Fig. 6: NSC80997 boosts antibody-dependent cellular cytotoxicity (ADCC) of Tn-specific mAbs 6C5 and 5E5.

a Cell surface binding of mAbs 5E5 (top) and 6C5 (bottom) to HEK^WT, HEK^{KO FXYD5} cells, and HEK^WT cells stably expressing membrane MUC1 reporter protein (HEK^MUC1) treated with increasing concentrations of NSC80997 for 24 h. Antibody binding was measured by flow cytometry and data is shown as mean MFI ± SEM (arbitrary units) of three independent experiments. b Schematic illustration of ADCC assay. HEK^MUC1 cells were treated with 10 µM NSC80997 or DMSO for 4 h, washed, and re-seeded. Monoclonal antibodies directed against Tn-MUC1 (5E5) and Tn-FXYD5 (6C5) were added to the HEK cells 20 min prior to addition of CFSE-labeled peripheral blood lymphocytes (PBLs) at 5:1, 10:1, and 20:1 effector to target (E:T) ratios. Isotype (mouse IgG) treated cells served as control. After overnight incubation, all cells were harvested and labeled with viability dye and analyzed by flow cytometry. c Bar diagrams show percentage lysis normalized to isotype control, of DMSO or NSC80997 treated HEK^MUC1 cells induced by 5E5 (top) or HEK^WT cells induced by 6C5 (bottom) mAbs. Data is presented as mean percentage lysis compared to control ± SEM from 3 independent experiments. *P < 0.05 (t-test).