1. Department of Systems Biomedical Sciences, School of Medicine, Jinan University, Guangzhou, China.
2. Guangdong-Hong Kong-Macau Great Bay Area Geroscience Joint Laboratory, School of Medicine, Jinan University, Guangzhou, China.
3. Guangzhou Geriatric Hospital, Guangzhou, China.
4. Collaborative Innovation Center for Civil Affairs of Guangzhou, Guangzhou, China.
5. Department of Oncology, Research Center of Cancer Diagnosis and Therapy, the First Affiliated Hospital, Jinan University, Guangzhou, China.
6. Department of Microbiology and Immunology; Institute of Geriatric Immunology; School of Medicine, Jinan University, Guangzhou, China.
7. School of Life Science & Technology, China Pharmaceutical University, Nanjing, China.
* These authors contributed equally: Bei Zhang, Zhiyao Ren, Jianfu Zhao, Yue Zhu.
Background: Advanced non-small cell lung cancer (NSCLC) is the most common type of lung cancer with poor prognosis. Adoptive cell therapy using engineered T-cell receptors (TCRs) targeting cancer-testis antigens, such as Melanoma-associated antigen 3 (MAGE-A3), is a potential approach for the treatment of NSCLC. However, systematic analysis of T cell immune responses to MAGE-A3 antigen and corresponding antigen-specific TCR is still lacking.
Methods: In this study, we comprehensively screened HLA-A2 restricted MAGE-A3 tumor epitopes and characterized the corresponding TCRs using in vitro artificial antigen presentation cells (APC) system, single-cell transcriptome and TCR V(D)J sequencing, and machine-learning. Furthermore, the tumor-reactive TCRs with killing potency was screened and verified.
Results: We identified the HLA-A2 restricted T cell epitopes from MAGE-A3 that could effectively induce the activation and cytotoxicity of CD8+ T cells using artificial APC in vitro. A cohort of HLA-A2+ NSCLC donors demonstrated that the number of epitope specific CD8+ T cells increased in NSCLC than healthy controls when measured with tetramer derived from the candidate MAGE-A3 epitopes, especially epitope Mp4 (MAGE-A3: 160-169, LVFGIELMEV). Statistical and machine-learning based analyses demonstrated that the MAGE-A3-Mp4 epitope-specific CD8+ T cell clones were mostly in effector and proliferating state. Importantly, T cells artificially expressing the MAGE-A3-Mp4 specific TCRs exhibited strong MAGE-A3+ tumor cell recognition and killing effect. Cross-reactivity risk analysis of the candidates TCRs showed high binding stability to MAGE-A3-Mp4 epitope and low risk of cross-reaction.
Conclusions: This work identified candidate TCRs potentially suitable for TCR-T design targeting HLA-A2 restricted MAGE-A3 tumor antigen.
Keywords: NSCLC, MAGE-A3, Epitope-specific TCR, Cancer immunotherapy