Enterostatin inhibition of angiogenesis: possible role of pAMPK and vascular endothelial growth factor A (VEGF-A).
BACKGROUND
We utilized a genomic analysis of the response of neuronal GT1-7 cells to enterostatin to identify pathways responsive to this peptide. This information, together with reported properties of the enterostatin receptor, suggested that enterostatin may have an effect on angiogenesis.


METHODS
To investigate this hypothesis, we studied the effect of enterostatin as an antiangiogenic agent in two angiogenic tissue culture model systems.


RESULTS
Enterostatin induced a 50% or greater inhibition in the angiogenic response of human fat cells and had a U-shaped bimodal dose-response effect in inhibiting angiogenesis in a human placental vein angiogenesis model. To further understand this response, we tested enterostatin's effect in a human hepatoma cell line (HepG2 cells) that was subjected to glucose deprivation, a condition known to induce angiogenesis in other tumor cell lines. Phosphorylated AMP kinase (pAMPK) levels and vascular endothelial growth factor A (VEGF-A) mRNA expression were elevated robustly after incubation of HepG2 cells in the absence of glucose for 4 h, but 15 min incubation with enterostatin dramatically inhibited this pAMPK activation and reduced VEGF-A gene expression after 1 h incubation with enterostatin. The AMPK activator 5-aminoimidazole-4-carboximide ribonucleoside (AICAR) induced VEGF-A expression.


CONCLUSIONS
These data suggest that enterostatin has an antiangiogenic effect and suggest that it regulates VEGF-A gene expression through inhibition of AMPK activity.
Park
M
M
Center for Advanced Nutrition, Utah State University, Logan, UT 84322-4715, USA.
Lyons
J
J
Oh
H
H
Yu
Y
Y
Woltering
E A
EA
Greenway
F
F
York
D A
DA
D000263:Adenylate Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D003089:Colipases / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004792:Enzyme Precursors / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D066298:In Vitro Techniques; D009389:Neovascularization, Pathologic / Q000473:pathology / Q000517:prevention & control*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000032:analysis; D012265:Ribonucleotides / Q000494:pharmacology; D050507:Subcutaneous Fat, Abdominal / Q000098:blood supply / Q000187:drug effects; D014471:Umbilical Veins / Q000098:blood supply / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
D020533:Angiogenesis Inhibitors; D003089:Colipases; D004792:Enzyme Precursors; D007004:Hypoglycemic Agents; D012333:RNA, Messenger; D012265:Ribonucleotides; D042461:Vascular Endothelial Growth Factor A; D000620:Aminoimidazole Carboxamide; C037107:procolipase; D000263:Adenylate Kinase; C031143:AICA ribonucleotide