Study On Mechanism Of MiR-96 Regulating Proliferation And Invasion Of Prostate Cancer Cells

Chapter 1Comparison of Clinical and Survival Characteristics between Prostate Cancer Patients of PSA-based Screening and Clinical Diagnosis in ChinaBackground:Prostate-specific antigen(PSA)-based mass screening remains the most controversial topic in prostate cancer.PSA-based mass screening has not been widely used in China yet.The aim of our study was to evaluate the effect of the PSA-based screening in China.Methods:The cohort consisted of 1,012 prostate cancer patients.Data were retrospectively collected and clinical characteristics of the cohorts were investigated.Survival was analyzed for prostatic carcinoma of both PSA screened and clinically diagnosed patients according to clinical characteristics and the National Comprehensive Cancer Network(NCCN)risk classification.Cox Proportional Hazards Model analysis was done for risk predictor identification.Results:The median age was 71 years old.Five-year overall and prostate-cancer-specific survival in prostatic adenocarcinoma patients were 77.52%and 79.65%;10-year survivals were 62.57%and 68.60%,respectively.Survival was significantly poorer in patients with metastases and non-curative management.T staging and Gleason score by NCCN classification effectively stratified prostatic adenocarcinoma patients into different risk groups.T staging was a significant predictor of survival by COX Proportional Hazard Model.The five-year overall survivals were 87.66%,69.19%and 74.46%,respectively,and 10-year survivals were 68.50%,39.05%and 64.16%;whereas the prostate cancer-specific five-year survivals were 90.92%,69.19%and 76.31%,respectively,and 10-year survivals were 82.72%,41.74%and 65.76%,respectively in the PSA-screened,PSA-screened with later diagnosis,and clinically diagnosed groups.Conclusion:This Chinese cohort in Changchun district had a lower overall and prostate cancer survival rate than it is reported in western countries.The incidence of early-stage prostate cancer found in PSA-based mass screening was high and there were significant differences in both overall and prostate cancer-specific survival between the PSA-screened and clinically diagnosed patients.Chapter 2miR-96 promotes the growth of prostate carcinoma cells by suppressing MTSS1Background:Prostate carcinoma(PC)is one of the most common cancers for males.However,the molecular mechanisms of PC progression are still to be uncovered.MicroRNA(miRNA)has been shown to be associated with the initiation and progression of prostate cancer.Among the identified tumor-promoting miRNAs,miR-96 has been well established to contribute to PC as an oncogenic miRNA.A panel of PC patients was selected for miR-96 determination from the cohort investigated in Chapter 1.The abundance of miR-96 was indicated significantly elevated in PC samples,compared with their matched adjacent non-cancerous tissues.Also miR-96 was shown to be associated with the prognosis of PC patients.The expression of MTSS1,a putative tumor suppressor,was detected in prostate carcinoma specimen and cell lines.Hence,it is of interest to further investigate the biological role of miR-96 in PC and the possible relationship between miR-96 and MTSS1.This study is aimed to identify the new downstream target of miR-96 and the underlying mechanisms that promote the progression of PC.Methods:The expression of miR-96 and metastasis suppressor protein 1(MTSS1)in prostate cancer tissues and cell lines,as well as the expression of miR-96 in serum were detected by quantitative PCR.Also the correlation between miR-96 and MTSS1 was analyzed.The potential target of miR-96 was predicted by an online database and verified by luciferase reporter gene.The effect of miR-96 on the expression of MTS S1 and the malignant phenotype of prostate cancer including cell proliferation,migration and cloning were examined.The prostate cancer cell lines were treated with miR-96 inhibitor or overexpression to explore the underlying mechanism of miR-96 on the growth of prostate cancer.And the relationship between miR-96 and the prognosis of patients with prostate cancer were analyzed.Results:Our data reinforced the finding that the level of miR-96 was higher in PC samples and cell lines than in non-cancerous tissues and normal prostate epithelial cells.In addition,serum miR-96 abundance was also found to be elevated in PC patients.Decreasing miR-96 expression was able to suppress the proliferation,clonogenicity,and invasion of PC cells.Overexpressing miR-96 led to increased proliferation and colony formation of normal prostate epithelial cells.miR-96 level was found to be inversely associated with the abundance of MTSS1 messenger RNA(mRNA),which has been proved to be a tumor suppressor for PC.Predictive analysis indicated that there was a potential miRN A response elements(MREs)located within 3’ UTR of MTSS1 mRNA.The changes in miR-96 expression can affect the levels of MTSS1 both at mRNA and protein levels.miR-96 also suppressed the activity of luciferase reporter under the regulation of 3’ UTR of MTSS1.Further studies showed that MTSS1 restoration accounted for the effect of miR-96 reduction on PC cells.The overexpression of a recombinant MTSS1 resistant against miRNA regulation was also demonstrated to abolish the transforming effect of miR-96 on prostate epithelial cells.Conclusion:Taken together,it was found that miR-96 was shown to be associated with the prognosis of PC patients.MTSS1 is a new authentic target of miR-96 in PC.The above findings suggested that targeting miR-96 may be a promising strategy for PC treatment.