title: Differential involvement of vascular endothelial growth factor in the survival of hypoxic colon cancer cells.
abstract: The recent approval of bevacizumab (Avastin), a humanized anti-vascular endothelial growth factor (VEGF) monoclonal antibody, in combination with chemotherapy for the treatment of patients with metastatic colorectal cancer, has provided proof of principle of the efficacy of antiangiogenic strategies for cancer therapy. The activity of bevacizumab is primarily attributed to its ability to inhibit endothelial cell survival. Whether anti-VEGF strategies may also have a direct effect on cancer cell survival is poorly understood. We show that serum-starved colon cancer cells differentially respond to autocrine production of VEGF with the induction of hypoxia inducible factor-1 alpha (HIF-1 alpha) and survival under hypoxic conditions. Inhibition of VEGF or VEGF receptor 2 (VEGFR2)/KDR, but not VEGFR1/Flt-1, was sufficient to abrogate VEGF-mediated induction of HIF-1 alpha and survival in sensitive HCT116, but not in resistant HT29, colon cancer cells. These results provide evidence that a VEGF/KDR/HIF-1 alpha autocrine loop differentially mediates survival of hypoxic colon cancer cells, and they suggest that colon cancer cells may be intrinsically sensitive or resistant to anti-VEGF strategies, which may determine the therapeutic efficacy of bevacizumab.
authors.affiliation: Developmental Therapeutics Program, National Cancer Institute-Frederick, Frederick, Maryland 21702, USA.
authors.forename: Maura
authors.initials: M
authors.lastname: Calvani
authors.forename: Daniela
authors.initials: D
authors.lastname: Trisciuoglio
authors.forename: Cristina
authors.initials: C
authors.lastname: Bergamaschi
authors.forename: Robert H
authors.initials: RH
authors.lastname: Shoemaker
authors.forename: Giovanni
authors.initials: G
authors.lastname: Melillo
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002470:Cell Survival; D003110:Colonic Neoplasms / Q000098:blood supply*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D051966:Phospholipase C gamma / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000502:physiology*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D048049:Extracellular Signal-Regulated MAP Kinases; D051966:Phospholipase C gamma