Abstract 1074: A novel synthetic biotinylated microRNA-1207-3p duplex targets the 3’UTR of FNDC1 and inhibits proliferation and migration of prostate cancer cells

Prostate cancer (PCa) is the second leading cause of cancer death in US men and the dysregulation of microRNAs contributes to its development. Recently we discovered that miR-1207-3p, encoded at the PVT1 gene locus on the 8q24 human chromosomal region, is significantly underexpressed in PCa cell lines and directly targets the 3’ untranslated region (UTR) of Fibronectin type III domain containing 1 (FNDC1). Moreover, using an oligonucleotide mimic and inhibitor of miR-1207-3p, we established that miR-1207-3p regulates the proliferation and migration of prostate epithelial cells. To discover the molecular targets of miR-1207-3p unbiasedly, a RNA pull-down assay needed to be performed, yet no biotinylated miR-1207-3p mimic was commercially available. Consequently, we designed and synthesized a novel synthetic biotinylated miR-1207-3p duplex, and a novel synthetic biotinylated scramble duplex (patents pending). Prior to using the novel duplexes for molecular target discovery, we compared their effects to that of the previously used commercially available miR-1207-3p mimic and scramble control on the 3’UTR of FNDC1, and PCa cell proliferation and migration. Effects were assessed using the E006AA mildly tumorigenic PCa cell line and its aggressively tumorigenic derivative, E006AA-hT. Using these two PCa cell lines transiently transfected with 3’UTR of FNDC1-containing Luc-Pair™ Duo-Luciferase expressing vector, we found that the biotinylated miR-1207-3p duplex directly targets the 3’UTR of FNDC1 in comparison to the biotinylated scramble duplex. MTT assays revealed that the biotinylated miR-1207-3p duplex significantly decreased the proliferation of both PCa cell lines in comparison to the control biotinylated scramble duplex. Interestingly, the biotinylated miR-1207-3p duplex further decreased the proliferation of the aggressively tumorigenic E006AA-hT by an extra 25%, compared to the decrease in the proliferation of the indolent E006AA, suggesting that it may have some selectivity for aggressive PCa cells. Wound healing assays revealed that the biotinylated miR-1207-3p duplex significantly inhibited migration of both PCa cell lines by about 60% in comparison to the control biotinylated scramble duplex. Notably, the mimic of miR-1207-3p had no effects on the proliferation or migration of these cell lines when compared to scramble controls. In conclusion, to our knowledge, we have designed and synthesized the first synthetic biotinylated miR-1207-3p duplex. Importantly, unlike the mimic of miR-1207-3p, this novel synthetic biotinylated miR-1207-3p duplex significantly inhibits proliferation and migration of PCa cells including those aggressively tumorigenic. Consequently, the novel synthetic biotinylated miR-1207-3p duplex is a useful new tool for miR-1207-3p molecular target discovery, and potentially as a novel therapeutic strategy in PCa. Citation Format: Dibash K. Das, J David Warren, Olorunseun O. Ogunwobi. A novel synthetic biotinylated microRNA-1207-3p duplex targets the 3’UTR of FNDC1 and inhibits proliferation and migration of prostate cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1074.