A DNA-Mediated Lysosomal Degradation Strategy for Targeted Degradation of PD-L1 Protein

Area of Science:

• Immunology
• Molecular Biology
• Drug Development

Background:

• Programmed cell death ligand 1 (PD-L1) expression allows tumors to evade T-cell immune surveillance.
• PD-L1 cell surface levels are critical for the efficacy of PD-L1-targeted immune checkpoint blockade therapy.

Purpose of the Study:

• To develop a novel strategy for PD-L1 degradation using scavenger receptors (SRs) to enhance cancer immunotherapy.
• To create a bifunctional compound that targets both SRs and PD-L1 for lysosomal degradation.

Main Methods:

• Utilized click chemistry to conjugate the PD-L1 inhibitor BMS-202 with dendritic DNA scaffolds, forming the bifunctional compound PBL1.
• Employed SRs' trafficking capabilities to direct PD-L1 to lysosomes for degradation.
• Validated PBL1 efficacy and specificity in A549 cells and zebrafish models.

Main Results:

• PBL1 effectively induces PD-L1 degradation both in vitro and in vivo.
• Significantly reduced off-target toxicity compared to traditional PD-L1 inhibitors.
• Demonstrated efficacy and specificity of PBL1 in cellular and animal models.

Conclusions:

• SRs-mediated lysosomal degradation of PD-L1 is a promising strategy for cancer immunotherapy.
• PBL1 offers a safer and more targeted alternative to existing PD-L1 inhibitors.
• This approach enhances the potential of immune checkpoint blockade therapy.