Activation of AMPK by simvastatin inhibited breast tumor angiogenesis via impeding HIF‐1α‐induced pro‐angiogenic factor

• Published in: Cancer science Vol. 109; no. 5; pp. 1627 - 1637
• Main Authors: Wang, Ji‐Chang, Li, Xiong‐Xiong, Sun, Xin, Li, Guang‐Yue, Sun, Jing‐Lan, Ye, Yuan‐Peng, Cong, Long‐Long, Li, Wei‐Ming, Lu, Shao‐Ying, Feng, Jun, Liu, Pei‐Jun
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.05.2018; John Wiley and Sons Inc
• Subjects: AMP; AMP-Activated Protein Kinases - antagonists & inhibitors; AMP-Activated Protein Kinases - physiology; AMPK; Angiogenesis; Animals; Antibodies; anti‐angiogenesis; Breast cancer; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug dosages; Endothelial cells; Enzyme Activation - drug effects; Female; Fibroblast Growth Factor 2 - analysis; Fibroblast growth factors; HIF‐1α; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit - antagonists & inhibitors; Hypoxia-Inducible Factor 1, alpha Subunit - physiology; Kinases; Lectins; Medical research; Mice; Mice, Inbred BALB C; Neovascularization, Pathologic - prevention & control; Original; Phosphorylation; Proteins; Simvastatin; Simvastatin - pharmacology; Smooth muscle; statin; Statins; Statistical analysis; Transcription; Tumors; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - analysis; United States > US; simvastatin; AMPK; HIF-1α; statin; anti-angiogenesis
• ISSN: 1347-9032; 1349-7006; 1349-7006
• DOI: 10.1111/cas.13570

Substantial data from preclinical studies have revealed the biphasic effects of statins on cardiovascular angiogenesis. Although some have reported the anti‐angiogenic potential of statins in malignant tumors, the underlying mechanism remains poorly understood. The aim of this study is to elucidate the mechanism by which simvastatin, a member of the statin family, inhibits tumor angiogenesis. Simvastatin significantly suppressed tumor cell‐conditioned medium‐induced angiogenic promotion in vitro, and resulted in dose‐dependent anti‐angiogenesis in vivo. Further genetic silencing of hypoxia‐inducible factor‐1α (HIF‐1α) reduced vascular endothelial growth factor and fibroblast growth factor‐2 expressions in 4T1 cells and correspondingly ameliorated HUVEC proliferation facilitated by tumor cell‐conditioned medium. Additionally, simvastatin induced angiogenic inhibition through a mechanism of post‐transcriptional downregulation of HIF‐1α by increasing the phosphorylation level of AMP kinase. These results were further validated by the fact that 5‐aminoimidazole‐4‐carboxamide ribonucleotide reduced HIF‐1α protein levels and ameliorated the angiogenic ability of endothelial cells in vitro and in vivo. Critically, inhibition of AMPK phosphorylation by compound C almost completely abrogated simvastatin‐induced anti‐angiogenesis, which was accompanied by the reduction of protein levels of HIF‐1α and its downstream pro‐angiogenic factors. These findings reveal the mechanism by which simvastatin induces tumor anti‐angiogenesis, and therefore identifies the target that explains the beneficial effects of statins on malignant tumors. Simvastatin significantly suppressed tumor angiogenesis promoted by HIF‐1α‐induced pro‐angiogenic factors in 4T1 tumor cells. Further inhibition of AMPK phosphorylation by compound C almost completely abrogated simvastatin‐induced anti‐angiogenesis, which was accompanied by the reduction of protein levels of HIF‐1α and its downstream pro‐angiogenic factors.