1 2481 162 EPIGENETIC UPREGULATION OF LNCRNAS AT 13Q14.3 IN LEUKEMIA IS LINKED TO THE IN CIS DOWNREGULATION OF A GENE CLUSTER THAT TARGETS NF-KB. NON-CODING RNAS ARE MUCH MORE COMMON THAN PREVIOUSLY THOUGHT. HOWEVER, FOR THE VAST MAJORITY OF NON-CODING RNAS, THE CELLULAR FUNCTION REMAINS ENIGMATIC. THE TWO LONG NON-CODING RNA (LNCRNA) GENES DLEU1 AND DLEU2 MAP TO A CRITICAL REGION AT CHROMOSOMAL BAND 13Q14.3 THAT IS RECURRENTLY DELETED IN SOLID TUMORS AND HEMATOPOIETIC MALIGNANCIES LIKE CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). WHILE NO POINT MUTATIONS HAVE BEEN FOUND IN THE PROTEIN CODING CANDIDATE GENES AT 13Q14.3, THEY ARE DEREGULATED IN MALIGNANT CELLS, SUGGESTING AN EPIGENETIC TUMOR SUPPRESSOR MECHANISM. WE THEREFORE CHARACTERIZED THE EPIGENETIC MAKEUP OF 13Q14.3 IN CLL CELLS AND FOUND HISTONE MODIFICATIONS BY CHROMATIN-IMMUNOPRECIPITATION (CHIP) THAT ARE ASSOCIATED WITH ACTIVATED TRANSCRIPTION AND SIGNIFICANT DNA-DEMETHYLATION AT THE TRANSCRIPTIONAL START SITES OF DLEU1 AND DLEU2 USING 5 DIFFERENT SEMI-QUANTITATIVE AND QUANTITATIVE METHODS (APRIMES, BIOCOBRA, MCIP, MASSARRAY, AND BISULFITE SEQUENCING). THESE EPIGENETIC ABERRATIONS WERE CORRELATED WITH TRANSCRIPTIONAL DEREGULATION OF THE NEIGHBORING CANDIDATE TUMOR SUPPRESSOR GENES, SUGGESTING A COREGULATION IN CIS OF THIS GENE CLUSTER. WE FOUND THAT THE 13Q14.3 GENES IN ADDITION TO THEIR PREVIOUSLY KNOWN FUNCTIONS REGULATE NF-KB ACTIVITY, WHICH WE COULD SHOW AFTER OVEREXPRESSION, SIRNA-MEDIATED KNOCKDOWN, AND DOMINANT-NEGATIVE MUTANT GENES BY USING WESTERN BLOTS WITH PREVIOUSLY UNDESCRIBED ANTIBODIES, BY A CUSTOMIZED ELISA AS WELL AS BY REPORTER ASSAYS. IN ADDITION, WE PERFORMED AN UNBIASED SCREEN OF 810 HUMAN MIRNAS AND IDENTIFIED THE MIR-15/16 FAMILY OF GENES AT 13Q14.3 AS THE STRONGEST INDUCERS OF NF-KB ACTIVITY. IN SUMMARY, THE TUMOR SUPPRESSOR MECHANISM AT 13Q14.3 IS A CLUSTER OF GENES CONTROLLED BY TWO LNCRNA GENES THAT ARE REGULATED BY DNA-METHYLATION AND HISTONE MODIFICATIONS AND WHOSE MEMBERS ALL REGULATE NF-KB. THEREFORE, THE TUMOR SUPPRESSOR MECHANISM IN 13Q14.3 UNDERLINES THE ROLE BOTH OF EPIGENETIC ABERRATIONS AND OF LNCRNA GENES IN HUMAN TUMORIGENESIS AND IS AN EXAMPLE OF COLOCALIZATION OF A FUNCTIONALLY RELATED GENE CLUSTER. 2013 2 326 46 ALLELIC SILENCING AT THE TUMOR-SUPPRESSOR LOCUS 13Q14.3 SUGGESTS AN EPIGENETIC TUMOR-SUPPRESSOR MECHANISM. GENOMIC MATERIAL FROM CHROMOSOME BAND 13Q14.3 DISTAL TO THE RETINOBLASTOMA LOCUS IS RECURRENTLY LOST IN A VARIETY OF HUMAN NEOPLASMS, INDICATING AN AS-YET-UNIDENTIFIED TUMOR-SUPPRESSOR MECHANISM. NO PATHOGENIC MUTATIONS HAVE BEEN FOUND IN THE MINIMALLY DELETED REGION UNTIL NOW. HOWEVER, IN B CELL CHRONIC LYMPHOCYTIC LEUKEMIA TUMORS WITH LOSS OF ONE COPY OF THE CRITICAL REGION, RESPECTIVE CANDIDATE TUMOR-SUPPRESSOR GENES ARE DOWN-REGULATED BY A FACTOR >2, WHICH WOULD BE EXPECTED BY A NORMAL GENE-DOSAGE EFFECT. THIS FINDING POINTS TO AN EPIGENETIC PATHOMECHANISM. WE FIND THAT THE TWO COPIES OF THE CRITICAL REGION REPLICATE ASYNCHRONOUSLY, SUGGESTING DIFFERENTIAL CHROMATIN PACKAGING OF THE TWO COPIES OF 13Q14.3. ALTHOUGH WE ALSO DETECT MONOALLELIC SILENCING OF GENES LOCALIZED IN THE CRITICAL REGION, MONOALLELIC EXPRESSION ORIGINATES FROM EITHER THE MATERNAL OR PATERNAL COPY, EXCLUDING AN IMPRINTING MECHANISM. DNA METHYLATION ANALYSES REVEALED ONE CPG ISLAND OF THE REGION TO BE METHYLATED. DNA DEMETHYLATION OF THIS CPG ISLAND AND GLOBAL HISTONE HYPERACETYLATION INDUCED BIALLELIC EXPRESSION, WHEREAS REPLICATION TIMING WAS NOT AFFECTED. WE PROPOSE THAT DIFFERENTIAL REPLICATION TIMING REPRESENTS AN EARLY EPIGENETIC MARK THAT DISTINGUISHES THE TWO COPIES OF 13Q14.3, RESULTING IN DIFFERENTIAL CHROMATIN PACKAGING AND MONOALLELIC EXPRESSION. ACCORDINGLY, DELETION OF THE SINGLE ACTIVE COPY OF 13Q14.3 RESULTS IN SIGNIFICANT DOWN-REGULATION OF THE CANDIDATE GENES AND LOSS OF FUNCTION, PROVIDING A MODEL FOR THE INTERACTION OF GENETIC LESIONS AND EPIGENETIC SILENCING AT 13Q14.3 IN B CELL CHRONIC LYMPHOCYTIC LEUKEMIA. 2006 3 939 53 CHRONIC LYMPHOCYTIC LEUKEMIA AND 13Q14: MIRS AND MORE. LOSS OF A CRITICAL REGION IN 13Q14.3 [DEL(13Q)] IS THE MOST COMMON GENOMIC ABERRATION IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), OCCURRING IN MORE THAN 50% OF PATIENTS (STILGENBAUER ET AL., ONCOGENE 1998;16:1891 - 1897, DOHNER ET AL., N ENGL J MED 2000;343:1910 - 1916). DESPITE EXTENSIVE INVESTIGATIONS, NO POINT MUTATIONS HAVE BEEN FOUND IN THE REMAINING ALLELE THAT WOULD INACTIVATE ONE OF THE CANDIDATE TUMOR SUPPRESSOR GENES AND EXPLAIN THE PATHOMECHANISM POSTULATED FOR THIS REGION. HOWEVER, THE GENES IN THE REGION ARE SIGNIFICANTLY DOWN-REGULATED IN CLL CELLS, MORE THAN WOULD BE EXPECTED BY GENE DOSAGE, AND RECENTLY A COMPLEX EPIGENETIC REGULATORY MECHANISM WAS IDENTIFIED FOR 13Q14.3 IN NON-MALIGNANT CELLS THAT INVOLVES ASYNCHRONOUS REPLICATION TIMING AND MONOALLELIC EXPRESSION OF CANDIDATE TUMOR SUPPRESSOR GENES. HERE, WE PROPOSE A MODEL OF A MULTIGENIC PATHOMECHANISM IN 13Q14.3, WHERE SEVERAL TUMOR SUPPRESSOR GENES, INCLUDING THE MIRNA GENES MIR-16-1 AND MIR-15A, ARE CO-REGULATED BY THE TWO LONG NON-CODING RNA GENES DLEU1 AND DLEU2 THAT SPAN THE CRITICAL REGION. FURTHERMORE, WE PROPOSE THESE CO-REGULATED GENES TO BE INVOLVED IN THE SAME MOLECULAR PATHWAYS, THEREBY ALSO FORMING A FUNCTIONAL GENE CLUSTER. ELUCIDATING THE MOLECULAR AND CELLULAR FUNCTION OF THE 13Q14.3 CANDIDATE GENES WILL SHED LIGHT ON THE UNDERLYING PATHOMECHANISM OF CLL. 2009 4 1568 31 DNA METHYLATION OF TUMOR-SUPPRESSOR MIRNA GENES IN CHRONIC LYMPHOCYTIC LEUKEMIA. DNA METHYLATION IS ONE OF THE MOST IMPORTANT EPIGENETIC MODIFICATIONS OF THE GENOME INVOLVED IN THE REGULATION OF NUMEROUS CELLULAR PROCESSES THROUGH GENE SILENCING WITHOUT ALTERING DNA SEQUENCES. MIRNAS, A CLASS OF SINGLE-STRANDED NONCODING RNAS OF 19-25 NUCLEOTIDES IN LENGTH, FUNCTION AS POST-TRANSCRIPTIONAL REGULATORS OF GENE EXPRESSION LEADING TO MRNA CLEAVAGE OR TRANSLATIONAL REPRESSION OF THEIR CORRESPONDING TARGET PROTEIN-CODING GENES. RECENTLY, DYSREGULATION OF TUMOR SUPPRESSOR MIRNAS MEDIATED BY PROMOTER DNA HYPERMETHYLATION IS IMPLICATED IN HUMAN CANCERS, INCLUDING B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). MOREOVER, IT APPEARS THAT METHYLATED MIRNA GENES COULD BE POTENTIAL BIOMARKERS FOR CLL DIAGNOSIS OR THERAPY. THIS REVIEW WILL HIGHLIGHT THE ROLE OF ABERRANT METHYLATION OF MIRNA GENES IN THE PATHOGENESIS OF CLL. 2015 5 2747 43 EXPRESSION ANALYSIS OF THE EPIGENETIC METHYLTRANSFERASES AND METHYL-CPG BINDING PROTEIN FAMILIES IN THE NORMAL B-CELL AND B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). THE IMPORTANCE OF EPIGENETIC MODIFICATIONS IN CARCINOGENESIS HAS BEEN A SOURCE OF CONTROVERSY FOR SOME TIME. THERE IS LITTLE DOUBT THAT CHANGES IN GENOMIC HYPERMETHYLATION CONTRIBUTE TO THE SILENCING OF TUMOR SUPPRESSOR GENES. FURTHERMORE, RECENT STUDIES HAVE ALSO IDENTIFIED THE SIGNIFICANCE OF GENOMIC HYPOMETHYLATION ASSOCIATED WITH CHROMOSOMAL INSTABILITY AND TUMORIGENESIS. ONE OF THE MOST PERPLEXING QUESTIONS REGARDING EPIGENETIC MODIFICATIONS AND LEUKEMOGENESIS IS THE RELATIONSHIP WITH DNA METHYLTRANSFERASES (DNMT'S). THE PRIMARY FUNCTION OF THE DNMT ENZYMES IS TO METHYLATE GENOMIC DNA, WHEREAS THE METHYL-CPG BINDING DOMAIN PROTEINS (MBD) INTERPRET THIS METHYLATION SIGNAL AND REGULATE GENE EXPRESSION AND CHROMATIN BEHAVIOR. IN THIS STUDY WE ANALYSE THESE GENE FAMILIES BY QUANTITATIVE REAL-TIME PCR TO INVESTIGATE WHETHER EXPRESSION LEVELS AND THE B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL) PHENOTYPE ARE ASSOCIATED. FURTHERMORE, GIVEN THE EPIGENETIC CROSSTALK BETWEEN GENOME STABILITY AND THE HISTONE CHROMATIN CODE WE HAVE ANALYSED EUKARYOTIC HISTONE METHYLTRANSFERASE (EU-HMTASEI). SURPRISINGLY, WE DID NOT OBSERVE SIGNIFICANT CHANGES IN DNMT1 EXPRESSION IN B-CLL CASES WHEN COMPARED TO NORMAL LYMPHOCYTES, REGARDLESS OF WHETHER WE NORMALISE AGAINST GAPDH OR PCNA AS REFERENCE STANDARDS. INDEED, EXPRESSION OF THE MAINTENANCE AND DE NOVO METHYLASES WERE INDEPENDENTLY REGULATED. OF PARTICULAR NOTE WAS THE SIGNIFICANT DOWN REGULATION OF DNMT3B. FURTHERMORE, WE OBSERVED A POSITIVE CORRELATION BETWEEN HMTASEI EXPRESSION LEVELS AND STAGE OF LEUKEMIA SUGGESTING THAT CHANGES IN THE METHYLATION PATTERNS IN B-CLL MAY REPRESENT DEREGULATION OF THE EPIGENETIC REPERTOIRE THAT ALSO INCLUDE THE METHYLATION DEPENDENT BINDING PROTEINS, MBD2 AND MECP2. WE ENVISAGE CHANGES IN THE EPIGENETIC PROGRAM ARE MULTIFACTORIAL IN NATURE AND POSTULATE THAT THE PREVALENT GENOMIC METHYLASES JUST ONE COMPONENT OF A LARGER EPIGENETIC REPERTOIRE. 2004 6 2771 39 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 7 1484 40 DLEU2: A MEANINGFUL LONG NONCODING RNA IN ONCOGENESIS. BACKGROUND: LONG NON-CODING RNA (LNCRNA) WITH LITTLE OR NO CODING ABILITY HAS SHOWN A VARIETY OF BIOLOGICAL FUNCTIONS IN CANCER, INCLUDING EPIGENETIC REGULATION, DNA DAMAGE, REGULATION OF MICRORNAS, AND PARTICIPATION IN SIGNAL TRANSDUCTION PATHWAYS. LNCRNA CAN BE USED AS AN ONCOGENE AND TUMOR SUPPRESSOR GENE THROUGH TRANSCRIPTIONAL REGULATION IN CANCER. FOR EXAMPLE, THE OVER-EXPRESSED LNCRNA DLEU2 PROMOTES THE OCCURRENCE OF LARYNGEAL CANCER, LUNG CANCER, HEPATOCELLULAR CARCINOMA, ETC., AND INHIBITS THE PROGRESSION OF CHRONIC LYMPHOCYTIC LEUKEMIA. DELETED IN LYMPHOCYTIC LEUKEMIA 2 (DLEU2), AS ONE OF THE LONG NON-CODING RNAS, WAS FIRST FOUND IN CHRONIC LYMPHOBLASTIC LEUKEMIA AND DRAWN INTO THE PROGRESS OF INNUMERABLE CANCERS. THE MOLECULAR MECHANISM OF DLEU2 IN MULTIPLE TUMORS WILL BE REVEALED. METHODS: IN THIS REVIEW, CURRENT STUDIES ON THE BIOLOGICAL FUNCTIONS AND MECHANISMS OF DLEU2 IN TUMORS ARE SUMMARIZED AND ANALYZED; RELATED RESEARCHES ARE SYSTEMATICALLY RETRIEVED AND COLLECTED THROUGH PUBMED. RESULTS: DLEU2, A NOVEL CANCER-RELATED LNCRNA, HAS BEEN DEMONSTRATED TO BE ABNORMALLY EXPRESSED IN VARIOUS MALIGNANT TUMORS, INCLUDING LEUKEMIA, ESOPHAGEAL CANCER, LUNG CANCER, GLIOMA, HEPATOCELLULAR CARCINOMA, MALIGNANT PLEURAL MESOTHELIOMA, BLADDER CANCER, PANCREATIC CANCER, PHARYNX AND THROAT CANCER, RENAL CLEAR CELL CARCINOMA, BREAST CANCER, OSTEOSARCOMA. BESIDES, LNCRNA DLEU2 HAS BEEN SHOWN TO BE INVOLVED IN THE PROCESS OF PROLIFERATION, MIGRATION, INVASION AND INHIBITION OF APOPTOSIS OF CANCER CELLS. CONCLUSION: DUE TO THE BIOLOGICAL FUNCTIONS AND MECHANISMS INVOLVED IN DLEU2, IT MAY REPRESENT AN AVAILABLE BIOMARKER OR POTENTIAL THERAPEUTIC TARGET IN A VARIETY OF MALIGNANT TUMORS. 2021 8 3918 38 LINKING ABERRANT CHROMATIN FEATURES IN CHRONIC LYMPHOCYTIC LEUKEMIA TO TRANSCRIPTION FACTOR NETWORKS. IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), A DIVERSE SET OF GENETIC MUTATIONS IS EMBEDDED IN A DEREGULATED EPIGENETIC LANDSCAPE THAT DRIVES CANCEROGENESIS. TO ELUCIDATE THE ROLE OF ABERRANT CHROMATIN FEATURES, WE MAPPED DNA METHYLATION, SEVEN HISTONE MODIFICATIONS, NUCLEOSOME POSITIONS, CHROMATIN ACCESSIBILITY, BINDING OF EBF1 AND CTCF, AS WELL AS THE TRANSCRIPTOME OF B CELLS FROM CLL PATIENTS AND HEALTHY DONORS. A GLOBALLY INCREASED HISTONE DEACETYLASE ACTIVITY WAS DETECTED AND HALF OF THE GENOME COMPRISED TRANSCRIPTIONALLY DOWNREGULATED PARTIALLY DNA METHYLATED DOMAINS DEMARCATED BY CTCF CLL SAMPLES DISPLAYED A H3K4ME3 REDISTRIBUTION AND NUCLEOSOME GAIN AT PROMOTERS AS WELL AS CHANGES OF ENHANCER ACTIVITY AND ENHANCER LINKAGE TO TARGET GENES. A DNA BINDING MOTIF ANALYSIS IDENTIFIED TRANSCRIPTION FACTORS THAT GAINED OR LOST BINDING IN CLL AT SITES WITH ABERRANT CHROMATIN FEATURES. THESE FINDINGS WERE INTEGRATED INTO A GENE REGULATORY ENHANCER CONTAINING NETWORK ENRICHED FOR B-CELL RECEPTOR SIGNALING PATHWAY COMPONENTS. OUR STUDY PREDICTS NOVEL MOLECULAR LINKS TO TARGETS OF CLL THERAPIES AND PROVIDES A VALUABLE RESOURCE FOR FURTHER STUDIES ON THE EPIGENETIC CONTRIBUTION TO THE DISEASE. 2019 9 1336 36 DESCRIBING A TRANSCRIPTION FACTOR DEPENDENT REGULATION OF THE MICRORNA TRANSCRIPTOME. WHILE THE TRANSCRIPTION REGULATION OF PROTEIN CODING GENES WAS EXTENSIVELY STUDIED, LITTLE IS KNOWN ON HOW TRANSCRIPTION FACTORS ARE INVOLVED IN TRANSCRIPTION OF NON-CODING RNAS, SPECIFICALLY OF MICRORNAS. HERE, WE PROPOSE A STRATEGY TO STUDY THE POTENTIAL ROLE OF TRANSCRIPTION FACTOR IN REGULATING TRANSCRIPTION OF MICRORNAS USING PUBLICALLY AVAILABLE DATA, COMPUTATIONAL RESOURCES AND HIGH THROUGHPUT DATA. WE USE THE H3K4ME3 EPIGENETIC SIGNATURE TO IDENTIFY MICRORNA PROMOTERS AND CHROMATIN IMMUNOPRECIPITATION (CHIP)-SEQUENCING DATA FROM THE ENCODE PROJECT TO IDENTIFY MICRORNA PROMOTERS THAT ARE ENRICHED WITH TRANSCRIPTION FACTOR BINDING SITES. BY TRANSFECTING CELLS OF INTEREST WITH SHRNA TARGETING A TRANSCRIPTION FACTOR OF INTEREST AND SUBJECTING THE CELLS TO MICRORNA ARRAY, WE STUDY THE EFFECT OF THIS TRANSCRIPTION FACTOR ON THE MICRORNA TRANSCRIPTOME. AS AN ILLUSTRATIVE EXAMPLE WE USE OUR STUDY ON THE EFFECT OF STAT3 ON THE MICRORNA TRANSCRIPTOME OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) CELLS. 2016 10 3415 46 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 11 2380 34 EPIGENETIC REGULATION OF WNT SIGNALING IN CHRONIC LYMPHOCYTIC LEUKEMIA. CERTAIN WNT AND WNT NETWORK TARGET GENES ARE EXPRESSED AT HIGHER OR LOWER LEVELS IN CHRONIC LYMPHOCYTIC LEUKEMIA COMPARED WITH NORMAL B-CELLS. THIS INCLUDES UPREGULATION OF NUCLEAR COMPLEX GENES, AS WELL AS GENES FOR CYTOPLASMIC PROTEINS AND WNT LIGANDS AND THEIR COGNATE RECEPTORS. IN ADDITION, EPIGENETIC SILENCING OF SEVERAL NEGATIVE REGULATORS OF THE WNT PATHWAY HAVE BEEN IDENTIFIED. THE BALANCE BETWEEN EPIGENETIC DOWNREGULATION OF NEGATIVE EFFECTOR GENES AND INCREASED EXPRESSION OF POSITIVE EFFECTOR GENES DEMONSTRATE THAT THE EPIGENETIC DOWNREGULATION OF WNT ANTAGONISTS IS ONE MECHANISM, PERHAPS THE MAIN MECHANISM, THAT IS PERMISSIVE TO ACTIVE WNT SIGNALING IN CHRONIC LYMPHOCYTIC LEUKEMIA. MOREOVER, CONSTITUTIVE ACTIVATION OF THE WNT NETWORK AND TARGET GENES IS LIKELY TO IMPACT ON ADDITIONAL INTERACTING SIGNALING PATHWAYS. BASED ON PUBLISHED STUDIES, WE PROPOSE A MODEL OF WNT SIGNALING THAT INVOLVES MAINLY PERMISSIVE EXPRESSION, AND SOMETIMES OVEREXPRESSION, OF POSITIVE EFFECTORS AND DOWNREGULATION OF NEGATIVE REGULATORS IN THE NETWORK. IN THIS MODEL, DNA METHYLATION, HISTONE MODIFICATIONS AND ALTERED EXPRESSION OF MICRORNA MOLECULES INTERACT TO ALLOW CONTINUOUS WNT SIGNALING. 2010 12 1976 33 EPIGENETIC ALTERATIONS IN A MURINE MODEL FOR CHRONIC LYMPHOCYTIC LEUKEMIA. EARLY STAGES IN THE DEVELOPMENT OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) HAVE NOT BEEN EXPLORED MAINLY DUE TO THE INABILITY TO STUDY NORMAL B-CELLS EN ROUTE TO TRANSFORMATION. IN ORDER TO DETERMINE SUCH EARLY EVENTS OF LEUKEMOGENESIS, WE HAVE USED A WELL ESTABLISHED MOUSE MODEL FOR CLL. OVER-EXPRESSION OF HUMAN TCL1, A KNOWN CLL ONCOGENE IN MURINE B-CELLS LEADS TO THE DEVELOPMENT OF MATURE CD19+/CD5+/IGM+ CLONAL LEUKEMIA WITH A DISEASE PHENOTYPE SIMILAR TO THAT SEEN IN HUMAN CLL. HEREIN, WE REVIEW OUR RECENT STUDY USING THIS TCL1-DRIVEN MOUSE MODEL FOR CLL AND CORRESPONDING HUMAN CLL SAMPLES IN A CROSS-SPECIES EPIGENOMICS APPROACH TO ADDRESS THE TIMING AND RELEVANCE OF EPIGENETIC EVENTS OCCURRING DURING LEUKEMOGENESIS. WE DEMONSTRATED THAT THE MOUSE MODEL RECAPITULATES THE EPIGENETIC EVENTS THAT HAVE BEEN REPORTED FOR HUMAN CLL, AFFIRMING THE POWER AND VALIDITY OF THIS MOUSE MODEL TO STUDY EARLY EPIGENETIC EVENTS IN CANCER PROGRESSION. EPIGENETIC ALTERATIONS ARE DETECTED AS EARLY AS THREE MONTHS AFTER BIRTH, FAR BEFORE DISEASE MANIFESTS AT ABOUT 11 MONTHS OF AGE. THESE MICE UNDERGO NFKAPPAB REPRESSOR COMPLEX MEDIATED INACTIVATION OF THE TRANSCRIPTION FACTOR FOXD3, WHOSE TARGETS BECOME ABERRANTLY METHYLATED AND SILENCED IN MOUSE AND HUMAN CLL. OVERALL, OUR DATA SUGGEST THE ACCUMULATED EPIGENETIC ALTERATIONS DURING CLL PATHOGENESIS AS A CONSEQUENCE OF GENE SILENCING THROUGH TCL1 AND NFKAPPAB REPRESSOR COMPLEX, SUGGESTING THE RELEVANCE FOR NFKAPPAB AS A THERAPEUTIC TARGET IN CLL. 2009 13 1659 47 DOWN-REGULATION OF CANDIDATE TUMOR SUPPRESSOR GENES WITHIN CHROMOSOME BAND 13Q14.3 IS INDEPENDENT OF THE DNA METHYLATION PATTERN IN B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA. LOSS OF GENOMIC MATERIAL FROM CHROMOSOMAL BAND 13Q14.3 IS THE MOST COMMON GENETIC IMBALANCE IN B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL) AND MANTLE CELL LYMPHOMA, POINTING TO THE INVOLVEMENT OF THIS REGION IN A TUMOR SUPPRESSOR MECHANISM. FROM THE MINIMALLY DELETED REGION, 3 CANDIDATE GENES HAVE BEEN ISOLATED, RFP2, BCMS, AND BCMSUN. DNA SEQUENCE ANALYSES HAVE FAILED TO DETECT SMALL MUTATIONS IN ANY OF THESE GENES, SUGGESTING A DIFFERENT PATHOMECHANISM, MOST LIKELY HAPLOINSUFFICIENCY. WE, THEREFORE, TESTED B-CLL PATIENTS FOR EPIGENETIC ABERRATIONS BY MEASURING EXPRESSION OF GENES FROM 13Q14.3 AND METHYLATION OF THEIR PROMOTOR REGION. RB1, CLLD7, KPNA3, CLLD6, AND RFP2 WERE DOWN-REGULATED IN B-CLL PATIENTS AS COMPARED WITH B CELLS OF HEALTHY DONORS, WITH RFP2 SHOWING THE MOST PRONOUNCED LOSS OF EXPRESSION. TO TEST WHETHER THIS LOSS OF GENE EXPRESSION IS ASSOCIATED WITH METHYLATION OF CPG ISLANDS IN THE RESPECTIVE PROMOTOR REGIONS, WE PERFORMED METHYLATION-SENSITIVE QUANTITATIVE POLYMERASE CHAIN REACTION ANALYSES AND BISULFITE SEQUENCING ON DNA FROM B-CLL PATIENTS. NO DIFFERENCE IN THE METHYLATION PATTERNS COULD BE DETECTED IN ANY CPG ISLAND OF THE MINIMALLY DELETED REGION. DOWN-REGULATION OF GENES WITHIN CHROMOSOMAL BAND 13Q14.3 IN B-CLL IS IN LINE WITH THE CONCEPT OF HAPLOINSUFFICIENCY, BUT THIS TUMOR-SPECIFIC PHENOMENON IS NOT ASSOCIATED WITH DNA METHYLATION. 2002 14 3822 33 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 15 825 39 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 16 160 28 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 17 59 40 A GENOME-WIDE SCREEN IDENTIFIES FREQUENTLY METHYLATED GENES IN HAEMATOLOGICAL AND EPITHELIAL CANCERS. BACKGROUND: GENETIC AS WELL AS EPIGENETIC ALTERATIONS ARE A HALLMARK OF BOTH EPITHELIAL AND HAEMATOLOGICAL MALIGNANCIES. HIGH THROUGHPUT SCREENS ARE REQUIRED TO IDENTIFY EPIGENETIC MARKERS THAT CAN BE USEFUL FOR DIAGNOSTIC AND PROGNOSTIC PURPOSES ACROSS MALIGNANCIES. RESULTS: HERE WE REPORT FOR THE FIRST TIME THE USE OF THE MIRA ASSAY (METHYLATED CPG ISLAND RECOVERY ASSAY) IN COMBINATION WITH GENOME-WIDE CPG ISLAND ARRAYS TO IDENTIFY EPIGENETIC MOLECULAR MARKERS IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA (ALL) ON A GENOME-WIDE SCALE. WE IDENTIFIED 30 GENES DEMONSTRATING METHYLATION FREQUENCIES OF > OR =25% IN CHILDHOOD ALL, NINE GENES SHOWED SIGNIFICANTLY DIFFERENT METHYLATION FREQUENCIES IN B VS T-ALL. FOR MAJORITY OF THE GENES EXPRESSION COULD BE RESTORED IN METHYLATED LEUKEMIA LINES AFTER TREATMENT WITH 5-AZADC. FORTY-FOUR PERCENT OF THE GENES REPRESENT TARGETS OF THE POLYCOMB COMPLEX. IN CHRONIC MYELOID LEUKEMIA (CML) TWO OF THE GENES, (TFAP2A AND EBF2), DEMONSTRATED INCREASED METHYLATION IN BLAST CRISIS COMPARED TO CHRONIC PHASE (P < 0.05). FURTHERMORE HYPERMETHYLATION OF AN AUTOPHAGY RELATED GENE ATG16L2 WAS ASSOCIATED WITH POORER PROGNOSIS IN TERMS OF MOLECULAR RESPONSE TO IMATINIB TREATMENT. LASTLY WE DEMONSTRATED THAT TEN OF THESE GENES WERE ALSO FREQUENTLY METHYLATED IN COMMON EPITHELIAL CANCERS. CONCLUSION: IN SUMMARY WE HAVE IDENTIFIED A LARGE NUMBER OF GENES SHOWING FREQUENT METHYLATION IN CHILDHOOD ALL, METHYLATION STATUS OF TWO OF THESE GENES IS ASSOCIATED WITH ADVANCED DISEASE IN CML AND METHYLATION STATUS OF ANOTHER GENE IS ASSOCIATED WITH PROGNOSIS. IN ADDITION A SUBSET OF THESE GENES MAY ACT AS EPIGENETIC MARKERS ACROSS HEMATOLOGICAL MALIGNANCIES AS WELL AS COMMON EPITHELIAL CANCERS. 2010 18 851 32 CHIP-SEQ ANALYSIS OF HUMAN CHRONIC MYELOID LEUKEMIA CELLS. MANY TRANSCRIPTION FACTORS, CHROMATIN-ASSOCIATED PROTEINS AND REGULATORY DNA ELEMENTS ARE GENETICALLY AND/OR EPIGENETICALLY ALTERED IN CANCER, INCLUDING CHRONIC MYELOID LEUKEMIA (CML). THIS LEADS TO DEREGULATION OF TRANSCRIPTION THAT IS OFTEN CAUSALLY LINKED TO THE TUMORIGENIC STATE. CHROMATIN-IMMUNOPRECIPITATION COUPLED WITH MASSIVELY PARALLEL DNA SEQUENCING (CHIP-SEQ) IS THE KEY TECHNOLOGY TO STUDY TRANSCRIPTION AS IT ALLOWS IN VIVO WHOLE-GENOME MAPPING OF EPIGENETIC MODIFICATIONS AND INTERACTIONS OF PROTEINS WITH DNA OR CHROMATIN. HOWEVER, NUMEROUS DNA/CHROMATIN-BINDING PROTEINS, INCLUDING EZH2, REMAIN DIFFICULT TO "CHIP," THUS YIELDING GENOME-WIDE BINDING MAPS OF ONLY SUBOPTIMAL QUALITY. HERE, WE DESCRIBE A CHIP-SEQ PROTOCOL OPTIMIZED FOR HIGH-QUALITY PROTEIN-GENOME BINDING MAPS THAT HAVE PROVEN ESPECIALLY USEFUL FOR STUDYING DIFFICULT TO 'CHIP' TRANSCRIPTION REGULATORY FACTORS IN CHRONIC MYELOID LEUKEMIA (CML) AND RELATED MALIGNANCIES. 2016 19 206 41 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 20 4004 37 LOSS OF THE POLYCOMB MARK FROM BIVALENT PROMOTERS LEADS TO ACTIVATION OF CANCER-PROMOTING GENES IN COLORECTAL TUMORS. IN COLON TUMORS, THE TRANSCRIPTION OF MANY GENES BECOMES DEREGULATED BY POORLY DEFINED EPIGENETIC MECHANISMS THAT HAVE BEEN STUDIED MAINLY IN ESTABLISHED CELL LINES. IN THIS STUDY, WE USED FROZEN HUMAN COLON TISSUES TO ANALYZE PATTERNS OF HISTONE MODIFICATION AND DNA CYTOSINE METHYLATION IN CANCER AND MATCHED NORMAL MUCOSA SPECIMENS. DNA METHYLATION IS STRONGLY TARGETED TO BIVALENT H3K4ME3- AND H3K27ME3-ASSOCIATED PROMOTERS, WHICH LOSE BOTH HISTONE MARKS AND ACQUIRE DNA METHYLATION. HOWEVER, WE FOUND THAT LOSS OF THE POLYCOMB MARK H3K27ME3 FROM BIVALENT PROMOTERS WAS ACCOMPANIED OFTEN BY ACTIVATION OF GENES ASSOCIATED WITH CANCER PROGRESSION, INCLUDING NUMEROUS STEM CELL REGULATORS, ONCOGENES, AND PROLIFERATION-ASSOCIATED GENES. INDEED, WE FOUND MANY OF THESE SAME GENES WERE ALSO ACTIVATED IN PATIENTS WITH ULCERATIVE COLITIS WHERE CHRONIC INFLAMMATION PREDISPOSES THEM TO COLON CANCER. BASED ON OUR FINDINGS, WE PROPOSE THAT A LOSS OF POLYCOMB REPRESSION AT BIVALENT GENES COMBINED WITH AN ENSUING SELECTION FOR TUMOR-DRIVING EVENTS PLAYS A MAJOR ROLE IN CANCER PROGRESSION. 2014