Neoepitope BTLAP267L-specific TCR-T cell immunotherapy unlocks precision treatment for hepatocellular carcinoma

OBJECTIVE: The high heterogeneity of hepatocellular carcinoma (HCC) renders traditional therapies unable to effectively activate the patient's immune system to combat tumors. Patients with advanced HCC and T cell functional deficiencies may benefit more from cellular immunotherapy, especially tumor neoepitope-targeted T cell receptor (TCR)-T cells. Neoepitopes with strong immunogenicity provide precise targets for HCC, further enhancing the efficacy of cellular immunotherapy. METHODS: A scalable workflow for identifying neoepitopes from 7 HLA-A*02:01-restricted patients with HCC was established based on whole exome sequencing and bioinformatics analyses, followed by identification of neoepitope-specific TCRs through tetramer-based screening and single-cell TCR cloning technology, which were further validated in the JC4 cell model. The cytotoxicity of CD8(+) TCR-T cells was evaluated in neoepitope-positive tumor cell lines or NCG mice. RESULTS: Ten specific neoepitopes were identified, among which neoepitope B and T lymphocyte attenuator(P267L) [BTLA(P267L) (SLNHSVIGL)] exhibited advantageous properties as a potential tumor target. Three TCRs (85-3, 126-5, and 52-3) were confirmed to specifically recognize the neoepitope BTLA(P267L), while no cross-recognition of irrelevant or wild-type epitopes was observed. Activated BTLA(P267L)-specific CD8(+) TCR-T cells released extensive perforin, granzyme B, IFN-γ, and TNF-α in vitro, thereby inducing strong cytotoxic effects against BTLA(P267L)-positive T2 or HCC cell lines. BTLA(P267L)-specific CD8(+) TCR-T cells mediated robust tumor regression due to long-lasting survival and released perforin without causing significant cytotoxic effects on normal organs in murine experiments. CONCLUSIONS: This preclinical study demonstrated the beneficial effects of neoepitope BTLA(P267L)-specific TCR-T cell immunotherapy, unlocking a novel strategy for personalized precision therapy in HCC.