Fig. 3From: Targeting anti-apoptotic Bcl-2 by AT-101 to increase radiation efficacy: data from in vitro and clinical pharmacokinetic studies in head and neck cancerSynergistic interaction between radiation and AT-101. Figure 3a and b illustrate apoptosis induction in two HNSCC lines after radiation, AT-101 and their combination at the indicated doses. For the combination experiments, AT-101 was administered 24 h after radiation. These graphs represent the results of at least 3 independent experiments performed in duplo. Figure 3c shows an isobolographic analysis of the combined effect of 29 % apoptosis induced by 10 Gy radiation and 15 μM AT-101. The same level of apoptosis can be induced by 18.4 Gy of radiation or 44 μM of AT-101, respectively. The combination point (▲) below the envelope of additivity indicates a synergistic interaction between both stimuli. Note that in all conditions shown, the CI that refers to the combination index, is smaller than 1.0, indicating synergy as wellBack to article page