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.

Doxorubicin increases the susceptibility of brain mitochondria to Ca2+-induced permeability transition and oxidative damage

“…4), which reinforces the idea that animals subjected to DOX treatment present high levels of oxidative stress. Recently, it has been shown that heat shock protein 27 protects the aconitase activity of cardiac cells by increasing the activity of superoxide dismutase [55].…”

A toxicoproteomic study on cardioprotective effects of pre-administration of docetaxel in a mouse model of adriamycin-induced cardiotoxicity

“…Among t he differentially expressed proteins, aconitase (peak no. 11) was the most drastically reduced in this study and has been reported to be inactivated b y ADR treatment [33,34]. A lso, Ldha protein ( peak no.…”

Characterization of hsp27 kinases activated by elevated aortic pressure in heart

“…The expression and/or phosphorylation of hsp27 in the heart is increased in response to chronic pressure overload [20], both physiological and pathological hypertrophy [13], heart failure [21,38,39], oxidative stress [24,25], ischemic injury [22], and haemorrhagic shock [23]. Increased hsp27 expression prevents cardiac dysfunction and hypertrophy during chronic pressure overload [13], protects against doxorubicin-induced cardiomyopathy [26,27], and prevents tachypacing-induced atrial remodelling and atrial fibrillation [14,17,16,19]. The ability of heat shock to protect against doxorubicin-induced cardiomyopathy involves an increase in p38 activity and hsp27 phosphorylation [26,27].…”

“…Increased hsp27 expression prevents cardiac dysfunction and hypertrophy during chronic pressure overload [13], protects against doxorubicin-induced cardiomyopathy [26,27], and prevents tachypacing-induced atrial remodelling and atrial fibrillation [14,17,16,19]. The ability of heat shock to protect against doxorubicin-induced cardiomyopathy involves an increase in p38 activity and hsp27 phosphorylation [26,27]. Furthermore, the protective effects of hsp27 in tachypacing were prevented by a phosphodefective mutant of hsp27 [16].…”

“…Furthermore, hsp27 phosphorylation plays an important role in heat-shock-induced prevention of doxorubicin cardiotoxicity [26,27] and is associated with improved recovery of function following ischemic injury [28]. Kinases known to phosphorylate hsp27 include PKA, PKB, PKC, PKD, PKG, MK2, MK3, and MK5/PRAK (Fig.…”