title: Implication of reactive oxygen species, ERK1/2, and p38MAPK in sodium salicylate-induced heat shock protein 72 expression in C6 glioma cells.
abstract: Sodium salicylate, one of anti-inflammatory agents, is known to partially induce the heat shock response: it stimulates the DNA-binding of heat shock factor 1 (HSF1) without inducing heat shock gene expression. Here we show that when C6 glioma cells are recovered from sodium salicylate treatment, they highly induce heat shock protein 72 (HSP72), but not HSP73 and HSP90, demonstrating that salicylate-induced inert HSF1 can be fully activated into a transcriptionally competent form by sodium salicylate recovery (SR)-specific mechanism. Fluorescent analysis using 2',7'-dichlorodihydrofluorescein diacetate revealed that sodium salicylate enhanced reactive oxygen species (ROS) production. N-acetyl-L-cysteine (NAC, a ROS scavenger) completely suppressed SR-induced HSP72 synthesis and HSP72 promoter-driven CAT reporter gene transcription as well as salicylate-induced HSF1-DNA binding, indicating a critical role(s) of ROS in the SR-induced HSP72 gene regulation. We also show that treatment of C6 cells with sodium salicylate activated p38MAPK and inactivated ERK1/2 in a ROS-independent manner and activities of these protein kinases returned during recovery period to the control level. Inhibiting p38MAPK and ERK1/2 with the p38MAPK inhibitors (SB203580 and SB202190) and the MEK1/2 inhibitor (PD98059 and U0126) or with expression of dominant negative p38MAPK and ERK1/2 abolished SR-induced HSP72 synthesis and HSP70 promoter-driven CAT activity. However, sodium salicylate-induced HSF1-DNA binding was not affected by the p38MAPK inhibitor or the MEK1/2 inhibitor. These findings suggest that sodium salicylate partially activates HSF1 via ROS production and p38MAPK activation and the salicylate-induced inert HSF1 can be fully activated into a transcriptionally competent form by the ERK1/2 signaling pathways that are activated independently of ROS during SR.
authors.affiliation: Department of Molecular Biology, College of Natural Sciences, Pusan National University, Pusan 609-735, Korea.
authors.forename: Myoung Suk
authors.initials: MS
authors.lastname: Seo
authors.forename: Su Young
authors.initials: SY
authors.lastname: Oh
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Park
authors.forename: Sun Mi
authors.initials: SM
authors.lastname: Kim
authors.forename: Min Young
authors.initials: MY
authors.lastname: Kim
authors.forename: Song Iy
authors.initials: SI
authors.lastname: Han
authors.forename: Hye Gyeong
authors.initials: HG
authors.lastname: Park
authors.forename: Ho Sung
authors.initials: HS
authors.lastname: Kang
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005909:Glioblastoma; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012980:Sodium Salicylate / Q000494:pharmacology*; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004268:DNA-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; C000619709:Hsf1 protein, rat; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D004247:DNA; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D012980:Sodium Salicylate