PARP 抑制剂 (PARPi) 对 BRCA1 缺失肿瘤有效；然而，它们的作用仅限于具有功能性 BRCA1 的肿瘤。我们假设通过药理学降低 BRCA1 蛋白水平可以增强 PARPi 在 BRCA1 野生型肿瘤中的有效性。为了鉴定 BRCA1 下调剂，我们使用 CRISPR 介导的编辑生成了报告细胞系，并用 HiBiT 标记内源性 BRCA1 蛋白。这些报告线能够通过发光灵敏地测量 BRCA1 蛋白水平。经过验证的报告细胞用于表观遗传修饰探针的初步筛选和 6,000 多种化合物的大规模筛选。我们鉴定了 7 种可以下调 BRCA1-HiBiT 表达并与奥拉帕尼协同作用的化合物。 N-乙酰基-N-乙酰氧基氯苯磺酰胺 (NANAC)、A-443654 和 CHIR-124 三种化合物经验证可降低 BRCA1 蛋白水平并使乳腺癌细胞对奥拉帕尼的毒性作用敏感。这些结果表明 BRCA1-HiBiT 报告细胞有望开发药物以提高 PARPi 的临床效用。© 2024 作者。

PARP inhibitors (PARPi) are efficacious in BRCA1-null tumors; however, their utility is limited in tumors with functional BRCA1. We hypothesized that pharmacologically reducing BRCA1 protein levels could enhance PARPi effectiveness in BRCA1 wild-type tumors. To identify BRCA1 downregulating agents, we generated reporter cell lines using CRISPR-mediated editing to tag endogenous BRCA1 protein with HiBiT. These reporter lines enable the sensitive measurement of BRCA1 protein levels by luminescence. Validated reporter cells were used in a pilot screen of epigenetic-modifying probes and a larger screen of more than 6,000 compounds. We identified 7 compounds that could downregulate BRCA1-HiBiT expression and synergize with olaparib. Three compounds, N-acetyl-N-acetoxy chlorobenzenesulfonamide (NANAC), A-443654, and CHIR-124, were validated to reduce BRCA1 protein levels and sensitize breast cancer cells to the toxic effects of olaparib. These results suggest that BRCA1-HiBiT reporter cells hold promise in developing agents to improve the clinical utility of PARPi.© 2024 The Author(s).