LncRNA UNC5B-AS1 promotes malignant progression of prostate cancer by competitive binding to caspase-9.

OBJECTIVE: Accumulating evidence determined that lncRNA plays important roles in the development and occurrence of cancers. Prostate cancer is the second most common type of cancer and one of the top five cancers for the cause of male death in the world. Therefore, this study was to explore the regulatory mechanism of lncRNA in chemoresistance of PC. MATERIALS AND METHODS: qRT-PCR was used to detect the mRNA expression of FEZF1AS1, miR-25- 3p and ITGB8. Western blot was applied to measure the protein expression of ITGB8 E- cadherin, N-cadherin, Vimentin, LC3I, LC3II, ATG5 and Beclin-1. In addition, CCK-8 assay was used to assess cell proliferation of transfected cells. Luciferase reporter assay and RIP assay were used to determine the relationship among FEZF1-AS1, miR-25-3p and ITGB8. RESULTS: In this study, the expression of FEZF1-AS1 and ITGB8 was upregulated, whereas the expression of miR-25-3p was downregulated in PC tumor tissues and PC/PTX cells. Luciferase reporter assay and RIP assay determined that miR-25-3p was a target of FEZF1-AS1 and ITGB8 was a target mRNA of miR-25-3p. Interestingly, knockdown of FEZF1-AS1 could inhibit cell viability and EMT and promoted cell autophagy in PC/PTX cells, but inhibition of miR25-3p or promotion of ITGB8 could reverse the effects of si-FEZF1-AS1 on PC/PTX cells. CONCLUSIONS: In this study, we found that lncRNA FEZF1-AS1 promoted chemoresistance, autophagy and epithelial-mesenchymal transition (EMT) through regulation of miR-25- 3p/ ITGB8 axis in PC, providing a new regulatory mechanism of PC and a novel therapeutic target.