We aimed to perform functional analysis of miR-145-5p in prostate cancer (PCa) cells and to identify targets of miR-145-5p for understanding its role in PCa pathogenesis. PC3, DU145, LNCaP PCa, and PNT1a nontumorigenic prostate cell lines were utilized for functional analysis of miR-145-5p. Its overexpression caused inhibition of proliferation through apoptosis and reduced migration in PCa cells. SOX2 expression was significantly decreased in both mRNA and protein level in miR-145-5p-overexpressed PCa cells. We proposed that miR-145-5p, being an important regulator of SOX2, carries a crucial role in PCa tumorigenesis.

Non-coding RNAs are RNA molecules that are not translated into the protein, making up the vast majority of the human genome. Long non-coding RNAs (lncRNA) are in the RNA group that has longer than 200 nucleotides, and non-protein coding transcripts. In recent years, the potential has attracted considerable attention as new important biological regulators. LncRNAs play a critical role in regulating the activity and localization of proteins, processing the production of small RNAs, and processing other RNAs. They are also involved in cell differentiation, cell cycle, proliferation, apoptosis, migration and invasion by modulation of gene expression. Abnormal expression of LncRNAs has an important role in the function of oncogenes and tumor suppressor genes. Recently, there has been an increasing number of studies on the tumorigenic effects of specific lncRNAs in the initiation and progression of cancer. In this review, general information about lncRNAs is provided, including the biological importance of lncRNAs in cancer diseases and their potential development in therapeutic applications.

Prostate cancer (PCa) is currently the most frequently diagnosed malignancy in the western countries. It is more prevalent in older men with 75% of the incident cases above 65 years old. After radical prostatectomy, approximately 30% of men develop clinical recurrence with elevated serum prostate-specific antigen levels. Therefore, it is important to unravel the molecular mechanisms underlying PCa progression to develop novel diagnostic/therapeutic approaches. In this study, it is aimed to compare the microRNA (miRNA) profile of recurrent and non-recurrent prostate tumor tissues to explore the possible involvement of miRNAs in PCa progression. Total RNA from 41 recurrent and 41 non-recurrent PCa tissue samples were used to investigate the miRNA signature in PCa specimens. First of all, 20 recurrent and 20 non-recurrent PCa samples were profiled using miRNA microarray chips. Of the differentially expressed miRNAs, miR-1, miR-133b and miR-145* were selected for further validation with qRT-PCR in a different set of 21 recurrent and 21 non-recurrent PCa samples. Data were statistically analyzed using two-sided Student's t-test, Pearson Correlation test, Receiver operating characteristic analysis. Our results demonstrated that miR-1 and mir-133b have been significantly downregulated in recurrent PCa specimens in comparison to non-recurrent PCa samples and have sufficient power to distinguish recurrent specimens from non-recurrent ones on their own. Here, we report that the relative expression of miR-1 and mir-133b have been significantly reduced in recurrent PCa specimens in comparison to non-recurrent PCa samples, which can serve as novel biomarkers for prediction of PCa progression.

Prostate cancer (PCa) is one of the leading causes of cancer deaths in men. Since there are limited treatment options available for the advanced tumors, there is an urgent need for novel diagnostic tools for PCa. Prostate secretion samples (PSS) from 23 PCa and 25 benign prostate hyperplasia (BPH) patients were obtained from Urology Department of Bagcilar Educational and Research Hospital (Istanbul). MicroRNA (miRNA) profiling of eight PSS (four from BPH, four from PCa patients) was performed using microarray. Four of significantly deregulated miRNAs were further confirmed using quantitative reverse‐transcription PCR (qRT‐PCR). Statistical analysis was performed using Student's t‐test. ROC curves were plotted with SPSS‐15.0.In this study, we aimed to identify a miRNA expression signature that could be used to distinguish PCa from BPH. MiRNA profiling of four PCa and four BPH patients with microarray revealed that miR‐361‐3p, miR‐133b and miR‐221 were significantly downregulated and miR‐203 was upregulated in PSS of PCa patients. Further qRT‐PCR analysis confirmed the altered expressions of these four miRNAs in PSS of 23 PCa and 25 BPH patients. Four miRNAs, together and individually have much power (AUC; 0.950) than PSA has (AUC; 0.463) to discriminate PCa from BPH patients.We have shown for the first time in the literature the presence of miRNAs in the PSS. We suggest PSS as a powerful non‐invasive source for evaluation of prognosis in PCa, since prostate massages can be easily applied during routine examination. Our results showed that certain differentially expressed miRNAs in PSS could be used as diagnostics markers.