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MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression by targeted repression of transcription and translation. In this study we show that miRNA-23b (miR-23b) acts as a tumor suppressor in bladder cancer. Quantitative real-time PCR analysis showed that miR-23b is significantly down-regulated in bladder cancer cell lines and tumor tissues compared to non-malignant cells and normal tissue samples. We also demonstrate that miR-23b expression has a potential to be diagnostic and prognostic biomarker in bladder cancer. High miR-23b expression is positively correlated with higher overall survival of bladder cancer patients as revealed by Kaplan-Meier analysis. ROC analysis showed that miR-23b expression can distinguish between normal and bladder cancer tissues. Further we elucidated the biological significance of miR-23b in bladder cancer. Over-expression of miR-23b in bladder cancer cells inhibited cell proliferation and impaired colony formation. Fluorescence activated cell sorting (FACS) analysis revealed that re-expression of miR-23b in bladder cancer cells induced G0/G1 cell cycle arrest and apoptosis while inhibiting cell migration and invasion. Luciferase reporter assays demonstrated that Zeb1, a crucial regulator of epithelial-to-mesenchymal transition (EMT), is a direct target of miR-23b in bladder cancer. These results show that loss of miR-23b confers a proliferative advantage and promotes bladder cancer cell migration and invasion. Furthermore, re-expression of miR-23b may be a beneficial therapeutic strategy for the treatment of human bladder cancer. [ABSTRACT FROM AUTHOR]

Genistein has been shown to inhibit cancers both in vitro and in vivo, by altering the expression of several microRNAs (miRNAs). In this study, we focused on tumor suppressor miRNAs regulated by genistein and investigated their function in prostate cancer (PCa) and target pathways. Using miRNA microarray analysis and real-time RT-PCR we observed that miR-574-3p was significantly up-regulated in PCa cells treated with genistein compared with vehicle control. The expression of miR-574-3p was significantly lower in PCa cell lines and clinical PCa tissues compared with normal prostate cells (RWPE-1) and adjacent normal tissues. Low expression level of miR-574-3p was correlated with advanced tumor stage and higher Gleason score in PCa specimens. Re-expression of miR-574-3p in PCa cells significantly inhibited cell proliferation, migration and invasion in vitro and in vivo. miR-574-3p restoration induced apoptosis through reducing Bcl-xL and activating caspase-9 and caspase-3. Using GeneCodis software analysis, several pathways affected by miR-574-3p were identified, such as ‘Pathways in cancer’, ‘Jak-STAT signaling pathway’, and ‘Wnt signaling pathway’. Luciferase reporter assays demonstrated that miR-574-3p directly binds to the 3′ UTR of several target genes (such as RAC1, EGFR and EP300) that are components of ‘Pathways in cancer’. Quantitative real-time PCR and Western analysis showed that the mRNA and protein expression levels of the three target genes in PCa cells were markedly down-regulated with miR-574-3p. Loss-of-function studies demonstrated that the three target genes significantly affect cell proliferation, migration and invasion in PCa cell lines. Our results show that genistein up-regulates tumor suppressor miR-574-3p expression targeting several cell signaling pathways. These findings enhance understanding of how genistein regulates with miRNA in PCa. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are non-protein-coding sequences that can function as oncogenes or tumor suppressor genes. This study documents the tumor suppressor role of miR-1280 in bladder cancer. Quantitative real-time PCR and in situ hybridization analyses showed that miR-1280 is significantly down-regulated in bladder cancer cell lines and tumors compared to a non-malignant cell line or normal tissue samples. To decipher the functional significance of miR-1280 in bladder cancer, we ectopically over-expressed miR-1280 in bladder cancer cell lines. Over-expression of miR-1280 had antiproliferative effects and impaired colony formation of bladder cancer cell lines. FACS (fluorescence activated cell sorting) analysis revealed that re-expression of miR-1280 in bladder cancer cells induced G2-M cell cycle arrest and apoptosis. Our results demonstrate that miR-1280 inhibited migration and invasion of bladder cancer cell lines. miR-1280 also attenuated ROCK1 and RhoC protein expression. Luciferase reporter assays demonstrated that oncogene ROCK1 is a direct target of miR-1280 in bladder cancer. This study also indicates that miR-1280 may be of diagnostic and prognostic importance in bladder cancer. For instance, ROC analysis showed that miR-1280 expression can distinguish between malignant and normal bladder cancer cases and Kaplan-Meier analysis revealed that patients with miR-1280 high expression had higher overall survival compared to those with low miR-1280 expression. In conclusion, this is the first study to document that miR-1280 functions as a tumor suppressor by targeting oncogene ROCK1 to invasion/migration and metastasis. Various compounds are currently being used as ROCK1 inhibitors; therefore restoration of tumor suppressor miR-1280 might be therapeutically useful either alone or in combination with these compounds in the treatment of bladder cancer. [ABSTRACT FROM AUTHOR]

The article discusses a research study which investigated the role of Wnt antagonist DKK1 as a tumor suppressor gene in renal cell carcinoma (RCC). The study found that the expression of DKK1 gene is genetically silenced in kidney cancer. The reexpression of DKK1 gene was found to induce apoptosis and cell cycle arrest in RCC.

This article presents a study which demonstrated that microRNA-205, small noncoding RNA that regulate the expression of human genes, induced the expression of interleukin (IL) tumor suppressor genes by targeting specific sites in their promoters. Methods used in the investigation include transfection of small RNA, quantitative real-time polymerase chain reaction, and in situ hybridization. The results revealed that microRNA-205 was silenced in prostate cancer.

The miRNAs have great potential as biomarkers and therapeutic agents owing to their ability to control multiple genes and potential to influence cellular behavior. Here, we identified that miR-23b is a methylation-silenced tumor suppressor in prostate cancer. We showed that miR-23b expression is controlled by promoter methylation and has great promise as a diagnostic and prognostic biomarker in prostate cancer. High levels of miR-23b expression are positively correlated with higher overall and recurrence-free survival in patients with prostate cancer. Furthermore, we elucidated the tumor suppressor role of miR-23b using in vitro and in vivo models. We showed that proto-oncogene Src kinase and Akt are direct targets of miR-23b. Increased expression of miR-23b inhibited proliferation, colony formation, migration/invasion, and triggered G0-G1 cell-cycle arrest and apoptosis in prostate cancer. Overexpression of miR-23b inhibited epithelial-to-mesenchymal transition (EMT) causing a decline in mesenchymal markers Vimentin and Snail and increasing the epithelial marker, E-cadherin. Depletion of Src by RNA interference conferred similar functional effects as that of miR-23b reconstitution. miR- 23b expression caused a dramatic decrease in tumor growth in nude mice and attenuated Src expression in excised tumors compared with a control miR. These findings suggest that miR-23b is a methylation-silenced tumor suppressor that may be a useful biomarker in prostate cancer. Loss of miR-23b may confer proliferative advantage and promote prostate cancer migration and invasion, and re-expression of miR-23b may contribute to the epigenetic therapy for prostate cancer. [ABSTRACT FROM AUTHOR]