Long Non-coding RNA SNHG14 Promotes The Malignant Progression Of Prostate Cancer

BackgroundThe incidence and mortality of prostate cancer(PCa)in our country are both increasing rapidly,and its pathogenesis has not yet been fully elucidated.In recent years,many studies have confirmed that the small nucleolar RNA host gene 14(SNHG14)in the long non-coding RNA(LncRNA)family is related to the occurrence and development of a variety of cancers,however,the research on the role of SNHG14 in the pathogenesis of PCa has not been reported.ObjectiveTo clarify the expression of SNHG14 in PCa tissues and PCa cell lines,analyze the relationship between SHNG14 expression and the clinical characteristics of PCa,explore the effect of regulating the expression of SNHG14 on the biological characteristics of PCa cells,and clarify the mechanism of SNHG14 in the malignant progression of PCa.Methods1.PCa tissues and adjacent tissues of 60 patients were collected,and real-time fluorescent quantitative reverse transcription polymerase chain reaction(qRT-PCR)was used to detect the expression of SNHG14.According to the median of SNHG14 expression,the patients were divided into high expression SNHG14 group and low expression SNHG14 group,and the relationship between SNHG14 expression and the clinical characteristics and 5 years survival rate of patients with PCa was analyzed.PCa cell line(DU 145)and normal human myofibroblast stromal cell line(WPMY1)were culture respectively,and the expression of SNHG14 in the two cell lines was detected by qRT-PCR.SNHG14 small interfering RNA(si-SNHG14)and siRNA negative control(si-NC)were transfected into DU 145 cells respectively.The activity of cell proliferation of DU 145 cells was detected by CCK-8 method,the apoptosis rate of DU145 cells was detected by flow cytometry,and the invasive ability of DU 145 cells was detected by Transwell method.The protein expressions of G1/S-specific Cyclin-D1(Cyclin D1),B lymphoma-2 gene(Bcl-2),Bcl2-related X protein(Bax),activated caspase 3(Cleaved caspase 3),N-cadherin and E-cadherin were detected by Western blot.2.We searched and screened open databases to target the miRNA that binds to SNHG14,namely miR-5590-3p,then searched and screened the downstream target gene of miR-5590-3p,namely transcription factor YY1.The expression of miR-5590-3p in PCa tissues and adjacent tissues of 60 patients was detected by qRT-PCR,and the expression of YY1 was detected by Western blot,then the correlation between the two and the expression of SNHG14 was analyzed.DU 145 cells and WPMY1 cells were culture respectively,and then the expression of miR-5590-3p and YY1 in the two cell lines was detected by qRT-PCR or Western blot.si-SNHG14 and si-NC were transfected into DU145 cells respectively,and the expression of miR-5590-3p and YY1 were detected by qRT-PCR or Western blot.Wild-type(WT)and mutant(MUT)plasmids were constructed.The binding sites between miR-5590-3p and SNHG14,or between miR-5590-3p and YY1 was verified by dual luciferase reporter gene experimental analysis.The miR-5590-3p inhibitor/miR-NC was transfected alone or co-transfected with si-SNHG14 into DU 145 cells.The activity of cell proliferation of DU 145 cells was detected by CCK-8 methods,the apoptosis rate of DU 145 cells was detected by flow cytometry,and the invasive ability of DU 145 cells was detected by Transwell method.The protein expressions of YY1,Cyclin D1,Bcl-2,Bax,Cleaved caspase 3,N-cadherin and E-cadherin were detected by Western blot.Results1.The expression of SNHG14 in PCa tissue and PCa cell line DU145 was significantly higher than that in the normal control group(both P<0.001).Especially in the tissues of patients with PCa at TNM Ⅲ-Ⅳ,it is significantly higher than patients with PCa at TNM Ⅰ-Ⅱ(P<0.001).Highly expressed SNHG14 is significantly related to tumor diameter(P=0.037),lymph node metastasis(P=0.019),gleason score(P=0.004)and TNM stage(P=0.035)in patients with PCa.The 5 years survival rate of patients with high SNHG14 expression is significantly lower than that of patients with low SNHG14 expression(P=0.030).2.Compared with the cells in the si-NC and control groups,the proliferation activity and invasion ability of DU 145 cells in the si-SNHG 14 group were significantly decreased,while the apoptosis rate was significantly increased,and the protein expression of Cyclin D1,Bcl-2 and N-cadherin were significantly decreased,While the protein expressions of Bax,Cleaved caspase 3 and E-cadherin all increased significantly(all P<0.01).3.The expression of miR-5590-3p in PCa tissue and DU 145 cells was significantly lower than that in the normal control group(all P<0.001).Especially in the tissues of patients with PCa at TNM Ⅲ-Ⅳ,it is significantly lower than patients with PCa at TNM Ⅰ-Ⅱ(P<0.001),however the expression of YY1 was the opposite.In 60 cases of PCa tissues and 35 cases of TNM Ⅲ-Ⅳ PCa tissues,miR-5590-3p was negatively correlated with the expression of SNHG14(all P<0.05),while YY1 was positively correlated with the expression of SNHG14(all P<0.05).4.The expression of miR-5590-3p in DU145 cells in the si-SNHG14 group was significantly higher than that in the si-NC and control groups(both P<0.001).Compared with the miR-NC and Control groups,the proliferation activity and invasion ability of DU145 cells in the miR-5590-3p inhibitor group were significantly enhanced,while the apoptosis rate was decreased,and the protein expression of Cyclin D1,Bcl-2 and N-cadherin were all increased significantly,while the protein expression of Bax,Cleaved caspase 3 and E-cadherin all decreased significantly(all P<0.01).5.The expression of YY1 in DU145 cells in the si-SNHG14 group was significantly lower than that in the si-NC and control groups(both P<0.001).Compared with cells in the si-SNHG14 and si-SNHG14+miR-NC groups,the proliferation activity and invasion ability of the cells in the si-SNHG14+miR-5590-3p inhibitor group were significantly enhanced,while the apoptosis rate decreased,and the protein expressions of YY1,Cyclin D1,Bcl-2 and N-cadherin were significantly increased,while the protein expressions of Bax,Cleaved caspase 3 and E-cadherin were significantly decreased(all P<0.01).Compared with cells in the the si-NC group,there is no significant difference in the above detection indicators in the cells in the si-SNHG14+miR-5590-3p inhibitor group.6.Compared with the blank and the MUT groups,the relative luciferase activity of the cells in the WT-SNHG14 group and the WT-YY1 group decreased significantly(both P<0.001).Conclusions1.SNHG14 is significantly increased in PCa tissues and cells,and is related to the degree of malignancy of PCa.2.Knockdown of SNHG14 can inhibit the proliferation and invasion of PCa cells,and induce their apoptosis.3.SNHG14 can regulate the malignant process of PCa through the miR-5590-3p/YY1 axis.