Involvement of peroxynitrite in capsaicin-induced apoptosis of C6 glioma cells.
Capsaicin induces apoptosis in some types of cells, but its mechanism remains obscure. In this study, peroxynitrite, a powerful oxidant generated from the reaction of superoxide and nitric oxide (NO) in biological system, was demonstrated to be responsible for capsaicin-mediated apoptosis in C6 glioma cells. Capsaicin-induced apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, and also identified by Annexin V staining and comet assay. Capsazepine and ruthenium red, the vanilloid receptor 1 (VR1/TPRV1) antagonists, did not inhibit capsaicin-induced apoptosis. Exposure to capsaicin not only promoted the generation of superoxide and iNOS, but also markedly suppressed the expression of SODs. Nitrite and nitrate, the NO metabolites accumulated in the medium, and the nitrotyrosine was also increased in proteins of C6 glioma cells exposed to capsaicin. Pretreatment of cells with 4 microM ebselen (a peroxynitrite scavenger) showed effective inhibitory effect on the capsaicin-induced apoptosis. These results suggest that peroxynitrite can act as a potential mediator in the capsaicin-induced apoptosis in C6 glioma cells.
Qiao
Shanlou
S
Department of Biochemistry, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan. qiaosl@aichi-med-u.ac.jp
Li
Weihua
W
Tsubouchi
Ryoko
R
Haneda
Miyako
M
Murakami
Keiko
K
Yoshino
Masataka
M
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001393:Azoles / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D002211:Capsaicin / Q000633:toxicity*; D002452:Cell Count / Q000379:methods; D045744:Cell Line, Tumor; D020552:Comet Assay / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005910:Glioma; D020287:In Situ Nick-End Labeling / Q000379:methods; D054833:Isoindoles; D051379:Mice; D018696:Neuroprotective Agents / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D016566:Organoselenium Compounds / Q000494:pharmacology; D030421:Peroxynitrous Acid / Q000502:physiology*; D010617:Phenanthridines / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
D017304:Annexin A5; D001393:Azoles; D054833:Isoindoles; D018696:Neuroprotective Agents; D009573:Nitrites; D016566:Organoselenium Compounds; D010617:Phenanthridines; D030421:Peroxynitrous Acid; C058428:hydroethidine; C042986:ebselen; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D013482:Superoxide Dismutase; D002211:Capsaicin