Patient-Derived Organoid Modeling of Glypican-3 CAR-T Responses in Hepatocellular Carcinoma

Glypican-3 (GPC3)-targeted chimeric antigen receptor T (CAR-T) cell therapy is a promising approach for hepatocellular carcinoma (HCC), but marked interpatient variability and antigen heterogeneity limit its broader application. Here, we established a patient-derived organoid (PDO)-based platform to functionally evaluate autologous GPC3-targeted CAR-T cell activity in HCC. HCC PDOs preserved key histologic features and heterogeneous GPC3 expression patterns of the original tumors. In co-culture assays, CAR-T cell cytotoxicity was associated with GPC3 expression levels and was accompanied by IFN-γ and IL-2 release, supporting the feasibility of using PDOs for functional assessment of CAR-T cell sensitivity. We further found that matrix conditions strongly influenced organoid architecture, viral transduction, CAR-T cell infiltration, and killing efficiency, with lower Matrigel concentrations providing a more permissive setting for functional assessment. Importantly, in GPC3-low PDOs, pretreatment with the DNA methyltransferase inhibitor 5-azacytidine (5-AZA) reduced DNA methyltransferase 3 alpha (DNMT3A) expression, increased surface GPC3 expression, and significantly enhanced CAR-T-mediated cytotoxicity. Together, these findings provide proof-of-concept evidence supporting the use of HCC PDOs as a patient-derived platform for modeling selected determinants of GPC3-targeted CAR-T cell activity and for exploring combination strategies to improve therapeutic efficacy.