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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Circulating levels of
hepatocyte growth factor
(
HGF
) and vascular endothelial growth factor (VEGF) are increased during acute lung injury; however, combined effects of
HGF
and VEGF on pulmonary endothelial cell (EC) permeability remain to be elucidated. We have previously shown differential remodeling of focal adhesions (FA) caused by barrier-protective and barrier-disruptive mechanical and chemical stimuli. This study examined a role of FA protein paxillin in the pulmonary EC barrier responses induced by
HGF
and VEGF. VEGF increased, but
HGF
decreased, pulmonary EC permeability. These effects were accompanied by differential patterns of site-specific phosphorylation of
focal adhesion kinase
(
FAK
) and paxillin and FA redistribution.
HGF
antagonized random FA formation caused by VEGF challenge and promoted FA accumulation at the cell periphery.
HGF
attenuated VEGF-induced paxillin redistribution, FA remodeling, and endothelial permeability. SiRNA-based paxillin knockdown attenuated VEGF-induced EC permeability, myosin light chain phosphorylation, and stress fiber and paracellular gap formation. Paxillin knockdown also decreased
HGF
-induced EC barrier enhancement and suppressed activation of Rac and its effector PAK1. Expression of paxillin-S(273) deficient on PAK1 phosphorylation site prevented
HGF
-induced cytoskeletal remodeling. These data show a dual role of paxillin in the
HGF
- and VEGF-mediated endothelial barrier regulation and suggest essential paxillin role in the modulation of Rac-Rho crosstalk. Our results also support a model of pulmonary EC barrier recovery during resolution of ALI via switch from VEGF to
HGF
signaling.
...
PMID:Paxillin is involved in the differential regulation of endothelial barrier by HGF and VEGF. 1866 39
Cancer invasion is an outcome of interactions of the cancer and the host cell. It is now becoming increasingly clear that ovarian hormones have a huge influence on such intercommunications in various types of cancers. Estrogen is known to aggravate the aggressiveness of the endometrial cancer whereas progesterone seems to act as a negative factor. Insight into the mode of ovarian hormonal actions could come from the studies of its regulation of the paracrine interactions between the endometrial cancer and the normal stromal cells during the cancer invasion. In this context, we report here that estrogen promotes the endometrial cancer invasion by inducing humoral interactions between the cancer and the stromal cells, i.e., estrogen stimulates tumor necrosis factor-alpha expression from the endometrial cancer cells, which, in turn, induces the stromal expression of
hepatocyte growth factor
(
HGF
), conferring the enhanced NK4 (
HGF
-antagonist/angiogenesis inhibitor)-sensitive invasion characteristic of the endometrial cancer cells. Additionally, we demonstrate a close correlation of the invasion of endometrial cancer cells with the expression and dimerization of integrin alpha(v)beta(5) as well as the activation of
focal adhesion kinase
as the consequences of paracrine interactions. Thus, understanding of paracrine interactions of cancer cells with host stromal cells can yield new insight into the architecture and function of cancer invasion and metastasis, leading to a development of a new cancer therapeutic intervention.
...
PMID:Endometrial cancer invasion depends on cancer-derived tumor necrosis factor-alpha and stromal derived hepatocyte growth factor. 1923 22
Hepatocyte growth factor
(
HGF
) plays a definitive role in invasive, angiogenic, and metastatic activities of tumor cells by binding to the c-Met receptor. NK4, a competitive antagonist for
HGF
and the c-Met receptor, prevents tumor cell growth and metastasis via its bifunctional properties to act as an
HGF
antagonist and angiogenesis inhibitor. In the present study, we investigated the inhibitory effectiveness of NK4 on hematogenous pulmonary metastasis of the CT26 murine colon cancer cell line, focusing on tumor cell adhesion to endothelial cells. In an in vitro adhesion assay,
HGF
facilitated adhesion of CT26 cells to a murine endothelial cell line (F-2) in a dose-dependent manner. Furthermore, the enhancing effect of
HGF
on CT26-F-2 cell interaction was blocked by NK4 as well as by anti-
HGF
antibody. Similarly,
HGF
-induced phosphorylation of
focal adhesion kinase
(
FAK
), downstream of integrin signaling, was reduced by NK4 and by anti-
HGF
antibody. However, distinct integrin expression on the surface of CT26 cells was not altered by
HGF
. In an in vivo experimental pulmonary metastasis assay, stable NK4 expression potently decreased the number of pulmonary metastatic foci. The NK4-induced suppression of pulmonary metastasis was partially reversed when
HGF
was intraperitoneally administered in an adhesive phase. These results suggest that NK4 could act on tumor cells to inhibit CT26 adhesion to endothelial cells by reducing
FAK
phosphorylation, which is regulated by inside-out
HGF
/c-Met signaling, and thereby suppress hematogenous pulmonary metastasis.
...
PMID:NK4, an HGF antagonist, prevents hematogenous pulmonary metastasis by inhibiting adhesion of CT26 cells to endothelial cells. 1923 48
We previously demonstrated that alpha3beta1 integrins are essential to
hepatocyte growth factor
(
HGF
)-independent branching tubulogenesis in Mardin-Darby Canine Kidney (MDCK) cells. However, the involvement of integrin downstream signaling molecules remains unclear. In the present study, we successfully isolated cell lines possessing different tubulogenic potentials from the MDCK cells; cyst clones (CA4, CA6) forming cystic structures when cultured in 0.3% type I collagen gel and mass clones (M610, M611, M612) forming aggregated masses. Cyst clones maintained cystic structure in 0.1% collagen gel, whereas mass clones spontaneously developed into tubules. Both clones exhibited various morphologies when cultured on a dish: cyst clones formed aggregated islands, while mass clones were more scattered and exhibited higher migration capacity. Among several focal adhesion machinery proteins examined, only the expression and phosphorylation level of
focal adhesion kinase
(
FAK
) in mass clones was higher than in cyst clones, while other proteins showed no obvious differences. However, overexpression of wild type
FAK
in CA6 cells did not facilitate branching tubule formation in 0.1% collagen gel. Targeted decrease in the expression level of
FAK
in M610 cells with the application of antisense cDNA resulted in a marked reduction of branching tubule formation in 0.1% collagen gel and showed a down-regulation of fibronectin assembly, which is known to promote tubulogenesis. In contrast, overexpression of wild type
FAK
in CA6 cells had no effect on fibronectin assembly. Taken together, our data demonstrates that
FAK
is required, but not sufficient for
HGF
-independent branching tubulogenesis in MDCK cells.
...
PMID:Requirement of focal adhesion kinase in branching tubulogenesis. 1927 69
NK4, a fragment of
hepatocyte growth factor
(
HGF
), exerts bifunctional action as a competitive antagonist against
HGF
and its receptor c-Met and an angiogenesis inhibitor. Here we studied the anti-angiogenic mechanism of NK4. In cultured human endothelial cells, NK4 inhibited DNA synthesis induced not only by
HGF
but also by either basic fibroblast growth factor or vascular endothelial growth factor. Even if c-Met expression was diminished by small interference RNA, NK4 inhibited basic fibroblast growth factor-induced DNA synthesis, indicating that anti-angiogenic action of NK4 is c-Met-independent. Affinity purification with NK4-immobilized beads revealed that NK4 binds to perlecan. Consistent with this, NK4 colocalized with perlecan in endothelial cells. Perlecan is a multidomain heparan sulfate proteoglycan that interacts with basement membrane components such as fibronectin. NK4 inhibited extracellular assembly of fibronectin, by which fibronectin-dependent endothelial cell spreading was inhibited by NK4. Knockdown of perlecan expression by small interference RNA significantly abrogated the inhibitory effect of NK4 on fibronectin assembly and cell spreading. In NK4-treated endothelial cells, tyrosine phosphorylation of
focal adhesion kinase
and Rac activation were reduced, whereas overexpression of activated Rac recovered the DNA synthesis in NK4-treated endothelial cells. These results indicate that the association between NK4 and perlecan impairs fibronectin assembly, thereby inhibiting anchorage-dependent signaling. The identified mechanism for angiostatic action provides further proof of significance for NK4 in the treatment of cancer and potentially for vascular regulation as well.
...
PMID:Angioinhibitory action of NK4 involves impaired extracellular assembly of fibronectin mediated by perlecan-NK4 association. 1955
The adaptor protein Crk mediates intracellular signaling related to cell motility and proliferation and is implicated in human tumorigenesis. The role of Crk in the growth of human sarcoma has remained unclear, however. The present study shows that Crk-induced activation of Src and subsequent signaling by p38 mitogen-activated protein kinase (MAPK) contribute to the enhanced proliferation of human synovial sarcoma cells. Depletion of Crk by RNA interference markedly inhibited proliferation of the synovial sarcoma cell lines HS-SYII, SYO-1, and Fuji as well as prevented anchorage-independent growth. Conversely, reconstitution with CrkII by authentic small interfering RNA-resistant Crk gene restored proliferation in Crk-silenced SYO-1 cells. Crk-depleted synovial sarcoma cells manifested enhanced transcriptional activity and expression of the p16(INK4A) gene, resulting in their accumulation in G(1) phase of the cell cycle. In response to
hepatocyte growth factor
stimulation, Crk prominently induced the tyrosine phosphorylation of Grb2-associated binder 1 through activation of Src and
focal adhesion kinase
, and the Src family kinase inhibitor PP2 almost completely inhibited the proliferation of SYO-1 cells. Crk also induced the phosphorylation of p38 MAPK, and SB203580, a p38 MAPK-specific inhibitor, increased expression of p16(INK4A) gene in SYO-1 cells. Furthermore, SB203580 or depletion of p38 MAPK by small interfering RNA suppressed both the phosphorylation of Akt triggered by
hepatocyte growth factor
and the proliferation of SYO-1 cells. These results suggest that Crk promotes proliferation of human synovial sarcoma cells through activation of Src and its downstream signaling by a novel p38 MAPK-Akt pathway, with these signaling molecules providing potent new targets for molecular therapeutics.
...
PMID:Adaptor protein Crk induces Src-dependent activation of p38 MAPK in regulation of synovial sarcoma cell proliferation. 1973 74
Ski is an oncoprotein that negatively regulates transforming growth factor (TGF)-beta signaling. It acts as a transcriptional co-repressor by binding to TGF-beta signaling molecules, Smads. Efficient TGF-beta signaling is facilitated by rapid proteasome-mediated degradation of Ski by TGF-beta. Here we report that Ski is phosphorylated by Akt/
PKB
kinase. Akt phosphorylates Ski on a highly conserved Akt motif at threonine 458 both in vitro and in vivo. The phosphorylation of Ski at threonine 458 is induced by Akt pathway activators including insulin, insulin-like growth factor-1, and
hepatocyte growth factor
. The phosphorylation of Ski causes its destabilization and reduces Ski-mediated inhibition of expression of another negative regulator of TGF-beta, Smad7. Induction of Smad7 levels leads to inactivation of TGF-beta receptors and TGF-beta signaling cascade, as indicated by reduced induction of TGF-beta target p15. Therefore, Akt modulates TGF-beta signaling by temporarily adjusting the levels of two TGF-beta pathway negative regulators, Ski and Smad7. These novel findings demonstrate that Akt pathway activation directly impacts TGF-beta pathway.
...
PMID:The phosphatidylinositol 3-kinase/Akt pathway regulates transforming growth factor-{beta} signaling by destabilizing ski and inducing Smad7. 1987 56
Netrin-4, a laminin-related secreted protein is an axon guidance cue recently shown essential outside of the nervous system, regulating mammary and lung morphogenesis as well as blood vascular development. Here, we show that Netrin-4, at physiologic doses, induces proliferation, migration, adhesion, tube formation and survival of human lymphatic endothelial cells in vitro comparable to well-characterized lymphangiogenic factors fibroblast growth factor-2 (FGF-2),
hepatocyte growth factor
(
HGF
), vascular endothelial growth factor-A (VEGF-A), and vascular endothelial growth factor-C (VEGF-C). Netrin-4 stimulates phosphorylation of intracellular signaling components Akt, Erk and S6, and their specific inhibition antagonizes Netrin-4-induced proliferation. Although Netrin receptors Unc5B and neogenin, are expressed by human lymphatic endothelial cells, suppression of either or both does not suppress Netrin-4-promoted in vitro effects. In vivo, Netrin-4 induces growth of lymphatic and blood vessels in the skin of transgenic mice and in breast tumors. Its overexpression in human and mouse mammary carcinoma cancer cells leads to enhanced metastasis. Finally, Netrin-4 stimulates in vitro and in vivo lymphatic permeability by activating small GTPases and Src family kinases/
FAK
, and down-regulating tight junction proteins. Together, these data provide evidence that Netrin-4 is a lymphangiogenic factor contributing to tumor dissemination and represents a potential target to inhibit metastasis formation.
...
PMID:Netrin-4 induces lymphangiogenesis in vivo. 2040 33
Most prostate cancer-related deaths are due to advanced disease with patients with metastatic prostate cancer having a 5-year survival rate of only 34%. Overexpression of c-Met receptor tyrosine kinase has been highly associated with prostate cancer progression and metastasis. In the present studies, the effect of BMS-777607, a selective and potent small-molecule Met kinase inhibitor that has been advanced to clinical evaluation, on
hepatocyte growth factor
(
HGF
)-mediated cell functions and signaling pathways was evaluated in c-Met-expressing PC-3 and DU145 prostate cancer cells. BMS-777607 treatment had little effect on tumor cell growth but inhibited cell scattering activated by exogenous
HGF
, with almost complete inhibition at 0.5 micromol/L in PC-3 and DU145 cells. This agent also suppressed
HGF
-stimulated cell migration and invasion in a dose-dependent fashion (IC(50) < 0.1 micromol/L) in both cell lines. Mechanistically, nanomolar doses of BMS-777607 potently blocked
HGF
-stimulated c-Met autophosphorylation and downstream activation of Akt and extracellular signal-regulated kinase. In addition, both wortmannin and U0126, but not dasatinib, attenuated cell scattering and migration induced by
HGF
, suggesting the involvement of the phosphoinositide 3-kinase and mitogen-activated protein kinase pathways, but not of Src or
focal adhesion kinase
, in
HGF
-mediated motogenic effects. Taken together, these data indicate that the downregulation of c-Met signaling by BMS-777607 treatment can significantly disrupt key steps in the metastatic cascade, suggesting that such a targeting strategy may hold promise for the treatment of advanced prostate cancer.
...
PMID:BMS-777607, a small-molecule met kinase inhibitor, suppresses hepatocyte growth factor-stimulated prostate cancer metastatic phenotype in vitro. 2051 43
Semaphorins are secreted and membrane bound proteins that regulate axon guidance through receptors Plexins and neuropilins. Plexin B1, the Semaphorin 4D receptor, is a recently described tumor suppressor protein for melanoma. We recently showed that Plexin B1 abrogates activation of the oncogenic receptor, c-Met, by its ligand,
hepatocyte growth factor
(
HGF
), in melanoma. We have now investigated the effect of Plexin B1 on integrin-dependent pp125(
FAK
) activation, and the small GTP-binding protein Rho, in melanoma. Integrin receptors and Rho play critical roles in melanoma progression, through regulation of migration, proliferation and apoptosis. We engineered two human melanoma cell lines expressing Plexin B1 and analyzed integrin-dependent migration, integrin-dependent pp125(
FAK
) activation, and Rho activity. Results show that Plexin B1 abrogates integrin-dependent migration and activation of pp125(
FAK
). We also show that Rho activity is significantly reduced in cells expressing Plexin B1, and that Plexin B1 suppresses
HGF
-dependent Rho activation.
...
PMID:Plexin B1 inhibits integrin-dependent pp125FAK and Rho activity in melanoma. 2102 96
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