Timolati Francesco, Ott Daniel, Pentassuglia Laura, Giraud Marie-Noëlle, Perriard Jean-Claude, Suter Thomas M, Zuppinger Christian
Swiss Cardiovascular Center, University Hospital, CH-3010 Bern, Switzerland.
J Mol Cell Cardiol. 2006 Nov;41(5):845-54. doi: 10.1016/j.yjmcc.2006.08.002. Epub 2006 Sep 26.
Treatment of metastatic breast cancer with doxorubicin (Doxo) in combination with trastuzumab, an antibody targeting the ErbB2 receptor, results in an increased incidence of heart failure. Doxo therapy induces reactive oxygen species (ROS) and alterations of calcium homeostasis. Therefore, we hypothesized that neuregulin-1 beta (NRG), a ligand of the cardiac ErbB receptors, reduces Doxo-induced alterations of EC coupling by triggering antioxidant mechanisms. Adult rat ventricular cardiomyocytes (ARVM) were isolated and treated for 18-48 h. SERCA protein was analyzed by Western blot, EC coupling parameters by fura-2 and video edge detection, gene expression by RT-PCR, and ROS by DCF-fluorescence microscopy. At clinically relevant doses Doxo reduced cardiomyocytes contractility, SERCA protein and SR calcium content. NRG, similarly as the antioxidant N-acetylcystein (NAC), did not affect EC coupling alone, but protected against Doxo-induced damage. NRG and Doxo showed an opposite modulation of glutathione reductase gene expression. NRG, similarly as NAC, reduced peroxide- or Doxo-induced oxidative stress. Specific inhibitors showed, that the antioxidant action of NRG depended on signaling via the ErbB2 receptor and on the Akt- and not on the MAPK-pathway. Therefore, NRG attenuates Doxo-induced alterations of EC coupling and reduces oxidative stress in ARVM. Inhibition of the ErbB2/NRG signaling pathway by trastuzumab in patients concomitantly treated with Doxo might prevent beneficial effects of NRG in the myocardium.
用阿霉素（Doxo）联合曲妥珠单抗（一种靶向ErbB2受体的抗体）治疗转移性乳腺癌会导致心力衰竭发病率增加。阿霉素治疗会诱导活性氧（ROS）生成以及钙稳态改变。因此，我们推测神经调节蛋白-1β（NRG）作为心脏ErbB受体的配体，可通过触发抗氧化机制减少阿霉素诱导的兴奋-收缩偶联改变。分离成年大鼠心室心肌细胞（ARVM）并处理18 - 48小时。通过蛋白质印迹法分析肌浆网钙ATP酶（SERCA）蛋白，用fura - 2和视频边缘检测分析兴奋-收缩偶联参数，用逆转录聚合酶链反应（RT-PCR）分析基因表达，用二氯荧光素（DCF）荧光显微镜分析ROS。在临床相关剂量下，阿霉素降低心肌细胞收缩力、SERCA蛋白和肌浆网钙含量。NRG与抗氧化剂N-乙酰半胱氨酸（NAC）相似，单独不影响兴奋-收缩偶联，但能保护细胞免受阿霉素诱导的损伤。NRG和阿霉素对谷胱甘肽还原酶基因表达呈现相反的调节作用。NRG与NAC相似，可减少过氧化物或阿霉素诱导的氧化应激。特异性抑制剂表明，NRG的抗氧化作用依赖于通过ErbB2受体的信号传导以及Akt信号通路而非丝裂原活化蛋白激酶（MAPK）信号通路。因此，NRG可减轻阿霉素诱导的兴奋-收缩偶联改变并降低ARVM中的氧化应激。在接受阿霉素治疗的患者中，曲妥珠单抗抑制ErbB2/NRG信号通路可能会阻止NRG对心肌的有益作用。
