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Articles by J. G Herman
Total Records ( 5 ) for J. G Herman
  S de Vogel , M. P Weijenberg , J. G Herman , K. A. D Wouters , A. F. P. M de Goeij , P. A van den Brandt , A. P de Bruine and M. van Engeland
 

Background: To study how caretaker gene silencing relates to gatekeeper mutations in colorectal cancer (CRC), we investigated whether O6-methylguanine DNA methyltransferase (MGMT) and Human Mut-L Homologue 1 (MLH1) promoter hypermethylation are associated with APC, KRAS and BRAF mutations among 734 CRC patients.

Methods: We compared MGMT hypermethylation with G:C > A:T mutations in APC and KRAS and with the occurrence of such mutations in CpG or non-CpG dinucleotides in APC. We also compared MLH1 hypermethylation with truncating APC mutations and activating KRAS and BRAF mutations.

Results: Only 10% of the tumors showed both MGMT and MLH1 hypermethylation. MGMT hypermethylation occurred more frequently in tumors with G:C > A:T KRAS mutations (55%) compared with those without these mutations (38%, P < 0.001). No such difference was observed for G:C > A:T mutations in APC, regardless of whether mutations occurred in CpG or non-CpG dinucleotides. MLH1 hypermethylation was less common in tumors with APC mutations (P = 0.006) or KRAS mutations (P = 0.001), but was positively associated with BRAF mutations (P < 0.001).

Conclusions: MGMT hypermethylation is associated with G:C > A:T mutations in KRAS, but not in APC, suggesting that MGMT hypermethylation may succeed APC mutations but precedes KRAS mutations in colorectal carcinogenesis. MLH1-hypermethylated tumors harbor fewer APC and KRAS mutations and more BRAF mutations, suggesting that they develop distinctly from an MGMT methylator pathway.

  S. C Glockner , M Dhir , J. M Yi , K. E McGarvey , L Van Neste , J Louwagie , T. A Chan , W Kleeberger , A. P de Bruine , K. M Smits , C. A.J Khalid de Bakker , D. M.A.E Jonkers , R. W Stockbrugger , G. A Meijer , F. A Oort , C Iacobuzio Donahue , K Bierau , J. G Herman , S. B Baylin , M Van Engeland , K. E Schuebel and N. Ahuja
 

We have used a gene expression array–based strategy to identify the methylation of tissue factor pathway inhibitor 2 (TFPI2), a potential tumor suppressor gene, as a frequent event in human colorectal cancers (CRC). TFPI2 belongs to the recently described group of embryonic cell Polycomb group (PcG)–marked genes that may be predisposed to aberrant DNA methylation in early stages of colorectal carcinogenesis. Aberrant methylation of TFPI2 was detected in almost all CRC adenomas (97%, n = 56) and stages I to IV CRCs (99%, n = 115). We further explored the potential of TFPI2 as a biomarker for the early detection of CRC using stool DNA–based assays in patients with nonmetastatic CRC and average-risk noncancer controls who were candidates for screening. TFPI2 methylation was detected in stool DNA from stage I to III CRC patients with a sensitivity of 76% to 89% and a specificity of 79% to 93%. Detection of TFPI2 methylation in stool DNA may act as a useful adjunct to the noninvasive strategies for screening of CRCs in the future. [Cancer Res 2009;69(11):4691–9]

  S Derks , L. J.W Bosch , H. E.C Niessen , P. T.M Moerkerk , S. M van den Bosch , B Carvalho , S Mongera , J.W Voncken , G. A Meijer , A. P de Bruine , J. G Herman and M. van Engeland
 

Chromosomal loss of 18q21 is a frequent event in colorectal cancer (CRC) development, suggesting that this region harbors tumor suppressor genes (TSGs). Several candidate TSGs, among which methyl-CpG-binding domain protein 1 (MBD1), CpG-binding protein CXXC1, Sma- and Mad-related protein 4 (SMAD4), deleted in colon cancer (DCC) and methyl-CpG-binding domain protein 2 (MBD2) are closely linked on a 4-Mb DNA region on chromosome18q21. As TSGs can be epigenetically silenced, this study investigates whether MBD1, CXXC1, SMAD4, DCC and MBD2 are subject to epigenetic silencing in CRC. Methylation-specific polymerase chain reaction and sodium bisulfite sequencing of these genes show that DCC, but not MBD1, CXXC1, SMAD4 and MBD2, has promoter CpG island methylation in CRC cell lines and tissues {normal mucosa [29.5% (18/61)], adenomas [81.0% (47/58)] and carcinomas [82.7% (62/75)] (P = 8.6 x 10–9)} that is associated with reduced DCC expression, independent of 18q21 loss analyzed by multiplex ligation-dependent probe amplification. Reduced gene expression of CXXC1, SMAD4 and MBD2 correlates with 18q21 loss in CRC cell lines (P = 0.04, 0.02 and 0.02, respectively). Treatment with the demethylating agent 5-aza-2'-deoxycytidine, but not with the histone deacetylase inhibitor trichostatin A exclusively restored DCC expression in CRC cell lines. Chromatin immunoprecipitation studies reveal that the DCC promoter is marked with repressive histone-tail marks H3K9me3 and H3K27me3, whereas activity related H3K4me3 was absent. Only active epigenetic marks were detected for MBD1, CXXC1, SMAD4 and MBD2. This study demonstrates specific epigenetic silencing of DCC in CRC as a focal process not affecting neighboring genes on chromosomal region 18q21.

  D. M.E.I Hellebrekers , M. H.F.M Lentjes , S. M van den Bosch , V Melotte , K. A.D Wouters , K. L.J Daenen , K. M Smits , Y Akiyama , Y Yuasa , S Sanduleanu , C. A.J Khalid de Bakker , D Jonkers , M. P Weijenberg , J Louwagie , W van Criekinge , B Carvalho , G. A Meijer , S. B Baylin , J. G Herman , A. P de Bruine and M. van Engeland
 

Purpose: The transcription factors GATA4 and GATA5 are involved in gastrointestinal development and are inactivated by promoter hypermethylation in colorectal cancer. Here, we evaluated GATA4/5 promoter methylation as potential biomarkers for noninvasive colorectal cancer detection, and investigated the role of GATA4/5 in colorectal cancer.

Experimental Design: Promoter methylation of GATA4/5 was analyzed in colorectal tissue and fecal DNA from colorectal cancer patients and healthy controls using methylation-specific PCR. The potential function of GATA4/5 as tumor suppressors was studied by inducing GATA4/5 overexpression in human colorectal cancer cell lines.

Results: GATA4/5 methylation was observed in 70% (63/90) and 79% (61/77) of colorectal carcinomas, respectively, and was independent of clinicopathologic features. Methylation frequencies in normal colon tissues from noncancerous controls were 6% (5 of 88, GATA4; P < 0.001) and 13% (13 of 100, GATA5; P < 0.001). GATA4/5 overexpression suppressed colony formation (P < 0.005), proliferation (P < 0.001), migration (P < 0.05), invasion (P < 0.05), and anchorage-independent growth (P < 0.0001) of colorectal cancer cells. Examination of GATA4 methylation in fecal DNA from two independent series of colorectal cancer patients and controls yielded a sensitivity of 71% [95% confidence interval (95% CI), 55-88%] and specificity of 84% (95% CI, 74–95%) for colorectal cancer detection in the training set, and a sensitivity of 51% (95% CI, 37–65%) and specificity of 93% (95% CI, 84-100%) in the validation set.

Conclusions: Methylation of GATA4/5 is a common and specific event in colorectal carcinomas, and GATA4/5 exhibit tumor suppressive effects in colorectal cancer cells in vitro. GATA4 methylation in fecal DNA may be of interest for colorectal cancer detection.

  V. J Bailey , H Easwaran , Y Zhang , E Griffiths , S. A Belinsky , J. G Herman , S. B Baylin , H. E Carraway and T. H. Wang
 

DNA methylation contributes to carcinogenesis by silencing key tumor suppressor genes. Here we report an ultrasensitive and reliable nanotechnology assay, MS-qFRET, for detection and quantification of DNA methylation. Bisulfite-modified DNA is subjected to PCR amplification with primers that would differentiate between methylated and unmethylated DNA. Quantum dots are then used to capture PCR amplicons and determine the methylation status via fluorescence resonance energy transfer (FRET). Key features of MS-qFRET include its low intrinsic background noise, high resolution, and high sensitivity. This approach detects as little as 15 pg of methylated DNA in the presence of a 10,000-fold excess of unmethylated alleles, enables reduced use of PCR (as low as eight cycles), and allows for multiplexed analyses. The high sensitivity of MS-qFRET enables one-step detection of methylation at PYCARD, CDKN2B, and CDKN2A genes in patient sputum samples that contain low concentrations of methylated DNA, which normally would require a nested PCR approach. The direct application of MS-qFRET on clinical samples offers great promise for its translational use in early cancer diagnosis, prognostic assessment of tumor behavior, as well as monitoring response to therapeutic agents.

 
 
 
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