Abstract 510: MicroRNA-8073 as a tumor suppressor and a potential diagnostic and therapeutic target

MicroRNAs (miRNAs) generated inside cells are also present in peripheral blood. MiR-8073 has been studied in various disease model, but its molecular function had been unknown. In this study, we demonstrated that miR-8073 regulates target genes that participate in cell survival and works as a tumor suppressor controlling only cancer cells. First, we observed that miR-8073 expression was evidently decreased in multiple types of cancer cells compared to normal cells, but was increased in cancer exosome secreted into cultured supernatant. We then transfected synthetic miR-8073 mimic into various cancer cell lines and found dramatic reduction in cell proliferation, which was not detected in normal cells. Additionally, in tumor xenograft mice model, three-time subcutaneous injections of miR-8073 mimic at 2nM suppressed 57% growth of colorectal tumor weight. Through mRNA expression analysis and in silico sequence analysis, we further identified five potential miR-8073 targets that plays critical roles in regulation of cell proliferation, cycle and apoptosis, and demonstrated that miR-8073 indeed bound with the 3'-UTR of these target mRNAs and reduced both mRNA and protein expression. These results suggest that miR-8073 is a potential tumor suppressor, possibly discarded from cancer cells for their survival out to extracellular space, and circulates in bloodstream in the form of exosome. Our findings promise miR-8073 as a novel cancer diagnostic and therapeutic target. Citation Format: Atsuko Mizoguchi, Aiko Takayama, Taiga Arai, Yuho Kida, Junpei Kawauchi, Hiroko Sudo. MicroRNA-8073 as a tumor suppressor and a potential diagnostic and therapeutic target [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 510.