1 1632 124 DNMTS ARE INVOLVED IN TGF-BETA1-INDUCED EPITHELIAL-MESENCHYMAL TRANSITIONS IN AIRWAY EPITHELIAL CELLS. CHRONIC RHINOSINUSITIS (CRS) PATHOGENESIS IS CLOSELY RELATED TO TISSUE REMODELING, INCLUDING EPITHELIAL-MESENCHYMAL TRANSITION (EMT). EPIGENETIC MECHANISMS PLAY KEY ROLES IN EMT. DNA METHYLATION, MEDIATED BY DNA METHYLTRANSFERASES (DNMTS), IS AN EPIGENETIC MARKER THAT IS CRITICAL TO EMT. THE GOAL OF THIS STUDY WAS TO DETERMINE WHETHER DNMTS WERE INVOLVED IN TGF-BETA1-INDUCED EMT AND ELUCIDATE THE UNDERLYING MECHANISMS IN NASAL EPITHELIAL CELLS AND AIR-LIQUID INTERFACE CULTURES. GLOBAL DNA METHYLATION AND DNMT ACTIVITY WERE QUANTIFIED. DNMT EXPRESSION WAS MEASURED USING REAL-TIME PCR (QRT-PCR) IN HUMAN CRS TISSUES. MRNA AND PROTEIN LEVELS OF DNMTS, E-CADHERIN, VIMENTIN, ALPHA-SMA, AND FIBRONECTIN WERE DETERMINED USING RT-PCR AND WESTERN BLOTTING, RESPECTIVELY. DNMT1, DNMT3A, AND DNMT3B GENE EXPRESSION WERE KNOCKED DOWN USING SIRNA TRANSFECTION. MAPK PHOSPHORYLATION AND EMT-RELATED TRANSCRIPTION FACTOR LEVELS WERE DETERMINED USING WESTERN BLOTTING. SIGNALING PATHWAYS WERE ANALYZED USING SPECIFIC INHIBITORS OF MAPK. WE DEMONSTRATED THESE DATA IN PRIMARY NASAL EPITHELIAL CELLS AND AIR-LIQUID INTERFACE CULTURES. GLOBAL DNA METHYLATION, DNMT ACTIVITY, AND DNMT EXPRESSION INCREASED IN CRS TISSUES. DNMT EXPRESSION WAS POSITIVELY CORRELATED WITH LUND-MCKAY CT SCORES. TGF-BETA1 DOSE-DEPENDENTLY INDUCED DNMT EXPRESSION. FURTHER, 5-AZA INHIBITED TGF-BETA1-INDUCED DNMT, SNAIL, AND SLUG EXPRESSION RELATED TO EMT, AS WELL AS P38 AND JNK PHOSPHORYLATION IN A549 CELLS AND TGF-BETA1-INDUCED DNMT EXPRESSION AND EMT IN PRIMARY NASAL EPITHELIAL CELLS AND AIR-LIQUID INTERFACE CULTURES. TGF-BETA1-INDUCED DNMT EXPRESSION LEADS TO DNA METHYLATION AND EMT VIA P38, JNK, SNAIL, AND SLUG SIGNALING PATHWAYS. INHIBITION OF DNMT SUPPRESSED THE EMT PROCESS AND THEREFORE IS POTENTIALLY A CRS THERAPEUTIC STRATEGY. 2022 2 922 33 CHRONIC IL-1BETA-INDUCED INFLAMMATION REGULATES EPITHELIAL-TO-MESENCHYMAL TRANSITION MEMORY PHENOTYPES VIA EPIGENETIC MODIFICATIONS IN NON-SMALL CELL LUNG CANCER. CHRONIC INFLAMMATION FACILITATES TUMOR PROGRESSION. WE DISCOVERED THAT A SUBSET OF NON-SMALL CELL LUNG CANCER CELLS UNDERWENT A GRADUALLY PROGRESSING EPITHELIAL-TO-MESENCHYMAL (EMT) PHENOTYPE FOLLOWING A 21-DAY EXPOSURE TO IL-1BETA, AN ABUNDANT PROINFLAMMATORY CYTOKINE IN THE AT-RISK FOR LUNG CANCER PULMONARY AND THE LUNG TUMOR MICROENVIRONMENTS. PATHWAY ANALYSIS OF THE GENE EXPRESSION PROFILE AND IN VITRO FUNCTIONAL STUDIES REVEALED THAT THE EMT AND EMT-ASSOCIATED PHENOTYPES, INCLUDING ENHANCED CELL INVASION, PD-L1 UPREGULATION, AND CHEMORESISTANCE, WERE SUSTAINED IN THE ABSENCE OF CONTINUOUS IL-1BETA EXPOSURE. WE REFERRED TO THIS PHENOMENON AS EMT MEMORY. UTILIZING A DOXYCYCLINE-CONTROLLED SLUG EXPRESSION SYSTEM, WE FOUND THAT HIGH EXPRESSION OF THE TRANSCRIPTION FACTOR SLUG WAS INDISPENSABLE FOR THE ESTABLISHMENT OF EMT MEMORY. HIGH SLUG EXPRESSION IN TUMORS OF LUNG CANCER PATIENTS WAS ASSOCIATED WITH POOR SURVIVAL. CHEMICAL OR GENETIC INHIBITION OF SLUG UPREGULATION PREVENTED EMT FOLLOWING THE ACUTE IL-1BETA EXPOSURE BUT DID NOT REVERSE EMT MEMORY. CHROMATIN IMMUNOPRECIPITATION AND METHYLATION-SPECIFIC PCR FURTHER REVEALED A SLUG-MEDIATED TEMPORAL REGULATION OF EPIGENETIC MODIFICATIONS, INCLUDING ACCUMULATION OF H3K27, H3K9, AND DNA METHYLATION, IN THE CDH1 (E-CADHERIN) PROMOTER FOLLOWING THE CHRONIC IL-1BETA EXPOSURE. CHEMICAL INHIBITION OF DNA METHYLATION NOT ONLY RESTORED E-CADHERIN EXPRESSION IN EMT MEMORY, BUT ALSO PRIMED CELLS FOR CHEMOTHERAPY-INDUCED APOPTOSIS. 2020 3 1620 32 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 4 141 34 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 5 1826 43 EFFECTS OF HISTONE DEACETYLASE INHIBITOR ON EXTRACELLULAR MATRIX PRODUCTION IN HUMAN NASAL POLYP ORGAN CULTURES. BACKGROUND: NASAL POLYPOSIS IS ASSOCIATED WITH A CHRONIC INFLAMMATORY CONDITION OF THE SINONASAL MUCOSA AND INVOLVES MYOFIBROBLAST DIFFERENTIATION AND EXTRACELLULAR MATRIX (ECM) ACCUMULATION. EPIGENETIC MODULATION BY HISTONE DEACETYLASE (HDAC) INHIBITORS INCLUDING TRICHOSTATIN A (TSA) HAS BEEN REPORTED TO HAVE INHIBITORY EFFECTS ON MYOFIBROBLAST DIFFERENTIATION IN LUNG AND RENAL FIBROBLASTS. THE PURPOSE OF THIS STUDY WAS TO INVESTIGATE THE INHIBITORY EFFECT OF TSA ON MYOFIBROBLAST DIFFERENTIATION AND ECM PRODUCTION IN NASAL POLYP ORGAN CULTURES. METHODS: NASAL POLYP TISSUES FROM 18 PATIENTS WERE ACQUIRED DURING ENDOSCOPIC SINUS SURGERY. AFTER ORGAN CULTURE, NASAL POLYPS WERE STIMULATED WITH TGF-BETA1 AND THEN TREATED WITH TSA. ALPHA-SMOOTH MUSCLE ACTIN (ALPHA-SMA), FIBRONECTIN, AND COLLAGEN TYPE I EXPRESSION LEVELS WERE EXAMINED BY REVERSE TRANSCRIPTION-POLYMERASE CHAIN REACTION (PCR), REAL-TIME PCR, WESTERN BLOT, AND IMMUNOFLUORESCENT STAINING. HDAC2, HDAC4, AND ACETYLATED H4 EXPRESSION LEVELS WERE ASSAYED BY WESTERN BLOT. CYTOTOXICITY WAS ANALYZED BY THE TERMINAL DEOXYNUCLEOTIDYL TRANSFERASE BIOTIN-DUTP NICK END LABELING ASSAY. RESULTS: THE EXPRESSION LEVELS OF ALPHA-SMA, FIBRONECTIN, AND COLLAGEN TYPE 1 WERE INCREASED IN NASAL POLYP AFTER TRANSFORMING GROWTH FACTOR (TGF) BETA1 TREATMENT. TSA-INHIBITED TGF-BETA1 INDUCED THESE GENE AND PROTEIN EXPRESSION LEVELS. FURTHERMORE, TSA SUPPRESSED PROTEIN EXPRESSION LEVELS OF HDAC2 AND HDAC4. HOWEVER, TSA INDUCED HYPERACETYLATION OF HISTONES H4. TREATMENT WITH TGF-BETA1 WITH OR WITHOUT TSA DID NOT HAVE CYTOTOXIC EFFECT. CONCLUSION: THESE FINDINGS PROVIDE NOVEL INSIGHTS INTO THE EPIGENETIC REGULATION IN MYOFIBROBLAST DIFFERENTIATION AND ECM PRODUCTION OF NASAL POLYP. TSA COULD BE A CANDIDATE OF A THERAPEUTIC AGENT FOR REVERSING THE TGF-BETA1-INDUCED ECM SYNTHESIS THAT LEADS TO NASAL POLYP DEVELOPMENT. 2013 6 3795 36 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 7 3636 33 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 8 4899 31 OXIDATIVE STRESS MEDIATES THE APOPTOSIS AND EPIGENETIC MODIFICATION OF THE BCL-2 PROMOTER VIA DNMT1 IN A CIGARETTE SMOKE-INDUCED EMPHYSEMA MODEL. BACKGROUND: EMPHYSEMA IS A CRUCIAL PATHOLOGICAL CHARACTERISTIC OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). OXIDATIVE STRESS, APOPTOSIS AND EPIGENETIC MECHANISMS CONTRIBUTE TO THE PATHOGENESIS OF EMPHYSEMA. HOWEVER, AN ATTEMPT TO ACCURATELY IDENTIFY WHETHER THESE MECHANISMS INTERACT WITH EACH OTHER AND HOW THEY ARE TRIGGERED HAS NEVER BEEN CONDUCTED. METHOD: THE TOTAL REACTIVE OXYGEN SPECIES (ROS) LEVEL, PULMONARY APOPTOSIS AND B-CELL LYMPHOMA/LEUKEMIA-2 (BCL-2) EXPRESSION, AN APOPTOSIS REGULATOR, WERE DETECTED IN SAMPLES FROM COPD PATIENTS. BISULFITE SEQUENCING PCR (BSP) WAS CONDUCTED TO OBSERVE THE ALTERATIONS IN THE METHYLATION OF THE BCL-2 PROMOTER IN SPECIMENS. THE DYSREGULATION OF DNA METHYLTRANSFERASE ENZYME 1 (DNMT1), A VITAL DNA METHYLTRANSFERASE ENZYME, IN THE LUNGS OF PATIENTS WAS CONFIRMED THROUGH WESTERN BLOTTING. TO FIND OUT INTERACTIONS BETWEEN OXIDATIVE STRESS AND DNA METHYLATION IN EMPHYSEMA, MOUSE MODELS WERE BUILT WITH ANTIOXIDANT TREATMENT AND DNMT1 SILENCING, AND WERE EXAMINED WITH THE PULMONARY APOPTOSIS, BCL-2 AND DNMT1 LEVELS, AND EPIGENETIC ALTERATIONS OF BCL-2. RESULTS: HIGHER ROS LEVELS AND PULMONARY APOPTOSIS WERE OBSERVED IN COPD PATIENTS THAN IN HEALTHY CONTROLS. DOWNREGULATED BCL-2 EXPRESSION WITH INCREASED PROMOTER METHYLATION AND DNMT1 PROTEIN EXPRESSION WAS FOUND IN COPD PATIENTS. ANTIOXIDANT TREATMENT REDUCED THE LEVEL OF ROS, DNMT1 PROTEIN AND EMPHYSEMATOUS PROGRESSION IN THE SMOKING MODELS. FOLLOWING DNMT1 BLOCKADE, SMOKING MODELS SHOWED IMPROVED LUNG FUNCTION, PULMONARY APOPTOSIS, EMPHYSEMATOUS PROGRESSION, AND INCREASED BCL-2 PROTEIN LEVEL WITH LESS PROMOTER METHYLATION THAN EMPHYSEMA MICE. CONCLUSION: CIGARETTE-INDUCED OXIDATIVE STRESS MEDIATES PULMONARY APOPTOSIS AND HYPERMETHYLATION OF THE BCL-2 PROMOTER IN EMPHYSEMA MODELS THROUGH DNMT1. 2020 9 6661 33 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 4900 37 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 11 2748 35 EXPRESSION AND FUNCTION OF EZH2 IN SYNOVIAL FIBROBLASTS: EPIGENETIC REPRESSION OF THE WNT INHIBITOR SFRP1 IN RHEUMATOID ARTHRITIS. OBJECTIVES: TO STUDY THE EXPRESSION, REGULATION AND FUNCTION OF THE HISTONE METHYLTRANSFERASE ENHANCER OF ZESTE HOMOLOGUE 2 (EZH2) IN SYNOVIAL FIBROBLASTS (SF) FROM PATIENTS WITH RHEUMATOID ARTHRITIS (RA) AND OSTEOARTHRITIS (OA). METHODS: SF WERE OBTAINED FROM RA AND OA PATIENTS UNDERGOING JOINT SURGERY. EXPRESSION LEVELS WERE ASSESSED BY QUANTITATIVE REAL-TIME PCR AND WESTERN BLOT. KINASE INHIBITORS AND REPORTER GENE ASSAYS WERE EMPLOYED TO STUDY SIGNALLING PATHWAYS. FUNCTIONAL ANALYSES INCLUDED EZH2 OVEREXPRESSION BY PLASMID TRANSFECTION AND GENE SILENCING BY SMALL INTERFERING RNA. CHROMATIN IMMUNOPRECIPITATION ASSAY WAS USED TO ANALYSE HISTONE METHYLATION WITHIN DISTINCT PROMOTER REGIONS. RESULTS: BY STUDYING THE EXPRESSION AND FUNCTION OF EZH2 IN SF THE AUTHORS FOUND THAT EZH2 IS OVEREXPRESSED IN RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLASTS (RASF) AND FURTHER INDUCED BY TUMOUR NECROSIS FACTOR ALPHA THROUGH THE NUCLEAR FACTOR KAPPA B AND JUN KINASE PATHWAYS. AS A TARGET GENE OF EZH2 THE AUTHORS IDENTIFIED SECRETED FRIZZLED-RELATED PROTEIN 1 (SFRP1), AN INHIBITOR OF WNT SIGNALLING, WHICH IS ASSOCIATED WITH THE ACTIVATION OF RASF, AND SHOW THAT SFRP1 EXPRESSION CORRELATES WITH THE OCCUPATION OF ITS PROMOTER WITH ACTIVATING AND SILENCING HISTONE MARKS. CONCLUSIONS: THESE DATA STRONGLY SUGGEST THAT THE CHRONIC INFLAMMATORY ENVIRONMENT OF THE RA JOINT INDUCES EZH2 AND THUS MIGHT CAUSE CHANGES IN THE EPIGENETIC PROGRAMMES OF SF. 2011 12 2910 36 GENE EXPRESSION PROFILING OF EPIGENETIC CHROMATIN MODIFICATION ENZYMES AND HISTONE MARKS BY CIGARETTE SMOKE: IMPLICATIONS FOR COPD AND LUNG CANCER. CHROMATIN-MODIFYING ENZYMES MEDIATE DNA METHYLATION AND HISTONE MODIFICATIONS ON RECRUITMENT TO SPECIFIC TARGET GENE LOCI IN RESPONSE TO VARIOUS STIMULI. THE KEY ENZYMES THAT REGULATE CHROMATIN ACCESSIBILITY FOR MAINTENANCE OF MODIFICATIONS IN DNA AND HISTONES, AND FOR MODULATION OF GENE EXPRESSION PATTERNS IN RESPONSE TO CIGARETTE SMOKE (CS), ARE NOT KNOWN. WE HYPOTHESIZE THAT CS EXPOSURE ALTERS THE GENE EXPRESSION PATTERNS OF CHROMATIN-MODIFYING ENZYMES, WHICH THEN AFFECTS MULTIPLE DOWNSTREAM PATHWAYS INVOLVED IN THE RESPONSE TO CS. WE HAVE, THEREFORE, ANALYZED CHROMATIN-MODIFYING ENZYME PROFILES AND VALIDATED BY QUANTITATIVE REAL-TIME PCR (QPCR). WE ALSO PERFORMED IMMUNOBLOT ANALYSIS OF TARGETED HISTONE MARKS IN C57BL/6J MICE EXPOSED TO ACUTE AND SUBCHRONIC CS, AND OF LUNGS FROM NONSMOKERS, SMOKERS, AND PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). WE FOUND A SIGNIFICANT INCREASE IN EXPRESSION OF SEVERAL CHROMATIN MODIFICATION ENZYMES, INCLUDING DNA METHYLTRANSFERASES, HISTONE ACETYLTRANSFERASES, HISTONE METHYLTRANSFERASES, AND SET DOMAIN PROTEINS, HISTONE KINASES, AND UBIQUITINASES. OUR QPCR VALIDATION DATA REVEALED A SIGNIFICANT DOWNREGULATION OF DNMT1, DNMT3A, DNMT3B, HDAC2, HDAC4, HAT1, PRMT1, AND AURKB WE IDENTIFIED TARGETED CHROMATIN HISTONE MARKS (H3K56AC AND H4K12AC), WHICH ARE INDUCED BY CS. THUS CS-INDUCED GENOTOXIC STRESS DIFFERENTIALLY AFFECTS THE EXPRESSION OF EPIGENETIC MODULATORS THAT REGULATE TRANSCRIPTION OF TARGET GENES VIA DNA METHYLATION AND SITE-SPECIFIC HISTONE MODIFICATIONS. THIS MAY HAVE IMPLICATIONS IN DEVISING EPIGENETIC-BASED THERAPIES FOR COPD AND LUNG CANCER. 2016 13 5795 32 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 14 476 44 ARSENIC INDUCES FIBROGENIC CHANGES IN HUMAN KIDNEY EPITHELIAL CELLS POTENTIALLY THROUGH EPIGENETIC ALTERATIONS IN DNA METHYLATION. ARSENIC CONTAMINATION IS A SIGNIFICANT PUBLIC HEALTH ISSUE, AND KIDNEY IS ONE OF THE TARGET ORGAN FOR ARSENIC-INDUCED ADVERSE EFFECTS. RENAL FIBROSIS IS A WELL-KNOWN PATHOLOGICAL STAGE FREQUENTLY OBSERVED IN PROGRESSIVE CHRONIC KIDNEY DISEASE (CKD). EPIDEMIOLOGICAL STUDIES IMPLICATE ARSENIC EXPOSURE TO CKD, BUT THE ROLE OF ARSENIC IN KIDNEY FIBROSIS AND THE UNDERLYING MECHANISM IS STILL UNCLEAR. IT IS IN THIS CONTEXT THAT THE CURRENT STUDY EVALUATED THE EFFECTS OF LONG-TERM ARSENIC EXPOSURE ON THE CELLULAR RESPONSE IN MORPHOLOGY, AND MARKER GENES EXPRESSION WITH RESPECT TO FIBROSIS USING HUMAN KIDNEY 2 (HK-2) EPITHELIAL CELLS. RESULTS OF THIS STUDY REVEALED THAT IN ADDITION TO INCREASED GROWTH, HK-2 CELLS UNDERWENT PHENOTYPIC, BIOCHEMICAL AND MOLECULAR CHANGES INDICATIVE OF EPITHELIAL-MESENCHYMAL TRANSITION (EMT) IN RESPONSE TO THE EXPOSURE TO ARSENIC. MOST IMPORTANTLY, THE ARSENIC-EXPOSED CELLS ACQUIRED THE PATHOGENIC FEATURES OF FIBROSIS AS SUPPORTED BY INCREASED EXPRESSION OF MARKERS FOR FIBROSIS, SUCH AS COLLAGEN I, FIBRONECTIN, TRANSFORMING GROWTH FACTOR BETA, AND ALPHA-SMOOTH MUSCLE ACTIN. UPREGULATION OF FIBROSIS ASSOCIATED SIGNALING MOLECULES SUCH AS TISSUE INHIBITOR OF METALLOPROTEINASES-3 AND MATRIX METALLOPROTEINASE-2 AS WELL AS ACTIVATION OF AKT WAS ALSO OBSERVED. ADDITIONALLY, THE EXPRESSION OF EPIGENETIC GENES (DNA METHYLTRANSFERASES 3A AND 3B; METHYL-CPG BINDING DOMAIN 4) WAS INCREASED IN ARSENIC-EXPOSED CELLS. TREATMENT WITH DNA METHYLATION INHIBITOR 5-AZA-2'-DC REVERSED THE EMT PROPERTIES AND RESTORED THE LEVEL OF PHOSPHO-AKT. TOGETHER, THESE DATA FOR THE FIRST TIME SUGGEST THAT LONG-TERM EXPOSURE TO ARSENIC CAN INCREASE THE RISK OF KIDNEY FIBROSIS. ADDITIONALLY, OUR DATA SUGGEST THAT THE ARSENIC-INDUCED FIBROTIC CHANGES ARE, AT LEAST IN PART, MEDIATED BY DNA METHYLATION AND THEREFORE POTENTIALLY CAN BE REVERSED BY EPIGENETIC THERAPEUTICS. 2019 15 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 16 1500 35 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 17 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 18 5417 48 REGULATION OF DNA METHYLATION IN RHEUMATOID ARTHRITIS SYNOVIOCYTES. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC INFLAMMATORY DISEASE IN WHICH FIBROBLAST-LIKE SYNOVIOCYTES (FLS) EXHIBIT AN AGGRESSIVE PHENOTYPE. ALTHOUGH THE MECHANISMS RESPONSIBLE ARE NOT WELL DEFINED, EPIGENETIC DETERMINANTS SUCH AS DNA METHYLATION MIGHT CONTRIBUTE. DNA METHYLTRANSFERASES (DNMTS) ARE CRITICAL ENZYMES THAT ESTABLISH AND MAINTAIN DNA METHYLATION. WE EVALUATED WHETHER PROINFLAMMATORY CYTOKINES MIGHT CONTRIBUTE TO DIFFERENTIAL DNA METHYLATION PREVIOUSLY DESCRIBED IN RA FLS THROUGH ALTERED DNMT EXPRESSION. FLS WERE OBTAINED FROM RA AND OSTEOARTHRITIS (OA) SYNOVIUM AT THE TIME OF TOTAL JOINT REPLACEMENT. GENE EXPRESSION WAS DETERMINED BY QUANTITATIVE REAL-TIME PCR AND PROTEIN EXPRESSION BY WESTERN BLOT ANALYSIS. DNMT ACTIVITY WAS MEASURED WITH A FUNCTIONAL ASSAY, AND GLOBAL METHYLATION WAS DETERMINED BY AN IMMUNOASSAY THAT DETECTS METHYLCYTOSINE. RESTING EXPRESSION OF DNMT1, -3A, AND -3B MRNA WERE SIMILAR IN RA AND OA FLS. WESTERN BLOT SHOWED ABUNDANT DNMT1 AND DNMT3A PROTEIN. EXPOSURE TO IL-1 DECREASED DNMT1 AND DNMT3A MRNA EXPRESSION IN FLS. DOSE RESPONSES DEMONSTRATED DECREASED DNMT EXPRESSION AT CONCENTRATIONS AS LOW AS 1 PG/ML OF IL-1. DNMT MRNA LEVELS DECREASED RAPIDLY, WITH SIGNIFICANT SUPPRESSION AFTER 2-8 H OF IL-1 STIMULATION. IL-1 STIMULATION OF OA FLS DID NOT AFFECT METHYLATION OF LINE1 SITES BUT LED TO DEMETHYLATION OF A CHI3L1 LOCUS THAT IS HYPOMETHYLATED IN RA FLS. CHRONIC IL-1 STIMULATION ALSO MIMICKED THE EFFECT OF A DNMT INHIBITOR ON FLS GENE EXPRESSION. EXPOSURE TO PROINFLAMMATORY MEDIATORS REVERSIBLY ALTERS DNA METHYLATION IN FLS BY DECREASING DNMT EXPRESSION AND FUNCTION. THESE DATA SUGGEST THAT IL-1 CAN POTENTIALLY IMPRINT CELLS IN CHRONIC INFLAMMATORY DISEASES. 2013 19 902 34 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 20 2825 35 FLOW-DEPENDENT EPIGENETIC REGULATION OF IGFBP5 EXPRESSION BY H3K27ME3 CONTRIBUTES TO ENDOTHELIAL ANTI-INFLAMMATORY EFFECTS. RATIONALE: ATHEROSCLEROSIS IS A CHRONIC INFLAMMATORY AND EPIGENETIC DISEASE THAT IS INFLUENCED BY DIFFERENT PATTERNS OF BLOOD FLOW. HOWEVER, THE EPIGENETIC MECHANISM WHEREBY ATHEROPROTECTIVE FLOW CONTROLS ENDOTHELIAL GENE PROGRAMMING REMAINS ELUSIVE. HERE, WE INVESTIGATED THE POSSIBILITY THAT FLOW ALTERS ENDOTHELIAL GENE EXPRESSION THROUGH EPIGENETIC MECHANISMS. METHODS: EN FACE STAINING AND WESTERN BLOT WERE USED TO DETECT PROTEIN EXPRESSION. REAL-TIME PCR WAS USED TO DETERMINE RELATIVE GENE EXPRESSION. RNA-SEQUENCING OF HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS TREATED WITH SIRNA OF ENHANCER OF ZESTE HOMOLOG 2 (EZH2) OR LAMINAR FLOW WAS USED FOR TRANSCRIPTIONAL PROFILING. RESULTS: WE FOUND THAT TRIMETHYLATION OF HISTONE 3 LYSINE 27 (H3K27ME3), A REPRESSIVE EPIGENETIC MARK THAT ORCHESTRATES GENE REPRESSION, WAS REDUCED IN LAMINAR FLOW AREAS OF MOUSE AORTA AND FLOW-TREATED HUMAN ENDOTHELIAL CELLS. THE DECREASE OF H3K27ME3 PARALLELED A REDUCTION IN THE EPIGENETIC "WRITER"-EZH2, THE CATALYTIC SUBUNIT OF THE POLYCOMB REPRESSIVE COMPLEX 2 (PRC2). MOREOVER, LAMINAR FLOW DECREASED EXPRESSION OF EZH2 VIA MECHANOSENSITIVE MIR101. GENOME-WIDE TRANSCRIPTOME PROFILING STUDIES IN ENDOTHELIAL CELLS TREATED WITH EZH2 SIRNA AND FLOW REVEALED THE UPREGULATION OF NOVEL MECHANOSENSITIVE GENE IGFBP5 (INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN 5), WHICH IS EPIGENETICALLY SILENCED BY H3K27ME3. FUNCTIONALLY, INHIBITION OF H3K27ME3 BY EZH2 SIRNA OR GSK126 (A SPECIFIC EZH2 INHIBITOR) REDUCED H3K27ME3 LEVELS AND MONOCYTE ADHESION TO ENDOTHELIAL CELLS. ADENOVIRAL OVEREXPRESSION OF IGFBP5 ALSO RECAPITULATED THE ANTI-INFLAMMATORY EFFECTS OF H3K27ME3 INHIBITION. MORE IMPORTANTLY, WE OBSERVED EZH2 UPREGULATION, AND IGFBP5 DOWNREGULATION, IN ADVANCED ATHEROSCLEROTIC PLAQUES FROM HUMAN PATIENTS. CONCLUSION: TAKEN TOGETHER, OUR FINDINGS REVEAL THAT ATHEROPROTECTIVE FLOW REDUCES H3K27ME3 AS A CHROMATIN-BASED MECHANISM TO AUGMENT THE EXPRESSION OF GENES THAT CONFER AN ANTI-INFLAMMATORY RESPONSE IN THE ENDOTHELIUM. OUR STUDY EXEMPLIFIES FLOW-DEPENDENT EPIGENETIC REGULATION OF ENDOTHELIAL GENE EXPRESSION, AND ALSO SUGGESTS THAT TARGETING THE EZH2/H3K27ME3/IGFBP5 PATHWAY MAY OFFER NOVEL THERAPEUTICS FOR INFLAMMATORY DISORDERS SUCH AS ATHEROSCLEROSIS. 2018