Biomedical subjects

M P Moyer

Publications and source records attributed to M P Moyer.

At least 19 recordsLinked to original sources

PubMed2002

Consumption of an omega-3 fatty acids product, INCELL AAFA, reduced side-effects of CPT-11 (irinotecan) in mice.

INCELL AAFA, an omega-3 polyunsaturated fatty acid product containing a high concentration of long chain fatty acids, was tested for its ability to ameliorate the harmful side effects of CPT-11 chemotherapy including: leukopenia, anaemia, asthenia, weight loss and liver involvement. Four groups of mice were fed an AIN-76 diet modified to contain: 10% w/w corn oil (CO), 0% AAFA; 9% CO, 1% AAFA; 8% CO, 2% AAFA; or 7% CO, 3% AAFA. After 2 weeks on the diets, half of the mice received CPT-11 chemotherapy (60 mg kg(-1) q 4 days, i.v.) the rest of the mice received vehicle for 2 weeks. It was found that 2% AAFA in the diet of the CPT-11 treated mice: decreased apoptotic figures in the duodenal crypts; markedly suppressed the inflammatory eicosanoid, prostaglandin E(2) in the liver; prevented liver hypertrophy; improved white blood cell counts; significantly increased red blood cell counts; decreased numbers of CPT-11 induced immature red blood cell and micronuclei in red blood cells of the peripheral blood; increased eicosapentaenoic acid and docosahexaenoic acid in liver cell membranes and maintained normal grooming behaviour. Thus 2% AAFA in the diet reduced the side effects of CPT-11 treatment in mice.

Animals↗

PubMed2001

Signal transduction pathways mediating neurotensin-stimulated interleukin-8 expression in human colonocytes.

Neurotensin (NT), a neuropeptide released in the gastrointestinal tract in response to several stimuli, is involved in the pathophysiology of colonic inflammation. However, the molecular mechanism(s) mediating this proinflammatory response remains unclear. We found that NCM460, non-transformed human colonocytes, express a functional high affinity NT receptor that mediates NT-induced Erk activation. By using NCM460 cells stably transfected with NTR1, we show that NTR1 activation leads to interleukin (IL)-8 secretion that is mediated via both NF-kappaB- and Erk-dependent pathways. In addition, NT-stimulated NF-kappaB activation is dependent on intracellular calcium release. NT-stimulated Erk activity requires Ras activation because overexpression of the dominant negative Ras mutant Ras-17N almost completely inhibits the Erk activation. Furthermore, NT directly stimulates Ras-GTP formation as shown by a Ras-GTP pull-down assay. By using reporter gene constructs containing targeted substitutions in the IL-8 promoter, we show that the NF-kappaB, AP-1, and to a lesser degree the C/EBP sites in the IL-8 promoter region are required for IL-8 gene expression induced by NT. In summary, our results demonstrate that NT stimulates calcium-dependent NF-kappaB and Ras-dependent Erk pathways that mediate the release of IL-8 from non-transformed human colonocytes. We speculate that these NT-related proinflammatory pathways are important in the pathophysiology of colonic inflammation.

Calcium↗

PubMed2001

Transdifferentiation of human islet cells in a long-term culture.

It has been established that ductal cells or precursor cells within the ductal tree of the pancreas can differentiate into islet cells. Although islet cells can also form exocrine cells, it is unclear whether they arise from precursor (stem) cells or from mature endocrine cells by transdifferentiation. Using a defined culture medium and technique for islet purification, for the first time we were able to maintain human islets in culture for more than a year. Multilabeling immunohistochemical and immunoelectron microscopic examination of the islets at different days of culture using islet cell markers (antibodies to hormones, neuron-specific enolase, chromogranin A) and ductal cell markers (cytokeratins 7 and 19, carbonic anhydrase II, DU-PAN2, CA 19-9, and MUC1) revealed that endocrine cells gradually transdifferentiate to ductal, acinar, and intermediary cells. Although islet hormone secretion ceased after day 28 in culture, endocrine cells were still detectable at day 60. However, later, all endocrine and exocrine cells were replaced by undifferentiated cells that expressed neuron-specific enolase, chromogranin A, laminin, vimentin, cytokeratin 7 and 19, alpha-1-antitrypsin, transforming growth factor-alpha, and epidermal growth factor receptor. Our data thus show that, under proper conditions, human islets can be maintained in vitro over a long period and that, in the culture condition, islet cells seem to transdifferentiate to exocrine cells and undifferentiated cells, which may be considered pancreatic precursor (stem) cells.

Biomarkers↗

PubMed2001

Mechanism of thiamine uptake by human colonocytes: studies with cultured colonic epithelial cell line NCM460.

Thiamine (vitamin B(1)) is essential for normal cellular functions and growth. Mammals cannot synthesize thiamine and thus must obtain the vitamin via intestinal absorption. The intestine is exposed to a dietary thiamine source and a bacterial source in which the vitamin is synthesized by the normal microflora of the large intestine. Very little is known about thiamine uptake in the large intestine. The aim of this study was, therefore, to address this issue. Our results with human-derived colonic epithelial NCM460 cells as a model system showed thiamine uptake to be 1) temperature- and energy dependent, 2) Na(+) independent, 3) increased with increasing buffer pH from 5 to 8 and after cell acidification but inhibited by amiloride, 4) saturable as a function of concentration, 5) inhibited by thiamine structural analogs but not by unrelated organic cations, and 6) inhibited by modulators of a Ca(2+)/calmodulin-mediated pathway. NCM460 cells and native human colonic mucosa expressed the recently cloned human thiamine transporter THTR-1 (product of the SLC19A2 gene) at both mRNA and protein levels. These results demonstrate for the first time that human NCM460 colonocytes possess a specific carrier-mediated system for thiamine uptake that appears to be under the regulation of an intracellular Ca(2+)/calmodulin-mediated pathway. It is suggested that bacterially synthesized thiamine in the large intestine may contribute to thiamine nutrition of the host, especially toward cellular nutrition of the local colonocytes.

Carrier Proteins↗

PubMed2000

Seven genes that are differentially transcribed in colorectal tumor cell lines.

To identify genes which are differentially transcribed in colorectal tumor cells, we compared the two human tumor cell lines, SW480 and HCT116, with the cell line, NCM460, from normal colon epithelium as a control. Using the methods of differential display reverse transcription PCR and Northern blot hybridization, we detected the differential transcription of seven genes: cholecystokinin, reticulocalbin, Rab5 guanine nucleotide exchange factor Rabex5, caldesmon, differentiation related gene 1 (drg1), taxol resistant associated gene 3 (Trag-3) and the gene for the placental protein, diff33. The yet unidentified cDNA of the human Rabex5 gene and the 3' untranslated region of the human caldesmon gene were cloned.

Amino Acid Sequence↗

PubMed2000

Dietary fish oil sensitizes A549 lung xenografts to doxorubicin chemotherapy.

A549 xenografts were allowed to grow in nude mice to about 5 mm in diameter, then diets were changed to modified AIN-76 diets containing 19% wt./wt. fish oil (FO) or 20% wt./wt. corn oil (CO). Ten days later dietary ferric citrate (0.3% wt./dry wt.) was added and doxoribicin (DOX) treatment (3.6 mg/kg i.v. each of the 5 days for 18 days) commenced. Treatment with DOX halted the growth of tumors in the CO fed mice. However, in those mice, which consumed FO or FO with ferric citrate, treatment with DOX caused significant tumor regression.

Analysis of Variance↗

PubMed2000

Connexin-independent ganciclovir-mediated killing conferred on bystander effect-resistant cell lines by a herpes simplex virus-thymidine kinase-expressing colon cell line.

A novel gap junction-independent mechanism for ganciclovir-mediated bystander effect killing by a herpes simplex virus thymidine kinase (HSV-TK)-expressing SW620 human colon tumor cell line has been characterized. The mechanism of the HSV-TK/GCV bystander effect for many tumor cell lines has been demonstrated to be due to connexin gap junction transfer of phosphorylated ganciclovir (GCV) metabolites; however, there may be as yet uncharacterized connexin-independent mechanisms for the effect. To address this, the bystander effect was further evaluated in a panel of cell lines mixed with homologous HSV-TK-expressing cell lines, a SW620.TK cell line, or a high connexin43-expressing PA-317.TK cell line. Of the 10 cell lines tested, 4 were found to be resistant to bystander effect killing by their homologous HSV-TK-expressing cell lines and the PA-317.TK cells, but all of the cell lines were sensitive to GCV killing when mixed with the SW620.TK cells. The SW620.TK cells were then further evaluated for any indication of extracellular GCV metabolite efflux. Culture medium from SW620.TK cells labeled with [(3)H]GCV was evaluated for the presence of GCV nucleotides by ion-exchange column separation and HPLC analysis. The presence of GCV mono-, di-, and triphosphate metabolites in the medium was detected. Inclusion in the medium of inhibitors of extracellular phosphatases and ecto-ATPases increased the proportion of GCV metabolites recovered. These results indicate that phosphorylated GCV metabolites can be effluxed from SW620.TK cells and that some type of cellular uptake mechanism independent of gap junctions exists for nucleotide entry into neighboring cells.

Cell Count↗

PubMed2000

Two-drug combinations that increase apoptosis and modulate bak and bcl-X(L) expression in human colon tumor cell lines transduced with herpes simplex virus thymidine kinase.

Herpes simplex virus thymidine kinase (HSV-TK) and ganciclovir (GCV) gene therapy can induce apoptosis in tumor cells that are normally resistant to this type of cell death, although the cellular mechanisms by which this occurs remain to be elucidated. Human colon tumor cell lines expressing HSV-TK were treated with GCV or four other inducers of apoptosis: butyrate, camptothecin (CPT), Taxol (paclitaxel), or 7-hydroxystaurosporine (UCN-01). Over a 2-4 day treatment period with GCV or the other four drugs, protein levels of the apoptosis agonist Bak increased 1.5- to 3-fold, whereas a corresponding decrease in the levels of the apoptosis antagonist, Bcl-X(L), was observed in butyrate-, CPT-, and 7-hydroxystaurosporine (UCN-01)-treated cells. GCV and paclitaxel treatments resulted in increased levels of Bcl-X(L). In two-drug combinations with GCV plus one of the four other drugs, increased tumor cell killing was found with GCV plus UCN-01 or with some GCV/butyrate combinations; the other two tested combinations were largely antagonistic. The GCV/UCN-01 and GCV/butyrate combinations resulted in increased Bak and decreased Bcl-X(L) protein levels, while the GCV/CPT and GCV/paclitaxel combinations resulted in increased levels of both proteins. The results highlight the potential for new combination therapies of HSV-TK/GCV and chemotherapeutic drugs that result in increased tumor cell apoptosis for future treatments of colon cancer.

Alkaloids↗

PubMed2000

Maintenance of human islets in long-term culture.

The long-term maintenance of human islets in culture has remained a challenge. Despite advancements in culture techniques, human islets proved to have a short life span in vitro. For the first time, we have succeeded in maintaining human islets in a defined culture medium for more than 12 months. Freshly isolated islets from a 38-year-old donor were cultured in M3:5 medium and placed on a rocker for 14 days to remove contaminated exocrine and mesenchymal cells which attached to the bottom. The floating islets were purified by daily hand-picking and transfer into fresh medium. After 14 days, purified islets were allowed to attach to the bottom of the flasks and to expand. At various time points, islets were examined immunohistochemically and electron microscopically, and the secretion of islet hormones and their mRNA were determined by radioimmunoassay and reverse transcriptase polymerase chain reaction, respectively. Within seven days of culture, ductular and acinar cells developed within the initially normal islets. With time, exocrine cell types expanded while the number of the endocrine cells and their secretion decreased. At day 60, only a few endocrine cells were identifiable, whereas most of the cells appeared undifferentiated and expressed cytokeratin 7 and 19, neuron specific enolase, tomato lectin, phaseolus leucoagglutinin, laminin, and vimentin. After 60 days, the culture consisted entirely of undifferentiated cells which could be maintained in culture for 270 days before they became senescent. This is the first report on the long-term maintenance of human islet cells in culture and allows an insight into the complex process of endocrine cell differentiation.

Adult↗

PubMed2000

Establishment of a human polyclonal oral epithelial cell line.

OBJECTIVE: To develop a human oral epithelial cell line to constitute a continuous source of cells readily available for human oral epithelial cell research. STUDY DESIGN: Oral epithelial cells from a 30-week gestational, stillborn male fetus were grown in serum-free medium and transfected by lipid-mediation with the shuttle vector plasmid, pZ189, containing the T-antigen coding region and replication origin from the SV40 virus. RESULTS: Resulting cultures produced foci of rapidly multiplying cells that failed to senesce, in contrast to controls. The transformed culture, designated GMSM-K, was polyclonal. The original culture possessed a normal human male karyotype, and the transformed line was largely hypotetraploid. Multiple clones, isolated from soft agar studies and low density plating, showed decreased doubling times. Electron microscopy and immunohistochemistry confirmed an epithelial phenotype. Cells did not generate tumors in nude mice. CONCLUSION: Few human epithelial cell lines are available to investigators and most are tumor-derived. The nontumor-derived GMSM-K line has value as a resource for human oral epithelial cell research.

Animals↗

PubMed2000

Differentiation of islet cells in long-term culture.

Our previous studies in the hamster pancreatic cancer model have shown that exocrine pancreatic cancer arises from ductal/ductular cells, as well as from within the islets, most probably from islet precursor (stem) cells. To identify and characterize these cells, we established a long-term culture from isolated hamster islets and investigated their growth, differentiation, and expression of biomarkers. Islets maintained their original form and structure within the first 14 days in culture. However, beginning at day 7, ductular structures began to form within the islets. At day 21 in culture, acinar cells, intermediary cells, oncocytes, and cells comparable to pancreatic hepatocytes also appeared between ductular and endocrine cells. The number of duct-like cells gradually increased, whereas the number of hormone-producing cells decreased. After 35 days in culture, the exocrine cells disappeared, and undifferentiated cells formed a monolayer. These cells expressed cytokeratins, alpha1-antitrypsin, transforming growth factor-alpha, epidermal growth factor receptor, carbonic anhydrase II, vimentin, laminin, and showed binding to tomato lectin and Phaseolus vulgaris leukoagglutinin. They did not express the regulatory transcriptional factors, insulin-promoting factor 1, NKx6.1, Pax6, and NeuroD. The results thus indicate that islet cells have potential to form exocrine cells. At present, it is not clear whether these cells originate from preexisting stem cells or from transdifferentiated islet cells.

Animals↗

PubMed2000

Establishment of human pancreatic ductal cells in a long-term culture.

Cultivation and preservation of human pancreatic ductal cells have remained a challenge. With a defined culture medium and refinement of culturing techniques, we have been able to maintain human pancreatic ductal cells without any genetic manipulation in culture for more than 16 months. Freshly isolated ductal fragments were placed on a rocker in M3:5 medium free of collagen for 14 days to remove fibroblasts and endocrine cells before allowing them to attach. The cells produced an excessive amount of mucin and expressed the duct specific cytokeratins (CK) 7 and 19, DU-PAN2, CA19-9, carbonic anhydrase II (CA II), and secretin receptors. During the course of the culture, however, the cells gradually lost the expression of CA II, secretin receptors, DU-PAN2, and CA 19-9 and assumed an undifferentiated phenotype, which showed an upregulation of transforming growth factor alpha (TGFalpha) and epidermal growth factor receptor (EGFR), an increase in the expression of Ki-67, and an increased binding to Phaseolus vulgaris leucoagglutinin (PHA-L) and tomato lectin. These ductal cells present a useful source with which to study physiologic aspects of ductal cells including differentiation.

Adult↗

PubMed2000

Riboflavin uptake by human-derived colonic epithelial NCM460 cells.

Normal microflora of the large intestine synthesize a number of water-soluble vitamins including riboflavin (RF). Recent studies have shown that colonic epithelial cells possess an efficient carrier-mediated mechanism for absorbing some of these micronutrients. The aim of the present study was to determine whether colonic cells also possess a carrier-mediated mechanism for RF uptake and, if so, to characterize this mechanism and study its cellular regulation. Confluent monolayers of the human-derived nontransformed colonic epithelial cells NCM460 and [(3)H]RF were used in the study. Uptake of RF was found to be 1) appreciable and temperature and energy dependent; 2) Na(+) independent; 3) saturable as a function of concentration with an apparent K(m) of 0.14 microM and V(max) of 3.29 pmol x mg protein(-1) x 3 min(-1); 4) inhibited by the structural analogs lumiflavin and lumichrome (K(i) of 1.8 and 14.1 microM, respectively) but not by the unrelated biotin; 5) inhibited in a competitive manner by the membrane transport inhibitor amiloride (K(i) = 0.86 mM) but not by furosemide, DIDS, or probenecid; 6) adaptively regulated by extracellular RF levels with a significant and specific upregulation and downregulation in RF uptake in RF-deficient and oversupplemented conditions, respectively; and 7) modulated by an intracellular Ca(2+)/calmodulin-mediated pathway. These studies demonstrate for the first time the existence of a specialized carrier-mediated mechanism for RF uptake in an in vitro cellular model system of human colonocytes. This mechanism appears to be regulated by extracellular substrate level and by an intracellular Ca(2+)/calmodulin-mediated pathway. It is suggested that the identified transport system may be involved in the absorption of bacterially synthesized RF in the large intestine and that this source of RF may contribute toward RF homeostasis, especially that of colonocytes.

Biological Transport↗

PubMed2000

Effect of telomere and telomerase interactive agents on human tumor and normal cell lines.

Shortening of telomeres along with an up-regulation of telomerase is implicated in the immortality of tumor cells. Targeting either telomeres or telomerase with specific compounds has been proposed as an anticancer strategy. Because telomerase activity and telomeres are found in normal cells, telomere or telomerase targeting agents could induce side effects in normal tissues. We evaluated the effects of telomere and telomerase interactive agents in human tumor and normal cell lines to try to determine the potential side effects those agents might induce in patients. Toxicity of the G-quadruplex interactive porphyrins (TMPyP4, TMPyP2) and azidothymidine (AZT) were tested using a cell-counting technique against normal human cell lines (CRL-2115 and CRL-2120, fibroblasts; NHEK-Ad, adult keratinocytes; CCL-241, small intestinal cells; NCM 460, colonic mucosal epithelial cells) and human tumor cell lines (MDA-MB 231 and Hs 578T, breast cancer; SK-N-FI, neuroblastoma; HeLa, cervix cancer; MIA PaCa-2, pancreatic cancer; HT-29 and HCT-116, colon cancer; DU 145, prostatic cancer cell line). Telomerase activity of these cell lines was measured by a non-PCR-based conventional assay. The effects of TMPgammaP2, TMPyP4, and AZT were also evaluated against normal human bone marrow specimens, using a granulocyte-macrophage colony-forming assay (CFU-GM). AZT showed very low cytotoxic effects against normal and tumor cell lines, with the IC50 values above 200 microM. The IC50 values for TMPyP2 and TMPyP4 in normal human cell lines were in the range of 2.9-48.3 microM and 1.7-15.5 microM, respectively, whereas in tumor cell lines the IC50 values were 11.4-53 microM and 9.0-28.2 microM, respectively. Within the tissue types, keratinocytes were more sensitive to TMPyP4 than fibroblasts, and small intestinal cells were more sensitive than colonic mucosal epithelial cells. The IC50 for TMPyP2 and TMPyP4 in the normal marrow colony-forming assays were 19.3 +/- 5.1 microM and 47.9 +/-1.0 microM, respectively. In conclusion, the in vitro cytotoxicity of the telomere interactive agent TMPyP4 is comparable in human tumor and normal cell lines, which indicates that TMPyP4 could have effects on normal tissues.

Bone Marrow Cells↗

PubMed1999

Effects of smokeless tobacco and tumor promoters on cell population growth and apoptosis of B lymphocytes infected with epstein-barr virus types 1 and 2.

The effects of smokeless tobacco purified products 4-(N-methyl-N-nitrosamine)-1-3-pyridinyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN), smokeless tobacco extracts (dry snuff, moist snuff, and loose leaf), and the tumor promoters 12-O-tetradecanoyl phorbol-13-acetate (TPA) and n-butyrate on cell population growth, cell death, and apoptosis were studied in B lymphocyte cell lines harboring Epstein-Barr virus (EBV) type 1 (Raji and X50-7) or type 2 (HR-1K and AG876) and in an EBV-uninfected control lymphocyte cell line (Ramos). Spontaneous apoptosis was present in all EBV-infected cell lines, but at varying levels. Spontaneous and induced apoptosis were generally greater by Student-Newman-Keuls tests in cells harboring EBV type 2 compared to EBV type 1. The greatest effects on cell population growth, cell death, and apoptosis on cells harboring lytic EBV type 1 (X50-7) was with each of the three smokeless tobacco extracts. The greatest effects on cells harboring EBV type 2 was with TPA and n-butyrate. There were no effects of smokeless tobacco extracts on the Raji cell line that harbors EBV type 1 incapable of lytic replication. Smokeless tobacco purified products, NNN and NNK, had no discernible effects. At the concentrations used in these experiments, there appears to be an EBV type-specific response to chemical induction, with greater susceptibility of lytic EBV type 1 to smokeless tobacco extracts and lytic EBV type 2 to TPA and n-butyrate. This EBV type-specific susceptibility to the effects of smokeless tobacco extracts is another phenotypic difference between EBV types. The use of smokeless tobacco products may affect B lymphocytes infected with replication-capable EBV in the oropharynx. The absence of significant effects with NNK and NNN suggests that these properties reside with other compounds present in tobacco extracts.

Apoptosis↗

PubMed1999

Differential gene expression in colon carcinoma cells and tissues detected with a cDNA array.

Expression of selected genes coding for proteins with defined cellular functions was analysed in human cell lines derived from normal colonic mucosa, non-mucinous colonic carcinomas and mucinous colonic carcinomas. Altered expression of 10 genes in colon carcinoma cells was found by using a cDNA array; 6 of these alterations (60%) were confirmed by Northern blotting or semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Among these 6 genes, 3 transcription factors as well as the topoisomerase II alpha and the mitosis inhibitor WEE1Hu gene were significantly suppressed in the tumour cell lines. In addition, the gene coding for the cell cycle inhibitor p21 was overexpressed only in cell lines derived from mucinous carcinomas. The significant suppression of the kinase WEE1Hu gene in carcinoma cells of both phenotypes and the tendency of the mucinous phenotype to overexpress p21 protein were confirmed in human colon carcinoma tissues. Our data show that the cDNA array method permits a correct identification of changes in gene expression with a relatively high accuracy. The different expression of the p21 gene in the non-mucinous and mucinous carcinoma cells supports the hypothesis that these phenotypes may develop along different genetic pathways. The detection of WEE1Hu gene suppression in colon carcinoma cells and tissues suggests its potential role in tumourigenesis.

Adenocarcinoma, Mucinous↗

PubMed1999

Evaluation of the effect of smokeless tobacco purified products and extracts on latent Epstein-Barr virus.

Numerous chemical tumor promoters induce latent Epstein Barr virus (EBV) to active replication. The effect of smokeless tobacco purified products N-nitrosonornicotine (NNN), 4-(N-methyl-N-nitrosamine)-1-3-pyridinyl)-1-butanone (NNK), benzo(a)pyrene (BaP), and smokeless tobacco extracts (dry snuff, moist snuff, and loose leaf tobacco) was tested for induction of latent EBV in Raji cells using fluorescence-activated cell sorter flow cytometry detection of the restricted component of EBV early antigen (EA-R). Concentrations of smokeless tobacco purified products or preparations were used that have carcinogenic effects in animal cell lines. There was no discernible effect for the 6-7-day duration of treatment on viability of Raji cells, or on induction of latent EBV in Raji cells. Results were comparable using paraformaldehyde- or acetone-fixed cells. There does not appear to be an in vitro effect of smokeless tobacco constituents on EBV-infected lymphocytes that may contribute to development of oral cancers.

Benzo(a)pyrene↗

PubMed1999

Target genes of beta-catenin-T cell-factor/lymphoid-enhancer-factor signaling in human colorectal carcinomas.

Mutations in the adenomatous polyposis coli or beta-catenin gene lead to cytosolic accumulation of beta-catenin and, subsequently, to increased transcriptional activity of the beta-catenin-T cell-factor/lymphoid-enhancer-factor complex. This process seems to play an essential role in the development of most colorectal carcinomas. To identify genes activated by beta-catenin overexpression, we used colorectal cell lines for transfection with the beta-catenin gene and searched for genes differentially expressed in the transfectants. There are four genes affected by beta-catenin overexpression; three overexpressed genes code for two components of the AP-1 transcription complex, c-jun and fra-1, and for the urokinase-type plasminogen activator receptor (uPAR), whose transcription is activated by AP-1. The direct interaction of the beta-catenin-T cell-factor/lymphoid-enhancer-factor complex with the promoter region of c-jun and fra-1 was shown in a gel shift assay. The concomitant increase in beta-catenin expression and the amount of uPAR was confirmed in primary colon carcinomas and their liver metastases at both the mRNA and the protein levels. High expression of beta-catenin in transfectants, as well as in additionally analyzed colorectal cell lines, was associated with decreased expression of ZO-1, which is involved in epithelial polarization. Thus, accumulation of beta-catenin indirectly affects the expression of uPAR in vitro and in vivo. Together with the other alterations, beta-catenin accumulation may contribute to the development and progression of colon carcinoma both by dedifferentiation and through proteolytic activity.

Adenocarcinoma↗