Redox-proteomic analysis of doxorubicin-induced altered thiol activity in cardiomyocytes

Doxorubicin is an anticancer drug used in a wide range of cancer therapies, yet some side effects have been reported. One of these is cardiotoxicity, including cardiomyopathy and ultimately congestive heart failure. This damage to the heart has been shown to result from doxorubicin-induced reactive oxygen species. However, the cellular targets of doxorubicin-induced oxidative damage on cardiomyocytes are largely unknown. For this, a cysteine-labeling-based two-dimensional difference gel electrophoresis (2D-DIGE) combined with MALDI-TOF/TOF mass spectrometry (MALDI-TOF/TOF MS) were employed to analyze the impact of doxorubicin treatment on the redox regulation in rat cardiomyocytes. This study demonstrated 25 unique protein features that had significantly changed in their thiol reactivity and revealed that doxorubicin-induced cardiotoxicity involves dysregulation of protein folding, translational regulation and cytoskeleton regulation. Our work shows that this combined proteomic strategy provides a rapid method to study the molecular mechanisms of doxorubicin-induced cytotoxicity in the heart. The identified targets may be useful for further evaluation as potential cardiotoxic biomarkers during damage to the heart induced by doxorubicin, as well as possible diagnostic or therapeutic applications.