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L. Mutti



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    P1.05 - Poster Session with Presenters Present (ID 457)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Early Stage NSCLC
    • Presentations: 1
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      P1.05-021 - circRNAs: Potential Novel Biomarkers for the Early Detection of Lung Cancer (ID 5020)

      L. Mutti

      • Abstract

      Background:
      Lung cancer is the leading cancer killer globally. Cancers such as colon, breast, and prostate all have relatively reliable early detection tests. In contrast, lung cancer does not. If caught early, lung cancer has a much better prognosis. Non-invasive or minimally invasive tools to improve early detection of lung cancer represents a critical unmet need. Analysis of the human transcriptome indicates that a mere 2% of the genome corresponds to protein coding transcripts, yet ~ 75% of the genome is transcribed. It is now well established that these non-coding RNAs (ncRNAs) play important regulatory functions within the cell and their expression are often altered in cancer. Circular RNAs (circRNAs) are a species of ncRNAs. They are abundant, conserved and demonstrate cell-type specific expression patterns. Moreover, they are extremely stable with half-life’s greater than 48 hours, are resistant to degradation by RNA exonucleases, and have been shown to play important roles in cancer. Taken together these suggest that circRNAs could potentially be important biomarkers in early lung cancer diagnosis.

      Methods:
      Total RNAs isolated from a panel of matched normal/tumour NSCLC adenocarcinoma (Stage IA/IB) samples (n=6) were probed for circRNAs using the Arraystar circRNA microarray. Survival was assessed on linear mRNAs with associated circRNAs using KM-Plot.

      Results:
      Interim analysis of the data has identified n=206 circRNAs with a 2-fold difference in expression between their matched normal vs. tumour counterparts. Principal Component Analysis (PCA) demonstrated a clear separation of the samples (Tumour vs. Normal). Self-Organizing Maps (SOMs) analysis generated distinctive SOMS clusters of circRNAs, while associated linear pathway enrichment for microRNA and transcriptional binding motifs identified several additional potential networks. Moreover, an analysis of linear mRNAs associated with 10 circRNAs with altered expression in adenocarcinomas found that these mRNAs were linked to overall survival, and that the majority were adenocarcinoma specific.

      Conclusion:
      Altered levels of a number of circRNAs were associated with lung adenocarcinoma. A separate cohort of squamous cell carcinomas is currently being assessed for circRNAs. At present we are validating the expression of these circRNAs in a larger cohort of specimens, and assessing whether or not these are detectable in plasma/serum from the same individuals. Overall, circRNAs may represent novel potential biomarkers for the detection of NSCLC, and may provide additional critical basic knowledge regarding the development and biology of NSCLC.

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    P3.03 - Poster Session with Presenters Present (ID 473)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Mesothelioma/Thymic Malignancies/Esophageal Cancer/Other Thoracic Malignancies
    • Presentations: 2
    • Now Available
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      P3.03-008 - Hypoxia-Induced Changes in microRNA Levels Contribute to Drug Resistance in a 3D Model of Malignant Pleural Mesothelioma (Now Available) (ID 5867)

      L. Mutti

      • Abstract
      • Slides

      Background:
      Malignant pleural mesothelioma (MPM) is an aggressive asbestos-related thoracic cancer. Chemotherapy is the most frequent treatment option but almost every patient will be confronted with recurrence of disease and drug resistance. Previous studies have used 3D spheroid cultures to investigate drug response in MPM. We showed that microRNAs are important players in MPM biology and that they contribute to the response of MPM cells to some chemotherapy drugs. In the current study we aimed to investigate the role of microRNAs in the drug resistance of a 3D spheroid model of MPM.

      Methods:
      MPM cells were grown in standard 2D culture or as 3D spheroids in low adherence round bottom multi-well plates. The structure of the spheroids was confirmed by conventional and scanning electron microscopy. MicroRNA expression was profiled using TaqMan Low Density Arrays. RT-qPCR and droplet digital PCR were used to validate candidate microRNAs. HIF1a expression was examined in MPM spheroids using immunofluorescence staining. Drug cytotoxicity was investigated in both 2D and 3D cultures using standard proliferation assays, and the effect of drugs on gene expression was analysed. MicroRNA mimics and siRNAs were used to determine the influence of microRNA and HIF1a expression on drug resistance.

      Results:
      In our adapted model of 3D cell growth, MPM cell lines formed spherical 3D structures, in contrast to the donut shapes reported with other models. MPM cells in these spheroids were more resistant to cisplatin and gemcitabine when compared to cells grown in 2D cultures. Immunofluorescence revealed a hypoxic gradient with high HIF1a expression observed in the centre of the spheroids. Spheroids also exhibited a significant up-regulation of miR-210, miR-21, miR-378a, miR-195 and miR-146b, and down-regulation of miR-320b and miR-1225b. Transfecting MPM cells in 2D culture with miR-210 or miR-21 mimics resulted in increased drug resistance, whereas HIF1a knockdown inhibited spheroid formation and decreased drug resistance. Spheroids displayed higher expression of the ABCG2 drug pump, and ABCG2 was also up-regulated in cisplatin and gemcitabine treated MPM cells.

      Conclusion:
      Our spheroid model revealed a clear impact of hypoxia on gene expression in MPM cells. Hif1a was highly expressed in the hypoxic centre of the spheroids and is an upstream regulator of the microRNAs we found to be differentially expressed. Pharmacologic and genetic modulation of microRNA and HIF1a levels altered drug resistance in MPM cells, suggesting a link between hypoxia, microRNAs and drug resistance in MPM.

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      P3.03-021 - When RON MET TAM in Mesothelioma: All Druggable for One, and One Drug for All? (ID 5025)

      L. Mutti

      • Abstract

      Background:
      Malignant pleural mesothelioma (MPM) is an aggressive inflammatory cancer associated with exposure to asbestos. Untreated, MPM has a median survival time of 6 months, and most patients die within 24 months of diagnosis. Therefore an urgent need exists to identify new therapies for treating MPM patients. The potential for therapeutically targeting receptor tyrosine kinase (RTK) signalling networks is emerging as a critical mechanism in ‘oncogene addicted’ cancer, with RTK inhibitors evolving as areas of considerable importance in cancer therapy. Furthermore, RTK hetero-dimerization has emerged as a key element in the development of resistance to cancer therapy. As such TKIs which target several RTKs may have superior efficacy compared with TKIs targeting individual RTKs. We and others have identified c-MET, RON, Axl and Tyro3 as RTKs frequently overexpressed and activated in MPM, making these attractive candidate therapeutic targets. A number of orally bioavailable small molecule inhibitors have been developed which can target these receptors. LCRF0004 specifically targets RON, whereas ASLAN002 (BMS-777607) or Merestinib (LY2801653) are orally bioavailable small molecule inhibitors which inhibit c-MET, RON, Axl and Tyro3 at nanomolar concentrations. These drugs may therefore have applicability in the treatment/management of MPM.

      Methods:
      A panel of MPM and normal pleural cell lines were screened for expression of Tyro3, c-MET, RON and Axl by RT-PCR, and subsequently examined in a cohort of patient samples comprising benign, epithelial, biphasic, and sarcomatoid histologies by qPCR. The effects of two small molecule inhibitors LCRF0004, ASLAN002 on MPM cellular health were assessed in vitro. The effects of LCRF0004 and ASLAN002 were subsequently examined in an in vivo SQ xenograft tumour model.

      Results:
      Expression of various RON isoforms, c-MET, Tyro3 and Axl were observed in all cell lines. Significantly higher expression of all genes were found in the malignant tumour material versus benign pleura and this was validated in other datasets. Both LCRF0004 and ASLAN002 demonstrated significant anti-tumour efficacy in vitro. In xenograft models ASLAN002 was far superior to LCRF0004.

      Conclusion:
      Our results suggest that a multi-TKI, targeting the RON/MET/TAM signalling pathways, may be a more effective therapeutic strategy for the treatment of MPM as opposed to targeting RON alone.

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    WS04 - Mesothelioma Workshop (Ticketed Session) (ID 416)

    • Event: WCLC 2016
    • Type: Workshop
    • Track: Mesothelioma/Thymic Malignancies/Esophageal Cancer/Other Thoracic Malignancies
    • Presentations: 1
    • Now Available
    • Moderators:
    • Coordinates: 12/04/2016, 08:00 AM - 11:00 AM, Stolz 2
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      WS04.02 - Debate – Immunotherapy Does Work in Mesothelioma (Now Available) (ID 6983)

      L. Mutti

      • Abstract
      • Presentation
      • Slides

      Abstract not provided

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