title: Characterization of conditions in which dipyridamole enhances methotrexate toxicity in L1210 cells.
abstract: In vitro studies in exponentially growing L1210 cells utilizing DNA flow cytometry and cell proliferation measurements indicate enhancement of methotrexate effects by Dipyridamole provided: Methotrexate concentrations exceed those required to shut off maximally de novo pathways of purine and pyrimidine synthesis (i.e. 30 nM for 48 h), and Dipyridamole concentrations exceed 3 microM. In 10% fetal calf serum, this concentration inhibits tritiated thymidine uptake by about 80%. These data should prove helpful in the planning of clinical studies with dipyridamole or other inhibitors of nucleoside transport used to potentiate inhibitors of de novo pathways.
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004176:Dipyridamole / Q000008:administration & dosage*; D004357:Drug Synergism; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000378:metabolism; D007939:Leukemia L1210 / Q000188:drug therapy*; D008727:Methotrexate / Q000008:administration & dosage*; D051379:Mice; D013936:Thymidine / Q000378:metabolism
chemical_list: D007042:Hypoxanthines; D019271:Hypoxanthine; D004176:Dipyridamole; D013936:Thymidine; D008727:Methotrexate