Figure 5.

Radiotherapy alone and in combination with hyperthermia regardless of the treatment sequence induces apoptosis in MCF-7 breast cancer cells. The percentage of necrotic MCF-7 cells are shown in graphs (a) 24 h, (b) 48 h, (c) 72 h and (d) 120 h after the treatment. The percentage of apoptotic MCF-7 cells is shown in graphs (e) 24 h, (f) 48 h, (g) 72 h and (h) 120 h after the treatment. MCF-7 cells were irradiated 2 times with 5 Gy (RT) or treated with HT of different temperatures (39 °C, 41 °C, 44 °C) and combinations of both, either HT followed by RT (HT (39 °C, 41 °C, 44 °C) + RT) or vice versa (RT + HT (39 °C, 41 °C, 44 °C)). The time interval between HT and RT was less than 2 h. The cell death forms were analyzed by AnxV/PI staining using multicolor flow cytometry. Mean ± SD are presented from at least five independent experiments. Statistical significance is calculated by using a Kruskal–Wallis test with Dunn’s correction to compare the percentage of necrotic and apoptotic cells of each group of a respective temperature to the untreated control, and a Mann–Whitney U test to compare the different sequences of HT and RT. * (p < 0.1), ** (p < 0.01) for Kruskal–Wallis test with Dunn’s correction.