Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

PDGF-B released from colon tumor cells regulated tumor growth in athymic mice in a paracrine manner by inducing blood vessel formation. A positive correlation was found between expression of PDGF B-chain in cells grown in vitro and the number of factor VIII-positive blood vessels in tumors induced by three classes of colon carcinoma cell lines. Elevated expression of PDGF-B was also correlated with tumor size. Each cell line had the same mutations in the colon cancer genes APC, DCC, and p53 and had wild type c-K-ras genes (Huang et al. [1994] Oncogene, 9:3701-3706.) eliminating the possibility that any differences in tumor blood vessel formation were due to mutations and/or deletions in these genes. Colon carcinoma cells released biologically active PDGF capable of stimulating the growth of NIH3T3 cells, which was inhibited by neutralizing antisera to PDGF-AB chains. An inverse correlation was found between induction of factor VIII-positive blood vessels and expression of vascular endothelial growth factor (VEGF), while no correlation was seen with expression of either TGF alpha or k-FGF. Basic fibroblast growth factor (FGF) expression was not detected in these tumor cells. TGF beta 1 was capable of inducing PDGF-B expression in the undifferentiated U9 colon carcinoma cell line, but this sensitivity was not seen in differentiated cells. In contrast, TGF beta 1 inhibited VEGF expression in both undifferentiated cells and differentiated colon cancer cells. Thus, TGF beta 1 has two roles in the growth of undifferentiated U9 colon carcinoma cells in vivo: direct stimulation of cell proliferation as we have showed in earlier studies, and an increase in angiogenesis by inducing PDGF-B.
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PMID:Platelet-derived growth factor-B increases colon cancer cell growth in vivo by a paracrine effect. 759 1

We studied the correlation between expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors with vascularity, metastasis, and proliferative index of human colon cancers. Immunohistochemical analyses using antibodies against VEGF, bFGF, their receptors (KDR, flt-1, bek, and flg), factor VIII, and proliferating cell nuclear antigen were carried out on archival specimens of 52 human colon carcinomas and 10 adenomas. Vessels were quantitated by light microscopy (x200), and the intensity of staining for VEGF and bFGF was assessed on a scale of 0-3+. The presence or absence of immunostaining for KDR, flt-1, bek, and flg was evaluated in endothelial cells, and proliferation was determined by counting the number of proliferating cell nuclear antigen-positive cells per 500 tumor cells. Expression of VEGF and KDR was higher in metastatic than in nonmetastatic neoplasms and directly correlated with the extent of neovascularization and the degree of proliferation, whereas expression of bFGF, flt-1, bek, and flg did not differ among tumor types. Vessel counts were greater in metastatic tumors than in nonmetastatic tumors. These findings support the hypothesis that VEGF is an important angiogenic factor in primary and metastatic human colon cancer. VEGF expression and vessel counts may aid in predicting patients at risk for metastasis from colon cancer.
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PMID:Expression of vascular endothelial growth factor and its receptor, KDR, correlates with vascularity, metastasis, and proliferation of human colon cancer. 766 63

To determine the effect of cell density on vascular endothelial growth factor (VEGF) expression and the mechanism of this effect, four human colon cancer cell lines were grown as sparse or confluent monolayers or as spheroids. VEGF mRNA increased > 2-fold in cells grown as confluent monolayers or spheroids compared with cells grown as sparse monolayers. Semiquantitative reverse transcription-PCR demonstrated a 2-fold increase in the larger VEGF mRNA isoform (189 bp) in confluent cells. Sparse cells grown in conditioned medium from confluent cells demonstrated a > 2-fold increase in VEGF mRNA. These data suggest that VEGF expression may be regulated by an unidentified soluble factor.
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PMID:Regulation of vascular endothelial growth factor expression in human colon carcinoma cells by cell density. 875 53

An increased expression of nitric oxide synthase (NOS) has been observed in human colon carcinoma cell lines as well as in human gynecological, breast, and central nervous system tumors. This observation suggests a pathobiological role of tumor-associated NO production. Hence, we investigated NOS expression in human colon cancer in respect to tumor staging, NOS-expressing cell type(s), nitrotyrosine formation, inflammation, and vascular endothelial growth factor expression. Ca2+-dependent NOS activity was found in normal colon and in tumors but was significantly decreased in adenomas (P < 0.001) and carcinomas (Dukes' stages A-D: P < 0.002). Ca2+-independent NOS activity, indicating inducible NOS (NOS2), is markedly expressed in approximately 60% of human colon adenomas (P < 0.001 versus normal tissues) and in 20-25% of colon carcinomas (P < 0.01 versus normal tissues). Only low levels were found in the surrounding normal tissue. NOS2 activity decreased with increasing tumor stage (Dukes' A-D) and was lowest in colon metastases to liver and lung. NOS2 was detected in tissue mononuclear cells (TMCs), endothelium, and tumor epithelium. There was a statistically significant correlation between NOS2 enzymatic activity and the level of NOS2 protein detected by immunohistochemistry (P < 0.01). Western blot analysis of tumor extracts with Ca2+-independent NOS activity showed up to three distinct NOS2 protein bands at Mr 125,000-Mr 138,000. The same protein bands were heavily tyrosine-phosphorylated in some tumor tissues. TMCs, but not the tumor epithelium, were immunopositive using a polyclonal anti-nitrotyrosine antibody. However, only a subset of the NOS2-expressing TMCs stained positively for 3-nitrotyrosine, which is a marker for peroxynitrite formation. Furthermore, vascular endothelial growth factor expression was detected in adenomas expressing NOS2. These data are consistent with the hypothesis that excessive NO production by NOS2 may contribute to the pathogenesis of colon cancer progression at the transition of colon adenoma to carcinoma in situ.
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PMID:Frequent nitric oxide synthase-2 expression in human colon adenomas: implication for tumor angiogenesis and colon cancer progression. 944 14

We previously demonstrated an association between vascular endothelial growth factor (VEGF), vessel counts and metastasis in human colon cancer specimens. Mutant p53 has been implicated in the regulation of angiogenesis. Immuno-histochemical detection of p53 protein has been associated with p53 gene mutations. We sought to determine a correlation between p53 protein detection (i.e., mutant p53), VEGF expression and vessel counts in human colon cancer. Surgical specimens from 93 patients with colon cancer were stained immuno-histochemically for p53, VEGF and factor VIII. Vessel counts were greater in metastatic tumors than in nonmetastatic tumors and adenomas, and greater in nonmetastatic tumors than in adenomas. Vessel counts were highest in tumors with the highest VEGF expression. Vessel counts and VEGF expression were greater in p53-positive tumors than in p53-negative tumors. p53 expression correlated with both VEGF expression and vessel count. The association of p53 expression with VEGF and vessel count suggests that the poor prognosis associated with p53 mutations may be due, in part, to the role of mutant p53 in promoting angiogenesis.
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PMID:p53, vessel count, and vascular endothelial growth factor expression in human colon cancer. 949 55

We have previously shown that platelet-derived endothelial cell growth factor (PD-ECGF) is associated with angiogenesis of human colon cancer; this factor is expressed at high levels in vascular tumors that express low levels of vascular endothelial growth factor (VEGF). In these colon cancers, the major source of PD-ECGF is the infiltrating cells. In this study, we examined the role of PD-ECGF in the angiogenesis of human gastric cancer. Immunostaining for PD-ECGF was done on 93 gastric cancers previously stained for VEGF, basic fibroblast growth factor, and factor VIII-related antigen (specific for endothelial cells). To determine the cell type expressing PD-ECGF, double staining was done using antibodies to both PD-ECGF and CD68 (specific for macrophages). PD-ECGF was expressed more frequently in infiltrating cells (positive CD68 staining; 53.8%) than in tumor epithelium (9.7%; P < 0.0001). Infiltrating cells simultaneously stained positive for both PD-ECGF and CD68. An association between PD-ECGF expression in infiltrating cells, VEGF expression in tumor epithelium, and vessel count was observed in intestinal-type gastric cancer but not in diffuse-type gastric cancer. Vessel count was greater in tumors with high expression of both PD-ECGF and VEGF than in those with high expression of either factor alone (P = 0.002). Multiple angiogenic factors expressed by both tumor cells and infiltrating cells may play a role in the regulation of angiogenesis in intestinal-type gastric cancer.
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PMID:Significance of platelet-derived endothelial cell growth factor in the angiogenesis of human gastric cancer. 951 32

Recent studies have indicated that angiogenesis may be regulated, in part, by p53 tumor suppressor gene function. We hypothesized that wild-type p53 replacement would down-regulate vascular endothelial growth factor (VEGF) expression and inhibit angiogenesis. KM12L4 and SW620, human colon cancer cell lines with p53 mutations, were transduced with a replication-defective adenoviral vector containing the wild-type p53 gene (Ad5/CMV/p53). Reverse transcription-PCR confirmed the presence of p53 in Ad5/CMV/p53-transduced cells. Transduction of colon cancer cells with wild-type p53 decreased VEGF RNA expression compared with that of controls. The decrease in VEGF expression in SW620 cells was dose dependent, with a 49% decrease observed at a multiplicity of infection of 50, and a 71% decrease observed at a multiplicity of infection of 100. Similar effects were seen in KM12L4 cells. VEGF supernatant protein levels were significantly reduced compared with those in nontransduced controls 48 h after the introduction of wild-type p53. Ad5/CMV/p53 inhibited tumor cell-induced angiogenesis in vivo. Restoration of wild-type p53 expression may decrease tumor growth by inhibiting the angiogenic response. These findings may explain, in part, the bystander effect seen with p53 tumor suppressor gene therapy.
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PMID:Adenovirus-mediated wild-type p53 gene transfer down-regulates vascular endothelial growth factor expression and inhibits angiogenesis in human colon cancer. 962 60

Although some studies have shown that overexpression of vascular endothelial growth factor (VEGF) mRNA or protein is correlated with the progression of human malignancies, it is still unknown whether the VEGF level in tumor tissue correlates with tumor growth or metastasis. The present clinical study enrolled 26 patients with colon cancer and revealed that the VEGF level in tumor tissue was significantly higher than in adjacent normal tissue (220.93 +/- 217.64 pg/mg protein in the tumor tissue; n = 26; 38.93 +/- 20.26 in the normal tissue; n = 26) and significantly correlated with tumor size, whereas it did not correlate with other clinicopathological variables. The animal study involved orthotopic transplantation of a human colon cancer strain into nude mice and demonstrated that the VEGF level of transplanted tumor tissue (2,318.5 +/- 1,340.9 pg/mg protein) was significantly correlated with tumor weight (1,856.4 +/- 928.9 mg), but not with the number of the liver metastatic foci. These results indicate that VEGF produced by primary tumors of colon cancers may mainly promote primary tumor growth.
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PMID:Quantitative analysis of vascular endothelial growth factor in colon cancer. Clinical and experimental. 970 54

We investigated the role of insulin-like growth factor (IGF)-I and IGF-binding proteins (IGFBPs) in the regulation of vascular endothelial growth factor (VEGF) expression in colon cancer cells and the mechanism by which this regulation occurs. HT29 human colon cancer cells were treated with IGF-I for various time periods. VEGF mRNA expression increased within 2 h and peaked at 24 h. SW620 colon cancer cells exhibited a peak induction of VEGF mRNA 8 h after IGF-I treatment. IGF-I induction of VEGF was confirmed at the protein level. In experiments using transient transfection of VEGF promoter-reporter constructs into HT29 cells, IGF-I increased the activity of the VEGF promoter, and pretreatment of HT29 cells with dactinomycin abrogated the induction of VEGF mRNA by IGF-I. The half-life of VEGF mRNA was not prolonged by treatment with IGF-I. Blocking the activity of IGFBP-4 did not significantly modulate the effect of IGF-I induction of VEGF mRNA in HT29 cells. Treating cells with des-(1-3)-IGF-I (an active derivative of IGF-I that does not bind to binding proteins) had effects on VEGF mRNA expression that were similar to those of IGF-I. These findings suggest that IGF-I regulates VEGF expression in human colon cancer cells by induction of transcription of the VEGF gene. IGFBPs do not significantly affect IGF-I induction of VEGF.
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PMID:Regulation of vascular endothelial growth factor expression in human colon cancer by insulin-like growth factor-I. 973 15

Hypoxia regulates the expression of both vascular endothelial growth factor (VEGF) and its receptor (KDR). We have shown that cell density regulates VEGF expression in colon cancer and hypothesized that a similar mechanism regulates KDR in endothelial cells. Human umbilical vein endothelial cells were grown as sparse and confluent monolayers. Northern blot analysis revealed that KDR and VEGF mRNA expression in confluent cells was more than two-fold greater than in sparse cells. In contrast, flt-1 expression increased only slightly in cells grown to confluence. Cells were then plated at various concentrations and subjected to semi-quantitative PCR; KDR mRNA expression increased as cell density increased. Serum-free conditioned medium from cells grown to confluency for 48 h was added to sparsely plated cells, and KDR expression in the sparse cells increased twofold. We conclude that cell density regulates KDR endothelial cell expression via an unidentified soluble factor.
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PMID:Regulation of vascular endothelial growth factor receptor KDR in vitro by a soluble factor in confluent endothelial cells. 973 40


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