OXIDATIVE AND NON-OXIDATIVE MECHANISMS IN THE INACTIVATION OF CARDIAC MITOCHONDRIAL ELECTRON-TRANSPORT CHAIN COMPONENTS BY DOXORUBICIN
OXIDATIVE AND NON-OXIDATIVE MECHANISMS IN THE INACTIVATION OF CARDIAC MITOCHONDRIAL ELECTRON-TRANSPORT CHAIN COMPONENTS BY DOXORUBICIN
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DOI：
10.1042/bj2590181
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发表时间：
1989-04-01
影响因子：
4.1
通讯作者：
DAVIES, KJA
中科院分区：
文献类型：
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作者：
MARCILLAT, O;ZHANG, Y;DAVIES, KJA
阿霉素（阿霉素）是一种强效的抗肿瘤药物，但由于严重的心脏毒性而限制了其临床应用。线粒体损伤是这种心脏毒性的主要组成部分，已经提出了电子传递链失活的竞争性氧化和非氧化机制。使用牛心脏亚线粒体制剂（SMP），我们现在已经发现，氧化和非氧化机制发生在体外，仅取决于阿霉素的浓度。多柔比星通过呼吸链的复合物I（其产生多柔比星半醌自由基、O2-、H2 O2和·OH）的氧化还原循环导致Vmax降低70%。在SMP孵育15 min期间，NADH脱氢酶的活性降低，孵育2 h后，NADH氧化酶的活性降低80%。这种失活仅需要25-50 μ M-阿霉素，并且代表真正的氧化损伤，因为NADH（用于阿霉素氧化还原循环）和氧气都是强制性的参与者。损伤似乎位于NADH脱氢酶黄素（阿霉素还原位点）和铁硫中心N-1之间。琥珀酸脱氢酶，琥珀酸氧化酶和细胞色素c氧化酶的活性强烈抑制高浓度的阿霉素，但这种现象并不涉及阿霉素的氧化还原循环（无NADH或氧需求）。除了细胞色素c氧化酶在与甚至1.0 mM-阿霉素孵育后仅被抑制30%之外，这些活性降低50%需要0.5 mM的阿霉素浓度。我们的结果表明，低浓度的阿霉素（50 μ M或更少）可以催化对NADH氧化途径的位点特异性氧化损伤。相比之下，电子传递链的非氧化失活需要高10倍（或更多）的阿霉素浓度;可能通过与心磷脂结合和/或广义膜离液效应。开发体内阻断阿霉素毒性的药物显然需要对心脏中阿霉素摄取进行详细的临床研究。
The quinonoid anthracycline, doxorubicin (Adriamycin) is a potent anti-neoplastic agent whose clinical use is limited be severe cardiotoxicity. Mitochondrial damage is a major component of this cardiotoxicity, and rival oxidative and non-oxidative mechanisms for inactivation of the electron transport chain have been proposed. Using bovine heart submitochondrial preparations (SMP) we have now found that both oxidative and non-oxidative mechanisms occur in vitro, depending solely on the concentration of doxorubicin employed. Redox cycling of doxorubicin by Complex I of the respiratory chain (which generates doxorubicin semiquinone radicals, O2-, H2O2, and .cntdot.OH) caused a 70% decrease in the Vmax. for NADH dehydrogenase during 15 min incubation of SMP, and an 80% decrease in NADH oxidase activity after 2 h incubation. This inactivation required only 25-50 .mu.M-doxorubicin and represents true oxidative damage, since both NADH (for doxorubicin redox cycling) and oxygen were obligatory participants. The damage appears localized between the NADH dehydrogenase flavin (site of doxorubicin reduction) and iron-sulphur centre N-1. Succinate dehydrogenase, succinate oxidase, and cytochrome c oxidase activities were strongly inhibited by higher doxorubicin concentrations, but this phenomenon did not involve doxorubicin redox cycling (no NADH or oxygen requirement). Doxorubicin concentrations of 0.5 mM were required for 50% decreases in these activities, except for cytochrome c oxidase which was only 30% inhibited following incubation with even 1.0 mM-doxorubicin. Our results indicate that low concentrations of doxorubicin (50 .mu.M or less) can catalyse a site-specific oxidative damage to the NADH oxidation pathway. In contrast, ten-fold higher doxorubicin concentrations (or more) are required for non-oxidative inactivation of the electron transport chain; probably via binding to cardiolipin and/or generalized membrane chaotropic effects. The development of agents to block doxorubicin toxicity in vivo will clearly require detailed clinical studies of doxorubicin uptake in the heart.