Genetically Engineered CLDN18.2 CAR-T Cells Expressing Synthetic PD1/CD28 Fusion Receptors Produced Using a...

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Advanced gastric cancer (GC) remains a significant clinical challenge with limited treatment options.
• Chimeric antigen receptor (CAR)-T cell therapy shows potential but faces hurdles in solid tumors, particularly immune suppression mediated by programmed cell death protein 1 (PD-1).
• Claudin18.2 (CLDN18.2) is a gastric-specific antigen identified as a promising target for GC therapy.

Purpose of the Study:

• To develop and evaluate synthetic CLDN18.2-targeted CAR-T cells for advanced gastric cancer.
• To engineer CAR-T cells that overcome the immunosuppressive tumor microenvironment by incorporating a PD-1/CD28 chimeric-switch receptor (CSR).
• To assess the in vitro and in vivo efficacy and safety of these novel CAR-T cell constructs.

Main Methods:

• Lentiviral vector technology was used to construct second-generation (CLDN18.2 CAR) and third-generation (CLDN18.2-PD1/CD28 CAR) CAR-T cells.
• In vitro assays measured cytokine secretion (IFN-γ, TNF-α) and cytotoxic activity against CLDN18.2-positive GC cells.
• In vivo studies utilized a xenograft GC model to evaluate antitumor effects and off-target toxicity.

Main Results:

• Both CAR-T cell types exhibited enhanced secretion of key cytokines, including interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α).
• CAR-T cells demonstrated improved killing ability against CLDN18.2-positive gastric cancer cells in vitro.
• In vivo, synthetic anti-CLDN18.2 CAR-T cells showed significant antitumor effects in a xenograft model, with the third-generation CLDN18.2-PD1/CD28 CAR exhibiting promising efficacy.

Conclusions:

• Synthetic anti-CLDN18.2 CAR-T cells possess potent antitumor activity against gastric cancer.
• The incorporation of a PD-1/CD28 CSR into a CLDN18.2-targeted CAR-T construct represents a promising strategy to enhance therapeutic efficacy in advanced gastric cancer by overcoming immune suppression.