title: Extracellular heat shock proteins protect U937 cells from H2O2-induced apoptotic cell death.
abstract: The cytoprotective role of heat shock proteins (HSPs) has been demonstrated in various cell types however, only few studies have investigated the role of extracellular exposure to HSPs in the survival of human lymphoma cell line U937. In the present study, we investigated the effect of extracellular exposure to four HSPs (HSP90, HSP70, HSP60, and HSP47) on apoptotic cell death induced by either oxidative stress (hydrogen peroxide) or endoplasmic reticulum stress-mediated intracellular calcium overload. It was found that extracellular exposure to HSPs reduced the cytotoxicity induced by hydrogen peroxide, but not that evoked by thapsigargin (a specific inhibitor of cytosolic calcium reuptake which is able to induce endoplasmic reticulum stress with subsequent intracellular calcium overload). Similarly, it was observed that exogenous HSPs were able to suppress the caspase-3 activation induced by hydrogen peroxide. These findings indicate that extracellular HSPs increase the resistance of human lymphoma cell line U937 to apoptotic cell death induced by hydrogen peroxide and diminish oxidative stress-mediated injures.
authors.affiliation: Department of Physiology, Neuroimmunophysiology and Chrononutrition Research Group, Faculty of Science, University of Extremadura, Avda. de Elvas s/n, 06006, Badajoz, Spain.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Franco
authors.affiliation: Department of Physiology, Neuroimmunophysiology and Chrononutrition Research Group, Faculty of Science, University of Extremadura, Avda. de Elvas s/n, 06006, Badajoz, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Terrinca
authors.affiliation: Department of Physiology, Neuroimmunophysiology and Chrononutrition Research Group, Faculty of Science, University of Extremadura, Avda. de Elvas s/n, 06006, Badajoz, Spain.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Rodríguez
authors.affiliation: Department of Physiology, Neuroimmunophysiology and Chrononutrition Research Group, Faculty of Science, University of Extremadura, Avda. de Elvas s/n, 06006, Badajoz, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Espino
authors.affiliation: Department of Physiology, Neuroimmunophysiology and Chrononutrition Research Group, Faculty of Science, University of Extremadura, Avda. de Elvas s/n, 06006, Badajoz, Spain. pariente@unex.es.
authors.forename: José A
authors.initials: JA
authors.lastname: Pariente
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D006360:Heat-Shock Proteins / Q000502:physiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D019284:Thapsigargin / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D006360:Heat-Shock Proteins; D019284:Thapsigargin; D006861:Hydrogen Peroxide
keywords: Caspase; Cell viability; H2O2; Heat shock proteins; U937 cells