1 1613 112 DNA METHYLTRANSFERASE 1 MEDIATED ABERRANT METHYLATION AND SILENCING OF SHP-1 GENE IN CHRONIC MYELOGENOUS LEUKEMIA CELLS. INTRODUCTION: EXTENSIVE STUDIES ON SHP-1 PROTEIN AND SHP-1 MRNA REVEALED THAT THE DIMINISHMENT OR ABOLISHMENT OF THE EXPRESSION OF SHP-1 IN LEUKEMIAS/LYMPHOMAS WAS DUE TO ABERRANT PROMOTER METHYLATION. THUS FAR, THE MECHANISM OF EPIGENETIC SILENCING OF THE SHP-1 TYROSINE PHOSPHATASE GENE THAT OCCURS IN CHRONIC MYELOGENOUS LEUKEMIA CELLS REMAINS POORLY UNDERSTOOD. METHODS: THE EXPRESSIONS OF THE TARGET MOLECULES WERE DETERMINED BY QUANTITATIVE REAL TIME PCR AND WESTERN BLOT, RESPECTIVELY. BISULFITE SEQUENCING PCR WAS USED TO DETECT METHYLATION STATUS OF DNA CPG. THE LENTIVIRAL VECTORS WERE APPLIED TO MODIFY GENE EXPRESSION. RESULTS: IN THE PRESENT STUDY, WE FOUND THAT THE PROMOTER 2 OF SHP-1 GENE IS LOCATED BETWEEN POSITIONS FROM -577BP TO +300BP, AND 22 CPG SITES CONTAINED IN POSITIONS -353BP APPROXIMATELY +182BP ARE ABERRANTLY METHYLATED IN K562 CELLS. IN VITRO, WE DEMONSTRATED THAT DNMT1 SILENCING INDUCED DEMETHYLATION OF THE 22 CPG SITES LOCATED IN THE SHP-1 PROMOTER AND RE-EXPRESSION OF SHP-1 GENE IN K562 CELLS. MOREOVER, WE PROVED THAT THE EXPRESSION LEVELS OF DNMT1 AND SHP-1 MRNA AND PROTEIN WERE NEGATIVELY CORRELATED IN K562 CELLS AND BM ASPIRATES MONONUCLEAR CELLS FROM CML PATIENTS. CONCLUSION: COLLECTIVELY, THESE RESULTS INDICATE THAT DNMT1 MEDIATES ABERRANT METHYLATION AND SILENCING OF SHP-1 GENE IN CHRONIC MYELOGENOUS LEUKEMIA CELLS, AND PROVIDE A NOVEL THERAPEUTIC TARGET FOR CML. 2017 2 6455 35 THYMOQUINONE ENHANCES APOPTOSIS OF K562 CHRONIC MYELOID LEUKEMIA CELLS THROUGH HYPOMETHYLATION OF SHP-1 AND INHIBITION OF JAK/STAT SIGNALING PATHWAY. THE EPIGENETIC SILENCING OF TUMOR SUPPRESSOR GENES (TSGS) IS CRITICAL IN THE DEVELOPMENT OF CHRONIC MYELOID LEUKEMIA (CML). SHP-1 FUNCTIONS AS A TSG AND NEGATIVELY REGULATES JAK/STAT SIGNALING. ENHANCEMENT OF SHP-1 EXPRESSION BY DEMETHYLATION PROVIDES MOLECULAR TARGETS FOR THE TREATMENT OF VARIOUS CANCERS. THYMOQUINONE (TQ), A CONSTITUENT OF NIGELLA SATIVA SEEDS, HAS SHOWN ANTI-CANCER ACTIVITIES IN VARIOUS CANCERS. HOWEVER, TQS EFFECT ON METHYLATION IS NOT FULLY CLEAR. THEREFORE, THE AIM OF THIS STUDY IS TO ASSESS TQS ABILITY TO ENHANCE THE EXPRESSION OF SHP-1 THROUGH MODIFYING DNA METHYLATION IN K562 CML CELLS. THE ACTIVITIES OF TQ ON CELL CYCLE PROGRESSION AND APOPTOSIS WERE EVALUATED USING A FLUOROMETRIC-RED CELL CYCLE ASSAY AND ANNEXIN V-FITC/PI, RESPECTIVELY. THE METHYLATION STATUS OF SHP-1 WAS STUDIED BY PYROSEQUENCING ANALYSIS. THE EXPRESSION OF SHP-1, TET2, WT1, DNMT1, DNMT3A, AND DNMT3B WAS DETERMINED USING RT-QPCR. THE PROTEIN PHOSPHORYLATION OF STAT3, STAT5, AND JAK2 WAS ASSESSED USING JESS WESTERN ANALYSIS. TQ SIGNIFICANTLY DOWNREGULATED THE DNMT1 GENE, DNMT3A GENE, AND DNMT3B GENE AND UPREGULATED THE WT1 GENE AND TET2 GENE. THIS LED TO HYPOMETHYLATION AND RESTORATION OF SHP-1 EXPRESSION, RESULTING IN INHIBITION OF JAK/STAT SIGNALING, INDUCTION OF APOPTOSIS, AND CELL CYCLE ARREST. THE OBSERVED FINDINGS IMPLY THAT TQ PROMOTES APOPTOSIS AND CELL CYCLE ARREST IN CML CELLS BY INHIBITING JAK/STAT SIGNALING VIA RESTORATION OF THE EXPRESSION OF JAK/STAT-NEGATIVE REGULATOR GENES. 2023 3 139 31 ABERRANT DNA METHYLATION IS ASSOCIATED WITH DISEASE PROGRESSION, RESISTANCE TO IMATINIB AND SHORTENED SURVIVAL IN CHRONIC MYELOGENOUS LEUKEMIA. THE EPIGENETIC IMPACT OF DNA METHYLATION IN CHRONIC MYELOGENOUS LEUKEMIA (CML) IS NOT COMPLETELY UNDERSTOOD. TO ELUCIDATE ITS ROLE WE ANALYZED 120 PATIENTS WITH CML FOR METHYLATION OF PROMOTER-ASSOCIATED CPG ISLANDS OF 10 GENES. FIVE GENES WERE IDENTIFIED BY DNA METHYLATION SCREENING IN THE K562 CELL LINE AND 3 GENES IN PATIENTS WITH MYELOPROLIFERATIVE NEOPLASMS. THE CDKN2B GENE WAS SELECTED FOR ITS FREQUENT METHYLATION IN MYELOID MALIGNANCIES AND ABL1 AS THE TARGET OF BCR-ABL TRANSLOCATION. THIRTY PATIENTS WERE IMATINIB-NAIVE (MOSTLY TREATED BY INTERFERON-ALPHA BEFORE THE IMATINIB ERA), 30 WERE IMATINIB-RESPONSIVE, 50 WERE IMATINIB-RESISTANT, AND 10 WERE IMATINIB-INTOLERANT. WE QUANTIFIED DNA METHYLATION BY BISULFITE PYROSEQUENCING. THE AVERAGE NUMBER OF METHYLATED GENES WAS 4.5 PER PATIENT IN THE CHRONIC PHASE, INCREASING SIGNIFICANTLY TO 6.2 IN THE ACCELERATED AND 6.4 IN THE BLASTIC PHASE. HIGHER NUMBERS OF METHYLATED GENES WERE ALSO OBSERVED IN PATIENTS RESISTANT OR INTOLERANT TO IMATINIB. THESE PATIENTS ALSO SHOWED ALMOST EXCLUSIVE METHYLATION OF A PUTATIVE TRANSPORTER OSCP1. ABNORMAL METHYLATION OF A SRC SUPPRESSOR GENE PDLIM4 WAS ASSOCIATED WITH SHORTENED SURVIVAL INDEPENDENTLY OF CML STAGE AND IMATINIB RESPONSIVENESS. WE CONCLUDE THAT ABERRANT DNA METHYLATION IS ASSOCIATED WITH CML PROGRESSION AND THAT DNA METHYLATION COULD BE A MARKER ASSOCIATED WITH IMATINIB RESISTANCE. FINALLY, DNA METHYLATION OF PDLIM4 MAY HELP IDENTIFY A SUBSET OF CML PATIENTS THAT WOULD BENEFIT FROM TREATMENT WITH SRC/ABL INHIBITORS. 2011 4 1733 39 E-CADHERIN GENE RE-EXPRESSION IN CHRONIC LYMPHOCYTIC LEUKEMIA CELLS BY HDAC INHIBITORS. BACKGROUND: THE TUMOR SUPPRESSOR GENE E-CADHERIN GENE IS FREQUENTLY SILENCED IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) CELLS AND RESULTS IN WNT-PATHWAY ACTIVATION. WE ANALYZED THE ROLE OF HISTONE EPIGENETIC MODIFICATIONS IN E-CADHERIN GENE SILENCING. METHODS: CLL SPECIMENS WERE TREATED WITH HISTONE DEACETYLASE INHIBITOR (HDACI) MS-275 AND ANALYZED FOR E-CADHERIN EXPRESSION WITH WESTERN BLOT AND RT-PCR ANALYSIS. THE DOWNSTREAM EFFECTS OF HDACI TREATED LEUKEMIC CELLS WERE STUDIED BY ANALYZING THE EFFECT ON WNT-PATHWAY SIGNALING. HDACI INDUCED ALTERATIONS IN E-CADHERIN SPLICING WERE INVESTIGATED BY TRANSCRIPT SPECIFIC REAL TIME PCR ANALYSIS. RESULTS: TREATMENT OF CLL SPECIMENS WITH HISTONE DEACETYLASE INHIBITORS (HDACI) TREATMENT RESULTED IN AN INCREASE OF THE E-CADHERIN RNA TRANSCRIPT (5 TO 119 FOLD INCREASE, N=10) IN EIGHT OUT OF TEN CLL SPECIMENS INDICATING THAT THIS GENE IS DOWN REGULATED BY HISTONE HYPOACETYLATION IN A MAJORITY OF CLL SPECIMENS. THE E-CADHERIN RE-EXPRESSION IN CLL SPECIMENS WAS NOTED BY WESTERN BLOT ANALYSIS AS WELL. BESIDES EPIGENETIC SILENCING ANOTHER MECHANISM OF E-CADHERIN INACTIVATION IS ABERRANT EXON 11 SPLICING RESULTING IN AN ALTERNATIVELY SPLICED TRANSCRIPT THAT LACKS EXON 11 AND IS DEGRADED BY THE NON-SENSE MEDIATED DECAY (NMD) PATHWAY. OUR CHROMATIN IMMUNOPRECIPITATION EXPERIMENTS SHOW THAT HDACI INCREASED THE ACETYLATION OF HISTONES H3 AND H4 IN THE E-CADHERIN PROMOTER REGION. THIS ALSO AFFECTED THE E-CADHERIN EXON 11 SPLICING PATTERN AS HDACI TREATED CLL SPECIMENS PREFERENTIALLY EXPRESSED THE CORRECTLY SPLICED TRANSCRIPT AND NOT THE EXON 11 SKIPPED ABERRANT TRANSCRIPT. THE RE-EXPRESSED E- CADHERIN BINDS TO BETA-CATENIN WITH INHIBITION OF THE ACTIVE WNT-BETA-CATENIN PATHWAY IN THESE CELLS. THIS RESULTED IN A DOWN REGULATION OF TWO WNT TARGET GENES, LEF AND CYCLIND1 AND THE WNT PATHWAY REPORTER. CONCLUSION: THE E-CADHERIN GENE IS EPIGENETICALLY MODIFIED AND HYPOACETYLATED IN CLL LEUKEMIC CELLS. TREATMENT OF CLL SPECIMENS WITH HDACI MS-275 ACTIVATES TRANSCRIPTION FROM THIS SILENT GENE WITH EXPRESSION OF MORE CORRECTLY SPLICED E-CADHERIN TRANSCRIPTS AS COMPARED TO THE ABERRANT EXON11 SKIPPED TRANSCRIPTS THAT IN TURN INHIBITS THE WNT SIGNALING PATHWAY. THE DATA HIGHLIGHTS THE ROLE OF EPIGENETIC MODIFICATIONS IN ALTERING GENE SPLICING PATTERNS. 2013 5 3531 36 IMATINIB CAUSES EPIGENETIC ALTERATIONS OF PTEN GENE VIA UPREGULATION OF DNA METHYLTRANSFERASES AND POLYCOMB GROUP PROTEINS. WE HAVE RECENTLY REPORTED THE POSSIBLE IMATINIB-RESISTANT MECHANISM; LONG-TERM EXPOSURE OF LEUKEMIA CELLS TO IMATINIB DOWNREGULATED LEVELS OF PHOSPHATASE AND TENSIN HOMOLOG DELETED ON CHROMOSOME 10 (PTEN) VIA HYPERMETHYLATION OF ITS PROMOTER REGION (LEUKEMIA 2010; 24: 1631). THE PRESENT STUDY EXPLORED THE MOLECULAR MECHANISMS BY WHICH IMATINIB CAUSED METHYLATION ON THE PROMOTER REGION OF THIS TUMOR SUPPRESSOR GENE IN LEUKEMIA CELLS. REAL-TIME REVERSE TRANSCRIPTION PCR FOUND THAT LONG-TERM EXPOSURE OF CHRONIC EOSINOPHILIC LEUKEMIA EOL-1 CELLS EXPRESSING FIP1L1/PLATELET-DERIVED GROWTH FACTOR RECEPTOR-ALPHA TO IMATINIB INDUCED EXPRESSION OF DNA METHYLTRANSFERASE 3A (DNMT3A) AND HISTONE-METHYLTRANSFERASE ENHANCER OF ZESTE HOMOLOG 2 (EZH2), A FAMILY OF POLYCOMB GROUP, THEREBY INCREASING METHYLATION OF THE GENE. IMMUNOPRECIPITATION ASSAY FOUND THE INCREASED COMPLEX FORMATION OF DNMT3A AND EZH2 PROTEINS IN THESE CELLS. MOREOVER, CHROMATIN IMMUNOPRECIPITATION ASSAY SHOWED THAT AMOUNTS OF BOTH DNMT3A AND EZH2 PROTEINS BOUND AROUND THE PROMOTER REGION OF PTEN GENE WERE INCREASED IN EOL-1 CELLS AFTER EXPOSURE TO IMATINIB. FURTHERMORE, WE FOUND THAT LEVELS OF DNMT3A AND EZH2 WERE STRIKINGLY INCREASED IN LEUKEMIA CELLS ISOLATED FROM INDIVIDUALS WITH CHRONIC MYELOGENOUS LEUKEMIA (N=1) AND PHILADELPHIA CHROMOSOME-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA (N=2), WHO RELAPSED AFTER TREATMENT WITH IMATINIB COMPARED WITH THOSE ISOLATED AT THEIR INITIAL PRESENTATION. TAKEN TOGETHER, IMATINIB COULD CAUSE DRUG-RESISTANCE VIA RECRUITMENT OF POLYCOMB GENE COMPLEX TO THE PROMOTER REGION OF THE PTEN AND DOWNREGULATION OF THIS GENE'S TRANSCRIPTS IN LEUKEMIA PATIENTS. 2011 6 3532 47 IMATINIB INDEPENDENT ABERRANT METHYLATION OF NOV/CCN3 IN CHRONIC MYELOGENOUS LEUKEMIA PATIENTS: A MECHANISM UPSTREAM OF BCR-ABL1 FUNCTION? BACKGROUND: THE NOV GENE PRODUCT, CCN3, HAS BEEN REPORTED IN A DIVERSE RANGE OF TUMORS TO SERVE AS A NEGATIVE GROWTH REGULATOR, WHILE ACTING AS A TUMOR SUPPRESSOR IN CHRONIC MYELOGENOUS LEUKEMIA (CML). HOWEVER, THE PRECISE MECHANISM OF ITS SILENCING IN CML IS POORLY UNDERSTOOD. IN THE CURRENT STUDY, WE AIMED TO QUERY IF THE GENE REGULATION OF CCN3 IS MEDIATED BY THE PROMOTER METHYLATION IN THE PATIENTS WITH CML. IN ADDITION, TO CLARIFY WHETHER THE EPIGENETIC SILENCING IS AFFECTED BY BCR-ABL1 INHIBITION, WE ASSESSED THE METHYLATION STATUS IN THE PATIENTS AT DIFFERENT TIME INTERVALS FOLLOWING THE TYROSINE KINASE INHIBITION USING IMATINIB THERAPY, AS THE FIRST-LINE TREATMENT FOR THIS TYPE OF LEUKEMIA. METHODS: TO ADDRESS THIS ISSUE, WE APPLIED BISULFITE-SEQUENCING TECHNIQUE AS A HIGH-RESOLUTION METHOD TO STUDY THE REGULATORY SEGMENT OF THE CCN3 GENE. THE RESULTS WERE ANALYZED IN NEWLY DIAGNOSED CML PATIENTS AS WELL AS FOLLOWING IMATINIB THERAPY. WE ALSO EVALUATED THE CORRELATION OF CCN3 PROMOTER METHYLATION WITH BCR-ABL1 LEVELS. RESULTS: OUR FINDINGS REVEALED THAT THE METHYLATION OCCURS FREQUENTLY IN THE PROMOTER REGION OF CML PATIENTS SHOWING A SIGNIFICANT INCREASE OF THE METHYLATED PERCENTAGE AT THE CPG SITES COMPARED TO NORMAL INDIVIDUALS. INTERESTINGLY, THIS HYPERMETHYLATION WAS INDICATED TO BE INDEPENDENT OF BCR-ABL1 TITERS IN BOTH GROUPS, WHICH MIGHT SUGGEST A MECHANISM BEYOND THE BCR-ABL1 FUNCTION. CONCLUSION: DESPITE SUGGESTING THAT THE CCN3 HYPERMETHYLATION ACTS AS A MOLECULAR MECHANISM INDEPENDENT OF BCR-ABL1 FUNCTION IN CML PATIENTS, THIS SCENARIO REQUIRES FURTHER VALIDATION BY COMPLEMENTARY EXPERIMENTS. IN THE CASE OF ACTING UPSTREAM OF BCR-ABL1 SIGNALING, THE METHYLATION MARKER CAN PROVIDE EARLY DETECTION AND A NOVEL PLATFORM FOR TARGETED EPIGENETIC MODIFIERS FOR EFFICIENT TREATMENT IN IMATINIB RESISTANT PATIENTS. 2019 7 1669 36 DOWNREGULATION OF THE HISTONE METHYLTRANSFERASE SETD2 PROMOTES IMATINIB RESISTANCE IN CHRONIC MYELOID LEUKAEMIA CELLS. OBJECTIVES: EPIGENETIC MODIFIERS WERE IMPORTANT PLAYERS IN THE DEVELOPMENT OF HAEMATOLOGICAL MALIGNANCIES AND SENSITIVITY TO THERAPY. MUTATIONS OF SET DOMAIN-CONTAINING 2 (SETD2), A METHYLTRANSFERASE THAT CATALYSES THE TRIMETHYLATION OF HISTONE 3 ON LYSINE 36 (H3K36ME3), WERE FOUND IN VARIOUS MYELOID MALIGNANCIES. HOWEVER, THE DETAILED MECHANISMS THROUGH WHICH SETD2 CONFERS CHRONIC MYELOID LEUKAEMIA PROGRESSION AND RESISTANCE TO THERAPY TARGETING ON BCR-ABL REMAIN UNCLEAR. MATERIALS AND METHODS: THE LEVEL OF SETD2 IN IMATINIB-SENSITIVE AND IMATINIB-RESISTANT CHRONIC MYELOID LEUKAEMIA (CML) CELLS WAS EXAMINED BY IMMUNOBLOTTING AND QUANTITATIVE REAL-TIME PCR. WE ANALYSED CD34(+) CD38(-) LEUKAEMIC STEM CELLS BY FLOW CYTOMETRY AND COLONY FORMATION ASSAYS UPON SETD2 KNOCKDOWN OR OVEREXPRESSION. THE IMPACT OF SETD2 EXPRESSION ALTERATIONS OR SMALL-MOLECULE INHIBITOR JIB-04 TARGETING H3K36ME3 LOSS ON IMATINIB SENSITIVITY WAS ASSESSED BY IC50, CELL APOPTOSIS AND PROLIFERATION ASSAYS. FINALLY, RNA SEQUENCING AND CHIP-QUANTITATIVE PCR WERE PERFORMED TO VERIFY PUTATIVE DOWNSTREAM TARGETS. RESULTS: SETD2 WAS FOUND TO ACT AS A TUMOUR SUPPRESSOR IN CML. THE NOVEL ONCOGENIC TARGETS MYCN AND ERG WERE SHOWN TO BE THE DIRECT DOWNSTREAM TARGETS OF SETD2, WHERE THEIR OVEREXPRESSION INDUCED BY SETD2 KNOCKDOWN CAUSED IMATINIB INSENSITIVITY AND LEUKAEMIC STEM CELL ENRICHMENT IN CML CELL LINES. TREATMENT WITH JIB-04, AN INHIBITOR THAT RESTORES H3K36ME3 LEVELS THROUGH BLOCKADE OF ITS DEMETHYLATION, SUCCESSFULLY IMPROVED THE CELL IMATINIB SENSITIVITY AND ENHANCED THE CHEMOTHERAPEUTIC EFFECT. CONCLUSIONS: OUR STUDY NOT ONLY EMPHASIZES THE REGULATORY MECHANISM OF SETD2 IN CML, BUT ALSO PROVIDES PROMISING THERAPEUTIC STRATEGIES FOR OVERCOMING THE IMATINIB RESISTANCE IN PATIENTS WITH CML. 2019 8 5669 25 SFRP1 PROMOTER METHYLATION IS ASSOCIATED WITH PERSISTENT PHILADELPHIA CHROMOSOME IN CHRONIC MYELOID LEUKEMIA. EPIGENETIC SILENCING OF SFRP GENES HAS BEEN SHOWN TO LEAD TO CONSTITUTIVE ACTIVATION OF THE CANONICAL WNT-SIGNALING PATHWAY. THE FIRST DESCRIPTION OF DEREGULATED WNT-SIGNALING ACTIVATION IN A HEMATOLOGICAL MALIGNANCY WAS REPORTED IN CHRONIC MYELOID LEUKEMIA (CML). TO INVESTIGATE WHETHER EPIGENETIC SILENCING OF SFRP IS RESPONSIBLE FOR THE OBSERVED WNT ACTIVATION IN CML, WE STUDIED THE METHYLATION AND MUTATIONAL STATUS OF THE SFRP1 PROMOTER IN 48 CHRONIC PHASE CML PATIENTS. OF THE 48 CML PATIENTS 41 WERE SHOWN TO BE UNMETHYLATED, 6 PATIENTS HEMI-METHYLATED AND 1 PATIENT FULLY METHYLATED AT THE SFRP1 PROMOTER. ALBEIT OBSERVED INFREQUENTLY IN CHRONIC PHASE CML, SFRP1 PROMOTER METHYLATION CORRELATED WITH PRIMARY CYTOGENETIC RESISTANCE TO IMATINIB MESYLATE. SFRP1 PROMOTER METHYLATION MAY INDICATE A GENETICALLY MORE UNSTABLE FORM OF DISEASE RESISTANT TO THERAPY AND PROVIDE A KEY BIOLOGICAL DIFFERENCE IN THERAPY RESISTANT PATIENTS, IN ADDITION TO A POSSIBLE MECHANISM FOR THE OBSERVED ACTIVATION OF CANONICAL WNT SIGNALING IN CML. 2009 9 3461 35 HYPOMETHYLATION-MEDIATED H19 OVEREXPRESSION INCREASES THE RISK OF DISEASE EVOLUTION THROUGH THE ASSOCIATION WITH BCR-ABL TRANSCRIPT IN CHRONIC MYELOID LEUKEMIA. PREVIOUS STUDY HAS REVEALED THAT H19 EXPRESSION IS REQUIRED FOR EFFICIENT TUMOR GROWTH INDUCED BY BCR-ABL IN CHRONIC MYELOID LEUKEMIA (CML). HEREIN, WE FURTHER DETERMINED H19 EXPRESSION AND ITS CLINICAL IMPLICATION IN PATIENTS WITH CML. H19 EXPRESSION AND METHYLATION WERE DETECTED BY REAL-TIME QUANTITATIVE PCR AND REAL-TIME QUANTITATIVE METHYLATION-SPECIFIC PCR, AND THEN CLINICAL IMPLICATION OF H19 EXPRESSION WAS FURTHER ANALYZED. H19 EXPRESSION WAS SIGNIFICANTLY UP-REGULATED IN CML PATIENTS (P < 0.001). H19 EXPRESSION WITH AN AREA UNDER RECEIVER OPERATING CHARACTERISTIC CURVE VALUE OF 0.824 MIGHT SERVE AS A PROMISING BIOMARKER IN DISTINGUISHING CML PATIENTS FROM CONTROLS. THE PATIENTS WITH HIGH H19 EXPRESSION HAD A TENDENCY OF HIGHER WHITE BLOOD CELLS AND BCR-ABL TRANSCRIPT THAN THOSE WITH LOW H19 EXPRESSION. H19 OVEREXPRESSION OCCURRED WITH THE HIGHER FREQUENCY IN BLAST CRISIS STAGE (11/11, 100%), LOWER IN ACCELERATED PHASE (3/5, 60%), AND CHRONIC PHASE (42/62, 66%) STAGES. MOREOVER, PAIRED PATIENTS DURING DISEASE PROGRESSION WITH INCREASED BCR-ABL TRANSCRIPT ALSO SHOWED A SIGNIFICANT UPREGULATION OF H19 EXPRESSION. MEANWHILE, H19 EXPRESSION WAS DECREASED IN FOLLOW-UP PATIENTS WHO ACHIEVED COMPLETE MOLECULAR REMISSION AFTER TYROSINE KINASE INHIBITORS-BASED THERAPY. EPIGENETIC STUDIES SHOWED THAT H19 DIFFERENTIALLY METHYLATED REGION/IMPRINTING CONTROL REGION (DMR/ICR) WAS HYPOMETHYLATED AND ASSOCIATED WITH H19 EXPRESSION IN CML PATIENTS. MOREOVER, DEMETHYLATION OF H19 DMR/ICR REACTIVATED H19 EXPRESSION IN K562 CELLS. COLLECTIVELY, H19 OVEREXPRESSION, A FREQUENT EVENT IN CML, WAS ASSOCIATED WITH HIGHER BCR-ABL TRANSCRIPT INVOLVING IN DISEASE PROGRESSION. MOREOVER, H19 DMR/ICR HYPOMETHYLATION IN CML MAY BE ONE OF THE MECHANISMS MEDIATING H19 OVEREXPRESSION. 2018 10 5458 40 RESEARCH ON EPIGENETIC MECHANISM OF SFRP2 IN ADVANCED CHRONIC MYELOID LEUKEMIA. SECRETED FRIZZLED-RELATED PROTEIN 2 (SFRP2) HAS BEEN REPORTED TO ACT AS A TUMOR SUPPRESSORS. THIS STUDY AIMS TO DETECT THE BIOLOGICAL ROLE OF SFRP2 IN ADVANCED CHRONIC MYELOID LEUKEMIA (CML). IN THIS STUDY WE EXAMINED BONE MARROW SAMPLES FROM 45 CML PATIENTS AND 10 HEALTHY DONORS. K562 AND KCL22 CELLS WERE CULTURED AND TREATED WITH DEMETHYLATION DRUG AND HISTONE DEACETYLASE INHIBITOR (HDACI). KCL22 AND K562 CELLS WERE TRANSFECTED WITH LENTIVIRAL VECTOR (LV)-SFRP2, LV-CONTROL. THE CELLS WERE THEN SUBJECTED TO PROLIFERATION AND APOPTOSIS ASSAYS, REAL TIME POLYMERASE CHAIN REACTION (PCR), METHYLATION-SPECIFIC PCR (MSP), WESTERN BLOTTING, CO-IMMUNOPRECIPITATION (COIP) AND CHROMATIN IMMUNOPRECIPITATION (CHIP), WE FOUND THAT SFRP2 WAS DOWN-REGULATED IN THE ACCELERATED AND BLAST PHASE OF CML, WHEREAS, THE LEVELS OF WNT1, WNT3 AND WNT5A WERE UP-REGULATED IN THE ACCELERATED AND BLAST PHASE OF CML. OVEREXPRESSION SFRP2 INHIBITED PROLIFERATION, PROMOTED APOPTOSIS AND ACTIVATED THE WNT PATHWAY. COIP-MS RESULTS SHOWED THAT SFRP2 INTERACTED WITH WNT1 AND WNT5A. CHIP-SEQ RESULT INDICATED THAT THE PROMOTER OF H3K4ME3 AND H3K27ME3 WERE ABLE TO INTERACT WITH SFRP2. IN CONCLUSION, OUR FINDINGS DEMONSTRATED THE SFRP2 ACT AS A POTENTIAL THERAPEUTIC TARGET FOR ADVANCED CML. FURTHERMORE, OUR RESULTS SUPPORT THE USE OF DEMETHYLATION DRUGS AND HDACI AS A POTENTIAL CML TREATMENT STRATEGY. 2018 11 4243 31 METHYLATION STATUS OF CEBPA GENE PROMOTER IN CHRONIC MYELOID LEUKEMIA. CCAAT/ENHANCER BINDING PROTEIN ALPHA IS ONE OF THE CRUCIAL TRANSCRIPTION FACTORS FOR MYELOID CELL DEVELOPMENT THAT HAS BEEN FOUND TO BE INVOLVED IN HEMATOPOIETIC DIFFERENTIATION AND LEUKEMIOGENESIS. RECENTLY, EPIGENETIC REGULATION OF CEBPA EXPRESSION THROUGH DNA METHYLATION HAS BEEN DEMONSTRATED IN LEUKEMIA. THE AIM OF THIS STUDY WAS TO INVESTIGATE THE METHYLATION STATUS OF CEBPA GENE IN CHRONIC MYELOID LEUKEMIA (CML) PATIENTS. THE METHYLATION STATUS OF CEBPA PROMOTER WAS STUDIED IN 100 PATIENTS WITH CML AND 98 NORMAL HEALTHY INDIVIDUALS FROM HYDERABAD, INDIA, USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. THE ABERRANT METHYLATION OF CEBPA GENE PROMOTER WAS FOUND IN 32 OF THE 100 CML CASES. A HIGHLY SIGNIFICANT ASSOCIATION WAS FOUND BETWEEN THE FREQUENCY OF CEBPA GENE PROMOTER HYPERMETHYLATION AND THE CML STAGES (P = 0.017), BUT ASSOCIATION WITH RESPECT TO AGE AND GENDER OF THE PATIENT WAS NOT FOUND. THE RESULTS SUGGEST THAT ABERRANT METHYLATION IN THE CPG ISLAND OF THE PROMOTER REGION OF THIS GENE MIGHT BE A COMMON EVENT IN CML, AND SYSTEMIC EXPRESSION STUDIES WILL BE NEEDED TO UNFOLD THE ROLE OF CEBPA PROMOTER METHYLATION IN THE DEVELOPMENT, PROGRESSION, AND PROGNOSIS OF CML. 2014 12 3444 36 HYPERMETHYLATION OF E-CADHERIN IN LEUKEMIA. E-CADHERIN GENE IS OFTEN TERMED A "METASTASIS SUPPRESSOR" GENE BECAUSE THE E-CADHERIN PROTEIN CAN SUPPRESS TUMOR CELL INVASION AND METASTASIS. INACTIVATION OF THE E-CADHERIN GENE OCCURS IN UNDIFFERENTIATED SOLID TUMORS BY BOTH GENETIC AND EPIGENETIC MECHANISMS; HOWEVER, THE ROLE OF E-CADHERIN IN HEMATOLOGIC MALIGNANCIES IS ONLY NOW BEING RECOGNIZED. E-CADHERIN EXPRESSION IS ESSENTIAL FOR ERYTHROBLAST AND NORMOBLAST MATURATION, YET EXPRESSION IS REDUCED OR ABSENT IN LEUKEMIC BLAST CELLS. THIS STUDY EXAMINED THE MESSENGER RNA (MRNA) AND PROTEIN EXPRESSION OF THE E-CADHERIN GENE IN BONE MARROW AND BLOOD SAMPLES FROM NORMAL DONORS AND PATIENTS WITH LEUKEMIA. WE FOUND THAT ALL NORMAL DONOR SAMPLES EXPRESSED E-CADHERIN MRNA, WHEREAS BOTH SAMPLES OF ACUTE MYELOGENOUS LEUKEMIA AND CHRONIC LYMPHOCYTIC LEUKEMIA HAD A SIGNIFICANT REDUCTION OR ABSENCE OF EXPRESSION. HOWEVER, NORMAL BLAST COUNTERPARTS EXPRESSED ONLY A LOW LEVEL OF E-CADHERIN SURFACE PROTEIN. SODIUM BISULPHITE GENOMIC SEQUENCING WAS USED TO FULLY CHARACTERIZE THE METHYLATION PATTERNS OF THE CPG ISLAND ASSOCIATED WITH THE E-CADHERIN GENE PROMOTER IN THOSE SAMPLES WITH MATCHED DNA. ALL OF THE NORMAL CONTROL SAMPLES WERE ESSENTIALLY UNMETHYLATED; HOWEVER, 14 OF 18 (78%) OF THE LEUKEMIA SAMPLES HAD ABNORMAL HYPERMETHYLATION OF THE E-CADHERIN CPG ISLAND. IN FACT BOTH ALLELES OF THE E-CADHERIN GENE WERE OFTEN HYPERMETHYLATED. WE CONCLUDE THE E-CADHERIN GENE IS A COMMON TARGET FOR HYPERMETHYLATION IN HEMATOLOGIC MALIGNANCIES. 2000 13 2081 37 EPIGENETIC DOWN-REGULATION OF BIM EXPRESSION IS ASSOCIATED WITH REDUCED OPTIMAL RESPONSES TO IMATINIB TREATMENT IN CHRONIC MYELOID LEUKAEMIA. BACKGROUND: EXPRESSION OF THE PRO-APOPTOTIC BCL-2-INTERACTING MEDIATOR (BIM) HAS RECENTLY BEEN IMPLICATED IN IMATINIB-INDUCED APOPTOSIS OF BCR-ABL1(+) CELLS. HOWEVER, THE MECHANISMS INVOLVED IN THE REGULATION OF BIM IN CML AND ITS ROLE IN THE CLINICAL SETTING HAVE NOT BEEN ESTABLISHED. DESIGN AND METHODS: WE ANALYSED THE MRNA EXPRESSION OF BIM IN 100 NEWLY DIAGNOSED PATIENTS WITH CML IN CHRONIC PHASE BY Q-RT-PCR AND THE PROTEIN LEVELS BY WESTERN BLOT ANALYSIS. METHYLATION STATUS WAS ANALYSED BY BISULPHITE GENOMIC SEQUENCING AND MSP. CML CELL LINES WERE TREATED WITH IMATINIB AND 5-AZA-2'-DEOXYCYTIDINE, AND WERE TRANSFECTED WITH TWO DIFFERENT SIRNAS AGAINST BIM AND CELL PROLIFERATION AND APOPTOSIS WERE ANALYSED. RESULTS: WE DEMONSTRATED THAT DOWN-REGULATION OF BIM EXPRESSION WAS PRESENT IN 36% OF THE PATIENTS AND WAS SIGNIFICANTLY ASSOCIATED WITH A LACK OF OPTIMAL RESPONSE TO IMATINIB AS INDICATED BY THE DECREASE IN CYTOGENETIC AND MOLECULAR RESPONSES AT 6, 12 AND 18 MONTHS IN COMPARISON WITH PATIENTS WITH NORMAL BIM EXPRESSION (P<0.05). EXPRESSION OF BIM WAS MEDIATED BY PROMOTER HYPERMETHYLATION AS DEMONSTRATED BY RESTORATION OF BIM EXPRESSION AFTER TREATMENT OF CML CELLS WITH 5-AZA-2'-DEOXYCYTIDINE. USING CML CELL LINES WITH LOW AND NORMAL EXPRESSION OF BIM WE FURTHER DEMONSTRATED THAT THE EXPRESSION OF BIM IS REQUIRED FOR IMATINIB-INDUCED CML APOPTOSIS. CONCLUSION: OUR DATA INDICATE THAT DOWN-REGULATION OF BIM IS EPIGENETICALLY CONTROLLED BY METHYLATION IN A PERCENTAGE OF CML PATIENTS AND HAS AN UNFAVOURABLE PROGNOSTIC IMPACT, AND THAT THE COMBINATION OF IMATINIB WITH A DE-METHYLATING AGENT MAY RESULT IN IMPROVED RESPONSES IN PATIENTS WITH DECREASED EXPRESSION OF BIM. 2009 14 3415 29 HSP90 INHIBITION INCREASES SOCS3 TRANSCRIPT AND REGULATES MIGRATION AND CELL DEATH IN CHRONIC LYMPHOCYTIC LEUKEMIA. EPIGENETIC OR TRANSCRIPTIONAL SILENCING OF IMPORTANT TUMOR SUPPRESSORS HAS BEEN DESCRIBED TO CONTRIBUTE TO CELL SURVIVAL AND TUMORIGENESIS IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). USING GENE EXPRESSION MICROARRAY ANALYSIS, WE FOUND THAT THOUSANDS OF GENES ARE REPRESSED MORE THAN 2-FOLD IN CLL COMPARED TO NORMAL B CELLS; HOWEVER THERAPEUTIC APPROACHES TO REVERSE THIS HAVE BEEN LIMITED IN CLL. FOLLOWING TREATMENT WITH THE HSP90 INHIBITOR 17-DMAG, A SIGNIFICANT NUMBER OF THESE REPRESSED GENES WERE SIGNIFICANTLY RE-EXPRESSED. ONE OF THE GENES SIGNIFICANTLY REPRESSED IN CLL AND UP-REGULATED BY 17-DMAG WAS SUPPRESSOR OF CYTOKINE SIGNALING 3, (SOCS3). SOCS3 HAS BEEN SHOWN TO BE SILENCED IN SOLID TUMORS AS WELL AS MYELOID LEUKEMIA; HOWEVER LITTLE IS KNOWN ABOUT THE REGULATION IN CLL. WE FOUND THAT 17-DMAG INDUCES EXPRESSION OF SOCS3 BY VIA THE ACTIVATION OF P38 SIGNALING, AND SUBSEQUENTLY INHIBITS AKT AND STAT3 PHOSPHORYLATION RESULTING IN DOWNSTREAM EFFECTS ON CELL MIGRATION AND SURVIVAL. WE THEREFORE SUGGEST THAT SOCS3 IS AN IMPORTANT SIGNALING PROTEIN IN CLL, AND HSP90 INHIBITORS REPRESENT A NOVEL APPROACH TO TARGET TRANSCRIPTIONAL REPRESSION IN B CELL LYMPHOPROLIFERATIVE DISORDERS WHICH EXHIBIT A SUBSTANTIAL DEGREE OF GENE REPRESSION. 2016 15 6238 39 THE MALIGNANCY SUPPRESSION ROLE OF MIR-23A BY TARGETING THE BCR/ABL ONCOGENE IN CHROMIC MYELOID LEUKEMIA. THE AIM OF THIS STUDY WAS TO INVESTIGATE THE ROLE AND MECHANISM OF MIR-23A IN THE REGULATION OF BCR/ABL AND TO PROVIDE A NEW PROGNOSTIC BIOMARKER FOR CHRONIC MYELOID LEUKEMIA (CML). THE EXPRESSION LEVELS OF MIR-23A AND BCR/ABL WERE ASSESSED IN 42 NEWLY DIAGNOSED CML PATIENTS, 37 CML PATIENTS IN FIRST COMPLETE REMISSION AND 25 HEALTHY CONTROLS. QUANTITATIVE REAL-TIME PCR, WESTERN BLOT ANALYSIS AND COLONY FORMATION ASSAY WERE USED TO EVALUATE CHANGES INDUCED BY OVEREXPRESSION OR INHIBITION OF MIR-23A OR BCR/ABL. MIR-23A MIMIC OR NEGATIVE CONTROL MIMIC WAS TRANSFECTED INTO A CML CELL LINE (K562) AND TWO LUNG CANCER CELL LINES (H157 AND SKMES1) USING LIPOFECTAMINE 2000, AND THE CELLS WERE USED FOR REAL-TIME REVERSE TRANSCRIPTION-PCR (RT-PCR) AND WESTERN BLOT ANALYSIS. WE FOUND THAT THE DOWNREGULATION OF MIR-23A EXPRESSION WAS A FREQUENT EVENT IN BOTH LEUKEMIA CELL LINES AND PRIMARY LEUKEMIC CELLS FROM PATIENTS WITH DE NOVO CML. THE MICROARRAY RESULTS SHOWED THAT MOST OF THE CML PATIENTS EXPRESSED HIGH LEVELS OF BCR/ABL AND LOW LEVELS OF MIR-23A. REAL-TIME RT-PCR AND WESTERN BLOT ANALYSIS SHOWED THAT THE BCR/ABL LEVELS IN MIR-23A-TRANSFECTED CELLS WERE LOWER THAN THOSE IN THE CONTROL GROUPS. ECTOPIC EXPRESSION OF MIR-23A IN K562 CELLS LED TO CELLULAR SENESCENCE. MOREOVER, WHEN K562 CELLS WERE TREATED WITH 5-AZA-2'-DEOXYCYTIDINE, A DNA METHYLATION INHIBITOR, BCR/ABL EXPRESSION WAS UPREGULATED, WHICH INDICATES EPIGENETIC SILENCING OF MIR-23A IN LEUKEMIC CELLS. BCR/ABL AND MIR-23A EXPRESSIONS WERE INVERSELY RELATED TO CML, AND BCR/ABL EXPRESSION WAS REGULATED BY MIR-23A IN LEUKEMIC CELLS. THE EPIGENETIC SILENCING OF MIR-23A LED TO DEREPRESSION OF BCR/ABL EXPRESSION, AND CONSEQUENTLY CONTRIBUTES TO CML DEVELOPMENT AND PROGRESSION. 2014 16 1968 31 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 17 206 29 ACTIVATION OF NOTCH AND MYC SIGNALING VIA B-CELL-RESTRICTED DEPLETION OF DNMT3A GENERATES A CONSISTENT MURINE MODEL OF CHRONIC LYMPHOCYTIC LEUKEMIA. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY DISORDERED DNA METHYLATION, SUGGESTING THESE EPIGENETIC CHANGES MIGHT PLAY A CRITICAL ROLE IN DISEASE ONSET AND PROGRESSION. THE METHYLTRANSFERASE DNMT3A IS A KEY REGULATOR OF DNA METHYLATION. ALTHOUGH DNMT3A SOMATIC MUTATIONS IN CLL ARE RARE, WE FOUND THAT LOW DNMT3A EXPRESSION IS ASSOCIATED WITH MORE AGGRESSIVE DISEASE. A CONDITIONAL KNOCKOUT MOUSE MODEL SHOWED THAT HOMOZYGOUS DEPLETION OF DNMT3A FROM B CELLS RESULTS IN THE DEVELOPMENT OF CLL WITH 100% PENETRANCE AT A MEDIAN AGE OF ONSET OF 5.3 MONTHS, AND HETEROZYGOUS DNMT3A DEPLETION YIELDS A DISEASE PENETRANCE OF 89% WITH A MEDIAN ONSET AT 18.5 MONTHS, CONFIRMING ITS ROLE AS A HAPLOINSUFFICIENT TUMOR SUPPRESSOR. B1A CELLS WERE CONFIRMED AS THE CELL OF ORIGIN OF DISEASE IN THIS MODEL, AND DNMT3A DEPLETION RESULTED IN FOCAL HYPOMETHYLATION AND ACTIVATION OF NOTCH AND MYC SIGNALING. AMPLIFICATION OF CHROMOSOME 15 CONTAINING THE MYC GENE WAS DETECTED IN ALL CLL MICE TESTED, AND INFILTRATION OF HIGH-MYC-EXPRESSING CLL CELLS IN THE SPLEEN WAS OBSERVED. NOTABLY, HYPERACTIVATION OF NOTCH AND MYC SIGNALING WAS EXCLUSIVELY OBSERVED IN THE DNMT3A CLL MICE, BUT NOT IN THREE OTHER CLL MOUSE MODELS TESTED (SF3B1-ATM, IKZF3, AND MDR), AND DNMT3A-DEPLETED CLL WERE SENSITIVE TO PHARMACOLOGIC INHIBITION OF NOTCH SIGNALING IN VITRO AND IN VIVO. CONSISTENT WITH THESE FINDINGS, HUMAN CLL SAMPLES WITH LOWER DNMT3A EXPRESSION WERE MORE SENSITIVE TO NOTCH INHIBITION THAN THOSE WITH HIGHER DNMT3A EXPRESSION. ALTOGETHER, THESE RESULTS SUGGEST THAT DNMT3A DEPLETION INDUCES CLL THAT IS HIGHLY DEPENDENT ON ACTIVATION OF NOTCH AND MYC SIGNALING. SIGNIFICANCE: LOSS OF DNMT3A EXPRESSION IS A DRIVING EVENT IN CLL AND IS ASSOCIATED WITH AGGRESSIVE DISEASE, ACTIVATION OF NOTCH AND MYC SIGNALING, AND ENHANCED SENSITIVITY TO NOTCH INHIBITION. 2021 18 4877 40 OVEREXPRESSION OF MIR-4433 BY SUBEROYLANILIDE HYDROXAMIC ACID SUPPRESSES GROWTH OF CML CELLS AND INDUCES APOPTOSIS THROUGH TARGETING BCR-ABL. BACKGROUND: TARGETING BCR-ABL IS THE KEY FOR THE TREATMENT OF CML. ALTHOUGH GREAT PROGRESS HAS BEEN ACHIEVED FOR THE TREATMENT OF CML PATIENTS IN CHRONIC STAGE, EFFECTIVE DRUGS WITH GOOD SAFETY ARE NOT AVAILABLE FOR THOSE IN ADVANCED STAGES OF CML PATIENTS. IN PRESENT STUDY, A HISTONE DEACETYLASE INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), WAS USED TO SCREEN FOR MICRORNA THAT CAN TARGET BCR-ABL. METHODS: RT-QPCR WAS USED TO DETERMINE BCR-ABL AND MIR-4433 TRANSCRIPTION LEVEL IN CML CELLS. IN CML CELLS, PROTEINS INCLUDING PARP, CASPASE-3, ACETYL-HISTONE 3, HISTONE 3 AND BCR-ABL, AS WELL AS BCR-ABL DOWNSTREAM PROTEINS WERE DETECTED USING WESTERN BLOT. CELL VIABILITY AND APOPTOSIS WERE MONITORED RESPECTIVELY BY MTS ASSAY AND FLOW CYTOMETRY. THE CORRELATION BETWEEN MIR-4433 AND BCR-ABL WAS DETERMINED BY LUCIFERASE REPORTER ASSAY. THE ANTI-TUMOR EFFECT OF MIR-4433 TO K562 CELLS WAS EVALUATED BY NUDE MOUSE XENOGRAFT MODEL IN VIVO. RESULTS: SAHA UP-REGULATED THE ACETYLATION LEVEL OF HISTONE 3, AND EFFECTIVELY INHIBITED BCR-ABL MRNA LEVEL AND ITS DOWNSTREAM SIGNAL TRANSDUCTION PATHWAY, WHILE INHIBITING THE GROWTH OF CML CELLS AND INDUCING APOPTOSIS. FURTHERMORE, BIOINFORMATICS TOOLS PREDICTED THAT MIR-4433 IS A PUTATIVE MICRORNA TARGETING BCR-ABL AND THAT THE EXPRESSION LEVEL OF MIR-4433 WAS SIGNIFICANTLY INCREASED AFTER SAHA TREATMENT IN K562 CELLS. LUCIFERASE ACTIVITY ANALYSIS REVEALED THAT MIR-4433 DIRECTLY TARGETS BCR-ABL. ADDITIONALLY, TRANSIENT EXPRESSION OF MIR-4433 ABROGATED BCR-ABL ACTIVITY AND ITS DOWNSTREAM SIGNALING PATHWAYS WHILE INDUCING APOPTOSIS IN K562 CELLS. MOREOVER, STABLE EXPRESSION OF MIR-4433 SUPPRESSED BCR-ABL AND ITS DOWNSTREAM SIGNALING PATHWAY, AND INHIBITED THE GROWTH OF K562 CELLS IN VITRO AND THE GROWTH OF K562-XENOGRAFTS IN NUDE MICE. CONCLUSION: MIR-4433 WAS IDENTIFIED AS A MICRORNA TARGETING BCR-ABL, WHICH MAY BE SUBJECT TO EPIGENETIC REGULATION OF SAHA, A HISTONE DEACETYLASE INHIBITOR THAT HAS BEEN APPROVED BY THE US FDA FOR THE TREATMENT OF CUTANEOUS T-CELL LYMPHOMA. THE FINDINGS OF THIS STUDY PROVIDE A MOLECULAR BASIS FROM ANOTHER ANGLE FOR THE USE OF SAHA IN THE TREATMENT OF CML. 2019 19 3062 38 GENOME-WIDE DNA METHYLATION ANALYSIS REVEALS NOVEL EPIGENETIC CHANGES IN CHRONIC LYMPHOCYTIC LEUKEMIA. WE CONDUCTED A GENOME-WIDE DNA METHYLATION ANALYSIS IN CD19 (+) B-CELLS FROM CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) PATIENTS AND NORMAL CONTROL SAMPLES USING REDUCED REPRESENTATION BISULFITE SEQUENCING (RRBS). THE METHYLATION STATUS OF 1.8-2.3 MILLION CPGS IN THE CLL GENOME WAS DETERMINED; ABOUT 45% OF THESE CPGS WERE LOCATED IN MORE THAN 23,000 CPG ISLANDS (CGIS). WHILE GLOBAL CPG METHYLATION WAS SIMILAR BETWEEN CLL AND NORMAL B-CELLS, 1764 GENE PROMOTERS WERE IDENTIFIED AS BEING DIFFERENTIALLY METHYLATED IN AT LEAST ONE CLL SAMPLE WHEN COMPARED WITH NORMAL B-CELL SAMPLES. NINETEEN PERCENT OF THE DIFFERENTIALLY METHYLATED GENES WERE INVOLVED IN TRANSCRIPTIONAL REGULATION. ABERRANT HYPERMETHYLATION WAS FOUND IN ALL HOX GENE CLUSTERS AND A SIGNIFICANT NUMBER OF WNT SIGNALING PATHWAY GENES. HYPOMETHYLATION OCCURRED MORE FREQUENTLY IN THE GENE BODY INCLUDING INTRONS, EXONS, AND 3'-UTRS IN CLL. THE NFATC1 P2 PROMOTER AND FIRST INTRON WAS FOUND TO BE HYPOMETHYLATED AND CORRELATED WITH UPREGULATION OF BOTH NFATC1 RNA AND PROTEIN EXPRESSION LEVELS IN CLL SUGGESTING THAT AN EPIGENETIC MECHANISM IS INVOLVED IN THE CONSTITUTIVE ACTIVATION OF NFAT ACTIVITY IN CLL CELLS. THIS COMPREHENSIVE DNA METHYLATION ANALYSIS WILL FURTHER OUR UNDERSTANDING OF THE EPIGENETIC CONTRIBUTION TO CELLULAR DYSFUNCTION IN CLL. 2012 20 149 34 ABERRANT HYDROXYMETHYLATION IN PROMOTER CPG REGIONS OF GENES RELATED TO THE CELL CYCLE AND APOPTOSIS CHARACTERIZES ADVANCED CHRONIC MYELOID LEUKEMIA DISEASE, POOR IMATINIB RESPONDENTS AND POOR SURVIVAL. BACKGROUND: THERE IS STRONG EVIDENCE THAT DISEASE PROGRESSION, DRUG RESPONSE AND OVERALL CLINICAL OUTCOMES OF CML DISEASE ARE NOT ONLY DECIDED BY BCR/ABL1 ONCOPROTEIN BUT DEPEND ON ACCUMULATION OF ADDITIONAL GENETIC AND EPIGENETIC ABERRATIONS. DNA HYDROXYMETHYLATION IS IMPLICATED IN THE DEVELOPMENT OF VARIETY OF DISEASES. DNA HYDROXYMETHYLATION IN GENE PROMOTERS PLAYS IMPORTANT ROLES IN DISEASE PROGRESSION, DRUG RESPONSE AND CLINICAL OUTCOME OF VARIOUS DISEASES. THEREFORE IN THIS STUDY, WE AIMED TO EXPLORE THE ROLE OF ABERRANT HYDROXYMETHYLATION IN PROMOTER REGIONS OF DIFFERENT TUMOR SUPPRESSOR GENES IN RELATION TO CML DISEASE PROGRESSION, RESPONSE TO IMATINIB THERAPY AND CLINICAL OUTCOME. METHODS: WE RECRUITED 150 CML PATIENTS AT DIFFERENT CLINICAL STAGES OF THE DISEASE. PATIENTS WERE FOLLOWED UP FOR 48 MONTHS AND HAEMATOLOGICAL/MOLECULAR RESPONSES WERE ANALYSED. HAEMATOLOGICAL RESPONSE WAS ANALYSED BY PERIPHERAL BLOOD SMEAR. BCR/ABL1 SPECIFIC TAQMAN PROBE BASED QRT-PCR WAS USED FOR ASSESSING THE MOLECULAR RESPONSE OF CML PATIENTS ON IMATINIB THERAPY. PROMOTER HYDROXYMETHYLATION OF THE GENES WAS CHARACTERIZED USING MS-PCR. RESULTS: WE OBSERVED THAT PROMOTER HYDROXYMETHYLATION OF DAPK1, RIZ1, P16INK4A, RASSF1A AND P14ARF(ARF) GENES CHARACTERIZE ADVANCED CML DISEASE AND POOR IMATINIB RESPONDENTS. ALTHOUGH, CYTOKINE SIGNALLING (SOCS1) GENE WAS HYPERMETHYLATED IN ADVANCED STAGES OF CML AND ACCUMULATED IN PATIENTS WITH POOR IMATINIB RESPONSE, BUT THE DIFFERENCES WERE NOT STATISTICALLY SIGNIFICANT. MOREOVER, WE FOUND HYPERMETHYLATION OF P14(ARF), RASSF1 AND P16(INK4A) GENES AND CYTOKINE SIGNALLING GENE (SOCS1) SIGNIFICANTLY ASSOCIATED WITH POOR OVERALL SURVIVAL OF CML PATIENTS ON IMATINIB THERAPY. THE RESULTS OF THIS STUDY ARE IN AGREEMENT OF THE ROLE OF ABERRANT DNA METHYLATION OF DIFFERENT TUMOR SUPPRESSOR GENES AS POTENTIAL BIOMARKERS OF CML DISEASE PROGRESSION, POOR IMATINIB RESPONSE AND OVERALL CLINICAL OUTCOME. CONCLUSION: IN THIS STUDY, WE REPORT THAT PROMOTER HYDROXYMETHYLATION OF DAPK1, RIZ1, P16INK4A, RASSF1A AND P14ARF(ARF) GENES IS A CHARACTERISTIC FEATURE OF CML DISEASE PROGRESSIONS, DEFINES POOR IMATINIB RESPONDENTS AND POOR OVERALL SURVIVAL OF CML PATIENTS TO IMATINIB THERAPY. 2022