miR-204 is dysregulated in metastatic prostate cancer in vitro.

During cancer progression, the genome instability incurred rearrangement could possibly turn some of the tumor suppressor micro-RNAs into pro-oncogenic ones. We aimed to investigate miR-204 in the context of prostate cancer progression using a cell line model of different levels of genome instability (LNCaP, PC3, VCaP and NCI H660), as demonstrated by the availability of ERG fusion. We studied the effect of miR-204 modulation on master transcription factors important for lineage development, cell differentiation and prostate cancer bone marrow metastasis. We followed c-MYB, ETS1 and RUNX2 transcript and protein expression and the miR-204 affected global proteome. We further investigated if these transcription factors exert an effect on miR-204 expression (qPCR, luciferase reporter assay) by silencing them using esiRNA. We found dualistic miR-204 effects, either acting as a tumor suppressor on c-MYB, or as an oncomiR on ETS1. RUNX2 and ETS1 regulation by miR-204 was ERG fusion dependent, demonstrating regulatory circuitry disruption in advanced metastatic models. miR-204 also differentially affected mRNA splicing and protein stability. miR-204 levels were found dependent on cancer hypermethylation and supported by positive feedback induced by all three transcription factors. In this regulatory circuitry among miR-204, c-MYB, RUNX2 and ETS1, the c-MYB was found to induce all three other members, but its expression was differentially affected by the methylation status in lymph node vs. bone metastasis. We demonstrate that not only tumor suppressor micro-RNA loss, but also significant genome rearrangement-driven regulatory loop perturbations play a role in the advanced cancer progression, conferring better pro-survival and metastatic potential.

Todorova K ，Metodiev MV ，Metodieva G ，Zasheva D ，Mincheff M ，Hayrabedyan S ... -  《-》

Micro-RNA-204 Participates in TMPRSS2/ERG Regulation and Androgen Receptor Reprogramming in Prostate Cancer.

Todorova K ，Metodiev MV ，Metodieva G ，Mincheff M ，Fernández N ，Hayrabedyan S ... -  《-》

Regulatory Role of mir-203 in Prostate Cancer Progression and Metastasis.

Advanced metastatic prostate cancer (PCa) is a fatal disease, with only palliative therapeutic options. Though almost 80% of cases of metastatic PCa present bone metastasis, our current understanding of the molecular mechanisms that govern this metastatic dissemination remains fragmentary. The main objective of the present study was to identify microRNA (miRNA) genes that regulate metastatic PCa. miRNA expression profiling was done in human prostate cell lines to identify dysregulated miRNA components of advanced PCa. miR-203 expression was assessed in prostate carcinoma cell lines and clinical specimens by real-time PCR and in situ hybridization. To assess the biological significance of miR-203, miR-203 was reexpressed in bone metastatic PCa cell lines followed by in vitro and in vivo functional assays. miR-203 expression is specifically attenuated in bone metastatic PCa suggesting a fundamental antimetastatic role for this miRNA. Reintroduction of miR-203 in bone metastatic PCa cell lines suppresses metastasis via inhibition of several critical steps of the metastatic cascade including epithelial-mesenchymal transition, invasion, and motility. Ectopic miR-203 significantly attenuated the development of metastasis in a bone metastatic model of PCa. Importantly, miR-203 regulates a cohort of pro-metastatic genes including ZEB2, Bmi, survivin, and bone-specific effectors including Runx2, a master regulator of bone metastasis. miR-203 is an "antimetastatic" miRNA in PCa that acts at multiple steps of the PCa metastatic cascade via repression of a cohort of prometastatic targets. miR-203 may be an attractive target for therapeutic intervention in advanced PCa.

Saini S ，Majid S ，Yamamura S ，Tabatabai L ，Suh SO ，Shahryari V ，Chen Y ，Deng G ，Tanaka Y ，Dahiya R ... -  《-》

The proto-oncogene ERG is a target of microRNA miR-145 in prostate cancer.

Prostate cancer is a leading cause of cancer mortality in men. One of the distinct characteristics of prostate cancer is over-expression of the ERG proto-oncogene. The TMPRSS2-ERG gene fusion, the most common gene fusion, is found in approximately 50% of prostate cancer cases. We show that certain microRNAs are extensively deregulated in prostate cancer cell lines and primary clinical cancer samples. MicroRNAs are capable of modulating post-transcriptional gene expression via inhibition of protein synthesis. Independent target prediction methods have indicated that the 3' untranslated region of the ERG mRNA is a potential target of miR-145. miR-145 is consistently down-regulated in prostate cancer. Here we show that the ERG 3' untranslated region is a regulative target of miR-145 in vitro. Ectopic expression of miR-145 led to a reduction in expression of the ERG protein. We analyzed 26 prostate cancer samples and corresponding normal tissue. ERG protein expression was found to be elevated in the tumor samples, together with increased expression of several ERG isoforms. We identified ERG proteins of 35 and 24 kDa, which may represent unknown ERG splice variants. Analyses of miR-145 and ERG mRNA expression revealed a general down-regulation of miR-145 irrespective of the presence or absence of translocations involving ERG. This observation indicates that down-regulation of miR-145 may contribute to the increased expression of most ERG splice variants sharing the miR-145 target sequence in their 3' untranslated region.

Hart M ，Wach S ，Nolte E ，Szczyrba J ，Menon R ，Taubert H ，Hartmann A ，Stoehr R ，Wieland W ，Grässer FA ，Wullich B ... -  《-》

MiR-129 inhibits cell proliferation and metastasis by targeting ETS1 via PI3K/AKT/mTOR pathway in prostate cancer.

New evidence suggests that microRNAs (miRNAs) play an important role in regulating the development and progression of prostate cancer. However, their specific functions and mechanisms remained to be further explored. MiR-129 has been reported in gastric cancers, colon cancer and lung cancer. In this study, we disclosed a new tumor suppresser function of miR-129 in prostate cancer. The purpose of our study is to clarify the effects of miR-129 in cellular processes correlated with cancer development and progression of prostate cancer cell by regulating ETS1. MiR-129 and ETS1 expression in prostate cancer tissues, tumor adjacent tissues and cells were tested by quantitative real-time PCR. We validated the target relationship between miR-129 and ETS1 by dual luciferase reporter gene system. MTT, colony formation, tumorigenesis assays, flow cytometry, wound healing and transwell assays were used to analyze cell viability, proliferation, migration, and invasiveness in vivo and in vitro. The level of ETS1 protein expression was detected by western blot. Here we demonstrate that miR-129 have a relatively reduced expression in prostate cancer cell lines and tissues. Morever, the miR-129 inhibits the expression of ETS1 by binding its 3'-UTR. The overexpression of miR-129 can inhibit PC-3 cell viability, proliferation, migration and invasion through targeting ETS1 by PI3K/AKT/mTOR signaling pathway. These findings suggested that miR-129 could directly suppress ETS1, which might be one of potential mechanisms in inhibiting cell processes including viability, proliferation, migration and invasiveness of prostate cancercells and it provides new clues for us to understand the carcinogenesis of prostate cancer. In addition, it may help to develop a treatment approach for ETS1-activated prostate cancer.

Xu S ，Ge J ，Zhang Z ，Zhou W ... -  《-》