Human T cells engineered with an HLA-A2-restricted murine T-cell receptor targeting Glypican 3 effectively control human hepatocellular carcinoma in mice

Background & Aims: Glypican-3 (GPC3) is a promising target for T-cell therapy in hepatocellular carcinoma (HCC). While chimeric antigen receptor (CAR) T cells targeting GPC3 have demonstrated therapeutic efficacy, their effectiveness is limited by challenges such as low persistence and shedding of surface GPC3. Natural T-cell receptors (TCRs) may serve as an alternative, though identifying GPC3-specific TCRs within the endogenous repertoire is difficult. Approach & Results: We immunized HLA-A2 transgenic mice with an adenovirus expressing human GPC3, identifying a panel of TCRs that recognize the GPC3(522-530) epitope. We cloned three murine GPC3-TCRs (TCR-A, TCR-B, and TCR-C) and engineered primary human T cells (TCR-T). TCR-T cells effectively recognized GPC3 + HLA-A2 + human HCC cells, with recognition diminished by GPC3 silencing and HLA-A2 blockade. TCR-B-T and TCR-C-T cells showed the highest reactivity, with TCR-B-T cells exhibiting superior effector functions, proliferative capacity, and therapeutic efficacy in xenograft HCC models. Notable, TCR-B-T cells outperformed second-generation 41BB GPC3-specific CAR-T cells, attributed to lower exhaustion, enhanced proliferation, greater effector function, and improved resilience. Furthermore, mixed dosing of CAR-T and TCR-B-T cells was significantly more effective than staggered dosing of the same cell type, suggesting potential synergistic effects. Conclusion: Transgenic TCRs join forces with CARs, expanding the arsenal of GPC3-targeting receptors for HCC T-cell therapy.