The anti-inflammatory cytokine interleukin 19 is expressed by and angiogenic for human endothelial cells.

OBJECTIVE: To characterize the expression and function of interleukin (IL) 19, a recently described T-helper 2 anti-inflammatory IL, on endothelial cell (EC) pathophysiological features. METHODS AND RESULTS: The expression and effects of anti-inflammatory ILs on EC activation and development of angiogenesis are uncharacterized. We demonstrate by immunohistochemistry and immunoblot that IL-19 is expressed in inflamed, but not normal, human coronary endothelium and can be induced in cultured human ECs by serum and basic fibroblast growth factor. IL-19 is mitogenic and chemotactic, and it promotes EC spreading. IL-19 activates the signaling proteins STAT3, p44/42, and Rac1. In functional ex vivo studies, IL-19 promotes cordlike structure formation of cultured ECs and enhances microvessel sprouting in the mouse aortic ring assay. IL-19 induces tube formation in gelatinous protein (Matrigel) plugs in vivo. CONCLUSIONS: To our knowledge, these data are the first to report expression of the anti-inflammatory agent, IL-19, in ECs; and the first to indicate that IL-19 is mitogenic and chemotactic for ECs and can induce the angiogenic potential of ECs.

Formation of tissue factor-factor VIIa-factor Xa complex induces activation of the mTOR pathway which regulates migration of human breast cancer cells.

Tissue factor (TF) is a transmembrane glycoprotein that initiates blood coagulation when complexed with activated factor VII (FVIIa). TF is constitutively expressed in a variety of tumor cells and has been implicated in cellular signaling, angiogenesis, and tumor progression. Formation of TF-FVIIa complex and generation of downstream coagulation proteases, including activated factor X (FXa) and thrombin, initiate signaling by activation of protease-activated receptors (PARs). We have previously shown that TF-FVIIa-Xa complex formation promotes phosphorylation of p44/42 mitogen-activated protein kinase and Akt/protein kinase B in human breast cancer cells. In the present study, we show that formation of TF-FVIIa-FXa complex induces phosphorylation of mammalian target of rapamycin (mTOR) and p70 S6 kinase in a human breast cancer cell line, Adr-MCF-7. Activation of the mTOR pathway, which is probably mediated by PAR1 and/or PAR2, was associated with enhanced cell migration, a key step in the metastatic cascade. Inhibition of this pathway with the specific mTOR inhibitor, rapamycin, markedly decreased cell migration induced by formation of TF-FVIIa-FXa complex. These studies suggest that TF-FVIIa-mediated signaling modulates mTOR pathway activation, which regulates in part breast cancer cell migration. Targeting the TF-mediated cell signaling pathway might represent a novel strategy for the treatment of breast cancer.

Domain 5 of cleaved high molecular weight kininogen inhibits endothelial cell migration through Akt.

Domain 5 (D5) of cleaved high molecular weight kininogen (HKa) inhibits angiogenesis in vivo and endothelial cell migration in vitro, but the cell signaling pathways involved in HKa and D5 inhibition of endothelial cell migration are incompletely delineated. This study examines the mechanism of HKa and D5 inhibition of two potent stimulators of endothelial cell migration, sphingosine 1-phosphate (S1P) and vascular endothelial growth factor (VEGF), that act through the P13-kinase-Akt signaling pathway. HKa and D5 inhibit bovine pulmonary artery endothelial cell (BPAE) or human umbilical vein endothelial cell chemotaxis in the modified-Boyden chamber in response toVEGF or S1P. The inhibition of migration by HKa is reversed by antibodies to urokinase-type plasminogen activator receptor. Both HKa and D5 decrease the speed of BPAE cell migration and alter the morphology in live, time-lapse microscopy after stimulation with S1P or VEGF. HKa and D5 reduce the localization of paxillin to the focal adhesions after S1P and VEGF stimulation. To better understand the intracellular signaling pathways, we examined the effect of HKa on the phosphorylation of Akt and its downstream effector, GSK-3alpha HKa and D5 inhibit phosphorylation of Akt and GSK-3alpha after stimulation withVEGF and S1P. Inhibitors of Akt and P13-kinase, the upstream activator of Akt, block endothelial cell migration and disrupt paxillin localization to the focal adhesions after stimulation with VEGF and S1P. Therefore we suggest that HKa through its D5 domain alters P13-kinase-Akt signaling to inhibit endothelial cell migration through alterations in the focal adhesions.

c-Cbl regulates migration of v-Abl-transformed NIH 3T3 fibroblasts via Rac1.

Cellular events like cell adhesion and migration involve complex rearrangements of the actin cytoskeleton. We have previously shown that the multidomain adaptor protein c-Cbl facilitates actin cytoskeletal reorganizations that result in the adhesion of v-Abl-transformed NIH 3T3 fibroblasts. In this report, we demonstrate that c-Cbl also enhances migration of v-Abl-transformed NIH 3T3 fibroblasts. This effect of c-Cbl depends on its tyrosine phosphorylation, specifically on phosphorylation of its Tyr-731, which is required for binding of PI-3' kinase to c-Cbl. Furthermore, we demonstrate that the effect of c-Cbl on migration of v-Abl-transformed fibroblasts is mediated by active PI-3' kinase and the small GTPase Rac1. Our results also indicate that ubiquitin ligase activity of c-Cbl is required, while spatial localization of c-Cbl to the pseudopodia is not required for the observed effects of c-Cbl on cell migration.

Tyrosine phosphorylation of paxillin, FAK, and p130CAS: effects on cell spreading and migration.

Integrins are transmembrane receptors that mediate cell attachment to the substrate. At the cytoplasmic surface of the integrin, cytoskeletal proteins cluster into focal adhesions. The focal adhesions contain multiple proteins that provide a structural and signaling complex inside the cell. This review focuses on three of the cytoskeletal components of the focal adhesion, paxillin, FAK, and p130CAS, that are phosphorylated and play a regulatory role in cell spreading and cell migration. A brief discussion is included of tyrosine phosphorylation of the integrin in relation to localization and phosphorylation of these cytoskeletal proteins. The phosphorylation of integrins and cytoskeletal proteins regulates localization and downstream signaling with profound effects on cell movement.