title: Trifluoperazine stimulates ionizing radiation induced cell killing through inhibition of DNA repair.
abstract: The effect of trifluoperazine (TFP), a phenothiazine derivative antipsychotic drug, on ionizing radiation (IR) induced cell killing through inhibition of DNA repair was investigated in human cell lines. In clonogenic survival assay, TFP augmented IR induced cell killing. Also, TFP enhanced micronucleus formation in irradiated human lymphocytes. The effect of TFP and other known DNA repair inhibitors like wortmannin and caffeine, on irradiated cells, was compared by MTT assay. On the other hand, TFP failed to increase the toxicity induced by H2O2. Repair of DNA double strand breaks induced by IR was markedly inhibited by TFP, as determined by field inversion gel electrophoresis (FIGE). Further, TFP increased radiation induced apoptosis, which was accompanied by enhanced G2/M arrest. Thus, our results strongly suggest that TFP inhibits repair of DNA damage induced by IR, which significantly implicates the possibility of using TFP as an adjuvant to radiotherapy.
authors.affiliation: Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India.
authors.forename: Sudeshna
authors.initials: S
authors.lastname: Gangopadhyay
authors.forename: Parimal
authors.initials: P
authors.lastname: Karmakar
authors.forename: Uma
authors.initials: U
authors.lastname: Dasgupta
authors.forename: Anindita
authors.initials: A
authors.lastname: Chakraborty
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D004260:DNA Repair / Q000187:drug effects* / Q000528:radiation effects*; D005720:Gamma Rays; D006801:Humans; D015162:Micronucleus Tests; D011839:Radiation, Ionizing; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D014268:Trifluoperazine / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D011838:Radiation-Sensitizing Agents; D014268:Trifluoperazine