The overall objective of the applicant's research is to identify new strategies for treating cancer which through selectivity will combine effectiveness with low toxicity. Because growth of new blood vessels is critical for tumor growth, angiogenesis is an attractive target for cancer therapy. The applicant has previously shown that Vascular Endothelial Growth Factor (VEGF), a cytokine of central importance for tumor angiogenesis, induces endothelial cell expression of the integrins alpha1beta1 and alpha2beta1 while the expression of several other integrins is either reduced or unchanged. In order to determine the functional significance of integrin expression in VEGF-induced angiogenesis, the applicant went on to show that alpha1 and alpha2 blocking antibodies in combination substantially reduced neovascularization in a murine tumor model. These data provide a foundation for the applicant's hypothesis that induction of alpha1beta1 and alpha2beta1 is a fundamental mechanism by which VEGF promotes neovascularization. Others initially demonstrated the feasibility of blocking angiogenesis with Abs to avb3 and avb5. The applicant finds that VEGF induces EC expression of the avb3 integrin (3-4 fold) indicating that induction of avb3 is another mechanism by which VEGF promotes angiogenesis. Collectively, these observations suggest the additional hypothesis that combinations of antagonists which block a1b1, a2b1, and av integrins may offer synergistic potency leading to greater selectivity towards angiogenesis and reduced toxicity towards other biological processes. The applicant proposes two Specific Aims.
Specific Aim 1 is designed to investigate inhibition of angiogenesis and tumor growth in vivo by Abs which individually block a1b1 and a2b1 integrins and combinations of Abs which together block a1b1, a2b1, and av integrins. The applicant plans to employ the a1 and a2 antibodies separately to ascertain the consequences of blocking a1b1 and a2b1 individually, in comparison with blocking both simultaneously. In addition, the applicant plans complementary studies with a1 null mice to determine if antagonism of VEGF-driven angiogenesis by a1 Ab correlates with angiogenesis in the absence of a1 expression. The most significant findings will be tested in a mouse tumor model in order to determine if therapies involving a1 and/or a2 blocking Abs inhibit tumor growth.
Specific Aim 2 is directed at investigating mechanisms by which the a1b1 and a2b1 integrins together with VEGF regulate microvascular EC functions in vitro. Independently, these integrins and VEGF have been implicated in the regulation of cell proliferation, cell migration, and collagenase (MMP-1) expression. This suggests the hypothesis that a1b1, a2b1 and VEGF cooperate to promote these functions which are all critical to angiogenesis. To test this hypothesis, the applicant plans to investigate cooperativity between VEGF and a1b1/a2b1 in promoting 1) activation of cyclin E-CDK2 and EC proliferation, 2) EC migration, and 3) induction of collagenase expression. It is expected that the proposed experimental plan will provide new and fundamental information on the mechanisms by which VEGF promotes angiogenesis and will provide important evidence in favor of anti-cancer therapies based on antagonism of a1b1 and/or a2b1.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA077357-01
Application #
2564650
Study Section
Pathology A Study Section (PTHA)
Program Officer
Freeman, Colette S
Project Start
1998-05-05
Project End
2002-02-28
Budget Start
1998-05-05
Budget End
1999-02-28
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Beth Israel Deaconess Medical Center
Department
Type
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
02215
Nagy, Janice A; Senger, Donald R (2006) VEGF-A, cytoskeletal dynamics, and the pathological vascular phenotype. Exp Cell Res 312:538-48
Hoang, Mien V; Senger, Donald R (2005) In vivo and in vitro models of Mammalian angiogenesis. Methods Mol Biol 294:269-85
Davis, George E; Senger, Donald R (2005) Endothelial extracellular matrix: biosynthesis, remodeling, and functions during vascular morphogenesis and neovessel stabilization. Circ Res 97:1093-107
Hoang, Mien V; Whelan, Mary C; Senger, Donald R (2004) Rho activity critically and selectively regulates endothelial cell organization during angiogenesis. Proc Natl Acad Sci U S A 101:1874-9
Hong, Young-Kwon; Lange-Asschenfeldt, Bernhard; Velasco, Paula et al. (2004) VEGF-A promotes tissue repair-associated lymphatic vessel formation via VEGFR-2 and the alpha1beta1 and alpha2beta1 integrins. FASEB J 18:1111-3
Liu, Yanqiu; Senger, Donald R (2004) Matrix-specific activation of Src and Rho initiates capillary morphogenesis of endothelial cells. FASEB J 18:457-68
Whelan, Mary C; Senger, Donald R (2003) Collagen I initiates endothelial cell morphogenesis by inducing actin polymerization through suppression of cyclic AMP and protein kinase A. J Biol Chem 278:327-34
Perruzzi, Carole A; de Fougerolles, Antonin R; Koteliansky, Victor E et al. (2003) Functional overlap and cooperativity among alphav and beta1 integrin subfamilies during skin angiogenesis. J Invest Dermatol 120:1100-9
Senger, Donald R; Perruzzi, Carole A; Streit, Michael et al. (2002) The alpha(1)beta(1) and alpha(2)beta(1) integrins provide critical support for vascular endothelial growth factor signaling, endothelial cell migration, and tumor angiogenesis. Am J Pathol 160:195-204
Senger, D R; Van De Water, L (2000) VEGF expression by epithelial and stromal cell compartments: resolving a controversy. Am J Pathol 157:3-Jan