1 1333 149 DEREGULATION AND EPIGENETIC MODIFICATION OF BCL2-FAMILY GENES CAUSE RESISTANCE TO VENETOCLAX IN HEMATOLOGIC MALIGNANCIES. THE BCL2 INHIBITOR VENETOCLAX HAS BEEN APPROVED TO TREAT DIFFERENT HEMATOLOGICAL MALIGNANCIES. BECAUSE THERE IS NO COMMON GENETIC ALTERATION CAUSING RESISTANCE TO VENETOCLAX IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) AND B-CELL LYMPHOMA, WE ASKED IF EPIGENETIC EVENTS MIGHT BE INVOLVED IN VENETOCLAX RESISTANCE. THEREFORE, WE EMPLOYED WHOLE-EXOME SEQUENCING, METHYLATED DNA IMMUNOPRECIPITATION SEQUENCING, AND GENOME-WIDE CLUSTERED REGULARLY INTERSPACED SHORT PALINDROMIC REPEATS (CRISPR)/CRISPR-ASSOCIATED PROTEIN 9 SCREENING TO INVESTIGATE VENETOCLAX RESISTANCE IN AGGRESSIVE LYMPHOMA AND HIGH-RISK CLL PATIENTS. WE IDENTIFIED A REGULATORY CPG ISLAND WITHIN THE PUMA PROMOTER THAT IS METHYLATED UPON VENETOCLAX TREATMENT, MEDIATING PUMA DOWNREGULATION ON TRANSCRIPT AND PROTEIN LEVEL. PUMA EXPRESSION AND SENSITIVITY TOWARD VENETOCLAX CAN BE RESTORED BY INHIBITION OF METHYLTRANSFERASES. WE CAN DEMONSTRATE THAT LOSS OF PUMA RESULTS IN METABOLIC REPROGRAMMING WITH HIGHER OXIDATIVE PHOSPHORYLATION AND ADENOSINE TRIPHOSPHATE PRODUCTION, RESEMBLING THE METABOLIC PHENOTYPE THAT IS SEEN UPON VENETOCLAX RESISTANCE. ALTHOUGH PUMA LOSS IS SPECIFIC FOR ACQUIRED VENETOCLAX RESISTANCE BUT NOT FOR ACQUIRED MCL1 RESISTANCE AND IS NOT SEEN IN CLL PATIENTS AFTER CHEMOTHERAPY-RESISTANCE, BAX IS ESSENTIAL FOR SENSITIVITY TOWARD BOTH VENETOCLAX AND MCL1 INHIBITION. AS WE FOUND LOSS OF BAX IN RICHTER'S SYNDROME PATIENTS AFTER VENETOCLAX FAILURE, WE DEFINED BAX-MEDIATED APOPTOSIS TO BE CRITICAL FOR DRUG RESISTANCE BUT NOT FOR DISEASE PROGRESSION OF CLL INTO AGGRESSIVE DIFFUSE LARGE B-CELL LYMPHOMA IN VIVO. A COMPOUND SCREEN REVEALED TRAIL-MEDIATED APOPTOSIS AS A TARGET TO OVERCOME BAX DEFICIENCY. FURTHERMORE, ANTIBODY OR CAR T CELLS ELIMINATED VENETOCLAX RESISTANT LYMPHOMA CELLS, PAVING A CLINICALLY APPLICABLE WAY TO OVERCOME VENETOCLAX RESISTANCE. 2022 2 479 44 ARSENIC TRIOXIDE INHIBITS DNA METHYLTRANSFERASE AND RESTORES TMS1 GENE EXPRESSION IN K562 CELLS. BACKGROUND: GENE SILENCING ASSOCIATED WITH ABERRANT METHYLATION OF PROMOTER REGION CPG ISLANDS IS AN ACQUIRED EPIGENETIC ALTERATION THAT SERVES AS AN ALTERNATIVE TO GENETIC DEFECTS IN THE INACTIVATION OF TUMOR SUPPRESSOR GENES IN HUMAN CANCERS. THE DEMETHYLATING, DOSE-DEPENDENT EFFECT OF ARSENIC TRIOXIDE (AS2O3) ON SEVERAL TUMOR-RELATED GENES HAS ALREADY BEEN POSTULATED. HOWEVER, WHETHER SUCH A DEMETHYLATING EFFECT ALSO APPLIES TO THE TMS1 GENE IN CHRONIC MYELOID LEUKEMIA CELL LINE K562 CELLS HAS NOT BEEN STUDIED SO FAR. THE AIM OF THE PRESENT STUDY WAS TO DETECT THE METHYLATION STATUS OF THE TMS1 GENE IN K562 CELLS AND THE DEMETHYLATION EFFECT OF AS2O3 ON TMS1 AS WELL AS TMS1 APOPTOSIS-ASSOCIATED PROTEIN BCL-2/BAX AND DNA METHYLTRANSFERASE (DNMT) EXPRESSION. METHODS: TMS1 MRNA EXPRESSION IN K562 CELLS AND NORMAL BONE MARROW WAS DETERMINED BY REVERSE TRANSCRIPTION (RT) POLYMERASE CHAIN REACTION (PCR), AND THE DNA METHYLATION STATUS OF THE TMS1 PROMOTER IN K562 CELLS TREATED WITH DIFFERENT CONCENTRATIONS OF AS2O3 FOR 48 H WAS DETERMINED BY METHYLATION-SPECIFIC PCR. RT-PCR AND WESTERN BLOT WERE USED TO DETECT TMS1 AND DNMT EXPRESSION. WE ALSO ASSESSED TMS1-ASSOCIATED APOPTOSIS PROTEIN BCL-2/BAX EXPRESSION BY WESTERN BLOT AND APOPTOSIS RATES BY FLOW CYTOMETRY USING ANNEXIN V/PROPIDIUM IODIDE DOUBLE STAINING. RESULTS: IN K562 CELLS, TMS1 WAS COMPLETELY METHYLATED AND BOTH TMS1 MRNA AND PROTEIN SHOWED A LOW EXPRESSION, BUT 2 MUMOL/L AS2O3 COULD SIGNIFICANTLY RESTORE THE EXPRESSION OF THE TMS1 GENE BOTH AT MRNA AND PROTEIN LEVEL (P < 0.01) BY FULLY REVERSING DNA METHYLATION. AS2O3 DECREASED MRNA AND PROTEIN EXPRESSION OF DNMT1 (P < 0.05) IN A DOSE-DEPENDENT MANNER. FLOW CYTOMETRY SHOWED THAT IN THE EXPERIMENTAL GROUP (2 MUMOL/L AS2O3), CELL APOPTOSIS WAS SIGNIFICANTLY INCREASED COMPARED WITH THE CONTROL GROUP (NO AS2O3; P < 0.05). IN THE EXPERIMENTAL GROUP, WESTERN BLOT SHOWED THAT THE EXPRESSION OF THE ANTI-APOPTOTIC PROTEIN BCL-2 WAS SIGNIFICANTLY DECREASED; HOWEVER, THE PROAPOPTOTIC PROTEIN BAX WAS MARKEDLY INCREASED AND THE BCL-2/BAX RATIO WAS MARKEDLY REDUCED (P < 0.01). CONCLUSIONS: AS2O3 COULD RESTORE THE EXPRESSION OF TMS1 BY INHIBITING DNMT TO REVERSE THE HYPERMETHYLATION AND INDUCED APOPTOSIS OF K562 CELLS BY DOWNREGULATION OF BCL-2/BAX EXPRESSION. 2015 3 6688 32 VALPROATE SYNERGIZES WITH PURINE NUCLEOSIDE ANALOGUES TO INDUCE APOPTOSIS OF B-CHRONIC LYMPHOCYTIC LEUKAEMIA CELLS. RESISTANCE TO CHEMOTHERAPY AND DRUG TOXICITY ARE TWO MAJOR CONCERNS OF CHRONIC LYMPHOCYTIC LEUKAEMIA (B-CLL) TREATMENT BY PURINE NUCLEOSIDE ANALOGUES (PNA, I.E. FLUDARABINE AND CLADRIBINE). WE HYPOTHESIZED THAT TARGETING EPIGENETIC CHANGES MIGHT ADDRESS THESE ISSUES AND EVALUATED THE EFFECT OF THE HISTONE DEACETYLASE INHIBITOR VALPROATE (VPA) AT A CLINICALLY RELEVANT CONCENTRATION. VPA ACTED IN A HIGHLY SYNERGISTIC/ADDITIVE MANNER WITH FLUDARABINE AND CLADRIBINE TO INDUCE APOPTOSIS OF B-CLL CELLS. IMPORTANTLY, VPA ALSO RESTORED SENSITIVITY TO FLUDARABINE IN B CELLS FROM POOR PROGNOSIS CLL PATIENTS WHO BECAME RESISTANT TO CHEMOTHERAPY. MECHANISM OF APOPTOSIS INDUCED BY VPA ALONE OR COMBINED WITH FLUDARABINE OR TO CLADRIBINE WAS CASPASE-DEPENDENT AND INVOLVED THE EXTRINSIC PATHWAY. VPA, BUT NEITHER FLUDARABINE NOR CLADRIBINE, ENHANCED THE PRODUCTION OF REACTIVE OXYGEN SPECIES (ROS) AND INHIBITION OF ROS WITH N-ACETYLCYSTEINE DECREASES APOPTOSIS OF CLL CELLS. VPA STIMULATES HYPERPHOSPHORYLATION OF P42/P44 ERK, CYTOCHROME C RELEASE AND OVEREXPRESSION OF BAX AND FAS. TOGETHER, OUR DATA INDICATE THAT VPA MAY AMELIORATE THE OUTCOME OF PNA-BASED THERAPEUTIC PROTOCOLS AND PROVIDE A POTENTIAL ALTERNATIVE TREATMENT IN BOTH THE RELAPSED AND FRONT-LINE RESISTANT PATIENTS AND IN PATIENTS WITH HIGH RISK FEATURES. 2009 4 3828 38 INVOLVEMENT OF B-CELL CLL/LYMPHOMA 2 PROMOTER METHYLATION IN CIGARETTE SMOKE EXTRACT-INDUCED EMPHYSEMA. ABNORMAL APOPTOTIC EVENTS PLAY AN IMPORTANT ROLE IN THE PATHOGENESIS OF EMPHYSEMA. THE B-CELL CLL/LYMPHOMA 2 (BCL-2) FAMILY PROTEINS ARE ESSENTIAL AND CRITICAL REGULATORS OF APOPTOSIS. WE DETERMINED WHETHER THE ANTI-APOPTOTIC BCL-2 PLAY A ROLE IN THE CIGARETTE SMOKE EXTRACT (CSE)-INDUCED EMPHYSEMA. FURTHERMORE, GIVEN THE INVOLVEMENT OF EPIGENETICS IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE, WE HYPOTHESIZED THAT THE DEREGULATION OF BCL-2 MIGHT BE CAUSED BY GENE METHYLATION. THE EMPHYSEMA IN BALB/C MICE WAS ESTABLISHED BY INTRAPERITONEALLY INJECTION OF CSE. 5-AZA-2'-DEOXYCYTIDINE (AZA; A DEMETHYLATION REAGENT) AND PHOSPHATE-BUFFERED SALINE WERE ALSO ADMINISTERED INTRAPERITONEALLY AS CSE. TUNEL ASSAY WAS USED TO ASSESS APOPTOTIC INDEX OF PULMONARY CELLS. THE METHYLATION STATUS OF CPG DINUCLEOTIDES WITHIN THE BCL-2 PROMOTER WAS OBSERVED IN ALL GROUPS BY BISULFITE SEQUENCING PCR. PULMONARY EXPRESSION OF BCL-2, BAX, AND CYTOCHROME C WERE MEASURED AFTER FOUR WEEKS OF TREATMENT. THE APOPTOTIC INDEX OF PULMONARY CELLS IN CSE INJECTION GROUP WAS MUCH HIGHER THAN CONTROL ((25.88 +/- 7.55)% VS (6.28 +/- 2.96)%). COMPARED TO CONTROL MICE, DECREASED EXPRESSION OF BCL-2 AND HIGH METHYLATION OF BCL-2 PROMOTER WAS OBSERVED IN CSE INJECTED MICE (0.88 +/- 0.08 VS 0.49 +/- 0.11, (3.82 +/- 1.34)% VS (35.68 +/- 5.99)%, P < 0.01).CSE TREATMENT INDUCED LUNG CELL APOPTOSIS AND DECREASED LUNG FUNCTION. AZA TREATMENT INCREASED BCL-2 EXPRESSION WITH BCL-2 PROMOTER DEMETHYLATION. AZA ALSO ALLEVIATED THE LUNG CELL APOPTOSIS AND FUNCTION FAILURE CAUSED BY CSE TREATMENT. THE DECREASED EXPRESSION OF ANTI-APOPTOTIC BCL-2 MIGHT ACCOUNT FOR THE INCREASED APOPTOSIS IN CSE INDUCED-EMPHYSEMA. APPARENTLY, EPIGENETIC ALTERNATION PLAYED A ROLE IN THIS DEREGULATION OF BCL-2 EXPRESSION, AND IT MIGHT SUPPORT THE INVOLVEMENT OF EPIGENETIC EVENTS IN THE PATHOGENESIS OF EMPHYSEMA. 2016 5 6425 27 THE TRANSCRIPTION FACTOR REST UP-REGULATES TYROSINE HYDROXYLASE AND ANTIAPOPTOTIC GENES AND PROTECTS DOPAMINERGIC NEURONS AGAINST MANGANESE TOXICITY. DOPAMINERGIC FUNCTIONS ARE IMPORTANT FOR VARIOUS BIOLOGICAL ACTIVITIES, AND THEIR IMPAIRMENT LEADS TO NEURODEGENERATION, A HALLMARK OF PARKINSON'S DISEASE (PD). CHRONIC MANGANESE (MN) EXPOSURE CAUSES THE NEUROLOGICAL DISORDER MANGANISM, PRESENTING SYMPTOMS SIMILAR TO THOSE OF PD. EMERGING EVIDENCE HAS LINKED THE TRANSCRIPTION FACTOR RE1-SILENCING TRANSCRIPTION FACTOR (REST) TO PD AND ALSO ALZHEIMER'S DISEASE. BUT REST'S ROLE IN DOPAMINERGIC NEURONS IS UNCLEAR. HERE, WE INVESTIGATED WHETHER REST PROTECTS DOPAMINERGIC NEURONS AGAINST MN-INDUCED TOXICITY AND ENHANCES EXPRESSION OF THE DOPAMINE-SYNTHESIZING ENZYME TYROSINE HYDROXYLASE (TH). WE REPORT THAT REST BINDS TO RE1 CONSENSUS SITES IN THE TH GENE PROMOTER, STIMULATES TH TRANSCRIPTION, AND INCREASES TH MRNA AND PROTEIN LEVELS IN DOPAMINERGIC CELLS. REST BINDING TO THE TH PROMOTER RECRUITED THE EPIGENETIC MODIFIER CAMP-RESPONSE ELEMENT-BINDING PROTEIN-BINDING PROTEIN/P300 AND THEREBY UP-REGULATED TH EXPRESSION. REST RELIEVED MN-INDUCED REPRESSION OF TH PROMOTER ACTIVITY, MRNA, AND PROTEIN LEVELS AND ALSO REDUCED MN-INDUCED OXIDATIVE STRESS, INFLAMMATION, AND APOPTOSIS IN DOPAMINERGIC NEURONS. REST REDUCED MN-INDUCED PROINFLAMMATORY CYTOKINES, INCLUDING TUMOR NECROSIS FACTOR ALPHA, INTERLEUKIN 1BETA (IL-1BETA), IL-6, AND INTERFERON GAMMA. MOREOVER, REST INHIBITED THE MN-INDUCED PROAPOPTOTIC PROTEINS BCL-2-ASSOCIATED X PROTEIN (BAX) AND DEATH-ASSOCIATED PROTEIN 6 (DAXX) AND ATTENUATED AN MN-INDUCED DECREASE IN THE ANTIAPOPTOTIC PROTEINS BCL-2 AND BCL-XL. REST ALSO ENHANCED THE EXPRESSION OF ANTIOXIDANT PROTEINS, INCLUDING CATALASE, NF-E2-RELATED FACTOR 2 (NRF2), AND HEME OXYGENASE 1 (HO-1). OUR FINDINGS INDICATE THAT REST ACTIVATES TH EXPRESSION AND THEREBY PROTECTS NEURONS AGAINST MN-INDUCED TOXICITY AND NEUROLOGICAL DISORDERS ASSOCIATED WITH DOPAMINERGIC NEURODEGENERATION. 2020 6 5703 44 SINGLE-CELL MULTIOMICS REVEAL THE SCALE OF MULTILAYERED ADAPTATIONS ENABLING CLL RELAPSE DURING VENETOCLAX THERAPY. VENETOCLAX (VEN) INHIBITS THE PROSURVIVAL PROTEIN BCL2 TO INDUCE APOPTOSIS AND IS A STANDARD THERAPY FOR CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), DELIVERING HIGH COMPLETE REMISSION RATES AND PROLONGED PROGRESSION-FREE SURVIVAL IN RELAPSED CLL BUT WITH EVENTUAL LOSS OF EFFICACY. A SPECTRUM OF SUBCLONAL GENETIC CHANGES ASSOCIATED WITH VEN RESISTANCE HAS NOW BEEN DESCRIBED. TO FULLY UNDERSTAND CLINICAL RESISTANCE TO VEN, WE COMBINED SINGLE-CELL SHORT- AND LONG-READ RNA-SEQUENCING TO REVEAL THE PREVIOUSLY UNAPPRECIATED SCALE OF GENETIC AND EPIGENETIC CHANGES UNDERPINNING ACQUIRED VEN RESISTANCE. THESE APPEAR TO BE MULTILAYERED. ONE LAYER COMPRISES CHANGES IN THE BCL2 FAMILY OF APOPTOSIS REGULATORS, ESPECIALLY THE PROSURVIVAL FAMILY MEMBERS. THIS INCLUDES PREVIOUSLY DESCRIBED MUTATIONS IN BCL2 AND AMPLIFICATION OF THE MCL1 GENE BUT IS HETEROGENEOUS ACROSS AND WITHIN INDIVIDUAL PATIENT LEUKEMIAS. CHANGES IN THE PROAPOPTOTIC GENES ARE NOTABLY UNCOMMON, EXCEPT FOR SINGLE CASES WITH SUBCLONAL LOSSES OF BAX OR NOXA. MUCH MORE PROMINENT WAS UNIVERSAL MCL1 GENE UPREGULATION. THIS WAS DRIVEN BY AN OVERLYING LAYER OF EMERGENT NF-KAPPAB (NUCLEAR FACTOR KAPPA B) ACTIVATION, WHICH PERSISTED IN CIRCULATING CELLS DURING VEN THERAPY. WE DISCOVERED THAT MCL1 COULD BE A DIRECT TRANSCRIPTIONAL TARGET OF NF-KAPPAB. BOTH THE SWITCH TO ALTERNATIVE PROSURVIVAL FACTORS AND NF-KAPPAB ACTIVATION LARGELY DISSIPATE FOLLOWING VEN DISCONTINUATION. OUR STUDIES REVEAL THE EXTENT OF PLASTICITY OF CLL CELLS IN THEIR ABILITY TO EVADE VEN-INDUCED APOPTOSIS. IMPORTANTLY, THESE FINDINGS PINPOINT NEW APPROACHES TO CIRCUMVENT VEN RESISTANCE AND PROVIDE A SPECIFIC BIOLOGICAL JUSTIFICATION FOR THE STRATEGY OF VEN DISCONTINUATION ONCE A MAXIMAL RESPONSE IS ACHIEVED RATHER THAN MAINTAINING LONG-TERM SELECTIVE PRESSURE WITH THE DRUG. 2022 7 2081 35 EPIGENETIC DOWN-REGULATION OF BIM EXPRESSION IS ASSOCIATED WITH REDUCED OPTIMAL RESPONSES TO IMATINIB TREATMENT IN CHRONIC MYELOID LEUKAEMIA. BACKGROUND: EXPRESSION OF THE PRO-APOPTOTIC BCL-2-INTERACTING MEDIATOR (BIM) HAS RECENTLY BEEN IMPLICATED IN IMATINIB-INDUCED APOPTOSIS OF BCR-ABL1(+) CELLS. HOWEVER, THE MECHANISMS INVOLVED IN THE REGULATION OF BIM IN CML AND ITS ROLE IN THE CLINICAL SETTING HAVE NOT BEEN ESTABLISHED. DESIGN AND METHODS: WE ANALYSED THE MRNA EXPRESSION OF BIM IN 100 NEWLY DIAGNOSED PATIENTS WITH CML IN CHRONIC PHASE BY Q-RT-PCR AND THE PROTEIN LEVELS BY WESTERN BLOT ANALYSIS. METHYLATION STATUS WAS ANALYSED BY BISULPHITE GENOMIC SEQUENCING AND MSP. CML CELL LINES WERE TREATED WITH IMATINIB AND 5-AZA-2'-DEOXYCYTIDINE, AND WERE TRANSFECTED WITH TWO DIFFERENT SIRNAS AGAINST BIM AND CELL PROLIFERATION AND APOPTOSIS WERE ANALYSED. RESULTS: WE DEMONSTRATED THAT DOWN-REGULATION OF BIM EXPRESSION WAS PRESENT IN 36% OF THE PATIENTS AND WAS SIGNIFICANTLY ASSOCIATED WITH A LACK OF OPTIMAL RESPONSE TO IMATINIB AS INDICATED BY THE DECREASE IN CYTOGENETIC AND MOLECULAR RESPONSES AT 6, 12 AND 18 MONTHS IN COMPARISON WITH PATIENTS WITH NORMAL BIM EXPRESSION (P<0.05). EXPRESSION OF BIM WAS MEDIATED BY PROMOTER HYPERMETHYLATION AS DEMONSTRATED BY RESTORATION OF BIM EXPRESSION AFTER TREATMENT OF CML CELLS WITH 5-AZA-2'-DEOXYCYTIDINE. USING CML CELL LINES WITH LOW AND NORMAL EXPRESSION OF BIM WE FURTHER DEMONSTRATED THAT THE EXPRESSION OF BIM IS REQUIRED FOR IMATINIB-INDUCED CML APOPTOSIS. CONCLUSION: OUR DATA INDICATE THAT DOWN-REGULATION OF BIM IS EPIGENETICALLY CONTROLLED BY METHYLATION IN A PERCENTAGE OF CML PATIENTS AND HAS AN UNFAVOURABLE PROGNOSTIC IMPACT, AND THAT THE COMBINATION OF IMATINIB WITH A DE-METHYLATING AGENT MAY RESULT IN IMPROVED RESPONSES IN PATIENTS WITH DECREASED EXPRESSION OF BIM. 2009 8 6402 28 THE ROLES OF EPIGENETIC MODIFICATIONS OF PROAPOPTOTIC BID AND BIM GENES IN IMATINIB-RESISTANT CHRONIC MYELOID LEUKEMIA CELLS. IN CHRONIC MYELOID LEUKEMIA (CML), EPIGENETIC MODIFICATIONS SUCH AS PROMOTER HYPERMETHYLATION AND INACTIVE HISTONE MODIFICATION ARE KNOWN MECHANISMS OF DRUG RESISTANCE. IN OUR STUDY, WE INVESTIGATED THE ROLES OF PROMOTER HYPERMETHYLATION OF BIM AND BID GENES AND H3K27ME3 HISTONE MODIFICATION ON IMATINIB RESISTANCE. WE DETECTED HIGHER EXPRESSION LEVELS OF BIM AND BID GENES AND LOWER EXPRESSION LEVELS OF EZH2, EED2, SIRT1, AND SUZ12 GENES IN IMATINIB-RESISTANT K562/IMA-3 CELLS COMPARED TO IMATINIB-NON-RESISTANT K562 CELLS. WHILE WE DETERMINED THE EZH2 AND DNMT ENZYMES AS BOUNDED TO THE PROMOTER OF THE BIM GENE, WE DID NOT DETECT HYPERMETHYLATION OF THIS PROMOTER. WE ALSO FOUND THE H3K27ME3 HISTONE MODIFICATION PROMOTER OF BIM AND BID GENES IN BOTH CELL LINES. IN CONCLUSION, OUR RESULTS SUPPORT THE NOTION THAT DNA PROMOTER METHYLATION MAY BE FORMED INDEPENDENTLY FROM EZH2-H3K27ME3 AND PRO-APOPTOTIC BIM AND BID GENES ARE NOT METHYLLATED IN THE IMATINIB RESISTANCE OF CML CELLS. 2013 9 5690 34 SILENCING OF FEM1CR3 GENE EXPRESSION IN THE DBA/2J MOUSE PRECEDES RETINAL GANGLION CELL DEATH AND IS ASSOCIATED WITH HISTONE DEACETYLASE ACTIVITY. PURPOSE: DOWNREGULATION OF NORMAL GENE EXPRESSION IN DYING RETINAL GANGLION CELLS HAS BEEN DOCUMENTED IN BOTH ACUTE AND CHRONIC MODELS OF OPTIC NERVE DISEASE. THE AUTHORS EXAMINED THE MECHANISM AND TIMING OF THIS PHENOMENON IN DBA/2J MICE, USING GENETICALLY MODIFIED SUBSTRAINS OF THIS INBRED LINE. METHODS: DBA/2J MICE, DOUBLY CONGENIC FOR THE BAX MUTANT ALLELE AND THE GANGLION CELL REPORTER GENE FEM1C(ROSA3) (R3), WERE EVALUATED TO ELUCIDATE THE TIMING OF LOSS OF NORMAL GENE EXPRESSION DURING THE APOPTOTIC PROCESS. THE LOCALIZATION OF HISTONE DEACETYLASE 3 (HDAC3) AND NUCLEAR HISTONE H4 ACETYLATION WERE EXAMINED BY IMMUNOFLUORESCENCE IN DYING CELLS. THE ROLE OF HDACS IN GENE SILENCING DURING GLAUCOMA WAS INTERROGATED USING THE GLOBAL HDAC INHIBITOR TRICHOSTATIN A (TSA). RESULTS: SILENCING OF THE R3 ALLELE OCCURRED IN BAX(-/-) GANGLION CELLS, INDICATING THAT THIS PROCESS PRECEDED THE COMMITTED STEP OF THE INTRINSIC APOPTOTIC PATHWAY. WEEKLY TSA TREATMENT, BETWEEN THE AGES OF 6 AND 10 MONTHS, WAS ABLE TO ATTENUATE THE LOSS OF R3 EXPRESSION IN THE RETINA, BUT HAD NO EFFECT ON OPTIC NERVE DEGENERATION. DYING CELLS IN AGING DBA/2J MICE EXHIBITED NUCLEAR LOCALIZATION OF HDAC3 AND A DECREASE IN THE LEVEL OF H4 ACETYLATION. CONCLUSIONS: RETINAL GANGLION CELLS EXHIBIT A LOSS OF NORMAL GENE EXPRESSION AS AN EARLY (PRE-BAX INVOLVEMENT) PART OF THEIR APOPTOTIC PROGRAM DURING GLAUCOMATOUS DEGENERATION. THIS PROCESS CAN BE AMELIORATED, BUT NOT COMPLETELY BLOCKED, USING HDAC INHIBITORS. EPIGENETIC CHANGES TO ACTIVE CHROMATIN, SUCH AS DEACETYLATION, MAY BE MEDIATED BY HDAC3 IN DYING NEURONS. 2012 10 3175 33 H2AX PHOSPHORYLATION REGULATED BY P38 IS INVOLVED IN BIM EXPRESSION AND APOPTOSIS IN CHRONIC MYELOGENOUS LEUKEMIA CELLS INDUCED BY IMATINIB. INCREASING EVIDENCE SUGGESTS THAT HISTONE H2AX PLAYS A CRITICAL ROLE IN REGULATION OF TUMOR CELL APOPTOSIS AND ACTS AS A NOVEL HUMAN TUMOR SUPPRESSOR PROTEIN. HOWEVER, THE ACTION OF H2AX IN CHRONIC MYELOGENOUS LEUKEMIA (CML) CELLS IS UNKNOWN. THE DETAILED MECHANISM AND EPIGENETIC REGULATION BY H2AX REMAIN ELUSIVE IN CANCER CELLS. HERE, WE REPORT THAT H2AX WAS INVOLVED IN APOPTOSIS OF CML CELLS. OVEREXPRESSION OF H2AX INCREASED APOPTOTIC SENSITIVITY OF CML CELLS (K562) INDUCED BY IMATINIB. HOWEVER, OVEREXPRESSION OF SER139-MUTATED H2AX (BLOCKING PHOSPHORYLATION) DECREASED SENSITIVITY OF K562 CELLS TO APOPTOSIS. SIMILARLY, KNOCKDOWN OF H2AX MADE K562 CELLS RESISTANT TO APOPTOTIC INDUCTION. THESE RESULTS REVEALED THAT THE FUNCTION OF H2AX INVOLVED IN APOPTOSIS IS STRICTLY RELATED TO ITS PHOSPHORYLATION (SER139). OUR DATA FURTHER INDICATED THAT IMATINIB MAY STIMULATE MITOGEN-ACTIVATED PROTEIN KINASE (MAPK) FAMILY MEMBER P38, AND H2AX PHOSPHORYLATION FOLLOWED A SIMILAR TIME COURSE, SUGGESTING A PARALLEL RESPONSE. H2AX PHOSPHORYLATION CAN BE BLOCKED BY P38 SIRNA OR ITS INHIBITOR. THESE DATA DEMONSTRATED THAT H2AX PHOSPHORYLATION WAS REGULATED BY P38 MAPK PATHWAY IN K562 CELLS. HOWEVER, THE P38 MAPK DOWNSTREAM, MITOGEN- AND STRESS-ACTIVATED PROTEIN KINASE-1 AND -2, WHICH PHOSPHORYLATED HISTONE H3, WERE NOT REQUIRED FOR H2AX PHOSPHORYLATION DURING APOPTOSIS. FINALLY, WE PROVIDED EPIGENETIC EVIDENCE THAT H2AX PHOSPHORYLATION REGULATED APOPTOSIS-RELATED GENE BIM EXPRESSION. BLOCKING OF H2AX PHOSPHORYLATION INHIBITED BIM GENE EXPRESSION. TAKEN TOGETHER, THESE DATA DEMONSTRATED THAT H2AX PHOSPHORYLATION REGULATED BY P38 IS INVOLVED IN BIM EXPRESSION AND APOPTOSIS IN CML CELLS INDUCED BY IMATINIB. 2014 11 5917 42 TARGETING BCL-2 IN B-CELL MALIGNANCIES AND OVERCOMING THERAPEUTIC RESISTANCE. DEFECTS IN APOPTOSIS CAN PROMOTE TUMORIGENESIS AND IMPAIR RESPONSES OF MALIGNANT B CELLS TO CHEMOTHERAPEUTICS. MEMBERS OF THE B-CELL LEUKEMIA/LYMPHOMA-2 (BCL-2) FAMILY OF PROTEINS ARE KEY REGULATORS OF THE INTRINSIC, MITOCHONDRIAL APOPTOTIC PATHWAY. OVEREXPRESSION OF ANTIAPOPTOTIC BCL-2 FAMILY PROTEINS IS ASSOCIATED WITH TREATMENT RESISTANCE AND POOR PROGNOSIS. THUS, INHIBITION OF BCL-2 FAMILY PROTEINS IS A RATIONAL THERAPEUTIC OPTION FOR MALIGNANCIES THAT ARE DEPENDENT ON ANTIAPOPTOTIC BCL-2 FAMILY PROTEINS. VENETOCLAX (ABT-199, GDC-0199) IS A HIGHLY SELECTIVE BCL-2 INHIBITOR THAT REPRESENTS THE FIRST APPROVED AGENT OF THIS CLASS AND IS CURRENTLY WIDELY USED IN THE TREATMENT OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) AS WELL AS ACUTE MYELOID LEUKEMIA (AML). DESPITE IMPRESSIVE CLINICAL ACTIVITY, VENETOCLAX MONOTHERAPY FOR A PROLONGED DURATION CAN LEAD TO DRUG RESISTANCE OR LOSS OF DEPENDENCE ON THE TARGETED PROTEIN. IN THIS REVIEW, WE PROVIDE AN OVERVIEW OF THE MECHANISM OF ACTION OF BCL-2 INHIBITION AND THE ROLE OF THIS APPROACH IN THE CURRENT TREATMENT PARADIGM OF B-CELL MALIGNANCIES. WE SUMMARIZE THE DRIVERS OF DE NOVO AND ACQUIRED RESISTANCE TO VENETOCLAX THAT ARE CLOSELY ASSOCIATED WITH COMPLEX CLONAL SHIFTS, INTERPLAY OF EXPRESSION AND INTERACTIONS OF BCL-2 FAMILY MEMBERS, TRANSCRIPTIONAL REGULATORS, AND METABOLIC MODULATORS. WE ALSO EXAMINE HOW TUMORS INITIALLY RESISTANT TO VENETOCLAX BECOME RESPONSIVE TO IT FOLLOWING PRIOR THERAPIES. HERE, WE SUMMARIZE PRECLINICAL DATA PROVIDING A RATIONALE FOR EFFICACIOUS COMBINATION STRATEGIES OF VENETOCLAX TO OVERCOME THERAPEUTIC RESISTANCE BY A TARGETED APPROACH DIRECTED AGAINST ALTERNATIVE ANTIAPOPTOTIC BCL-2 FAMILY PROTEINS (MCL-1, BCL-XL), COMPENSATORY PROSURVIVAL PATHWAYS, EPIGENETIC MODIFIERS, AND DYSREGULATED CELLULAR METABOLISM/ENERGETICS FOR DURABLE CLINICAL REMISSIONS. 2020 12 4175 26 MELATONIN PROTECTS CHOLANGIOCYTES FROM OXIDATIVE STRESS-INDUCED PROAPOPTOTIC AND PROINFLAMMATORY STIMULI VIA MIR-132 AND MIR-34. BIOSYNTHESIS OF MELATONIN BY CHOLANGIOCYTES IS ESSENTIAL FOR MAINTAINING THE FUNCTION OF BILIARY EPITHELIUM. HOWEVER, THIS CYTOPROTECTIVE MECHANISM APPEARS TO BE IMPAIRED IN PRIMARY BILIARY CHOLANGITIS (PBC). MIR-132 HAS EMERGED AS A MEDIATOR OF INFLAMMATION IN CHRONIC LIVER DISEASES. THE EFFECT OF MELATONIN ON OXIDATIVE STRESS AND BILE ACID-INDUCED APOPTOSIS WAS ALSO EXAMINED IN CHOLANGIOCYES OVEREXPRESSING MIR506, AS A PBC-LIKE CELLULAR MODEL. IN PBC PATIENTS THE SERUM LEVELS OF MELATONIN WERE FOUND INCREASED IN COMPARISON TO HEALTHY CONTROLS. WHEREAS, IN CHOLANGIOCYTES WITHIN CIRRHOTIC PBC LIVERS THE MELATONIN BIOSYNTHETIC PATHWAY WAS SUBSTANTIALLY SUPPRESSED EVEN THOUGH THE EXPRESSIONS OF MELATONIN RATE-LIMITING ENZYME ARALKYLAMINE N-ACETYLTRANSFERASE (AANAT), AND CK-19 (MARKER OF CHOLANGIOCYTES) WERE ENHANCED. IN CHOLANGIOCYTES EXPOSED TO MITOCHONDRIAL OXIDATIVE STRESS MELATONIN DECREASED THE EXPRESSION OF PROAPOPTOTIC STIMULI (PTEN, BAX, MIR-34), WHICH WAS ACCOMPANIED BY THE INHIBITION OF A PIVOTAL MEDIATOR OF INFLAMMATORY RESPONSE NF-KAPPAB-P65 AND THE ACTIVATION OF ANTIAPOPTOTIC SIGNALING (MIR-132, BCL2). SIMILARLY, MELATONIN REDUCED BILE ACID-INDUCED PROAPOPTOTIC CASPASE 3 AND BIM LEVELS. IN SUMMARY, THE INSUFFICIENT HEPATIC EXPRESSION OF MELATONIN IN PBC PATIENTS MAY PREDISPOSE CHOLANGIOCYTES TO OXIDATIVE STRESS-RELATED DAMAGE. MELATONIN, VIA EPIGENETIC MODULATION, WAS ABLE TO SUPPRESS NF-KAPPAB SIGNALING ACTIVATION AND PROTECT AGAINST BILIARY CELLS APOPTOTIC SIGNALING. 2020 13 2326 39 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 14 2440 33 EPIGENETIC SILENCING OF TUMOR SUPPRESSOR LONG NON-CODING RNA BM742401 IN CHRONIC LYMPHOCYTIC LEUKEMIA. BM742401 IS A TUMOR SUPPRESSOR LNCRNA DOWNREGULATED IN GASTRIC CANCER. AS THE PROMOTER REGION AND THE ENTIRE TRANSCRIPT ARE EMBEDDED IN A CPG ISLAND, WE POSTULATED THAT BM742401 IS A TUMOR SUPPRESSOR LNCRNA INACTIVATED BY DNA METHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). THE PROMOTER OF BM742401 WAS UNMETHYLATED IN NORMAL CONTROLS INCLUDING THREE EACH OF NORMAL BONE MARROW, PERIPHERAL BLOOD BUFFY COATS, AND CD19-SORTED PERIPHERAL B-CELLS, BUT METHYLATED IN FOUR (57.1%) CLL CELL LINES. METHYLATION OF BM742401 CORRELATED INVERSELY WITH EXPRESSION. IN THE COMPLETELY METHYLATED WAC3CD5+ CLL CELLS, 5-AZA-2'-DEOXYCYTIDINE TREATMENT LED TO PROMOTER DEMETHYLATION AND RE-EXPRESSION OF BM742401 TRANSCRIPT. FUNCTIONALLY, STABLE OVEREXPRESSION OF BM742401 RESULTED IN INHIBITION OF CELLULAR PROLIFERATION AND ENHANCED APOPTOSIS THROUGH CASPASE-9-DEPENDENT INTRINSIC BUT NOT CASPASE-8-DEPENDENT EXTRINSIC APOPTOSIS PATHWAY, SUGGESTING A TUMOR SUPPRESSOR ROLE OF BM742401 IN CLL. IN PRIMARY CLL SAMPLES, METHYLATION OF BM742401 WAS DETECTED IN 43/98 (43.9%) OF PATIENTS. MOREOVER, AMONG CLL PATIENTS WITH STANDARD-RISK CYTOGENETIC ABERRATIONS, METHYLATION OF BM742401 CORRELATED WITH ADVANCED RAI STAGE (>/= STAGE 2)(P = 0.002). FURTHERMORE, BM742401 METHYLATION WAS ASSOCIATED WITH MIR-129-2 METHYLATION (P = 0.05). BM742401 IS A TUMOR SUPPRESSOR LNCRNA FREQUENTLY METHYLATED IN CLL. THE MECHANISM OF BM742401 AS A TUMOR SUPPRESSOR WARRANTS FURTHER STUDIES. 2016 15 5459 30 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 16 4601 35 NDRG2 MRNA LEVELS AND MIR-28-5P AND MIR-650 ACTIVITY IN CHRONIC LYMPHOCYTIC LEUKEMIA. BACKGROUND: NDRG2 IS IDENTIFIED AS A TUMOR SUPPRESSOR GENE IN MANY TUMORS, AND FUNCTIONS IN CELL PROLIFERATION, DIFFERENTIATION AND APOPTOSIS. RECENT DATA INDICATE THAT NDRG2 EXPRESSION IS UP-REGULATED BY TP53. MOREOVER, PROPOSED MECHANISMS OF NDRG2 INACTIVATION INCLUDE EPIGENETIC SILENCING OF THE NDRG2 PROMOTER AND DOWN-REGULATION BY MICRORNAS (MIRNAS). HOWEVER, FEW STUDIES HAVE EVER BEEN DONE ON THE ROLE OF NDRG2 AND THE NDRG2-REGULATING MIRNAS INTERFERENCE IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). METHODS: NDRG2 AND MICRORNAS MRNA LEVELS IN CLL SUBJECTS WERE ASSESSED BY QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (QRT-PCR). THE DUAL-LUCIFERASE REPORTER ASSAY WAS PERFORMED TO DETERMINE NDRG2-RELATED MIRNAS. LOW EXPRESSION OF MATURE EXOGENOUS MIRNAS IN CLL CELLS WAS ESTABLISHED BY TRANSIENT TRANSFECTION. NDRG2 PROTEIN LEVELS IN CLL CELLS WERE DETECTED BY WESTERN BLOT. IN ADDITION, FLOW CYTOMETRY WAS CONDUCTED TO EXAMINE THE APOPTOSIS OF CLL CELLS. RESULTS: LOWER EXPRESSION OF NDRG2 WAS FOUND IN THE B-CELLS FROM 102 CLL PATIENTS COMPARED THE 40 NORMAL SUBJECTS (P < 0.001). PATIENTS WITH ADVANCED BINET STAGE (P = 0.001), HIGH LACTATE DEHYDROGENASE (LDH) LEVEL (P = 0.036), UN-MUTATED IMMUNOGLOBULIN HEAVY CHAIN VARIABLE REGION GENE (IGHV) (P = 0.004) AND THOSE WITH P53 ABERRATIONS (P < 0.001) HAD A MARKEDLY LOWER LEVELS OF NDRG2 MRNA. THIS DECREASE WAS ASSOCIATED WITH BRIEFER TIME-TO-TREATMENT (P = 0.001) AND POORER SURVIVAL (P < 0.001). HIGH EXPRESSION OF MIR-28-5P AND MIR-650 WAS ASSOCIATED WITH BINET B/C STAGE (P = 0.044) AND IGHV UN-MUTATED (P = 0.011), AS WELL AS BINET B/C STAGE (P = 0.013) AND P53 ABERRATIONS (P = 0.037), RESPECTIVELY. INHIBITION OF MIR-28-5P OR MIR-650 COULD INDUCE MORE APOPTOSIS IN CLL CELLS WITH GERMLINE TP53. CONCLUSIONS: NDRG2 MRNA LEVELS MIGHT BE A USEFUL PROGNOSTIC VARIABLE FOR PATIENTS OF CLL AND UP-REGULATING NDRG2 TRANSCRIPTION MAY BE A THERAPY APPROACH IN CLL WITHOUT P53 ABERRATIONS. 2018 17 5229 35 PRO-APOPTOTIC TP53 HOMOLOG TAP63 IS REPRESSED VIA EPIGENETIC SILENCING AND B-CELL RECEPTOR SIGNALLING IN CHRONIC LYMPHOCYTIC LEUKAEMIA. CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) IS AN ACCUMULATIVE DISORDER MARKED BY DEFICIENT APOPTOSIS. THE TP53 HOMOLOG TAP63 PROMOTES APOPTOSIS AND CHEMOSENSITIVITY IN SOLID TUMOURS AND ITS DEREGULATION MAY CONTRIBUTE TO CLL CELL SURVIVAL. WE FOUND THAT TAP63ALPHA WAS THE MOST PREVALENT TP63 ISOFORM IN CLL. COMPARED TO HEALTHY B CELLS, TAP63 MRNA WAS REPRESSED IN 55.7% OF CLL SAMPLES. TP63 PROMOTER METHYLATION WAS HIGH IN CLL AND INVERSELY CORRELATED WITH TP63 PROTEIN EXPRESSION IN B-CELL LYMPHOMA CELL LINES. SIRNA-MEDIATED KNOCKDOWN OF TP63 RESULTED IN PARTIAL PROTECTION FROM SPONTANEOUS APOPTOSIS ACCOMPANIED BY REDUCTIONS IN PMAIP1 (NOXA), BBC3 (PUMA), AND BAX MRNA IN CLL CELLS AND INCREASED PROLIFERATION OF RAJI LYMPHOMA CELLS. TAP63 MRNA LEVELS WERE HIGHER IN CLL WITH UNMUTATED IGHV. B-CELL RECEPTOR (BCR) ENGAGEMENT LED TO REPRESSION OF TP63 MRNA EXPRESSION IN MALIGNANT B CELLS, WHILE PHARMACOLOGICAL INHIBITION OF BCR SIGNALLING PREVENTED TP63 DOWNREGULATION. MIR21, KNOWN TO TARGET TAP63, CORRELATED INVERSELY WITH TAP63 EXPRESSION IN CLL, AND BCR-MEDIATED DOWNREGULATION OF TP63 WAS ACCOMPANIED BY MIR21 UPREGULATION IN MOST CLL SAMPLES. OUR DATA ILLUSTRATE THE PRO-APOPTOTIC FUNCTION OF TP63, PROVIDE INSIGHTS INTO THE MECHANISMS OF BCR-TARGETING AGENTS, AND ESTABLISH A RATIONALE FOR DESIGNING NOVEL APPROACHES TO INDUCE TP63 IN CLL AND B-CELL LYMPHOMA. 2013 18 5479 25 RESVERATROL ATTENUATES CIGARETTE SMOKE EXTRACT INDUCED CELLULAR SENESCENCE IN HUMAN AIRWAY EPITHELIAL CELLS BY REGULATING THE MIR-34A/SIRT1/NF-KAPPAB PATHWAY. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS CHARACTERIZED BY ACCELERATED LUNG AGING. SMOKING IS THE CRITICAL RISK FACTOR FOR COPD. CELLULAR SENESCENCE OF AIRWAY EPITHELIAL CELLS IS THE CYTOLOGICAL BASIS OF ACCELERATED LUNG AGING IN COPD, AND THE REGULATION OF MICRORNAS (MIRNAS) IS THE CENTRAL EPIGENETIC MECHANISM OF CELLULAR SENESCENCE. RESVERATROL (RES) IS A POLYPHENOL WITH ANTI-AGING PROPERTIES. THIS STUDY INVESTIGATED WHETHER RES ATTENUATES CIGARETTE SMOKE EXTRACT (CSE)-INDUCED CELLULAR SENESCENCE IN HUMAN AIRWAY EPITHELIAL CELLS (BEAS-2B) THROUGH THE MIR-34A/SIRT1/NUCLEAR FACTOR-KAPPAB (NF-KAPPAB) PATHWAY. BEAS-2B CELLS WERE TREATED WITH RES, CSE AND TRANSFECTED WITH MIR-34A-5P MIMICS. CELLULAR SENESCENCE WAS EVALUATED BY SENESCENCE -RELATED BETA-GALACTOSIDASE (SA-BETA-GAL) STAINING AND EXPRESSION OF SENESCENCE-RELATED GENES (P16, P21, AND P53). THE EXPRESSIONS OF MIR-34A-5P, SIRT1, AND NF-KAPPAB P65 WERE EXAMINED USING QUANTITATIVE REAL TIME POLYMERASE CHAIN REACTION AND WESTERN BLOTTING. THE SENESCENCE-ASSOCIATED SECRETORY PHENOTYPE (SASP) CYTOKINES (IL-1BETA, IL-6, IL-8, TNF-ALPHA) WERE ASSESSED BY ENZYME-LINKED IMMUNOSORBENT ASSAY. THE BINDING BETWEEN MIR-34A-5P AND SIRT1 WAS CONFIRMED BY DUAL-LUCIFERASE REPORTER ASSAY. THE RESULTS SHOWED THAT CSE DOSE-DEPENDENTLY DECREASED CELL VIABILITY AND ELEVATED CELLULAR SENESCENCE, CHARACTERIZED BY INCREASED SA-BETA-GAL STAINING AND SENESCENCE-RELATED GENE EXPRESSIONS (P16, P21, AND P53). FURTHER, CSE DOSE-DEPENDENTLY INCREASED THE EXPRESSION OF MIR-34A-5P AND SASP CYTOKINES (IL-1BETA, IL-6, IL-8, TNF-ALPHA) IN BEAS-2B CELLS. PRETREATMENT WITH RES INHIBITED CSE-INDUCED CELLULAR SENESCENCE AND SECRETION OF SASP CYTOKINES (IL-1BETA, IL-6, IL-8, TNF-ALPHA) IN A DOSE-DEPENDENT MANNER. MOREOVER, RES REVERSED THE CSE-INDUCED DOWN-REGULATION OF SIRT1 AND UP-REGULATION OF MIR-34A-5P AND NF-KAPPAB P65. SIRT1 IS A TARGET OF MIR-34A-5P. OVEREXPRESSION OF MIR-34A-5P VIA TRANSFECTION WITH MIR-34A-5P MIMIC IN BEAS-2B CELLS ATTENUATED THE INHIBITORY EFFECT OF RES ON CELLULAR SENESCENCE, ACCOMPANIED BY REVERSING THE EXPRESSION OF SIRT1 AND NF-KAPPAB P65. IN CONCLUSION, RES ATTENUATED CSE-INDUCED CELLULAR SENESCENCE IN BEAS-2B CELLS BY REGULATING THE MIR-34A/SIRT1/NF-KAPPAB PATHWAY, WHICH MAY PROVIDE A NEW APPROACH FOR COPD TREATMENT. 2022 19 3725 41 INHIBITION OF GLYCOGEN SYNTHASE KINASE-3 ACTIVITY LEADS TO EPIGENETIC SILENCING OF NUCLEAR FACTOR KAPPAB TARGET GENES AND INDUCTION OF APOPTOSIS IN CHRONIC LYMPHOCYTIC LEUKEMIA B CELLS. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS COMMONLY DEFINED AS A DISEASE OF FAILED APOPTOSIS OF B CELLS AND REMAINS AN INCURABLE DISEASE. THE MECHANISM OF RESISTANCE TO APOPTOSIS IN CLL IS COMPLEX AND INFLUENCED BY NUMEROUS FACTORS, INCLUDING NUCLEAR FACTOR KAPPAB (NFKAPPAB)-MEDIATED EXPRESSION OF ANTIAPOPTOTIC MOLECULES. RECENT EVIDENCE INDICATES THAT GLYCOGEN SYNTHASE KINASE-3BETA (GSK-3BETA) POSITIVELY REGULATES NFKAPPAB-MEDIATED GENE TRANSCRIPTION AND CELL SURVIVAL. USING MALIGNANT B CELLS COLLECTED FROM PATIENTS WITH CLL, WE FIND THAT BOTH GSK-3BETA AND NFKAPPAB ACCUMULATE IN THE NUCLEUS OF CLL B CELLS, AND PHARMACOLOGIC INHIBITION OF GSK-3 RESULTS IN DECREASED EXPRESSION OF TWO NFKAPPAB TARGET GENES BCL-2 AND XIAP AND A SUBSEQUENT INCREASE IN CLL B-CELL APOPTOSIS EX VIVO. FURTHERMORE, WE OBSERVED THAT INHIBITION OF GSK-3 LEADS TO A DECREASE IN NFKAPPAB-MEDIATED GENE TRANSCRIPTION BUT DOES NOT AFFECT THE NUCLEAR ACCUMULATION OF NFKAPPAB IN CLL B CELLS. LAST, USING CHROMATIN IMMUNOPRECIPITATION, WE SHOW THAT GSK-3 INHIBITION ABROGATES NFKAPPAB BINDING TO ITS TARGET GENE PROMOTERS (XIAP, BCL-2), IN PART THROUGH EPIGENETIC MODIFICATION OF HISTONES. OUR RESULTS ESTABLISH THAT INHIBITION OF GSK-3 ABROGATES NFKAPPAB BINDING TO ITS TARGET GENE PROMOTERS THROUGH AN EPIGENETIC MECHANISM, ENHANCES APOPTOSIS IN CLL B CELLS EX VIVO AND IDENTIFIES GSK-3 AS A POTENTIAL THERAPEUTIC TARGET IN THE TREATMENT OF CLL. 2007 20 1287 31 DECITABINE-INDUCED APOPTOSIS IS DERIVED BY PUMA AND NOXA INDUCTION IN CHRONIC MYELOID LEUKEMIA CELL LINE AS WELL AS IN PBL AND IS POTENTIATED BY SAHA. RESTORATION OF CELLULAR APOPTOTIC PATHWAYS PLAYS A CRUCIAL ROLE IN CANCER THERAPY STRATEGIES. IN A BROAD SPECTRUM OF ANTICANCER DRUGS, EPIGENETIC EFFECTORS ARE IN THE CENTER OF INTEREST MOSTLY BECAUSE OF POTENTIAL REVERSIBILITY OF THEIR ACTION. METHYLATION STATUS OF THE CELLS IS INFLUENCED BY METHYLTRANSFERASE INHIBITOR 2-DEOXY-5'-AZACYTIDINE (DECITABINE, DAC), BUT HIGHER CONCENTRATIONS OF THIS AGENT CAUSE A DNA-DAMAGE. IN OUR STUDY, TUMOR SUPRESSOR P53-APOPTOTIC PATHWAY WAS ACTIVATED IN DECITABINE-INDUCED CELL DEATH. EXPRESSION OF P53-INDUCIBLE BH3-ONLY APOPTOTIC PROTEINS PUMA AND NOXA WAS ELEVATED AND LARGE ACTIVATION OF EXECUTIVE CASPASES WAS OBSERVED. THE EXTENT OF ACETYLATION IN THE CELL IS AFFECTED BY HISTONEDEACETYLASE INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA). COMBINATION OF SAHA WITH DECITABINE BROUGHT SYNERGISTIC EFFECT ON APOPTOSIS TRIGGERING IN CML-T1 CELL LINE, BUT APOPTOSIS AS WELL AS NECROSIS OCCURRED ALSO IN NORMAL PERIPHERAL BLOOD LYMPHOCYTES. THEREFORE, PROMISING POTENTIAL OF SUCH COMBINED THERAPY CALLS FOR MORE DETAILED INVESTIGATION OF UNWANTED EFFECTS IN NORMAL CELLS. 2011