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Eloisa Jantus-Lewintre

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    MA17 - Molecular Mechanisms and Therapies (ID 143)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Biology
    • Presentations: 12
    • Now Available
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      MA17.01 - Cell Lineage and Chromatin Landscape of Lung Cancer Are Controlled by GATA6 (Now Available) (ID 59)

      15:45 - 17:15  |  Presenting Author(s): Anna Arnal Estapé  |  Author(s): Wesley L. Cai, Alexandra E. Albert, Francesc López-Giráldez, Minghui Zhao, Laura E. Stevens, Kiran D. Patel, Don X. Nguyen

      • Abstract
      • Presentation
      • Slides

      Background

      Thoracic malignancies are histologically and biologically heterogeneous. The underlying causes of this heterogeneity are believed to be linked to the complex cellular ontogenies of lung cancers and their relationship to pulmonary development. Lineage selective transcription factors (TFs) are critical determinants of airway cell differentiation and homeostasis, but their biological requirements are often conditional. Analogously, several developmental TFs can paradoxically enhance or inhibit lung cancer progression, depending on cellular and epigenetic contexts which remain largely undefined. In this study, we report a novel function for the endodermal and pulmonary specifying TF GATA6 in lung cancer.

      Method

      To understand the role of GATA6 in lung tumorigenesis we used a genetically engineer mouse model (GEMMs) harboring Kras p53 mutations using progenitor cell specific gene targeting. We combined GEMMs biology with integrated analysis of the transcriptome and the chromatin landscape of lung cells derived from GATA6 deficient tumors.

      Result

      In this study, we uncover a conditional role for the endodermal and pulmonary specifying TF GATA6 during the initiation and progression of Kras mutant lung adenocarcinoma (LUAD). Inhibition of Gata6 in genetically engineered mouse models dampens the proliferation and increases the differentiation of LUAD tumors. These effects are influenced by the epithelial cell type that is targeted for transformation, demonstrating that GATA6 expression is an important molecular determinant of the cell of origin in Kras mutant lung cancer. In LUAD cells derived from surfactant protein C expressing progenitors, we identify multiple genomic loci that are bound by GATA6. Moreover, suppression of Gata6 in these cells significantly alters chromatin accessibility, particularly at distal enhancer elements. Analogous to its paradoxical activity in the developing lungs, GATA6 expression fluctuates during different stages of LUAD progression and can epigenetically control diverse lineage programs associated with cell proliferation, alveolar specification, BMP signaling, and epithelial plasticity.

      In summary:

      1) GATA6 expression varies during different stages of disease progression in the lung adenocarcinoma (LUAD) subtype

      2) Suppression of Gata6 can diminish the proliferation and progression of LUAD in a manner that is influenced by the transforming progenitor of origin

      3) GATA6 differentially modulates chromatin accessibility across the genome of LUAD cells

      4) This epigenomic mechanism results in the activation of different lineage specific programs, including the BMP signaling pathway.

      Conclusion

      These findings reveal how GATA6 can modulate the chromatin landscape of lung cancer cells to control their divergent lineage dependencies during tumor progression.

      D.X.N. has received research funding from AstraZeneca, Inc.

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      MA17.02 - Identify Vulnerable Pathways and Improve Treatment Outcomes in LKB1-Deficient Lung Tumors (Now Available) (ID 2067)

      15:45 - 17:15  |  Presenting Author(s): Meng Xu Welliver  |  Author(s): Feng Jin, Joseph M Amann, Michael Koenig, Xiaokui Mo, David P Carbone

      • Abstract
      • Presentation
      • Slides

      Background

      The LKB1 tumor suppressor is inactivated in about 20% of non-small cell lung cancers (NSCLC) by mutations. Cancer cells with LKB1 deficiency exert complex effects on signal transduction and transcriptional regulation, which may cause these cells more susceptible to certain therapies comparing to cells with intact LKB1 function. Phenformin, an antidiabetic medicine from the biguanides class, has shown activities against NSCLC. Phenformin as a single agent has been shown to reduce tumor burden and prolonged survival in Kras;Lkb1 compound mutant mice but not Kras;p53 mice, suggesting specific activities in tumor with LKB1 deficiency. Currently patients with unresectable locally advanced NSCLC are treated standardly with concurrent chemoradiotherapy followed by checkpoint inhibitor, durvalumab. In this project, we test treatment sensitivity to radiotherapy and/or phenformin in lung cancer cells with intact or deficient LKB1.

      Method

      Human lung cancer cell lines described below were used in (1) clonogenic survival assays as well as (2) generating tumor xenograft on nude mice for tumor growth delay experiments. A549, HCC15 and Calu-1 cell lines obtained from ATCC were cultured in RPMI1640 containing 5% FBS, without antibiotics. A549 cells (LKB1 deficient, TP53 WT and KRAS mutated) or HCC15 (LKB1 deficient, TP53 mutated and KRAS WT) were transfected with empty vector or WT LKB1 or LKB1-K78I plasmids; Calu-1 (LKB1 WT, KRAS mutated and p53 deleted) transfected with empty vector or LKB1 CRIPR KO were generated as described previously.

      Result

      A549 cells with transfected WT-LKB1 were significantly more resistant to ionizing radiation (IR) induced cell kill (8.7% survival at 8 Gy) comparing to cells transfected with empty vector (3.7%) or kinase-dead LKB1 genes (4.2%). Similarly, HCC15 cells with transfected WT-LKB1 are significantly more resistant to IR induced cell kill (7.5%) comparing to cells transfected with empty vector (4.1%) or kinase-dead LKB1 genes (3.4%). Calu-1 cells harbor WT LKB1, and it is significantly more resistant to IR induced cell kill (8.3%) comparing to their counterpart with LKB1 KO (Calu-1 transfected with LKB1 CRIPR KO) (4.1%). When A549 cells were pretreated with 30 μM phenformin prior to, during and after IR, there was no change in survival in cells transfected with WT LKB1; however there was significant further reduction in survival in cells transfected with empty vector (LKB1 deficient). Xenograft tumors were generated in nude mice with A549 cells with the above genetic alterations. There was significant further tumor growth delay in those with A549 with deficient LKB1 comparing to those with A549 with WT LKB1 gene add-back. This tumor growth delay was further enhanced when these mice were treated with oral phenformin prior to, during and after IR treatment, confirming the in vitro experimental results.

      Conclusion

      Human lung cancer with deficient LKB1 are more sensitive to ionizing radiation in vitro and in vivo. This was regardless of the TP53 or KRAS mutation status. A549 cells with deficient LKB1 were also more sensitive to phenformin treatment. Phenformin treatment further sensitized LKB1 deficient lung cancer cells to IR. This suggested that LKB1 can serve as a predictive biomarker to triage patient treatments.

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      MA17.03 - Importance of Cullin4 Ubiquitin Ligase in Malignant Pleural Mesothelioma (Now Available) (ID 2349)

      15:45 - 17:15  |  Presenting Author(s): Mayura Meerang  |  Author(s): Jessica Kreienbühl, Vanessa Orlowski, Michaela B Kirschner, Walter Weder, Isabelle Opitz

      • Abstract
      • Presentation
      • Slides

      Background

      Loss of the tumor suppressor NF2 is frequent in malignant pleural mesothelioma (MPM). NF2 suppresses tumorigenesis in part by inhibiting Cullin4 ubiquitin ligase (CUL4) complex. Here we aimed to evaluate an importance of CUL4 in MPM.

      Method

      We evaluated the expression of CUL4A and CUL4B in tissue microarrays using immunohistochemistry. We tested the efficacy of cullin inhibition by pevonedistat, a small molecule inhibiting cullin neddylation, in 13 cell lines and 3 primary cells in 2D and 3D culture. Four groups of SCID mice haboring intraperitoneal (ip.) pevonedistat sensitive (MSTO211H) or resistant (ACC-Meso1) cell lines were treated with pevonedistat (50 mg/kg; ip.) on a 5day on/5day off schedule for 3 cycles. Treatment efficacy was assessed by means of overall survival.

      Result

      CUL4B expression was associated with clinical outcomes (figure 1). Five MPM cell lines (38%) were highly sensitive to pevonedistat (IC50<500 nM). This remained true in 3D spheroid culture. The treatment induced S/G2 cell cycle arrest and accumulation of cells undergoing DNA re-replication (containing >4N DNA content) known to be mediated by p21 and CDT1 accumulation. Indeed the accumulation of p21 and CDT1 was more pronounced in pevonedistat sensitive cell lines after the treatment. Two of primary cells (67%) were sensitive to pevonedistat and also showed higher CDT1 accumulation following the treatment compared to the resistant cells. In vivo, pevonedistat treatment significantly prolonged survival of mice bearing both sensitive and resistant MPM tumors. Pevonedistat treatment reduced growth (phosphorylated histoneH3 positive) in pevonedistat sensitive tumor but increased apoptosis (cleaved–caspase3 positive) in pevonedistat resistant tumor.

      fig1 wclc2019.jpg

      Conclusion

      High CUL4B expression may play a role in MPM progression. Inhibition of cullins by pevonedistat induced growth arrest and DNA re-replication strongly in a subset of MPM. The major mechanism seems to be mediated by p21 and CDT1 accumulation in vitro. Investigation of mechanisms in vivo is ongoing.

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      MA17.04 - Discussant - MA17.01, MA17.02, MA17.03 (Now Available) (ID 3786)

      15:45 - 17:15  |  Presenting Author(s): Julian Carretero

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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      MA17.05 - DNA-Binding and Gene Expression Profiles in Max Deficient Small Cell Lung Cancer (Now Available) (ID 377)

      15:45 - 17:15  |  Presenting Author(s): Paula Llabata  |  Author(s): Manuel Torres-Diz, Antonio Gomez, Montse Sanchez-Cespedes

      • Abstract
      • Presentation
      • Slides

      Background

      The MYC pathway is frequently altered in cancer, mostly by gene activation of the MYC-family of oncogenes (fMYC) but also by genetic inactivation of MAX, the obligate partner of MYC. While the oncogenic properties of fMYC have been extensively studied, the tumour suppressor role of MAX and the function of fMYC in MAX-mutant cells remain unclear. Further, inactivating mutations in MGA, a gene that codes for another MAX-binding partner, have been found in lung cancer. MGA is a component of the non-canonical polycomb repressive complex 1 (ncPRC1) but its precise role in lung cancer development is unknown.

      Method

      RNA-sequencing, chromatin immunoprecipitation and proteomic analysis were performed to identify and compare the DNA binding and gene expression profiles of MYC, MGA and MAX in MAX-restituted human small cell lung cancer (SCLC)-derived cell lines.

      Result

      SCLC is a high-grade neuroendocrine type of lung cancer with recurrent inactivating mutations in MAX. Recent findings have described two major SCLC subtypes based on the high expression of either ASCL1 or NEUROD1 transcription factors. According to this, ASCL1 and NEUROD1 control the expression of different set of genes which defines the two subgroups of SCLC. Here, we found that MAX-mutant SCLC cells belong to the ASCL1-transcription factor dependent group of SCLCs. In the absence of MAX, even after ectopic overexpression of MYC, there was no recruitment of MYC to the DNA. The DNA binding profile of MAX in MAX-restituted cells remained unaltered after co-overexpression of MYC, despite opposed effects in gene expression. Moreover, restitution of MAX significantly shifted the DNA occupancy of MGA, from E2F6 consensus binding sites to MYC-consensus binding sites (E-boxes). Our observations also demonstrated that ncPRC1 complex is formed regardless of the presence or absence of MAX.

      Conclusion

      Our data supports that MYC lacks transactivation capabilities in the absence of MAX and that the tumour suppressor role of MAX relies on its capability to counteract the gene expression triggered by its partnering with fMYC. Further, we conclude that the tumor suppressor role of MGA may be related, in part, to the regulation of E2F6 promoters.

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      MA17.06 - Plakophilin 1 Enhances MYC Expression, Promoting Squamous Cell Lung Cancer (Now Available) (ID 823)

      15:45 - 17:15  |  Presenting Author(s): Pedro Pablo Medina  |  Author(s): Joel Martin-Padron, Laura Boyero, María Isabel Rodríguez, Alvaro Andrades, Inés Díaz-Cano, Paola Peinado, Carlos Baliñas, Juan Carlos Alvarez Álvarez Pérez, Isabel Fernández Coira, María Esther Fárez-Vidal

      • Abstract
      • Presentation
      • Slides

      Background

      Plakophilin 1 (PKP1) is a member of the arm-repeat (armadillo) and plakophilin gene families, being an important component of the desmosome. Although desmosomes loss-of-function has been associated with increased cell migration and pro-oncogenic activity, we have observed consistent PKP1 overexpression in patient samples of squamous cell lung cancer (SqCLC) in comparison with lung adenocarcinoma (LUAD) and non-tumoral controls from two datasets achieved by our group, and also from three additional independent datasets.

      Method

      In order to explore this paradox, we developed in vitro and in vivo PKP1 gain/loss functional models in SqCLC cell lines and also we challenged our hypothesis in some LUAD cell lines.

      Result

      Greater cell dissemination but reduced cell proliferation was observed in CRISPR-Cas9 induced, PKP1-knockout clones. Furthermore, PKP1 expression promoted cell proliferation, cell survival, and in vivo xenograft engraftment.

      Interestingly, we demonstrated through several functional experiments (chromatin immunoprecipitation, RNA immunoprecipitation, direct mutagenesis combined with luciferase assays, Western blot, qPCR... among others), and in 7 cell lines from different lung cancer subtypes (5 SqCLC and 2 LUAD cell lines), and different contexts (with and without PKP1 basal expression in order to set up gain and loss expression assays), that these pro-oncogenic activities were mediated by the functional direct relationship between PKP1 and the oncogene MYC. Specifically, PKP1 enhances MYC translation, and MYC increases PKP1 transcription, linking both proteins in a positive feedforward loop.

      Conclusion

      These observations provide a new molecular mechanism of cancer development, revealing PKP1 as a novel oncogene in SqCLC, and as an effective post-transcriptional regulator of MYC, which has been described as overexpressed in around 70% of NSCLC tumors.

      Moreover, PKP1 unveiled as a valuable diagnostic biomarker and a potential therapeutic target for SqCLC. Importantly, PKP1 inhibition may open up the possibility of indirectly targeting MYC, not only in NSCLC (where, as mentioned before, is frequently overexpressed), but also in other tumors. This is of particular interest, because MYC is an oncogene that is dysregulated in most human cancers and is acknowledged as a “most wanted” target for cancer therapy.

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      MA17.07 - Identification of AHR as a Novel Regulator of Lung Cancer Metastasis (Now Available) (ID 2331)

      15:45 - 17:15  |  Presenting Author(s): Silke Nothdurft  |  Author(s): Frank Breitenbuecher, Ross A Okimoto, Trever G Bivona, Barbara M Gruener, Michael Hoelzel, Jan Forster, Sophie Kalmbach, Alexander Schramm, Martin Schuler

      • Abstract
      • Presentation
      • Slides

      Background

      Curative treatment of early stage and locally advanced non-small cell lung cancer (NSCLC) relies on surgery and radiotherapy. Adjuvant or simultaneous platin-based chemotherapy is used for risk reduction in patients with large tumors and/or lymph node metastases. Still a large fraction of curatively treated patients dies from metastatic relapse. A better mechanistic understanding of lung cancer metastasis is expected to guide the development of novel rational interventions from prevention, early detection and treatment.

      Method

      Using a barcoded shRNA library we performed a functional in vivo screen in an orthotopic NSCLC mouse model to find target genes involved in metastatic processes. Barcoded shRNAs with significantly different representation between primary tumors and metastases were identified by next generation sequencing. Prioritized hits were functionally validated by targeted suppression in NCI-H1975 cells. Mechanistic studies were conducted in several NSCLC models in vivo and in vitro.

      Result

      We identified AHR, a ligand-activated transcription factor involved in regulation of biological responses to planar aromatic hydrocarbons, as potential modulator of lung cancer metastasis. Suppression of endogenous AHR by shRNA enhanced the migratory and invasive capacity of NSCLC cells in vitro. Importantly, NCI-H1975 with targeted suppression of AHR showed increased metastasis formation in an orthotopic model in vivo. High RNA expression of AHR correlates with lower likelihood of progression and superior overall survival in patients with stage I NSCLC. Mechanistically, AHR impacts matrix remodeling genes (MMP19, MMP24) as well as asparagine synthetase (ASNS), all of which have been implied in metastatic progression.

      Conclusion

      AHR is a novel metastasis-modulating factor in NSCLC. Its mechanism of action provides rational targets for diagnostic and therapeutic interventions.

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      MA17.08 - Discussant - MA17.05, MA17.06, MA17.07 (Now Available) (ID 3787)

      15:45 - 17:15  |  Presenting Author(s): Paul Paik

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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      MA17.09 - 5-Azacytidine Inhaled Dry Powder Formulation Profoundly Improves Pharmacokinetics and Efficacy for Lung Cancer Therapy (Now Available) (ID 172)

      15:45 - 17:15  |  Presenting Author(s): Steven Belinsky  |  Author(s): Philip J Kuehl, Carmen S Tellez, Marcie J Grimes, Michael Burke, Aaron Badenoch, Devon Dubose

      • Abstract
      • Presentation
      • Slides

      Background

      Epigenetic therapy through its ability to activate hundreds of genes silenced by promoter hypermethylation in lung cancer could produce durable and sustained tumor regression. The demethylating agent 5-azacytidine (5AZA) is unstable in aqueous solution and subject to hydrolysis and catabolism by cytidine deaminase (CDA) in liver, thereby reducing drug concentration after systemic administration prior to reaching the lung. Delivering 5AZA by inhalation could mitigate these barriers.

      Method

      A stable, respirable (3.5 µM) dry powder formulation of 5AZA was generated. Pharmacokinetic (PK) studies in rats compared systemic dosing to inhaled delivery of a dry powder or aqueous formulation of 5AZA in the presence and absence of the CDA inhibitor tetrahyroduridine (THU). An orthotopic nude rat lung cancer model compared efficacy of inhaled dry powder versus aqueous 5AZA for treatment of engrafted human adenocarcinoma (Calu6, Calu3), adenocarcinoma in situ (H358), and squamous cell (RH2) tumor lines. Three weeks following engraftment (lungs contain multiple tumors), rats were treated 4 times weekly for 4 weeks, then sacrificed to assess tumor burden and genome-wide effects on the methylome in vehicle and treated tumors using the Illumina EPIC array.

      Result

      Plasma PK showed a ~10-fold increase in area under the curve (AUC) and a 1.5 and 5-fold increase in maximum concentration (Cmax) comparing inhaled dry powder (0.6 mg/kg) to systemic (2 mg/kg, equivalent to the human injectable dose of 75 mg/m2) and inhaled aqueous (0.6 mg/kg) 5AZA that was augmented by THU. Inhaled dry powder and aqueous 5AZA PK in lung were similar and greatly exceeded systemic (30-fold Cmax; 47-fold AUC). PK in liver and brain were superior for dry powder with 7- and 26-fold increase in AUC and 7- and 3.3-fold increase in Cmax compared to systemic or aqueous dosing. The efficacy study comparing inhaled delivery of equivalent doses (0.6 mg/kg lung dose) showed dry powder was significantly better than aqueous with a 70–80% compared to 33–50% reduction in tumor burden for Calu6, Calu3, and RH2 and equally effective in largely curing H358 tumors. A significantly increased median number of genes (175–320 versus 25–270) exhibiting ≥30% demethylation of CpGs across their promoter region was seen for Calu6, Calu3, and H358 tumors exposed to dry powder versus aqueous 5AZA, with equivalent numbers of genes demethylated for RH2.

      Conclusion

      Delivery of a dry powder formulation of 5AZA via an inhaler could be used to treat local and metastatic lung cancer (Support–CA196590).

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      MA17.10 - Lactate Transporter Blockade as a Strategy to Overcome VEGF Inhibitor-Resistance in LKB1-Deficient NSCLC (Now Available) (ID 2647)

      15:45 - 17:15  |  Presenting Author(s): John Victor Heymach  |  Author(s): Irene Guijarro, Alissa Poteete, Sungnam Cho, Teng Zhou, You-Hong Fan, Emily Roarty, Monique Nilsson, Edwin Parra, Barbara Mino, Ignacio Wistuba, Jing Wang, Ferdinandos Skoulidis

      • Abstract
      • Presentation
      • Slides

      Background

      STK11/LKB1 alterations are found in 20-30% of NSCLC and used to co-occur with KRAS mutations. Because LKB1 activates AMPK, many of the best known functions of LKB1 are attributed to its ability to control metabolic alterations in cells. Our laboratory have previously reported that loss of LKB1 promotes enhanced glycolysis and elevated lactate production and more recently we demonstrated that STK11/LKB1 mutations are the strongest predictors of de novo resistance to immunotherapy in NSCLC. Prior studies have revealed an association between alterations in the LKB1/AMPK pathway and worse clinical outcomes in NSCLC and in patients treated with chemotherapy and bevacizumab. Given the roles of LKB1 in the regulation of cell metabolism and resistance to immunotherapy, it is feasible that LKB1 also impacts on the response to anti-angiogenic therapies.

      Method

      Xenograft mouse models were established by subcutaneous injection of H460 cells (LKB1-deficient) and H460 LKB1-expressing in nude mice and LKR10 (KRASG12D) LKB1 wild-type (K) or LKB1- knockout (KL) into 129Svmice. Mice were randomized to vehicle or B20-4.1.1 anti-VEGF antibody. Glycolytic activity of LKB1-intact and -deficient NSCLC cells was measured by Seahorse assay. We analyzed gene expression of SLC16A3 (MCT4) by qPCR and Western blot. Genetic disruption of MCT4 in the K and KL cell lines was done using CRISPR-Cas9 and mouse models were established by subcutaneous injection into mice.

      Result

      Mice bearing LKB1-expressing H460 xenografts treated with anti-VEGF antibody showed a significant decrease in tumor volume (p<0.05) compared with their vehicle-treated counterparts. However, mice bearing LKB1-deficient H460 xenografts showed markedly reduced efficacy of anti-VEGF therapy compared with that in LKB1-expressing xenografts. Anti-VEGF therapy significantly reduced growth of LKR10 K tumors (p<0.001) but not in LKR10 KL tumors. Microvascular density was not increased in KL tumors following anti-VEGF treatment compared to K. Human isogenic LKB1-deficient cells showed a significantly increased rate of glycolysis and lactate secretion compared with cells expressing LKB1. Human and murine LKB1-deficient cells also had increased MCT4 expression compared to K cells. Immunofluorescence and RPPA analysis of tumor samples from the K and KL mouse models showed that KL tumors upregulated MCT4 protein expression compared with K tumors (p<0.0001). The genetic disruption of MCT4 KL tumors significantly improved tumor volume reduction to anti-VEGF therapies in vivo (p<0.001).

      Conclusion

      LKB1 loss is associated with increased lactate secretion and resistance to VEGF inhibition in NSCLC. The targeting of the lactate transporter MCT4 enhance the sensitivity of LKB1-deficient NSCLC to anti-VEGF therapy.

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      MA17.11 - High Sensitivity to PD-1 Blockade Therapy After Ld1 Depletion in KRAS-Driven Lung Cancer Through CD8+/CD3+ Tumor Infiltration and PD-L1 Induction (Now Available) (ID 2562)

      15:45 - 17:15  |  Presenting Author(s): Iosune Baraibar  |  Author(s): Marta Román, Inés López-Erdozain, Ana Oliver, Anna Vilalta, Daniel Ajona, Silvestre Vicent, Carlos De Andrea, Ruben Pio, Juan José Lasarte, Alfonso Calvo, Ignacio Gil-Bazo

      • Abstract
      • Presentation
      • Slides

      Background

      PD-1/PDL-1 inhibitors are approved for non-small cell lung cancer (NSCLC). However, many patients do not benefit and therapeutic combinations are under investigation. We have previously described Id1, involved in proliferation, angiogenesis and immunosuppression, as a prognostic factor in lung adenocarcinoma (LUAD) (Ponz-Sarvise, Clin Cancer Res 2011), Id1’s role in lung cancer metastasis (Castanon, Cancer Letters 2017) and more recently shown that Id1 sustains mutant KRAS-driven progression and metastasis in NSCLC (Roman, Cancer Res 2019).

      In a previous syngeneic murine lung cancer model with depleted levels of Id1 using Id1-/- and Id1 wildtype C57BL/6 mice inoculated with Lewis Lung Carcinoma (LLC), we tested a combined therapeutic strategy targeting PD-1 and Id1, showing impaired tumor growth and increased survival (Gil-Bazo, presented at WCLC 2018).

      Here we study a combined strategy targeting PD-1 and Id1 in a KRAS-mutant murine LUAD model and the immune-related mechanisms involved.

      Method

      First, a correlation between Id1 and PD-L1 mRNA expression was studied in mutant and wild-type KRAS LUAD cohorts from The Cancer Genome Atlas data set (TCGA).

      Secondly, a syngeneic tumor model using Balb/c mice through subcutaneous injection of KRAS-mutant LUAD (Lacun3) cells and Id1-silenced Lacun3 (Id1sh) cells. In vitro, proliferation was measured in both cell lines through MTS assays. IFNg-induced PD-L1 expression in both cell lines and flow cytometry was used to evaluate its mechanistic effects on the immune response.

      After tumor cells injection, mice were treated with an anti-PD-1 (RMP-1-14) monoclonal antibody or PBS, i.p. Tumor volumes according to Id1 status in tumor cells and the treatment administered were quantified. Vectra 3.0™ multispectral microscopy was used to characterize the tumor associated immune cells in paraffin-embedded tissues from our previous syngeneic murine lung cancer model using Id1-/- and Id1 wildtype C57BL/6 mice inoculated with LLC in which the combined blockade had been reported as effective. Immune marker antibodies were used to study expression of CD3, CD4 and CD8.

      Result

      An inverse, moderate and statistically significant correlation between Id1 and PD-L1 expression in mutant and wild-type KRAS LUAD cohorts from TCGA was found in both cohorts (-0.367 and -0.351, respectively, p<0.001), indicating that Id1 depletion may lead to PD-L1 expression induction.

      In vitro assays showed that Id1 silencing reduced Lacun3 cells proliferation (p<0.001). Up-regulation of surface PD-L1 expression occurred in Id1sh cells, but not in Lacun3 cells, after receiving IFNg (p=0.0022). Mechanistically, in the syngeneic murine model, Id1 inhibition in the injected cells, combined with anti-PD-1 treatment, significantly induced a tumor growth impairment (p<0.001). An intense CD8+ and CD3+ immune cell infiltration was observed in LLC Id1-/- C57BL/6 mice treated with anti-PD1 (p<0.05 for CD3+ TILS), compared the control groups, possibly explaining the dramatic tumor growth impairment previously shown on the treated animals.

      Conclusion

      Id1 silencing may induce PD-L1 overexpression according to in silico and in vitro results. Id1 and PD-1 combined blockade in our KRAS-mutant syngeneic murine LUAD model significantly impaired tumor growth, compared to each strategy alone. A significantly increased CD3+ and CD8+ tumor infiltration and IFNg-induced PD-L1 tumor expression after the combined blockade may explain these findings.

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      MA17.12 - Discussant - MA17.09, MA17.10, MA17.11 (Now Available) (ID 3788)

      15:45 - 17:15  |  Presenting Author(s): Shantanu Banerji

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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    ES25 - Liquid Biopsy (ID 27)

    • Event: WCLC 2019
    • Type: Educational Session
    • Track: Treatment of Early Stage/Localized Disease
    • Presentations: 1
    • Now Available
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      ES25.01 - Liquid Biopsy: State of the Science (Now Available) (ID 3287)

      14:30 - 16:00  |  Presenting Author(s): Eloisa Jantus-Lewintre

      • Abstract
      • Presentation
      • Slides

      Abstract

      I. The present.

      Molecular diagnosis in cancer certainly requires the analysis of a tumor biopsy. However, in lung cancer, there is still a 20- 30% of tissue failure rates for tumor genotyping in routine pathological samples. As a consequence, liquid biopsy (LB) has emerged as a valid alternative source of information for the analysis of tumor specific alterations. LB refers to specimens obtained from body fluid such as blood, urine, saliva, cerebrospinal fluid, among others.

      In the complex matrix represented by blood, the main clinical developments have focused on the analysis of: i) circulating tumor DNA (ctDNA), which represents a small part of cell free circulating DNA released from tumor cells and, ii) circulating tumor cells (CTCs), defined as disseminated cancer cells in the bloodstream. Each of these materials offers unique opportunities to test different biomarkers and to analyze characteristics of the tumors.

      The advantages of the use of blood samples are clear: i) it is a minimally invasive way to get relevant tumor information, ii) serial samples can be obtained capturing tumor evolution in real time, iii) LB abrogates the limitations associated with tumor heterogeneity, since nucleic acids or tumor cells present in circulation recapitulate the information belonging from different tumor locations (primary tumor and metastases), iv) the development of new sensitive assays for analyses of ctDNA and CTCs allow the assessment of minimal residual disease and v) the costs of LB analysis are comparable with other molecular biology techniques already used in the clinical setting in addition to the reduced risks of complications associated with tissue biopsy. All these factors accelerated the implantation of LB in the clinical practice in oncology in several scenarios, especially in lung cancer.

      I.1.Lung Cancer. Clinical applications of liquid biopsies.

      At present, LB is no longer a promise but a reality allowing better treatment selection, real-time monitoring of lung cancer patients and early detection of acquired resistances. Figure 1 highlights the biological basis of LB as a source for biomarkers analysis and key clinical applications in lung cancer.

      •Personalized therapeutics/ Resistance detection: regarding the detection of tumor-associated genetic alterations in LB samples, there are a lot of scientific data demonstrating similar response rates to targeted therapies than the obtained in tissue biopsies. In particular, in the context of NSCLC patients with progressive or recurrent disease during treatment with TKIs, the IASLC guidelines suggest the use of LB-first algorithm to detect resistance mechanism.

      For those lung cancer patients receiving immune-based therapeutic treatments, recent data show that assessment of tumor mutational burden in plasma (bTMB) correlated with the values found in tissue and predicts efficacy of immune-checkpoint inhibitors.

      •Detection of minimal residual disease: Persistent detection of ctDNA or CTCs after local therapy or after adjuvant treatments was found associated with poor clinical outcome. In this particular clinical setting it is important to highlight that sensitivity of the methods used for ctDNA or CTCs evaluation really matters.

      •Real-time monitoring of disease: this is one of the most interesting application of LB, since tissue biopsies are intrinsically unable to capture tumor heterogeneity while ctDNA can comprehensively recapitulates clonal evolution over time, allowing to early detect and track the emergency of resistance mutations.

      II. The future.

      Current assays for LB analysis do not meet all the needs required for the fully implementation of the Precision Oncology. There is still room for improvement to reach its maximum informative potential. Hopefully, studies on exosomes, platelets, cfRNAs, metabolites, will help to have a more integrative picture of tumor status at each time it is evaluated.

      One of the clinical applications in which LB is called to play a key role is in the screening and early detection of lung cancer. In this regard, there are some interesting data coming from multiparametric (DNA and protein) plasma analysis. However, caution is required since there are still some important issues, such as clonal hematopoiesis, that need to be further considered.

      Another important challenge for LB is standardization. It is necessary to cross-validate platforms, standardize pre-analytical issues, compare sensitivity of different methodological approaches and also to work in the harmonization of bioinformatic tools for data analysis.

      It is clear that in the near future, tests based on the analysis of "liquid biopsies" will be more generalized, offering complementary information to tissue biopsies and providing valuable information to early diagnose lung cancer, to detect molecular progressions even prior to radiographic or clinical progression and as a source for real-time treatment monitoring.

      References

      Alix-Panabières C, Pantel K. Clinical Applications of Circulating Tumor Cells and Circulating Tumor DNA as Liquid Biopsy. Cancer Discov. 2016;6(5): 479-91.

      Bardelli A, Pantel K. Liquid Biopsies, What We Do Not Know (Yet). Cancer Cell. 2017; 31(2):172-179.

      Bettegowda C, Sausen M, Leary RJ, et al. Detection of circulating tumor DNA in early- and late-stage human malignancies. Sci Transl Med. 2014;6(224):224ra24

      Calabuig-Fariñas S, Jantus-Lewintre E, Herreros-Pomares A, Camps C. Circulating tumor cells versus circulating tumor DNA in lung cancer-which one will win? Transl Lung Cancer Res. 2016; 5(5):466-482

      Heitzer E, Haque IS, Roberts CE, Speicher MR. Current and future perspectives of liquid biopsies in genomics-driven oncology. Nat Rev Genet. 2019;20(2):71-88.

      Pantel K, Alix-Panabières C. Liquid biopsy: Potential and challenges. Mol Oncol. 2016; 10(3):371-3.

      Rossi G, Ignatiadis M. Promises and Pitfalls of Using Liquid Biopsy for Precision Medicine. Cancer Res. 2019;79(11):2798-2804.

      Siravegna G, Marsoni S, Siena S, Bardelli A. Integrating liquid biopsies into the management of cancer. Nat Rev Clin Oncol. 2017;14(9):531-.548

      figure 1.png

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    MA04 - Models and Biomarkers (ID 122)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Biology
    • Presentations: 2
    • Now Available
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      MA04.03 - Lung Tumorspheres Characterization Reveals Cancer Stem-Like Cells Potential Targets and Prognostic Markers in Non-Small Cell Lung Cancer (Now Available) (ID 2269)

      13:30 - 15:00  |  Author(s): Eloisa Jantus-Lewintre

      • Abstract
      • Presentation
      • Slides

      Background

      Non-small cell lung cancer (NSCLC) is the leading cause of death cancer-related worldwide due to late diagnosis and high resistance against treatments. This resistance has been associated to cancer stem-like cells (CSCs), a highly tumorigenic subpopulation for which the identification of targets and biomarkers is still under development.

      Method

      Tissue samples from 8 NSCLC patients were successfully established and cultured using a sphere-forming assay for CSCs enrichment. Adherent counterparts were used as differentiated control cells. Proliferation, chemorresistance, invasion and differentiation capacities were tested in vitro, whereas tumor initiation capacity was determined in vivo. The expression of 44 CSCs-related genes was assessed by qPCR and protein expression of the best contributors to distinguish adherent cells from tumorspheres was determined by immunoblot and immunofluorescence. The prognostic role of these genes was evaluated in a cohort of 661 resected NSCLC patients from TCGA and validated in an independent cohort of 114 resected lung adenocarcinoma patients.

      Result

      Patient-derived tumorspheres showed unlimited exponential growth, high resistance against chemotherapy, great invasion and differentiation capacities in vitro in addition to a higher tumorigenic potential than adherent cells in vivo. The expression of 17 genes was significantly overexpressed in lung tumorspheres, being NANOG, NOTCH3, CD44, CDKN1A, SNAI1, and ITGA6 the best contributors. Proteins encoded by these genes were consistently increased in tumorspheres from adenocarcinoma patients and showed differential localization and expression patterns. The expression of CDKN1A, SNAI1 and ITGA6 was associated to prognosis based on Cox regression analysis (Z-score > 1.5), so their absolute regression coefficients from a multivariate model were used to calculate a gene expression score. Kaplan-Meier survival analysis showed that patients with high score have shorter OS in the entire cohort [37.7 vs. 60.4 mo., p = 0.001] and the adenocarcinoma subcohort [36.6 vs. 53.5 mo., p = 0.003], but not in squamous cell carcinoma one. Multivariate analysis indicated that this gene expression score was an independent biomarker of prognosis for OS in both, the entire cohort [HR: 1.498; 95% CI, 1.167-1.922; p = 0.001] and the adenocarcinoma subcohort [HR: 1.869; 95% CI, 1.275-2.738; p = 0.001]. The prognostic value of this score was confirmed in an independent cohort of 114 lung adenocarcinoma patients (42.90 vs. NR mo, p = 0.020).

      Conclusion

      Proteins encoded by NANOG, NOTCH3, CD44, CDKN1A, SNAI1, and ITGA6 are potential targets against lung CSCs. Elevated gene expression levels of CDKN1A, SNAI1 and ITGA6 are associated with worse prognosis.

      Funded by CB16/12/00350 from CIBEROnc, PI12-02838, and PI15-00753 from ISCIII and Fundacion Arnal Planelles.

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      MA04.09 - Study of Exosomes in NSCLC for Biomarkers Searching (Now Available) (ID 2417)

      13:30 - 15:00  |  Author(s): Eloisa Jantus-Lewintre

      • Abstract
      • Presentation
      • Slides

      Background

      Exosomes are small membranous vesicles secreted by a most type of cells (especially in tumoral processes), around 40-130 nm of size, that carry relevant information to distant tissues and being able to modulate its physiology. Exosomes have been detected in different clinical samples and may play a key role in NSCLC, participating in several processes such as horizontal transfer of RNA from tumor to microenvironmental cells, angiogenesis, pre-metastatic niche formation, immunosuppression; and could also be key elements in stem cell differentiation (from different origins).

      The principal objective of this study was to analyze the exosomes cargo from NSCLC cell lines and primary cultures with diverse characteristics under different growth conditions: suspension cultures with cancer stem cells (CSCs) features and monolayer cultures.

      Method

      Primary cultures from resected NSCLC patients and NSCLC cell lines were successfully established. Differentiated tumor cells were cultured under adherent conditions (2D) whereas CSCs were established in suspension cultures (3D tumorspheres). Exosomes isolation was performed by ultracentrifugation. Exosomes characterization was carried out through nanovesicles tracking analysis (NTA) and electron microscopy; and the determination of surface markers through immunoblot and flow cytometry. Exosomal DNA was extracted in order to determine the mutational status of the EGFR and RAS genes by BEAMing Digital PCR (Sysmex). Transcriptomic analysis has been carried out from exosomal RNA through whole genome gene expression microarrays, (Affymetrix). The data was normalized by Robust Multi-Array Average (RMA) and analyzed using Transcriptome Analysis Console (TAC), MultiExperiment Viewer (MeV) software and Partek Genomics Suite. Statistical significance was established at (p ≤ 0.01).

      Result

      In reference to the characterization, NTA and electron microscopy showed that exosomes were obtained free of cellular debris and their size ranges from 108-125 nm, according to the size of tumor-derived microvesicles. Exosomal surface markers analyzed by immunoblot and flow cytometry were detected in samples, confirming proper isolation. Mutational analysis of EGFR and RAS genes performed on exosomal DNA shown the same pattern displayed by the origin cells. Transcriptomic analysis of the exosomal content showed that the expression of mRNAs, miRNAs and precursors were significantly different between 3D and 2D-derived exosomes. Finally, a pathway enrichment analysis was carried out to know in which biological processes (cancer-related) are involved.

      Significant differential expressions were also found between mRNAs, miRNAs and pre-miRs present in exosomes from adenocarcinoma (ADC) vs. squamous cell carcinoma (SCC). Interestingly, 7 miRNAs differentially expressed in exosomes (miR-200c; miR-29a; miR-339; miR-224; miR-31; miR-21; miR-33a) had already been identified as overexpressed in tumor tissue from NSCLC patients by our group. Moreover, miR-339 y miR-21 were related to prognosis (p < 0.05) in ADC group.

      Conclusion

      Differences in exosomal mRNA, miRNAs and pre-miRs expression have been observed between: i) lung-tumorspheres vs. more differentiated tumor cells and ii) ADC vs. SCC cultures. In addition, the same mutational pattern was detected in exosomes as compared with their parental cultures. Therefore, exosomes can be a useful source for biomarkers analysis in NSCLC.

      Supported by grant GV/2018/026, PI18/00266, & Asociación Española Contra el Cáncer (AECC Valencia).

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    P2.03 - Biology (ID 162)

    • Event: WCLC 2019
    • Type: Poster Viewing in the Exhibit Hall
    • Track: Biology
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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      P2.03-08 - Analysis of Immunosuppressive Factors Produced by CSCs Revealed Galectin-3 as Immune Modulator with Prognostic Value in NSCLC Adenocarcinoma (ID 1855)

      10:15 - 18:15  |  Author(s): Eloisa Jantus-Lewintre

      • Abstract

      Background

      The study of the tumor microenvironment is leading to a better understanding of the tumor escape from immunosurveillance and immunotherapy response. Cancer stem cells (CSCs) are targets poorly recognized by the immune surveillance system given that they favor an immunosuppressive microenvironment. The aim of this work is to study the interactions between CSCs and the immune microenvironment in NSCLC.

      Method

      Tumor cells from 8 resected NSCLC patients and 12 cell lines were cultured using a sphere forming assay for CSCs enrichment. Adherent cultures were established as differentiated controls. The gene expression of IL-4, IL-10, IL6, IL8 LGALS-3 was analyzed by RTqPCR. Gene expression results were validated at a protein level by a sensitivity bead-based multiplex immunoassay using the Millipore kit for Luminex 100/200. The prognostic value of these factors in silico was determined in a cohort of 661 patients from The Cancer Genome Atlas (TCGA) cohort. Prognostic value was assessed by Cox regression and Kaplan‐Meier curves ﴾long rank‐test﴿, considering significant when p<0.05.

      Result

      Patients’ median age was 67 years [57-74], 62% were male, and 62.5% were adenocarcinomas (ADC). Gene expression analysis revealed that lungspheres had significantly higher expression of LGALS3 compared to differentiated adherent cells. On the contrary, adherent cells had significantly higher expression of IL6. In concordance with gene expression levels, we observed significant differences in the secretion of these two soluble factors (IL-6 and Galectin-3) between adherent cells and tumorspheres. Neither expression nor secretion levels of IL-10 and IL-4 were detectable. We had not observed significant results for IL-8. Survival analysis showed that ADC patients with higher LGALS3 expression had significantly decreased overall survival (OS, 40.49 vs. 87.90 months, p= 0.005) and relapse-free survival (25.28 vs. 41.25 months, p=0.003) than the group with LGALS3 expression below the median. The multivariate analysis showed that LGALS3 expression can be established as an independent prognostic biomarker for OS [HR=1.75; 95% CI, 1.19-2.59; p=0.004] and for PFS in lung adenocarcinoma [HR=1.68; 95% CI, 1.22-2.32; p= 0.001].

      Conclusion

      Our results suggest that Galectin-3 highly secreted by lung CSCs can be involved in the modulation of the immune microenvironment. Moreover, Galectin-3 is an independent prognostic biomarker for overall survival and relapse-free survival in lung adenocarcinomas.

      Supported by grants CB16/12/00350, PI18/00266 and PI15-00753 from ISCIII and ACIF/2018/275 from GVA and FSE