Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the molecular characterization of 8 primary gastric carcinomas, corresponding xenografts, and 2 novel gastric carcinoma cell lines. We compared the tumors and cell lines, with respect to histology, immunohistochemistry, copy number, and hypermethylation of up to 38 genes using methylation-specific multiplex ligation-dependent probe amplification, and TP53 and CDH1 mutation analysis where relevant. The primary tumors and xenografts were histologically comparable and shared expression of 11 of 14 immunohistochemical markers (E-cadherin, beta-catenin, COX-2, p53, p16, TFF1, cyclin E, MLH1, SMAD4, p27, KLK3, CASR, CHFR, and DAPK1). Gains of CASR, DAPK1, and KLK3--not yet described in gastric cancer--were present in the primary tumors, xenografts, and cell lines. The most prominent losses occurred at CDKN2A (p16), CDKN2B (p15), CDKN1B (p27/KIP1), and ATM. Except for ATM, these losses were found only in the cell line or xenograft, suggesting an association with tumor progression. However, examination of p16 and p27 in 174 gastric cancers using tissue microarrays revealed no significant correlation with tumor stage or lymph node status. Further losses and hypermethylation were detected for MLH1, CHFR, RASSF1, and ESR, and were also seen in primary tumors. Loss of CHFR expression correlated significantly with the diffuse phenotype. Interestingly, we found the highest rate of methylation in primary tumors which gave rise to cell lines. In addition, both cell lines harbored mutations in CDH1, encoding E-cadherin. Xenografts and gastric cancer cell lines remain an invaluable research tool in the uncovering of the multistep progression of cancer. The frequent gains, losses, and hypermethylation reported in this study indicate that the involved genes or chromosomal regions may be relevant to gastric carcinogenesis.
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PMID:Molecular analysis of primary gastric cancer, corresponding xenografts, and 2 novel gastric carcinoma cell lines reveals novel alterations in gastric carcinogenesis. 1737 10

Genetic factors, Helicobacter pylori infection, salt over-uptake, decreased vegetable/fruit consumption, smoking, and metabolic syndrome are risk factors of human gastric cancer. Germline mutations of CDH1 gene, and SNPs of PTPN11 (SHP2), TLR4, IL1B, TNFA, BMP6, GDF15 and RUNX3 genes are associated with gastric cancer. Helicobacter pylori activates CagA-SHP2-ERK and peptidoglycan-NOD1-NFkappaB signaling cascades in gastric epithelial cells using type IV secretion system, and also TRAF6-MAP3K7-NFkappaB and TRAF6-MAP3K7-AP-1 signaling cascades in epithelial and immune cells through lipopolysaccharide recognition by TLR2 or TLR4. IL-1beta, IL-6, IL-8, TNFalpha and IFNgamma are elevated in gastric mucosa with Helicobacter pylori infection. IL-6 and TNFalpha induce upregulation of WNT5A and WNT10B, respectively. WNT signals are transduced to beta-catenin-TCF/LEF, RhoA, JNK, PKC, NFAT, and NLK signaling cascades. WNT-beta-catenin-TCF/LEF signaling induces upregulation of MYC, CCND1, WISP1, FGF20, JAG1 and DKK1 genes. Notch signals are transduced to CSL-NICD-MAML and NFkappaB signaling cascades. FGF signals are transduced to ERK, PI3K-AKT, PKC, and NFAT signaling cascades. Helicobacter pylori infection induces SHH upregulation in parietal cell lineage, while BMP signals induce IHH upregulation in pit cell lineage. Hedgehog signals induce upregulation of GLI1, PTCH1, CCND2, FOXL1, JAG2 and SFRP1 genes. JAG1 and JAG2 activate Notch signaling, while DKK1 and SFRP1 inhibit WNT signaling. Stem cell signaling network, consisting of WNT, Notch, FGF, Hedgehog and BMP signaling pathways, is activated during chronic Helicobacter pylori infection. Epigenetic silencing of SFRP1 gene occurs in the earlier stage of carcinogenesis in the stomach, while amplification and overexpression of FGFR2 gene in the later stage. Dysregulation of the stem cell signaling network due to the accumulation of germline mutation, SNP, Helicobacter pylori infection, epigenetic change and genetic alteration gives rise to gastric cancer. SNP typing and custom-made microarray analyses on genes encoding stem cell signaling molecules could be utilized for the personalized medicine.
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PMID:Dysregulation of stem cell signaling network due to germline mutation, SNP, Helicobacter pylori infection, epigenetic change and genetic alteration in gastric cancer. 1756 83

Germ line mutations of the p53 gene are known to cause Li-Fraumeni syndrome, and a germ line p53 mutation has recently been reported in a small subset of familial gastric cancer (FGC) in Europe and Korea. Although the incidence of gastric cancer is very high in Japan and familial clustering is not uncommon, there has been little information on the genetic factors of FGC. Therefore, to determine the role of germ line p53 mutations in FGC in the Japanese population in this study, we used sequencing analysis to examine 80 individuals from 35 Japanese FGC families without germ line CDH1 mutations for germ line p53 mutations. One missense (c.91G>A: p.Val31Ile) and two intronic germ line mutations were found, and transcriptional activity of the Ile31 mutant on p53-responsive genes was examined to determine the functional effect of the novel p.Val31Ile germ line mutation. A luciferase reporter assay showed that the transcriptional activity of p21 (CDKN1A) and MDM2 promoters but not of the BAX promoter was significantly lower in the Ile31-type p53 than in the wild-type (wt) p53. Next, doxycycline-regulated p53-inducible H1299 cell lines were established by applying a retrovirus-mediated gene transfer system to a p53-null human H1299 cell line. Under similar p53 expression conditions shown by western blot and immunofluorescence analyses, a cell proliferation assay showed that the Ile31-type p53 had significantly lower cell proliferation suppressing activity than wt p53. These results suggest that Ile31-type p53 may be partly involved in FGC because of its low transcriptional activity and low cell proliferation suppressing activity.
Carcinogenesis 2007 Sep
PMID:Identification and characterization of a novel germ line p53 mutation in familial gastric cancer in the Japanese population. 1769 Jan 13

Gastric adenocarcinoma not located in the cardia still remains second only to lung cancer as the leading cause of cancer-related mortality worldwide, whereas adenocarcinoma of the cardia and gastroesophageal junction has been rapidly rising over the past two decades. Gastric malignancy can be subdivided into diffuse and intestinal pathologic entities that have different epidemiological and prognostic features. Various genetic and environmental factors lead to either abnormal gene overexpression or inappropriate expression of normal genes, whose products confer the malignant phenotype. Advances have been made in genetic changes mostly of the intestinal type; its development is probably a multistep process, as has been well described in colon carcinogenesis. Oncogene overexpression, tumor suppressor loss, and defective DNA mismatch repair is associated with gastric cancer. The most common genetic abnormalities tend to be loss of heterozygosity of particularly tumor suppressor p53 gene or "adenomatous polyposis coli" gene. The latter leads to gastric carcinogenesis through changes related to E-cadherin-catenin complex, which plays a critical role in normal tissue architecture maintenance. Mutation of any of its components results in loss of cell-cell adhesion, thereby contributing to malignancy. Putative trophic factors have also been involved in gastric oncogenesis. E-cadherin/CDH1 gene germline mutations have been recognized in families with an inherited predisposition to diffuse-type malignancy. This review focuses mainly on Helicobacter pylori infection involved in gastric carcinogenesis through various mechanisms, including repopulation of the stomach with bone marrow-derived stem cells that may facilitate gastric cancer progression, thereby necessitating eradication of this bacterium.
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PMID:New aspects of Helicobacter pylori infection involvement in gastric oncogenesis. 1772 Jan 95

As a critical ubiquitin ligase, the anaphase-promoting complex/cyclosome (APC/C) governs cell cycle progression, signaling modulation and the pathogenesis of some human diseases. Recent studies implicate APC in maintaining genomic integrity, but the mechanism by which it plays such a role remains largely unknown. We report here that acute UV radiation triggers proteolysis of CDH1, an activator of APC, which is involved in regulation of apoptosis induced by UV radiation. Depletion of CDH1 by RNA interference enhances the cellular susceptibility to apoptosis in response to UV radiation, whereas overexpression of non-degradable CDH1 delays UV radiation-induced apoptosis. In addition, UV-induced degradation of CDH1 results in the accumulation of cyclin B1 and therefore to increased CDK1 activity, which is believed to enhance UV-induced apoptosis. The present results unveil a novel role for the APC in UV-induced cell death and demonstrate a new regulatory mechanism for APC/CDH1 through proteolysis.
Carcinogenesis 2008 Feb
PMID:Proteolysis of CDH1 enhances susceptibility to UV radiation-induced apoptosis. 1817 59

Cyclin D1 (CCND1) and E-cadherin (CDH1) have been shown to be important genes of the beta-catenin/LEF pathway that is involved in colorectal carcinogenesis. However, epidemiological studies on relationship between genetic variants of these two genes and colorectal cancer (CRC) have shown inconsistent results. In a population-based case-control study (498 cases and 600 controls), we assessed the association of CCND1 G870A and CDH1 C-160A polymorphisms with CRC risk. Multivariable logistic regression analysis was used to estimate the association between genotypes, environmental exposures and CRC risk, adjusting for potential confounders. Compared to common homozygotes, the OR for heterozygous and homozygote variant genotype was 1.08 (95% CI, 0.80-1.46) in CCND1 and 0.97 (95% CI, 0.75-1.25) in CDH1. Neither tumor stage nor location showed an association with genetic susceptibility. However, a significant interaction between hormone replacement therapy (HRT) and CCND1 genotypes in CRC risk was found among postmenopausal women (p(interaction) = 0.02). The risk reduction associated with HRT was substantial (OR, 0.09; 95% CI, 0.02-0.35) in women who were GG homozygous. A meta-analyses including 11 published studies on CCND1 G870A in addition to our study showed a slightly increased risk of CRC for carriers of the A allele (OR, 1.19; 95% CI, 1.06-1.34); however, there was some indication of publication bias. We conclude that the CCND1 G870A and CDH1 C-160A polymorphisms are not associated with the risk of CRC in the German population. However, the CCND1 G870A polymorphism may modify the protective effect of postmenopausal hormone use on the development of CRC.
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PMID:The association of cyclin D1 G870A and E-cadherin C-160A polymorphisms with the risk of colorectal cancer in a case control study and meta-analysis. 1819 81

Although mutations of APC, CTNNB1 (beta-catenin) and AXIN1 are rare in oral squamous cell carcinoma (OSCC), activation of the Wnt signaling pathway is thought to play an important role in oral carcinogenesis. In the present study, we examined the relationship between Wnt signaling and epigenetic alteration of the secreted frizzled-related protein (SFRP) genes in OSCC. We frequently detected loss of membrane localization of beta-catenin and its cytoplasmic or nuclear accumulation in OSCC cell lines, although these cell lines showed no APC or CTNNB1 (beta-catenin) mutations and no methylation of CDH1 (E-cadherin). By contrast, we frequently detected methylation of SFRP1 (7/17, 41%) SFRP2 (16/17, 94%) and SFRP5 (14/17, 82%) in a panel of OSCC cell lines, as well as in specimens of primary tumors collected from 44 OSCC patients (SFRP1, 10/42, 24%; SFRP2, 16/44, 36%; SFRP5, 7/43, 16%). We also observed that OSCC cell lines express various Wnt ligands, and that ectopic expression of SFRPs inhibited cancer cell proliferation. Our results confirm the frequent methylation and silencing of SFRP genes in OSCC, and suggest that their loss of function contributes to activation of Wnt signaling that leads to cell proliferation during oral carcinogenesis.
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PMID:Epigenetic inactivation of SFRP genes in oral squamous cell carcinoma. 1849 87

SHH, IHH, and DHH are lipid-modified secreted proteins binding to Patched receptors, and CDON, BOC or GAS1 co-receptors. In the absence of Hedgehog signaling, GLI1 is transcriptionally repressed, GLI2 is phosphorylated by GSK3 and CK1 for the FBXW11 (betaTRCP2)-mediated degradation, and GLI3 is processed to a cleaved repressor. In the presence of Hedgehog signaling, Smoothened is relieved from Patched-mediated suppression due to the Hedgehog-dependent internalization of Patched, which leads to MAP3K10 (MST) activation and SUFU inactivation for the stabilization and nuclear accumulation of GLI family members. GLI activators then upregulate CCND1, CCND2 for cell cycle acceleration, FOXA2, FOXC2, FOXE1, FOXF1, FOXL1, FOXP3, POU3F1, RUNX2, SOX13, TBX2 for cell fate determination, JAG2, INHBC, and INHBE for stem cell signaling regulation. Hedgehog signals also upregulate SFRP1 in mesenchymal cells for WNT signaling regulation. Epithelial-to-mesenchymal transition (EMT) during embryogenesis, adult tissue homeostasis and carcinogenesis is characterized by class switch from E-cadherin to N-cadherin. SNAI1 (Snail), SNAI2 (Slug), SNAI3, ZEB1, ZEB2 (SIP1), KLF8, TWIST1, and TWIST2 are EMT regulators repressing CDH1 gene encoding E-cadherin. Hedgehog signals induce JAG2 upregulation for Notch-CSL-mediated SNAI1 upregulation, and also induce TGFbeta1 secretion for ZEB1 and ZEB2 upregulation via TGFbeta receptor and NF-kappaB. TGFbeta-mediated downregulation of miR-141, miR-200a, miR-200b, miR-200c, miR-205, and miR-429 results in upregulation of ZEB1 and ZEB2 proteins. Hedgehog signaling activation indirectly leads to EMT through FGF, Notch, TGFbeta signaling cascades, and miRNA regulatory networks. miRNAs targeted to stem cell signaling components or EMT regulators are potent drug targets; however, off-target effects should be strictly controlled before clinical application of synthetic miRNA. Peptide mimetic and RNA aptamer could also be utilized as Hedgehog signaling inhibitors or EMT suppressors.
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PMID:Hedgehog signaling, epithelial-to-mesenchymal transition and miRNA (review). 1869 84

DNA methylation is one of the major events in the early process of gastric carcinogenesis and it also occurs in non-neoplastic gastric mucosa. MTHFR plays a central role in biotransformation of folate to form S-adenosylmethionine, the universal methyl donor in cells and affects DNA methylation status. We investigated the association between common functional polymorphism of MTHFR C677T and DNA methylation status in H. pylori-infected non-neoplastic gastric mucosa. For 99 gastric mucosa samples from H. pylori positive non-cancer subjects, we assessed the association between MTHFR C677T genetic polymorphism and promoter methylation status of the four candidate promoters (p14, p16, DAP-kinase, and CDH1). In most all of the subjects, weak correlation was found between the p16 promoter methylation and MTHFR 677T carriers (age, sex-adjusted OR = 2.57, P = 0.053). When subjects were divided into two groups according to age, the MTHFR T carrier held a significantly higher risk of p16 promoter methylation, especially in 66 years or older generation (sex-adjusted OR = 14.28, P = 0.02). In addition, mean number of methylated CpG cites were significantly higher in T carrier than CC genotype in the same generation (P = 0.0418). Our data suggest that MTHFR 677T carrier influences the risk of DNA methylation in gastric mucosa in the long-term outcome of the H. pylori infection.
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PMID:MTHFR 677T carrier influences the methylation status of H. pylori-infected gastric mucosa in older subjects. 1908 89

The global increase in lung cancer burden, together with its poor survival and resistance to classical chemotherapy, underscores the need for identification of critical molecular events involved in lung carcinogenesis. Here, we have applied quantitative profiling of DNA methylation states in a panel of five cancer-associated genes (CDH1, CDKN2A, GSTP1, MTHFR, and RASSF1A) to a large case-control study of lung cancer. Our analyses revealed a high frequency of aberrant hypermethylation of MTHFR, RASSF1A, and CDKN2A in lung tumors as compared with control blood samples, whereas no significant increase in methylation levels of GSTP1 and CDH1 was observed, consistent with the notion that aberrant DNA methylation occurs in a tumor-specific and gene-specific manner. Importantly, we found that tobacco smoking, sex, and alcohol intake had a strong influence on the methylation levels of distinct genes (RASSF1A and MTHFR), whereas folate intake, age, and histologic subtype had no significant influence on methylation states. We observed a strong association between MTHFR hypermethylation in lung cancer and tobacco smoking, whereas methylation levels of CDH1, CDKN2A, GSTP1, and RASSF1A were not associated with smoking, indicating that tobacco smoke targets specific genes for hypermethylation. We also found that methylation levels in RASSF1A, but not the other genes under study, were influenced by sex, with males showing higher levels of methylation. Together, this study identifies aberrant DNA methylation patterns in lung cancer and thus exemplifies the mechanism by which environmental factors may interact with key genes involved in tumor suppression and contribute to lung cancer.
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PMID:Quantitative analysis of DNA methylation profiles in lung cancer identifies aberrant DNA methylation of specific genes and its association with gender and cancer risk factors. 1911 9


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