Figure 2

Isobolographic analysis of apoptosis induction after combined treatment. Apoptosis was determined by microscopic evaluation of Hoechst stained cell nuclei 48 h after combined treatment. Envelopes of additivity were calculated with data of 3 independently performed experiments. Datapoints below the curves resemble a synergistic effect, datapoints between the curves demonstrate an additive effect and above the curves a subadditive response of combined treatment. A : tumour cells were treated simultaneously with 10 Gy and 0,1 ng/ml TRAIL. B: cells were irradiated with 10 Gy 12 h prior to treatment with 0,1 ng/ml TRAIL.