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C. Hasovits



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    MO01 - Lung Cancer Biology - Techniques and Platforms (ID 90)

    • Event: WCLC 2013
    • Type: Mini Oral Abstract Session
    • Track: Biology
    • Presentations: 1
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      MO01.08 - Identifying Strategies For The Treatment Of Acquired EGFR Tyrosine Kinase Inhibitor Resistance (ID 3187)

      10:30 - 12:00  |  Author(s): C. Hasovits

      • Abstract
      • Presentation
      • Slides

      Background
      The management of non-small cell lung cancer (NSCLC) is becoming increasingly personalised with the identification of oncogenic drivers of cancer cell growth which are able to be targeted therapeutically. The paradigm of advanced non-squamous NSCLC treatment now incorporates assessment of epidermal growth factor (EGFR) mutations and treatment with EGFR tyrosine kinase inhibitors (TKIs) in cases where sensitising mutations are found, which results in significant prolongation of progression-free survival compared to empirical chemotherapy. However, the emergence of acquired resistance to EGFR TKIs is almost universal and the two most common mechanisms of resistance include the acquisition of a second mutation in EGFR, the T790M mutation, and c-MET amplification. Approximately one-quarter of cases of resistance are yet to be defined mechanistically and furthermore, optimal subsequent treatment remains unknown. Further research is required to understand the molecular origins of the development of acquired resistance in order to develop rational treatment strategies that incorporate both targeted and cytotoxic therapies. This study is evaluating, using in vitro models, pathways involved in the development of acquired resistance to EGFR TKI and chemotherapy and evaluating critical differences according to EGFR mutation status.

      Methods
      A panel of human NSCLC cell lines with varying clinically relevant molecular characteristics is being assessed and used to develop resistance to various cytotoxic agents and EGFR TKIs, through chronic low dose exposure, as outlined in the table below:

      Cell Line Mutation Status EGFR TKI Sensitivity Resistant Cell Line Generated
      HCC827 EGFR Exon 19 deletion Sensitive Erlotinib; Cisplatin; Paclitaxel; Pemetrexed
      H1975 EGFR Exon 21 Point Mutation (L858R) and T790M mutation Resistant Cisplatin; Paclitaxel; Pemetrexed
      H1299 EGFR Wild-Type Resistant Cisplatin; Paclitaxel; Pemetrexed
      A549 EGFR Wild-Type and KRAS Mutation Resistant Cisplatin; Paclitaxel; Pemetrexed, HDAC-inhibitor
      Assessments of proliferation, cytotoxicity and key signalling pathways are being conducted to evaluate mechanisms of chemotherapeutic and targeted therapy resistance.

      Results
      Chronic low dose exposure has been successful in generating resistant cell lines to both chemotherapeutic agents and the EGFR TKI erlotinib. Cross-resistance to taxol in cisplatin-resistant cell lines has been observed, along with evidence of epithelial-to-mesenchymal transition in the development of EGFR TKI resistance. Antibody arrays of key signalling pathways are being conducted to confirm critical pathways of interest.

      Conclusion
      The panel of human NSCLC cell lines with parental lines harbouring various EGFR sensitising and resistance mutations and generated lines resistant to cytotoxic agents and EGFR TKI are a useful in vitro model to understand key pathways involved in the emergence of therapeutic resistance and to understand how both sensitising and resistant EGFR mutations influence response to cytotoxic agents. This will guide treatment strategies selected for evaluation in vivo that may influence future treatment selection for patients.

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