Overexpression of Mdm2 induces crizotinib resistance in targeted therapy for ALK-positive NSCLC

Abstract

Objective To investigate the effect of overexpression of murine double minute 2 (Mdm2) on the sensitivity to crizotinib in the anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) cell line H3122. Methods H3122 cells with Mdm2 overexpression were established by transfection of plasmid encoding Mdm2, and the H3122 cells transfected with empty vector (EV) served as control cells. After the Mdm2 overexpression cells and control cells were treated with different concentrations of crizotinib, an ALK inhibitor, MTT assay, colony formation assay and TUNEL assay were applied to evaluate the sensitivity to crizotinib. Western blotting was used to detect the expression of ALK, its downstream proteins and biomarkers in epithelial mesenchymal transition (EMT). Results Compared with the control cells, the H3122 cells with Mdm2 overexpression were resistant to crizotinib treatment, and were tolerant to crizotinib-induced apoptosis. Biochemical analysis of signaling transduction suggested that overexpression of Mdm2 failed to restore the phosphorylation of ALK and downstream molecules. Overexpression of Mdm2 also resulted in EMT and acquisition of mesenchymal phenotype in H3122 cells. Conclusion Overexpression of Mdm2 leads to resistance to crizotinib in H3122 cells probably through the induction of EMT process.

Keywords

• alk targeted therapy
• crizotinib
• resistance
• murine double minute 2
• epithelial mesenchymal transition