Long non-coding RNA MIR22HG suppresses cell proliferation and promotes apoptosis in prostate cancer cells by sponging microRNA-9-3p

The present study was designed to discuss long non-coding RNA (lncRNA) MIR22HG expression in prostate cancer and to address its effect on prostate cancer cells. MIR22HG and microRNA (miR)-9-3p expressions in prostate cancer cells were examined with the use of quantitative real-time PCR (qRT-PCR). Cell counting kit (CCK)-8, colony formation, and TUNEL were conducted to determine cell viability and apoptosis. Immunofluorescence was employed for the detection of Ki67 expression, and western blotting was applied for the examination of apoptosis-related proteins. The relationship of MIR22HG and miR-9-3p was verified employing luciferase reporter assay. Indeed, low MIR22HG expression was discovered in prostate cancer cells. Subsequently, in vitro loss-of-function studies revealed that MIR22HG overexpression suppressed cell proliferation but promoted cell apoptosis, accompanied with a reduction in Ki67 and Bcl-2 expressions, as well as an elevation in Bax and cleaved caspase 3 expressions. In addition, MIR22HG was identified as a sponge of miR-9-3p and the impacts of MIR22HG overexpression on cell proliferation and apoptosis were partly hindered by miR-9-3p overexpression. In summary, MIR22HG acts as an anticancer gene in prostate cancer via inhibiting cell proliferation and promoting apoptosis by sponging miR-9-3p. This article may provide a novel insight into the treatment of prostate cancer.