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

In a highly populated and industrialised zone of the province of Milan (Health Area 68, Rho) a study was made of mortality due to malignant neoplasms of the digestive organs in the years 1980-1987. The highest mortality percentage in both sexes is caused by stomach cancer, followed by neoplasms of the large bowel, particularly of the colon, malignant neoplasms of the pancreas, primary liver cancer and, in males, of the oesophagus. On the whole mortality from malignant neoplasms of the digestive organs is high in subjects over 75 years and in males a little earlier. Age standardised mortality rates of malignant neoplasms of the stomach and intestine are higher in the area being studied than in Italy. However in males mortality from cancer of the large bowel is lower than in Lombardy, especially in middle-aged subjects. The years 1980-87 have shown a statistically significant increasing trend in males of death from cancer of the colon, rectum and liver. There is an identical trend in females as regards cancer of the colon and liver with the addition of stomach cancer but mortality from cancer of the rectum is stationary. In both sexes mortality from malignant neoplasms of the digestive organs is on the increase but in females this coincides with a general increase in cancer mortality as a whole. Differences have emerged, however, between the sexes depending on age: in males the increasing trend refers mainly to the 35-64 year age group and in females to the over 65 age group. This is particularly true in the case of tumours of the large bowel. In the area being examined the middle-aged population was particularly affected by immigration caused by the rapid industrial development of the area in the 1960's and 70's. It is reasonable to assume that the increasing trend in tumours of the digestive organs, and in particular of the large bowel can also be explained by the fact that people coming on the whole from regions with a lower specific risk factor have had to adapt to different life styles and dietary habits that are typical of a highly industrialised metropolitan area. This assumption can be verified with case-control studies or with statistical techniques (e.g. the logistic regression model for the analysis of proportionate mortality data) that are more typical of occupational epidemiology. In this way it would be possible to understand better the effects of living in the area being studied, as well as of more specific risk factors.
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PMID:[Mortality from malignant tumors of the digestive system in an area of the province of Milan from 1980 to 1987]. 248 89

The topographical organisation of the epithelium lining mucous membranes has been an intense point of research. One of the fundamental biological issues underpinning this and associated issues relates to the role and regulation of epithelial adhesion molecules. Adhesion between individual cells allows an intact layer to be formed, which is selectively permeable. In addition, the orchestrated regulation of multiple adhesion molecules allows the gradual transition from basal secretory cells to apical absorptive cells in the crypt-villus gradient. Moreover, it is becoming clear that no one class of adhesion molecule can sufficiently govern crypt architecture; however, the main cell-cell adhesion molecules are the cadherins and the related desmosomal cadherins. These latter molecules interact with the catenins, which bind directly or indirectly with cytoskeletal molecules such as Rho and Rac. In addition, other complex glycoproteins, such as the carcinoembryonic antigens, might contribute to adhesion, although their mechanisms of function are distinctly different. Integrins on the basal aspect of the cells also signal important morphoregulatory signals as a result of their binding to the extracellular maxtrix. The disruption of these physiological processes also provides a necessary and, in some cases, sufficient molecular mechanism for cancer invasion and metastasis, such as occurs in E-cadherin mutation positive familial gastric cancer.
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PMID:Cadherin adhesion in the intestinal crypt regulates morphogenesis, mitogenesis, motogenesis, and metaplasia formation. 1069 34

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

Helicobacter pylori infects over half the world's population and causes a wide range of diseases, including gastritis, peptic ulcer, and two forms of gastric cancer. H. pylori infection elicits a variety of phenotypic responses in cultured gastric epithelial cells, including the expression of proinflammatory genes and changes in the actin cytoskeleton. Both of these responses are mediated by the type IV secretion system (TFSS) encoded by the cag pathogenicity island (cag PAI). We used human cDNA microarrays to examine the temporal transcriptional profiles of gastric AGS cells infected with H. pylori strain G27 and a panel of isogenic mutants to dissect the contributions of various genes in the cag PAI. Infection with G27 induced expression of genes involved in the innate immune response, cell shape regulation, and signal transduction. A mutant lacking the cagA gene, which encodes an effector molecule secreted by the TFSS and required for the host cell cytoskeletal response, induced the expression of fewer cytoskeletal genes. A mutant lacking cagE, which encodes a structural component of the TFSS, failed to up-regulate a superset of host genes, including the cagA-dependent genes, and many of the immune response genes. A mutant lacking the entire cag PAI failed to induce both the cagE-dependent genes and several transiently expressed cagE independent genes. Host cell transcriptional profiling of infection with isogenic strains offered a detailed molecular picture of H. pylori infection and provided insight into potential targets of individual virulence determinants such as tyrosine kinase and Rho GTPase signaling molecules.
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PMID:Cag pathogenicity island-specific responses of gastric epithelial cells to Helicobacter pylori infection. 1241 77

FMNL (NM_005892.2) is a 5'-truncated partial cDNA encoding a Formin-homology protein related to DAAM1, DAAM2, DIAPH1 and DIAPH2. Here, we identified three members of FMNL gene family in the human genome by using bioinformatics. FMNL1 gene, corresponding to 5'-truncated KW-13 and FMNL cDNAs, was located within reference genomic contig NT_010748.9 (nucleotide position 100576-125849, forward orientation). FMNL2 gene, corresponding to KIAA1902 and FHOD2 cDNAs, was located within NT_005151.10 (nucleotide position 122465-436828, forward orientation). FMNL3 gene, corresponding to 5'-truncated DKFZp762B245 and KIAA2014 cDNAs, was located within NT_026397.10 (nucleotide position 209769-279037, reverse orientation). FMNL1, FMNL2 and FMNL3 genes encode A and B isoforms with the C-terminal divergence due to alternative splicing (cassette splicing of exon 26). FMNL1A (1100 aa), FMNL1B (1114 aa), FMNL2A (1087 aa), FMNL2B (1093 aa), FMNL3A (1028 aa) and FMNL3B (1027 aa) consist of FDD, FH1 and FH2 domains. Total amino-acid identity were as follows: FMNL1A vs. FMNL2A, 59.3%; FMNL1A vs. FMNL3A, 56.1%; FMNL2A vs. FMNL3A, 68.6%. FMNL1 gene was mapped to human chromosome 17q21. FMNL2 gene was linked to FNBP3/HYPA gene on chromosome 2q23.3, while FMNL3 gene was linked to FNBP3L/HYPC gene on chromosome 12q13. FMNL1 mRNA was expressed in natural killer cells, Burkitt lymphoma, pancreatic cancer, prostate cancer, and lung large cell carcinoma, FMNL2 mRNA in several normal tissues, diffuse-type gastric cancer, breast cancer, chondrosarcoma, melanoma, and glioblastoma, and FMNL3 mRNA in gastric cancer. FMNL1, FMNL2 and FMNL3 might be implicated in polarity control, invasion, migration, or metastasis through regulation of the Rho-related signaling pathway.
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PMID:Identification and characterization of human FMNL1, FMNL2 and FMNL3 genes in silico. 1268 86

Epithelial cell responses to bacterial infection include induction of matrix metalloproteinase 7 (MMP-7). Here, we identify increased MMP-7 expression in the gastric epithelium in response to the oncogenic bacterium Helicobacter pylori, and report on the mechanisms and consequences for gastric epithelial cell migration. In patients infected with H. pylori, there was increased MMP-7 in gastric biopsies detected by western blot. MMP-7 was localized to the advancing edge of migrating gastric epithelial cell colonies, including lamellipodia. Rates of spreading of gastric gland cells were higher in H. pylori-infected cultures compared with control, and this was inhibited by antisense oligonucleotides to MMP-7. Complementary data were obtained in a gastric cancer cell line (AGS cells). In the latter, H. pylori induced expression of an MMP-7-luciferase promoter/reporter vector through mechanisms that involved activation of Rho and Rac. RhoA acted through activation of both NF-kappaB and AP-1, whereas Rac activated NF-kappaB but not AP-1. MMP-7 is commonly upregulated in gastric cancer; since H. pylori is a recognized gastric carcinogen, the data suggest a new mechanism by which the bacterium might predispose towards gastric neoplasia.
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PMID:Stimulation of MMP-7 (matrilysin) by Helicobacter pylori in human gastric epithelial cells: role in epithelial cell migration. 1280 21

Rho GTPases were previously shown to have an important role in cancer development and progression, including cell transformation, proliferation, invasion, metastasis, and angiogenesis. However, there is still little information available on the clinical significance of Rho GTPases expression in human cancer specimens. In the present study, we systemically investigated the mRNA expression levels of seven main members RhoA, RhoB, RhoC, Rac1, Rac2, Rac3, and Cdc42 of Rho family using semi-quantitative reverse transcription-PCR in 53 patients with gastric carcinoma and 7 gastric cancer cell lines. The total and activities of RhoA, Rac1 and Cdc42 in 5 gastric cancer cell lines were also examined. The mean mRNA expression levels of RhoA and Rac1 in gastric cancer tissue specimens were significantly higher than those in the adjacent non-tumorous tissue specimens (p < 0.01). The higher expression of RhoA was significantly correlated with higher TNM stage (p < 0.05) as well as with pooly differentiated histological type (p < 0.05) of gastric carcinoma. The increased expression of Rac1 was related to higher TNM stages of gastric carcinoma (p < 0.05). The expression levels of mRNA, total protein and activities of RhoA and Rac1 in 7 gastric cancer cell lines were all higher than that in gastric mucosal epithelial cell line GES-1. These findings indicate that RhoA and Rac1 may play important roles in the carcinogenesis and progression of gastric carcinoma.
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PMID:Expression of seven main Rho family members in gastric carcinoma. 1497 55

The expression of members of the Reg family of secreted lectin-like proteins is increased in response to stress, inflammation and damage in many tissues. In the stomach, Reg is located in enterochromaffin-like cells, where its expression is stimulated by the gastric hormone gastrin. We have examined the mechanisms by which gastrin stimulates expression of Reg-1. Deletional mutations of 2.1 to 0.1 kb of the rat Reg-1 promoter in a luciferase reporter vector were transiently transfected into gastric cancer AGS-G(R) cells. All promoter fragments tested showed similar relative increases in luciferase expression in response to gastrin (1 nM). The response to gastrin of the smallest (104 bp) construct was 4.2+/-0.4-fold over basal. These responses were reduced by Ro-32-0432, a protein kinase C inhibitor, by C3-transferase, a Clostridium botulinum toxin and a selective inhibitor of the Rho family GTPase RhoA, and by co-transfection with a dominant negative form of RhoA. Co-transfection with a constitutively active form of RhoA stimulated expression 11.6+/-1.7-fold over basal. Mutations through the 104 bp construct identified a C-rich element (C-79CCCTCCC-72) required for responses to gastrin, PKC (protein kinase C) and L63RhoA (the constitutively active form of human RhoA protein containing a glutamine-to-leucine substitution at position 63). EMSAs (electrophoretic-mobility-shift assays) using nuclear extracts of control and gastrin-stimulated AGS-G(R) cells and a probe spanning -86 to -64 bp revealed multiple binding proteins. There was no effect of gastrin on the pattern of binding. Supershift assays indicated that transcription factors Sp1 and Sp3 bound the C-rich sequence. We conclude that gastrin stimulates Reg expression via activation of PKC and RhoA, that a C-rich region (-79 to -72) is critical for the response and that Sp-family transcription factors bind to this region of the promoter.
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PMID:Control of expression of the lectin-like protein Reg-1 by gastrin: role of the Rho family GTPase RhoA and a C-rich promoter element. 1510 6

Hypoxia-induced angiogenesis plays an important role in the malignancy of solid tumors. A number of recent studies including our own have suggested that Rho family small GTPases are involved in this process, and Racl, a prominent member of the Rho family, may be critical in regulating hypoxia-induced gene activation of several angiogenesis factors and tumor suppressors. To fur-ther define Racl function in angiogenesis and to explore novel approaches to modulate angiogenesis, we employed the small interference RNA technique to knock down gene expression of Racl in gastric cancer cell line AGS that expresses a high level of Racl. Both the mRNA and protein levels of Racl in the AGS cells were decreased dramatically after transfection with a Racl-specific siRNA vector. When the conditioned medium derived from the Racl downregulated AGS cells was applied to the human endothelial cells. it could significantly inhibit the cell proliferation. Further study proved that, VEGF and HIF-la, two angiogenesis promoting factors, were found to be downregulated whereas p53 and VHL, which are tumor suppressors and angiogenesis inhibitors. were upregulated in the Racl siRNA transfected cells. Our results suggest that Racl may be involved in angiogenesis by controlling the expression of angiogenesis-related factors and provide a possible strategy for the treatment of tumor angiogenesis by targeting the Racl GTPase.
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PMID:Inhibition of endothelial cell proliferation by targeting Rac1 GTPase with small interference RNA in tumor cells. 1530 76

Like many epithelial-derived cancers, gastric cancer (GC) results from a multistep tumorigenic process. However, the detailed mechanisms involved in GC formation are poorly characterized. Using an ordered differential display method, we have identified rhotekin (RTKN), the gene coding for the Rho effector, RTKN, as one of the genes differentially expressed in human GC. Northern analysis using human multiple tissue blots showed that RTKN is predominantly expressed in the kidney and spinal cord, and, to a lesser degree, in the thyroid, tongue, liver, brain, prostate, trachea, and stomach. RT-PCR analysis confirmed that RTKN was overexpressed in most (5/7; 71%) GC examined. By analyzing the Stanford Microarray Database for the expression profiles of gastric tissues, we also found a progressional increase in RTKN expression in nonneoplastic mucosa, GC, and then lymph node metastases (p < 0.005 by Jonckheere-Terpstra test), suggesting that RTKN expression correlates with GC progression. The role of RTKN in the pathogenic development of GC was investigated by transfection and expression of RTKN in AGS gastric cells, which express endogenous RTKN at a low basal level. Flow-cytometric analysis showed that RTKN-transfected AGS cells were significantly more resistant than vector-transfected cells to apoptosis upon treatment with sodium butyrate. To explore the mechanisms underlying RTKN-mediated cell survival, a reporter assay was performed. Since the NF-kappaB activation is known to promote cell survival and Rho GTPase may lead to NF-kappaB activation, we transfected AGS cells with the RTKN expression vector along with a pNF-kappaB-Luc reporter plasmid. Our results showed that overexpression of RTKN induced robust activation of NF-kappaB, and RTKN-mediated NF-kappaB activation was suppressed significantly by C3 transferase, an inhibitor of the small GTPase Rho. We conclude that Rho/RTKN-mediated NF-kappaB activation leading to cell survival may play a key role in gastric tumorigenesis. This study provides original documentation for the overrepresentation of the Rho GTPase effector rhotekin in human cancer and its links to cancer formation.
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PMID:Overexpression of rho effector rhotekin confers increased survival in gastric adenocarcinoma. 1531 42


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