Inhibition of tumor immune escape by blocking PD-1/PD-L1 engagement with dual-targeting molecularly imprinted polymer layer

Abstract

Blocking the binding of PD-1/PD-L1 has become an effective strategy in inhibition of tumor immune escape. At present, it mainly depends on the employment of macromolecular antibodies, which target PD-1/PD-L1 protein through binding one of PD-1 or PD-L1 domains. In this study, we present a different strategy, an aptamer modified molecularly imprinted polymer layer (APD–PD-L1–MIPL), to break PD-1/PD-L1 binding for the inhibition of tumor immune escape. The APD–PD-L1–MIPL is prepared by a MIP layer on the surface of CaCO3 nanospheres using the peptide segment of the PD-L1 protein as a template. The subsequent removal of CaCO3 nanospheres core formats the MIP layer, to ensure high specifically matching capacity and short equilibrium time. A PD-L1 antagonistic DNA aptamer, is modified into the MIP layer to enhance recognition capacity, resulting in dual-targeting functionality. The APD–PD-L1–MIPL is able to bind PD-L1 and allow suppressing the engagement of PD-L1 with PD-1, inducing to block of the downstream signaling pathways and, therefore, restore T cell function and inhibition of cancer growth. The APD–PD-L1–MIPL can quantitatively detect the bound proteins and the LOD of APD–PD-L1–MIPL is 0.003 mg mL−1. This strategy enables provide a new idea for tumor immunotherapy.