The incidence and mortality statistics for oral squamous cell carcinoma (OSCC) were 10th and 12th, respectively, in human cancers diagnosed worldwide in 2008. In this study, to identify novel tumor-suppressive microRNAs (TS-miRNAs) and their direct targets in OSCC, we performed methylation-based screening for 43 miRNAs encoded by 46 miRNA genes located within 500bp downstream of 40 CpG islands and genome-wide gene expression profiling in combination with a prediction database analysis, respectively, in 18 cell lines, resulting in the identification of a novel TS-miRNA miR-596 directly targeting LGALS3BP/Mac-2 BP/90K. DNA hypermethylation of CpG island located 5’-upstream of miR-596 gene was frequently observed in OSCC cell lines (100% of 18 cell lines) and primary OSCC cases (46.2% and 76.3% of 26 Japanese and 38 Thais primary cases) in a tumor-specific manner. The ectopic transfection of double-stranded RNA (dsRNA) mimicking miR-596 or specific siRNA for LGALS3BP significantly induced growth inhibition and apoptosis in cell lines lacking miR-596 expression or overexpressing LGALS3BP, respectively, in a manner associated with a suppression of ERK1/2 phosphorylation. Moreover, we also mention the effect of dsRNA mimicking miR-596 on the growth of an OSCC cell line in vivo. Our findings define a central role for miR-596 in OSCC and suggest the potential of miR-596 as an anti-cancer agent for miRNA replacement therapy in OSCC.

Citation Format: Ken-ichi Kozaki, Hironori Endo, Tomoki Muramatsu, Mayuko Furuta, Narikazu Uzawa, Atiphan Pimkhaokham, Teruo Amagasa, Johji Inazawa. Potential of tumor-suppressive miR-596 targeting LGALS3BP as a therapeutic agent in oral 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 1846. doi:10.1158/1538-7445.AM2013-1846