Figure 4.

hERG channels delay recovery from radiation-induced release from S and G₂/M arrest in K562 cells. (A) Flow cytometry histograms depicting the propidium iodide fluorescence (Nicoletti staining) of K562 cells irradiated (0 or 5 Gy) and post-incubated (48 h) with vehicle (black) or hERG inhibitor E4031 (3 µM). (B) Time course of radiation (5Gy)-induced changes in cell cycle progression in the absence (vehicle, open circles) and presence of E4031 (3 µM, closed triangles). Shown are mean (± SE, n = 21) percentages of cells residing in G₁ (left), S (middle), or G₂ (right) phase of cell cycle 0, 24, 48, and 72 h after irradiation. (C) Mean percentage (± SE, n = 27) of irradiated (0 or 5 Gy) K562 cells residing 48 h after irradiation in G₁ (left), S (middle), or G₂ (right) phase of cell cycle. Cells were pre- and post-incubated with vehicle (open bars) or E4031 (3 µM, closed bars). * indicates p ≤ 0.05, two-tailed t-test in (B) and ANOVA in (C).