Abstract 4176: MicroRNA-193b is growth-inhibitory in Ewing sarcoma, and represses ErbB4.

Abstract

Abstract Ewing sarcoma, the second most common cancer of bone and soft tissue in adolescents and young adults, is an aggressive malignancy with poor long-term outcome. Ewing sarcoma is driven primarily by the EWS/Fli-1 fusion oncoprotein, which arises from the recurrent t(11,22) translocation. Our laboratory has been interested in identifying microRNAs (miRs) with growth-modulating properties in Ewing sarcoma, manipulation of which could potentially be used for novel therapies, as shown in preclinical studies for other cancers. We have previously shown that replacement of select miRs, normally repressed by EWS/Fli1, can inhibit the growth of Ewing sarcoma cells. To identify additional, and more potent, miRs with growth-suppressive properties in EWS, we have performed a phenotype-based, secondary miniscreen in Ewing sarcoma cell lines. This screen, using transfection of miR mimics into the EWS cell lines A673 and SK-ES-1, followed by growth assays as read-out, identified miR-193b as a strong candidate growth suppressive miR in Ewing sarcoma. Subsequent cloning and stable overexpression of endogenous miR-193b verified the growth suppressive phenotype. Examination of candidate targets further identified ErbB4 as potently repressed upon miR-193b overexpression. ErbB4 has recently been shown to play a key role in Ewing sarcoma, specifically as a driver of metastasis and as a mediator of resistance to cytotoxic chemotherapy, key biological parameters that define high-risk disease. With the need for therapy expansion in pediatric EWS, miR-193b replacement, through ErbB4 inhibition, may be a way to help control high-risk disease. Citation Format: Colin Moore, Paul Jedlicka. MicroRNA-193b is growth-inhibitory in Ewing sarcoma, and represses ErbB4. [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 4176. doi:10.1158/1538-7445.AM2013-4176