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)

The urokinase receptor (uPAR), transcriptionally activated in several cancers, contributes to tumor progression by promoting cell migration and proteolysis, and repressing expression of this gene could be of therapeutic utility. Indeed, targeting regulatory element(s) in the promoter may represent an efficient means for reducing expression because only two alleles have to be neutralized. We previously identified the -148/-124 promoter region, bound with Sp1 and Sp3, as regulatory for uPAR expression in vitro. The purpose of this study was twofold: to determine (a) the accessibility of this region in its natural chromatin setting and (b) the efficacy of WP631, a bisintercalator favoring GC-rich DNA sequences, in repressing endogenous uPAR expression in RKO colon cancer cells. In these cells, DNaseI hypersensitivity, genomic footprinting, and chromatin immunoprecipitation experiments revealed that the -148/-124 uPAR promoter region was accessible in chromatin and bound with Sp1, thus validating it as a therapeutic target. WP631 treatment competed for transcription factor binding to this regulatory region and reduced uPAR mRNA/protein. However, a chemically related compound (WP629), with low DNA binding affinity, failed to diminish uPAR protein amount. GAPDH mRNA level was only modestly affected by WP631, arguing against the possibility that this bisanthracycline universally represses expression of GC-rich promoter-driven genes. Further, uPAR function, as assessed by migration of cells across a vitronectin-coated filter, was attenuated with WP631. Thus, we have shown that the chromatinized -148/-124 regulatory region of the uPAR promoter is accessible to small molecules and that WP631, which disrupts the interaction of DNA binding proteins with this region, diminishes uPAR expression and function.
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PMID:A bisanthracycline (WP631) represses uPAR gene expression and cell migration of RKO colon cancer cells by interfering with transcription factor binding to a chromatin-accessible -148/-124 promoter region. 1626 46

Multiple growth factor receptor pathways are deregulated in colon cancer, presenting potential targets for therapeutic intervention. In colon cancer cells, epithelial growth factor receptor activation is associated with the potential for deregulation of both angiogenesis and motility-related characteristics as cell cytoskeleton and cell-cell junction structure. Growth factor activation of receptors can result in increased cyclooxygenase-2 (COX-2) expression and consequent upregulation of prostaglandin E2; this, in turn, results in localization of urokinase proteolytic activity that promotes directional motility and invasiveness of cancer cells. Optimal therapeutic strategies to inhibit cancer cell motility, invasiveness, and angiogenesis may involve combinations of growth factor receptor inhibitors, COX-2 inhibitors, and urokinase inhibitors.
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PMID:Commentary: targeting colorectal cancer through molecular biology. 1639 29

An integrated cell cultivation and protein product separation process was developed using a new type of supermacroporous polyacrylamide gel, called cryogel (pAAm-cryogel) support matrix. Human fibrosarcoma HT1080 and human colon cancer HCT116 cell lines were used to secrete urokinase (an enzyme of immense therapeutic utility) into the culture medium. The secreted protein was isolated from the circulating medium using a chromatographic capture column. A pAAm cryogel support with covalently coupled gelatin (gelatin-pAAm cryogel) was used for the cultivation of anchorage dependent cells in the continuous cell culture mode in 5% carbon dioxide atmosphere. The cells were attached to the matrix within 4-6 h of inoculation and grew as a tissue sheet inside the cryogel matrix. Continuous urokinase secretion into the circulating medium was monitored as a parameter of growth and viability of cells inside the bioreactor. No morphological changes were observed in the cells eluted from the gelatin-cryogel support and re-cultured in T-flask. The gelatin-pAAm cryogel bioreactor was further connected to a pAAm cryogel column carrying Cu(II)-iminodiacetic acid (Cu(II)-IDA)-ligands (Cu(II)-IDA-pAAm cryogel), which had been optimized for the capture of urokinase from the conditioned medium of the cell lines. Thus an automated system was built, which integrated the features of a hollow fiber reactor with a chromatographic protein separation system. The urokinase was continuously captured by the Cu(II)-IDA-pAAm cryogel column and periodically recovered through elution cycles. The urokinase activity increased from 250 PU/mg in the culture fluid to 2,310 PU/mg after recovery from the capture column which gave about ninefold purification of the enzyme. Increased productivity was achieved by operating integrated bioreactor system continuously for 32 days under product inhibition free conditions during which no backpressure or culture contamination was observed. A total 152,600 Plough units of urokinase activity was recovered from 500 mL culture medium using 38 capture columns over a period of 32 days.
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PMID:Integrated bioprocess for the production and isolation of urokinase from animal cell culture using supermacroporous cryogel matrices. 1643 98

Colon cancer progression is associated with the activation of protein kinase C (PKC), the downregulation of functional E-cadherin and an increased expression of the serine protease urokinase (u-PA) and its receptor (u-PAR). HT29-M6 intestinal epithelial cells represent an in vitro model to study colon cancer progression. These cells are induced to scatter and to invade by phorbol esters. Using proteolytic and cell signaling inhibitors, we show that HT29-M6 cells require plasminogen for the acquisition of the scattering response to PMA. Our results indicate that, prior to inducing a state of competency for plasminogen-dependent scattering, PMA triggers an ordered succession of events where upregulation of the activity of u-PA precedes proteolysis of u-PAR and active degradation of the extracellular matrix (ECM). These events poise HT29-M6 cells to a scatter-competent state that allows the subsequent localized proteolytic activation of plasminogen to plasmin, required for the execution of scattering. Finally, we show that, in addition to its enzymatic activity directed at the degradation of ECM, plasmin generates an intracellular signal resulting in the phosphorylation of ERK 1/2. For a full motogenic activity, plasmin requires this signal since the use of a MEK inhibitor (PD98059) specifically blocks the plasmin-dependent phase of cell scattering. Our observations suggest that plasmin exerts a dual role in PMA-induced scattering of HT29-M6 cells, one directed extracellularly to promote proteolysis of the ECM and one directed to generate intracellular signaling.
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PMID:Requirement of the enzymatic and signaling activities of plasmin for phorbol-ester-induced scattering of colon cancer cells. 1663 Nov 61

The urokinase receptor [urokinase plasminogen activator receptor (u-PAR)] promotes invasion and metastasis and is associated with poor patient survival. Recently, it was shown that Src induces u-PAR gene expression via Sp1 bound to the u-PAR promoter region -152/-135. However, u-PAR is regulated by diverse promoter motifs, among them being an essential activator protein-1 (AP-1) motif at -190/-171. Moreover, an in vivo relevance of Src-induced transcriptional regulators of u-PAR-mediated invasion, in particular intravasation, and a relevance in resected patient tumors have not sufficiently been shown. The present study was conducted (a) to investigate if, in particular, AP-1-related transcriptional mediators are required for Src-induced u-PAR-gene expression, (b) to show in vivo relevance of AP-1-mediated Src-induced u-PAR gene expression for invasion/intravasation and for resected tissues from colorectal cancer patients. Src stimulation of the u-PAR promoter deleted for AP-1 region -190/-171 was reduced as compared with the wild-type promoter in cultured colon cancer cells. In gelshifts/chromatin immunoprecipitation, Src-transfected SW480 cells showed an increase of phospho-c-Jun, in addition to JunD and Fra-1, bound to region -190/-171. Src-transfected cells showed a significant increase in c-Jun phosphorylated at Ser(73) and also Ser(63), which was paralleled by increased phospho-c-jun-NH(2)-kinase. Significant decreases of invasion/in vivo intravasation (chorionallantoic membrane model) were observed in Src-overexpressing cells treated with Src inhibitors, u-PAR-small interfering RNA, and dominant negative c-Jun (TAM67). In resected tissues of 20 colorectal cancer patients, a significant correlation between Src activity, AP-1 complexes bound to u-PAR region -190/-171, and advanced pN stage were observed. These data suggest that Src-induced u-PAR gene expression and invasion/intravasation in vivo is also mediated via AP-1 region -190/-171, especially bound with c-Jun phosphorylated at Ser(73/63), and that this pathway is biologically relevant for colorectal cancer patients, suggesting therapeutic potential.
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PMID:Src induces urokinase receptor gene expression and invasion/intravasation via activator protein-1/p-c-Jun in colorectal cancer. 1751 Mar 14

We have investigated the functional expression of mu-opioid receptors (MORs) in the human colon cancer cell line, HT-29. As revealed by immunocytochemistry, immunoreactivity was present in both the cytoplasm and nuclei of the cells. Challenge with morphine for 24 h (1 nM to 1 microM) barely affected cell proliferation, while the secretion of urokinase type plasminogen activator (a protease involved in invasion/metastasis) was markedly augmented by a concentration of 0.1 microM. Human colon cancer tissue from 14 consecutively operated patients was investigated by immunohistochemistry. MORs were found in the nuclei of colonocytes and immune cells of the lamina propria in tumor-free tissue. In tumor tissue, immunoreactivity was found in the membrane and often in the nuclei of tumor cells. The current findings suggest that morphine administration could affect tumor progression by interfering with, for example, invasive properties. Our demonstration of a nuclear expression of the MORs appears to be a novel finding.
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PMID:Functional expression of mu-opioid receptors in the human colon cancer cell line, HT-29, and their localization in human colon. 1768 Mar 63

The interaction of urokinase-type plasminogen activator (uPA) and its receptor, uPAR, on cell surfaces facilitates the generation of cell-bound plasmin, thus allowing cells to establish a proteolytic front that enables their migration through protein barriers. This complex also activates cell signalling pathways that influence cell functions. Clinical studies have identified uPA as an indicator of poor overall survival in patients with colorectal cancer. In the current study, a mouse model of colon cancer, Apc(Min/+), with an additional deficiency of uPA (Apc(Min/+)/Plau-/-) was used to determine the effects of uPA on tumour initiation and growth. Utilizing this model, it was found that the number of tumours was diminished in these mice relative to Apc(Min/+) mice, which correlated with the decreased leukocyte infiltration in the tumours. However, tumour growth was not impeded in Apc(Min/+)/Plau-/- mice, and proliferation and tumour vascularization were, in fact, enhanced in Apc(Min/+)/Plau-/- mice. These latter effects are consistent with a mechanism involving up-regulation of COX-2 expression and Akt pathway activation in Apc(Min/+)/Plau-/- mice. The results from this study suggest that uPA plays dual and opposing roles in regulating lesion development: one early, during the transition from normal epithelia to dysplastic lesions, and another later during tumour growth.
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PMID:A urokinase-type plasminogen activator deficiency diminishes the frequency of intestinal adenomas in ApcMin/+ mice. 1789 85

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

We have recently reported that the acute phase protein serum amyloid A (SAA), is locally and differentially expressed in neoplastic tissues of human colon. In the present study, we demonstrate that SAA enhances the plasminogen activation (PA)-activity of HT-29 colon cancer cell line. Cell-associated PA-activity was measured following the plasminogen-dependent ability of the cells to cleave the chromogenic substrate S-2251. The SAA-enhanced PA-activity was inhibited by anti-SAA antibodies. These antibodies also decreased the basal PA-activity of HT-29 cells and neutralized their cytokines (Interleukin-1beta+Interleukin-6)-enhanced PA-activity. Using specific chromogenic substrates and the fibrin clot-lysis assay, we found that SAA enhances also the PA-activity mediated by purified urokinase- and tissue-type plasminogen activators. Together, the data indicate that SAA enhances plasminogen activation and suggest its possible role in plasmin(ogen)-mediated colon cancer progression.
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PMID:Serum amyloid A enhances plasminogen activation: implication for a role in colon cancer. 1823 45

Integrin alphaupsilonbeta6 plays a very important role in the progression of colon cancer cells and is now defined as a novel, independent prognostic indicator for aggressive colon cancer in humans. Herein, we use the RNA interfering technology to downregulate the expression of alphaupsilonbeta6 in colon cancer cells. Our data demonstrate that plasmid vector based shRNA can effectively down-regulate alphaupsilonbeta6 expression in protein and mRNA levels. Supression of integrin alphaupsilonbeta6 inhibits the phosphorylation and nonphosphorylation level of ERK1/2, the secretion of uPA, pro-MMP-9 and pro-MMP-2 in tumor conditioned medium, and more important, inhibits MAPK-dependent [(3)H] labeled collagen IV degradation via the plasminogen activation cascade. Our study demonstrates in vitro that supression of integrin alphaupsilonbeta6 inhibits extracellular matrix degradation through the MAPK pathway.
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PMID:Suppression of integrin alphaupsilonbeta6 by RNA interference in colon cancer cells inhibits extracellular matrix degradation through the MAPK pathway. 1856 96


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