1 5399 121 REDUCED TEN-ELEVEN TRANSLOCATION AND ISOCITRATE DEHYDROGENASE EXPRESSION IN INFLAMMATORY HIDRADENITIS SUPPURATIVA LESIONS. BACKGROUND: AS ENVIRONMENTAL FACTORS APPEAR TO PREDISPOSE PATIENTS TO HIDRADENITIS SUPPURATIVA (HS), STUDYING EPIGENETIC MODIFICATIONS IS OF INTEREST TO FURTHER UNDERSTAND THE PATHOGENESIS OF HS. OBJECTIVES: TO STUDY THE EXPRESSION OF DNA HYDROXYMETHYLATION REGULATORS, NAMELY THE TEN-ELEVEN TRANSLOCATION (TET) AND ISOCITRATE DEHYDROGENASE (IDH) FAMILY, IN THE SKIN OF HS PATIENTS. MATERIALS & METHODS: TWENTY PATIENTS WITH HS AND 12 HEALTHY SUBJECTS WERE RECRUITED. WE ANALYSED THE EXPRESSION OF TET1, TET2, TET3, IDH1, IDH2, IDH3A, AND IDH3B IN LESIONAL AND PERILESIONAL HS TISSUE AS WELL AS TISSUE FROM HEALTHY CONTROLS BY QUANTITATIVE REAL-TIME REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION (RT-PCR). IN ADDITION, IMMUNOHISTOCHEMISTRY WAS PERFORMED FOR TET1, TET2, AND TET3. RESULTS: RT-PCR ANALYSIS SHOWED THAT MRNA OF ALL THE STUDIED GENES WAS SIGNIFICANTLY UNDER-EXPRESSED IN LESIONAL HS SKIN COMPARED TO HEALTHY SKIN. IDH1 AND IDH2 MRNA EXPRESSION WAS ALSO SIGNIFICANTLY LOWER IN PERILESIONAL HS SKIN COMPARED TO HEALTHY SKIN, AND TET3 MRNA EXPRESSION WAS SIGNIFICANTLY LOWER IN LESIONAL HS SKIN COMPARED TO PERILESIONAL HS SKIN. RT-PCR ANALYSIS FOR TET1, TET2, AND TET3 MRNA EXPRESSION WAS CONFIRMED BY IMMUNOHISTOCHEMICAL ANALYSIS. CORRELATION ANALYSIS REVEALED A SIGNIFICANT POSITIVE CORRELATION BETWEEN TET AND IDH GENE EXPRESSION IN PERILESIONAL AND LESIONAL HS SKIN. CONCLUSIONS: OUR RESULTS SUGGEST THAT EPIGENETIC CHANGES OCCUR IN HS TISSUE AND THAT ABERRANT EXPRESSION OF THE DNA HYDROXYMETHYLATION REGULATORS MAY PLAY A ROLE IN THE PATHOGENESIS OF HS. AS EPIGENETIC MODIFICATIONS ARE REVERSIBLE, FURTHER RESEARCH INTO THE CAUSE OF THESE ABERRANT EXPRESSION PATTERNS IS WARRANTED IN ORDER TO DEVELOP POSSIBLE NOVEL THERAPEUTIC APPROACHES. 2018 2 2762 41 EXPRESSION OF TET2 ENZYME INDICATES ENHANCED EPIGENETIC MODIFICATION OF CELLS IN PERIODONTITIS. DNA METHYLATION IS AN IMPORTANT EPIGENETIC MECHANISM INVOLVED IN THE REGULATION OF GENE EXPRESSION, AND A REDUCTION IN DNA METHYLATION INFLUENCES CELL-CYCLE PROGRESSION AND CELL DIFFERENTIATION IN INFLAMMATORY CELLS. THE AIM OF THE PRESENT STUDY WAS TO ANALYZE THE DNA-METHYLATION PATTERN AT LOCAL AND GLOBAL/SYSTEMIC LEVELS IN PATIENTS WITH PERIODONTITIS AND GINGIVITIS. TWENTY-ONE SUBJECTS WITH GENERALIZED, SEVERE PERIODONTITIS AND 17 SUBJECTS WITH GINGIVAL INFLAMMATION BUT NO ATTACHMENT LOSS WERE RECRUITED. GINGIVAL BIOPSIES AND PERIPHERAL BLOOD SAMPLES WERE COLLECTED AND PREPARED FOR IMMUNOHISTOCHEMICAL ANALYSIS OF 5-METHYLCYTOSINE (5MC), 5-HYDROXYMETHYLCYTOSINE (5HMC), TEN-ELEVEN TRANSLOCATION 2 (TET2), AND DNA METHYLTRANSFERASE 1 (DNMT1). WHILST A SIMILAR PATTERN FOR 5MC AND 5HMC DNA METHYLATION WAS FOUND IN BOTH TYPES OF LESIONS, A SIGNIFICANTLY LARGER PROPORTION OF TET2-POSITIVE CELLS WAS FOUND IN PERIODONTITIS LESIONS THAN IN GINGIVITIS LESIONS. QUANTITATIVE REAL-TIME PCR ANALYSIS SHOWED NO DIFFERENCES BETWEEN GINGIVITIS AND PERIODONTITIS LESIONS REGARDING EXPRESSION OF TET2 AND ISOCITRATE DEHYDROGENASE (IDH) GENES, WHILE THE GLOBAL LEVEL OF 5HMC WAS SIGNIFICANTLY HIGHER IN BLOOD THAN IN TISSUE IN PATIENTS WITH PERIODONTITIS. IT IS SUGGESTED THAT EPIGENETIC CHANGES ARE MORE COMMON IN PERIODONTITIS LESIONS THAN IN GINGIVITIS LESIONS AND THAT SUCH CHANGES ARE TISSUE SPECIFIC. 2016 3 831 43 CHARACTERIZATION OF TET AND IDH GENE EXPRESSION IN CHRONIC LYMPHOCYTIC LEUKEMIA: COMPARISON WITH NORMAL B CELLS AND PROGNOSTIC SIGNIFICANCE. BACKGROUND: CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS THE MOST COMMON HEMATOLOGICAL MALIGNANCY IN WESTERN COUNTRIES, CHARACTERIZED BY A HETEROGENEOUS CLINICAL COURSE. ALTHOUGH GENETIC STUDIES HAVE IDENTIFIED CHROMOSOMAL ABERRATIONS OR SPECIFIC MUTATIONS, EPIGENETIC CHANGES HAVE BEEN POORLY CHARACTERIZED IN CLL. METHODS: WE ASSESSED TEN-ELEVEN TRANSLOCATIONS (TET) 1, 2, AND 3, ISOCITRATE DEHYDROGENASE (IDH) 1, AND 2 MESSENGER RNA (MRNA) EXPRESSION USING REAL-TIME PCR ON PURIFIED LEUKEMIC B CELLS FROM 214 CLL PATIENTS (MEDIAN FOLLOW-UP = 75 MONTHS, RANGE 1-380), NORMAL PERIPHERAL BLOOD B CELLS (N = 20), AND UMBILICAL CORD BLOOD B CELLS (N = 21). THE MICROENVIRONMENT INFLUENCE WAS ASSESSED AFTER 24 H CO-CULTURE OF CLL CELLS WITH BONE MARROW MESENCHYMAL STROMAL CELLS (BMSC). FINALLY, 5-HYDROXYMETHYLCYTOSINE LEVEL (%5-HMC) WAS ASSESSED BY ELISA IN CLL CELLS ALONE OR WITH MICROENVIRONMENT STIMULI. RESULTS: TET 1 AND 3 AND IDH2 WERE DECREASED IN CLL CELLS COMPARED WITH HEALTHY B CELLS (P = 0.0221, 0.0013, <0.0001, RESPECTIVELY), WHILE IDH1 WAS OVEREXPRESSED (P = 0.0037). TET2 AND IDH1 WERE SIGNIFICANTLY CORRELATED WITH TREATMENT-FREE SURVIVAL (TFS); PATIENTS WITH HIGH TET2/IDH1 EXPRESSION HAD A HIGHER MEDIAN TFS (111 MONTHS) THAN PATIENTS WITH LOW EXPRESSION (78 MONTHS, P = 0.0071/0.0123). MOREOVER, TET1 EXPRESSION DECREASED (P = 0.0371), WHILE TET3 AND IDH2 EXPRESSION INCREASED (P = 0.0273/0.0039) IN CO-CULTURES. HOWEVER, %5-HMC WAS NOT CORRELATED WITH CLINICAL DATA AND WAS UNCHANGED FOLLOWING MICROENVIRONMENT STIMULI. CONCLUSIONS: DESPITE A SLIGHT DEREGULATION IN CLL CELLS COMPARED WITH NORMAL B CELLS, WE IDENTIFIED A SIGNIFICANT ASSOCIATION BETWEEN TET/IDH GENE EXPRESSION AND PROGNOSIS, SUGGESTING THAT EPIGENETIC CHANGES COULD POTENTIALLY BE ASSOCIATED WITH DISEASE PROGRESSION. MOREOVER, DESPITE AN IDENTICAL %5-HMC, TET GENE EXPRESSION WAS INFLUENCED BY CONTACT WITH BMSC CONFIRMING THE CRUCIAL ROLE OF THE MICROENVIRONMENT IN CLL PATHOGENESIS. 2016 4 3284 41 HIDRADENITIS SUPPURATIVA PRESENTS A METHYLOME DYSREGULATION CAPABLE TO EXPLAIN THE PRO-INFLAMMATORY MICROENVIRONMENT: ARE THESE DNA METHYLATIONS POTENTIAL THERAPEUTIC TARGETS? BACKGROUND: HIDRADENITIS SUPPURATIVA (HS) IS A CHRONIC, SYSTEMIC, INFLAMMATORY SKIN CONDITION WITH ELUSIVE PATHOGENESIS THAT AFFECTS THERAPEUTIC INTERVENTION DIRECTLY. OBJECTIVE: TO CHARACTERIZE EPIGENETIC VARIATIONS IN CYTOKINES GENES CONTRIBUTING TO HS. METHODS: EPIGENOME-WIDE DNA METHYLATION PROFILING WITH THE ILLUMINA EPIC ARRAY WAS PERFORMED ON BLOOD DNA SAMPLES FROM 24 HS PATIENTS AND 24 AGE- AND SEX-MATCHED CONTROLS TO EXPLORE DNA METHYLATION CHANGES IN CYTOKINE GENES. RESULTS: WE IDENTIFIED 170 CYTOKINE GENES INCLUDING 27 HYPERMETHYLATED CPG SITES AND 143 GENES WITH HYPOMETHYLATED SITES RESPECTIVELY. HYPERMETHYLATED GENES, INCLUDING LIF, HLA-DRB1, HLA-G, MTOR, FADD, TGFB3, MALAT1 AND CCL28; HYPOMETHYLATED GENES, INCLUDING NCSTN, SMAD3, IGF1R, IL1F9, NOD2, NOD1, YY1, DLL1 AND BCL2 MAY CONTRIBUTE TO THE PATHOGENESIS OF HS. THESE GENES WERE ENRICHED IN THE 117 DIFFERENT PATHWAYS (FDR P-VALUES /= C (RS41264459), LOCATED ON THE PROMOTER REGION OF THE AIM2 GENE, WITH A MINOR ALLELE FREQUENCY OF 0.25, WHICH IS MUCH HIGHER THAN THAT REPORTED IN 1000 G AND GNOMAD (0.075 AND 0.094, RESPECTIVELY). THE SAME VARIANT WAS FOUND AT A LOWER ALLELIC FREQUENCY IN SPORADIC HS AND ISOLATED PYODERMA GANGRENOSUM (PG) (0.125 AND 0.065, RESPECTIVELY). CONCLUSION: OUR DATA SUGGEST THAT THIS VARIANT MIGHT PLAY A ROLE IN SUSCEPTIBILITY TO DEVELOP SYNDROMIC FORMS OF HS BUT NOT TO PROGRESS TO SPORADIC HS AND PG. FURTHERMORE, EPIGENETIC AND/OR SOMATIC VARIATIONS COULD AFFECT AIM2 EXPRESSION LEADING TO DIFFERENT, CONTEXT-DEPENDENT RESPONSES. 2023 14 6589 34 TUMOR NECROSIS FACTOR-ALPHA GENE PROMOTER METHYLATION IN JAPANESE ADULTS WITH CHRONIC PERIODONTITIS AND RHEUMATOID ARTHRITIS. BACKGROUND AND OBJECTIVE: OVER-EXPRESSION OF TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA) PLAYS A PATHOLOGICAL ROLE IN CHRONIC PERIODONTITIS (CP) AND RHEUMATOID ARTHRITIS (RA), WHICH MIGHT BE REGULATED BY THE EPIGENETIC MECHANISM. THE AIM OF THE PRESENT STUDY WAS TO EVALUATE WHETHER THERE IS A UNIQUE METHYLATION PROFILE OF THE TNF-ALPHA GENE PROMOTER IN BLOOD CELLS OF INDIVIDUALS WITH CP AND RA. MATERIAL AND METHODS: THE STUDY PARTICIPANTS CONSISTED OF 30 JAPANESE ADULTS WITH RA (RA GROUP), 30 RACE-MATCHED ADULTS WITH CP ONLY (CP GROUP) AND 30 RACE-MATCHED HEALTHY CONTROLS (H GROUP). GENOMIC DNA ISOLATED FROM PERIPHERAL BLOOD WAS MODIFIED BY SODIUM BISULFITE AND ANALYZED, BY DIRECT SEQUENCING, TO INVESTIGATE DNA METHYLATION OF THE TNF-ALPHA GENE PROMOTER REGION. THE LEVEL OF TNF-ALPHA PRODUCED IN MONONUCLEAR CELLS STIMULATED WITH PORPHYROMONAS GINGIVALIS LIPOPOLYSACCHARIDE WAS DETERMINED USING ELISA. RESULTS: TWELVE CYTOSINE-GUANINE DINUCLEOTIDE (CPG) MOTIFS WERE IDENTIFIED IN THE TNF-ALPHA PROMOTER FRAGMENT FROM -343 TO +57 BP. THE CP GROUP SHOWED A SIGNIFICANTLY HIGHER METHYLATION RATE AND FREQUENCY AT -72 BP THAN THE H GROUP (P < 0.01). THE RA GROUP EXHIBITED SIGNIFICANTLY HIGHER METHYLATION RATES AT SEVEN CPG MOTIFS (-302, -163, -119, -72, -49, -38 AND +10 BP), AND SIGNIFICANTLY HIGHER METHYLATION FREQUENCIES AT SIX CPG MOTIFS (-163, -119, -72, -49, -38 AND +10 BP), THAN THE H GROUP (P < 0.01 FOR ALL COMPARISONS). THE LEVELS OF TNF-ALPHA PRODUCED WERE SIGNIFICANTLY DIFFERENT BETWEEN INDIVIDUALS WITH AND WITHOUT METHYLATION AT -163 BP (P = 0.03). CONCLUSION: THESE RESULTS SUGGEST THAT THE HYPERMETHYLATED STATUS OF CPG MOTIFS IN THE TNF-ALPHA GENE PROMOTER IN BLOOD CELLS MAY BE UNIQUE TO JAPANESE ADULTS WITH CP AND RA. 2016 15 1236 30 CURCUMIN AMELIORATES NEPHROSCLEROSIS VIA SUPPRESSION OF HISTONE ACETYLATION INDEPENDENT OF HYPERTENSION. BACKGROUND: ALTHOUGH HISTONE ACETYLATION, AN EPIGENETIC MODIFICATION, HAS BEEN REPORTED TO BE RELATED TO THE PROGRESSION OF VARIOUS DISEASES, ITS INVOLVEMENT IN NEPHROSCLEROSIS IS UNCLEAR. METHODS: DAHL SALT-SENSITIVE RATS WERE USED AS A MODEL OF NEPHROSCLEROSIS IN THIS STUDY. THE RATS WERE DIVIDED INTO THREE GROUPS: (I) NORMAL-SALT DIET GROUP, (II) HIGH-SALT DIET GROUP (HS), AND (III) HS ADMINISTERED DAILY WITH CURCUMIN, A HISTONE ACETYLTRANSFERASE INHIBITOR (HS+C). AT 6 WEEKS AFTER THE TREATMENT, THE KIDNEYS WERE DISSECTED. MORPHOLOGIC CHANGES WERE ASSESSED BY MASSON'S TRICHROME STAINING. THE NUMBER OF MACROPHAGES, FIBROBLASTS AND THE CELLS EXPRESSING ACETYLATED HISTONE H3 AT LYS 9 (H3K9) WERE ASSESSED BY IMMUNOHISTOCHEMISTRY. RESULTS: ALTHOUGH BOTH HS AND HS+C RATS REVEALED A MARKED INCREASE IN SYSTOLIC BLOOD PRESSURE, SERUM CREATININE WAS INCREASED ONLY IN HS RATS AT 6 WEEKS. IN THE HS RATS, NEPHROSCLEROSIS WAS INDUCED, ACCOMPANYING A SIGNIFICANT ACCUMULATION OF MACROPHAGES AND FIBROBLASTS. THE INFLAMMATION AND FIBROSIS WAS MARKEDLY SUPPRESSED IN THE HS+C GROUP. THE LEVEL OF HISTONE ACETYLATION AT LYS 9 WAS ENHANCED IN THE HS RATS, WHEREAS CURCUMIN ADMINISTRATION SUPPRESSED THE HISTONE ACETYLATION. MOREOVER, IN THE HS RATS, INTERLEUKIN-6 GENE EXPRESSION WAS ASSOCIATED WITH ACETYLATED H3K9, AS REVEALED BY CHROMATIN IMMUNOPRECIPITATION ASSAY. CONCLUSIONS: OUR RESULTS SUGGESTED THAT CURCUMIN AMELIORATES NEPHROSCLEROSIS VIA SUPPRESSION OF HISTONE ACETYLATION, INDEPENDENTLY OF HYPERTENSION. 2016 16 3440 34 HYPERMETHYLATION AND LOW TRANSCRIPTION OF TLR2 GENE IN CHRONIC PERIODONTITIS. PERIODONTITIS IS AN INFLAMMATORY DISORDER CHARACTERIZED BY INTERACTIONS BETWEEN PERIODONTAL PATHOGENS AND HOST'S IMMUNE RESPONSE. EPIGENETIC MAY CONTRIBUTE TO DISEASE DEVELOPMENT AND OUTCOME BY INFLUENCING THE EXPRESSION OF GENES INVOLVED IN THE IMMUNE RESPONSE. IT HAS BEEN SHOWN THAT TOLL-LIKE RECEPTORS (TLR) PLAY AN IMPORTANT ROLE IN THE RESPONSE TO PERIODONTOPATHIC BACTERIA. THE AIM OF STUDY WAS TO EVALUATE THE METHYLATION STATUS AND THE EXPRESSION OF TLR2 GENE IN GINGIVAL SAMPLES FROM INDIVIDUALS WITH AND WITHOUT PERIODONTITIS. DNA WAS ANALYZED USING THE METHYL PROFILER DNA METHYLATION QPCR ASSAY. DNA METHYLATION AND TRANSCRIPT LEVELS WERE EVALUATED BY REAL-TIME POLYMERASE CHAIN REACTION. THE PERIODONTITIS GROUP SHOWED A HYPERMETHYLATED PROFILE AND A LOW EXPRESSION OF GENE. POSITIVE CORRELATION BETWEEN THE TLR2 METHYLATION FREQUENCY AND PROBING DEPTH WAS OBSERVED. THIS STUDY GIVES THE FIRST EVIDENCE OF METHYLATION FREQUENCY IN INFLAMED PERIODONTAL TISSUES AND OF THE POSSIBLE PARTICIPATION OF METHYLATION IN THE DEVELOPMENT OF PERIODONTITIS. 2013 17 2771 38 EXTENSIVE PROMOTER DNA HYPERMETHYLATION AND HYPOMETHYLATION IS ASSOCIATED WITH ABERRANT MICRORNA EXPRESSION IN CHRONIC LYMPHOCYTIC LEUKEMIA. DYSREGULATED MICRORNA (MIRNA) EXPRESSION CONTRIBUTES TO THE PATHOGENESIS OF HEMATOPOIETIC MALIGNANCIES, INCLUDING CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). HOWEVER, AN UNDERSTANDING OF THE MECHANISMS THAT CAUSE ABERRANT MIRNA TRANSCRIPTIONAL CONTROL IS LACKING. IN THIS STUDY, WE COMPREHENSIVELY INVESTIGATED THE ROLE AND EXTENT OF MIRNA EPIGENETIC REGULATION IN CLL. GENOME-WIDE PROFILING CONDUCTED ON 24 CLL AND 10 HEALTHY B CELL SAMPLES REVEALED GLOBAL DNA METHYLATION PATTERNS UPSTREAM OF MIRNA SEQUENCES THAT DISTINGUISHED MALIGNANT FROM HEALTHY CELLS AND IDENTIFIED PUTATIVE MIRNA PROMOTERS. INTEGRATION OF DNA METHYLATION AND MIRNA PROMOTER DATA LED TO THE IDENTIFICATION OF 128 RECURRENT MIRNA TARGETS FOR ABERRANT PROMOTER DNA METHYLATION. DNA HYPOMETHYLATION ACCOUNTED FOR MORE THAN 60% OF ALL ABERRANT PROMOTER-ASSOCIATED DNA METHYLATION IN CLL, AND PROMOTER DNA HYPOMETHYLATION WAS RESTRICTED TO WELL-DEFINED REGIONS. INDIVIDUAL HYPER- AND HYPOMETHYLATED PROMOTERS ALLOWED DISCRIMINATION OF CLL SAMPLES FROM HEALTHY CONTROLS. PROMOTER DNA METHYLATION PATTERNS WERE CONFIRMED IN AN INDEPENDENT PATIENT COHORT, WITH 11 MIRNAS CONSISTENTLY SHOWING AN INVERSE CORRELATION BETWEEN DNA METHYLATION STATUS AND EXPRESSION LEVEL. TOGETHER, OUR FINDINGS CHARACTERIZE THE ROLE OF EPIGENETIC CHANGES IN THE REGULATION OF MIRNA TRANSCRIPTION AND CREATE A REPOSITORY OF DISEASE-SPECIFIC PROMOTER REGIONS THAT MAY PROVIDE ADDITIONAL INSIGHTS INTO THE PATHOGENESIS OF CLL. 2012 18 3135 28 GLOBAL DNA METHYLATION AND HYDROXYMETHYLATION LEVELS IN PBMCS ARE ALTERED IN RRMS PATIENTS TREATED WITH IFN-BETA AND GA-A PRELIMINARY STUDY. MULTIPLE SCLEROSIS (MS) IS A CHRONIC DISEASE AFFECTING THE CENTRAL NERVOUS SYSTEM (CNS) DUE TO AN AUTOIMMUNE ATTACK ON AXONAL MYELIN SHEATHS. EPIGENETICS IS AN OPEN RESEARCH TOPIC ON MS, WHICH HAS BEEN INVESTIGATED IN SEARCH OF BIOMARKERS AND TREATMENT TARGETS FOR THIS HETEROGENEOUS DISEASE. IN THIS STUDY, WE QUANTIFIED GLOBAL LEVELS OF EPIGENETIC MARKS USING AN ELISA-LIKE APPROACH IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) FROM 52 PATIENTS WITH MS, TREATED WITH INTERFERON BETA (IFN-BETA) AND GLATIRAMER ACETATE (GA) OR UNTREATED, AND 30 HEALTHY CONTROLS. WE PERFORMED MEDIA COMPARISONS AND CORRELATION ANALYSES OF THESE EPIGENETIC MARKERS WITH CLINICAL VARIABLES IN SUBGROUPS OF PATIENTS AND CONTROLS. WE OBSERVED THAT DNA METHYLATION (5-MC) DECREASED IN TREATED PATIENTS COMPARED WITH UNTREATED AND HEALTHY CONTROLS. MOREOVER, 5-MC AND HYDROXYMETHYLATION (5-HMC) CORRELATED WITH CLINICAL VARIABLES. IN CONTRAST, HISTONE H3 AND H4 ACETYLATION DID NOT CORRELATE WITH THE DISEASE VARIABLES CONSIDERED. GLOBALLY QUANTIFIED EPIGENETIC DNA MARKS 5-MC AND 5-HMC CORRELATE WITH DISEASE AND WERE ALTERED WITH TREATMENT. HOWEVER, TO DATE, NO BIOMARKER HAS BEEN IDENTIFIED THAT CAN PREDICT THE POTENTIAL RESPONSE TO THERAPY BEFORE TREATMENT INITIATION. 2023 19 18 32 5-AZACYTIDINE MODULATES CPG METHYLATION LEVELS OF EZH2 AND NOTCH1 IN MYELODYSPLASTIC SYNDROMES. PURPOSE: MOLECULAR MECHANISMS OF RESPONSE TO HYPOMETHYLATING AGENTS IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES (MDS) AND CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) STILL REMAIN LARGELY UNKNOWN. THEREFORE, THE EFFECTS OF 5-AZACYTIDINE (AZA) ON CLONAL ARCHITECTURE AND DNA METHYLATION WERE INVESTIGATED IN THIS STUDY. METHODS: USING NEXT-GENERATION SEQUENCING (NGS), 30 MYELOID LEUKEMIA-ASSOCIATED GENES WERE ANALYZED IN 15 MDS/CMML PATIENTS WITH EXCELLENT RESPONSE TO AZA. EFFECTS ON METHYLATION LEVELS WERE ANALYZED BY QUANTITATIVE METHYLATION ANALYSIS USING PYROSEQUENCING FOR THE GLOBAL METHYLATION MARKER LINE-1 IN PATIENTS AND MYELOID CELL LINES. VARIOUS MYELOID CELL LINES AND A HEALTHY COHORT WERE SCREENED FOR METHYLATION LEVELS IN 23 GENES. SELECTED TARGETS WERE VERIFIED ON THE MDS/CMML COHORT. RESULTS: THE STUDY PRESENTED HERE SHOWED A STABLE VARIANT ALLELE FREQUENCY AND STABLE GLOBAL METHYLATION LEVELS IN RESPONDING PATIENTS. A SIGNIFICANT DEMETHYLATION OF EZH2 AND NOTCH1 WAS REVEALED IN PATIENTS WITH AZA RESPONSE. CONCLUSIONS: A RESPONSE TO AZA IS NOT ASSOCIATED WITH ERADICATION OF MALIGNANT CLONES, BUT RATHER WITH A STABILIZATION OF THE CLONAL ARCHITECTURE. WE SUGGEST CHANGES IN CPG METHYLATION LEVELS OF EZH2 AND NOTCH1 AS POTENTIAL TARGETS OF EPIGENETIC RESPONSE TO AZA TREATMENT WHICH MAY ALSO SERVE AS USEFUL BIOMARKERS AFTER CLINICAL EVALUATION. 2019 20 1968 35 EPIGENETIC ALTERATION OF THE SOCS1 GENE IN CHRONIC MYELOID LEUKAEMIA. THE EXPRESSION OF THE SUPPRESSOR OF CYTOKINE SIGNALLING-1 (SOCS1) PROTEIN IS INDUCED IN RESPONSE TO STIMULATION BY SEVERAL CYTOKINES. THE INDUCED SOCS1 INHIBITS THE SIGNALLING PATHWAY THROUGH THE ASSOCIATION WITH A VARIETY OF TYROSINE KINASE PROTEINS. IN THIS STUDY, THE MUTATION ANALYSES, CPG ISLAND METHYLATION STATUS, AND THE EXPRESSION OF THE SOCS1 GENE IN 112 CHRONIC MYELOID LEUKAEMIA (CML) SAMPLES, FIVE LEUKAEMIA CELL LINES, AND 30 NORMAL CONTROLS WERE ANALYSED. NO GENETIC MUTATIONS OF SOCS1 GENE WERE NOTED IN THE CML SAMPLES. THE SOCS1 GENE WAS HYPERMETHYLATED IN 67% AND 46% OF THE BLASTIC AND CHRONIC PHASE CML SAMPLES RESPECTIVELY (P < 0.0001). HOWEVER, THERE WAS NO METHYLATION OF THE SOCS1 GENE IN NORMAL CONTROLS OR CML IN MOLECULAR REMISSION. THE METHYLATION STATUS OF THE SOCS1 GENE IS CONSISTENT WITH THE RESULTS OF THE REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION AND IMMUNOCYTOCHEMISTRY STAINING. OUR RESULTS DEMONSTRATE THAT THE SOCS1 GENE SILENCING IS CAUSED BY THE METHYLATION OF CPG ISLANDS IN CML AND IS REVERSED TO AN UNMETHYLATED STATUS IN MOLECULAR REMISSION. AS SOCS1 HAS UNIVERSAL ACTIVITY TO NEGATIVELY REGULATE SEVERAL CYTOKINE SIGNALLING PATHWAYS, THE LOSS OF THE NEGATIVE REGULATION OF CYTOKINE SIGNALLING BY THE SOCS1 MAY PLAY A ROLE IN THE PATHOGENESIS OF CML PROGRESSION. 2003