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Yujun Hao,
Chao Wang,
Bo Cao,
Brett M Hirsch,
Jing Song, Sanford D Markowitz,
Rob M Ewing,
David Sedwick,
Lili Liu,
Weiping Zheng,
Zhenghe Wang
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ABSTRACT: PIK3CA, which encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase α, is frequently mutated in human cancers. Most of these mutations occur at two hot-spots: E545K and H1047R located in the helical domain and the kinase domain, respectively. Here, we report that p110α E545K, but not p110α H1047R, gains the ability to associate with IRS1 independent of the p85 regulatory subunit, thereby rewiring this oncogenic signaling pathway. Disruption of the IRS1-p110α E545K interaction destabilizes the p110α protein, reduces AKT phosphorylation, and slows xenograft tumor growth of a cancer cell line expressing p110α E545K. Moreover, a hydrocarbon-stapled peptide that disrupts this interaction inhibits the growth of tumors expressing p110α E545K.
Cancer cell 04/2013; · 25.29 Impact Factor
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ABSTRACT: BACKGROUND AND AIMS: 15-Hydroxprostaglandin dehydrogenase (15-PGDH) mediates a colon neoplasia suppressor pathway, acting through metabolic antagonism of cyclooxygenase-mediated colon carcinogenesis. To determine whether the colon tumor prevention activity of 15-PGDH acts as a constant or variable effect among individuals, we determined whether 15-PGDH levels remain stable over subsite and time in the human colon, determined the extent of differences in 15-PGDH levels between different individuals, and determined whether 15-PGDH modulation mediates any part of the anti-colon tumor effect of aspirin. METHODS: Using real-time PCR, we measured 15-PGDH mRNA to determine the correlation of 15-PGDH level in replicate colon biopsies, in biopsies from throughout the length of the colon, in repeat biopsies taken 4 months apart, and in paired biopsies of individuals taken before and after aspirin treatment, and by Western-blot for 15-PGDH protein in mice. RESULTS: Colonic 15-PGDH levels varied 4.4-fold across the human population. Within individuals, 15-PGDH levels proved highly reproducible (r = 0.81 in duplicate biopsies) and stable along the length of the colon, with average 15-PGDH levels deviating by only 17 % from rectum to cecum. An individual's 15-PGDH levels are also highly stable over time, with a median coefficient of variation over a 4-month interval of only 12 %. Last, colonic 15-PGDH levels proved resistant to alteration by aspirin, with only a 10 % difference in 15-PGDH levels measured before and after aspirin treatment. CONCLUSIONS: 15-PGDH levels vary across the population in a stable and reproducible manner, and are resistant to alteration by aspirin. 15-PGDH represents an independent target for modulation by candidate colon tumor chemopreventive agents.
Digestive Diseases and Sciences 04/2013; · 2.12 Impact Factor
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Cancer Epidemiology Biomarkers & Prevention 08/2012; 21(10):1890. · 4.12 Impact Factor
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ABSTRACT: The advent of Next-Generation sequencing technologies, which significantly increases the throughput and reduces the cost of large-scale sequencing efforts, provides an unprecedented opportunity for discovery of novel gene mutations in human cancers. However, it remains a challenge to apply Next-Generation technologies to DNA extracted from formalin-fixed paraffin-embedded cancer specimens. We describe here the successful development of a custom DNA capture method using Next-Generation for detection of 140 driver genes in five formalin-fixed paraffin-embedded human colon cancer samples using an improved extraction process to produce high-quality DNA. Isolated DNA was enriched for targeted exons and sequenced using the Illumina Next-Generation platform. An analytical pipeline using 3 software platforms to define single-nucleotide variants was used to evaluate the data output. Approximately 250 × average coverage was obtained with >96% of target bases having at least 30 sequence reads. Results were then compared with previously performed high-throughput Sanger sequencing. Using an algorithm of needing a positive call from all three callers to give a positive result, 98% of the verified Sanger sequencing somatic driver gene mutations were identified by our method with a specificity of 90%. In all, 13 insertions and deletions identified by Next-Generation were confirmed by Sanger sequencing. We also applied this technology to two components of a biphasic colon cancer, which had strikingly differing histology. Remarkably, no new driver gene mutation accumulation was identified in the more undifferentiated component. Applying this method to profiling of formalin-fixed paraffin-embedded colon cancer tissue samples yields equivalent sensitivity and specificity for mutation detection as Sanger sequencing of matched cell lines derived from these cancers. This method directly enables high-throughput comprehensive mutational profiling of colon cancer samples, and is easily extendable to enable targeted sequencing from formalin-fixed paraffin-embedded material for other tumor types.Modern Pathology advance online publication, 10 August 2012; doi:10.1038/modpathol.2012.121.
Modern Pathology 08/2012; · 4.79 Impact Factor
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Dheepa Balasubramanian,
Batool Akhtar-Zaidi,
Lingyun Song,
Cynthia F Bartels,
Martina Veigl,
Lydia Beard,
Lois Myeroff,
Kishore Guda,
James Lutterbaugh,
Joseph Willis,
Gregory E Crawford, Sanford D Markowitz,
Peter C Scacheri
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ABSTRACT: BACKGROUND: In addition to mutations, epigenetic silencing of genes has been recognized as a fundamental mechanism that promotes human carcinogenesis. To date, characterization of epigenetic gene silencing has largely focused on genes in which silencing is mediated by hypermethylation of promoter-associated CpG islands, associated with loss of the H3K4me3 chromatin mark. Far less is known about promoters lacking CpG-islands or genes that are repressed by alternative mechanisms. METHODS: We performed integrative ChIP-chip, DNase-seq, and global gene expression analyses in colon cancer cells and normal colon mucosa to characterize chromatin features of both CpG-rich and CpG-poor promoters of genes that undergo silencing in colon cancer. RESULTS: Epigenetically repressed genes in colon cancer separate into two classes based on retention or loss of H3K4me3 at transcription start sites. Quantitatively, of transcriptionally repressed genes that lose H3K4me3 in colon cancer (K4-dependent genes), a large fraction actually lacks CpG islands. Nonetheless, similar to CpG-island containing genes, cytosines located near the start sites of K4-dependent genes become DNA hypermethylated, and repressed K4-dependent genes can be reactivated with 5-azacytidine. Moreover, we also show that when the H3K4me3 mark is retained, silencing of CpG island-associated genes can proceed through an alternative mechanism in which repressive chromatin marks are recruited. CONCLUSIONS: H3K4me3 equally protects from DNA methylation at both CpG-island and non-CpG island start sites in colon cancer. Moreover, the results suggest that CpG-rich genes repressed by loss of H3K4me3 and DNA methylation represent special instances of a more general epigenetic mechanism of gene silencing, one in which gene silencing is mediated by loss of H3K4me3 and methylation of non-CpG island promoter-associated cytosines.
Genome Medicine 05/2012; 4(5):47.
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Rom S Leidner,
Lakshmeswari Ravi,
Patrick Leahy,
Yanwen Chen,
Beth Bednarchik,
Mirte Streppel,
Marcia Canto,
Jean S Wang,
Anirban Maitra,
Joseph Willis, Sanford D Markowitz,
Jill Barnholtz-Sloan,
Mark D Adams,
Amitabh Chak,
Kishore Guda
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ABSTRACT: There is a critical need to identify molecular markers that can reliably aid in stratifying esophageal adenocarcinoma (EAC) risk in patients with Barrett's esophagus. MicroRNAs (miRNA/miR) are one such class of biomolecules. In the present cross-sectional study, we characterized miRNA alterations in progressive stages of neoplastic development, i.e., metaplasia-dysplasia-adenocarcinoma, with an aim to identify candidate miRNAs potentially associated with progression. Using next generation sequencing (NGS) as an agnostic discovery platform, followed by quantitative real-time PCR (qPCR) validation in a total of 20 EACs, we identified 26 miRNAs that are highly and frequently deregulated in EACs (≥ 4-fold in >50% of cases) when compared to paired normal esophageal squamous (nSQ) tissue. We then assessed the 26 EAC-derived miRNAs in laser microdissected biopsy pairs of Barrett's metaplasia (BM)/nSQ (n = 15), and high-grade dysplasia (HGD)/nSQ (n = 14) by qPCR, to map the timing of deregulation during progression from BM to HGD and to EAC. We found that 23 of the 26 candidate miRNAs were deregulated at the earliest step, BM, and therefore noninformative as molecular markers of progression. Two miRNAs, miR-31 and -31*, however, showed frequent downregulation only in HGD and EAC cases suggesting association with transition from BM to HGD. A third miRNA, miR-375, showed marked downregulation exclusively in EACs and in none of the BM or HGD lesions, suggesting its association with progression to invasive carcinoma. Taken together, we propose miR-31 and -375 as novel candidate microRNAs specifically associated with early- and late-stage malignant progression, respectively, in Barrett's esophagus.
Genes Chromosomes and Cancer 05/2012; 51(5):473-9. · 3.31 Impact Factor
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Melinda D Willard,
Mary E Lajiness,
Isabella H Wulur,
Bo Feng,
Michelle L Swearingen,
Mark T Uhlik,
Kenneth W Kinzler,
Victor E Velculescu,
Tobias Sjöblom, Sanford D Markowitz,
Steven M Powell,
Bert Vogelstein,
Thomas D Barber
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ABSTRACT: The roles of cholecystokinin 2 receptor (CCK2R) in numerous physiologic processes in the gastrointestinal tract and central nervous system are well documented. There has been some evidence that CCK2R alterations play a role in cancers, but the functional significance of these alterations for tumorigenesis is unknown. We have identified six mutations in CCK2R among a panel of 140 colorectal cancers and 44 gastric cancers. We show that these mutations increase receptor activity, activate multiple downstream signaling pathways, increase cell migration, and promote angiogenesis. Our findings suggest that somatic mutations in CCK2R may promote tumorigenesis through deregulated receptor activity and highlight the importance of evaluating CCK2R inhibitors to block both the normal and mutant forms of the receptor.
Molecular Cancer Research 04/2012; 10(6):739-49. · 4.29 Impact Factor
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ABSTRACT: We have previously established aberrant DNA methylation of vimentin exon-1 (VIM methylation) as a common epigenetic event in colon cancer and as a biomarker for detecting colon neoplasia. We now examine vimentin methylation in neoplasia of the upper gastrointestinal tract.
Using a quantitative real-time methylation-specific PCR assay, we tested for vimentin methylation in archival specimens of esophageal and gastric neoplasia.
We find that acquisition of aberrant vimentin methylation is highly common in these neoplasms, but largely absent in controls. The highest frequency of vimentin methylation was detected in lesions of the distal esophagus, including 91% of Barrett's esophagus (n = 11), 100% of high-grade dysplasia (HGD, n = 5), and 81% of esophageal adenocarcinoma (EAC, n = 26) but absent in controls (n = 9). Vimentin methylation similarly was detected in 87% of signet ring (n = 15) and 53% of intestinal type gastric cancers (n = 17). Moreover, in tests of cytology brushings vimentin methylation proved detectable in 100% of Barrett's esophagus cases (n = 7), 100% of HGD cases (n = 4), and 83% of EAC cases (n = 18) but was absent in all controls (n = 5).
These findings establish aberrant vimentin methylation as a highly common epigenetic alteration in neoplasia of the upper gastrointestinal tract and show that Barrett's esophagus, even without dysplasia, already contains epigenetic alterations characteristic of adenocarcinoma.
These findings suggest vimentin methylation as a biomarker of upper gastrointestinal neoplasia with potential for development as molecular cytology in esophageal screening.
Cancer Epidemiology Biomarkers & Prevention 03/2012; 21(4):594-600. · 4.12 Impact Factor
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Amitabh Chak,
Yanwen Chen,
Jaime Vengoechea,
Marcia I Canto,
Robert Elston,
Gary W Falk,
William M Grady,
Kishore Guda,
Margaret Kinnard, Sanford Markowitz,
Sumeet Mittal,
Ganapathy Prasad,
Nicholas Shaheen,
Joseph E Willis,
Jill S Barnholtz-Sloan
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ABSTRACT: Genetic influences may be discerned in families that have multiple affected members and may manifest as an earlier age of cancer diagnosis. In this study, we determine whether cancers develop at an earlier age in multiplex Familial Barrett's Esophagus (FBE) kindreds, defined by 3 or more members affected by Barrett's esophagus (BE) or esophageal adenocarcinoma (EAC).
Information on BE/EAC risk factors and family history was collected from probands at eight tertiary care academic hospitals. Age of cancer diagnosis and other risk factors were compared between nonfamilial (no affected relatives), duplex (two affected relatives), and multiplex (three or more affected relatives) FBE kindreds.
The study included 830 nonfamilial, 274 duplex, and 41 multiplex FBE kindreds with 274, 133, and 43 EAC and 566, 288, and 103 BE cases, respectively. Multivariable mixed models adjusting for familial correlations showed that multiplex kindreds were associated with a younger age of cancer diagnosis (P = 0.0186). Median age of cancer diagnosis was significantly younger in multiplex compared with duplex and nonfamilial kindreds (57 vs. 62 vs. 63 years, respectively, P = 0.0448). Mean body mass index was significantly lower in multiplex kindreds (P = 0.0033), as was smoking (P < 0.0001), and reported regurgitation (P = 0.0014).
Members of multiplex FBE kindreds develop EAC at an earlier age compared with nonfamilial EAC cases. Multiplex kindreds do not have a higher proportion of common risk factors for EAC, suggesting that this aggregation might be related to a genetic factor. Impact: These findings indicate that efforts to identify susceptibility genes for BE and EAC will need to focus on multiplex kindreds.
Cancer Epidemiology Biomarkers & Prevention 12/2011; 21(2):376-83. · 4.12 Impact Factor
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Dawang Zhou,
Yongyou Zhang,
Hongtan Wu,
Evan Barry,
Yi Yin,
Earl Lawrence,
Dawn Dawson,
Joseph E Willis, Sanford D Markowitz,
Fernando D Camargo,
Joseph Avruch
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ABSTRACT: Ablation of the kinases Mst1 and Mst2, orthologs of the Drosophila antiproliferative kinase Hippo, from mouse intestinal epithelium caused marked expansion of an undifferentiated stem cell compartment and loss of secretory cells throughout the small and large intestine. Although median survival of mice lacking intestinal Mst1/Mst2 is 13 wk, adenomas of the distal colon are common by this age. Diminished phosphorylation, enhanced abundance, and nuclear localization of the transcriptional coactivator Yes-associated protein 1 (Yap1) is evident in Mst1/Mst2-deficient intestinal epithelium, as is strong activation of β-catenin and Notch signaling. Although biallelic deletion of Yap1 from intestinal epithelium has little effect on intestinal development, inactivation of a single Yap1 allele reduces Yap1 polypeptide abundance to nearly wild-type levels and, despite the continued Yap hypophosphorylation and preferential nuclear localization, normalizes epithelial structure. Thus, supraphysiologic Yap polypeptide levels are necessary to drive intestinal stem cell proliferation. Yap is overexpressed in 68 of 71 human colon cancers and in at least 30 of 36 colon cancer-derived cell lines. In colon-derived cell lines where Yap is overabundant, its depletion strongly reduces β-catenin and Notch signaling and inhibits proliferation and survival. These findings demonstrate that Mst1 and Mst2 actively suppress Yap1 abundance and action in normal intestinal epithelium, an antiproliferative function that frequently is overcome in colon cancer through Yap1 polypeptide overabundance. The dispensability of Yap1 in normal intestinal homeostasis and its potent proliferative and prosurvival actions when overexpressed in colon cancer make it an attractive therapeutic target.
Proceedings of the National Academy of Sciences 12/2011; 108(49):E1312-20. · 9.68 Impact Factor
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ABSTRACT: Mammalian mucin-type O-glycosylation is initiated by a large family of ∼20 UDP-GalNAc:polypeptide α-N-acetylgalactosaminyltransferases (ppGalNAc Ts) that transfer α-GalNAc from UDP-GalNAc to Ser and Thr residues of polypeptide acceptors. Characterizing the peptide substrate specificity of each isoform is critical to understanding their properties, biological roles, and significance. Presently, only the specificities of ppGalNAc T1, T2, and T10 and the fly orthologues of T1 and T2 have been systematically characterized utilizing random peptide substrates. We now extend these studies to ppGalNAc T3, T5, and T12, transferases variously associated with human disease. Our results reveal several common features; the most striking is the similar pattern of enhancements for the three residues C-terminal to the site of glycosylation for those transferases that contain a common conserved Trp. In contrast, residues N-terminal to the site of glycosylation show a wide range of isoform-specific enhancements, with elevated preferences for Pro, Val, and Tyr being the most common at the -1 position. Further analysis reveals that the ratio of positive (Arg, Lys, and His) to negative (Asp and Glu) charged residue enhancements varied among transferases, thus further modulating substrate preference in an isoform-specific manner. By utilizing the obtained transferase-specific preferences, the glycosylation patterns of the ppGalNAc Ts against a series of peptide substrates could roughly be reproduced, demonstrating the potential for predicting isoform-specific glycosylation. We conclude that each ppGalNAc T isoform may be uniquely sensitive to peptide sequence and overall charge, which together dictates the substrate sites that will be glycosylated.
Journal of Biological Chemistry 02/2011; 286(16):14493-507. · 4.77 Impact Factor
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ABSTRACT: The genetic component of colorectal cancer (CRC) predisposition has been only partially explained. We recently suggested that a subtle decrease in the expression of one allele of the TGFBR1 gene was a heritable quantitative trait predisposing to CRC. Here, we refined the measurements of allele-specific expression (ASE) of TGFBR1 in a population-based series of CRC patients and controls. Five single-nucleotide polymorphisms (SNPs) in the 3'-untranslated region of the gene were genotyped and used for ASE determination by pyrosequencing. After eliminating non-informative samples and samples with RNA of insufficient quality 109 cases and 125 controls were studied. Allelic ratios ranged between 0.74 and 1.69 without evidence of bimodality or cutoff points for 'ASE' versus 'non-ASE'. Treating ASE as a continuous variable, cases had non-significantly different values than controls (P = 0.081 when comparing means by permutation test). However, cases had significantly higher ASE values when comparing medians by permutation test (P = 0.0027) and when using Wilcoxon test (P = 0.0094). We conclude that with the present-day technology, ASE differences between individuals and between cases and controls are too subtle to be used to assess CRC risk. More advanced technology is expected to resolve this issue as well as the low informativity caused by the limited heterozygosity of transcribed SNPs.
Carcinogenesis 10/2010; 31(10):1800-4. · 5.70 Impact Factor
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Courtney Gray-McGuire,
Kishore Guda,
Indra Adrianto,
Chee Paul Lin,
Leanna Natale,
John D Potter,
Polly Newcomb,
Elizabeth M Poole,
Cornelia M Ulrich,
Noralane Lindor, [......],
Mark Jenkins,
Joanne Young,
Daniel Buchanan,
Steve Gallinger,
Mark Adams,
Susan Lewis,
Joseph Willis,
Robert Elston, Sanford D Markowitz,
Georgia L Wiesner
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ABSTRACT: Genetic risk factors are important contributors to the development of colorectal cancer. Following the definition of a linkage signal at 9q22-31, we fine mapped this region in an independent collection of colon cancer families. We used a custom array of single-nucleotide polymorphisms (SNP) densely spaced across the candidate region, performing both single-SNP and moving-window association analyses to identify a colon neoplasia risk haplotype. Through this approach, we isolated the association effect to a five-SNP haplotype centered at 98.15 Mb on chromosome 9q. This haplotype is in strong linkage disequilibrium with the haplotype block containing HABP4 and may be a surrogate for the effect of this CD30 Ki-1 antigen. It is also in close proximity to GALNT12, also recently shown to be altered in colon tumors. We used a predictive modeling algorithm to show the contribution of this risk haplotype and surrounding candidate genes in distinguishing between colon cancer cases and healthy controls. The ability to replicate this finding, the strength of the haplotype association (odds ratio, 3.68), and the accuracy of our prediction model (approximately 60%) all strongly support the presence of a locus for familial colon cancer on chromosome 9q.
Cancer Research 07/2010; 70(13):5409-18. · 7.86 Impact Factor
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ABSTRACT: The presence of hundreds of copies of mitochondrial DNA (mtDNA) in each human cell poses a challenge for the complete characterization of mtDNA genomes by conventional sequencing technologies. Here we describe digital sequencing of mtDNA genomes with the use of massively parallel sequencing-by-synthesis approaches. Although the mtDNA of human cells is considered to be homogeneous, we found widespread heterogeneity (heteroplasmy) in the mtDNA of normal human cells. Moreover, the frequency of heteroplasmic variants varied considerably between different tissues in the same individual. In addition to the variants identified in normal tissues, cancer cells harboured further homoplasmic and heteroplasmic mutations that could also be detected in patient plasma. These studies provide insights into the nature and variability of mtDNA sequences and have implications for mitochondrial processes during embryogenesis, cancer biomarker development and forensic analysis. In particular, they demonstrate that individual humans are characterized by a complex mixture of related mitochondrial genotypes rather than a single genotype.
Nature 03/2010; 464(7288):610-4. · 36.28 Impact Factor
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Yiqing Zhao,
Xiaodong Zhang,
Kishore Guda,
Earl Lawrence,
Qun Sun,
Toshio Watanabe,
Yoichiro Iwakura,
Masahide Asano,
Lanlan Wei,
Zhirong Yang,
Weiping Zheng,
Dawn Dawson,
Joseph Willis, Sanford D Markowitz,
Masanobu Satake,
Zhenghe Wang
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ABSTRACT: Protein tyrosine phosphatase receptor-type T (PTPRT) is the most frequently mutated tyrosine phosphatase in human cancers. However, the cell signaling pathways regulated by PTPRT largely remain to be elucidated. Here, we show that paxillin is a direct substrate of PTPRT and that PTPRT specifically regulates paxillin phosphorylation at tyrosine residue 88 (Y88) in colorectal cancer (CRC) cells. We engineered CRC cells homozygous for a paxillin Y88F knock-in mutant and found that these cells exhibit significantly reduced cell migration and impaired anchorage-independent growth, fail to form xenograft tumors in nude mice, and have decreased phosphorylation of p130CAS, SHP2, and AKT. PTPRT knockout mice that we generated exhibit increased levels of colonic paxillin phosphorylation at residue Y88 and are highly susceptible to carcinogen azoxymethane-induced colon tumor, providing critical in vivo evidence that PTPRT normally functions as a tumor suppressor. Moreover, similarly increased paxillin pY88 is also found as a common feature of human colon cancers. These studies reveal an important signaling pathway that plays a critical role in colorectal tumorigenesis.
Proceedings of the National Academy of Sciences 02/2010; 107(6):2592-7. · 9.68 Impact Factor
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Zhanwen Du,
Jing Song,
Yong Wang,
Yiqing Zhao,
Kishore Guda,
Shuming Yang,
Hung-Ying Kao,
Yan Xu,
Joseph Willis, Sanford D Markowitz,
David Sedwick,
Robert M Ewing,
Zhenghe Wang
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ABSTRACT: DNA methyltransferase 1 (DNMT1) is the primary enzyme that maintains DNA methylation. We describe a previously unknown mode of regulation of DNMT1 protein stability through the coordinated action of an array of DNMT1-associated proteins. DNMT1 was destabilized by acetylation by the acetyltransferase Tip60, which triggered ubiquitination by the E3 ligase UHRF1, thereby targeting DNMT1 for proteasomal degradation. In contrast, DNMT1 was stabilized by histone deacetylase 1 (HDAC1) and the deubiquitinase HAUSP (herpes virus-associated ubiquitin-specific protease). Analysis of the abundance of DNMT1 and Tip60, as well as the association between HAUSP and DNMT1, suggested that during the cell cycle the initiation of DNMT1 degradation was coordinated with the end of DNA replication and the need for DNMT activity. In human colon cancers, the abundance of DNMT1 correlated with that of HAUSP. HAUSP knockdown rendered colon cancer cells more sensitive to killing by HDAC inhibitors both in tissue culture and in tumor xenograft models. Thus, these studies provide a mechanism-based rationale for the development of HDAC and HAUSP inhibitors for combined use in cancer therapy.
Science Signaling 01/2010; 3(146):ra80. · 7.50 Impact Factor
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New England Journal of Medicine 12/2009; 361(25):2449-60. · 53.30 Impact Factor
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Mala Mani,
Daniel E Carrasco,
Yunyu Zhang,
Kohichi Takada,
Moshe E Gatt,
Jui Dutta-Simmons,
Hiroshi Ikeda,
Felipe Diaz-Griffero,
Victor Pena-Cruz,
Monica Bertagnolli,
Lois L Myeroff, Sanford D Markowitz,
Kenneth C Anderson,
Daniel R Carrasco
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ABSTRACT: Several components of the Wnt signaling cascade have been shown to function either as tumor suppressor proteins or as oncogenes in multiple human cancers, underscoring the relevance of this pathway in oncogenesis and the need for further investigation of Wnt signaling components as potential targets for cancer therapy. Here, using expression profiling analysis as well as in vitro and in vivo functional studies, we show that the Wnt pathway component BCL9 is a novel oncogene that is aberrantly expressed in human multiple myeloma as well as colon carcinoma. We show that BCL9 enhances beta-catenin-mediated transcriptional activity regardless of the mutational status of the Wnt signaling components and increases cell proliferation, migration, invasion, and the metastatic potential of tumor cells by promoting loss of epithelial and gain of mesenchymal-like phenotype. Most importantly, BCL9 knockdown significantly increased the survival of xenograft mouse models of cancer by reducing tumor load, metastasis, and host angiogenesis through down-regulation of c-Myc, cyclin D1, CD44, and vascular endothelial growth factor expression by tumor cells. Together, these findings suggest that deregulation of BCL9 is an important contributing factor to tumor progression. The pleiotropic roles of BCL9 reported in this study underscore its value as a drug target for therapeutic intervention in several malignancies associated with aberrant Wnt signaling.
Cancer Research 10/2009; 69(19):7577-86. · 7.86 Impact Factor
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Meng Li,
Wei-Dong Chen,
Nickolas Papadopoulos,
Steven N Goodman,
Niels Christian Bjerregaard,
Søren Laurberg,
Bernard Levin,
Hartmut Juhl,
Nadir Arber,
Helen Moinova,
Kris Durkee,
Kerstin Schmidt,
Yiping He,
Frank Diehl,
Victor E Velculescu,
Shibin Zhou,
Luis A Diaz,
Kenneth W Kinzler, Sanford D Markowitz,
Bert Vogelstein
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ABSTRACT: Analysis of abnormally methylated genes is increasingly important in basic research and in the development of cancer biomarkers. We have developed methyl-BEAMing technology to enable absolute quantification of the number of methylated molecules in a sample. Individual DNA fragments are amplified and analyzed either by flow cytometry or next-generation sequencing. We demonstrate enumeration of as few as one methylated molecule in approximately 5,000 unmethylated molecules in DNA from plasma or fecal samples. Using methylated vimentin as a biomarker in plasma samples, methyl-BEAMing detected 59% of cancer cases. In early-stage colorectal cancers, this sensitivity was four times more than that obtained by assaying serum-carcinoembryonic antigen (CEA). With stool samples, methyl-BEAMing detected 41% of cancers and 45% of advanced adenomas. In addition to diagnostic and prognostic applications, this digital quantification of rare methylation events should be applicable to preclinical assessment of new epigenetic biomarkers and quantitative analyses in epigenetic research.
Nature Biotechnology 09/2009; 27(9):858-63. · 29.50 Impact Factor
