Doxorubicin-induced cardiotoxicity: direct correlation of cardiac fibroblast and H9c2 cell survival and aconitase activity with heat shock protein 27.
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.
Turakhia
Samir
S
Division of Cardiovascular Medicine, Department of Internal Medicine, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA.
Venkatakrishnan
C D
CD
Dunsmore
Kathy
K
Wong
Hector
H
Kuppusamy
Periannan
P
Zweier
Jay L
JL
Ilangovan
Govindasamy
G
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*
D000903:Antibiotics, Antineoplastic; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486114:Hspb1 protein, rat; D009363:Neoplasm Proteins; D004317:Doxorubicin; D013482:Superoxide Dismutase