1 3865 130 JAK2 REGULATES MISMATCH REPAIR PROTEIN-MEDIATED EPIGENETIC ALTERATIONS IN RESPONSE TO OXIDATIVE DAMAGE. AT SITES OF CHRONIC INFLAMMATION EPITHELIAL CELLS UNDERGO ABERRANT DNA METHYLATION THAT CONTRIBUTES TO TUMORIGENESIS. INFLAMMATION IS ASSOCIATED WITH AN INCREASE IN REACTIVE OXYGEN SPECIES (ROS) THAT CAUSE OXIDATIVE DNA DAMAGE, WHICH HAS ALSO BEEN LINKED TO EPIGENETIC ALTERATIONS. WE PREVIOUSLY DEMONSTRATED THAT IN RESPONSE TO ROS, MISMATCH REPAIR PROTEINS MSH2 AND MSH6 RECRUIT EPIGENETIC SILENCING PROTEINS DNA METHYLTRANSFERASE 1 (DNMT1) AND POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) MEMBERS TO SITES OF DNA DAMAGE, RESULTING IN TRANSCRIPTIONAL REPRESSION OF TUMOR SUPPRESSOR GENES (TSGS). HOWEVER, IT WAS UNCLEAR WHAT SIGNAL IS UNIQUE TO ROS THAT RESULTS IN THE CHROMATIN BINDING OF MSH2 AND MSH6. HEREIN, WE DEMONSTRATE THAT IN RESPONSE TO HYDROGEN PEROXIDE (H(2) O(2) ), JAK2 LOCALIZES TO THE NUCLEUS AND INTERACTS WITH MSH2 AND MSH6. INHIBITION OR KNOCKDOWN OF JAK2 REDUCES THE H(2) O(2) -INDUCED CHROMATIN INTERACTION OF MSH2, MSH6, DNMT1, AND PRC2 MEMBERS, REDUCES H(2) O(2) -INDUCED GLOBAL INCREASE IN TRIMETHYLATION OF LYSINE 27 OF HISTONE H3 (H3K27ME3), AND ABROGATES OXIDATIVE DAMAGE-INDUCED TRANSCRIPTIONAL REPRESSION OF CANDIDATE TSGS. MOREOVER, JAK2 MRNA EXPRESSION IS ASSOCIATED WITH CPG ISLAND METHYLATOR PHENOTYPE (CIMP) STATUS IN HUMAN COLORECTAL CANCER. OUR FINDINGS PROVIDE NOVEL INSIGHT INTO THE CONNECTION BETWEEN KINASE ACTIVATION AND EPIGENETIC ALTERATIONS DURING OXIDATIVE DAMAGE AND INFLAMMATION. ENVIRON. MOL. MUTAGEN. 60:308-319, 2019. (C) 2018 WILEY PERIODICALS, INC. 2019 2 4374 57 MISMATCH REPAIR PROTEINS RECRUIT DNA METHYLTRANSFERASE 1 TO SITES OF OXIDATIVE DNA DAMAGE. AT SITES OF CHRONIC INFLAMMATION, EPITHELIAL CELLS ARE EXPOSED TO HIGH LEVELS OF REACTIVE OXYGEN SPECIES AND UNDERGO CANCER-ASSOCIATED DNA METHYLATION CHANGES, SUGGESTING THAT INFLAMMATION MAY INITIATE EPIGENETIC ALTERATIONS. PREVIOUSLY, WE DEMONSTRATED THAT OXIDATIVE DAMAGE CAUSES EPIGENETIC SILENCING PROTEINS TO BECOME PART OF A LARGE COMPLEX THAT IS LOCALIZED TO GC-RICH REGIONS OF THE GENOME, INCLUDING PROMOTER CPG ISLANDS THAT ARE EPIGENETICALLY SILENCED IN CANCER. HOWEVER, WHETHER THESE PROTEINS WERE RECRUITED DIRECTLY TO DAMAGED DNA OR DURING THE DNA REPAIR PROCESS WAS UNKNOWN. HERE WE DEMONSTRATE THAT THE MISMATCH REPAIR PROTEIN HETERODIMER MSH2-MSH6 PARTICIPATES IN THE OXIDATIVE DAMAGE-INDUCED RECRUITMENT OF DNA METHYLTRANSFERASE 1 (DNMT1) TO CHROMATIN. HYDROGEN PEROXIDE TREATMENT INDUCES THE INTERACTION OF MSH2-MSH6 WITH DNMT1, SUGGESTING THAT THE RECRUITMENT IS THROUGH A PROTEIN-PROTEIN INTERACTION. IMPORTANTLY, THE REDUCTION IN TRANSCRIPTION FOR GENES WITH CPG ISLAND-CONTAINING PROMOTERS CAUSED BY OXIDATIVE DAMAGE IS ABROGATED BY KNOCKDOWN OF MSH6 AND/OR DNMT1. OUR FINDINGS PROVIDE EVIDENCE THAT THE ROLE OF DNMT1 AT SITES OF OXIDATIVE DAMAGE IS TO REDUCE TRANSCRIPTION, POTENTIALLY PREVENTING TRANSCRIPTION FROM INTERFERING WITH THE REPAIR PROCESS. THIS STUDY UNIQUELY BRINGS TOGETHER SEVERAL FACTORS THAT ARE KNOWN TO CONTRIBUTE TO COLON CANCER, NAMELY INFLAMMATION, MISMATCH REPAIR PROTEINS, AND EPIGENETIC CHANGES. 2016 3 979 27 CHRONIC OXIDATIVE STRESS INCREASES RESISTANCE TO DOXORUBICIN-INDUCED CYTOTOXICITY IN RENAL CARCINOMA CELLS POTENTIALLY THROUGH EPIGENETIC MECHANISM. RENAL CELL CARCINOMA IS THE MOST COMMON FORM OF KIDNEY CANCER AND IS HIGHLY RESISTANT TO CHEMOTHERAPY. ALTHOUGH THE ROLE OF OXIDATIVE STRESS IN KIDNEY CANCER IS KNOWN, THE CHEMOTHERAPEUTIC RESPONSE OF CANCER CELLS ADAPTED TO CHRONIC OXIDATIVE STRESS IS NOT CLEAR. HENCE, THE EFFECT OF OXIDATIVE STRESS ON SENSITIVITY TO DOXORUBICIN-INDUCED CYTOTOXICITY WAS EVALUATED USING AN IN VITRO MODEL OF HUMAN KIDNEY CANCER CELLS ADAPTED TO CHRONIC OXIDATIVE STRESS. RESULTS OF MTT- AND ANCHORAGE-INDEPENDENT GROWTH ASSAYS AND CELL CYCLE ANALYSIS REVEALED SIGNIFICANT DECREASE IN SENSITIVITY TO DOXORUBICIN IN CAKI-1 CELLS ADAPTED TO OXIDATIVE STRESS. CHANGES IN THE EXPRESSION OF GENES INVOLVED IN DRUG TRANSPORT, CELL SURVIVAL, AND DNA REPAIR-DEPENDENT APOPTOSIS FURTHER CONFIRMED INCREASED RESISTANCE TO DOXORUBICIN-INDUCED CYTOTOXICITY IN THESE CELLS. DECREASED EXPRESSION OF MISMATCH REPAIR (MMR) GENE MSH2 IN CELLS EXPOSED TO OXIDATIVE STRESS SUGGESTS THAT LOSS OF MMR-DEPENDENT APOPTOSIS COULD BE A POTENTIAL MECHANISM FOR INCREASED RESISTANCE TO DOXORUBICIN-INDUCED CYTOTOXICITY. ADDITIONALLY, DOWNREGULATION OF HDAC1, AN INCREASE IN THE LEVEL OF HISTONE H3 ACETYLATION, AND HYPERMETHYLATION OF MSH2 PROMOTER WERE ALSO OBSERVED IN CAKI-1 CELLS ADAPTED TO CHRONIC OXIDATIVE STRESS. DNA-DEMETHYLATING AGENT 5-AZA-2DC SIGNIFICANTLY RESTORED THE EXPRESSION OF MSH2 AND DOXORUBICIN-INDUCED CYTOTOXICITY IN CAKI-1 CELLS ADAPTED TO CHRONIC OXIDATIVE STRESS, SUGGESTING THE ROLE OF DNA HYPERMETHYLATION IN INACTIVATION OF MSH2 EXPRESSION AND CONSEQUENTLY MMR-DEPENDENT APOPTOSIS IN THESE CELLS. IN SUMMARY, THIS STUDY FOR THE FIRST TIME PROVIDES DIRECT EVIDENCE FOR THE ROLE OF OXIDATIVE STRESS IN CHEMOTHERAPEUTIC RESISTANCE IN RENAL CARCINOMA CELLS POTENTIALLY THROUGH EPIGENETIC MECHANISM. 2016 4 5972 30 TET REPRESSION AND INCREASED DNMT ACTIVITY SYNERGISTICALLY INDUCE ABERRANT DNA METHYLATION. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN VARIOUS HUMAN DISORDERS, SUCH AS CANCER, NEURODEGENERATIVE DISORDERS, AND METABOLIC DISORDERS. INDUCTION OF EPIGENETIC ALTERATIONS, ESPECIALLY ABERRANT DNA METHYLATION, IS ONE OF THE MAJOR MECHANISMS, BUT HOW IT IS INDUCED IS STILL UNCLEAR. HERE, WE FOUND THAT EXPRESSION OF TET GENES, METHYLATION ERASERS, WAS DOWNREGULATED IN INFLAMED MOUSE AND HUMAN TISSUES, AND THAT THIS WAS CAUSED BY UPREGULATION OF TET-TARGETING MIRNAS SUCH AS MIR20A, MIR26B, AND MIR29C, LIKELY DUE TO ACTIVATION OF NF-KAPPAB SIGNALING DOWNSTREAM OF IL-1BETA AND TNF-ALPHA. HOWEVER, TET KNOCKDOWN INDUCED ONLY MILD ABERRANT METHYLATION. NITRIC OXIDE (NO), PRODUCED BY NOS2, ENHANCED ENZYMATIC ACTIVITY OF DNA METHYLTRANSFERASES (DNMTS), METHYLATION WRITERS, AND NO EXPOSURE INDUCED MINIMAL ABERRANT METHYLATION. IN CONTRAST, A COMBINATION OF TET KNOCKDOWN AND NO EXPOSURE SYNERGISTICALLY INDUCED ABERRANT METHYLATION, INVOLVING GENOMIC REGIONS NOT METHYLATED BY EITHER ALONE. THE RESULTS SHOWED THAT A VICIOUS COMBINATION OF TET REPRESSION, DUE TO NF-KAPPAB ACTIVATION, AND DNMT ACTIVATION, DUE TO NO PRODUCTION, IS RESPONSIBLE FOR ABERRANT METHYLATION INDUCTION IN HUMAN TISSUES. 2020 5 3658 39 INDUCTION OF ABERRANT TRIMETHYLATION OF HISTONE H3 LYSINE 27 BY INFLAMMATION IN MOUSE COLONIC EPITHELIAL CELLS. A FIELD FOR CANCERIZATION (FIELD DEFECT), WHERE GENETIC AND EPIGENETIC ALTERATIONS ARE ACCUMULATED IN NORMAL-APPEARING TISSUES, IS INVOLVED IN HUMAN CARCINOGENESIS, ESPECIALLY CANCERS ASSOCIATED WITH CHRONIC INFLAMMATION. ALTHOUGH ABERRANT DNA METHYLATION IS INVOLVED IN THE FIELD DEFECT AND INDUCED BY CHRONIC INFLAMMATION, IT IS STILL UNCLEAR FOR TRIMETHYLATION OF HISTONE H3 LYSINE 27 (H3K27ME3), WHICH IS INVOLVED IN GENE REPRESSION INDEPENDENT OF DNA METHYLATION AND FUNCTIONS AS A PRE-MARK FOR ABERRANT DNA METHYLATION. IN THIS STUDY, USING A MOUSE COLITIS MODEL INDUCED BY DEXTRAN SULFATE SODIUM (DSS), WE AIMED TO CLARIFY WHETHER ABERRANT H3K27ME3 IS INDUCED BY INFLAMMATION AND INVOLVED IN A FIELD DEFECT. CHIP-ON-CHIP ANALYSIS OF COLONIC EPITHELIAL CELLS REVEALED THAT H3K27ME3 LEVELS WERE INCREASED OR DECREASED FOR 266 GENOMIC REGIONS BY AGING, AND MORE EXTENSIVELY (23 INCREASED AND 3574 DECREASED REGIONS) BY COLITIS. SUCH INCREASE OR DECREASE OF H3K27ME3 WAS INDUCED AS EARLY AS 2 WEEKS AFTER THE INITIATION OF DSS TREATMENT, AND PERSISTED AT LEAST FOR 16 WEEKS EVEN AFTER THE INFLAMMATION DISAPPEARED. SOME OF THE ABERRANT H3K27ME3 IN COLONIC EPITHELIAL CELLS WAS CARRIED OVER INTO COLON TUMORS. FURTHERMORE, H3K27ME3 ACQUIRED AT DAPK1 BY COLITIS WAS FOLLOWED BY INCREASED DNA METHYLATION, SUPPORTING ITS FUNCTION AS A PRE-MARK FOR ABERRANT DNA METHYLATION. THESE RESULTS DEMONSTRATED THAT ABERRANT H3K27ME3 CAN BE INDUCED BY EXPOSURE TO A SPECIFIC ENVIRONMENT, SUCH AS COLITIS, AND SUGGESTED THAT ABERRANT HISTONE MODIFICATION, IN ADDITION TO ABERRANT DNA METHYLATION, IS INVOLVED IN THE FORMATION OF A FIELD DEFECT. 2012 6 3527 28 IL-6 ENHANCES THE NUCLEAR TRANSLOCATION OF DNA CYTOSINE-5-METHYLTRANSFERASE 1 (DNMT1) VIA PHOSPHORYLATION OF THE NUCLEAR LOCALIZATION SEQUENCE BY THE AKT KINASE. THE EPIGENETIC PROGRAMMING OF GENOMIC DNA IS ACCOMPLISHED, IN PART, BY SEVERAL DNA CYTOSINE-5-METHYLTRANSFERASES THAT ACT BY COVALENTLY MODIFYING CYTOSINES WITH THE ADDITION OF A METHYL GROUP. THIS COVALENT MODIFICATION IS MAINTAINED BY THE DNA CYTOSINE-5-METHYLTRANSFERASE-1 ENZYME (DNMT1), WHICH IS CAPABLE OF ACTING IN CONCERT WITH OTHER SIMILAR ENZYMES TO SILENCE IMPORTANT TUMOR SUPPRESSOR GENES. IL-6 IS A MULTIFUNCTIONAL MEDIATOR OF INFLAMMATION, ACTING THROUGH SEVERAL MAJOR SIGNALING CASCADES, INCLUDING THE PHOSPHATIDYLINOSITOL-3-KINASE PATHWAY (PI-3-K), WHICH ACTIVATES PROTEIN KINASE B (AKT/PKB) DOWNSTREAM. HERE, WE SHOW THAT THE SUBCELLULAR LOCALIZATION OF DNMT1 CAN BE ALTERED BY THE ADDITION OF IL-6, INCREASING THE RATE OF NUCLEAR TRANSLOCATION OF THE ENZYME FROM THE CYTOSOLIC COMPARTMENT. THE MECHANISM OF NUCLEAR TRANSLOCATION OF DNMT1 IS GREATLY ENHANCED BY PHOSPHORYLATION OF THE DNMT1 NUCLEAR LOCALIZATION SIGNAL (NLS) BY PKB/AKT KINASE. MUTAGENIC ALTERATION OF THE TWO AKT TARGET AMINO ACIDS WITHIN THE NLS RESULTS IN A MAJOR LOSS OF DNMT1 NUCLEAR TRANSLOCATION, WHILE THE CREATION OF A "PHOSPHO-MIMIC" AMINO ACID (MUTATION TO ACIDIC RESIDUES) RESTORES THIS COMPARTMENTATION ABILITY. THESE OBSERVATIONS SUGGEST AN INTERESTING HYPOTHESIS REGARDING HOW MEDIATORS OF CHRONIC INFLAMMATION MAY DISTURB THE DELICATE BALANCE OF CELLULAR COMPARTMENTALIZATION OF IMPORTANT PROTEINS, AND REVEALS A POTENTIAL MECHANISM FOR THE INDUCTION OR ENHANCEMENT OF TUMOR GROWTH VIA ALTERATION OF THE COMPONENTS INVOLVED IN THE EPIGENETIC PROGRAMMING OF A CELL. 2007 7 4497 39 MORPHINE LEADS TO GLOBAL GENOME CHANGES IN H3K27ME3 LEVELS VIA A POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) SELF-REGULATORY MECHANISM IN MESCS. BACKGROUND: ENVIRONMENTALLY INDUCED EPIGENETIC CHANGES CAN LEAD TO HEALTH PROBLEMS OR DISEASE, BUT THE MECHANISMS INVOLVED REMAIN UNCLEAR. MORPHINE CAN PASS THROUGH THE PLACENTAL BARRIER LEADING TO ABNORMAL EMBRYO DEVELOPMENT. HOWEVER, THE MECHANISM BY WHICH MORPHINE CAUSES THESE EFFECTS AND HOW THEY SOMETIMES PERSIST INTO ADULTHOOD IS NOT WELL KNOWN. TO UNRAVEL THE MORPHINE-INDUCED CHROMATIN ALTERATIONS INVOLVED IN ABERRANT EMBRYO DEVELOPMENT, WE EXPLORED THE ROLE OF THE H3K27ME3/PRC2 REPRESSIVE COMPLEX IN GENE EXPRESSION AND ITS TRANSMISSION ACROSS CELLULAR GENERATIONS IN RESPONSE TO MORPHINE. RESULTS: USING MOUSE EMBRYONIC STEM CELLS AS A MODEL SYSTEM, WE FOUND THAT CHRONIC MORPHINE TREATMENT INDUCES A GLOBAL DOWNREGULATION OF THE HISTONE MODIFICATION H3K27ME3. CONVERSELY, CHIP-SEQ SHOWED A REMARKABLE INCREASE IN H3K27ME3 LEVELS AT SPECIFIC GENOMIC SITES, PARTICULARLY PROMOTERS, DISRUPTING SELECTIVE TARGET GENES RELATED TO EMBRYO DEVELOPMENT, CELL CYCLE AND METABOLISM. THROUGH A SELF-REGULATORY MECHANISM, MORPHINE DOWNREGULATED THE TRANSCRIPTION OF PRC2 COMPONENTS RESPONSIBLE FOR H3K27ME3 BY ENRICHING HIGH H3K27ME3 LEVELS AT THE PROMOTER REGION. DOWNREGULATION OF PRC2 COMPONENTS PERSISTED FOR AT LEAST 48 H (4 CELL CYCLES) FOLLOWING MORPHINE REMOVAL, THOUGH PROMOTER H3K27ME3 LEVELS RETURNED TO CONTROL LEVELS. CONCLUSIONS: MORPHINE INDUCES TARGETING OF THE PRC2 COMPLEX TO SELECTED PROMOTERS, INCLUDING THOSE OF PRC2 COMPONENTS, LEADING TO CHARACTERISTIC CHANGES IN GENE EXPRESSION AND A GLOBAL REDUCTION IN H3K27ME3. FOLLOWING MORPHINE REMOVAL, ENHANCED PROMOTER H3K27ME3 LEVELS REVERT TO NORMAL SOONER THAN GLOBAL H3K27ME3 OR PRC2 COMPONENT TRANSCRIPT LEVELS. WE SUGGEST THAT H3K27ME3 IS INVOLVED IN INITIATING MORPHINE-INDUCED CHANGES IN GENE EXPRESSION, BUT NOT IN THEIR MAINTENANCE. MODEL OF POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) AND H3K27ME3 ALTERATIONS INDUCED BY CHRONIC MORPHINE EXPOSURE. MORPHINE INDUCES H3K27ME3 ENRICHMENT AT PROMOTERS OF GENES ENCODING CORE MEMBERS OF THE PRC2 COMPLEX AND IS ASSOCIATED WITH THEIR TRANSCRIPTIONAL DOWNREGULATION. 2020 8 1656 42 DOUBLE STRAND BREAKS CAN INITIATE GENE SILENCING AND SIRT1-DEPENDENT ONSET OF DNA METHYLATION IN AN EXOGENOUS PROMOTER CPG ISLAND. CHRONIC EXPOSURE TO INDUCERS OF DNA BASE OXIDATION AND SINGLE AND DOUBLE STRAND BREAKS CONTRIBUTE TO TUMORIGENESIS. IN ADDITION TO THE GENETIC CHANGES CAUSED BY THIS DNA DAMAGE, SUCH TUMORS OFTEN CONTAIN EPIGENETICALLY SILENCED GENES WITH ABERRANT PROMOTER REGION CPG ISLAND DNA HYPERMETHYLATION. WE HEREIN EXPLORE THE RELATIONSHIPS BETWEEN SUCH DNA DAMAGE AND EPIGENETIC GENE SILENCING USING AN EXPERIMENTAL MODEL IN WHICH WE INDUCE A DEFINED DOUBLE STRAND BREAK IN AN EXOGENOUS PROMOTER CONSTRUCT OF THE E-CADHERIN CPG ISLAND, WHICH IS FREQUENTLY ABERRANTLY DNA HYPERMETHYLATED IN EPITHELIAL CANCERS. FOLLOWING THE ONSET OF REPAIR OF THE BREAK, WE OBSERVE RECRUITMENT TO THE SITE OF DAMAGE OF KEY PROTEINS INVOLVED IN ESTABLISHING AND MAINTAINING TRANSCRIPTIONAL REPRESSION, NAMELY SIRT1, EZH2, DNMT1, AND DNMT3B, AND THE APPEARANCE OF THE SILENCING HISTONE MODIFICATIONS, HYPOACETYL H4K16, H3K9ME2 AND ME3, AND H3K27ME3. ALTHOUGH IN MOST CELLS SELECTED AFTER THE BREAK, DNA REPAIR OCCURS FAITHFULLY WITH PRESERVATION OF ACTIVITY OF THE PROMOTER, A SMALL PERCENTAGE OF THE PLATED CELLS DEMONSTRATE INDUCTION OF HERITABLE SILENCING. THE CHROMATIN AROUND THE BREAK SITE IN SUCH A SILENT CLONE IS ENRICHED FOR MOST OF THE ABOVE SILENT CHROMATIN PROTEINS AND HISTONE MARKS, AND THE REGION HARBORS THE APPEARANCE OF INCREASING DNA METHYLATION IN THE CPG ISLAND OF THE PROMOTER. DURING THE ACUTE BREAK, SIRT1 APPEARS TO BE REQUIRED FOR THE TRANSIENT RECRUITMENT OF DNMT3B AND SUBSEQUENT METHYLATION OF THE PROMOTER IN THE SILENT CLONES. TAKEN TOGETHER, OUR DATA SUGGEST THAT NORMAL REPAIR OF A DNA BREAK CAN OCCASIONALLY CAUSE HERITABLE SILENCING OF A CPG ISLAND-CONTAINING PROMOTER BY RECRUITMENT OF PROTEINS INVOLVED IN SILENCING. FURTHERMORE, WITH CONTRIBUTION OF THE STRESS-RELATED PROTEIN SIRT1, THE BREAK CAN LEAD TO THE ONSET OF ABERRANT CPG ISLAND DNA METHYLATION, WHICH IS FREQUENTLY ASSOCIATED WITH TIGHT GENE SILENCING IN CANCER. 2008 9 6661 38 UPREGULATION OF DNA METHYLTRANSFERASE-MEDIATED GENE SILENCING, ANCHORAGE-INDEPENDENT GROWTH, AND MIGRATION OF COLON CANCER CELLS BY INTERLEUKIN-6. INFLAMMATORY BOWEL DISEASE IS CHARACTERIZED BY CHRONIC INFLAMMATION WHICH PREDISPOSES TO COLORECTAL CANCER. THE MECHANISMS BY WHICH INFLAMMATION PROMOTES TUMORIGENESIS ARE NOT FULLY KNOWN. WE AIMED TO INVESTIGATE THE LINKS BETWEEN COLONIC INFLAMMATION AND TUMORIGENESIS VIA EPIGENETIC GENE SILENCING. COLON CANCER SPECIMENS WERE ASSESSED FOR THE EXPRESSION OF DNA METHYLTRANSFERASE-1 (DNMT-1) USING IMMUNOHISTOCHEMISTRY. COLORECTAL CARCINOMA CELL LINES WERE ASSESSED FOR DNMT1 EXPRESSION, METHYLCYTOSINE CONTENT, PROMOTER METHYLATION, GENE EXPRESSION, AND TUMORIGENESIS IN RESPONSE TO INTERLEUKIN (IL)-6. DNMT1 WAS EXPRESSED AT HIGHER LEVELS IN BOTH THE PERITUMORAL STROMA AND TUMOR IN INFLAMMATORY BOWEL DISEASE-ASSOCIATED CANCERS COMPARED WITH SPORADIC COLON CANCERS. IL-6 TREATMENT OF COLON CANCER CELLS RESULTED IN AN INCREASE IN DNMT1 EXPRESSION, INDEPENDENT OF DE NOVO GENE EXPRESSION. IL-6 INCREASED THE METHYLATION OF PROMOTER REGIONS OF GENES ASSOCIATED WITH TUMOR SUPPRESSION, ADHESION, AND APOPTOSIS RESISTANCE. EXPRESSION OF A SUBSET OF THESE GENES WAS DOWNREGULATED BY IL-6, AN EFFECT THAT WAS PREVENTED BY PREINCUBATION WITH 5-AZADEOXYCYTIDINE, A DNMT1 INHIBITOR. ANCHORAGE-INDEPENDENT GROWTH AND MIGRATION OF COLON CANCER CELLS WAS ALSO INCREASED BY IL-6 IN A 5-AZADEOXYCYTIDINE-SENSITIVE MANNER. OUR RESULTS INDICATE THAT DNMT-MEDIATED GENE SILENCING MAY PLAY A ROLE IN INFLAMMATION-ASSOCIATED COLON TUMORIGENESIS. 2010 10 6176 34 THE HISTONE H3 LYSINE-27 DEMETHYLASE JMJD3 LINKS INFLAMMATION TO INHIBITION OF POLYCOMB-MEDIATED GENE SILENCING. EPIGENETIC CHROMATIN MARKS RESTRICT THE ABILITY OF DIFFERENTIATED CELLS TO CHANGE GENE EXPRESSION PROGRAMS IN RESPONSE TO ENVIRONMENTAL CUES AND TO TRANSDIFFERENTIATE. POLYCOMB GROUP (PCG) PROTEINS MEDIATE GENE SILENCING AND REPRESS TRANSDIFFERENTIATION IN A MANNER DEPENDENT ON HISTONE H3 LYSINE 27 TRIMETHYLATION (H3K27ME3). HOWEVER, MACROPHAGES MIGRATED INTO INFLAMED TISSUES CAN TRANSDIFFERENTIATE, BUT IT IS UNKNOWN WHETHER INFLAMMATION ALTERS PCG-DEPENDENT SILENCING. HERE WE SHOW THAT THE JMJC-DOMAIN PROTEIN JMJD3 IS A H3K27ME DEMETHYLASE EXPRESSED IN MACROPHAGES IN RESPONSE TO BACTERIAL PRODUCTS AND INFLAMMATORY CYTOKINES. JMJD3 BINDS PCG TARGET GENES AND REGULATES THEIR H3K27ME3 LEVELS AND TRANSCRIPTIONAL ACTIVITY. THE DISCOVERY OF AN INDUCIBLE ENZYME THAT ERASES A HISTONE MARK CONTROLLING DIFFERENTIATION AND CELL IDENTITY PROVIDES A LINK BETWEEN INFLAMMATION AND REPROGRAMMING OF THE EPIGENOME, WHICH COULD BE THE BASIS FOR MACROPHAGE PLASTICITY AND MIGHT EXPLAIN THE DIFFERENTIATION ABNORMALITIES IN CHRONIC INFLAMMATION. 2007 11 2055 34 EPIGENETIC CONTROL DURING LYMPHOID DEVELOPMENT AND IMMUNE RESPONSES: ABERRANT REGULATION, VIRUSES, AND CANCER. METHYLATION OF CYTOSINES CONTROLS A NUMBER OF BIOLOGIC PROCESSES SUCH AS IMPRINTING AND X CHROMOSOMAL INACTIVATION. DNA HYPERMETHYLATION IS CLOSELY ASSOCIATED WITH TRANSCRIPTIONAL SILENCING, WHILE DNA HYPOMETHYLATION IS ASSOCIATED WITH TRANSCRIPTIONAL ACTIVATION. HYPOACETYLATION OF HISTONES LEADS TO COMPACT CHROMATIN WITH REDUCED ACCESSIBILITY TO THE TRANSCRIPTIONAL MACHINERY. METHYL-CPG BINDING PROTEINS CAN RECRUIT COREPRESSORS AND HISTONE DEACETYLASES; THUS, THE INTERPLAY BETWEEN THESE EPIGENETIC MECHANISMS REGULATES GENE ACTIVATION. METHYLATION HAS BEEN IMPLICATED AS AN IMPORTANT MECHANISM DURING IMMUNE DEVELOPMENT, CONTROLLING VDJ RECOMBINATION, LINEAGE-SPECIFIC EXPRESSION OF CELL SURFACE ANTIGENS, AND TRANSCRIPTIONAL REGULATION OF CYTOKINE GENES DURING IMMUNE RESPONSES. ABERRATIONS IN EPIGENETIC MACHINERY, EITHER BY GENETIC MUTATIONS OR BY SOMATIC CHANGES SUCH AS VIRAL INFECTIONS, ARE ASSOCIATED WITH EARLY ALTERATIONS IN CHRONIC DISEASES SUCH AS IMMUNODEFICIENCY AND CANCER. 2003 12 2926 25 GENERATION OF AN EPIGENETIC SIGNATURE BY CHRONIC HYPOXIA IN PROSTATE CELLS. INCREASING LEVELS OF TISSUE HYPOXIA HAVE BEEN REPORTED AS A NATURAL FEATURE OF THE AGING PROSTATE GLAND AND MAY BE A RISK FACTOR FOR THE DEVELOPMENT OF PROSTATE CANCER. IN THIS STUDY, WE HAVE USED PWR-1E BENIGN PROSTATE EPITHELIAL CELLS AND AN EQUIVALENTLY AGED HYPOXIA-ADAPTED PWR-1E SUB-LINE TO IDENTIFY PHENOTYPIC AND EPIGENETIC CONSEQUENCES OF CHRONIC HYPOXIA IN PROSTATE CELLS. WE HAVE IDENTIFIED A SIGNIFICANTLY ALTERED CELLULAR PHENOTYPE IN RESPONSE TO CHRONIC HYPOXIA AS CHARACTERIZED BY INCREASED RECEPTOR-MEDIATED APOPTOTIC RESISTANCE, THE INDUCTION OF CELLULAR SENESCENCE, INCREASED INVASION AND THE INCREASED SECRETION OF IL-1 BETA, IL6, IL8 AND TNFALPHA CYTOKINES. IN ASSOCIATION WITH THESE PHENOTYPIC CHANGES AND THE ABSENCE OF HIF-1 ALPHA PROTEIN EXPRESSION, WE HAVE DEMONSTRATED SIGNIFICANT INCREASES IN GLOBAL LEVELS OF DNA METHYLATION AND H3K9 HISTONE ACETYLATION IN THESE CELLS, CONCOMITANT WITH THE INCREASED EXPRESSION OF DNA METHYLTRANSFERASE DMNT3B AND GENE-SPECIFIC CHANGES IN DNA METHYLATION AT KEY IMPRINTING LOCI. IN CONCLUSION, WE HAVE DEMONSTRATED A GENOME-WIDE ADJUSTMENT OF DNA METHYLATION AND HISTONE ACETYLATION UNDER CHRONIC HYPOXIC CONDITIONS IN THE PROSTATE. THESE EPIGENETIC SIGNATURES MAY REPRESENT AN ADDITIONAL MECHANISM TO PROMOTE AND MAINTAIN A HYPOXIC-ADAPTED CELLULAR PHENOTYPE WITH A POTENTIAL ROLE IN TUMOUR DEVELOPMENT. 2009 13 1615 28 DNA METHYLTRANSFERASE 3B PLAYS A PROTECTIVE ROLE AGAINST HEPATOCARCINOGENESIS CAUSED BY CHRONIC INFLAMMATION VIA MAINTAINING MITOCHONDRIAL HOMEOSTASIS. MOST HEPATOCELLULAR CARCINOMAS (HCCS) DEVELOP ON THE BASIS OF CHRONIC HEPATITIS, BUT THE MECHANISM OF EPIGENETIC REGULATION IN INFLAMMATORY HEPATOCARCINOGENESIS HAS YET TO BE ELUCIDATED. AMONG DE NOVO DNA METHYLTRANSFERASES (DNMTS), DNMT3B HAS LATELY BEEN REPORTED TO ACT SPECIFICALLY ON ACTIVELY TRANSCRIBED GENES, SUGGESTING THE POSSIBILITY THAT IT PLAYS A ROLE IN THE PATHOGENESIS OF CANCER. WE CONFIRMED THAT DNMT3B ISOFORMS LACKING ITS CATALYTIC DOMAIN WERE HIGHLY EXPRESSED IN HCCS COMPARED WITH NON-TUMOROUS LIVER TISSUE. TO ELUCIDATE THE ROLE OF DNMT3B IN HEPATOCARCINOGENESIS, WE GENERATED A GENETICALLY ENGINEERED MOUSE MODEL WITH HEPATOCYTE-SPECIFIC DNMT3B DELETION. THE LIVER OF THE DNMT3B-DEFICIENT MICE EXHIBITED AN EXACERBATION OF THIOACETAMIDE-INDUCED HEPATITIS, PROGRESSION OF LIVER FIBROSIS AND A HIGHER INCIDENCE OF HCC COMPARED WITH THE LIVER OF THE CONTROL MICE. WHOLE-GENOME BISULFITE SEQUENCING VERIFIED A LOWER CG METHYLATION LEVEL IN THE DNMT3B-DEFICIENT LIVER, DEMONSTRATING DIFFERENTIALLY METHYLATED REGIONS THROUGHOUT THE GENOME. TRANSCRIPTOME ANALYSIS REVEALED DECREASED EXPRESSION OF GENES RELATED TO OXIDATIVE PHOSPHORYLATION IN THE DNMT3B-DEFICIENT LIVER. MOREOVER, PRIMARY HEPATOCYTES ISOLATED FROM THE DNMT3B-DEFICIENT MICE SHOWED REDUCED MITOCHONDRIAL RESPIRATORY CAPACITY, LEADING TO THE ENHANCEMENT OF OXIDATIVE STRESS IN THE LIVER TISSUE. OUR FINDINGS SUGGEST THE PROTECTIVE ROLE OF DNMT3B AGAINST CHRONIC INFLAMMATION AND HCC DEVELOPMENT VIA MAINTAINING MITOCHONDRIAL HOMEOSTASIS. 2020 14 1117 29 COMPARATIVE AND EXPERIMENTAL STUDIES ON THE GENES ALTERED BY CHRONIC HYPOXIA IN HUMAN BRAIN MICROENDOTHELIAL CELLS. BACKGROUND : HYPOXIA INDUCIBLE FACTOR 1 ALPHA (HIF1A) IS A MASTER REGULATOR OF ACUTE HYPOXIA; HOWEVER, WITH CHRONIC HYPOXIA, HIF1A LEVELS RETURN TO THE NORMOXIC LEVELS. IMPORTANTLY, THE GENES THAT ARE INVOLVED IN THE CELL SURVIVAL AND VIABILITY UNDER CHRONIC HYPOXIA ARE NOT KNOWN. THEREFORE, WE TESTED THE HYPOTHESIS THAT CHRONIC HYPOXIA LEADS TO THE UPREGULATION OF A CORE GROUP OF GENES WITH ASSOCIATED CHANGES IN THE PROMOTER DNA METHYLATION THAT MEDIATES THE CELL SURVIVAL UNDER HYPOXIA. RESULTS : WE EXAMINED THE EFFECT OF CHRONIC HYPOXIA (3 DAYS; 0.5% OXYGEN) ON HUMAN BRAIN MICRO ENDOTHELIAL CELLS (HBMEC) VIABILITY AND APOPTOSIS. HYPOXIA CAUSED A SIGNIFICANT REDUCTION IN CELL VIABILITY AND AN INCREASE IN APOPTOSIS. NEXT, WE EXAMINED CHRONIC HYPOXIA ASSOCIATED CHANGES IN TRANSCRIPTOME AND GENOME-WIDE PROMOTER METHYLATION. THE DATA OBTAINED WAS COMPARED WITH 16 OTHER MICROARRAY STUDIES ON CHRONIC HYPOXIA. NINE GENES WERE ALTERED IN RESPONSE TO CHRONIC HYPOXIA IN ALL 17 STUDIES. INTERESTINGLY, HIF1A WAS NOT ALTERED WITH CHRONIC HYPOXIA IN ANY OF THE STUDIES. FURTHERMORE, WE COMPARED OUR DATA TO THREE OTHER STUDIES THAT IDENTIFIED HIF-RESPONSIVE GENES BY VARIOUS APPROACHES. ONLY TWO GENES WERE FOUND TO BE HIF DEPENDENT. WE SILENCED EACH OF THESE 9 GENES USING CRISPR/CAS9 SYSTEM. DOWNREGULATION OF EGLN3 SIGNIFICANTLY INCREASED THE CELL DEATH UNDER CHRONIC HYPOXIA, WHEREAS DOWNREGULATION OF ERO1L, ENO2, ADRENOMEDULLIN, AND SPAG4 REDUCED THE CELL DEATH UNDER HYPOXIA. CONCLUSIONS : WE PROVIDE A CORE GROUP OF GENES THAT REGULATES CELLULAR ACCLIMATIZATION UNDER CHRONIC HYPOXIC STRESS, AND MOST OF THEM ARE HIF INDEPENDENT. 2017 15 3795 32 INTERLEUKIN-6 CONTRIBUTES TO GROWTH IN CHOLANGIOCARCINOMA CELLS BY ABERRANT PROMOTER METHYLATION AND GENE EXPRESSION. THE ASSOCIATION BETWEEN CHRONIC INFLAMMATION AND THE DEVELOPMENT AND PROGRESSION OF MALIGNANCY IS EXEMPLIFIED IN THE BILIARY TRACT WHERE PERSISTENT INFLAMMATION STRONGLY PREDISPOSES TO CHOLANGIOCARCINOMA. THE INFLAMMATORY CYTOKINE INTERLEUKIN-6 (IL-6) ENHANCES TUMOR GROWTH IN CHOLANGIOCARCINOMA BY ALTERED GENE EXPRESSION VIA AUTOCRINE MECHANISMS. IL-6 CAN REGULATE THE ACTIVITY OF DNA METHYLTRANSFERASES, AND MOREOVER, ABERRANT DNA METHYLATION CAN CONTRIBUTE TO CARCINOGENESIS. WE THEREFORE INVESTIGATED THE EFFECT OF CHRONIC EXPOSURE TO IL-6 ON METHYLATION-DEPENDENT GENE EXPRESSION AND TRANSFORMED CELL GROWTH IN HUMAN CHOLANGIOCARCINOMA. THE RELATIONSHIP BETWEEN AUTOCRINE IL-6 PATHWAYS, DNA METHYLATION, AND TRANSFORMED CELL GROWTH WAS ASSESSED USING MALIGNANT CHOLANGIOCYTES STABLY TRANSFECTED TO OVEREXPRESS IL-6. TREATMENT WITH THE DNA METHYLATION INHIBITOR 5-AZA-2'-DEOXYCYTIDINE DECREASED CELL PROLIFERATION, GROWTH IN SOFT AGAR, AND METHYLCYTOSINE CONTENT OF MALIGNANT CHOLANGIOCYTES. HOWEVER, THIS EFFECT WAS NOT OBSERVED IN IL-6-OVEREXPRESSING CELLS. IL-6 OVEREXPRESSION RESULTED IN THE ALTERED EXPRESSION AND PROMOTER METHYLATION OF SEVERAL GENES, INCLUDING THE EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR). EGFR PROMOTER METHYLATION WAS DECREASED AND GENE AND PROTEIN EXPRESSION WAS INCREASED BY IL-6. THUS, EPIGENETIC REGULATION OF GENE EXPRESSION BY IL-6 CAN CONTRIBUTE TO TUMOR PROGRESSION BY ALTERING PROMOTER METHYLATION AND GENE EXPRESSION OF GROWTH-REGULATORY PATHWAYS, SUCH AS THOSE INVOLVING EGFR. MOREOVER, ENHANCED IL-6 EXPRESSION MAY DECREASE THE SENSITIVITY OF TUMOR CELLS TO THERAPEUTIC TREATMENTS USING METHYLATION INHIBITORS. THESE OBSERVATIONS HAVE IMPORTANT IMPLICATIONS FOR CANCER TREATMENT AND PROVIDE A MECHANISM BY WHICH PERSISTENT CYTOKINE STIMULATION CAN PROMOTE TUMOR GROWTH. 2006 16 3791 38 INTERLEUKIN 6 SUPPORTS THE MAINTENANCE OF P53 TUMOR SUPPRESSOR GENE PROMOTER METHYLATION. A STRONG ASSOCIATION EXISTS BETWEEN STATES OF CHRONIC INFLAMMATION AND CANCER, AND IT IS BELIEVED THAT MEDIATORS OF INFLAMMATION MAY BE RESPONSIBLE FOR THIS PHENOMENON. INTERLEUKIN 6 (IL-6) IS AN INFLAMMATORY CYTOKINE KNOWN TO PLAY A ROLE IN THE GROWTH AND SURVIVAL OF MANY TYPES OF TUMORS, YET THE MECHANISMS EMPLOYED BY THIS PLEOMORPHIC CYTOKINE TO ACCOMPLISH THIS FEAT ARE STILL POORLY UNDERSTOOD. ANOTHER IMPORTANT FACTOR IN TUMOR DEVELOPMENT SEEMS TO BE THE HYPERMETHYLATION OF CPG ISLANDS LOCATED WITHIN THE PROMOTER REGIONS OF TUMOR SUPPRESSOR GENES. THIS COMMON EPIGENETIC ALTERATION ENABLES TUMOR CELLS TO REDUCE OR INACTIVATE THE EXPRESSION OF IMPORTANT TUMOR SUPPRESSOR AND CELL CYCLE REGULATORY GENES. HERE WE SHOW THAT IN THE IL-6-RESPONSIVE HUMAN MULTIPLE MYELOMA CELL LINE KAS 6/1, THE PROMOTER REGION OF P53 IS EPIGENETICALLY MODIFIED BY METHYLTRANSFERASES, RESULTING IN DECREASED LEVELS OF EXPRESSION. FURTHERMORE, CELLS TREATED WITH IL-6 EXHIBIT AN INCREASE IN THE EXPRESSION OF THE DNA MAINTENANCE METHYLATION ENZYME, DNMT-1. THE DNA METHYLTRANSFERASE INHIBITOR ZEBULARINE REVERSES THE METHYLATION OF THE P53 PROMOTER, ALLOWING THE RESUMPTION OF ITS EXPRESSION. HOWEVER, WHEN ZEBULARINE IS WITHDRAWN FROM THE CELLS, THE REESTABLISHMENT OF THE ORIGINAL CPG ISLAND METHYLATION WITHIN THE P53 PROMOTER DOES NOT OCCUR IN THE ABSENCE OF IL-6, AND CELLS WHICH DO NOT RECEIVE IL-6 EVENTUALLY DIE, AS P53 EXPRESSION CONTINUES UNCHECKED BY REMETHYLATION. INTERESTINGLY, THIS LOSS OF VIABILITY SEEMS TO INVOLVE NOT THE WITHDRAWAL OF CYTOKINE, BUT THE INABILITY OF THE CELL TO RESILENCE THE PROMOTER. CONSISTENT WITH THIS MODEL, WHEN CELLS THAT EXPRESS IL-6 IN AN AUTOCRINE FASHION ARE SUBJECTED TO IDENTICAL TREATMENT, P53 EXPRESSION IS REDUCED SHORTLY AFTER WITHDRAWAL OF ZEBULARINE. THEREFORE, IT SEEMS IL-6 IS CAPABLE OF MAINTAINING PROMOTER METHYLATION THUS REPRESENTING ONE OF THE POSSIBLE MECHANISMS USED BY INFLAMMATORY MEDIATORS IN THE GROWTH AND SURVIVAL OF TUMORS. 2005 17 978 31 CHRONIC OXIDATIVE STRESS CAUSES ESTROGEN-INDEPENDENT AGGRESSIVE PHENOTYPE, AND EPIGENETIC INACTIVATION OF ESTROGEN RECEPTOR ALPHA IN MCF-7 BREAST CANCER CELLS. THE ROLE OF CHRONIC OXIDATIVE STRESS IN THE DEVELOPMENT AND AGGRESSIVE GROWTH OF ESTROGEN RECEPTOR (ER)-POSITIVE BREAST CANCER IS WELL KNOWN; HOWEVER, THE MECHANISTIC UNDERSTANDING IS NOT CLEAR. ESTROGEN-INDEPENDENT GROWTH IS ONE OF THE FEATURES OF AGGRESSIVE SUBTYPE OF BREAST CANCER. THEREFORE, THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE THE EFFECT OF OXIDATIVE STRESS ON ESTROGEN SENSITIVITY AND EXPRESSION OF NUCLEAR ESTROGEN RECEPTORS IN ER-POSITIVE BREAST CANCER CELLS. MCF-7 CELLS CHRONICALLY EXPOSED TO HYDROGEN PEROXIDE WERE USED AS A CELL MODEL IN THIS STUDY, AND THEIR GROWTH IN RESPONSE TO 17-BETA ESTRADIOL WAS EVALUATED BY CELL VIABILITY, CELL CYCLE, AND CELL MIGRATION ANALYSIS. RESULTS WERE FURTHER CONFIRMED AT MOLECULAR LEVEL BY ANALYSIS OF GENE EXPRESSIONS AT TRANSCRIPT AND PROTEIN LEVELS. HISTONE H3 MODIFICATIONS, EXPRESSION OF EPIGENETIC REGULATORY GENES, AND THE EFFECT OF DNA DEMETHYLATION WERE ALSO ANALYZED. LOSS OF GROWTH IN RESPONSE TO ESTROGEN WITH A DECREASE IN ERALPHA EXPRESSION WAS OBSERVED IN MCF-7 CELLS ADAPTED TO CHRONIC OXIDATIVE STRESS. INCREASES IN MTTFA AND NRF1 IN THESE CELLS FURTHER SUGGESTED THE ROLE OF MITOCHONDRIA-DEPENDENT REDOX-SENSITIVE GROWTH SIGNALING AS AN ALTERNATIVE PATHWAY TO ESTROGEN-DEPENDENT GROWTH. CHANGES IN EXPRESSION OF EPIGENETIC REGULATORY GENES, LEVELS OF HISTONE H3 MODIFICATIONS AS WELL AS SIGNIFICANT RESTORATIONS OF BOTH ERALPHA EXPRESSION AND ESTROGEN RESPONSE BY 5-AZA-2'-DEOXYCYTIDINE FURTHER CONFIRMED THE EPIGENETIC BASIS FOR ESTROGEN-INDEPENDENT GROWTH IN THESE CELLS. IN CONCLUSION, RESULTS OF THIS STUDY SUGGEST THAT CHRONIC OXIDATIVE STRESS CAN CONVERT ESTROGEN-DEPENDENT NONAGGRESSIVE BREAST CANCER CELLS INTO ESTROGEN-INDEPENDENT AGGRESSIVE FORM POTENTIALLY BY EPIGENETIC MECHANISM. 2015 18 4900 36 OXIDATIVE STRESS-INDUCED EPIGENETIC CHANGES ASSOCIATED WITH MALIGNANT TRANSFORMATION OF HUMAN KIDNEY EPITHELIAL CELLS. RENAL CELL CARCINOMA (RCC) IN HUMANS IS POSITIVELY INFLUENCED BY OXIDATIVE STRESS STATUS IN KIDNEYS. WE RECENTLY REPORTED THAT ADAPTIVE RESPONSE TO LOW LEVEL OF CHRONIC OXIDATIVE STRESS INDUCES MALIGNANT TRANSFORMATION OF IMMORTALIZED HUMAN RENAL TUBULAR EPITHELIAL CELLS. EPIGENETIC ALTERATIONS IN HUMAN RCC ARE WELL DOCUMENTED, BUT ITS ROLE IN OXIDATIVE STRESS-INDUCED MALIGNANT TRANSFORMATION OF KIDNEY CELLS IS NOT KNOWN. THEREFORE, THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE THE POTENTIAL ROLE OF EPIGENETIC CHANGES IN CHRONIC OXIDATIVE STRESS-INDUCED MALIGNANT TRANSFORMATION OF HK-2, HUMAN RENAL TUBULAR EPITHELIAL CELLS. THE RESULTS REVEALED ABERRANT EXPRESSION OF EPIGENETIC REGULATORY GENES INVOLVED IN DNA METHYLATION (DNMT1, DNMT3A AND MBD4) AND HISTONE MODIFICATIONS (HDAC1, HMT1 AND HAT1) IN HK-2 CELLS MALIGNANTLY TRANSFORMED BY CHRONIC OXIDATIVE STRESS. ADDITIONALLY, BOTH IN VITRO SOFT AGAR ASSAY AND IN VIVO NUDE MICE STUDY SHOWING DECREASED TUMORIGENIC POTENTIAL OF MALIGNANTLY TRANSFORMED HK-2 CELLS FOLLOWING TREATMENT WITH DNA DE-METHYLATING AGENT 5-AZA 2' DC FURTHER CONFIRMED THE CRUCIAL ROLE OF DNA HYPERMETHYALTION IN OXIDATIVE STRESS-INDUCED MALIGNANT TRANSFORMATION. CHANGES OBSERVED IN GLOBAL HISTONE H3 ACETYLATION (H3K9, H3K18, H3K27 AND H3K14) AND DECREASE IN PHOSPHO-H2AX (SER139) ALSO SUGGEST POTENTIAL ROLE OF HISTONE MODIFICATIONS IN INCREASED SURVIVAL AND MALIGNANT TRANSFORMATION OF HK-2 CELLS BY OXIDATIVE STRESS. IN SUMMARY, THE RESULTS OF THIS STUDY SUGGEST THAT EPIGENETIC REPROGRAMMING INDUCED BY LOW LEVELS OF OXIDATIVE STRESS ACT AS DRIVER FOR MALIGNANT TRANSFORMATION OF KIDNEY EPITHELIAL CELLS. FINDINGS OF THIS STUDY ARE HIGHLY RELEVANT IN POTENTIAL CLINICAL APPLICATION OF EPIGENETIC-BASED THERAPEUTICS FOR TREATMENTS OF KIDNEY CANCERS. 2017 19 2025 33 EPIGENETIC CHANGES DURING DISEASE PROGRESSION IN A MURINE MODEL OF HUMAN CHRONIC LYMPHOCYTIC LEUKEMIA. EPIGENETIC ALTERATIONS, INCLUDING GAIN OR LOSS OF DNA METHYLATION, ARE A HALLMARK OF NEARLY EVERY MALIGNANCY. CHANGES IN DNA METHYLATION CAN IMPACT EXPRESSION OF CANCER-RELATED GENES INCLUDING APOPTOSIS REGULATORS AND TUMOR SUPPRESSORS. BECAUSE SUCH EPIGENETIC CHANGES ARE REVERSIBLE, THEY ARE BEING AGGRESSIVELY INVESTIGATED AS POTENTIAL THERAPEUTIC TARGETS. HERE WE USE THE EMU-TCL1 TRANSGENIC MOUSE MODEL OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) TO DETERMINE THE TIMING AND PATTERNS OF ABERRANT DNA METHYLATION, AND TO INVESTIGATE THE MECHANISMS THAT LEAD TO ABERRANT DNA METHYLATION. WE SHOW THAT CLL CELLS FROM EMU-TCL1 MICE AT VARIOUS STAGES RECAPITULATE EPIGENETIC ALTERATIONS SEEN IN HUMAN CLL. ABERRANT METHYLATION OF PROMOTER SEQUENCES IS OBSERVED AS EARLY AS 3 MONTHS OF AGE IN THESE ANIMALS, WELL BEFORE DISEASE ONSET. ABNORMALLY METHYLATED PROMOTER REGIONS INCLUDE BINDING SITES FOR THE TRANSCRIPTION FACTOR FOXD3. WE SHOW THAT LOSS OF FOXD3 EXPRESSION DUE TO AN NF-KAPPAB P50/P50:HDAC1 REPRESSOR COMPLEX OCCURS IN TCL1-POSITIVE B CELLS BEFORE METHYLATION. THEREFORE, SPECIFIC TRANSCRIPTIONAL REPRESSION IS AN EARLY EVENT LEADING TO EPIGENETIC SILENCING OF TARGET GENES IN MURINE AND HUMAN CLL. THESE RESULTS PROVIDE STRONG RATIONALE FOR THE DEVELOPMENT OF STRATEGIES TO TARGET NF-KAPPAB COMPONENTS IN CLL AND POTENTIALLY OTHER B-CELL MALIGNANCIES. 2009 20 164 39 ABNORMAL HISTONE METHYLATION IS RESPONSIBLE FOR INCREASED VASCULAR ENDOTHELIAL GROWTH FACTOR 165A SECRETION FROM AIRWAY SMOOTH MUSCLE CELLS IN ASTHMA. VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF), A KEY ANGIOGENIC MOLECULE, IS ABERRANTLY EXPRESSED IN SEVERAL DISEASES INCLUDING ASTHMA WHERE IT CONTRIBUTES TO BRONCHIAL VASCULAR REMODELING AND CHRONIC INFLAMMATION. ASTHMATIC HUMAN AIRWAY SMOOTH MUSCLE CELLS HYPERSECRETE VEGF, BUT THE MECHANISM IS UNCLEAR. IN THIS STUDY, WE DEFINED THE MECHANISM IN HUMAN AIRWAY SMOOTH MUSCLE CELLS FROM NONASTHMATIC AND ASTHMATIC PATIENTS. WE FOUND THAT ASTHMATIC CELLS LACKED A REPRESSION COMPLEX AT THE VEGF PROMOTER, WHICH WAS PRESENT IN NONASTHMATIC CELLS. RECRUITMENT OF G9A, TRIMETHYLATION OF HISTONE H3 AT LYSINE 9 (H3K9ME3), AND A RESULTANT DECREASE IN RNA POLYMERASE II AT THE VEGF PROMOTER WAS CRITICAL TO REPRESSION OF VEGF SECRETION IN NONASTHMATIC CELLS. AT THE ASTHMATIC PROMOTER, H3K9ME3 WAS ABSENT BECAUSE OF FAILED RECRUITMENT OF G9A; RNA POLYMERASE II BINDING, IN ASSOCIATION WITH TATA-BINDING PROTEIN-ASSOCIATED FACTOR 1, WAS INCREASED; H3K4ME3 WAS PRESENT; AND SP1 BINDING WAS EXAGGERATED AND SUSTAINED. IN CONTRAST, DNA METHYLATION AND HISTONE ACETYLATION WERE SIMILAR IN ASTHMATIC AND NONASTHMATIC CELLS. THIS IS THE FIRST STUDY, TO OUR KNOWLEDGE, TO SHOW THAT AIRWAY CELLS IN ASTHMA HAVE ALTERED EPIGENETIC REGULATION OF REMODELING GENE(S). HISTONE METHYLATION AT GENES SUCH AS VEGF MAY BE AN IMPORTANT NEW THERAPEUTIC TARGET. 2012