[Effect of inducible nitric oxide synthase on tumour cells sensitivity to mitomycin C analogue 629 in vitro].
OBJECTIVE
To examine the effect of inducible nitric oxide synthase (iNOS) on tumour cells chemosensitivity to mitomycin C (MMC) analogue 5-aziridinyl-3-hydroxyl-1-methylindole-4,7-dione (629) in vitro, and elucidate the possible role of iNOS in the metabolism of 629.


METHODS
Human sarcoma cells (HT1080) and its iNOS gene transfected clones (iNOS9, iNOS12) were exposed to 629 at concentrations of 1 nmol x L(-1) - 100 micromol x L(-1). 3-[4, 5-Dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide (MTT) assay, agarose electrophoresis and flow cytometric analysis were used to determine cell sensitivity, deoxyribonucleic acid (DNA) damage and the change of cell cycle in above process, respectively. All experiments were performed both in air and under hypoxia parallelly.


RESULTS
629 was more toxic than MMC, and enhanced cytotoxicity under hypoxia, which resulted in cell necrosis. Sixteen hours after treated with 629, HT1080 cells and related iNOS-transfected clone cells were obviously blocked in G2/M phase.


CONCLUSIONS
iNOS plays dual roles in 629 metabolism, enhancing or decreasing the cytoxicity of 629 depending on the intracellular oxygen pressure P(O2), which caused higher cytotoxicity to hypoxia cells of 629 with the increasing of iNOS activity.
Kong
Zhao-lu
ZL
The Institute of Radiation Medicine, Fudan University, Shanghai 200032, China.
Jin
Yi-zun
YZ
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D001388:Aziridines / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage; D005354:Fibrosarcoma / Q000378:metabolism / Q000473:pathology; D005434:Flow Cytometry; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D016685:Mitomycin / Q000737:chemistry / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
C526423:5-aziridinyl-3-hydroxyl-1-methylindole-4,7-dione; D000903:Antibiotics, Antineoplastic; D001388:Aziridines; D007211:Indoles; D009569:Nitric Oxide; D016685:Mitomycin; D052247:Nitric Oxide Synthase Type II