Hypo Adenosine-To-Inosine Editing Of Microrna-455 Promotes Melanoma Metastasis

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA We have previously reported that activation of CREB in metastatic melanoma cells resulted in reduced expression of adenosine deaminase acting on RNA 1 (ADAR1), an RNA editing enzyme. We hypothesized that disruption of A-to-I editing of microRNAs alters expression of genes regulating melanoma progression. By sequencing miRs in primary vs. metastatic melanoma cells, we show that the overall microRNA editing frequencies were reduced in metastatic melanoma cells. Specifically, we found A-to-I editing in two sites of miR-455 in non-metastatic melanoma cells with accumulation of unedited miR-455 in metastatic melanoma cells. Using two animal models, we demonstrated that the unedited miR-455 promoted melanoma growth and metastasis, while the edited form suppressed these features. Unedited miR-455 promotes melanoma progression via suppression of the tumor suppressor cytoplasmic polyadenilation element binding protein (CPEB1). Thus, miR-455 A-to-I editing alters the selection of its target genes and directs its function to inhibit melanoma growth and metastasis. Taken together, our results provide a previously undescribed mechanism (microRNA editing) contributing to melanoma progression. Citation Format: Einav Shoshan, Aaron Mobley, Russell Braeuer, Takafumi Kamiya, Li Huang, Mayra Vasquez, Lee Ho Jeong, Sun Jim kim, George Calin, Anil Sood, Gal Markel, Isaiah Fidler, Menashe Bar-Eli. Hypo adenosine-to-inosine editing of microRNA-455 promotes melanoma metastasis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4969. doi:10.1158/1538-7445.AM2014-4969