Antifungal drug itraconazole targets VDAC1 to modulate the AMPK/mTOR signaling axis in endothelial cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 112; no. 52; pp. E7276 - E7285
• Main Authors: 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.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 29-12-2015; National Acad Sciences
• Series: PNAS Plus
• Subjects: Adenosine triphosphatase; AMP-Activated Protein Kinases - metabolism; Angiogenesis; Animals; Antifungal Agents - pharmacology; Biological Sciences; Cell Line, Tumor; Cell Proliferation - drug effects; Cell Proliferation - genetics; Cells; Cells, Cultured; Enzyme Activation - drug effects; Fluorescence Resonance Energy Transfer; HEK293 Cells; HeLa Cells; Human Umbilical Vein Endothelial Cells - drug effects; Human Umbilical Vein Endothelial Cells - metabolism; Humans; Itraconazole - pharmacology; Metabolism; Metabolites; Microscopy, Fluorescence; Mitochondrial Swelling - drug effects; Phosphorylation - drug effects; PNAS Plus; Rats, Sprague-Dawley; RNA Interference; Signal Transduction - drug effects; TOR Serine-Threonine Kinases - metabolism; Voltage-Dependent Anion Channel 1 - antagonists & inhibitors; Voltage-Dependent Anion Channel 1 - genetics; Voltage-Dependent Anion Channel 1 - metabolism; VDAC1; itraconazole; metabolism; angiogenesis; mitochondria
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1512867112

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 ofmTOR signaling in endothelial cells and a promising target for the development of angiogenesis inhibitors.