Study On The Mechanism Of Dicer And Ago2 In Progression Of Prostate Cancer

Dicer and Ago2are critical in the RNA interference pathway. Abnormal expression of Dicer and Ago2could not only block the mature of microRNAs and short interfering RNAs and inhibited their function, but also impact on the biological behavior of the cells directly. Differentiated expression of Dicer and Ago2, which could engage in carcinogenesis and progression, were demonstrated in diversity malignancies. Moreover, level of Dicer and Ago2were supposed to correlate with clinical and pathological features. Predicted by TargetScan, miR-29b-1, miR-200a, miR-370and miR-31, which differentiated expressed in prostate cancer, had a common target gene Dicer. As a critical enzyme of microRNA machinery, Dicer could be reciprocally regulated by specific miRNAs.Parti Impact of Dicer and Ago2on the biological behavior in prostate cancer cellsObjectives:To reveal the role of Dicer and Ago2in the progression of prostate cancer, altered ability of proliferation, cell cycle, apoptosis, migration and invasion were observed after knocking down Dicer and Ago2in both androgen dependent and independent cells,Methods:Dicer and Ago2were knocked-down in androgen dependent LNCaP, androgen independent PC-3and DU145prostate cancer cells. Firstly, CCK8was addressed to investigate the cell proliferation. Secondly, flow cytometry was employed to clarify the change of cell cycle and apoptosis. Thirdly, transwell chambers were adopted to identify the ability migration and invasion.Results:After knocking down Dicer and Ago2with siRNAs, proliferation was retarded dramatically in LNCaP, PC-3and DU145(P<0.05). Consequently, LNCaP was arrested in G2/M phase while PC-3and DU145were accumulated in S phase. Transfected with Dicer and Ago2shRNA, ability of migration and invasion was enhanced in PC-3-sh-Dicer, PC-3-sh-Ago2, DU145-sh-Dicer and DU145-sh-Ago cells. However, only in LNCaP-sh-Dicer, enhanced invasive capacity was observed(P <0.05). Conclusions:Dicer and Ago2could involve in the processes of cell proliferation, apoptosis, cell cycle, migration and invasion in prostate cancer. Roles of Dicer and Ago2were revealed in both androgen dependent and independent prostate cancer, providing laboratory evidence for RNA interference therapy targeting Dicer and Ago2.Part2Predictive value of Dicer and Ago2expression in metastatic prostate cancerObjectives:The purpose of current study was to assess the biological and prognostic value of Dicer and Ago2expression in metastatic prostate cancer.Methods:mRNA and protein expression level of Dicer and Ago2were evaluated in185frozen and paraffin-embedded tissues of prostate cancer using quantative PCR and immunohistochemistry, respectively.Results:Expression of Dicer and Ago2mRNA were significantly elevated compared to adjacent benign hyperplasia glands (P<0.05). While in metastatic prostate cancer, decreased Dicer and Ago2mRNA were observed (P<0.05). Analytically, level of Dicer mRNA was negatively correlated with tumor burden of the patient (R=-0.230, P=0.026). Ago2mRNA was also negatively correlated with volume of the lesions (R=-0.178, P=0.019), so did the main Gleason score (R=-0.239, P=0.002). In metastatic prostate cancer, Dicer and Ago2protein expression level were lower in the tissue with Gleason score5relative to that with Gleason score4(P<0.05). Ago2protein expression were less in the tissue of Gleason score5compared to that of Gleason score4and3in localized prostate cancer.Conclusions:Expression of Dicer and Ago2decreased in metastatic prostate cancer and in the tumor tissues of higher Gleason score. Dicer and Ago2might be the predictive biomarker for metastasis and in tumor risk stratification.Part? Expression of microRNAs targeted Dicer in prostate cancer tissuesObjectives:Predicted by TargetScan, miR-29b-l, miR-200a, miR-370and miR-31, which differentiated expressed in prostate cancer, had a common target gene Dicer. Previous studies had already demonstrated that Dicer involved in the prostate carcinogenesis, engaging the process of cell proliferation, apoptosis and migration. As a critical enzyme of microRNA machinery, Dicer could be reciprocal regulated by specific miRNAs. Here we explore the relationship of miR-29b-1、miR-200a、 miR-370、miR-31with dicer, and evaluate the prognostic value for clinical pathological features.Methods:Quantative PCR was used to detect microRNAs and U6expression in frozen prostate cancer tissues and adjacent benign prostate hyperplasia glands. Relationship were analyzed between microRNAs and clinical features.Results:Dicer mRNA level demonstrated negative correlation with miR-200a (R=-0.419, P=0.015) and miR-31(R=-0.273, P=0.008). Compared with adjacent benign glands, expression of miR-200a and miR-31were lower in prostate cancer tissues (P<0.05). Furthermore, in metastatic prostate cancer, level of miR-200a, miR-370and miR-31was dramatically higher than that in localized prostate cancer. In addition, elevated level of miR-200a and miR-31were supposed to be relevant with castration resistant prostate cancer.Conclusions:Dicer could be a potential target of miR-200a and miR-31. Diversely expressed miR-200a and miR-31might involve in carcinogenesis, migration and the behavior of castration resistant prostate cancer, taking the possibility of being biomarkers for monitoring the progression of prostate cancer.