Discovery of novel dual-target CDK12/PARP1 inhibitors for the treatment of triple-negative breast cancer.

Triple-negative breast cancer (TNBC) represents a highly aggressive breast cancer subtype characterized by a paucity of effective therapeutic options. Consequently, the development of targeted therapies constitutes a promising strategy for TNBC treatment. It has been demonstrated that combining CDK12 and PARP1 inhibitors can trigger synthetic lethality in TNBC cells. In the present study, employing a pharmacophore fusion strategy, we designed and synthesized a series of dual-target inhibitors against CDK12 and PARP1. Among them, compound 20b exerted potent inhibition activity against both CDK12 and PARP1 at nanomolar concentrations. It exhibited markedly superior antiproliferative effects compared with single-target inhibitors and effectively reduced pSer2-CTD (Ser2 phosphorylation) and PAR levels in TNBC cells. Furthermore, compound 20b produced robust colony formation inhibitory effects in TNBC cell lines, accompanied by cell cycle arrest and apoptosis induction. The dual-target CDK12/PARP1 inhibitor 20b developed herein represents a novel lead molecule for TNBC drug development.