Fig. 4. mTERT-overexpressing ES cells are more resistant to stress-induced cell death. Undifferentiated ES cells were treated with various doses of H₂O₂ for 24 hours (A) and with cisplatin (B) or doxorubicin (C) for 12 hours, and cell death was determined by PI exclusion. Data represent means±s.d. from one of the three independent experiments in duplicate. (^*) indicates P<0.05 in a one-tailed unpaired Student's t test.