Fig. 3

Treatment of BT474 spheroids. BT474 spheroid were treated with either the mock or human epidermal growth factor receptor 2 (HER2)-CAR T cells at a ratio of 1:4 in agarose-coated wells for 24 h. A Optical and fluorescent images of the untreated and treated spheroids stained with calcein-AM (green) and ethidium homodimer-1 (red). Scale bar: 200 μm. Area size (B) and fluorescence intensity (C) of the untreated and treated spheroids. Data are expressed as the mean ± standard error of the mean (SEM) (n = 8). Student’s t-test: **p < 0.01, ***p < 0.001; NS: not significant. D Schematic describing the washing steps in agarose-coated wells after BT474 spheroids were treated with HER2-CAR T cells for 24 h. E Images of the untreated and treated spheroids with and without one or two repeated washings. Scale bar: 200 μm