Dual-targeting CD73/PD-L1 bifunctional inhibitor: a promising cancer immunotherapy strategy.

OBJECTIVES: This work aims to design and characterize a novel bifunctional small molecule that simultaneously targets PD-L1 and CD73 to enhance the therapeutic efficacy of tumor immunotherapy. METHODS: Multiple methodologies were integrated for compound screening and biological characterization, including computer-aided molecular docking, homogeneous time-resolved fluorescence (HTRF) binding assay, surface plasmon resonance (SPR), and PD-1/PD-L1 NFAT reporter cell assay. RESULTS: The lead compound CP-1 exhibited potent dual-target inhibitory activities. It blocked the PD-1/PD-L1 interaction with an IC50 of 10.27 nM and suppressed CD73 activity with an IC50 of 300.2 nM. Molecular docking simulations revealed that CP-1 stably binds to the functional domains of PD-L1 and CD73 via specific non-covalent interactions. Cellular functional assays further demonstrated that CP-1 effectively restored T cell function in the PD-1/PD-L1 reporter system, with an EC50 of 0.9 μM. CONCLUSIONS: CP-1 exhibits balanced, dual-nanomolar inhibitory activity against PD-L1 and CD73 and displays potent immunomodulatory effects at the cellular level. It serves as a promising lead candidate for developing novel bifunctional agents to advance tumor immunotherapy.