Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

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

Abnormal expression of E-cadherin/catenin complex in cancer has been associated with poor differentiation and acquisition of invasiveness, suggesting a possible role of this protein as an invasion suppressor. In this study, we conducted an immunohistochemical investigation of all components of the E-cadherin/catenin complex in 65 gastric cancer patients. Abnormal expression of E-cadherin and, alpha- and gamma-catenin occurred more frequently in diffuse than in intestinal type of gastric cancer, and correlated with poor differentiation. Abnormal expression of E-cadherin and beta-catenin correlated with poor survival. Abnormal expression of all four components of the complex was associated with poorly differentiated and diffuse-type carcinoma, and poor survival. In the multivariate analysis, abnormal expression of the E-cadherin/catenin complex was not an independent prognostic factor. These results suggest that the E-cadherin/catenin complex may be a useful marker of differentiation and prognosis in gastric cancer. Further studies are warranted to clarify the impact of the E-cadherin/catenin complex on prognostic factor of gastric cancer.
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PMID:Prognostic significance of E-cadherin/catenin complex expression in gastric cancer. 1119 92

Down-regulation of E-cadherin function is characteristic of cancer cells and might involve the small G-protein Rho family, including Rac1 and Cdc42. IQGAP1 has been reported to be one of the target proteins of Rac1 and Cdc42. To elucidate the role of IQGAP1 in cancer-cell adhesion, its expression was investigated in 47 cases of human gastric cancer by immunohistochemistry and Western blot upon protein fractionation, especially in comparison with E-cadherin and catenin expression. In the non-cancerous columnar epithelium of the stomach, IQGAP1, as well as E-cadherin/catenin, was expressed at the cell-cell boundary. IQGAP1 was frequently observed diffusely in the cytoplasm in intestinal-type tumors (20/22 cases) but was expressed at the cell membrane in diffuse-type tumors (19/25 cases), thus showing significant association with tumor differentiation (p < 0.01). Interestingly, membranous expression of IQGAP1 was inversely correlated with that of E-cadherin (p < 0.05) or alpha-catenin (p < 0.001). These observations were consistent with the Western blot results following protein fractionation. IQGAP1 was dominantly expressed in the soluble fraction in differentiated tumors; however, in undifferentiated tumors, it was mostly in the insoluble fraction. In contrast, both E-cadherin and alpha-catenin were detected only in the insoluble fraction. Thus, subcellular localization of IQGAP1 from the cytoplasm to the cell membrane was correlated with E-cadherin dysfunction and tumor dedifferentiation in gastric carcinogenesis.
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PMID:Localization of IQGAP1 is inversely correlated with intercellular adhesion mediated by e-cadherin in gastric cancers. 1127 80

Our previous comparative genomic hybridization (CGH) study revealed a novel amplified region at 15q26 in two cell lines established from diffuse types of gastric cancer (GC). In this amplified region, FES and IGF1R, known targets on 15q26, were located telomeric to the amplicon in the two cell lines, HSC39 and 40A, suggesting that another tumor-associated gene exists in this region. While screening expressed sequence tags (ESTs) for novel genes in this region, we identified the IQGAP1 amplification. IQGAP1 has been reported to encode a ras GAP-related protein, and its interaction with cadherin and/or beta-catenin induces a dissociation of beta-catenin from the cadherin-catenin complex, one of the mechanisms for cell-cell adhesion. Northern and Western blot analyses revealed that amplification of this gene was accompanied by corresponding increases in mRNA and protein expression. Moreover, immunocytochemical staining showed that overexpressed IQGAP1 accumulated at the membrane, suggesting its colocalization with beta-catenin. Taken together, these findings suggest that IQGAP1 may be one of the target genes in the 15q26 amplicon correlated with a malignant phenotype of gastric cancer cells, such as diffuse and invasive characteristics, through the disruption of E-cadherin-mediated cell-cell adhesion.
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PMID:IQGAP1, a negative regulator of cell-cell adhesion, is upregulated by gene amplification at 15q26 in gastric cancer cell lines HSC39 and 40A. 1128 14

Nectin is an immunoglobulin-like adhesion molecule that comprises a family consisting of four members, nectin-1, -2, -3, and -4. Nectin is associated with the actin cytoskeleton through afadin, a nectin- and actin filament-binding protein. The nectin-afadin and cadherin-catenin systems are associated with each other and cooperatively form cell-cell adherens junctions in intact epithelial cells. HSC-39 cells, a human signet ring cell gastric cancer cell line, express E-cadherin but do not form cell-cell adhesion. The beta-catenin gene has been shown to be truncated at the N-terminal region including the alpha-catenin-binding domain in HSC-39 cells, but overexpression of normal beta-catenin failed to form cell-cell adhesion. HSC-39 cells expressed nectin-1, -2, and afadin, but not nectin-3. Overexpression of nectin-3 or -2 formed cell-cell adhesion and accumulation of E-cadherin, but not actin filaments, at the cell-cell adhesion sites. Overexpression of a truncated form of nectin-2 incapable of interacting with afadin failed to form cell-cell adhesion. However, the nectin-formed cell-cell adhesion was not so strong as that observed in epithelial cells, such as CaCo-2 cells. Co-expression of nectin-2 and normal beta-catenin did not form strong cell-cell adhesion. These results suggest that an unidentified mechanism, by which nectin and E-cadherin form the actin cytoskeleton-associated adherens junctions to form strong cell-cell adhesion, is impaired in HSC-39 cells.
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PMID:Restoration of E-cadherin-based cell-cell adhesion by overexpression of nectin in HSC-39 cells, a human signet ring cell gastric cancer cell line. 1203 67

The cadherin-catenin complex has been recognized as an important factor associated with tumor metastasis. However, the clinical significance of the expression of adhesion molecules in lymph nodes with metastasis remains unclear. The aim of this study was to investigate the clinical significance of the re-expression of the cadherin-catenin complex in metastatic lymph nodes in patients with advanced gastric cancer. Immunohistochemical expression of E-cadherin, alpha- and beta-catenin were analyzed in 96 primary gastric cancers with serosal invasion and in 79 lymph nodes with metastasis. The expression levels of these adhesion molecules in primary tumors and lymph nodes with metastasis were compared. Ninety-four out of 96 primary tumors (98%) showed reduced expression of adhesion molecules. Out of 79 cases with lymph node metastasis, increased expression of one or more adhesion molecules in metastatic foci as compared with primary tumors was detected in 52 cases (66%). Re-expression of adhesion molecules in metastatic lymph nodes was detected in a more advanced stage. The overall 5-year survival rate of the 52 patients who had lymph nodes with metastasis with re-expression of adhesion molecules (8%) was significantly poorer than that of the 27 who had lymph nodes with metastasis without re-expression of adhesion molecules (33%, P = 0.0012). The re-expression of the cadherin-catenin complex in lymph nodes with metastasis may play an important role in the growth of cancer cells in metastatic foci. A comparison of the expression patterns of adhesion molecules between the primary tumor and metastatic lymph nodes may provide new prognostic information for patients with advanced gastric cancer.
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PMID:Re-expression of the cadherin-catenin complex in lymph nodes with metastasis in advanced gastric cancer: the relationship with patient survival. 1207 32

E-cadherin and its associated cytoplasmic proteins including alpha-, beta-, and gamma-catenin play a pivotal role in the maintenance of normal tissue architecture and the suppression of cancer invasion. The purpose of this study was to evaluate the expression of E-cadherin and alpha-, beta-, and gamma-catenin in a larger sample of early gastric cancer, and to examine the relation between these expressions and various clinicopathologic variables. The expression of E-cadherin and alpha-, beta-, and gamma-catenin was investigated using immunohistochemical technique with formalin-fixed, paraffin-embedded tissue specimens obtained from 108 patients who underwent surgery for early gastric cancer. In the gastric mucosa of noncancerous areas, epithelial cells showed equally strong membranous expression of E-cadherin and alpha-, beta-, and gamma-catenin proteins at the cell-cell boundaries. Reduced expression of E-cadherin and alpha-, beta-, and gamma-catenin was demonstrated in 43.5%, 39.8%, 42.6%, and 50% of cancer tissues, respectively. Whereas 34 tumors (31.5%) displayed preserved expression of all four E-cadherin-catenin complex components, 21 tumors (19.4%) displayed reduced expression of all components of this complex. Reduced expression of E-cadherin and alpha- and gamma-catenin occurred more frequently in diffuse than in intestinal types of cancer, and decreased expression of E-cadherin and alpha-, beta-, and gamma-catenin correlated with poor differentiation. The expression of E-cadherin and beta- and gamma-catenin did not correlate with the patient's age, gender, tumor size, location, macroscopic type, depth of invasion, or lymph node metastasis. Only reduced expression of alpha-catenin correlated with lymph node metastasis. Reduced expression of all four E-cadherin-catenin complex components correlated with poorly differentiated and diffuse-type cancers, but not with the patient's age, gender, tumor size, location, macroscopic type, depth of invasion, or lymph node metastasis. These results suggest that dysfunction of the E-cadherin-catenin complex occurs in an early stage of carcinogenesis, playing a crucial role in disruption of tissue architecture and loss of differentiation in early gastric cancer.
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PMID:Expression of e-cadherin and catenins in early gastric cancer. 1208 Feb 24

Gastric cancer not located in the cardia still remains the second most common cancer worldwide, whereas adenocarcinoma of the cardia and gastroesophageal junction has been rapidly rising over the past two decades. Gastric cancer can be subdivided into two distinct pathologic entities, diffuse and intestinal, that have different epidemiologic and prognostic features. Various genetic and environmental factors play important roles in gastric carcinogenesis; both lead to either abnormal genes overexpression or inappropriate expression of normal genes, whose products confer the malignant phenotype. Advances have been made in the genetic changes mostly of the intestinal type; its development is probably a multistep process, as has been well described in colon cancer pathogenesis, whereas it remains tentative whether the diffuse type of malignancy follows an analogous progression. The most common genetic abnormalities in gastric cancer tend to be loss of heterozygosity of tumor suppressor genes, particularly of p53 or "Adenomatous Polyposis Coli" gene. The latter leads to gastric oncogenesis through changes related to E-cadherin-catenin complex, which plays a critical role in the maintenance of normal tissue architecture. Mutation of any of its components results in loss of cell-cell adhesion, thereby contributing to neoplasia. E-cadherin/CDH1 gene germline mutations have been recognized in families with an inherited predisposition to gastric cancer of the diffuse type. Amplification and/or overexpression of putative trophic factors have also been observed in gastric cancer. Finally, Helicobacter pylori (H. pylori) infection is also involved in gastric carcinogenesis through various mechanisms, thereby necessitating H. pylori eradication in patients with gastric cancer.
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PMID:New concepts of molecular biology on gastric carcinogenesis. 1600 83

CagA protein is a major virulence factor of Helicobacter pylori, which is delivered into gastric epithelial cells and elicits growth factor-like responses. Once within the cells, CagA is tyrosine phosphorylated by Src family kinases and targets host proteins required to induce the cell responses. We show that the phosphorylated CagA binds Crk adaptor proteins (Crk-II, Crk-I, and Crk-L) and that the interaction is important for the CagA-mediated host responses during H. pylori infection. H. pylori-induced scattering of gastric epithelial cells in culture was blocked by overexpression of dominant-negative Crk and by RNA interference-mediated knockdown of endogenous Crk. H. pylori infection of the gastric epithelium induced disruption of E-cadherin/catenin-containing adherens junctions, which was also dependent on CagA/Crk signaling. Furthermore, inhibition of the SoS1/H-Ras/Raf1, C3G/Rap1/B-Raf, or Dock180/Rac1/Wiskott-Aldrich syndrome protein family verprolin homologous protein pathway, all of which are involved downstream of Crk adaptors, greatly diminished the CagA-associated host responses. Thus, CagA targeting of Crk plays a central role in inducing the pleiotropic cell responses to H. pylori infection that cause several gastric diseases, including gastric cancer.
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PMID:Interaction of CagA with Crk plays an important role in Helicobacter pylori-induced loss of gastric epithelial cell adhesion. 1627 61


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