UMLS:C0699790 - FACTA Search

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Query: UMLS:C0699790 (colon cancer)
28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms underlying the inflammatory and metastatic processes share a number of similar pathways, such as those involving adhesion, migration and extravasation. In this article, the effects of pro-inflammatory cytokines on metastatic-related activities of colon cancer cells were tested. The expression and biological activity of the proteoglycan CD44 in low (LS174T) and high metastatic (HM7) cell lines following exposure to TNFalpha and IL-8 were assessed. Treated cells expressed more CD44 splice variants (CD44v), while CD44 standard protein (CD44s) expression remained unchanged. Treatment with TNFalpha induced IL-8 secretion and IL-8 gene transcription in a time-dependent manner. Both cytokines enhanced the ability of the cells to adhere to the CD44-specific ligand hyaluronic acid, an effect that was specifically blocked by an anti-IL-8 antibody. These results suggest that the effect of TNFalpha on IL-8 is responsible for the regulation of the expression of CD44 isoforms. Additional experiments showed that neither of the cytokines tested regulate the expression of CD44 gene regulation via activation of a well-characterized specific 22-bp epidermal growth factor regulatory element present in the CD44 promoter sequence, suggesting that this is not the mechanism of activation. We conclude that immuno-modulatory mediators can modify the expression of cell-to-cell or cell-to-matrix adhesion proteins, implicated in the determination of phenotypes associated with aggressiveness and metastasis of colon cancer cells.
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PMID:TNFalpha and IL-8 regulate the expression and function of CD44 variant proteins in human colon carcinoma cells. 1209 Apr 73

Thalidomide has been shown to have both antiinflammatory and antiangiogenic effects in several diseases. However, its cellular target and mechanism of action are poorly understood. We investigated the action mechanism of thalidomide through the NFkappaB pathway. Thalidomide inhibited interleukin (IL) 1beta-induced NFkappaB transcriptional activation and IL-8 production in Caco-2 colon cancer cells. In addition, thalidomide suppressed NFkappaB nuclear translocation, IkappaB degradation, and NFkappaB-inducing kinase (NIK)-induced NFkappaB transcriptional activation. These results suggest that the molecular target of the effects of thalidomide may be IkappaB phosphorylation by IkappaB kinase (IKK), whose activation follows NIK activation and precedes IkappaB degradation in the NFkappaB pathway.
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PMID:Thalidomide suppresses the interleukin 1beta-induced NFkappaB signaling pathway in colon cancer cells. 1248 2

Lysophosphatidic acid (LPA) is a lipid mediator with diverse effects on various cells. Here, we investigated the effects of LPA on human colon carcinoma DLD1 cells. Northern blot analysis revealed that DLD1 highly expressed LPA1/Edg-2 but showed only low expression of LPA2/Edg-4 and no expression of LPA3/Edg-7 at the mRNA level. Western blot analysis revealed that DLD1 cells highly expressed LPA1 at the protein level. Using the Boyden chamber assay, LPA markedly increased DLD1 cell migration at concentrations as low as 10 nM, with maximum stimulation at 100 nM (3.6-fold increase). Checkerboard analysis indicated that LPA stimulated both the chemotactic and chemokinetic migration of DLD1 cells. LPA induced a dose-dependent increase in the proliferation of DLD1 cells (3.2-fold increase at 20 microM). Furthermore, LPA stimulated DLD1 cell adhesion to collagen type I (2.0-fold increase at 10 microM) and also stimulated the secretion of both vascular endothelial growth factor (1.4-fold increase at 20 microM) and interleukin 8 (19-fold increase at 20 microM) by ELISA. In contrast, as for matrix metalloproteinase, LPA had no significant effect on pro-matrix metalloproteinase-2 secretion and its activation, as measured by Western blot analysis. Thus, LPA, at concentrations that are present physiologically, enhanced DLD1 cell migration, proliferation, adhesion, and secretion of angiogenic factors, all of which are crucial for cancer metastasis. In comparison, other human colon carcinoma cells (HT29 and WiDR) exclusively expressed LPA2. LPA enhanced their proliferation and secretion of angiogenic factors, whereas LPA did not enhance migration or adhesion. Our results suggest that LPA acts as a potent stimulator of colon cancer progression, although the binding to LPA1 and LPA2 induces slightly different responses.
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PMID:Lysophosphatidic acid (LPA) enhances the metastatic potential of human colon carcinoma DLD1 cells through LPA1. 1267 Sep 25

Several studies reported linkage between bacterial infections and carcinogenesis. Streptococcus bovis was traditionally considered as a lower grade pathogen frequently involved in bacteremia and endocarditis. This bacterium became important in human health as it was shown that 25-80% of patients who presented a S.bovis bacteremia had also a colorectal tumor. Moreover, in previous experiments, we demonstrated that S.bovis or S.bovis wall extracted antigens (WEA) were able to promote carcinogenesis in rats. The aim of the present study was: (i) to identify the S.bovis proteins responsible for in vitro pro-inflammatory properties; (ii) to purify them; (iii) to examine their ability to stimulate in vitro IL-8 and COX-2 expression by human colon cancer cells; and (iv) to assess in vivo their pro-carcinogenic potential in a rat model of colon carcinogenesis. The purified S300 fraction, as determined by proteomic analysis, contained 72 protein spots in two-dimensional gel electrophoresis representing 12 different proteins able to trigger human epithelial colonic Caco-2 cells and rat colonic mucosa to release CXC chemokines (human IL-8 or rat CINC/GRO) and prostaglandins E2, correlated with an in vitro over-expression of COX-2. Moreover, these proteins were highly effective in the promotion of pre-neoplastic lesions in azoxymethane-treated rats. In the presence of these proteins, Caco-2 cells exhibited enhanced phosphorylation of the three classes of MAP kinases. Our results show a relationship between the pro-inflammatory potential of S.bovis proteins and their pro-carcinogenic properties, confirming the linkage between inflammation and colon carcinogenesis. These data support the hypothesis that colonic bacteria can contribute to cancer development particularly in chronic infection/inflammation diseases where bacterial components may interfere with cell function.
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PMID:Carcinogenic properties of proteins with pro-inflammatory activity from Streptococcus infantarius (formerly S.bovis). 1474 16

The NADPH oxidase 1 (Nox1) is a gp91(phox) homologue preferentially expressed in the colon. We have established primary cultures of guinea pig large intestinal epithelial cells giving 90% purity of surface mucous cells. These cells spontaneously released superoxide anion (O(2)(-)) of 160 nmol/mg protein/h and expressed the Nox1, p22(phox), p67(phox), and Rac1 mRNAs, but not the gp91(phox), Nox4, p47(phox), p40(phox), and Rac2 mRNAs. They also expressed novel homologues of p47(phox) and p67(phox) (p41(nox) and p51(nox), respectively). Human colon cancer cell lines (T84 and Caco2 cells) expressed the Nox1, p22(phox), p51(nox), and Rac1 mRNAs, but not the other NADPH component mRNAs, and secreted only small amounts of O(2)(-) (<2 nmol/mg protein/h). Cotransfection of p41(nox) and p51(nox) cDNAs in T84 cells enhanced PMA-stimulated O(2)(-) release 5-fold. Treatment of the transfected T84 cells with recombinant flagellin (rFliC) from Salmonella enteritidis further augmented the O(2)(-) release in association with the induction of Nox1 protein. The enhanced O(2)(-) production by cotransfection of p41(nox) and p51(nox) vectors further augmented the rFliC-stimulated IL-8 release from T84 cells. T84 cells expressed the Toll-like receptor 5, and rFliC rapidly phosphorylated TGF-beta-activated kinase 1 and TGF-beta-activated kinase 1-binding protein 1. A potent inhibitor for NF-kappaB (pyrrolidine dithiocarbamate) significantly blocked the rFliC-primed increase in O(2)(-) production and induction of Nox1 protein. These results suggest that p41(nox) and p51(nox) are involved in the Nox1 activation in surface mucous cells of the colon, and besides that, epithelial cells discern pathogenicities among bacteria to appropriately operate Nox1 for the host defense.
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PMID:Role of nicotinamide adenine dinucleotide phosphate oxidase 1 in oxidative burst response to Toll-like receptor 5 signaling in large intestinal epithelial cells. 1497 10

Recent epidemiological studies indicated risk reductions in ovarian cancer with consumption of acetaminophen or non-steroid anti-inflammatory drugs. Until now, there is not a systematic analysis, why these agents may reduce risk of ovarian cancer, as it has been performed to explain aspirin-reduction of colon cancer risk. This review tries to explain molecular mechanisms pertinent to acetaminophen- and NSAID-reduction of ovarian cancer. It is proposed that the major mechanism by these anti-inflammatory agents is a shared pathway dependent on the suppression of NF-kappaB activity, which may subsequently decrease transcription of growth factors, chemokines and proteases such as COX-2, VEGF, IL-8/CXCL8, MCP-1/CCL-2, MIP1alpha/CCL-3, tPA and uPA, which are shown to be elevated in ovarian carcinoma, and which play diverse roles such as inducing angiogenesis, invasion, autocrine growth loops and resistance to apoptosis. Besides these, specific mechanisms of action can be attributed to acetaminophen-reduction of ovarian cancer risk via I. Induction of specific reproductive atrophy due its sex-steroid resembling phenolic ring; II. Reduction of glutathione pools due to its NAPQI metabolite, which may play an important role for sterilizing pre-malignant ovarian lesions, since they are shown to lack proper levels of glutathione; III. Inhibition of tautomerization activity of MIF (macrophage migration inhibitory factor), which is shown to be released from ovarian cancer, and which is necessary for proper ovulation; IV. Inhibition of cytokine-induced and endothelia-origined cyclooxygenases. Except the chemosensitization studies, acetaminophen and NSAIDs should be investigated in animal models to test likely benefits in ovarian cancer, since most of their activity may origin from intervening with the cancer growth-stimulating inflammatory stimuli, rather than with the direct cellular toxicity.
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PMID:NF-kappaB, macrophage migration inhibitory factor and cyclooxygenase-inhibitions as likely mechanisms behind the acetaminophen- and NSAID-prevention of the ovarian cancer. 1525 53

Interleukin-8 (IL-8) has been reported to promote tumor cell growth in colon cancer cells after binding to its receptors, which are members of the G-protein coupled receptor (GPCR) family. Recent studies demonstrated that stimulation of GPCR can induce shedding of epidermal growth factor (EGF) ligands via activation of a disintegrin and metalloprotease (ADAM), with subsequent transactivation of the EGF receptor (EGFR). In this study, we investigated mechanisms of cell proliferation and migration stimulated by IL-8 in a human colon carcinoma cell line (Caco2). IL-8 increased DNA synthesis of Caco2 in a dose dependent manner and this was inhibited by ADAM, EGFR kinase, and MEK inhibitors. IL-8 transiently induced EGFR tyrosine phosphorylation after 5-90 min and this was completely inhibited by ADAM inhibitor. Neutralizing antibody against HB-EGF as a key ligand for EGFR also blocked transactivation of EGFR and cell proliferation by IL-8. Since IL-8-induced cell migration was further suppressed by the ADAM inhibitor and the HB-EGF neutralizing antibody, our data indicate that IL-8 induces cell proliferation and migration by an ADAM-dependent pathway, and that HB-EGF plays an important role as the major ligand for this pathway.
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PMID:IL-8 promotes cell proliferation and migration through metalloproteinase-cleavage proHB-EGF in human colon carcinoma cells. 1574 28

A major component in green tea, epigallocatechin-3-gallate (EGCG), is reported to interfere with different steps of a number of inflammatory pathways. After oral administration, EGCG is retained in the gastrointestinal tract, where it is thought to exert preventive functions against inflammatory bowel disease and colon cancer. In this study, the human colon adenocarcinoma cell lines HT29 and T84 were used to investigate the effect of EGCG on intestinal inflammation. HT29 and T84 cells were stimulated with tumor necrosis factor (TNF)-alpha to induce the inflammatory condition and to trigger the inflammatory cascade in vitro and treated with EGCG to study its effect on inflammatory processes. The secretion of the chemokines interleukin (IL)-8, macrophage inflammatory protein (MIP)-3alpha, and prostaglandin E2 (PGE2) was determined by enzyme-linked immunosorbent assay. The gene expression level was measured by quantitative real-time polymerase chain reaction. Treatment of TNF-alpha-stimulated HT29 cells with EGCG dose-dependently inhibited the synthesis of IL-8, MIP-3alpha, and PGE2. Treatment with EGCG also inhibited the production of IL-8 and MIP-3alpha in TNF-alpha-stimulated T84 cells. Gene expression analysis in both HT29 and T84 cells revealed that EGCG down-regulates genes involved in inflammatory pathways. This study shows that EGCG acts broadly on the production of chemokines and PGE2 in the chemokine and eicosanoid pathways of colon epithelial cells. Therefore, EGCG might prove useful for the prevention and/or attenuation of colonic disorders.
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PMID:Epigallocatechin-3-gallate impairs chemokine production in human colon epithelial cell lines. 1612 9

Hypoxia inducible factor-1 (HIF-1) is considered a crucial mediator of the cellular response to hypoxia through its regulation of genes that control angiogenesis. It represents an attractive therapeutic target in colon cancer, one of the few tumor types that shows a clinical response to antiangiogenic therapy. But it is unclear whether inhibition of HIF-1 alone is sufficient to block tumor angiogenesis. In HIF-1alpha knockdown DLD-1 colon cancer cells (DLD-1(HIF-kd)), the hypoxic induction of vascular endothelial growth factor (VEGF) was only partially blocked. Xenografts remained highly vascularized with microvessel densities identical to DLD-1 tumors that had wild-type HIF-1alpha (DLD-1(HIF-wt)). In addition to the preserved expression of VEGF, the proangiogenic cytokine interleukin (IL)-8 was induced by hypoxia in DLD-1(HIF-kd) but not DLD-1(HIF-wt) cells. This induction was mediated by the production of hydrogen peroxide and subsequent activation of NF-kappaB. Furthermore, the KRAS oncogene, which is commonly mutated in colon cancer, enhanced the hypoxic induction of IL-8. A neutralizing antibody to IL-8 substantially inhibited angiogenesis and tumor growth in DLD-1(HIF-kd) but not DLD-1(HIF-wt) xenografts, verifying the functional significance of this IL-8 response. Thus, compensatory pathways can be activated to preserve the tumor angiogenic response, and strategies that inhibit HIF-1alpha may be most effective when IL-8 is simultaneously targeted.
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PMID:Induction of interleukin-8 preserves the angiogenic response in HIF-1alpha-deficient colon cancer cells. 1614 72

Intestinal epithelial cells not only present a physical barrier to bacteria but also participate actively in immune and inflammatory responses. The migration of epithelial cells from the crypt base to the surface is accompanied by a cellular differentiation that leads to important morphological and functional changes. It has been reported that the differentiation of colonic epithelial cells is associated with reduced interleukin (IL)-8 responses to IL-1beta. Although toll-like receptor 4 (TLR4) has been previously identified to be an important component of mucosal immunity to lipopolysaccharide (LPS) in the colon, little is known about the regulation of TLR4 in colonic epithelial cells during cellular differentiation. We investigated the effects of differentiation on LPS-induced IL-8 secretion and on the expression of TLR4. Differentiation was induced in colon cancer cell line HT-29 cells by butyrate treatment or by post-confluence culture and assessed by measuring alkaline phosphatase (AP) activity. IL-8 secretion was measured by ELISA, and TLR4 protein and mRNA expressions were followed by Western blot and RT-PCR, respectively. HT-29 cells were found to be dose-dependently responsive to LPS. AP activity increased in HT-29 cells by differentiation induced by treatment with butyrate or post-confluence culture. We found that IL-8 secretion induced by LPS was strongly attenuated in differentiated cells versus undifferentiated cells, and that cellular differentiation also attenuated TLR4 mRNA and protein expressions. Pretreating HT-29 cells with tumor necrosis factor (TNF)-alpha or interferon (INF)-gamma augmented LPS-induced IL-8 secretion and TLR4 expression. These TNF-alpha- or INF-gamma-induced augmentations of LPS response and TLR4 expression were all down-regulated by differentiation. Collectively, we conclude that cellular differentiation attenuates IL-8 secretion induced by LPS in HT-29 cells, and this attenuation is related with the down-regulation of TLR4 expression.
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PMID:Cellular differentiation-induced attenuation of LPS response in HT-29 cells is related to the down-regulation of TLR4 expression. 1620 85

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