Identification of an HLA-A11:01-restricted neoepitope of mutant PIK3CA and its specific T cell receptors for cancer immunotherapy targeting hotspot driver mutations

• Published in: Cancer Immunology, Immunotherapy : CII Vol. 73; no. 8; p. 150
• Main Authors: Shen, Meiying, Chen, Siyin, Han, Xiaojian, Hao, Yanan, Wang, Junfan, Li, Luo, Chen, Tong, Wang, Bozhi, Zou, Lin, Zhang, Tong, Zhang, Wanli, Han, Xiaxia, Wang, Wang, Yu, Haochen, Li, Kang, Liu, Shengchun, Jin, Aishun
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 04.06.2024; Springer Nature B.V
• Subjects: Antigens; Avidity; Cancer; Cancer immunotherapy; Cancer Research; CD8 antigen; Cell activation; Cell therapy; Cytokines; Cytotoxicity; Histocompatibility antigen HLA; Immunogenicity; Immunology; Immunotherapy; Leukocytes (mononuclear); Lymphocytes; Lymphocytes T; Medicine; Medicine & Public Health; Mutants; Mutation; Mutation hot spots; Neoantigens; Oncology; Peripheral blood mononuclear cells; T cell receptors; Tumor cell lines; Tumors; HLA-A11:01; Anti-tumor immunotherapy; Engineering TCR-T; Neoantigen
• ISSN: 1432-0851; 0340-7004; 1432-0851
• DOI: 10.1007/s00262-024-03729-y

Hotspot driver mutations presented by human leukocyte antigens might be recognized by anti-tumor T cells. Based on their advantages of tumor-specificity and immunogenicity, neoantigens derived from hotspot mutations, such as PIK3CA H1047L , may serve as emerging targets for cancer immunotherapies. NetMHCpan V4.1 was utilized for predicting neoepitopes of PIK3CA hotspot mutation. Using in vitro stimulation, antigen-specific T cells targeting the HLA-A*11:01-restricted PIK3CA mutation were isolated from healthy donor-derived peripheral blood mononuclear cells. T cell receptors (TCRs) were cloned using single-cell PCR and sequencing. Their functionality was assessed through T cell activation markers, cytokine production and cytotoxic response to cancer cell lines pulsed with peptides or transduced genes of mutant PIK3CA . Immunogenic mutant antigens from PIK3CA and their corresponding CD8 + T cells were identified. These PIK3CA mutation-specific CD8 + T cells were subsequently enriched, and their TCRs were isolated. The TCR clones exhibited mutation-specific and HLA-restricted reactivity, demonstrating varying degrees of functional avidity. Identified TCR genes were transferred into CD8 + Jurkat cells and primary T cells deficient of endogenous TCRs. TCR-expressing cells demonstrated specific recognition and reactivity against the PIK3CA H1047L peptide presented by HLA-A*11:01-expressing K562 cells. Furthermore, mutation-specific TCR-T cells demonstrated an elevation in cytokine production and profound cytotoxic effects against HLA-A*11:01 + malignant cell lines harboring PIK3CA H1047L . Our data demonstrate the immunogenicity of an HLA-A*11:01-restricted PIK3CA hotspot mutation and its targeting therapeutic potential, together with promising candidates of TCR-T cell therapy.