Abstract 5329: The role of miR-301-3P in the regulation of Rho GTPases mediated EMT signaling in castration resistant prostate cancer.

Development of cutting edge molecular techniques greatly enhanced the knowledge of the biology of the prostate cancer (CaP). These results helped us for early detection of the disease and also developing targeted therapies of CaP. It is a fact that other than Androgen Receptor (AR), there is no specific gene candidate that could be either linked for initiation, progression or treatment of CaP. Emerging evidences suggest that a small set of microRNAs (miRNA) linked to pathogenesis of CaP especially leading to castration resistant prostate cancer (CRPC). The current conventional therapies have not proven to be successful for CRPC that compelled us to identify new targets or potent small molecules to efficiently suppress the growth of advance stages of CaP. In genome wide miRNA profiling, we have found that hsa-miR-301a-3p is expressed at stage specific manner in prostate tumor as compared to controls. These results encouraged us to dissect the role of miRNA-301a in preclinical models of CaP. miR-301-3P was highly expressed (10-14 folds) in CaP cell lines (LNCaP, C4-2B, DU-145 and PC-3) when compared to normal prostate epithelial cell lines (PZHPV-7 and PrEC). Silencing specifically miR-301a-3p resulted in inhibition of proliferation, colony forming abilities, invasion, migration and cell adhesion of CaP cells. At molecular levels we found, inhibition of miR-301a-3p upregulated its direct target of tumor suppressor TXNIP/VDUP1 expression. In addition, silencing miR-301a-3p negatively activated Rho GTPases family proteins; specifically Rho1 and Rac-1 ubiquitous signaling, resulted in transcriptional down-regulation of Epithelial-Mesenchymal-Transition (EMT) markers like slug and β-catenin. Our immunofluorescence studies suggest E-cadherin is highly expressed in the membranes and at the cellular junctions when miR-301a-3p were inhibited in CRPC cells. On the contrary, over expression of miR-301-3P, increased proliferation of CaP cells and activated Rho GTPase signaling (Rho A/B/C, Rac1 and CDC42) and mesenchymal markers like slug, b-catenin resulted in invasion and migration of CaP cells. Currently, we are interrupting Rho signaling pathways, especially upstream events of RhoA effectors Rho-associated kinases (ROCK) in miR301 over expressed CaP cells and dissecting the downstream events and correlate with phenotypic changes of CaP cells. Our in vivo assays may reveal whether silencing miR-301-3p could be a potential target for the treatment of CRPC cells. Citation Format: Vittal Kurisetty, Trinath P. Das, Rama S. Reddy, Jessica Stiles, Brad Bryan, Chendil Damodaran. The role of miR-301-3P in the regulation of Rho GTPases mediated EMT signaling in castration resistant prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5329. doi:10.1158/1538-7445.AM2013-5329 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.