title: Doxorubicin-induced cardiotoxicity: direct correlation of cardiac fibroblast and H9c2 cell survival and aconitase activity with heat shock protein 27.
abstract: The use of doxorubicin (Dox) and its derivatives as chemotherapeutic drugs to treat patients with cancer causes dilated cardiomyopathy and congestive heart failure due to Dox-induced cardiotoxicity. In this work, using heat shock factor-1 wild-type (HSF-1(+/+)) and HSF-1 knockout (HSF-1(-/-)) mouse fibroblasts and embryonic rat heart-derived cardiac H9c2 cells, we show that the magnitude of protection from Dox-induced toxicity directly correlates with the level of the heat shock protein 27 (HSP27). Western blot analysis of normal and heat-shocked cells showed the maximum expression of HSP27 in heat-shocked cardiac H9c2 cells and no HSP27 in HSF-1(-/-) cells (normal or heat-shocked). Correspondingly, the cell viability, measured [with (3,4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay] after treatment with various concentrations of Dox, was the highest in heat-shocked H9c2 cells and the lowest in HSF-1(-/-) cells. Depleting HSP27 in cardiac H9c2 cells by small interfering (si)RNA also reduced the viability against Dox, confirming that HSP27 does protect cardiac cells against the Dox-induced toxicity. The cells that have lower HSP27 levels such as HSF-1(-/-), were found to be more susceptible for aconitase inactivation. Based on these results we propose a novel mechanism that HSP27 plays an important role in protecting aconitase from Dox-generated O(2)*(-), by increasing SOD activity. Such a protection of aconitase by HSP27 eliminates the catalytic recycling of aconitase released Fe(II) and its deleterious effects in cardiac cells.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA.
authors.forename: Samir
authors.initials: S
authors.lastname: Turakhia
authors.forename: C D
authors.initials: CD
authors.lastname: Venkatakrishnan
authors.forename: Kathy
authors.initials: K
authors.lastname: Dunsmore
authors.forename: Hector
authors.initials: H
authors.lastname: Wong
authors.forename: Periannan
authors.initials: P
authors.lastname: Kuppusamy
authors.forename: Jay L
authors.initials: JL
authors.lastname: Zweier
authors.forename: Govindasamy
authors.initials: G
authors.lastname: Ilangovan
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000008:administration & dosage*; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D032386:Myoblasts, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D051381:Rats; D013223:Statistics as Topic; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D000903:Antibiotics, Antineoplastic; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486114:Hspb1 protein, rat; D009363:Neoplasm Proteins; D004317:Doxorubicin; D013482:Superoxide Dismutase