1 6661 108 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 2 3795 49 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 3 3791 48 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 4 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 5 3527 32 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 6 5972 29 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 7 4004 38 LOSS OF THE POLYCOMB MARK FROM BIVALENT PROMOTERS LEADS TO ACTIVATION OF CANCER-PROMOTING GENES IN COLORECTAL TUMORS. IN COLON TUMORS, THE TRANSCRIPTION OF MANY GENES BECOMES DEREGULATED BY POORLY DEFINED EPIGENETIC MECHANISMS THAT HAVE BEEN STUDIED MAINLY IN ESTABLISHED CELL LINES. IN THIS STUDY, WE USED FROZEN HUMAN COLON TISSUES TO ANALYZE PATTERNS OF HISTONE MODIFICATION AND DNA CYTOSINE METHYLATION IN CANCER AND MATCHED NORMAL MUCOSA SPECIMENS. DNA METHYLATION IS STRONGLY TARGETED TO BIVALENT H3K4ME3- AND H3K27ME3-ASSOCIATED PROMOTERS, WHICH LOSE BOTH HISTONE MARKS AND ACQUIRE DNA METHYLATION. HOWEVER, WE FOUND THAT LOSS OF THE POLYCOMB MARK H3K27ME3 FROM BIVALENT PROMOTERS WAS ACCOMPANIED OFTEN BY ACTIVATION OF GENES ASSOCIATED WITH CANCER PROGRESSION, INCLUDING NUMEROUS STEM CELL REGULATORS, ONCOGENES, AND PROLIFERATION-ASSOCIATED GENES. INDEED, WE FOUND MANY OF THESE SAME GENES WERE ALSO ACTIVATED IN PATIENTS WITH ULCERATIVE COLITIS WHERE CHRONIC INFLAMMATION PREDISPOSES THEM TO COLON CANCER. BASED ON OUR FINDINGS, WE PROPOSE THAT A LOSS OF POLYCOMB REPRESSION AT BIVALENT GENES COMBINED WITH AN ENSUING SELECTION FOR TUMOR-DRIVING EVENTS PLAYS A MAJOR ROLE IN CANCER PROGRESSION. 2014 8 141 32 ABERRANT DNA METHYLATION OF MTOR PATHWAY GENES PROMOTES INFLAMMATORY ACTIVATION OF IMMUNE CELLS IN DIABETIC KIDNEY DISEASE. DNA METHYLATION HAS BEEN IMPLICATED IN THE PATHOGENESIS OF DIABETIC KIDNEY DISEASE (DKD), BUT THE UNDERLYING MECHANISMS REMAIN UNCLEAR. IN THIS STUDY, WE TESTED THE HYPOTHESIS THAT ABERRANT DNA METHYLATION IN PERIPHERAL IMMUNE CELLS CONTRIBUTES TO DKD PROGRESSION. WE SHOWED THAT LEVELS OF DNA METHYLTRANSFERASE 1 (DNMT1), A KEY ENZYME FOR DNA METHYLATION, WERE INCREASED ALONG WITH INFLAMMATORY ACTIVITY OF PERIPHERAL BLOOD MONONUCLEAR CELLS IN DKD PATIENTS. INHIBITION OF DNMT1 WITH 5-AZA-2'-DEOXYCYTIDINE (5-AZA) MARKEDLY INCREASED THE PROPORTION OF CD4(+)CD25(+) REGULATORY T CELLS IN PERIPHERAL BLOOD MONONUCLEAR CELLS IN CULTURE AND IN DIABETIC ANIMALS. ADOPTIVE TRANSFER OF IMMUNE CELLS FROM 5-AZA-TREATED ANIMALS SHOWED BENEFICIAL EFFECTS ON THE HOST IMMUNE SYSTEM, RESULTING IN A SIGNIFICANT IMPROVEMENT OF DKD. USING GENOME-WIDE DNA METHYLATION ASSAYS, WE IDENTIFIED THE DIFFERENTIALLY METHYLATED CYTOSINES IN THE PROMOTER REGIONS OF MAMMALIAN TARGET OF RAPAMYCIN (MTOR) REGULATORS IN PERIPHERAL BLOOD MONONUCLEAR CELLS OF DIABETIC PATIENTS. FURTHER, MRNA ARRAYS CONFIRMED THE CONSISTENT INDUCTION OF GENES EXPRESSED IN THE MTOR PATHWAY. IMPORTANTLY, DOWN-REGULATION OF DNMT1 EXPRESSION VIA RNA INTERFERENCE RESULTED IN PROMINENT CYTOSINE DEMETHYLATION OF MTOR NEGATIVE REGULATORS AND SUBSEQUENT DECREASE OF MTOR ACTIVITY. LASTLY, MODULATION OF MTOR RESULTED IN CHANGES IN THE EFFECT OF 5-AZA ON DIABETIC IMMUNE CELLS. THUS, UP-REGULATION OF DNMT1 IN DIABETIC IMMUNE CELLS INDUCES ABERRANT CYTOSINE METHYLATION OF THE UPSTREAM REGULATORS OF MTOR, LEADING TO PATHOGENIC ACTIVATION OF THE MTOR PATHWAY AND CONSEQUENT INFLAMMATION IN DIABETIC KIDNEYS. HENCE, THIS STUDY HIGHLIGHTS THERAPEUTIC POTENTIAL OF TARGETING EPIGENETIC EVENTS IN IMMUNE SYSTEM FOR TREATING DKD. 2019 9 1500 40 DNA METHYLATION ANALYSIS OF CD4+ T CELLS IN PATIENTS WITH PSORIASIS. PSORIASIS IS A CHRONIC INFLAMMATORY SKIN DISEASE THAT IS CHARACTERIZED BY ABERRANT CROSS-TALK BETWEEN KERATINOCYTES AND IMMUNE CELLS SUCH AS CD4+ T CELLS, RESULTING IN KERATINOCYTE HYPERPROLIFERATION IN THE EPIDERMIS. DNA METHYLATION, ONE OF SEVERAL EPIGENETIC MECHANISMS, PLAYS AN IMPORTANT ROLE IN GENE EXPRESSION WITHOUT CHANGING THE DNA SEQUENCE. SEVERAL STUDIES HAVE SUGGESTED THE INVOLVEMENT OF EPIGENETIC REGULATION IN SKIN LESIONS FROM PATIENTS WITH PSORIASIS. IN THIS STUDY, WE INVESTIGATED THE GENOME-WIDE DNA METHYLATION STATUS OF CD4+ T CELLS IN PATIENTS WITH PSORIASIS COMPARED WITH HEALTHY SUBJECTS USING METHYLATED DNA IMMUNOPRECIPITATION SEQUENCING (MEDIP-SEQ). THE RESULTS OF MEDIP-SEQ SHOWED THAT THE GLOBAL METHYLATION VALUES OF CD4+ T CELLS ARE HIGHER IN PATIENTS WITH PSORIASIS THAN IN HEALTHY CONTROLS, PARTICULARLY IN THE PROMOTER REGIONS. AMONG THE MOST HYPERMETHYLATED GENES IN THE PROMOTER REGIONS, WE SELECTED THE GENES WHOSE EXPRESSION IS SIGNIFICANTLY REDUCED IN THE CD4+ T CELLS OF PSORIASIS PATIENTS. STUDIES USING THE METHYLATION INHIBITOR 5-AZACYTIDINE IN VITRO METHYLATION ASSAYS HAVE SHOWN THAT THE DIFFERENTIAL EXPRESSION LEVELS WERE ASSOCIATED WITH THE METHYLATION STATUS OF EACH GENE. BISULFITE SEQUENCING OF THE TRANSCRIPTION START REGION OF PHOSPHATIDIC ACID PHOSPHATASE TYPE 2 DOMAIN CONTAINING 3 (PPAPDC3), ONE OF THE SELECTED GENES, SHOWED HYPERMETHYLATION IN THE CD4+ T CELLS OF PSORIASIS PATIENTS. THESE RESULTS SUGGESTED THAT THE METHYLATION STATUS, WHICH IS IDENTIFIED BY MEDIP-SEQ OF THE GENES, WAS CORRELATED WITH THE MRNA EXPRESSION LEVEL OF THE GENES. COLLECTIVELY, THE DNA METHYLATION STATUS IN CD4+ T CELLS MIGHT BE ASSOCIATED WITH THE PATHOGENESIS OF PSORIASIS. 2014 10 3636 31 INCREASED DNA METHYLTRANSFERASE ACTIVITY AND DNA METHYLATION FOLLOWING EPIDERMAL GROWTH FACTOR STIMULATION IN OVARIAN CANCER CELLS. OVARIAN CANCER PROGRESSION IS CORRELATED WITH ACCUMULATION OF ABERRANT CPG ISLAND METHYLATION. IN OVARIAN CANCER, ASCITES FLUID CONTAINS NUMEROUS EPIDERMAL-GROWTH-FACTOR-RECEPTOR (EGFR) ACTIVATORS, WHICH COULD RESULT IN A TUMOR MICROENVIRONMENT OF CONSTANT EGFR ACTIVATION. SIGNALING PATHWAYS DOWNSTREAM OF EGFR, SUCH AS RAS, REGULATE DNA METHYLATION. WE HYPOTHESIZED THAT CHRONIC EGFR ACTIVATION COULD ALTER DNA METHYLATION. WE FOUND THAT EGFR ACTIVATION INCREASED DNA METHYLTRANSFERASE (DNMT) ACTIVITY ACUTELY, AS WELL AS AFTER LONG-TERM EGF TREATMENT OR EXPRESSION OF A MUTATIONALLY ACTIVATED EGFR. FURTHERMORE, THIS INCREASE IN DNMT ACTIVITY WAS DEPENDENT ON EGFR CATALYTIC ACTIVITY AND RESULTED IN INCREASED GLOBAL DNA METHYLATION. ADDITIONALLY, TREATMENT WITH THE DNMT INHIBITOR/HYPOMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE (AZA) INHIBITED THE EGF INDUCED INCREASE OF BOTH DNMT ACTIVITY AND GLOBAL METHYLATION. THESE DATA SUPPORT A ROLE FOR EGFR IN THE PROCESS OF ACCUMULATED DNA METHYLATION DURING OVARIAN CANCER PROGRESSION AND SUGGEST THAT EPIGENETIC THERAPY MAY BE BENEFICIAL FOR THE TREATMENT OF OVARIAN CANCER. 2012 11 902 38 CHRONIC EXPOSURE TO ARSENIC, ESTROGEN, AND THEIR COMBINATION CAUSES INCREASED GROWTH AND TRANSFORMATION IN HUMAN PROSTATE EPITHELIAL CELLS POTENTIALLY BY HYPERMETHYLATION-MEDIATED SILENCING OF MLH1. BACKGROUND: CHRONIC EXPOSURE TO ARSENIC AND ESTROGEN IS ASSOCIATED WITH RISK OF PROSTATE CANCER, BUT THEIR MECHANISM IS NOT FULLY UNDERSTOOD. ADDITIONALLY, THE CARCINOGENIC EFFECTS OF THEIR CO-EXPOSURE ARE NOT KNOWN. THEREFORE, THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE THE EFFECTS OF CHRONIC EXPOSURE TO ARSENIC, ESTROGEN, AND THEIR COMBINATION, ON CELL GROWTH AND TRANSFORMATION, AND IDENTIFY THE MECHANISM BEHIND THESE EFFECTS. METHODS: RWPE-1 HUMAN PROSTATE EPITHELIAL CELLS WERE CHRONICALLY EXPOSED TO ARSENIC AND ESTROGEN ALONE AND IN COMBINATION. CELL GROWTH WAS MEASURED BY CELL COUNT AND CELL CYCLE, WHEREAS CELL TRANSFORMATION WAS EVALUATED BY COLONY FORMATION ASSAY. GENE EXPRESSION WAS MEASURED BY QUANTITATIVE REAL-TIME PCR AND CONFIRMED AT PROTEIN LEVEL BY WESTERN BLOT ANALYSIS. MLH1 PROMOTER METHYLATION WAS DETERMINED BY PYROSEQUENCING METHOD. RESULTS: EXPOSURE TO ARSENIC, ESTROGEN, AND THEIR COMBINATIONS INCREASES CELL GROWTH AND TRANSFORMATION IN RWPE-1 CELLS. INCREASED EXPRESSION OF CYCLIN D1 AND BCL2, WHEREAS DECREASED EXPRESSION OF MISMATCH REPAIR GENES MSH4, MSH6, AND MLH1 WAS ALSO OBSERVED. HYPERMETHYLATION OF MLH1 PROMOTER FURTHER SUGGESTED THE EPIGENETIC INACTIVATION OF MLH1 EXPRESSION IN ARSENIC AND ESTROGEN TREATED CELLS. ARSENIC AND ESTROGEN COMBINATION CAUSED GREATER CHANGES THAN THEIR INDIVIDUAL TREATMENTS. CONCLUSIONS: FINDINGS OF THIS STUDY FOR THE FIRST TIME SUGGEST THAT ARSENIC AND ESTROGEN EXPOSURES CAUSE INCREASED CELL GROWTH AND SURVIVAL POTENTIALLY THROUGH EPIGENETIC INACTIVATION OF MLH1 RESULTING IN DECREASED MLH1-MEDIATED APOPTOTIC RESPONSE, AND CONSEQUENTLY INCREASED CELLULAR TRANSFORMATION. 2013 12 2747 41 EXPRESSION ANALYSIS OF THE EPIGENETIC METHYLTRANSFERASES AND METHYL-CPG BINDING PROTEIN FAMILIES IN THE NORMAL B-CELL AND B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). THE IMPORTANCE OF EPIGENETIC MODIFICATIONS IN CARCINOGENESIS HAS BEEN A SOURCE OF CONTROVERSY FOR SOME TIME. THERE IS LITTLE DOUBT THAT CHANGES IN GENOMIC HYPERMETHYLATION CONTRIBUTE TO THE SILENCING OF TUMOR SUPPRESSOR GENES. FURTHERMORE, RECENT STUDIES HAVE ALSO IDENTIFIED THE SIGNIFICANCE OF GENOMIC HYPOMETHYLATION ASSOCIATED WITH CHROMOSOMAL INSTABILITY AND TUMORIGENESIS. ONE OF THE MOST PERPLEXING QUESTIONS REGARDING EPIGENETIC MODIFICATIONS AND LEUKEMOGENESIS IS THE RELATIONSHIP WITH DNA METHYLTRANSFERASES (DNMT'S). THE PRIMARY FUNCTION OF THE DNMT ENZYMES IS TO METHYLATE GENOMIC DNA, WHEREAS THE METHYL-CPG BINDING DOMAIN PROTEINS (MBD) INTERPRET THIS METHYLATION SIGNAL AND REGULATE GENE EXPRESSION AND CHROMATIN BEHAVIOR. IN THIS STUDY WE ANALYSE THESE GENE FAMILIES BY QUANTITATIVE REAL-TIME PCR TO INVESTIGATE WHETHER EXPRESSION LEVELS AND THE B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL) PHENOTYPE ARE ASSOCIATED. FURTHERMORE, GIVEN THE EPIGENETIC CROSSTALK BETWEEN GENOME STABILITY AND THE HISTONE CHROMATIN CODE WE HAVE ANALYSED EUKARYOTIC HISTONE METHYLTRANSFERASE (EU-HMTASEI). SURPRISINGLY, WE DID NOT OBSERVE SIGNIFICANT CHANGES IN DNMT1 EXPRESSION IN B-CLL CASES WHEN COMPARED TO NORMAL LYMPHOCYTES, REGARDLESS OF WHETHER WE NORMALISE AGAINST GAPDH OR PCNA AS REFERENCE STANDARDS. INDEED, EXPRESSION OF THE MAINTENANCE AND DE NOVO METHYLASES WERE INDEPENDENTLY REGULATED. OF PARTICULAR NOTE WAS THE SIGNIFICANT DOWN REGULATION OF DNMT3B. FURTHERMORE, WE OBSERVED A POSITIVE CORRELATION BETWEEN HMTASEI EXPRESSION LEVELS AND STAGE OF LEUKEMIA SUGGESTING THAT CHANGES IN THE METHYLATION PATTERNS IN B-CLL MAY REPRESENT DEREGULATION OF THE EPIGENETIC REPERTOIRE THAT ALSO INCLUDE THE METHYLATION DEPENDENT BINDING PROTEINS, MBD2 AND MECP2. WE ENVISAGE CHANGES IN THE EPIGENETIC PROGRAM ARE MULTIFACTORIAL IN NATURE AND POSTULATE THAT THE PREVALENT GENOMIC METHYLASES JUST ONE COMPONENT OF A LARGER EPIGENETIC REPERTOIRE. 2004 13 1656 32 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 14 978 38 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 15 2297 31 EPIGENETIC REGULATION OF ACUTE INFLAMMATORY PAIN. ACUTE PAIN IS ASSOCIATED WITH TISSUE DAMAGE, WHICH RESULTS IN THE RELEASE OF INFLAMMATORY MEDIATORS. RECENT STUDIES POINT TO THE INVOLVEMENT OF EPIGENETIC MECHANISMS (DNA METHYLATION) IN THE DEVELOPMENT OF PAIN. WE HAVE FOUND THAT DURING ACUTE INFLAMMATORY PAIN INDUCED BY THE APPLICATION OF 10% MUSTARD OIL ON THE TONGUES OF RATS, LEVELS OF DNMT3A AND 3B WERE ELEVATED MARKEDLY (36 AND 42 % RESPECTIVELY), WHEREAS THE LEVEL OF DNMT1 WAS NOT CHANGED SIGNIFICANTLY. PREVIOUS INJECTION OF XEFOCAM WITH 0,4 MG/KG DOSE DECREASED LEVELS OF DNMT3A AND 3B (25 AND 24% RESPECTIVELY). THE LEVEL OF DNMT1 WAS NOT CHANGED SIGNIFICANTLY COMPARED TO THE CONTROL GROUP. THE FINDINGS SUPPORT THE IDEA THAT INHIBITORS OF DNA-METHYLTRANSFERASES COULD BE USEFUL FOR PAIN MANAGEMENT. OUR DATA SUGGEST THAT NSAIDS (ALONE OR IN COMBINATION WITH DNMT INHIBITORS) MAY BE PROPOSED AS POSSIBLE EPIGENETIC REGULATORY AGENTS, WHICH MAY PLAY A ROLE IN EPIGENETIC MECHANISMS INDIRECTLY THROUGH ALTERING THE ACTIVITY OF INFLAMMATORY MEDIATORS INVOLVED IN PAIN DEVELOPMENT. 2014 16 925 33 CHRONIC INFLAMMATION INDUCES A NOVEL EPIGENETIC PROGRAM THAT IS CONSERVED IN INTESTINAL ADENOMAS AND IN COLORECTAL CANCER. CHRONIC INFLAMMATION REPRESENTS A MAJOR RISK FACTOR FOR TUMOR FORMATION, BUT THE UNDERLYING MECHANISMS HAVE REMAINED LARGELY UNKNOWN. EPIGENETIC MECHANISMS CAN RECORD THE EFFECTS OF ENVIRONMENTAL CHALLENGES ON THE GENOME LEVEL AND COULD THEREFORE PLAY AN IMPORTANT ROLE IN THE PATHOGENESIS OF INFLAMMATION-ASSOCIATED TUMORS. USING SINGLE-BASE METHYLATION MAPS AND TRANSCRIPTOME ANALYSES OF A COLITIS-INDUCED MOUSE COLON CANCER MODEL, WE IDENTIFIED A NOVEL EPIGENETIC PROGRAM THAT IS CHARACTERIZED BY HYPERMETHYLATION OF DNA METHYLATION VALLEYS THAT ARE CHARACTERIZED BY LOW CPG DENSITY AND ACTIVE CHROMATIN MARKS. THIS PROGRAM IS CONSERVED AND FUNCTIONAL IN MOUSE INTESTINAL ADENOMAS AND RESULTS IN SILENCING OF ACTIVE INTESTINAL GENES THAT ARE INVOLVED IN GASTROINTESTINAL HOMEOSTASIS AND INJURY RESPONSE. FURTHER ANALYSES REVEAL THAT THE PROGRAM REPRESENTS A PROMINENT FEATURE OF HUMAN COLORECTAL CANCER AND CAN BE USED TO CORRECTLY CLASSIFY COLORECTAL CANCER SAMPLES WITH HIGH ACCURACY. TOGETHER, OUR RESULTS SHOW THAT INFLAMMATORY SIGNALS ESTABLISH A NOVEL EPIGENETIC PROGRAM THAT SILENCES A SPECIFIC SET OF GENES THAT CONTRIBUTE TO INFLAMMATION-INDUCED CELLULAR TRANSFORMATION. 2015 17 3796 44 INTERLEUKIN-6 PROMOTES TUMORIGENESIS BY ALTERING DNA METHYLATION IN ORAL CANCER CELLS. 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. WE ESTABLISHED AN IN VITRO MODEL OF INTERLEUKIN (IL)-6 MEDIATING CHRONIC INFLAMMATION IN OSCC CELL LINES. THEREAFTER, WE MEASURED THE ABILITY OF IL-6 TO INDUCE GLOBAL HYPOMETHYLATION OF LONG INTERSPERSED NUCLEAR ELEMENT-1 (LINE-1) SEQUENCES, AS WELL AS CPG METHYLATION CHANGES USING MULTIPLE METHODOLOGIES INCLUDING QUANTITATIVE PYROSEQUENCING, METHYLATION-SPECIFIC MULTIPLEX LIGATION-DEPENDENT PROBE AMPLIFICATION AND SENSITIVE MELTING ANALYSIS AFTER REAL-TIME-METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (PCR). GENE EXPRESSION WAS INVESTIGATED BY QUANTITATIVE REVERSE TRANSCRIPTASE-PCR. IL-6 INDUCED SIGNIFICANT GLOBAL LINE-1 HYPOMETHYLATION (P=0.016) IN OUR IN VITRO MODEL OF INFLAMMATORY STRESS IN OSCC CELL LINES. SIMULTANEOUSLY, IL-6 INDUCED CPG PROMOTER METHYLATION CHANGES IN SEVERAL IMPORTANT PUTATIVE TUMOR SUPPRESSOR GENES INCLUDING CHFR, GATA5 AND PAX6. METHYLATION CHANGES CORRELATED INVERSELY WITH THE CHANGES IN THE EXPRESSION OF CORRESPONDING GENES. OUR RESULTS INDICATE THAT IL-6-INDUCED INFLAMMATION PROMOTES TUMORIGENESIS IN THE ORAL CAVITY BY ALTERING GLOBAL LINE-1 HYPOMETHYLATION. IN ADDITION, CONCURRENT HYPERMETHYLATION OF MULTIPLE TUMOR SUPPRESSOR GENES BY IL-6 SUGGESTS THAT EPIGENETIC GENE SILENCING MAY BE AN IMPORTANT CONSEQUENCE OF CHRONIC INFLAMMATION IN THE ORAL CAVITY. THESE FINDINGS HAVE CLINICAL RELEVANCE, AS BOTH METHYLATION AND INFLAMMATION ARE SUITABLE TARGETS FOR DEVELOPING NOVEL PREVENTIVE AND THERAPEUTIC MEASURES. 2011 18 5795 38 STAT3 INDUCTION OF MIR-146B FORMS A FEEDBACK LOOP TO INHIBIT THE NF-KAPPAB TO IL-6 SIGNALING AXIS AND STAT3-DRIVEN CANCER PHENOTYPES. INTERLEUKIN-6 (IL-6)-MEDIATED ACTIVATION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3 (STAT3) IS A MECHANISM BY WHICH CHRONIC INFLAMMATION CAN CONTRIBUTE TO CANCER AND IS A COMMON ONCOGENIC EVENT. WE DISCOVERED A PATHWAY, THE LOSS OF WHICH IS ASSOCIATED WITH PERSISTENT STAT3 ACTIVATION IN HUMAN CANCER. WE FOUND THAT THE GENE ENCODING THE TUMOR SUPPRESSOR MICRORNA MIR-146B IS A DIRECT STAT3 TARGET GENE, AND ITS EXPRESSION WAS INCREASED IN NORMAL BREAST EPITHELIAL CELLS BUT DECREASED IN TUMOR CELLS. METHYLATION OF THE MIR-146B PROMOTER, WHICH INHIBITED STAT3-MEDIATED INDUCTION OF EXPRESSION, WAS INCREASED IN PRIMARY BREAST CANCERS. MOREOVER, WE FOUND THAT MIR-146B INHIBITED NUCLEAR FACTOR KAPPAB (NF-KAPPAB)-DEPENDENT PRODUCTION OF IL-6, SUBSEQUENT STAT3 ACTIVATION, AND IL-6/STAT3-DRIVEN MIGRATION AND INVASION IN BREAST CANCER CELLS, THEREBY ESTABLISHING A NEGATIVE FEEDBACK LOOP. IN ADDITION, HIGHER EXPRESSION OF MIR-146B WAS POSITIVELY CORRELATED WITH PATIENT SURVIVAL IN BREAST CANCER SUBTYPES WITH INCREASED IL6 EXPRESSION AND STAT3 PHOSPHORYLATION. OUR RESULTS IDENTIFY AN EPIGENETIC MECHANISM OF CROSSTALK BETWEEN STAT3 AND NF-KAPPAB RELEVANT TO CONSTITUTIVE STAT3 ACTIVATION IN MALIGNANCY AND THE ROLE OF INFLAMMATION IN ONCOGENESIS. 2014 19 1620 41 DNA METHYLTRANSFERASE-MEDIATED TRANSCRIPTIONAL SILENCING IN MALIGNANT GLIOMA: A COMBINED WHOLE-GENOME MICROARRAY AND PROMOTER ARRAY ANALYSIS. EPIGENETIC INACTIVATION OF TUMOR SUPPRESSOR GENES IS A COMMON FEATURE IN HUMAN CANCER. PROMOTER HYPERMETHYLATION AND HISTONE DEACETYLATION ARE REVERSIBLE EPIGENETIC MECHANISMS ASSOCIATED WITH TRANSCRIPTIONAL REGULATION. DNA METHYLTRANSFERASES (DNMT1 AND DNMT3B) REGULATE AND MAINTAIN PROMOTER METHYLATION AND ARE OVEREXPRESSED IN HUMAN CANCER. WE PERFORMED WHOLE-GENOME MICROARRAY ANALYSIS TO IDENTIFY GENES WITH ALTERED EXPRESSION AFTER RNAI-INDUCED SUPPRESSION OF DNMT IN A GLIOBLASTOMA MULTIFORME (GBM) CELL LINE. WE THEN IDENTIFIED GENES WITH BOTH DECREASED EXPRESSION AND EVIDENCE OF PROMOTER CPG ISLAND HYPERMETHYLATION IN GBM TISSUE SAMPLES USING A COMBINED WHOLE-GENOME MICROARRAY TRANSCRIPTOME ANALYSIS IN CONJUNCTION WITH A PROMOTER ARRAY ANALYSIS AFTER DNA IMMUNOPRECIPITATION WITH ANTI-5-METHYLCYTIDINE. DNMT1 AND 3B KNOCKDOWN RESULTED IN THE RESTORED EXPRESSION OF 308 GENES THAT ALSO CONTAINED PROMOTER REGION HYPERMETHYLATION. OF THESE, 43 WERE ALSO FOUND TO BE DOWNREGULATED IN GBM TISSUE SAMPLES. THREE DOWNREGULATED GENES WITH HYPERMETHYLATED PROMOTERS AND RESTORED EXPRESSION IN RESPONSE TO ACUTE DNMT SUPPRESSION WERE ASSAYED FOR METHYLATION CHANGES USING BISULFITE SEQUENCE ANALYSIS OF THE PROMOTER REGION AFTER CHRONIC DNMT SUPPRESSION. RESTORATION OF GENE EXPRESSION WAS NOT ASSOCIATED WITH CHANGES IN PROMOTER REGION METHYLATION, BUT RATHER WITH CHANGES IN HISTONE METHYLATION AND CHROMATIN CONFORMATION. TWO OF THE IDENTIFIED GENES EXHIBITED GROWTH SUPPRESSIVE ACTIVITY IN IN VITRO ASSAYS. COMBINING TARGETED GENETIC MANIPULATIONS WITH COMPREHENSIVE GENOMIC AND EXPRESSION ANALYSES PROVIDES A POTENTIALLY POWERFUL NEW APPROACH FOR IDENTIFYING EPIGENETICALLY REGULATED GENES IN GBM. 2009 20 1615 31 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