Circ_0062020 Knockdown Strengthens the Radiosensitivity of Prostate Cancer Cells

BACKGROUND: Prostate cancer (PCa) is a major contributor to reduce the life quality of males. Circular RNAs were frequently reported to be associated with cancers. In the case of radiotherapy to PCa, the role of circ_0062020 was still inconclusive, which was further explored in this study. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of circ_0062020, miR-615-5p and thyroid hormone receptor interactor 13 (TRIP13) in PCa tissues and cells, as well as in normal tissues and cell. Meanwhile, the proliferation of PCa cells was evaluated by clone formation assay and cell counting kit 8 (CCK8) assay. Moreover, the metastasis of PCa cells was assessed by transwell and wound healing assays. Furthermore, the apoptosis of PCa cells was determined by flow cytometry assay. Besides, dual-luciferase reporter system was applied to verify the correlation between miR-615-5p and circ_0062020 or TRIP13, which was predicted by online tool CircRNA interactome or TargetScan. In addition, the protein expression of TRIP13 was measured by Western blot in PCa tissues and cells and normal tissues and cells. Finally, xenograft tumor assay was performed to further confirming the function of circ_0062020 in PCa in vivo. RESULTS: Circ_0062020 and TRIP13 were upregulated, while miR-615-5p was downregulated in PCa tissues and cells. Circ_0062020 knockdown or miR-615-5p overexpression inhibited the proliferation and metastasis, and promoted apoptosis, which could be reversed by miR-615-5p inhibitor or pc-TRIP13 in ionizing radiation (IR)-treated PCa cells. As expected, circ_0062020 sponged miR-615-5p to regulate TRIP13 expression in PCa cells. Circ_0062020 knockdown also suppressed PCa tumor growth in vivo. CONCLUSION: Circ_0062020 suppressed the radiosensitivity by miR-615-5p/TRIP13 axis in PCa cells, which might provide insights into the radiotherapy for PCa.