BRD1-mediated Acetylation Promotes Integrin αV Gene Expression via Interaction with Sulfatide

Abstract: Integrin αV (ITGAV) gene expression is often dysregulated in cancers especially in hepatocellular carcinoma (HCC); however, the mechanism of regulation is poorly understood. Here, it is demonstrated that sulfatide activated integrin αV gene transcription, through histone H3K9/14 acetylation at the promoter, and high integrin αV expression are closely associated with poor prognosis. To elucidate the mechanism of regulation of acetylation, sulfatide-bound proteins were screened by mass spectrometry (MS), and BRD1 (bromodomain containing protein 1) was identified as an interacting protein that also co-localized with sulfatide in HCC cells. BRD1 was also formed a complex with Sp1, which was recruited to the integrin αV gene promoter. Sulfatide was also found to induce BRD1, MOZ (monocytic leukemia zinc finger) and HBO1 (histone acetyltransferase binding to ORC1) acetyltransferase multi-protein complex recruitment to the integrin αV promoter, which is responsible for histone H3K9/14 acetylation. Finally, knockdown of BRD1 limited sulfatide-induced H3K9/14 acetylation and occupancy of MOZ or HBO1 on integrin αV gene promoter. Implications: This study demonstrates that sulfatide interaction with BRD1 mediates acetylation and is important for regulation of integrin αV gene expression.