Head Sarah A, Shi Wei, Zhao Liang, Gorshkov Kirill, Pasunooti Kalyan, Chen Yue, Deng Zhiyou, Li Ruo-jing, Shim Joong Sup, Tan Wenzhi, Hartung Thomas, Zhang Jin, Zhao Yingming, Colombini Marco, Liu Jun O
Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205;
Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205; Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701;
Proc Natl Acad Sci U S A. 2015 Dec 29;112(52):E7276-85. doi: 10.1073/pnas.1512867112. Epub 2015 Dec 10.
Itraconazole, a clinically used antifungal drug, was found to possess potent antiangiogenic and anticancer activity that is unique among the azole antifungals. Previous mechanistic studies have shown that itraconazole inhibits the mechanistic target of rapamycin (mTOR) signaling pathway, which is known to be a critical regulator of endothelial cell function and angiogenesis. However, the molecular target of itraconazole that mediates this activity has remained unknown. Here we identify the major target of itraconazole in endothelial cells as the mitochondrial protein voltage-dependent anion channel 1 (VDAC1), which regulates mitochondrial metabolism by controlling the passage of ions and small metabolites through the outer mitochondrial membrane. VDAC1 knockdown profoundly inhibits mTOR activity and cell proliferation in human umbilical vein cells (HUVEC), uncovering a previously unknown connection between VDAC1 and mTOR. Inhibition of VDAC1 by itraconazole disrupts mitochondrial metabolism, leading to an increase in the cellular AMP:ATP ratio and activation of the AMP-activated protein kinase (AMPK), an upstream regulator of mTOR. VDAC1-knockout cells are resistant to AMPK activation and mTOR inhibition by itraconazole, demonstrating that VDAC1 is the mediator of this activity. In addition, another known VDAC-targeting compound, erastin, also activates AMPK and inhibits mTOR and proliferation in HUVEC. VDAC1 thus represents a novel upstream regulator of mTOR signaling in endothelial cells and a promising target for the development of angiogenesis inhibitors.
伊曲康唑是一种临床使用的抗真菌药物，被发现具有强大的抗血管生成和抗癌活性，这在唑类抗真菌药物中是独一无二的。先前的机制研究表明，伊曲康唑抑制雷帕霉素的机制性靶点（mTOR）信号通路，该通路已知是内皮细胞功能和血管生成的关键调节因子。然而，介导这种活性的伊曲康唑分子靶点仍不清楚。在这里，我们确定内皮细胞中伊曲康唑的主要靶点是线粒体蛋白电压依赖性阴离子通道1（VDAC1），它通过控制离子和小代谢物穿过线粒体外膜来调节线粒体代谢。VDAC1基因敲低显著抑制人脐静脉细胞（HUVEC）中的mTOR活性和细胞增殖，揭示了VDAC1与mTOR之间以前未知的联系。伊曲康唑对VDAC1的抑制会破坏线粒体代谢，导致细胞内AMP:ATP比值增加，并激活AMP激活的蛋白激酶（AMPK），AMPK是mTOR的上游调节因子。VDAC1基因敲除细胞对伊曲康唑激活AMPK和抑制mTOR具有抗性，表明VDAC1是这种活性的介导者。此外，另一种已知的靶向VDAC的化合物埃拉斯汀也能激活AMPK，并抑制HUVEC中的mTOR和细胞增殖。因此，VDAC1代表内皮细胞中mTOR信号的一种新型上游调节因子，也是开发血管生成抑制剂的一个有前景的靶点。
