Resistance of PC12 cells against nitric oxide (NO)-induced toxicity in long-term culture: implication of neuronal NO synthase expression.
We have previously reported that a nitric oxide (NO)-donor, (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (NOR3) induced cell death even at a low concentration in undifferentiated PC12 cells. In the present study, we found that PC12 cells which were cultured long-term for over 80 passages acquired resistance to the NOR3-induced cell toxicity. After 24 h exposure to 10-100 microM NOR3, a concentration-dependent cell death was observed in short-term cultured PC12 cells (8-30 passages), but not in long-term cultured cells (over 80 passages). In the cells cultured short-term, the cell death was accompanied by nuclear condensation and fragmentation. We further examined the alterations in total glutathione (GSH) levels, and activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase in the short- and long-term cultured PC12 cells. SOD activity decreased in the long-term cultured cells, while catalase activity did not change. The GSH content significantly increased in the cells cultured long-term. Furthermore, the long-term but not the short-term cultured cells, expressed neuronal NO synthase (nNOS), but neither endothelial nor inducible NOS. These findings suggest that the PC12 cells acquire resistance to the NO-induced toxicity, accompanied by an increase in the GSH level and the expression of nNOS after long-term culture.
Yuyama
K
K
Laboratory of Molecular Recognition, Graduate School of Integrated Science, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
Yamamoto
H
H
Nakamura
K
K
Kato
T
T
Sora
I
I
Yamamoto
T
T
D000818:Animals; D002374:Catalase / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance / Q000502:physiology; D005978:Glutathione / Q000378:metabolism; D009569:Nitric Oxide / Q000633:toxicity*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009574:Nitro Compounds / Q000633:toxicity; D016716:PC12 Cells; D051381:Rats; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
D009574:Nitro Compounds; D009569:Nitric Oxide; C061872:FK 409; D002374:Catalase; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D013482:Superoxide Dismutase; D005978:Glutathione