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

Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) regulate colon cancer growth and metastasis. Previous studies utilizing antibodies against the VEGF receptor (DC101) or EGF receptor (C225) have demonstrated independently that these agents can inhibit tumour growth and induce apoptosis in colon cancer in in vivo and in vitro systems. We hypothesized that simultaneous blockade of the VEGF and EGF receptors would enhance the therapy of colon cancer in a mouse model of peritoneal carcinomatosis. Nude mice were given intraperitoneal injection of KM12L4 human colon cancer cells to generate peritoneal metastases. Mice were then randomized into one of four treatment groups: control, anti-VEGFR (DC101), anti-EGFR (C225), or DC101 and C225. Relative to the control group, treatment with DC101 or with DC101+C225 decreased tumour vascularity, growth, proliferation, formation of ascites and increased apoptosis of both tumour cells and endothelial cells. Although C225 therapy did not change any of the above parameters, C225 combined with DC101 led to a significant decrease in tumour vascularity and increases in tumour cell and endothelial cell apoptosis (vs the DC101 group). These findings suggest that DC101 inhibits angiogenesis, endothelial cell survival, and VEGF-mediated ascites formation in a murine model of colon cancer carcinomatosis. The addition of C225 to DC101 appears to lead to a further decrease in angiogenesis and ascites formation. Combination anti-VEGF and anti-EGFR therapy may represent a novel therapeutic strategy for the management of colon peritoneal carcinomatosis.
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PMID:Inhibited growth of colon cancer carcinomatosis by antibodies to vascular endothelial and epidermal growth factor receptors. 1150

Colorectal cancer is the second leading cause of cancer death in the United States. Nonsteroidal anti-inflammatory drugs including sulindac are promising chemopreventive agents for colorectal cancer. Sulindac and selective cyclooxygenase (COX)-2 inhibitors cause regression of colonic polyps in familial polyposis patients. Sulindac induces apoptotic cell death in cancer cells in vitro and in vivo. In tumor cells, activation of extracellular-regulated kinase (ERK) 1/2 results in phosphorylation of several ERK1/2 effectors, including the proapoptotic protein Bad. Phosphorylation of Ser112 by ERK1/2 inactivates Bad and protects the tumor cell from apoptosis. Sulindac metabolites and other nonsteroidal anti-inflammatory drugs selectively inhibit ERK1/2 phosphorylation in human colon cancer cells. In this study we show that epidermal growth factor (EGF) strongly induces phosphorylation of ERK1/2 and Bad in HT29 colon cancer cells. EGF-stimulated phosphorylation of ERK and Bad is blocked by pretreatment with U0126, a selective MAP kinase kinase (MKK)1/2 inhibitor. Similarly, pretreatment with sulindac sulfide blocks the ability of EGF to induce ERK1/2 and Bad phosphorylation, but also down-regulates total Bad but not ERK1/2 protein levels. The ability of sulindac to block ERK1/2 signaling by the EGF receptor may account for at least part of its potent growth-inhibitory effects against cancer cells.
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PMID:Sulindac sulfide inhibits epidermal growth factor-induced phosphorylation of extracellular-regulated kinase 1/2 and Bad in human colon cancer cells. 1256 4

Some human colon cancer cell lines (e.g., H508 cells) express M3 subtype muscarinic receptors that are activated by cholinergic agonists. The objective of the present study was to determine the cellular mechanisms underlying M3 muscarinic receptor-mediated proliferation of H508 human colon cancer cells. In H508 cells, but not in SNU-C4 cells that do not express muscarinic receptors, acetylcholine stimulated calcium-dependent phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) and p90 ribosomal S6 kinase and consequent cell proliferation. Atropine or inhibitors of MAPK phosphorylation blocked these effects. Conversely, the actions of epidermal growth factor (EGF) on H508 cells were neither calcium dependent nor mediated by cholinergic mechanisms. Both acetylcholine- and EGF-induced phosphorylation of p44/42 MAPK was abolished in the presence of EGF receptor (EGFR) inhibitors (AG1478 and PD168393). In Chinese hamster ovary cells transfected with the rat M3 muscarinic receptor, which lack EGFR, acetylcholine-induced MAPK phosphorylation was not altered in the presence of EGFR inhibitors. In H508 cells, protein kinase C inhibitors did not alter acetylcholine- or EGF-induced MAPK phosphorylation. Finally, inhibition of EGFR activation abolished acetylcholine-induced H508 cell proliferation. These data indicate that, in H508 human colon cancer cells, cholinergic ligand interaction with M3 muscarinic receptors results in transactivation of EGFR, thereby stimulating cellular proliferation.
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PMID:Transactivation of the epidermal growth factor receptor mediates cholinergic agonist-induced proliferation of H508 human colon cancer cells. 1458 69

MMP-7 is a member of the matrix metalloproteinase family and has been shown to be involved in early intestinal tumorigenesis. However, the factors which regulate MMP-7 gene transcription in the context of early colon cancer remain to be elucidated. Epidermal growth factor (EGF) and the EGF receptor have also been demonstrated to be important in the establishment of colon adenomas. We were therefore interested in addressing the question of whether MMP-7 could be regulated by EGF and in identifying the molecular mechanisms through which this process occurs. Herein, we have demonstrated that EGF enhanced the endogenous expression of MMP-7 in a number of human colon cancer cell lines. Analysis of the MMP-7 promoter sequence reveals the presence of a number of transcription factor binding sites including ETS and AP-1 sites. Results using PEA3, ETS and AP-1 artificial promoters showed that EGF enhanced PEA3 transcription factor activity by up to 70% in comparison to non-treated cell lines. Western blot analysis of nuclear extracts from EGF stimulated cells demonstrated that there was an increase in PEA3 protein when compared to non-treated cells. In addition, using a MAPK inhibitor we have shown that EGF can mediate this increase in PEA3 transcription factors via the MAPK pathway. Using EMSA analysis we also observed that the EGF stimulated increase in PEA3 transcription factors led to increased binding to specific ETS sites within the MMP-7 promoter. These data demonstrate for the first time that EGF directly enhances MMP-7 expression via the activation of PEA3 transcription factors.
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PMID:Epidermal growth factor upregulates matrix metalloproteinase-7 expression through activation of PEA3 transcription factors. 1513 1

Colorectal cancer is a leading cause of cancer-related morbidity and mortality in the United States. Curcumin, the yellow pigment in turmeric, possesses inhibitory effects on growth of a variety of tumor cells by reducing cell proliferation and inducing apoptosis. Effects of the peroxisome proliferator-activated receptor-gamma (PPARgamma) on stimulating cell differentiation and on inducing cell cycle arrest have attracted attention from the perspective of treatment and prevention of cancer. The aim of this study was to elucidate the mechanisms by which curcumin inhibits colon cancer cell growth. In the present report, we observed that curcumin, in a dose-dependent manner, inhibited the growth of Moser cells, a human colon cancer-derived cell line, and stimulated the trans-activating activity of PPARgamma. Further studies demonstrated that activation of PPARgamma was required for curcumin to inhibit Moser cell growth. Activation of PPARgamma mediated curcumin suppression of the expression of cyclin D1, a critical protein in the cell cycle, in Moser cells. In addition, curcumin blocked EGF signaling by inhibiting EGF receptor (EGFR) tyrosine phosphorylation and suppressing the gene expression of EGFR mediated by activation of PPARgamma. In addition to curcumin reduction of the level of phosphorylated PPARgamma, inhibition of cyclin D1 expression played a major and significant role in curcumin stimulation of PPARgamma activity in Moser cells. Taken together, our results demonstrated for the first time that curcumin activation of PPARgamma inhibited Moser cell growth and mediated the suppression of the gene expression of cyclin D1 and EGFR. These results provided a novel insight into the roles and mechanisms of curcumin in inhibition of colon cancer cell growth and potential therapeutic strategies for treatment of colon cancer.
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PMID:Activation of PPAR{gamma} by curcumin inhibits Moser cell growth and mediates suppression of gene expression of cyclin D1 and EGFR. 1548 48

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

We studied growth factors and their receptors in tumor cells and tumor-associated endothelial cells as the therapeutic targets in colon cancer. Immunohistochemical analysis of 13 surgical specimens of human colon adenocarcinoma revealed that both tumor cells and tumor-associated endothelial cells in 11 of the 13 specimens expressed the epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), EGF receptor (EGFR), phosphorylated EGFR (pEGFR), vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR), and phosphorylated VEGFR (pVEGFR). HT29 human colon cancer cells growing orthotopically in the cecum of nude mice expressed a high level of EGF, EGFR, pEGFR, VEGF, VEGFR, and pVEGFR. Double-immunofluorescence staining found that tumor-associated mouse endothelial cells also expressed pEGFR and pVEGFR. Tumors in mice treated for 5 weeks with oral AEE788 (an inhibitor of EGFR and VEGFR tyrosine kinase) as a single agent or with CPT-11 alone were smaller (>50%) than those in control mice. Mice treated with the combination of AEE788 and CPT-11 had significantly smaller tumors (P < 0.01) and complete inhibition of lymph node metastasis. AEE788 alone or in combination with CPT-11 inhibited pEGFR, pVEGFR, and phosphorylated Akt expression on tumor-associated endothelial cells as well as on tumor cells. The combination therapy also significantly decreased microvessel density and tumor cell proliferation and increased the level of apoptosis in both tumor cells and tumor-associated endothelial cells. Collectively, these data suggest that the dual inhibition of EGFR and VEGFR signaling pathways in tumor cells and tumor-associated endothelial cells in combination with chemotherapy can provide a new approach to the treatment of colon cancer.
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PMID:Dual inhibition of epidermal growth factor receptor and vascular endothelial growth factor receptor phosphorylation by AEE788 reduces growth and metastasis of human colon carcinoma in an orthotopic nude mouse model. 1586 67

Interferon-alpha (IFNalpha) treatment is associated with up-regulation of epidermal growth factor receptor (HER1/EGFR) expression and marked growth inhibition while maintaining the sensitivity of the target colon cancer cells to epidermal growth factor (Gut 2004;53:123). We aimed to determine the effect of combining IFNalpha and Erlotinib (an HER1/EGFR inhibitor) on colon cancer cell line growth. Crystal-violet staining and flow cytometry were used to assess cell proliferation and expression of HER1/EGFR. IFNalpha pre-treatment followed by a combination of IFNalpha plus Erlotinib significantly enhanced the sensitivity of 7/9 of colon cancer cell lines by 7-43%. This approach may have clinical implications for improving treatment based on targeting of HER1/EGFR.
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PMID:Interferon-alpha promotes the anti-proliferative effect of Erlotinib (OSI-774) on human colon cancer cell lines. 1592 58

WNT, FGF and Hedgehog signaling pathways network together during embryogenesis, tissue regeneration, and carcinogenesis. FGF16, FGF18, and FGF20 genes are targets of WNT-mediated TCF/LEF-beta-catenin-BCL9/BCL9L-PYGO transcriptional complex. SPROUTY (SPRY) and SPRED family genes encode inhibitors for receptor tyrosine kinase signaling cascades, such as those of FGF receptor family members and EGF receptor family members. Here, transcriptional regulation of SPRY1, SPRY2, SPRY3, SPRY4, SPRED1, SPRED2, and SPRED3 genes by WNT/beta-catenin signaling cascade was investigated by using bioinformatics and human intelligence (humint). Because double TCF/LEF-binding sites were identified within the 5'-promoter region of human SPRY4 gene, comparative genomics analyses on SPRY4 orthologs were further performed. SPRY4-FGF1 locus at human chromosome 5q31.3 and FGF2-NUDT6-SPATA5-SPRY1 locus at human chromosome 4q27-q28.1 were paralogous regions within the human genome. Chimpanzee SPRY4 gene was identified within NW_107083.1 genome sequence. Human, chimpanzee, rat and mouse SPRY4 orthologs, consisting of three exons, were well conserved. SPRY4 gene was identified as the evolutionarily conserved target of WNT/beta-catenin signaling pathway based on the conservation of double TCF/LEF-binding sites within 5'-promoter region of mammalian SPRY4 orthologs. Human SPRY4 mRNA was expressed in embryonic stem (ES) cells, brain, pancreatic islet, colon cancer, head and neck tumor, melanoma, and pancreatic cancer. WNT signaling activation in progenitor cells leads to the growth regulation of progenitor cells themselves through SPRY4 induction, and also to the growth stimulation of proliferating cells through FGF secretion. Epigenetic silencing and loss-of-function mutations of SPRY4 gene in progenitor cells could lead to carcinogenesis. SPRY4 is the pharmacogenomics target in the fields of oncology and regenerative medicine.
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PMID:FGF signaling inhibitor, SPRY4, is evolutionarily conserved target of WNT signaling pathway in progenitor cells. 1646 3

Neurotensin (NT) is a highly expressed gastrointestinal (GI) neuropeptide, which modulates GI motility, secretion and cell growth as well as intestinal inflammation. Since EGF receptor is highly expressed in human colon cancer cells, we sought to examine whether NT stimulation contributes to the EGFR overexpression using nontransformed colonocyte NCM460 cells. The results show that NT treatment caused a significant increase in EGFR protein expression and gene transcription. Pretreatment with MAP kinase pathway inhibitor PD98059 blocked NT-induced EGFR expression. As the EGFR promoter has a functional Egr-1 site, previously shown to mediate its transcription in response to hypoxia, we examined the role of Egr-1 in the NT response. We first show that NT stimulated Egr-1 expression, which can be inhibited by PD98059. We also determined whether NT increases Egr-1 binding to its site within the EGFR promoter. The data indicate that NT enhanced the amount of Egr-1 binding to the EGFR Egr-1 site and that this binding was significantly decreased by PD98059. To verify that Egr-1 mediated NT-induced EGFR transcription, Egr-1 siRNA was used to knock down its expression. The data show that transfection of Egr-1 siRNA significantly inhibited NT-stimulated EGFR transcription. Together, our results suggest that NT can stimulate MAP kinase-mediated Egr-1 and EGFR gene expression in human colonocytes. Our results may be relevant to the mechanisms by which NT participates in the development of colon cancer.
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PMID:Neurotensin stimulates expression of early growth response gene-1 and EGF receptor through MAP kinase activation in human colonic epithelial cells. 1723 May 32


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