Fig. 2

Hyperthermia promotes synergistic and additive effects with radiation and temozolomide in GL261 and SD3 GBM cell lines. Cell viability curves showing the effects of escalating doses of ionizing radiation (IR) or temozolomide (TMZ) alone (black circles) or in combination with hyperthermia (HT) pretreatment (gray squares) in GL261 (A, B) and SD3 (C, D) GBM cell lines. HT doses are represented in terms of thermal dose at cumulative equivalent minutes at 43 C (CEM43). (A) GL261 cells treated with 17.86 min HT combined with escalating RT doses (2–8 Gy). (B) GL261 cells treated with 17.86 min HT combined with escalating TMZ doses (12.5–100 µM). (C) SD3 cells treated with 26.26 min HT combined with escalating RT doses (3–10 Gy). (D) SD3 cells treated with 13.68 min HT combined with escalating TMZ doses (1–9 µM). Tabulated values below each graph show the combination index (CI) and dose reduction index (DRI) for each combination. Separate HT monotherapy dose escalation studies were performed simultaneously (data not shown) to determine CI. Per Chou T.C. et al. (2006), CI values are interpreted as indicated in the included textbox (E). Dose reduction index (DRI) values represent the fold reduction in dose required when using the combination to achieve the same effect as the single agent alone. Error bars represent standard error of the mean.