http://www.geneimprint.com/site/hot-off-the-press Daily listing of the most recent articles in epigenetics and imprinting, collected from the PubMed database. en-us Wed, 08 Sep 2010 18:25:26 EDT Wed, 08 Sep 2010 18:25:26 EDT jirtle@radonc.duke.edu james001@jirtle.com Nair SS, Coolen MW, Stirzaker C, Song JZ, Statham AL, Strbenac D, Robinson MD, Clark SJ
Epigenetics (Jan 2011)

DNA methylation primarily occurs at CpG dinucleotides in mammals and is a common epigenetic mark that plays a critical role in the regulation of gene expression. Profiling DNA methylation patterns across the genome is vital to understand DNA methylation changes that occur during development and in disease phenotype. In this study, we compared two commonly used approaches to enrich for methylated DNA regions of the genome, namely methyl- DNA immunoprecipitation (MeDIP) that is based on enrichment with antibodies specific for 5'-methylcytosine (5MeC) and capture of methylated DNA using a methyl-CpG binding domain-based (MBD) protein to discover differentially methylated regions (DMRs) in cancer. The enriched methylated DNA fractions were interrogated on Affymetrix promoter tiling arrays and differentially methylated regions were identified. A detailed validation study of 42 regions was performed using Sequenom MassCLEAVE technique. This detailed analysis revealed that both enrichment techniques are sensitive for detecting DMRs and preferentially identified different CpG rich regions of the prostate cancer genome, with MeDIP commonly enriching for methylated regions with a low CpG density, while MBD capture favors regions of higher CpG density and identifies the greatest proportion of CpG islands. This is the first detailed validation report comparing different methylated DNA enrichment techniques for identifying regions of differential DNA methylation. Our study highlights the importance of understanding the nuances of the methods used for DNA genome-wide methylation analyses so that accurate interpretation of the biology is not overlooked.]]> Mon, 06 Sep 2010 00:00:00 EDT Morales JC, Ruiz-Magaña MJ, Carranza D, Ortiz-Ferrón G, Ruiz-Ruiz C
Cancer Lett (Nov 2010)

Epigenetic modifications commonly associated with tumor development, such as histone deacetylation, may influence the resistance of some tumor cells to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) by regulating gene transcription of components of the TRAIL signalling pathway. In the present study we have analyzed the effect of six different histone deacetylase inhibitors (HDACi), belonging to the four classic structural families, on TRAIL-induced apoptosis in leukemic T cell lines. Non-toxic and functional doses of all HDACi but apicidin, similarly sensitized different leukemic T cell lines to TRAIL-induced apoptosis, while they showed no effect on the resistance of normal T lymphocytes. Sensitizing doses of vorinostat, valproic acid, sodium butyrate and MS-275 regulated the expression of TRAIL-R2, c-FLIP and Apaf-1 in leukemic cells while TSA modulated only the expression of Apaf-1. The synergistic effect of all HDACi and TRAIL was inhibited in Bcl-2-overexpressing leukemic T cells. Thus, different HDACi may affect the expression of different TRAIL-related genes, but regulation of the mitochondrial pathway seems to be essential for the TRAIL sensitizing effect of HDACi in leukemic T cells. Overall, HDACi represent a promising and safe strategy in combination with TRAIL for treatment of T-cell leukaemia.]]> Mon, 06 Sep 2010 00:00:00 EDT Bullwinkel J, Lüdemann A, Debarry J, Singh PB
Epigenetics (Jan 2011)

Using an in vitro model for the differentiation of human blood-derived monocytes into dendritic cells (DCs), we have undertaken an investigation of epigenetic changes that take place at CD14 and CD209 (DC-SIGN) genes that encode cell surface antigens that are crucial for the function of monocytes and DCs, respectively. Upon differentiation the cell surface expression of CD14 is lost, whilst CD209 expression is increased. These reciprocal changes are associated with the loss of epigenetic markers of "activation" at the CD14 locus, but the acquisition of the same at the CD209 locus. There is little change in "repressive" histone marks and CpG methylation at the CD14 locus. By contrast there are changes in both the "repressive" histone marks and CpG methylation at the CD209 locus. In particular, two CpG dinucleotides, designated CpG2 and CpG3, show a marked demethylation at the CD209 promoter upon differentiation. These data provide insight into the epigenetic demands that are necessary to effect the reciprocal changes in expression of the CD14 and CD209 genes upon terminal differentiation of monocytes into DCs. For repression of the active CD14 gene the loss of "activation" histone modifications is likely necessary and sufficient for silencing. By contrast the activation of the silent CD209 gene appears to require an acquisition of "active" histone modifications and concomitant loss of both "repressive" histone marks and CpG methylation.]]> Mon, 06 Sep 2010 00:00:00 EDT Lim S, Metzger E, Schüle R, Kirfel J, Buettner R
Int J Cancer (Nov 2010)

Cancer is traditionally viewed as a primarily genetic disorder. However, it is now increasingly apparent that epigenetic abnormalities play a fundamental role in cancer development. Aberrant expression of histone-modifying enzymes has been implicated in the course of tumor initiation and progression. The discovery of a large number of histone demethylases suggests an important role for dynamic regulation of histone methylation in biological processes. The observation that overexpression, amplification or mutations of several histone demethylases have been found in many types of tumors, raise the possibility of using these enzymes as diagnostic tools as well as pave a way for the discovery of novel therapeutic targets and treatment modalities. Here, we review the current knowledge of the potential role of H3K4, H3K9 and H3K27 histone demethylases in tumorigenesis.]]> Thu, 02 Sep 2010 00:00:00 EDT Oh SS, Chang SC, Cai L, Cordon-Cardo C, Ding BG, Greenland S, He N, Jiang Q, Kheifets L, Le A, Lee YC, Liu S, Lu ML, Mao JT, Morgenstern H, Mu LN, Pantuck A, Papp JC, Park SL, Rao JY, Reuter VE, Tashkin DP, Wang H, You NC, Yu SZ, Zhao JK, Belldegrun A, Zhang ZF
Int J Cancer (Nov 2010)

Tobacco smoke and its metabolites are carcinogens that increase tissue oxidative stress and induce target tissue inflammation. We hypothesized that genetic variation of inflammatory pathway genes plays a role in tobacco-related carcinogenesis and is modified by tobacco smoking. We evaluated the association of 12 single nucleotide polymorphisms of 8 inflammation-related genes with tobacco-related cancers (lung, oropharynx, larynx, esophagus, stomach, liver, bladder, and kidney) using 3 case-control studies from: Los Angeles (population-based; 611 lung and 553 upper aero-digestive tract cancer cases and 1,040 controls), Taixing, China (population-based; 218 esophagus, 206 stomach, 204 liver cancer cases, and 415 controls), and Memorial Sloan-Kettering Cancer Center (hospital-based; 227 bladder cancer cases and 211 controls). After adjusting for age, education, ethnicity, gender, and tobacco smoking, IL10 rs1800871 was inversely associated with oropharyngeal cancer (CT+TT vs. CC adjusted odds ratio [aOR]: 0.69, 95% confidence interval [CI]: 0.50-0.95), and was positively associated with lung cancer among never smokers (TT vs. CT+CC aOR: 2.5, 95% CI: 1.3-5.1) and inversely with oropharyngeal cancer among ever smokers (CT+TT vs. CC aOR: 0.63, 95% CI: 0.41-0.95). Among all pooled never smokers (588 cases and 816 controls), TNF rs1799964 was inversely associated with smoking-related cancer (CC vs. CT+TT aOR: 0.36, 95% CI: 0.17-0.77). Bayesian correction for multiple comparisons suggests that chance is unlikely to explain our findings (although epigenetic mechanisms may be in effect), which support our hypotheses, suggesting that IL10 rs1800871 is a susceptibility marker for oropharyngeal and lung cancers, and that TNF rs1799964 is associated with smoking-related cancers among never smokers.]]> Thu, 02 Sep 2010 00:00:00 EDT An B, Kondo Y, Okamoto Y, Shinjo K, Kanemitsu Y, Komori K, Hirai T, Sawaki A, Tajika M, Nakamura T, Yamao K, Yatabe Y, Fujii M, Murakami H, Osada H, Tani T, Matsuo K, Shen L, Issa JP, Sekido Y
Int J Cancer (Nov 2010)

Aberrant DNA methylation is involved in colon carcinogenesis. Although the CpG island methylator phenotype (CIMP) is defined as a subset of colorectal cancers (CRCs) with remarkably high levels of DNA methylation, it is not known whether epigenetic processes are also involved in CIMP-negative tumors. We analyzed the DNA methylation profiles of 94 CRCs and their corresponding normal-appearing colonic mucosa with 11 different markers, including the five classical CIMP markers. The CIMP markers were frequently methylated in proximal CRCs (p < 0.01); however, RASSF1A methylation levels were significantly higher in distal CRCs, the majority of which are CIMP-negative (p < 0.05). Similarly, methylation levels of RASSF1A and SFRP1 in the normal-appearing mucosae of distal CRC cases were significantly higher than those in the proximal CRC cases (p < 0.05). They were also positively correlated with age (RASSF1A, p < 0.01; SFRP1, p < 0.01). Microarray-based genome-wide DNA methylation analysis of 18 CRCs revealed that 168 genes and 720 genes were preferentially methylated in CIMP-negative distal CRCs and CIMP-positive CRCs, respectively. Interestingly, more than half of the hypermethylated genes in CIMP-negative distal CRCs were also methylated in the normal-appearing mucosae, indicating that hypermethylation in CIMP-negative distal CRCs is more closely associated with age-related methylation. By contrast, more than 60% of the hypermethylated genes in CIMP-positive proximal CRCs were cancer specific (p < 0.01). These data altogether suggest that CpG island promoters appear to be methylated in different ways depending on location, a finding which may imply the presence of different mechanisms for the acquisition of epigenetic changes during colon tumorigenesis.]]> Thu, 02 Sep 2010 00:00:00 EDT Bakshi R, Hassan MQ, Pratap J, Lian JB, Montecino MA, van Wijnen AJ, Stein JL, Imbalzano AN, Stein GS
J Cell Physiol (Nov 2010)

The acute myeloid leukemia 1 (AML1, RUNX1) transcription factor is a key regulator of hematopoietic differentiation that forms multi-protein complexes with co-regulatory proteins. These complexes are assembled at target gene promoters in nuclear microenvironments to mediate phenotypic gene expression and chromatin-related epigenetic modifications. Here, immunofluorescence microscopy and biochemical assays are used to show that RUNX1 associates with the human ATP-dependent SWI/SNF chromatin remodeling complex. The SWI/SNF subunits BRG1 and INI1 bind in vivo to RUNX1 target gene promoters (e.g., GMCSF, IL3, MCSF-R, MIP, and p21). These interactions correlate with histone modifications characteristic of active chromatin, including acetylated H4 and dimethylated H3 lysine 4. Downregulation of RUNX1 by RNA interference diminishes the binding of BRG1 and INI1 at selected target genes. Taken together, our findings indicate that RUNX1 interacts with the human SWI/SNF complex to control hematopoietic-specific gene expression.]]> Mon, 30 Aug 2010 00:00:00 EDT Yun SJ, Byun K, Bhin J, Oh JH, Nhung le TH, Hwang D, Lee B
J Cell Physiol (Nov 2010)

Neural stem cells (NSCs) are self-renewing, multipotent cells that can generate neurons, astrocytes, and oligodendrocytes of the nervous system. NSCs have been extensively studied because they can be used to treat impaired cells and tissues or improve regenerative power of degenerating cells in neurodegenerative diseases or spinal cord injuries. For successful clinical applications of NSCs, it is essential to understand the mechanisms underlying self-renewal and differentiation of NSCs, which involve complex interplays among key factors including transcription factors, epigenetic control, microRNAs, and signaling pathways. Despite numerous studies on such factors, a holistic view of their interplays during neural development still remains elusive. In this review, we present recently identified potential regulatory factors and their targets by genomics and proteomics technologies and then integrate them into regulatory networks that describe their complex interplays to achieve self-renewal and differentiation of NSCs.]]> Mon, 30 Aug 2010 00:00:00 EDT Rasmussen TP, Corry GN
J Cell Physiol (Nov 2010)

Mammals, like all multicellular organisms, develop from a single cell--the totipotent zygote. During preimplantation development and subsequent development in utero, over 200 distinct cell types are established and integrated into the organ systems and tissues of the developing organism. Much of the field of mammalian developmental biology is devoted to investigation of mechanisms that govern the formation of complete organs and tissues. In contrast to later development, which consumes the vast majority of time associated with development in utero, preimplantation development and germ layer specification occur rapidly. Yet knowledge is limited regarding the regulatory mechanisms that specify the transient, but pluripotent, cellular lineages that form during the initial stages of mammalian development. Gametogenesis and preimplantation development are marked by dramatic and pervasive epigenetic changes rooted in chromatin dynamics. The fundamental mechanisms that specify subsequent cellular lineages of the conceptus are only now becoming understood, and tend to rely relatively heavily upon broad epigenetic mechanisms in addition to master transcription factors. This review considers epigenetic regulation in the very earliest stages of preimplantation development. In addition, recent advances which indicate that some epigenetic coding is imposed during gametogenesis and maintained during preimplantation development are considered.]]> Mon, 30 Aug 2010 00:00:00 EDT Stejskal S, Koutna I, Matula P, Rucka Z, Danek O, Maska M, Kozubek M
Epigenetics (Nov 2010)

Changes in nuclear architecture play an important role in the regulation of gene expression. The importance of epigenetic changes is observed during granulopoiesis, when changes in the nuclear architecture are considered a major factor that influences the downregulation of genes. We aimed to assess the influence of chromatin condensation on the regulation of gene expression during granulopoiesis. Based on a previously published microarray analysis, we chose loci with different levels of transcriptional activity during granulopoiesis. Fluorescent in situ hybridization (FISH) and immunofluorescent labelling of RNA polymerase II were used to determine the relationship between the transcriptional activity of gene clusters and their localization within areas with different levels of chromatin condensation. Although active loci were positioned outside of areas of condensed chromatin, downregulation of genes during granulopoiesis was not accompanied by a shift of the downregulated loci to condensed areas. Only the beta-globin cluster was subjected to chromatin condensation and localized to condensed areas. Our results indicate that granulopoiesis is accompanied by a non-random, tissue-specific pattern of chromatin condensation. Furthermore, we observed that the decrease in the quantity of RNA polymerase II correlates with the differentiation process and likely acts in synergy with chromatin condensation to downregulate total gene expression.]]> Fri, 27 Aug 2010 00:00:00 EDT Bapat SA, Jin V, Berry N, Balch C, Sharma N, Kurrey N, Zhang S, Fang F, Lan X, Li M, Kennedy B, Bigsby RM, Huang TH, Nephew KP
Epigenetics (Nov 2010)

"Epigenetic plasticity" refers to the capability of mammalian cells to alter their differentiation status via chromatin remodeling-associated alterations in gene expression. While epigenetic plasticity has been best associated with lineage commitment of embryonic stem cells, recent studies have demonstrated chromatin remodeling even in terminally differentiated normal cells and advanced-stage melanoma and breast cancer cells, in context-dependent responses to alterations in their microenvironment. In the current study, we extend this attribute of epigenetic plasticity to aggressive ovarian cancer cells, by using an integrative approach to associate cellular phenotypes with chromatin modifications ("ChIP-chip") and mRNA and microRNA expression. While we identified numerous gene promoters possessing the well-known "bivalent mark" of H3K27me3/H3K4me2, we also report 14 distinct, lesser known bi-, tri- and tetravalent combinations of activating and repressive chromatin modifications, in platinum-resistant CP 70 ovarian cancer cells. The vast majority (>90%) of all the histone marks studied localized to regions within 2,000 bp of transcription start sites, supporting a role in gene regulation. Upon a simple alteration in the microenvironment, transition from two- to three-dimensional culture, an increase (17-38%) in repressive-only marked promoters was observed, concomitant with a decrease (31-21%) in multivalent (i.e., juxtaposed permissive and repressive histone marked) promoters. Like embryonic/tissue stem and other (non-ovarian) carcinoma cells, ovarian cancer cell epigenetic plasticity reflects an inherent transcriptional flexibility for context-responsive alterations in phenotype. It is possible that this plasticity could be therapeutically exploited for the management of this lethal gynecologic malignancy.]]> Fri, 27 Aug 2010 00:00:00 EDT Yamada N, Nishida Y, Yokoyama S, Tsutsumida H, Houjou I, Kitamoto S, Goto M, Higashi M, Yonezawa S
J Hepatobiliary Pancreat Sci (Nov 2010)

BACKGROUND AND PURPOSE: High de novo expression of MUC5AC (a gastric-type secreted mucin) is observed in many types of pancreatobiliary neoplasms, including precursor lesions. In this study, we show that the DNA methylation pattern is intimately correlated with MUC5AC expression in ten cancer cell lines (breast, lung, pancreas, and colon). METHODS: The CpG methylation status of the MUC5AC promoter from -3855 to +321 was mapped using MassARRAY analysis, which utilizes base-specific cleavage of nucleic acids. ChIP assays and micro-RNA (miRNA) microarray expression profiling were also carried out in both MUC5AC-positive cells and in those with no or low MUC5AC expression. RESULTS: In the distal region from -3718 to -3670 of the promoter, MUC5AC-negative cancer cells (e.g., MDA-MB-453) were highly methylated, whereas MUC5AC-positive cells (e.g., MCF-7) had low methylation levels. The modification status of histone H3 lysine 9 (H3-K9) was also closely related to MUC5AC expression. Expression levels of miRNAs in the cancer cells were not correlated with MUC5AC expression. CONCLUSION: Our results indicate that MUC5AC is regulated by CpG methylation and histone H3-K9 modification of the MUC5AC promoter distal region, but not by miRNAs. An understanding of the epigenetic regulation of MUC5AC may be of importance for the diagnosis of carcinogenic risk in the pancreatobiliary system.]]> Tue, 24 Aug 2010 00:00:00 EDT Sui L, Li BM
Steroids (Dec 2010)

Thyroid hormones have long been known to play important roles in the development and functions of the central nervous system, however, the precise molecular mechanisms that regulate thyroid hormone-responsive gene expression are not well understood. The present study investigated the role of DNA methylaion and histone acetylation in the effects of perinatal hypothyroidism on regulation of reelin and brain-derived neurotrophic factor (BDNF) gene expression in rat hippocampus. The findings indicated that the activities of DNA methyltransferase (DNMT), methylated reelin and BDNF genes were up-regulated, whereas, the activities of histone acetylases (HAT), the levels of global acetylated histone 3 (H3) and global acetylated histone 4 (H4), and acetylated H3, acetylated H4 at reelin promoter and at BDNF gene promoter for exon II were down-regulated in the hippocampus at the developmental stage of the hypothyroid animals. These results suggest that epigenetic modification of chromatin might underlie the mechanisms of hypothyroidism-induced down-regulation of reelin and BDNF gene expression in developmental rat hippocampus.]]> Mon, 23 Aug 2010 00:00:00 EDT Popov N, Gil J
Epigenetics (Nov 2010)

The INK4b-ARF-INK4a locus encodes for two cyclin-dependent kinase inhibitors, p15(INK4b) and p16(INK4a) and a regulator of the p53 pathway, ARF. In addition ANRIL, a non-coding RNA, is also transcribed from the locus. ARF, p15(INK4b) and p16(INK4a) are well-established tumor suppressors which function is frequently disabled in human cancers. Recent studies showed that single nucleotide polymorphisms mapping in the vicinity of ANRIL are linked to a wide spectrum of conditions, including cardiovascular disease, ischemic stroke, type 2 diabetes, frailty and Alzheimer's disease. The INK4b-ARF-INK4a locus is regulated by Polycomb repressive complexes (PRCs) and its expression can be invoked by activating signals. Other epigenetic modifiers such as the histone demethylases JMJD3 and JHDM1B, the SWI/SNF chromatin remodeling complex and DNA methyltransferases regulate the locus interplaying with PRCs. In view of the intimate involvement of the INK4b-ARF-INK4a locus on disease, to understand its regulation is the first step for manipulate it to therapeutic benefit.]]> Wed, 18 Aug 2010 00:00:00 EDT Jia Y, Yang Y, Liu S, Herman JG, Guo M, Lu F
Epigenetics (Nov 2010)

SRY-box containing gene 17 (SOX17) was reported to be indispensable for embryonic development and a candidate tumor suppressor gene which antagonizes the canonical WNT/beta-catenin signaling pathway in colorectal cancer. In this study, we investigated the function and epigenetic regulation of SOX17 in human hepatocellular carcinoma (HCC). DNA methylation of SOX17 was analyzed in 62 human HCC tissues and HCC cell lines by MSP. A role as a tumor suppressor gene was evaluated by colony formation assay and regulation of WNT/beta-catenin signal pathway by SOX17 was determined by IHC and luciferase reporter assay. DNA methylation of the SOX17 promoter region occurs in 82% of HCC tissues and is associated with nuclear accumulation of beta-catenin. Restoration of SOX17 inhibits HepG2 colony formation and beta-catenin/TCF-dependent transcription with the presence of HMG box in SOX17. In conclusion, SOX17 negatively regulates canonical WNT/beta-catenin signaling pathway and inhibits human HCC cells growth, providing an explanation for the loss of expression by epigenetic mechanisms in these tumors.]]> Wed, 18 Aug 2010 00:00:00 EDT Urdinguio RG, Fernandez AF, Lopez-Nieva P, Rossi S, Huertas D, Kulis M, Liu CG, Croce C, Calin GA, Esteller M
Epigenetics (Oct 2010)

MicroRNAs (miRNAs) are short non-coding RNA molecules that regulate post-transcriptional gene expression. They influence a wide range of physiological functions, including neuronal processes, and are regulated by various mechanisms, such as DNA methylation. This epigenetic mark is recognized by transcriptional regulators such as the methyl CpG binding protein Mecp2. Rett syndrome is a complex neurological disorder that has been associated with mutations in the gene coding for Mecp2. Thus, we examined the possible miRNA misregulation caused by Mecp2 absence in a mouse model of Rett syndrome. Using miRNA expression microarrays, we observed that the brain of Rett syndrome mice undergoes a disruption of the expression profiles of miRNAs. Among the significantly altered miRNAs (26%, 65 of 245), overall downregulation of these transcripts was the most common feature (71%), while the remaining 30% were upregulated. Further validation by quantitative RT-PCR demonstrated that the most commonly disrupted miRNAs were miR-146a, miR-146b, miR-130, miR-122a, miR-342 and miR-409 (downregulated) and miR-29b, miR329, miR-199b, miR-382, miR-296, miR-221 and miR-92 (upregulated). Most importantly, transfection of miR-146a in a neuroblastoma cell line caused the downregulation of IL-1 receptor-associated kinase 1 (Irak1) levels, suggesting that the identified defect of miR-146a in Rett syndrome mice brains might be responsible for the observed upregulation of Irak1 in this model of the human disease. Overall, we provide another level of molecular deregulation occurring in Rett syndrome that might be useful for understanding the disease and for designing targeted therapies.]]> Wed, 18 Aug 2010 00:00:00 EDT Giuffrida D, Rogers IM
Recent Pat Anticancer Drug Discov (Nov 2010)

Many studies have demonstrated that most cancers are clonal and are maintained by a cancer stem cell. Cancer stem cells have been identified in blood, breast, brain, lungs, gastrointestinal, prostate and ovarian cancer. Under normal homeostasis tissue specific stem cell division would be under strict control. When proliferation becomes independent of normal cellular controls, cancer develops. Studies indicate that cancer stem cells maintain their ability to differentiate, which explains the variety of cell types observed in tumors. Most therapies are directed at the fast growing tumor mass but not the slow dividing cancer stem cells and therefore the cancer is not eradicated. Understanding the process of transformation from a highly regulated stem cell to a cancer stem cell requires an understanding of genetic and epigenetic processes as well as having an understanding of the stem cell niche and the interaction of the stem cells with supportive cells in the niche. Current research is helping us to understand stem cells and stem cell regulation and in turn this will help to develop novel therapies to eliminate cancer and the initiating cancer stem cell. The relevant patents on the stem cell regulation and cancer therapy by stem cells are discussed.]]> Mon, 09 Aug 2010 00:00:00 EDT Kelkar A, Deobagkar D
Epigenetics (Oct 2010)

X chromosome inactivation occurs in female mammals for the purpose of equalization of dosage of X linked genes between the two sexes. In eutherian mammals, one of the two copies of the X chromosome present in female individuals is silenced. Epigenetic modifications of both DNA and histones have been implicated to play a crucial role in this inactivation phenomenon. In this work, we have employed a novel method, published earlier by us, to assess the DNA methylation levels of genes on the inactive X chromosome in the human system. We have used genomic DNA from cells with the following karyotype, namely, 47,XXX and 45,X, to compare methylation levels from the active and inactive X. We report differential methylation of genes from the active and the inactive X chromosome with higher number of methylated genes being present on the inactive X chromosome. Our work has also led to the identification of motifs that show a significant similarity to microRNA sequences, which are enriched in methylated regions specific to the inactive X.]]> Mon, 26 Jul 2010 00:00:00 EDT Dyachenko O, Shevchuk T, Kretzner L, Buryanov Y, Smith S
Epigenetics (Oct 2010)

Non-CG methylation is well characterized in plants, where it appears to play a role in gene silencing and genomic imprinting. Although strong evidence for the presence of non-CG methylation in mammals has been available for some time, both its origin and function remain elusive. In this review we discuss available evidence on non-CG methylation in mammals in light of evidence suggesting that the human stem cell methylome contains significant levels of methylation outside the CG site.]]> Wed, 21 Jul 2010 00:00:00 EDT Wang X, Jin H
Epigenetics (Oct 2010)

Cancer development results from the accumulation of genetic and epigenetic changes. By interacting with intracellular signaling to promote carcinogenesis, epigenetic networks can actively transform cancer-promoting signals from tumor-permissive microenvironment to coordinate cellular proliferation and metabolism in the initiation and progression of cancers. As reported recently, NFkappaB which can be activated by many soluble bioactive factors enriched in tumor microenvironments can promote the switch of cellular glucose metabolism from oxidative phosphorylation to oxygen-independent glycolysis in tumor cells, in addition to its well-known anti-apoptosis functions. Such epigenetic trans-generation of microenvironmental factors plays important roles in the development of cancers, particularly inflammation-related or sporadic cancers.]]> Mon, 12 Jul 2010 00:00:00 EDT