calpain and Cardiotoxicity

Topics: Animals; Binding Sites; Biomarkers; Calpain; Cardiotoxicity; Connectin; Dependovirus; Dysferlin; Enzyme Stability; Gene Expression Regulation; Genetic Therapy; Mice, Knockout; MicroRNAs; Muscle Proteins; Muscle, Skeletal; Muscular Dystrophies, Limb-Girdle; Myocardium; Primates; Protein Domains; Proteolysis; RNA Splicing; Species Specificity; Tissue Distribution; Transgenes

We recently reported that doxorubicin decreased the expression of calpain-1/2, while inhibition of calpain activity promoted doxorubicin-induced cardiac injury in mice. In this study, we investigated whether and how elevation of calpain-2 could affect doxorubicin-triggered cardiac injury. Transgenic mice with inducible cardiomyocyte-specific expression of calpain-2 were generated. An acute cardiotoxicity was induced in both transgenic mice and their relevant wild-type littermates by injection of a single dose of doxorubicin (20 mg/kg) and cardiac injury was analyzed 5 days after doxorubicin injection. Cardiomyocyte-specific up-regulation of calpain-2 did not induce any adverse cardiac phenotypes under physiological conditions by age 3 months, but significantly reduced myocardial injury and improved myocardial function in doxorubicin-treated mice. Cardiac protection of calpain-2 up-regulation was also observed in a mouse model of chronic doxorubicin cardiotoxicity. Up-regulation of calpain-2 increased the protein levels of mitogen activated protein kinase phosphatase-1 (MKP-1) in cultured mouse cardiomyocytes and heart tissues. Over-expression of MKP-1 prevented, whereas knockdown of MKP-1 augmented doxorubicin-induced apoptosis in cultured cardiomyocytes. Moreover, knockdown of MKP-1 offset calpain-2-elicited protective effects against doxorubicin-induced injury in cultured cardiomyocytes. Mechanistically, up-regulation of calpain-2 reduced the protein levels of phosphatase and tensin homolog and consequently promoted Akt activation, leading to increased MKP-1 protein steady-state levels by inhibiting its degradation. Collectively, this study reveals a new role of calpain-2 in promoting MKP-1 expression via phosphatase and tensin homolog/Akt signaling. This study also suggests that calpain-2/MKP-1 signaling may represent new therapeutic targets for doxorubicin-induced cardiac injury.

Topics: Animals; Apoptosis; Calpain; Cardiotoxicity; Cells, Cultured; Doxorubicin; Dual Specificity Phosphatase 1; Gene Expression; Heart; Mice, Transgenic; Myocardium; Myocytes, Cardiac; Up-Regulation

Cardiotoxicity is a well-recognized side effect induced by chemotherapeutic drugs such as anthracycline and trastuzumab through different mechanisms. Currently, accumulating evidence supports that dexrazoxane (DZR) can minimize the risk of cardiotoxicity. In this study, we investigated whether dexrzoxane could reduce cardiotoxicity in the treatment of anthracycline combined with trastuzumab. We randomly divided 90 experimental F344 rats into control group, chemotherapeutics and trastuzumab (doxorubicin [DOX] + herceptin [Her]) group, and chemotherapeutics, trastuzumab, and DZR (DOX + Her + DZR) group. Animal status and body weight, cardiac function, serum cardiac markers, cardiomyocyte apoptosis of the rats, and expression level of calpain-2 were evaluated. Left ventricular ejection fraction (LVEF) and fractional shortening (FS) of the left ventricle were observed. The serum levels of malondialdehyde (MDA) and cardiac troponin I (cTnI) and cardiomyocyte apoptosis were detected by enzyme linked immunosorbent assay and TdT-mediated dUTP nick end labeling assays. The mRNA and protein level of calpain-2 were measured by reverse transcriptase polymerase chain reaction and Western blot. We observed that the LVEF and FS of the left ventricle were significantly higher in the DOX + Her + DZR group than that in the DOX + Her group (P < 0.05). The serum levels of MDA and cTnI between DOX + Her group and DOX + Her + DZR group were significantly different. In addition, cardiomyocyte apoptosis in the DOX + Her + DZR group was significantly less severe than that in the DOX + Her group (P < 0.05). After DZR treatment, the calpain-2 mRNA and protein levels in the DOX + Her + DZR group were significantly higher than the DOX + Her group (P < 0.05). Our results suggest that DZR can effectively reduce the cardiotoxicity of combinatorial treatment of trastuzumab and anthracycline partly through upregulating calpain-2.

Topics: Animals; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Apoptosis; Calpain; Cardiotonic Agents; Cardiotoxicity; Dexrazoxane; Doxorubicin; Heart Ventricles; Malondialdehyde; Models, Animal; Myocytes, Cardiac; Random Allocation; Rats, Inbred F344; RNA, Messenger; Stroke Volume; Trastuzumab; Troponin I; Ultrasonography; Up-Regulation