Amplification of Wild-type KRAS Imparts Resistance to Crizotinib in MET Exon 14 Mutant Non-Small Cell Lung Cancer

Clin Cancer Res. 2018 Dec 1;24(23):5963-5976. doi: 10.1158/1078-0432.CCR-18-0876. Epub 2018 Aug 2.

Abstract

Purpose: MET inhibitors can be effective therapies in patients with MET exon 14 (METex14) mutant non-small cell lung cancer (NSCLC). However, long-term efficacy is limited by the development of drug resistance. In this study, we characterize acquired amplification of wild-type (WT) KRAS as a molecular mechanism behind crizotinib resistance in three cases of METex14-mutant NSCLC and propose a combination therapy to target it.

Experimental design: The patient-derived cell line and xenograft (PDX) DFCI358 were established from a crizotinib-resistant METex14-mutant patient tumor with massive focal amplification of WT KRAS. To characterize the mechanism of KRAS-mediated resistance, molecular signaling was analyzed in the parental cell line and its KRAS siRNA-transfected derivative. Sensitivity of the cell line to ligand stimulation was assessed and KRAS-dependent expression of EGFR ligands was quantified. Drug combinations were screened for efficacy in vivo and in vitro using viability and apoptotic assays.

Results: KRAS amplification is a recurrent genetic event in crizotinib-resistant METex14-mutant NSCLC. The key characteristics of this genetic signature include uncoupling MET from downstream effectors, relative insensitivity to dual MET/MEK inhibition due to compensatory induction of PI3K signaling, KRAS-induced expression of EGFR ligands and hypersensitivity to ligand-dependent and independent activation, and reliance on PI3K signaling upon MET inhibition.

Conclusions: Using patient-derived cell line and xenografts, we characterize the mechanism of crizotinib resistance mediated by KRAS amplification in METex14-mutant NSCLC and demonstrate the superior efficacy of the dual MET/PI3K inhibition as a therapeutic strategy addressing this resistance mechanism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Carcinoma, Non-Small-Cell Lung / diagnosis
  • Carcinoma, Non-Small-Cell Lung / drug therapy
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Cell Line, Tumor
  • Crizotinib / pharmacology
  • DNA Copy Number Variations
  • Disease Models, Animal
  • Drug Resistance, Neoplasm / genetics*
  • Exons*
  • Gene Amplification*
  • Gene Expression Regulation, Neoplastic
  • Humans
  • In Situ Hybridization, Fluorescence
  • Lung Neoplasms / diagnosis
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / genetics*
  • Mice
  • Models, Biological
  • Mutation*
  • Phosphatidylinositol 3-Kinases / genetics
  • Positron Emission Tomography Computed Tomography
  • Protein Kinase Inhibitors / pharmacology
  • Proto-Oncogene Proteins c-met / genetics*
  • Proto-Oncogene Proteins p21(ras) / genetics*
  • Signal Transduction / drug effects
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • KRAS protein, human
  • Protein Kinase Inhibitors
  • Crizotinib
  • Phosphatidylinositol 3-Kinases
  • MET protein, human
  • Proto-Oncogene Proteins c-met
  • Proto-Oncogene Proteins p21(ras)