title: Thymoquinone-induced reactive oxygen species causes apoptosis of chondrocytes via PI3K/Akt and p38kinase pathway.
abstract: Thymoquinone (TQ), a bioactive ingredient of the volatile oil of black seed (Nigella sativa), has been shown to possess anti-neoplastic and anti-inflammatory effects on a variety of tumours. However, the precise mechanism of action is not clear in normal cells such as primary chondrocytes. So, we have investigated the effects of TQ on the apoptosis of chondrocytes with a focus on reactive oxygen species (ROS) production. In in vitro experiments, chondrocytes were cultured with increasing concentrations of TQ for 24 h or with 20 µmol/L TQ for the indicated time periods, and various experiments were performed to detect the apoptotic effects caused by TQ. The results showed that TQ significantly increases apoptosis. Apoptosis was dose- and time-dependently expressed, and the generation of ROS also dramatically increased in a dose-dependent manner. Pretreatment of N-acetyl-L-cysteine (NAC), an inhibitor of ROS, inhibited both TQ-induced apoptosis and ROS generation. Also, TQ up-regulated phosphorylation of phosphatidylinositol 3-kinase/Akt (PI3K/Akt) and mitogen-activated protein kinases ([MAPKs] p38kinase, ERK-1/-2, and JNKinase), and these effects were prevented by pretreatment of NAC. However, pretreatment with inhibitors of PI3K/Akt and MAPKs did not inhibit TQ-caused ROS generation. Among the inhibitors of PI3K/Akt, p38kinase, ERK-1/-2, and JNKinase, pretreatment with LY294002 and SB203580 abolished TQ-induced apoptosis, but PD98059 and SP600125 did not have any effect on TQ-caused apoptosis. These findings suggest that TQ-induced ROS generation regulates apoptosis by modulating PI3K/Akt and p38kinase pathways.
authors.affiliation: Department of Biological Science, College of Natural Sciences, Kongju National University, Gongju, Chungnam 182, Republic of Korea.
authors.forename: Seon-Mi
authors.initials: SM
authors.lastname: Yu
authors.forename: Song-Ja
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000838:Anions; D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D016227:Benzoquinones / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019902:Chondrocytes / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects; D016166:Free Radical Scavengers / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D000111:Acetylcysteine; D000838:Anions; D000873:Anthracenes; D016227:Benzoquinones; D016166:Free Radical Scavengers; D007093:Imidazoles; D007473:Ion Channels; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D011725:Pyridines; D017382:Reactive Oxygen Species; D048051:p38 Mitogen-Activated Protein Kinases; C432165:pyrazolanthrone; C003466:thymoquinone; C093642:SB 203580
keywords: Chondrocytes; Reactive oxygen species (ROS); Thymoquinone (TQ)