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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

E-cadherin is a calcium dependent cell-cell adhesion molecule. In cancer tissue, detachment of the adhesion system is indispensable for invasion and metastasis of cancer cells. We have investigated mechanism of the dysfunction of E-cadherin-dependent cell-cell adhesion system in gastric carcinoma cells. Although the high expression of E-cadherin in a scirrhous gastric cancer cell line HSC-39, the function of E-cadherin was completely abolished. Western blotting of beta-catenin in HSC-39 cells demonstrated that a truncated beta-catenin was detected. The truncation was due to partial deletion of beta-catenin DNA. It was concluded that in HSC-39 loss of E-cadherin dependent cell-cell adhesion was due to mutation of beta-catenin gene.
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PMID:[Dysfunction of E-cadherin due to mutation of beta-catenin in a scirrhous gastric cancer cell line]. 762 93

Detachment of cell-cell adhesion is indispensable for the first step of invasion and metastasis of cancer. This mechanism is frequently associated with the impairment of either E-cadherin expression or function. However, mechanisms of such abnormalities have not been fully elucidated. In this study, we demonstrated that the function of E-cadherin was completely abolished in the human gastric cancer cell line HSC-39, despite the high expression of E-cadherin, because of mutations in one of the E-cadherin-associated cytoplasmic proteins, beta-catenin. Although immunofluorescence staining of HSC-39 cells by using an anti-E-cadherin antibody (HECD-1) revealed the strong and uniform expression of E-cadherin on the cell surface, cell compaction and cell aggregation were not observed in this cell. Western blotting (immunoblotting) using HECD-1 exhibited a 120-kDa band which is equivalent to normal E-cadherin. Northern (RNA) blotting demonstrated a 4.7-kb band, the same as mature E-cadherin mRNA. Immunoprecipitation of metabolically labeled proteins with HECD-1 revealed three bands corresponding to E-cadherin, alpha-catenin, and gamma-catenin and a 79-kDa band which was apparently smaller than that of normal beta-catenin, indicating truncated beta-catenin. The 79-kDa band was immunologically identified as beta-catenin by using immunoblotting with anti-beta-catenin antibodies. Examination of beta-catenin mRNA by the reverse transcriptase-PCR method revealed a transcript which was shorter than that of normal beta-catenin. The sequencing of PCR product for beta-catenin confirmed deletion in 321 bases from nucleotides +82 to +402. Southern blotting of beta-catenin DNA disclosed mutation at the genomic level. Expression vectors of Beta-catenin were introduced into HSC-39 cells by transfection. In the obtained transfectants, E-cadherin-dependent cell-cell adhesiveness was recovered, as revealed by cell compaction, cell aggregation, and immunoflourescence staining. From these results, it was concluded that in HSC-39 cells, impaired cell-cell adhesion is due to mutations in beta-catenin which results in the dysfunction of E-cadherin.
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PMID:Loss of E-cadherin-dependent cell-cell adhesion due to mutation of the beta-catenin gene in a human cancer cell line, HSC-39. 786 12

Aberrant tyrosine phosphorylation of beta-catenin inactivates the E-cadherin-mediated cell adhesion and invasion suppressor system in cancer cells. Elucidation of the association between beta-catenin and c-erbB-2 protein prompted us to investigate whether interference with this interaction can change the invasive phenotype. In a human gastric cancer cell line, TMK-1, N-terminally deleted beta-catenin, which binds to c-erbB-2 but not to cadherin, inhibited the association between endogenous beta-catenin and c-erbB-2 protein, and suppressed the tyrosine phosphorylation of beta-catenin. Cells expressing truncated beta-catenin exhibited markedly reduced invasiveness in vitro and peritoneal metastasis in vivo, and developed an epithelial morphology. These results suggest that tyrosine phosphorylation of beta-catenin regulated by c-erbB-2 protein may play an important role in the invasion, metastasis and morphogenesis of cancer cells and that inhibition of the aberrant tyrosine phosphorylation of beta-catenin effectively prevents invasion and metastasis of cancer cells.
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PMID:Dominant negative inhibition of the association between beta-catenin and c-erbB-2 by N-terminally deleted beta-catenin suppresses the invasion and metastasis of cancer cells. 880 77

The E-cadherin-mediated cell adhesion system acts as an "invasion suppressor" system, which is widely considered to be inactivated when the expression of E-cadherin is reduced and/or heterogeneous. To further investigate the molecular mechanisms responsible for dysfunction of this system in cancers, we examined human carcinoma cell lines lacking tight cell-cell adhesion. In KATO-III, established from stomach cancer, a point mutation of the E-cadherin gene resulted in a mRNA splicing error and markedly reduced E-cadherin expression. In another stomach cancer cell line, MKN 45, an 18-bp deletion of the E-cadherin gene caused a mRNA splicing error and a 4-amino-acid deletion, which was considered to alter the conformation around the key Ca(2+)-binding motif. In these two cell lines, the wild-type allele of the E-cadherin locus, which was assigned to chromosome 16q, was lost. Also in vivo, we found mutation of E-cadherin in breast cancers, where allele loss on chromosome 16 has frequently been reported. Thus, dysfunction of E-cadherin could be caused by a combination of the loss of one allele and a mutation in the remaining allele. Homologous deletion of part of the alpha-catenin gene, resulting in markedly reduced expression, was observed in a human lung cancer cell line, PC9. Recently, we also found mutations of beta-catenin in human carcinoma cell lines. These findings indicate the possible involvement of genetic abnormalities of various components in inactivation of the E-cadherin-mediated "invasion suppressor system" in cancers.
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PMID:Alterations of the cadherin-catenin cell adhesion system in cancers. 898 63

Tyrosine phosphorylation of beta-catenin, an intracytoplasmic E-cadherin-binding protein, has been shown to disrupt the cadherin-mediated cell adhesion system in vitro. In order to investigate the relationships of expression and tyrosine phosphorylation of cadherin-catenin molecules and expression of growth factor receptor-tyrosine kinase with loose cell-to-cell adhesion, immunohistochemical staining for E-cadherin, alpha- and beta-catenin, phosphorylated tyrosine residues and tyrosine kinase receptors, including c-erbB-2, epidermal growth factor-receptor (EGF-R), c-met and K-sam, in 17 undifferentiated- and 10 differentiated-type human gastric cancers was performed. Loss or reduced expressions of E-cadherin and alpha- and beta-catenin (11, 11, 10 cancers, respectively) were observed in the former, but not the latter. Diffuse cytoplasmic staining of E-cadherin, alpha- and beta-catenin and phosphotyrosine residues was observed frequently in the undifferentiated-type cancers. The cytoplasmic localization of phosphotyrosine residues in undifferentiated-type cancers was correlated significantly with K-sam expression (P < 0.01) and diffuse cytoplasmic staining of E-cadherin (P < 0.05) and beta-catenin (P < 0.05). Expression of K-sam protein was detected significantly more frequently in undifferentiated- (6/17; P < 0.05) than differentiated-type adenocarcinomas whereas the converse applied to c-erbB-2 expression (8/10 of the latter, P < 0.05). Tyrosine phosphorylation of beta-catenin was directly confirmed in the protein extracts of one undifferentiated-type gastric cancer. These data indicate that alteration of tyrosine phosphorylation status associated with K-sam expression may cause the cytoplasmic distribution of cadherin-catenin molecules and loose cell-cell adhesion in undifferentiated-type gastric cancers.
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PMID:Expression of cadherin-catenin cell adhesion molecules, phosphorylated tyrosine residues and growth factor receptor-tyrosine kinases in gastric cancers. 976 19

Adenomatous polyposis coli (APC) mutations are present in >70% of colon cancers. The APC protein binds to beta-catenin (beta-cat), a protein first identified because of its role in E-cadherin (E-cad) cell adhesion. In some colon cancers lacking APC defects, mutations in presumptive glycogen synthase kinase 3beta phosphorylation sites near the beta-cat NH2 terminus appear to render beta-cat resistant to regulation by APC and glycogen synthase kinase 3beta. In cells with APC or beta-cat defects, beta-cat is stabilized and, in turn, binds to and activates T-cell factor (Tcf)/lymphoid enhancer factor (Lef) transcription factors. To further explore the role of APC, beta-cat, Tcf, and E-cad defects in gastrointestinal cancers, we assessed gastric and pancreatic cancers for constitutive Tcf transcriptional activity (CTTA). Two of four gastric and two of eight pancreatic cancer lines showed CTTA. One gastric and one pancreatic cancer had mutations in the NH2-terminal phosphorylation sites of beta-cat. The other gastric cancer with CTTA had a missense mutation at serine 28 of gamma-cat, a potential phosphorylation site in this beta-cat-related protein. Although E-cad is an important binding partner for beta-cat and gamma-cat, E-cad inactivation did not result in CTTA. The beta-cat and gamma-cat mutant proteins identified in our studies strongly activated Tcf transcription in vitro, whereas beta-cat mutant proteins with large NH2-terminal deletions had only modest effects on Tcf. Our results suggest a role for Tcf deregulation in gastric and pancreatic cancer, resulting from beta-cat and gamma-cat mutations in some cases and, in others, from yet to be defined defects. Furthermore, these data imply that the consequences of APC and beta-cat mutations are distinct from the effects of E-cad inactivation.
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PMID:Beta- and gamma-catenin mutations, but not E-cadherin inactivation, underlie T-cell factor/lymphoid enhancer factor transcriptional deregulation in gastric and pancreatic cancer. 1039 98

The increased level of cytoplasmic beta-catenin through the mutations to either beta-catenin or adenomatous polyposis coli (APC) has been proposed as an important oncogenic step in various tumors. Gastric cancer showed frequent genetic alterations of the APC gene, and the risk for gastric cancer in familial adenomatosus polyposis patients is 10 times higher than that in the general population. These findings raise the possibility that mutations of beta-catenin may also be associated with the development of gastric cancer. We detected seven somatic mutations in a portion of exon 3 encoding for the glycogen synthase kinase 3beta phosphorylation consensus region of the beta-catenin gene in 43 gastric cancers. All of these mutations were missense mutations, of which five are in the highly conserved aspartic acid 32 and two are in serine 29; all of these seven mutations were detected exclusively in intestinal-type gastric cancers (7 of 26; 26.9%), but not in the diffuse-type (0 of 17). We concluded that disruption of the APC/beta-catenin/T cell factor-lymphoid enhancer binding factor pathway might play an important role especially in the development of intestinal-type gastric cancer.
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PMID:Frequent somatic mutations of the beta-catenin gene in intestinal-type gastric cancer. 1048 68

The aim of this study was to elucidate the pathogenetic backgrounds of early-onset gastric cancers. Mutations of the E-cadherin and beta-catenin genes were analyzed by subjecting microdissected cancer cells and corresponding non-cancerous epithelial cells obtained from 9 gastric cancer patients under 35 years old to polymerase chain reaction-single strand conformation polymorphism analysis. Somatic, but no germline, E-cadherin gene mutations were detected in 6 (67%) of the patients. The cancer cells of 2 patients were exon 9-deleted E-cadherin molecule-immunoreactive. Neither somatic nor germline mutations in exon 3 of the beta-catenin gene were observed in any patient. One patient lacked beta-catenin immunoreactivity and the cancer cells of 6 others showed cytoplasmic beta-catenin immunoreactivity. The E-cadherin-mediated cell adhesion system in the cancer cells of all the patients examined appeared to be disrupted, indicating that somatically acquired dysfunction of this system plays an important role in early-onset diffuse-type gastric cancers. Helicobacter pylori infection was observed in 6 (67%) of our 9 patients, an incidence higher than the average in young Japanese individuals. Thus, early-onset gastric cancers may be attributable to environmental factors such as Helicobacter pylori infection.
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PMID:Disruption of E-cadherin-mediated cell adhesion systems in gastric cancers in young patients. 1055 30

beta-catenin, a component of the E-cadherin-catenin cell adhesion complex, also plays a separate intracellular signalling role, interacting with APC protein. Intracellular accumulation of beta-catenin is common in colorectal neoplasia. beta-catenin abnormalities are associated with poor survival in gastric cancer, but previous studies do not differentiate between membrane-associated and intracellular beta-catenin. In this study we aimed to determine which type of expression abnormalities for E-cadherin, beta-catenin and alpha-catenin correlate with clinico-pathological features and survival in gastric cancer. Immunoperoxidase staining of paraffin-embedded sections from 40 gastric cancers was performed for E-cadherin, alpha- and beta-catenins using microwave unmasking and an avidin-biotin technique. Clinical data were obtained from case records and cancer registry records. Reduced membranous expression of beta-catenin occurred in 10/12 (83%) diffuse and 8/28 (29%) intestinal tumours (P= 0.0014), and was associated with poor differentiation (P= 0.0015) and short survival (P= 0.032), but not with age, sex, tumour size or nodal status. Nuclear expression of beta-catenin was uncommon; cytoplasmic expression was observed in 13/40 cases (33%) but did not correlate with histology, tumour grade or survival. Reduced E-cadherin membrane expression was associated with lymph node metastasis (P= 0.02). Neither E-cadherin or alpha-catenin expression correlated with survival. Reduced membranous expression of beta-catenin predicts poor prognosis in gastric cancer, whilst ectopic intracellular expression is relatively rare. The apparent differences in beta-catenin expression from those found in colon cancer merit further study.
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PMID:Reduction in membranous expression of beta-catenin and increased cytoplasmic E-cadherin expression predict poor survival in gastric cancer. 1060 38

Molecular characterization of eight gastric cancer cell lines established in Japan are summarized according to the genetic and epigenetic alterations and growth factor status. TMK-1 poorly differentiated adenocarcinoma cell line harbors mutant p53 tumor suppressor gene and rearrangement of p15MTS2. MKN-1 adenosquamous carcinoma line with mutant p53 reveals silencing of E-cadherin by promoter CpG hypermethylation. MKN-7 well-differentiated adenocarcinoma cell line has amplification of c-erbB2 oncogene and cyclin E gene. MKN-28 well-differentiated adenocarcinoma cell line reveals mutations in p53 and APC tumor suppressor genes and silencing of CD44. The MKN-45 poorly differentiated adenocarcinoma cell line with wild-type p53 is characterized by homozygous deletion of p16CDKN2/MTS1/INK4A and p15MTS2, amplification of c-met oncogene and promoter mutation of E-cadherin. MKN-74 derived from moderately differentiated tubular adenocarcinoma has wild-type p53. KATO-III signet ring cell carcinoma line has genomic deletion of p53, amplification of K-sam and c-met oncogene and mutation of E-cadherin. HSC-39 signet ring cell carcinoma cell line harboring p53 missense mutation has homozygous deletion of p16CDKN2/MTS1/INK4A and p15MTS2, amplifications of c-myc, c-met, K-sam and CD44 gene and mutation in beta-catenin gene.
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PMID:Molecular characteristics of eight gastric cancer cell lines established in Japan. 1110 48


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