4.

Effects of H₂O₂-treatment (30 mM, 3 min) on cell cycle profiles and cell viability of HCT116 p53⁻/⁻ cells after 6 hrs and 24 hrs, with and without TSA (200 ng/ml, 6 hrs) pre-treatment. (A) H₂O₂ induces G₂/M arrest in HCT116 p53⁻/⁻ cells after 24 hrs while TSA induces a slight G₂/M stop.(B) Annexin-V measurement shows that neither H₂O₂ nor TSA induce a significant apoptosis. (C) Western Blotting of caspase 3 confirms the observed Annexin-V results. (D) Time-dependent effects (6 hrs and 24 hrs) of TSA, H₂O₂, and their combined treatment on cell cycle progression and apoptosis induction. Above the line, data of FACS analysis (in%) are shown and below the line apoptotic cells (in%) measured in the Annexin-V-Assay are given.