Navarro Rosaura, Busnadiego Idoia, Ruiz-Larrea M Begoña, Ruiz-Sanz José Ignacio
Department of Physiology, Medicine and Dentistry School, University of the Basque Country, 48080-Bilbao, Spain.
Ann N Y Acad Sci. 2006 Dec;1090:419-28. doi: 10.1196/annals.1378.045.
Doxorubicin (DOX), an antineoplastic agent widely used for the treatment of cancer, belongs to the anthracycline family of antitumor antibiotics. DOX may undergo one-electron reduction to the corresponding semiquinone free radical by flavin-containing reductases. Under aerobic conditions, the semiquinone radical reacts rapidly with oxygen to generate superoxide anion, undergoing redox cycling. At moderate concentrations, reactive oxygen species (ROS) play an important role as regulatory mediators in signaling processes. We have shown that DOX increased phosphorylation of enzymes comprising mitogen-activated protein (MAP) kinase cascades in primary hepatocyte cultures, and that this action was independent of oxidant damage. In particular, extracellular signal-regulated kinase (ERK) was phosphorylated by the drug treatment. In this work, we have determined the possible involvement of particular free radicals in DOX-induced ERK phosphorylation in hepatocyte cultures by using specific free radical scavengers. The levels of ERK phosphorylation were measured by Western blot analysis with an anti-Thr202/Tyr204-phosphorylated p44/p42 MAPK antibody. Deferoxamine (DFO; iron chelator), catalase (hydrogen peroxide-removing enzyme), or alpha-tocopherol (peroxyl-radical scavenger) did not affect DOX-increased ERK phosphorylation levels. However, the cell-permeable superoxide dismutase mimetic MnTBAP and the flavin-containing enzyme inhibitor diphenyleneiodonium reverted DOX-induced effects. These results suggest that superoxide anions, probably generated by DOX metabolism, are involved in the effects of the anthracycline on the MAP kinase cascade activation.
阿霉素（DOX）是一种广泛用于治疗癌症的抗肿瘤药物，属于蒽环类抗肿瘤抗生素家族。DOX可通过含黄素的还原酶进行单电子还原生成相应的半醌自由基。在有氧条件下，半醌自由基与氧气迅速反应生成超氧阴离子，进行氧化还原循环。在中等浓度下，活性氧（ROS）作为信号传导过程中的调节介质发挥重要作用。我们已经表明，DOX可增加原代肝细胞培养物中包括丝裂原活化蛋白（MAP）激酶级联在内的酶的磷酸化，并且这种作用与氧化损伤无关。特别是，细胞外信号调节激酶（ERK）通过药物处理被磷酸化。在这项工作中，我们通过使用特定的自由基清除剂确定了特定自由基可能参与DOX诱导的肝细胞培养物中ERK磷酸化。通过用抗Thr202/Tyr204磷酸化的p44/p42 MAPK抗体进行蛋白质印迹分析来测量ERK磷酸化水平。去铁胺（DFO；铁螯合剂）、过氧化氢酶（过氧化氢去除酶）或α-生育酚（过氧自由基清除剂）不影响DOX增加的ERK磷酸化水平。然而，细胞可渗透的超氧化物歧化酶模拟物MnTBAP和含黄素的酶抑制剂二亚苯基碘鎓可逆转DOX诱导的效应。这些结果表明，可能由DOX代谢产生的超氧阴离子参与了蒽环类药物对MAP激酶级联激活的作用。
