title: Enhancement of 131I-mediated cytotoxicity by caffeine.
abstract: In cell culture, caffeine has been shown to enhance the lethality of DNA-damaging agents including ultraviolet rays, X-irradiation, and alkylating agents. We have previously reported a Phase I clinical trial demonstrating the feasibility of intraperitoneal radioimmunotherapy in patients with refractory ovarian cancer using 131I-labeled monoclonal antibody OC125. We are now exploring the possibility of using caffeine to enhance the toxicity of 131I-irradiation in target cells. As an in vitro model we tested this hypothesis using Chinese hamster ovary (CHO) cells exposed to 131I-labeled human serum albumin at various doses (4 to 70 microCi/ml) for 24 hr followed by 24 hr of incubation with caffeine. Cytotoxicity was measured by clonogenic survival and a nuclear fragmentation assay. The results show that caffeine, at a concentration of 7.7 mM, significantly enhances the cytotoxicity of 131I-irradiation.
authors.affiliation: Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: L L
authors.initials: LL
authors.lastname: Anderson
authors.forename: C C
authors.initials: CC
authors.lastname: Lau
authors.forename: E J
authors.initials: EJ
authors.lastname: Gracely
authors.forename: R S
authors.initials: RS
authors.lastname: Berkowitz
authors.forename: A I
authors.initials: AI
authors.lastname: Kassis
mesh_terms: D000818:Animals; D016466:CHO Cells / Q000187:drug effects* / Q000528:radiation effects*; D002110:Caffeine / Q000494:pharmacology*; D002470:Cell Survival; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007457:Iodine Radioisotopes / Q000494:pharmacology*
chemical_list: D007457:Iodine Radioisotopes; D002110:Caffeine