lncCRLA Enhanced Chemoresistance in Lung Adenocarcinoma That Underwentepithelial-mesenchymal Transition

Abstract BackgroundEMT confers increased metastatic potential andtheresistance to chemotherapiesto cancer cells.However, the precise mechanisms of EMT-related chemotherapy resistance remain unclear.MethodsAnticancer effects were determined by MTT, soft agar, cell cycle, propidium iodide and Annexin V analysis. The effect of drugs on tumor growth was assessed using patient-derived xenograft model and nude mice model.Morphology of tumor cells were observed by phase contrast microscopy. Proteins interactions were tested by western blot and coimmunoprecipitation. Immunohistochemistry and LNA ISH were performed to determine protein and lncRNA expression. Candidate lncRNA was screened out by microarray.Resultsc-Src-mediated Caspase-8 phosphorylationessential for EMT in lung adenocarcinoma cell linespreferentially occurs in cells with themesenchymal phenotype,resultingin chemoresistance tocisplatin plus paclitaxel in patients with resectable lung adenocarcinoma and a significantly worse5-yearPFS. Cisplatin killedlung adenocarcinoma cells regardless of Caspase-8. Paclitaxel-triggered necroptosis in lung adenocarcinoma cells was dependent on the phosphorylation or deficiency ofCaspase-8, during which FADDinteracted with RIPK1 to activateRIPK1/RIPK3/MLKL signaling axis. Accompanied with c-Src-mediated Caspase-8 phosphorylation to trigger EMT, a novel lncRNA named lncCRLA was markedly upregulated andinhibited RIPK1-induced necroptosis byimpairingRIPK1-RIPK3 interaction via binding to the intermediate domain of RIPK1. Dasatinibmitigatedc-Src-mediated phosphorylationof Caspase-8-induced EMT and enhanced necroptosis in mesenchymal-like lung adenocarcinoma cells treated with paclitaxel, while c-FLIP knockdown predominantly sensitized the mesenchymal-like lung adenocarcinoma cells to paclitaxel+dasatinib.Conclusionsc-Src-Caspase-8 interaction initiatesEMT and chemoresistance viaCaspase-8 phosphorylation and lncCRLA expression, to which the dasatinib/paclitaxel liposome+siFLIPregimen was lethal.