title: Increased heat shock protein 70 expression following toxicant-mediated cytotoxicity: a ubiquitous marker of toxicant exposure?
abstract: The up-regulation of heat shock protein (HSP) expression has been proposed as a general biomarker of cellular protection against various environmental stresses and chemicals. The present study investigated the possibility of using HSP70 up-regulation as a biomarker of toxicant exposure in vitro. Cells of a rat hepatoma cell line (FGC4) were exposed to concentrations of 1,3-dichloroacetone, duroquinone, diquat dibromide, menadione, hydrogen peroxide, cadmium chloride (CdCl2) and sodium (meta)arsenite (NaAsO2) that elicited 20-50% cytotoxicity over a 24-hour period, and HSP70 levels were measured by ELISA. Up-regulation of HSP70 expression was demonstrated following treatment with menadione, CdCl2 and NaAsO2, but not with the other chemicals tested. A shorter exposure time (6 hours) and/or the use of non-toxic concentrations reduced the level of HSP70 up-regulation with menadione, CdCl2 and NaAsO2, but did not uncover any up-regulation with the other chemicals. Although the toxicity of the majority of the chemicals tested is believed to involve an oxidative stress component, the results of this study clearly demonstrate that up-regulation of HSP70 expression cannot be used as a general biomarker of toxicant exposure in vitro.
authors.affiliation: School of Biomedical Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK.
authors.forename: Parivash
authors.initials: P
authors.lastname: Farzaneh
authors.forename: Abdolamir
authors.initials: A
authors.lastname: Allameh
authors.forename: Steven
authors.initials: S
authors.lastname: Pratt
authors.forename: Nicholas
authors.initials: N
authors.lastname: Moore
authors.forename: Lucy
authors.initials: L
authors.lastname: Travis
authors.forename: Elke
authors.initials: E
authors.lastname: Gottschalg
authors.forename: Clive
authors.initials: C
authors.lastname: Kind
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Fry
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism; D009499:Neutral Red / Q000378:metabolism; D051381:Rats; D015854:Up-Regulation / Q000187:drug effects*; D015262:Xenobiotics / Q000145:classification / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D018840:HSP70 Heat-Shock Proteins; D015262:Xenobiotics; D009499:Neutral Red