The Function And Molecular Mechanism Of Long Non-coding RNA MIR22HG In Prostate Cancer

Objective:To screen out abnormal long non-coding RNAs in prostate caner.To explore the effect of MIR22 HG on proliferation,migration,apoptosis and EMT of prostate cancer cells.To preliminarily investigate the molecular mechanism of MIR22 HG in regulating prostate cancer progression.To provide new targets for the diagnosis and treatment of prostate cancer.Methods:1.Lnc RNAs microarray was used to detect the differentially expressed lnc RNAs in prostate cancer and matched adjacent tissues.TCGA corhort and GSE6919 corhort were analysed to verify MIR22 HG expression obtained from microarray results.The expression level of MIR22 HG in 18 pairs of prostate cancer tissues and matched adjacent tissues were detected by q RT-PCR.2.q RT-PCR was used to detect the expression level of MIR22 HG in four prostate cancer cell lines(PC3 、 DU145 、 LNCa P and 22RV1)and non-cancerous human prostate cell line(RWPE-1).MIR22HG-si RNA or overexpressing plasmid of MIR22 HG was transfected into prostate cancer cell,and the knockdown or overexpressed efficiency was evaluated by q RT-PCR.After downor up-regultion of MIR22 HG in prostate cancer cells,CCK8 assay was used to detect cell proliferation,transwell was used to detect cell migration,flow cytometry was applied to detect cell apoptosis,western bloting was used to detect the EMT-related protein expression.Xenograft tumor erpriments were conducted to verify the effect of MIR22 HG overexpressing or silencing on subcutaneous tumorgenesis.3.Bioinformatics analysis was performed to predict the candidate miRNAs sponged by MIR22 HG.After down-or up-regultion of MIR22 HG in prostate cancer cells,q RT-PCR was used to examine the expression level of targeted miRNAs.Luciferase reporter assay was provided to verify the binding of miR-4428 to MIR22HG-3’UTR.The expression level of miR-4428 in 18 pairs of prostate cancer tissues and matched adjacent tissues were detected by q RT-PCR.The relationship between MIR22 HG and miR-4428 was screened by Pearson correlation analysis.In gain-of-function and loss-of-function studies,the role of miR-4428 in prostate cancer cells was further evaluated by CCK8,transwell,flow cytometry and western bloting.A series of rescue experiments was studied to verify that MIR22 HG inhibit the progrsession of prostate cancer via miR-4428.Results:1.Microarray analysis showed that the expression of MIR22 HG in prostate cancer tissues was significantly lower than that in adjacent tissues.The expression of MIR22 HG in prostate cancer tissues was significantly downregulated by TCGA and GEO database.q RT-PCR results further validated that MIR22 HG expression level was lower in 18 prostate cancer tissues than in adjacent non-cancerous tissues.2.QRT-PCR showed that the expression of MIR22 HG in normal prostate epithelial cells was significantly higher than that in prostate cancer cell lines.Overexpression of MIR22 HG can inhibit the proliferation,migration,and induce apoptosis,and block the EMT process of prostate carcinoma cells.While MIR22 HG knockdown gives the opposite result.In addition,tumor xenograft assay showed that MIR22 HG overexpressed can reduce the growth of prostate cancer,meanwhile,MIR22 HG downregulated can promote the growth of prostate cancer.Both in vivo and in vitro experiments illustrated that MIR22 HG plays a certain protective role in the occurrence and development of prostate cancer.3.Mi R-4428 is highly expressed in prostate cancer cells and prostate cancer tissues,and miR-4428 expression level is negatively correlated with MIR22 HG.Double luciferase experiment showed that MIR22 HG and miR-4428 bind to each other.Overexpression of MIR22 HG can promote the proliferation,migration,and inhibit apoptosis,and activate the EMT process of prostate carcinoma cells.While miR-4428 knockdown gives the opposite result.Cell functional recovery assay showed that miR-4428 could weaken the regulation of MIR22 HG on prostate cancer.Conclusion:MIR22HG is lowly expressed in prostate cancer cell lines and prostate cancer tissues,it exerts the ability to inhibit the proliferation,migration,and promote apoptosis,and inhibit the EMT process of prostate carcinoma cells.MIR22 HG functioned as a ce RNA to downregulate miR-4428 expression,thereby regulating the proliferation,migration,apoptosis and EMT process in prostate cancer cell.