Fig. 4

MS-275 enhances the efficacy of immunotherapies targeting the NKG2A–HLA-E axis in vitro. A-B Luciferase-engineered TT150630 and TT190326 cell lines were treated with DMSO or 1µM MS-275 for 2 days and cocultured with NK-92MI cells for 4 h at a 1:1 ratio. The NK-92MI cells were preincubated with control IgG (50 μg/ml), tiragolumab (50 μg/ml) or monalizumab (50 μg/ml) for 1 h at 37 °C before being cocultured with the tumor cells and the NK-92MI cells. The percentage (%) of cells undergoing NK cell-induced cytotoxicity was calculated and plotted. Statistical significance was assessed via one-way ANOVA, with *p < 0.05 and **p < 0.01. C-D TT190326 and TT150630 cells were treated with MS-275 (1µM) for 2 days, stained with calcein AM, and cocultured with NK-92MI cells for 4 h in 96-well plates at a 1:1 ratio. The NK-92MI cells were preincubated with control IgG (50 μg/ml), tiragolumab (50 μg/ml) or monalizumab (50 μg/ml) for 1 h at 37 °C before being cocultured with the tumor cells and the NK-92MI cells. Fluorescence images were captured using an inverted microscope (left). The percentage (%) of cells undergoing NK cell-induced cytotoxicity was calculated and plotted (right). Statistical significance was assessed via one-way ANOVA, with *p < 0.05 and **p < 0.01. Scale bars, 500 μm.