1 2904 95 GENE BODY METHYLATION FACILITATES THE TRANSCRIPTION OF CTSG VIA ANTISENSE LNCRNA AL136018.1 IN DERMATOMYOSITIC MYOIDEUM. DERMATOMYOSITIS (DM) IS CHARACTERIZED AS A CHRONIC AUTOIMMUNE DISORDER WITH MULTIPLE ORGAN INVOLVEMENT. OUR PREVIOUS STUDY HAS REVEALED THAT CATHEPSIN G (CTSG) HIGHLY EXPRESSED IN DERMATOMYOSITIC IN VIVO IS REGULATED BY DNMT3A THROUGH DNA METHYLATION OF 5'-C-PHOSPHATE-G-3' LOCI AT EXONS AND INTRONS. HOWEVER, THE MECHANISM OF GENE BODY METHYLATION ON REGULATING CTSG TRANSCRIPTION REMAINS UNKNOWN. IN THIS STUDY, WE STUDIED QUADRICEPS FEMORIS TISSUES OF SIX DM PATIENTS, AND OBSERVED THAT ANTISENSE LONG NONCODING RNA AL136018.1 CONTIGUOUS TO CTSG WAS HIGHLY EXPRESSED IN SKELETAL MUSCLE TISSUES OF DM AND POSITIVELY CORRELATED WITH THE TRANSCRIPTION LEVEL AND DNA METHYLATION LEVEL IN GENE BODY OF CTSG IN VIVO. MOREOVER, WE OBSERVED THAT THE LONGER TRANSCRIPT OF AL136018.1 (AL136018.1-201) COULD BIND TO THIRD AND FOURTH EXONS AND THIRD INTRON OF CTSG VIA THE 3'-END. FINALLY, AL136018.1-201 COULD RECRUIT DNMT3A TOWARDS GENE BODY VIA 5'-TERMINAL FOR ADDING DNA METHYLATION AND FACILITATING TRANSCRIPTION OF CTSG. TAKEN TOGETHER, OUR DATA UNCOVERED A NOVEL EPIGENETIC MECHANISM BEHIND THE GENE BODY METHYLATION FOR TRANSCRIPTIONAL REGULATION OF CTSG IN DM. 2021 2 5542 56 ROLE OF DNA METHYLATION ON HUMAN CTSG IN DERMATOMYOSITIC MYOIDEUM. DERMATOMYOSITIS (DM) IS A MULTIFACTORIAL CHRONIC AUTOIMMUNE DISORDER WITH CHARACTERISTIC SKIN AND MUSCLE PATHOLOGICAL CHANGES AND INVOLVEMENT OF OTHER ORGAN SYSTEMS. CATHEPSIN G (CTSG) CONTRIBUTES TO THE RISK OF DEVELOPING DM, WHICH IS LIKELY TO BE ASSOCIATED WITH INFLAMMATORY CYTOKINES. DIFFERENTIAL DNA METHYLATION ON CTSG HAS BEEN DETERMINED TO BE IMPLICATED IN DM IN VIVO. HOWEVER, THE UNDERLYING MECHANISM OF THIS EPIGENETIC REGULATION ON CTST IN DM IS POORLY EXPLORED. IN THIS STUDY, WE INVESTIGATED DNA METHYLATION SIGNATURE ON CTSG AT SINGLE-NUCLEOTIDE RESOLUTION IN QUADRICEPS FEMORIS OF SIX DM PATIENTS AND PARACANCEROUS MUSCLES OF THREE PATIENTS WITH RHABDOMYOSARCOMA ON INNER THIGH USING PYROSEQUENCING AND OBSERVED THAT THE OVERALL DNA METHYLATION LEVEL OF CTSG WAS INCREASED IN DM COMPARED WITH CONTROL, IN WHICH CPG LOCI AT THIRD AND FOURTH EXONS BUT NOT PROMOTER CONTRIBUTED TO THE SIGNIFICANT HYPERMETHYLATION. FURTHERMORE, WE OBSERVED THAT TRANSCRIPTION AND DNA METHYLATION OF CTSG WERE BOTH DECLINED IN DNMT3A KNOCKDOWN COMPARED WITH DNMT1 AND DNMT3B KNOCKDOWN IN HUMAN SKELETAL MUSCLE SJCRH30 AND A-204 CELL LINES EXPOSED TO TUMOR NECROSIS FACTOR-ALPHA. FURTHERMORE, BORTEZOMIB (NF-KAPPAB INHIBITOR) AND BREVILIN A (JAK/STAT INHIBITOR) WERE EMPLOYED TO TREAT SJCRH30 AND A-204 CELLS, RESPECTIVELY, AND WE OBSERVED THAT CTSG WAS HYPOMETHYLATED AND SILENCED AFTER BORTEZOMIB TREATMENT COMPARED WITH UNTREATMENT AND BREVILIN A. FINALLY, CHROMATIN IMMUNOPRECIPITATION-QUANTITATIVE POLYMERASE CHAIN REACTION INDICATED THAT DNMT3A COULD BIND TO THE CODING REGIONS OF CTSG AND THE INTERACTION WAS DEPENDENT ON NF-KAPPAB ACTIVITY. TAKEN TOGETHER, OUR RESULTS DETERMINED A NOVEL REGULATORY MECHANISM OF DNA METHYLATION ON CTSG IN DM. 2020 3 6079 22 THE EFFECT OF CXCL12 PROCESSING ON CD34+ CELL MIGRATION IN MYELOPROLIFERATIVE NEOPLASMS. PRIMARY MYELOFIBROSIS (PMF) AND POLYCYTHEMIA VERA (PV) ARE CHRONIC MYELOPROLIFERATIVE NEOPLASMS. PMF AND, TO A LESSER DEGREE, PV ARE CHARACTERIZED BY CONSTITUTIVE MOBILIZATION OF HEMATOPOIETIC STEM CELLS (HSC) AND PROGENITOR CELLS (HPC) INTO THE PERIPHERAL BLOOD (PB). THE INTERACTION BETWEEN THE CHEMOKINE CXCL12 AND ITS RECEPTOR CXCR4 PLAYS A PIVOTAL ROLE IN DETERMINING THE TRAFFICKING OF CD34(+) CELLS BETWEEN THE BONE MARROW (BM) AND THE PB. PMF, BUT NOT PV, IS ASSOCIATED WITH DOWNREGULATION OF CXCR4 BY CD34(+) CELLS DUE TO EPIGENETIC EVENTS. BOTH PV AND PMF PATIENTS HAVE ELEVATED LEVELS OF IMMUNOREACTIVE FORMS OF CXCL12 IN THE BM AND PB. USING ELECTROSPRAY MASS SPECTROMETRY, THE PB AND BM PLASMA OF PV AND PMF PATIENTS WAS SHOWN TO CONTAIN REDUCED AMOUNTS OF INTACT CXCL12 BUT SIGNIFICANT AMOUNTS OF SEVERAL TRUNCATED FORMS OF CXCL12, WHICH ARE LACKING IN NORMAL PB AND BM PLASMA. THESE TRUNCATED FORMS OF CXCL12 ARE THE PRODUCT OF THE ACTION OF SEVERAL SERINE PROTEASES, INCLUDING DIPEPTIDYL PEPTIDASE-IV, NEUTROPHIL ELASTASE, MATRIX METALLOPROTEINASE-2 (MMP-2), MMP-9, AND CATHEPSIN G. UNLIKE CXCL12, THESE TRUNCATES EITHER LACK THE ABILITY TO ACT AS A CHEMOATTRACTANT FOR CD34(+) CELLS AND/OR ACT AS AN ANTAGONIST TO THE ACTION OF CXCL12. THESE DATA SUGGEST THAT PROTEOLYTIC DEGRADATION OF CXCL12 IS CHARACTERISTIC OF BOTH PV AND PMF AND THAT THE RESULTING TRUNCATED FORMS OF CXCL12, IN ADDITION TO THE REDUCED EXPRESSION OF CXCR4 BY CD34(+) CELLS, LEAD TO A PROFOUND MOBILIZATION OF HSC/HPC IN PMF. 2010 4 4117 24 MECHANISMS OF AUTOPHAGIC RESPONSES TO ALTERED NUTRITIONAL STATUS. AUTOPHAGY IS A DYNAMIC PROCESS AND CRITICAL FOR CELLULAR REMODELING AND ORGANELLE QUALITY CONTROL. IN RESPONSE TO ALTERED NUTRITIONAL STATUS (E.G., FASTING AND FEEDING), AUTOPHAGIC ACTIVITY IS FINELY TUNED BY TRANSCRIPTIONAL, POSTTRANSLATIONAL, AND EPIGENETIC REGULATIONS VIA VARIOUS SIGNALING PATHWAYS, INCLUDING ENERGY SENSORS (E.G., MECHANISTIC TARGET OF RAPAMYCIN (MTOR)/ AMP-ACTIVATED PROTEIN KINASE - UNC-51 LIKE AUTOPHAGY ACTIVATING KINASE 1, MTORC1- WD REPEAT DOMAIN, PHOSPHOINOSITIDE INTERACTING 2, MTORC1- TRANSCRIPTION FACTOR EB, PERILIPIN 5- SIRTUIN 1, AND SIRTUIN 1-MEDIATED DEACETYLATION OF AUTOPHAGY PROTEINS), FASTING OR FEEDING INDUCED HORMONES (E.G., FIBROBLAST GROWTH FACTOR [FGF21]- PROTEIN KINASE A - JUMONJI DOMAIN-CONTAINING PROTEIN D3, FGF21- DOWNSTREAM REGULATORY ELEMENT ANTAGONIST MODULATOR - E3 LIGASE MIDLINE-1- TRANSCRIPTION FACTOR EB, FGF19-SHP- LYSINE-SPECIFIC DEMETHYLASE, INSULIN- INSULIN RECEPTOR SUBSTRATE - PROTEIN KINASE B - FORKHEAD BOX O, GLUCAGON- PROTEIN KINASE A - CAMP RESPONSE BINDING PROTEIN), AND LYSOSOMAL ENZYMES (E.G., CATHEPSIN B AND CATHEPSIN L). IN CONTRAST TO FASTING THAT INDUCES AUTOPHAGY AND HEALTH BENEFITS, NUTRIENT OVERSUPPLY (OVERFEEDING OR FEEDING ON HIGH ENERGY DIETS) DYSREGULATES AUTOPHAGY, WHICH HAS BEEN INCREASINGLY OBSERVED IN ANIMAL MODELS OF HUMAN CHRONIC DISEASES SUCH AS OBESITY, DIABETES, NON-ALCOHOLIC FATTY LIVER DISEASE, AND CARDIOVASCULAR DISEASE. STUDIES HAVE REVEALED MULTIFACETED EFFECTS OF HIGH ENERGY DIETS ON AUTOPHAGY, BEING EITHER AN INHIBITOR OR ENHANCER OF AUTOPHAGY. THE CONUNDRUM MAY ARISE FROM THE VARIATIONS IN METHODS FOR AUTOPHAGY ANALYSIS, COMPONENTS OF HIGH ENERGY DIETS AND CONTROL DIETS FOR TREATMENTS, TREATMENT DURATIONS, AND THE AGES OF GENETIC BACKGROUNDS OF LABORATORY ANIMALS. IN THIS ARTICLE, WE REVIEWED THE EVIDENCE FROM BOTH HUMAN AND ANIMAL STUDIES, PRESENTING THE MOLECULAR MECHANISM OF AUTOPHAGIC RESPONSE TO ALTERED NUTRITIONAL STATUS AND DISCUSSING THE CONTRIBUTING FACTORS OF AND POSSIBLE SOLUTION TO THE CURRENT CONUNDRUM CONCERNING THE EXACT ROLE OF HIGH ENERGY DIETS IN AUTOPHAGIC REGULATION. 2022 5 5459 27 RESEARCH ON THE EPIGENETIC REGULATION MECHANISM OF THE PTPN6 GENE IN ADVANCED CHRONIC MYELOID LEUKAEMIA. PTPN6, A TYROSINE PHOSPHATASE PROTEIN, PLAYS A NEGATIVE ROLE IN CELL SIGNAL TRANSDUCTION AND IS NEGATIVELY CORRELATED WITH TUMOUR FORMATION AND GROWTH. HOWEVER, EPIGENETIC REGULATION MECHANISM OF THE PTPN6 GENE IN ADVANCED CHRONIC MYELOID LEUKAEMIA (CML) REMAINS UNCLEAR. THIS STUDY INVESTIGATED BONE MARROW OR BLOOD SAMPLES FROM 44 CML PATIENTS AND 10 HEALTHY VOLUNTEERS. KCL22 AND K562 CELLS WERE CULTURED AND TREATED WITH DEMETHYLATION DRUGS AND HISTONE DEACETYLASE INHIBITORS. REAL TIME QUANTITATIVE POLYMERASE CHAIN REACTION (QPCR), METHYLATION-SPECIFIC PCR, BISULFITE SEQUENCING PCR, WESTERN BLOTTING, CO-IMMUNOPRECIPITATION AND CHROMATIN IMMUNOPRECIPITATION (CHIP) WAS PERFORMED. PTPN6 WAS DOWN-REGULATED IN CELL LINES AND PATIENTS WITH ADVANCED PHASE CML, WHEREAS DNMT1, DNMT3A, MECP2, MBD2 AND HDAC1 WERE UP-REGULATED. TREATMENT WITH 5-AZACYTIDINE, DECITABINE, SODIUM VALPROATE AND LBH589 INCREASED PTPN6 EXPRESSION, BUT DECREASED THAT OF DNMT1, DNMT3A, MECP2, MBD2 AND HDAC1. IMMUNOPRECIPITATION AND MASS SPECTROMETRY SHOWED THAT HDAC1 COMBINED DIRECTLY WITH PTPN6. CHIP-SEQ SHOWED THAT HDAC1 DID NOT COMBINE WITH THE PROMOTER REGION OF PTPN6, WHILE MAPK, AKT, STAT5, JAK2 AND MYC PROMOTER REGIONS ALL COMBINED WITH HDAC1. PTPN6 IS ASSOCIATED WITH PROGRESSION OF CML. LOW EXPRESSION LEVEL OF PTPN6 WAS ASSOCIATED WITH DNA METHYLATION AND REGULATED BY HISTONE ACETYLATION. HDAC1 PARTICIPATES IN THE REGULATION OF PTPN6. 2017 6 2326 27 EPIGENETIC REGULATION OF HOTAIR IN ADVANCED CHRONIC MYELOID LEUKEMIA. PURPOSE: CHRONIC MYELOID LEUKEMIA (CML) ACCOUNTS FOR ~10% OF LEUKEMIA CASES, AND ITS PROGRESSION INVOLVES EPIGENETIC GENE REGULATION. THIS STUDY INVESTIGATED EPIGENETIC REGULATION OF HOTAIR AND ITS TARGET MICRORNA, MIR-143, IN ADVANCED CML. PATIENTS AND METHODS: WE FIRST ISOLATED BONE MARROW MONONUCLEAR CELLS FROM 70 PATIENTS WITH DIFFERENT PHASES OF CML AND FROM HEALTHY DONORS AS NORMAL CONTROL; WE ALSO CULTURED K562 AND KCL22 CELLS, TREATED WITH DEMETHYLATION DRUG; MTT ASSAY, FLOW CYTOMETRY, QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (QPCR), METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (MSP), WESTERN BLOT, LUCIFERASE ASSAY, RNA PULL-DOWN ASSAY AND RNA-BINDING PROTEIN IMMUNOPRECIPITATION (RIP) ASSAY WERE PERFORMED. RESULT: AS MEASURED BY QPCR, HOTAIR EXPRESSION IN K562 CELLS, KCL22 CELLS, AND SAMPLES FROM CASES OF ADVANCED-STAGE CML INCREASED WITH LEVELS OF SEVERAL DNA METHYLTRANSFERASES AND HISTONE DEACETYLATES, INCLUDING DNMT1, DNMT3A, HDAC1, EZH2, AND LSD1, AND MIR-143 LEVELS WERE DECREASED AND HOTAIR LEVELS WERE INCREASED. TREATMENT WITH 5-AZACYTIDINE, A DNA METHYLATION INHIBITOR, DECREASED DNMT1, DNMT3A, HDAC1, EZH2, LSD1 MRNA, PROTEIN LEVELS, AND HOTAIR MRNA LEVELS BUT INCREASED MIR-143 LEVELS. HOTAIR KNOCKDOWN AND MIR-143 OVEREXPRESSION BOTH INHIBITED PROLIFERATION AND PROMOTED APOPTOSIS IN KCL22 AND K562 CELLS THROUGH THE PI3K/AKT PATHWAY. RNA PULL-DOWN, MASS SPECTROMETRY, AND RIP ASSAYS SHOWED THAT HOTAIR INTERACTED WITH EZH2 AND LSD1. A DUAL-LUCIFERASE ASSAY DEMONSTRATED THAT HOTAIR INTERACTED WITH MIR-143. CONCLUSION: OUR FINDINGS DEMONSTRATE THE KEY EPIGENETIC INTERACTIONS OF HOTAIR RELATED TO CML PROGRESSION AND SUGGEST HOTAIR AS A POTENTIAL THERAPEUTIC TARGET FOR ADVANCED CML. FURTHERMORE, OUR RESULTS SUPPORT THE USE OF DEMETHYLATION DRUGS AS A CML TREATMENT STRATEGY. 2018 7 6793 24 [DOWN-REGULATION OF TRANSCRIPTION FACTOR PU.1 VIA ABNORMAL EPIGENETIC MODIFICATION IN CHRONIC MYELOID LEUKEMIA]. OBJECTIVE: TO INVESTIGATE THE UNDERLYING MECHANISM AND CLINICAL SIGNIFICANCE OF PU.1 DOWN-EXPRESSION IN CHRONIC MYELOID LEUKEMIA (CML) PATIENTS. METHODS: DIFFERENT METHYLATION STATUS OF PU.1 PROMOTER REGION CONTAINING 20 CPG ISLANDS IN NORMAL INDIVIDUALS, CML CHRONIC PHASE AND BLAST CRISIS PATIENTS, COMPLETE CYTOGENETIC REMISSION PATIENTS AFTER IMATINIB TREATMENT, AND BLAST CRISIS BONE MARROW K562 CML CELLS WAS DETECTED BY BISULFITE SEQUENCING. SEMI-QUANTITATIVE PCR WAS USED TO DETECT THE PU.1 MRNA EXPRESSION IN NORMAL CONTROLS, CML CHRONIC PHASE AND BLAST CRISIS PATIENTS, AND BLAST CRISIS BONE MARROW K562 CML CELLS. INDIRECT IMMUNE FLUORESCENCE AND WESTERN BLOT WERE USED TO ANALYZE THE EXPRTESSION OF PU.1 PROTEIN IN NORMAL INDIVIDUALS, CML CHRONIC PHASE AND BLAST CRISIS PATIENTS, AND BLAST CRISIS BONE MARROW K562 CML CELLS. RESULTS: ABERRANT METHYLATION IN THE PROMOTER REGION OF TRANSCRIPTION FACTOR PU.1 WAS FOUND IN BOTH CML CHRONIC PHASE AND BLAST CRISIS PHASE BONE MARROW CELLS, AS WELL AS IN CML BLAST K562 CELLS. DOWN-EXPRESSION OF PU.1 MRNA AND PROTEIN LEVELS WAS FOUND IN ABOVE CELLS. NO METHYLATION IN THE PROMOTER REGION OF PU.1 WAS OBSERVED IN NORMAL INDIVIDUALS, AND THE PU.1 MRNA AND PROTEIN EXPRESSIONS WERE NOT REDUCED AT ALL. FURTHERMORE, HIGH METHYLATION STATUS OF BONE MARROW CELLS WAS EVEN OBSERVED IN THE CML PATIENTS WHO ACQUIRED COMPLETE CYTOGENETIC REMISSION. CONCLUSIONS: THE RESULTS OF OUR STUDY INDICATE THAT THE EPIGENETIC MODIFICATION OF PU.1 IN CML PATIENTS AND K562 CELL LINE MIGHT BE RESPONSIBLE FOR THE DOWN-EXPRESSION OF PU.1. THE DATA SUGGEST THAT ABERRANT METHYLATION OF PU.1 PLAYS A ROLE IN CML PATHOGENESIS, THEREFORE, IT MIGHT SERVE AS A USEFUL BIOMARKER AND POTENTIAL TARGET IN THERAPY FOR CHRONIC MYELOID LEUKEMIA. 2012 8 6231 28 THE LONG NONCODING RNA MEG3 AND ITS TARGET MIR-147 REGULATE JAK/STAT PATHWAY IN ADVANCED CHRONIC MYELOID LEUKEMIA. BACKGROUND: LONG NON-CODING (LNC) RNAS PLAYS AN IMPORTANT ROLE IN CHRONIC MYELOID LEUKEMIA (CML). IN THIS STUDY, WE AIMED TO UNCOVER THE MECHANISM OF THE LNCRNA MATERNALLY EXPRESSED 3 (MEG3) AND ITS TARGET MICRORNA-147 (MIR-147) IN CML. METHODS: SIXTY CML PATIENTS AND 10 HEALTHY DONORS WERE INCLUDED IN THE STUDY. THE METHYLATION OF MEG3 AND MIR-147 PROMOTER WAS DETERMINED BY METHYLATION-SPECIFIC PCR. THE RELATIONSHIP OF MEG3 AND MIR-147 WAS EXPLORED BY LUCIFERASE ASSAY. THE INTERACTIONS OF PROTEINS WERE STUDIED BY RNA PULL-DOWN ASSAY, RNA IMMUNOPRECIPITATION AND CO-IMMUNOPRECIPITATION. FINDINGS: PATIENTS IN ACCELERATED PHASE CML (CML-AP) AND BLAST PHASE CML (CML-BP) SHOWED LOWER EXPRESSIONS OF MEG3 AND MIR-147 AND HIGHER EXPRESSIONS OF DNMT1, DNMT3B, MBD2, MECP2 AND HDAC1 COMPARED TO THE CONTROLS. THESE PATIENTS ALSO SHOWED A HIGHER DEGREE OF METHYLATION OF MEG3 AND MIR-147 WHILE THERE WAS A REDUCTION AFTER CHIDAMIDE TREATMENT. FURTHERMORE, THE OVEREXPRESSION OF MEG3 AND MIR-147 INHIBITED CELL PROLIFERATION BOTH IN VIVO AND IN VITRO, PROMOTED APOPTOSIS AND DECREASED THE EXPRESSIONS OF DNMT1, DNMT3A, DNMT3B, MBD2, HDAC1 AND MECP2. WE ALSO FOUND MEG3 INTERACTED WITH DNMT1, JAK2, STAT3, HDAC1, AND TYK2, AND JAK2 WAS BOUND TO STAT3, STAT5 AND MYC. MORE INTERESTINGLY, JAK2 WAS BOUND TO TYK2 BY THE BRIDGE OF MEG3. INTERPRETATION: LNCRNA MEG3 AND ITS TARGET MIR-147 MAY SERVE AS A NOVEL THERAPEUTIC TARGET FOR CML BLAST CRISIS, AND CHIDAMIDE MIGHT HAVE A POTENTIAL CLINICAL APPLICATION IN TREATING CML BLAST CRISIS. 2018 9 4245 29 METHYLATION STATUS OF DDIT3 GENE IN CHRONIC MYELOID LEUKEMIA. BACKGROUND: DNA-DAMAGE-INDUCIBLE TRANSCRIPT 3 (DDIT3), A CANDIDATE TUMOR SUPPRESSOR GENE (TSG), HAS BEEN FOUND INVOLVED IN THE REGULATION OF CELLULAR GROWTH AND DIFFERENTIATION. THE EPIGENETIC CHANGES OF TSGS ARE RECENTLY RECOGNIZED AS AN ABNORMAL MECHANISM CONTRIBUTING TO THE DEVELOPMENT OF CHRONIC MYELOID LEUKEMIA (CML). THE AIM OF THIS STUDY WAS TO INVESTIGATE THE METHYLATION STATUS OF DDIT3 GENE IN CML PATIENTS. METHODS: THE METHYLATION STATUS OF DDIT3 PROMOTER WAS DETECTED IN THE BONE MARROW MONONUCLEAR CELLS FROM 53 PATIENTS WITH CML USING METHYLATION-SPECIFIC PCR (MSP). THE EXPRESSION LEVELS OF DDIT3 AND BCR/ABL TRANSCRIPT WERE DETERMINED BY REAL-TIME QUANTITATIVE PCR (RQ-PCR). CLINICAL DATA OF THESE PATIENTS WERE COLLECTED AND ANALYZED. RESULTS: THE ABERRANT METHYLATION OF DDIT3 GENE PROMOTER WAS FOUND IN 35 OF 53 (66%) CML CASES. CORRELATION WAS NOT FOUND BETWEEN DDIT3 PROMOTER HYPERMETHYLATION AND THE AGE, SEX, HEMOGLOBIN CONCENTRATION, PLATELET COUNTS, CHROMOSOMAL ABNORMALITIES, BCR/ABL TRANSCRIPT, AND STAGING OF CML PATIENTS (P > 0.05), BUT FOUND BETWEEN DDIT3 PROMOTER HYPERMETHYLATION AND WBC COUNTS OF CML CASES (R = 0.781, P < 0.001). THE LEVEL OF DDIT3 TRANSCRIPT IN CML PATIENTS WAS SIGNIFICANTLY LOWER THAN THAT IN CONTROLS (MEDIAN 3.28 VS 19.69, P < 0.001), HOWEVER, THERE WAS NO DIFFERENCE IN THE LEVEL OF DDIT3 TRANSCRIPT BETWEEN METHYLATION-POSITIVE CML CASES (0.05-65.32, MEDIAN 2.13) AND METHYLATION- NEGATIVE CML CASES (0.12-126.04, MEDIAN 3.92) (P > 0.05). CONCLUSION: OUR RESULTS DEMONSTRATE THAT ABERRANT METHYLATION OF DDIT3 OCCURS IN CML FREQUENTLY. 2010 10 2304 27 EPIGENETIC REGULATION OF CATHEPSIN L EXPRESSION IN CHRONIC MYELOID LEUKAEMIA. THE EXPRESSION AND SIGNIFICANCE OF CATHEPSIN L (CTSL) HAS BEEN EXTENSIVELY STUDIED IN SOLID TUMOURS. HOWEVER NO SUCH INFORMATION IN CHRONIC MYELOID LEUKAEMIA (CML) WAS AVAILABLE. WE INVESTIGATED THE ACTIVITY AND EXPRESSION OF THIS PROTEASE IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) OF 47 ADULT CML PATIENTS. THIRTY ADULTS SUFFERING FROM SYSTEMIC DISEASES AND 50 HEALTHY VOLUNTEERS SERVED AS CONTROLS. THE MRNA LEVELS OF CTSL, ITS SPECIFIC ENDOGENOUS INHIBITOR CYSTATIN C AND TRANSCRIPTIONAL UP-REGULATOR VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF) WERE QUANTITATED BY REAL-TIME QPCR. CTSL PROTEASE ACTIVITY AND ITS MRNA EXPRESSION WERE SIGNIFICANTLY HIGHER IN CML CHRONIC PHASE (CP) PATIENTS COMPARED TO CML ACCELERATED PHASE/BLAST CRISIS (AP/BC) PATIENTS AND CONTROLS (P