1 787 110 CELLS OF ADULT T-CELL LEUKEMIA EVADE HTLV-1 TAX/NF-KAPPAB HYPERACTIVATION-INDUCED SENESCENCE. HUMAN T-CELL LEUKEMIA VIRUS TYPE 1 (HTLV-1) IS THE ETIOLOGICAL AGENT OF ADULT T-CELL LEUKEMIA/LYMPHOMA (ATL). THE HTLV-1 VIRAL TRANS-ACTIVATOR/ONCOPROTEIN TAX IS A MAJOR DRIVER OF ATL, YET IT INDUCES RAPID P21(CIP1/WAF1) (P21)- AND P27(KIP1)-MEDIATED CELLULAR SENESCENCE THROUGH CONSTITUTIVE ACTIVATION (HYPERACTIVATION) OF NF-KAPPAB. ALTHOUGH CONSTITUTIVE NF-KAPPAB ACTIVATION IS A COMMON FEATURE OF T/B-CELL LEUKEMIA/LYMPHOMA, INCLUDING ATL, IT IS NOT KNOWN HOW ATL CELLS MAINTAIN CHRONIC NF-KAPPAB ACTIVATION WITHOUT UNDERGOING SENESCENCE. HERE, WE DEMONSTRATE THAT, IN CONTRAST TO HTLV-1(-) T-CELL LINES, ATL CELL LINES NO LONGER UNDERGO TAX-INDUCED SENESCENCE. ALTHOUGH TAX(+) AND TAX(-) ATL CELL LINES SHOWED SIGNATURES OF CONSTITUTIVE NF-KAPPAB ACTIVATION, THEIR ABILITY TO PROGRESS THROUGH THE CELL CYCLE WAS UNAFFECTED. IN SOME CASES, ATL CELL LINES CONTINUED TO PROLIFERATE DESPITE SIGNIFICANT UPREGULATION OF P21; ADDITIONALLY, MANY CELL LINES DISPLAYED ALTERED EXPRESSION OF G1 AND G1/S CYCLINS, PARTICULARLY OVEREXPRESSION OF CYCLIN D2. WE PROPOSE THAT, DURING THE COURSE OF ATL DEVELOPMENT, LEUKEMIA CELLS ACQUIRE GENETIC/EPIGENETIC CHANGES THAT CAN MITIGATE THE SENESCENCE RESPONSE TRIGGERED BY NF-KAPPAB HYPERACTIVATION. RESTORING THE NF-KAPPAB-INDUCED SENESCENCE RESPONSE WOULD LIKELY HELP TO CONTROL THE DEVELOPMENT AND PROGRESSION OF ATL AND SIMILAR LYMPHOID MALIGNANCIES. 2019 2 6789 24 [CURRENT STATUS OF ATL RESEARCH: EFFORTS FOR PREVENTION AND PRECISION MEDICINE FOR ATL]. THE INTRODUCTION OF NEW AGENTS AND HEMATOPOIETIC STEM CELL TRANSPLANTATION INTO THE TREATMENT OF ATL HAS ACTIVATED ITS CLINICAL RESEARCH. HOWEVER, THE PROGNOSIS OF ATL REMAINS POOR COMPARED WITH THOSE OF OTHER LEUKEMIAS AND LYMPHOMAS. THUS, SEEMINGLY WE HAVE TO RECONSIDER A NEW STRATEGY OF ATL THERAPY BASED ON ITS UNIQUE CHARACTERISTICS. HTLV-1 INFECTION OF T CELLS RESULTS IN CLONAL PROLIFERATION OF INFECTED CELLS THAT ACCUMULATE GENETIC AND EPIGENETIC ABNORMALITIES BEFORE THE ONSET OF ATL. THEREFORE, THE TREATMENT STRATEGY SHOULD INCLUDE THE PREVENTION OF HTLV-1 INFECTION AND ATL DEVELOPMENT IN ADDITION TO PRECISION MEDICINE BASED ON THE STRATIFICATION OF ATL CASES BY BIOMARKERS THAT DISCRIMINATE CLINICAL STAGES OF ATL. I SUMMARIZE HERE THE RECENT PROGRESS IN ATL RESEARCH FOCUSING ON THE BIOMOLECULAR ABNORMALITIES THAT LEAD TO CLONAL EXPANSION AND MALIGNANT TRANSFORMATION OF HTLV-1-INFECTED T CELLS. APPARENTLY, ONE OF THE BASES FOR THE PREVENTION OF ATL IS TO ESTABLISH A DISEASE ENTITY OF "CHRONIC ACTIVE HTLV-1 INFECTION" THAT DEFINES HIGH-RISK CARRIERS FOR ATL DEVELOPMENT AND ENABLES PREVENTIVE INTERVENTION. 2017 3 4760 29 NOVEL TREATMENTS OF ADULT T CELL LEUKEMIA LYMPHOMA. ADULT T CELL LEUKEMIA-LYMPHOMA (ATL) IS AN AGGRESSIVE MALIGNANCY SECONDARY TO CHRONIC INFECTION WITH THE HUMAN T CELL LEUKEMIA VIRUS TYPE I (HTLV-I) RETROVIRUS. ATL CARRIES A DISMAL PROGNOSIS. ATL CLASSIFIES INTO FOUR SUBTYPES (ACUTE, LYMPHOMA, CHRONIC, AND SMOLDERING) WHICH DISPLAY DIFFERENT CLINICAL FEATURES, PROGNOSIS AND RESPONSE TO THERAPY, HENCE REQUIRING DIFFERENT CLINICAL MANAGEMENT. SMOLDERING AND CHRONIC SUBTYPES RESPOND WELL TO ANTIRETROVIRAL THERAPY USING THE COMBINATION OF ZIDOVUDINE (AZT) AND INTERFERON-ALPHA (IFN) WITH A SIGNIFICANT PROLONGATION OF SURVIVAL. CONVERSELY, THE WATCH AND WAIT STRATEGY OR CHEMOTHERAPY FOR THESE INDOLENT SUBTYPES ALLIES WITH A POOR LONG-TERM OUTCOME. ACUTE ATL IS ASSOCIATED WITH CHEMO-RESISTANCE AND DISMAL PROGNOSIS. LYMPHOMA SUBTYPES RESPOND BETTER TO INTENSIVE CHEMOTHERAPY BUT SURVIVAL REMAINS POOR. ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) RESULTS IN LONG-TERM SURVIVAL IN ROUGHLY ONE THIRD OF TRANSPLANTED PATIENTS BUT ONLY A SMALL PERCENTAGE OF PATIENTS CAN MAKE IT TO TRANSPLANT. OVERALL, CURRENT TREATMENTS OF AGGRESSIVE ATL ARE NOT SATISFACTORY. PROGNOSIS OF REFRACTORY OR RELAPSED PATIENTS IS DISMAL WITH SOME ENCOURAGING RESULTS WHEN USING LENALIDOMIDE OR MOGAMULIZUMAB. TO OVERCOME RESISTANCE AND PREVENT RELAPSE, PRECLINICAL OR PILOT CLINICAL STUDIES USING TARGETED THERAPIES SUCH AS ARSENIC/IFN, MONOCLONAL ANTIBODIES, EPIGENETIC THERAPIES ARE PROMISING BUT WARRANT FURTHER CLINICAL INVESTIGATION. ANTI-ATL VACCINES INCLUDING TAX PEPTIDE-PULSED DENDRITIC CELLS, INDUCED TAX-SPECIFIC CTL RESPONSES IN ATL PATIENTS. FINALLY, BASED ON THE PROGRESS IN UNDERSTANDING THE PATHOPHYSIOLOGY OF ATL, AND THE RISK-ADAPTED TREATMENT APPROACHES TO DIFFERENT ATL SUBTYPES, TREATMENT STRATEGIES OF ATL SHOULD TAKE INTO ACCOUNT THE HOST IMMUNE RESPONSES AND THE HOST MICROENVIRONMENT INCLUDING HTLV-1 INFECTED NON-MALIGNANT CELLS. HEREIN, WE WILL PROVIDE A SUMMARY OF NOVEL TREATMENTS OF ATL IN VITRO, IN VIVO, AND IN EARLY CLINICAL TRIALS. 2020 4 6523 30 TRANSCRIPTIONAL AND EPIGENETIC REGULATORY MECHANISMS AFFECTING HTLV-1 PROVIRUS. HUMAN T-CELL LEUKEMIA VIRUS TYPE 1 (HTLV-1) IS A RETROVIRUS ASSOCIATED WITH HUMAN DISEASES, SUCH AS ADULT T-CELL LEUKEMIA (ATL) AND HTLV-1-ASSOCIATED MYELOPATHY/TROPIC SPASTIC PARAPARESIS (HAM/TSP). AS A RETROVIRUS, ITS LIFE CYCLE INCLUDES A STEP WHERE HTLV-1 IS INTEGRATED INTO THE HOST GENOMIC DNA AND FORMS PROVIRAL DNA. IN THE CHRONIC PHASE OF THE INFECTION, HTLV?1 IS KNOWN TO PROLIFERATE AS A PROVIRUS VIA THE MITOTIC DIVISION OF THE INFECTED HOST CELLS. THERE ARE GENERALLY TENS OF THOUSANDS OF INFECTED CLONES WITHIN AN INFECTED INDIVIDUAL. THEY EXIST NOT ONLY IN PERIPHERAL BLOOD, BUT ALSO IN VARIOUS LYMPHOID ORGANS. VIRAL PROTEINS ENCODED IN HTLV-1 GENOME PLAY A ROLE IN THE PROLIFERATION AND SURVIVAL OF THE INFECTED CELLS. AS IS THE CASE WITH OTHER CHRONIC VIRAL INFECTIONS, HTLV-1 GENE EXPRESSION INDUCES THE ACTIVATION OF THE HOST IMMUNITY AGAINST THE VIRUS. THUS, THE TRANSCRIPTION FROM HTLV-1 PROVIRUS NEEDS TO BE CONTROLLED IN ORDER TO EVADE THE HOST IMMUNE SURVEILLANCE. THERE SHOULD BE A DYNAMIC AND COMPLEX REGULATION IN VIVO, WHERE AN EQUILIBRIUM BETWEEN VIRAL ANTIGEN EXPRESSION AND HOST IMMUNE SURVEILLANCE IS ACHIEVED. THE MECHANISMS REGULATING VIRAL GENE EXPRESSION FROM THE PROVIRUS ARE A KEY TO UNDERSTANDING THE PERSISTENT/LATENT INFECTION WITH HTLV-1 AND ITS PATHOGENESIS. IN THIS ARTICLE, WE WOULD LIKE TO REVIEW OUR CURRENT UNDERSTANDING ON THIS TOPIC. 2016 5 6590 29 TUMOR SUPPRESSOR INACTIVATION IN THE PATHOGENESIS OF ADULT T-CELL LEUKEMIA. TUMOR SUPPRESSOR FUNCTIONS ARE ESSENTIAL TO CONTROL CELLULAR PROLIFERATION, TO ACTIVATE THE APOPTOSIS OR SENESCENCE PATHWAY TO ELIMINATE UNWANTED CELLS, TO LINK DNA DAMAGE SIGNALS TO CELL CYCLE ARREST CHECKPOINTS, TO ACTIVATE APPROPRIATE DNA REPAIR PATHWAYS, AND TO PREVENT THE LOSS OF ADHESION TO INHIBIT INITIATION OF METASTASES. THEREFORE, TUMOR SUPPRESSOR GENES ARE INDISPENSABLE TO MAINTAINING GENETIC AND GENOMIC INTEGRITY. CONSEQUENTLY, INACTIVATION OF TUMOR SUPPRESSORS BY SOMATIC MUTATIONS OR EPIGENETIC MECHANISMS IS FREQUENTLY ASSOCIATED WITH TUMOR INITIATION AND DEVELOPMENT. IN CONTRAST, REACTIVATION OF TUMOR SUPPRESSOR FUNCTIONS CAN EFFECTIVELY REVERSE THE TRANSFORMED PHENOTYPE AND LEAD TO CELL CYCLE ARREST OR DEATH OF CANCEROUS CELLS AND BE USED AS A THERAPEUTIC STRATEGY. ADULT T-CELL LEUKEMIA/LYMPHOMA (ATLL) IS AN AGGRESSIVE LYMPHOPROLIFERATIVE DISEASE ASSOCIATED WITH INFECTION OF CD4 T CELLS BY THE HUMAN T-CELL LEUKEMIA VIRUS TYPE 1 (HTLV-I). HTLV-I-ASSOCIATED T-CELL TRANSFORMATION IS THE RESULT OF A MULTISTEP ONCOGENIC PROCESS IN WHICH THE VIRUS INITIALLY INDUCES CHRONIC T-CELL PROLIFERATION AND ALTERS CELLULAR PATHWAYS RESULTING IN THE ACCUMULATION OF GENETIC DEFECTS AND THE DEREGULATED GROWTH OF VIRALLY INFECTED CELLS. THIS REVIEW WILL FOCUS ON THE CURRENT KNOWLEDGE OF THE GENETIC AND EPIGENETIC MECHANISMS REGULATING THE INACTIVATION OF TUMOR SUPPRESSORS IN THE PATHOGENESIS OF HTLV-I. 2015 6 4695 29 NF-KAPPAB ACTIVATION IN CHRONIC LYMPHOCYTIC LEUKEMIA: A POINT OF CONVERGENCE OF EXTERNAL TRIGGERS AND INTRINSIC LESIONS. THE NUCLEAR FACTOR-KAPPAB (NF-KAPPAB) PATHWAY IS CONSTITUTIVELY ACTIVATED IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) PATIENTS, AND HENCE PLAYS A MAJOR ROLE IN DISEASE DEVELOPMENT AND EVOLUTION. IN CONTRAST TO MANY OTHER MATURE B-CELL LYMPHOMAS, ONLY A FEW RECURRENTLY MUTATED GENES INVOLVED IN CANONICAL OR NON-CANONICAL NF-KAPPAB ACTIVATION HAVE BEEN IDENTIFIED IN CLL (I.E. BIRC3, MYD88 AND NFKBIE MUTATIONS) AND OFTEN AT A LOW FREQUENCY. ON THE OTHER HAND, CLL B CELLS SEEM 'ADDICTED' TO THE TUMOR MICROENVIRONMENT FOR THEIR SURVIVAL AND PROLIFERATION, WHICH IS PRIMARILY MEDIATED BY INTERACTION THROUGH A NUMBER OF CELL SURFACE RECEPTORS, E.G. THE B-CELL RECEPTOR (BCR), TOLL-LIKE RECEPTORS AND CD40, THAT IN TURN ACTIVATE DOWNSTREAM NF-KAPPAB. THE IMPORTANCE OF CELL-EXTRINSIC TRIGGERING FOR CLL PATHOPHYSIOLOGY WAS RECENTLY ALSO HIGHLIGHTED BY THE CLINICAL EFFICACY OF NOVEL DRUGS TARGETING MICROENVIRONMENTAL INTERACTIONS THROUGH THE INHIBITION OF BCR SIGNALING. IN OTHER WORDS, CLL CAN BE CONSIDERED A PROTOTYPE DISEASE FOR STUDYING THE INTRICATE INTERPLAY BETWEEN EXTERNAL TRIGGERS AND INTRINSIC ABERRATIONS AND THEIR COMBINED IMPACT ON DISEASE EVOLUTION. IN THIS REVIEW, WE WILL DISCUSS THE CURRENT UNDERSTANDING OF MECHANISMS UNDERLYING NF-KAPPAB DEREGULATION IN CLL, INCLUDING MICRO-ENVIRONMENTAL, GENETIC AND EPIGENETIC EVENTS, AND SUMMARIZE DATA GENERATED IN MURINE MODELS RESEMBLING HUMAN CLL. FINALLY, WE WILL ALSO DISCUSS DIFFERENT STRATEGIES UNDERTAKEN TO INTERVENE WITH THE NF-KAPPAB PATHWAY AND ITS UPSTREAM MEDIATORS. 2016 7 4728 25 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 8 5475 25 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 9 5477 28 RESTORING THE FUNCTIONAL IMMUNOGENICITY OF CHRONIC LYMPHOCYTIC LEUKEMIA USING EPIGENETIC MODIFIERS. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A MALIGNANCY ARISING FROM IMMUNE CELLS (B-LYMPHOCYTES) ENDOWED WITH INTRINSIC ANTIGEN-PRESENTING CAPABILITIES. SUCH A FUNCTION HOWEVER IS LOST DURING MALIGNANT TRANSFORMATION AND CLL CELLS ARE WELL KNOWN FOR THEIR INABILITY TO PROCESS AND PRESENT ANTIGENS TO THE T-CELL ARM OF THE IMMUNE SYSTEM. INSTEAD, MALIGNANT CLL CELLS ELICIT A VAST ARRAY OF IMMUNE REGULATORY MECHANISMS CONDUCIVE TO T-CELL DYSFUNCTION AND IMMUNOSUPPRESSION. PREVIOUSLY, WE HAVE SHOWN THAT TREATMENT OF CLL CELLS WITH THE DEMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE UNLEASHED TARGET ANTIGEN EXPRESSION. HERE WE SHOW FOR THE FIRST TIME THAT COMBINING TWO EPIGENETIC MODIFIERS, 5-AZA-2'-DEOXYCYTIDINE AND THE HISTONE DEACETYLASE INHIBITOR LAQ824 EFFECTIVELY RESTORES THE IMMUNOGENICITY OF CLL CELL LINES AS WELL AS PRIMARY CELLS OBTAINED FROM CLL PATIENTS. INDEED, SUCH A COMBINATION INDUCES THE EXPRESSION OF NOVEL AND HIGHLY ANTIGENIC CANCER-TESTIS ANTIGENS (CTAS) AND COSTIMULATORY MOLECULES. THESE CHANGES FACILITATE THE FORMATION OF ROBUST SUPRAMOLECULAR ACTIVATION COMPLEXES (SMAC) BETWEEN CLL CELLS AND RESPONDER T-CELLS LEADING TO INTRACELLULAR SIGNALING, LYTIC GRANULE MOBILIZATION, AND POLARIZATION OF FUNCTIONAL AND RELEVANT T-CELL RESPONSES. THIS CASCADE OF T-CELL ACTIVATING EVENTS TRIGGERED BY CLL CELLS WITH RESTORED APC FUNCTION, POINTS TO COMBINED EPIGENETIC MODIFIER TREATMENT AS A POTENTIAL IMMUNOTHERAPEUTIC STRATEGY FOR CLL PATIENTS. 2011 10 1674 23 DRIVER MUTATIONS IN LEUKEMIA PROMOTE DISEASE PATHOGENESIS THROUGH A COMBINATION OF CELL-AUTONOMOUS AND NICHE MODULATION. STUDIES OF PATIENTS WITH ACUTE MYELOID LEUKEMIA (AML) HAVE LED TO THE IDENTIFICATION OF MUTATIONS THAT AFFECT DIFFERENT CELLULAR PATHWAYS. SOME OF THESE HAVE BEEN CLASSIFIED AS PRELEUKEMIC, AND A STEPWISE EVOLUTION PROGRAM WHEREBY CELLS ACQUIRE ADDITIONAL MUTATIONS HAS BEEN PROPOSED IN THE DEVELOPMENT OF AML. HOW THE TIMING OF ACQUISITION OF THESE MUTATIONS AND THEIR IMPACT ON TRANSFORMATION AND THE BONE MARROW (BM) MICROENVIRONMENT OCCURS HAS ONLY RECENTLY BEGUN TO BE INVESTIGATED. WE SHOW THAT CONSTITUTIVE AND EARLY LOSS OF THE EPIGENETIC REGULATOR, TET2, WHEN COMBINED WITH CONSTITUTIVE ACTIVATION OF FLT3, RESULTS IN TRANSFORMATION OF CHRONIC MYELOMONOCYTIC LEUKEMIA-LIKE OR MYELOPROLIFERATIVE NEOPLASM-LIKE PHENOTYPE TO AML, WHICH IS MORE PRONOUNCED IN DOUBLE-MUTANT MICE RELATIVE TO MICE CARRYING MUTATIONS IN SINGLE GENES. FURTHERMORE, WE SHOW THAT IN PRELEUKEMIC AND LEUKEMIC MICE THERE ARE ALTERATIONS IN THE BM NICHE AND SECRETED CYTOKINES, WHICH CREATES A PERMISSIVE ENVIRONMENT FOR THE GROWTH OF MUTATION-BEARING CELLS RELATIVE TO NORMAL CELLS. 2020 11 2928 26 GENERATION OF IPSCS FROM CULTURED HUMAN MALIGNANT CELLS. INDUCED PLURIPOTENT STEM CELLS (IPSCS) CAN BE GENERATED FROM VARIOUS DIFFERENTIATED CELL TYPES BY THE EXPRESSION OF A SET OF DEFINED TRANSCRIPTION FACTORS. SO FAR, IPSCS HAVE BEEN GENERATED FROM PRIMARY CELLS, BUT IT IS UNCLEAR WHETHER HUMAN CANCER CELL LINES CAN BE REPROGRAMMED. HERE WE DESCRIBE THE GENERATION AND CHARACTERIZATION OF IPSCS DERIVED FROM HUMAN CHRONIC MYELOID LEUKEMIA CELLS. WE SHOW THAT, DESPITE THE PRESENCE OF ONCOGENIC MUTATIONS, THESE CELLS ACQUIRED PLURIPOTENCY BY THE EXPRESSION OF 4 TRANSCRIPTION FACTORS AND UNDERWENT DIFFERENTIATION INTO CELL TYPES DERIVED OF ALL 3 GERM LAYERS DURING TERATOMA FORMATION. INTERESTINGLY, ALTHOUGH THE PARENTAL CELL LINE WAS STRICTLY DEPENDENT ON CONTINUOUS SIGNALING OF THE BCR-ABL ONCOGENE, ALSO TERMED ONCOGENE ADDICTION, REPROGRAMMED CELLS LOST THIS DEPENDENCY AND BECAME RESISTANT TO THE BCR-ABL INHIBITOR IMATINIB. THIS FINDING INDICATES THAT THE THERAPEUTIC AGENT IMATINIB TARGETS CELLS IN A SPECIFIC EPIGENETIC DIFFERENTIATED CELL STATE, AND THIS MAY CONTRIBUTE TO ITS INABILITY TO FULLY ERADICATE DISEASE IN CHRONIC MYELOID LEUKEMIA PATIENTS. 2010 12 5589 19 ROLE OF SIRT1 IN THE GROWTH AND REGULATION OF NORMAL HEMATOPOIETIC AND LEUKEMIA STEM CELLS. PURPOSE OF REVIEW: RECENT STUDIES HAVE ENHANCED OUR UNDERSTANDING OF THE ROLE OF THE SIRT1 DEACETYLASE IN REGULATION OF NORMAL HEMATOPOIETIC STEM CELLS (HSCS) AND LEUKEMIA STEM CELLS (LSCS), AND ITS IMPORTANCE IN REGULATING AUTOPHAGY AND EPIGENETIC REPROGRAMMING IN RESPONSE TO METABOLIC ALTERATIONS. RECENT FINDINGS: STUDIES EMPLOYING CONDITIONAL DELETION MOUSE MODELS INDICATE AN IMPORTANT ROLE OF SIRT1 IN MAINTENANCE OF ADULT HSCS UNDER CONDITIONS OF STRESS. SIRT1 IS SIGNIFICANTLY OVEREXPRESSED IN LSC POPULATIONS FROM ACUTE MYELOID LEUKEMIA (AML) PATIENTS WITH THE FLT3-ITD MUTATION, AND MAINTAINS THEIR SURVIVAL, GROWTH AND DRUG RESISTANCE, AS PREVIOUSLY DESCRIBED FOR CHRONIC MYELOGENOUS LEUKEMIA (CML). SIRT1 CAN ALSO ENHANCE LEUKEMIA EVOLUTION AND DRUG RESISTANCE BY PROMOTING GENETIC INSTABILITY. RECENT STUDIES INDICATE AN IMPORTANT ROLE OF SIRT1 IN REGULATING AUTOPHAGY IN RESPONSE TO OXIDATIVE STRESS AND NUTRIENT REQUIREMENTS, AND HAVE ELUCIDATED COMPLEX MECHANISMS BY WHICH SIRT1 REGULATES EPIGENETIC REPROGRAMMING OF STEM CELLS. SUMMARY: SIRT1 INHIBITION HOLDS PROMISE AS A NOVEL APPROACH FOR ABLATION OF LSCS IN CHRONIC PHASE CML OR FLT3-ITD-ASSOCIATED AML. ADDITIONAL STUDIES TO UNDERSTAND THE ROLE OF SIRT1 IN LINKING METABOLIC ALTERATIONS TO GENOMIC STABILITY, AUTOPHAGY AND EPIGENETIC REPROGRAMMING OF STEM CELLS ARE WARRANTED. 2015 13 6773 15 [ADVANCES OF RESEARCH ON DEMETHYLATION THERAPY FOR HEMATOLOGIC MALIGNANCIES]. DNA METHYLATION IS AN IMPORTANT AND REVERSIBLE EPIGENETIC MODIFICATION WHICH REGULATES GENOMIC STABILITY. METHYLATION IS ESSENTIAL FOR MAMMALIAN DEVELOPMENT. GENERALLY, GENE EXPRESSION LEVEL AND DNA METHYLATION ARE NEGATIVE CORRELATION. TRANSCRIPTIONAL SILENCING VIA METHYLATION OF CPG ISLANDS IN THE PROMOTER IS IMPORTANT FOR CELL GROWTH AND DIFFERENTIATION AND PLAYS A KEY ROLE IN TUMORIGENESIS. DEMETHYLATION DRUG CAN MODIFY CHROMATIN AND RESTORE THE ABILITY OF ANTI-ONCOGENE. DEMETHYLATION THERAPY AS A NEW THERAPY MAY TREAT EFFICIENTLY HEMATOLOGICAL MALIGNANCIES WITH RESISTANCE AND RELAPSE. IN THIS REVIEW, DNA METHYLATION MECHANISM, RELATIONSHIP BETWEEN ABERRANT METHYLATION AND HEMATOLOGIC MALIGNANCIES, MECHANISM OF DEMETHYLATION THERAPY, THE ADVANCE OF RESEARCH ON THE DEMETHYLATION THERAPY OF HEMATOLOGICAL MALIGNANCIES, SUCH AS ACUTE AND CHRONIC LEUKEMIA, LYMPHOMA, MYELODYSPLASTIC SYNDROME WERE SUMMARIZED. 2009 14 3622 36 IN VIVO ANTAGONISTIC ROLE OF THE HUMAN T-CELL LEUKEMIA VIRUS TYPE 1 REGULATORY PROTEINS TAX AND HBZ. ADULT T CELL LEUKEMIA (ATL) IS AN AGGRESSIVE MALIGNANCY SECONDARY TO CHRONIC INFECTION BY THE HUMAN T-CELL LEUKEMIA VIRUS TYPE 1 (HTLV-1) INFECTION. TWO VIRAL PROTEINS, TAX AND HBZ, PLAY CENTRAL ROLES IN ATL LEUKEMOGENESIS. TAX EXPRESSION TRANSFORMS T CELLS IN VITRO AND INDUCES ATL-LIKE DISEASE IN MICE. TAX ALSO INDUCES A ROUGH EYE PHENOTYPE AND INCREASES HEMOCYTE COUNT IN DROSOPHILA MELANOGASTER, INDICATIVE OF TRANSFORMATION. AMONG MULTIPLE FUNCTIONS, TAX MODULATES THE EXPRESSION OF THE ENHANCER OF ZESTE HOMOLOG 2 (EZH2), A METHYLTRANSFERASE OF THE POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), LEADING TO H3K27ME3-DEPENDENT REPROGRAMMING OF AROUND HALF OF CELLULAR GENES. HBZ IS A NEGATIVE REGULATOR OF TAX-MEDIATED VIRAL TRANSCRIPTION. HBZ EFFECTS ON EPIGENETIC SIGNATURES ARE UNDEREXPLORED. HERE, WE ESTABLISHED AN HBZ TRANSGENIC FLY MODEL, AND DEMONSTRATED THAT, UNLIKE TAX, WHICH INDUCES NF-KAPPAB ACTIVATION AND ENHANCED PRC2 ACTIVITY CREATING AN ACTIVATION LOOP, HBZ NEITHER INDUCES TRANSFORMATION NOR NF-KAPPAB ACTIVATION IN VIVO. HOWEVER, OVEREXPRESSION OF TAX OR HBZ INCREASES THE PRC2 ACTIVITY AND BOTH PROTEINS DIRECTLY INTERACT WITH PRC2 COMPLEX CORE COMPONENTS. IMPORTANTLY, OVEREXPRESSION OF HBZ IN TAX TRANSGENIC FLIES PREVENTS TAX-INDUCED NF-KAPPAB OR PRC2 ACTIVATION AND TOTALLY RESCUES TAX-INDUCED TRANSFORMATION AND SENESCENCE. OUR RESULTS ESTABLISH THE IN VIVO ANTAGONISTIC EFFECT OF HBZ ON TAX-INDUCED TRANSFORMATION AND CELLULAR EFFECTS. THIS STUDY HELPS UNDERSTANDING LONG-TERM HTLV-1 PERSISTENCE AND CELLULAR TRANSFORMATION AND OPENS PERSPECTIVES FOR NEW THERAPEUTIC STRATEGIES TARGETING THE EPIGENETIC MACHINERY IN ATL. 2021 15 4693 13 NEXT GENERATION OF TARGETED MOLECULES FOR NON-HODGKIN LYMPHOMAS: SMALL-MOLECULE INHIBITORS OF INTRACELLULAR TARGETS AND SIGNALING PATHWAYS. ADVANCES IN OUR UNDERSTANDING OF THE MOLECULAR PATHOGENESIS OF B-CELL LYMPHOMA HAVE GUIDED THE DEVELOPMENT OF TARGETED THERAPIES THAT DISRUPT ABERRANT SIGNALING PATHWAYS IMPORTANT FOR COMMUNICATION WITHIN LYMPHOMA CELLS AND FOR THEIR INTERACTIONS WITH THE TUMOR MICROENVIRONMENT. THIS HAS LED TO UNPRECEDENTED THERAPEUTIC PROGRESS, WITH BIOLOGIC AGENTS THAT HAVE BEGUN TO TRANSFORM THE CARE OF PATIENTS WITH LYMPHOMA AND CHRONIC LYMPHOCYTIC LEUKEMIA. THIS REVIEW DISCUSSES THE MECHANISMS OF ACTION, CLINICAL DEVELOPMENT, AND EMERGING APPLICATIONS OF SMALL-MOLECULE INHIBITORS THAT TARGET B-CELL RECEPTOR SIGNALING PATHWAYS, B-CELL LYMPHOMA-2 INHIBITORS, SELECTIVE INHIBITORS OF NUCLEAR EXPORT, AND EPIGENETIC MODIFIERS. 2016 16 1976 20 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 17 2781 24 EZH2 IN MYELOID MALIGNANCIES. OUR UNDERSTANDING OF THE SIGNIFICANCE OF EPIGENETIC DYSREGULATION IN THE PATHOGENESIS OF MYELOID MALIGNANCIES HAS GREATLY ADVANCED IN THE PAST DECADE. ENHANCER OF ZESTE HOMOLOG 2 (EZH2) IS THE CATALYTIC CORE COMPONENT OF THE POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), WHICH IS RESPONSIBLE FOR GENE SILENCING THROUGH TRIMETHYLATION OF H3K27. EZH2 DYSREGULATION IS HIGHLY TUMORIGENIC AND HAS BEEN OBSERVED IN VARIOUS CANCERS, WITH EZH2 ACTING AS AN ONCOGENE OR A TUMOR-SUPPRESSOR DEPENDING ON CELLULAR CONTEXT. WHILE LOSS-OF-FUNCTION MUTATIONS OF EZH2 FREQUENTLY AFFECT PATIENTS WITH MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASMS, MYELODYSPLASTIC SYNDROME AND MYELOFIBROSIS, CASES OF CHRONIC MYELOID LEUKEMIA (CML) SEEM TO BE LARGELY CHARACTERIZED BY EZH2 OVEREXPRESSION. A VARIETY OF OTHER FACTORS FREQUENTLY ABERRANT IN MYELOID LEUKEMIA CAN AFFECT PRC2 FUNCTION AND DISEASE PATHOGENESIS, INCLUDING ADDITIONAL SEX COMBS LIKE 1 (ASXL1) AND SPLICING GENE MUTATIONS. AS THE GENETIC BACKGROUND OF MYELOID MALIGNANCIES IS LARGELY HETEROGENEOUS, IT IS NOT SURPRISING THAT EZH2 MUTATIONS ACT IN CONJUNCTION WITH OTHER ABERRATIONS. SINCE EZH2 MUTATIONS ARE CONSIDERED TO BE EARLY EVENTS IN DISEASE PATHOGENESIS, THEY ARE OF THERAPEUTIC INTEREST TO RESEARCHERS, THOUGH TARGETING OF EZH2 LOSS-OF-FUNCTION DOES PRESENT UNIQUE CHALLENGES. PRELIMINARY RESEARCH INDICATES THAT COMBINED TYROSINE KINASE INHIBITOR (TKI) AND EZH2 INHIBITOR THERAPY MAY PROVIDE A STRATEGY TO ELIMINATE THE RESIDUAL DISEASE BURDEN IN CML TO ALLOW PATIENTS TO REMAIN IN TREATMENT-FREE REMISSION. 2020 18 3234 21 HEMATOPOIETIC AND CHRONIC MYELOID LEUKEMIA STEM CELLS: MULTI-STABILITY VERSUS LINEAGE RESTRICTION. THERE IS COMPELLING EVIDENCE TO SUPPORT THE VIEW THAT THE CELL-OF-ORIGIN FOR CHRONIC MYELOID LEUKEMIA IS A HEMATOPOIETIC STEM CELL. UNLIKE NORMAL HEMATOPOIETIC STEM CELLS, THE PROGENY OF THE LEUKEMIA STEM CELLS ARE PREDOMINANTLY NEUTROPHILS DURING THE DISEASE CHRONIC PHASE AND THERE IS A MILD ANEMIA. THE HALLMARK ONCOGENE FOR CHRONIC MYELOID LEUKEMIA IS THE BCR-ABLP210 FUSION GENE. VARIOUS STUDIES HAVE EXCLUDED A ROLE FOR BCR-ABLP210 EXPRESSION IN MAINTAINING THE POPULATION OF LEUKEMIA STEM CELLS. STUDIES OF BCR-ABLP210 EXPRESSION IN EMBRYONAL STEM CELLS THAT WERE DIFFERENTIATED INTO HEMATOPOIETIC STEM CELLS AND OF THE EXPRESSION IN TRANSGENIC MICE HAVE REVEALED THAT BCR-ABLP210 IS ABLE TO VEER HEMATOPOIETIC STEM AND PROGENITOR CELLS TOWARDS A MYELOID FATE. FOR THE TRANSGENIC MICE, GLOBAL CHANGES TO THE EPIGENETIC LANDSCAPE WERE OBSERVED. IN CHRONIC MYELOID LEUKEMIA, THE ABILITY OF THE LEUKEMIA STEM CELLS TO CHOOSE FROM THE MANY FATES THAT ARE AVAILABLE TO NORMAL HEMATOPOIETIC STEM CELLS APPEARS TO BE DEREGULATED BY BCR-ABLP210 AND CHANGES TO THE EPIGENOME ARE ALSO IMPORTANT. EVEN SO, WE STILL DO NOT HAVE A PRECISE PICTURE AS TO WHY NEUTROPHILS ARE ABUNDANTLY PRODUCED IN CHRONIC MYELOID LEUKEMIA. 2022 19 2237 17 EPIGENETIC MODIFIERS IN MYELOID MALIGNANCIES: THE ROLE OF HISTONE DEACETYLASE INHIBITORS. MYELOID HEMATOLOGICAL MALIGNANCIES ARE CLONAL BONE MARROW NEOPLASMS, COMPRISING OF ACUTE MYELOID LEUKEMIA (AML), THE MYELODYSPLASTIC SYNDROMES (MDS), CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), THE MYELOPROLIFERATIVE NEOPLASMS (MPN) AND SYSTEMIC MASTOCYTOSIS (SM). THE FIELD OF EPIGENETIC REGULATION OF NORMAL AND MALIGNANT HEMATOPOIESIS IS RAPIDLY GROWING. IN RECENT YEARS, HETEROZYGOUS SOMATIC MUTATIONS IN GENES ENCODING EPIGENETIC REGULATORS HAVE BEEN FOUND IN ALL SUBTYPES OF MYELOID MALIGNANCIES, SUPPORTING THE RATIONALE FOR TREATMENT WITH EPIGENETIC MODIFIERS. HISTONE DEACETYLASE INHIBITORS (HDACI) ARE EPIGENETIC MODIFIERS THAT, IN VITRO, HAVE BEEN SHOWN TO INDUCE GROWTH ARREST, APOPTOTIC OR AUTOPHAGIC CELL DEATH, AND TERMINAL DIFFERENTIATION OF MYELOID TUMOR CELLS. THESE EFFECTS WERE OBSERVED BOTH AT THE BULK TUMOR LEVEL AND IN THE MOST IMMATURE CD34(+)38(-) CELL COMPARTMENTS CONTAINING THE LEUKEMIC STEM CELLS. THUS, THERE IS A STRONG RATIONALE SUPPORTING HDACI THERAPY IN MYELOID MALIGNANCIES. HOWEVER, DESPITE INITIAL PROMISING RESULTS IN PHASE I TRIALS, HDACI IN MONOTHERAPY AS WELL AS IN COMBINATION WITH OTHER DRUGS, HAVE FAILED TO IMPROVE RESPONSES OR SURVIVAL. THIS REVIEW PROVIDES AN OVERVIEW OF THE RATIONALE FOR HDACI IN MYELOID MALIGNANCIES, CLINICAL RESULTS AND SPECULATIONS ON WHY CLINICAL TRIALS HAVE THUS FAR NOT MET THE EXPECTATIONS, AND HOW THIS MAY BE IMPROVED IN THE FUTURE. 2018 20 926 26 CHRONIC INFLAMMATION PATHWAY NF-KAPPAB COOPERATES WITH EPIGENETIC REPROGRAMMING TO DRIVE THE MALIGNANT PROGRESSION OF GLIOBLASTOMA. WITHOUT AN EFFECTIVE STRATEGY FOR TARGETED THERAPY, GLIOBLASTOMA IS STILL INCURABLE WITH A MEDIAN SURVIVAL OF ONLY 15 MONTHS. BOTH CHRONIC INFLAMMATION AND EPIGENETIC REPROGRAMMING ARE HALLMARKS OF CANCER. HOWEVER, THE MECHANISMS AND CONSEQUENCES OF THEIR COOPERATION IN GLIOBLASTOMA REMAIN UNKNOWN. HERE, WE DISCOVER THAT CHRONIC INFLAMMATION GOVERNS H3K27ME3 REPROGRAMMING IN GLIOBLASTOMA THROUGH THE CANONICAL NF-KAPPAB PATHWAY TO TARGET EZH2. BEING A CRUCIAL MEDIATOR OF CHRONIC INFLAMMATION, THE CANONICAL NF-KAPPAB SIGNALLING SPECIFICALLY DIRECTS THE EXPRESSION AND REDISTRIBUTION OF H3K27ME3 BUT NOT H3K4ME3, H3K9ME3 AND H3K36ME3. USING RNA-SEQ SCREENING TO FOCUS ON GENES ENCODING METHYLTRANSFERASES AND DEMETHYLASES OF HISTONE, WE IDENTIFY EZH2 AS A KEY METHYLTRANSFERASE TO CONTROL INFLAMMATION-TRIGGERED EPIGENETIC REPROGRAMMING IN GLIOMAGENESIS. MECHANISTICALLY, NF-KAPPAB SELECTIVELY DRIVES THE EXPRESSION OF EZH2 BY ACTIVATING ITS TRANSCRIPTION, CONSEQUENTLY RESULTING IN A GLOBAL CHANGE IN H3K27ME3 EXPRESSION AND DISTRIBUTION. FURTHERMORE, WE FIND THAT CO-ACTIVATION OF NF-KAPPAB AND EZH2 CONFERS THE POOREST CLINICAL OUTCOME, AND THAT THE RISK FOR GLIOBLASTOMA CAN BE ACCURATELY MOLECULARLY STRATIFIED BY NF-KAPPAB AND EZH2. IT IS NOTABLE THAT NF-KAPPAB CAN POTENTIALLY COOPERATE WITH EZH2 IN MORE THAN ONE WAY, AND MOST IMPORTANTLY, WE DEMONSTRATE A SYNERGISTIC EFFECT OF CANCER CELLS INDUCED BY COMBINATORY INHIBITION OF NF-KAPPAB AND EZH2, WHICH BOTH ARE FREQUENTLY OVER-ACTIVATED IN GLIOBLASTOMA. IN SUMMARY, WE UNCOVER A FUNCTIONAL COOPERATION BETWEEN CHRONIC INFLAMMATION AND EPIGENETIC REPROGRAMMING IN GLIOBLASTOMA, COMBINED TARGETING OF WHICH BY INHIBITORS GUARANTEED IN SAFETY AND AVAILABILITY FURNISHES A POTENT STRATEGY FOR EFFECTIVE TREATMENT OF THIS FATAL DISEASE. 2022