Comparison of effects of PTS2, PT, DDP and ADM on KB cell viability. (A) PTS2, PT, DDP and ADM (2.5 μg/ml) were added to KB cells, and assayed using MTT to determine cell viability after incubation for the indicated times. (B) In KB cells exposed to the indicated amounts of PTS2, PT, DDP and ADM for 36 h, cell viability was assayed using MTT. Data are means ± S.D. from 3 independent experiments. **P < 0.01; ***P < 0.001 compared with untreated controls. (C) KB cells were treated with 2.5 μg/ml of PTS2, PT, and DDP for 36 h, stained with Annexin V/PI, and examined with flow cytometry. Data are means ± S.D. ***P < 0.001, compared with viability of untreated cells. ###
P < 0.001, compared with viability of PTS2-treated cells. Results are representative of 3 independent experiments.