Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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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)

The enzyme beta1,4-N-acetylgalactosaminyltransferase III (beta4GalNAc-T3) exhibits in vitro activity of synthesizing N,N'-diacetyllactosediamine, GalNAcbeta1,4GlcNAc. Here, we investigate the expression of beta4GalNAc-T3 in primary colon tumors and the effects of its overexpression on HCT116 colon cancer cells. Real-time reverse transcription-PCR showed that the expression of beta4GalNAc-T3 was up-regulated in 72.5% (n = 40) of primary colon tumors compared with their normal counterparts. beta4GalNAc-T3 overexpression resulted in enhanced cell-extracellular matrix adhesion, migration, anchorage-independent cell growth, and invasion of colon cancer cells. Moreover, beta4GalNAc-T3 overexpression increased tumor growth and metastasis and decreased survival of tumor-bearing nude mice. beta4GalNAc-T3 overexpression showed increased tyrosine phosphorylation of focal adhesion kinase and paxillin Y118 as well as increased extracellular signal-regulated kinase phosphorylation. These results suggest that up-regulation of beta4GalNAc-T3 may play a critical role in promoting tumor malignancy and that integrin and mitogen-activated protein kinase signaling pathways could be involved in the underlying mechanism.
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PMID:Beta1,4-N-acetylgalactosaminyltransferase III enhances malignant phenotypes of colon cancer cells. 1757 16

The progression of human cancer is characterized by a process of tumor cell motility, invasion, and metastasis to distant sites, requiring the cancer cells to be able to survive the apoptotic pressures of anchorage-independent conditions. One of the critical tyrosine kinases linked to these processes of tumor invasion and survival is the focal adhesion kinase (FAK). FAK was first isolated from human tumors, and FAK mRNA was found to be upregulated in invasive and metastatic human breast and colon cancer samples. Recently, the FAK promoter was cloned, and it has been found to contain p53-binding sites. p53 inhibits FAK transcription, and recent data show direct binding of FAK and p53 proteins in vitro and in vivo. The structure of FAK and p53, proteins interacting with FAK, and the role of FAK in tumorigenesis and FAK-p53-related therapy are reviewed. This review focuses on FAK signal transduction pathways, particularly on FAK and p53 signaling, revealing a new paradigm in cell biology, linking signaling from the extracellular matrix to the nucleus.
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PMID:Focal adhesion kinase and p53 signaling in cancer cells. 1772 66

Physical forces including pressure, strain, and shear can be converted into intracellular signals that regulate diverse aspects of cell biology. Exposure to increased extracellular pressure stimulates colon cancer cell adhesion by a beta(1)-integrin-dependent mechanism that requires an intact cytoskeleton and activation of focal adhesion kinase (FAK) and Src. alpha-Actinin facilitates focal adhesion formation and physically links integrin-associated focal adhesion complexes with the cytoskeleton. We therefore hypothesized that alpha-actinin may be necessary for the mechanical response pathway that mediates pressure-stimulated cell adhesion. We reduced alpha-actinin-1 and alpha-actinin-4 expression with isoform-specific small interfering (si)RNA. Silencing of alpha-actinin-1, but not alpha-actinin-4, blocked pressure-stimulated cell adhesion in human SW620, HT-29, and Caco-2 colon cancer cell lines. Cell exposure to increased extracellular pressure stimulated alpha-actinin-1 tyrosine phosphorylation and alpha-actinin-1 interaction with FAK and/or Src, and enhanced FAK phosphorylation at residues Y397 and Y576. The requirement for alpha-actinin-1 phosphorylation in the pressure response was investigated by expressing the alpha-actinin-1 tyrosine phosphorylation mutant Y12F in the colon cancer cells. Expression of Y12F blocked pressure-mediated adhesion and inhibited the pressure-induced association of alpha-actinin-1 with FAK and Src, as well as FAK activation. Furthermore, siRNA-mediated reduction of alpha-actinin-1 eliminated the pressure-induced association of alpha-actinin-1 and Src with beta(1)-integrin receptor, as well as FAK-Src complex formation. These results suggest that alpha-actinin-1 phosphorylation at Y12 plays a crucial role in pressure-activated cell adhesion and mechanotransduction by facilitating Src recruitment to beta(1)-integrin, and consequently the association of FAK with Src, to enhance FAK phosphorylation.
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PMID:Alpha-actinin-1 phosphorylation modulates pressure-induced colon cancer cell adhesion through regulation of focal adhesion kinase-Src interaction. 1789 32

Micro-environmental clues, including the biophysical interpretation of the extracellular matrix, are critical to proliferation, apoptosis and migration. Here, we show that metastatic human colon cancer cell lines display altered matrix interaction. Interaction of colon cancer cells with collagen I depends on integrins (mainly alpha(1)/beta(1)) but metastatic cells display delayed spreading and reduced extension of lamellipodia. In addition, cells show defective strengthening of integrin-cytoskeleton linkages upon mechanical stimulation, as determined by laser trapping experiments and binding of large beads to the cell surface. However, adhesion to pliable surfaces is ameliorated in metastatic variants. These changes are caused by constitutive activation of focal adhesion kinase (FAK) and can be modulated by changing expression and/or activity of FAK via RNA-interference or expression of inhibitory constructs, respectively. In addition, consistent with defective strengthening of integrin-cytoskeleton linkages, metastatic cell lines show reduced random motility. Taken together these data suggest that constitutive activation of FAK causes defects in spreading, reinforcement of integrin-cytoskeleton linkages and migration and at the same time could ameliorate the adhesion of metastatic cells to suboptimal surfaces.
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PMID:Focal adhesion kinase mediates defects in the force-dependent reinforcement of initial integrin-cytoskeleton linkages in metastatic colon cancer cell lines. 1790 48

The aim of this investigation was to evaluate the chemopreventative/antiproliferative potential of a grape seed proanthocyanidin extract (GSPE) against colon cancer cells (CaCo2 cells) and to investigate its mechanism of action. GSPE (10-100 microg/ml) significantly inhibited cell viability and increased apoptosis in CaCo2 cells, but did not alter viability in the normal colon cell line (NCM460). The increased apoptosis observed in GSPE-treated CaCo2 cells correlated with an attenuation of PI3-kinase (p110 and p85 subunits) and decreased PKB Ser(473) phosphorylation. GSPE might thus exert its beneficial effects by means of increased apoptosis and suppression of the important PI3-kinase survival-related pathway.
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PMID:Proanthocyanidin from grape seeds inactivates the PI3-kinase/PKB pathway and induces apoptosis in a colon cancer cell line. 1792 79

Increased src tyrosine kinase expression and activity has been associated with colon cancer cell invasion and survival. Several signaling pathways are involved in the oncogenic activation of src during the adenoma to carcinoma progression and cellular invasion. In the present study, the synthetic ether lipid analog ET-18-OMe was shown to promote invasion of HCT-8/S11 colon cancer cells into collagen type I through the concomitant activation of src by phosphorylation at Tyr416 (5-30 min) in alpha1-integrin immunoprecipitates containing the integrin binding proteins talin and paxillin, as well as the phoshorylated and activated forms of focal adhesion kinase (FAK) at Tyr397 (a FAK kinase activation signal), Tyr576 and Tyr861. This was associated with the lateral redistribution of alpha1-integrins in focal aggregates and persistent activation of the p130Cas/JNK pathways at 5-30 min, with the subsequent induction and activation of the matrix metalloproteinases MMP-2 and MMP-9 (2-12 h). These activated molecular scaffolds and signaling cascades were not observed in immunoprecipitates of alpha2- and beta1-integrins, and tetraspanin CD9, an invasion and metastasis suppressor linked to integrins and FAK signaling. Our data demonstrate that the lateral redistribution and clustering of alpha1-integrins results in the recruitment of the FAK/src motility-promoting signaling complex involved in cancer cell invasion. Disruption of this proinvasive pathway was accomplished by the dominant negative mutant of src (K295R, kinase dead), src pharmacological inhibitor (PP1) and alpha1-integrin function blocking antibodies. These findings support the notion that the alpha1-integrin- and src-dependent signalosome is a relevant therapeutic target against tumor progression in colon cancer patients.
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PMID:Activation of the FAK-src molecular scaffolds and p130Cas-JNK signaling cascades by alpha1-integrins during colon cancer cell invasion. 1798 77

We recently showed that inhibition of heat shock protein 90 (Hsp90) decreases tumor growth and angiogenesis in gastric cancer through interference with oncogenic signaling pathways. However, controversy still exists about the antimetastatic potential of Hsp90 inhibitors. Moreover, in vitro studies suggested that blocking Hsp90 could overcome p53-mediated resistance of cancer cells to oxaliplatin. We therefore hypothesized that blocking oncogenic signaling with a Hsp90 inhibitor would impair metastatic behavior of colon cancer cells and also improve the efficacy of oxaliplatin in vivo. Human colon cancer cells (HCT116, HT29, and SW620) and the Hsp90 inhibitor 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG) were used for experiments. In vitro, 17-DMAG substantially inhibited phosphorylation of epidermal growth factor receptor, c-Met, and focal adhesion kinase, overall resulting in a significant decrease in cancer cell invasiveness. Importantly, 17-DMAG led to an up-regulation of the transcription factor activating transcription factor-3, a tumor suppressor and antimetastatic factor, on mRNA and protein levels. In a cell death ELISA, 17-DMAG markedly induced apoptosis in both p53-wt and p53-deficient cells. In vivo, 17-DMAG significantly reduced tumor growth and vascularization. Furthermore, blocking Hsp90 reduced hepatic tumor burden and metastatic nodules in an experimental model of hepatic colon cancer growth. Importantly, combining oxaliplatin with 17-DMAG in vivo significantly improved growth inhibitory and proapoptotic effects on p53-deficient cells, compared with either substance alone. In conclusion, inhibition of Hsp90 abrogates the invasive properties of colon cancer cells and modulates the expression of the antimetastatic factor activating transcription factor-3. Hence, targeting Hsp90 could prove valuable for treatment of advanced colorectal cancer by effectively inhibiting colon cancer growth and hepatic metastasis and improving the efficacy of oxaliplatin.
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PMID:Blocking heat shock protein-90 inhibits the invasive properties and hepatic growth of human colon cancer cells and improves the efficacy of oxaliplatin in p53-deficient colon cancer tumors in vivo. 1802 73

Endocytic pathways have been implicated in polyamine transport in mammalian cells, but specific mechanisms have not been described. We have shown that expression of a dominant negative (DN) form of the GTPase Dynamin, but not Eps15, diminished polyamine uptake in colon cancer cells indicating a caveolar and nonclathrin uptake mode. Polyamines co-sediment with lipid raft/caveolin-1 rich fractions, of the plasma membrane in a sucrose density gradient. Knock down of caveolin-1 significantly increased polyamine uptake. Conversely, ectopic expression of this protein resulted in diminished polyamine uptake. We also found that presence of an activated K-RAS oncogene significantly increased polyamine uptake by colon cancer cells. This effect is through an increase in caveolin-1 phosphorylation at tyrosine residue 14. Caveolin-1 is a negative regulator of caveolar endocytosis and phosphorylation in a K-RAS dependent manner leads to an increase in caveolar endocytosis. In cells expressing wild type K-RAS, addition of exogenous uPA was sufficient to stimulate caveolar endocytosis of polyamines. This effect was abrogated by the addition of a SRC kinase inhibitor. These data indicate that polyamine transport follows a dynamin-dependent and clathrin-independent endocytic uptake route, and this route is positively regulated by the oncogenic expression of K-RAS in a caveolin-1 dependent manner.
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PMID:Activated K-RAS increases polyamine uptake in human colon cancer cells through modulation of caveolar endocytosis. 1817 34

Peroxisome proliferator-activated receptor gamma (PPAR gamma) are members of the largest nuclear hormone receptor family of transcription factors (1). PPAR gamma (PPARgamma) plays an important role in adipogenesis, control of sensitivity to insulin, inflammation and atherosclerosis but recent studies also suggest that PPARgamma is involved in cell cycle withdrawal. PPARgamma can promote cell differentiation, exert an antiproliferative action and inhibit angiogenesis (2, 3). However, there are studies showing that activation of PPARgamma promotes the development of colon cancer (4). These data are in sharp contrast with studies that attribute anticancer effects to PPARgamma in gastrointestinal malignancies. Probably, the action of PPARgamma on cell cycle and proliferation depends on the cell type and presence of other stimuli that predispose cells to cancer development. Amidated and non-amidated gastrins may play an important role in the proliferation and carcinogenesis of GI cancers. It is known that gastrin peptides activate phosphorylation of Protein Kinase B (PKB/Akt) and anti-apoptotic signalling but there is little known about the link between gastrins and PPARgamma receptors in relation to apoptosis.
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PMID:Transcriptional upregulation of gastrin in response to peroxisome proliferator-activated receptor gamma agonist triggers cell survival pathways. 1819 88

Kallikreins are secreted proteases that may play a functional role and/or serve as a serum biomarker for the presence or progression of certain types of cancers. Kallikrein 6 (KLK6) has been shown to be upregulated in several types of cancers, including colon. The aims of this study were to elucidate pathways that influence KLK6 gene expression and KLK6 protein secretion in the HCT116 human colon cancer cells. Our data indicate a central role for caveolin-1 (CAV-1), the main structural protein of caveolae, in both KLK6 gene expression and protein secretion. Sucrose gradient subcellular fractionation reveals that CAV-1 and KLK6 colocalize to lipid raft domains in the plasma membrane of HCT116 cells. Furthermore, we show that CAV-1, although it does not directly interact with the KLK6 molecule, enhances KLK6 secretion from the cells. Deactivation of CAV-1, through SRC-mediated phosphorylation, decreased KLK6 secretion. We also demonstrate that, in colon cancer cells, CAV-1 increased the amount of phosphorylated AKT in cells by inhibiting the activity of the AKT-negative regulators PP1 and PP2A. This study demonstrates that proteins such as CAV-1 and AKT, which are known to be altered in colon cancer, affect KLK6 expression and KLK6 secretion.
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PMID:Caveolin-1-mediated expression and secretion of kallikrein 6 in colon cancer cells. 1828 36


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