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[Display omitted] • A novel scaffold and potent PARP1 PROTAC D6 was discovered by introduction of nitrogen heterocyclic linkers. • D6 exhibited remarkable selectivity of PARP1 degradation and demonstrated moderate oral absorption property. • The antitumor mechanism of D6 was elucidated by intercepting the CDC25C-CDK1 axis, thereby arresting cell cycle progression. PARP1 is a multifaceted component of DNA repair and chromatin remodeling, making it an effective therapeutic target for cancer therapy. The recently reported proteolytic targeting chimera (PROTAC) could effectively degrade PARP1 through the ubiquitin–proteasome pathway, expanding the therapeutic application of PARP1 blocking. In this study, a series of nitrogen heterocyclic PROTACs were designed and synthesized through ternary complex simulation analysis based on our previous work. Our efforts have resulted in a potent PARP1 degrader D6 (DC 50 = 25.23 nM) with high selectivity due to nitrogen heterocyclic linker generating multiple interactions with the PARP1-CRBN PPI surface, specifically. Moreover, D6 exhibited strong cytotoxicity to triple negative breast cancer cell line MDA-MB-231 (IC 50 = 1.04 µM). And the proteomic results showed that the antitumor mechanism of D6 was found that intensifies DNA damage by intercepting the CDC25C-CDK1 axis to halt cell cycle transition in triple-negative breast cancer cells. Furthermore, in vivo study, D6 showed a promising PK property with moderate oral absorption activity. And D6 could effectively inhibit tumor growth (TGI rate = 71.4 % at 40 mg/kg) without other signs of toxicity in MDA-MB-321 tumor-bearing mice. In summary, we have identified an original scaffold and potent PARP1 PROTAC that provided a novel intervention strategy for the treatment of triple-negative breast cancer. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of dihydropyridine-based PD-L1 degraders were designed and synthesized. • Summarize the SAR of dihydropyridine derivatives for the degradation of PD-L1. • Compounds maintain PD-L1 degradation after attenuating calcium channel blockade. • F4 showed best degradation activity (66.99% @20 μM) but no calcium blocking effect. • F4- induced PD-L1 degradation strengthen the T cell-mediated killing of tumor cells. Immune checkpoint blockade (ICB) by targeting programmed cell death-1/programmed cell death ligand 1 (PD-1/PD-L1) signaling pathway is a promising strategy for tumor immunotherapy. Developing small-molecules inducing PD-L1 protein degradation has been proven as an alternative and useful approach for targeting the immunotherapy pathway. Our previous study showed that Lercanidipine could down-regulate the expression of PD-L1 protein, but its calcium influx antagonistic activity hampers further development. For attenuating the unexpected calcium channel blockade effect, a series of compounds were synthesized and evaluated through structure-activity relationship (SAR) exploration. Amongst, compound F4 exhibited a loss of calcium antagonistic activity, while the PD-L1 degradation activity can still retain. Further studies indicated that F4 degraded PD-L1 dose- and time-dependently, and may function through a lysosomal-dependent manner. Furthermore, compound F4 showed a good bioavailability value of 24.9% in mice. Moreover, the F4- induced PD-L1 degradation strengthened the T cell-mediated killing of tumor cells. Our findings show the discovery of a new PD-L1 degrader, providing a potential strategy for immunotherapy. [ABSTRACT FROM AUTHOR]