Development of a new EGFR-VHH-CAR T-cell therapy for treatment of esophageal squamous cell carcinoma

Abstract

Esophageal squamous cell carcinoma (ESCC), a primary form of esophageal cancer, is characterized by poor outcomes and limited treatment options. Targeting EGFR with chimeric antigen receptor-modified T cells (EGFR CAR-T) has emerged as a promising therapeutic approach for ESCC. Utilizing nanobodies enhances the specificity of antigen recognition and has become a popular method in CAR-T cell therapy. In this study, we introduced an EGFR-specific nanobody, EGFR-VHH-7D12, into the receptor binding domain of EGFR CAR-T cells and incorporated human interleukin 21 (hIL-21) to boost the efficacy of these cells. Our findings show that EGFR-VHH-7D12-equipped CAR-T cells can accurately target and eliminate EGFR-positive esophageal cancer cells both in vitro and in animal models. The addition of hIL-21 not only increased the proliferation of CAR-T cells but also led to a higher formation of memory T cell subsets in vitro. Furthermore, the presence of hIL-21 in these CAR-T cells resulted in increased expression of IFN-gamma when cultured with various human esophageal cancer cell lines (KYSE-30, KYSE-150, and KYSE-510) in vitro. Notably, CAR-T cells expressing both EGFR-VHH-7D12 and hIL-21 showed superior anti-tumor activity in a KYSE-150 xenograft mouse model. Our results indicate that the combined expression of hIL-21 in 7D12-CAR-T cells significantly enhances their anti-tumor capabilities, making them a highly promising option for ESCC treatment.