Deacetylation of miRNA-34a and miRNA-449 induces epithelial-mesenchymal transition and acquired resistance to ALK inhibitors

Treatment with ALK tyrosine kinase inhibitors often elicits profound initial antitumor responses in ALK fusion-positive patients with lung adenocarcinoma. However, patients invariably develop acquired resistance to ALK inhibitors. In this study, we aimed to identify molecular events that limit the durable response to ALK inhibition using genetic and epigenetic approaches. To identify novel mechanisms of acquired resistance to ALK inhibitors, we established in vivo and in vitro models of acquired resistance to ceritinib and crizotinib using H3122 and H2228 cells. For in vivo model, mice with established H3122-derived tumors were treated with four doses of ceritinib (50mg/kg, 75mg/kg, 87.5mg/kg, 100mg/kg) to derive ceritinib-resistant tumors. To create ceritinib-resistant lines, H3122 was cultured with increasing concentrations of ceritinib starting with the one-third maximum inhibitory concentration (IC30). Doses were increased in a stepwise manner when normal cell proliferation patterns resumed. Fresh drug was added every 72-96h. Resistant cell (H3122-LR) that grew in 1µM ceritinib were derived after approximately 6 months of culturing in the continuous presence of drug