Microphysiological Solid Tumor Models in Hydrogel Beads for CAR T Cell Immunotherapy Evaluation

This study establishes a tunable 3D micrometastatic tumor model using PEGDA hydrogel beads for in vitro evaluation of chimeric antigen receptor (CAR) T cell therapy. The system replicates soft-tissue microenvironments (elastic modulus 0.3–0.6 kPa) by combining prostate stem cell antigen (PSCA)-expressing prostate cancer cells and fibroblast activation protein (FAP)-producing stromal cells in droplet-fabricated PEGDA microbeads. Co-culture modulated spheroid morphology, FAP secretion, and extracellular matrix remodeling, yielding tumor microstructures that recapitulate in vivo metastasis and immunosuppressive conditions. CAR T cell infiltration studies revealed that dual targeting of PSCA and FAP antigens significantly improved migration and cytotoxicity compared to single-antigen strategies, mirroring clinical resistance mechanisms in solid tumors.