title: Exacerbated vulnerability to oxidative stress in astrocytic C6 glioma cells with stable overexpression of the glutamine transporter slc38a1.
abstract: We have previously demonstrated the functional expression of glutamine (Gln) transporter (GlnT) believed to predominate in neurons for the neurotransmitter glutamate pool by rat neocortical astrocytes devoid of neuronal marker expression, with exacerbated vulnerability to oxidative stress after transient overexpression. To evaluate molecular mechanisms underlying the exacerbation, we established stable GlnT transfectants in rat astrocytic C6 glioma cells. In two different clones of stable transfectants with increased intracellular Gln levels, exposure to hydrogen peroxide (H(2)O(2)) and A23187, but not to tunicamycin or 2,4-dinitrophenol, led to significant exacerbation of the cytotoxicity compared to cells with empty vector (EV). Stable GlnT overexpression led to a significant increase in heme oxygenase-1 protein levels in a manner sensitive to H(2)O(2), whereas H(2)O(2) was significantly more effective in increasing NO(2) accumulation and reactive oxygen species (ROS) generation in stable GlnT transfectants than in EV cells. Moreover, exposure to A23187 led to a more effective increase in the generation of ROS in stable GlnT transfectants than in stable EV transfectants. These results suggest that GlnT may play a role in the mechanisms underlying the determination of cellular viability in astrocytes through modulation of intracellular ROS generation.
authors.affiliation: Division of Pharmaceutical Sciences, Kanazawa University Graduate School of Natural Science and Technology, Kanazawa, Ishikawa, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Ogura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takarada
authors.forename: Noritaka
authors.initials: N
authors.lastname: Nakamichi
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kawagoe
authors.forename: Aya
authors.initials: A
authors.lastname: Sako
authors.forename: Ryota
authors.initials: R
authors.lastname: Nakazato
authors.forename: Yukio
authors.initials: Y
authors.lastname: Yoneda
mesh_terms: D026924:Amino Acid Transport System A / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D005910:Glioma / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D026924:Amino Acid Transport System A; D017382:Reactive Oxygen Species; C486716:Slc38a1 protein, rat; D009569:Nitric Oxide; D006861:Hydrogen Peroxide