Abstract 512: miR-29 expression regulates B7-H3 mediated angiogenesis in medullablastoma

Abstract

Abstract B7-H3 (CD276), an immune checkpoint member of the B7/CD28 family, plays a key role in the repression of the immune response by cancer cells. B7-H3 is overexpressed exclusively on tumor and tumor-associated cells, making it an interesting therapeutic target. B7-H3 also appears to play a role outside of immune evasion, contributing to the progression of cancer via invasion, migration, and angiogenesis. Our preliminary data have confirmed the presence of B7-H3 in highly aggressive MYC+ medulloblastoma (MB) tumors. Data-mining studies revealed that B7-H3 is highly expressed across the subgroups of MB, and is correlated with MYC expression in Group 3 and 4 MBs. Recently, miR-29, a tumor-suppressor miRNA, was shown downregulating B7-H3 expression by targeting the 3' UTR of B7-H3 mRNA. Immunoblot analysis of D283 and D458 cells demonstrated reduced expression of both cellular and soluble form of B7-H3 when transfected with miR-29 plasmid. Our preliminary data have shown a novel method of targeting B7-H3 expression by miR-29 in MB cells, inhibiting the ability of MB cells to induce angiogenesis. Because both miR-29 and B7-H3 form an inversely related axis that plays a role in tumor angiogenesis, inhibition of B7-H3 by miR-29 may have potential value in developing novel antiangiogenic treatments in MB. Citation Format: Ian Purvis, Maheedhara R. Guda, Sujatha Venkataraman, Rajeev Vibhakar, Kiran K. Velpula, Swapna Asuthkar. miR-29 expression regulates B7-H3 mediated angiogenesis in medullablastoma [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 512.