Chloroquine-induced nitric oxide increase and cell death is dependent on cellular GSH depletion in A172 human glioblastoma cells.
Chloroquine (CQ) is used to treat malaria and a variety of inflammatory diseases including systemic lupus erythematosus and rheumatoid arthritis. However, CQ is known to cause cytotoxicity of which mechanism is still uncertain. This study investigated the molecular mechanism responsible for the cell death in CQ-treated A172 human glioblastoma cells. CQ-induced apoptotic cell death of the cells in a time- and concentration-dependent manner. CQ also increased the production of nitric oxide in the cells. However, the pretreatment with aminoguanidine (AG) and N-Omega-nitro-l-arginine methyl ester (NAME), nitric oxide synthase inhibitors, did not block the CQ-induced cell death. In contrast to NO level increase, the level of intracellular reactive oxygen species (ROS) and their extracellular release were transiently and mildly increased by CQ. In addition, CQ depleted cellular GSH content, which was accompanied with time-dependent increase in GSH peroxidase without any significant change in GSH reductase activity. Glutathione (GSH) S-transferase activity was only transiently increased at 15 min treatment with CQ. Furthermore, the CQ-induced cell death was significantly suppressed when intracellular GSH decrease was prevented by the pretreatment with N-acetylcysteine (NAC) or glutathione ethylester (GSH-EE). At the same time, the pretreatment of the cells with NAC and GSH-EE significantly blocked the CQ-induced NO increase, representing that CQ-induced NO increase was resulted from the depletion of GSH. CQ also induced time-dependent increase in Bax level and caspase-3 activity with no change in Bcl-2 level. Overall, these results suggest that CQ-induced NO increase and cell death are dependent on GSH depletion, the cellular redox changes.
Park
Byung Chul
BC
College of Pharmacy, Yeungnam University, Gyeongsan 712-749, South Korea.
Park
Seung Hee
SH
Paek
Seung-Hwan
SH
Park
Su-Young
SY
Kwak
Mi-Kyoung
MK
Choi
Han Gon
HG
Yong
Chul Soon
CS
Yoo
Bong Kyu
BK
Kim
Jung-Ae
JA
D000962:Antimalarials / Q000633:toxicity*; D018501:Antirheumatic Agents / Q000633:toxicity*; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002738:Chloroquine / Q000633:toxicity*; D005909:Glioblastoma; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D000962:Antimalarials; D018501:Antirheumatic Agents; C494826:BAX protein, human; D009573:Nitrites; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D009569:Nitric Oxide; D002738:Chloroquine; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D053148:Caspase 3; D005978:Glutathione