title: Azidothymidine (AZT) as a potential modifier of radiation response in vitro.
abstract: The potential effect of AZT as a thymidine analogue on radiation response in vitro was investigated. Two human cell lines (WiDr and HeLa) were used. The effect of 10 microM AZT on exponentially growing cells was studied after different exposure times (24, 48 and 72 h). The surviving fraction (clonogenic assay) or metabolic activity (MTT assay) after irradiation of AZT-exposed cells, was compared to unexposed irradiated controls. Flow cytometry was used to assess the cell-cycle effect of pre-exposure of exponentially growing cells to AZT. AZT had a radioprotective effect for all experimental time points as far as WiDr was concerned. For HeLa the effect was significant at 24 h. Cell-cycle analysis showed a significant accumulation in S-phase at 72 h for WiDr. For HeLa there was a significant accumulation in S-phase at 48 h. We conclude that under the reported experimental conditions, AZT as a thymidine analogue seems to reduce the cytotoxic effect of irradiation.
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
authors.forename: M L
authors.initials: ML
authors.lastname: Copaceanu
authors.forename: P A
authors.initials: PA
authors.lastname: Coucke
authors.forename: E
authors.initials: E
authors.lastname: Cottin
authors.forename: N
authors.initials: N
authors.lastname: Paschoud
authors.forename: R O
authors.initials: RO
authors.lastname: Mirimanoff
mesh_terms: D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D007155:Immunologic Factors; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D015215:Zidovudine / Q000494:pharmacology*
chemical_list: D007155:Immunologic Factors; D011837:Radiation-Protective Agents; D015215:Zidovudine