1 3725 107 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 2 5871 39 SUSTAINED NF-KAPPAB ACTIVITY IN CHRONIC LYMPHOCYTIC LEUKEMIA IS INDEPENDENT OF GENETIC AND EPIGENETIC ALTERATIONS IN THE TNFAIP3 (A20) LOCUS. INAPPROPRIATE NUCLEAR FACTOR (NF) KAPPAB ACTIVITY IS ONE MAJOR HALLMARK OF B-CELL MALIGNANCIES AND CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). NFKAPPAB-DEPENDENT GENES ARE INVOLVED IN ANTIAPOPTOSIS, CELL PROLIFERATION AND METASTASIS AND ARE RESPONSIBLE FOR SURVIVAL AND PROLIFERATION OF TUMORS. HOWEVER, THE MECHANISMS OF NFKAPPAB ACTIVITY IN CLL STILL NEED TO BE ELUCIDATED. PREVIOUSLY, WE IDENTIFIED TRANSLOCATIONS IN A REGION ON CHROMOSOME 6Q THAT ENCODES TUMOR NECROSIS FACTOR ALPHA-INDUCED PROTEIN 3, WHICH IS A KEY PLAYER IN NEGATIVE FEEDBACK LOOP REGULATION OF NFKAPPAB. INACTIVATION OF THIS UBIQUITIN-EDITING ENZYME IS INVOLVED IN IMMUNOPATHOLOGIES AND IN TUMORIGENESIS. FREQUENT MUTATIONS IN THE A20 LOCUS--LEADING TO SUSTAINED NFKAPPAB ACTIVITY--COULD BE SHOWN TO PLAY A DOMINANT ROLE IN DEVELOPMENT OF DIFFERENT B-CELL MALIGNANCIES. TO CHECK IF A20 IS INVOLVED IN UPREGULATION OF NFKAPPAB ACTIVITY IN CLL, WE SEQUENCED EXONS 2-9 OF THE A20 GENE IN 55 CLL DNA SAMPLES. FURTHERMORE, WE DETERMINED THE METHYLATION STATUS OF THE PROMOTER REGION IN 63 CLL DNA SAMPLES AND COMPARED TO 10 CONTROL DNAS OF B CELLS FROM HEALTHY DONORS. CONTRARY TO REPORTS FROM OTHER B-CELL MALIGNANCIES, THE A20 REGION SHOWED NEITHER MUTATIONS NOR ABERRANT DNA METHYLATION. MOREOVER, ITS EXPRESSION COULD BE CONFIRMED BY IMMUNOBLOTTING AND SHOWING COMPARABLE RESULTS TO HEALTHY B CELLS. THESE RESULTS INDICATE THAT MALIGNANT DEVELOPMENT IN CLL DIFFERS FROM MOST OF OTHER B-CELL MALIGNANCIES, WHICH SHOW FREQUENT INACTIVATION OF A20. 2011 3 3415 34 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 4 5691 41 SILENCING OF HDAC6 AS A THERAPEUTIC TARGET IN CHRONIC LYMPHOCYTIC LEUKEMIA. ALTHOUGH THE TREATMENT PARADIGM FOR CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS RAPIDLY CHANGING, THE DISEASE REMAINS INCURABLE, EXCEPT WITH ALLOGENEIC BONE MARROW TRANSPLANTATION, AND RESISTANCE, RELAPSED DISEASE, AND PARTIAL RESPONSES PERSIST AS SIGNIFICANT CHALLENGES. RECENT STUDIES HAVE UNCOVERED ROLES FOR EPIGENETIC MODIFICATION IN THE REGULATION OF MECHANISMS CONTRIBUTING TO MALIGNANT PROGRESSION OF CLL B CELLS. HOWEVER, THE EXTENT TO WHICH EPIGENETIC MODIFIERS CAN BE TARGETED FOR THERAPEUTIC BENEFIT IN CLL PATIENTS REMAINS POORLY EXPLORED. WE REPORT FOR THE FIRST TIME THAT EXPRESSION OF EPIGENETIC MODIFIER HISTONE DEACETYLASE 6 (HDAC6) IS UPREGULATED IN CLL PATIENT SAMPLES, CELL LINES, AND EUTCL1 TRANSGENIC MOUSE MODELS COMPARED WITH HDAC6 IN NORMAL CONTROLS. GENETIC SILENCING OF HDAC6 CONFERRED SURVIVAL BENEFIT IN EUTCL1 MICE. ADMINISTRATION OF ISOFORM-SPECIFIC HDAC6 INHIBITOR ACY738 IN THE EUTCL1 AGING AND ADOPTIVE TRANSFER MODELS DETERRED PROLIFERATION OF CLL B CELLS, DELAYED DISEASE ONSET VIA DISRUPTION OF B-CELL RECEPTOR SIGNALING, AND SENSITIZED CLL B CELLS TO APOPTOSIS. FURTHERMORE, COADMINISTRATION OF ACY738 AND IBRUTINIB DISPLAYED SYNERGISTIC CELL KILL AGAINST CLL CELL LINES AND IMPROVED OVERALL SURVIVAL COMPARED WITH EITHER SINGLE AGENT IN VIVO. THESE RESULTS DEMONSTRATE FOR THE FIRST TIME THE THERAPEUTIC EFFICACY OF SELECTIVE HDAC6 INHIBITION IN PRECLINICAL CLL MODELS AND SUGGEST A RATIONALE FOR THE CLINICAL DEVELOPMENT OF HDAC6 INHIBITORS FOR CLL TREATMENT, EITHER ALONE OR IN COMBINATION WITH BRUTON TYROSINE KINASE INHIBITION. 2018 5 4728 30 NOTCH SIGNALING PROMOTES DISEASE INITIATION AND PROGRESSION IN MURINE CHRONIC LYMPHOCYTIC LEUKEMIA. NOTCH1 GAIN-OF-FUNCTION MUTATIONS ARE RECURRENT IN B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL), WHERE THEY ARE ASSOCIATED WITH ACCELERATED DISEASE PROGRESSION AND REFRACTORINESS TO CHEMOTHERAPY. THE SPECIFIC ROLE OF NOTCH1 IN THE DEVELOPMENT AND PROGRESSION OF THIS MALIGNANCY IS UNCLEAR. HERE, WE ASSESS THE IMPACT OF LOSS OF NOTCH SIGNALING AND PATHWAY HYPERACTIVATION IN AN IN VIVO MOUSE MODEL OF CLL (IGH.TEMU) THAT FAITHFULLY REPLICATES MANY FEATURES OF THE HUMAN PATHOLOGY. ABLATION OF CANONICAL NOTCH SIGNALING USING CONDITIONAL GENE INACTIVATION OF RBP-J IN IMMATURE HEMATOPOIETIC OR B-CELL PROGENITORS DELAYED CLL INDUCTION AND REDUCED INCIDENCE OF MICE DEVELOPING DISEASE. IN CONTRAST, FORCED EXPRESSION OF A DOMINANT ACTIVE FORM OF NOTCH RESULTED IN MORE ANIMALS DEVELOPING CLL WITH EARLY DISEASE ONSET. COMPARATIVE ANALYSIS OF GENE EXPRESSION AND EPIGENETIC FEATURES OF NOTCH GAIN-OF-FUNCTION AND CONTROL CLL CELLS REVEALED DIRECT AND INDIRECT REGULATION OF CELL CYCLE-ASSOCIATED GENES, WHICH LED TO INCREASED PROLIFERATION OF NOTCH GAIN-OF-FUNCTION CLL CELLS IN VIVO. THESE RESULTS DEMONSTRATE THAT NOTCH SIGNALING FACILITATES DISEASE INITIATION AND PROMOTES CLL CELL PROLIFERATION AND DISEASE PROGRESSION. 2021 6 2025 39 EPIGENETIC CHANGES DURING DISEASE PROGRESSION IN A MURINE MODEL OF HUMAN CHRONIC LYMPHOCYTIC LEUKEMIA. EPIGENETIC ALTERATIONS, INCLUDING GAIN OR LOSS OF DNA METHYLATION, ARE A HALLMARK OF NEARLY EVERY MALIGNANCY. CHANGES IN DNA METHYLATION CAN IMPACT EXPRESSION OF CANCER-RELATED GENES INCLUDING APOPTOSIS REGULATORS AND TUMOR SUPPRESSORS. BECAUSE SUCH EPIGENETIC CHANGES ARE REVERSIBLE, THEY ARE BEING AGGRESSIVELY INVESTIGATED AS POTENTIAL THERAPEUTIC TARGETS. HERE WE USE THE EMU-TCL1 TRANSGENIC MOUSE MODEL OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) TO DETERMINE THE TIMING AND PATTERNS OF ABERRANT DNA METHYLATION, AND TO INVESTIGATE THE MECHANISMS THAT LEAD TO ABERRANT DNA METHYLATION. WE SHOW THAT CLL CELLS FROM EMU-TCL1 MICE AT VARIOUS STAGES RECAPITULATE EPIGENETIC ALTERATIONS SEEN IN HUMAN CLL. ABERRANT METHYLATION OF PROMOTER SEQUENCES IS OBSERVED AS EARLY AS 3 MONTHS OF AGE IN THESE ANIMALS, WELL BEFORE DISEASE ONSET. ABNORMALLY METHYLATED PROMOTER REGIONS INCLUDE BINDING SITES FOR THE TRANSCRIPTION FACTOR FOXD3. WE SHOW THAT LOSS OF FOXD3 EXPRESSION DUE TO AN NF-KAPPAB P50/P50:HDAC1 REPRESSOR COMPLEX OCCURS IN TCL1-POSITIVE B CELLS BEFORE METHYLATION. THEREFORE, SPECIFIC TRANSCRIPTIONAL REPRESSION IS AN EARLY EVENT LEADING TO EPIGENETIC SILENCING OF TARGET GENES IN MURINE AND HUMAN CLL. THESE RESULTS PROVIDE STRONG RATIONALE FOR THE DEVELOPMENT OF STRATEGIES TO TARGET NF-KAPPAB COMPONENTS IN CLL AND POTENTIALLY OTHER B-CELL MALIGNANCIES. 2009 7 5475 35 RESTORING MLL REACTIVATES LATENT TUMOR SUPPRESSION-MEDIATED VULNERABILITY TO PROTEASOME INHIBITORS. MLL UNDERGOES MULTIPLE DISTINCT CHROMOSOMAL TRANSLOCATIONS TO YIELD AGGRESSIVE LEUKEMIA WITH DISMAL OUTCOMES. BESIDES THEIR WELL-ESTABLISHED ROLE IN LEUKEMOGENESIS, MLL FUSIONS ALSO POSSESS LATENT TUMOR-SUPPRESSIVE ACTIVITY, WHICH CAN BE EXPLOITED AS EFFECTIVE CANCER TREATMENT STRATEGIES USING PHARMACOLOGICAL MEANS SUCH AS PROTEASOME INHIBITORS (PIS). HERE, USING MLL-REARRANGED XENOGRAFTS AND MLL LEUKEMIC CELLS AS MODELS, WE SHOW THAT WILD-TYPE MLL IS INDISPENSABLE FOR THE LATENT TUMOR-SUPPRESSIVE ACTIVITY OF MLL FUSIONS. MLL DYSFUNCTION, SHOWN AS LOSS OF THE CHROMATIN ACCUMULATION AND SUBSEQUENT DEGRADATION OF MLL, COMPROMISES THE LATENT TUMOR SUPPRESSION OF MLL-AF4 AND IS INSTRUMENTAL FOR THE ACQUIRED PI RESISTANCE. MECHANISTICALLY, MLL DYSFUNCTION IS CAUSED BY CHRONIC PI TREATMENT-INDUCED EPIGENETIC REPROGRAMMING THROUGH THE H2BUB-ASH2L-MLL AXIS AND CAN BE SPECIFICALLY RESTORED BY HISTONE DEACETYLASE (HDAC) INHIBITORS, WHICH INDUCE HISTONE ACETYLATION AND RECRUITS MLL ON CHROMATIN TO PROMOTE CELL CYCLE GENE EXPRESSION. OUR FINDINGS NOT ONLY DEMONSTRATE THE MECHANISM UNDERLYING THE INEVITABLE ACQUISITION OF PI RESISTANCE IN MLL LEUKEMIC CELLS, BUT ALSO ILLUSTRATE THAT PREVENTING THE EMERGENCE OF PI-RESISTANT CELLS CONSTITUTES A NOVEL RATIONALE FOR COMBINATION THERAPY WITH PIS AND HDAC INHIBITORS IN MLL LEUKEMIAS. 2020 8 1902 34 ENHANCED EXPRESSION OF THE NUCLEAR ENVELOPE LAP2 TRANSCRIPTIONAL REPRESSORS IN NORMAL AND MALIGNANT ACTIVATED LYMPHOCYTES. EXTENSIVE RESEARCH IN RECENT YEARS HAS BROADENED THE FUNCTIONS OF NUCLEAR ENVELOPE PROTEINS BEYOND SIMPLY STABILIZING THE NUCLEUS ARCHITECTURE. PARTICULARLY, INTEGRAL NUCLEAR MEMBRANE PROTEINS, SUCH AS THE ALTERNATIVE SPLICED ISOFORMS OF LAMINA-ASSOCIATED POLYPEPTIDE 2 (LAP2), HAVE BEEN SHOWN TO BE IMPORTANT FOR THE INITIATION OF REPLICATION AND REPRESSION OF TRANSCRIPTION. THE LATTER IS REGULATED BY EPIGENETIC CHANGES, INDUCED BY THE BINDING OF LAP2BETA TO HISTONE DEACETYLASE-3 (HDAC3), RESULTING IN HISTONE H4 DEACETYLATION. INVOLVEMENT OF NUCLEAR ENVELOPE PROTEINS IN PATHOLOGICAL PROLIFERATIVE CONDITIONS, MAINLY THOSE INVOLVING ABNORMAL RECRUITMENT AND ACTIVATION OF HDACS, IS STILL UNKNOWN. IN THIS PAPER, WE SHOW THAT VARIOUS NUCLEAR ENVELOPE PROTEINS ARE HIGHLY EXPRESSED IN NORMAL AND MALIGNANT ACTIVATED LYMPHOCYTES. SPECIFICALLY, RAPIDLY REPLICATING CELLS OF VARIOUS HEMATOLOGICAL MALIGNANCIES HIGHLY EXPRESS LAP2BETA, WHILE SLOWLY PROLIFERATING MALIGNANT CELLS OF CHRONIC MALIGNANT HEMATOLOGICAL DISEASES DO NOT. TAKING TOGETHER THE ELEVATED EXPRESSION OF LAP2BETA IN HIGHLY PROLIFERATIVE MALIGNANT CELLS WITH ITS KNOWN ABILITY TO MODIFY HISTONES THROUGH BINDING WITH HDAC3 RAISES THE POSSIBILITY OF ITS ROLE IN HEMATOLOGICAL MALIGNANCIES INVOLVING ABERRANT ACTIVITY OF HDAC3. BASED ON OUR PRESENTED RESULTS, WE BELIEVE THAT THE LAP2-HDAC REGULATORY PATHWAY SHOULD BE STUDIED AS A NEW TARGET FOR RATIONAL THERAPY. 2007 9 4877 36 OVEREXPRESSION OF MIR-4433 BY SUBEROYLANILIDE HYDROXAMIC ACID SUPPRESSES GROWTH OF CML CELLS AND INDUCES APOPTOSIS THROUGH TARGETING BCR-ABL. BACKGROUND: TARGETING BCR-ABL IS THE KEY FOR THE TREATMENT OF CML. ALTHOUGH GREAT PROGRESS HAS BEEN ACHIEVED FOR THE TREATMENT OF CML PATIENTS IN CHRONIC STAGE, EFFECTIVE DRUGS WITH GOOD SAFETY ARE NOT AVAILABLE FOR THOSE IN ADVANCED STAGES OF CML PATIENTS. IN PRESENT STUDY, A HISTONE DEACETYLASE INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), WAS USED TO SCREEN FOR MICRORNA THAT CAN TARGET BCR-ABL. METHODS: RT-QPCR WAS USED TO DETERMINE BCR-ABL AND MIR-4433 TRANSCRIPTION LEVEL IN CML CELLS. IN CML CELLS, PROTEINS INCLUDING PARP, CASPASE-3, ACETYL-HISTONE 3, HISTONE 3 AND BCR-ABL, AS WELL AS BCR-ABL DOWNSTREAM PROTEINS WERE DETECTED USING WESTERN BLOT. CELL VIABILITY AND APOPTOSIS WERE MONITORED RESPECTIVELY BY MTS ASSAY AND FLOW CYTOMETRY. THE CORRELATION BETWEEN MIR-4433 AND BCR-ABL WAS DETERMINED BY LUCIFERASE REPORTER ASSAY. THE ANTI-TUMOR EFFECT OF MIR-4433 TO K562 CELLS WAS EVALUATED BY NUDE MOUSE XENOGRAFT MODEL IN VIVO. RESULTS: SAHA UP-REGULATED THE ACETYLATION LEVEL OF HISTONE 3, AND EFFECTIVELY INHIBITED BCR-ABL MRNA LEVEL AND ITS DOWNSTREAM SIGNAL TRANSDUCTION PATHWAY, WHILE INHIBITING THE GROWTH OF CML CELLS AND INDUCING APOPTOSIS. FURTHERMORE, BIOINFORMATICS TOOLS PREDICTED THAT MIR-4433 IS A PUTATIVE MICRORNA TARGETING BCR-ABL AND THAT THE EXPRESSION LEVEL OF MIR-4433 WAS SIGNIFICANTLY INCREASED AFTER SAHA TREATMENT IN K562 CELLS. LUCIFERASE ACTIVITY ANALYSIS REVEALED THAT MIR-4433 DIRECTLY TARGETS BCR-ABL. ADDITIONALLY, TRANSIENT EXPRESSION OF MIR-4433 ABROGATED BCR-ABL ACTIVITY AND ITS DOWNSTREAM SIGNALING PATHWAYS WHILE INDUCING APOPTOSIS IN K562 CELLS. MOREOVER, STABLE EXPRESSION OF MIR-4433 SUPPRESSED BCR-ABL AND ITS DOWNSTREAM SIGNALING PATHWAY, AND INHIBITED THE GROWTH OF K562 CELLS IN VITRO AND THE GROWTH OF K562-XENOGRAFTS IN NUDE MICE. CONCLUSION: MIR-4433 WAS IDENTIFIED AS A MICRORNA TARGETING BCR-ABL, WHICH MAY BE SUBJECT TO EPIGENETIC REGULATION OF SAHA, A HISTONE DEACETYLASE INHIBITOR THAT HAS BEEN APPROVED BY THE US FDA FOR THE TREATMENT OF CUTANEOUS T-CELL LYMPHOMA. THE FINDINGS OF THIS STUDY PROVIDE A MOLECULAR BASIS FROM ANOTHER ANGLE FOR THE USE OF SAHA IN THE TREATMENT OF CML. 2019 10 3527 32 IL-6 ENHANCES THE NUCLEAR TRANSLOCATION OF DNA CYTOSINE-5-METHYLTRANSFERASE 1 (DNMT1) VIA PHOSPHORYLATION OF THE NUCLEAR LOCALIZATION SEQUENCE BY THE AKT KINASE. THE EPIGENETIC PROGRAMMING OF GENOMIC DNA IS ACCOMPLISHED, IN PART, BY SEVERAL DNA CYTOSINE-5-METHYLTRANSFERASES THAT ACT BY COVALENTLY MODIFYING CYTOSINES WITH THE ADDITION OF A METHYL GROUP. THIS COVALENT MODIFICATION IS MAINTAINED BY THE DNA CYTOSINE-5-METHYLTRANSFERASE-1 ENZYME (DNMT1), WHICH IS CAPABLE OF ACTING IN CONCERT WITH OTHER SIMILAR ENZYMES TO SILENCE IMPORTANT TUMOR SUPPRESSOR GENES. IL-6 IS A MULTIFUNCTIONAL MEDIATOR OF INFLAMMATION, ACTING THROUGH SEVERAL MAJOR SIGNALING CASCADES, INCLUDING THE PHOSPHATIDYLINOSITOL-3-KINASE PATHWAY (PI-3-K), WHICH ACTIVATES PROTEIN KINASE B (AKT/PKB) DOWNSTREAM. HERE, WE SHOW THAT THE SUBCELLULAR LOCALIZATION OF DNMT1 CAN BE ALTERED BY THE ADDITION OF IL-6, INCREASING THE RATE OF NUCLEAR TRANSLOCATION OF THE ENZYME FROM THE CYTOSOLIC COMPARTMENT. THE MECHANISM OF NUCLEAR TRANSLOCATION OF DNMT1 IS GREATLY ENHANCED BY PHOSPHORYLATION OF THE DNMT1 NUCLEAR LOCALIZATION SIGNAL (NLS) BY PKB/AKT KINASE. MUTAGENIC ALTERATION OF THE TWO AKT TARGET AMINO ACIDS WITHIN THE NLS RESULTS IN A MAJOR LOSS OF DNMT1 NUCLEAR TRANSLOCATION, WHILE THE CREATION OF A "PHOSPHO-MIMIC" AMINO ACID (MUTATION TO ACIDIC RESIDUES) RESTORES THIS COMPARTMENTATION ABILITY. THESE OBSERVATIONS SUGGEST AN INTERESTING HYPOTHESIS REGARDING HOW MEDIATORS OF CHRONIC INFLAMMATION MAY DISTURB THE DELICATE BALANCE OF CELLULAR COMPARTMENTALIZATION OF IMPORTANT PROTEINS, AND REVEALS A POTENTIAL MECHANISM FOR THE INDUCTION OR ENHANCEMENT OF TUMOR GROWTH VIA ALTERATION OF THE COMPONENTS INVOLVED IN THE EPIGENETIC PROGRAMMING OF A CELL. 2007 11 942 32 CHRONIC LYMPHOCYTIC LEUKEMIA PRESENCE IMPAIRS ANTIGEN-SPECIFIC CD8(+) T-CELL RESPONSES THROUGH EPIGENETIC REPROGRAMMING TOWARDS SHORT-LIVED EFFECTORS. T-CELL DYSREGULATION IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) ASSOCIATES WITH LOW RESPONSE RATES TO AUTOLOGOUS T CELL-BASED THERAPIES. HOW CLL AFFECTS ANTIGEN-SPECIFIC T-CELL RESPONSES REMAINS LARGELY UNKNOWN. WE INVESTIGATED (EPI)GENETIC AND FUNCTIONAL CONSEQUENCES OF ANTIGEN-SPECIFIC T-CELL RESPONSES IN PRESENCE OF CLL IN VITRO AND IN AN ADOPTIVE-TRANSFER MURINE MODEL. ALREADY AT STEADY-STATE, ANTIGEN-EXPERIENCED PATIENT-DERIVED T CELLS WERE SKEWED TOWARDS SHORT-LIVED EFFECTOR CELLS (SLEC) AT THE EXPENSE OF MEMORY-PRECURSOR EFFECTOR CELLS (MPEC). STIMULATION OF THESE T CELLS IN VITRO SHOWED RAPID INDUCTION OF EFFECTOR GENES AND SUPPRESSION OF KEY MEMORY TRANSCRIPTION FACTORS ONLY IN PRESENCE OF CLL CELLS, INDICATING EPIGENETIC REGULATION. THIS WAS INVESTIGATED IN VIVO BY FOLLOWING ANTIGEN-SPECIFIC RESPONSES OF NAIVE OT-I CD8(+) CELLS TO MCMV-OVA IN PRESENCE/ABSENCE OF TCL1 B-CELL LEUKEMIA. PRESENCE OF LEUKEMIA RESULTED IN INCREASED SLEC FORMATION, WITH DISTURBED INFLAMMATORY CYTOKINE PRODUCTION. CHROMATIN AND TRANSCRIPTOME PROFILING REVEALED STRONG EPIGENETIC MODIFICATIONS, LEADING TO ACTIVATION OF AN EFFECTOR AND SILENCING OF A MEMORY PROFILE THROUGH PRESENCE OF CLL CELLS. SECONDARY CHALLENGE IN VIVO CONFIRMED DYSFUNCTIONAL MEMORY RESPONSES BY ANTIGEN-EXPERIENCED OT-I CELLS GENERATED IN PRESENCE OF CLL. ALTOGETHER, WE SHOW THAT PRESENCE OF CLL INDUCES A SHORT-LIVED EFFECTOR PHENOTYPE AND IMPAIRED MEMORY RESPONSES BY EPIGENETIC REPROGRAMMING DURING PRIMARY RESPONSES. 2023 12 1976 32 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 5088 38 PIPERLONGUMINE REGULATES EPIGENETIC MODULATION AND ALLEVIATES PSORIASIS-LIKE SKIN INFLAMMATION VIA INHIBITION OF HYPERPROLIFERATION AND INFLAMMATION. PSORIASIS IS AN AUTOIMMUNE SKIN DISEASE, WHERE CHRONIC IMMUNE RESPONSES DUE TO EXAGGERATED CYTOKINE SIGNALING, ABNORMAL DIFFERENTIATION, AND EVASION OF KERATINOCYTES APOPTOSIS PLAYS A CRUCIAL ROLE IN MEDIATING ABNORMAL KERATINOCYTES HYPERPROLIFERATION. FROM THE THERAPEUTIC PERSPECTIVE, THE MOLECULES WITH STRONG ANTI-PROLIFERATIVE AND ANTI-INFLAMMATORY PROPERTIES COULD HAVE TREMENDOUS RELEVANCE. IN THIS STUDY, WE DEMONSTRATED THAT PIPERLONGUMINE (PPL) TREATMENT EFFECTIVELY ABROGATED THE HYPERPROLIFERATION AND DIFFERENTIATION OF KERATINOCYTES BY INDUCING ROS-MEDIATED LATE APOPTOSIS WITH LOSS OF MITOCHONDRIAL MEMBRANE POTENTIAL. BESIDES, THE ARREST OF CELL CYCLE WAS FOUND AT SUB-G1 PHASE AS A RESULT OF DNA FRAGMENTATION. MOLECULARLY, INHIBITION OF STAT3 AND AKT SIGNALING WAS OBSERVED WITH A DECREASE IN PROLIFERATIVE MARKERS SUCH AS PCNA, KI67, AND CYCLIN D1 ALONG WITH ANTI-APOPTOTIC BCL-2 PROTEIN EXPRESSION. KERATIN 17 IS A CRITICAL REGULATOR OF KERATINOCYTE DIFFERENTIATION, AND IT WAS FOUND TO BE DOWNREGULATED WITH PPL SIGNIFICANTLY. FURTHERMORE, PROMINENT ANTI-INFLAMMATORY EFFECTS WERE OBSERVED BY INHIBITION OF LIPOPOLYSACCHARIDE (LPS)/IMIQUIMOD (IMQ)-INDUCED P65 NF-KAPPAB SIGNALING CASCADE AND STRONGLY INHIBITED THE PRODUCTION OF CYTOKINE STORM INVOLVED IN PSORIASIS-LIKE SKIN INFLAMMATION, THUS LED TO THE RESTORATION OF NORMAL EPIDERMAL ARCHITECTURE WITH REDUCTION OF EPIDERMAL HYPERPLASIA AND SPLENOMEGALY. IN ADDITION, PPL EPIGENETICALLY INHIBITED HISTONE-MODIFYING ENZYMES, WHICH INCLUDE HISTONE DEACETYLASES (HDACS) OF CLASS I (HDAC1-4) AND CLASS II (HDAC6) EVALUATED BY IMMUNOBLOTTING AND HDAC ENZYME ASSAY KIT. IN ADDITION, OUR RESULTS SHOW THAT PPL EFFECTIVELY INHIBITS THE NUCLEAR TRANSLOCATION OF P65 AND A HISTONE MODULATOR HDAC3, THUS SEQUESTERED IN THE CYTOPLASM OF MACROPHAGES. FURTHERMORE, PPL EFFECTIVELY ENHANCED THE PROTEIN-PROTEIN INTERACTIONS OF HDAC3 AND P65 WITH IKAPPABALPHA, WHICH WAS DISRUPTED BY LPS STIMULATION AND WERE EVALUATED BY CO-IP AND MOLECULAR MODELING. COLLECTIVELY, OUR FINDINGS INDICATE THAT PIPERLONGUMINE MAY SERVE AS AN ANTI-PROLIFERATIVE AND ANTI-INFLAMMATORY AGENT AND COULD SERVE AS A POTENTIAL THERAPEUTIC OPTION IN TREATING PSORIASIS. 2020 14 402 30 ANALYSIS OF APOPTOSOME DYSREGULATION IN PANCREATIC CANCER AND OF ITS ROLE IN CHEMORESISTANCE. THE APOPTOSOME IS A MULTIPROTEIN COMPLEX MEDIATING THE MITOCHONDRIAL PATHWAY OF CELL DEATH. ITS IMPORTANCE DURING DEVELOPMENT HAS BEEN CLEARLY DEMONSTRATED BY KNOCKING OUT KEY GENES IN MOUSE. APAF1 IS THE CORE PROTEIN OF THE APOPTOSOME AND ITS DOSAGE IS ALSO CRITICAL IN VARIOUS CANCER TYPES, I.E., MELANOMA, GERM LINE TUMOR, GASTROINTESTINAL CANCER AND B-TYPE CHRONIC LYMPHOCYTIC LEUKEMIA. THIS IS GENERALLY DUE TO INACTIVATION OF THE APAF1 LOCUS BY EPIGENETIC PHENOMENA OR BY ACTIVITY OF PROMOTER REGULATORS. WE INVESTIGATED THE PUTATIVE ROLES OF THE APOPTOSOME IN PANCREATIC DUCTAL ADENOCARCINOMA (PDAC). WE FOUND THAT BOTH APAF1 MRNA AND PROTEIN ARE DYSREGULATED IN HUMAN PDAC SAMPLES. SIMILARLY, SEVERAL PDAC CELL LINES EXHIBITED VARIABLE LEVELS OF BOTH APAF1 PROTEIN AND MRNA. THE RESPONSE TO CELL DEATH INDUCTION AND ITS BIOCHEMICAL FEATURES WERE ASSESSED BY TREATMENT OF EACH LINE WITH COMMONLY USED CHEMOTHERAPEUTIC AGENTS. WE FOUND THAT THE APOPTOSOME PATHWAY WAS NOT FUNCTIONAL IN MOST CELL LINES UPON CYTOCHROME C RELEASE FROM MITOCHONDRIA. IN ADDITION, WE RESTORED APAF1 AND CASPASE-9 DOSAGE IN PANC-1 CELLS, WHERE THE APOPTOSOME IS DOWNREGULATED, BY OVEREXPRESSING THE MURINE CDNA OF THE TWO MOLECULES, AND WE IMPROVED THE DEATH RESPONSE TO CHEMOTHERAPEUTIC AGENTS. 2007 15 2389 35 EPIGENETIC REPOLARIZATION OF T LYMPHOCYTES FROM CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS USING 5-AZA-2'-DEOXYCYTIDINE. T CELL IMMUNE DYSFUNCTION HAS AN IMPORTANT ROLE IN THE PROFOUND IMMUNE SUPPRESSION THAT CHARACTERIZES CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). IMPROPER POLARIZATION OF T CELLS HAS BEEN PROPOSED AS ONE OF THE MECHANISM INVOLVED. MOUNTING DATA IMPLICATES CHROMATIN REGULATION, NAMELY PROMOTER METHYLATION, IN THE PLASTICITY OF NAIVE HUMAN T CELLS. RECENT IN VITRO EVIDENCE INDICATES THAT THIS PLASTICITY MAY BE PHENOTYPICALLY ALTERED BY USING METHYLATION INHIBITORS WHICH ARE APPROVED FOR CLINICAL USE IN CERTAIN TYPES OF CANCER. THESE RESULTS BEG THE QUESTION: CAN THE INEFFECTIVE POLARIZATION OF T LYMPHOCYTES IN THE CONTEXT OF CLL BE EFFECTIVELY MODULATED USING METHYLATION INHIBITORS IN A SUSTAINABLE THERAPEUTIC FASHION? TO ANSWER THIS QUESTION OUR LABORATORY HAS STUDIED THE EFFECTS OF 5-AZA-2'-DEOXYCYTIDINE (5A2) IN HELPER AND CYTOTOXIC T LYMPHOCYTES FROM HEALTHY DONORS AND CLL PATIENTS IN WELL CHARACTERIZED MOLECULAR AND EPIGENETIC SIGNALING PATHWAYS INVOLVED IN EFFECTIVE POLARIZATION. MOREOVER, WE SOUGHT TO INVESTIGATE THE CONSEQUENCES OF METHYLATION INHIBITOR TREATMENT ON LYMPHOCYTE SURVIVAL, ACTIVATION INTENSITY, AND NAIVE CELL POLARIZATION. OUR DATA INDICATES THAT 5A2 TREATMENT CAN DEPOLARIZE TH2 CELLS TO EFFECTIVELY SECRETE INTERFERON GAMMA, SIGNAL VIA T-BET, AND ACHIEVE DEMETHYLATION OF CRITICAL TH1 SPECIFIC PROMOTERS. MOREOVER, WE DEMONSTRATE THAT 5A2 CAN FORCE TH1 POLARIZATION OF NAIVE T CELLS DESPITE A STRONG IL-4 STIMULI AND A LACK OF IL-12. IN CONCLUSION OUR DATA SEEKS TO DEFINE A MODALITY IN WHICH IMPROPER OR INEFFECTIVE T CELL POLARIZATION CAN BE ALTERED BY 5AZA AND COULD BE INCORPORATED IN FUTURE THERAPEUTIC INTERVENTIONS. 2011 16 5972 22 TET REPRESSION AND INCREASED DNMT ACTIVITY SYNERGISTICALLY INDUCE ABERRANT DNA METHYLATION. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN VARIOUS HUMAN DISORDERS, SUCH AS CANCER, NEURODEGENERATIVE DISORDERS, AND METABOLIC DISORDERS. INDUCTION OF EPIGENETIC ALTERATIONS, ESPECIALLY ABERRANT DNA METHYLATION, IS ONE OF THE MAJOR MECHANISMS, BUT HOW IT IS INDUCED IS STILL UNCLEAR. HERE, WE FOUND THAT EXPRESSION OF TET GENES, METHYLATION ERASERS, WAS DOWNREGULATED IN INFLAMED MOUSE AND HUMAN TISSUES, AND THAT THIS WAS CAUSED BY UPREGULATION OF TET-TARGETING MIRNAS SUCH AS MIR20A, MIR26B, AND MIR29C, LIKELY DUE TO ACTIVATION OF NF-KAPPAB SIGNALING DOWNSTREAM OF IL-1BETA AND TNF-ALPHA. HOWEVER, TET KNOCKDOWN INDUCED ONLY MILD ABERRANT METHYLATION. NITRIC OXIDE (NO), PRODUCED BY NOS2, ENHANCED ENZYMATIC ACTIVITY OF DNA METHYLTRANSFERASES (DNMTS), METHYLATION WRITERS, AND NO EXPOSURE INDUCED MINIMAL ABERRANT METHYLATION. IN CONTRAST, A COMBINATION OF TET KNOCKDOWN AND NO EXPOSURE SYNERGISTICALLY INDUCED ABERRANT METHYLATION, INVOLVING GENOMIC REGIONS NOT METHYLATED BY EITHER ALONE. THE RESULTS SHOWED THAT A VICIOUS COMBINATION OF TET REPRESSION, DUE TO NF-KAPPAB ACTIVATION, AND DNMT ACTIVATION, DUE TO NO PRODUCTION, IS RESPONSIBLE FOR ABERRANT METHYLATION INDUCTION IN HUMAN TISSUES. 2020 17 1733 40 E-CADHERIN GENE RE-EXPRESSION IN CHRONIC LYMPHOCYTIC LEUKEMIA CELLS BY HDAC INHIBITORS. BACKGROUND: THE TUMOR SUPPRESSOR GENE E-CADHERIN GENE IS FREQUENTLY SILENCED IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) CELLS AND RESULTS IN WNT-PATHWAY ACTIVATION. WE ANALYZED THE ROLE OF HISTONE EPIGENETIC MODIFICATIONS IN E-CADHERIN GENE SILENCING. METHODS: CLL SPECIMENS WERE TREATED WITH HISTONE DEACETYLASE INHIBITOR (HDACI) MS-275 AND ANALYZED FOR E-CADHERIN EXPRESSION WITH WESTERN BLOT AND RT-PCR ANALYSIS. THE DOWNSTREAM EFFECTS OF HDACI TREATED LEUKEMIC CELLS WERE STUDIED BY ANALYZING THE EFFECT ON WNT-PATHWAY SIGNALING. HDACI INDUCED ALTERATIONS IN E-CADHERIN SPLICING WERE INVESTIGATED BY TRANSCRIPT SPECIFIC REAL TIME PCR ANALYSIS. RESULTS: TREATMENT OF CLL SPECIMENS WITH HISTONE DEACETYLASE INHIBITORS (HDACI) TREATMENT RESULTED IN AN INCREASE OF THE E-CADHERIN RNA TRANSCRIPT (5 TO 119 FOLD INCREASE, N=10) IN EIGHT OUT OF TEN CLL SPECIMENS INDICATING THAT THIS GENE IS DOWN REGULATED BY HISTONE HYPOACETYLATION IN A MAJORITY OF CLL SPECIMENS. THE E-CADHERIN RE-EXPRESSION IN CLL SPECIMENS WAS NOTED BY WESTERN BLOT ANALYSIS AS WELL. BESIDES EPIGENETIC SILENCING ANOTHER MECHANISM OF E-CADHERIN INACTIVATION IS ABERRANT EXON 11 SPLICING RESULTING IN AN ALTERNATIVELY SPLICED TRANSCRIPT THAT LACKS EXON 11 AND IS DEGRADED BY THE NON-SENSE MEDIATED DECAY (NMD) PATHWAY. OUR CHROMATIN IMMUNOPRECIPITATION EXPERIMENTS SHOW THAT HDACI INCREASED THE ACETYLATION OF HISTONES H3 AND H4 IN THE E-CADHERIN PROMOTER REGION. THIS ALSO AFFECTED THE E-CADHERIN EXON 11 SPLICING PATTERN AS HDACI TREATED CLL SPECIMENS PREFERENTIALLY EXPRESSED THE CORRECTLY SPLICED TRANSCRIPT AND NOT THE EXON 11 SKIPPED ABERRANT TRANSCRIPT. THE RE-EXPRESSED E- CADHERIN BINDS TO BETA-CATENIN WITH INHIBITION OF THE ACTIVE WNT-BETA-CATENIN PATHWAY IN THESE CELLS. THIS RESULTED IN A DOWN REGULATION OF TWO WNT TARGET GENES, LEF AND CYCLIND1 AND THE WNT PATHWAY REPORTER. CONCLUSION: THE E-CADHERIN GENE IS EPIGENETICALLY MODIFIED AND HYPOACETYLATED IN CLL LEUKEMIC CELLS. TREATMENT OF CLL SPECIMENS WITH HDACI MS-275 ACTIVATES TRANSCRIPTION FROM THIS SILENT GENE WITH EXPRESSION OF MORE CORRECTLY SPLICED E-CADHERIN TRANSCRIPTS AS COMPARED TO THE ABERRANT EXON11 SKIPPED TRANSCRIPTS THAT IN TURN INHIBITS THE WNT SIGNALING PATHWAY. THE DATA HIGHLIGHTS THE ROLE OF EPIGENETIC MODIFICATIONS IN ALTERING GENE SPLICING PATTERNS. 2013 18 171 33 ABROGATION OF HISTONE DEACETYLASES (HDACS) DECREASES SURVIVAL OF CHRONIC MYELOID LEUKEMIA CELLS: NEW INSIGHT INTO ATTENUATING EFFECTS OF THE PI3K/C-MYC AXIS ON PANOBINOSTAT CYTOTOXICITY. ALTHOUGH THE IDENTIFICATION OF TYROSINE KINASE INHIBITORS (TKIS) HAS CHANGED THE TREATMENT PARADIGM OF MANY CANCER TYPES INCLUDING CHRONIC MYELOID LEUKEMIA (CML), STILL ADJUSTMENT OF NEOPLASTIC CELLS TO CYTOTOXIC EFFECTS OF ANTICANCER DRUGS IS A SERIOUS CHALLENGE. IN THE AREA OF DRUG RESISTANCE, EPIGENETIC ALTERATIONS ARE AT THE CENTER OF ATTENTION AND THE PRESENT STUDY AIMED TO EVALUATE WHETHER BLOCKAGE OF EPIGENETICS MECHANISMS USING A PAN-HISTONE DEACETYLASE (HDAC) INHIBITOR INDUCES CELL DEATH IN CML-DERIVED K562 CELLS. WE FOUND THAT THE ABROGATION OF HDACS USING PANOBINOSTAT RESULTED IN A REDUCTION IN SURVIVAL OF THE K562 CELL LINE THROUGH P27-MEDIATED CELL CYCLE ARREST. NOTEWORTHY, THE RESULTS OF THE SYNERGISTIC EXPERIMENTS REVEALED THAT HDAC SUPPRESSION COULD BE RECRUITED AS A WAY TO POTENTIATE CYTOTOXICITY OF IMATINIB AND TO ENHANCE THE THERAPEUTIC EFFICACY OF CML. HERE, WE PROPOSED FOR THE FIRST TIME THAT THE INHIBITORY EFFECT OF PANOBINOSTAT WAS OVERSHADOWED, AT LEAST PARTIALLY, THROUGH THE ABERRANT ACTIVATION OF THE PHOSPHOINOSITIDE 3-KINASE (PI3K)/C-MYC AXIS. MEANWHILE, WE FOUND THAT UPON BLOCKAGE OF AUTOPHAGY AND THE PROTEASOME PATHWAY, AS THE MAIN AXIS INVOLVED IN THE ACTIVATION OF AUTOPHAGY, THE ANTI-LEUKEMIC PROPERTY OF THE HDAC INHIBITOR WAS POTENTIATED. TAKEN TOGETHER, OUR STUDY SUGGESTS THE BENEFICIAL APPLICATION OF HDAC INHIBITION IN THE TREATMENT STRATEGIES OF CML; HOWEVER, FURTHER IN VIVO STUDIES ARE NEEDED TO DETERMINE THE EFFICACY OF THIS INHIBITOR, EITHER AS A SINGLE AGENT OR IN COMBINATION WITH SMALL MOLECULE INHIBITORS OF PI3K AND/OR C-MYC IN THIS MALIGNANCY. 2021 19 5920 31 TARGETING CHROMATIN REMODELING IN INFLAMMATION AND FIBROSIS. MUCOSAL SURFACES OF THE HUMAN BODY ARE LINED BY A CONTIGUOUS EPITHELIAL CELL SURFACE THAT FORMS A BARRIER TO AEROSOLIZED PATHOGENS. SPECIALIZED PATTERN RECOGNITION RECEPTORS DETECT THE PRESENCE OF VIRAL PATHOGENS AND INITIATE PROTECTIVE HOST RESPONSES BY TRIGGERING ACTIVATION OF THE NUCLEAR FACTOR KAPPAB (NFKAPPAB)/RELA TRANSCRIPTION FACTOR AND FORMATION OF A COMPLEX WITH THE POSITIVE TRANSCRIPTION ELONGATION FACTOR (P-TEFB)/CYCLIN-DEPENDENT KINASE (CDK)9 AND BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4) EPIGENETIC READER. THE RELA.BRD4.P-TEFB COMPLEX PRODUCES ACUTE INFLAMMATION BY REGULATING TRANSCRIPTIONAL ELONGATION, WHICH PRODUCES A RAPID GENOMIC RESPONSE BY INACTIVE GENES MAINTAINED IN AN OPEN CHROMATIN CONFIGURATION ENGAGED WITH HYPOPHOSPHORYLATED RNA POLYMERASE II. WE DESCRIBE RECENT STUDIES THAT HAVE LINKED PROLONGED ACTIVATION OF THE RELA-BRD4 PATHWAY WITH THE EPITHELIAL-MESENCHYMAL TRANSITION (EMT) BY INDUCING A CORE OF EMT COREPRESSORS, STIMULATING SECRETION OF GROWTH FACTORS PROMOTING AIRWAY FIBROSIS. THE MESENCHYMAL STATE PRODUCES REWIRING OF THE KINOME AND REPROGRAMMING OF INNATE RESPONSES TOWARD INFLAMMATION. IN ADDITION, THE CORE REGULATOR ZINC FINGER E-BOX HOMEODOMAIN 1 (ZEB1) SILENCES THE EXPRESSION OF THE INTERFERON RESPONSE FACTOR 1 (IRF1), REQUIRED FOR TYPE III IFN EXPRESSION. THIS EPIGENETIC SILENCING IS MEDIATED BY THE ENHANCER OF ZESTE 2 (EZH2) HISTONE METHYLTRANSFERASE. BECAUSE OF THEIR POTENTIAL APPLICATIONS IN CANCER AND INFLAMMATION, SMALL-MOLECULE INHIBITORS OF NFKAPPAB/RELA, CDK9, BRD4, AND EZH2 HAVE BEEN THE TARGETS OF MEDICINAL CHEMISTRY EFFORTS. WE SUGGEST THAT DISRUPTION OF THE RELA.BRD4.P-TEFB PATHWAY AND EZH2 METHYLTRANSFERASE HAS IMPORTANT IMPLICATIONS FOR REVERSING FIBROSIS AND RESTORING NORMAL MUCOSAL IMMUNITY IN CHRONIC INFLAMMATORY DISEASES. 2017 20 4839 42 ONCOGENIC ROLE AND TARGET PROPERTIES OF THE LYSINE-SPECIFIC DEMETHYLASE KDM1A IN CHRONIC LYMPHOCYTIC LEUKEMIA. IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), EPIGENETIC ALTERATIONS ARE CONSIDERED TO CENTRALLY SHAPE THE TRANSCRIPTIONAL SIGNATURES THAT DRIVE DISEASE EVOLUTION AND UNDERLIE ITS BIOLOGICAL AND CLINICAL SUBSETS. CHARACTERIZATIONS OF EPIGENETIC REGULATORS, PARTICULARLY HISTONE-MODIFYING ENZYMES, ARE VERY RUDIMENTARY IN CLL. IN EFFORTS TO ESTABLISH EFFECTORS OF THE CLL-ASSOCIATED ONCOGENE T-CELL LEUKEMIA 1A (TCL1A), WE IDENTIFIED HERE THE LYSINE-SPECIFIC HISTONE DEMETHYLASE KDM1A TO INTERACT WITH THE TCL1A PROTEIN IN B CELLS IN CONJUNCTION WITH AN INCREASED CATALYTIC ACTIVITY OF KDM1A. WE DEMONSTRATE THAT KDM1A IS UPREGULATED IN MALIGNANT B CELLS. ELEVATED KDM1A AND ASSOCIATED GENE EXPRESSION SIGNATURES CORRELATED WITH AGGRESSIVE DISEASE FEATURES AND ADVERSE CLINICAL OUTCOMES IN A LARGE PROSPECTIVE CLL TRIAL COHORT. GENETIC KDM1A KNOCKDOWN IN EMU-TCL1A MICE REDUCED LEUKEMIC BURDEN AND PROLONGED ANIMAL SURVIVAL, ACCOMPANIED BY UPREGULATED P53 AND PROAPOPTOTIC PATHWAYS. GENETIC KDM1A DEPLETION ALSO AFFECTED MILIEU COMPONENTS (T, STROMAL, AND MONOCYTIC CELLS), RESULTING IN SIGNIFICANT REDUCTIONS IN THEIR CAPACITY TO SUPPORT CLL-CELL SURVIVAL AND PROLIFERATION. INTEGRATED ANALYSES OF DIFFERENTIAL GLOBAL TRANSCRIPTOMES (RNA SEQUENCING) AND H3K4ME3 MARKS (CHROMATIN IMMUNOPRECIPITATION SEQUENCING) IN EMU-TCL1A VS IKDM1AKD;EMU-TCL1A MICE (CONFIRMED IN HUMAN CLL) IMPLICATE KDM1A AS AN ONCOGENIC TRANSCRIPTIONAL REPRESSOR IN CLL WHICH ALTERS HISTONE METHYLATION PATTERNS WITH PRONOUNCED EFFECTS ON DEFINED CELL DEATH AND MOTILITY PATHWAYS. FINALLY, PHARMACOLOGIC KDM1A INHIBITION ALTERED H3K4/9 TARGET METHYLATION AND REVEALED MARKED ANTI-B-CELL LEUKEMIC SYNERGISMS. OVERALL, WE ESTABLISHED THE PATHOGENIC ROLE AND EFFECTOR NETWORKS OF KDM1A IN CLL VIA TUMOR-CELL INTRINSIC MECHANISMS AND ITS IMPACTS IN CELLS OF THE MICROENVIRONMENT. OUR DATA ALSO PROVIDE RATIONALES TO FURTHER INVESTIGATE THERAPEUTIC KDM1A TARGETING IN CLL. 2023