Synergistic Antitumor Efficacy of Radiofrequency Ablation Combined With TROP2-CAR-T Cells in a Xenograft Mouse Model of Lung Adenocarcinoma.

Abstract

BACKGROUND: Lung adenocarcinoma (LUAD) is highly relapsed and responds poorly to chimeric antigen receptor (CAR)-T therapy due to antigenic heterogeneity and the immunosuppressive microenvironment. Trophoblast cell-surface antigen 2 (TROP2), overexpressed in LUAD and linked to poor prognosis, is a promising target. Radiofrequency ablation (RFA) can cause direct tumor necrosis, trigger immunogenic cell death, and enhance immune infiltration through antigen secretion; however, it often fails to eradicate residual tumors. Therefore, combining RFA with CAR-T-cell therapy may offer a new and synergistic therapy against LUAD. OBJECTIVE: This study examined the cytotoxicity of TROP2-directed CAR-T cells against LUAD in vitro and observed their therapeutic efficacy and safety in combination with RFA in vivo. METHODS: Third-generation TROP2-CAR-T cells were developed and characterized for transduction efficiency, CD4/CD8 ratio, and proliferative capacity. Their antigen-specific cytotoxicity against TROP2target cells was observed using a luciferase-based assay and cytokine analysis. An A549-TROP2-Luc xenograft model was developed to examine the therapeutic effects of RFA, TROP2-CAR-T monotherapy, and their combination. Tumor suppression, Ki67/TUNEL assays, and immunohistochemical (IHC) analyses were performed to evaluate efficacy and safety. RESULTS: TROP2-CAR-T cells showed efficient transduction and potent, antigen-dependent cytotoxicity with significant cytokine secretion in vitro. In vivo, both RFA and TROP2-CAR-T therapy suppressed tumor growth, and their combination showed a synergistic antitumor effect without hepatic or renal toxicity. CONCLUSION: The combination of RFA and TROP2-CAR-T therapy demonstrates enhanced antitumor efficacy and improved safety profile in LUAD, highlighting a promising combinatorial immunotherapeutic approach.