Conditioned medium containing ES + Tum reduced proliferation and induced apoptosis in G55 glioma cells in vitro . (A) G55 cells were cultivated in CM from PAE WT cells, and in CM containing ES or Tum or ES + Tum. Cell numbers were determined after a culture period of 24 and 48 hours. Bars represent the means ± SE (n = 3); * on bars indicates significant differences vs. WT; * on connecting lines indicates significant differences between respective groups (p < 0.05). (B) Phase contrast micrographs of G55 cells after a culture period of 24 hours in CM from PAE-WT cells or CM containing ES or Tum or ES + Tum. (C) Quantification of apoptotic G55 cells after cultivation in CM from PAE WT cells or CM containing ES or Tum or ES + Tum using flow cytometric analysis after FITC-conjugated annexin-V and PI staining.