Activation of AMP-activated protein kinase inhibits the proliferation of human endothelial cells.
AMP-activated protein kinase (AMPK) is an evolutionary conserved energy-sensing enzyme that regulates cell metabolism. Emerging evidence indicates that AMPK also plays an important role in modulating endothelial cell function. In the present study, we investigated whether AMPK modulates endothelial cell growth. Treatment of cultured human umbilical vein endothelial cells with the AMPK activators 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), 6,7-dihydro-4-hydroxy-3-(2'-hydroxy[1,1'-biphenyl]-4-yl)-6-oxo-thieno[2,3-b]pyridine-5-carbonitrile (A-769662), or metformin inhibited cell proliferation and DNA synthesis. The antiproliferative action of AICAR was largely prevented by the adenosine kinase inhibitor 5'-iodotubercidin and mimicked by infecting endothelial cells with an adenovirus expressing constitutively active AMPK. In contrast, pharmacological blockade of endothelial nitric oxide synthase or heme oxygenase-1 activity failed to reverse the inhibition of endothelial cell growth by AICAR. Flow cytometry experiments revealed that pharmacological activation of AMPK arrested endothelial cells in the G₀/G₁ phase of the cell cycle, and this was associated with increases in p53 phosphorylation and p53, p21, and p27 protein expression and decreases in cyclin A protein expression and retinoblastoma protein phosphorylation. In addition, silencing p21 and p27 expression partially restored the mitogenic response of AMPK-activated cells. Finally, activation of AMPK by AICAR blocked the migration of endothelial cells after scrape injury and stimulated tube formation by endothelial cells plated onto Matrigel-coated plates. In conclusion, these studies demonstrate that AMPK activation inhibits endothelial cell proliferation by elevating p21 and p27 expression. In addition, they show that AMPK regulates endothelial cell migration and differentiation and identify AMPK as an attractive therapeutic target in treating diseases associated with aberrant endothelial cell growth.
Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA.
Kelly J
KJ
Peyton
Xiao-ming
XM
Liu
Yajie
Y
Yu
Benjamin
B
Yates
William
W
Durante
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D001713:Biphenyl Compounds; D018797:Cell Cycle Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019925:Cyclin A / Q000378:metabolism; D004789:Enzyme Activation; D016193:G1 Phase / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011753:Pyrones / Q000494:pharmacology; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D016160:Retinoblastoma Protein / Q000378:metabolism; D012265:Ribonucleotides / Q000494:pharmacology; D013876:Thiophenes / Q000494:pharmacology
D001713:Biphenyl Compounds; D018797:Cell Cycle Proteins; D019925:Cyclin A; D011753:Pyrones; D016160:Retinoblastoma Protein; D012265:Ribonucleotides; D013876:Thiophenes; D000620:Aminoimidazole Carboxamide; D052250:Nitric Oxide Synthase Type III; D051547:Heme Oxygenase-1; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide; C512408:4-hydroxy-3-(4-(2-hydroxyphenyl)phenyl)-6-oxo-7H-thieno(2,3-b)pyridine-5-carbonitrile