Deciphering the Role of AMPK in Doxorubicin Cardiotoxicity

项目总结/摘要 阿霉素（DOX）是一种非常有效和广谱的抗癌药物，但可导致心力衰竭， 这给数百万接受过DOX治疗的癌症幸存者带来了严重的问题。因此，在本发明中， 鉴定可以降低DOX心脏毒性而不损害其抗肿瘤功效的药剂将是 临床应用价值大。腺苷酸活化蛋白激酶（AMPK）是一种重要的线粒体膜蛋白， 已被建议减少DOX在大多数基于细胞的细胞中的毒性作用， 问题研究抗糖尿病药物MET已被提议作为可减弱DOX的药剂 心脏毒性通过激活AMPK。然而，AMPK本身是否以及如何影响DOX在很大程度上是未知的。 体内心脏毒性。我们的初步研究证实了MET激活AMPK和阻断AMPK的能力。 DOX在体外和体内的心脏毒性作用。令人惊讶的是，在AMPKα2中DOX心脏毒性显著降低， 敲除（KO）小鼠和MK-8722（一种有效的泛AMPK激活剂）加剧，表明一些AMPK 同种型可能导致DOX心脏毒性，这与普遍认为AMPK通常 在DOX治疗的情况下具有心脏保护作用。这提出了一种可能性，即心脏保护作用的 MET可能通过与AMPK无关或与亚型特异性AMPK相关的机制介导 全酶该提案将检验AMPK的不同亚型对DOX的影响不同的假设。 通过不同的细胞和分子机制调节能量代谢， 线粒体质量控制过程。我们将确定异构体特异性的潜在差异作用， AMPK全酶在DOX心脏毒性中的作用，并确定八种AMPK中每一种的作用 使用药理学抑制剂和激活剂以及siRNA在心肌细胞中表达全酶， 介导的敲除。我们还将研究调节AMPK活性是否会影响DOX的心脏毒性 通过影响线粒体分裂或线粒体自噬。考虑到每一个国家的重要性日益增加， 由于AMPK功能中的同种型，已经进行了巨大的努力来开发可以调节AMPK的试剂 以异构体特异性方式的活性。预计拟议的研究将产生新的知识， 揭示了每种AMPK亚型在DOX心脏毒性中的功能作用，提示了新的亚型- 选择性治疗该项目将对治疗许多类型的癌症产生积极影响， 对DOX敏感

PROJECT SUMMARY/ABSTRACT Doxorubicin (DOX) is an extremely effective and wide-spectrum anticancer drug, but can lead to heart failure, which presents a serious problem to millions of cancer survivors who have been treated with DOX. Thus, identifying agents that can reduce DOX cardiotoxicity without compromising its antitumor efficacy would be of great clinical value. AMP-activated protein kinase (AMPK) is an essential regulator of mitochondrial homeostasis and energy metabolism that has been suggested to reduce DOX toxic effects in most cell-based studies. The anti-diabetic drug Metformin (MET) has been proposed as an agent which can attenuate DOX cardiotoxicity by activating AMPK. However, it is largely unknown whether and how AMPK per se affects DOX cardiotoxicity in vivo. Our preliminary studies confirmed the ability of MET to activate AMPK and to block the cardiotoxic effects of DOX in vitro and in vivo. Surprisingly, DOX cardiotoxicity is markedly reduced in AMPKα2 knockout (KO) mice and exacerbated by MK-8722, a potent pan-AMPK activator, suggesting that some AMPK isoforms may contribute to DOX cardiotoxicity, in stark contrast to the prevailing belief that AMPK is generally cardioprotective in the context of DOX treatment. This raises the possibility that the cardioprotective effects of MET may be mediated through mechanisms either unrelated to AMPK or related to an isoform-specific AMPK holoenzyme. This proposal will test the hypothesis that different isoforms of AMPK differentially impact DOX cardiotoxicity through distinct cellular and molecular mechanisms that regulate energy metabolism and mitochondrial quality control processes. We will ascertain the potentially differential roles of isoform-specific AMPK holoenzymes in DOX cardiotoxicity and identify the contributions of each of the eight AMPK holoenzymes expressed in cardiomyocytes using pharmacological inhibitors and activators as well as siRNA- mediated knockdown. We will also investigate whether modulating AMPK activity affects DOX cardiotoxicity through its effects on mitochondrial fission or mitophagy. Given the emerging importance of each of the isoforms in AMPK function, tremendous effort has been made to develop agents that can modulate AMPK activity in an isoform-specific manner. The proposed study is expected to generate new knowledge that will shed light on the functional role of each of the AMPK isoforms in DOX cardiotoxicity, suggesting novel isoform- selective therapeutics. This project will have a positive impact on the treatment of many types of cancer that are sensitive to DOX.