CDH1 Promoter Research Articles

E-Cadherin Deficiency Initiates Gastric Signet-Ring Cell Carcinoma in Mice and Man

The importance of loss of the cell-cell adhesion molecule E-cadherin (encoded by CDH1) to tumor progression is well established. However, CDH1 germ-line mutations predispose to the cancer susceptibility syndrome hereditary diffuse gastric cancer (HDGC), suggesting a role for E-cadherin in tumor initiation. The earliest indications of cancer in the stomachs of CDH1 mutation carriers are microscopic foci of intramucosal signet-ring cell carcinoma (SRCC; designated "eHDGC"). Here, we used N-methyl-N-nitrosourea (MNU) to promote gastric carcinogenesis in wild-type (wt) and cdh1(+/-) mice. MNU induced a variety of gastric tumors; however, intramucosal SRCC developed with an 11 times higher incidence in cdh1(+/-) mice compared with wt mice. The murine SRCC resembled the human eHDGCs in that they were hypoproliferative, lacked nuclear beta-catenin accumulation, and had reduced membrane localization of E-cadherin and its interacting junctional proteins. The down-regulation of E-cadherin in the murine SRCCs confirmed the importance of the second CDH1 hit to the initiation of diffuse gastric cancer. CDH1 promoter hypermethylation has been proposed to be a major second hit in advanced HDGC; however, its contribution to eHDGC was unknown. We thus examined a series of human eHDGC and detected CDH1 promoter methylation in 50% of foci. Promoter methylation was accompanied by reduced wt CDH1 mRNA levels in the foci and had a monoclonal pattern, consistent with an epigenetic initiation of disease. Together, these findings provide compelling evidence for a deficiency in cell-to-cell adhesion being sufficient to initiate diffuse gastric cancer in the absence of hyperproliferation and beta-catenin activation.

CDH1 promoter polymorphism (-347G→GA) is a possibleprognostic factor in sporadic colorectal cancer

To investigate the role of the -347G-->GA polymorphism in the progression of colorectal cancer (CRC). We designed a case-control study based on a population of CRC patients in China and normal healthy controls with no history of tumors or inherited diseases. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses were used to genotype the variants, and immunohistochemical staining was performed to measure the expression of E-cadherin in different allele cases among the CRC patients and normal controls. The GA-allele (G/GA heterozygous and GA/GA homozygous) did not increase the risk of CRC compared with the G-allele (OR=1.232, 95% CI=0.898-1.691). However, the frequencies of the GA-allele were higher in poorly differentiated (P=0.002) and proximal (P=0.019) CRC patients than in normal controls. We also observed that E-cadherin expression was lower in poorly differentiated CRC patients than in well differentiated CRC patients (P=0.001). Furthermore, E-cadherin expression was lower for the GA-allele than for the G-allele (G/G heterozygous) in CRC patients (P=0.018). In contrast, there was no significant difference in E-cadherin expression for the G-allele and GA-allele in normal controls (P=0.292). The -347G-->GA promoter polymorphism in E-cadherin gene is associated with specific CRC features, and may be a prognostic factor rather than a susceptibility factor during the progression of CRC.

Ectopic expression of P-cadherin correlates with promoter hypomethylation early in colorectal carcinogenesis and enhanced intestinal crypt fission in vivo.

P-cadherin is normally expressed in the basal layer of squamous epithelia and absent from the healthy intestine and colon. We have previously shown it to be expressed in all inflamed, hyperplastic, and dysplastic intestinal and colonic mucosa. This study aimed to better understand the mechanisms controlling the expression of P-cadherin and the biological effects of its ectopic presence in the intestine and colon. We investigated the CpG methylation status of the P-cadherin (CDH3) promoter and P-cadherin mRNA and protein expression in cases of familial and sporadic colorectal cancer (CRC). The CDH3 promoter was hypomethylated in colonic aberrant crypt foci, in CRC, and, occasionally, in the normal epithelium adjacent to cancer, demonstrating a potential "field effect" of cancerization. The hypomethylation was also associated with induction of P-cadherin expression in the neoplastic colon (P < 0.0001). We then created transgenic mice that overexpressed P-cadherin specifically in the intestinal and colonic epithelium under the liver fatty acid binding protein promoter. Forced ectopic expression of P-cadherin accompanied by indomethacin-induced inflammation resulted in a 3-fold higher crypt fission rate within the small and large intestines in the homozygous mice compared with the wild-type animals (P < 0.02). We conclude that epigenetic demethylation of the P-cadherin promoter in the human intestine permits its ectopic expression very early in the colorectal adenoma-carcinoma sequence and persists during invasive cancer. Induced P-cadherin expression, especially in mucosal damage, leads to an increased rate of crypt fission, a common feature of clonal expansion in gastrointestinal dysplasia.

Promoter hypermethylation of CDH13 is a common, early event in human esophageal adenocarcinogenesis and correlates with clinical risk factors

Although the CDH13 gene has been shown to undergo epigenetic silencing by promoter methylation in many types of tumors, hypermethylation of this gene in Barrett's-associated esophageal adenocarcinogenesis has not been studied. Two hundred fifty-nine human esophageal tissues were therefore examined for CDH13 promoter hypermethylation by real-time methylation-specific PCR. CDH13 hypermethylation showed discriminative receiver-operator characteristic curve profiles, sharply demarcating esophageal adenocarcinoma (EAC) from esophageal squamous cell carcinoma (ESCC) and normal esophagus (NE) (p < 0.0001). CDH13 normalized methylation values (NMV) were significantly higher in Barrett's esophagus (BE), dysplastic BE (D) and EAC than in NE (p < 0.0000001). CDH13 hypermethylation frequency was 0% in NE but increased early during neoplastic progression, rising to 70% in BE, 77.5% in D and 76.1% in EAC. Both CDH13 hypermethylation frequency and its mean NMV were significantly higher in BE with than without accompanying EAC. In contrast, only 5 (19.2%) of 26 ESCCs exhibited CDH13 hypermethylation. Furthermore, both CDH13 hypermethylation frequency and its mean NMV were significantly higher in EAC than in ESCC, as well as in BE or D vs. ESCC. Interestingly, mean CDH13 NMV was significantly lower in short-segment than in long-segment BE, a known clinical risk factor for neoplastic progression. Similarly, BE segment length was significantly lower in specimens with unmethylated than with methylated CDH13 promoters. 5-aza-2'-deoxycytidine treatment of OE33 EAC and KYSE220 ESCC cells reduced CDH13 methylation and increased CDH13 mRNA expression. These findings suggest that hypermethylation of CDH13 is a common, tissue-specific event in human EAC, occurs early during BE-associated neoplastic progression, and correlates with known clinical neoplastic progression risk factors.

Polycomb Complex 2 Is Required for E-cadherin Repression by the Snail1 Transcription Factor

The transcriptional factor Snail1 is a repressor of E-cadherin (CDH1) gene expression essential for triggering epithelial-mesenchymal transition. Snail1 represses CDH1, directly binding its promoter and inducing the synthesis of the Zeb1 repressor. In this article, we show that repression of CDH1 by Snail1, but not by Zeb1, is dependent on the activity of Polycomb repressive complex 2 (PRC2). Embryonic stem (ES) cells null for Suz12, one of the components of PRC2, show higher levels of Cdh1 mRNA than control ES cells. In tumor cells, interference of PRC2 activity prevents the ability of Snail1 to downregulate CDH1 and partially derepresses CDH1. Chromatin immunoprecipitation assays demonstrated that Snail1 increases the binding of Suz12 to the CDH1 promoter and the trimethylation of lysine 27 in histone H3. Moreover, Snail1 interacts with Suz12 and Ezh2, as shown by coimmunoprecipitation experiments. In conclusion, these results demonstrate that Snail1 recruits PRC2 to the CDH1 promoter and requires the activity of this complex to repress E-cadherin expression.

Epigenetic alterations of CDH1 and APC genes: Relationship with activation of Wnt/β-catenin Pathway in invasive ductal carcinoma of breast

Activation of canonical Wnt/β-catenin pathway in Invasive Ductal Carcinoma of Breast (IDCs) was recently reported from our laboratory. Herein, we analyzed promoter methylation status of CDH1 and Adenomatous polyposis coli (APC) genes in 50 IDCs and correlated with expression of E-cadherin (E-CD) and APC proteins and with activation of oncogenic Wnt/β-catenin signaling pathway components, Dvl, β-catenin and CyclinD1. Further, Wnt/β-catenin driven epithelial mesenchymal transition (EMT) was investigated by correlating the expression of Dvl, β-catenin and CyclinD1 with vimentin expression in these IDCs. Promoter hypermethylation was observed in 25/50 (50%) IDCs for CDH1 and in 11/50 (22%) tumors for APC, associated with loss of expression of E-CD and APC proteins; concordant hypermethylation of these genes was observed in paired patients’ sera. Further, 57% of tumors harboring CDH1 methylation and 50% tumors harboring the methylated APC gene showed nuclear localization of β-catenin, suggesting activation of the canonical Wnt/β-catenin pathway. Our study demonstrates significant association between vimentin expression and nuclear β-catenin ( p = 0.001; Odds ratio (OR) = 25.6) and Dvl ( p = 0.023; OR = 8.0), suggesting that EMT may be driven by Wnt/β-catenin activation in IDCs. In conclusion, we demonstrate correlation of CDH1 and APC promoter methylation with loss of E-CD and APC proteins and with activation of Wnt/β-catenin signaling pathway. Association of nuclear Dvl and β-catenin with vimentin expression suggests the importance of Wnt/β-catenin pathway driven EMT in IDCs. The concordance between CDH1 and APC methylation in IDCs and paired circulating DNA underscores the utility of serum DNA as a non-invasive tool for methylation analysis in IDC patients.

A polymorphism in the 3′UTR region of E-cadherin associates with recurrence of breast cancer

22101 Background: Maintenance of epithelial integrity plays a major role in tumor suppression but may also be important in metastasis and recurrence of cancer. Loss of E-cadherin (CDH1) is implicated in invasive lobular carcinomas of the breast. Furthermore, a polymorphic variant in the CDH1 promoter has been reported in association studies. We investigated the association of polymorphic variants in CDH1 with recurrence of breast cancer. Methods: TaqMan allelic discrimination assays were performed on genomic DNA prepared from whole blood of breast cancer patients. Genotyping was determined for several loci in CDH1 and were linked to clinical information. Results: CDH1 genotypes for the 3’UTR Ex16+246C>T polymorphism are in Hardy-Weinberg equilibrium with frequencies of: CC 69%, CT 27%, and TT 4%. Population-specific genotype frequencies were observed. There were no frequency differences between invasive ductal and invasive lobular carcinomas, but a trend toward a 4-year earlier age of onset of the latter associated with the low frequency allele. Seventeen percent of women in this cohort recurred, nearly half representing progesterone receptor-negative (PgR−) and half progesterone receptor-positive (PgR+) breast cancers. The recurrence rate for each genotype was 14.3%, 26%, and 7.1% for CC, CT, and TT genotypes, respectively. In women without recurrence, the genotype distribution was the same for PgR+ and PgR− disease. However, in those that recur, women with the CC genotype were more likely to be PgR− OR 2.32 CI [1.13–4.77] with a p value=0.023. The converse could not be evaluated due to small numbers. Conclusions: A polymorphic variant in the 3’UTR region of CDH1 is associated with recurrence of breast cancer. This association is strongest in recurrence of progesterone receptor-negative breast cancers. Recurrence in this SNP association study may reflect the effect of progesterone on proteins in adherence junctions or desmosomes or the role of CDH1 in the beta-catenin pathway. Support was from the New Jersey Commission on Cancer Research. No significant financial relationships to disclose.

Promoter Methylation Analysis of SIRT3, SMARCA5, HTERT and CDH1 Genes in Aging and Alzheimer's Disease

Longevity related genes were investigated concerning promoter methylation. SIRT3, SMARCA5, HTERT and CDH1 promoters were analyzed in peripheral blood in relation to gender, age and Alzheimer's disease (AD). Methylation Specific PCR assay (MSP) was used. There were no significant differences in methylation frequencies of SIRT3, SMARCA5 and CDH1 among young, elderly and AD groups (p> 0.05), showing no association with aging or AD. On the other hand, HTERT methylation frequency was associated with the aging process, in that AD patients differed from elderly controls (p=0.0086), probably due to telomere and immune dysfunctions involved in AD pathogenesis.

Endogastric capsule for E-cadherin gene (CDH1) promoter hypermethylation assessment in DNA from gastric juice of diffuse gastric cancer patients

BackgroundWe investigated whether an endogastric capsule (EC) may be a valuable tool for collecting DNA from exfoliated cells from the gastric mucosa and for carrying out an analysis of promoter methylation status of the E-cadherin (CDH1) gene in poorly differentiated, diffuse gastric cancer (DGC). Material and methodsConsecutive patients with a confirmed diagnosis of poorly differentiated DGC underwent collection of gastric juice by EC. Subjects without cancer and premalignant lesions were also accrued as controls. The samples of gastric juice were processed for DNA isolation and amplification. Then they were used for analysis of CDH1 promoter hypermethylation. ResultsThe procedure successfully allowed the analysis of CDH1 promoter hypermethylation in 20 patients and 14 controls. This pilot study showed feasibility of the procedure and a significantly different CDH1 promoter hypermethylation status between DGC patients and controls was detected. ConclusionsThe EC may represent an innovative and noninvasive tool for the analysis of a specific epigenetic change in DGC patients. Our findings deserve additional studies as this method may represent a cost-effective tool for early detection of sporadic as well as hereditary DGC in CDH1 germline mutations carriers.

P-cadherin is a p63 target gene with a crucial role in the developing human limb bud and hair follicle

P-cadherin is a member of the classical cadherin family that forms the transmembrane core of adherens junctions. Recently, mutations in the P-cadherin gene (CDH3) have been shown to cause two inherited diseases in humans: hypotrichosis with juvenile macular dystrophy (HJMD) and ectodermal dysplasia, ectrodactyly, macular dystrophy (EEM syndrome). The common features of both diseases are sparse hair and macular dystrophy of the retina, while only EEM syndrome shows the additional finding of split hand/foot malformation (SHFM). We identified five consanguineous Pakistani families with either HJMD or EEM syndrome, and detected pathogenic mutations in the CDH3 gene of all five families. In order to define the role of P-cadherin in hair follicle and limb development, we performed expression studies on P-cadherin in the mouse embryo, and demonstrated the predominant expression of P-cadherin not only in the hair follicle placode, but also at the apical ectodermal ridge (AER) of the limb bud. Based on the evidence that mutations in the p63 gene also result in hypotrichosis and SHFM, and that the expression patterns of p63 and P-cadherin overlap in the hair follicle placode and AER, we postulated that CDH3 could be a direct transcriptional target gene of p63. We performed promoter assays and ChIP, which revealed that p63 directly interacts with two distinct regions of the CDH3 promoter. We conclude that P-cadherin is a newly defined transcriptional target gene of p63, with a crucial role in hair follicle morphogenesis as well as the AER during limb bud outgrowth in humans, whereas it is not required for either in mice.

DNA methyltransferase 1 knockdown induces silenced CDH1 gene reexpression by demethylation of methylated CpG in hepatocellular carcinoma cell line SMMC-7721

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related mortality in the world; however, the molecular mechanisms leading to hepatocyte transformation, especially in epigenetic mechanisms (such as DNA methylation) are still poorly understood. DNA methyltransferase 1 (DNMT1) is the predominant maintenance methyltransferase gene required to maintain DNA methylation patterns in mammalian cells. To explore the role of DNMT1 in the regulation of expression of tumor-related genes in human HCC cells via DNA methylation of the regulatory CpG islands, we stably transfected expression constructs containing small interfering RNA (siRNA) of DNMT1 into the human HCC cell line, SMMC-7721. RNA interference knocked down specific DNMT1 protein expression, resulting in the demethylated promoter of CDH1 and the reexpression of CDH1 in 7721-pMT1. By contrast, promoter methylation and lack of gene expression were maintained when the cell lines had control constructs. Knock down of DNMT1 expression by siRNA induced the promoter of CDH1 demethylation and upregulated CDH1 transcription. High-density oligonucleotide gene expression microarrays were used to examine the effects of DNMT1 knock down on human HCC cells (SMMC-7721); these showed that a number of genes were induced in the DNMT1 knock down cell lines, including some important tumor-related genes such as PDCD4, DCN and PTGES except CDH1. Only approximately 78% of the induced genes have CpG islands within their 5' regions, suggesting that certain genes activated by DNMT1 siRNA might not have resulted from the direct inhibition of promoter methylation. In hepatocellular carcinoma, DNMT1 is necessary to maintain the methylation of CpG islands in certain tumor-related genes.

Snail Family Transcription Factors Are Implicated in Thyroid Carcinogenesis

E-Cadherin (CDH1) expression is reduced in thyroid carcinomas by primarily unknown mechanisms. In several tissues, SNAIL (SNAI1) and SLUG (SNAI2) induce epithelial-mesenchymal transition by altering target gene transcription, including CDH1 repression, but these transcription factors have not been studied in thyroid carcinoma. Recently, our group has provided direct evidence that ectopic SNAI1 expression induces epithelial and mesenchymal mouse tumors. SNAI1, SNAI2, and CDH1 expression were analyzed in thyroid-derived cell lines and samples of human follicular and papillary thyroid carcinoma by reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry. The effect of SNAI1 expression on CDH1 transcription was analyzed by reverse transcriptase-polymerase chain reaction and Western blotting in ori-3 cells. Thyroid carcinoma development was analyzed in CombitTA-Snail mice, in which SNAI1 levels are up-regulated. SNAI1 and SNAI2 were not expressed in cells derived from normal thyroid tissue, or in normal human thyroid samples, but were highly expressed in cell lines derived from thyroid carcinomas, in human thyroid carcinoma samples, and their metastases. SNAI1 expression in ori-3 cells repressed CDH1 transcription. Combi-TA mice developed papillary thyroid carcinomas, the incidence of which was increased by concomitant radiotherapy. In conclusion, SNAI1 and SNAI2 are ectopically expressed in thyroid carcinomas, and aberrant expression in mice is associated with papillary carcinoma development.

317 POSTER APC, CDH1 and CTNN1B promoter CpG islands methylation patterns during ductal breast carcinoma progression

Angiogenic and lymphangiogenic factors (ALFs) may play an important role in inflammatory bowel disease (IBD). Our aims were to evaluate levels of ALFs in serum and the colonic mucosa culture supernatant (MCS) of patients with active and quiescent IBD and healthy subjects and to correlate them with the endoscopic, clinical and histological activity and with acute-phase reactants.This is a prospective study of 28 controls and 72 IBD patients. Serum and MCS concentration of VEGFA, VEGFC, VEGFD, VEGFR1, VEGFR2, VEGFR3, PlGF, Ang1, Ang2 and Tie2 were measured by ELISA. Activity was established by specific indexes (CDAI, Mayo score, SES-CD, D'Haens scale and Riley index). Acute-phase reactants were routinely measured.MCS levels of all ALFs except VEGFR3 were higher in patients with endoscopic (p < 0.05), clinical (p < 0.05) and histological (p < 0.01) activity than in those without it. In serum, VEGFA, VEGFC and Ang1 and VEGFA and Ang1 levels were lower in patients in remission than in patients with clinical and histological activity, respectively (p < 0.05). There was a correlation between serum and MCS concentrations for VEGFD, VEGFR3, PlGF and Tie2 (r = 0.25, r = 0.48, r = -0.45 and r = 0.36; p < 0.05). Ang2 in MCS was the best predictor for the diagnosis of endoscopic, histological and clinical activity (area under ROC curve > 0.8).MCS determination suggests a local increase in ALFs that correlates with IBD activity. Although the correlation between ALFs in serum and MCS was not good, the study of some of these factors as possible targets of new drugs for IBD constitutes a key new line of research.

Quantitative promoter methylation analysis of multiple cancer-related genes in renal cell tumors

BackgroundAberrant promoter hypermethylation of cancer-associated genes occurs frequently during carcinogenesis and may serve as a cancer biomarker. In this study we aimed at defining a quantitative gene promoter methylation panel that might identify the most prevalent types of renal cell tumors.MethodsA panel of 18 gene promoters was assessed by quantitative methylation-specific PCR (QMSP) in 85 primarily resected renal tumors representing the four major histologic subtypes (52 clear cell (ccRCC), 13 papillary (pRCC), 10 chromophobe (chRCC), and 10 oncocytomas) and 62 paired normal tissue samples. After genomic DNA isolation and sodium bisulfite modification, methylation levels were determined and correlated with standard clinicopathological parameters.ResultsSignificant differences in methylation levels among the four subtypes of renal tumors were found for CDH1 (p = 0.0007), PTGS2 (p = 0.002), and RASSF1A (p = 0.0001). CDH1 hypermethylation levels were significantly higher in ccRCC compared to chRCC and oncocytoma (p = 0.00016 and p = 0.0034, respectively), whereas PTGS2 methylation levels were significantly higher in ccRCC compared to pRCC (p = 0.004). RASSF1A methylation levels were significantly higher in pRCC than in normal tissue (p = 0.035). In pRCC, CDH1 and RASSF1A methylation levels were inversely correlated with tumor stage (p = 0.031) and nuclear grade (p = 0.022), respectively.ConclusionThe major subtypes of renal epithelial neoplasms display differential aberrant CDH1, PTGS2, and RASSF1A promoter methylation levels. This gene panel might contribute to a more accurate discrimination among common renal tumors, improving preoperative assessment and therapeutic decision-making in patients harboring suspicious renal masses.

Single Nucleotide Polymorphisms in the Promoter Region of the E-cadherin Gene in Gastric Cancer: Case-Control Study in a Young Mexican Population

Gastric cancer has a tendency to present at early age in the Mexican population, and it is frequently associated with a family history. A polymorphism at position -160 at the CDH1 promoter region has been reported to lead to transcriptional downregulation of the gene in vitro, with possible increase in the risk of gastric cancer. We evaluated the role of the -160A allele in the risk of gastric cancer in a young Mexican population. Peripheral blood sample of Mexican patients younger than 45 years old with diagnosis of diffuse gastric cancer were obtained. We performed DNA extraction and analyzed the frequencies of -160 promoter polymorphism of E-cadherin gene by polymerase chain reaction-single strand conformational polymorphism. These frequencies were compared with those of healthy controls. The chi2 test for association was used to test differences of the genotype frequencies between normal controls and patients with gastric cancer. Findings were considered significant at P < .05. The frequency of the -160 A allele was significantly higher (P = .002) in 39 patients with diffuse gastric cancer compared with 78 matched controls. The odds ratio associated with the A-allele was 1.98 for C/A heterozygotes (95% CI 1.01-3.98) and 6.5 for A/A homozygotes (95% CI 2.1-19.6). We found an increased risk of diffuse gastric cancer according to family history, independent of the expression of the polymorphism. The -160 C/A polymorphism of the E-cadherin has a direct effect on the risk of diffuse gastric cancer at young age in Mexican population.

Promoter hypermethylation ofCDH1,FHIT,MTAPandPLAGL1in gastric adenocarcinoma in individuals from Northern Brazil

To evaluate the methylation status of CDH1, FHIT, MTAP and PLAGL1 promoters and the association of these findings with clinico-pathological characteristics. Methylation-specific PCR (MSP) assay was performed in 13 nonneoplastic gastric adenocarcinoma, 30 intestinal-type gastric adenocarcinoma and 35 diffuse-type gastric adenocarcinoma samples from individuals in Northern Brazil. Statistical analyses were performed using the chi-square or Fisher's exact test to assess associations between methylation status and clinico-pathological characteristics. Hypermethylation frequencies of CDH1, FHIT, MTAP and PLAGL1 promoter were 98.7%, 53.9%, 23.1% and 29.5%, respectively. Hypermethylation of three or four genes revealed a significant association with diffuse-type gastric cancer compared with nonneoplastic cancer. A higher hypermethylation frequency was significantly associated with H pylori infection in gastric cancers, especially with diffuse-type. Cancer samples without lymph node metastasis showed a higher FHIT hypermethylation frequency. MTAP hypermethylation was associated with H pylori in gastric cancer samples, as well as with diffuse-type compared with intestinal-type. In diffuse-type, MTAP hypermethylation was associated with female gender. Our findings show differential gene methylation in tumoral tissue, which allows us to conclude that hypermethylation is associated with gastric carcinogenesis. MTAP promoter hypermethylation can be characterized as a marker of diffuse-type gastric cancer, especially in women and may help in diagnosis, prognosis and therapies. The H pylori infectious agent was present in 44.9% of the samples. This infection may be correlated with the carcinogenic process through the gene promoter hypermethylation, especially the MTAP promoter in diffuse-type. A higher H pylori infection in diffuse-type may be due to greater genetic predisposition.

Polymorphisms in the E-cadherin ( CDH1) gene promoter and the risk of bladder cancer

Aim E-cadherin plays a role in carcinogenesis. For two genetic polymorphisms in the gene ( CDH1) promoter, a reduced transcription has been reported: a C/A single nucleotide polymorphism (SNP) and a G/GA SNP at −160 bp and −347 bp, respectively, upstream of the transcriptional start site. We studied the association between both polymorphisms and the risk of bladder cancer. Methods One hundred and ninety-seven patients with bladder cancer and 344 population controls were genotyped and haplotyped for both SNPs. Results A borderline significantly increased risk for bladder cancer was found for A allele carriers (OR 1.36; 95% CI: 0.96–1.94). We did not find any association between the –347 G/GA SNP and bladder cancer. Haplotype analyses did not yield much stronger associations with bladder cancer than the –160 C/A genotype analyses. Conclusion This study supports earlier suggestions that the –160 C/A SNP in the CDH1 promoter is a risk factor for bladder cancer.

Aberrant methylation of CDH13 gene in nasopharyngeal carcinoma could serve as a potential diagnostic biomarker

CDH13 encodes a cell adhesion molecule, H-cadherin. In this study, we examined CDH13 methylation in nasopharyngeal carcinoma (NPC). Methylation specific PCR results showed that CDH13 was methylated in 20% (1/5) NPC cell lines, 100% (2/2) NPC xenografts and 89.7% (52/58) of the NPC primary tumors, while only methylated in 10% (1/10) normal nasopharyngeal epithelia (P<0.05). CDH13 expression in NPC cell lines and NPC xenografts analyzed by RT-PCR showed that expressions of CDH13 were reversely correlated with their methylation status. In CDH13-silenced cell line, demethylating agent 5-aza-deoxycytidine could dramatically restore CDH13 expression. Taken together, CDH13 promoter is aberrantly methylated in NPC both in vitro and in vivo, and promoter methylation plays a pivotal role in the silencing of H-cadherin expression. Furthermore, the high sensitivity (81%) and specificity (0% false positives) of detecting CDH13 methylation from nasopharyngeal swabs suggest it could be utilized as a tool for early diagnosis.

Combined DNA Methyltransferase and Histone Deacetylase Inhibition in the Treatment of Myeloid Neoplasms

Optimal reexpression of most genes silenced through promoter methylation requires the sequential application of DNA methyltransferase inhibitors followed by histone deacetylase inhibitors in tumor cell cultures. Patients with myelodysplastic syndrome or acute myeloid leukemia (AML) were treated with the methyltransferase inhibitor 5-azacitidine (aza-CR) followed by the histone deacetylase inhibitor sodium phenylbutyrate. Major responses associated with cytogenetic complete response developed in patients receiving prolonged dosing schedules of aza-CR. Bisulfite sequencing of the p15 promoter in marrow DNA during the first cycle of treatment showed heterogeneous allelic demethylation in three responding patients, suggesting ongoing demethylation within the tumor clone, but no demethylation in two nonresponders. Six of six responding patients with pretreatment methylation of p15 or CDH-1 promoters reversed methylation during the first cycle of therapy (methylation-specific PCR), whereas none of six nonresponders showed any demethylation. Gene demethylation correlated with the area under the aza-CR plasma concentration-time curve. Administration of both drugs was associated with induction of acetylation of histones H3 and H4. This study provides the first demonstration that molecular mechanisms responsible for responses to DNA methyltransferase/histone deacetylase inhibitor combinations may include reversal of aberrant epigenetic gene silencing. The promising percentage of major hematologic responses justifies the testing of such combinations in prospective randomized trials.

Methylation study of CDH1, P16, APC and MLH1 genes promoter along multistep gastric carcinogenesis

Methylation study of CDH1, P16, APC and MLH1 genes promoter along multistep gastric carcinogenesis