FXYD6 Regulates Chemosensitivity by Mediating the Expression of Na+/K+-ATPase α1 and Affecting Cell Autophagy and Apoptosis in Colorectal Cancer

Abstract

Purpose. Chemoresistance is a challenge of improving chemotherapeutic efficacy and prolonging survival time for patients with colorectal cancer (CRC); it is the major cause of frequent recurrence, rapid metastasis, and poor prognosis for CRC patients. FXYD6 is a regulator of Na+/K+-ATPase which is depressed in chemoresistant CRC patients. However, the biological roles of FXYD6 on regulating chemoresistance in CRC are still unclear. Methods. GSE3964 and GSE69657 from GEO DataSets were used to analyze the relationship of genes and chemoresistance. The FXYD6 expression level was detected by western blotting and real-time PCR and also analyzed from TCGA DataSet. To investigate the functional role of FXYD6 and ATP-α1, FXYD6 and ATP-α1 functional cell models were constructed. Drug sensitivity and cell proliferation were performed by MTT assay. Autophagy and apoptosis were conducted by autophagy fluorescence analysis and flow cytometric analysis, respectively. Autophagy and apoptosis markers were tested by western blotting. Results. FXYD6 was downregulated in CRC resistant patients and irinotecan- (Iri-) resistant SW620 cells (SW620/Iri). FXYD6 silence inhibited cell apoptosis and enhanced prosurvival autophagy, whereas FXYD6 overexpression produced the opposite effect which alleviated the drug resistance to irinotecan and oxaliplatin of CRC cells. FXYD6 regulates chemosensitivity by mediating the expression of Na+/K+-ATPase α1 and affecting cell autophagy and apoptosis in colorectal cancer. Conclusion. FXYD6 functions as a chemosensitivity regulator which may predict the curative effect of chemotherapy in colorectal cancer.