共查询到20条相似文献,搜索用时 15 毫秒
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A subgroup of colorectal cancer (CRC) shows non-random accumulation of aberrant DNA methylation, so-called CpG island methylator phenotype (CIMP), which was associated with microsatellite instability and BRAF mutation. As just one group of methylation markers was suitable to extract CIMP+/CIMP-high, and had been commonly used in the "one-panel method", it had been unclear whether another cluster of CRC with DNA methylation accumulation exists in microsatellite-stable CRC. We therefore epigenotyped CRC by a comprehensive approach, that is, the two-way unsupervised hierarchical clustering method using highly quantitative methylation data by a single detection method, MALDI-TOF mass spectrometry, on novel regions selected genome-widely through methylated DNA immunoprecipitation on array analysis. CRC was clearly clustered into three DNA methylation epigenotypes, high-, intermediate- and low-methylation epigenotypes (HME, IME, and LME, respectively). Methylation markers are clustered into two distinct groups: Group-1 methylated specifically in HME and including most reported CIMP-related markers; and Group-2 methylated both in HME and IME. While suitable markers to detect a subgroup of CRC with intermediate methylation and correlation to KRAS mutation have been expected to be developed, our data indicated that a "two-panel method" is necessary to properly classify CRC into three epigenotypes, the first panel to extract HME using Group-1 markers, and the second panel to divide the remaining into IME and LME using Group-2 markers. Here we review and compare our recent study and reported CRC classification methods by DNA methylation information, and propose the use of two panels of methylation markers as CRC classifiers. 相似文献
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Lee S Oh T Chung H Rha S Kim C Moon Y Hoehn BD Jeong D Lee S Kim N Park C Yoo M An S 《International journal of oncology》2012,40(3):889-898
Aberrant methylation of CpG islands in the promoter region of genes is a common epigenetic phenomenon found in early cancers. Therefore conducting genome-scale methylation studies will enhance our understanding of the epigenetic etiology behind carcinogenesis by providing reliable biomarkers for early detection of cancer. To discover novel hypermethylated genes in colorectal cancer by genome-wide search, we first defined a subset of genes epigenetically reactivated in colon cancer cells after treatment with a demethylating agent. Next, we identified another subset of genes with relatively down-regulated expression patterns in colorectal primary tumors when compared with normal appearing-adjacent regions. Among 29?genes obtained by cross-comparison of the two gene-sets, we subsequently selected, through stepwise subtraction processes, two novel genes, GABRA1 and LAMA2, as methylation targets in colorectal cancer. For clinical validation pyrosequencing was used to assess methylation in 134 matched tissue samples from CRC patients. Aberrant methylation at target CpG sites in GABRA1 and LAMA2 was observed with high frequency in tumor tissues (92.5% and 80.6%, respectively), while less frequently in matched tumor-adjacent normal tissues (33.6% for GABRA1 and 13.4% for LAMA2). Methylation levels in primary tumors were not significantly correlated with clinico-pathological features including age, sex, survival and TNM stage. Additionally, we found that ectopic overexpression of GABRA1 in colon cancer cell lines resulted in strong inhibition of cell growth. These results suggest that two novel hypermethylated genes in colorectal cancer, GABRA1 and LAMA2, may have roles in colorectal tumorigenesis and could be potential biomarkers for the screening and the detection of colorectal cancer in clinical practice. 相似文献
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近年来研究表明,表观遗传修饰的DNA甲基化在结直肠癌的发生发展中具有重要的作用。在结直肠癌中普遍存在DNA甲基化,对于肿瘤的早期诊断具有重要的指导意义。因为DNA甲基化的可逆性,可能为肿瘤的治疗提供靶点。从DNA甲基化方面寻找预测结直肠癌药物疗效的分子标志物,有可能成为推动结直肠癌个体化治疗的新方向。 相似文献
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Gao Y Killian K Zhang H Yu K Li QZ Weinstein S Virtamo J Tucker M Taylor P Albanes D Meltzer P Caporaso N 《World journal of gastrointestinal oncology》2012,4(8):193-201
AIM: To explore the association between methylation in leukocyte DNA and colorectal cancer (CRC) risk in male smokers using the α-tocopherol, β-carotene cancer prevention study. METHODS: About 221 incident CRC cases, and 219controls, frequency-matched on age and smoking intensity were included. DNA methylation of 1505 CpG sites selected from 807 genes were evaluated using Il-lumina GoldenGate Methylation Cancer Panel I in prediagnostic blood leukocytes of study subjects. Tertiles of methylation level classified according to the distribution in controls for each CpG site were used to analyze the association between methylation level and CRC risk with logistic regression. The time between blood draw to cancer diagnosis (classifying cases according to latency) was incorporated in further analyses using proportional odds regression. RESULTS: We found that methylation changes of 31 CpG sites were associated with CRC risk at P<0.01 level. Though none of these 31 sites remained statistically significant after Bonferroni correction, the most statistically significant CpG site associated with CRC risk achieved a Pvalue of 1.0×10-4 . The CpG site is located in DSP gene, and the risk estimate was 1.52 (95% CI: 0.91-2.53) and 2.62 (95% CI: 1.65-4.17) for the second and third tertile comparing with the lowest tertile respectively. Taking the latency information into account strengthened some associations, suggesting that the methylation levels of corresponding sites might change over time with tumor progression. CONCLUSION: The results suggest that the methylation level of some genes were associated with cancer susceptibility and some were related to tumor development over time. Further studies are warranted to confirm and refine our results. 相似文献
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Cassinotti E Melson J Liggett T Melnikov A Yi Q Replogle C Mobarhan S Boni L Segato S Levenson V 《International journal of cancer. Journal international du cancer》2012,131(5):1153-1157
Colorectal cancer (CRC) screening rates are currently suboptimal. Blood-based screening could improve rates of earlier detection for CRC and adenomatous colorectal polyps. In this study, we evaluated the feasibility of plasma-based detection of early CRC and adenomatous polyps using array-mediated analysis methylation profiling of 56 genes implicated in carcinogenesis. Methylation of 56 genes in patients with Stages I and II CRC (N=30) and those with adenomatous polyps (N=30) were compared with individuals who underwent colonoscopy and were found to have neither adenomatous changes nor CRC. Composite biomarkers were developed for adenomatous polyps and CRC, and their sensitivity and specificity was estimated using five-fold cross validation. Six promoters (CYCD2, HIC1, PAX 5, RASSF1A, RB1 and SRBC) were selected for the biomarker, which differentiated CRC patients and controls with 84% sensitivity and 68% specificity. Three promoters (HIC1, MDG1 and RASSF1A) were selected for the biomarker, which differentiated patients with adenomatous polyps and controls with sensitivity of 55% and specificity of 65%. Methylation profiling of plasma DNA can detect early CRC with significant accuracy and shows promise as a methodology to develop biomarkers for CRC screening. 相似文献
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The original theory of the multi-step process of colorectal cancer (CRC), suggesting that the disease resulted from the accumulation of mutations in oncogenes and tumor suppressor genes in colonic mucosa cells, has been largely revised following the observation that epigenetic modifications of several genes occur in the average CRC genome. Therefore, the current opinion is that CRCs are the consequence of the accumulation of both mutations and epigenetic modifications of several genes. This mini-review article focuses on DNA methylation biomarkers in CRC. Recent large-scale DNA methylation studies suggest that CRCs can be divided into at least three-four subtypes according to the frequency of DNA methylation and those of mutations in key CRC genes. Despite hundreds of genes might be epigenetically modified in CRC cells, there is interest in the identification of DNA methylation biomarkers to be used for CRC diagnosis, progression, tendency to tissue invasion and metastasis, prognosis, and response to chemotherapeutic agents. Moreover, DNA methylation largely depends on one-carbon metabolism, the metabolic pathway required for the production of S-adenosylmethionine, the major intracellular methylating agent. Complex interactions are emerging among dietary one-carbon nutrients (folates, vitamin B6, vitamin B12, methionine, and others), their metabolic genes, CRC risk, and DNA methylation profiles in CRC. Moreover, active research is also focused on the possible contribution of folic acid dietary fortification during pregnancy and the possible methylation of CRC-related genes in the offspring. 相似文献
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Allelic losses and DNA methylation at DNA mismatch repair loci in sporadic colorectal cancer 总被引:1,自引:0,他引:1
Benachenhou N; Guiral S; Gorska-Flipot I; Michalski R; Labuda D; Sinnett D 《Carcinogenesis》1998,19(11):1925-1929
Normal and tumor DNA samples of 35 patients with sporadic colorectal
carcinoma were analyzed for microsatellite alterations at 12 markers linked
to mismatch repair loci: hMLH1, hMSH2, hMSH3, hMSH6, hPMS1 and hPMS2.
Remarkably, no correlation was observed between the replication error
phenotype (RER+) and allelic losses at these loci. Hemizygous deletions,
seen in 6/35 (17%) informative cases at hMLH1, 4/27 (15%) at hMSH2/hMSH6
and 6/34 (18%) at hMSH3, were rarely found in RER+ tumors. Since mismatch
repair protein components act in molecular complexes of defined
stoichiometry we propose that hemizygous deletion of the corresponding loci
may be involved in colorectal tumorigenesis through defects in cellular
functions other than replication error correction. The analysis of the
methylation status of the promoter region of hMLH1 revealed that
methylation might be an important mechanism of this locus inactivation in
RER+ sporadic colorectal cancer.
相似文献
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目的:寻找和鉴定对顺铂耐药胃癌细胞的异常甲基化基因。方法:我们拟胃癌细胞和耐药细胞为研究对象,采用DNA甲基化芯片,对比分析两种细胞DNA甲基化表达谱差异,结合甲基化特异性PCR(MS-PCR)技术验证获得的异常甲基化基因。结果:利用DNA甲基化谱芯片对胃癌细胞和耐药细胞两个细胞系的基因组DNA甲基化谱进行分析,发现1 095个甲基化差异位点;并筛选出36个高甲基化,14个低甲基化修饰基因。然后通过MS-PCR方法对这50个基因的甲基化修饰在细胞水平上又进行了验证分析,最终筛选出与甲基化谱芯片结果一致的 14种基因,包括11种高甲基化和3种低甲基化修饰基因。结论:胃癌癌细胞发生顺铂耐药时,细胞基因组存在广泛的DNA甲基化修饰改变。 相似文献
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Germline polymorphisms in the one-carbon metabolism pathway and DNA methylation in colorectal cancer
Aditi Hazra Charles S. Fuchs Takako Kawasaki Gregory J. Kirkner David J. Hunter Shuji Ogino 《Cancer causes & control : CCC》2010,21(3):331-345
Dietary intake of one-carbon nutrients (methyl donors) and germline variants in the one-carbon metabolism genes may influence
global DNA methylation level and methylation in promoter CpG islands. In this study, we evaluated the relationship between
single nucleotide polymorphisms (SNPs) in the one-carbon metabolism pathway and DNA methylation status in colorectal cancer.
Utilizing 182 colorectal cancers cases in two prospective cohort studies, we determined the CpG island methylator phenotype
(CIMP) status on eight CIMP-specific promoters and measured LINE-1 methylation level that correlates well with genome-wide
DNA methylation level. We genotyped 23 nonsynonymous SNPs in the one-carbon metabolism genes using buffy coat DNA. Most of
the 23 SNPs in the one-carbon metabolism pathway were not significantly associated with CIMP-high status (≥6/8 methylated
promoters). However, the MTHFR 429 Ala/Ala variant (rs1801131) and the TCN2 259 Arg/Arg variant (rs1801198) were associated with CIMP-high status (MTHFR 429 multivariate odds ratio (MV OR) = 7.56; 95% confidence interval (CI), 1.32–43.3; p trend = 0.10; TCN2 259 Arg/Arg variant MV OR = 3.82; 95% CI, 1.02–14.4; p trend = 0.06). The one-carbon metabolism genotypes were not significantly associated with LINE-1 methylation, although there
were modest differences in mean LINE-1 methylation levels between certain genotypes. Collectively, these exploratory data
provide suggestive evidence for the association of MTHFR
429 Ala/Ala and TCN2 259 Arg/Arg and CIMP status in colorectal cancer. 相似文献
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DNA methylation markers in esophageal cancer: an emerging tool for cancer surveillance and treatment
He Wang Samuel M DeFina Manisha Bajpai Qin Yan Lei Yang Zhongren Zhou 《American journal of cancer research》2021,11(11):5644
Esophageal carcinoma (EC) is one of the most pervasive cancers in the world, with upwards of 500,000 new diagnoses, annually. Despite its prominence, advancements in the detection and treatment of EC have been marginal over the past 30 years and the survival rate continues to stay below 20%. This is due to the uncommonly heterogeneous presentation of EC which presents unprecedented challenges in improving patient survival and quality of care. However, distinct epigenetic alterations to the DNA methylome may provide an avenue to drastically improve the detection and treatment of EC. Specifically, the creation of novel biomarker panels that consist of EC-specific methylation markers have shown promise as a potential alternative to the more invasive, contemporary diagnostic methods. Additionally, growing insight into the biological and clinical properties of EC-specific methylation patterns have opened a window of opportunity for enhanced treatment; of growing interest is the application of “DNMT inhibitors” - a class of drugs which inhibit excessive methylation and have been shown to re-sensitize chemoresistant tumors. Here we provide a comprehensive review of the current advancements in EC DNA methylation to underscore a potential approach to its detection and treatment. 相似文献
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Inge van den Berg Marcel Smid Robert R. J. Coebergh van den Braak Mark A. van de Wiel Carolien H. M. van Deurzen Vanja de Weerd John W. M. Martens Jan N. M. IJzermans Saskia M. Wilting 《Molecular oncology》2021,15(12):3348
Consensus molecular subtypes (CMSs) can guide precision treatment of colorectal cancer (CRC). We aim to identify methylation markers to distinguish between CMS2 and CMS3 in patients with CRC, for which an easy test is currently lacking. To this aim, fresh‐frozen tumor tissue of 239 patients with stage I‐III CRC was analyzed. Methylation profiles were obtained using the Infinium HumanMethylation450 BeadChip. We performed adaptive group‐regularized logistic ridge regression with post hoc group‐weighted elastic net marker selection to build prediction models for classification of CMS2 and CMS3. The Cancer Genome Atlas (TCGA) data were used for validation. Group regularization of the probes was done based on their location either relative to a CpG island or relative to a gene present in the CMS classifier, resulting in two different prediction models and subsequently different marker panels. For both panels, even when using only five markers, accuracies were > 90% in our cohort and in the TCGA validation set. Our methylation marker panel accurately distinguishes between CMS2 and CMS3. This enables development of a targeted assay to provide a robust and clinically relevant classification tool for CRC patients. 相似文献
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Shen Y Takahashi M Byun HM Link A Sharma N Balaguer F Leung HC Boland CR Goel A 《Cancer biology & therapy》2012,13(7):542-552
Accumulating evidence suggests that chemopreventive effects of some dietary polyphenols may in part be mediated by their ability to influence epigenetic mechanisms in cancer cells. Boswellic acids, derived from the plant Boswellia serrata, have long been used for the treatment of various inflammatory diseases due to their potent anti-inflammatory activities. Recent preclinical studies have also suggested that this compound has anti-cancer potential against various malignancies. However, the precise molecular mechanisms underlying their anti-cancer effects remain elusive. Herein, we report that boswellic acids modulate DNA methylation status of several tumor suppressor genes in colorectal cancer (CRC) cells. We treated RKO, SW48 and SW480 CRC cell lines with the active principle present in boswellic acids, acetyl-keto-β-boswellic acid (AKBA). Using genome-wide DNA methylation and gene expression microarray analyses, we discovered that AKBA induced a modest genome-wide demethylation that permitted simultaneous re-activation of the corresponding tumor suppressor genes. The quantitative methylation-specific PCR and RT-PCR validated the gene demethylation and re-expression in several putative tumor suppressor genes including SAMD14 and SMPD3. Furthermore, AKBA inhibited DNMT activity in CRC cells. Taken together, these results lend further support to the growing notion that anti-cancer effect of boswellic acids may in part be due to its ability to demethylate and reactivate methylation-silenced tumor suppressor genes. These results suggest that not only boswellic acid might be a promising epigenetic modulator in the chemoprevention and treatment of CRC, but also provide a rationale for future investigations on the usefulness of such botanicals for epigenetic therapy in other human malignancies. 相似文献
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Arvind K Virmani Jeffrey A Tsou Kimberly D Siegmund Linda Y C Shen Tiffany I Long Peter W Laird Adi F Gazdar Ite A Laird-Offringa 《Cancer epidemiology, biomarkers & prevention》2002,11(3):291-297
Recent analyses of global and gene-specific methylation patterns in cancer cells have suggested that cancers from different organs demonstrate distinct patterns of CpG island hypermethylation. Although certain CpG islands are frequently methylated in many different kinds of cancer, others are methylated only in specific tumor types. Because distinct patterns of CpG island hypermethylation can be seen in tumors from different organs, it seems likely that histological subtypes of cancer within a given organ may exhibit distinct methylation patterns as well. The goal of our study was to determine whether the patterns of CpG island hypermethylation could be used to distinguish between different histological subtypes of lung cancer. We analyzed the methylation status of 23 loci in 91 lung cancer cell lines using the quantitative real-time PCR method MethyLight. Genes PTGS2 (COX2), CALCA, MTHFR, ESR1, MGMT, MYOD1, and APC showed statistically significant differences in the level of CpG island methylation between small cell lung cancer (SCLC) and non-small cell lung cancer cell lines (NSCLC). Hierarchical clustering using a panel consisting of these seven loci yielded two major groups, one of which contained 78% of the SCLC lines. Within this group, a large cluster consisted almost exclusively of SCLC cell lines. Our results show that DNA methylation patterns differ between NSCLC and SCLC cell lines and suggest that these patterns could be developed into a powerful molecular marker to achieve accurate diagnosis of lung cancer. 相似文献
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Szyf M 《Bulletin du cancer》2006,93(9):961-972
Cancer growth and metastasis require the coordinate change in gene expression of different sets of genes. While genetic alterations can account for some of these changes, many of the changes in gene expression observed in cancer are caused by epigenetic modifications. The epigenome consists of the chromatin and its modifications, the "histone code" as well as the pattern of distribution of covalent modifications of cytosines residing in the dinucleotide sequence CG by methylation. The normal pattern of distribution of DNA methylation is altered in cancer. A number of genes are regionally hypermethylated but many parts of the genome are hypomethylated. Hypermethylation of tumor suppressor genes is involved in silencing of strategic genes. DNA hypermethylation has received much attention and a number of clinical trials are underway with different inhibitors of DNA methylating enzymes. It is now becoming clear however that hypomethylation also plays a role in cancer by activating genes required for invasion and metastasis. The potential therapeutic implications of targeting DNA methylation in cancer are discussed. 相似文献