PTGS2 and cancer: In 387 cells, the inhibitory effects of ERA and PE were partially reverted by the iron chelators deferoxamine mesylate (DFO) and ferrostatin (Fer) (Figures 6b and d), demonstrating that these small molecules exert their antitumor effect along the same pathways as described for other cancers.20, 21 PE upregulated PTGS2 (prostaglandin-endoperoxidase synthase 2) levels in GSC and this effect was reversible by VitE and DFO (Figure 6e).