Chia-Wei Li1, Seung-Oe Lim1,12, Ezra M. Chung11, Yong-Soo Kim11, Andrew H. Park11, Jun Yao1, Jong-Ho Cha1,4, Weiya Xia1, Li-Chuan Chan1,5, Taewan Kim1, Shih-Shin Chang1, Heng-Huan Lee1, Chao-Kai Chou1, Yen-Liang Liu6, Hsin-Chih Yeh6, Evan P. Perillo6, Andrew K. Dunn6, Chu-Wei Kuo7,8, Kay-Hooi Khoo8, Jennifer L. Hsu1,9, Yun Wu2, Jung-Mao Hsu1, Hirohito Yamaguchi1, Tzu-Hsuan Huang1, Aysegul A. Sahin2, Gabriel N. Hortobagyi3, Stephen S. Yoo11, Mien-Chie Hung1,5,9,10
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Unit 108, 1515 Holcombe Boulevard, Houston, TX 77030, USA
- Department of Pathology
- Department of Breast Medical Oncology The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
- Core Facilities for Protein Structural Analysis
- Institute of Biological Chemistry Academia Sinica, Taipei 115, Taiwan
- Graduate Institute of Biomedical Sciences and Center for Molecular Medicine, China Medical University, Taichung 404, Taiwan
- Department of Biotechnology, Asia University, Taichung 413, Taiwan
- STCube Pharmaceuticals, Inc., 401 Professional Drive, Suite 250, Gaithersburg, MD 20879, USA
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
Protein glycosylation provides proteomic diversity in regulating protein localization, stability, and activity; it remains largely unknown whether the sugar moiety contributes to immunosuppression. In the study of immune receptor glycosylation, we showed that EGF induces programmed death ligand 1 (PD-L1) and receptor programmed cell death protein 1 (PD-1) interaction, requiring β-1,3-N-acetylglucosaminyl transferase (B3GNT3) expression in triple-negative breast cancer. Downregulation of B3GNT3 enhances cytotoxic T cell-mediated anti-tumor immunity. A monoclonal antibody targeting glycosylated PD-L1 (gPD-L1) blocks PD-L1/PD-1 interaction and promotes PD-L1 internalization and degradation. In addition to immune reactivation, drug-conjugated gPD-L1 antibody induces a potent cell-killing effect as well as a bystander-killing effect on adjacent cancer cells lacking PD-L1 expression without any detectable toxicity. Our work suggests targeting protein glycosylation as a potential strategy to enhance immune checkpoint therapy.
CovalX Technology Used (Click each option to learn more)
The epitopes of mouse monoclonal gPD-L1 antibodies STM004 and STM108 were both mapped. 5 μl of the antigen sample was combined with 5 μl of the antibody sample, giving a final concentration of 2 μM/1 μM. Cross-linkers and other chemicals were added to the solution before allowing crystallization. The samples were analyzed using the CovalX HM4 detection system.