Interaction of caveolin-1, nitric oxide, and nitric oxide synthases in hypoxic human SK-N-MC neuroblastoma cells.
Neuroblastoma cells are capable of hypoxic adaptation, but the mechanisms involved are not fully understood. We hypothesized that caveolin-1 (cav-1), a plasma membrane signal molecule, might play a role in protecting neuroblastoma cells from oxidative injury by modulating nitric oxide (NO) production. We investigated the alterations of cav-1, cav-2, nitric oxide synthases (NOS), and NO levels in human SK-N-MC neuroblastoma cells exposed to hypoxia with 2% [O2]. The major discoveries include: (i) cav-1 but not cav-2 was up-regulated in the cells exposed to 15 h of hypoxia; (ii) NO donor 1-[N, N-di-(2-aminoethyl) amino] diazen-1-ium-1, 2-diolate up-regulated the expression of cav-1, whereas the non-selective NOS inhibitor N(G)-nitro-L-arginine methyl ester and inducible NOS (iNOS) inhibitor 1400W each abolished the increase in cav-1 expression in the hypoxic SK-N-MC cells. These results suggest that iNOS-induced NO production contributes to the up-regulation of cav-1 in the hypoxic SK-N-MC cells. Furthermore, we studied the roles played by cav-1 in regulating NO, NOS, and apoptotic cell death in the SK-N-MC cells subjected to 15 h of hypoxic treatment. Both cav-1 transfection and cav-1 scaffolding domain peptide abolished the induction of iNOS, reduced the production of NO, and reduced the rates of apoptotic cell death in the hypoxic SK-N-MC cells. These results suggest that increased expression of cav-1 in response to hypoxic stimulation could prevent oxidative injury induced by reactive oxygen species. The interactions of cav-1, NO, and NOS could be an important signal pathway in protecting the neuroblastoma cells from oxidative injury, contributing to the hypoxic tolerance of neuroblastoma cells.
Shen
Jiangang
J
School of Chinese Medicine, The University of Hong Kong, Hong Kong.
Lee
Waisin
W
Li
Yue
Y
Lau
Chi Fai
CF
Ng
Kwong Man
KM
Fung
Man Lung
ML
Liu
Ke Jian
KJ
D000704:Analysis of Variance; D017304:Annexin A5 / Q000378:metabolism; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D051243:Caveolin 2 / Q000235:genetics / Q000378:metabolism; D015687:Cell Hypoxia / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D003671:DEET / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009447:Neuroblastoma; D009569:Nitric Oxide / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014162:Transfection / Q000379:methods
D017304:Annexin A5; D051242:Caveolin 1; D051243:Caveolin 2; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D003671:DEET; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D019331:NG-Nitroarginine Methyl Ester