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Sample records for aberrant gene methylation

  1. Aberrant Gene Promoter Methylation Associated with Sporadic Multiple Colorectal Cancer

    Victoria Gonzalo; Juan José Lozano; Jenifer Muñoz; Francesc Balaguer; Maria Pellisé; Cristina Rodríguez de Miguel; Montserrat Andreu; Rodrigo Jover; Xavier Llor; M Dolores Giráldez; Teresa Ocaña; Anna Serradesanferm; Virginia Alonso-Espinaco; Mireya Jimeno; Miriam Cuatrecasas

    2010-01-01

    BACKGROUND: Colorectal cancer (CRC) multiplicity has been mainly related to polyposis and non-polyposis hereditary syndromes. In sporadic CRC, aberrant gene promoter methylation has been shown to play a key role in carcinogenesis, although little is known about its involvement in multiplicity. To assess the effect of methylation in tumor multiplicity in sporadic CRC, hypermethylation of key tumor suppressor genes was evaluated in patients with both multiple and solitary tumors, as a proof-of-...

  2. Aberrant methylation of candidate tumor suppressor genes in neuroblastoma.

    Hoebeeck, Jasmien; Michels, Evi; Pattyn, Filip; Combaret, Valérie; Vermeulen, Joëlle; Yigit, Nurten; Hoyoux, Claire; Laureys, Geneviève; De Paepe, Anne; Speleman, Frank; Vandesompele, Jo

    2009-01-18

    CpG island hypermethylation has been recognized as an alternative mechanism for tumor suppressor gene inactivation. In this study, we performed methylation-specific PCR (MSP) to investigate the methylation status of 10 selected tumor suppressor genes in neuroblastoma. Seven of the investigated genes (CD44, RASSF1A, CASP8, PTEN, ZMYND10, CDH1, PRDM2) showed high frequencies (> or =30%) of methylation in 33 neuroblastoma cell lines. In 42 primary neuroblastoma tumors, the frequencies of methylation were 69%, CD44; 71%, RASSF1A; 56%, CASP8; 25%, PTEN; 15%, ZMYND10; 8%, CDH1; and 0%, PRDM2. Furthermore, CASP8 and CDH1 hypermethylation was significantly associated with poor event-free survival. Meta-analysis of 115 neuroblastoma tumors demonstrated a significant correlation between CASP8 methylation and MYCN amplification. In addition, there was a correlation between ZMYND10 methylation and MYCN amplification. The MSP data, together with optimized mRNA re-expression experiments (in terms of concentration and time of treatment and use of proper reference genes) further strengthen the notion that epigenetic alterations could play a significant role in NB oncogenesis. This study thus warrants the need for a global profiling of gene promoter hypermethylation to identify genome-wide aberrantly methylated genes in order to further understand neuroblastoma pathogenesis and to identify prognostic methylation markers. PMID:18819746

  3. Aberrant gene promoter methylation associated with sporadic multiple colorectal cancer.

    Victoria Gonzalo

    Full Text Available BACKGROUND: Colorectal cancer (CRC multiplicity has been mainly related to polyposis and non-polyposis hereditary syndromes. In sporadic CRC, aberrant gene promoter methylation has been shown to play a key role in carcinogenesis, although little is known about its involvement in multiplicity. To assess the effect of methylation in tumor multiplicity in sporadic CRC, hypermethylation of key tumor suppressor genes was evaluated in patients with both multiple and solitary tumors, as a proof-of-concept of an underlying epigenetic defect. METHODOLOGY/PRINCIPAL FINDINGS: We examined a total of 47 synchronous/metachronous primary CRC from 41 patients, and 41 gender, age (5-year intervals and tumor location-paired patients with solitary tumors. Exclusion criteria were polyposis syndromes, Lynch syndrome and inflammatory bowel disease. DNA methylation at the promoter region of the MGMT, CDKN2A, SFRP1, TMEFF2, HS3ST2 (3OST2, RASSF1A and GATA4 genes was evaluated by quantitative methylation specific PCR in both tumor and corresponding normal appearing colorectal mucosa samples. Overall, patients with multiple lesions exhibited a higher degree of methylation in tumor samples than those with solitary tumors regarding all evaluated genes. After adjusting for age and gender, binomial logistic regression analysis identified methylation of MGMT2 (OR, 1.48; 95% CI, 1.10 to 1.97; p = 0.008 and RASSF1A (OR, 2.04; 95% CI, 1.01 to 4.13; p = 0.047 as variables independently associated with tumor multiplicity, being the risk related to methylation of any of these two genes 4.57 (95% CI, 1.53 to 13.61; p = 0.006. Moreover, in six patients in whom both tumors were available, we found a correlation in the methylation levels of MGMT2 (r = 0.64, p = 0.17, SFRP1 (r = 0.83, 0.06, HPP1 (r = 0.64, p = 0.17, 3OST2 (r = 0.83, p = 0.06 and GATA4 (r = 0.6, p = 0.24. Methylation in normal appearing colorectal mucosa from patients with multiple and solitary CRC showed no relevant

  4. Aberrant CpG Island Methylation of Multiple Genes in Intrahepatic Cholangiocarcinoma

    Lee, Sun; Kim, Woo Ho; Jung, Hwoon-Yong; Yang, Moon Ho; Kang, Gyeong Hoon

    2002-01-01

    Aberrant methylation of promoter CpG islands of human genes has been known as an alternative mechanism of gene inactivation and contributes to the carcinogenesis in many human tumors. We attempted to determine the methylation status of 18 genes, or loci known to be frequently methylated in cancers of other organs, in 79 resected intrahepatic cholangiocarcinomas and 15 normal bile duct epithelium by methylation-specific polymerase chain reaction and correlated the data with clinicopathological...

  5. Aberrant DNA methylation at genes associated with a stem cell-like phenotype in cholangiocarcinoma tumours

    Sriraksa, Ruethairat; Zeller, Constanze; Dai, Wei; Siddiq, Afshan; Walley, Andrew J; LIMPAIBOON, TEMDUANG; Brown, Robert

    2013-01-01

    Genetic abnormalities of cholangiocarcinoma have been widely studied; however, epigenomic changes related to cholangiocarcinogenesis have been less well characterised. We have profiled the DNA methylomes of 28 primary cholangiocarcinoma and six matched adjacent normal tissues using Infinium’s HumanMethylation27 BeadChips with the aim of identifying gene sets aberrantly epigenetically regulated in this tumour type.

  6. Aberrant methylation patterns in cancer

    Hudler, Petra; Videtič, Alja

    2016-01-01

    Epigenetic mechanisms, such as DNA methylation, DNA hydroxymethylation, post-translational modifications (PTMs) of histone proteins affecting nucleosome remodelling, and regulation by small and large non-coding RNAs (ncRNAs) work in concert with cis and trans acting elements to drive appropriate gene expression. Advances in detection methods and development of dedicated platforms and methylation arrays resulted in an explo - sion of information on aberrantly methylated sequences linking devia...

  7. Aberrant DNA methylation in 5'regions of DNA methyltransferase genes in aborted bovine clones

    2008-01-01

    High rate of abortion and developmental abnormalities is thought to be closely associated with inefficient epigenetic reprogramming of the transplanted nuclei during bovine cloning.It is known that one of the important mechanisms for epigenetic reprogramming is DNA methylation.DNA methylation is established and maintained by DNA methyltransferases(DNMTs),therefore,it is postulated that the inefficient epigenetic reprogramming of transplanted nuclei may be due to abnormal expression of DNMTs.Since DNA methylation can strongly inhibit gene expression,aberrant DNA methylation of DNMT genes may disturb gene expression.But presently,it is not clear whether the methylation abnormality of DNMT genes is related to developmental failure of somatic cell nuclear transfer embryos.In our study,we analyzed methylation patterns of the 5' regions of four DNMT genes including Dnmt3a,Dnmt3b,Dnmtl and Dnmt2 in four aborted bovine clones.Using bisulfite sequencing method,we found that 3 out of 4 aborted bovine clones(AF1,AF2 and AF3)showed either hypermethylation or hypomethylation in the 5' regions of Dnmt3a and Dnmt3b.indicating that Dnmt3a and Dnmt3b genes are not properly reprogrammed.However,the individual AF4 exhibited similar methylation level and pattern to age-matched in vitro fertilized (IVF)fetuses.Besides,we found that tle 5'regions of Dnmtl and Dnmt2 were nearly completely unmethylated in all normal adults.IVF fetuses,sperm and aborted clones.Together,our results suggest that the aberrant methylation of Dnmt3a and Dnmt3b 5' regions is probably associated with the high abortion of bovine clones.

  8. Aberrant DNA methylation of cancer-related genes in giant breast fibroadenoma: a case report

    Orozco Javier I

    2011-10-01

    Full Text Available Abstract Introduction Giant fibroadenoma is an uncommon variant of benign breast lesions. Aberrant methylation of CpG islands in promoter regions is known to be involved in the silencing of genes (for example, tumor-suppressor genes and appears to be an early event in the etiology of breast carcinogenesis. Only hypermethylation of p16INK4a has been reported in non-giant breast fibroadenoma. In this particular case, there are no previously published data on epigenetic alterations in giant fibroadenomas. Our previous results, based on the analysis of 49 cancer-related CpG islands have confirmed that the aberrant methylation is specific to malignant breast tumors and that it is completely absent in normal breast tissue and breast fibroadenomas. Case presentation A 13-year-old Hispanic girl was referred after she had noted a progressive development of a mass in her left breast. On physical examination, a 10 × 10 cm lump was detected and axillary lymph nodes were not enlarged. After surgical removal the lump was diagnosed as a giant fibroadenoma. Because of the high growth rate of this benign tumor, we decided to analyze the methylation status of 49 CpG islands related to cell growth control. We have identified the methylation of five cancer-related CpG islands in the giant fibroadenoma tissue: ESR1, MGMT, WT-1, BRCA2 and CD44. Conclusion In this case report we show for the first time the methylation analysis of a giant fibroadenoma. The detection of methylation of these five cancer-related regions indicates substantial epigenomic differences with non-giant fibroadenomas. Epigenetic alterations could explain the higher growth rate of this tumor. Our data contribute to the growing knowledge of aberrant methylation in breast diseases. In this particular case, there exist no previous data regarding the role of methylation in giant fibroadenomas, considered by definition as a benign breast lesion.

  9. Aberrant gene methylation implicated in the progression of monoclonal gammopathy of undetermined significance to multiple myeloma

    Chim, Chor‐Sang; Liang, Raymond; Leung, Man‐Hin; Kwong, Yok‐Lam

    2007-01-01

    Malignant transformation is a multistep process that may involve dysregulation of oncogenes and tumour suppressor genes, and monoclonal gammopathy of undetermined significance (MGUS) is believed to be a precursor of multiple myeloma. To investigate whether aberrant promoter methylation might be involved in the evolution of MGUS to multiple myeloma, we examined the p16, protein tyrosine phosphatase, non-receptor type 6 (SHP1), death-associated protein (DAP) kinase, E-cadherin and oestrogen rec...

  10. Aberrant DNA methylation at genes associated with a stem cell-like phenotype in cholangiocarcinoma tumors.

    Sriraksa, Ruethairat; Zeller, Constanze; Dai, Wei; Siddiq, Afshan; Walley, Andrew J; Limpaiboon, Temduang; Brown, Robert

    2013-12-01

    Genetic abnormalities of cholangiocarcinoma have been widely studied; however, epigenomic changes related to cholangiocarcinogenesis have been less well characterized. We have profiled the DNA methylomes of 28 primary cholangiocarcinoma and six matched adjacent normal tissues using Infinium's HumanMethylation27 BeadChips with the aim of identifying gene sets aberrantly and epigenetically regulated in this tumor type. Using a linear model for microarray data, we identified 1610 differentially methylated autosomal CpG sites, with 809 hypermethylated (representing 603 genes) and 801 hypomethylated (representing 712 genes) in cholangiocarcinoma versus adjacent normal tissues (false-discovery rate ≤ 0.05). Gene ontology and gene set enrichment analyses identified gene sets significantly associated with hypermethylation at linked CpG sites in cholangiocarcinoma including homeobox genes and target genes of PRC2, EED, SUZ12, and histone H3 trimethylation at lysine 27. We confirmed frequent hypermethylation at the homeobox genes HOXA9 and HOXD9 by bisulfite pyrosequencing in a larger cohort of cholangiocarcinoma (n = 102). Our findings indicate a key role for hypermethylation of multiple CpG sites at genes associated with a stem cell-like phenotype as a common molecular aberration in cholangiocarcinoma. These data have implications for cholangiocarcinogenesis, as well as possible novel treatment options using histone methyltransferase inhibitors. PMID:24089088

  11. Aberrant DNA methylation at genes associated with a stem cell-like phenotype in cholangiocarcinoma tumours

    Dai, Wei; Siddiq, Afshan; Walley, Andrew J; Limpaiboon, Temduang; Brown, Robert

    2013-01-01

    Genetic abnormalities of cholangiocarcinoma have been widely studied; however, epigenomic changes related to cholangiocarcinogenesis have been less well characterised. We have profiled the DNA methylomes of 28 primary cholangiocarcinoma and six matched adjacent normal tissues using Infinium’s HumanMethylation27 BeadChips with the aim of identifying gene sets aberrantly epigenetically regulated in this tumour type. Using a linear model for microarray data we identified 1610 differentially methylated autosomal CpG sites with 809 CpG sites (representing 603 genes) being hypermethylated and 801 CpG sites (representing 712 genes) being hypomethylated in cholangiocarcinoma versus adjacent normal tissues (false discovery rate ≤ 0.05). Gene ontology and gene set enrichment analyses identified gene sets significantly associated with hypermethylation at linked CpG sites in cholangiocarcinoma including homeobox genes and target genes of PRC2, EED, SUZ12 and histone H3 trimethylation at lysine 27. We confirmed frequent hypermethylation at the homeobox genes HOXA9 and HOXD9 by bisulfite pyrosequencing in a larger cohort of cholangiocarcinoma (n = 102). Our findings indicate a key role for hypermethylation of multiple CpG sites at genes associated with a stem cell-like phenotype as a common molecular aberration in cholangiocarcinoma. These data have implications for cholangiocarcinogenesis, as well as possible novel treatment options using histone methyltransferase inhibitors. PMID:24089088

  12. Aberrant methylation of the Adenomatous Polyposis Coli (APC) gene promoter is associated with the inflammatory breast cancer phenotype

    Van der Auwera, I; Laere, S.J.; Van den Bosch, S M; Van den Eynden, G. G.; Trinh, B X; van Dam, P A; Colpaert, C G; van Engeland, M; Van Marck, E A; Vermeulen, P B; Dirix, L Y

    2008-01-01

    Aberrant methylation of the adenomatous polyposis coli (APC) gene promoter occurs in about 40% of breast tumours and has been correlated with reduced APC protein levels. To what extent epigenetic alterations of the APC gene may differ according to specific breast cancer phenotypes, remains to be elucidated. Our aim was to explore the role of APC methylation in the inflammatory breast cancer (IBC) phenotype. The status of APC gene promoter hypermethylation was investigated in DNA from normal b...

  13. Prioritizing cancer-related genes with aberrant methylation based on a weighted protein-protein interaction network

    Lv Jie

    2011-10-01

    Full Text Available Abstract Background As an important epigenetic modification, DNA methylation plays a crucial role in the development of mammals and in the occurrence of complex diseases. Genes that interact directly or indirectly may have the same or similar functions in the biological processes in which they are involved and together contribute to the related disease phenotypes. The complicated relations between genes can be clearly represented using network theory. A protein-protein interaction (PPI network offers a platform from which to systematically identify disease-related genes from the relations between genes with similar functions. Results We constructed a weighted human PPI network (WHPN using DNA methylation correlations based on human protein-protein interactions. WHPN represents the relationships of DNA methylation levels in gene pairs for four cancer types. A cancer-associated subnetwork (CASN was obtained from WHPN by selecting genes associated with seed genes which were known to be methylated in the four cancers. We found that CASN had a more densely connected network community than WHPN, indicating that the genes in CASN were much closer to seed genes. We prioritized 154 potential cancer-related genes with aberrant methylation in CASN by neighborhood-weighting decision rule. A function enrichment analysis for GO and KEGG indicated that the optimized genes were mainly involved in the biological processes of regulating cell apoptosis and programmed cell death. An analysis of expression profiling data revealed that many of the optimized genes were expressed differentially in the four cancers. By examining the PubMed co-citations, we found 43 optimized genes were related with cancers and aberrant methylation, and 10 genes were validated to be methylated aberrantly in cancers. Of 154 optimized genes, 27 were as diagnostic markers and 20 as prognostic markers previously identified in literature for cancers and other complex diseases by searching Pub

  14. Involvement of aberrant DNA methylation on reduced expression of lysophosphatidic acid receptor-1 gene in rat tumor cell lines

    Lysophosphatidic acid (LPA) is a bioactive phospholipid that stimulates cell proliferation, migration, and protects cells from apoptosis. It interacts with specific G protein-coupled transmembrane receptors. Recently, it has been reported that alterations of LPA receptor expression might be important in the malignant transformation of tumor cells. Therefore, to assess an involvement of DNA methylation in reduced expression of the LPA receptor-1 (lpa1) gene, we investigated the expression of the lpa1 gene and its DNA methylation patterns in rat tumor cell lines. Both rat brain-derived neuroblastoma B103 and liver-derived hepatoma RH7777 cells used in this study indicated no expression of lpa1. For the analysis of methylation status, bisulfite sequencing was performed with B103 and RH7777 cells, comparing with other lpa1 expressed cells and normal tissues of brain and liver. The lpa1 expressed cells and tissues were all unmethylated in this region of lpa1. In contrast, both B103 and RH7777 cells were highly methylated, correlating with reduced expression of the lpa1. Treatment with 5-aza 2'-deoxycytidine induced expression of lpa1 gene in B103 and RH7777 cells after 24 h. In RH7777 cells treated with 5-aza 2'-deoxycytidine, stress fiber formation was also observed in response to LPA in RH7777 cells, but not in untreated RH7777 cells. These results suggest that aberrant DNA methylation of the lpa1 gene may be involved in its reduced expression in rat tumor cells

  15. Aberrant methylation of the M-type phospholipase A2 receptor gene in leukemic cells

    Menschikowski Mario

    2012-12-01

    Full Text Available Abstract Background The M-type phospholipase A2 receptor (PLA2R1 plays a crucial role in several signaling pathways and may act as tumor-suppressor. This study examined the expression and methylation of the PLA2R1 gene in Jurkat and U937 leukemic cell lines and its methylation in patients with myelodysplastic syndrome (MDS or acute leukemia. Methods Sites of methylation of the PLA2R1 locus were identified by sequencing bisulfite-modified DNA fragments. Methylation specific-high resolution melting (MS-HRM analysis was then carried out to quantify PLA2R1 methylation at 5`-CpG sites identified with differences in methylation between healthy control subjects and leukemic patients using sequencing of bisulfite-modified genomic DNA. Results Expression of PLA2R1 was found to be completely down-regulated in Jurkat and U937 cells, accompanied by complete methylation of PLA2R1 promoter and down-stream regions; PLA2R1 was re-expressed after exposure of cells to 5-aza-2´-deoxycytidine. MS-HRM analysis of the PLA2R1 locus in patients with different types of leukemia indicated an average methylation of 28.9% ± 17.8%, compared to less than 9% in control subjects. In MDS patients the extent of PLA2R1 methylation significantly increased with disease risk. Furthermore, measurements of PLA2R1 methylation appeared useful for predicting responsiveness to the methyltransferase inhibitor, azacitidine, as a pre-emptive treatment to avoid hematological relapse in patients with high-risk MDS or acute myeloid leukemia. Conclusions The study shows for the first time that PLA2R1 gene sequences are a target of hypermethylation in leukemia, which may have pathophysiological relevance for disease evolution in MDS and leukemogenesis.

  16. Aberrant methylation of the M-type phospholipase A2 receptor gene in leukemic cells

    The M-type phospholipase A2 receptor (PLA2R1) plays a crucial role in several signaling pathways and may act as tumor-suppressor. This study examined the expression and methylation of the PLA2R1 gene in Jurkat and U937 leukemic cell lines and its methylation in patients with myelodysplastic syndrome (MDS) or acute leukemia. Sites of methylation of the PLA2R1 locus were identified by sequencing bisulfite-modified DNA fragments. Methylation specific-high resolution melting (MS-HRM) analysis was then carried out to quantify PLA2R1 methylation at 5-CpG sites identified with differences in methylation between healthy control subjects and leukemic patients using sequencing of bisulfite-modified genomic DNA. Expression of PLA2R1 was found to be completely down-regulated in Jurkat and U937 cells, accompanied by complete methylation of PLA2R1 promoter and down-stream regions; PLA2R1 was re-expressed after exposure of cells to 5-aza-2´-deoxycytidine. MS-HRM analysis of the PLA2R1 locus in patients with different types of leukemia indicated an average methylation of 28.9% ± 17.8%, compared to less than 9% in control subjects. In MDS patients the extent of PLA2R1 methylation significantly increased with disease risk. Furthermore, measurements of PLA2R1 methylation appeared useful for predicting responsiveness to the methyltransferase inhibitor, azacitidine, as a pre-emptive treatment to avoid hematological relapse in patients with high-risk MDS or acute myeloid leukemia. The study shows for the first time that PLA2R1 gene sequences are a target of hypermethylation in leukemia, which may have pathophysiological relevance for disease evolution in MDS and leukemogenesis

  17. Dysfunction of endothelial NO system originated from homocysteine-induced aberrant methylation pattern in promoter region of DDAH2 gene

    ZHANG Jing-ge; LIU Jun-xu; LI Zhu-hua; WANG Li-zhen; JIANG Yi-deng; WANG Shu-ren

    2007-01-01

    Background Hyperhomocysteinemia (HHcy)-mediated dysfunction of endothelial NO system is an important mechanism for atherosclerotic pathogenesis.Dimethylarginine dimethylaminohydrolase (DDAH) is the key enzyme for degrading asymmetric dimethylarginine (ADMA),which is an endogenous inhibitor of endothelial nitric oxide (NO) synthase (eNOS).This study was designed to investigate whether the dysfunction of endothelial NO system originates from HHcy-mediated aberrant methylation modification in promotor region of DDAH2 gene.Methods Human umbilical vein endothelial cells (HUVECs) were cultured to the third generation and treated with homocysteine (Hcy) at different concentrations (0,10,30,100,and 300 μmol/L) for 72 hours.The methylation pattern in promoter region CpG island of DDAH2 gene was analyzed by nested methylation-specific PCR (nMSP).The mRNA expression of eNOS gene and DDAH2 gene was detected by semi-quantitative RT-PCR.The activity of DDAH2 and eNOS in cells,and the concentrations of ADMA and NO in culture medium were assayed respectively.Results Mild increased concentration of Hcy (10 and 30 μmol/L) induced hypomethylation,while high concentration of Hcy (100 and 300 μmol/L) induced hypermethylation in the promoter CpG island of DDAH2 gene.The mRNA expression of DDAH2 increased in mild enhanced concentration of Hcy,and decreased in high concentration of Hcy correspondingly.The inhibition of DDAH2 activity,the increase of ADMA concentration,the reduction of eNOS activity and the decrease of NO production were all consistently relevant to the alteration of Hcy concentration Conclusion The increased concentration of Hcy induced aberrant methylation pattern in promotor region of DDAH2 gene and the successive alterations in DDAH/ADMA/NOS/NO pathway,which showed highly relevant and dose-effect relationship.The results suggested that the dysfunction of endothelial NO system induced by HHcy could be partially originated from Hcy-mediated aberrant methylation in

  18. Aberrant Promoter Methylation of p16 and MGMT Genes in Lung Tumors from Smoking and Never-Smoking Lung Cancer Patients

    Yang Liu

    2006-01-01

    Full Text Available Aberrant methylation in gene promoter regions leads to transcriptional inactivation of cancer-related genes and plays an integral role in tumorigenesis. This alteration has been investigated in lung tumors primarily from smokers, whereas only a few studies involved never-smokers. Here, we applied methylation-specific polymerase chain reaction to compare the frequencies of the methylated promoter of p16 and O6-methylguanine-DNA methyltransferase (MGMT genes in lung tumors from 122 patients with non-small cell lung cancer, including 81 smokers and 41 never-smokers. Overall, promoter methylation was detected in 52.5% (64 of 122 and 30.3°/a (37 of 122 of the p16 and MGMT genes, respectively. Furthermore, the frequency of promoter methylation was significantly higher among smokers, compared with never-smokers, for both the p16 [odds ratio (OR = 3.28; 95% confidence interval (CI = 1.28-8.39; P = .013] and MGMT (OR = 3.93; 95% CI =1.27-12.21; P = .018 genes. The trend for a higher promoter methylation frequency of these genes was also observed among female smokers compared with female never-smokers. Our results suggest an association between tobacco smoking and an increased incidence of aberrant promoter methylation of the p16 and MGMT genes in non-small cell lung cancer.

  19. Aberrant DNA Methylation of P16, MGMT, and hMLH1 Genes in Combination with MTHFR C677T Genetic Polymorphism in gastric cancer

    Song, Binbin; Ai, Jiang; Kong, Xianghong; Liu, Dexin; Li, Jun

    2013-01-01

    Objective: We aimed to explore the association of P16, MGMT and HMLH1 with gastric cancer and their relation with Methylenetetrahydrofolate reductase (MTHFR). Methods: 322 gastric patients who were confirmed with pathological diagnosis were included in our study. Aberrant DNA methylation of P16, MGMT and HMLH1 and polymorphisms of MTHFR C677T and A1298C were detected using PCR-RFLP. Results: The proportions of DNA hypermethylation in P16, MGMT and hMLH1 genes in gastric cancer tissues were 75...

  20. Detection of aberrant methylation of a six-gene panel in serum DNA for diagnosis of breast cancer.

    Shan, Ming; Yin, Huizi; Li, Junnan; Li, Xiaobo; Wang, Dong; Su, Yonghui; Niu, Ming; Zhong, Zhenbin; Wang, Ji; Zhang, Xianyu; Kang, Wenli; Pang, Da

    2016-04-01

    Detection of breast cancer at an early stage is the key for successful treatment and improvement of outcome. However the limitations of mammography are well recognized, especially for those women with premenopausal breast cancer. Novel approaches to breast cancer screening are necessary, especially in the developing world where mammography is not feasible. In this study, we examined the promoter methylation of six genes (SFN, P16, hMLH1, HOXD13, PCDHGB7 and RASSF1a) in circulating free DNA (cfDNA) extracted from serum. We used a high-throughput DNA methylation assay (MethyLight) to examine serum from 749 cases including breast cancer patients, patients with benign breast diseases and healthy women. The six-gene methylation panel test achieved 79.6% and 82.4% sensitivity with a specificity of 72.4% and 78.1% in diagnosis of breast cancer when compared with healthy and benign disease controls, respectively. Moreover, the methylation panel positive group showed significant differences in the following independent variables: (a) involvement of family history of tumors; (b) a low proliferative index, ki-67; (c) high ratios in luminal subtypes. Additionally the panel also complemented some breast cancer cases which were neglected by mammography or ultrasound. These data suggest that epigenetic markers in serum have potential for diagnosis of breast cancer. PMID:26918343

  1. Aberrant DNA methylation in cloned ovine embryos

    LIU Lei; HOU Jian; LEI TingHua; BAI JiaHua; GUAN Hong; AN XiaoRong

    2008-01-01

    By using the approach of immunofluorescence staining with an antibody against 5-methylcytosine (5MeC), the present study detected the DNA methylation patterns of cloned ovine embryos. The em-bryos derived from in vitro fertilization were also examined for reference purpose. The results showed that: (1) during the pre-implantation development, cloned embryos displayed a similar demethylation profile to the fertilized embryos; that is, the methylation level decreased to the lowest at 8-cell stage, and then increased again at morulae stage. However, methylation level was obviously higher in cloned embryos than in stage-matched fertilized embryos, especially at 8-cell stage and afterwards; (2) at blastocyst stage, the methylation pattern in cloned embryos was different from that in fertilized em-bryos. In cloned blastocyst, inner cell mass (ICM) exhibited a comparable level to trophectoderm cells (TE), while in in-vitro fertilized blastocyst the methylation level of ICM was lower than that of TE, which is not consistent with that reported by other authors. These results indicate that DNA methylation is abnormally reprogrammed in cloned embryos, implying that aberrant DNA methylation reprogramming may be one of the factors causing cloned embryos developmental failure.

  2. Aberrant DNA methylation in cervical carcinogenesis

    Hui-Juan Yang

    2013-01-01

    Persistent infection with high-risk types of human papillomavirus(HPV) is known to cause cervical cancer; however,additional genetic and epigenetic alterations are required for progression from precancerous disease to invasive cancer.DNA methylation is an early and frequent molecular alteration in cervical carcinogenesis.In this review,we summarize DNA methylation within the HPV genome and human genome and identify its clinical implications.Methylation of the HPV long control region (LCR) and L1 gene is common during cervical carcinogenesis and increases with the severity of the cervical neoplasm.The L1 gene of HPV16 and HPV18 is consistently hypermethylated in invasive cervical cancers and can potentially be used as a clinical marker of cancer progression.Moreover,promoters of tumor suppressor genes (TSGs) involved in many cellular pathways are methylated in cervical precursors and invasive cancers.Some are associated with squamous cell carcinomas,and others are associated with adenocarcinomas.Identification of methylated TSGs in Pap smear could be an adjuvant test in cervical cancer screening for triage of women with high-risk HPV,atypical squamous cells of undetermined significance,or low grade squamous intraepithelial lesion (LSIL).However,consistent panels must be validated for this approach to be translated to the clinic.Furthermore,reversion of methylated TSGs using demethylating drugs may be an alternative anticancer treatment,but demethylating drugs without toxic carcinogenic and mutagenic properties must be identified and validated.

  3. Aberrant DNA Methylation of P16, MGMT, and hMLH1 Genes in Combination with MTHFR C677T Genetic Polymorphism in gastric cancer

    Song, Binbin; Ai, Jiang; Kong, Xianghong; Liu, Dexin; Li, Jun

    2013-01-01

    Objective: We aimed to explore the association of P16, MGMT and HMLH1 with gastric cancer and their relation with Methylenetetrahydrofolate reductase (MTHFR). Methods: 322 gastric patients who were confirmed with pathological diagnosis were included in our study. Aberrant DNA methylation of P16, MGMT and HMLH1 and polymorphisms of MTHFR C677T and A1298C were detected using PCR-RFLP. Results: The proportions of DNA hypermethylation in P16, MGMT and hMLH1 genes in gastric cancer tissues were 75.2% (242/322), 27.6% (89/322) and 5.3% (17/322), respectively. In the remote normal-appearing tissues, 29.5% (95/322) and 16.1%(52/322) showed hypermethylation in P16 and MGMT genes, respectively. We found a significantly higher proportion of DNA hypermethylation of P16 in patients with N1 TNM stage in cancer tissues and remote normal-appearing tissues (P<0.05). Similarly, we found DNA hypermethylation of MGMT had significantly higher proportion in N1 and M1 TNM stage (P<0.05). Individuals with homozygotes (TT) of MTHFR C677T had significant risk of DNA hypermethylation of MGMT in cancer tissues [OR (95% CI)=4.27(1.76-7.84)], and a significant risk was also found in those carrying MTHFR 677CT/TT genotype [OR (95% CI)= 3.27(1.21-4.77)]. Conclusion: We found the aberrant hypermethylation of cancer-related genes, such as P16, MGMT and HMLH1, could be predictive biomarkers for detection of gastric cancer. PMID:24550949

  4. Aberrantly methylated DNA as a biomarker in breast cancer

    Kristiansen, Søren; Jørgensen, Lars Mønster; Guldberg, Per;

    2013-01-01

    hypermethylation events, their use as tumor biomarkers is usually not hampered by analytical signals from normal cells, which is a general problem for existing protein tumor markers used for clinical assessment of breast cancer. There is accumulating evidence that DNA-methylation changes in breast cancer patients......Aberrant DNA hypermethylation at gene promoters is a frequent event in human breast cancer. Recent genome-wide studies have identified hundreds of genes that exhibit differential methylation between breast cancer cells and normal breast tissue. Due to the tumor-specific nature of DNA...... occur early during tumorigenesis. This may open up for effective screening, and analysis of blood or nipple aspirate may later help in diagnosing breast cancer. As a more detailed molecular characterization of different types of breast cancer becomes available, the ability to divide patients into...

  5. Molecular detection of noninvasive and invasive bladder tumor tissues and exfoliated cells by aberrant promoter methylation of laminin-5 encoding genes.

    Sathyanarayana, Ubaradka G; Maruyama, Riichiroh; Padar, Asha; Suzuki, Makoto; Bondaruk, Jolanta; Sagalowsky, Arthur; Minna, John D; Frenkel, Eugene P; Grossman, H Barton; Czerniak, Bogdan; Gazdar, Adi F

    2004-02-15

    Laminin-5 (LN5) anchors epithelial cells to the underlying basement membrane, and it is encoded by three distinct genes: LAMA3, LAMB3, and LAMC2. To metastasize and grow, cancer cells must invade and destroy the basement membrane. Our previous work has shown that epigenetic inactivation is a major mechanism of silencing LN5 genes in lung cancers. We extended our methylation studies to resected bladder tumors (n = 128) and exfoliated cell samples (bladder washes and voided urine; n = 71) and correlated the data with clinicopathologic findings. Nonmalignant urothelium had uniform expression of LN5 genes and lacked methylation. The methylation frequencies for LN5 genes in tumors were 21-45%, and there was excellent concordance between methylation in tumors and corresponding exfoliated cells. Methylation of LAMA3 and LAMB3 and the methylation index were correlated significantly with several parameters of poor prognosis (tumor grade, growth pattern, muscle invasion, tumor stage, and ploidy pattern), whereas methylation of LAMC2 and methylation index were associated with shortened patient survival. Of particular interest, methylation frequencies of LAMA3 helped to distinguish invasive (72%) from noninvasive (12%) tumors. These results suggest that methylation of LN5 genes has potential clinical applications in bladder cancers. PMID:14973053

  6. Methylated genes as new cancer biomarkers.

    Duffy, M J

    2012-02-01

    Aberrant hypermethylation of promoter regions in specific genes is a key event in the formation and progression of cancer. In at least some situations, these aberrant alterations occur early in the formation of malignancy and appear to be tumour specific. Multiple reports have suggested that measurement of the methylation status of the promoter regions of specific genes can aid early detection of cancer, determine prognosis and predict therapy responses. Promising DNA methylation biomarkers include the use of methylated GSTP1 for aiding the early diagnosis of prostate cancer, methylated PITX2 for predicting outcome in lymph node-negative breast cancer patients and methylated MGMT in predicting benefit from alkylating agents in patients with glioblastomas. However, prior to clinical utilisation, these findings require validation in prospective clinical studies. Furthermore, assays for measuring gene methylation need to be standardised, simplified and evaluated in external quality assurance programmes. It is concluded that methylated genes have the potential to provide a new generation of cancer biomarkers.

  7. Aberrant methylation accounts for cell adhesion-related gene silencing during 3-methylcholanthrene and diethylnitrosamine induced multistep rat lung carcinogenesis associated with overexpression of DNA methyltransferases 1 and 3a

    To evaluate the significance of alterations in cell adhesion-related genes methylation during lung multistep carcinogenesis induced by the genotoxic carcinogens 3-methylcholanthrene (MCA) and diethylnitrosamine (DEN), tissue samples microdissected from MCA/DEN-induced rat lung carcinogenesis model were subjected to methylation-specific PCR to evaluate the DNA methylation status of CADM1, TIMP3, E-cadherin and N-cadherin. Immunohistochemistry was used to determine protein expression of CADM1, TIMP3, N-cadherin and the DNA methyltransferases (DNMTs) 1, 3a and 3b. E-cadherin hypermethylation was not detected in any tissue. CADM1, TIMP3 and N-cadherin hypermethylation was correlated with the loss of their protein expression during the progression of pathologic lesions. The prevalence of DNA methylation of at least one gene and the average number of methylated genes increased with the histological progression. DNMT1 and DNMT3a protein expression increased progressively during the stages of lung carcinogenesis, whereas DNMT3b overexpression was only found in several samples. Furthermore, DNMT1 protein expression levels were correlated with CADM1 methylation, and DNMT3a protein expression levels were correlated with CADM1, TIMP3 and N-cadherin methylation. The average number of methylated genes during carcinogenesis was significantly correlated with DNMT1 and DNMT3a protein expression levels. Moreover, mRNA expression of CADM1 significantly increased after treatment with DNMT inhibitor 5-aza-2'-deoxycytidine in CADM1-methylated primary tumor cell lines. Our findings suggest that an accumulation of hypermethylation accounts for cell adhesion-related gene silencing is associated with dynamic changes in the progression of MCA/DEN-induced rat lung carcinogenesis. We suggest that DNMT1 and DNMT3a protein overexpression may be responsible for this aberrant DNA methylation.

  8. Frequency of aberrant promoter methylation of p15INK4b and O6-methylguanine-DNA methyltransferase genes in b-cell non-Hodgkin lymphoma: A pilot study

    Kraguljac-Kurtović Nada

    2010-01-01

    Full Text Available The methylation status of the target promoter sequences of p15INK4B (p15 and O6-methylguanine-DNA methyltransferase (MGMT genes was studied by methylation-specific PCR in 10 adult patients with de novo B-cell non- Hodgkin lymphoma (B-NHL. The aberrant hypermethylation of the p15 gene was more frequent (50% compared to the hypermethylation of the MGMT gene (30%, and was detected in different types of B-NHL in both genes. Hypermethylation of the MGMT gene occurred exclusively in association with the hypermethylation of the p15 gene. All lymphoma patients with hypermethylation of the p15 and/or MGMT genes had a higher clinical stage of the disease (IV - V. We show the association of anemia and/or thrombocytopenia with the hypermethylation of the p15 gene, ascribing the p15 gene as a potential prognostic marker in B-NHL. Comethylation of MGMT with the p15 gene represents a novel finding and presents both genes as candidates for future studies of the hypermethylation profiles of B-NHL.

  9. Aberrant methylation of PCDH10 and RASSF1A genes in blood samples for non-invasive diagnosis and prognostic assessment of gastric cancer

    Pimson, Charinya; Pientong, Chamsai; Promthet, Supannee; Putthanachote, Nuntiput; Suwanrungruang, Krittika; Wiangnon, Surapon

    2016-01-01

    Background. Assessment of DNA methylation of specific genes is one approach to the diagnosis of cancer worldwide. Early stage detection is necessary to reduce the mortality rate of cancers, including those occurring in the stomach. For this purpose, tumor cells in circulating blood offer promising candidates for non-invasive diagnosis. Transcriptional inactivation of tumor suppressor genes, like PCDH10 and RASSF1A, by methylation is associated with progression of gastric cancer, and such methylation can therefore be utilized as a biomarker. Methods. The present research was conducted to evaluate DNA methylation in these two genes using blood samples of gastric cancer cases. Clinicopathological data were also analyzed and cumulative survival rates generated for comparison. Results. High frequencies of PCDH10 and RASSF1A methylations in the gastric cancer group were noted (94.1% and 83.2%, respectively, as compared to 2.97% and 5.45% in 202 matched controls). Most patients (53.4%) were in severe stage of the disease, with a median survival time of 8.4 months after diagnosis. Likewise, the patients with metastases, or RASSF1A and PCDH10 methylations, had median survival times of 7.3, 7.8, and 8.4 months, respectively. A Kaplan–Meier analysis showed that cumulative survival was significantly lower in those cases positive for methylation of RASSF1A than in their negative counterparts. Similarly, whereas almost 100% of patients positive for PCDH10 methylation had died after five years, none of the negative cases died over this period. Notably, the methylations of RASSF1A and PCDH10 were found to be higher in the late-stage patients and were also significantly correlated with metastasis and histology. Conclusions. PCDH10 and RASSF1A methylations in blood samples can serve as potential non-invasive diagnostic indicators in blood for gastric cancer. In addition to RASSF1A methylation, tumor stage proved to be a major prognostic factor in terms of survival rates.

  10. Aberrant DNA methylation in non-small cell lung cancer-associated fibroblasts

    Vizoso, Miguel; Puig, Marta; Carmona, F.Javier; Maqueda, María; Velásquez, Adriana; Gómez, Antonio; Labernadie, Anna; Lugo, Roberto; Gabasa, Marta; Rigat-Brugarolas, Luis G.; Trepat, Xavier; Ramírez, Josep; Moran, Sebastian; Vidal, Enrique; Reguart, Noemí; Perera, Alexandre; Esteller, Manel; Alcaraz, Jordi

    2015-01-01

    Epigenetic changes through altered DNA methylation have been implicated in critical aspects of tumor progression, and have been extensively studied in a variety of cancer types. In contrast, our current knowledge of the aberrant genomic DNA methylation in tumor-associated fibroblasts (TAFs) or other stromal cells that act as critical coconspirators of tumor progression is very scarce. To address this gap of knowledge, we conducted genome-wide DNA methylation profiling on lung TAFs and paired control fibroblasts (CFs) from non-small cell lung cancer patients using the HumanMethylation450 microarray. We found widespread DNA hypomethylation concomitant with focal gain of DNA methylation in TAFs compared to CFs. The aberrant DNA methylation landscape of TAFs had a global impact on gene expression and a selective impact on the TGF-β pathway. The latter included promoter hypermethylation-associated SMAD3 silencing, which was associated with hyperresponsiveness to exogenous TGF-β1 in terms of contractility and extracellular matrix deposition. In turn, activation of CFs with exogenous TGF-β1 partially mimicked the epigenetic alterations observed in TAFs, suggesting that TGF-β1 may be necessary but not sufficient to elicit such alterations. Moreover, integrated pathway-enrichment analyses of the DNA methylation alterations revealed that a fraction of TAFs may be bone marrow-derived fibrocytes. Finally, survival analyses using DNA methylation and gene expression datasets identified aberrant DNA methylation on the EDARADD promoter sequence as a prognostic factor in non-small cell lung cancer patients. Our findings shed light on the unique origin and molecular alterations underlying the aberrant phenotype of lung TAFs, and identify a stromal biomarker with potential clinical relevance. PMID:26449251

  11. Expression and aberrant promoter methylation of Wnt inhibitory factor-1 in human astrocytomas

    Wu Jun

    2010-03-01

    Full Text Available Abstract Background Wnt inhibitory factor-1(WIF-1 acts as a Wnt-antagonists and tumor suppressor, but hypermethylation of WIF-1 gene promoter and low expression activate Wnt signaling aberrantly and induce the development of various human tumors. With this work we intended to investigate the expression and promoter methylation status of WIF-1 gene in human astrocytomas. Methods The tissue samples consisted of 53 astrocytomas and 6 normal brain tissues. The expression levels of WIF-1 were determined by immunohistochemistry and semiquantitative RT-PCR. The results were analyzed in correlation with clinicopathological data. Methylation status of WIF-1 gene promoter was investigated using methylation specific PCR. The relationship between methylation and expression of the genes was analyzed. Results The average expression levels of WIF-1 protein and mRNA in astrocytomas were decreased significantly compared with normal control tissues. The protein and mRNA expression of WIF-1 gene in astrocytomas was decreased with the increase of pathological grade. Furthermore, WIF-1 promoter methylation was observed by MS-PCR in astrocytomas which showed significant reduction of WIF-1 expression. The WIF-1 promoter hypermethylation was associated with reduced expression of WIF-1 expression. Conclusion Our results demonstrate that the WIF-1 gene is frequently down-regulated or silenced in astrocytomas by aberrant promoter methylation. This may be an important mechanism in astrocytoma carcinogenesis.

  12. Aberrant methylation of N-methyl-D-aspartate receptor type 2B (NMDAR2B) in non-small cell carcinoma

    N-methyl-D-aspartate receptors (NMDAR) act as tumor suppressors of digestive malignancies. The expression and genetic methylation patterns of NMDAR2B in non-small cell lung cancer (NSCLC) are unknown. The relationship between gene methylation and expression of NMDAR2B was analyzed in NSCLC cell lines (N = 9) and clinical tissues (N = 216). The cell lines were studied using RT-PCR and 5-aza-2'-deoxycytidine treatment, while the clinical tissues were examined by methylation specific real-time quantitative PCR and immunohistochemistry. Retrospective investigation of patient records was used to determine the clinical significance of NMDAR2B methylation. NMDAR2B was silenced in five of the nine cell lines; 5-aza-2'-deoxycytidine treatment restored expression, and was inversely correlated with methylation. Aberrant methylation of NMDAR2B, detected in 61% (131/216) of clinical NSCLC tissues, was inversely correlated with the status of protein expression in 20 randomly examined tumors. Aberrant methylation was not associated with clinical factors such as gender, age, histological type, or TNM stage. However, aberrant methylation was an independent prognostic factor in squamous cell carcinoma cases. Aberrant methylation of the NMDAR2B gene is a common event in NSCLC. The prognosis was significantly better for cases of squamous cell carcinoma in which NMDAR2B was methylated. It may have different roles in different histological types

  13. Aberrant promoter CpG methylation and its translational applications in breast cancer

    Ting-Xiu Xiang; Ying Yuan; Li-Li Li; Zhao-Hui Wang; Liang-Ying Dan; Yan Chen; Guo-Sheng Ren; Qian Tao

    2013-01-01

    Breast cancer is a complex disease driven by multiple factors including both genetic and epigenetic alterations.Recent studies revealed that abnormal gene expression induced by epigenetic changes,including aberrant promoter methylation and histone modification,plays a critical role in human breast carcinogenesis.Silencing of tumor suppressor genes (TSGs) by promoter CpG methylation facilitates cells growth and survival advantages and further results in tumor initiation and progression,thus directly contributing to breast tumorigenesis.Usually,aberrant promoter methylation of TSGs,which can be reversed by pharmacological reagents,occurs at the early stage of tumorigenesis and therefore may serve as a potential tumor marker for early diagnosis and therapeutic targeting of breast cancer.In this review,we summarize the epigenetic changes of multiple TSGs involved in breast pathogenesis and their potential clinical applications as tumor markers for early detection and treatment of breast cancer.

  14. Expression and aberrant promoter methylation of Wnt inhibitory factor-1 in human astrocytomas

    Wu Jun; Liu Jinfang; Chen Fenghua; Fang Jiasheng; Wang Ying; Yang Zhuanyi; Wang Yanjin

    2010-01-01

    Abstract Background Wnt inhibitory factor-1(WIF-1) acts as a Wnt-antagonists and tumor suppressor, but hypermethylation of WIF-1 gene promoter and low expression activate Wnt signaling aberrantly and induce the development of various human tumors. With this work we intended to investigate the expression and promoter methylation status of WIF-1 gene in human astrocytomas. Methods The tissue samples consisted of 53 astrocytomas and 6 normal brain tissues. The expression levels of WIF-1 were det...

  15. Analysis of aberrant methylation on promoter sequences of tumor suppressor genes and total DNA in sputum samples: a promising tool for early detection of COPD and lung cancer in smokers

    Guzmán Leda

    2012-07-01

    Full Text Available Abstract Background Chronic obstructive pulmonary disease (COPD is a disorder associated to cigarette smoke and lung cancer (LC. Since epigenetic changes in oncogenes and tumor suppressor genes (TSGs are clearly important in the development of LC. In this study, we hypothesize that tobacco smokers are susceptible for methylation in the promoter region of TSGs in airway epithelial cells when compared with non-smoker subjects. The purpose of this study was to investigate the usefulness of detection of genes promoter methylation in sputum specimens, as a complementary tool to identify LC biomarkers among smokers with early COPD. Methods We determined the amount of DNA in induced sputum from patients with COPD (n = 23, LC (n = 26, as well as in healthy subjects (CTR (n = 33, using a commercial kit for DNA purification, followed by absorbance measurement at 260 nm. The frequency of CDKN2A, CDH1 and MGMT promoter methylation in the same groups was determined by methylation-specific polymerase chain reaction (MSP. The Fisher’s exact test was employed to compare frequency of results between different groups. Results DNA concentration was 7.4 and 5.8 times higher in LC and COPD compared to the (CTR (p  Conclusions We provide evidence that aberrant methylation of TSGs in samples of induced sputum is a useful tool for early diagnostic of lung diseases (LC and COPD in smoker subjects. Virtual slides The abstract MUST finish with the following text: Virtual Slides The virtual slide(s for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1127865005664160

  16. Aberrant DNA Methylation of rDNA and PRIMA1 in Borderline Personality Disorder.

    Teschler, Stefanie; Gotthardt, Julia; Dammann, Gerhard; Dammann, Reinhard H

    2016-01-01

    Borderline personality disorder (BPD) is a serious psychic disease with a high risk for suicide. DNA methylation is a hallmark for aberrant epigenetic regulation and could be involved in the etiology of BPD. Previously, it has been reported that increased DNA methylation of neuropsychiatric genes is found in the blood of patients with BPD compared to healthy controls. Here, we analyzed DNA methylation patterns of the ribosomal RNA gene (rDNA promoter region and 5'-external transcribed spacer/5'ETS) and the promoter of the proline rich membrane anchor 1 gene (PRIMA1) in peripheral blood samples of 24 female patients (mean age (33 ± 11) years) diagnosed with DSM-IV BPD and in 11 female controls (mean age (32 ± 7) years). A significant aberrant methylation of rDNA and PRIMA1 was revealed for BPD patients using pyrosequencing. For the promoter of PRIMA1, the average methylation of six CpG sites was 1.6-fold higher in BPD patients compared to controls. In contrast, the methylation levels of the rDNA promoter region and the 5'ETS were significantly lower (0.9-fold) in patients with BPD compared to controls. Thus, for nine CpGs located in the rDNA promoter region and for four CpGs at the 5'ETS decreased methylation was found in peripheral blood of patients compared to controls. Our results suggest that aberrant methylation of rDNA and PRIMA1 is associated with the pathogenesis of BPD. PMID:26742039

  17. Aberrant DNA Methylation of rDNA and PRIMA1 in Borderline Personality Disorder

    Stefanie Teschler

    2016-01-01

    Full Text Available Borderline personality disorder (BPD is a serious psychic disease with a high risk for suicide. DNA methylation is a hallmark for aberrant epigenetic regulation and could be involved in the etiology of BPD. Previously, it has been reported that increased DNA methylation of neuropsychiatric genes is found in the blood of patients with BPD compared to healthy controls. Here, we analyzed DNA methylation patterns of the ribosomal RNA gene (rDNA promoter region and 5′-external transcribed spacer/5′ETS and the promoter of the proline rich membrane anchor 1 gene (PRIMA1 in peripheral blood samples of 24 female patients (mean age (33 ± 11 years diagnosed with DSM-IV BPD and in 11 female controls (mean age (32 ± 7 years. A significant aberrant methylation of rDNA and PRIMA1 was revealed for BPD patients using pyrosequencing. For the promoter of PRIMA1, the average methylation of six CpG sites was 1.6-fold higher in BPD patients compared to controls. In contrast, the methylation levels of the rDNA promoter region and the 5′ETS were significantly lower (0.9-fold in patients with BPD compared to controls. Thus, for nine CpGs located in the rDNA promoter region and for four CpGs at the 5′ETS decreased methylation was found in peripheral blood of patients compared to controls. Our results suggest that aberrant methylation of rDNA and PRIMA1 is associated with the pathogenesis of BPD.

  18. Quantitative DNA Methylation Analysis of Candidate Genes in Cervical Cancer

    Erin M Siegel; Riggs, Bridget M; Delmas, Amber L.; Koch, Abby; Hakam, Ardeshir; Brown, Kevin D.

    2015-01-01

    Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and ...

  19. Comparative methylome analysis in solid tumors reveals aberrant methylation at chromosome 6p in nasopharyngeal carcinoma

    Altered patterns of DNA methylation are key features of cancer. Nasopharyngeal carcinoma (NPC) has the highest incidence in Southern China. Aberrant methylation at the promoter region of tumor suppressors is frequently reported in NPC; however, genome-wide methylation changes have not been comprehensively investigated. Therefore, we systematically analyzed methylome data in 25 primary NPC tumors and nontumor counterparts using a high-throughput approach with the Illumina HumanMethylation450 BeadChip. Comparatively, we examined the methylome data of 11 types of solid tumors collected by The Cancer Genome Atlas (TCGA). In NPC, the hypermethylation pattern was more dominant than hypomethylation and the majority of de novo methylated loci were within or close to CpG islands in tumors. The comparative methylome analysis reveals hypermethylation at chromosome 6p21.3 frequently occurred in NPC (false discovery rate; FDR=1.33 × 10−9), but was less obvious in other types of solid tumors except for prostate and Epstein–Barr virus (EBV)-positive gastric cancer (FDR<10−3). Bisulfite pyrosequencing results further confirmed the aberrant methylation at 6p in an additional patient cohort. Evident enrichment of the repressive mark H3K27me3 and active mark H3K4me3 derived from human embryonic stem cells were found at these regions, indicating both DNA methylation and histone modification function together, leading to epigenetic deregulation in NPC. Our study highlights the importance of epigenetic deregulation in NPC. Polycomb Complex 2 (PRC2), responsible for H3K27 trimethylation, is a promising therapeutic target. A key genomic region on 6p with aberrant methylation was identified. This region contains several important genes having potential use as biomarkers for NPC detection

  20. Small RNA-mediated DNA (cytosine-5) methyltransferase 1 inhibition leads to aberrant DNA methylation.

    Zhang, Guoqiang; Estève, Pierre-Olivier; Chin, Hang Gyeong; Terragni, Jolyon; Dai, Nan; Corrêa, Ivan R; Pradhan, Sriharsa

    2015-07-13

    Mammalian cells contain copious amounts of RNA including both coding and noncoding RNA (ncRNA). Generally the ncRNAs function to regulate gene expression at the transcriptional and post-transcriptional level. Among ncRNA, the long ncRNA and small ncRNA can affect histone modification, DNA methylation targeting and gene silencing. Here we show that endogenous DNA methyltransferase 1 (DNMT1) co-purifies with inhibitory ncRNAs. MicroRNAs (miRNAs) bind directly to DNMT1 with high affinity. The binding of miRNAs, such as miR-155-5p, leads to inhibition of DNMT1 enzyme activity. Exogenous miR-155-5p in cells induces aberrant DNA methylation of the genome, resulting in hypomethylation of low to moderately methylated regions. And small shift of hypermethylation of previously hypomethylated region was also observed. Furthermore, hypomethylation led to activation of genes. Based on these observations, overexpression of miR-155-5p resulted in aberrant DNA methylation by inhibiting DNMT1 activity, resulting in altered gene expression. PMID:25990724

  1. The role for oxidative stress in aberrant DNA methylation in Alzheimer's disease.

    Fleming, Jessica L; Phiel, Christopher J; Toland, Amanda Ewart

    2012-11-01

    Alzheimer's disease (AD) is a common, progressive neurodegenerative disorder without highly effective therapies. The etiology of AD is heterogeneous with amyloid-beta plaques, neurofibrillary tangles, oxidative stress, and aberrant DNA methylation all implicated in the disease pathogenesis. DNA methylation is a well-established process for regulating gene expression and has been found to regulate a growing number of important genes involved in AD development and progression. Additionally, aberrations in one-carbon metabolism are a common finding in AD patients with individuals exhibiting low S-adenosylmethionine and high homocysteine levels as well as low folate and vitamin B. Oxidative stress is considered one of the earliest events in AD pathogenesis and is thought to contribute largely to neuronal cell death. Emerging evidence suggests an interaction exists between oxidative stress and DNA methylation; however, the mechanism(s) remain unclear. This review summarizes known and potential genes implicated in AD that are regulated by DNA methylation and oxidative stress. We also highlight the evidence for the role of oxidative damage contributing to DNA hypomethylation in AD patients through several mechanisms as well as implications for disease understanding and therapeutic development. PMID:21605062

  2. Early aberrant DNA methylation events in a mouse model of acute myeloid leukemia

    Sonnet, Miriam; Claus, Rainer; Becker, Natalia; Zucknick, Manuela; Petersen, Jana; Lipka, Daniel B.; Oakes, Christopher C.; Andrulis, Mindaugas; Lier, Amelie; Milsom, Michael D.; Witte, Tania; Gu, Lei; Kim-Wanner, Soo-Zin; Schirmacher, Peter; Wulfert, Michael

    2014-01-01

    Background Aberrant DNA methylation is frequently found in human malignancies including acute myeloid leukemia (AML). While most studies focus on later disease stages, the onset of aberrant DNA methylation events and their dynamics during leukemic progression are largely unknown. Methods We screened genome-wide for aberrant CpG island methylation in three disease stages of a murine AML model that is driven by hypomorphic expression of the hematopoietic transcription factor PU.1. DNA methylati...

  3. The key culprit in the pathogenesis of systemic lupus erythematosus: Aberrant DNA methylation.

    Wu, Haijing; Zhao, Ming; Tan, Lina; Lu, Qianjin

    2016-07-01

    Systemic lupus erythematosus (SLE) is an autoimmune disease with multiple organ involvement. It is characterized by abundant autoantibodies that form immune complex with autoantigens and deposit in organs and cause tissue damage by inducing inflammation. The pathogenesis of SLE has been intensively studied but remains unclear. B and T lymphocyte abnormalities, dysregulation of apoptosis, defects in the clearance of apoptotic materials, and various genetic and epigenetic factors are believed to contribute to the initiation and development of SLE. The up-to-date research findings point to the relationship between abnormal DNA methylation and SLE, which has attracted considerable interest worldwide. Besides the global hypomethylation on lupus T and B cells, the gene specific and site-specific methylation has been identified and documented to be responsible for SLE. The purpose of this review was to present and summarize the association between aberrant DNA methylation of immune cells and SLE, the possible mechanisms of immune dysfunction caused by DNA methylation, and to better understand the roles of aberrant DNA methylation in the initiation and development of SLE and to provide an insight into the related diagnosis biomarkers and therapeutic options in SLE. PMID:26970492

  4. Aberrant DNA methylation of blood in schizophrenia by adjusting for estimated cellular proportions.

    Kinoshita, Makoto; Numata, Shusuke; Tajima, Atsushi; Ohi, Kazutaka; Hashimoto, Ryota; Shimodera, Shinji; Imoto, Issei; Takeda, Masatoshi; Ohmori, Tetsuro

    2014-12-01

    DNA methylation, which is the transference of a methyl group to the 5'-carbon position of the cytosine in a CpG dinucleotide, is one of the major mechanisms of epigenetic modifications. A number of studies have demonstrated altered DNA methylation of peripheral blood cells in schizophrenia (SCZ) in previous studies. However, most of these studies have been limited to the analysis of the CpG sites in CpG islands in gene promoter regions, and cell-type proportions of peripheral leukocytes, which may be one of the potential confounding factors for DNA methylation, have not been adjusted in these studies. In this study, we performed a genome-wide DNA methylation profiling of the peripheral leukocytes from patients with SCZ and from non-psychiatric controls (N = 105; 63 SCZ and 42 control subjects) using a quantitative high-resolution DNA methylation microarray which covered across the whole gene region (485,764 CpG dinucleotides). In the DNA methylation data analysis, we first estimated the cell-type proportions of each sample with a published algorithm. Next, we performed a surrogate variable analysis to identify potential confounding factors in our microarray data. Finally, we conducted a multiple linear regression analysis in consideration of these factors, including estimated cell-type proportions, and identified aberrant DNA methylation in SCZ at 2,552 CpG loci at a 5% false discovery rate correction. Our results suggest that altered DNA methylation may be involved in the pathophysiology of SCZ, and cell heterogeneity adjustments may be necessary for DNA methylation analysis. PMID:25052007

  5. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Erin M Siegel

    Full Text Available Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2. A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003. Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated.

  6. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Siegel, Erin M; Riggs, Bridget M; Delmas, Amber L; Koch, Abby; Hakam, Ardeshir; Brown, Kevin D

    2015-01-01

    Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2). A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site) per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC) of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003). Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated. PMID:25826459

  7. Aberrant promoter methylation of PPP1R3C and EFHD1 in plasma of colorectal cancer patients

    Aberrant DNA methylation is a common epigenetic alteration involved in colorectal cancer (CRC). In our previous study, we performed methylated DNA immunoprecipitation-on-chip analysis combined with gene re-expression analysis by 5-aza-2′-deoxycytidine treatment, to identify methylation genes in CRC genome widely. Among these genes, 12 genes showed aberrant hypermethylation frequently in >75% of 149 CRC samples but did not in normal samples. In this study, we aim to find out any of these methylation genes to be utilized for CRC detection using plasma DNA samples. Primers for methylation-specific PCR and pyrosequencing were designed for seven of the 12 genes. Among them, PPP1R3C and EFHD1 were rarely hypermethylated in peripheral blood cells, but frequently hypermethylated in 24 CRC tissue samples and their corresponding plasma samples. In plasma samples, PPP1R3C was methylated in 81% (97/120) of CRC patients, but only in 19% (18/96) of noncancer patients (P = 6 × 10−20, Fisher's exact test). In combined analysis with EFHD1, both genes were methylated in 53% (64/120) of CRC patients, but only in 4% (4/96) of noncancer patients (P = 2 × 10−16), giving high specificity of 96%. At least one of the two genes was methylated in 90% (108/120) of CRC patients, and 36% (35/96) of control patients, giving high sensitivity of 90%. Compared with low sensitivity of carcinoembryonic antigen (17% at stage I, 40% at stage II) and CA19-9 (0% at stage I, 13% at stage II) for early-stage CRCs, sensitivity of aberrant methylation was significantly higher: PPP1R3C methylation at 92% (11/12) for stage I and 77% (23/30) for stage II, and methylation of at least one gene at 100% (12/12) for stage I and 87% (26/30) for stage II. PPP1R3C methylation or its combined use of EFHD1 methylation was highly positive in CRC plasma samples, and they might be useful in detection of CRC, especially for early-stage CRCs

  8. Osteoponin Promoter Controlled by DNA Methylation: Aberrant Methylation in Cloned Porcine Genome

    Chih-Jie Shen

    2014-01-01

    Full Text Available Cloned animals usually exhibited many defects in physical characteristics or aberrant epigenetic reprogramming, especially in some important organ development. Osteoponin (OPN is an extracellular-matrix protein involved in heart and bone development and diseases. In this study, we investigated the correlation between OPN mRNA and its promoter methylation changes by the 5-aza-dc treatment in fibroblast cell and promoter assay. Aberrant methylation of porcine OPN was frequently found in different tissues of somatic nuclear transferred cloning pigs, and bisulfite sequence data suggested that the OPN promoter region −2615 to −2239 nucleotides (nt may be a crucial regulation DNA element. In pig ear fibroblast cell culture study, the demethylation of OPN promoter was found in dose-dependent response of 5-aza-dc treatment and followed the OPN mRNA reexpression. In cloned pig study, discrepant expression pattern was identified in several cloned pig tissues, especially in brain, heart, and ear. Promoter assay data revealed that four methylated CpG sites presenting in the −2615 to −2239 nt region cause significant downregulation of OPN promoter activity. These data suggested that methylation in the OPN promoter plays a crucial role in the regulation of OPN expression that we found in cloned pigs genome.

  9. Aberrant DNA Methylation: Implications in Racial Health Disparity.

    Xuefeng Wang

    Full Text Available Incidence and mortality rates of colorectal carcinoma (CRC are higher in African Americans (AAs than in Caucasian Americans (CAs. Deficient micronutrient intake due to dietary restrictions in racial/ethnic populations can alter genetic and molecular profiles leading to dysregulated methylation patterns and the inheritance of somatic to germline mutations.Total DNA and RNA samples of paired tumor and adjacent normal colon tissues were prepared from AA and CA CRC specimens. Reduced Representation Bisulfite Sequencing (RRBS and RNA sequencing were employed to evaluate total genome methylation of 5'-regulatory regions and dysregulation of gene expression, respectively. Robust analysis was conducted using a trimming-and-retrieving scheme for RRBS library mapping in conjunction with the BStool toolkit.DNA from the tumor of AA CRC patients, compared to adjacent normal tissues, contained 1,588 hypermethylated and 100 hypomethylated differentially methylated regions (DMRs. Whereas, 109 hypermethylated and 4 hypomethylated DMRs were observed in DNA from the tumor of CA CRC patients; representing a 14.6-fold and 25-fold change, respectively. Specifically; CHL1, 4 anti-inflammatory genes (i.e., NELL1, GDF1, ARHGEF4, and ITGA4, and 7 miRNAs (of which miR-9-3p and miR-124-3p have been implicated in CRC were hypermethylated in DNA samples from AA patients with CRC. From the same sample set, RNAseq analysis revealed 108 downregulated genes (including 14 ribosomal proteins and 34 upregulated genes (including POLR2B and CYP1B1 [targets of miR-124-3p] in AA patients with CRC versus CA patients.DNA methylation profile and/or products of its downstream targets could serve as biomarker(s addressing racial health disparity.

  10. Aberrant DNA Methylation: Implications in Racial Health Disparity

    Wang, Xuefeng; Ji, Ping; Zhang, Yuanhao; LaComb, Joseph F.; Tian, Xinyu; Li, Ellen; Williams, Jennie L.

    2016-01-01

    Background Incidence and mortality rates of colorectal carcinoma (CRC) are higher in African Americans (AAs) than in Caucasian Americans (CAs). Deficient micronutrient intake due to dietary restrictions in racial/ethnic populations can alter genetic and molecular profiles leading to dysregulated methylation patterns and the inheritance of somatic to germline mutations. Materials and Methods Total DNA and RNA samples of paired tumor and adjacent normal colon tissues were prepared from AA and CA CRC specimens. Reduced Representation Bisulfite Sequencing (RRBS) and RNA sequencing were employed to evaluate total genome methylation of 5’-regulatory regions and dysregulation of gene expression, respectively. Robust analysis was conducted using a trimming-and-retrieving scheme for RRBS library mapping in conjunction with the BStool toolkit. Results DNA from the tumor of AA CRC patients, compared to adjacent normal tissues, contained 1,588 hypermethylated and 100 hypomethylated differentially methylated regions (DMRs). Whereas, 109 hypermethylated and 4 hypomethylated DMRs were observed in DNA from the tumor of CA CRC patients; representing a 14.6-fold and 25-fold change, respectively. Specifically; CHL1, 4 anti-inflammatory genes (i.e., NELL1, GDF1, ARHGEF4, and ITGA4), and 7 miRNAs (of which miR-9-3p and miR-124-3p have been implicated in CRC) were hypermethylated in DNA samples from AA patients with CRC. From the same sample set, RNAseq analysis revealed 108 downregulated genes (including 14 ribosomal proteins) and 34 upregulated genes (including POLR2B and CYP1B1 [targets of miR-124-3p]) in AA patients with CRC versus CA patients. Conclusion DNA methylation profile and/or products of its downstream targets could serve as biomarker(s) addressing racial health disparity. PMID:27111221

  11. Hypermethylation and aberrant expression of secreted fizzled-related protein genes in pancreatic cancer

    Xian-Min Bu; Cheng-Hai Zhao; Ning Zhang; Feng Gao; Shuai Lin; Xian-Wei Dai

    2008-01-01

    AIM:To determine the methylation status and aberrant expression of some secreted frizzled-related protein (SFRP) genes in pancreatic cancer and explore their role in pancreatic carcinogenesis. METHODS:Methylation status and expression of SFRP genes were detected by methylation-specific PCR (MSPCR) and reverse-transcription PCR (RT-PCR) respectively. RESULTS:The frequencies of methylation for SFRP genes 1,2,4,5 were 70%, 48.3%,60% and 76.7% in pancreatic cancer samples, and 21.7%, 20%,10% and 36.7% in matched cancer adjacent normal tissue samples,respectively (χ2=28.23,P<0.0001 for SFRP gene 1; χ2=10.71,P=0.001 for SFRP gene 2;χ2=32.97,P<0.0001 for SFRP gene 4;χ2=19.55,P<0.0001 for SFRP gene 5). Expression loss of SFRP genes 1,2,4 and 5 was found in 65%,40%,55% and 71.7% of 60 pancreatic cancer samples, and 25%,15%,18.3% and 31.7% of matched cancer adjacent normal tissue samples,respectively (χ2=19.39,P<0.0001 for SFRP gene 1;χ2=9.40,P=0.002 for SFRP gene 2;χ2=17.37,P<0.0001 for SFRP gene 4;χ2=19.22,P<0.0001 for SFRP gene 5).SFRP gene 1 was methylated but not expressed in PC-3 and PANC-1,SFRP gene 2 was methylated but not expressed in PANC-1 and CFPAC-1,SFRP gene 4 was methylated but not expressed in PC-3,and SFRP gene 5 was methylated but not expressed in CFPAC-1. CONCLUSION:Hypermethylation and aberrant expression of SFRP genes are common in pancreatic cancer,which may be involved in pancreatic carcinogenesis.

  12. In silico analysis and DHPLC screening strategy identifies novel apoptotic gene targets of aberrant promoter hypermethylation in prostate cancer.

    Murphy, Therese M

    2011-01-01

    Aberrant DNA methylation has been implicated as a key survival mechanism in cancer, whereby promoter hypermethylation silences genes essential for many cellular processes including apoptosis. Limited data is available on the methylation profile of apoptotic genes in prostate cancer (CaP). The aim of this study was to profile methylation of apoptotic-related genes in CaP using denaturing high performance liquid chromatography (DHPLC).

  13. High-throughput detection of aberrant imprint methylation in the ovarian cancer by the bisulphite PCR-Luminex method

    Hiura Hitoshi

    2012-03-01

    Full Text Available Abstract Background Aberrant DNA methylation leads to loss of heterozygosity (LOH or loss of imprinting (LOI as the first hit during human carcinogenesis. Recently we developed a new high-throughput, high-resolution DNA methylation analysis method, bisulphite PCR-Luminex (BPL, using sperm DNA and demonstrated the effectiveness of this novel approach in rapidly identifying methylation errors. Results In the current study, we applied the BPL method to the analysis of DNA methylation for identification of prognostic panels of DNA methylation cancer biomarkers of imprinted genes. We found that the BPL method precisely quantified the methylation status of specific DNA regions in somatic cells. We found a higher frequency of LOI than LOH. LOI at IGF2, PEG1 and H19 were frequent alterations, with a tendency to show a more hypermethylated state. We detected changes in DNA methylation as an early event in ovarian cancer. The degree of LOI (LOH was associated with altered DNA methylation at IGF2/H19 and PEG1. Conclusions The relative ease of BPL method provides a practical method for use within a clinical setting. We suggest that DNA methylation of H19 and PEG1 differentially methylated regions (DMRs may provide novel biomarkers useful for screening, diagnosis and, potentially, for improving the clinical management of women with human ovarian cancer.

  14. Identification of candidate methylation-responsive genes in ovarian cancer

    Dickerson Erin B

    2007-01-01

    Full Text Available Abstract Background Aberrant methylation of gene promoter regions has been linked to changes in gene expression in cancer development and progression. Genes associated with CpG islands (CGIs are especially prone to methylation, but not all CGI-associated genes display changes in methylation patterns in cancers. Results In order to identify genes subject to regulation by methylation, we conducted gene expression profile analyses of an ovarian cancer cell line (OVCAR-3 before and after treatment with the demethylating agent 5-aza-deoxycytidine (5-aza-dC. An overlapping subset of these genes was found to display significant differences in gene expression between normal ovarian surface epithelial cells and malignant cells isolated from ovarian carcinomas. While 40% of all human genes are associated with CGIs, > 94% of the overlapping subset of genes is associated with CGIs. The predicted change in methylation status of genes randomly selected from the overlapping subset was experimentally verified. Conclusion We conclude that correlating genes that are upregulated in response to 5-aza-dC treatment of cancer cell lines with genes that are down-regulated in cancer cells may be a useful method to identify genes experiencing epigenetic-mediated changes in expression over cancer development.

  15. MIR-9-1 ABERRANT METHYLATION IS A FREQUENT EVENT IN BREAST CANCER AND IS ASSOCIATED WITH BONE METASTASES

    Anca Florescu

    2012-03-01

    Full Text Available Abstract:Background. Aberrant promoter methylation of classical tumor suppressor genes occurs frequently during carcinogenesis. Several lines of evidences suggest that this epigenetic change also regulates microRNAs expression and may represent a potential molecular marker for cancer.Methods. We examined the methylation status at the hsa-miR-9-1 gene promoter in a series of 66 breast cancer cases by methylation sensitive PCR (MSP analysis. For 43 of the 66 patients paired normal breast tissue and/or pre invasive (ADH, DCIS lesions were also available. As control methylation status was determined on 6 normal breast tissues obtained from reductive mammoplasty.  Results. Methylation at mir-9-1 gene was detected in 32 out of 66 breast tumours (49% and in none of the 6 normal breast tissues derived from reductive mammoplasty (P=0.02 χ2- Test. In all cases the same methylation status was demonstrated in tumour specimen, paired normal breast tissues and/or pre-invasive (ADH and DCIS lesions. An higher frequency of methylation was found in patients showing metastases at diagnosis as compared with non metastatic patients (P=0.03 χ2-Test. Moreover, methylation at mir-9-1 gene was more frequent in patients showing bone metastases as first metastatic sites (P=0.04 χ2-Test, and in the subgroup of patients developing only bone metastases as compared with patients developing metastases  to visceral organs (P=0.03 χ2-Test.Conclusions. This study give further evidence of epigenetic mechanisms as regulators of miR-9 expression in breast cancer. Moreover, our results suggest an association between hypermethylation  at the miR-9-1 gene and metastatic site.

  16. Aberrant DNA methylation patterns in cultured mouse embryos

    HOU Jian; CUI Xiuhong; LEI Tinghua; LIU Lei; AN Xiaorong; CHEN Yongfu

    2005-01-01

    Mouse early embryos undergo genome-wide demethylation and remethylation events during pre-implantation development. Abnormal methylation reprogramming is thought to be associated with development arrest. Using immunofiuorescence staining with an antibody against 5-methylcytosine (MeC), we examined the genome methylation patterns of mouse embryos cultured in vitro. The results did not show the difference in staining patterns between development-blocked two-cell embryos that cultured in vitro and the two-cell embryos that were freshly collected from the donor mice. But in vitro-arrested morulae displayed a strong positive staining when compared to the morulae freshly collected from the donor mice. At the blastocyst stage, although most embryos showed the expected methylation patterns, with highly stained inner cell mass (ICM) and weekly stained trophectoderm (TE), a proportion of embryos were dimly stained in both ICM and TE. These results indicated that the methylation profile of the embryos could be changed by culturing in vitro when the embryos were in the transition from morulae to blastocyst.

  17. Aberrant epigenetic changes and gene expression in cloned cattle dying around birth

    Zhao Dingsheng

    2008-02-01

    Full Text Available Abstract Background Aberrant reprogramming of donor somatic cell nuclei may result in many severe problems in animal cloning. To assess the extent of abnormal epigenetic modifications and gene expression in clones, we simultaneously examined DNA methylation, histone H4 acetylation and expression of six genes (β-actin, VEGF, oct4, TERT, H19 and Igf2 and a repetitive sequence (art2 in five organs (heart, liver, spleen, lung and kidney from two cloned cattle groups that had died at different stages. In the ED group (early death, n = 3, the cloned cattle died in the perinatal period. The cattle in the LD group (late death, n = 3 died after the perinatal period. Normally reproduced cattle served as a control group (n = 3. Results Aberrant DNA methylation, histone H4 acetylation and gene expression were observed in both cloned groups. The ED group showed relatively fewer severe DNA methylation abnormalities (p Conclusion Deaths of clones may be ascribed to abnormal expression of a very limited number of genes.

  18. Aberrant Vimentin DNA Methylation in Stool — EDRN Public Portal

    The VIM gene encodes a member of the intermediate filament family. VIM proteins are class-III intermediate filaments found in various non-epithelial cells, especially mesenchymal cells. These intermediate filaments, along with microtubules and actin microfilaments, make up the cytoskeleton.

  19. Genes suppressed by DNA methylation in non-small cell lung cancer reveal the epigenetics of epithelial-mesenchymal transition.

    Lin, Steven; Wang, Jing; Saintigny, Pierre; Wu, Chia-Chin; Giri, Uma; Jing ZHANG; Menju, Toshi; Diao, Lixia; Byers, Lauren; Weinstein, John ,; Coombes, Kevin; Girard, Luc; Komaki, Ritsuko; Wistuba, Ignacio; Date, Hiroshi

    2013-01-01

    Background DNA methylation is associated with aberrant gene expression in cancer, and has been shown to correlate with therapeutic response and disease prognosis in some types of cancer. We sought to investigate the biological significance of DNA methylation in lung cancer. Results We integrated the gene expression profiles and data of gene promoter methylation for a large panel of non-small cell lung cancer cell lines, and identified 578 candidate genes with expression levels that were inver...

  20. Aberrant septin 9 DNA methylation in colorectal cancer is restricted to a single CpG island

    The septin 9 gene (SEPT9) codes for a GTP-binding protein associated with filamentous structures and cytoskeleton formation. SEPT9 plays a role in multiple cancers as either an oncogene or a tumor suppressor gene. Regulation of SEPT9 expression is complex and not well understood; however, hypermethylation of the gene was recently introduced as a biomarker for early detection of colorectal cancer (CRC) and has been linked to cancer of the breast and of the head and neck. Because the DNA methylation landscape of different regions of SEPT9 is poorly understood in cancer, we analyzed the methylation patterns of this gene in distinct cell populations from normal and diseased colon mucosa. Laser capture microdissection was performed to obtain homogeneous populations of epithelial and stromal cells from normal, adenomatous, and tumorous colon mucosa. Microdissected samples were analyzed using direct bisulfite sequencing to determine the DNA methylation status of eight regions within and near the SEPT9 gene. Septin-9 protein expression was assessed using immunohistochemistry (IHC). Regions analyzed in SEPT9 were unmethylated in normal tissue except for a methylation boundary detected downstream of the largest CpG island. In adenoma and tumor tissues, epithelial cells displayed markedly increased DNA methylation levels (>80%, p <0.0001) in only one of the CpG islands investigated. SEPT9 methylation in stromal cells increased in adenomatous and tumor tissues (≤50%, p <0.0001); however, methylation did not increase in stromal cells of normal tissue close to the tumor. IHC data indicated a significant decrease (p <0.01) in Septin-9 protein levels in epithelial cells derived from adenoma and tumor tissues; Septin-9 protein levels in stromal cells were low in all tissues. Hypermethylation of SEPT9 in adenoma and CRC specimens is confined to one of several CpG islands of this gene. Tumor-associated aberrant methylation originates in epithelial cells; stromal cells appear to

  1. Aberrant Gene Expression in Acute Myeloid Leukaemia

    Bagger, Frederik Otzen

    Summary Acute Myeloid Leukaemia (AML) is an aggressive cancer of the bone marrow, affecting formation of blood cells during haematopoiesis. This thesis presents investigation of AML using mRNA gene expression profiles (GEP) of samples extracted from the bone marrow of healthy and diseased subjects...

  2. Methylated genes as new cancer biomarkers

    Brunner, Nils; Duffy, M.J; Napieralski, R.;

    2009-01-01

    measurement of the methylation status of the promoter regions of specific genes can aid early detection of cancer, determine prognosis and predict therapy responses. Promising DNA methylation biomarkers include the use of methylated GSTP1 for aiding the early diagnosis of prostate cancer, methylated PITX2 for...... predicting outcome in lymph node-negative breast cancer patients and methylated MGMT in predicting benefit from alkylating agents in patients with glioblastomas. However, prior to clinical utilisation, these findings require validation in prospective clinical studies. Furthermore, assays for measuring gene...

  3. A novel method for detecting 7-methyl guanine reveals aberrant methylation levels in Huntington disease

    Thomas, Beena; Matson, Samantha; Chopra, Vanita; Sun, Liping; Sharma, Swati; Hersch, Steven; Rosas, H. Diana; Scherzer, Clemens; Ferrante, Robert; Matson, Wayne

    2013-01-01

    Guanine methylation is a ubiquitous process affecting DNA and various RNA species. N-7 guanine methylation (7-MG), though relatively less studied, could have a significant role in normal transcriptional regulation as well as in the onset and development of pathological conditions. The lack of a sensitive method to accurately quantify trace amounts of altered bases like 7-MG, has been a major deterrent in delineating its biological function(s). Here we report the development of methods to dete...

  4. ∆DNMT3B4-del Contributes to Aberrant DNA Methylation Patterns in Lung Tumorigenesis

    Mark Z. Ma

    2015-10-01

    Full Text Available Aberrant DNA methylation is a hallmark of cancer but mechanisms contributing to the abnormality remain elusive. We have previously shown that ∆DNMT3B is the predominantly expressed form of DNMT3B. In this study, we found that most of the lung cancer cell lines tested predominantly expressed DNMT3B isoforms without exons 21, 22 or both 21 and 22 (a region corresponding to the enzymatic domain of DNMT3B termed DNMT3B/∆DNMT3B-del. In normal bronchial epithelial cells, DNMT3B/ΔDNMT3B and DNMT3B/∆DNMT3B-del displayed equal levels of expression. In contrast, in patients with non-small cell lung cancer NSCLC, 111 (93% of the 119 tumors predominantly expressed DNMT3B/ΔDNMT3B-del, including 47 (39% tumors with no detectable DNMT3B/∆DNMT3B. Using a transgenic mouse model, we further demonstrated the biological impact of ∆DNMT3B4-del, the ∆DNMT3B-del isoform most abundantly expressed in NSCLC, in global DNA methylation patterns and lung tumorigenesis. Expression of ∆DNMT3B4-del in the mouse lungs resulted in an increased global DNA hypomethylation, focal DNA hypermethylation, epithelial hyperplastia and tumor formation when challenged with a tobacco carcinogen. Our results demonstrate ∆DNMT3B4-del as a critical factor in developing aberrant DNA methylation patterns during lung tumorigenesis and suggest that ∆DNMT3B4-del may be a target for lung cancer prevention.

  5. Relationship between promoter methylation & tissue expression of MGMT gene in ovarian cancer

    V Shilpa; Rahul Bhagat; C S Premalata; V R Pallavi; Ramesh, G.; Lakshmi Krishnamoorthy

    2014-01-01

    Background & objectives: Epigenetic alterations, in addition to multiple gene abnormalities, are involved in the genesis and progression of human cancers. Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumour suppressor genes. O 6 -methyguanine-DNA methyltransferase (MGMT) is a DNA repair gene that removes mutagenic and cytotoxic adducts from the O 6 -position of guanine induced by alkylating agents. MGMT promoter hyperme...

  6. Aberrant promoter methylation and expression of UTF1 during cervical carcinogenesis.

    Samuel Guenin

    Full Text Available Promoter methylation profiles are proposed as potential prognosis and/or diagnosis biomarkers in cervical cancer. Up to now, little is known about the promoter methylation profile and expression pattern of stem cell (SC markers during tumor development. In this study, we were interested to identify SC genes methylation profiles during cervical carcinogenesis. A genome-wide promoter methylation screening revealed a strong hypermethylation of Undifferentiated cell Transcription Factor 1 (UTF1 promoter in cervical cancer in comparison with normal ectocervix. By direct bisulfite pyrosequencing of DNA isolated from liquid-based cytological samples, we showed that UTF1 promoter methylation increases with lesion severity, the highest level of methylation being found in carcinoma. This hypermethylation was associated with increased UTF1 mRNA and protein expression. By using quantitative RT-PCR and Western Blot, we showed that both UTF1 mRNA and protein are present in epithelial cancer cell lines, even in the absence of its two main described regulators Oct4A and Sox2. Moreover, by immunofluorescence, we confirmed the nuclear localisation of UTF1 in cell lines. Surprisingly, direct bisulfite pyrosequencing revealed that the inhibition of DNA methyltransferase by 5-aza-2'-deoxycytidine was associated with decreased UTF1 gene methylation and expression in two cervical cancer cell lines of the four tested. These findings strongly suggest that UTF1 promoter methylation profile might be a useful biomarker for cervical cancer diagnosis and raise the questions of its role during epithelial carcinogenesis and of the mechanisms regulating its expression.

  7. Aberrant methylation of Polo-like kinase CpG islands in Plk4 heterozygous mice

    Shum David

    2011-02-01

    Full Text Available Abstract Background Hepatocellular carcinoma (HCC, one of the most common cancers world-wide occurs twice as often in men compared to women. Predisposing conditions such as alcoholism, chronic viral hepatitis, aflatoxin B1 ingestion, and cirrhosis all contribute to the development of HCC. Methods We used a combination of methylation specific PCR and bisulfite sequencing, qReal-Time PCR (qPCR, and Western blot analysis to examine epigenetic changes for the Polo-like kinases (Plks during the development of hepatocellular carcinoma (HCC in Plk4 heterozygous mice and murine embryonic fibroblasts (MEFs. Results Here we report that the promoter methylation of Plk4 CpG islands increases with age, was more prevalent in males and that Plk4 epigenetic modification and subsequent downregulation of expression was associated with the development of HCC in Plk4 mutant mice. Interestingly, the opposite occurs with another Plk family member, Plk1 which was typically hypermethylated in normal liver tissue but became hypomethylated and upregulated in liver tumours. Furthermore, upon alcohol exposure murine embryonic fibroblasts exhibited increased Plk4 hypermethylation and downregulation along with increased centrosome numbers and multinucleation. Conclusions These results suggest that aberrant Plk methylation is correlated with the development of HCC in mice.

  8. The influence of anthracosis and p16ink4a gene abberant methylation to the oncogenesis and progression of small pulmonary adenocarcinoma

    Daye WANG

    2008-08-01

    Full Text Available Background and objective Anthracosis is black dust matter deposition in the pulmonary parenchyma, which can cause bronchial deformity and destruction. Previously reported, anthracosis is closely correlated to the oncogenesis and progression of small pulmonary adenocarcinoma and p16ink4a gene aberrant methylation was closely associated with lung carcinogenesis. In this study, we want to characterize the influence of anthracosis and p16ink4a gene aberrant methylation on small adenocarcinoma. Methods DNA was bisulfite modified and then Methylation Specific PCR was used to detect p16ink4a gene aberrant methylation, and black dust matter was extracted from lung tissues, the absolute absorbance (A detected by densitometry was defined as anthracotic index (AI. The histopathologic diagnosis was according to Noguchi's classification for small pulmonary adenocarcinoma. Results For heavy smokers, the mean AI was significantly higher than that of nonsmokers (P=0.005 and the frequency of p16ink4a gene aberrant methylation was also significantly higher than that of nonsmokers (P=0.023. The frequency of p16ink4a gene aberrant methylation of early stage small adenocarcinoma was lower than that of advanced and poor differentiated small adenocarcinoma, otherwise p16ink4a protein expression of early stage small adenocarcinoma was significantly higher than that of poor differentiated small adenocarcinoma (P=0.032. Conclusion AI and p16ink4a gene aberrant methylation detection could be used as a combined potential biomarker of small adenocarcinoma.  

  9. Genomic aberrations frequently alter chromatin regulatory genes in chordoma.

    Wang, Lu; Zehir, Ahmet; Nafa, Khedoudja; Zhou, Nengyi; Berger, Michael F; Casanova, Jacklyn; Sadowska, Justyna; Lu, Chao; Allis, C David; Gounder, Mrinal; Chandhanayingyong, Chandhanarat; Ladanyi, Marc; Boland, Patrick J; Hameed, Meera

    2016-07-01

    Chordoma is a rare primary bone neoplasm that is resistant to standard chemotherapies. Despite aggressive surgical management, local recurrence and metastasis is not uncommon. To identify the specific genetic aberrations that play key roles in chordoma pathogenesis, we utilized a genome-wide high-resolution SNP-array and next generation sequencing (NGS)-based molecular profiling platform to study 24 patient samples with typical histopathologic features of chordoma. Matching normal tissues were available for 16 samples. SNP-array analysis revealed nonrandom copy number losses across the genome, frequently involving 3, 9p, 1p, 14, 10, and 13. In contrast, copy number gain is uncommon in chordomas. Two minimum deleted regions were observed on 3p within a ∼8 Mb segment at 3p21.1-p21.31, which overlaps SETD2, BAP1 and PBRM1. The minimum deleted region on 9p was mapped to CDKN2A locus at 9p21.3, and homozygous deletion of CDKN2A was detected in 5/22 chordomas (∼23%). NGS-based molecular profiling demonstrated an extremely low level of mutation rate in chordomas, with an average of 0.5 mutations per sample for the 16 cases with matched normal. When the mutated genes were grouped based on molecular functions, many of the mutation events (∼40%) were found in chromatin regulatory genes. The combined copy number and mutation profiling revealed that SETD2 is the single gene affected most frequently in chordomas, either by deletion or by mutations. Our study demonstrated that chordoma belongs to the C-class (copy number changes) tumors whose oncogenic signature is non-random multiple copy number losses across the genome and genomic aberrations frequently alter chromatin regulatory genes. © 2016 Wiley Periodicals, Inc. PMID:27072194

  10. The Aberrant DNA Methylation Profile of Human Induced Pluripotent Stem Cells Is Connected to the Reprogramming Process and Is Normalized During In Vitro Culture.

    Lenka Tesarova

    Full Text Available The potential clinical applications of human induced pluripotent stem cells (hiPSCs are limited by genetic and epigenetic variations among hiPSC lines and the question of their equivalency with human embryonic stem cells (hESCs. We used MethylScreen technology to determine the DNA methylation profile of pluripotency and differentiation markers in hiPSC lines from different source cell types compared to hESCs and hiPSC source cells. After derivation, hiPSC lines compromised a heterogeneous population characterized by variable levels of aberrant DNA methylation. These aberrations were induced during somatic cell reprogramming and their levels were associated with the type of hiPSC source cells. hiPSC population heterogeneity was reduced during prolonged culture and hiPSCs acquired an hESC-like methylation profile. In contrast, the expression of differentiation marker genes in hiPSC lines remained distinguishable from that in hESCs. Taken together, in vitro culture facilitates hiPSC acquisition of hESC epigenetic characteristics. However, differences remain between both pluripotent stem cell types, which must be considered before their use in downstream applications.

  11. Increased DNA methylation of neuropsychiatric genes occurs in borderline personality disorder.

    Dammann, Gerhard; Teschler, Stefanie; Haag, Tanja; Altmüller, Franziska; Tuczek, Frederik; Dammann, Reinhard H

    2011-12-01

    Borderline personality disorder (BPD) is a complex psychiatric disease of increasing importance. Epigenetic alterations are hallmarks for altered gene expression and could be involved in the etiology of BPD. In our study we analyzed DNA methylation patterns of 14 neuropsychiatric genes (COMT, DAT1, GABRA1, GNB3, GRIN2B, HTR1B, HTR2A, 5-HTT, MAOA, MAOB, NOS1, NR3C1, TPH1 and TH). DNA methylation was analyzed by bisulfite restriction analysis and pyrosequencing in whole blood samples of patients diagnosed with DSM-IV BPD and in controls. Aberrant methylation was not detectable using bisulfite restriction analysis, but a significantly increased methylation of HTR2A, NR3C1, MAOA, MAOB and soluble COMT (S-COMT) was revealed for BPD patients using pyrosequencing. For HTR2A the average methylation of four CpG sites was 0.8% higher in BPD patients compared to controls (p = 0.002). The average methylation of NR3C1 was 1.8% increased in BPD patients compared to controls (p = 0.0003) and was higher at 2 out of 8 CpGs (p ≤ 0.04). In females, an increased average methylation (1.5%) of MAOA was observed in BPD patients compared to controls (p = 0.046). A similar trend (1.4% higher methylation) was observed for MAOB in female BPD patients and increased methylation was significant for 1 out of 6 CpG sites. For S-COMT, a higher methylation of 2 out of 4 CpG sites was revealed in BPD patients (p ≤ 0.02). In summary, methylation signatures of several promoter regions were established and a significant increased average methylation (1.7%) occurred in blood samples of BPD patients (p < 0.0001). Our data suggest that aberrant epigenetic regulation of neuropsychiatric genes may contribute to the pathogenesis of BPD. PMID:22139575

  12. The induction of SCE and chromosomal aberrations with relation to specific base methylation of DNA in Chinese hamster cells by N-methyl-N-nitrosourea and dimethyl sulphate.

    Connell, J R; Medcalf, A S

    1982-01-01

    Chinese hamster cells (V79) were treated, either as exponentially proliferating cultures or under conditions where they were density-inhibited, with various doses of the potent carcinogen N-methyl-N-nitrosourea (MNU) or the relatively weak carcinogen dimethylsulphate (DMS). The colony forming ability of these cells and the induced frequencies of sister chromatid exchanges (SCEs) and chromosomal aberrations were assayed. Following the exposure of density-inhibited cells to radio-labelled methylating agents (labelled in the methyl group) these phenomena were related to the levels of 7-methylguanine (7-meGua), O6-methylguanine (O6-meGua) and 3-methyladenine (3-me-Ade) in the DNA. At equitoxic doses MNU and DMS induced similar frequencies of SCEs and chromosomal aberrations. Since, at equitoxic doses, MNU produces approximately 20 times more O6-meGua in V79 cell DNA than does DMS, this indicates that the formation of O6-meGua in DNA is not a major cause of SCEs and chromosomal aberrations. DMS-induced SCEs may be mediated via the production of both 3-meAde and 7-meGua in the DNA; these two methylated purines may also be responsible for MNU-induced SCEs. Therefore, no one specific methylated purine was identified as being solely accountable for the formation of SCEs. Also, the repair of lesions in the DNA of non-replicating V79 cells leads to a reduction in the SCE frequency on their subsequent release from the density-inhibited state, suggesting that repair is not intimately responsible for their formation. No association was discernable between chromosomal aberrations and any of the three methylated purines studied. PMID:7094205

  13. DNA Methylation in exon 1 of CDKN2A gene in formalin-fixed, paraffin-embedded colon cancer samples

    Hossein Faramarzi

    2015-04-01

    Conclusion: The result of this study has been confirmed the role of CDKN2A gene promoter methylation of CpG sites of colorectal cancer as the leading cause of colorectal cancer. These data suggest that epigenetic silencing via aberrant methylation of the CDKN2A promoter plays a critical role in the inactivation of this tumor suppressor gene in colorectal cancer and can be used as a marker for early detection and identification of potential applications.

  14. Small RNA-mediated DNA (cytosine-5) methyltransferase 1 inhibition leads to aberrant DNA methylation

    Zhang, Guoqiang; Estève, Pierre-Olivier; Chin, Hang Gyeong; Terragni, Jolyon; Dai, Nan; Corrêa, Ivan R.; Pradhan, Sriharsa

    2015-01-01

    Mammalian cells contain copious amounts of RNA including both coding and noncoding RNA (ncRNA). Generally the ncRNAs function to regulate gene expression at the transcriptional and post-transcriptional level. Among ncRNA, the long ncRNA and small ncRNA can affect histone modification, DNA methylation targeting and gene silencing. Here we show that endogenous DNA methyltransferase 1 (DNMT1) co-purifies with inhibitory ncRNAs. MicroRNAs (miRNAs) bind directly to DNMT1 with high affinity. The bi...

  15. Aberrant methylation frequency of TNFRSF10C promoter in pancreatic cancer cell lines

    Hui-Hua Cai; Yue-Ming Sun; Yi Miao; Wen-Tao Gao; Quan Peng; JieYao; Han-Lin Zhao

    2011-01-01

    BACKGROUND: A growing body of evidence suggests that many tumors are initiated by both epigenetic abnormalities and gene mutations, which promote tumor progression. Epigenetic abnormalities include changes in DNA methylation and in the modification of histones. This study aimed to assess the status of methylation in the CpG island (CGI) of the tumor necrosis factor receptor superfamily member 10c (TNFRSF10C) with combined bisulfite restriction analysis (COBRA) and to evaluate its role in the progression of pancreatic cancer (PC). METHODS: The methylation status of four PC cell lines was assessed using COBRA and/or bisulfite genomic sequencing (BGS). Changes in methylation and TNFRSF10C expression in PC cell lines before and after treatment with 5-aza-2'-deoxycytidine (5-aza-dC) and/or trichostatin A (TSA) were assessed by BGS and real-time RT-PCR. Apoptosis in the four cell lines was tested by flow cytometry (FCM) and TUNEL assay. RESULTS: The methylation status of the TNFRSF10C promoter was assessed in PC cells (BxPC-3: 68.84±8.71%; CFPAC-1: 0;PANC-1: 96.77±4.57%; SW1990: 54.97±7.33%) with the COBRA assay, which was confirmed by the results of BGS. After treatment with 5-aza-dC and/or TSA, apoptosis was induced in PC cells to different degrees, and the levels of TNFRSF10C transcriptional expression in the PC cell lines (except CFPAC-1) increased markedly after 5-aza-dC treatment. CONCLUSIONS: A high frequency of CGI methylation in the TNFRSF10C promoter results in inactivation of the gene and enhancement of tumor growth in most PC cell lines (except CFPAC-1). Inactivation of TNFRSF10C by CGI hypermethylation can play an important role in PC progression and be potentially useful as a diagnostic marker and a new therapeutic approach for PC.

  16. Integrative DNA methylation and gene expression analyses identify DNA packaging and epigenetic regulatory genes associated with low motility sperm.

    Sara E Pacheco

    Full Text Available BACKGROUND: In previous studies using candidate gene approaches, low sperm count (oligospermia has been associated with altered sperm mRNA content and DNA methylation in both imprinted and non-imprinted genes. We performed a genome-wide analysis of sperm DNA methylation and mRNA content to test for associations with sperm function. METHODS AND RESULTS: Sperm DNA and mRNA were isolated from 21 men with a range of semen parameters presenting to a tertiary male reproductive health clinic. DNA methylation was measured with the Illumina Infinium array at 27,578 CpG loci. Unsupervised clustering of methylation data differentiated the 21 sperm samples by their motility values. Recursively partitioned mixture modeling (RPMM of methylation data resulted in four distinct methylation profiles that were significantly associated with sperm motility (P = 0.01. Linear models of microarray analysis (LIMMA was performed based on motility and identified 9,189 CpG loci with significantly altered methylation (Q<0.05 in the low motility samples. In addition, the majority of these disrupted CpG loci (80% were hypomethylated. Of the aberrantly methylated CpGs, 194 were associated with imprinted genes and were almost equally distributed into hypermethylated (predominantly paternally expressed and hypomethylated (predominantly maternally expressed groups. Sperm mRNA was measured with the Human Gene 1.0 ST Affymetrix GeneChip Array. LIMMA analysis identified 20 candidate transcripts as differentially present in low motility sperm, including HDAC1 (NCBI 3065, SIRT3 (NCBI 23410, and DNMT3A (NCBI 1788. There was a trend among altered expression of these epigenetic regulatory genes and RPMM DNA methylation class. CONCLUSIONS: Using integrative genome-wide approaches we identified CpG methylation profiles and mRNA alterations associated with low sperm motility.

  17. Multiplexed methylation profiles of tumor suppressor genes and clinical outcome in lung cancer

    Venditti Julio

    2010-09-01

    Full Text Available Abstract Background Changes in DNA methylation of crucial cancer genes including tumor suppressors can occur early in carcinogenesis, being potentially important early indicators of cancer. The objective of this study was to examine a multiplexed approach to assess the methylation of tumor suppressor genes as tumor stratification and clinical outcome prognostic biomarkers for lung cancer. Methods A multicandidate probe panel interrogated DNA for aberrant methylation status in 18 tumor suppressor genes in lung cancer using a methylation-specific multiplex ligation-dependent probe amplification assay (MS-MLPA. Lung cancer cell lines (n = 7, and primary lung tumors (n = 54 were examined using MS-MLPA. Results Genes frequently methylated in lung cancer cell lines including SCGB3A1, ID4, CCND2 were found among the most commonly methylated in the lung tumors analyzed. HLTF, BNIP3, H2AFX, CACNA1G, TGIF, ID4 and CACNA1A were identified as novel tumor suppressor candidates methylated in lung tumors. The most frequently methylated genes in lung tumors were SCGB3A1 and DLC1 (both 50.0%. Methylation rates for ID4, DCL1, BNIP3, H2AFX, CACNA1G and TIMP3 were significantly different between squamous and adenocarcinomas. Methylation of RUNX3, SCGB3A1, SFRP4, and DLC1 was significantly associated with the extent of the disease when comparing localized versus metastatic tumors. Moreover, methylation of HTLF, SFRP5 and TIMP3 were significantly associated with overall survival. Conclusions MS-MLPA can be used for classification of certain types of lung tumors and clinical outcome prediction. This latter is clinically relevant by offering an adjunct strategy for the clinical management of lung cancer patients.

  18. Identical splicing of aberrant epidermal growth factor receptor transcripts from amplified rearranged genes in human glioblastomas.

    Sugawa, N; Ekstrand, A J; James, C D; Collins, V P

    1990-01-01

    The epidermal growth factor receptor gene has been found to be amplified and rearranged in human glioblastomas in vivo. Here we present the sequence across a splice junction of aberrant epidermal growth factor receptor transcripts derived from corresponding and uniquely rearranged genes that are coamplified and coexpressed with non-rearranged epidermal growth factor receptor genes in six primary human glioblastomas. Each of these six tumors contains aberrant transcripts derived from identical...

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

    Oliveira Jorge

    2007-07-01

    Full Text Available Abstract Background Aberrant 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. Methods A 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. Results Significant 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. Conclusion The 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.

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

    Aberrant 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. A 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. Significant 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. The 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

  1. Methylation of the chicken vitellogenin gene: influence of estradiol administration.

    Meijlink, F C; Philipsen, J N; Gruber, M; AB, G

    1983-01-01

    The degree of methylation of the chicken vitellogenin gene has been investigated. Upon induction by administration of estradiol to a rooster, methyl groups at specific sites near the 5'-end of the gene are eliminated. The process of demethylation is slower than the activation of the gene. Demethylation is therefore probably not a prerequisite to gene transcription. At least two other sites in the coding region of the gene are methylated in the liver of estrogenized roosters, but not in the li...

  2. Identification of 5 novel genes methylated in breast and other epithelial cancers

    Ward Robyn L

    2010-03-01

    Full Text Available Abstract Background There are several high throughput approaches to identify methylated genes in cancer. We utilized one such recently developed approach, MIRA (methylated-CpG island recovery assay combined with CpG island arrays to identify novel genes that are epigenetically inactivated in breast cancer. Results Using this approach we identified numerous CpG islands that demonstrated aberrant DNA methylation in breast cancer cell lines. Using a combination of COBRA and sequencing of bisulphite modified DNA, we confirmed 5 novel genes frequently methylated in breast tumours; EMILIN2, SALL1, DBC1, FBLN2 and CIDE-A. Methylation frequencies ranged from between 25% and 63% in primary breast tumours, whilst matched normal breast tissue DNA was either unmethylated or demonstrated a much lower frequency of methylation compared to malignant breast tissue DNA. Furthermore expression of the above 5 genes was shown to be restored following treatment with a demethylating agent in methylated breast cancer cell lines. We have expanded this analysis across three other common epithelial cancers (lung, colorectal, prostate. We demonstrate that the above genes show varying levels of methylation in these cancers. Lastly and most importantly methylation of EMILIN2 was associated with poorer clinical outcome in breast cancer and was strongly associated with estrogen receptor as well as progesterone receptor positive breast cancers. Conclusion The combination of the MIRA assay with CpG island arrays is a very useful technique for identifying epigenetically inactivated genes in cancer genomes and can provide molecular markers for early cancer diagnosis, prognosis and epigenetic therapy.

  3. Hierarchical clustering of breast cancer methylomes revealed differentially methylated and expressed breast cancer genes.

    I-Hsuan Lin

    Full Text Available Oncogenic transformation of normal cells often involves epigenetic alterations, including histone modification and DNA methylation. We conducted whole-genome bisulfite sequencing to determine the DNA methylomes of normal breast, fibroadenoma, invasive ductal carcinomas and MCF7. The emergence, disappearance, expansion and contraction of kilobase-sized hypomethylated regions (HMRs and the hypomethylation of the megabase-sized partially methylated domains (PMDs are the major forms of methylation changes observed in breast tumor samples. Hierarchical clustering of HMR revealed tumor-specific hypermethylated clusters and differential methylated enhancers specific to normal or breast cancer cell lines. Joint analysis of gene expression and DNA methylation data of normal breast and breast cancer cells identified differentially methylated and expressed genes associated with breast and/or ovarian cancers in cancer-specific HMR clusters. Furthermore, aberrant patterns of X-chromosome inactivation (XCI was found in breast cancer cell lines as well as breast tumor samples in the TCGA BRCA (breast invasive carcinoma dataset. They were characterized with differentially hypermethylated XIST promoter, reduced expression of XIST, and over-expression of hypomethylated X-linked genes. High expressions of these genes were significantly associated with lower survival rates in breast cancer patients. Comprehensive analysis of the normal and breast tumor methylomes suggests selective targeting of DNA methylation changes during breast cancer progression. The weak causal relationship between DNA methylation and gene expression observed in this study is evident of more complex role of DNA methylation in the regulation of gene expression in human epigenetics that deserves further investigation.

  4. Aberrant DNA methylation associated with MTHFR C677T genetic polymorphism in cutaneous squamous cell carcinoma in renal transplant patients.

    Laing, M E

    2010-08-01

    Changes in genomic DNA methylation associated with cancer include global DNA hypomethylation and gene-specific hyper- or hypomethylation. We have previously identified a genetic variant in the MTHFR gene involved in the methylation pathway which confers risk for the development of squamous cell carcinoma (SCC) in renal transplant patients. This genetic variant has also been discovered to confer SCC risk in nontransplant patients with low folate status.

  5. A Genome-Wide Methylation Approach Identifies a New Hypermethylated Gene Panel in Ulcerative Colitis

    Kang, Keunsoo; Bae, Jin-Han; Han, Kyudong; Kim, Eun Soo; Kim, Tae-Oh; Yi, Joo Mi

    2016-01-01

    The cause of inflammatory bowel disease (IBD) is still unknown, but there is growing evidence that environmental factors such as epigenetic changes can contribute to the disease etiology. The aim of this study was to identify newly hypermethylated genes in ulcerative colitis (UC) using a genome-wide DNA methylation approach. Using an Infinium HumanMethylation450 BeadChip array, we screened the DNA methylation changes in three normal colon controls and eight UC patients. Using these methylation profiles, 48 probes associated with CpG promoter methylation showed differential hypermethylation between UC patients and normal controls. Technical validations for methylation analyses in a larger series of UC patients (n = 79) were performed by methylation-specific PCR (MSP) and bisulfite sequencing analysis. We finally found that three genes (FAM217B, KIAA1614 and RIBC2) that were significantly elevating the promoter methylation levels in UC compared to normal controls. Interestingly, we confirmed that three genes were transcriptionally silenced in UC patient samples by qRT-PCR, suggesting that their silencing is correlated with the promoter hypermethylation. Pathway analyses were performed using GO and KEGG databases with differentially hypermethylated genes in UC. Our results highlight that aberrant hypermethylation was identified in UC patients which can be a potential biomarker for detecting UC. Moreover, pathway-enriched hypermethylated genes are possibly implicating important cellular function in the pathogenesis of UC. Overall, this study describes a newly hypermethylated gene panel in UC patients and provides new clinical information that can be used for the diagnosis and therapeutic treatment of IBD. PMID:27517910

  6. Detection of aberrant methylation in fecal DNA as a molecular screening tool for colorectal cancer and precancerous lesions

    Zhao-Hui Huang; Li-Hua Li; Fan Yang; Jin-Fu Wang

    2007-01-01

    AIM: To investigate the feasibility of detecting methylated fecal DNA as a screening tool for colorectal carcinoma (CRC) and precancerous lesions.METHODS: Methylated secreted frizzled-related protein gene 2 (SFRP2), hyperplastic polyposis protein gene (HPP1) and O6-methylguanine-DNA methyltransferase gene (MGMT) in stools from 52 patients with CRC, 35 patients with benign colorectal diseases and 24 normal individuals were analyzed using methylation-specific PCR.RESULTS: Methylated SFRP2, HPP1 and MGMT were detected in 94.2%, 71.2%, 48.1% of CRC patients and 52.4%, 57.1%, 28.6% of adenoma patients, respectively. The overall prevalence of fecal DNA with at least one methylated gene was 96.2% and 81.8% in patients with CRC and precancerous lesions, respectively. In contrast, only one of the 24 normal individuals revealed methylated DNA. These results indicated a 93.7% sensitivity and a 77.1% specificity of the assay for detecting CRC and precancerous lesions.CONCLUSION: Methylation testing of fecal DNA using a panel of epigenetic markers may be a simple and promising non-invasive screening method for CRC and precancerous lesions.

  7. Methylation profiling of twenty promoter-CpG islands of genes which may contribute to hepatocellular carcinogenesis

    Hepatocellular carcinoma (HCC) presents one of the major health threats in China today. A better understanding of the molecular genetics underlying malignant transformation of hepatocytes is critical to success in the battle against this disease. The methylation state of C5 of the cytosine in the CpG di-nucleotide that is enriched within or near the promoter region of over 50 % of the polymerase II genes has a drastic effect on transcription of these genes. Changes in the methylation profile of the promoters represent an alternative to genetic lesions as causative factors for the tumor-specific aberrant expression of the genes. We have used the methylation specific PCR method in conjunction with DNA sequencing to assess the methylation state of the promoter CpG islands of twenty genes. Aberrant expression of these genes have been attributed to the abnormal methylation profile of the corresponding promoter CpG islands in human tumors. While the following sixteen genes remained the unmethylated in all tumor and normal tissues: CDH1, APAF1, hMLH1, BRCA1, hTERC, VHL, RARβ, TIMP3, DAPK1, SURVIVIN, p14ARF, RB1, p15INK4b, APC, RASSF1c and PTEN, varying degrees of tumor specific hypermethylation were associated with the p16INK4a, RASSF1a, CASP8 and CDH13 genes. For instance, the p16INK4a was highly methylated in HCC (17/29, 58.6%) and less significantly methylated in non-cancerous tissue (4/29. 13.79%). The RASSF1a was fully methylated in all tumor tissues (29/29, 100%), and less frequently methylated in corresponding non-cancerous tissue (24/29, 82.75%). Furthermore, co-existence of methylated with unmethylated DNA in some cases suggested that both genetic and epigenetic (CpG methylation) mechanisms may act in concert to inactivate the p16INK4a and RASSF1a in HCC. Finally, we found a significant association of cirrhosis with hypermethylation of the p16INK4a and hypomethylation of the CDH13 genes. For the first time, the survey was carried out on such an extent that it

  8. Aberrantly Methylated MGMT, hMLH1 and hMSH2 in Tumor and Serum DNA of Gliomas Patients

    Changqing Zheng; Shouping Ji; Feng Gong; Anming Li; Junli Tai; Subuo Li; Yingli Wang; Hongyu Chang; Hongwei Gao; Yangpei Zhang

    2009-01-01

    OBJECTIVE This study is to investigate the prevalence of promoter CpG island methylation of O6-methylguananine-DNA methyltransferase (MGMT), mismatch repair genes (hMLH1 and hMSH2) in both tumor and serum samples of gliomas.METHODS Methylation-specific PCR (MSP) was employed to detect promoter CpG island methylation of the MGMT, hMLH1 and hMSH2 genes in 39 samples taken from surgery and 32 samples of pretreatment serum all from the patients with gliomas.RESULTS Promoter CpG island methylation of MGMT, hMLH1 and hMSH2 was detected and the results were 46.2%, 10.3% and 20.5%, respectively in tumor DNA of the cases with gliomas,and 40.6%, 9.4% and 18.8%, respectively in serum DNA of the cases. The methylation pattern in primary tumor and serum was found to be concordant in matched tissue and serum samples of 21 patients. In the cases with positive result of methylation for MGMT, hMLH1 and hMSH2 in tumor tissues, the results of detection for those in the paired serum sample were 77.8% (7/9),66.7% (2/3) and 75.0 % (3/4), respectively. False positive results were not obtained in any of the patients who did not exhibit methylation. No association was found between the promoter methylation of MGMT, hMLH1, and hMSH2 genes in primary gliomas and gender, age, localization, grade of malignant or tumor stage.CONCLUSION Promoter CpG island methylation is a frequent event in gliomagenesis. Methylation analysis appears to be a promising predictive factor of the prognosis for the glioma patients treated with alkylating drugs and a noninvasive tumor marker in serum DNA.

  9. Promoter methylation and expression levels of selected hematopoietic genes in pediatric B-cell acute lymphoblastic leukemia

    Musialik, Ewa; Bujko, Mateusz; Kober, Paulina; Agnieszka WYPYCH; Gawle-Krawczyk, Karolina; Matysiak, Michal; Siedlecki, Janusz Aleksander

    2015-01-01

    Background Precursor B-cell acute lymphoblastic leukemia (B-cell ALL) is the most common neoplasm in children and is characterized by genetic and epigenetic aberrations in hematopoietic transcription factor (TF) genes. This study evaluated promoter DNA methylation and aberrant expression levels of early- and late-acting hematopoietic TF genes homeobox A4 and A5 (HOXA4 and HOXA5), Meis homeobox 1 (MEIS1), T-cell acute lymphocytic leukemia 1 (TAL1), and interferon regulatory factors 4 and 8 (IR...

  10. Divergence of Gene Body DNA Methylation and Evolution of Plant Duplicate Genes

    Wang, Jun; Marowsky, Nicholas C.; Fan, Chuanzhu

    2014-01-01

    It has been shown that gene body DNA methylation is associated with gene expression. However, whether and how deviation of gene body DNA methylation between duplicate genes can influence their divergence remains largely unexplored. Here, we aim to elucidate the potential role of gene body DNA methylation in the fate of duplicate genes. We identified paralogous gene pairs from Arabidopsis and rice (Oryza sativa ssp. japonica) genomes and reprocessed their single-base resolution methylome data....

  11. Investigation of DNA damage response and apoptotic gene methylation pattern in sporadic breast tumors using high throughput quantitative DNA methylation analysis technology

    Prakash Neeraj

    2010-11-01

    Full Text Available Abstract Background- Sporadic breast cancer like many other cancers is proposed to be a manifestation of abnormal genetic and epigenetic changes. For the past decade our laboratory has identified genes involved in DNA damage response (DDR, apoptosis and immunesurvelliance pathways to influence sporadic breast cancer risk in north Indian population. Further to enhance our knowledge at the epigenetic level, we performed DNA methylation study involving 17 gene promoter regions belonging to DNA damage response (DDR and death receptor apoptotic pathway in 162 paired normal and cancerous breast tissues from 81 sporadic breast cancer patients, using a high throughput quantitative DNA methylation analysis technology. Results- The study identified five genes with statistically significant difference between normal and tumor tissues. Hypermethylation of DR5 (P = 0.001, DCR1 (P = 0.00001, DCR2 (P = 0.0000000005 and BRCA2 (P = 0.007 and hypomethylation of DR4 (P = 0.011 in sporadic breast tumor tissues suggested a weak/aberrant activation of the DDR/apoptotic pathway in breast tumorigenesis. Negative correlation was observed between methylation status and transcript expression levels for TRAIL, DR4, CASP8, ATM, CHEK2, BRCA1 and BRCA2 CpG sites. Categorization of the gene methylation with respect to the clinicopathological parameters showed an increase in aberrant methylation pattern in advanced tumors. These uncharacteristic methylation patterns corresponded with decreased death receptor apoptosis (P = 0.047 and DNA damage repair potential (P = 0.004 in advanced tumors. The observation of BRCA2 -26 G/A 5'UTR polymorphism concomitant with the presence of methylation in the promoter region was novel and emerged as a strong candidate for susceptibility to sporadic breast tumors. Conclusion- Our study indicates that methylation of DDR-apoptotic gene promoters in sporadic breast cancer is not a random phenomenon. Progressive epigenetic alterations in advancing

  12. Whole blood DNA aberrant methylation in pancreatic adenocarcinoma shows association with the course of the disease: a pilot study.

    Albertas Dauksa

    Full Text Available Pancreatic tumors are usually diagnosed at an advanced stage in the progression of the disease, thus reducing the survival chances of the patients. Non-invasive early detection would greatly enhance therapy and survival rates. Toward this aim, we investigated in a pilot study the power of methylation changes in whole blood as predictive markers for the detection of pancreatic tumors. We investigated methylation levels at selected CpG sites in the CpG rich regions at the promoter regions of p16, RARbeta, TNFRSF10C, APC, ACIN1, DAPK1, 3OST2, BCL2 and CD44 in the blood of 30 pancreatic tumor patients and in the blood of 49 matching controls. In addition, we studied LINE-1 and Alu repeats using degenerate amplification approach as a surrogate marker for genome-wide methylation. The site-specific methylation measurements at selected CpG sites were done by the SIRPH method. Our results show that in the patient's blood, tumor suppressor genes were slightly but significantly higher methylated at several CpG sites, while repeats were slightly less methylated compared to control blood. This was found to be significantly associated with higher risk for pancreatic ductal adenocarcinoma. Additionally, high methylation levels at TNFRSCF10C were associated with positive perineural spread of tumor cells, while higher methylation levels of TNFRSF10C and ACIN1 were significantly associated with shorter survival. This pilot study shows that methylation changes in blood could provide a promising method for early detection of pancreatic tumors. However, larger studies must be carried out to explore the clinical usefulness of a whole blood methylation based test for non-invasive early detection of pancreatic tumors.

  13. Gain of DNA methylation is enhanced in the absence of CTCF at the human retinoblastoma gene promoter

    Recillas-Targa Félix

    2011-06-01

    Full Text Available Abstract Background Long-term gene silencing throughout cell division is generally achieved by DNA methylation and other epigenetic processes. Aberrant DNA methylation is now widely recognized to be associated with cancer and other human diseases. Here we addressed the contribution of the multifunctional nuclear factor CTCF to the epigenetic regulation of the human retinoblastoma (Rb gene promoter in different tumoral cell lines. Methods To assess the DNA methylation status of the Rb promoter, genomic DNA from stably transfected human erythroleukemic K562 cells expressing a GFP reporter transgene was transformed with sodium bisulfite, and then PCR-amplified with modified primers and sequenced. Single- and multi-copy integrants with the CTCF binding site mutated were isolated and characterized by Southern blotting. Silenced transgenes were reactivated using 5-aza-2'-deoxycytidine and Trichostatin-A, and their expression was monitored by fluorescent cytometry. Rb gene expression and protein abundance were assessed by RT-PCR and Western blotting in three different glioma cell lines, and DNA methylation of the promoter region was determined by sodium bisulfite sequencing, together with CTCF dissociation and methyl-CpG-binding protein incorporation by chromatin immunoprecipitation assays. Results We found that the inability of CTCF to bind to the Rb promoter causes a dramatic loss of gene expression and a progressive gain of DNA methylation. Conclusions This study indicates that CTCF plays an important role in maintaining the Rb promoter in an optimal chromatin configuration. The absence of CTCF induces a rapid epigenetic silencing through a progressive gain of DNA methylation. Consequently, CTCF can now be seen as one of the epigenetic components that allows the proper configuration of tumor suppressor gene promoters. Its aberrant dissociation can then predispose key genes in cancer cells to acquire DNA methylation and epigenetic silencing.

  14. Gain of DNA methylation is enhanced in the absence of CTCF at the human retinoblastoma gene promoter

    Long-term gene silencing throughout cell division is generally achieved by DNA methylation and other epigenetic processes. Aberrant DNA methylation is now widely recognized to be associated with cancer and other human diseases. Here we addressed the contribution of the multifunctional nuclear factor CTCF to the epigenetic regulation of the human retinoblastoma (Rb) gene promoter in different tumoral cell lines. To assess the DNA methylation status of the Rb promoter, genomic DNA from stably transfected human erythroleukemic K562 cells expressing a GFP reporter transgene was transformed with sodium bisulfite, and then PCR-amplified with modified primers and sequenced. Single- and multi-copy integrants with the CTCF binding site mutated were isolated and characterized by Southern blotting. Silenced transgenes were reactivated using 5-aza-2'-deoxycytidine and Trichostatin-A, and their expression was monitored by fluorescent cytometry. Rb gene expression and protein abundance were assessed by RT-PCR and Western blotting in three different glioma cell lines, and DNA methylation of the promoter region was determined by sodium bisulfite sequencing, together with CTCF dissociation and methyl-CpG-binding protein incorporation by chromatin immunoprecipitation assays. We found that the inability of CTCF to bind to the Rb promoter causes a dramatic loss of gene expression and a progressive gain of DNA methylation. This study indicates that CTCF plays an important role in maintaining the Rb promoter in an optimal chromatin configuration. The absence of CTCF induces a rapid epigenetic silencing through a progressive gain of DNA methylation. Consequently, CTCF can now be seen as one of the epigenetic components that allows the proper configuration of tumor suppressor gene promoters. Its aberrant dissociation can then predispose key genes in cancer cells to acquire DNA methylation and epigenetic silencing

  15. An integrative multi-dimensional genetic and epigenetic strategy to identify aberrant genes and pathways in cancer

    Lockwood William W

    2010-05-01

    Full Text Available Abstract Background Genomics has substantially changed our approach to cancer research. Gene expression profiling, for example, has been utilized to delineate subtypes of cancer, and facilitated derivation of predictive and prognostic signatures. The emergence of technologies for the high resolution and genome-wide description of genetic and epigenetic features has enabled the identification of a multitude of causal DNA events in tumors. This has afforded the potential for large scale integration of genome and transcriptome data generated from a variety of technology platforms to acquire a better understanding of cancer. Results Here we show how multi-dimensional genomics data analysis would enable the deciphering of mechanisms that disrupt regulatory/signaling cascades and downstream effects. Since not all gene expression changes observed in a tumor are causal to cancer development, we demonstrate an approach based on multiple concerted disruption (MCD analysis of genes that facilitates the rational deduction of aberrant genes and pathways, which otherwise would be overlooked in single genomic dimension investigations. Conclusions Notably, this is the first comprehensive study of breast cancer cells by parallel integrative genome wide analyses of DNA copy number, LOH, and DNA methylation status to interpret changes in gene expression pattern. Our findings demonstrate the power of a multi-dimensional approach to elucidate events which would escape conventional single dimensional analysis and as such, reduce the cohort sample size for cancer gene discovery.

  16. METHYLATION PATTERN OF LRP15 GENE IN LEUKEMIA

    2007-01-01

    Objective To investigate the methylation status of LRP15 gene in acute leukemia (AL) patients and its role in the tumorigenesis.Methods The methylation of LRP15 promoter and first exon of bone marrow mononuclear cells in 73 patients with AL, 10 with chronic leukemia (CL), 9 with hematological benign diseases, and 20 healthy transplantation donors was analyzed by using methylation specific polymerase chain reaction. The methylation of LRP15 gene promoter and first exon in COS7, K562, and HL60 cell lines was also assayed.Results No LRP15 gene promoter methylation was detected in COS7 cell line. LRP15 gene promoter was methylated in K562 and HL60 cell lines. No deletion of LRP15 gene was detected in all samples. In nearly all French-American-British leukemia subtypes, we found that frequency of LRP15 methylation in adult patients with AL was 71.23%( 52/73 ). There was no detectable methylation in any of the 20 healthy donors and 8 chronic myeloid leukemia patients.The difference in frequency of LRP15 methylation between AL patients and healthy donors or CL patients ( 10. 00%,1/10) was significant (P < 0. 01 ). Hypermethylation of LRP15 gene was found in 57. 14% (16/28) of newly diagnosed AL patients, 83.33% of relapsed AL patients respectively, which was significantly different ( P < 0. 05). We also demonstrated LRP15 methylation in 55.56% (5/9) adults with benign hematological diseases.Conclusions LRP15 methylation changes are common abnormalities in leukemia. LRP15 is postulated to be a tumor suppressor gene.

  17. Importance of Tumour Suppressor Gene Methylation in Sinonasal Carcinomas.

    Chmelařová, M; Sirák, I; Mžik, M; Sieglová, K; Vošmiková, H; Dundr, P; Němejcová, K; Michálek, J; Vošmik, M; Palička, V; Laco, J

    2016-01-01

    Epigenetic changes are considered to be a frequent event during tumour development. Hypermethylation of promoter CpG islands represents an alternative mechanism for inactivation of tumour suppressor genes, DNA repair genes, cell cycle regulators and transcription factors. The aim of this study was to investigate promoter methylation of specific genes in samples of sinonasal carcinoma by comparison with normal sinonasal tissue. To search for epigenetic events we used methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) to compare the methylation status of 64 tissue samples of sinonasal carcinomas with 19 control samples. We also compared the human papilloma virus (HPV) status with DNA methylation. Using a 20% cut-off for methylation, we observed significantly higher methylation in RASSF1, CDH13, ESR1 and TP73 genes in the sinonasal cancer group compared with the control group. HPV positivity was found in 15/64 (23.4 %) of all samples in the carcinoma group and in no sample in the control group. No correlation was found between DNA methylation and HPV status. In conclusion, our study showed that there are significant differences in promoter methylation in the RASSF1, ESR 1, TP73 and CDH13 genes between sinonasal carcinoma and normal sinonasal tissue, suggesting the importance of epigenetic changes in these genes in carcinogenesis of the sinonasal area. These findings could be used as prognostic factors and may have implications for future individualised therapies based on epigenetic changes. PMID:27516190

  18. Gene expression and epigenetic discovery screen reveal methylation of SFRP2 in prostate cancer.

    Perry, Antoinette S

    2013-04-15

    Aberrant activation of Wnts is common in human cancers, including prostate. Hypermethylation associated transcriptional silencing of Wnt antagonist genes SFRPs (Secreted Frizzled-Related Proteins) is a frequent oncogenic event. The significance of this is not known in prostate cancer. The objectives of our study were to (i) profile Wnt signaling related gene expression and (ii) investigate methylation of Wnt antagonist genes in prostate cancer. Using TaqMan Low Density Arrays, we identified 15 Wnt signaling related genes with significantly altered expression in prostate cancer; the majority of which were upregulated in tumors. Notably, histologically benign tissue from men with prostate cancer appeared more similar to tumor (r = 0.76) than to benign prostatic hyperplasia (BPH; r = 0.57, p < 0.001). Overall, the expression profile was highly similar between tumors of high (≥ 7) and low (≤ 6) Gleason scores. Pharmacological demethylation of PC-3 cells with 5-Aza-CdR reactivated 39 genes (≥ 2-fold); 40% of which inhibit Wnt signaling. Methylation frequencies in prostate cancer were 10% (2\\/20) (SFRP1), 64.86% (48\\/74) (SFRP2), 0% (0\\/20) (SFRP4) and 60% (12\\/20) (SFRP5). SFRP2 methylation was detected at significantly lower frequencies in high-grade prostatic intraepithelial neoplasia (HGPIN; 30%, (6\\/20), p = 0.0096), tumor adjacent benign areas (8.82%, (7\\/69), p < 0.0001) and BPH (11.43% (4\\/35), p < 0.0001). The quantitative level of SFRP2 methylation (normalized index of methylation) was also significantly higher in tumors (116) than in the other samples (HGPIN = 7.45, HB = 0.47, and BPH = 0.12). We show that SFRP2 hypermethylation is a common event in prostate cancer. SFRP2 methylation in combination with other epigenetic markers may be a useful biomarker of prostate cancer.

  19. Integrated analysis of gene expression and genomic aberration data in osteosarcoma (OS).

    Xiong, Y; Wu, S; Du, Q; Wang, A; Wang, Z

    2015-11-01

    Cytogenetic analyses have revealed that complex karyotypes with numerous and highly variable genomic aberrations including single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs), are observed in most of the conventional osteosarcomas (OSs). Several genome-wide studies have reported that the dysregulated expression of many genes is correlated with genomic aberrations in OS. We first compared OS gene expression in Gene Expression Omnibus (GEO) data sets and genomic aberrations in International Cancer Genome Consortium (ICGC) database to identify differentially expressed genes (DEGs) associated with SNPs or CNVs in OS. Then the function annotation of SNP- or CNV-associated DEGs was performed in terms of gene ontology analysis, pathway analysis and protein-protein interactions (PPIs). Finally, the expression of genes correlated with both SNPs and CNVs were confirmed by quantitative reverse-transcription PCR. Eight publicly available GEO data sets were obtained, and a set of 979 DEGs were identified (472 upregulated and 507 downregulated DEGs). Moreover, we obtained 1039 SNPs mapped in 938 genes, and 583 CNV sites mapped in 2915 genes. Comparing genomic aberrations and DGEs, we found 41 SNP-associated DEGs and 124 CNV-associated DEGs, in which 7 DGEs were associated with both SNPs and CNVs, including WWP1, EXT1, LDHB, C8orf59, PLEKHA5, CCT3 and VWF. The result of function annotation showed that ossification, bone development and skeletal system development were the significantly enriched terms of biological processes for DEGs. PPI network analysis showed that CCT3, COPS3 and WWP1 were the significant hub proteins. We conclude that these genes, including CCT3, COPS3 and WWP1 are candidate driver genes of importance in OS tumorigenesis. PMID:26427513

  20. Aberrant methylation of NPY, PENK, and WIF1 as a promising marker for blood-based diagnosis of colorectal cancer

    Roperch, J.-P.

    2013-12-01

    Background: DNA methylation is a well-known epigenetic mechanism involved in epigenetic gene regulation. Several genes were reported hypermethylated in CRC, althought no gene marker was proven to be individually of sufficient sensitivity or specificity in routine clinical practice. Here, we identified novel epigenetic markers and assessed their combined use for diagnostic accuracy.Methods: We used methylation arrays on samples from several effluents to characterize methylation profiles in CRC samples and controls, as established by colonoscopy and pathology findings, and selected two differentially methylated candidate epigenetic genes (NPY, PENK). To this gene panel we added WIF, on the basis of being reported in literature as silenced by promoter hypermethylation in several cancers, including CRC. We measured their methylation degrees by quantitative multiplex-methylation specific PCR (QM-MSP) on 15 paired carcinomas and adjacent non-cancerous colorectal tissues and we subsequently performed a clinical validation on two different series of 266 serums, subdivided in 32 CRC, 26 polyps, 47 other cancers and 161 with normal colonoscopy. We assessed the results by receiver operating characteristic curve (ROC), using cumulative methylation index (CMI) as variable threshold.Results: We obtained CRC detection on tissues with both sensitivity and specificity of 100%. On serum CRC samples, we obtained sensitivity/specificity values of, e.g., 87%/80%, 78%/90% and 59%/95%, and negative predictive value/positive predictive value figures of 97%/47%, 95%/61% and 92%/70%. On serum samples from other cancers we obtained sensitivity/specificity of, e.g, 89%/25%, 43%/80% and 28%/91%.Conclusions: We showed the potential of NPY, PENK, and WIF1 as combined epigenetic markers for CRC diagnosis, both in tissue and serum and tested their use as serum biomarkers in other cancers. We optimized a QM-MSP for simultaneously quantifying their methylation levels. Our assay can be an effective

  1. Effect of phenylhexyl isothiocyanate on aberrant histone H3 methylation in primary human acute leukemia

    Zou Yong

    2012-07-01

    Full Text Available Abstract Background We have previously studied the histone acetylation in primary human leukemia cells. However, histone H3 methylation in these cells has not been characterized. Methods This study examined the methylation status at histone H3 lysine 4 (H3K4 and histone H3 lysine 9 (H3K9 in primary acute leukemia cells obtained from patients and compared with those in the non-leukemia and healthy cells. We further characterized the effect of phenylhexyl isothiocyanate (PHI, Trichostatin A (TSA, and 5-aza-2’-deoxycytidine (5-Aza on the cells. Results We found that methylation of histone H3K4 was virtually undetectable, while methylation at H3K9 was significantly higher in primary human leukemia cells. The histone H3K9 hypermethylation and histone H3K4 hypomethylation were observed in both myeloid and lymphoid leukemia cells. PHI was found to be able to normalize the methylation level in the primary leukemia cells. We further showed that PHI was able to enhance the methyltransferase activity of H3K4 and decrease the activity of H3K9 methyltransferase. 5-Aza had similar effect on H3K4, but minimal effect on H3K9, whereas TSA had no effect on H3K4 and H3K9 methyltransferases. Conclusions This study revealed opposite methylation level of H3K4 and H3K9 in primary human leukemia cells and demonstrated for the first time that PHI has different effects on the methyltransferases for H3K4 and H3K9.

  2. Global assessment of promoter methylation in a mouse model of cancer identifies ID4 as a putative tumor-suppressor gene in human leukemia

    LiYu; ChunhuiLiu; JeffVandeusen; BrianBecknell; ZunyanDai; Yue-ZhongWu; AparnaRaval; Te-HuiLiu; WeiDing; CharleneMao; ShujunLiu; LauraTSmith; StephenLee; LauraRassenti; GuidoMarcucci; JohnByrd; MichaelACaligiuri; ChristophPlass

    2005-01-01

    DNA methylation is associated with malignant transformation, but limitations imposed by genetic variability, tumor heterogeneity, availability of paired normal tissues and methodologies for global assessment of DNA methylation have limited progress in understanding the extent of epigenetic events in the initiation and progression of human cancer and in identifying genes that undergo methylation during cancer. We developed a mouse model of T/natural killer acute lymphoblastic leukemia that is always preceded by polyclonal lymphocyte expansion to determine how aberrant promoter DNA methylation and consequent gene silencing might be contributing to leukemic transformation. We used restriction landmark genomic scanning with this mouse model of preleukemia reproducibly progressing to leukemia to show that specific genomic methylation is associated with only the leukemic phase and is not random. We also identified Idb4 as a putative tumor-suppressor gene that is methylated in most mouse and human leukemias but in only a minority of other human cancers.

  3. Relationship between promoter methylation & tissue expression of MGMT gene in ovarian cancer

    V Shilpa

    2014-01-01

    Full Text Available Background & objectives: Epigenetic alterations, in addition to multiple gene abnormalities, are involved in the genesis and progression of human cancers. Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumour suppressor genes. O 6 -methyguanine-DNA methyltransferase (MGMT is a DNA repair gene that removes mutagenic and cytotoxic adducts from the O 6 -position of guanine induced by alkylating agents. MGMT promoter hypermethylation and reduced expression has been found in some primary human carcinomas. We studied DNA methylation of CpG islands of the MGMT gene and its relation with MGMT protein expression in human epithelial ovarian carcinoma. Methods: A total of 88 epithelial ovarian cancer (EOC tissue samples, 14 low malignant potential (LMP tumours and 20 benign ovarian tissue samples were analysed for MGMT promoter methylation by nested methylation-specific polymerase chain reaction (MSP after bisulphite modification of DNA. A subset of 64 EOC samples, 10 LMP and benign tumours and five normal ovarian tissue samples were analysed for protein expression by immunohistochemistry. Results: The methylation frequencies of the MGMT gene promoter were found to be 29.5, 28.6 and 20 per cent for EOC samples, LMP tumours and benign cases, respectively. Positive protein expression was observed in 93.8 per cent of EOC and 100 per cent in LMP, benign tumours and normal ovarian tissue samples. Promoter hypermethylation with loss of protein expression was seen only in one case of EOC. Interpretation & conclusions: Our results suggest that MGMT promoter hypermethylation does not always reflect gene expression.

  4. Relationship between promoter methylation & tissue expression of MGMT gene in ovarian cancer

    Shilpa, V.; Bhagat, Rahul; Premalata, C.S.; Pallavi, V.R.; Ramesh, G.; Krishnamoorthy, Lakshmi

    2014-01-01

    Background & objectives: Epigenetic alterations, in addition to multiple gene abnormalities, are involved in the genesis and progression of human cancers. Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumour suppressor genes. O6-methyguanine-DNA methyltransferase (MGMT) is a DNA repair gene that removes mutagenic and cytotoxic adducts from the O6-position of guanine induced by alkylating agents. MGMT promoter hypermethylation and reduced expression has been found in some primary human carcinomas. We studied DNA methylation of CpG islands of the MGMT gene and its relation with MGMT protein expression in human epithelial ovarian carcinoma. Methods: A total of 88 epithelial ovarian cancer (EOC) tissue samples, 14 low malignant potential (LMP) tumours and 20 benign ovarian tissue samples were analysed for MGMT promoter methylation by nested methylation-specific polymerase chain reaction (MSP) after bisulphite modification of DNA. A subset of 64 EOC samples, 10 LMP and benign tumours and five normal ovarian tissue samples were analysed for protein expression by immunohistochemistry. Results: The methylation frequencies of the MGMT gene promoter were found to be 29.5, 28.6 and 20 per cent for EOC samples, LMP tumours and benign cases, respectively. Positive protein expression was observed in 93.8 per cent of EOC and 100 per cent in LMP, benign tumours and normal ovarian tissue samples. Promoter hypermethylation with loss of protein expression was seen only in one case of EOC. Interpretation & conclusions: Our results suggest that MGMT promoter hypermethylation does not always reflect gene expression. PMID:25579142

  5. Aberrant chromatin at genes encoding stem cell regulators in human mixed-lineage leukemia

    Guenther, Matthew G.; Lawton, Lee N.; Rozovskaia, Tatiana; Frampton, Garrett M.; Levine, Stuart S.; Thomas L Volkert; Croce, Carlo M.; Nakamura, Tatsuya; Canaani, Eli; Young, Richard A.

    2008-01-01

    Mixed-lineage leukemia (MLL) fusion proteins are potent inducers of leukemia, but how these proteins generate aberrant gene expression programs is poorly understood. Here we show that the MLL-AF4 fusion protein occupies developmental regulatory genes important for hematopoietic stem cell identity and self-renewal in human leukemia cells. These MLL-AF4-bound regions have grossly altered chromatin structure, with histone modifications catalyzed by trithorax group proteins and DOT1 extending acr...

  6. Agglomerates of aberrant DNA methylation are associated with toxicant-induced malignant transformation

    Severson, P.L.; Tokar, E.J.; Vrba, Lukáš; Waalkes, M.P.; Futscher, B. W.

    2012-01-01

    Roč. 7, č. 11 (2012), s. 1238-1248. ISSN 1559-2294 Institutional research plan: CEZ:AV0Z50510513 Keywords : agglomerative DNA methylation * H3K27me3 * H3K9me3 * epigenetic s Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.920, year: 2012

  7. Gene Body Methylation can alter Gene Expression and is a Therapeutic Target in Cancer

    Yang, Xiaojing; Han, Han; De Carvalho, Daniel D.; Lay, Fides D.; Jones, Peter A.; Liang, Gangning

    2014-01-01

    SUMMARY DNA methylation in promoters is well known to silence genes and is the presumed therapeutic target of methylation inhibitors. Gene body methylation is positively correlated with expression yet its function is unknown. We show that 5-aza-2'-deoxycytidine treatment not only reactivates genes but decreases the over-expression of genes, many of which are involved in metabolic processes regulated by c-MYC. Down-regulation is caused by DNA demethylation of the gene bodies and restoration of high levels of expression requires remethylation by DNMT3B. Gene body methylation may therefore be an unexpected therapeutic target for DNA methylation inhibitors, resulting in the normalization of gene over-expression induced during carcinogenesis. Our results provide direct evidence for a causal relationship between gene body methylation and transcription. PMID:25263941

  8. Allium cepa anaphase-telophase root tip chromosome aberration assay on N-methyl-N-nitrosourea, maleic hydrazide, sodium azide, and ethyl methanesulfonate.

    Rank, J; Nielsen, M H

    1997-04-24

    The Allium anaphase-telophase assay was used to show genotoxicity of N-methyl-N-nitrosourea (MNU), maleic hydrazide (MH), sodium azide (NaN3) and ethyl methanesulfonate (EMS). All agents induced chromosome aberrations at statistically significant levels. The rank of the lowest doses with positive effect was as follows: NaN3 0.3 mg/l Allium test for NaN3 and EMS were in a lower range than that found for the other plant assays. EMS and MMS (methyl methanesulfonate), two chemicals used as positive controls in mutagenicity testing, were compared in the Allium test, and MMS was found to be about ten times more potent in inducing chromosome aberrations than EMS. Recording of micronuclei in interphase cells showed that this endpoint does not give more information of clastogenicity than recording of chromosome aberrations in anaphase-telophase cells. PMID:9150760

  9. Gene promoter methylation patterns throughout the process of cervical carcinogenesis

    Yang, Nan; Nijhuis, Esther R.; Volders, Haukeline H.; Eijsink, Jasper J. H.; Lendvai, Agnes; Zhang, Bo; Hollema, Harry; Schuuring, Ed; Wisman, G. Bea A.; van der Zee, Ate G. J.

    2010-01-01

    Objectives: To determine methylation status of nine genes, previously described to be frequently methylated in cervical cancer, in squamous intraepithelial lesions (SIL). Methods: QMSP was performed in normal cervix, low-grade ( L) SIL, high-grade (H) SIL, adenocarcinomas and squamous cell cervical

  10. INACTIVATION OF THE CDKN2/pl6 GENE INDUCED BY METHYLATION AT 5'-CpG ISLAND AND ITS RELATION TO LUNG CANCER

    2001-01-01

    Objectives: To investigate the methylation status of the CDKN2/pl6 gene 5'-CpG island, and study the relationship between the CDKN2/pl6 gene inacti-vation by methylation and lung cancer. Methods: Genomic DNA extracted from the specimens of lung cancer and normal lung tissue was digested with methylation-sensitive endonucleases, and Southern blotting was used to analyze the methylation status of the CDKN2/pl6 gene in 89 cases of lung cancer and 10 cases of normal lung tissue. Results: In 89 cases of lung cancer studied, the CDKN2/pl6 gene was shown to be methylated in 21 cases with the total methylation rate of 23.6% (21/89), in which there were 15 cases (16.9%) methylated at SmaI sites, 12 cases (13.5%) at SacII sites and 6 cases at both SmaI and SacII sites. The methylation of the CDKN2/pl6 gene occurred in 17 among 42 of pl6 protein negative cases of lung cancer with a rate of 40.5% (17/42), and in 3 among 47 of pl6 protein positive cases with a Conclusion: The aberrant methylation of the CDKN2/pl6 gene 5'-CpG island is probably an important mechanism of the gene inactivation, it may be involved in the genesis and progress of lung cancer.

  11. On the presence and role of human gene-body DNA methylation

    Jjingo, Daudi; Conley, Andrew B.; Yi, Soojin V; Lunyak, Victoria V.; Jordan, I. King

    2012-01-01

    DNA methylation of promoter sequences is a repressive epigenetic mark that down-regulates gene expression. However, DNA methylation is more prevalent within gene-bodies than seen for promoters, and gene-body methylation has been observed to be positively correlated with gene expression levels. This paradox remains unexplained, and accordingly the role of DNA methylation in gene-bodies is poorly understood. We addressed the presence and role of human gene-body DNA methylation using a meta-anal...

  12. Divergence of gene body DNA methylation and evolution of plant duplicate genes.

    Jun Wang

    Full Text Available It has been shown that gene body DNA methylation is associated with gene expression. However, whether and how deviation of gene body DNA methylation between duplicate genes can influence their divergence remains largely unexplored. Here, we aim to elucidate the potential role of gene body DNA methylation in the fate of duplicate genes. We identified paralogous gene pairs from Arabidopsis and rice (Oryza sativa ssp. japonica genomes and reprocessed their single-base resolution methylome data. We show that methylation in paralogous genes nonlinearly correlates with several gene properties including exon number/gene length, expression level and mutation rate. Further, we demonstrated that divergence of methylation level and pattern in paralogs indeed positively correlate with their sequence and expression divergences. This result held even after controlling for other confounding factors known to influence the divergence of paralogs. We observed that methylation level divergence might be more relevant to the expression divergence of paralogs than methylation pattern divergence. Finally, we explored the mechanisms that might give rise to the divergence of gene body methylation in paralogs. We found that exonic methylation divergence more closely correlates with expression divergence than intronic methylation divergence. We show that genomic environments (e.g., flanked by transposable elements and repetitive sequences of paralogs generated by various duplication mechanisms are associated with the methylation divergence of paralogs. Overall, our results suggest that the changes in gene body DNA methylation could provide another avenue for duplicate genes to develop differential expression patterns and undergo different evolutionary fates in plant genomes.

  13. Glioblastoma and the significance of MGMT gene methylation

    Payam Izadpanahi

    2014-08-01

    Full Text Available In this research Glioblastoma has been studied as one of the most common brain tumors and a short review of the available therapeutic methods have presented including surgery, radiotherapy, chemotherapy and particularly adjuvant chemotherapy with temozolomide, as the most effective developed treatment. Moreover, MGMT gene promoter methylation has been introduced as an important predictive factor of treatment response to temozolamide. The different mechanisms of methylation and the availableliterature on its association with patient survival and disease recurrence have been summarized. Taken together, Glioblastoma is a tumor in which the MGMT gene expression can potentially deliver the highest amount of data in comparison to other tumors; as almost every related study has emphasized on the direct association between MGMT methylation and patient survival. Regarding this debate, the pseudoprogression pattern in Glioblastoma patients and the laboratory methods studying MGMT gene methylation have been examined. At the end of this review, the obstacles to its development have been briefly mentioned.

  14. Heritable Transmission of Diabetic Metabolic Memory in Zebrafish Correlates With DNA Hypomethylation and Aberrant Gene Expression

    Olsen, Ansgar S.; Sarras, Michael P.; LEONTOVICH, ALEXEY; Intine, Robert V.

    2012-01-01

    Metabolic memory (MM) is the phenomenon whereby diabetes complications persist and progress after glycemic recovery is achieved. Here, we present data showing that MM is heritable and that the transmission correlates with hyperglycemia-induced DNA hypomethylation and aberrant gene expression. Streptozocin was used to induce hyperglycemia in adult zebrafish, and then, following streptozocin withdrawal, a recovery phase was allowed to reestablish a euglycemic state. Blood glucose and serum insu...

  15. DNA methylation analysis of the angiotensin converting enzyme (ACE gene in major depression.

    Peter Zill

    Full Text Available BACKGROUND: The angiotensin converting enzyme (ACE has been repeatedly discussed as susceptibility factor for major depression (MD and the bi-directional relation between MD and cardiovascular disorders (CVD. In this context, functional polymorphisms of the ACE gene have been linked to depression, to antidepressant treatment response, to ACE serum concentrations, as well as to hypertension, myocardial infarction and CVD risk markers. The mostly investigated ACE Ins/Del polymorphism accounts for ~40%-50% of the ACE serum concentration variance, the remaining half is probably determined by other genetic, environmental or epigenetic factors, but these are poorly understood. MATERIALS AND METHODS: The main aim of the present study was the analysis of the DNA methylation pattern in the regulatory region of the ACE gene in peripheral leukocytes of 81 MD patients and 81 healthy controls. RESULTS: We detected intensive DNA methylation within a recently described, functional important region of the ACE gene promoter including hypermethylation in depressed patients (p = 0.008 and a significant inverse correlation between the ACE serum concentration and ACE promoter methylation frequency in the total sample (p = 0.02. Furthermore, a significant inverse correlation between the concentrations of the inflammatory CVD risk markers ICAM-1, E-selectin and P-selectin and the degree of ACE promoter methylation in MD patients could be demonstrated (p = 0.01 - 0.04. CONCLUSION: The results of the present study suggest that aberrations in ACE promoter DNA methylation may be an underlying cause of MD and probably a common pathogenic factor for the bi-directional relationship between MD and cardiovascular disorders.

  16. Glioblastoma and the significance of MGMT gene methylation

    Payam Izadpanahi; Kazem Anvari; Mitra Fazl Ersi

    2014-01-01

    In this research Glioblastoma has been studied as one of the most common brain tumors and a short review of the available therapeutic methods have presented including surgery, radiotherapy, chemotherapy and particularly adjuvant chemotherapy with temozolomide, as the most effective developed treatment. Moreover, MGMT gene promoter methylation has been introduced as an important predictive factor of treatment response to temozolamide. The different mechanisms of methylation and the availableli...

  17. Methylation of Gene CHFR Promoter in Acute Leukemia Cells

    GONG Hui; LIU Wengli; ZHOU Jianfeng; XU Huizhen

    2005-01-01

    Summary: In order to explore whether gene CHFR was inactivated by methylation in leukemia cells, the expression of CHFR was examined before and after treatment with demethylation agent in Molt-4, Jurkat and U937 leukemia cell lines by means of RT-PCR. The methylation of promoter in Molt-4, Jurkat and U937 cells as well as 41 acute leukemia patients was analyzed by MS-PCR. The results showed that methylation of CHFR promoter was inactivated and could be reversed by treatment with a demethylating agent in Molt-4, Jurkat and U937. CHFR promoter methylation was detected in 39 % of acute leukemia patients. There was no difference in incidence of CHFR promoter methylation between acute myelocytic leukemia and acute lymphocytic leukemia. In conclusion, CHFR is frequently inactivated in acute leukemia and is a good candidate for the leukemia supper gene. By affecting mitotic checkpoint function, CHFR inactivation likely plays a key role in tumorigenesis in acute leukemia. Moreover, the methylation of gene CHFR appears to be a good index with which to predict the sensitivity of acute leukemia to microtubule inhibitors.

  18. Reasons of carcinogenesis indicate a big-bang inside: a hypothesis for the aberration of DNA methylation.

    Roy, A; Roy Chattopadhyay, N

    2013-07-01

    Cancer involves various sets of altered gene functions which embrace all the three basic mechanisms of regulation of gene expression. However, no common mechanism is inferred till date for this versatile disease and thus no full proof remedy can be offered. Here we show that the basic mechanisms are interlinked and indicate towards one of those mechanisms as being the superior one; the methylation of cytosines in specific DNA sequences, for the initiation and maintenance of carcinogenesis. The analyses of the previous reports and the nucleotide sequences of the DNA methyltransferases strongly support the assumption that the mutation(s) in the DNA-binding site(s) of DNA-methyltransferases acts as a master regulator; though it continues the cycle from mutation to repair to methylation. We anticipate that our hypothesis will start a line of study for the proposal of a treatment regime for cancers by introducing wild type methyltransferases in the diseased cells and/or germ cells, and/or by targeting ligands to the altered binding domain(s) where a mutation in the concerned enzyme(s) is seen. PMID:23623297

  19. Amyloid protein-mediated differential DNA methylation status regulates gene expression in Alzheimer’s disease model cell line

    Highlights: ► Genome-wide DNA methylation pattern in Alzheimer’s disease model cell line. ► Integrated analysis of CpG methylation and mRNA expression profiles. ► Identify three Swedish mutant target genes; CTIF, NXT2 and DDR2 gene. ► The effect of Swedish mutation on alteration of DNA methylation and gene expression. -- Abstract: The Swedish mutation of amyloid precursor protein (APP-sw) has been reported to dramatically increase beta amyloid production through aberrant cleavage at the beta secretase site, causing early-onset Alzheimer’s disease (AD). DNA methylation has been reported to be associated with AD pathogenesis, but the underlying molecular mechanism of APP-sw-mediated epigenetic alterations in AD pathogenesis remains largely unknown. We analyzed genome-wide interplay between promoter CpG DNA methylation and gene expression in an APP-sw-expressing AD model cell line. To identify genes whose expression was regulated by DNA methylation status, we performed integrated analysis of CpG methylation and mRNA expression profiles, and identified three target genes of the APP-sw mutant; hypomethylated CTIF (CBP80/CBP20-dependent translation initiation factor) and NXT2 (nuclear exporting factor 2), and hypermethylated DDR2 (discoidin domain receptor 2). Treatment with the demethylating agent 5-aza-2′-deoxycytidine restored mRNA expression of these three genes, implying methylation-dependent transcriptional regulation. The profound alteration in the methylation status was detected at the −435, −295, and −271 CpG sites of CTIF, and at the −505 to −341 region in the promoter of DDR2. In the promoter region of NXT2, only one CpG site located at −432 was differentially unmethylated in APP-sw cells. Thus, we demonstrated the effect of the APP-sw mutation on alteration of DNA methylation and subsequent gene expression. This epigenetic regulatory mechanism may contribute to the pathogenesis of AD.

  20. Correlation between ECT2 gene expression and methylation change of ECT2 promoter region in pancreatic cancer

    Mang-Li Zhang; Sen Lu; Lin Zhou; Shu-Sen Zheng

    2008-01-01

    BACKGROUND: Pancreatic cancer is closely related to epigenetic abnormality. The epithelial cell transforming sequence 2 gene (ECT2) plays a critical role in Rho activation during cytokinesis, and thus may play a role in the pathogenesis of pancreatic cancer. In this study, we investigated the relationships between aberrant expression and epigenetic changes of the ECT2 gene in pancreatic cancer. METHODS: Four cell lines (PANC-1, Colo357, T3M-4 and PancTuⅠ) and pancreatic ductal adenocarcinoma (PDAC) tissues were used for mRNA detection. After restriction isoschizomer endonucleases (MspⅠ/HpaⅡ) were used to digest the DNA sequence (5'-CCGG-3'), PCR was made to amplify the product. And RT-PCR was applied to determine the expression of the gene. RESULTS: The mRNA expression of the ECT2 gene was higher in pancreatic tumor tissue than in normal tissue. The gene was also expressed in the 4 PDAC cell lines. The methylation states of the upstream regions of the ECT2 gene were almost identical in normal, tumor pancreatic tissues, and the 4 PDAC cell lines. Some of the 5'-CCGG-3' areas in the upstream region of ECT2 were methylated, while others were unmethylated. CONCLUSIONS: The oncogene ECT2 is overexpressed in pancreatic tumor tissues as veriifed by RT-PCR detection. The methylation status of DNA in promoter areas is involved in the gene expression, along with other factors, in pancreatic cancer.

  1. Control of Glycosylation-Related Genes by DNA Methylation: the Intriguing Case of the B3GALT5 Gene and Its Distinct Promoters

    Marco Trinchera

    2014-08-01

    Full Text Available Glycosylation is a metabolic pathway consisting of the enzymatic modification of proteins and lipids through the stepwise addition of sugars that gives rise to glycoconjugates. To determine the full complement of glycoconjugates that cells produce (the glycome, a variety of genes are involved, many of which are regulated by DNA methylation. The aim of the present review is to briefly describe some relevant examples of glycosylation-related genes whose DNA methylation has been implicated in their regulation and to focus on the intriguing case of a glycosyltransferase gene (B3GALT5. Aberrant promoter methylation is frequently at the basis of their modulation in cancer, but in the case of B3GALT5, at least two promoters are involved in regulation, and a complex interplay is reported to occur between transcription factors, chromatin remodelling and DNA methylation of typical CpG islands or even of other CpG dinucleotides. Transcription of the B3GALT5 gene underwent a particular evolutionary fate, so that promoter hypermethylation, acting on one transcript, and hypomethylation of other sequences, acting on the other, cooperate on one gene to obtain full cancer-associated silencing. The findings may also help in unravelling the complex origin of serum CA19.9 antigen circulating in some patients.

  2. DNA methylation profiling in doxorubicin treated primary locally advanced breast tumours identifies novel genes associated with survival and treatment response

    Børresen-Dale Anne-Lise

    2010-03-01

    Full Text Available Abstract Background Breast cancer is the most frequent cancer in women and consists of a heterogeneous collection of diseases with distinct histopathological, genetic and epigenetic characteristics. In this study, we aimed to identify DNA methylation based biomarkers to distinguish patients with locally advanced breast cancer who may benefit from neoadjuvant doxorubicin treatment. Results We investigated quantitatively the methylation patterns in the promoter regions of 14 genes (ABCB1, ATM, BRCA1, CDH3, CDKN2A, CXCR4, ESR1, FBXW7, FOXC1, GSTP1, IGF2, HMLH1, PPP2R2B, and PTEN in 75 well-described pre-treatment samples from locally advanced breast cancer and correlated the results to the available clinical and molecular parameters. Six normal breast tissues were used as controls and 163 unselected breast cancer cases were used to validate associations with histopathological and clinical parameters. Aberrant methylation was detected in 9 out of the 14 genes including the discovery of methylation at the FOXC1 promoter. Absence of methylation at the ABCB1 promoter correlated with progressive disease during doxorubicin treatment. Most importantly, the DNA methylation status at the promoters of GSTP1, FOXC1 and ABCB1 correlated with survival, whereby the combination of methylated genes improved the subdivision with respect to the survival of the patients. In multivariate analysis GSTP1 and FOXC1 methylation status proved to be independent prognostic markers associated with survival. Conclusions Quantitative DNA methylation profiling is a powerful tool to identify molecular changes associated with specific phenotypes. Methylation at the ABCB1 or GSTP1 promoter improved overall survival probably due to prolonged availability and activity of the drug in the cell while FOXC1 methylation might be a protective factor against tumour invasiveness. FOXC1 proved to be general prognostic factor, while ABCB1 and GSTP1 might be predictive factors for the response

  3. Thrombospondin-4 is a putative tumour-suppressor gene in colorectal cancer that exhibits age-related methylation

    Thrombospondin-4 (THBS4) is a member of the extracellular calcium-binding protein family and is involved in cell adhesion and migration. The aim of this study was to evaluate the potential role of deregulation of THBS4 expression in colorectal carcinogenesis. Of particular interest was the possible silencing of expression by methylation of the CpG island in the gene promoter. Fifty-five sporadic colorectal tumours stratified for the CpG Island Methylator Phenotype (CIMP) were studied. Immunohistochemical staining of THBS4 protein was assessed in normal and tumour specimens. Relative levels of THBS4 transcript expression in matched tumours and normal mucosa were also determined by quantitative RT-PCR. Colony forming ability was examined in 8 cell lines made to overexpress THBS4. Aberrant promoter hypermethylation was investigated as a possible mechanism of gene disruption using MethyLight. Methylation was also assessed in the normal colonic tissue of 99 patients, with samples biopsied from four regions along the length of the colon. THBS4 expression was significantly lower in tumour tissue than in matched normal tissue. Immunohistochemical examination demonstrated that THBS4 protein was generally absent from normal epithelial cells and tumours, but was occasionally expressed at low levels in the cytoplasm towards the luminal surface in vesicular structures. Forced THBS4 over-expression caused a 50-60% repression of tumour colony growth in all eight cell lines examined compared to control cell lines. Tumours exhibited significantly higher levels of methylation than matched normal mucosa, and THBS4 methylation correlated with the CpG island methylator phenotype. There was a trend towards decreased gene expression in tumours exhibiting high THBS4 methylation, but the correlation was not significant. THBS4 methylation was detectable in normal mucosal biopsies where it correlated with increasing patient age and negatively with the occurrence of adenomas elsewhere in the

  4. Analysis of genomic aberrations and gene expression profiling identifies novel lesions and pathways in myeloproliferative neoplasms

    Polycythemia vera (PV), essential thrombocythemia and primary myelofibrosis, are myeloproliferative neoplasms (MPNs) with distinct clinical features and are associated with the JAK2V617F mutation. To identify genomic anomalies involved in the pathogenesis of these disorders, we profiled 87 MPN patients using Affymetrix 250K single-nucleotide polymorphism (SNP) arrays. Aberrations affecting chr9 were the most frequently observed and included 9pLOH (n=16), trisomy 9 (n=6) and amplifications of 9p13.3–23.3 (n=1), 9q33.1–34.13 (n=1) and 9q34.13 (n=6). Patients with trisomy 9 were associated with elevated JAK2V617F mutant allele burden, suggesting that gain of chr9 represents an alternative mechanism for increasing JAK2V617F dosage. Gene expression profiling of patients with and without chr9 abnormalities (+9, 9pLOH), identified genes potentially involved in disease pathogenesis including JAK2, STAT5B and MAPK14. We also observed recurrent gains of 1p36.31–36.33 (n=6), 17q21.2–q21.31 (n=5) and 17q25.1–25.3 (n=5) and deletions affecting 18p11.31–11.32 (n=8). Combined SNP and gene expression analysis identified aberrations affecting components of a non-canonical PRC2 complex (EZH1, SUZ12 and JARID2) and genes comprising a ‘HSC signature' (MLLT3, SMARCA2 and PBX1). We show that NFIB, which is amplified in 7/87 MPN patients and upregulated in PV CD34+ cells, protects cells from apoptosis induced by cytokine withdrawal

  5. Clinical Omics Analysis of Colorectal Cancer Incorporating Copy Number Aberrations and Gene Expression Data

    Tsuyoshi Yoshida

    2010-07-01

    Full Text Available Background: Colorectal cancer (CRC is one of the most frequently occurring cancers in Japan, and thus a wide range of methods have been deployed to study the molecular mechanisms of CRC. In this study, we performed a comprehensive analysis of CRC, incorporating copy number aberration (CRC and gene expression data. For the last four years, we have been collecting data from CRC cases and organizing the information as an “omics” study by integrating many kinds of analysis into a single comprehensive investigation. In our previous studies, we had experienced difficulty in finding genes related to CRC, as we observed higher noise levels in the expression data than in the data for other cancers. Because chromosomal aberrations are often observed in CRC, here, we have performed a combination of CNA analysis and expression analysis in order to identify some new genes responsible for CRC. This study was performed as part of the Clinical Omics Database Project at Tokyo Medical and Dental University. The purpose of this study was to investigate the mechanism of genetic instability in CRC by this combination of expression analysis and CNA, and to establish a new method for the diagnosis and treatment of CRC. Materials and methods: Comprehensive gene expression analysis was performed on 79 CRC cases using an Affymetrix Gene Chip, and comprehensive CNA analysis was performed using an Affymetrix DNA Sty array. To avoid the contamination of cancer tissue with normal cells, laser micro-dissection was performed before DNA/RNA extraction. Data analysis was performed using original software written in the R language. Result: We observed a high percentage of CNA in colorectal cancer, including copy number gains at 7, 8q, 13 and 20q, and copy number losses at 8p, 17p and 18. Gene expression analysis provided many candidates for CRC-related genes, but their association with CRC did not reach the level of statistical significance. The combination of CNA and gene

  6. Trichloroethylene-induced gene expression and DNA methylation changes in B6C3F1 mouse liver.

    Yan Jiang

    Full Text Available Trichloroethylene (TCE, widely used as an organic solvent in the industry, is a common contaminant in air, soil, and water. Chronic TCE exposure induced hepatocellular carcinoma in mice, and occupational exposure in humans was suggested to be associated with liver cancer. To understand the role of non-genotoxic mechanism(s for TCE action, we examined the gene expression and DNA methylation changes in the liver of B6C3F1 mice orally administered with TCE (0, 100, 500 and 1000 mg/kg b.w. per day for 5 days. After 5 days TCE treatment at a dose level of 1000 mg/kg b.w., a total of 431 differentially expressed genes were identified in mouse liver by microarray, of which 291 were up-regulated and 140 down-regulated. The expression changed genes were involved in key signal pathways including PPAR, proliferation, apoptosis and homologous recombination. Notably, the expression level of a number of vital genes involved in the regulation of DNA methylation, such as Utrf1, Tet2, DNMT1, DNMT3a and DNMT3b, were dysregulated. Although global DNA methylation change was not detected in the liver of mice exposed to TCE, the promoter regions of Cdkn1a and Ihh were found to be hypo- and hypermethylated respectively, which correlated negatively with their mRNA expression changes. Furthermore, the gene expression and DNA methylation changes induced by TCE were dose dependent. The overall data indicate that TCE exposure leads to aberrant DNA methylation changes, which might alter the expression of genes involved in the TCE-induced liver tumorgenesis.

  7. Hypomethylation and Aberrant Expression of the Glioma Pathogenesis-Related 1 Gene in Wilms Tumors

    Laxmi Chilukamarri

    2007-11-01

    Full Text Available Wilms tumors (WTs have a complex etiology, displaying genetic and epigenetic changes, including loss of imprinting (LOI and tumor suppressor gene silencing. To identify new regions of epigenetic perturbation in WTs, we screened kidney and tumor DNA using CpG island (CGI tags associated with cancer-specific DNA methylation changes. One such tag corresponded to a paralog of the glioma pathogenesis-related 1/related to testis-specific, vespid, and pathogenesis proteins 1 (GLIPR1/RTVP-1 gene, previously reported to be a tumor-suppressor gene silenced by hypermethylation in prostate cancer. Here we report methylation analysis of the GLIPR1/RTVP-1 gene in WTs and normal fetal and pediatric kidneys. Hypomethylation of the GLIPR1/RTVP-1 5'-region in WTs relative to normal tissue is observed in 21/24 (87.5% of WTs analyzed. Quantitative analysis of GLIPR1/RTVP-1 expression in 24 WTs showed elevated transcript levels in 16/24 WTs (67%, with 12 WTs displaying in excess of 20-fold overexpression relative to fetal kidney (FK control samples. Immunohistochemical analysis of FK and WT corroborates the RNA expression data and reveals high GLIPR1/RTVP-1 in WT blastemal cells together with variable levels in stromal and epithelial components. Hypomethylation is also evident in the WT precursor lesions and nephrogenic rests (NRs, supporting a role for GLIPR1/RTVP-1 deregulation early in Wilms tumorigenesis. Our data show that, in addition to gene dosage changes arising from LOI and hypermethylation-induced gene silencing, gene activation resulting from hypomethylation is also prevalent in WTs.

  8. Aberrant host immune response induced by highly virulent PRRSV identified by digital gene expression tag profiling

    Zhao Xiao

    2010-10-01

    Full Text Available Abstract Background There was a large scale outbreak of the highly pathogenic porcine reproductive and respiratory syndrome (PRRS in China and Vietnam during 2006 and 2007 that resulted in unusually high morbidity and mortality among pigs of all ages. The mechanisms underlying the molecular pathogenesis of the highly virulent PRRS virus (H-PRRSV remains unknown. Therefore, the relationship between pulmonary gene expression profiles after H-PRRSV infection and infection pathology were analyzed in this study using high-throughput deep sequencing and histopathology. Results H-PRRSV infection resulted in severe lung pathology. The results indicate that aberrant host innate immune responses to H-PRRSV and induction of an anti-apoptotic state could be responsible for the aggressive replication and dissemination of H-PRRSV. Prolific rapid replication of H-PRRSV could have triggered aberrant sustained expression of pro-inflammatory cytokines and chemokines leading to a markedly robust inflammatory response compounded by significant cell death and increased oxidative damage. The end result was severe tissue damage and high pathogenicity. Conclusions The systems analysis utilized in this study provides a comprehensive basis for better understanding the pathogenesis of H-PRRSV. Furthermore, it allows the genetic components involved in H-PRRSV resistance/susceptibility in swine populations to be identified.

  9. Methylation dependent expression of the mom gene of bacteriophage Mu: deletions downstream from the methylation sites affect expression.

    Adley, C C; Bukhari, A I

    1984-01-01

    The expression of the DNA modification gene (mom) of bacteriophage Mu requires the cellular deoxyadenosine methylase (dam) and a transactivation factor from the phage. By hypothesis, the transcription of mom is activated by methylation of three GATC sequences upstream from the mom gene. We have introduced small deletions at a fourth GATC site located about 140 base pairs downstream from the primary methylation region. Some of the deletions severely affect the mom gene expression. We propose f...

  10. Regulation of MYC gene expression by aberrant Wnt/β-catenin signaling in colorectal cancer

    Sherri; Rennoll; Gregory; Yochum

    2015-01-01

    The Wnt/β-catenin signaling pathway controls intestinal homeostasis and mutations in components of this pathway are prevalent in human colorectal cancers(CRCs).These mutations lead to inappropriate expression of genes controlled by Wnt responsive DNA elements(WREs). T-cell factor/Lymphoid enhancer factor transcription factors bind WREs and recruit the β-catenin transcriptional co-activator to activate target gene expression. Deregulated expression of the c-MYC proto-oncogene(MYC) by aberrant Wnt/β-catenin signaling drives colorectal carcinogenesis. In this review,we discuss the current literature pertaining to the identification and characterization of WREs that control oncogenic MYC expression in CRCs. A common theme has emerged whereby these WREs often map distally to the MYC genomic locus and control MYC gene expression through long-range chromatin loops with the MYC proximal promoter. We propose that by determining which of these WREs is critical for CRC pathogenesis,novel strategies can be developed to treat individuals suffering from this disease.

  11. Do aberrant crypt foci have predictive value for the occurrence of colorectal tumours? Potential of gene expression profiling in tumours

    Wijnands, M.V.W.; Erk, M.J. van; Doornbos, R.P.; Krul, C.A.M.; Woutersen, R.A.

    2004-01-01

    The effects of different dietary compounds on the formation of aberrant crypt foci (ACF) and colorectal tumours and on the expression of a selection of genes were studied in rats. Azoxymethane-treated male F344 rats were fed either a control diet or a diet containing 10% wheat bran (WB), 0.2% curcum

  12. Identification of regions correlating MGMT promoter methylation and gene expression in glioblastomas

    Everhard, Sibille; Tost, Jörg; Abdalaoui, Hafida El; Crinière, Emmanuelle; Busato, Florence; Marie, Yannick; Gut, Ivo G.; Sanson, Marc; Mokhtari, Karima; Laigle-Donadey, Florence; Hoang-Xuan, Khê; Delattre, Jean-Yves; Thillet, Joëlle

    2009-01-01

    The O6-methylguanine-DNA methyltransferase gene (MGMT) is methylated in several cancers, including gliomas. However, the functional role of cysteine-phosphate-guanine (CpG) island (CGI) methylation in MGMT silencing is still controversial. The aim of this study was to investigate whether MGMT CGI methylation correlates inversely with RNA expression of MGMT in glioblastomas and to determine the CpG region whose methylation best reflects the level of expression. The methylation level of CpG sit...

  13. THE ABERRANT PROMOTER HYPERMETHYLATION PATTERN OF THE ANTI - ANGIOGENIC TSP1 GENE IN EPITHELIAL OVARIAN CARCINOMA: AN INDIAN STUDY

    Ramesh

    2015-06-01

    Full Text Available PURPOSE: The promoter hypermethylation patterns of Thrombospodin - 1 gene in 50 EOC patients were studied and the methylation pattern was correlated with various clinic pathological parameters. METHODS: The promoter hypermethylation pattern of the TSP - 1 gene was assessed using nested PCR and Methylation specific PCR. STATISTICAL ANALYSIS: All the available data was statistically analyzed using the Chi square test or Fisher Exact Test on the SPSS software version 22.0 and a value <0.0 5 was considered statistically significant. RESULTS: Forty of the fifty ovarian carcinoma samples reported positive for methylation corresponding to a methylation frequency of 80%. A methylation frequency of 89.2%, 83.3% and 42.8% was observed in malignant , Low malignant potential (borderline and benign sample cohorts. CONCLUSION: From the results drawn from this study, it clearly shows that the anti angiogenic protein TSP - 1 is extensively hypermethylated in ovarian carcinoma and that it accumulates over t he progression of the disease from benign to malignant. As previous reports suggest that there is no evidence of mutation of this gene, promoter hypermethylation may be a crucial factor for the down regulation of the gene. Further by clubbing together the promoter hypermethylation pattern of TSP - 1 gene with hypermethylation patterns of other TSG may provide a better insight into the application of using methylation profiles of TSG as a biomarker in the detection of ovarian carcinoma.

  14. Integrated analysis of DNA methylation profiles and gene expression profiles to identify genes associated with pilocytic astrocytomas

    Zhou, Ruigang; MAN, YIGANG

    2016-01-01

    The present study performed an integral analysis of the gene expression and DNA methylation profile of pilocytic astrocytomas (PAs). Weighted gene co-expression network analysis (WGCNA) was also performed to examine and identify the genes correlated to PAs, to identify candidate therapeutic targets for the treatment of PAs. The DNA methylation profile and gene expression profile were downloaded from the Gene Expression Omnibus database. Following screening of the differentially expressed gene...

  15. Antipsychotic drugs attenuate aberrant DNA methylation of DTNBP1 (dysbindin) promoter in saliva and post-mortem brain of patients with schizophrenia and Psychotic bipolar disorder.

    Abdolmaleky, Hamid M; Pajouhanfar, Sara; Faghankhani, Masoomeh; Joghataei, Mohammad Taghi; Mostafavi, Ashraf; Thiagalingam, Sam

    2015-12-01

    Due to the lack of genetic association between individual genes and schizophrenia (SCZ) pathogenesis, the current consensus is to consider both genetic and epigenetic alterations. Here, we report the examination of DNA methylation status of DTNBP1 promoter region, one of the most credible candidate genes affected in SCZ, assayed in saliva and post-mortem brain samples. The Illumina DNA methylation profiling and bisulfite sequencing of representative samples were used to identify methylation status of the DTNBP1 promoter region. Quantitative methylation specific PCR (qMSP) was employed to assess methylation of DTNBP1 promoter CpGs flanking a SP1 binding site in the saliva of SCZ patients, their first-degree relatives and control subjects (30, 15, and 30/group, respectively) as well as in post-mortem brains of patients with SCZ and bipolar disorder (BD) versus controls (35/group). qRT-PCR was used to assess DTNBP1 expression. We found DNA hypermethylation of DTNBP1 promoter in the saliva of SCZ patients (∼12.5%, P = 0.036), particularly in drug-naïve patients (∼20%, P = 0.011), and a trend toward hypermethylation in their first-degree relatives (P = 0.085) versus controls. Analysis of post-mortem brain samples revealed an inverse correlation between DTNBP1 methylation and expression, and normalization of this epigenetic change by classic antipsychotic drugs. Additionally, BD patients with psychotic depression exhibited higher degree of methylation versus other BD patients (∼80%, P = 0.025). DTNBP1 promoter DNA methylation may become a key element in a panel of biomarkers for diagnosis, prevention, or therapy in SCZ and at risk individuals pending confirmatory studies with larger sample sizes to attain a higher degree of significance. PMID:26285059

  16. Corruption of the intra-gene DNA methylation architecture is a hallmark of cancer.

    Bartlett, Thomas E; Zaikin, Alexey; Olhede, Sofia C; West, James; Teschendorff, Andrew E; Widschwendter, Martin

    2013-01-01

    Epigenetic processes--including DNA methylation--are increasingly seen as having a fundamental role in chronic diseases like cancer. It is well known that methylation levels at particular genes or loci differ between normal and diseased tissue. Here we investigate whether the intra-gene methylation architecture is corrupted in cancer and whether the variability of levels of methylation of individual CpGs within a defined gene is able to discriminate cancerous from normal tissue, and is associated with heterogeneous tumour phenotype, as defined by gene expression. We analysed 270985 CpGs annotated to 18272 genes, in 3284 cancerous and 681 normal samples, corresponding to 14 different cancer types. In doing so, we found novel differences in intra-gene methylation pattern across phenotypes, particularly in those genes which are crucial for stem cell biology; our measures of intra-gene methylation architecture are a better determinant of phenotype than measures based on mean methylation level alone (K-S test [Formula: see text] in all 14 diseases tested). These per-gene methylation measures also represent a considerable reduction in complexity, compared to conventional per-CpG beta-values. Our findings strongly support the view that intra-gene methylation architecture has great clinical potential for the development of DNA-based cancer biomarkers. PMID:23874574

  17. The homeobox gene MEIS1 is methylated in BRAFp.V600E mutated colon tumors

    A.A. Dihal (Ashwin); A. Boot (Arnoud); E.H.J. van Roon (Eddy); M. Schrumpf (Melanie); A. Fariña-Sarasqueta (Arantza); M. Fiocco (Marta); E.C.M. Zeestraten (Eliane); P.J.K. Kuppen (Peter); H. Morreau (Hans); T. van Wezel (Tom); J.M. Boer (Judith)

    2013-01-01

    textabstractDevelopment of colorectal cancer (CRC) can occur both via gene mutations in tumor suppressor genes and oncogenes, as well as via epigenetic changes, including DNA methylation. Site-specific methylation in CRC regulates expression of tumor-associated genes. Right-sided colon tumors more f

  18. An Observational Study on Aberrant Methylation of Runx3 With the Prognosis in Chronic Atrophic Gastritis Patients.

    Zhao, Chunna; Li, Ping; Zhang, Lili; Wang, Bei; Xiao, Lili; Guo, Feng; Wei, Yueguang

    2016-05-01

    The aim of this study is to discuss whether the methylation levels of Runx3 could be used as the early biomarker for predicting the prognosis in chronic atrophic gastritis (CAG) patients. A total of 200 subjects including 60 controls without CAG (Group 1), 70 patients with mild CAG (Group 2), and 70 patients with moderate and severe CAG (Group 3) were recruited for this cross-sectional investigation in the Department of Gastroenterology in Daqing Oilfield General Hospital from July 2013 to May 2014. The MlALDI-TOF-MS was used to measure the methylation levels of Runx3 in all of the subjects. Real-time quantitative reverse transcription polymerase chain reaction and western blotting were chosen to determine the expression levels of Runx3. The correlations between methylation levels of Runx3 among these CAG patients and their prognosis were shown by logistic regression models. The results demonstrated that the methylation levels of CpG13, CpG14, and CpG15 in Runx3 were higher in Group 3 than those in Groups 1 and 2 (P <0.05), whereas the mRNA and protein expression levels of Runx3 were lower in Group 3 than those in Groups 1 and 2 (P <0.05). There were significantly negative correlations between the methylation levels of Runx3 with its expression and the healing prognosis of CAG patients. In brief, this study proved that the hypermethylation modifications of CpG13, CpG14, and CpG15 in the promoter region of Runx3 could result in the down regulation of Runx3 expression to affect the prognosis of CAG. So the methylation levels of these CpG sites in Runx3 in the peripheral blood can be used as the biomarker for predicting the healing prognosis of CAG patients. PMID:27196446

  19. DNA Methylation and Cancer Diagnosis

    Jérôme Torrisani

    2013-07-01

    Full Text Available DNA methylation is a major epigenetic modification that is strongly involved in the physiological control of genome expression. DNA methylation patterns are largely modified in cancer cells and can therefore be used to distinguish cancer cells from normal tissues. This review describes the main technologies available for the detection and the discovery of aberrantly methylated DNA patterns. It also presents the different sources of biological samples suitable for DNA methylation studies. We discuss the interest and perspectives on the use of DNA methylation measurements for cancer diagnosis through examples of methylated genes commonly documented in the literature. The discussion leads to our consideration for why DNA methylation is not commonly used in clinical practice through an examination of the main requirements that constitute a reliable biomarker. Finally, we describe the main DNA methylation inhibitors currently used in clinical trials and those that exhibit promising results.

  20. Integrated analysis of DNA methylation and gene expression reveals specific signaling pathways associated with platinum resistance in ovarian cancer

    Chung Jae

    2009-06-01

    Full Text Available Abstract Background Cisplatin and carboplatin are the primary first-line therapies for the treatment of ovarian cancer. However, resistance to these platinum-based drugs occurs in the large majority of initially responsive tumors, resulting in fully chemoresistant, fatal disease. Although the precise mechanism(s underlying the development of platinum resistance in late-stage ovarian cancer patients currently remains unknown, CpG-island (CGI methylation, a phenomenon strongly associated with aberrant gene silencing and ovarian tumorigenesis, may contribute to this devastating condition. Methods To model the onset of drug resistance, and investigate DNA methylation and gene expression alterations associated with platinum resistance, we treated clonally derived, drug-sensitive A2780 epithelial ovarian cancer cells with increasing concentrations of cisplatin. After several cycles of drug selection, the isogenic drug-sensitive and -resistant pairs were subjected to global CGI methylation and mRNA expression microarray analyses. To identify chemoresistance-associated, biological pathways likely impacted by DNA methylation, promoter CGI methylation and mRNA expression profiles were integrated and subjected to pathway enrichment analysis. Results Promoter CGI methylation revealed a positive association (Spearman correlation of 0.99 between the total number of hypermethylated CGIs and GI50 values (i.e., increased drug resistance following successive cisplatin treatment cycles. In accord with that result, chemoresistance was reversible by DNA methylation inhibitors. Pathway enrichment analysis revealed hypermethylation-mediated repression of cell adhesion and tight junction pathways and hypomethylation-mediated activation of the cell growth-promoting pathways PI3K/Akt, TGF-beta, and cell cycle progression, which may contribute to the onset of chemoresistance in ovarian cancer cells. Conclusion Selective epigenetic disruption of distinct biological

  1. A panel of genes methylated with high frequency in colorectal cancer

    The development of colorectal cancer (CRC) is accompanied by extensive epigenetic changes, including frequent regional hypermethylation particularly of gene promoter regions. Specific genes, including SEPT9, VIM1 and TMEFF2 become methylated in a high fraction of cancers and diagnostic assays for detection of cancer-derived methylated DNA sequences in blood and/or fecal samples are being developed. There is considerable potential for the development of new DNA methylation biomarkers or panels to improve the sensitivity and specificity of current cancer detection tests. Combined epigenomic methods – activation of gene expression in CRC cell lines following DNA demethylating treatment, and two novel methods of genome-wide methylation assessment – were used to identify candidate genes methylated in a high fraction of CRCs. Multiplexed amplicon sequencing of PCR products from bisulfite-treated DNA of matched CRC and non-neoplastic tissue as well as healthy donor peripheral blood was performed using Roche 454 sequencing. Levels of DNA methylation in colorectal tissues and blood were determined by quantitative methylation specific PCR (qMSP). Combined analyses identified 42 candidate genes for evaluation as DNA methylation biomarkers. DNA methylation profiles of 24 of these genes were characterised by multiplexed bisulfite-sequencing in ten matched tumor/normal tissue samples; differential methylation in CRC was confirmed for 23 of these genes. qMSP assays were developed for 32 genes, including 15 of the sequenced genes, and used to quantify methylation in tumor, adenoma and non-neoplastic colorectal tissue and from healthy donor peripheral blood. 24 of the 32 genes were methylated in >50% of neoplastic samples, including 11 genes that were methylated in 80% or more CRCs and a similar fraction of adenomas. This study has characterised a panel of 23 genes that show elevated DNA methylation in >50% of CRC tissue relative to non-neoplastic tissue. Six of these genes

  2. DNA methylation analysis in the intestinal epithelium-effect of cell separation on gene expression and methylation profile.

    Andreas C Jenke

    Full Text Available BACKGROUND: Epigenetic signatures are highly cell type specific. Separation of distinct cell populations is therefore desirable for all epigenetic studies. However, to date little information is available on whether separation protocols might influence epigenetic and/or gene expression signatures and hence might be less beneficial. We investigated the influence of two frequently used protocols to isolate intestinal epithelium cells (IECs from 6 healthy individuals. MATERIALS AND METHODS: Epithelial cells were isolated from small bowel (i.e. terminal ileum biopsies using EDTA/DTT and enzymatic release followed by magnetic bead sorting via EPCAM labeled microbeads. Effects on gene/mRNA expression were analyzed using a real time PCR based expression array. DNA methylation was assessed by pyrosequencing of bisulfite converted DNA and methylated DNA immunoprecipitation (MeDIP. RESULTS: While cell purity was >95% using both cell separation approaches, gene expression analysis revealed significantly higher mRNA levels of several inflammatory genes in EDTA/DTT when compared to enzymatically released cells. In contrast, DNA methylation of selected genes was less variable and only revealed subtle differences. Comparison of DNA methylation of the epithelial cell marker EPCAM in unseparated whole biopsy samples with separated epithelium (i.e. EPCAM positive and negative fraction demonstrated significant differences in DNA methylation between all three tissue fractions indicating cell type specific methylation patterns can be masked in unseparated tissue samples. CONCLUSIONS: Taken together, our data highlight the importance of considering the potential effect of cell separation on gene expression as well as DNA methylation signatures. The decision to separate tissue samples will therefore depend on study design and specific separation protocols.

  3. SETDB1 is involved in postembryonic DNA methylation and gene silencing in Drosophila.

    Dawei Gou

    Full Text Available DNA methylation is fundamental for the stability and activity of genomes. Drosophila melanogaster and vertebrates establish a global DNA methylation pattern of their genome during early embryogenesis. Large-scale analyses of DNA methylation patterns have uncovered revealed that DNA methylation patterns are dynamic rather than static and change in a gene-specific fashion during development and in diseased cells. However, the factors and mechanisms involved in dynamic, postembryonic DNA methylation remain unclear. Methylation of lysine 9 in histone H3 (H3-K9 by members of the Su(var3-9 family of histone methyltransferases (HMTs triggers embryonic DNA methylation in Arthropods and Chordates. Here, we demonstrate that Drosophila SETDB1 (dSETDB1 can mediate DNA methylation and silencing of genes and retrotransposons. We found that dSETDB1 tri-methylates H3-K9 and binds methylated CpA motifs. Tri-methylation of H3-K9 by dSETDB1 mediates recruitment of DNA methyltransferase 2 (Dnmt2 and Su(var205, the Drosophila ortholog of mammalian "Heterochromatin Protein 1", to target genes for dSETDB1. By enlisting Dnmt2 and Su(var205, dSETDB1 triggers DNA methylation and silencing of genes and retrotransposons in Drosophila cells. DSETDB1 is involved in postembryonic DNA methylation and silencing of Rt1b{} retrotransposons and the tumor suppressor gene retinoblastoma family protein 1 (Rb in imaginal discs. Collectively, our findings implicate dSETDB1 in postembryonic DNA methylation, provide a model for silencing of the tumor suppressor Rb, and uncover a role for cell type-specific DNA methylation in Drosophila development.

  4. Genetic analysis of DNA methylation and gene expression levels in whole blood of healthy human subjects

    van Eijk Kristel R

    2012-11-01

    Full Text Available Abstract Background The predominant model for regulation of gene expression through DNA methylation is an inverse association in which increased methylation results in decreased gene expression levels. However, recent studies suggest that the relationship between genetic variation, DNA methylation and expression is more complex. Results Systems genetic approaches for examining relationships between gene expression and methylation array data were used to find both negative and positive associations between these levels. A weighted correlation network analysis revealed that i both transcriptome and methylome are organized in modules, ii co-expression modules are generally not preserved in the methylation data and vice-versa, and iii highly significant correlations exist between co-expression and co-methylation modules, suggesting the existence of factors that affect expression and methylation of different modules (i.e., trans effects at the level of modules. We observed that methylation probes associated with expression in cis were more likely to be located outside CpG islands, whereas specificity for CpG island shores was present when methylation, associated with expression, was under local genetic control. A structural equation model based analysis found strong support in particular for a traditional causal model in which gene expression is regulated by genetic variation via DNA methylation instead of gene expression affecting DNA methylation levels. Conclusions Our results provide new insights into the complex mechanisms between genetic markers, epigenetic mechanisms and gene expression. We find strong support for the classical model of genetic variants regulating methylation, which in turn regulates gene expression. Moreover we show that, although the methylation and expression modules differ, they are highly correlated.

  5. MGMT, GATA6, CD81, DR4, and CASP8 gene promoter methylation in glioblastoma

    Methylation of promoter region is the major mechanism affecting gene expression in tumors. Recent methylome studies of brain tumors revealed a list of new epigenetically modified genes. Our aim was to study promoter methylation of newly identified epigenetically silenced genes together with already known epigenetic markers and evaluate its separate and concomitant role in glioblastoma genesis and patient outcome. The methylation status of MGMT, CD81, GATA6, DR4, and CASP8 in 76 patients with primary glioblastomas was investigated. Methylation-specific PCR reaction was performed using bisulfite treated DNA. Evaluating glioblastoma patient survival time after operation, patient data and gene methylation effect on survival was estimated using survival analysis. The overwhelming majority (97.3%) of tumors were methylated in at least one of five genes tested. In glioblastoma specimens gene methylation was observed as follows: MGMT in 51.3%, GATA6 in 68.4%, CD81 in 46.1%, DR4 in 41.3% and CASP8 in 56.8% of tumors. Methylation of MGMT was associated with younger patient age (p < 0.05), while CASP8 with older (p < 0.01). MGMT methylation was significantly more frequent event in patient group who survived longer than 36 months after operation (p < 0.05), while methylation of CASP8 was more frequent in patients who survived shorter than 36 months (p < 0.05). Cox regression analysis showed patient age, treatment, MGMT, GATA6 and CASP8 as independent predictors for glioblastoma patient outcome (p < 0.05). MGMT and GATA6 were independent predictors for patient survival in younger patients’ group, while there were no significant associations observed in older patients’ group when adjusted for therapy. High methylation frequency of tested genes shows heterogeneity of glioblastoma epigenome and the importance of MGMT, GATA6 and CASP8 genes methylation in glioblastoma patient outcome

  6. Associations between antibiotic exposure during pregnancy, birth weight and aberrant methylation at imprinted genes among offspring

    Vidal, A. C.; Murphy, S K; Murtha, A P; Schildkraut, J M; Soubry, A; Huang, Z; Neelon, S E B; Fuemmeler, B; Iversen, E; Wang, F.; Kurtzberg, J; Jirtle, R L; Hoyo, C

    2013-01-01

    Objectives: Low birth weight (LBW) has been associated with common adult-onset chronic diseases, including obesity, cardiovascular disease, type II diabetes and some cancers. The etiology of LBW is multi-factorial. However, recent evidence suggests exposure to antibiotics may also increase the risk of LBW. The mechanisms underlying this association are unknown, although epigenetic mechanisms are hypothesized. In this study, we evaluated the association between maternal antibiotic use and LBW ...

  7. miRNA Gene Promoters Are Frequent Targets of Aberrant DNA Methylation in Human Breast Cancer

    Vrba, Lukáš; Munoz-Rodriguez, J.L.; Stampfer, M.R.; Futscher, B. W.

    2013-01-01

    Roč. 8, č. 1 (2013), e54398. E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : Tumor-Suppressor * feedback loop * microRNAs Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.534, year: 2013

  8. DNA Methylation Profiles of Protease Nexin 1 (SERPINE2) Gene in Human Cell Lines

    Shan Gao; Peter A. Andreasen

    2011-01-01

    Objective: To investigated whether epigenetic mechanisms contribute to the variable expression of variable protease nexin1(PN-1) encoded by the SERPINE2 gene in different cell types. Methods: Working with 5 human cell lines, we determined the CpG methylation status within two CpG islands in the SERPINE2 gene by bisulphate sequencing and the PN-1 mRNA level by Q-RT PCR. Results: A CpG island spanning the transcription initiation site showed little methylation in 3 of the cell lines and substantial methylation in 2 of the cell lines. A CpG island covering the translation starting site showed full methylation in all investigated cell lines. Methylation within the CpG island was not randomly distributed, but showed accumulation at specific sites. However, we were not able to distinguish any patterns which related the methylation frequency to the gene expression level. Inhibition of CpG methylation with 5-aza-2′-deoxycytidine led to a several fold increase in PN-1 mRNA levels, but based on the results on CpG methylation in the CpG island spanning the transcript, the effect is most likely indirect. Conclusion: We have carefully mapped the CpG methylation pattern in two CpG islands in the 5′ part of the SERPINE2 gene without finding any obvious inverse correlation between methylation frequency and expression level.

  9. Dynamic DNA cytosine methylation in the Populus trichocarpa genome: tissue-level variation and relationship to gene expression

    Vining Kelly J

    2012-01-01

    Full Text Available Abstract Background DNA cytosine methylation is an epigenetic modification that has been implicated in many biological processes. However, large-scale epigenomic studies have been applied to very few plant species, and variability in methylation among specialized tissues and its relationship to gene expression is poorly understood. Results We surveyed DNA methylation from seven distinct tissue types (vegetative bud, male inflorescence [catkin], female catkin, leaf, root, xylem, phloem in the reference tree species black cottonwood (Populus trichocarpa. Using 5-methyl-cytosine DNA immunoprecipitation followed by Illumina sequencing (MeDIP-seq, we mapped a total of 129,360,151 36- or 32-mer reads to the P. trichocarpa reference genome. We validated MeDIP-seq results by bisulfite sequencing, and compared methylation and gene expression using published microarray data. Qualitative DNA methylation differences among tissues were obvious on a chromosome scale. Methylated genes had lower expression than unmethylated genes, but genes with methylation in transcribed regions ("gene body methylation" had even lower expression than genes with promoter methylation. Promoter methylation was more frequent than gene body methylation in all tissues except male catkins. Male catkins differed in demethylation of particular transposable element categories, in level of gene body methylation, and in expression range of genes with methylated transcribed regions. Tissue-specific gene expression patterns were correlated with both gene body and promoter methylation. Conclusions We found striking differences among tissues in methylation, which were apparent at the chromosomal scale and when genes and transposable elements were examined. In contrast to other studies in plants, gene body methylation had a more repressive effect on transcription than promoter methylation.

  10. MGMT, GATA6, CD81, DR4, and CASP8 gene promoter methylation in glioblastoma

    Skiriute Daina

    2012-06-01

    Full Text Available Abstract Background Methylation of promoter region is the major mechanism affecting gene expression in tumors. Recent methylome studies of brain tumors revealed a list of new epigenetically modified genes. Our aim was to study promoter methylation of newly identified epigenetically silenced genes together with already known epigenetic markers and evaluate its separate and concomitant role in glioblastoma genesis and patient outcome. Methods The methylation status of MGMT, CD81, GATA6, DR4, and CASP8 in 76 patients with primary glioblastomas was investigated. Methylation-specific PCR reaction was performed using bisulfite treated DNA. Evaluating glioblastoma patient survival time after operation, patient data and gene methylation effect on survival was estimated using survival analysis. Results The overwhelming majority (97.3% of tumors were methylated in at least one of five genes tested. In glioblastoma specimens gene methylation was observed as follows: MGMT in 51.3%, GATA6 in 68.4%, CD81 in 46.1%, DR4 in 41.3% and CASP8 in 56.8% of tumors. Methylation of MGMT was associated with younger patient age (p CASP8 with older (p MGMT methylation was significantly more frequent event in patient group who survived longer than 36 months after operation (p CASP8 was more frequent in patients who survived shorter than 36 months (p MGMT, GATA6 and CASP8 as independent predictors for glioblastoma patient outcome (p MGMT and GATA6 were independent predictors for patient survival in younger patients’ group, while there were no significant associations observed in older patients’ group when adjusted for therapy. Conclusions High methylation frequency of tested genes shows heterogeneity of glioblastoma epigenome and the importance of MGMT, GATA6 and CASP8 genes methylation in glioblastoma patient outcome.

  11. Correlation of MGMT promoter methylation status with gene and protein expression levels in glioblastoma

    Miyuki Uno

    2011-01-01

    Full Text Available OBJECTIVES: 1 To correlate the methylation status of the O6-methylguanine-DNA-methyltransferase (MGMT promoter to its gene and protein expression levels in glioblastoma and 2 to determine the most reliable method for using MGMT to predict the response to adjuvant therapy in patients with glioblastoma. BACKGROUND: The MGMT gene is epigenetically silenced by promoter hypermethylation in gliomas, and this modification has emerged as a relevant predictor of therapeutic response. METHODS: Fifty-one cases of glioblastoma were analyzed for MGMT promoter methylation by methylation-specific PCR and pyrosequencing, gene expression by real time polymerase chain reaction, and protein expression by immunohistochemistry. RESULTS: MGMT promoter methylation was found in 43.1% of glioblastoma by methylation-specific PCR and 38.8% by pyrosequencing. A low level of MGMT gene expression was correlated with positive MGMT promoter methylation (p = 0.001. However, no correlation was found between promoter methylation and MGMT protein expression (p = 0.297. The mean survival time of glioblastoma patients submitted to adjuvant therapy was significantly higher among patients with MGMT promoter methylation (log rank = 0.025 by methylation-specific PCR and 0.004 by pyrosequencing, and methylation was an independent predictive factor that was associated with improved prognosis by multivariate analysis. DISCUSSION AND CONCLUSION: MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.

  12. FOXA1 positively regulates gene expression by changing gene methylation status in human breast cancer MCF-7 cells

    ZHENG, LU; Qian, Bo; Tian, Duo; Tang, Tong; Wan, Shengyun; Wang, Lei; Zhu, Lixin; Geng, Xiaoping

    2015-01-01

    Objective: DNA methylation is an important epigenetic modification with tumor suppressor gene silencing in cancer. The mechanisms underlying DNA methylation patterns are still poorly understood. This study aims to evaluate the potential value of FOXA1 for controlling gene CpG island methylation in breast cancer. Methods: FOXA1 was down-regulated by transfection with siRNA and up-regulated by transfection with plasmid in MCF-7 cell lines. The DNA methylation and mRNA levels were examined by qM...

  13. Investigation of Interleukin-17 gene polymorphism on DAP-Kinase gene promoter methylation in Patients with Breast Cancer

    S Naeimi

    2016-02-01

    Full Text Available Background & Aim: Breast cancer is the most common malignancy in women . Studies have shown that increased in methylation of CpG islands (CpG island hyper methylation, CIHM, is one of the important mechanisms in gene down regulation. DAP-Kinase protein plays an important role in the process of Apoptosis. Interleukin-17 is an proinflammatory cytokine and inflammation,is one of the factors  that affect on gene methylation . the purpose of this study was to evaluate the polymorphism of the IL-17 gene promoter methylation Dap-kinase and its relationship to breast cancer. Methods: In this case - control study, A total of 40 Women with Breast cancer and 40 healthy women in Iran were examined.DNA was extracted by saluting out method and Single nucleotide Polymorphisms of the IL-17 gene were analyzed by the PCR-RFLP method and To study gene promoter methylation Dap-kinase, MSPCR method was used.data were compared in both groups by using Pearson’s chi-square and Hardy-weinberg equilibrium test. RESULTS: Results confirm the fact that, there is a relationship between DAP-kinase gene promoter methylation and breast cancer disease So that the promoter of this gene in patients than in healthy individuals was much more methylated( p0.05 Conclusion: Due to the fact, that promoter genes methylation is one of the mechanisms of epigenetic genes silencing, it seems that DAP-kinase gene promoter methylation increases is associated with the risk of breast cancer in women.

  14. Downregulation of retinoic acid receptor-β2expression is linked to aberrant methylation in esophageal squamous cell carcinoma cell lines

    Zhong-Min Liu; Fang Ding; Ming-Zhou Guo; Li-Yong Zhang; Min Wu; Zhi-Hua Liu

    2004-01-01

    AIM: To study the role of hypermethylation in the loss ofretinoic acid receptorβ2(RARβ2) in esophageal squamous cell carcinoma (ESCC).METHODS: The role of hypermethylation in RAR,β2 gene silencing in 6 ESCC cell lines was determined by methylationspecific PCR (MSP), and its methylation status was compared with RARβ2 mRNA expression by RT-PCR. The MSP results were confirmed by bisulfite sequencing of RARβ2promoter regions. RESULTS: Methylation was detected in 4 of the 6 cell lines, and the expression of RARβ2was markedly downregulated in 3 of the 4 methylated cell lines. The expression of RARβ2was restored in one RARβ2-downregulated cell line with the partial demethylation of promoter region of RARβ after 5aza-2'-deoxycytidine (5-aza-dc) treatment.CONCLUSION: The methylation of the 5' region may play an important role in the downregulation of RARβ2 in someESCC cell lines, suggesting that multiple mechanisms contribute to the loss of RARβ2expression in ESCC cell lines. This study may have clinical applications for treatment and prevention of ESCC.

  15. Differentially methylated regions of imprinted genes in prenatal, perinatal and postnatal human tissues.

    Susan K Murphy

    Full Text Available Epigenetic plasticity in relation to in utero exposures may mechanistically explain observed differences in the likelihood of developing common complex diseases including hypertension, diabetes and cardiovascular disease through the cumulative effects of subtle alterations in gene expression. Imprinted genes are essential mediators of growth and development and are characterized by differentially methylated regulatory regions (DMRs that carry parental allele-specific methylation profiles. This theoretical 50% level of methylation provides a baseline from which endogenously- or exogenously-induced deviations in methylation can be detected. We quantified DNA methylation at imprinted gene DMRs in a large panel of human conceptal tissues, in matched buccal cell specimens collected at birth and at one year of age, and in the major cell fractions of umbilical cord blood to assess the stability of methylation at these regions. DNA methylation was measured using validated pyrosequencing assays at seven DMRs regulating the IGF2/H19, DLK1/MEG3, MEST, NNAT and SGCE/PEG10 imprinted domains. DMR methylation did not significantly differ for the H19, MEST and SGCE/PEG10 DMRs across all conceptal tissues analyzed (ANOVA p>0.10. Methylation differences at several DMRs were observed in tissues from brain (IGF2 and MEG3-IG DMRs, liver (IGF2 and MEG3 DMRs and placenta (both DLK1/MEG3 DMRs and NNAT DMR. In most infants, methylation profiles in buccal cells at birth and at one year of age were comparable, as was methylation in the major cell fractions of umbilical cord blood. Several infants showed temporal deviations in methylation at multiple DMRs. Similarity of inter-individual and intra-individual methylation at some, but not all of the DMRs analyzed supports the possibility that methylation of these regions can serve as useful biosensors of exposure.

  16. Study on the polymorphisms and promoter methylation and expression of the glutathione Stransferases P1 gene in hepatocellular carcinoma

    张友才

    2006-01-01

    Objective To study the relationship between hepatocellular carcinoma (HCC) and the polymorphisms, promoter methylation, and expression of glutathione S-transferases P1 gene (GST)P1 gene. Methods Using methylation -special PCR (MSP), the methylated status of CpG islands of GSTP1 gene in tumor tissues of 53 HCC and its adjacent nontumor tissues were studied. The en-

  17. EHMT2 directs DNA methylation for efficient gene silencing in mouse embryos.

    Auclair, Ghislain; Borgel, Julie; Sanz, Lionel A; Vallet, Judith; Guibert, Sylvain; Dumas, Michael; Cavelier, Patricia; Girardot, Michael; Forné, Thierry; Feil, Robert; Weber, Michael

    2016-02-01

    The extent to which histone modifying enzymes contribute to DNA methylation in mammals remains unclear. Previous studies suggested a link between the lysine methyltransferase EHMT2 (also known as G9A and KMT1C) and DNA methylation in the mouse. Here, we used a model of knockout mice to explore the role of EHMT2 in DNA methylation during mouse embryogenesis. The Ehmt2 gene is expressed in epiblast cells but is dispensable for global DNA methylation in embryogenesis. In contrast, EHMT2 regulates DNA methylation at specific sequences that include CpG-rich promoters of germline-specific genes. These loci are bound by EHMT2 in embryonic cells, are marked by H3K9 dimethylation, and have strongly reduced DNA methylation in Ehmt2(-/-) embryos. EHMT2 also plays a role in the maintenance of germline-derived DNA methylation at one imprinted locus, the Slc38a4 gene. Finally, we show that DNA methylation is instrumental for EHMT2-mediated gene silencing in embryogenesis. Our findings identify EHMT2 as a critical factor that facilitates repressive DNA methylation at specific genomic loci during mammalian development. PMID:26576615

  18. Identification of methylated genes in salivary gland adenoid cystic carcinoma xenografts using global demethylation and methylation microarray screening

    LING, SHIZHANG; RETTIG, ELENI M.; TAN, MARIETTA; CHANG, XIAOFEI; WANG, ZHIMING; BRAIT, MARIANA; BISHOP, JUSTIN A.; FERTIG, ELANA J.; CONSIDINE, MICHAEL; WICK, MICHAEL J.; HA, PATRICK K.

    2016-01-01

    Salivary gland adenoid cystic carcinoma (ACC) is a rare head and neck malignancy without molecular biomarkers that can be used to predict the chemotherapeutic response or prognosis of ACC. The regulation of gene expression of oncogenes and tumor suppressor genes (TSGs) through DNA promoter methylation may play a role in the carcinogenesis of ACC. To identify differentially methylated genes in ACC, a global demethylating agent, 5-aza-2′-deoxycytidine (5-AZA) was utilized to unmask putative TSG silencing in ACC xenograft models in mice. Fresh xenografts were passaged, implanted in triplicate in mice that were treated with 5-AZA daily for 28 days. These xenografts were then evaluated for genome-wide DNA methylation patterns using the Illumina Infinium HumanMethylation27 BeadChip array. Validation of the 32 candidate genes was performed by bisulfite sequencing (BS-seq) in a separate cohort of 6 ACC primary tumors and 6 normal control salivary gland tissues. Hypermethylation was identified in the HCN2 gene promoter in all 6 control tissues, but hypomethylation was found in all 6 ACC tumor tissues. Quantitative validation of HCN2 promoter methylation level in the region detected by BS-seq was performed in a larger cohort of primary tumors (n=32) confirming significant HCN2 hypomethylation in ACCs compared with normal samples (n=10; P=0.04). HCN2 immunohistochemical staining was performed on an ACC tissue microarray. HCN2 staining intensity and H-score, but not percentage of the positively stained cells, were significantly stronger in normal tissues than those of ACC tissues. With our novel screening and sequencing methods, we identified several gene candidates that were methylated. The most significant of these genes, HCN2, was actually hypomethylated in tumors. However, promoter methylation status does not appear to be a major determinant of HCN2 expression in normal and ACC tissues. HCN2 hypomethylation is a biomarker of ACC and may play an important role in the

  19. The impact of endurance exercise on global and AMPK gene-specific DNA methylation.

    King-Himmelreich, Tanya S; Schramm, Stefanie; Wolters, Miriam C; Schmetzer, Julia; Möser, Christine V; Knothe, Claudia; Resch, Eduard; Peil, Johannes; Geisslinger, Gerd; Niederberger, Ellen

    2016-05-27

    Alterations in gene expression as a consequence of physical exercise are frequently described. The mechanism of these regulations might depend on epigenetic changes in global or gene-specific DNA methylation levels. The AMP-activated protein kinase (AMPK) plays a key role in maintenance of energy homeostasis and is activated by increases in the AMP/ATP ratio as occurring in skeletal muscles after sporting activity. To analyze whether exercise has an impact on the methylation status of the AMPK promoter, we determined the AMPK methylation status in human blood samples from patients before and after sporting activity in the context of rehabilitation as well as in skeletal muscles of trained and untrained mice. Further, we examined long interspersed nuclear element 1 (LINE-1) as indicator of global DNA methylation changes. Our results revealed that light sporting activity in mice and humans does not alter global DNA methylation but has an effect on methylation of specific CpG sites in the AMPKα2 gene. These regulations were associated with a reduced AMPKα2 mRNA and protein expression in muscle tissue, pointing at a contribution of the methylation status to AMPK expression. Taken together, these results suggest that exercise influences AMPKα2 gene methylation in human blood and eminently in the skeletal muscle of mice and therefore might repress AMPKα2 gene expression. PMID:27103439

  20. MicroRNA alterations and associated aberrant DNA methylation patterns across multiple sample types in oral squamous cell carcinoma

    Wiklund, Erik Digman; Gao, Shan; Hulf, Toby;

    2011-01-01

    MicroRNA (miRNA) expression is broadly altered in cancer, but few studies have investigated miRNA deregulation in oral squamous cell carcinoma (OSCC). Epigenetic mechanisms are involved in the regulation of >30 miRNA genes in a range of tissues, and we aimed to investigate this further in OSCC....

  1. Defining the cutoff value of MGMT gene promoter methylation and its predictive capacity in glioblastoma.

    Brigliadori, Giovanni; Foca, Flavia; Dall'Agata, Monia; Rengucci, Claudia; Melegari, Elisabetta; Cerasoli, Serenella; Amadori, Dino; Calistri, Daniele; Faedi, Marina

    2016-06-01

    Despite advances in the treatment of glioblastoma (GBM), median survival is 12-15 months. O6-methylguanine-DNA methyltransferase (MGMT) gene promoter methylation status is acknowledged as a predictive marker for temozolomide (TMZ) treatment. When MGMT promoter values fall into a "methylated" range, a better response to chemotherapy is expected. However, a cutoff that discriminates between "methylated" and "unmethylated" status has yet to be defined. We aimed to identify the best cutoff value and to find out whether variability in methylation profiles influences the predictive capacity of MGMT promoter methylation. Data from 105 GBM patients treated between 2008 and 2013 were analyzed. MGMT promoter methylation status was determined by analyzing 10 CpG islands by pyrosequencing. Patients were treated with radiotherapy followed by TMZ. MGMT promoter methylation status was classified into unmethylated 0-9 %, methylated 10-29 % and methylated 30-100 %. Statistical analysis showed that an assumed methylation cutoff of 9 % led to an overestimation of responders. All patients in the 10-29 % methylation group relapsed before the 18-month evaluation. Patients with a methylation status ≥30 % showed a median overall survival of 25.2 months compared to 15.2 months in all other patients, confirming this value as the best methylation cutoff. Despite wide variability among individual profiles, single CpG island analysis did not reveal any correlation between single CpG island methylation values and relapse or death. Specific CpG island methylation status did not influence the predictive value of MGMT. The predictive role of MGMT promoter methylation was maintained only with a cutoff value ≥30 %. PMID:27029617

  2. Genome-wide age-related changes in DNA methylation and gene expression in human PBMCs.

    Steegenga, Wilma T; Boekschoten, Mark V; Lute, Carolien; Hooiveld, Guido J; de Groot, Philip J; Morris, Tiffany J; Teschendorff, Andrew E; Butcher, Lee M; Beck, Stephan; Müller, Michael

    2014-06-01

    Aging is a progressive process that results in the accumulation of intra- and extracellular alterations that in turn contribute to a reduction in health. Age-related changes in DNA methylation have been reported before and may be responsible for aging-induced changes in gene expression, although a causal relationship has yet to be shown. Using genome-wide assays, we analyzed age-induced changes in DNA methylation and their effect on gene expression with and without transient induction with the synthetic transcription modulating agent WY14,643. To demonstrate feasibility of the approach, we isolated peripheral blood mononucleated cells (PBMCs) from five young and five old healthy male volunteers and cultured them with or without WY14,643. Infinium 450K BeadChip and Affymetrix Human Gene 1.1 ST expression array analysis revealed significant differential methylation of at least 5 % (ΔYO > 5 %) at 10,625 CpG sites between young and old subjects, but only a subset of the associated genes were also differentially expressed. Age-related differential methylation of previously reported epigenetic biomarkers of aging including ELOVL2, FHL2, PENK, and KLF14 was confirmed in our study, but these genes did not display an age-related change in gene expression in PBMCs. Bioinformatic analysis revealed that differentially methylated genes that lack an age-related expression change predominantly represent genes involved in carcinogenesis and developmental processes, and expression of most of these genes were silenced in PBMCs. No changes in DNA methylation were found in genes displaying transiently induced changes in gene expression. In conclusion, aging-induced differential methylation often targets developmental genes and occurs mostly without change in gene expression. PMID:24789080

  3. Genome-wide DNA methylation and gene expression patterns provide insight into polycystic ovary syndrome development

    Wang, Xiu-Xia; Wei, Jing-Zan; Jiao, Jiao; Jiang, Shu-Yi; Yu, Da-hai; Li, Da

    2014-01-01

    Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women. However, the epigenetic mechanism involved in PCOS progression remains largely unknown. Here, combining the DNA methylation profiling together with transcriptome analysis, we showed that (i) there were 7929 differentially methylated CpG sites (β > 0.1, P 1.5, P < 0.005) in PCOS compared to normal ovaries; (ii) 54 genes were identified with methylated...

  4. Pancreatic Cancer Patient Survival Correlates with DNA Methylation of Pancreas Development Genes

    Thompson, Michael J.; Rubbi, Liudmilla; Dawson, David W.; Donahue, Timothy R; Pellegrini, Matteo

    2015-01-01

    DNA methylation is an epigenetic mark associated with regulation of transcription and genome structure. These markers have been investigated in a variety of cancer settings for their utility in differentiating normal tissue from tumor tissue. Here, we examine the direct correlation between DNA methylation and patient survival. We find that changes in the DNA methylation of key pancreatic developmental genes are strongly associated with patient survival.

  5. Integrated analysis of DNA methylation profiles and gene expression profiles to identify genes associated with pilocytic astrocytomas

    ZHOU, RUIGANG; MAN, YIGANG

    2016-01-01

    The present study performed an integral analysis of the gene expression and DNA methylation profile of pilocytic astrocytomas (PAs). Weighted gene co-expression network analysis (WGCNA) was also performed to examine and identify the genes correlated to PAs, to identify candidate therapeutic targets for the treatment of PAs. The DNA methylation profile and gene expression profile were downloaded from the Gene Expression Omnibus database. Following screening of the differentially expressed genes (DEGs) and differentially methylated regions (DMRs), respectively, integrated analysis of the DEGs and DMRs was performed to detect their correlation. Subsequently, the WGCNA algorithm was applied to identify the significant modules and construct the co-expression network associated with PAs. Furthermore, Gene Ontology enrichment analysis of the associated genes was performed using the Database for Annotation, Visualization and Integrated Discovery. A total number of 2,259 DEGs and 235 DMRs were screened out. Integrated analysis revealed that 30 DEGs were DMRs with prominent negative correlation (cor=−0.82; P=0.02). Based on the DEGs, the gene co-expression network was constructed, and nine network modules associated with PAs were identified. The functional analysis results showed that genes relevant to PAs were closely associated with cell differentiation modulation. The screened PA-associated genes were significantly different at the expression and methylation levels. These genes may be used as reliable candidate target genes for the treatment of PAs. PMID:26934913

  6. Integrated analysis of DNA methylation profiles and gene expression profiles to identify genes associated with pilocytic astrocytomas.

    Zhou, Ruigang; Man, Yigang

    2016-04-01

    The present study performed an integral analysis of the gene expression and DNA methylation profile of pilocytic astrocytomas (PAs). Weighted gene co-expression network analysis (WGCNA) was also performed to examine and identify the genes correlated to PAs, to identify candidate therapeutic targets for the treatment of PAs. The DNA methylation profile and gene expression profile were downloaded from the Gene Expression Omnibus database. Following screening of the differentially expressed genes (DEGs) and differentially methylated regions (DMRs), respectively, integrated analysis of the DEGs and DMRs was performed to detect their correlation. Subsequently, the WGCNA algorithm was applied to identify the significant modules and construct the co‑expression network associated with PAs. Furthermore, Gene Ontology enrichment analysis of the associated genes was performed using the Database for Annotation, Visualization and Integrated Discovery. A total number of 2,259 DEGs and 235 DMRs were screened out. Integrated analysis revealed that 30 DEGs were DMRs with prominent negative correlation (cor=‑0.82; P=0.02). Based on the DEGs, the gene co‑expression network was constructed, and nine network modules associated with PAs were identified. The functional analysis results showed that genes relevant to PAs were closely associated with cell differentiation modulation. The screened PA-associated genes were significantly different at the expression and methylation levels. These genes may be used as reliable candidate target genes for the treatment of PAs. PMID:26934913

  7. Methylation-sensitive linking libraries enhance gene-enriched sequencing of complex genomes and map DNA methylation domains

    Bharti Arvind K

    2008-12-01

    Full Text Available Abstract Background Many plant genomes are resistant to whole-genome assembly due to an abundance of repetitive sequence, leading to the development of gene-rich sequencing techniques. Two such techniques are hypomethylated partial restriction (HMPR and methylation spanning linker libraries (MSLL. These libraries differ from other gene-rich datasets in having larger insert sizes, and the MSLL clones are designed to provide reads localized to "epigenetic boundaries" where methylation begins or ends. Results A large-scale study in maize generated 40,299 HMPR sequences and 80,723 MSLL sequences, including MSLL clones exceeding 100 kb. The paired end reads of MSLL and HMPR clones were shown to be effective in linking existing gene-rich sequences into scaffolds. In addition, it was shown that the MSLL clones can be used for anchoring these scaffolds to a BAC-based physical map. The MSLL end reads effectively identified epigenetic boundaries, as indicated by their preferential alignment to regions upstream and downstream from annotated genes. The ability to precisely map long stretches of fully methylated DNA sequence is a unique outcome of MSLL analysis, and was also shown to provide evidence for errors in gene identification. MSLL clones were observed to be significantly more repeat-rich in their interiors than in their end reads, confirming the correlation between methylation and retroelement content. Both MSLL and HMPR reads were found to be substantially gene-enriched, with the SalI MSLL libraries being the most highly enriched (31% align to an EST contig, while the HMPR clones exhibited exceptional depletion of repetitive DNA (to ~11%. These two techniques were compared with other gene-enrichment methods, and shown to be complementary. Conclusion MSLL technology provides an unparalleled approach for mapping the epigenetic status of repetitive blocks and for identifying sequences mis-identified as genes. Although the types and natures of

  8. Methylation of a panel of genes in peripheral blood leukocytes is associated with colorectal cancer.

    Luo, Xiang; Huang, Rong; Sun, Hongru; Liu, Yupeng; Bi, Haoran; Li, Jing; Yu, Hongyuan; Sun, Jiamei; Lin, Shangqun; Cui, Binbin; Zhao, Yashuang

    2016-01-01

    The relationship between the DNA methylation status of the CpG islands of multiple genes in blood leukocytes in CRC susceptibility and prognosis, as well as possible interactions with dietary factors on CRC risk are unclear. We carried out a case-control study including 421 CRC patients and 506 controls to examine the associations between six genes (AOX-1, RARB2, RERG, ADAMTS9, IRF4, and FOXE-1), multiple CpG site methylation (MCSM) and susceptibility to CRC. High-level MCSM (MCSM-H) was defined as methylation of greater than or equal to 2 of 5 candidate genes (except for RARB2); low-level MCSM (MCSM-L) was when 1 candidate gene was methylated; non-MCSM was when none of the candidate genes were methylated. Blood cell-derived DNA methylation status was detected using methylation-sensitive high-resolution melting analysis. The hypermethylation status of each individual gene was statistically significantly associated with CRC. MCSM status was also associated with CRC (OR = 1.54, 95% CI: 1.15-2.05, P = 0.004). We observed interactions between a high level of dietary intake of cereals, pungent food, and stewed fish with brown sauce, age (older than 60 yrs), smoking and hypermethylation on risk of CRC. MCSM in peripheral blood DNA may be an important biomarker for susceptibility to CRC. PMID:27453436

  9. Methylation and Expression of Immune and Inflammatory Genes in the Offspring of Bariatric Bypass Surgery Patients

    Frédéric Guénard

    2013-01-01

    Full Text Available Background. Maternal obesity, excess weight gain and overnutrition during pregnancy increase risks of obesity, type 2 diabetes mellitus, and cardiovascular disease in the offspring. Maternal biliopancreatic diversion is an effective treatment for severe obesity and is beneficial for offspring born after maternal surgery (AMS. These offspring exhibit lower severe obesity prevalence and improved cardiometabolic risk factors including inflammatory marker compared to siblings born before maternal surgery (BMS. Objective. To assess relationships between maternal bariatric surgery and the methylation/expression of genes involved in the immune and inflammatory pathways. Methods. A differential gene methylation analysis was conducted in a sibling cohort of 25 BMS and 25 AMS offspring from 20 mothers. Following differential gene expression analysis (23 BMS and 23 AMS, pathway analysis was conducted. Correlations between gene methylation/expression and circulating inflammatory markers were computed. Results. Five immune and inflammatory pathways with significant overrepresentation of both differential gene methylation and expression were identified. In the IL-8 pathway, gene methylation correlated with both gene expression and plasma C-reactive protein levels. Conclusion. These results suggest that improvements in cardiometabolic risk markers in AMS compared to BMS offspring may be mediated through differential methylation of genes involved in immune and inflammatory pathways.

  10. Methylation profiling of 48 candidate genes in tumor and matched normal tissues from breast cancer patients.

    Li, Zibo; Guo, Xinwu; Wu, Yepeng; Li, Shengyun; Yan, Jinhua; Peng, Limin; Xiao, Zhi; Wang, Shouman; Deng, Zhongping; Dai, Lizhong; Yi, Wenjun; Xia, Kun; Tang, Lili; Wang, Jun

    2015-02-01

    Gene-specific methylation alterations in breast cancer have been suggested to occur early in tumorigenesis and have the potential to be used for early detection and prevention. The continuous increase in worldwide breast cancer incidences emphasizes the urgent need for identification of methylation biomarkers for early cancer detection and patient stratification. Using microfluidic PCR-based target enrichment and next-generation bisulfite sequencing technology, we analyzed methylation status of 48 candidate genes in paired tumor and normal tissues from 180 Chinese breast cancer patients. Analysis of the sequencing results showed 37 genes differentially methylated between tumor and matched normal tissues. Breast cancer samples with different clinicopathologic characteristics demonstrated distinct profiles of gene methylation. The methylation levels were significantly different between breast cancer subtypes, with basal-like and luminal B tumors having the lowest and the highest methylation levels, respectively. Six genes (ACADL, ADAMTSL1, CAV1, NPY, PTGS2, and RUNX3) showed significant differential methylation among the 4 breast cancer subtypes and also between the ER +/ER- tumors. Using unsupervised hierarchical clustering analysis, we identified a panel of 13 hypermethylated genes as candidate biomarkers that performed a high level of efficiency for cancer prediction. These 13 genes included CST6, DBC1, EGFR, GREM1, GSTP1, IGFBP3, PDGFRB, PPM1E, SFRP1, SFRP2, SOX17, TNFRSF10D, and WRN. Our results provide evidence that well-defined DNA methylation profiles enable breast cancer prediction and patient stratification. The novel gene panel might be a valuable biomarker for early detection of breast cancer. PMID:25636590

  11. Methylation and silencing of the retinoic acid receptor-β2 gene in cervical cancer

    Expression of the retinoic acid receptor β2 (RAR-β2), a putative tumor suppressor gene, is reduced in various human cancers, including squamous cell carcinomas (SCC) of the uterine cervix. The mechanism of the inhibition of RAR-β2 expression remains obscure. We examined whether methylation of RAR-β2 gene could be responsible for this silencing in cervical SCC. Expression of RAR-β2 mRNA and methylation status of the 5' region of RAR-β2 gene were examined in 20 matched specimens from patients with cervical SCC and in three cervical cancer cell lines by Northern blot analysis and methylation-specific PCR (MSP) assay or Southern blot analysis respectively. In 8 out 20 cervical SCC (40%) the levels of RAR-β2 mRNA were decreased or undetectable in comparison with non-neoplastic cervix tissues. All 8 tumors with reduced levels of RAR-β2 mRNA expression showed methylation of the promoter and the first exon expressed in the RAR-β2 transcript. The RAR-β2 gene from non-neoplastic cervical tissues was mostly unmethylated and expressed, but methylated alleles of the gene were found in three samples of the morphologically normal tissues adjacent to the tumors. Three cervical cancer cell lines with extremely low level of RAR-β2 mRNA expression, SiHA, HeLA and CaSki, also showed methylation of this region of the RAR-β2 gene. These findings suggest that methylation of the 5' region of RAR-β2 gene may contribute to gene silencing and that methylation of this region may be an important and early event in cervical carcinogenesis. These findings may be useful to make retinoids more effective as preventive and therapeutic agents in combination with inhibitors of DNA methylation

  12. The DNA methylation events in normal and cloned rabbit embryos

    TaoChen; Yan-LingZhang; YanJiang; Shu-ZhenLiu; HeideSchatten; Da-YuanChen; Qing-YuanSun

    2005-01-01

    To study the DNA methylation events in normal and cloned rabbit embryos, we investigated the methylation status of a satellite seqnence and the promoter region of a single-copy gene using bisulfite-sequencing technology. During normal rabbit embryo development, both sequences maintained hypermethylation status until the 8- to 16-cell stage when progressive demethylation took place. In cloned embryos, the single-copy gene promoter sequence was rapidly demethylated and preco-ciously de novo methylated, while the satellite sequence mainrained the donor-type methylation status in all examined stages. Our results indicate that unique sequences as well as satellitesequences may have aberrant methylation patterns in cloned embryos.

  13. Chromatin structure is required to block transcription of the methylated herpes simplex virus thymidine kinase gene

    Inhibition of herpes simplex virus (HSV) thymidine kinase (TK) gene transcription (pHSV-106, pML-BPV-TK4) by DNA methylation is an indirect effect, which occurs with a latency period of ∼ 8 hr microinjection of the DNA into TK- rat 2 and mouse LTK- cells. The authors have strong evidence that chromatin formation is critical for the transition of the injected DNA from methylation insensitivity to methylation sensitivity. Chromatin was reconstituted in vitro by using methylated and mock-methylated HSV TK DNA and purified chicken histone octamers. After microinjection, the methylated chromatin was always biologically inactive, as tested by autoradiography of the cells after incubation with [3H]thymidine and by RNA dot blot analysis. However, in transformed cell lines, reactivation of the methylated chromatic occurred after treatment with 5-azacytidine. Furthermore, integration of the TK chromatin into the host genome is not required to block expression of the methylated TK gene. Mouse cells that contained the pML-BPV-TK4 chromatin permanently in an episomal state also did not support TK gene expression as long as the TK DNA remained methylated

  14. Abnormal promoter methylation of multiple genes in the malignant transformed PEP2D cells induced by alpha particles exposure

    LiP; SuiJL

    2002-01-01

    The 5' promoter regions of some genes contain CpG-rich areas,known as CpG islands,Methylation of the cytosine in these dinuleotides has important regulatory effects on gene expression.The functional significance of promoter hypermethylation would play the same roles in carcinogenesis as gene mutations.The promoter methylations p14ARF,p16INK4a,MGMT,GSTP1,BUB3 and DAPK genes were analyzed with methylation specific PCR(MSP) in the transformed human bronchial epithelial cells(BEP2D) induced by α-particles.The results indicated that p14ARF gene was not methylated in BEP2D cells,but was methylated in the malignant transformed BERP35T-1 cells,and the level of its transcription was depressed remarkable in the latter.However p16INK4a gene,which shares two exons with p14ARF gene,was not methylated.MGMT gene was methylated in both BEP2D and BERP35T-1.DAPK gene was partially methylated in BEP2D cells and methylated completely in BERP35T1.GSTP1 was not methylated in BEP2D cells and was methylated partly in BERP35T-1.BUB3 gene was not methylated in BEP2D as well as BERP35T1 cells and was further proved by sequencing analysis.

  15. The Role of Methylation in Breast Cancer Susceptibility and Treatment.

    Pouliot, Marie-Christine; Labrie, Yvan; Diorio, Caroline; Durocher, Francine

    2015-09-01

    DNA methylation is a critical mechanism of epigenetic modification involved in gene expression programming, that can promote the development of several cancers, including breast cancer. The methylation of CpG islands by DNA methyltransferases is reversible and has been shown to modify the transcriptional activity of key proliferation genes or transcription factors involved in suppression or promotion of cell growth. Indeed, aberrant methylation found in gene promoters is a hallmark of cancer that could be used as non-intrusive biomarker in body fluids such as blood and plasma for early detection of breast cancer. Many biomarker genes have been evaluated for breast cancer detection. However, in the absence of a unique biomarker having the sufficient specificity and sensitivity, a panel of multiple genes should be used. Treatments targeting aberrant methylation by DNA methyltransferase inhibitors, which trigger re-expression of silenced genes, are now available and allow for better treatment efficiency. PMID:26254344

  16. Integration and bioinformatics analysis of DNA-methylated genes associated with drug resistance in ovarian cancer

    YAN, BINGBING; YIN, FUQIANG; WANG, QI; ZHANG, WEI; LI, LI

    2016-01-01

    The main obstacle to the successful treatment of ovarian cancer is the development of drug resistance to combined chemotherapy. Among all the factors associated with drug resistance, DNA methylation apparently plays a critical role. In this study, we performed an integrative analysis of the 26 DNA-methylated genes associated with drug resistance in ovarian cancer, and the genes were further evaluated by comprehensive bioinformatics analysis including gene/protein interaction, biological process enrichment and annotation. The results from the protein interaction analyses revealed that at least 20 of these 26 methylated genes are present in the protein interaction network, indicating that they interact with each other, have a correlation in function, and may participate as a whole in the regulation of ovarian cancer drug resistance. There is a direct interaction between the phosphatase and tensin homolog (PTEN) gene and at least half of the other genes, indicating that PTEN may possess core regulatory functions among these genes. Biological process enrichment and annotation demonstrated that most of these methylated genes were significantly associated with apoptosis, which is possibly an essential way for these genes to be involved in the regulation of multidrug resistance in ovarian cancer. In addition, a comprehensive analysis of clinical factors revealed that the methylation level of genes that are associated with the regulation of drug resistance in ovarian cancer was significantly correlated with the prognosis of ovarian cancer. Overall, this study preliminarily explains the potential correlation between the genes with DNA methylation and drug resistance in ovarian cancer. This finding has significance for our understanding of the regulation of resistant ovarian cancer by methylated genes, the treatment of ovarian cancer, and improvement of the prognosis of ovarian cancer. PMID:27347118

  17. Differentially methylated obligatory epialleles modulate context-dependent LAM gene expression in the honeybee Apis mellifera.

    Wedd, Laura; Kucharski, Robert; Maleszka, Ryszard

    2016-01-01

    Differential intragenic methylation in social insects has been hailed as a prime mover of environmentally driven organismal plasticity and even as evidence for genomic imprinting. However, very little experimental work has been done to test these ideas and to prove the validity of such claims. Here we analyze in detail differentially methylated obligatory epialleles of a conserved gene encoding lysosomal α-mannosidase (AmLAM) in the honeybee. We combined genotyping of progenies derived from colonies founded by single drone inseminated queens, ultra-deep allele-specific bisulfite DNA sequencing, and gene expression to reveal how sequence variants, DNA methylation, and transcription interrelate. We show that both methylated and non-methylated states of AmLAM follow Mendelian inheritance patterns and are strongly influenced by polymorphic changes in DNA. Increased methylation of a given allele correlates with higher levels of context-dependent AmLAM expression and appears to affect the transcription of an antisense long noncoding RNA. No evidence of allelic imbalance or imprinting involved in this process has been found. Our data suggest that by generating alternate methylation states that affect gene expression, sequence variants provide organisms with a high level of epigenetic flexibility that can be used to select appropriate responses in various contexts. This study represents the first effort to integrate DNA sequence variants, gene expression, and methylation in a social insect to advance our understanding of their relationships in the context of causality. PMID:26507253

  18. Methylation of the Glucocorticoid Receptor Gene Promoter in Preschoolers: Links with Internalizing Behavior Problems

    Parade, Stephanie H.; Ridout, Kathryn K.; Seifer, Ronald; Armstrong, David A.; Marsit, Carmen J.; McWilliams, Melissa A.; Tyrka, Audrey R.

    2016-01-01

    Accumulating evidence suggests that early adversity is linked to methylation of the glucocorticoid receptor (GR) gene, "NR3C1," which is a key regulator of the hypothalamic-pituitary-adrenal axis. Yet no prior work has considered the contribution of methylation of "NR3C1" to emerging behavior problems and psychopathology in…

  19. Marked methylation changes in intestinal genes during the perinatal period of preterm neonates

    Gao, Fei; Zhang, Juyong; Jiang, Pingping;

    2014-01-01

    pigs and pigs with initial evidence of NEC. In the 4 d-old formula-fed preterm pigs, four genes associated with intestinal metabolism (CYP2W1, GPR146, TOP1MT, CEND1) showed significant hyper-methylation in their promoter CGIs, and thus, down-regulated transcription. Methylation-driven down...

  20. GSH2 promoter methylation in pancreatic cancer analyzed by quantitative methylation-specific polymerase chain reaction

    Gao, Fei; HUANG, HAO-JIE; Gao, Jun; Li, Zhao-Shen; Shu-ren MA

    2015-01-01

    Tumor suppressor gene silencing via promoter hypermethylation is an important event in pancreatic cancer pathogenesis. Aberrant DNA hypermethylation events are highly tumor specific, and may provide a diagnostic tool for pancreatic cancer patients. The objective of the current study was to identify novel methylation-related genes that may potentially be used to establish novel therapeutic and diagnostic strategies against pancreatic cancer. The methylation status of the GS homeobox 2 (GSH2) g...

  1. Chromosome aberrations and transforming genes in leukemic and non-leukemic patients with a history of atomic bomb exposure

    To investigate leukemogenesis in atomic bomb (A-bomb) survivors, chromosome aberrations in bone marrow cells, and T- and B-lymphocytes from 135 healthy persons who had been exposed within 1,000 m of the hypocenter of the Hiroshima A-bomb were sequentially examined. Leukemic marrow cells from 468 patients with acute or chronic type of leukemias, including 25 acute leukemias exposed to 1 rad or more of radiation were also studied cytogenetically. Analysis of breakpoints observed in T-lymphocytes with stable types of abnormalities revealed a nonrandom distribution, and clustering in specific regions of chromosomes such as 22q1, 14q3, and 5q3. Statistical analysis revealed a higher incidence of translocations in 50 bands, including those containing cellular oncogenes such as 8q22, 8q24, and 9q34. Of these 50 bands, 20 were matched with bands specific for leukemia and cancer and 14 with constitutive fragile sites. In leukemic marrow, all 10 patients who had been exposed to radiation of more than 200 rad and then developed acute non-lymphocytic leukemia had chromosome aberrations. Their aberrations were more complex than those in patients exposed to less than 200 rad (33 patients) and in the non-exposed patients (134 patients). DNA samples extracted from bone marrow cells of 13 survivors, including 4 healthy survivors with more than 30% chromosome abnormalities in the bone marrow and 9 leukemia patients were used for in vivo selection assay of transforming genes. Tumor formation in nude mice was observed in 3 of the 4 healthy survivors and 9 leukemia patients. All of the transfectants were shown to contain Alu sequences. The transforming N-ras gene was detected for the first time in the bone marrow cells from 3 heavily exposed survivors and from 7 leukemia patients with a history of radiation exposure

  2. DDMGD: the database of text-mined associations between genes methylated in diseases from different species

    Raies, A. B.

    2014-11-14

    Gathering information about associations between methylated genes and diseases is important for diseases diagnosis and treatment decisions. Recent advancements in epigenetics research allow for large-scale discoveries of associations of genes methylated in diseases in different species. Searching manually for such information is not easy, as it is scattered across a large number of electronic publications and repositories. Therefore, we developed DDMGD database (http://www.cbrc.kaust.edu.sa/ddmgd/) to provide a comprehensive repository of information related to genes methylated in diseases that can be found through text mining. DDMGD\\'s scope is not limited to a particular group of genes, diseases or species. Using the text mining system DEMGD we developed earlier and additional post-processing, we extracted associations of genes methylated in different diseases from PubMed Central articles and PubMed abstracts. The accuracy of extracted associations is 82% as estimated on 2500 hand-curated entries. DDMGD provides a user-friendly interface facilitating retrieval of these associations ranked according to confidence scores. Submission of new associations to DDMGD is provided. A comparison analysis of DDMGD with several other databases focused on genes methylated in diseases shows that DDMGD is comprehensive and includes most of the recent information on genes methylated in diseases.

  3. PAX8 is transcribed aberrantly in cervical tumors and derived cell lines due to complex gene rearrangements.

    López-Urrutia, Eduardo; Pedroza-Torres, Abraham; Fernández-Retana, Jorge; De Leon, David Cantu; Morales-González, Fermín; Jacobo-Herrera, Nadia; Peralta-Zaragoza, Oscar; García-Mendez, Jorge; García-Castillo, Verónica; Bautista-Isidro, Osvaldo; Pérez-Plasencia, Carlos

    2016-07-01

    The transcription factor PAX8, a member of the paired box-containing gene family with an important role in embryogenesis of the kidney, thyroid gland and nervous system, has been described as a biomarker in tumors of the thyroid, parathyroid, kidney and thymus. The PAX8 gene gives rise to four isoforms, through alternative mRNA splicing, but the splicing pattern in tumors is not yet established. Cervical cancer has a positive expression of PAX8; however, there is no available data determining which PAX8 isoform or isoforms are present in cervical cancer tissues as well as in cervical carcinoma-derived cell lines. Instead of a differential pattern of splicing isoforms, we found numerous previously unreported PAX8 aberrant transcripts ranging from 378 to 542 bases and present in both cervical carcinoma-derived cell lines and tumor samples. This is the first report of PAX8 aberrant transcript production in cervical cancer. Reported PAX8 isoforms possess differential transactivation properties; therefore, besides being a helpful marker for detection of cancer, PAX8 isoforms can plausibly exert differential regulation properties during carcinogenesis. PMID:27175788

  4. The Homeobox Gene MEIS1 Is Methylated in BRAFp.V600E Mutated Colon Tumors

    Dihal, Ashwin A.; Boot, Arnoud; van Roon, Eddy H.; Schrumpf, Melanie; Fariña-Sarasqueta, Arantza; Fiocco, Marta; Zeestraten, Eliane C. M.; Kuppen, Peter J. K.; Morreau, Hans; van Wezel, Tom; Boer, Judith M.

    2013-01-01

    Development of colorectal cancer (CRC) can occur both via gene mutations in tumor suppressor genes and oncogenes, as well as via epigenetic changes, including DNA methylation. Site-specific methylation in CRC regulates expression of tumor-associated genes. Right-sided colon tumors more frequently have BRAFp.V600E mutations and have higher methylation grades when compared to left-sided malignancies. The aim of this study was to identify DNA methylation changes associated with BRAFp.V600E mutation status. We performed methylation profiling of colon tumor DNA, isolated from frozen sections enriched for epithelial cells by macro-dissection, and from paired healthy tissue. Single gene analyses comparing BRAFp.V600E with BRAF wild type revealed MEIS1 as the most significant differentially methylated gene (log2 fold change: 0.89, false discovery rate-adjusted P-value 2.8*10-9). This finding was validated by methylation-specific PCR that was concordant with the microarray data. Additionally, validation in an independent cohort (n=228) showed a significant association between BRAFp.V600E and MEIS1 methylation (OR: 13.0, 95% CI: 5.2 - 33.0, P<0.0001). MEIS1 methylation was associated with decreased MEIS1 gene expression in both patient samples and CRC cell lines. The same was true for gene expression of a truncated form of MEIS1, MEIS1D27, which misses exon 8 and has a proposed tumor suppression function. To trace the origin of MEIS1 promoter methylation, 14 colorectal tumors were flow-sorted. Four out of eight BRAFp.V600E tumor epithelial fractions (50%) showed MEIS1 promoter methylation, as well as three out of eight BRAFp.V600E stromal fractions (38%). Only one out of six BRAF wild type showed MEIS1 promoter methylation in both the epithelial tumor and stromal fractions (17%). In conclusion, BRAFp.V600E colon tumors showed significant MEIS1 promoter methylation, which was associated with decreased MEIS1 gene expression. PMID:24244575

  5. Racial Differences in DNA-Methylation of CpG Sites Within Preterm-Promoting Genes and Gene Variants.

    Salihu, H M; Das, R; Morton, L; Huang, H; Paothong, A; Wilson, R E; Aliyu, M H; Salemi, J L; Marty, P J

    2016-08-01

    Objective To evaluate the role DNA methylation may play in genes associated with preterm birth for higher rates of preterm births in African-American women. Methods Fetal cord blood samples from births collected at delivery and maternal demographic and medical information were used in a cross-sectional study to examine fetal DNA methylation of genes implicated in preterm birth among black and non-black infants. Allele-specific DNA methylation analysis was performed using a methylation bead array. Targeted maximum likelihood estimation was applied to examine the relationship between race and fetal DNA methylation of candidate preterm birth genes. Receiver-operating characteristic analyses were then conducted to validate the CpG site methylation marker within the two racial groups. Bootstrapping, a method of validation and replication, was employed. Results 42 CpG sites were screened within 20 candidate gene variants reported consistently in the literature as being associated with preterm birth. Of these, three CpG sites on TNFAIP8 and PON1 genes (corresponding to: cg23917399; cg07086380; and cg07404485, respectively) were significantly differentially methylated between black and non-black individuals. The three CpG sites showed lower methylation status among infants of black women. Bootstrapping validated and replicated results. Conclusion for Practice Our study identified significant differences in levels of methylation on specific genes between black and non-black individuals. Understanding the genetic/epigenetic mechanisms that lead to preterm birth may lead to enhanced prevention strategies to reduce morbidity and mortality by eventually providing a means to identify individuals with a genetic predisposition to preterm labor. PMID:27000849

  6. The mom gene of bacteriophage Mu: the mechanism of methylation-dependent expression.

    Seiler, A.; Blöcker, H; Frank, R.; Kahmann, R

    1986-01-01

    Transcription of the DNA modification gene (mom) of bacteriophage Mu requires methylation of three GATC sites upstream of the mom promoter by the Escherichia coli deoxyadenosine methylation function (Dam). The three sites map within a 40-bp segment termed region I. Small deletions, inversions, duplications and specific point mutations have been introduced in region I. Their effect on mom expression has been studied in dam+ and dam strains. Dam-dependent expression of the mom gene requires a s...

  7. DNA Methylation Impacts Gene Expression and Ensures Hypoxic Survival of Mycobacterium tuberculosis

    Shell, Scarlet S.; Prestwich, Erin G.; Seung-Hun Baek; Shah, Rupal R.; Sassetti, Christopher M.; Dedon, Peter C.; Fortune, Sarah M.

    2012-01-01

    DNA methylation regulates gene expression in many organisms. In eukaryotes, DNA methylation is associated with gene repression, while it exerts both activating and repressive effects in the Proteobacteria through largely locus-specific mechanisms. Here, we identify a critical DNA methyltransferase in M. tuberculosis, which we term MamA. MamA creates N[superscript 6]-methyladenine in a six base pair recognition sequence present in approximately 2,000 copies on each strand of the genome. Loss o...

  8. DNA Methylation Impacts Gene Expression and Ensures Hypoxic Survival of Mycobacterium tuberculosis

    Shell, Scarlet S.; Prestwich, Erin G.; Baek, Seung-Hun; Shah, Rupal R.; Sassetti, Christopher M.; Dedon, Peter C.; Fortune, Sarah M.

    2013-01-01

    DNA methylation regulates gene expression in many organisms. In eukaryotes, DNA methylation is associated with gene repression, while it exerts both activating and repressive effects in the Proteobacteria through largely locus-specific mechanisms. Here, we identify a critical DNA methyltransferase in M. tuberculosis, which we term MamA. MamA creates N6-methyladenine in a six base pair recognition sequence present in approximately 2,000 copies on each strand of the genome. Loss of MamA reduces...

  9. DELETION AND 5'CPG ISLAND METHYLATION OF p15 GENE IN BRAIN GLIOMA

    2000-01-01

    Objective: To investigate the abnormality of p15 gene in brain glioma and the correlation of it with occurrence or malignant progression of brain glioma. Methods: Deletion and 5'CPG island methylation of p15 gene were detected by the methods of PCR and PCR-based methylation in 56 cases of brain glioma. Results: Out of 43 cases of high grade glioma, 14 cases were found to have homozygous deletion of p15E1, while none of the 13 cases of low grade glioma was found to have deletion of p15E1 (P<0.05). Methylation of 5'CPG Island of p15 gene was found only in four cases of glioma. Conclusion: Abnormality of p15 gene may involved in the occurrence and malignant progression of brain glioma. Homozygous deletion of gene is the major mechanism of inactivation for p15 gene in brain glioma.

  10. Global hypomethylation and promoter methylation in small intestinal neuroendocrine tumors

    Fotouhi, Omid; Adel Fahmideh, Maral; Kjellman, Magnus; Sulaiman, Luqman; Höög, Anders; Zedenius, Jan; Hashemi, Jamileh; Larsson, Catharina

    2014-01-01

    Aberrant DNA methylation is a feature of human cancer affecting gene expression and tumor phenotype. Here, we quantified promoter methylation of candidate genes and global methylation in 44 small intestinal-neuroendocrine tumors (SI-NETs) from 33 patients by pyrosequencing. Findings were compared with gene expression, patient outcome and known tumor copy number alterations. Promoter methylation was observed for WIF1, RASSF1A, CTNNB1, CXCL14, NKX2–3, P16, LAMA1, and CDH1. By contrast APC, CDH3...

  11. Body Mass Index is Associated with Gene Methylation in Estrogen Receptor-Positive Breast Tumors

    Hair, Brionna Y.; Troester, Melissa A.; Edmiston, Sharon N.; Parrish, Eloise A.; Robinson, Whitney R.; Wu, Michael C.; Olshan, Andrew F.; Swift-Scanlan, Theresa; Conway, Kathleen

    2015-01-01

    Background Although obesity is associated with breast cancer incidence and prognosis, the underlying mechanisms are poorly understood. Identification of obesity-associated epigenetic changes in breast tissue may advance mechanistic understanding of breast cancer initiation and progression. The goal of this study, therefore, was to investigate associations between obesity and gene methylation in breast tumors. Methods Using the Illumina GoldenGate Cancer I Panel, we estimated the association between body mass index (BMI) and gene methylation in 345 breast tumor samples from Phase I of the Carolina Breast Cancer Study, a population based case-control study. Multivariable linear regression was used to identify sites that were differentially methylated by BMI. Stratification by tumor estrogen receptor status was also conducted. Results In the majority of the 935 probes analyzed (87%), the average beta value increased with obesity (BMI ≥ 30). Obesity was significantly associated with differential methylation (false discovery rate q-value < 0.05) in just 2 gene loci in breast tumor tissue overall and in 21 loci among estrogen receptor (ER)-positive tumors. Obesity was associated with methylation of genes that function in immune response, cell growth, and DNA repair. Conclusions Obesity is associated with altered methylation overall, and with hypermethylation among ER-positive tumors in particular, suggesting that obesity may influence the methylation of genes with known relevance to cancer. Some of these differences in methylation by obese status may influences levels of gene expression within breast cells. Impact If our results are validated, obesity-associated methylation sites could serve as targets for prevention and treatment research. PMID:25583948

  12. Chromosomal aberrations in environmentally exposed population in relation to metabolic and DNA repair genes polymorphisms

    Šrám, Radim; Beskid, Olena; Binková, Blanka; Chvátalová, Irena; Lněničková, Zdena; Milcová, Alena; Solanský, I.; Tulupová, Elena; Bavorová, H.; Ocadlíková, D.; Farmer, P. B.

    2007-01-01

    Roč. 620, - (2007), s. 22-33. ISSN 0027-5107 R&D Projects: GA MŽP SI/340/2/00; GA MŽP SL/740/5/03; GA MŽP SL/5/160/05 Grant ostatní: EU(GB) 2000-00091 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK Keywords : chromosomal aberrations * cytogenetic analysis * carcinogenic PAHs Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

  13. MicroRNA Methylation in Colorectal Cancer.

    Kaur, Sippy; Lotsari-Salomaa, Johanna E; Seppänen-Kaijansinkko, Riitta; Peltomäki, Päivi

    2016-01-01

    Epigenetic alterations such as DNA methylation, histone modifications and non-coding RNA (including microRNA) associated gene silencing have been identified as a major characteristic in human cancers. These alterations may occur more frequently than genetic mutations and play a key role in silencing tumor suppressor genes or activating oncogenes, thereby affecting multiple cellular processes. In recent years, studies have shown that microRNAs, that act as posttranscriptional regulators of gene expression are frequently deregulated in colorectal cancer (CRC), via aberrant DNA methylation. Over the past decade, technological advances have revolutionized the field of epigenetics and have led to the identification of numerous epigenetically dysregulated miRNAs in CRC, which are regulated by CpG island hypermethylation and DNA hypomethylation. In addition, aberrant DNA methylation of miRNA genes holds a great promise in several clinical applications such as biomarkers for early screening, prognosis, and therapeutic applications in CRC. PMID:27573897

  14. Differential DNA Methylation of MicroRNA Genes in Temporal Cortex from Alzheimer's Disease Individuals

    Villela, Darine; Ramalho, Rodrigo F.; Silva, Aderbal R. T.; Brentani, Helena; Suemoto, Claudia K.; Pasqualucci, Carlos Augusto; Grinberg, Lea T.; Krepischi, Ana C. V.; Rosenberg, Carla

    2016-01-01

    This study investigated for the first time the genomewide DNA methylation changes of noncoding RNA genes in the temporal cortex samples from individuals with Alzheimer's disease (AD). The methylome of 10 AD individuals and 10 age-matched controls were obtained using Illumina 450 K methylation array. A total of 2,095 among the 15,258 interrogated noncoding RNA CpG sites presented differential methylation, 161 of which were associated with miRNA genes. In particular, 10 miRNA CpG sites that wer...

  15. Aberrations of ERBB2 and TOP2A Genes in Breast Cancer

    Nielsen, Kirsten Vang; Müller, Sven; Møller, Susanne;

    2009-01-01

    spreads from cell lines showed that simultaneous amplification is not a simple co-amplification of a whole amplicon containing both genes. Most gene signals are translocated to abnormal marker chromosomes. ERBB2 genes but not TOP2A genes are present in tandem amplicons, leading to a higher ERBB2 ratio...... also observed (5%) but only in tumors with simultaneous TOP2A deletion. The average gene/reference ratio was significantly different: 5.0 for TOP2A but 7.2 for ERBB2 in the amplified tumors (P<0.01). Amplification of the two genes may be caused by different mechanisms, leading to higher level of...

  16. Transcriptional activity of acetylcholinesterase gene is regulated by DNA methylation during C2C12 myogenesis.

    Lau, Kei M; Gong, Amy G W; Xu, Miranda L; Lam, Candy T W; Zhang, Laura M L; Bi, Cathy W C; Cui, D; Cheng, Anthony W M; Dong, Tina T X; Tsim, Karl W K; Lin, Huangquan

    2016-07-01

    The expression of acetylcholinesterase (AChE), an enzyme hydrolyzes neurotransmitter acetylcholine at vertebrate neuromuscular junction, is regulated during myogenesis, indicating the significance of muscle intrinsic factors in controlling the enzyme expression. DNA methylation is essential for temporal control of myogenic gene expression during myogenesis; however, its role in AChE regulation is not known. The promoter of vertebrate ACHE gene carries highly conserved CG-rich regions, implying its likeliness to be methylated for epigenetic regulation. A DNA methyltransferase inhibitor, 5-azacytidine (5-Aza), was applied onto C2C12 cells throughout the myotube formation. When DNA methylation was inhibited, the promoter activity, transcript expression and enzymatic activity of AChE were markedly increased after day 3 of differentiation, which indicated the putative role of DNA methylation. By bisulfite pyrosequencing, the overall methylation rate was found to peak at day 3 during C2C12 cell differentiation; a SP1 site located at -1826bp upstream of mouse ACHE gene was revealed to be heavily methylated. The involvement of transcriptional factor SP1 in epigenetic regulation of AChE was illustrated here: (i) the SP1-driven transcriptional activity was increased in 5-Aza-treated C2C12 culture; (ii) the binding of SP1 onto the SP1 site of ACHE gene was fully blocked by the DNA methylation; and (iii) the sequence flanking SP1 sites of ACHE gene was precipitated by chromatin immuno-precipitation assay. The findings suggested the role of DNA methylation on AChE transcriptional regulation and provided insight in elucidating the DNA methylation-mediated regulatory mechanism on AChE expression during muscle differentiation. PMID:27021952

  17. Quantitative methylation-specific PCR - optimization and application

    Pharo, Heidi Dietrichson

    2014-01-01

    Aberrant DNA methylation is one of the most common alterations in cancer, and a vast diversity of methods for its investigation exists. Quantitative methylation-specific PCR (qMSP) is frequently used to estimate the amounts of methylation at specific loci, such as gene promoters. However, diverging qMSP results are being reported in the literature, underscoring the need for standardization of the individual steps of the protocol. In this study we aimed at identifying the most likely sources o...

  18. The Methylation of SOCS-1 Gene in Adult Acute Myeloid Leukemia%成人急性髓性白血病SOCS-1基因及其甲基化的研究

    庄衍; 程毅敏; 汪雷; 窦红菊; 朱琦; 胡钧培

    2011-01-01

    Objective: To investigate the role of SOCS-1 (Suppressor of Cytokine Signalling-1) in tumorigenesis of adult acute myeloid leukemia (AMDby detecting the methylation state and expression of SOCS-1 gene. Methods: A total of 24 patients with AML, 10 healthy volunteers and 4 cell lines (Jurkat, Raji, U 937, NALM 17) were chosen. The methylation state of SOCS-1 in samples and cell lines were detected by using methylation-specific polymerase chain reation (MSP), and the expression of SOCS-1 was detected by using Real-time PCR. Results: The aberrant methylation of SOCS-1 was 62.5 % (15/24 )in primary patients with AML. In contrast, there was no aberrant methylation of SOCS-1 gene in normal samples (P<0.05). The expression of SOCS-1 in AML patients with aberrant methylation of SOCS-1 gene was lower than that in AML patients without aberrant methylation of SOCS-1 gene (P<0.05). There was no relation between the methylation of SOCS-1 gene and the clinicopathological data (such as sex, age and tumor stage). Conclusion: The methylation of SOCS-1 gene in AML was higher than that in control group significantly (P<0.05), and aberrant methylation strongly correlates with reduced expression. SOCS-1 gene may play an important role in tumorigenesis of AML.%目的:通过检测成人急性髓性白血病中SOCS-1基因表达水平及其甲基化水平,研究其在白血病发病中的作用.方法:运用甲基化特异性PCR(Methylation specific PCR,MSP)方法,对24例急性髓性白血病患者和4株白血病细胞株(Jurkat、Raji、U 937、NALM 17),进行SOCS-1基因甲基化水平的研究;同时运用Real-time PCR法定量分析SOCS-1基因表达水平.以10例健康人为正常对照组.结果:24例成人急性髓性白血病患者中,15例有SOCS-1基因甲基化(62.5%),而正常对照组无SOCS-1基因甲基化(0%),二者有显著差异( P<0.05);SOCS-1基因甲基化组与无SOCS-1基因甲基化组相比较,其SOCS-1基因相对表达量明显减少(P口0.05);与患

  19. DNA Methylation in Thyroid Tumorigenesis

    Thyroid cancer is the most common endocrine cancer with 1,690 deaths each year. There are four main types of which the papillary and follicular types together account for >90% followed by medullary cancers with 3% to 5% and anaplastic carcinomas making up <3%. Epigenetic events of DNA hypermethylation are emerging as promising molecular targets for cancer detection. Our immediate and long term goal is to identify DNA methylation markers for early detection of thyroid cancer. This pilot study comprised of 21 patients to include 11 papillary thyroid cancers (PTC), 2 follicular thyroid cancers (FTC), 5 normal thyroid cases, and 3 hyperthyroid cases. Aberrant promoter methylation was examined in 24 tumor suppressor genes using the methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) assay and in the NIS gene using methylation-specific PCR (MSP). The frequently methylated genes were CASP8 (17/21), RASSF1 (16/21) and NIS (9/21). In the normal samples, CASP8, RASSF1 and NIS were methylated in 5/5, 4/5 and 1/5 respectively. In the hyperthyroid samples, CASP8, RASSF1 and NIS were methylated in 3/3, 2/3 and 1/3 respectively. In the thyroid cancers, CASP8, RASSF1, and NIS were methylated in 9/13, 10/13, and 7/13 respectively. CASP8, RASSF1 and NIS were also methylated in concurrently present normal thyroid tissue in 3/11, 4/11 and 3/11 matched thyroid cancer cases (matched for presence of both normal thyroid tissue and thyroid cancer), respectively. Our data suggests that aberrant methylation of CASP8, RASSF1, and NIS maybe an early change in thyroid tumorigenesis regardless of cell type

  20. Improved antisense oligonucleotide design to suppress aberrant SMN2 gene transcript processing: towards a treatment for spinal muscular atrophy.

    Chalermchai Mitrpant

    Full Text Available Spinal muscular atrophy (SMA is caused by loss of the Survival Motor Neuron 1 (SMN1 gene, resulting in reduced SMN protein. Humans possess the additional SMN2 gene (or genes that does produce low level of full length SMN, but cannot adequately compensate for loss of SMN1 due to aberrant splicing. The majority of SMN2 gene transcripts lack exon 7 and the resultant SMNΔ7 mRNA is translated into an unstable and non-functional protein. Splice intervention therapies to promote exon 7 retention and increase amounts of full-length SMN2 transcript offer great potential as a treatment for SMA patients. Several splice silencing motifs in SMN2 have been identified as potential targets for antisense oligonucleotide mediated splice modification. A strong splice silencer is located downstream of exon 7 in SMN2 intron 7. Antisense oligonucleotides targeting this motif promoted SMN2 exon 7 retention in the mature SMN2 transcripts, with increased SMN expression detected in SMA fibroblasts. We report here systematic optimisation of phosphorodiamidate morpholino oligonucleotides (PMO that promote exon 7 retention to levels that rescued the phenotype in a severe mouse model of SMA after intracerebroventricular delivery. Furthermore, the PMO gives the longest survival reported to date after a single dosing by ICV.

  1. Aberrant splicing and missense mutations cause steroid 21-hydroxylase [P-450(C21)] deficiency in humans: Possible gene conversion products

    Four steroid 21-hydroxylase B [P-450(C21)B] genes (designated P.7, P.10-1, P.10-2, and P.3) from three P-450(C21)-deficient patients were isolated to analyze their structures and functions. Several base changes were observed in the sequences of the four P-450(C21)B genes as compared to that of the functional B gene. Many of these base changes were identical to those of the P-450(C21)A pseudogene. The three DNAs (P.10-1, P.10.2, and P.3) produced no P-450(C21) activity in a functional assay for P-450(C21) by the COS cell expression system, while the P.7 DNA expressed the activity. The P.10-1 and P.10-2 DNAs were shown to have a point mutation in the second intron, causing aberrant splicing. The P.3 DNA carried three clustered missense mutations in the sixty exon, which impaired P-450(C21) activity. All these critical mutations could be seen in the corresponding site of the P-450(C21)A pseudogene. These data strongly suggest the involvement of gene conversion in this genetic disease

  2. Differential DNA methylation patterns of homeobox genes in proximal and distal colon epithelial cells.

    Barnicle, Alan; Seoighe, Cathal; Golden, Aaron; Greally, John M; Egan, Laurence J

    2016-04-01

    Region and cell-type specific differences in the molecular make up of colon epithelial cells have been reported. Those differences may underlie the region-specific characteristics of common colon epithelial diseases such as colorectal cancer and inflammatory bowel disease. DNA methylation is a cell-type specific epigenetic mark, essential for transcriptional regulation, silencing of repetitive DNA and genomic imprinting. Little is known about any region-specific variations in methylation patterns in human colon epithelial cells. Using purified epithelial cells and whole biopsies (n= 19) from human subjects, we generated epigenome-wide DNA methylation data (using the HELP-tagging assay), comparing the methylation signatures of the proximal and distal colon. We identified a total of 125 differentially methylated sites (DMS) mapping to transcription start sites of protein-coding genes, most notably several members of the homeobox (HOX) family of genes. Patterns of differential methylation were validated with MassArray EpiTYPER. We also examined DNA methylation in whole biopsies, applying a computational technique to deconvolve variation in methylation within cell types and variation in cell-type composition across biopsies. Including inferred epithelial proportions as a covariate in differential methylation analysis applied to the whole biopsies resulted in greater overlap with the results obtained from purified epithelial cells compared with when the covariate was not included. Results obtained from both approaches highlight region-specific methylation patterns ofHOXgenes in colonic epithelium. Regional variation in methylation patterns has implications for the study of diseases that exhibit regional expression patterns in the human colon, such as inflammatory bowel disease and colorectal cancer. PMID:26812987

  3. Methylation analysis of multiple genes in blood DNA of Alzheimer's disease and healthy individuals.

    Tannorella, Pierpaola; Stoccoro, Andrea; Tognoni, Gloria; Petrozzi, Lucia; Salluzzo, Maria Grazia; Ragalmuto, Alda; Siciliano, Gabriele; Haslberger, Alexander; Bosco, Paolo; Bonuccelli, Ubaldo; Migliore, Lucia; Coppedè, Fabio

    2015-07-23

    We collected blood DNA from 120 late-onset Alzheimer's disease (AD) patients and 115 healthy matched controls and analysed the methylation levels of genes involved in amyloid-beta peptide production (PSEN1 and BACE1), in DNA methylation (DNMT1, DNMT3A and DNMT3B), and in one-carbon metabolism (MTHFR), searching for correlation with age and gender, with biomarkers of one-carbon metabolism (plasma homocysteine, and serum folate and vitamin B12 levels), and with disease status (being healthy or having AD). We also evaluated the contribution of the APOE ϵ4 allele, the major late-onset AD genetic risk factor, to the studied gene methylation levels. All the genes showed low mean methylation levels (<5%) in both AD and control DNA, no difference between groups, and no correlation with the studied biomarkers, except for MTHFR that showed methylation levels ranging from 5% to 75%, and correlation with circulating biomarkers of one-carbon metabolism. However, mean MTHFR methylation levels were similar between groups (31.1% in AD and 30.7% in controls, P=0.58). Overall, present data suggest that none of the studied regions is differently methylated in blood DNA between AD and control subjects. PMID:26079324

  4. Heritable genome-wide variation of gene expression and promoter methylation between wild and domesticated chickens

    Nätt Daniel

    2012-02-01

    Full Text Available Abstract Background Variations in gene expression, mediated by epigenetic mechanisms, may cause broad phenotypic effects in animals. However, it has been debated to what extent expression variation and epigenetic modifications, such as patterns of DNA methylation, are transferred across generations, and therefore it is uncertain what role epigenetic variation may play in adaptation. Results In Red Junglefowl, ancestor of domestic chickens, gene expression and methylation profiles in thalamus/hypothalamus differed substantially from that of a domesticated egg laying breed. Expression as well as methylation differences were largely maintained in the offspring, demonstrating reliable inheritance of epigenetic variation. Some of the inherited methylation differences were tissue-specific, and the differential methylation at specific loci were little changed after eight generations of intercrossing between Red Junglefowl and domesticated laying hens. There was an over-representation of differentially expressed and methylated genes in selective sweep regions associated with chicken domestication. Conclusions Our results show that epigenetic variation is inherited in chickens, and we suggest that selection of favourable epigenomes, either by selection of genotypes affecting epigenetic states, or by selection of methylation states which are inherited independently of sequence differences, may have been an important aspect of chicken domestication.

  5. Altered DNA methylation in PAH deficient phenylketonuria.

    Dobrowolski, Steven F; Lyons-Weiler, James; Spridik, Kayla; Biery, Amy; Breck, Jane; Vockley, Jerry; Yatsenko, Svetlana; Sultana, Tamanna

    2015-01-01

    While phenylalanine (PHE) is the toxic insult in phenylketonuria (PKU), mechanisms underlying PHE toxicity remain ill-defined. Altered DNA methylation in response to toxic exposures is well-recognized. DNA methylation patterns were assessed in blood and brain from PKU patients to determine if PHE toxicity impacts methylation. Methylome assessment, utilizing methylated DNA immunoprecipitation and paired-end sequencing, was performed in DNA obtained from brain tissue of classical PKU patients, leukocytes from poorly controlled PKU patients, leukocytes from well controlled PKU patients, and appropriate control tissues. In PKU brain tissue, expression analysis determined the impact of methylation on gene function. Differential methylation was observed in brain tissue of PKU patients and expression studies identified downstream impact on gene expression. Altered patterns of methylation were observed in leukocytes of well controlled and poorly controlled patients with more extensive methylation in patients with high PHE exposure. Differential methylation of noncoding RNA genes was extensive in patients with high PHE exposure but minimal in well controlled patients. Methylome repatterning leading to altered gene expression was present in brain tissue of PKU patients, suggesting a role in neuropathology. Aberrant methylation is observed in leukocytes of PKU patients and is influenced by PHE exposure. DNA methylation may provide a biomarker relating to historic PHE exposure. PMID:25990862

  6. Methylation Status of Vitamin D Receptor Gene Promoter in Benign and Malignant Adrenal Tumors

    Catia Pilon; Andrea Rebellato; Riccardo Urbanet; Vincenza Guzzardo; Rocco Cappellesso; Hironobu Sasano; Ambrogio Fassina; Francesco Fallo

    2015-01-01

    We previously showed a decreased expression of vitamin D receptor (VDR) mRNA/protein in a small group of adrenocortical carcinoma (ACC) tissues, suggesting the loss of a protective role of VDR against malignant cell growth in this cancer type. Downregulation of VDR gene expression may result from epigenetics events, that is, methylation of cytosine nucleotide of CpG islands in VDR gene promoter. We analyzed methylation of CpG sites in the VDR gene promoter in normal adrenals and adrenocortica...

  7. Dopamine signaling leads to loss of Polycomb repression and aberrant gene activation in experimental parkinsonism

    Södersten, Erik; Feyder, Michael; Lerdrup, Mads;

    2014-01-01

    Polycomb group (PcG) proteins bind to and repress genes in embryonic stem cells through lineage commitment to the terminal differentiated state. PcG repressed genes are commonly characterized by the presence of the epigenetic histone mark H3K27me3, catalyzed by the Polycomb repressive complex 2. ...

  8. Chromosomal aberration

    Chromosomal aberrations are classified into two types, chromosome-type and chromatid-type. Chromosom-type aberrations include terminal deletion, dicentric, ring and interstitial deletion, and chromatid-type aberrations include achromatic lesion, chromatid deletion, isochromatid deletion and chromatid exchange. Clastogens which induce chromosomal aberration are divided into ''S-dependent'' agents and ''S-independent''. It might mean whether they can induce double strand breaks independent of the S phase or not. Double strand breaks may be the ultimate lesions to induce chromosomal aberrations. Caffeine added even in the G2 phase appeared to modify the frequency of chromatid aberrations induced by X-rays and mitomycin C. Those might suggest that the G2 phase involves in the chromatid aberration formation. The double strand breaks might be repaired by ''G2 repair system'', the error of which might yield breakage types of chromatid aberrations and the by-pass of which might yield chromatid exchanges. Chromosome-type aberrations might be formed in the G1 phase. (author)

  9. NGX6 gene mediated by promoter methylation as a potential molecular marker in colorectal cancer

    Shen Shourong

    2010-04-01

    Full Text Available Abstract Background Nasopharyngeal carcinoma associated gene 6 (NGX6 is down-regulated in most colon cancer cell lines and tumor tissues when compared with their normal tissue samples. As a novel suppress tumor gene, it could inhibit colon cancer cell growth and cell cycle progression. However, little is known about the transcriptional mechanisms controlling NGX6 gene expression. Recent findings suggest that epigenetic inactivation of multiple tumor suppressor genes plays an important role in the tumorigenesis of colorectal carcinoma (CRC. In this study, we explored the role of DNA methylation in regulation of NGX6 transcription. Methods In the present study, we cloned the NGX6 promoter with characteristics of a CpG island by luciferase reporter assay. Then, the CpG methylation status around the NGX6 promoter region in colon cancer cell lines and colorectal tumor tissues was examined by methylation-specific PCR and bisulfite DNA sequencing. Finally, 5-Aza-2'-deoxycytidine (5-Aza-dC treatment was used to confirm the correlation between NGX6 promoter methylation and its gene inactivation. Results The sequence spanning positions -157 to +276 was identified as the NGX6 promoter, in which no canonical TATA boxes were found, while two CAAT boxes and GC boxes were discovered. Methylation status was observed more frequently in 40 colorectal cancer samples than in 40 adjacent normal mucosa samples (18/40 versus 7/40; P Conclusions Down-regulation of NGX6 gene is related to the promoter methylation. DNA methylation of NGX6 promoter might be a potential molecular marker for diagnosis or prognosis, or serve as a therapeutic target.

  10. Methylation of WTH3, a possible drug resistant gene, inhibits p53 regulated expression

    Previous results showed that over-expression of the WTH3 gene in MDR cells reduced MDR1 gene expression and converted their resistance to sensitivity to various anticancer drugs. In addition, the WTH3 gene promoter was hypermethylated in the MCF7/AdrR cell line and primary drug resistant breast cancer epithelial cells. WTH3 was also found to be directly targeted and up regulated by the p53 gene. Furthermore, over expression of the WTH3 gene promoted the apoptotic phenotype in various host cells. To further confirm WTH3's drug resistant related characteristics, we recently employed the small hairpin RNA (shRNA) strategy to knockdown its expression in HEK293 cells. In addition, since the WTH3 promoter's p53-binding site was located in a CpG island that was targeted by methylation, we were interested in testing the possible effect this epigenetic modification had on the p53 transcription factor relative to WTH3 expression. To do so, the in vitro methylation method was utilized to examine the p53 transgene's influence on either the methylated or non-methylated WTH3 promoter. The results generated from the gene knockdown strategy showed that reduction of WTH3 expression increased MDR1 expression and elevated resistance to Doxorubicin as compared to the original control cells. Data produced from the methylation studies demonstrated that DNA methylation adversely affected the positive impact of p53 on WTH3 promoter activity. Taken together, our studies provided further evidence that WTH3 played an important role in MDR development and revealed one of its transcription regulatory mechanisms, DNA methylation, which antagonized p53's positive impact on WTH3 expression

  11. DNMT1-interacting RNAs block gene-specific DNA methylation

    Di Ruscio, A.; Ebralidze, A.; Benoukraf, T.; Amabile, G.; Goff, L.A.; Terragni, J.; Figueroa, M.E.; Pontes, L.L.D.; Alberich-Jorda, Meritxell; Zhang, P.; Wu, M.C.; D´Alo, F.; Melnick, A.; Leone, G.; Ebralidze, K.K.; Pradhan, S.; Rinn, J.L.; Tenen, D.G.

    2013-01-01

    Roč. 503, č. 7476 (2013), s. 371-376. ISSN 0028-0836 R&D Projects: GA MŠk LK21307 Institutional support: RVO:68378050 Keywords : DNA methylation * non-coding RNA * DNMT1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 42.351, year: 2013

  12. Quantitative global and gene-specific promoter methylation in relation to biological properties of neuroblastomas

    Kiss Nimrod B

    2012-09-01

    Full Text Available Abstract Background In this study we aimed to quantify tumor suppressor gene (TSG promoter methylation densities levels in primary neuroblastoma tumors and cell lines. A subset of these TSGs is associated with a CpG island methylator phenotype (CIMP in other tumor types. Methods The study panel consisted of 38 primary tumors, 7 established cell lines and 4 healthy references. Promoter methylation was determined by bisulphate Pyrosequencing for 14 TSGs; and LINE-1 repeat element methylation was used as an indicator of global methylation levels. Results Overall mean TSG Z-scores were significantly increased in cases with adverse outcome, but were unrelated to global LINE-1 methylation. CIMP with hypermethylation of three or more gene promoters was observed in 6/38 tumors and 7/7 cell lines. Hypermethylation of one or more TSG (comprising TSGs BLU, CASP8, DCR2, CDH1, RASSF1A and RASSF2 was evident in 30/38 tumors. By contrast only very low levels of promoter methylation were recorded for APC, DAPK1, NORE1A, P14, P16, TP73, PTEN and RARB. Similar involvements of methylation instability were revealed between cell line models and neuroblastoma tumors. Separate analysis of two proposed CASP8 regulatory regions revealed frequent and significant involvement of CpG sites between exon 4 and 5, but modest involvement of the exon 1 region. Conclusions/significance The results highlight the involvement of TSG methylation instability in neuroblastoma tumors and cell lines using quantitative methods, support the use of DNA methylation analyses as a prognostic tool for this tumor type, and underscore the relevance of developing demethylating therapies for its treatment.

  13. NGX6 gene mediated by promoter methylation as a potential molecular marker in colorectal cancer

    Nasopharyngeal carcinoma associated gene 6 (NGX6) is down-regulated in most colon cancer cell lines and tumor tissues when compared with their normal tissue samples. As a novel suppress tumor gene, it could inhibit colon cancer cell growth and cell cycle progression. However, little is known about the transcriptional mechanisms controlling NGX6 gene expression. Recent findings suggest that epigenetic inactivation of multiple tumor suppressor genes plays an important role in the tumorigenesis of colorectal carcinoma (CRC). In this study, we explored the role of DNA methylation in regulation of NGX6 transcription. In the present study, we cloned the NGX6 promoter with characteristics of a CpG island by luciferase reporter assay. Then, the CpG methylation status around the NGX6 promoter region in colon cancer cell lines and colorectal tumor tissues was examined by methylation-specific PCR and bisulfite DNA sequencing. Finally, 5-Aza-2'-deoxycytidine (5-Aza-dC) treatment was used to confirm the correlation between NGX6 promoter methylation and its gene inactivation. The sequence spanning positions -157 to +276 was identified as the NGX6 promoter, in which no canonical TATA boxes were found, while two CAAT boxes and GC boxes were discovered. Methylation status was observed more frequently in 40 colorectal cancer samples than in 40 adjacent normal mucosa samples (18/40 versus 7/40; P < 0.05). An analysis correlating gene methylation status with clinicopathological cancer features revealed that dense methylation of the NGX6 promoter was associated with colorectal cancer patients age (P < 0.05). Moreover, a trend was shown toward metastasis status and primary site in colorectal carcinomas with NGX6 promoter methylation (p = 0.056 and P = 0.067, respectively). In addition, 5-Aza-dC could induce NGX6 mRNA expression and NGX6 promoter demethylation in HT-29 cells. Down-regulation of NGX6 gene is related to the promoter methylation. DNA methylation of NGX6 promoter might

  14. Pluripotency Genes and Their Functions in the Normal and Aberrant Breast and Brain

    Tracy Seymour

    2015-11-01

    Full Text Available Pluripotent stem cells (PSCs attracted considerable interest with the successful isolation of embryonic stem cells (ESCs from the inner cell mass of murine, primate and human embryos. Whilst it was initially thought that the only PSCs were ESCs, in more recent years cells with similar properties have been isolated from organs of the adult, including the breast and brain. Adult PSCs in these organs have been suggested to be remnants of embryonic development that facilitate normal tissue homeostasis during repair and regeneration. They share certain characteristics with ESCs, such as an inherent capacity to self-renew and differentiate into cells of the three germ layers, properties that are regulated by master pluripotency transcription factors (TFs OCT4 (octamer-binding transcription factor 4, SOX2 (sex determining region Y-box 2, and homeobox protein NANOG. Aberrant expression of these TFs can be oncogenic resulting in heterogeneous tumours fueled by cancer stem cells (CSC, which are resistant to conventional treatments and are associated with tumour recurrence post-treatment. Further to enriching our understanding of the role of pluripotency TFs in normal tissue function, research now aims to develop optimized isolation and propagation methods for normal adult PSCs and CSCs for the purposes of regenerative medicine, developmental biology, and disease modeling aimed at targeted personalised cancer therapies.

  15. Splicing aberrations caused by constitutional RB1 gene mutations in retinoblastoma

    Vidya Latha Parsam; Mohammed Javed Ali; Santosh G Honavar; Geeta K Vemuganti; Chitra Kannabiran

    2011-06-01

    Analysis of RB1 mRNA from blood leukocytes of patients with retinoblastoma identified the effects of mutations involving consensus splice site, exonic substitution and whole-exon deletions identified in genomic DNA of these patients. In addition, this study identified mutations in cases in which no mutations were detectable in the genomic DNA. One proband had mutation at the canonical splice site at +5 position of IVS22, and analysis of the transcripts in this family revealed skipping of exon 22 in three members of this family. In one proband, a missense substitution of c.652T > G (g.56897T > G; Leu218Val) in exon 7 led to splicing aberrations involving deletions of exons 7 and 8, suggesting the formation of a cryptic splice site. In two probands with no detectable changes in the genomic DNA upon screening of RB1 exons and flanking intronic sequences, transcripts were found to have deletions of exon 6 in one, and exons 21 and 22 in another family. In two probands, RNA analysis confirmed genomic deletions involving one or more exons. This study reveals novel effects of RB1 mutations on splicing and suggests the utility of RNA analysis as an adjunct to mutational screening of genomic DNA in retinoblastoma.

  16. DNA Methylation in exon 1 of CDKN2A gene in formalin-fixed, paraffin-embedded colon cancer samples

    Hossein Faramarzi; Elham Moslemi; Amir Izadi

    2015-01-01

    Background: The molecular studies indicate some of the genes in the promoter region itself, will undergo methylation. Methylation of CpG islands in the promoter region of that cause silence or reduced expression of genes involved in cell growth pathways, which are colorectal cancer causing agents. Detection of methylation status can be used as a marker for cancer diagnosis and prediction of disease. CDKN2A tumor suppressor gene encodes a protein, which inhibit CDK 4/6 and loss of retinoblasto...

  17. A study of tumor suppressor gene expression and promoter methylation for the identification of prognostic markers in glioblastoma

    Vaitkienė Grigaitė, Paulina

    2013-01-01

    Glioblastoma (GBM) is the most common primary brain tumor in adults. This study attempted to identify the genes potentially regulated by promoter methylation in GBM. Therefore, we analyzed the expression of COX7A1, SPINT1, AREG, NPTX2, and KRT81 in glioblastomas and human brain tissue and investigated if there were any associations between the expression and methylation of these genes. Moreover, we aimed to determine the methylation frequency of 11 genes (AREG, CASP8, CD81, DcR...

  18. Nested methylation-specific polymerase chain reaction cancer detection method

    Belinsky, Steven A.; Palmisano, William A.

    2007-05-08

    A molecular marker-based method for monitoring and detecting cancer in humans. Aberrant methylation of gene promoters is a marker for cancer risk in humans. A two-stage, or "nested" polymerase chain reaction method is disclosed for detecting methylated DNA sequences at sufficiently high levels of sensitivity to permit cancer screening in biological fluid samples, such as sputum, obtained non-invasively. The method is for detecting the aberrant methylation of the p16 gene, O 6-methylguanine-DNA methyltransferase gene, Death-associated protein kinase gene, RAS-associated family 1 gene, or other gene promoters. The method offers a potentially powerful approach to population-based screening for the detection of lung and other cancers.

  19. DNA methylation status of nuclear-encoded mitochondrial genes underlies the tissue-dependent mitochondrial functions

    Takasugi Masaki

    2010-08-01

    Full Text Available Abstract Background Mitochondria are semi-autonomous, semi-self-replicating organelles harboring their own DNA (mitochondrial DNA, mtDNA, and their dysregulation is involved in the development of various diseases. While mtDNA does not generally undergo epigenetic modifications, almost all mitochondrial proteins are encoded by nuclear DNA. However, the epigenetic regulation of nuclear-encoded mitochondrial genes (nuclear mt genes has not been comprehensively analyzed. Results We analyzed the DNA methylation status of 899 nuclear mt genes in the liver, brain, and heart tissues of mouse, and identified 636 nuclear mt genes carrying tissue-dependent and differentially methylated regions (T-DMRs. These nuclar mt genes are involved in various mitochondrial functions and they also include genes related to human diseases. T-DMRs regulate the expression of nuclear mt genes. Nuclear mt genes with tissue-specific hypomethylated T-DMRs were characterized by enrichment of the target genes of specific transcription factors such as FOXA2 in the liver, and CEBPA and STAT1 in the brain. Conclusions A substantial proportion of nuclear mt genes contained T-DMRs, and the DNA methylation status of numerous T-DMRs should underlie tissue-dependent mitochondrial functions.

  20. Aberrant gene expression and sexually incompatible genomic imprinting in oocytes derived from XY mouse embryonic stem cells in vitro.

    Mai Nitta

    Full Text Available Mouse embryonic stem cells (ESCs have the potential to differentiate into germ cells (GCs in vivo and in vitro. Interestingly, XY ESCs can give rise to both male and female GCs in culture, irrespective of the genetic sex. Recent studies showed that ESC-derived primordial GCs contributed to functional gametogenesis in vivo; however, in vitro differentiation techniques have never succeeded in generating mature oocytes from ESCs due to cryptogenic growth arrest during the preantral follicle stages of development. To address this issue, a mouse ESC line, capable of producing follicle-like structures (FLSs efficiently, was established to investigate their properties using conventional molecular biological methods. The results revealed that the ESC-derived FLSs were morphologically similar to ovarian primary-to-secondary follicles but never formed an antrum; instead, the FLSs eventually underwent abnormal development or cell death in culture, or formed teratomas when transplanted under the kidney capsule in mice. Gene expression analyses demonstrated that the FLSs lacked transcripts for genes essential to late folliculogenesis, including gonadotropin receptors and steroidogenic enzymes, whereas some other genes were overexpressed in FLSs compared to the adult ovary. The E-Cadherin protein, which is involved in cell-to-cell interactions, was also expressed ectopically. Remarkably, it was seen that oocyte-like cells in the FLSs exhibited androgenetic genomic imprinting, which is ordinarily indicative of male GCs. Although the FLSs did not express male GC marker genes, the DNA methyltransferase, Dnmt3L, was expressed at an abnormally high level. Furthermore, the expression of sex determination factors was ambiguous in FLSs as both male and female determinants were expressed weakly. These data suggest that the developmental dysfunction of the ESC-derived FLSs may be attributable to aberrant gene expression and genomic imprinting, possibly associated with

  1. Methylation of DAPK and THBS1 genes in esophageal gastric-type columnar metaplasia

    Herrera-Goepfert, Roberto; Oñate-Ocaña, Luis F; Mosqueda-Vargas, José Luis; Herrera, Luis A; Castro, Clementina; Mendoza, Julia; González-Barrios, Rodrigo

    2016-01-01

    AIM: To explore methylation of DAPK, THBS1, CDH-1, and p14 genes, and Helicobacter pylori (H. pylori) status in individuals harboring esophageal columnar metaplasia. METHODS: Distal esophageal mucosal samples obtained by endoscopy and histologically diagnosed as gastric-type (non-specialized) columnar metaplasia, were studied thoroughly. DNA was extracted from paraffin blocks, and methylation status of death-associated protein kinase (DAPK), thrombospondin-1 (THBS1), cadherin-1 (CDH1), and p14 genes, was examined using a methyl-sensitive polymerase chain reaction (MS-PCR) and sodium bisulfite modification protocol. H. pylori cagA status was determined by PCR. RESULTS: In total, 68 subjects (33 females and 35 males), with a mean age of 52 years, were included. H. pylori cagA positive was present in the esophageal gastric-type metaplastic mucosa of 18 individuals. DAPK, THSB1, CDH1, and p14 gene promoters were methylated by MS-PCR in 40 (58.8%), 33 (48.5%), 46 (67.6%), and 23 (33.8%) cases of the 68 esophageal samples. H. pylori status was associated with methylation of DAPK (P = 0.003) and THBS1 (P = 0.019). CONCLUSION: DNA methylation occurs in cases of gastric-type (non-specialized) columnar metaplasia of the esophagus, and this modification is associated with H. pylori cagA positive infection. PMID:27182166

  2. The 14-3-3σ gene promoter is methylated in both human melanocytes and melanoma

    Recent evidence demonstrates that 14-3-3σ acts as a tumor suppressor gene inactivated by methylation of its 5' CpG islands in epithelial tumor cells, while remaining un-methylated in normal human epithelia. The methylation analysis of 14-3-3σ has been largely overlooked in melanoma. The methylation status of 14-3-3σ CpG island in melanocytes and melanoma cells was analyzed by methylation-specific sequencing (MSS) and quantitative methylation-specific PCR (Q-MSP). 14-3-3σ mRNA and protein expression in cell lines was detected by real-time RT-PCR and western blot. Melanoma cells were also treated by 5-aza-2'-deoxycytidine (DAC), a demethylating agent, and/or histone deacetylase inhibitor, Trichostatin A (TSA), to evaluate their effects on 14-3-3σ gene expression. 14-3-3σ is hypermethylated in both human melanocytes and most melanoma cells in a lineage-specific manner, resulting in the silencing of 14-3-3σ gene expression and the active induction of 14-3-3σ mRNA and protein expression following treatment with DAC. We also observed a synergistic effect upon gene expression when DAC was combined with TSA. The promoter methylation status of 14-3-3σ was analyzed utilizing Q-MSP in 20 melanoma tissue samples and 10 cell lines derived from these samples, showing that the majority of melanoma samples maintain their hypermethylation status of the 14-3-3σ gene. 14-3-3σ is hypermethylated in human melanoma in a cell-linage specific manner. Spontaneous demethylation and re-expression of 14-3-3σ is a rare event in melanoma, indicating 14-3-3σ might have a tentative role in the pathogenesis of melanoma

  3. The screening of DNA methylation gene modules in cancers%癌症中DNA甲基化基因模块筛选

    张淑梅; 张彬; 刘军厚; 刘洪波; 苏建忠; 王芳; 张岩

    2014-01-01

    肿瘤的发生受遗传学和表观遗传学修饰的共同影响。 DNA甲基化是一种重要的表观遗传修饰,在癌症的发生与发展中起着重大的作用。因此找到癌症的甲基化标记物在癌症的诊断和治疗中具有重大意义。本文利用权重基因共表达网络分析的方法( WGCNA)筛选出甲基化基因模块,并分析模块向量基因,进行功能注释,最后对基因模块进行功能分析,得到DNA甲基化与肿瘤间的关系。结果显示,这些甲基化异常的基因模块与癌症的发生有着显著的关联。同时还发现某些甲基化异常的基因模块与多种癌症的发生都有着显著的关联。%Tumorigenesis is affected by both genetic and epigenetic modifications. DNA methylation acts as an important epigenetic modification and plays a major role in the occurrence and development of cancers. Therefore, finding the methylation biomarkers in cancers is a great feat in the diagnosis and treatment of cancers. In this paper, we take the advantage of Weight Gene Co-expression Network Analysis method( WGCNA) to filter out methylation gene modules and analyze the module vector genes, afterwards, the functional annotation, then we conduct functional analysis of gene modules, finally the relationship between DNA methylation and cancers can be interpreted. The results showed that these aberrant methylated gene modules have significant associations with cancers. Interestingly,we also found that some abnormal methylation gene modules have great associations with the occurrences of various cancers.

  4. [Neuroepigenetics: Desoxyribonucleic acid methylation in Alzheimer's disease and other dementias].

    Mendioroz Iriarte, Maite; Pulido Fontes, Laura; Méndez-López, Iván

    2015-05-21

    DNA methylation is an epigenetic mechanism that controls gene expression. In Alzheimer's disease (AD), global DNA hypomethylation of neurons has been described in the human cerebral cortex. Moreover, several variants in the methylation pattern of candidate genes have been identified in brain tissue when comparing AD patients and controls. Specifically, DNA methylation changes have been observed in PSEN1 and APOE, both genes previously being involved in the pathophysiology of AD. In other degenerative dementias, methylation variants have also been described in key genes, such as hypomethylation of the SNCA gene in Parkinson's disease and dementia with Lewy bodies or hypermethylation of the GRN gene promoter in frontotemporal dementia. The finding of aberrant DNA methylation patterns shared by brain tissue and peripheral blood opens the door to use those variants as epigenetic biomarkers in the diagnosis of neurodegenerative diseases. PMID:24907105

  5. P04.18PROGNOSIS IMPACT OF THE REGIONAL DISTRIBUTION OF MGMT GENE METHYLATION ACCORDING TO THE CPGISLAND METHYLATOR PHENOTYPE AND AGE IN HIGH-GRADE GLIOMAS

    Mur, P.; de Lope, A. Rodriguez; Hernandez-Iglesias, T.; Diaz, F.; Ribalta, T.; Fiaño, C.; Garcia, J.F.; Rey, J.A.; Mollejo, M.; Meléndez, B.

    2014-01-01

    Clinical and molecular prognostic factors in gliomas include age, IDH mutation, the glioma CpG island methylator phenotype (G-CIMP) and promoter methylation of the O6-methylguanine DNA-methyltransferase (MGMT) gene, among others. Clinical trials supported the predictive value of MGMT promoter methylation for benefit from alkylating chemotherapy in elderly GBM patients. In this study, methylation data were obtained from 46 oligodendroglial samples with the Illumina 450K platform, and were analyzed with external data to reach a total 247 glioma samples. MGMT gene methylation analysis with this platform revealed two significant survival-associated CpG regions, one within the promoter (cg12981137) and the other within the gene body (cg07933035), both significantly associated with better overall survival (OS) and strongly correlated with the G-CIMP+ status. However, although around 50% of G-CIMP- tumors were MGMT methylated on these CpG sites, their prognostic relevance were not observed in these patients. Only the gene body methylation was prognostic, but in the context of age, showing significant differences of OS in elderly patients. The absence of the MGMT promoter prognostic value in G-CIMP- tumors was validated in an independent series of 59 chemoradiated GBM patients by MSP and qMSP assays. Our study suggests that the prognostic value of MGMT methylation should be reviewed in the context of specific G-CIMP profiles and age groups. Further analysis on the impact of MGMT methylation on gene and protein expression is necessary for better clinical treatment settings. The routine use of MGMT methylation for the individual treatment of patients should be still viewed with caution.

  6. Epigenetic characterization of the FMR1 gene and aberrant neurodevelopment in human induced pluripotent stem cell models of fragile X syndrome.

    Steven D Sheridan

    Full Text Available Fragile X syndrome (FXS is the most common inherited cause of intellectual disability. In addition to cognitive deficits, FXS patients exhibit hyperactivity, attention deficits, social difficulties, anxiety, and other autistic-like behaviors. FXS is caused by an expanded CGG trinucleotide repeat in the 5' untranslated region of the Fragile X Mental Retardation (FMR1 gene leading to epigenetic silencing and loss of expression of the Fragile X Mental Retardation protein (FMRP. Despite the known relationship between FMR1 CGG repeat expansion and FMR1 silencing, the epigenetic modifications observed at the FMR1 locus, and the consequences of the loss of FMRP on human neurodevelopment and neuronal function remain poorly understood. To address these limitations, we report on the generation of induced pluripotent stem cell (iPSC lines from multiple patients with FXS and the characterization of their differentiation into post-mitotic neurons and glia. We show that clones from reprogrammed FXS patient fibroblast lines exhibit variation with respect to the predominant CGG-repeat length in the FMR1 gene. In two cases, iPSC clones contained predominant CGG-repeat lengths shorter than measured in corresponding input population of fibroblasts. In another instance, reprogramming a mosaic patient having both normal and pre-mutation length CGG repeats resulted in genetically matched iPSC clonal lines differing in FMR1 promoter CpG methylation and FMRP expression. Using this panel of patient-specific, FXS iPSC models, we demonstrate aberrant neuronal differentiation from FXS iPSCs that is directly correlated with epigenetic modification of the FMR1 gene and a loss of FMRP expression. Overall, these findings provide evidence for a key role for FMRP early in human neurodevelopment prior to synaptogenesis and have implications for modeling of FXS using iPSC technology. By revealing disease-associated cellular phenotypes in human neurons, these iPSC models will aid

  7. Interleukin-6 Promotes Tumorigenesis by Altering DNA Methylation in Oral Cancer Cells

    Gasche, Jacqueline A; Hoffmann, Jürgen; Boland, C. Richard; Goel, Ajay

    2011-01-01

    Worldwide oral squamous cell carcinoma (OSCC) accounts for more than 100,000 deaths each year. Chronic inflammation constitutes one of the key risk factors for OSCC. Accumulating evidence suggests that aberrant DNA methylation may contribute to OSCC tumorigenesis. This study investigated whether chronic inflammation alters DNA methylation and expression of cancer-associated genes in OSCC.

  8. A genome-wide study of DNA methylation patterns and gene expression levels in multiple human and chimpanzee tissues.

    Athma A Pai

    2011-02-01

    Full Text Available The modification of DNA by methylation is an important epigenetic mechanism that affects the spatial and temporal regulation of gene expression. Methylation patterns have been described in many contexts within and across a range of species. However, the extent to which changes in methylation might underlie inter-species differences in gene regulation, in particular between humans and other primates, has not yet been studied. To this end, we studied DNA methylation patterns in livers, hearts, and kidneys from multiple humans and chimpanzees, using tissue samples for which genome-wide gene expression data were also available. Using the multi-species gene expression and methylation data for 7,723 genes, we were able to study the role of promoter DNA methylation in the evolution of gene regulation across tissues and species. We found that inter-tissue methylation patterns are often conserved between humans and chimpanzees. However, we also found a large number of gene expression differences between species that might be explained, at least in part, by corresponding differences in methylation levels. In particular, we estimate that, in the tissues we studied, inter-species differences in promoter methylation might underlie as much as 12%-18% of differences in gene expression levels between humans and chimpanzees.

  9. Correlation of SHOX2 Gene Amplification and DNA Methylation in Lung Cancer Tumors

    DNA methylation in the SHOX2 locus was previously used to reliably detect lung cancer in a group of critical controls, including 'cytologically negative' samples with no visible tumor cell content, at a high specificity based on the analysis of bronchial lavage samples. This study aimed to investigate, if the methylation correlates with SHOX2 gene expression and/or copy number alterations. An amplification of the SHOX2 gene locus together with the observed tumor-specific hypermethylation might explain the good performance of this marker in bronchial lavage samples. SHOX2 expression, gene copy number and DNA methylation were determined in lung tumor tissues and matched morphologically normal adjacent tissues (NAT) from 55 lung cancer patients. Quantitative HeavyMethyl (HM) real-time PCR was used to detect SHOX2 DNA methylation levels. SHOX2 expression was assayed with quantitative real-time PCR, and copy numbers alterations were measured with conventional real-time PCR and array CGH. A hypermethylation of the SHOX2 locus in tumor tissue as compared to the matched NAT from the same patient was detected in 96% of tumors from a group of 55 lung cancer patients. This correlated highly significantly with the frequent occurrence of copy number amplification (p < 0.0001), while the expression of the SHOX2 gene showed no difference. Frequent gene amplification correlated with hypermethylation of the SHOX2 gene locus. This concerted effect qualifies SHOX2 DNA methylation as a biomarker for lung cancer diagnosis, especially when sensitive detection is needed, i.e. in bronchial lavage or blood samples

  10. Correlation of SHOX2 Gene Amplification and DNA Methylation in Lung Cancer Tumors

    Liebenberg Volker

    2011-03-01

    Full Text Available Abstract Background DNA methylation in the SHOX2 locus was previously used to reliably detect lung cancer in a group of critical controls, including 'cytologically negative' samples with no visible tumor cell content, at a high specificity based on the analysis of bronchial lavage samples. This study aimed to investigate, if the methylation correlates with SHOX2 gene expression and/or copy number alterations. An amplification of the SHOX2 gene locus together with the observed tumor-specific hypermethylation might explain the good performance of this marker in bronchial lavage samples. Methods SHOX2 expression, gene copy number and DNA methylation were determined in lung tumor tissues and matched morphologically normal adjacent tissues (NAT from 55 lung cancer patients. Quantitative HeavyMethyl (HM real-time PCR was used to detect SHOX2 DNA methylation levels. SHOX2 expression was assayed with quantitative real-time PCR, and copy numbers alterations were measured with conventional real-time PCR and array CGH. Results A hypermethylation of the SHOX2 locus in tumor tissue as compared to the matched NAT from the same patient was detected in 96% of tumors from a group of 55 lung cancer patients. This correlated highly significantly with the frequent occurrence of copy number amplification (p SHOX2 gene showed no difference. Conclusions Frequent gene amplification correlated with hypermethylation of the SHOX2 gene locus. This concerted effect qualifies SHOX2 DNA methylation as a biomarker for lung cancer diagnosis, especially when sensitive detection is needed, i.e. in bronchial lavage or blood samples.

  11. Do aberrant crypt foci have predictive value for the occurrence of colorectal tumours? Potential of gene expression profiling in tumours.

    Wijnands, M V W; van Erk, M J; Doornbos, R P; Krul, C A M; Woutersen, R A

    2004-10-01

    The effects of different dietary compounds on the formation of aberrant crypt foci (ACF) and colorectal tumours and on the expression of a selection of genes were studied in rats. Azoxymethane-treated male F344 rats were fed either a control diet or a diet containing 10% wheat bran (WB), 0.2% curcumin (CUR), 4% rutin (RUT) or 0.04% benzyl isothiocyanate (BIT) for 8 months. ACF were counted after 7, 15 and 26 weeks. Tumours were scored after 26 weeks and 8 months. We found that the WB and CUR diets inhibited the development of colorectal tumours. In contrast, the RUT and BIT diets rather enhanced (although not statistically significantly) colorectal carcinogenesis. In addition, the various compounds caused different effects on the development of ACF. In most cases the number or size of ACF was not predictive for the ultimate tumour yield. The expression of some tumour-related genes was significantly different in tumours from the control group as compared to tumours from the treated groups. It was concluded that WB and CUR, as opposed to RUT and BIT, protects against colorectal cancer and that ACF are unsuitable as biomarker for colorectal cancer. Effects of the different dietary compounds on metalloproteinase 1 (TIMP-1) expression correlated well with the effects of the dietary compounds on the ultimate tumour yield. PMID:15304309

  12. DNA methylation in glioblastoma: impact on gene expression and clinical outcome

    Saikali Stephan

    2010-12-01

    Full Text Available Abstract Background Changes in promoter DNA methylation pattern of genes involved in key biological pathways have been reported in glioblastoma. Genome-wide assessments of DNA methylation levels are now required to decipher the epigenetic events involved in the aggressive phenotype of glioblastoma, and to guide new treatment strategies. Results We performed a whole-genome integrative analysis of methylation and gene expression profiles in 40 newly diagnosed glioblastoma patients. We also screened for associations between the level of methylation of CpG sites and overall survival in a cohort of 50 patients uniformly treated by surgery, radiotherapy and chemotherapy with concomitant and adjuvant temozolomide (STUPP protocol. The methylation analysis identified 616 CpG sites differentially methylated between glioblastoma and control brain, a quarter of which was differentially expressed in a concordant way. Thirteen of the genes with concordant CpG sites displayed an inverse correlation between promoter methylation and expression level in glioblastomas: B3GNT5, FABP7, ZNF217, BST2, OAS1, SLC13A5, GSTM5, ME1, UBXD3, TSPYL5, FAAH, C7orf13, and C3orf14. Survival analysis identified six CpG sites associated with overall survival. SOX10 promoter methylation status (two CpG sites stratified patients similarly to MGMT status, but with a higher Area Under the Curve (0.78 vs. 0.71, p-value FNDC3B, TBX3, DGKI, and FSD1 promoters identified patients with MGMT-methylated tumors that did not respond to STUPP treatment (p-value Conclusions This study provides the first genome-wide integrative analysis of DNA methylation and gene expression profiles obtained from the same GBM cohort. We also present a methylome-based survival analysis for one of the largest uniformly treated GBM cohort ever studied, for more than 27,000 CpG sites. We have identified genes whose expression may be tightly regulated by epigenetic mechanisms and markers that may guide treatment

  13. Functional annotation of rare gene aberration drivers of pancreatic cancer | Office of Cancer Genomics

    As we enter the era of precision medicine, characterization of cancer genomes will directly influence therapeutic decisions in the clinic. Here we describe a platform enabling functionalization of rare gene mutations through their high-throughput construction, molecular barcoding and delivery to cancer models for in vivo tumour driver screens. We apply these technologies to identify oncogenic drivers of pancreatic ductal adenocarcinoma (PDAC).

  14. Procedures to view aberrations-A travel from protein to gene: Literature review

    B Premalatha

    2014-01-01

    Full Text Available The diagnosis of any pathology is fundamentally based on the microscopic structure of cells and tissues and this remains as the standard by which all other diagnostic tests are measured. In this era, the pathologists are relying on the examination of tissue section stained by histochemical means and it is supported by the advanced immunological, biochemical and molecular techniques. This review will provide the information about one of the way that can be followed to unravel the molecular mechanism in spotting the disease process. Technologies used to study the cellular process are same for the normal and the abnormal cell. Experimental strategy briefed here is also applicable for both. The cellular process can be studied either from protein to gene or from gene to protein. Earlier days biochemical analysis (isolation of protein, protein sequencing was separate and genetic analysis (genomic mapping was separate. But now with advent of recombinant DNA technology it is possible to have a link between the biochemical and genetic analysis. Intermediary step of development of oligonucleotide synthesis, complementary DNA probe and cloning has revolutionized the research process. Identified gene can be compared with the normal gene by comparative genomics or expressed proteins by expression proteomics.

  15. Effects of aberrant Pax6 gene dosage on mouse corneal pathophysiology and corneal epithelial homeostasis.

    Richard L Mort

    Full Text Available Altered dosage of the transcription factor PAX6 causes multiple human eye pathophysiologies. PAX6⁺/⁻ heterozygotes suffer from aniridia and aniridia-related keratopathy (ARK, a corneal deterioration that probably involves a limbal epithelial stem cell (LESC deficiency. Heterozygous Pax6(+/Sey-Neu (Pax6⁺/⁻ mice recapitulate the human disease and are a good model of ARK. Corneal pathologies also occur in other mouse Pax6 mutants and in PAX77(Tg/- transgenics, which over-express Pax6 and model human PAX6 duplication.We used electron microscopy to investigate ocular defects in Pax6⁺/⁻ heterozygotes (low Pax6 levels and PAX77(Tg/- transgenics (high Pax6 levels. As well as the well-documented epithelial defects, aberrant Pax6 dosage had profound effects on the corneal stroma and endothelium in both genotypes, including cellular vacuolation, similar to that reported for human macular corneal dystrophy. We used mosaic expression of an X-linked LacZ transgene in X-inactivation mosaic female (XLacZ(Tg/- mice to investigate corneal epithelial maintenance by LESC clones in Pax6⁺/⁻ and PAX77(Tg/- mosaic mice. PAX77(Tg/- mosaics, over-expressing Pax6, produced normal corneal epithelial radial striped patterns (despite other corneal defects, suggesting that centripetal cell movement was unaffected. Moderately disrupted patterns in Pax6⁺/⁻ mosaics were corrected by introducing the PAX77 transgene (in Pax6⁺/⁻, PAX77(Tg/- mosaics. Pax6(Leca4/+, XLacZ(Tg/- mosaic mice (heterozygous for the Pax6(Leca4 missense mutation showed more severely disrupted mosaic patterns. Corrected corneal epithelial stripe numbers (an indirect estimate of active LESC clone numbers declined with age (between 15 and 30 weeks in wild-type XLacZ(Tg/- mosaics. In contrast, corrected stripe numbers were already low at 15 weeks in Pax6⁺/⁻ and PAX77(Tg/- mosaic corneas, suggesting Pax6 under- and over-expression both affect LESC clones.Pax6⁺/⁻ and PAX77(Tg

  16. Methylation of the SPARC gene promoter and its clinical implication in pancreatic cancer

    Lv Shunli

    2010-03-01

    Full Text Available Abstract Background The secreted protein acidic and rich in cysteine (SPARC plays a pivotal role in regulating cell-matrix interactions and tumor angiogenesis, proliferation, and migration. Detection of SPARC gene methylation may be useful as a tumorigenesis marker for early detection of pancreatic cancer. Methods Methylation of the SPARC gene transcriptional regulation region (TRR was detected using bisulfite-specific (BSP PCR-based sequencing analysis in 40 cases of pancreatic cancer and the adjacent normal tissues, 6 chronic pancreatitis tissues, and 6 normal pancreatic tissues. BSP cloning-based sequencing analysis was also performed in selected cases. Clinicopathological data from the cancer patients were collected and analyzed. Results Analysis of SPARC gene TRR methylation showed two hypermethylation wave peak regions: CpG Region 1 (CpG site 1-7 and CpG Region 2 (CpG site 8-12. Pancreatic tissues have shown methylation in both regions with gradual increases from normal, chronic pancreatitis, and adjacent normal tissues to cancerous tissues. However, Methylation of CpG Region 2 was more sensitive than CpG Region 1 in pancreatic tumorigenesis. Furthermore, the methylation level of CpG Region 2 was associated with increased tumor size and exposure to the risk factors (tobacco smoke and alcohol consumption for developing pancreatic cancer. Conclusion Methylation of the SPARC gene, specifically CpG Region 2, may be an early event during pancreatic tumorigenesis and should be further evaluated as a tumorigenesis marker for early detection of pancreatic cancer.

  17. De novo DNA methylation promoted by G9a prevents reprogramming of embryonically silenced genes

    Epsztejn-Litman, Silvina; Feldman, Nirit; Abu-Remaileh, Monther; Shufaro, Yoel; Gerson, Ariela; Ueda, Jun; Deplus, Rachel; Fuks, François; Shinkai, Yoichi; Cedar, Howard; Bergman, Yehudit

    2008-01-01

    The pluripotency determining gene, Oct-3/4 (also called Pou5f1) undergoes post implantation silencing in a process mediated by the histone methyltransferase (HMT) G9a. Microarray analysis now shows that this enzyme may operate as a master regulator that inactivates multiple early embryonic genes by bringing about methylated-histone H3K9 heterochromatinization and de novo DNA methylation. Genetic studies in differentiating ES cells demonstrate that a point mutation in the G9a SET domain preven...

  18. Methylation status of the interferon-gamma gene promoter in chronic hepatitis B

    2008-01-01

    Objective To evaluate the methylation status at CpG site -55 in the interferon-gamma (IFN-γ) gene promoter and its effect on IFN-γ expression in chronic hepatitis B. Method The authors recruited 30 patients with HBeAg-positive chronic hepatitis B (CHB), 30 HBeAg-negative CHB patients, and 30 healthy blood donors. Pyrosequencing was used to determine the methylation status at CpG site -55 in the IFN-γ gene promoter following bisulfite treatment of DNA in peripheral blood mononuclear cells (PBMCs). The expres...

  19. DNA Methylation

    İzmirli, Müzeyyen; Tufan, Turan; Alptekin, Davut

    2012-01-01

    Methylation is a chemical reaction in biological systems for normal genome regulation and development. It is a well known type of epigenetic mechanism. Methylation which regulates gene expression via epigenetic events like gene activation, repression, and chromatin remodelling, consists of two methylation systems. One of these systems is DNA methylation whereas the other is protein (histone) methylation. These systems are associated with some fundamental abnormalities and diseases. This revi...

  20. DNA Methylation

    Muzeyyen Izmirli; Turan Tufan; Davut Alptekin

    2012-01-01

    Methylation is a chemical reaction in biological systems for normal genome regulation and development. It is a well known type of epigenetic mechanism. Methylation which regulates gene expression via epigenetic events like gene activation, repression, and chromatin remodelling, consists of two methylation systems. One of these systems is DNA methylation whereas the other is protein (histone) methylation. These systems are associated with some fundamental abnormalities and diseases. This revie...

  1. Classification of Breast Cancer Subtypes by combining Gene Expression and DNA Methylation Data

    List, Markus; Hauschild, Anne-Christin; Tan, Qihua;

    2014-01-01

    Selecting the most promising treatment strategy for breast cancer crucially depends on determining the correct subtype. In recent years, gene expression profiling has been investigated as an alternative to histochemical methods. Since databases like TCGA provide easy and unrestricted access to gene......-20% and classification error of 1-50%, depending on breast cancer subtype and model. The gene expression model was clearly superior to the methylation model, which was also reflected in the combined model, which mainly selected features from gene expression data. However, the methylation model was able to identify...... unique features not considered as relevant by the gene expression model, which might provide deeper insights into breast cancer subtype differentiation on an epigenetic level....

  2. Methylation pattern of the O6-methylguanine-DNA methyltransferase gene in colon during progressive colorectal tumorigenesis

    NAGASAKA, Takeshi; Goel, Ajay; Notohara, Kenji; Takahata, Takaomi; Sasamoto, Hiromi; Uchida, Takuyuki; Nishida, Naoshi; Tanaka, Noriaki; Boland, Clement Richard; Matsubara, Nagahide

    2008-01-01

    O6-methylguanine-DNA methyltransferase (MGMT) is a DNA repair gene which is frequently methylated in colorectal cancer (CRC). However, it remains controversial whether methylation of specific CpG sequences within MGMT promoter leads to loss of its protein expression, and if MGMT methylation correlates with G to A transition mutations in KRAS. Two methylation sensitive regions (Mp and Eh region) of MGMT promoter were investigated in 593 specimens of colorectal tissue: 233 CRCs, 104 adenomatous...

  3. Aberrant Promoter Hypomethylation in CLL: Does It Matter for Disease Development?

    Upchurch, Garland Michael; Haney, Staci L.; Opavsky, Rene

    2016-01-01

    Over the last 30 years, studies of aberrant DNA methylation in hematologic malignancies have been dominated by the primary focus of understanding promoter hypermethylation. These efforts not only resulted in a better understanding of the basis of epigenetic silencing of tumor suppressor genes but also resulted in approval of hypomethylating agents for the treatment of several malignancies, such as myelodysplastic syndrome and acute myeloid leukemia. Recent advances in global methylation profiling coupled with the use of mouse models suggest that aberrant promoter hypomethylation is also a frequent event in hematologic malignancies, particularly in chronic lymphocytic leukemia (CLL). Promoter hypomethylation affects gene expression and, therefore, may play an important role in disease pathogenesis. Here, we review recent findings and discuss the potential involvement of aberrant promoter hypomethylation in CLL. PMID:27563627

  4. Aberrantly Expressed Genes in HaCaT Keratinocytes Chronically Exposed to Arsenic Trioxide

    Udensi, Udensi K; Cohly, Hari H.P.; Barbara E. Graham-Evans; Kenneth Ndebele; Natàlia Garcia-Reyero; Bindu Nanduri; Tchounwou, Paul B.; Isokpehi, Raphael D.

    2011-01-01

    Inorganic arsenic is a known environmental toxicant and carcinogen of global public health concern. Arsenic is genotoxic and cytotoxic to human keratinocytes. However, the biological pathways perturbed in keratinocytes by low chronic dose inorganic arsenic are not completely understood. The objective of the investigation was to discover the mechanism of arsenic carcinogenicity in human epidermal keratinocytes. We hypothesize that a combined strategy of DNA microarray, qRT-PCR and gene functio...

  5. Cell-specific DNA methylation patterns of retina-specific genes.

    Shannath L Merbs

    Full Text Available Many studies have demonstrated that epigenetic mechanisms are important in the regulation of gene expression during embryogenesis, gametogenesis, and other forms of tissue-specific gene regulation. We sought to explore the possible role of epigenetics, specifically DNA methylation, in the establishment and maintenance of cell type-restricted gene expression in the retina. To assess the relationship between DNA methylation status and expression level of retinal genes, bisulfite sequence analysis of the 1000 bp region around the transcription start sites (TSS of representative rod and cone photoreceptor-specific genes and gene expression analysis were performed in the WERI and Y79 human retinoblastoma cell lines. Next, the homologous genes in mouse were bisulfite sequenced in the retina and in non-expressing tissues. Finally, bisulfite sequencing was performed on isolated photoreceptor and non-photoreceptor retinal cells isolated by laser capture microdissection. Differential methylation of rhodopsin (RHO, retinal binding protein 3 (RBP3, IRBP cone opsin, short-wave-sensitive (OPN1SW, cone opsin, middle-wave-sensitive (OPN1MW, and cone opsin, long-wave-sensitive (OPN1LW was found in the retinoblastoma cell lines that inversely correlated with gene expression levels. Similarly, we found tissue-specific hypomethylation of the promoter region of Rho and Rbp3 in mouse retina as compared to non-expressing tissues, and also observed hypomethylation of retinal-expressed microRNAs. The Rho and Rbp3 promoter regions were unmethylated in expressing photoreceptor cells and methylated in non-expressing, non-photoreceptor cells from the inner nuclear layer. A third regional hypomethylation pattern of photoreceptor-specific genes was seen in a subpopulation of non-expressing photoreceptors (Rho in cones from the Nrl -/- mouse and Opn1sw in rods. These results demonstrate that a number of photoreceptor-specific genes have cell-specific differential DNA

  6. P07.04PROMOTER METHYLATION OF THE LATS1 AND LATS2 GENES IN SCHWANNOMAS

    Ohta, T.; Oh, J.; Mittelbronn, M.; Paulus, W.; Ohgaki, H.

    2014-01-01

    Schwannoma is a benign nerve sheath tumor that is typically encapsulated and composed of well-differentiated Schwann cellswhich comprises 5-10% of all intracranial tumors in adults. Approximately 90% of schwannomas are solitary and sporadic, whereas ∼4% are considered to arise in the setting of neurofibromatosis type 2 (NF2) syndrome by NF2 germline mutations. The molecular basis of sporadic schwannomas is not fully understood, other than frequent NF2 mutations (∼60%). LATS1 and the related LATS2 are downstream molecules of NF2 and negative regulators of the YAP oncogene in the Salvador/Warts/Hippo (SWH) signaling pathway. Expression of these genes is reduced due to promoter methylation in a variety of neoplasms including gliomas. In the present study, methylation-specific PCR revealed promoter methylation of the LATS1 and LATS2 in 15 of 91 (16%) and 32 of 91 (35%) schwannomas, respectively. These alterations were significantly more frequent in spinal than in peripheral schwannomas (23% vs 3% for LATS1, P = 0.0171; 42% vs 21% for LATS2, P = 0.0386). LATS1 methylation was also detected in 3 of 4 schwannomatosis cases. Furthermore, neurofibroma / schwannoma hybrid tumors showed promoter methylation in LATS1 (3/14; 21%) and LATS2 (8/14; 57%). LATS1 and LATS2 promoter methylation were largely mutually exclusive, and there was a significant negative correlation (P = 0.003); only 10 cases had methylation in both genes. These results suggest that LATS1 and LATS2 promoter methylation may be additional molecular mechanisms resulting in an abnormal SWH pathway in schwannomas and related tumors.

  7. Aberrant Protocadherin17 (PCDH17) Methylation in Serum is a Potential Predictor for Recurrence of Early-Stage Prostate Cancer Patients After Radical Prostatectomy.

    Lin, Ying-Li; Deng, Qiu-Kui; Wang, Yu-Hao; Fu, Xing-Li; Ma, Jian-Guo; Li, Wen-Ping

    2015-01-01

    BACKGROUND Prostate cancer is a one of the most common malignant diseases in men worldwide. Now it is a challenge to identify patients at higher risk for relapse and progression after surgery, and more novel prognostic biomarkers are needed. The aim of this study was to investigate the clinical significance of protocadherin17 (PCDH17) methylation in serum and its predictive value for biochemical recurrence (BCR) after radical prostatectomy. MATERIAL AND METHODS We evaluated the methylation status of PCDH17 in serum samples of 167 early-stage prostate cancer patients and 44 patients with benign prostatic hyperplasia (BPH) using methylation-specific PCR (MSP), and then evaluated the relationship between PCDH17 methylation and clinicopathologic features. Kaplan-Meier survival analysis and Cox analysis were used to evaluate its predictive value for BCR. RESULTS The ratio of PCDH17 methylation in prostate cancer patients was higher than in patients with BPH. Moreover, PCDH17 methylation was significantly associated with advanced pathological stage, higher Gleason score, higher preoperative PSA levels, and BCR. Kaplan-Meier survival analysis indicated that patients with methylated PCDH17 had shorter BCR-free survival time compared to patients with unmethylated PCDH17. Cox regression analysis indicated that PCDH17 methylation was an independent predictive factor for the BCR of patients after radical prostatectomy. CONCLUSIONS PCDH17 methylation in serum is a frequent event in early-stage prostate cancer, and it is an independent predictor of BCR after radical prostatectomy. PMID:26683656

  8. Expression of transferred thymidine kinase genes is controlled by methylation.

    Christy, B.; Scangos, G

    1982-01-01

    Plasmid pTKx-1, containing the herpes simplex virus gene for thymidine kinase (TK) inserted into the BamHI site of plasmid pBR322, was introduced into Ltk- cells by calcium phosphate precipitation in the absence of carrier DNA. Line 101 is a TK+ derivative of Ltk- that contains multiple copies of pTKx-1 in a multimeric structure. A derivative of 101 that retained but no longer expressed the herpes simplex TK genes (termed 101BU1) and derivatives of line 101BU1 that reexpressed the genes (term...

  9. A Meta-analysis of Association between MGMT Gene 
Promoter Methylation and Non-small Cell Lung Cancer

    Fang, Nianzhen; Gu, Jundong; Wei, Huijun; Jiacong YOU; Zhou, Qinghua

    2014-01-01

    Backgroud and objective DNA promoter methylation of the tumor suppressor genes was one of the key mechanism for gene silence. The aim of this study is to investigate the difference of MGMT gene promoter methylation rate in tumor tissue and autologous controls (serum, normal lung tissue and bronchial lavage fluid) in patients with non-small cell lung cancer (NSCLC). Methods The databases of Medline, EMBSE, CNKI and Wanfang were searched for selection of published articles of MGMT gene promoter...

  10. The rules of gene expression in plants: Organ identity and gene body methylation are key factors for regulation of gene expression in Arabidopsis thaliana

    Gutiérrez Rodrigo A

    2008-09-01

    Full Text Available Abstract Background Microarray technology is a widely used approach for monitoring genome-wide gene expression. For Arabidopsis, there are over 1,800 microarray hybridizations representing many different experimental conditions on Affymetrix™ ATH1 gene chips alone. This huge amount of data offers a unique opportunity to infer the principles that govern the regulation of gene expression in plants. Results We used bioinformatics methods to analyze publicly available data obtained using the ATH1 chip from Affymetrix. A total of 1887 ATH1 hybridizations were normalized and filtered to eliminate low-quality hybridizations. We classified and compared control and treatment hybridizations and determined differential gene expression. The largest differences in gene expression were observed when comparing samples obtained from different organs. On average, ten-fold more genes were differentially expressed between organs as compared to any other experimental variable. We defined "gene responsiveness" as the number of comparisons in which a gene changed its expression significantly. We defined genes with the highest and lowest responsiveness levels as hypervariable and housekeeping genes, respectively. Remarkably, housekeeping genes were best distinguished from hypervariable genes by differences in methylation status in their transcribed regions. Moreover, methylation in the transcribed region was inversely correlated (R2 = 0.8 with gene responsiveness on a genome-wide scale. We provide an example of this negative relationship using genes encoding TCA cycle enzymes, by contrasting their regulatory responsiveness to nitrate and methylation status in their transcribed regions. Conclusion Our results indicate that the Arabidopsis transcriptome is largely established during development and is comparatively stable when faced with external perturbations. We suggest a novel functional role for DNA methylation in the transcribed region as a key determinant