Development of B7-H3 targeted CAR-T cells for renal cell carcinoma therapy: in vitro and in vivo efficacy.

Purpose: This study aims to develop chimeric antigen receptor (CAR)-T cells specifically targeting B7-H3-expressing renal cell carcinoma (RCC) and to evaluate the feasibility of B7-H3 CAR-T therapy for RCC.

Methods: We analyzed B7-H3 expression in RCC using bioinformatics approaches and confirmed it in tissues and cell lines through immunohistochemical staining and Western blot analysis. A lentiviral vector containing a B7-H3 specific CAR was constructed and transfected into human T cells, with CAR expression verified by flow cytometry. Cytotoxic efficacy was evaluated in co-culture experiments, measuring the production of interferon-gamma (IFN-γ), interleukin-2 (IL-2), granzyme B, and lactate dehydrogenase (LDH) release. Xenograft models in nude mice were used to evaluate tumor growth inhibition by B7-H3 CAR-T cells.

Results: B7-H3 was significantly expressed in RCC and associated with poor prognosis. Elevated levels of B7-H3 expression were validated in both RCC tissues and cell lines. A B7-H3-specific CAR-T cell was developed, achieving a CAR transduction efficiency of 39.85%, as assessed by flow cytometry. In vitro co-culture assays demonstrated that the CAR-T cells exhibited substantial cytotoxic activity against RCC cell lines, with this activity positively correlating with the effector-to-target ratio. Furthermore, the secretion levels of IFN-γ, IL-2, granzyme B, and LDH were significantly increased compared to the control groups. In vivo experiments further confirmed that B7-H3 CAR-T cells significantly inhibited tumor growth.

Conclusion: The current study suggests that B7-H3 CAR-T cells exhibit significant efficacy in targeting and eliminating RCC cells, indicating a promising cellular immunotherapy approach for RCC treatment.