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The 3rd generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs; e.g., AZD9291), which selectively and irreversibly inhibit EGFR activating and T790M mutants, represent very promising therapeutic options for patients with non-small cell lung cancer (NSCLC) that has become resistant to 1st generation EGFR-TKIs due to T790M mutation. However, eventual resistance to the 3rd generation EGFR-TKIs has already been described in the clinic, resulting in disease progression. Therefore, there is a great challenge and urgent need to understand how this resistance occurs and to develop effective strategies to delay or overcome the resistance. The current study has demonstrated that Met amplification and hyperactivation is a resistance mechanism to both 1st and 3rd generation EGFR-TKIs since both erlotinib- and AZD9291-resistant HCC827 cell lines possessed amplified Met gene and hyperactivated Met, and were cross-resistant to AZD9291 or erlotinib. Met inhibition overcame the resistance of these cell lines to AZD9291 both in vitro and in vivo, including enhancement of apoptosis or G1 cell cycle arrest. Hence, we suggest that Met inhibition is also an effective strategy to overcome resistance of certain EGFR-mutated NSCLCs with Met amplification to AZD9291, warranting the further clinical validation of our findings. [ABSTRACT FROM AUTHOR]

Human non-small cell lung cancer (NSCLC) displays activated MEK/ERK signaling due to a high frequency of K-Ras mutation and is thus a potential candidate for MEK-targeted therapy. The current study focuses on demonstrating the activity of MEK162 (binimetinib), a MEK inhibitor under clinical testing, against NSCLC and exploring possible mechanism-driven strategies to enhance its therapeutic efficacy. MEK162 inhibits the growth of human NSCLC cell lines with varied potencies through induction of G1 cell cycle arrest and apoptosis. Moreover, it induces autophagy and accordingly the combination of MEK162 with the autophagy inhibitor, chloroquine, synergistically inhibits the growth of NSCLC cells and enhances apoptosis. MEK162 activates Akt signaling while effectively inhibiting MEK/ERK signaling. Accordingly, the combination of MEK162 and BKM120 (buparlisib), a pan-PI3K inhibitor, abrogates induced Akt activation and significantly augments therapeutic efficacy against the growth of NSCLC cells both in vitro and in vivo . Hence our findings warrant further evaluation of these rational combinations in the clinic. [ABSTRACT FROM AUTHOR]