Doxorubicin causes transient activation of protein poly(ADP-ribosyl)ation in H9c2 cardiomyocytes

Chrysophanol protects against doxorubicin-induced cardiotoxicity by suppressing cellular PARylation

The clinical application of doxorubicin (DOX) in cancer chemotherapy is limited by its life-threatening cardiotoxic effects. Chrysophanol (CHR), an anthraquinone compound isolated from the rhizome of Rheum palmatum L., is considered to play a broad role in a variety of biological processes. However, the effects of CHR׳s cardioprotection in DOX-induced cardiomyopathy is poorly understood. In this study, we found that the cardiac apoptosis, mitochondrial injury and cellular PARylation levels were significantly increased in H9C2 cells treated by Dox, while these effects were suppressed by CHR. Similar results were observed when PARP1 activity was suppressed by its inhibitors 3-aminobenzamide (3AB) and ABT888. Ectopic expression of PARP1 effectively blocked this CHR׳s cardioprotection against DOX-induced cardiomyocyte injury in H9C2 cells. Furthermore, pre-administration with both CHR and 3AB relieved DOX-induced cardiac apoptosis, mitochondrial impairment and heart dysfunction in Sprague-Dawley rat model. These results revealed that CHR protects against DOX-induced cardiotoxicity by suppressing cellular PARylation and provided critical evidence that PARylation may be a novel target for DOX-induced cardiomyopathy.

sFRP1 has a biphasic effect on doxorubicin-induced cardiotoxicity in a cellular location-dependent manner in NRCMs and Rats

Doxorubicin (Dox) is an effective anticancer drug, however, its clinical application is restricted by the life-threatening cardiotoxic effects. Secreted Frizzled-related protein 1 (sFRP1) has been reported to participate in both the cancer and cardiovascular diseases and was one of the differential expression genes in normal hearts compared with Dox-treated hearts. Thus, it is important to reveal the potential role of sFRP1 in Dox-induced cardiotoxicity. Here, we show that sFRP1 has a biphasic effect on Dox-induced cardiotoxicity in a location-dependent manner. The secretion of sFRP1 was significantly increased in Dox-treated neonatal rat cardiomyocytes (NRCMs) (1 µM) and SD rats (5 mg/kg/injection at day 1, 5, and 9, i.p.). Adding the anti-sFRP1 antibody (0.5 µg/ml) and inhibiting sFRP1 secretion by caffeine (5 mM) both relieved Dox-induced cardiotoxicity through activating Wnt/β-catenin signaling, whereas increasing the secretion of sFRP1 by heparin (100 µg/ml) had the opposite effect. The intracellular level of sFRP1 was significantly decreased after Dox treatment both in vitro and in vivo. Knockdown of sFRP1 by sgRNA aggravated Dox-induced cardiotoxicity, while moderate overexpression of sFRP1 by Ad-sFRP1 exhibited protective effect. Besides, poly(ADP-ribosyl) polymerase-1 (PARP1) was screened as an interacting partner of sFRP1 in NRCMs by mass spectrometry. Our results suggested that the intracellular sFRP1 protected NRCMs from Dox-induced cardiotoxicity by interacting with PARP1. Thus, our results provide a novel evidence that sFRP1 has a biphasic effect on Dox-induced cardiotoxicity. In addition, the oversecretion of sFRP1 might be used as a biomarker to indicate the occurrence of cardiotoxicity induced by Dox treatment.