Generation of reactive oxygen species by xanthine derivatives in MDA-MB-231 human breast cancer cells

Theophylline reduces cell number in MDA-MB-231 cells through mechanisms ove r and above phosphodiesterase inhibition. In the current study, we used an intracellular fluorescent dye to show that theophylline and, to a much grea ter extent, 3-isobutyl-1-methylxanthine, evoke the generation of reactive o xygen species and also sensitize the cells to insult by other oxidants. Xan thine derivatives may therefore offer novel strategies for antitumor therap eutics.