Bypass signaling pathway activation mediates resistance of EML4-ALK fusion gene positive lung cancer cell line H3122 to alectinib / 中国病理生理杂志

ABSTRACT

AIM:To detect the changes of active status of bypass signaling pathways in EML4-ALK positive lung cancer cell line H3122 treated with alectinib, hepatocyte growth factor (HGF), epidermal growth factor (EGF) and transforming growth factor-α (TGF-α), and to explore the potential mechanisms.METHODS:EML4-ALK positive cell line H3122 was treated with increasing concentrations of alectinib or/and induced by HGF, EGF and TGF-α.The cell viability was measured by CCK-8 assay.The cell apoptosis was analyzed by flow cytometry.The protein levels and phosphorylation status of ALK, c-Met and EGFR, and the downstream molecules AKT, ERK, p-AKT and p-ERK were examined by Western blot.RESULTS:The viability of the H3122 cells was inhibited by alectinib in a dose-dependent manner after administrated for 72 h, and the IC50 value was 0.042 μmol/L.The concentration-growth curves of the H3122 cells shifted to the right after induced by HGF, EGF and TGF-α.After treatment with alectinib at 0.05 μmol/L for 48 h, the apoptotic rate of H3122 cells was (20.12±1.36)%, while the apoptotic rates of the cells in the groups of alectinib combined with HGF, EGF or TGF-α were (7.85±1.03)%, (5.60±0.79)% and (4.58±1.00)%, respectively.Those values were remarkably lower than those in alectinib single treatment group (P<0.05).Alectinib inhibited the protein levels of p-ALK and its downstream signaling pathway molecules, while HGF significantly up-regulated the protein levels of p-Met and its downstream p-AKT and p-ERK.Besides, EGF and TGF-α remarkablely up-regulated the protein levels of p-EGFR and its downstream p-AKT and p-ERK.Combined treatment with crizotinib and 17-DMAG successfully inhibited the viability of the H3122 cells even in the presence of the HGF and EGFR ligands, respectively.CONCLUSION:Bypass signaling pathways are activated by HGF, EGF and TGF-α in EML4-ALK positive lung cancer cell line H3122, which may be linked to alectinib resistance.