The Effects Of MiR-663 On The Progression Of Prostate Cancer Androgen-independent State

BackgroundProstate cancer (PCa) is the most common cancer in men, accounting for 25% of new cases in both the United States and Europe, where it is the second and third leading cause of male cancer deaths respectively. Clinically, prostate cancer is diagnosed as local or advanced, and treatments range from surveillance to radical local treatment or androgen-deprivation treatment (ADT). For non-surgical(advanced) androgen-dependent prostate cancer(ADPC), ADT in combination with radiation or traditional chemotherapy remains the primary treatment. Initially, >80% of such patients respond favourably to this therapy; however, most tumors relapse within 2 years often ensues independently of androgen stimulation, producing androgen-independent prostate cancer (AIPC) with increased invasion, proliferation, malignancy, at which time the disease shows poor response to any anticancer therapy and progresses to the lethal stage eventually. Thus,understanding how the prostate cancer cells survive,proliferate and invade under the low-androgen environment will shed considerable lights on possible treatment strategies for PCa.In recent years, the discovery of microRNAs has laid a new layer of complexity over the mechanisms regulating gene expression and function. microRNA are small, noncoding, single-stranded RNAs of ~22 nucleotides that negatively regulate gene expression at the posttranscriptional level, primarily through base pairing to the 3' untranslated region (UTR) of target mRNAs. Unsurprisingly, recent evidences have shown that miRNAs have diverse functions, including the regulation of cellular development, differentiation, proliferation and apoptosis. Moreover, there is evidence that PCa-related miRNAs are regulated through androgen signaling and that this regulation may contribute to the development of androgen independence. Due to the oncogenic or tumor-suppressive properties of PCa -related miRNAs, they are highly likely to be of clinical use first as biomarkers but more importantly as therapeutic targets for prostate cancer treatment ObjectiveGene screening was done through miRNA chip on the basis of AIPC and ADPC cell lines,and miRNA expression database was constructed. The regulation mechanism of miR-663 was identified through prostate cancer cell lines. Seeking the target proteins that were regulated by miR-663, and elucidating the relationship with the AIPC progression. Methods1. miRNAs screening were operated on the basis of AIPC and ADPC cell lines, and the different expression of miRNAs were confirmed through qRT-PCR.2. The functions of miR-663 were examined on the AIPC and ADPC cell lines. The synthetic miR-663 mimcs or anti-miR-663 mimcs were transfected into the cell lines to examine the effects of miR-663 on the development, proliferation and invasion.3. Indentifying accurate binding site of miR-663 target protein in the gene through bioinformatics and miRNA datebase.Verifying the relationship of the disease with the target gene by western blot and RT-PCR .Results1. qRT-PCR was performed to evaluate miR-663 expression in LNCaP, LNCaP-AI and PC3 cell lines. It was found that miR-663 expression was up-regulated in LNCaP-AI AIPC cell lines and down-regulated in LNCaP ADPC cell lines.2. Tissue Microarrays and In Situ Hybridization showed us the correlation of miR-663 expression with Gleason scores and T stage had statistical significance3. Transfection of synthetic miR-663 regulated the cellular differentiation, proliferation and invasion.4. On target gene regulantion, the miR-663 as an oncomir induced many AIPC-related gene activation.Conclusions1. In our study miR-663 promotes the growth and invasion of LNCaP and LNCaP-AI cells. Thus miR-663 plays an important role in the progression of androgen independence.2. We analyzed the level of miR-663 in the samples from ADPC and AIPC patients by In Situ Hybridization. The correlation of miR-663 expression with Gleason scores and T stage had statistical significance..3. In the present study, we choose one target mRNA KCNC4 that was correlated with the migration. As expected, the expression of KCNC4 was up-regulated in LNCaP cells transfected with miR-663.And the reason for it need to be investigated deeply4. These results suggest that miR-663would be a miRNA biomarker candidates for CaP.