A peptidic inhibitor for PD-1 palmitoylation targets its expression and functions

Area of Science:

• Cancer Biology
• Immunotherapy
• Molecular Mechanisms

Background:

• Programmed Cell Death protein 1 (PD-1) is a key target in cancer therapy.
• Existing antibody drugs targeting PD-1 have limitations, including low response rates and acquired resistance.
• There is a critical need for novel strategies to target PD-1 effectively.

Purpose of the Study:

• To investigate the role of palmitoylation in PD-1 regulation.
• To identify the enzyme responsible for PD-1 palmitoylation.
• To develop a peptide-based therapeutic targeting PD-1 palmitoylation.

Main Methods:

• Identification of the DHHC enzyme responsible for PD-1 palmitoylation.
• Analysis of the mechanism by which palmitoylation affects PD-1 protein stability and trafficking.
• Development and testing of a peptide inhibitor of PD-1 palmitoylation in a 3D culture system.

Main Results:

• Palmitoylation was identified as a key post-translational modification of PD-1, promoting its trafficking to recycling endosomes and preventing lysosomal degradation.
• PD-1 palmitoylation, distinct from PD-L1, enhances mTOR signaling and promotes tumor cell proliferation.
• Targeting PD-1 palmitoylation demonstrated significant anti-tumor effects in a three-dimensional culture model.

Conclusions:

• Palmitoylation is a novel mechanism regulating PD-1 stability and function.
• A rationally designed peptide inhibitor of PD-1 palmitoylation offers a promising new therapeutic avenue.
• This approach opens new possibilities for PD-1 inhibitors and combinatorial cancer immunotherapy strategies.