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J. Alban
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P1.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 233)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P1.04-001 - MET/RON Inhibition in KRAS Mutated Non Small Cell Lung Cancer (ID 2174)
09:30 - 09:30 | Author(s): J. Alban
- Abstract
Background:
Molecular genetics have allowed us to categorize non-small cell lung cancer (NSCLC) based on their genetic profile. KRAS mutations occur in 25-30% of NSCLCs. KRAS regulates cellular function in response to growth factors and their receptors. When mutated, KRAS is constitutively active and is responsible for driving tumor oncogenesis. Direct inhibition of KRAS has not been a successful clinical strategy. The strategy of synthetic lethality (targeting a non-lethal defect in cancer cells combined with a second defect, that together make the cancer cell more susceptible to treatment) has gained traction in recent years. Several synthetic lethal targets have been identified with KRAS. We have previously shown that MET plays an important role in the oncogenic addiction observed in KRAS mutated NSCLC and contributes to both tumor growth and metastasis. However, the development of resistance in MET targeting due to upregulation of RON, a related receptor tyrosine kinase, is also evident. Our hypothesis is that dual targeting of MET and RON may be synthetic lethal to KRAS mutated NSCLC and studies to investigate this as a potential therapeutic strategy are warranted.
Methods:
MET- and RON-specific siRNAs (small molecule inhibitors), crizotinib, and the ligand for MET (hepatocyte growth factor), were used in in vitro assays. Immunoblotting, cell viability, and cell migration assays were carried out in a panel of KRAS mutated as well as KRAS wild type NSCLC cells. In addition, human bronchial epithelial cells (HBECs) that were rendered tumorigenic with sequential mutations in CDk4, hTERT, p53, and KRAS genes were also used.
Results:
Our analysis of a panel of NSCLC cells showed that most KRAS mutant cell lines express both MET and RON, and stimulation with HGF activated KRAS effector pathways such as MAPK, AKT and S6RP. When we silenced MET expression with siRNA, it led to upregulation of RON, indicating the interaction between MET and RON. Cell viability assays using crizotinib showed that KRAS mutant cell lines (A549 and H460) are three-fold more sensitive than KRAS wild type cells (H1975 and H1437), and cells with MET amplification (H1993) showed the highest response. Preliminary data with the KRAS-transformed HBECs also showed that they are more sensitive to crizotinib inhibition than the non-transformed control HBECs. Wound healing assays with these same cells showed a similar trend in MET specific inhibition of cell migration in KRAS-mutated cells compared to wild type cells.
Conclusion:
These data highlight the potential therapeutic benefit of targeting MET and RON simultaneously in a subpopulation of KRAS mutated NSCLC patients who may have MET overexpression or amplification. Based on KRAS oncogenic addiction to MET, we propose that NSCLC cells that are MET amplified and KRAS mutated are potentially synthetic lethal and will benefit from dual MET/RON treatment
