Fig. 2
HRE enhances the expression and antitumor potency of HiCAR-T cells. a-c CAR expression under normoxia. CAR-, HiCAR- or chHE-HiCAR-T cells were cultured under normoxia for 24 h. Representative contour plots of CAR expression under normoxia (a); the results are presented as the mean ± SEM of three independent experiments with three healthy donors. Significant differences between HiCAR and chHE-HiCAR are indicated (NS: no significance, **: p < 0.01, ***: p < 0.001, ****: p < 0.0001, analyzed using one-way ANOVA) (b-c). d-f The impact of oxygen or CoCl2 levels on the CAR expression. The engineered T cells were cultured under 21% O2, CoCl2 or 1% O2 for 24 h. Representative contour plots of CAR expression under normoxia and hypoxia (d). These results are displayed as the mean ± SEM of three independent experiments with three healthy donors (e-f). g-h The effect of different oxygen levels on the cytotoxic properties of HiCAR-T cells towards tumor cells expressing high levels of HER2 (g) or low levels of HER2 (h). These results are displayed as the mean ± SEM of three independent experiments with three healthy donors, and significant differences between normoxia and hypoxia are indicated (*: p < 0.05, **: p < 0.01, ***: p < 0.001, ****: p < 0.0001, analyzed using a paired Student’s t-test). i-j The antitumor activity of HiCAR-T cells against tumors in vivo. The effects of CAR-, Hi-CAR or chHE-HiCAR- T cells on the growth of SKOV3 tumor cells (i). The impacts of CAR-, HiCAR- or chHE-HiCAR-T cells on the growth of NCI-H292 tumor cells expressing low levels of HER2 (j). The tumor volumes at different time points are displayed as the mean ± SEM (n = 5 mice/group), and significant differences between CAR-, HiCAR- or chHE-HiCAR-T cells and control T cells are indicated (*: p < 0.05, ****: p < 0.0001, analyzed using one-way ANOVA)