共查询到20条相似文献，搜索用时 15 毫秒
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Konishi K Watanabe Y Shen L Guo Y Castoro RJ Kondo K Chung W Ahmed S Jelinek J Boumber YA Estecio MR Maegawa S Kondo Y Itoh F Imawari M Hamilton SR Issa JP 《PloS one》2011,6(11):e27889
Background
The contribution of DNA methylation to the metastatic process in colorectal cancers (CRCs) is unclear.Methods
We evaluated the methylation status of 13 genes (MINT1, MINT2, MINT31, MLH1, p16, p14, TIMP3, CDH1, CDH13, THBS1, MGMT, HPP1 and ERα) by bisulfite-pyrosequencing in 79 CRCs comprising 36 CRCs without liver metastasis and 43 CRCs with liver metastasis, including 16 paired primary CRCs and liver metastasis. We also performed methylated CpG island amplification microarrays (MCAM) in three paired primary and metastatic cancers.Results
Methylation of p14, TIMP3 and HPP1 in primary CRCs progressively decreased from absence to presence of liver metastasis (13.1% vs. 4.3%; 14.8% vs. 3.7%; 43.9% vs. 35.8%, respectively) (P<.05). When paired primary and metastatic tumors were compared, only MGMT methylation was significantly higher in metastatic cancers (27.4% vs. 13.4%, P = .013), and this difference was due to an increase in methylation density rather than frequency in the majority of cases. MCAM showed an average 7.4% increase in DNA methylated genes in the metastatic samples. The numbers of differentially hypermethylated genes in the liver metastases increased with increasing time between resection of the primary and resection of the liver metastasis. Bisulfite-pyrosequencing validation in 12 paired samples showed that most of these increases were not conserved, and could be explained by differences in methylation density rather than frequency.Conclusions
Most DNA methylation differences between primary CRCs and matched liver metastasis are due to random variation and an increase in DNA methylation density rather than de-novo inactivation and silencing. Thus, DNA methylation changes occur for the most part before progression to liver metastasis. 相似文献3.
Tränkenschuh W Puls F Christgen M Albat C Heim A Poczkaj J Fleming P Kreipe H Lehmann U 《PloS one》2010,5(10):e13688
Background
Gene silencing due to aberrant DNA methylation is a frequent event in hepatocellular carcinoma (HCC) and also in hepatocellular adenoma (HCA). However, very little is known about epigenetic defects in fibrolamellar carcinoma (FLC), a rare variant of hepatocellular carcinoma that displays distinct clinical and morphological features.Methodology/Principal Findings
We analyzed the methylation status of the APC, CDH1, cyclinD2, GSTπ1, hsa-mir-9-1, hsa-mir-9-2, and RASSF1A gene in a series of 15 FLC and paired normal liver tissue specimens by quantitative high-resolution pyrosequencing. Results were compared with common HCC arising in non-cirrhotic liver (n = 10). Frequent aberrant hypermethylation was found for the cyclinD2 (19%) and the RASSF1A (38%) gene as well as for the microRNA genes mir-9-1 (13%) and mir-9-2 (33%). In contrast to common HCC the APC and CDH1 (E-cadherin) genes were found devoid of any DNA methylation in FLC, whereas the GSTπ1 gene showed comparable DNA methylation in tumor and surrounding tissue at a moderate level. Changes in global DNA methylation level were measured by analyzing methylation status of the highly repetitive LINE-1 sequences. No evidence of global hypomethylation could be found in FLCs, whereas HCCs without cirrhosis showed a significant reduction in global methylation level as described previously.Conclusions
FLCs display frequent and distinct gene-specific hypermethylation in the absence of significant global hypomethylation indicating that these two epigenetic aberrations are induced by different pathways and that full-blown malignancy can develop in the absence of global loss of DNA methylation. Only quantitative DNA methylation detection methodology was able to identify these differences. 相似文献4.
Objective
We previously reported that genetic variants in SORCS1 increase the risk of AD, that over-expression of SorCS1 reduces γ-secretase activity and Aβ levels, and that SorCS1 suppression increases γ-secretase processing of APP and Aβ levels. We now explored the effect of variation in SORCS1 on memory.Methods
We explored associations between SORCS1-SNPs and memory retention in the NIA-LOAD case control dataset (162 cases,670 controls) and a cohort of Caribbean Hispanics (549 cases,544 controls) using single marker and haplotype analyses.Results
Three SNPs in intron 1, were associated with memory retention in the NIA-LOAD dataset or the Caribbean Hispanic dataset (rs10884402(A allele:β = −0.15,p = 0.008), rs7078098(C allele:β = 0.18,p = 0.007) and rs950809(C allele:β = 0.17,p = 0.008)) and all three SNPs were significant in a meta-analysis of both datasets (0.0025.
Background
Epigenetics, particularly DNA methylation, has recently been elucidated as important in gastric cancer (GC) initiation and progression. We investigated the clinical and prognostic importance of whole blood global and site-specific DNA methylation in GC.Methods
Genomic DNA was extracted from the peripheral blood of 105 Omani GC patients at diagnosis. DNA methylation was quantified by pyrosequencing of global DNA and specific gene promoter regions at 5 CpG sites for CDH1, 7 CpG sites for p16, 4 CpG sites for p53, and 3 CpG sites for RUNX3. DNA methylation levels in patients were categorized into low, medium, and high tertiles. Associations between methylation level category and clinicopathological features were evaluated using χ2 tests. Survival analyses were carried out using the Kaplan-Meier method and log rank test. A backward conditional Cox proportional hazards regression model was used to identify independent predictors of survival.Results
Older GC patients had increased methylation levels at specific CpG sites within the CDH1, p53, and RUNX-3 promoters. Male gender was significantly associated with reduced global and increased site-specific DNA methylation levels in CDH1, p16, and p53 promoters. Global DNA low methylation level was associated with better survival on univariate analysis. Patients with high and medium methylation vs. low methylation levels across p16 promoter CpG sites, site 2 in particular, had better survival. Multivariate analysis showed that global DNA hypermethylation was a significant independent predictor of worse survival (hazard ratio (HR) = 2.0, 95% CI: 1.1–3.8; p = 0.02) and high methylation mean values across p16 promoter sites 1–7 were associated with better survival with HR of 0.3 (95% CI, 0.1–0.8; p = 0.02) respectively.Conclusions
Analysis of global and site-specific DNA methylation in peripheral blood by pyrosequencing provides quantitative DNA methylation values that may serve as important prognostic indicators. 相似文献6.
Reduced expression of transcription factor AP-2α is associated with gastric adenocarcinoma prognosis
Wang W Lv L Pan K Zhang Y Zhao JJ Chen JG Chen YB Li YQ Wang QJ He J Chen SP Zhou ZW Xia JC 《PloS one》2011,6(9):e24897
Background
This study aims to investigate the expression and prognostic significance of activator protein 2α (AP-2α) in gastric adenocarcinoma.Methodology/Principal Findings
AP-2α expression was analyzed using real-time quantitative PCR (RT-qPCR), western blotting, and immunohistochemical staining methods on tissue samples from a consecutive series of 481 gastric adenocarcinoma patients who underwent resections between 2003 and 2006. The relationship between AP-2α expression, clinicopathological factors, and patient survival was investigated. RT- qPCR results showed that the expression of AP-2α mRNA was reduced in tumor tissue samples, compared with expression in matched adjacent non-tumor tissue samples (P = 0.009); this finding was confirmed by western blotting analysis (P = 0.012). Immunohistochemical staining data indicated that AP-2α expression was significantly decreased in 196 of 481 (40.7%) gastric adenocarcinoma cases; reduced AP-2α expression was also observed in patients with poorly differentiated tumors (P = 0.001) and total gastric carcinomas (P = 0.002), as well as in patients who underwent palliative tumor resection (P = 0.004). Additionally, reduced expression of AP-2α was more commonly observed in tumors that were staged as T4a/b (P = 0.018), N3 (P = 0.006), and M1 (P = 0.008). Kaplan-Meier survival curves revealed that reduced expression of AP-2α was associated with poor prognosis in gastric adenocarcinoma patients (P<0.001). Multivariate Cox analysis identified AP-2α expression as an independent prognostic factor for overall survival (HR = 1.512, 95% CI = 1.127–2.029, P = 0.006).Conclusions/Significance
Our data suggest that AP-2α plays an important role in tumor progression and that reduced AP-2α expression independently predicts an unfavorable prognosis in gastric adenocarcinoma patients. 相似文献7.
RL Huang CC Chang PH Su YC Chen YP Liao HC Wang YT Yo TK Chao HC Huang CY Lin TY Chu HC Lai 《PloS one》2012,7(7):e41060
Background
Despite of the trend that the application of DNA methylation as a biomarker for cancer detection is promising, clinically applicable genes are few. Therefore, we looked for novel hypermethylated genes for cervical cancer screening.Methods and Findings
At the discovery phase, we analyzed the methylation profiles of human cervical carcinomas and normal cervixes by methylated DNA immunoprecipitation coupled to promoter tiling arrays (MeDIP-on-chip). Methylation-specific PCR (MSP), quantitative MSP and bisulfite sequencing were used to verify the methylation status in cancer tissues and cervical scrapings from patients with different severities. Immunohistochemical staining of a cervical tissue microarray was used to confirm protein expression. We narrowed to three candidate genes: DBC1, PDE8B, and ZNF582; their methylation frequencies in tumors were 93%, 29%, and 100%, respectively. At the pre-validation phase, the methylation frequency of DBC1 and ZNF582 in cervical scraping correlated significantly with disease severity in an independent cohort (n = 330, both P<0.001). For the detection of cervical intraepithelial neoplasia 3 (CIN3) and worse, the area under the receiver operating characteristic curve (AUC) of ZNF582 was 0.82 (95% confidence interval = 0.76–0.87).Conclusions
Our study shows ZNF582 is frequently methylated in CIN3 and worse lesions, and it is demonstrated as a potential biomarker for the molecular screening of cervical cancer. 相似文献8.
Background
Few data have been published on the associations of ferritin with trunk and leg fat depots. We aimed to investigate these associations in a Chinese population.Methodology
Trunk fat mass and leg fat mass were determined in a cross-sectional sample of 1,150 Chinese (479 men and 671 women) aged 50–70 years by dual-energy X-ray absorptiometry scan. Fasting plasma ferritin was measured.Principal Findings
Plasma ferritin was positively correlated with waist circumference, waist-to-hip ratio, total body fat and trunk fat mass, but inversely correlated with leg fat mass in men (r = 0.16, 0.26, 0.19, 0.22 and −0.12, respectively, all P<0.05) and women (r = 0.16, 0.16, 0.08, 0.17 and −0.12, respectively, all P<0.05). Multivariate regression analysis showed that ferritin levels increased with larger trunk fat mass (β = 0.33 ± 0.08 for men and β = 0.21 ± 0.05 for women, both P<0.001) while decreased with larger leg fat mass (β = −0.12 ± 0.09, P = 0.15 for men; and β = −0.14 ± 0.05, P = 0.005 for women). Moreover, plasma ferritin levels decreased with increasing tertile of leg fat mass among each tertile of trunk fat mass.Conclusion
This is the first study to report the opposite associations of trunk and leg fat depots with plasma ferritin levels. 相似文献9.
Li YY 《PloS one》2012,7(4):e35408
Background
The tumor necrosis factor-alpha (TNFα) G308A gene polymorphism has been implicated in susceptibility to essential hypertension (EH), but study results are still controversial.Objective and Methods
The present meta-analysis is performed to investigate the relationship between the TNFα G308A gene polymorphism and EH. Electronic databases were searched and seven separate studies on the association of the TNF α G308A gene polymorphism with EH were analyzed. The meta-analysis involved 1092 EH patients and 1152 controls. The pooled odds ratios (ORs) and their corresponding 95% confidence interval (CI) were calculated by a fixed or random effect model.Results
A significant relationship between the TNFα G308A gene polymorphism and EH was found in an allelic genetic model (OR: 1.45, 95% CI: 1.17 to 1.80, P = 0.0008), a recessive genetic model (OR: 3.181, 95% CI: 1.204 to 8.408, P = 0.02), and a homozygote model (OR: 3.454, 95% CI: 1.286 to 9.278, P = 0.014). No significant association between them was detected in both a dominant genetic model (OR: 1.55, 95% CI: 0.99 to 2.42, P = 0.06) or a heterozygote genetic model (OR: 1.45, 95% CI: 0.90 to 2.33, P = 0.13).Conclusion
The TNFα G308A gene polymorphism is associated with EH susceptibility. 相似文献10.
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Féart C Helmer C Fleury H Béjot Y Ritchie K Amouyel P Schraen-Maschke S Buée L Lambert JC Letenneur L Dartigues JF 《PloS one》2011,6(12):e29480
Objective
Herpes simplex virus (HSV) reactivation has been identified as a possible risk factor for Alzheimer''s disease (AD) and plasma amyloid-beta (Aβ) levels might be considered as possible biomarkers of the risk of AD. The aim of our study was to investigate the association between anti-HSV antibodies and plasma Aβ levels.Methods
The study sample consisted of 1222 subjects (73.9 y in mean) from the Three-City cohort. IgM and IgG anti-HSV antibodies were quantified using an ELISA kit, and plasma levels of Aβ1–40 and Aβ1–42 were measured using an xMAP-based assay technology. Cross-sectional analyses of the associations between anti-HSV antibodies and plasma Aβ levels were performed by multi-linear regression.Results
After adjustment for study center, age, sex, education, and apolipoprotein E-e4 polymorphism, plasma Aβ1–42 and Aβ1–40 levels were specifically inversely associated with anti-HSV IgM levels (β = −20.7, P = 0.001 and β = −92.4, P = 0.007, respectively). In a sub-sample with information on CLU- and CR1-linked SNPs genotyping (n = 754), additional adjustment for CR1 or CLU markers did not modify these associations (adjustment for CR1 rs6656401, β = −25.6, P = 0.002 for Aβ1–42 and β = −132.7, P = 0.002 for Aβ1–40; adjustment for CLU rs2279590, β = −25.6, P = 0.002 for Aβ1–42 and β = −134.8, P = 0.002 for Aβ1–40). No association between the plasma Aβ1–42-to-Aβ1–40 ratio and anti-HSV IgM or IgG were evidenced.Conclusion
High anti-HSV IgM levels, markers of HSV reactivation, are associated with lower plasma Aβ1–40 and Aβ1–42 levels, which suggest a possible involvement of the virus in the alterations of the APP processing and potentially in the pathogenesis of AD in human. 相似文献12.
Patel DC Albrecht C Pavitt D Paul V Pourreyron C Newman SP Godsland IF Valabhji J Johnston DG 《PloS one》2011,6(7):e22142
Objective
Increasing plasma glucose levels are associated with increasing risk of vascular disease. We tested the hypothesis that there is a glycaemia-mediated impairment of reverse cholesterol transport (RCT). We studied the influence of plasma glucose on expression and function of a key mediator in RCT, the ATP binding cassette transporter-A1 (ABCA1) and expression of its regulators, liver X receptor-α (LXRα) and peroxisome proliferator-activated receptor–γ (PPARγ).Methods and Results
Leukocyte ABCA1, LXRα and PPARγ expression was measured by polymerase chain reaction in 63 men with varying degrees of glucose homeostasis. ABCA1 protein concentrations were measured in leukocytes. In a sub-group of 25 men, ABCA1 function was quantified as apolipoprotein-A1-mediated cholesterol efflux from 2–3 week cultured skin fibroblasts. Leukocyte ABCA1 expression correlated negatively with circulating HbA1c and glucose (rho = −0.41, p<0.001; rho = −0.34, p = 0.006 respectively) and was reduced in Type 2 diabetes (T2DM) (p = 0.03). Leukocyte ABCA1 protein was lower in T2DM (p = 0.03) and positively associated with plasma HDL cholesterol (HDL-C) (rho = 0.34, p = 0.02). Apolipoprotein-A1-mediated cholesterol efflux correlated negatively with fasting glucose (rho = −0.50, p = 0.01) and positively with HDL-C (rho = 0.41, p = 0.02). It was reduced in T2DM compared with controls (p = 0.04). These relationships were independent of LXRα and PPARγ expression.Conclusions
ABCA1 expression and protein concentrations in leukocytes, as well as function in cultured skin fibroblasts, are reduced in T2DM. ABCA1 protein concentration and function are associated with HDL-C levels. These findings indicate a glycaemia- related, persistent disruption of a key component of RCT. 相似文献13.
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Tjinta Brinkhuizen Karin van den Hurk Véronique J. L. Winnepenninckx Joep P. de Hoon Ari?nne M. van Marion Jürgen Veeck Manon van Engeland Maurice A. M. van Steensel 《PloS one》2012,7(12)
Background
The genetic background of Basal Cell Carcinoma (BCC) has been studied extensively, while its epigenetic makeup has received comparatively little attention. Epigenetic alterations such as promoter hypermethylation silence tumor suppressor genes (TSG) in several malignancies.Objective
We sought to analyze the promoter methylation status of ten putative (tumor suppressor) genes that are associated with Sonic Hedgehog (SHH), WNT signaling and (hair follicle) tumors in a large series of 112 BCC and 124 healthy control samples by methylation-specific PCR.Results
Gene promoters of SHH (P = 0.016), adenomatous polyposis coli (APC) (P = 0.003), secreted frizzled-related protein 5 (SFRP5) (P = 0.004) and Ras association domain family 1A (RASSF1A) (P = 0.023) showed significantly more methylation in BCC versus normal skin. mRNA levels of these four genes were reduced for APC and SFRP5 in BCC (n = 6) vs normal skin (n = 6). Down regulation of SHH, APC and RASSF1A could be confirmed on protein level as well (P<0.001 for all genes) by immunohistochemical staining. Increased canonical WNT activity was visualized by β-catenin staining, showing nuclear β-catenin in only 28/101 (27.7%) of BCC. Absence of nuclear β-catenin in some samples may be due to high levels of membranous E-cadherin (in 94.1% of the samples).Conclusions
We provide evidence that promoter hypermethylation of key players within the SHH and WNT pathways is frequent in BCC, consistent with their known constitutive activation in BCC. Epigenetic gene silencing putatively contributes to BCC tumorigenesis, indicating new venues for treatment. 相似文献16.
Liao LM Brennan P van Bemmel DM Zaridze D Matveev V Janout V Kollarova H Bencko V Navratilova M Szeszenia-Dabrowska N Mates D Rothman N Boffetta P Chow WH Moore LE 《PloS one》2011,6(11):e27361
Purpose
Leukocyte global DNA methylation levels are currently being considered as biomarkers of cancer susceptibility and have been associated with risk of several cancers. In this study, we aimed to examine the association between long interspersed nuclear elements (LINE-1) methylation levels, as a biomarker of global DNA methylation in blood cell DNA, and renal cell cancer risk.Experimental Design
LINE-1 methylation of bisulfite-converted genomic DNA isolated from leukocytes was quantified by pyrosequencing measured in triplicate, and averaged across 4 CpG sites. A total of 328 RCC cases and 654 controls frequency-matched(2∶1) on age(±5years), sex and study center, from a large case-control study conducted in Central and Eastern Europe were evaluated.Results
LINE-1 methylation levels were significantly higher in RCC cases with a median of 81.97% (interquartile range[IQR]: 80.84–83.47) compared to 81.67% (IQR: 80.35–83.03) among controls (p = 0.003, Wilcoxon). Compared to the lowest LINE-1 methylation quartile(Q1), the adjusted ORs for increasing methylation quartiles were as follows: OR(Q2) = 1.84(1.20−2.81), OR(Q3) = 1.72(1.11−2.65) and OR(Q4) = 2.06(1.34−3.17), with a p-trend = 0.004. The association was stronger among current smokers (p-trend<0.001) than former or never smokers (p-interaction = 0.03). To eliminate the possibility of selection bias among controls, the relationship between LINE-1 methylation and smoking was evaluated and confirmed in a case-only analysis, as well.Conclusions
Higher levels of LINE-1 methylation appear to be positively associated with RCC risk, particularly among current smokers. Further investigations using both post- and pre-diagnostic genomic DNA is warranted to confirm findings and will be necessary to determine whether the observed differences occur prior to, or as a result of carcinogenesis. 相似文献17.
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Sang Hoon Han Seung Up Kim Chang Oh Kim Su Jin Jeong Jun Yong Park Jun Yong Choi Do Young Kim Sang Hoon Ahn Young Goo Song Kwang-Hyub Han June Myung Kim 《PloS one》2013,8(1)
Background and Aims
Liver stiffness measurement (LSM) using transient elastography (Fibroscan®) can identify individuals with potential underlying liver disease. We evaluated the prevalence of abnormal LSM values as assessed using LSM and its predictors in HIV-infected asymptomatic patients receiving combined antiretroviral treatment (cART) without HBV/HCV coinfection.Methods
We prospectively recruited 93 patients who had consistently been undergoing cART for more than 12 months at Severance Hospital in Seoul, Republic of Korea, from June to December 2010. LSM values >5.3 kPa were defined as abnormal.Results
Thirty-nine (41.9%) had abnormal LSM values. On multivariate correlation analysis, the cumulative duration of boosted and unboosted protease inhibitors (PIs) were the independent factors which showed a negative and positive correlation to LSM values, respectively (β = –0.234, P = 0.023 and β = 0.430, P<0.001). In multivariate logistic regression analysis, the cumulative exposure duration of boosted-PIs and γ-glutamyltranspeptidase levels were selected as the independent predictors which showed a negative and positive correlation with abnormal LSM values, respectively (odds ratio [OR], 0.941; 95% confidence interval [CI], 0.889–0.997; P = 0.039 and OR, 1.032; 95% CI, 1.004–1.060; P = 0.023).Conclusion
The high percentage of HIV-infected asymptomatic patients receiving cART without HBV/HCV coinfection had abnormal LSM values. The cumulative exposure duration of boosted-PIs and γ-GT level were independent predictors which showed a negative and positive correlation with abnormal LSM values, respectively. 相似文献20.