title: The effect of theophylline upon the activity of methotrexate and 5'-fluorouracil in HeLa cell cultures.
abstract: The cytotoxic activity of methotrexate upon HeLa cells was shown to be enhanced by the addition of 0.1 mM theophylline. Cell cultures receiving the combination of theophylline and methotrexate displayed an over two-fold increase in the loss of viable cells when compared to cultures receiving methotrexate alone. In contrast, theophylline treatment of HeLa cells did not enhance the cytotoxic activity of 5'-fluorouracil. The reasons for this observation remain unexplained. Theophylline itself at a concentration of 0.1 mM did not display any observable toxic effects upon the HeLa cell cultures.
mesh_terms: D004357:Drug Synergism; D005472:Fluorouracil / Q000494:pharmacology*; D006367:HeLa Cells / Q000187:drug effects*; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology*; D012044:Regression Analysis; D013806:Theophylline / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D013806:Theophylline; D005472:Fluorouracil; D008727:Methotrexate