TRIM11 Promotes The Progression Of Human Prostate Cancer Through MicroRNA-5193/ERK-MEK Signal Axis

BackgroundProstate cancer(PCa)is the second cause of cancer in men and is one of the leading causes of male cancer-related deaths,especially in economically developed countries.PSA has had a key role in the early detection of prostate cancer,but the use of the PSA biomarker has some limitations in discriminating between benign prostate disease,such as prostatitis,and between benign and malignant prostate tumors,and is currently not used as a prognostic biomarker.Further studies are still needed to identify both diagnostic and prognostic biomarkers and potential molecular markers that may lead to the development of new targeted therapy for prostate cancer.Tripartite motif-containing protein 11(TRIM 11),encoded by the TRIM 11 gene,is a member of a large family of TRIM proteins.As with all the TRIM family members,TRIM 11 functions as an E3 ubiquitin ligase in humans.Members of the TRIM family have roles as regulators in diverse cell processes.Recently,TRIM11 expression was reported to be increased in high-grade gliomas and to have an oncogenic role and to be associated with the progression of glioma.However,the role of TRIM 11 in prostate cancer remains poorly understood.ObjectiveTherefore,this study aimed to investigate the regulatory effects of TRIM 11 in prostate cancer.This study may provide future prognostic,diagnostic or therapeutic biomarkers to improve the early diagnosis,treatment,and prognosis for patients with prostate cancer.Materials and MethodsTotal mRNA was extracted from 137 pairs of prostate cancer tissue and adjacent normal tissue.RT-qPCR was used to test the mRNA expression of TRIM 11 in prostate cancer tissue and adjacent normal tissue.The patients were divided into two groups according to the expression level of TRIM11.Survival analysis was performed with Kaplan-Meier test.And TRIM 11 mRNA expression levels were compared in 497 tumor tissue and 52 normal prostate tissue in GEPIA network and Oncomine database.TRIM 11 was knocked down by siRNA transfection in PC3 and DU 145 prostate cancer cell line.Cell proliferation was measured using MTT assay as previously described.Transwell assay with a 24-well transwell system was performed to determine migration and invasion.TargetScan7 software(http://www.targetscan.org/vert₇1/)was used to predict the target microRNA of TRIM11.Luciferase reporter assays were performed to explore the interaction existed among TRIM11 and miR5193.PC3 and DU 145 cells were transfected with micro-RNA mimics and TRIM11 protein level was test by western blot before and after transfection.ERK/MEK pathway protein was evaluated by western blot after siRNA TRIM11 transfection.4-week-old male BALB/c nude mice were randomly divided into three groups(n=5 per group).Then,1*107 PC3 cells were subcutaneously injected into the flank of nude mice.Tumor volumes were measured every 3 days and lasted for 21 days.The mice were sacrificed and tumor weights were analyzed.All experiments were analyzed using the GraphPad software.Results were expressed as Mean±SD.P-value was analyzed using Student's t-test and one-way ANOVA.Statistical significance was considered at P<0.05.Results1.TRIM11 mRNA expression level was significantly higher in tumor tissue than adjacent normal tissue in 137 patients(P<0.05).In GEPIA website,TRIM 11 expression level was significantly higher in 498 prostate cancer tissue than 28 normal prostate tissue.2.The mRNA expression of TRIM 11 was profiled in three stages of prostate cancer,stage T1c,stage T2,and stage T3,and patients with a more advanced stage of prostate cancer has significantly increased expression levels of TRIM11.3.Men with prostate cancer with high TRIM 11 expression levels had a significantly shorter progression-free survival(PFS)compared with those with a low level of TRIM11 expression(P=0.032).Univariate regression analysis showed that the PSA level(HR=2.111;95%CI,1.182-3.767;P=0.012),Gleason score(HR=3.562;95%CI,1.783-7.116;P=0.006),seminal vesicle invasion(HR=2.096;95%CI,1.100-3.993;P=0.025)and high(compared with low)TRIM11 expression(HR=0.593;95%CI,0.325-0.897;P=0.039)were significantly associated with poor outcome.TRIM11 over-expression was significantly correlated with an increased serum level of prostate-specific antigen(PSA),advanced tumor stage(TNM stage),and a significantly increased association with seminal vesicle invasion(SVI).4.The MTT assay showed a significant reduction in cell viability of TRIM11after TRIM 11 siRNA transfection when compared with the control group in PC3 and DU 145 cells.TRIM 11 could inhibit the migration and proliferation of DU145 and PC3 prostate cancer cell line.Overexpression of TRIM11 or control PC3 cells were injected into nude mice.The tumor volume of nude mice with overexpression of TRIM11 was larger than control at 21 days(P<0.05).At 21 days,the tumor weight of the control group was(136.6±91.3)mg.The tumor weight of overexpression of TRIM11 mice was(918.6±114.7)mg.However,the tumor weight of overexpression of TRIM11+miR5193 mimics was(447±229.9)mg,smaller than the group of overexpression of TRIM11 mice(P<0.05).5.The targeting sites on 3'-UTR of TRIM11 by miR-5193 are listed here.TRIM 11 directly interacted with miR5193.The miR-5193 mimic was successfully transfected in both PC3 and DU 145 cell lines.The endogenous protein level of TRIM 11 was measured by Western blot,which showed that the overexpression of the miR-5193 mimic significantly reduced TRIM 11 expression.6.Western blot showed that knock down of TRIM 11 was associated with down regulation of pERK1/2 and pMEK1/2.ConclusionsIn this study,in patients with prostate cancer,TRIM 11 gene was significantly upregulated in prostate cancer tissue compared with adjacent normal tissue,and increased expression levels were associated with reduced prognosis.In prostate cancer cells in vitro,TRIM 11 expression increased cell proliferation and miR5193 inhibited TRIM 11 expression.TRIM 11 promotes prostate cancer growth in vivo and was diminished by miR5193.The results of this study support that TRIM 11 was an independent prognostic biomarker in prostate cancer.miR5193 and TRIM11 axis may provide future prognostic,diagnostic or therapeutic biomarkers to improve the early diagnosis,treatment,and prognosis for patients with prostate cancer.