On the other hand, we found a significant decrease compared with controls in: Plasma levels of IFN-γ (P<0.0001); CD8[+] T cells (P<0.001); CD8[+]T cells IFN-γ production co-cultured with MDSCs (N=10; P<0.001) and MFI of CD3ζ chain (N=10; P<0.05). The percentage of MDSCs was negatively related to the percentage of CD8[+] T cells in the peripheral blood (N=155, R=-0.3045, P=0.0167). Finally, we found an inverse correlation between circulating MDSCs percentages and overall survival (P=0.09).

      Conclusion:
      Our study provides evidence of an increased pool of CD33+CD11b+CD66b+CD15+VEGFR-1hi MDSCs in the peripheral blood of NSCLC patients. The suppressive effect, of MDSCs on CD8+ T lymphocytes, suggests an important role in mediating immunosuppression in NSCLC that should enable the development of a novel biomarker and thus might represent a potential target for therapeutic intervention.

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      ORAL41.04 - Discussant for ORAL41.01, ORAL41.02, ORAL41.03 (ID 3439)

      N.A. Rizvi

      • Abstract
      • Presentation

      Abstract not provided

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      ORAL41.05 - Targeting Phosphatidylserine-Mediated Immune Suppression Enhances the Efficacy of Immune Checkpoint Blockade in Pre-Clinical Tumor Models (ID 1011)

      R.A. Brekken, B. Freimark, J. Gong, C. Baldwin, V. Nguyen, M. Gray, S. Yin, J. Hutchins, A. Schroit, X. Huang

      • Abstract
      • Presentation
      • Slides

      Background:
      Despite substantial progress, only a subset of cancer patients benefit from blockade of the PD-1 immune checkpoint. Multifocal immune suppression in the tumor microenvironment is the underlying cause for the limited efficacy of immune checkpoint blockade. Persistent immune suppression prevents the development of a robust T cell response to tumor specific antigens that is required for effective downstream immune checkpoint blockade. An underappreciated but significant contributor to immune suppression in tumors is the expression of the membrane phospholipid phosphatidylserine (PS) on the surface of tumor cells and tumor-derived microvesicles. PS is recognized by receptors on immune cells where it triggers the secretion of immune suppressive cytokines, prevents the differentiation of myeloid-derived suppressor cells (MDSCs) and inhibits dendritic cell (DC) maturation; events that prevent a productive anti-tumor T cell response. Bavituximab, a chimeric monoclonal antibody that targets PS and inhibits PS-mediated immunosuppressive signaling, drives immune activation by reducing the levels of MDSCs, by polarizing tumor-associated macrophages towards an M1 phenotype and by promoting the maturation of dendritic cells (DCs).

      Methods:
      The efficacy of bavituximab, anti-PD-1 and combination therapy was evaluated in multiple syngeneic, pre-clinical tumor models. Treatment efficacy was determined by inhibition of tumor growth and by immunophenotyping of spleen and tumor infiltrating leukocytes.

      Results:
      The combination of antibody-mediated PS and PD-1 blockade was significantly more effective in reducing tumor burden and promoting immune activation than single agent therapy. Combination therapy increased tumor infiltration of effector T-cells (Teff), increased the Teff:T regulatory cell ratio in the tumor and enhanced Teff function as determined by IFN-γ, TNFα and granzyme B levels associated with Teff cells in the spleen and tumor. Furthermore combined blockade of PS and PD-1 signaling reduced the level of immune suppressive cells (e.g., MDSCs, M2 macrophages, and Treg) in the tumor microenvironment.

      Conclusion:
      These results raise the possibility that PS blockade with bavituximab can enhance the efficacy of anti-PD-1 therapy even in patients with tumors that are unresponsive to single agent immune checkpoint therapy.

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      ORAL41.06 - Transcriptional Profiling of Distinct Macrophage Subsets in Lung Tumor Microenvironment Reveals Their Functional Heterogeneity (ID 3181)

      J.M. Poczobutt, S. De, V. Yadav, H. Li, J. Kwak, T. Sippel, D. Hanson, T.T. Nguyen, M.C. Weiser-Evans, R. Nemenoff

      • Abstract
      • Slides

      Background:
      Lung cancer is the leading cause of cancer-related deaths in both men and women. While extensive research has focused on genetic mutations in neoplastic epithelial cells, it has now become apparent that cancer progression and metastasis involve complex interactions between cancer cells and the cells of the tumor microenvironment. Myeloid cells of mononuclear phagocyte lineage are a significant component of the tumor microenvironment in lung cancer. Depending on the activation state, myeloid cells have been implicated in tumor – promoting processes such angiogenesis, tissue remodeling and immunosuppression, but also in anti-tumor immunity such as supporting immune surveillance and direct cytotoxicity. The goal of this study was to identify distinct populations of monocyte/macrophage cells and to gain insight into their functions through transcriptional profiling.

      Methods:
      We used an orthotopic immunocompetent mouse model, in which Lewis Lung carcinoma cells, a cell line derived from mouse adenocarcinoma, were injected directly into the left lung lobe of syngeneic C57BL/6 mice. Whole left lung lobes bearing primary tumors were harvested at 2 and at 3 weeks after cancer cell injection, together with lungs from uninjected mice. Tissues were processed into single-cell suspensions and analyzed by multi-color flow cytometry. The flow cytometry strategy employed a combination of myeloid specific surface markers such as CD11b, CD11c, CD64, and SiglecF to identify distinct monocyte/macrophage subpopulations. We recovered these cell populations by flow cytometry-based cell sorting, isolated RNA, and performed transcriptional profiling by RNA-seq. Sequencing data were analyzed by TopHat/Cufflinks/CuffDiff software package and EdgeR. To define the lineage of the isolated cells we correlated their transcriptional profiles to published profiles of immune cells from blood and lung of naïve mice. Further, we used hierarchical clustering and web-based bioinformatic pathway analysis tool to discover functions and pathways enriched in specific myeloid populations.

      Results:
      Based on the combination of myeloid markers and transcriptional profiling, we identified 4 distinct populations of monocyte/macrophage cells: MacA, which represent alveolar macrophages, MacB1, which represent a mixture of dendritic cells and Ly6C- monocytes, MacB2, which represent Ly6C+ monocytes, and MacB3, which represent interstitial/infiltrating macrophages. While the numbers of MacA and MacB1 remain unchanged with cancer progression, MacB2 and MacB3 expand rapidly. Pathway analysis indicated that each population of cells regulates distinct functions in the tumor microenvironment, such as lipid metabolism, cytokine or chemokine secretion, production and remodeling of extracellular matrix, antigen presentation.

      Conclusion:
      These data provide critical insights into the heterogeneous nature and diverse functions of myeloid cells in tumor microenvironment of lung cancer. This study has the potential for development of therapeutics that target specific subsets of myeloid cells that could complement conventional cancer-cell-targeted therapies.

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      ORAL41.07 - The Identification of Therapeutic Targets in Lung Cancer Based on Transcriptomic and Proteomic Characterization of Cancer-Testis Antigens (ID 1555)

      D. Djureinovic, B. Hallström, J.S.M. Mattsson, L. La Fleur, J. Botling, L. Fagerberg, H. Brunnström, S. Ekman, E. Ståhle, H. Koyi, M. Lambe, C. Lindskog, E. Branden, F. Pontén, M. Uhlén, P. Micke

      • Abstract
      • Presentation
      • Slides

      Background:
      Most immunotherapeutic modalities are based on the concept that the immune system can attack targets that are specifically expressed in cancer cells. Cancer testis antigens (CTAs) are a group of genes with a broad expression in cancers including non-small cell lung cancer (NSCLC). In normal tissues the expression of CTAs is restricted to immune privileged organs such as testis and placenta. This limited expression in somatic tissues renders CTAs as a valuable group of genes for the exploration of potential immunotherapeutic targets. The aim of this study was to comprehensively explore the CTA repertoire in NSCLC and to try identifying new CTAs.

      Methods:
      RNA sequencing (RNAseq) was performed on 202 NSCLC samples from a consecutive clinical cohort of surgically resected patients. For the analysis of the comprehensive CTA expression profile in NSCLC we used Cancer Testis (CT) Database containing all genes reported as CTAs in the literature. The NSCLC transcriptome was compared to the normal transcriptome comprising of 22 paired normal lung tissues as well as to 122 samples from 32 different normal human tissues. Corresponding protein expression was evaluated by using immunohistochemistry (IHC) on tissue microarrays (TMAs) containing tumor tissue from the same patients as used in the RNA sequencing.

      Results:
      Of the 276 established CTAs, 155 genes (56%) were restricted to testis and placenta among normal tissues and were identified as CTAs. One third (35%) was expressed in at least one of the 202 individual NSCLC cases and 28 of these genes were previously not reported to be expressed as CTAs in NSCLC. Applying stringent analysis criteria on our RNA sequencing data set we identified 61 genes that were expressed in NSCLC and testis or placenta, but not in other normal tissues. Thus, these genes present potential new CTAs. The specific cancer/testis expression of selected genes (ZNF560, TGIF2LX, TFPI2, HMGB3, TKTL1 and STK31) from this group was confirmed on protein level using IHC. Additional analysis revealed that most CTAs were concurrently expressed in adenocarcinoma and squamous cell carcinoma. The expression of a subset of genes was histology dependent, with predominant expression in adenocarcinoma (e.g. XAGE family members) and in squamous cell carcinoma (e.g. MAGE family members).

      Conclusion:
      Our study provides deep sequencing mRNA expression profiles of the whole CTA repertoire in NSCLC. Several CTAs previously identified in other cancers but not analyzed in NSCLC have been identified on both mRNA and protein level. Additionally, we have identified 61 novel genes as CTAs in NSCLC that previously have not been reported as CTAs and several of these were also confirmed on protein level. This data offers the opportunity to design individual therapy options to target single CTAs or CTA clusters.

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      ORAL41.08 - Discussant for ORAL41.05, ORAL41.06, ORAL41.07 (ID 3440)

      R. Herbst

      • Abstract
      • Presentation

      Abstract not provided

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    OA02 - Novel Targets and Biomarkers in Malignant Pleural Mesothelioma (ID 369)

    • Event: WCLC 2016
    • Type: Oral Session
    • Track: Mesothelioma/Thymic Malignancies/Esophageal Cancer/Other Thoracic Malignancies
    • Presentations: 8
    • Now Available
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      OA02.01 - The microRNA-15/16 Family Regulates Tumour Cell Growth via Fibroblast Growth Factor Signals in Malignant Pleural Mesothelioma (Now Available) (ID 5395)

      K. Schelch, M.B. Kirschner, M. Williams, R. Lin, Y.Y. Cheng, M. Grusch, W. Berger, N. Van Zandwijk, G. Reid

      • Abstract
      • Presentation
      • Slides

      Background:
      Malignant pleural mesothelioma (MPM) is a highly aggressive, asbestos-related malignancy characterized by poor outcome and limited therapeutic options. Fibroblast growth factor (FGF) signals play important roles in mesothelioma cell growth and malignant behavior and their inhibition leads to reduced tumor growth. MicroRNAs (miRNAs) are conserved noncoding RNAs controlling gene expression via translational repression of target mRNAs. The miR-15/16 family is downregulated in MPM and has tumor suppressor functions. Several FGFs/FGFRs are predicted miR-15/16 targets. The aim of this study was to explore the link between the miR-15/16 and the FGF/R family in MPM.

      Methods:
      Gene and microRNA expression was determined by RT-qPCR or Taqman Low Density Arrays (TLDAs). Mimics were used for restoring microRNA expression. Stimulation or inhibition of FGF signals or bcl-2 was achieved by recombinant FGF2, siRNAs, or small-molecule inhibitors, respectively. A SYBR green-based proliferation assay and colony formation assays were used to monitor effects on cell growth.

      Results:
      Expression analysis showed a consistent downregulation of target FGF/FGFR genes after transfection with miRNA mimics. Restoration of miR-15/16 led to dose-dependent growth inhibition, which significantly correlated with sensitivity to the specific FGFR1 inhibitor PD166866. Re-expression of microRNAs in combination with FGFR knock-down or pharmacological inhibition resulted in reduced activity, indicating target competition. Combined inhibition of the FGF-axis and bcl-2, another established target of miR-15/16, resulted in enhanced activity. Treatment with recombinant FGF2 further reduced mature as well as pri-microRNA levels and also could prevent/reduce growth inhibition by mimics, but only when added within 24 hours after transfection. TLDA screens after stimulation/inhibition of FGF signals identified regulation of several other miRNAs involved in pathways relevant for tumour growth and aggressiveness.

      Conclusion:
      Our data shows that the post-transcriptional repression of FGF-mediated signals contributes to the tumour-suppressor function of the microRNA-15/16 family. Impairing hyperactivated FGF signals as well as the anti-apoptotic protein bcl-2 through the restoration of this miRNA family might serve as a novel therapeutic strategy in mesothelioma.

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      OA02.02 - Gremlin-1 is a Key Regulator of the Invasive Phenotype in Mesothelioma (Now Available) (ID 5424)

      M. Yin, M. Tissari, J. Tamminen, I. Ylivinkka, M. Ronty, K. Lehti, M. Hyytiainen, M. Myllarniemi, K. Koli

      • Abstract
      • Presentation
      • Slides

      Background:
      Malignant mesothelioma is an aggressive cancer that develops from mesothelial cells, most often in the pleural lining of the lung. We have previously shown that the BMP inhibitor protein gremlin-1 is highly expressed in mesothelioma and induces a mesenchymal and chemoresistant phenotype in mesothelioma cells. Since mesothelioma tumors are locally highly invasive, we analyzed the role of gremlin-1 in mesothelioma cell migration and invasive growth.

      Methods:
      Primary mesothelioma cells isolated from patient pleural fluid as well as mesothelioma cell lines were used for in vitro studies. Cells were transfected with siRNAs or transduced with lentiviral expression vectors. Invasive growth was analyzed in 3D matrigel or collagen I matrices. mRNA expression was analyzed using a commercial PCR array and quantitative RT-PCR. Migration assays were performed using scratch wound assay or Transwell migration assay with fibronectin or collagen coating. TGF-β and BMP signaling activity was measured with reporter-luciferase assays. For in vivo mouse xenograft experiment cells were additionally transduced to express a luciferase marker. Subcutaneous cell injection with matrigel matrix was performed in the flank of nude mice.

      Results:
      Mesothelioma cells expressing gremlin-1 showed invasive sprouting when tumor cell spheroids were imbedded into 3D collagen matrix. Silencing of gremlin-1 expression significantly reduced invasive growth. In addition, cells overexpressing gremlin-1 gained invasive growth ability. This was associated with increased mRNA expression levels of Slug and matrix metalloproteinases (MMP) as well as reduced expression of E-cadherin. The cells were more migratory and exhibited increased expression of certain integrins, especially the α~v~ subunit. Gremlin-1 induced invasive growth was dependent on MMP activity and associated with increased TGF-β activity. Intrapleural injection of gremlin-1 overexpressing mesothelioma cells isolated from a patient with epithelioid mesothelioma, produced tumors in 2/4 mice over 4 months after injection. Cells transduced with vector only did not produced tumors (0/4). When cells were injected subcutaneously together with matrigel gremlin-1 overexpressing tumors appeared more slowly, but exhibited comparable luciferase signal 2.5 months after injection. However, gremlin-1 tumors showed more local spreading and in contrast to control tumors some also developed metastasis (2/6 mice).

      Conclusion:
      Mesothelioma invades locally and has poor prognosis. We have identified gremlin-1 as an important regulator of mesothelioma chemoresistance and invasive growth behavior. Blocking gremlin function may overcome drug resistance and reduce invasion of mesothelioma.

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      OA02.03 - Circulating Fibroblast Growth Factor 18 is Elevated in Malignant Pleural Mesothelioma Patients - A Multi-Institutional Study (Now Available) (ID 5988)

      Y. Dong, H. Zhang, K. Schelch, T. Klikovits, P. Stockhammer, M. Jakopovic, M. Samarzija, L. Brcic, G. Reid, M.B. Kirschner, S. Kao, I. Opitz, W. Weder, T. Frauenfelder, T.D.L. Nguyen-Kim, W. Klepetko, N. Van Zandwijk, B. Hegedus, W. Berger, B. Dome, V. Laszlo, M. Grusch, M.A. Hoda

      • Abstract
      • Presentation
      • Slides

      Background:
      Malignant pleural mesothelioma (MPM) is a rare but devastating malignancy. Despite the search for new promising treatment approaches, the outcome for most MPM patients remains dismal. Therefore, the identification of novel biomarkers is urgently needed in order to identify patients with a better prognosis and to support personalized therapeutic decisions. In our previously published study, we were able to show that fibroblast growth factor 18 (FGF18) is overexpressed in MPM tissue specimens and cell models. The objective of this study was the evaluation of FGF18 as a circulating biomarker in MPM.

      Methods:
      Plasma was collected from 107 MPM patients at the time of diagnosis or before surgical resection. Samples were included from the Medical University of Vienna, University Hospital Center in Zagreb and from The Concord Repatriation General Hospital and Strathfield Private Hospital in Sydney. Samples from 49 healthy volunteers and from 8 patients with non-malignant pleural diseases served as controls. Circulating FGF18 was measured by enzyme-linked immunosorbent assay and correlated to clinical, pathologic and radiologic parameters.

      Results:
      Plasma FGF18 level was significantly elevated in MPM patients vs. healthy controls (P<0.0001). A slight increase of circulating FGF18 level was also detected in patients with pleuritis or fibrosis (vs. control, P=0.0067). Sarcomatoid (n=7) morphology was associated with high FGF18 levels when compared to the epithelioid (n=77) histology (P=0.0064). Importantly, MPM patients presenting with FGF18 levels below the median had a significantly longer overall survival when compared to those with high FGF18 levels (median survival 625 versus 382 d, P=0.0038). Data on multivariate analysis, disease-free survival, correlation with other biomarkers and tumor volume will be presented at the conference.

      Conclusion:
      Our findings reveal that FGF18 is a promising blood-derived candidate biomarker in MPM. Furthermore FGF18 may support the histological classification of MPM and the identification of MPM patients with poor prognosis. .

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      OA02.04 - Discussant for OA02.01, OA02.02, OA02.03 (Now Available) (ID 6952)

      M.B. Kirschner

      • Abstract
      • Presentation
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      Abstract not provided

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      OA02.05 - Expression of miR-223 in Mesothelioma Xenografts Originates from Stromal Cells in the Tumour Microenvironment (Now Available) (ID 5875)

      K.H. Sarun, Y.Y. Cheng, M.B. Kirschner, N. Van Zandwijk, R. Lin, G. Reid

      • Abstract
      • Presentation
      • Slides

      Background:
      Malignant pleural mesothelioma (MPM) is an aggressive cancer caused by asbestos exposure with limited therapeutic options. Dysregulated microRNAs play an important role in MPM biology and candidate microRNAs have been investigated as diagnostic and prognostic biomarkers or as a potential treatment targets. The role of miR-223 has previously been investigated in MPM tumour cells and was shown to act as a tumour suppressor by regulating cell mobility. Previous research indicated miR-223 to be primarily expressed by myeloid progenitor derived cells during differentiation of granulocytes and monocytes. This suggests miR-223 might have a more significant role in the inflammatory response during tumourigenesis. In this study we aimed to investigate the origin of miR-223 using mesothelioma xenograft and syngraft models.

      Methods:
      Human and mouse mesothelioma cell line-derived xenograft (MSTO-H211 and H226) and syngraft (AB1) models were established. MicroRNA profiles of xenografts were compared against profiles of their corresponding in vitro cultured cells to determine candidates. RT-qPCR using TaqMan MicroRNA assays was used to validate expression levels of miR-143-3p, miR-214-3p and miR-223-3p in tumour xenografts and syngrafts with those in corresponding cell lines in vitro. Species-specific ddPCR analysis was performed on RNA from xenograft tumours to determine the expression of human and mouse pri-miR-223.

      Results:
      MicroRNA profiles of xenograft tumours showed significant upregulation (p < 0.05) of miR-143-3p, miR-214-3p and miR-223-3p compared to corresponding in vitro mesothelioma cell lines. Only miR-223 showed significant upregulation in both xenograft and syngraft tumours compared to corresponding in vitro mesothelioma cell lines (>10000-fold increase). Other microRNAs were not significantly different between cell lines and tumours. RNA isolated from xenograft tumours contained significantly more mouse pri-miR-223 than human pri-miR-223 (p < 0.001), with only minimal expression levels of human tumour pri-miR-223 within xenograft tumours.

      Conclusion:
      Mature miR-223 is significantly overexpressed in xenograft tumours compared to corresponding in vitro mesothelioma cell lines suggesting stromal contribution. Species-specific pri-miRNA confirmed miR-223 is almost exclusively expressed by the mouse stromal cells in xenograft tumours. Ultimately, localising the expression of miR-223 to specific cell types (such as myeloid derived cells) through in situ hybridisation should help identify a more biologically relevant role for miR-223 in the tumour microenvironment.

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      OA02.06 - Converting Tumor-Mediated PD-L1 Inhibition into CAR T-Cell Costimulation to Potentiate Thoracic Cancers Immunotherapy (Now Available) (ID 6058)

      A. Morello, N. Chen, L. Cherkassky, M. Sadelain, D. Jones, P.S. Adusumilli

      • Abstract
      • Presentation
      • Slides

      Background:
      To overcome tumor-mediated inhibition of chimeric antigen receptor (CAR) T cells, we herein investigated the impact of tumor PD-L1 upregulation on CAR T-cell exhaustion and anti-tumor efficacy, and further developed clinically translatable T-cell extrinsic as well as intrinsic strategies to overcome PD-L1 inhibition in models of lung cancer (LC) and malignant pleural mesothelioma (MPM).

      Methods:
      Human T cells were transduced with MSLN-specific CAR with CD28 and CD3zeta domains (M28z) were tested in vitro and in clinically-relevant LC and MPM mouse models by bioluminescence imaging, BLI of tumor burden progression. To counteract PD-1/PD-L1 inhibition in vivo, we evaluated the efficacy of PD-1 blocking antibody or cell-intrinsic genetic-engineering strategies by cotranducing M28z CAR T cells with a PD-1 dominant negative receptor (PD1-DNR) or with PD-1/4-1BB fusion protein.

      Results:
      A single, low-dose of M28z CAR T cells is able to resist the progression of established tumor for 40 days, but mice eventually died with progressing tumor. Tumor harvest analysis demonstrated the PD-1 and PD-L1 upregulation on CAR T cells and tumor cells (Figure panel A). We then confirmed in vitro that PD-L1 inhibits M28z T-cell effector functions (proliferation, cytotoxicity and cytokine secretion). The addition of PD-1 blocking potentiates CAR T-cell therapy in vivo but its efficacy requires multiple injections (Panel B). In contrast, a single dose of M28z T cells coexpressing PD1-DNR restore effector functions, enhance tumor burden control (Panel C) and prolong median survival (56 vs 82 days, p=0.001). Converting PD-L1 inhibition into a positive costimulatory signal by PD-1/4-1BB construct cotransduction into M28z CAR T cells enhanced cytokine secretion and T-cell accumulation (Panel D). Figure 1



      Conclusion:
      Our results demonstrate the therapeutic benefit of providing optimal costimulation and coinhibitory blockade to counteract PD-L1/PD-1 immunosuppression, thus potentiate CAR T-cell therapy for lung cancer and mesothelioma.

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      OA02.07 - Characterization of the Tumor Microenvironment and Investigation of Immune Checkpoint Expression in Malignant Pleural Mesothelioma (Now Available) (ID 4437)

      E. Marcq, V. Siozopoulou, J. De Waele, J. Van Audenaerde, K. Zwaenepoel, E. Santermans, N. Hens, P. Pauwels, J.P. Van Meerbeeck, E. Smits

      • Abstract
      • Presentation
      • Slides

      Background:
      Malignant pleural mesothelioma (MPM) is an aggressive cancer with a poor prognosis and an increasing incidence, for which novel therapeutic strategies are urgently required. Since the immune system has been described to play a role in protection against MPM, characterization of its tumor immune microenvironment (TME) and immune checkpoints might help to identify new immunotherapeutic targets and their predictive and/or prognostic value.

      Methods:
      Immunohistochemistry (IHC) was performed on tissue samples of untreated (n=40) and chemotherapy-pretreated (n=14) MPM patients. Different subsets if immune cells were identified based on staining for CD4, CD8, FoxP3, CD68, CD45RO and granzyme B. The expression of the immune checkpoints TIM-3, LAG-3, PD-1 and its ligand PD-L1 was also investigated. The relationship between the immunological parameters and survival, as well as response to chemotherapy was analyzed using the R statistical software.

      Results:
      All patients had CD8+ tumor infiltrating lymphocytes (TILs), CD68+ histiocytes and macrophages and CD45RO+ T cells in their stroma, with CD8+ TILs being the predominant cell type of the immune infiltrate. Stromal CD4+ TILs were found in 75% of the untreated and 71% of the pretreated samples. A subset of those cells was also FoxP3+ and these CD4+FoxP3+ cells were positively correlated with stromal CD4 expression (p<0.001). Less than half of the samples showed positivity for granzyme B. Both, untreated and pretreated patients had PD-1+ TILs, while only 10% of the untreated patients also had PD-1+ tumor cells. PD-L1 positivity on lymphocytes and/or tumor cells was observed for more than half of the patients, with significant differences according to the histological subtype (p<0.001). Patients with a sarcomatoid histology showed the most PD-1 expression. TIM-3 was expressed in tumor cells, stromal lymphocytes and plasma cells, less often in pretreated samples compared to untreated samples. All samples were negative for LAG-3. After multivariate analysis stromal CD45RO expression was found to be an independent negative predictive factor for response to chemotherapy (p=0.017) and expression of CD4 and TIM-3 in lymphoid aggregates were good prognostic factors (p=0.008; p=0.001).

      Conclusion:
      Our data reveal the diversity of immune cells present in MPM and point to TIM-3 as a new target in mesothelioma. Administering chemotherapy before or together with PD-1/PD-L1/TIM-3 blocking agents may not be the best combination sequence and further research on the predictive value of CD45RO in the stroma might guide patient selection for chemotherapy.

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      OA02.08 - Discussant for OA02.05, OA02.06, OA02.07 (Now Available) (ID 6964)

      M. Grusch

      • Abstract
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      Abstract not provided

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