To understand further the role of Met receptor overexpression in non-small-cell lung carcinoma, we forced-expressed the full-length met cDNA in the NCI-H1264 (H1264) lung carcinoma cell line with low constitutive expression of this receptor.
However, the results support a critical role of Met gene dose in NSCLC, suggesting that Met may be a specific molecular therapeutic target in selected NSCLC patients with increased Met copy number.
We analyzed MET gene copy number using FISH in two related NSCLC cell lines, one sensitive (HCC827) and one resistant (HCC827 GR6) to gefitinib therapy and in two different NSCLC patient populations: 24 never smokers or EGFR FISH-positive patients treated with gefitinib (ONCOBELL cohort) and 182 surgically resected NSCLC not exposed to anti-EGFR agents.
In small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC), and malignant pleural mesothelioma (MPM), MET is dysregulated via overexpression, constitutive activation, gene amplification, ligand-dependent activation, mutation or epigenetic mechanisms.
PXN mutations and PXN amplifications were recently identified in nonsmall-cell lung cancer (NSCLC) and amplifications were associated with MET increased copy number.
Clinicopathologic and molecular features of epidermal growth factor receptor T790M mutation and c-MET amplification in tyrosine kinase inhibitor-resistant Chinese non-small cell lung cancer.
The growing preclinical data in EGFR-mutated NSCLCs with acquired resistance to gefitinib or erlotinib has spawned the initiation or conception of clinical trials testing novel EGFR inhibitors that in vitro inhibit T790M (neratinib, XL647, BIBW 2992, and PF-00299804), MET, or IGF-1R inhibitors in combination with EGFR TKIs, and heat shock protein 90 inhibitors.
Our findings support an intimate relationship between the EGFR and MET signaling pathways in NSCLC, and they suggest that combination treatment with MET and EGFR kinase inhibitors may be beneficial in MET-amplified NSCLC by reducing selection for drug resistant clones.
Our analysis of 202 NSCLC patient specimens was consistent with these observations: levels of MET were significantly higher in NSCLC with EGFR mutations than in NSCLC with wild-type EGFR.
Most non-small cell lung cancer (NSCLC) tumors with activating mutations of the epidermal growth factor receptor (EGFR) are initially responsive to first-generation, reversible EGFR tyrosine kinase inhibitors (TKI) such as gefitinib, but they subsequently develop resistance to these drugs through either acquisition of an additional T790M mutation of EGFR or amplification of the proto-oncogene MET.
Here we report that Met protein expression and phosphorylation were associated with primary resistance to EGFR TKI therapy in NSCLC patients harboring EGFR mutations, implicating Met as a de novo mechanism of resistance.
Results from ongoing and future trials will clarify the role of MET TKIs for the treatment of NSCLC and will provide insights into the most appropriate timing for their use.
The involvement of the MET oncogene in de novo and acquired resistance of non-small cell lung cancers (NSCLCs) to tyrosine kinase inhibitors (TKIs) has previously been reported, but the precise mechanism by which MET overexpression contributes to TKI-resistant NSCLC remains unclear.
Recently, Phase I-II trial results of crizotinib, a potent dual c-MET and ALK inhibitor, demonstrated its dramatic efficacy in ALK-positive patients with advanced NSCLC.
MET tyrosine kinase inhibitor crizotinib (PF-02341066) shows differential antitumor effects in non-small cell lung cancer according to MET alterations.