title: Drug resistance by evasion of antiangiogenic targeting of VEGF signaling in late-stage pancreatic islet tumors.
abstract: Function-blocking antibodies to VEGF receptors R1 and R2 were used to probe their roles in controlling angiogenesis in a mouse model of pancreatic islet carcinogenesis. Inhibition of VEGFR2 but not VEGFR1 markedly disrupted angiogenic switching, persistent angiogenesis, and initial tumor growth. In late-stage tumors, phenotypic resistance to VEGFR2 blockade emerged, as tumors regrew during treatment after an initial period of growth suppression. This resistance to VEGF blockade involves reactivation of tumor angiogenesis, independent of VEGF and associated with hypoxia-mediated induction of other proangiogenic factors, including members of the FGF family. These other proangiogenic signals are functionally implicated in the revascularization and regrowth of tumors in the evasion phase, as FGF blockade impairs progression in the face of VEGF inhibition.
authors.affiliation: Department of Biochemistry and Biophysics, Comprehensive Cancer Center, and Diabetes Center, University of California, San Francisco, San Francisco, California 94143, USA.
authors.forename: Oriol
authors.initials: O
authors.lastname: Casanovas
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hicklin
authors.forename: Gabriele
authors.initials: G
authors.lastname: Bergers
authors.forename: Douglas
authors.initials: D
authors.lastname: Hanahan
mesh_terms: D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D005346:Fibroblast Growth Factors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D007515:Islets of Langerhans / Q000473:pathology*; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000378:metabolism*; D040262:Receptors, Vascular Endothelial Growth Factor / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D042461:Vascular Endothelial Growth Factor A; D005346:Fibroblast Growth Factors; D040262:Receptors, Vascular Endothelial Growth Factor