1 139 122 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 2 3532 39 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 3 5669 31 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 4 4694 40 NEXT-GENERATION SEQUENCING IDENTIFIES MAJOR DNA METHYLATION CHANGES DURING PROGRESSION OF PH+ CHRONIC MYELOID LEUKEMIA. LITTLE IS KNOWN ABOUT THE IMPACT OF DNA METHYLATION ON THE EVOLUTION/PROGRESSION OF PH+ CHRONIC MYELOID LEUKEMIA (CML). WE INVESTIGATED THE METHYLOME OF CML PATIENTS IN CHRONIC PHASE (CP-CML), ACCELERATED PHASE (AP-CML) AND BLAST CRISIS (BC-CML) AS WELL AS IN CONTROLS BY REDUCED REPRESENTATION BISULFITE SEQUENCING. ALTHOUGH ONLY ~600 DIFFERENTIALLY METHYLATED CPG SITES WERE IDENTIFIED IN SAMPLES OBTAINED FROM CP-CML PATIENTS COMPARED WITH CONTROLS, ~6500 DIFFERENTIALLY METHYLATED CPG SITES WERE FOUND IN SAMPLES FROM BC-CML PATIENTS. IN THE MAJORITY OF AFFECTED CPG SITES, METHYLATION WAS INCREASED. IN CP-CML PATIENTS WHO PROGRESSED TO AP-CML/BC-CML, WE IDENTIFIED UP TO 897 GENES THAT WERE METHYLATED AT THE TIME OF PROGRESSION BUT NOT AT THE TIME OF DIAGNOSIS. USING RNA-SEQUENCING, WE OBSERVED DOWNREGULATED EXPRESSION OF MANY OF THESE GENES IN BC-CML COMPARED WITH CP-CML SAMPLES. SEVERAL OF THEM ARE WELL-KNOWN TUMOR-SUPPRESSOR GENES OR REGULATORS OF CELL PROLIFERATION, AND GENE RE-EXPRESSION WAS OBSERVED BY THE USE OF EPIGENETIC ACTIVE DRUGS. TOGETHER, OUR RESULTS DEMONSTRATE THAT CPG SITE METHYLATION CLEARLY INCREASES DURING CML PROGRESSION AND THAT IT MAY PROVIDE A USEFUL BASIS FOR REVEALING NEW TARGETS OF THERAPY IN ADVANCED CML. 2016 5 149 40 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 6 4388 50 MLL2/KMT2D AND MLL3/KMT2C EXPRESSION CORRELATES WITH DISEASE PROGRESSION AND RESPONSE TO IMATINIB MESYLATE IN CHRONIC MYELOID LEUKEMIA. BACKGROUND: CHRONIC MYELOID LEUKEMIA (CML) IS A CLONAL MYELOPROLIFERATIVE NEOPLASM WHOSE PATHOGENESIS IS LINKED TO THE PHILADELPHIA CHROMOSOME PRESENCE THAT GENERATES THE BCR-ABL1 FUSION ONCOGENE. TYROSINE KINASE INHIBITORS (TKI) SUCH AS IMATINIB MESYLATE (IM) DRAMATICALLY IMPROVED THE TREATMENT EFFICIENCY AND SURVIVAL OF CML PATIENTS BY TARGETING BCR-ABL TYROSINE KINASE. THE DISEASE SHOWS THREE DISTINCT CLINICAL-LABORATORY STAGES: CHRONIC PHASE, ACCELERATED PHASE AND BLAST CRISIS. ALTHOUGH PATIENTS IN THE CHRONIC PHASE RESPOND WELL TO TREATMENT, PATIENTS IN THE ACCELERATED PHASE OR BLAST CRISIS USUALLY SHOW THERAPY RESISTANCE AND CML RELAPSE. IT IS CRUCIAL, THEREFORE, TO IDENTIFY BIOMARKERS TO PREDICT CML GENETIC EVOLUTION AND RESISTANCE TO TKI THERAPY, CONSIDERING NOT ONLY THE EFFECTS OF GENETIC ABERRATIONS BUT ALSO THE ROLE OF EPIGENETIC ALTERATIONS DURING THE DISEASE. ALTHOUGH DYSREGULATIONS IN EPIGENETIC MODULATORS SUCH AS HISTONE METHYLTRASNFERASES HAVE ALREADY BEEN DESCRIBED FOR SOME HEMATOLOGIC MALIGNANCIES, TO DATE VERY LIMITED DATA IS AVAILABLE FOR CML, ESPECIALLY WHEN CONSIDERING THE LYSINE METHYLTRANSFERASE MLL2/KMT2D AND MLL3/KMT2C. METHODS: HERE WE INVESTIGATED THE EXPRESSION PROFILE OF BOTH GENES IN CML PATIENTS IN DIFFERENT STAGES OF THE DISEASE, IN PATIENTS SHOWING DIFFERENT RESPONSES TO THERAPY WITH IM AND IN NON-NEOPLASTIC CONTROL SAMPLES. IMATINIB SENSITIVE AND RESISTANT CML CELL LINES WERE ALSO USED TO INVESTIGATE WHETHER TREATMENT WITH OTHER TYROSINE KINASE INHIBITORS INTERFERED IN THEIR EXPRESSION. RESULTS: IN PATIENTS, BOTH METHYLTRANSFERASES WERE EITHER UPREGULATED OR WITH BASAL EXPRESSION LEVEL DURING THE CHRONIC PHASE COMPARED TO CONTROLS. INTERESTINGLY, MLL3/KMT2C AND SPECIALLY MLL2/KMT2D LEVELS DECREASED DURING DISEASE PROGRESSION CORRELATING WITH DISTINCT CLINICAL STAGES. FURTHERMORE, MLL2/KMT2D WAS DECREASED IN PATIENTS RESISTANT TO IM TREATMENT. A RESCUE IN THE EXPRESSION OF BOTH MLL GENES WAS OBSERVED IN KCL22S, A CML CELL LINE SENSITIVE TO IM, AFTER TREATMENT WITH DASATINIB OR NILOTINIB WHICH WAS ASSOCIATED WITH A HIGHER RATE OF APOPTOSIS, AN ENHANCED EXPRESSION OF P21 (CDKN1A) AND A CONCOMITANT DECREASE IN THE EXPRESSION OF CDK2, CDK4 AND CYCLIN B1 (CCNB1) IN COMPARISON TO UNTREATED KCL22S CONTROL OR IM RESISTANT KCL22R CELL LINE, WHICH SUGGESTS INVOLVEMENT OF P53 REGULATED PATHWAY. CONCLUSION: OUR RESULTS ESTABLISHED A NEW ASSOCIATION BETWEEN MLL2/KMT2D AND MLL3/KMT2C GENES WITH CML AND SUGGEST THAT MLL2/KMT2D IS ASSOCIATED WITH DISEASE EVOLUTION AND MAY BE A POTENTIAL MARKER TO PREDICT THE DEVELOPMENT OF THERAPY RESISTANCE. 2018 7 5259 38 PROGRESSIVE DE NOVO DNA METHYLATION AT THE BCR-ABL LOCUS IN THE COURSE OF CHRONIC MYELOGENOUS LEUKEMIA. DE NOVO METHYLATION OF CPG ISLANDS IS A RARE EVENT IN MAMMALIAN CELLS. IT HAS BEEN OBSERVED IN THE COURSE OF DEVELOPMENTAL PROCESSES, SUCH AS X CHROMOSOME INACTIVATION AND GENOMIC IMPRINTING. THE METHYLATION OF DNA, AN IMPORTANT FACTOR IN THE EPIGENETIC CONTROL OF GENE EXPRESSION, MAY ALSO BE INVOLVED IN TUMORIGENESIS. AFTER THE T(9;22) CHROMOSOMAL TRANSLOCATION AND GENERATION OF THE PHILADELPHIA CHROMOSOME, THE INITIATING EVENT IN CHRONIC MYELOGENOUS LEUKEMIA (CML), MOST OF THE ABL CODING SEQUENCE IS FUSED TO THE 5' REGION OF THE BCR GENE. EXPRESSION OF THE HYBRID BCR-ABL GENE IS, THEREFORE, REGULATED BY THE BCR PROMOTER. IN MOST CASES OF CML, ONE OF THE TWO ABL PROMOTERS (PA) IS NESTED WITHIN THE BCR-ABL TRANSCRIPTIONAL UNIT AND SHOULD BE ABLE TO TRANSCRIBE THE TYPE IA 6-KB NORMAL ABL MRNA FROM THE PHILADELPHIA CHROMOSOME. HOWEVER, WE HAVE FOUND THAT THE 6-KB TRANSCRIPT IS PRESENT ONLY IN CML CELL LINES CONTAINING A NORMAL ABL ALLELE AND THAT THE APPARENT INACTIVATION OF THE NESTED PA PROMOTER IS ASSOCIATED WITH ALLELE-SPECIFIC METHYLATION. FURTHERMORE, WE HAVE NOTICED THAT THE PA PROMOTER IS CONTAINED WITHIN A CPG ISLAND AND UNDERGOES PROGRESSIVE DE NOVO METHYLATION IN THE COURSE OF THE DISEASE. THIS IS ATTESTED TO BY THE FACT THAT DNA SAMPLES FROM CML PATIENTS THAT ARE METHYLATION-FREE AT THE TIME OF DIAGNOSIS INVARIABLY BECOME METHYLATED IN ADVANCED CML. SINCE TUMOR PROGRESSION IN CML CANNOT ALWAYS BE INFERRED FROM THE CLINICAL PRESENTATION, ASSESSMENT OF DE NOVO CPG METHYLATION MAY PROVE TO BE OF CRITICAL VALUE IN MANAGEMENT OF THE DISEASE. IT COULD HERALD BLASTIC TRANSFORMATION AT A STAGE WHEN BONE MARROW TRANSPLANTATION, THE ONLY POTENTIALLY CURATIVE THERAPEUTIC PROCEDURE IN CML, IS STILL EFFECTIVE. 1994 8 59 44 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 9 151 30 ABERRANT METHYLATION AND IMPAIRED EXPRESSION OF THE P15(INK4B) CELL CYCLE REGULATORY GENE IN CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML). THE IMPORTANT CELL CYCLE REGULATORY GENE P15(INK4B) HAS BEEN SHOWN TO BE INACTIVATED IN ACUTE MYELOID LEUKEMIA AND MYELODYSPLASTIC SYNDROME. LITTLE IS KNOWN ABOUT THE EXPRESSION AND EPIGENETIC MODIFICATION OF THIS GENE IN CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) THAT BELONGS TO THE MYELODYSPLASTIC/MYELOPROLIFERATIVE DISORDERS (MDS/MPD) WITH A HIGH PROPORTION OF BLASTIC TRANSFORMATION. ANALYSIS OF BONE MARROW TREPHINES IN A SERIES OF 33 CMML CASES SHOWED AN ABERRANT P15(INK4B) GENE METHYLATION IN UP TO 58% OF CASES. METHYLATION WAS ANALYZED EMPLOYING DIFFERENT METHYLATION-SPECIFIC PCR AND GENOMIC SEQUENCING PROTOCOLS. IT TURNED OUT TO BE SPREAD OVER A BROAD AREA OF THE 5' REGION AND EXHIBITED SUBSTANTIAL HETEROGENEITY BETWEEN CASES AND EVEN IN INDIVIDUAL PATIENTS. THE DEGREE OF ABERRANT METHYLATION WAS CORRELATED WITH A REDUCED MRNA AS WELL AS REDUCED PROTEIN EXPRESSION, AND WAS ASSOCIATED WITH A HIGHER EXPRESSION OF DNA METHYLTRANSFERASE DNMT 3A. WE CONCLUDE THAT ABERRANT GENE METHYLATION IS A FREQUENT EVENT IN CMML THAT MIGHT CONTRIBUTE TO THE PATHOGENESIS OF THIS MDS/MPD. 2003 10 1593 41 DNA METHYLATION PROFILING REVEALS A PATHOLOGICAL SIGNATURE THAT CONTRIBUTES TO TRANSCRIPTIONAL DEFECTS OF CD34(+) CD15(-) CELLS IN EARLY CHRONIC-PHASE CHRONIC MYELOID LEUKEMIA. DESPITE THE HIGH EFFICIENCY OF TYROSINE KINASE INHIBITORS (TKI), SOME PATIENTS WITH CHRONIC MYELOID LEUKEMIA (CML) WILL DISPLAY RESIDUAL DISEASE THAT CAN BECOME RESISTANT TO TREATMENT, INDICATING INTRACLONAL HETEROGENEITY IN CHRONIC-PHASE CML (CP-CML). TO DETERMINE THE BASIS OF THIS HETEROGENEITY, WE CONDUCTED THE FIRST EXHAUSTIVE CHARACTERIZATION OF THE DNA METHYLATION PATTERN OF SORTED CP-CML CD34(+) CD15(-) (IMMATURE) AND CD34(-) CD15(+) (MATURE) CELLS AT DIAGNOSIS (PRIOR TO ANY TREATMENT) AND COMPARED IT TO THAT OF CD34(+) CD15(-) AND CD34(-) CD15(+) CELLS ISOLATED FROM HEALTHY DONORS (HD). IN BOTH CELL TYPES, WE IDENTIFIED SEVERAL HUNDREDS OF DIFFERENTIALLY METHYLATED REGIONS (DMRS) SHOWING DNA METHYLATION CHANGES BETWEEN CP-CML AND HD SAMPLES, WITH ONLY A SUBSET OF THEM IN COMMON BETWEEN CD34(+) CD15(-) AND CD34(-) CD15(+) CELLS. THIS SUGGESTED DNA METHYLATION VARIABILITY WITHIN THE SAME CML CLONE. WE ALSO IDENTIFIED 70 GENES THAT COULD BE ABERRANTLY REPRESSED UPON HYPERMETHYLATION AND 171 GENES THAT COULD BE ABERRANTLY EXPRESSED UPON HYPOMETHYLATION OF SOME OF THESE DMRS IN CP-CML CELLS, AMONG WHICH 18 AND 81, RESPECTIVELY, WERE IN CP-CML CD34(+) CD15(-) CELLS ONLY. WE THEN VALIDATED THE DNA METHYLATION AND EXPRESSION DEFECTS OF SELECTED CANDIDATE GENES. SPECIFICALLY, WE IDENTIFIED GAS2, A CANDIDATE ONCOGENE, AS A NEW EXAMPLE OF GENE THE HYPOMETHYLATION OF WHICH IS ASSOCIATED WITH ROBUST OVEREXPRESSION IN CP-CML CELLS. ALTOGETHER, WE DEMONSTRATED THAT DNA METHYLATION ABNORMALITIES EXIST AT EARLY STAGES OF CML AND CAN AFFECT THE TRANSCRIPTIONAL LANDSCAPE OF MALIGNANT CELLS. THESE OBSERVATIONS COULD LEAD TO THE DEVELOPMENT OF COMBINATION TREATMENTS WITH EPIGENETIC DRUGS AND TKI FOR CP-CML. 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 3461 42 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 13 1669 39 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 14 3087 42 GENOME?WIDE EXPRESSION AND METHYLATION ANALYSES REVEAL ABERRANT CELL ADHESION SIGNALING IN TYROSINE KINASE INHIBITOR?RESISTANT CML CELLS. ALTHOUGH CHRONIC MYELOID LEUKEMIA (CML) CAN BE EFFECTIVELY TREATED USING BCR?ABL1 KINASE INHIBITORS, RESISTANCE DUE TO KINASE ALTERATIONS OR TO BCR?ABL1 INDEPENDENT MECHANISMS REMAIN A THERAPEUTIC CHALLENGE. FOR THE LATTER, THE UNDERLYING MECHANISMS ARE WIDELY DISCUSSED; FOR INSTANCE, GENE EXPRESSION CHANGES, EPIGENETIC FACTORS AND ALTERNATIVE SIGNALING PATHWAY ACTIVATION. IN THE PRESENT STUDY, IN VITRO?CML CELL MODELS OF RESISTANCE AGAINST THE TYROSINE KINASE INHIBITORS (TKIS) IMATINIB (0.5 AND 2 MICROM) AND NILOTINIB (0.1 MICROM) WITH BIOLOGICAL REPLICATES WERE GENERATED TO IDENTIFY NOVEL MECHANISMS OF RESISTANCE. SUBSEQUENTLY, GENOME?WIDE MRNA EXPRESSION AND DNA METHYLATION WERE ANALYZED. WHILE MRNA EXPRESSION PATTERNS DIFFERED LARGELY BETWEEN BIOLOGICAL REPLICATES, THERE WAS AN OVERLAP OF 71 GENES DIFFERENTIALLY EXPRESSED BETWEEN CELLS RESISTANT AGAINST IMATINIB OR NILOTINIB. MOREOVER, ALL TKI RESISTANT CELL LINES DEMONSTRATED A SLIGHT HYPERMETHYLATION COMPARED WITH NATIVE CELLS. IN A COMBINED ANALYSIS OF 151 GENES DIFFERENTIALLY EXPRESSED IN THE BIOLOGICAL REPLICATES OF IMATINIB RESISTANCE, CELL ADHESION SIGNALING, IN PARTICULAR THE CELLULAR MATRIX PROTEIN FIBRONECTIN 1 (FN1), WAS SIGNIFICANTLY DYSREGULATED. THIS GENE WAS ALSO DOWNREGULATED IN NILOTINIB RESISTANCE. FURTHER ANALYSES SHOWED SIGNIFICANT FN1?DOWNREGULATION IN IMATINIB RESISTANCE ON MRNA (P<0.001) AND PROTEIN LEVEL (P<0.001). SIRNA?MEDIATED FN1?KNOCKDOWN IN NATIVE CELLS REDUCED CELL ADHESION (P=0.02), DECREASED IMATINIB SUSCEPTIBILITY VISIBLE BY HIGHER KI?67 EXPRESSION (1.5?FOLD, P=0.04) AND INCREASED CELL NUMBER (1.5?FOLD, P=0.03). VICE VERSA, RECOVERY OF FN1?EXPRESSION IN IMATINIB RESISTANT CELLS WAS SUFFICIENT TO PARTIALLY RESTORE THE RESPONSE TO IMATINIB. OVERALL, THESE RESULTS SUGGESTED A ROLE OF CELL ADHESION SIGNALING AND FIBRONECTIN 1 IN TKI RESISTANT CML AND A POTENTIAL TARGET FOR NOVEL STRATEGIES IN TREATMENT OF RESISTANT CML. 2022 15 2465 35 EPIGENETIC THERAPY WITH HYDRALAZINE AND MAGNESIUM VALPROATE REVERSES IMATINIB RESISTANCE IN PATIENTS WITH CHRONIC MYELOID LEUKEMIA. THE EPIGENETIC DRUGS HYDRALAZINE AND VALPROATE WERE ADMINISTERED IN A COMPASSIONATE MANNER TO 8 PATIENTS WITH CHRONIC MYELOID LEUKEMIA (CML) REFRACTORY TO IMATINIB. TWO PATIENTS HAD A COMPLETE HEMATOLOGIC RESPONSE (25%),1 MAJOR CYTOGENETIC RESPONSE, 1 COMPLETE CYTOGENETIC RESPONSE (25% ANY CYTOGENETIC RESPONSE), AND 3 (37.5%)STABLE DISEASE. NO GRADE 3 OR 4 TOXICITY WAS OBSERVED. THESE RESULTS SHOW THE ABILITY OF EPIGENETIC THERAPY TO REVERT IMATINIB RESISTANCE. BACKGROUND: EPIGENETIC ALTERATIONS PARTICIPATE IN THE DEVELOPMENT OF ACQUIRED RESISTANCE TO IMATINIB, HENCE, THE DNA METHYLATION, AND HISTONE DEACETYLASE INHIBITORS HYDRALAZINE AND VALPROATE, RESPECTIVELY, HAS THE POTENTIAL TO OVERCOME IT. PATIENT AND METHODS: A SERIES OF 8 PATIENTS WITH CHRONIC MYELOID LEUKEMIA (CML) REFRACTORY TO IMATINIB MESYLATE WITH NO ACCESS TO SECOND-GENERATION TYROSINE KINASE INHIBITORS WERE TREATED WITH HYDRALAZINE AND VALPROATE IN A COMPASSIONATE MANNER. CLINICAL EFFICACY AND SAFETY OF THESE DRUGS ADDED TO IMATINIB MESYLATE WERE EVALUATED. RESULTS: TWO PATIENTS WERE IN THE BLAST PHASE, 5 WERE IN THE ACCELERATED PHASE, AND 1 WAS IN THE CHRONIC PHASE. ALL THE PATIENTS CONTINUED WITH THE SAME DOSE OF IMATINIB THAT THEY HAD BEEN RECEIVING AT THE TIME OF DEVELOPMENT OF RESISTANCE, WITH A MEDIAN DOSE OF 600 MG DAILY (RANGE, 400-800 MG). THE MEDIAN TIME FROM DIAGNOSIS OF CML TO THE START OF HYDRALAZINE AND VALPROATE WAS 53.6 MONTHS (RANGE, 19-84 MONTHS). TWO (25%) PATIENTS HAD A COMPLETE HEMATOLOGIC RESPONSE, ONE (12.5%) HAD AN MAJOR CYTOGENETIC RESPONSE, AND ONE (12.5%) HAD A COMPLETE CYTOGENETIC RESPONSE. THREE (37.5%) PATIENTS HAD STABLE DISEASE, AND ONLY ONE (12.5%) PATIENT FAILED TO RESPOND. AT A MEDIAN FOLLOW-UP TIME OF 18 MONTHS (RANGE, 3-18 MONTHS), THE MEDIAN SURVIVAL HAD NOT BEEN REACHED, AND THE PROJECTED OVERALL SURVIVAL WAS 63%. ALL THE PATIENTS HAD MILD NEUROLOGIC TOXICITY, INCLUDING DISTAL TREMOR AND SOMNOLENCE. NO GRADE 3 OR 4 TOXICITY WAS OBSERVED. CONCLUSIONS: OUR RESULTS SUGGEST THAT THE EPIGENETIC DRUGS HYDRALAZINE AND VALPROATE REVERT THE RESISTANCE TO IMATINIB IN PATIENTS WITH CML. 2012 16 3098 35 GENOMIC DISRUPTION OF THE HISTONE METHYLTRANSFERASE SETD2 IN CHRONIC LYMPHOCYTIC LEUKAEMIA. HISTONE METHYLTRANSFERASES (HMTS) ARE IMPORTANT EPIGENETIC REGULATORS OF GENE TRANSCRIPTION AND ARE DISRUPTED AT THE GENOMIC LEVEL IN A SPECTRUM OF HUMAN TUMOURS INCLUDING HAEMATOLOGICAL MALIGNANCIES. USING HIGH-RESOLUTION SINGLE NUCLEOTIDE POLYMORPHISM (SNP) ARRAYS, WE IDENTIFIED RECURRENT DELETIONS OF THE SETD2 LOCUS IN 3% (8/261) OF CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) PATIENTS. FURTHER VALIDATION IN TWO INDEPENDENT COHORTS SHOWED THAT SETD2 DELETIONS WERE ASSOCIATED WITH LOSS OF TP53, GENOMIC COMPLEXITY AND CHROMOTHRIPSIS. WITH NEXT-GENERATION SEQUENCING WE DETECTED MUTATIONS OF SETD2 IN AN ADDITIONAL 3.8% OF PATIENTS (23/602). IN MOST CASES, SETD2 DELETIONS OR MUTATIONS WERE OFTEN OBSERVED AS A CLONAL EVENT AND ALWAYS AS A MONO-ALLELIC LESION, LEADING TO REDUCED MRNA EXPRESSION IN SETD2-DISRUPTED CASES. PATIENTS WITH SETD2 ABNORMALITIES AND WILD-TYPE TP53 AND ATM FROM FIVE CLINICAL TRIALS EMPLOYING CHEMOTHERAPY OR CHEMO-IMMUNOTHERAPY HAD REDUCED PROGRESSION-FREE AND OVERALL SURVIVAL COMPARED WITH CASES WILD TYPE FOR ALL THREE GENES. CONSISTENT WITH ITS POSTULATED ROLE AS A TUMOUR SUPPRESSOR, OUR DATA HIGHLIGHT SETD2 ABERRATION AS A RECURRENT, EARLY LOSS-OF-FUNCTION EVENT IN CLL PATHOBIOLOGY LINKED TO AGGRESSIVE DISEASE. 2016 17 5275 37 PROMOTER METHYLATION OF THE BONE MORPHOGENETIC PROTEIN-6 GENE IN ASSOCIATION WITH ADULT T-CELL LEUKEMIA. BONE MORPHOGENETIC PROTEINS (BMP), BELONGING TO THE TRANSFORMING GROWTH FACTOR-BETA SUPERFAMILY, ARE MULTIFUNCTIONAL REGULATORS OF CELL PROLIFERATION, DIFFERENTIATION AND APOPTOSIS IN VARIOUS TYPES OF MALIGNANT CELLS. IN THIS STUDY, WE INVESTIGATED BMP-6 PROMOTER METHYLATION IN PATIENTS WITH VARIOUS TYPES OF LEUKEMIAS. THE BMP-6 METHYLATION WAS FOUND PREFERENTIALLY IN ADULT T-CELL LEUKEMIA (ATL) (49 OF 60, 82%) COMPARED WITH OTHER TYPES OF LEUKEMIAS STUDIED INCLUDING ACUTE MYELOID LEUKEMIA (3 OF 67, 5%), ACUTE LYMPHOBLASTIC LEUKEMIA (6 OF 38, 16%) AND CHRONIC LYMPHOCYTIC LEUKEMIA (1 OF 21, 5%). AMONG SUBTYPES OF ATL, THE BMP-6 GENE WAS MORE FREQUENTLY METHYLATED IN AGGRESSIVE ATL FORMS OF ACUTE (96%) AND LYMPHOMA (94%) TYPES THAN LESS MALIGNANT CHRONIC ATL (44%) AND SMOLDERING ATL (20%). WE ALSO ANALYZED THE METHYLATION STATUS OF PERIPHERAL BLOOD MONONUCLEAR CELLS FROM HEALTHY DONORS AND NONMALIGNANT LYMPH NODES WITH REACTIVE LYMPHADENOPATHY, NONE OF WHICH SHOWED DETECTABLE BMP-6 METHYLATION IN THIS STUDY. THE BMP-6 METHYALTION WAS CORRELATED WITH DECREASED MRNA TRANSCRIPT AND PROTEIN EXPRESSION. EXPRESSION OF BMP-6 WAS RESTORED BY THE DEMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE, SUGGESTING THAT METHYLATION WAS ASSOCIATED WITH THE TRANSCRIPTIONAL SILENCING. SERIAL ANALYSIS DEMONSTRATED AN INCREASING METHYLATION OF CPG SITES IN THE BMP-6 PROMOTER AND THE RESULTANT SUPPRESSION OF BMP-6 EXPRESSION AS ATL PROGRESSED. THESE FINDINGS SUGGESTED THAT BMP-6 PROMOTER METHYLATION IS LIKELY TO BE A COMMON EPIGENETIC EVENT AT LATER STAGES OF ATL AND THAT THE METHYLATION PROFILES MAY BE USEFUL FOR THE STAGING OF ATL AS WELL AS FOR EVALUATION OF THE INDIVIDUAL RISK OF DEVELOPING THE DISEASE. 2008 18 2262 35 EPIGENETIC PROFILING IN CHRONIC LYMPHOCYTIC LEUKEMIA REVEALS NOVEL METHYLATION TARGETS. CPG ISLAND METHYLATION IS AN EPIGENETIC ALTERATION THAT CONTRIBUTES TO TUMORIGENESIS BY TRANSCRIPTIONAL INACTIVATION OF GENES. LITTLE IS KNOWN ABOUT THE OVERALL LEVELS OF CPG ISLAND METHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). TO PROVIDE A BASELINE ESTIMATE OF GLOBAL ABERRANT METHYLATION AND IDENTIFY TARGET SEQUENCES FOR ADDITIONAL INVESTIGATION, WE PERFORMED RESTRICTION LANDMARK GENOMIC SCANNING ON 10 CLL SAMPLES. TWO METHYLATION-SENSITIVE LANDMARK ENZYMES WERE USED (NOTI AND ASCI), ALLOWING ASSESSMENT OF OVER 3000 CPG ISLANDS IN EACH SAMPLE. TUMOR-DERIVED RESTRICTION LANDMARK GENOMIC SCANNING PROFILES WERE COMPARED WITH PROFILES FROM CD19-SELECTED B CELLS FROM NORMAL VOLUNTEERS AND MATCHED NORMAL NEUTROPHILS FROM 4 CLL PATIENTS. WE FOUND 2.5-8.1% (MEAN 4.8%) OF THE CPG ISLANDS IN CLL SAMPLES WERE ABERRANTLY METHYLATED COMPARED WITH CONTROLS, AND THE METHYLATION EVENTS HAD A NONRANDOM DISTRIBUTION (P < 0.0001). FURTHERMORE, WE IDENTIFIED 193 ABERRANTLY METHYLATED SEQUENCES, OF WHICH 93% HAVE CPG ISLAND CHARACTERISTICS AND 90% HAVE HOMOLOGY TO GENES OR EXPRESSED SEQUENCES. ONE SUCH GENE, THE G PROTEIN-COUPLED METABOTROPIC GLUTAMATE RECEPTOR 7 (GRM7), POSSIBLY INHIBITS CYCLIC AMP SIGNALING IN THE INDUCTION OF APOPTOSIS. BISULFITE SEQUENCING OF GRM7 CONFIRMED EXTENSIVE CPG ISLAND METHYLATION, AND TREATMENT WITH 5-AZA-2'-DEOXYCYTIDINE (DECITABINE) RESULTED IN UP-REGULATED EXPRESSION OF SEVERAL GENES IN VITRO WITH CONCURRENT CELLULAR DEPLETION OF DNMT1 PROTEIN. OUR DUAL-ENZYME GLOBAL METHYLATION STUDY SHOWS THAT CLL IS CHARACTERIZED BY WIDESPREAD NONRANDOM CPG ISLAND METHYLATION SIMILAR TO OTHER TUMORS AND PROVIDES A PANEL OF NOVEL METHYLATION TARGETS THAT CAN BE USED IN LARGER STUDIES DESIGNED TO ASSESS IMPACT ON DISEASE PROGRESSION AND SURVIVAL. 2004 19 6249 32 THE METHYLATION STATUS OF THE MAJOR BREAKPOINT CLUSTER REGION IN HUMAN LEUKEMIA CELLS, INCLUDING PHILADELPHIA CHROMOSOME-POSITIVE CELLS, IS LINKED TO THE LINEAGE OF HEMATOPOIETIC CELLS. THE PHILADELPHIA (PH) TRANSLOCATION [T(9;22)(Q34;Q11)] IS THE MOST COMMON GENETIC ABNORMALITY IN HUMAN LEUKEMIA; A TRANSPOSITION OF THE ABL GENE TO THE MAJOR-BREAKPOINT CLUSTER REGION (M-BCR) IS ASSOCIATED WITH THE PATHOGENESIS IN PH+ CHRONIC MYELOGENOUS LEUKEMIA (PH+ CML) AND IN SOME CASES OF PH+ ACUTE LEUKEMIA (PH+ AL). OUR CURRENT UNDERSTANDING OF THE METHYLATION OF HUMAN GENOMES ALLOWS US TO CONSIDER THE ASSOCIATION BETWEEN THE EPIGENETIC PHENOMENON AND THE CONTROL OF DIFFERENTIATION AND PROLIFERATION IN MAMMALIAN CELLS. IN ORDER TO DETERMINE WHETHER THE METHYLATION STATUS OF THE M-BCR IS ASSOCIATED WITH BREAKPOINT-LOCALIZATION IN THIS REGION AND WITH THE LINEAGE OF HEMATOPOIETIC CELLS, WE HAVE EXAMINED 28 PATIENTS WITH PH+ LEUKEMIAS, INCLUDING NINE WITH PH+ AL, SIX PATIENTS WITH ACUTE MYELOBLASTIC LEUKEMIA WITHOUT PH (PH- AML), AND FIVE PATIENTS WITH PH- ACUTE LYMPHOBLASTIC LEUKEMIA (PH- ALL); USING THE RESTRICTION ENDONUCLEASE ISOCHIZOMERS, MSPI AND HPAII. IN CML PATIENTS IN THE CHRONIC PHASE, THE HYPOMETHYLATED STATUS WITHIN THE NORMAL M-BCR ALLELE IS HETEROGENEOUS. IN CONTRAST, PATIENTS WITH PH+ CML IN THE LYMPHOID BLAST CRISIS PHASE EXHIBITED A 2.5/2.7 KB BAND WITH A COMPLETE DISAPPEARANCE OF THE GERMLINE M-BCR FRAGMENT (TYPE L). THIS PATTERN IS CONSISTENTLY NOTED IN PH- ALL CELLS, AND THE PATTERN IS QUITE DIFFERENT FROM THAT FOUND IN MYELOID BLAST CRISIS OR PH- AML (TYPE M). IN PATIENTS WITH M-BCR-NONREARRANGED PH+ ALL, IT IS SUGGESTED THAT THE M-BCR METHYLATION PATTERNS ARE CELL-LINEAGE SPECIFIC BUT SOME PH+ ALL CELLS HAD A HYPOMETHYLATION PATTERN THAT WAS IDENTICAL TO THAT OBSERVED IN PH- AML, SUGGESTING A DISTINCTION OF GENETIC DIVERSITY OF LEUKEMIA CELLS WITH THE PH CHROMOSOME, ESPECIALLY PH+ AL. 1993 20 2753 29 EXPRESSION OF BCL2L12 IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS: ASSOCIATION WITH CLINICAL AND MOLECULAR PROGNOSTIC MARKERS. DYSREGULATION OF APOPTOSIS IS A DISTINCTIVE FEATURE OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), ALTHOUGH A UNIQUE MECHANISM UNDERLYING APOPTOSIS RESISTANCE OF CLL B LYMPHOCYTES HAS NOT BEEN IDENTIFIED YET. ABERRANT EXPRESSION AS WELL AS GENETIC AND EPIGENETIC ALTERATIONS OF NUMEROUS GENES INVOLVED IN DIFFERENT PATHWAYS OF APOPTOSIS REGULATION HAS BEEN DESCRIBED IN CLL. HERE, WE REPORT THE EXPRESSION ANALYSIS OF BCL2L12 (BCL2-LIKE 12), A NOVEL APOPTOTIC GENE BELONGING TO BCL2 FAMILY, IN 58 SERBIAN CLL PATIENTS. QUANTITATIVE REVERSE-TRANSCRIPTASE POLYMERASE CHAIN REACTION (QRT-PCR) ANALYSIS REVEALED A SIGNIFICANT OVEREXPRESSION OF BCL2L12 MRNA IN CLL SAMPLES COMPARED TO NON-LEUKEMIC SAMPLES, IMPLYING ITS ROLE IN THE PATHOGENESIS OF THE DISEASE. RECEIVER OPERATING CHARACTERISTIC (ROC) ANALYSIS SHOWED THAT BCL2L12 EXPRESSION EFFICIENTLY DISCRIMINATES CLL CASES FROM HEALTHY CONTROLS. HOWEVER, RELATIVELY HOMOGENOUS BCL2L12 MRNA EXPRESSION AMONG PATIENTS DID NOT REFLECT THEIR CLINICAL CHARACTERISTICS (WITH THE EXCEPTION OF LACTATE DEHYDROGENASE STATUS AND TIME FROM DIAGNOSIS TO TREATMENT) AND FAILED TO SHOW ASSOCIATION WITH THE MOST INFORMATIVE PROGNOSTIC MARKERS, NAMELY THE MUTATIONAL STATUS OF REARRANGED IMMUNOGLOBULIN HEAVY CHAIN VARIABLE REGION GENES, CD38 AND LIPOPROTEIN LIPASE GENE (LPL) EXPRESSION. 2013