Construction of HER2-specific CAR-T cells and in vitro analysis of their activity to suppress tumor cell growth

Abstract

CAR-T cell therapy that targets surface antigens to kill tumor cells specifically has recently become another cornerstone in tumor immunotherapy. In this study, a lentiviral expression plasmid of CAR targeting human epidermal growth factor receptor 2 (HER2) was constructed by genetic engineering. The recombinant plasmid was co-transfected with other packaging plasmids into HEK293T cells by calcium phosphate precipitation to generate lenti-car, which are CAR lentiviral particles. HER2-specific CAR-T cells were obtained by transducing human peripheral blood mononuclear cells with lenti-car. Their specific inhibitory effects on HER2-positive and HER2-negative tumor cells were analyzed in vitro. The constructed CAR-T cells were specifically activated by HER2-expressing tumor cells as indicated by secretion of IFN-γ and IL-2. The inhibitory rate on HER2-positive SK-OV-3 cell line was (58.47±1.72)%, significantly higher than that on the mock-treated control group (P<0.05). The inhibitory rate on HER2-negative K562 cell lines was (11.74±2.37)%, which was not significantly different from that on the control group (P>0.05). Furthermore, when we transfected a HER2-expressing vector into K562, the inhibitory rate increased to (30.41±7.59)%, which was higher than that on HER2-negative K562 (P<0.05). Thus, the constructed second-generation HER2-specific CAR-T cells specifically suppressed growth of tumor cells overexpressing HER2 protein, suggesting that HER2-specific CAR-T cells might prove useful for immunotherapy of HER2-positive cancer.