Fan Yuhua, Wang Chen, Zhang Yong, Hang Pengzhou, Liu Yan, Pan Zhenwei, Wang Ning, Du Zhimin
Institute of Clinical Pharmacy, the Second Affiliated Hospital, Harbin Medical University, Harbin, China.
Cell Physiol Biochem. 2013;31(1):80-91. doi: 10.1159/000343351. Epub 2013 Jan 22.
BACKGROUND/AIMS: Arsenic trioxide (As2O3) is a highly effective agent for treatment of acute promyelocytic leukemia (APL). However, consecutively administered As2O3 induces serious adverse cardiac effects, including long QT syndrome (LQTs) and even sudden cardiac death. Previous studies have shown that genistein (Gen) exerts anti-oxidant, anti-inflammatory, and anti-apoptotic effects. The present study aimed to explore the potential protective effects of Gen on As2O3-induced adverse cardiac effects, and to elucidate the underlying molecular mechanisms.
A rat model of As2O3-induced QT prolongation was generated by intravenous injection with As2O3. Surface electrocardiogram (ECG) and hemodynamics were employed to assess the LQTs and cardiac function. Intracellular calcium concentration ([Ca(2+)]i) and mitochondrial membrane potential (Δψm) were measured by confocal microscopy, and cardiomyocytes apoptosis were assessed by TUNEL assay. Western blot was applied to determine protein levels.
We found for the first time that treatment with Gen significantly reversed LQTs and dose-dependently improved As2O3-induced impairment of cardiac function. As2O3 elevated [Ca(2+)]i and Gen mitigated this effect. Meanwhile, Gen significantly reversed As2O3-mediated cardiomyocytes apoptosis. Furthermore, Gen dose-dependently inhibited the phosphorylated JNK and p38-MAPK (pp38-MAPK), and blocked Δψm collapse, and further decreased cleaved caspase-3.
Gen protects against the adverse cardiac effects of As2O3 partly by mitigating cardiomyocytes apoptosis induced by As2O3 through attenuating intracellular calcium overload and downregulating protein expression of p-JNK and pp38-MAPK to ameliorate the damage of Δψm leading to suppression of caspase-3 activation. Gen might be used as an adjunction therapy in APL patients receiving As2O3 treatment to avoid, at least to minimize, the adverse cardiac effects of As2O3.
背景/目的：三氧化二砷（As2O3）是治疗急性早幼粒细胞白血病（APL）的一种高效药物。然而，连续使用As2O3会引发严重的心脏不良反应，包括长QT综合征（LQTs）甚至心源性猝死。既往研究表明，染料木黄酮（Gen）具有抗氧化、抗炎和抗凋亡作用。本研究旨在探讨Gen对As2O3诱导的心脏不良反应的潜在保护作用，并阐明其潜在的分子机制。
通过静脉注射As2O3建立As2O3诱导的QT延长大鼠模型。采用体表心电图（ECG）和血流动力学评估LQTs和心脏功能。通过共聚焦显微镜测量细胞内钙浓度（[Ca(2+)]i）和线粒体膜电位（Δψm），并通过TUNEL法评估心肌细胞凋亡。应用蛋白质印迹法测定蛋白水平。
我们首次发现，Gen治疗可显著逆转LQTs，并呈剂量依赖性改善As2O3诱导的心脏功能损害。As2O3升高[Ca(2+)]i，而Gen可减轻这种作用。同时，Gen显著逆转As2O3介导的心肌细胞凋亡。此外，Gen呈剂量依赖性抑制磷酸化JNK和p38丝裂原活化蛋白激酶（pp38-MAPK），并阻止Δψm崩溃，进而降低裂解的半胱天冬酶-3水平。
Gen对As2O3所致心脏不良反应具有保护作用，其部分机制是通过减轻As2O3诱导的细胞内钙超载，下调p-JNK和pp38-MAPK蛋白表达，改善Δψm损伤，从而抑制半胱天冬酶-3活化，减轻心肌细胞凋亡。Gen可作为接受As2O3治疗的APL患者的辅助治疗药物，以避免或至少最小化As2O3的心脏不良反应。
