title: Proteasome inhibitor MG132 reduces growth of As4.1 juxtaglomerular cells via caspase-independent apoptosis.
abstract: The proteasome inhibitor MG132 has been shown to induce apoptotic cell death through the formation of reactive oxygen species (ROS). Here, we investigated the molecular mechanisms of MG132 in As4.1 juxtaglomerular cell death in relation to apoptosis and levels of ROS and glutathione (GSH). MG132 inhibited the growth of As4.1 cells with an IC(50) of approximately 0.3-0.4 microM at 48 h and induced cell death, accompanied by the loss of mitochondrial membrane potential (MMP; Psi(m)), Bcl-2 decrease, activations of caspase-3 and caspase-8, and PARP cleavage. MG132 increased intracellular ROS levels and GSH-depleted cell numbers. However, caspase inhibitors, especially Z-VAD (pan-caspase inhibitor) intensified cell growth inhibition, cell death, MMP (Psi(m)) loss, and Bcl-2 decrease in MG132-treated As4.1 cells. Z-VAD also slightly intensified increases in ROS levels and GSH depletion in MG132-treated As4.1 cells. In conclusion, MG132 reduced the growth of As4.1 cells via caspase-independent apoptosis. The changes in ROS and GSH levels by MG132 and caspase inhibitors partially influenced the growth inhibition and death of As4.1 cells.
authors.affiliation: Department of Physiology, Medical School, Institute for Medical Sciences, Chonbuk National University, JeonJu 561-180, Republic of Korea.
authors.forename: Yong Hwan
authors.initials: YH
authors.lastname: Han
authors.forename: Woo Hyun
authors.initials: WH
authors.lastname: Park
mesh_terms: D000818:Animals; D017209:Apoptosis; D061945:Caspase Inhibitors; D016923:Cell Death; D002460:Cell Line; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007606:Juxtaglomerular Apparatus / Q000166:cytology / Q000378:metabolism*; D007976:Leupeptins / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial; D051379:Mice; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D061988:Proteasome Inhibitors; D017382:Reactive Oxygen Species; D046988:Proteasome Endopeptidase Complex; D005978:Glutathione; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde