Abstract:
Compounds binding to the bromodomains of bromodomain and extra-terminal (BET) family proteins, particularly BRD4, are promising anticancer agents. Nevertheless, side effects and drug resistance pose significant obstacles in BET-based therapeutics development. Using high-throughput screening of a 200,000-compound library, we identified small molecules targeting a phosphorylated intrinsically disordered region (IDR) of BRD4 that inhibit phospho-BRD4 (pBRD4)-dependent human papillomavirus (HPV) genome replication in HPV-containing keratinocytes. Proteomic profiling identified two DNA damage response factors-53BP1 and BARD1-crucial for differentiation-associated HPV genome amplification. pBRD4-mediated recruitment of 53BP1 and BARD1 to the HPV origin of replication occurs in a spatiotemporal and BRD4 long (BRD4-L) and short (BRD4-S) isoform-specific manner. This recruitment is disrupted by phospho-IDR-targeting compounds with little perturbation of the global transcriptome and BRD4 chromatin landscape. The discovery of these protein-protein interaction inhibitors (PPIi) not only demonstrates the feasibility of developing PPIi against phospho-IDRs but also uncovers antiviral agents targeting an epigenetic regulator essential for virus-host interaction and cancer development.
摘要:
与溴结构域和外末端(BET)家族蛋白的溴结构域结合的化合物,特别是BRD4,是有前途的抗癌剂。然而,副作用和耐药性在基于BET的治疗方法开发中构成重大障碍。使用高通量筛选200,000个化合物文库,我们鉴定了靶向BRD4磷酸化内在无序区域(IDR)的小分子,该区域抑制含HPV的角质形成细胞中磷酸-BRD4(pBRD4)依赖性人乳头瘤病毒(HPV)基因组复制.蛋白质组学分析鉴定了两种DNA损伤应答因子-53BP1和BARD1-对于分化相关的HPV基因组扩增至关重要。pBRD4介导的53BP1和BARD1向HPV复制起点的募集以时空和BRD4长(BRD4-L)和短(BRD4-S)同种型特异性方式发生。这种募集被磷酸-IDR靶向化合物破坏,对全球转录组和BRD4染色质景观的扰动很小。这些蛋白质-蛋白质相互作用抑制剂(PPIi)的发现不仅证明了开发针对磷酸IDR的PPIi的可行性,而且还揭示了针对病毒-宿主相互作用和癌症发展所必需的表观遗传调节因子的抗病毒剂。