Detection and cytotoxicity of cisplatin-induced superoxide anion in monolayer cultures of a human ovarian cancer cell line.
Superoxide anions (O2-) generated by cisplatin [cis-diamminedichloroplatinum (II), DDP] were determined by measuring the chemiluminescence from the luminescence probe, 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (methyl Cypridina luciferin analog, MCLA), in monolayer cultures of a human ovarian cancer cell line (A2780) in physiological saline at pH 7.0. In a time-course study, chemiluminescence of MCLA (C-MCLA) showed a peak level at 10 min and a background level at 60 min after the addition of DDP. The intensity of C-MCLA increased with increasing concentrations of DDP or MCLA in a limited concentration range, and was significantly correlated (r = 0.960) with the number of A2780 cells. DDP-induced C-MCLA was completely inhibited by the addition of the O2- scavenger, superoxide dismutase (SOD). However, SOD did not decrease DDP cytotoxicity in terms of clonogenic cell survival. These findings suggest that DDP generates extracellular O2-, probably by interaction with the cellular membrane in A2780 cells, and O2- does not lead to cellular damage.
Masuda
H
H
Department of Surgery, Kyushu Dental College, Japan.
Tanaka
T
T
Tateishi
M
M
Naito
M
M
Tamai
H
H
D000970:Antineoplastic Agents / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007093:Imidazoles; D008163:Luminescent Measurements; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D011719:Pyrazines; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000032:analysis / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D007093:Imidazoles; D011719:Pyrazines; D013481:Superoxides; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one; D013482:Superoxide Dismutase; D002945:Cisplatin