1 205 82 ACTIVATION OF HLA-G EXPRESSION BY 5-AZA-2 - DEOXYCYTIDINE IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM LEUKEMIA PATIENTS. HUMAN LEUKOCYTE ANTIGEN - G (HLA-G) IS A NON-CLASSICAL HLA CLASS I ANTIGEN WITH RESTRICTED DISTRIBUTION IN NORMAL TISSUES. ECTOPIC HLA-G EXPRESSION OBSERVED AT SOME PATHOLOGICAL CIRCUMSTANCES AS MALIGNANT TRANSFORMATION MIGHT BE TRIGGERED BY EPIGENETIC MODIFICATIONS SUCH AS DNA DEMETHYLATION. RECENTLY IT WAS DEMONSTRATED THAT DNA METHYLTRANSFERASE INHIBITOR 5-AZA-2 - DEOXYCYTIDINE (ADC) INDUCES/ENHANCES HLA-G TRANSCRIPTION IN MANY LEUKEMIA CELL LINES OF DIFFERENT ORIGIN. HERE WE INVESTIGATED THE EFFECT OF ADC ON HLA-G EXPRESSION IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM PATIENTS WITH ACUTE MYELOID LEUKEMIA (AML) AND CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL). WE DETECTED HLA-G EXPRESSION IN UNTREATED CELLS FROM SOME PATIENTS. NEVERTHELESS TREATMENT WITH 5-AZA-2 - DEOXYCYTIDINE ENHANCED HLA-G TRANSCRIPTION AND CONCOMITANTLY HLA-G PROTEIN SYNTHESIS IN SOME LEUKEMIA CELLS. 2009 2 1657 24 DOWN-EXPRESSION OF MIR-152 LEAD TO IMPAIRED ANTI-TUMOR EFFECT OF NK VIA UPREGULATION OF HLA-G. IT IS KNOWN THAT CHRONIC HBV INFECTION (CHB) IS THE MAJOR RISK FACTOR FOR HEPATOCELLULAR CARCINOMA (HCC) BECAUSE CHB COULD NOT ONLY CAUSE LIVER TUMORIGENESIS BUT ALSO LEAD TO CHANGE OF LOCAL MICROENVIROMENT AND LOWER IMMUNE RESPONSE TO INFECTED AND CANCEROUS CELLS (IMMUNE TOLERANCE). HUMAN LEUCOCYTE ANTIGEN-G (HLA-G) BELONGS TO A NON-CLASSIC MHC-I FAMILY AND WAS CONSIDERED TO BE AN IMMUNE TOLERANCE MOLECULE, WHICH COULD BIND TO IMMUNOSUPPRESSIVE RECEPTORS OF NATURAL KILLER CELL (NK) AND T CELLS AND TRIGGER IMMUNOSUPPRESSIVE SIGNALING. RECENTLY, NUMEROUS STUDIES HIGHLIGHTED THAT MICRORNAS (MIRNAS) WERE SIGNIFICANTLY DIFFERENTIALLY EXPRESSED IN HCC TUMORIGENESIS, AND THE EXPRESSION WAS TISSUE-SPECIFIC, INDICATING THAT MIRNAS MAY CAUSE GREAT EPIGENETIC CHANGES IN HCC TUMORIGENESIS. IN THIS STUDY, WE FOUND THAT THE EXPRESSION OF HLA-G WAS UPREGULATED BY HEPATITIS B VIRUS (HBV) INFECTION AND MIR-152; A HLA-G-TARGETING MIRNA WAS DOWNREGULATED BY HBV INFECTION. AND HIGH EXPRESSION OF HLA-G FURTHER SUPPRESSED NK AGAINST CANCER CELLS, PROVIDING A NEW CONCEPT THAT MIR-152 WAS INVOLVED IN HBV-INDUCED HEPATOCELLULAR CARCINOMA. 2016 3 1211 27 CPG ISLAND METHYLATION AND EXPRESSION OF THE SECRETED FRIZZLED-RELATED PROTEIN GENE FAMILY IN CHRONIC LYMPHOCYTIC LEUKEMIA. B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY A CLONAL ACCUMULATION OF MATURE NEOPLASTIC B CELLS INDICATING DISRUPTION OF APOPTOSIS. RESTRICTION LANDMARK GENOME SCANNING WAS DONE TO IDENTIFY NOVEL TARGET GENES SILENCED BY CPG ISLAND METHYLATION IN CLL. SECRETED FRIZZLED-RELATED PROTEIN 4 (SFRP4), A NEGATIVE REGULATOR OF THE WNT SIGNALING PATHWAY, WAS FOUND TO BE FREQUENTLY METHYLATED IN CLL SAMPLES. WNT SIGNALING HAS BEEN SHOWN TO CONTROL NORMAL APOPTOTIC BEHAVIOR AND IS REQUIRED FOR NORMAL B-CELL DEVELOPMENT WHEREAS ABERRANT ACTIVATION OF THIS PATHWAY HAS BEEN OBSERVED IN CLL. WE SHOW ABERRANT DNA METHYLATION AND SILENCING OF SFRP4, AS WELL AS OF ADDITIONAL SFRP FAMILY MEMBERS, IN PRIMARY CLL SAMPLES. INDUCTION OF THEIR EXPRESSION IN A DOSE-DEPENDENT MANNER FOLLOWING TREATMENT WITH A DEMETHYLATING AGENT, 5-AZA-2'-DEOXYCYTIDINE, WAS SHOWN. OF THE FIVE SFRP FAMILY MEMBERS STUDIED IN DETAIL, SFRP1 WAS HYPERMETHYLATED AND DOWN-REGULATED IN ALL CLL PATIENT SAMPLES STUDIED, SUGGESTING THAT THIS EPIGENETIC EVENT IS A CRITICAL STEP DURING LEUKEMOGENESIS. OUR RESULTS SUGGEST THAT SILENCING OF SFRPS BY CPG ISLAND METHYLATION IS ONE POSSIBLE MECHANISM CONTRIBUTING TO ABERRANT ACTIVATION OF WNT SIGNALING PATHWAY IN CLL. 2006 4 1146 36 CONCURRENT EPIGENETIC SILENCING OF WNT/BETA-CATENIN PATHWAY INHIBITOR GENES IN B CELL CHRONIC LYMPHOCYTIC LEUKAEMIA. BACKGROUND: THE WNT/BETA-CATENIN SIGNALLING IS ABERRANTLY ACTIVATED IN PRIMARY B CELL CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL). EPIGENETIC SILENCING OF PATHWAY INHIBITOR GENES MAY BE A MECHANISM FOR ITS ACTIVATION. IN THIS STUDY, WE INVESTIGATED SYSTEMATICALLY AND QUANTITATIVELY THE METHYLATION STATUS OF 12 WNT/BETA-CATENIN PATHWAY INHIBITOR GENES - CDH1, DACT1, DKK1, DKK2, DKK3, DKK4, SFRP1, SFRP2, SFRP3, SFRP4, SFRP5 AND WIF1 - IN THE CELL LINES EHEB AND MEC-1 AS WELL AS PATIENT SAMPLES. METHODS: QUANTIFICATION OF DNA METHYLATION WAS PERFORMED BY MEANS OF BISULPHITE PYROSEQUENCING AND CONFIRMED BY BISULPHITE SANGER SEQUENCING. GENE EXPRESSION WAS ANALYSED BY QPCR USING GAPDH AS INTERNAL CONTROL. E-CADHERIN AND BETA-CATENIN PROTEIN QUANTIFICATION WAS CARRIED OUT BY MICROSPHERE-BASED IMMUNOASSAYS. METHYLATION DIFFERENCES OBSERVED BETWEEN THE PATIENT AND CONTROL GROUPS WERE TESTED USING GENERALISED LEAST SQUARES MODELS. RESULTS: FOR 10 GENES, A HIGHER METHYLATION LEVEL WAS OBSERVED IN TUMOUR MATERIAL. ONLY DKK4 EXHIBITED SIMILARLY HIGH METHYLATION LEVELS IN BOTH TUMOUR AND NORMAL SPECIMENS, WHILE DACT1 WAS ALWAYS ESSENTIALLY UNMETHYLATED. HOWEVER, ALSO FOR THESE INHIBITORS, TREATMENT OF CELLS WITH THE DEMETHYLATING AGENT 5-AZA-2 -DEOXYCYTIDINE RESULTED IN AN INDUCTION OF THEIR EXPRESSION, AS SHOWN BY QUANTITATIVE PCR, SUGGESTING AN INDIRECT EPIGENETIC CONTROL OF ACTIVITY. WHILE THE DEGREE OF DEMETHYLATION AND ITS TRANSCRIPTIONAL CONSEQUENCES DIFFERED BETWEEN THE GENES, THERE WAS AN OVERALL HIGH CORRELATION OF DEMETHYLATION AND INCREASED ACTIVITY. PROTEIN EXPRESSION STUDIES REVEALED THAT NO CONSTITUTIVE WNT/BETA-CATENIN SIGNALLING OCCURRED IN THE CELL LINES, WHICH IS IN DISCREPANCY WITH RESULTS FROM PRIMARY CLL. HOWEVER, TREATMENT WITH 5-AZA-2 -DEOXYCYTIDINE CAUSED ACCUMULATION OF BETA-CATENIN. SIMULTANEOUSLY, E-CADHERIN EXPRESSION WAS STRONGLY INDUCED, LEADING TO THE FORMATION OF A COMPLEX WITH BETA-CATENIN AND THUS DEMONSTRATING ITS EPIGENETICALLY REGULATED INHIBITION EFFECT. CONCLUSIONS: THE RESULTS SUGGEST AN EPIGENETIC SILENCING MECHANISM OF THE WNT/BETA-CATENIN PATHWAY INHIBITOR GENES IN CLL. HYPERMETHYLATION AND SILENCING OF FUNCTIONALLY RELATED GENES MAY NOT BE COMPLETELY STOCHASTIC BUT RESULT FROM THE TUMOUR EPIGENOME REPROGRAMMING ORCHESTRATED BY POLYCOMB-GROUP REPRESSIVE COMPLEXES. THE DATA ARE OF INTEREST IN THE CONTEXT OF EPIGENETIC-BASED THERAPY. 2012 5 3444 25 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 6 206 32 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 7 3415 28 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 8 2971 23 GENETIC AND EPIGENETIC SILENCING OF MICRORNA-203 ENHANCES ABL1 AND BCR-ABL1 ONCOGENE EXPRESSION. THE MAMMALIAN GENOME CONTAINS SEVERAL HUNDRED MICRORNAS THAT REGULATE GENE EXPRESSION THROUGH MODULATION OF TARGET MRNAS. HERE, WE REPORT A FRAGILE CHROMOSOMAL REGION LOST IN SPECIFIC HEMATOPOIETIC MALIGNANCIES. THIS 7 MB REGION ENCODES ABOUT 12% OF ALL GENOMIC MICRORNAS, INCLUDING MIR-203. THIS MICRORNA IS ADDITIONALLY HYPERMETHYLATED IN SEVERAL HEMATOPOIETIC TUMORS, INCLUDING CHRONIC MYELOGENOUS LEUKEMIAS AND SOME ACUTE LYMPHOBLASTIC LEUKEMIAS. A PUTATIVE MIR-203 TARGET, ABL1, IS SPECIFICALLY ACTIVATED IN THESE HEMATOPOIETIC MALIGNANCIES IN SOME CASES AS A BCR-ABL1 FUSION PROTEIN (PHILADELPHIA CHROMOSOME). RE-EXPRESSION OF MIR-203 REDUCES ABL1 AND BCR-ABL1 FUSION PROTEIN LEVELS AND INHIBITS TUMOR CELL PROLIFERATION IN AN ABL1-DEPENDENT MANNER. THUS, MIR-203 FUNCTIONS AS A TUMOR SUPPRESSOR, AND RE-EXPRESSION OF THIS MICRORNA MIGHT HAVE THERAPEUTIC BENEFITS IN SPECIFIC HEMATOPOIETIC MALIGNANCIES. 2008 9 6529 30 TRANSCRIPTIONAL DOWN-REGULATION OF THE WNT ANTAGONIST SFRP1 IN HAEMATOPOIETIC CELLS OF PATIENTS WITH DIFFERENT RISK TYPES OF MDS. SECRETED FRIZZLED RELATED PROTEIN 1 (SFRP1) IS AN EXTRACELLULAR ANTAGONIST OF THE WNT SIGNALLING PATHWAY THAT PLAYS AN IMPORTANT ROLE IN THE PATHOGENESIS OF SOLID TUMOURS AND HAEMATOPOIETIC MALIGNANCIES. SFRP1 HAS BEEN OBSERVED TO BE TRANSCRIPTIONALLY DOWN-REGULATED DUE TO HYPERMETHYLATION IN ACUTE AND CHRONIC LEUKAEMIA, BUT SO FAR NOT IN MYELODYSPLASTIC SYNDROME (MDS). MOREOVER, IT HAS BEEN SHOWN THAT THE EPIGENETIC INACTIVATION OF SFRP1 CORRELATES WITH AN OVEREXPRESSION OF THE WNT RECEPTOR FRIZZLED 3 (FZD3) IN ACUTE LEUKAEMIA. USING REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION (RT-PCR) WE EXAMINED MRNA EXPRESSION OF SFRP1 AND FZD3 IN BONE MARROW CELLS DERIVED FROM 121 PATIENTS WITH DIFFERENT RISK TYPES OF MDS, ACUTE MYELOID LEUKAEMIA (AML) AND ACUTE LYMPHOBLASTIC LEUKAEMIA (ALL). WE EMPLOYED PYROSEQUENCING TO QUANTIFY PROMOTER DNA METHYLATION IN MDS AND ACUTE LEUKAEMIA. WE DETECTED SIGNIFICANT LOWER MRNA TRANSCRIPTION OF SFRP1 IN MDS COMPARED TO HEALTHY INDIVIDUALS. HOWEVER, DNA SEQUENCE MUTATIONS OR FREQUENT ELEVATED DNA METHYLATION LEVELS OF THE SFRP1 PROMOTER COULD NOT BE OBSERVED IN MDS BUT IN AML AND ALL AS PREVIOUSLY REPORTED. THE EXPRESSION LEVELS OF FZD3 WERE UP-REGULATED IN BOTH ACUTE LEUKAEMIA AND MDS. OUR DATA SHOW A SIGNIFICANT TRANSCRIPTIONAL DOWN-REGULATION OF SFRP1 AS A COMMON EVENT IN AML, ALL AND - AS DEMONSTRATED FOR THE FIRST TIME - IN MDS. AN INACTIVATION OF SFRP1 AND THE TRANSCRIPTIONAL UP-REGULATION OF FZD3 SEEM TO BE ASSOCIATED WITH AN ACTIVATION OF THE WNT SIGNALLING PATHWAY IN THESE HAEMATOPOIETIC DISEASES. 2010 10 825 23 CHARACTERIZATION OF FUNCTIONAL TRANSPOSABLE ELEMENT ENHANCERS IN ACUTE MYELOID LEUKEMIA. TRANSPOSABLE ELEMENTS (TES) HAVE BEEN SHOWN TO HAVE IMPORTANT GENE REGULATORY FUNCTIONS AND THEIR ALTERATION COULD LEAD TO DISEASE PHENOTYPES. ACUTE MYELOID LEUKEMIA (AML) DEVELOPS AS A CONSEQUENCE OF A SERIES OF GENETIC CHANGES IN HEMATOPOIETIC PRECURSOR CELLS, INCLUDING MUTATIONS IN EPIGENETIC FACTORS. HERE, WE SET OUT TO STUDY THE GENE REGULATORY ROLE OF TES IN AML. WE FIRST EXPLORED THE EPIGENETIC LANDSCAPE OF TES IN AML PATIENTS USING ATAC-SEQ DATA. WE SHOW THAT A LARGE NUMBER OF TES IN GENERAL, AND MORE SPECIFICALLY MAMMALIAN-WIDE INTERSPERSED REPEATS (MIRS), ARE MORE ENRICHED IN AML CELLS THAN IN NORMAL BLOOD CELLS. WE OBTAINED A SIMILAR FINDING WHEN ANALYZING HISTONE MODIFICATION DATA IN AML PATIENTS. GENE ONTOLOGY ENRICHMENT ANALYSIS SHOWED THAT GENES NEAR MIRS IN OPEN CHROMATIN REGIONS ARE INVOLVED IN LEUKEMOGENESIS. TO FUNCTIONALLY VALIDATE THEIR REGULATORY ROLE, WE SELECTED 19 MIR REGIONS IN AML CELLS, AND TESTED THEM FOR ENHANCER ACTIVITY IN AN AML CELL LINE (KASUMI-1) AND A CHRONIC MYELOID LEUKEMIA (CML) CELL LINE (K562); THE RESULTS REVEALED SEVERAL MIRS TO BE FUNCTIONAL ENHANCERS. TAKEN TOGETHER, OUR RESULTS SUGGEST THAT TES ARE POTENTIALLY INVOLVED IN MYELOID LEUKEMOGENESIS AND HIGHLIGHT THESE SEQUENCES AS POTENTIAL CANDIDATES HARBORING AML-ASSOCIATED VARIATION. 2020 11 3822 22 INVESTIGATING EPIGENETIC EFFECTS OF ACTIVATION-INDUCED DEAMINASE IN CHRONIC LYMPHOCYTIC LEUKEMIA. ACTIVATION INDUCED DEAMINASE (AID) HAS TWO DISTINCT AND WELL DEFINED ROLES, BOTH RELYING ON ITS DEOXYCYTIDINE (DC) DEAMINATING FUNCTION: ONE AS A DNA MUTATOR AND ANOTHER IN DNA DEMETHYLATION. IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), AID WAS PREVIOUSLY SHOWN TO BE AN INDEPENDENT NEGATIVE PROGNOSTIC FACTOR. WHILE THERE IS SUBSTANTIAL IMPACT ON DNA MUTATIONS, EFFECTS OF AID ON GENE EXPRESSION BY PROMOTER DEMETHYLATION OF DISEASE RELATED TARGET GENES IN LEUKEMIA HAS NOT BEEN ADDRESSED. TO SHED LIGHT ON THIS QUESTION, WE AIMED AT DETERMINING GENOME WIDE METHYLATION CHANGES AS WELL AS GENE EXPRESSION CHANGES IN RESPONSE TO AID EXPRESSION IN CLL. ALTHOUGH WE FOUND MINOR DIFFERENCES IN INDIVIDUAL METHYLATION VARIABLE POSITIONS FOLLOWING AID EXPRESSION, WE COULD NOT FIND RECURRENT METHYLATION CHANGES OF SPECIFIC TARGET SITES OR CHANGES IN GLOBAL METHYLATION. 2018 12 4728 24 NOTCH SIGNALING PROMOTES DISEASE INITIATION AND PROGRESSION IN MURINE CHRONIC LYMPHOCYTIC LEUKEMIA. NOTCH1 GAIN-OF-FUNCTION MUTATIONS ARE RECURRENT IN B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL), WHERE THEY ARE ASSOCIATED WITH ACCELERATED DISEASE PROGRESSION AND REFRACTORINESS TO CHEMOTHERAPY. THE SPECIFIC ROLE OF NOTCH1 IN THE DEVELOPMENT AND PROGRESSION OF THIS MALIGNANCY IS UNCLEAR. HERE, WE ASSESS THE IMPACT OF LOSS OF NOTCH SIGNALING AND PATHWAY HYPERACTIVATION IN AN IN VIVO MOUSE MODEL OF CLL (IGH.TEMU) THAT FAITHFULLY REPLICATES MANY FEATURES OF THE HUMAN PATHOLOGY. ABLATION OF CANONICAL NOTCH SIGNALING USING CONDITIONAL GENE INACTIVATION OF RBP-J IN IMMATURE HEMATOPOIETIC OR B-CELL PROGENITORS DELAYED CLL INDUCTION AND REDUCED INCIDENCE OF MICE DEVELOPING DISEASE. IN CONTRAST, FORCED EXPRESSION OF A DOMINANT ACTIVE FORM OF NOTCH RESULTED IN MORE ANIMALS DEVELOPING CLL WITH EARLY DISEASE ONSET. COMPARATIVE ANALYSIS OF GENE EXPRESSION AND EPIGENETIC FEATURES OF NOTCH GAIN-OF-FUNCTION AND CONTROL CLL CELLS REVEALED DIRECT AND INDIRECT REGULATION OF CELL CYCLE-ASSOCIATED GENES, WHICH LED TO INCREASED PROLIFERATION OF NOTCH GAIN-OF-FUNCTION CLL CELLS IN VIVO. THESE RESULTS DEMONSTRATE THAT NOTCH SIGNALING FACILITATES DISEASE INITIATION AND PROMOTES CLL CELL PROLIFERATION AND DISEASE PROGRESSION. 2021 13 160 24 ABERRANT PROMOTER HYPOMETHYLATION IN CLL: DOES IT MATTER FOR DISEASE DEVELOPMENT? OVER THE LAST 30 YEARS, STUDIES OF ABERRANT DNA METHYLATION IN HEMATOLOGIC MALIGNANCIES HAVE BEEN DOMINATED BY THE PRIMARY FOCUS OF UNDERSTANDING PROMOTER HYPERMETHYLATION. THESE EFFORTS NOT ONLY RESULTED IN A BETTER UNDERSTANDING OF THE BASIS OF EPIGENETIC SILENCING OF TUMOR SUPPRESSOR GENES BUT ALSO RESULTED IN APPROVAL OF HYPOMETHYLATING AGENTS FOR THE TREATMENT OF SEVERAL MALIGNANCIES, SUCH AS MYELODYSPLASTIC SYNDROME AND ACUTE MYELOID LEUKEMIA. RECENT ADVANCES IN GLOBAL METHYLATION PROFILING COUPLED WITH THE USE OF MOUSE MODELS SUGGEST THAT ABERRANT PROMOTER HYPOMETHYLATION IS ALSO A FREQUENT EVENT IN HEMATOLOGIC MALIGNANCIES, PARTICULARLY IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). PROMOTER HYPOMETHYLATION AFFECTS GENE EXPRESSION AND, THEREFORE, MAY PLAY AN IMPORTANT ROLE IN DISEASE PATHOGENESIS. HERE, WE REVIEW RECENT FINDINGS AND DISCUSS THE POTENTIAL INVOLVEMENT OF ABERRANT PROMOTER HYPOMETHYLATION IN CLL. 2016 14 1669 29 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 15 18 25 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 16 2765 30 EXPRESSION, EPIGENETIC REGULATION, AND HUMORAL IMMUNOGENICITY OF CANCER-TESTIS ANTIGENS IN CHRONIC MYELOID LEUKEMIA. OBJECTIVE: CANCER-TESTIS (CT) ANTIGENS REPRESENT ATTRACTIVE TARGETS FOR TUMOR IMMUNOTHERAPY BASED ON THEIR TUMOR-RESTRICTED EXPRESSION AND IMMUNOGENICITY. HOWEVER, A BROAD PICTURE OF THE EXPRESSION OF CT ANTIGENS AND ASSOCIATED HUMORAL IMMUNE RESPONSES IN CHRONIC MYELOID LEUKEMIA (CML) IS STILL MISSING. METHODS: WE SCREENED CML CELL LINES AND BONE MARROW (BM) SAMPLES FROM HEALTHY DONORS BY RT-PCR FOR THE EXPRESSION OF 31 CT ANTIGENS BEFORE AND AFTER TREATMENT WITH EPIGENETIC AGENTS. EXPRESSION OF TUMOR-RESTRICTED ANTIGENS WAS FURTHER EXAMINED IN 60 CML PATIENTS AND HUMORAL IMMUNE RESPONSES AGAINST 15 CT ANTIGENS WERE SCREENED BY ELISA. RESULTS: IN UNTREATED CELL LINES WE DETECTED THE EXPRESSION OF 17 CT ANTIGENS THAT WERE ABSENT FROM NORMAL BM. EXPRESSION OF MOST ANTIGENS INCREASED FOLLOWING DEMETHYLATING TREATMENT WITH 5'-AZA-2'-DEOXYCYTIDINE. IN THESE SAMPLES, ONLY PRAME WAS REPEATEDLY DETECTED AND EXPRESSION CORRELATED WITH SEVERAL CLINICOPATHOLOGICAL PARAMETERS AND DECREASED OVERALL SURVIVAL. WE FURTHER SHOW THAT A LOWER FREQUENCY OF PRAME-POSITIVE SAMPLES DURING IMATINIB TREATMENT WAS NOT CAUSED BY GENE-SPECIFIC DOWNREGULATION. ANALYZING THE PATIENTS' ANTIBODY RESPONSES WE FOUND THAT THE VAST MAJORITY OF PATIENTS LACKED SPONTANEOUS IMMUNITY AGAINST CT ANTIGENS INCLUDING PRAME. CONCLUSIONS: CT ANTIGEN EXPRESSION CAN BE INCREASED BY THE APPLICATION OF EPIGENETIC AGENTS AND THE EXPRESSION OF PRAME CORRELATES WITH CLINICOPATHOLOGICAL PARAMETERS AND OVERALL SURVIVAL IN PATIENTS WITH CML, BUT DOES NOT LEAD TO HUMORAL IMMUNE RESPONSES. PRAME-SPECIFIC IMMUNOTHERAPY MIGHT REPRESENT A PROMISING APPROACH FOR THE ERADICATION OF RESIDUAL THERAPY-RESISTANT LEUKEMIC CELLS DUE TO ITS FREQUENT EXPRESSION AND STABILITY UNDER IMATINIB TREATMENT. 2010 17 5477 31 RESTORING THE FUNCTIONAL IMMUNOGENICITY OF CHRONIC LYMPHOCYTIC LEUKEMIA USING EPIGENETIC MODIFIERS. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A MALIGNANCY ARISING FROM IMMUNE CELLS (B-LYMPHOCYTES) ENDOWED WITH INTRINSIC ANTIGEN-PRESENTING CAPABILITIES. SUCH A FUNCTION HOWEVER IS LOST DURING MALIGNANT TRANSFORMATION AND CLL CELLS ARE WELL KNOWN FOR THEIR INABILITY TO PROCESS AND PRESENT ANTIGENS TO THE T-CELL ARM OF THE IMMUNE SYSTEM. INSTEAD, MALIGNANT CLL CELLS ELICIT A VAST ARRAY OF IMMUNE REGULATORY MECHANISMS CONDUCIVE TO T-CELL DYSFUNCTION AND IMMUNOSUPPRESSION. PREVIOUSLY, WE HAVE SHOWN THAT TREATMENT OF CLL CELLS WITH THE DEMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE UNLEASHED TARGET ANTIGEN EXPRESSION. HERE WE SHOW FOR THE FIRST TIME THAT COMBINING TWO EPIGENETIC MODIFIERS, 5-AZA-2'-DEOXYCYTIDINE AND THE HISTONE DEACETYLASE INHIBITOR LAQ824 EFFECTIVELY RESTORES THE IMMUNOGENICITY OF CLL CELL LINES AS WELL AS PRIMARY CELLS OBTAINED FROM CLL PATIENTS. INDEED, SUCH A COMBINATION INDUCES THE EXPRESSION OF NOVEL AND HIGHLY ANTIGENIC CANCER-TESTIS ANTIGENS (CTAS) AND COSTIMULATORY MOLECULES. THESE CHANGES FACILITATE THE FORMATION OF ROBUST SUPRAMOLECULAR ACTIVATION COMPLEXES (SMAC) BETWEEN CLL CELLS AND RESPONDER T-CELLS LEADING TO INTRACELLULAR SIGNALING, LYTIC GRANULE MOBILIZATION, AND POLARIZATION OF FUNCTIONAL AND RELEVANT T-CELL RESPONSES. THIS CASCADE OF T-CELL ACTIVATING EVENTS TRIGGERED BY CLL CELLS WITH RESTORED APC FUNCTION, POINTS TO COMBINED EPIGENETIC MODIFIER TREATMENT AS A POTENTIAL IMMUNOTHERAPEUTIC STRATEGY FOR CLL PATIENTS. 2011 18 5669 20 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 19 1968 21 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 20 1733 27 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