Antagonism of VEGF-A–induced increase in vascular permeability by an integrin α3β1-Shp-1-cAMP/PKA pathway

Abstract

In cancer, VEGF-induced increase in vascular permeability results in increased interstitial pressure, reducing perfusion and increasing hypoxia, which reduce delivery of chemotherapeutic agents and increase resistance to ionizing radiation. Here, we show that both TIMP-2 and Ala ؉ TIMP-2, a TIMP-2 mutant without matrix metalloproteinase inhibitory activity, antagonize the VEGF-A-induced increase in vascular permeability, both in vitro and in vivo. Like other agents known to preserve endothelial barrier function, TIMP-2 elevates cytosolic levels of cAMP and increases cytoskeletal-associated vascular endothelial cadherin in human microvascular endothelial cells. All of these effects are completely ablated by selective knockdown of integrin ␣3␤1 expression, expression of a dominant negative protein tyrosine phosphatase Shp-1 mutant, administration of the protein tyrosine phosphatase inhibitor orthovanadate, or the adenylate cyclase inhibitor SQ22536. This TIMP-2-mediated inhibition of vascular permeability involves an integrin ␣3␤1-Shp-1-cAMP/protein kinase A-dependent vascular endothelial cadherin cytoskeletal association, as evidenced by using siRNAs to integrin ␣3␤1 and Shp-1, or treatment with Shp-1 inhibitor NSC87877 and protein kinase A inhibitor H89. Our results demonstrate the potential utility for TIMP-2 in cancer therapy through "normalization" of vascular permeability in addition to previously described antiangiogenic effects. (Blood. 2012;120(24):4892-4902) IntroductionTumor-associated angiogenesis is critical for tumor progression and metastasis. The central role of vascular endothelial growth factor-A (VEGF-A) in this process is evidenced by the development and approval of bevacizumab, a VEGF-A neutralizing antibody, for therapy in several human cancers. VEGF-A-induced angiogenesis is often accompanied by increased vascular permeability, which can result in fibrin deposition and may facilitate tumor cell extravasation enhancing metastasis formation. 1 The resulting vascular leak has also been shown to increase interstitial pressure within the tumor, decrease tumor blood flow, and hinder drug delivery to the tumor. Indeed, it has been proposed that VEGF-axis targeted therapies may result in "normalization" of tumor vasculature improving chemotherapeutic delivery and decreasing hypoxia, resulting in enhanced radiosensitivity. 2,3 Vascular permeability can be modulated by the phosphorylation, cleavage, and internalization of vascular endothelial (VE)-cadherin. [4][5][6] Tyrosine phosphorylation of the cadherin-catenin complexes is regulated by the activities of protein tyrosine phosphatases and src-family kinases. 7-11 Inhibition of tyrosine phosphorylation of VE-cadherin increases the stability of adherens junctions and improves vascular barrier function. Matrix metalloproteinase (MMP)-mediated cleavage of VE-cadherin may promote vascular permeability and cell proliferation by dissociating cadherin-catenin complex and disrupting cell-cell adhesion. [12][13][14][15] In contrast, it is widely recognized t...

PKA turnover by the REGγ-proteasome modulates FoxO1 cellular activity and VEGF-induced angiogenesis

“…However, there are also several mechanisms involved in PKA-mediated negative regulation of angiogenesis. Activation of PKA signaling can not only attenuate VEGF signaling in physiological conditions by blocking Raf activation [21] or through their actions on pp60Src [23], but also prohibit VEGF-induced increase in vascular permeability during cancer progression [22]. Paradoxically, distinct from previous demonstration that PKA promotes VEGF secretion, PKA may inhibit VEGF production by antagonizing Rap1 to regulate tumorstromal induction of angiogenesis in prostate cancer [24].…”

“…On the contrary, PKA antagonizes angiogenesis when the exogenous VEGF stimulation is involved [21–23]. Pharmacologic or genetic activation of PKA inhibits cell migration in endothelial and other cells [22, 26, 27]. Indeed, PKA plays a key role in the regulation of vascular sprouting by stimulating ECs adhesion and inhibiting cell migration [23], yet the molecular mechanism is only partially understood.…”

99mTc-labeled bevacizumab for detecting atherosclerotic plaque linked to plaque neovascularization and monitoring antiangiogenic effects of atorvastatin treatment in ApoE−/− mice

“…Prior studies have demonstrated that VEGF-A upregulation results in an increased permeability of vascular endothelial cell which caused immature microvessels 11, 12 . VEGF-A, the main proangiogenic isoform of the family, binds primarily to VEGF receptor (VEGFR)-1 and VEFGR-2 13 .…”

Ligularia fischeri inhibits endothelial cell proliferation, invasion and tube formation through the inactivation of mitogenic signaling pathways and regulation of vascular endothelial cadherin distribution and matrix metalloproteinase expression

“…Distribution of VE-cadherin at cell-cell contacts has been reported to enhance the stability of adherens junctions, resulting in maintenance of endothelial barrier function (9,10). Angiogenic factors such as VEGF-A disrupt the loss of VE-cadherin from the endothelial cell surfaces and induces endothelial cell responses such as permeability, proliferation, invasion and tube formation (13,14).…”

“…Matrix metalloproteinases (MMPs) play important roles in tissue remodeling by degrading extracellular matrix (ECM) components and cell surface molecules, leading to angiogenic responses associated with cancer growth and progression (6)(7)(8). MMP-mediated cleavage of vascular endothelial (VE)-cadherin in cell surfaces may promote vascular permeability, proliferation, invasion and capillary-like structure formation by dissociating cadherin-catenin complex and disrupting cell-cell adhesion (9)(10)(11)(12)(13)(14). The activities of these MMPs are regulated by endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs) (15).…”