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Loss of multidrug resistance-associated protein 1 potentiates chronic doxorubicin-induced cardiac dysfunction in mice.

ABSTRACT: Doxorubicin (DOX), an effective cancer chemotherapeutic agent, induces dose-dependent cardiotoxicity, in part due to its ability to cause oxidative stress. We investigated the role of multidrug resistance-associated protein 1 (Mrp1/Abcc1) in DOX-induced cardiotoxicity in C57BL wild-type (WT) mice and their Mrp1 null (Mrp1(-/-)) littermates. Male mice were administered intraperitoneal DOX (3 or 2 mg/kg body weight) or saline twice a week for 3 weeks and examined 2 weeks after the last dose (protocol A total dose: 18 mg/kg) or for 5 weeks, and mice were examined 48 hours and 2 weeks after the last dose (protocol B total dose: 20 mg/kg). Chronic DOX induced body weight loss and hemotoxicity, adverse effects significantly exacerbated in Mrp1(-/-) versus WT mice. In the heart, significantly higher basal levels of glutathione (1.41-fold ± 0.27-fold) and glutathione disulfide (1.35-fold ± 0.16-fold) were detected in Mrp1(-/-) versus WT mice, and there were comparable decreases in the glutathione/glutathione disulfide ratio in WT and Mrp1(-/-) mice after DOX administration. Surprisingly, DOX induced comparable increases in 4-hydroxynonenal glutathione conjugate concentration in hearts from WT and Mrp1(-/-) mice. However, more DOX-induced apoptosis was detected in Mrp1(-/-) versus WT hearts (P < 0.05) (protocol A), and cardiac function, assessed by measurement of fractional shortening and ejection fraction with echocardiography, was significantly decreased by DOX in Mrp1(-/-) versus WT mice (P < 0.05; 95% confidence intervals of 20.0%-24.3% versus 23.7%-29.5% for fractional shortening, and 41.5%-48.4% versus 47.7%-56.7% for ejection fraction; protocol B). Together, these data indicate that Mrp1 protects the mouse heart against chronic DOX-induced cardiotoxicity.

SUBMITTER: Zhang W

PROVIDER: S-EPMC4613956 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:The use of doxorubicin, a potent chemotherapeutic agent, is limited by cardiotoxicity. We tested the hypothesis that decreased soluble guanylate cyclase (sGC) enzyme activity contributes to the development of doxorubicin-induced cardiotoxicity.Doxorubicin administration (20?mg/kg, intraperitoneally [IP]) reduced cardiac sGC activity in wild-type (WT) mice. To investigate whether decreased sGC activity contributes to doxorubicin-induced cardiotoxicity, we studied mice with cardiomyocyte-specific deficiency of the sGC ?1-subunit (mice with cardiomyocyte-specific deletion of exon 6 of the sGC?1 allele [sGC?1-/-CM]). After 12 weeks of doxorubicin administration (2?mg/kg/week IP), left ventricular (LV) systolic dysfunction was greater in sGC?1-/-CM than WT mice. To further assess whether reduced sGC activity plays a pathogenic role in doxorubicin-induced cardiotoxicity, we studied a mouse model in which decreased cardiac sGC activity was induced by cardiomyocyte-specific expression of a dominant negative sGC?1 mutant (DNsGC?1) upon doxycycline removal (Tet-off). After 8 weeks of doxorubicin administration, DNsGC?1tg/+, but not WT, mice displayed LV systolic dysfunction and dilatation. The difference in cardiac function and remodeling between DNsGC?1tg/+ and WT mice was even more pronounced after 12 weeks of treatment. Further impairment of cardiac function was attenuated when DNsGC?1 gene expression was inhibited (beginning at 8 weeks of doxorubicin treatment) by administering doxycycline. Furthermore, doxorubicin-associated reactive oxygen species generation was higher in sGC?1-deficient than WT hearts. Innovation and Conclusion: These data demonstrate that a reduction in cardiac sGC activity worsens doxorubicin-induced cardiotoxicity in mice and identify sGC as a potential therapeutic target. Various pharmacological sGC agonists are in clinical development or use and may represent a promising approach to limit doxorubicin-associated cardiotoxicity. Antioxid. Redox Signal. 26, 153-164.

Project description:BACKGROUND:Empagliflozin showed efficacy in controlling glycaemia, leading to reductions in HbA1c levels, weight loss and blood pressure, compared to standard treatment. Moreover, the EMPA-REG OUTCOME trial demonstrated a 14% reduction of major adverse cardiovascular events (MACE), a 38% reduction in cardiovascular (CV) death and a 35% reduction in the hospitalization rate for heart failure (HF). These beneficial effect on HF were apparently independent from glucose control. However, no mechanistic in vivo studies are available to explain these results, yet. We aimed to determine the effect of empagliflozin on left ventricular (LV) function in a mouse model of doxorubicin-induced cardiomyopathy (DOX-HF). METHODS:Male C57Bl/6 mice were randomly assigned to the following groups: controls (CTRL, n?=?7), doxorubicin (DOX, n?=?14), DOX plus empagliflozin (DOX?+?EMPA, n?=?14), or DOX plus furosemide (DOX?+?FURO group, n?=?7). DOX was injected intraperitoneally. LV function was evaluated at baseline and after 6 weeks of treatment using high-resolution echocardiography with 2D speckle tracking (Vevo 2100). Histological assessment was obtained using Haematoxylin and Eosin and Masson's Goldner staining. RESULTS:A significant decrease in both systolic and diastolic LV function was observed after 6 weeks of treatment with doxorubicin. EF dropped by 32% (p?=?0.002), while the LS was reduced by 42% (p?<?0.001) and the CS by 50% (p?<?0.001). However, LV function was significantly better in the DOX?+?EMPA group, both in terms of EF (61.30?±?11% vs. 49.24?±?8%, p?=?0.007), LS (- 17.52?±?3% vs. - 13.93?±?5%, p?=?0.04) and CS (- 25.75?±?6% vs. - 15.91?±?6%, p?<?0.001). Those results were not duplicated in the DOX?+?FURO group. Hearts from the DOX?+?EMPA group showed a 50% lower degree of myocardial fibrosis, compared to DOX mice (p?=?0.03). No significant differences were found between the DOX?+?FURO and the DOX group (p?=?0.103). CONCLUSION:Empagliflozin attenuates the cardiotoxic effects exerted by doxorubicin on LV function and remodelling in nondiabetic mice, independently of glycaemic control. These findings support the design of clinical studies to assess their relevance in a clinical setting.

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Loss of multidrug resistance-associated protein 1 potentiates chronic doxorubicin-induced cardiac dysfunction in mice.

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