1 1462 141 DISRUPTION OF TET2 PROMOTES THE THERAPEUTIC EFFICACY OF CD19-TARGETED T CELLS. CANCER IMMUNOTHERAPY BASED ON GENETICALLY REDIRECTING T CELLS HAS BEEN USED SUCCESSFULLY TO TREAT B CELL MALIGNANCIES(1-3). IN THIS STRATEGY, THE T CELL GENOME IS MODIFIED BY INTEGRATION OF VIRAL VECTORS OR TRANSPOSONS ENCODING CHIMAERIC ANTIGEN RECEPTORS (CARS) THAT DIRECT TUMOUR CELL KILLING. HOWEVER, THIS APPROACH IS OFTEN LIMITED BY THE EXTENT OF EXPANSION AND PERSISTENCE OF CAR T CELLS(4,5). HERE WE REPORT MECHANISTIC INSIGHTS FROM STUDIES OF A PATIENT WITH CHRONIC LYMPHOCYTIC LEUKAEMIA TREATED WITH CAR T CELLS TARGETING THE CD19 PROTEIN. FOLLOWING INFUSION OF CAR T CELLS, ANTI-TUMOUR ACTIVITY WAS EVIDENT IN THE PERIPHERAL BLOOD, LYMPH NODES AND BONE MARROW; THIS ACTIVITY WAS ACCOMPANIED BY COMPLETE REMISSION. UNEXPECTEDLY, AT THE PEAK OF THE RESPONSE, 94% OF CAR T CELLS ORIGINATED FROM A SINGLE CLONE IN WHICH LENTIVIRAL VECTOR-MEDIATED INSERTION OF THE CAR TRANSGENE DISRUPTED THE METHYLCYTOSINE DIOXYGENASE TET2 GENE. FURTHER ANALYSIS REVEALED A HYPOMORPHIC MUTATION IN THIS PATIENT'S SECOND TET2 ALLELE. TET2-DISRUPTED CAR T CELLS EXHIBITED AN EPIGENETIC PROFILE CONSISTENT WITH ALTERED T CELL DIFFERENTIATION AND, AT THE PEAK OF EXPANSION, DISPLAYED A CENTRAL MEMORY PHENOTYPE. EXPERIMENTAL KNOCKDOWN OF TET2 RECAPITULATED THE POTENCY-ENHANCING EFFECT OF TET2 DYSFUNCTION IN THIS PATIENT'S CAR T CELLS. THESE FINDINGS SUGGEST THAT THE PROGENY OF A SINGLE CAR T CELL INDUCED LEUKAEMIA REMISSION AND THAT TET2 MODIFICATION MAY BE USEFUL FOR IMPROVING IMMUNOTHERAPIES. 2018 2 1313 43 DELETING DNMT3A IN CAR T CELLS PREVENTS EXHAUSTION AND ENHANCES ANTITUMOR ACTIVITY. CHIMERIC ANTIGEN RECEPTOR (CAR) T CELL THERAPY IS REVOLUTIONIZING CANCER IMMUNOTHERAPY FOR PATIENTS WITH B CELL MALIGNANCIES AND IS NOW BEING DEVELOPED FOR SOLID TUMORS AND CHRONIC VIRAL INFECTIONS. ALTHOUGH CLINICAL TRIALS HAVE DEMONSTRATED THE CURATIVE POTENTIAL OF CAR T CELL THERAPY, A SUBSTANTIAL AND WELL-ESTABLISHED LIMITATION IS THE HEIGHTENED CONTRACTION AND TRANSIENT PERSISTENCE OF CAR T CELLS DURING PROLONGED ANTIGEN EXPOSURE. THE UNDERLYING MECHANISM(S) FOR THIS DYSFUNCTIONAL STATE, OFTEN TERMED CAR T CELL EXHAUSTION, REMAINS POORLY DEFINED. HERE, WE REPORT THAT EXHAUSTION OF HUMAN CAR T CELLS OCCURS THROUGH AN EPIGENETIC REPRESSION OF THE T CELL'S MULTIPOTENT DEVELOPMENTAL POTENTIAL. DELETION OF THE DE NOVO DNA METHYLTRANSFERASE 3 ALPHA (DNMT3A) IN T CELLS EXPRESSING FIRST- OR SECOND-GENERATION CARS UNIVERSALLY PRESERVED THE CELLS' ABILITY TO PROLIFERATE AND MOUNT AN ANTITUMOR RESPONSE DURING PROLONGED TUMOR EXPOSURE. THE INCREASED FUNCTIONALITY OF THE EXHAUSTION-RESISTANT DNMT3A KNOCKOUT CAR T CELLS WAS COUPLED TO AN UP-REGULATION OF INTERLEUKIN-10, AND GENOME-WIDE DNA METHYLATION PROFILING DEFINED AN ATLAS OF GENES TARGETED FOR EPIGENETIC SILENCING. THIS ATLAS PROVIDES A MOLECULAR DEFINITION OF CAR T CELL EXHAUSTION, WHICH INCLUDES MANY TRANSCRIPTIONAL REGULATORS THAT LIMIT THE "STEMNESS" OF IMMUNE CELLS, INCLUDING CD28, CCR7, TCF7, AND LEF1. LAST, WE DEMONSTRATE THAT THIS EPIGENETICALLY REGULATED MULTIPOTENCY PROGRAM IS FIRMLY COUPLED TO THE CLINICAL OUTCOME OF PRIOR CAR T CELL THERAPIES. THESE DATA DOCUMENT THE CRITICAL ROLE EPIGENETIC MECHANISMS PLAY IN LIMITING THE FATE POTENTIAL OF HUMAN T CELLS AND PROVIDE A ROAD MAP FOR LEVERAGING THIS INFORMATION FOR IMPROVING CAR T CELL EFFICACY. 2021 3 942 30 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 4 590 45 BET BROMODOMAIN PROTEIN INHIBITION REVERSES CHIMERIC ANTIGEN RECEPTOR EXTINCTION AND REINVIGORATES EXHAUSTED T CELLS IN CHRONIC LYMPHOCYTIC LEUKEMIA. CHIMERIC ANTIGEN RECEPTOR (CAR) T CELLS HAVE INDUCED REMARKABLE ANTITUMOR RESPONSES IN B CELL MALIGNANCIES. SOME PATIENTS DO NOT RESPOND BECAUSE OF T CELL DEFICIENCIES THAT HAMPER THE EXPANSION, PERSISTENCE, AND EFFECTOR FUNCTION OF THESE CELLS. WE USED LONGITUDINAL IMMUNE PROFILING TO IDENTIFY PHENOTYPIC AND PHARMACODYNAMIC CHANGES IN CD19-DIRECTED CAR T CELLS IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). CAR EXPRESSION MAINTENANCE WAS ALSO INVESTIGATED BECAUSE THIS CAN AFFECT RESPONSE DURABILITY. CAR T CELL FAILURE WAS ACCOMPANIED BY PREEXISTING T CELL-INTRINSIC DEFECTS OR DYSFUNCTION ACQUIRED AFTER INFUSION. IN A SMALL SUBSET OF PATIENTS, CAR SILENCING WAS OBSERVED COINCIDENT WITH LEUKEMIA RELAPSE. USING A SMALL MOLECULE INHIBITOR, WE DEMONSTRATED THAT THE BROMODOMAIN AND EXTRA-TERMINAL (BET) FAMILY OF CHROMATIN ADAPTERS PLAYS A ROLE IN DOWNREGULATING CAR EXPRESSION. BET PROTEIN BLOCKADE ALSO AMELIORATED CAR T CELL EXHAUSTION AS MANIFESTED BY INHIBITORY RECEPTOR REDUCTION, ENHANCED METABOLIC FITNESS, INCREASED PROLIFERATIVE CAPACITY, AND ENRICHED TRANSCRIPTOMIC SIGNATURES OF T CELL REINVIGORATION. BET INHIBITION DECREASED LEVELS OF THE TET2 METHYLCYTOSINE DIOXYGENASE, AND FORCED EXPRESSION OF THE TET2 CATALYTIC DOMAIN ELIMINATED THE POTENCY-ENHANCING EFFECTS OF BET PROTEIN TARGETING IN CAR T CELLS, PROVIDING A MECHANISM LINKING BET PROTEINS AND T CELL DYSFUNCTION. THUS, MODULATING BET EPIGENETIC READERS MAY IMPROVE THE EFFICACY OF CELL-BASED IMMUNOTHERAPIES. 2021 5 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 6 2025 27 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 1976 25 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 8 1542 34 DNA METHYLATION IN HAEMATOLOGICAL MALIGNANCIES: THE ROLE OF DECITABINE. NORMAL CELL DEVELOPMENT AND FUNCTION IS DEPENDENT UPON CONTROLLED GENE EXPRESSION. DNA METHYLATION IS AN EPIGENETIC MODIFICATION THAT CAN PLAY AN IMPORTANT ROLE IN THE CONTROL OF GENE EXPRESSION. DNA METHYLATION AT CYTOSINE RESIDUES IN GENE PROMOTER CPG SEQUENCES IS KNOWN TO INHIBIT GENE TRANSCRIPTION. INAPPROPRIATE INHIBITION OF THE TRANSCRIPTION OF TUMOUR SUPPRESSOR GENES, GENES THAT INHIBIT ANGIOGENESIS AND METASTASIS AND GENES INVOLVED IN DNA REPAIR BY UNCONTROLLED METHYLATION, CAN LEAD TO UNREGULATED GROWTH AND PROLIFERATION OF A CELL AND CARCINOGENESIS. PROMOTER HYPERMETHYLATION AFFECTING THE P16 GENE, RESULTING IN GENE SILENCING, HAS BEEN SHOWN TO OCCUR IN MANY HUMAN SOLID TUMOURS AND A 'HYPERMETHYLATION PROFILE' IN SOME LEUKAEMIAS HAS BEEN DEFINED. THE MOLECULAR MECHANISMS BY WHICH ABERRANT DNA METHYLATION TAKES PLACE DURING CARCINOGENESIS ARE STILL NOT CLEAR. HOWEVER, THE LARGE NUMBER OF TARGET GENES (INVOLVED IN TUMORIGENESIS) THAT ARE SILENCED BY ABERRANT METHYLATION SUGGESTS THAT INHIBITION OF THIS PROCESS MAY HAVE POTENTIAL AS CANCER THERAPY. DECITABINE (NSC-127716, DACOGEN; SUPERGEN) IS A POTENT AND SPECIFIC HYPOMETHYLATING AGENT AND AN INHIBITOR OF THE DNA METHYLTRANSFERASE ACTIVITY THAT MEDIATES DNA METHYLATION. DECITABINE HAS BEEN SHOWN TO HAVE A BROAD RANGE OF ANTINEOPLASTIC ACTIVITY IN PRECLINICAL STUDIES. THIS AGENT HAS EXHIBITED SIGNIFICANT ACTIVITY IN THE TREATMENT OF PATIENTS WITH MYELODYSPLASTIC SYNDROME, CHRONIC MYELOID LEUKAEMIA AND ACUTE MYELOID LEUKAEMIA, ALTHOUGH CLINICAL PHASE I AND II STUDIES WITH SOLID TUMOURS HAVE NOT BEEN VERY PROMISING. PHASE II AND III STUDIES ARE CURRENTLY ONGOING TO EVALUATE DECITABINE, BOTH ALONE AND IN COMBINATION, IN VARIOUS STAGES OF THESE HAEMATOLOGICAL MALIGNANCIES. 2003 9 851 26 CHIP-SEQ ANALYSIS OF HUMAN CHRONIC MYELOID LEUKEMIA CELLS. MANY TRANSCRIPTION FACTORS, CHROMATIN-ASSOCIATED PROTEINS AND REGULATORY DNA ELEMENTS ARE GENETICALLY AND/OR EPIGENETICALLY ALTERED IN CANCER, INCLUDING CHRONIC MYELOID LEUKEMIA (CML). THIS LEADS TO DEREGULATION OF TRANSCRIPTION THAT IS OFTEN CAUSALLY LINKED TO THE TUMORIGENIC STATE. CHROMATIN-IMMUNOPRECIPITATION COUPLED WITH MASSIVELY PARALLEL DNA SEQUENCING (CHIP-SEQ) IS THE KEY TECHNOLOGY TO STUDY TRANSCRIPTION AS IT ALLOWS IN VIVO WHOLE-GENOME MAPPING OF EPIGENETIC MODIFICATIONS AND INTERACTIONS OF PROTEINS WITH DNA OR CHROMATIN. HOWEVER, NUMEROUS DNA/CHROMATIN-BINDING PROTEINS, INCLUDING EZH2, REMAIN DIFFICULT TO "CHIP," THUS YIELDING GENOME-WIDE BINDING MAPS OF ONLY SUBOPTIMAL QUALITY. HERE, WE DESCRIBE A CHIP-SEQ PROTOCOL OPTIMIZED FOR HIGH-QUALITY PROTEIN-GENOME BINDING MAPS THAT HAVE PROVEN ESPECIALLY USEFUL FOR STUDYING DIFFICULT TO 'CHIP' TRANSCRIPTION REGULATORY FACTORS IN CHRONIC MYELOID LEUKEMIA (CML) AND RELATED MALIGNANCIES. 2016 10 2146 27 EPIGENETIC MANIPULATION RESTORES FUNCTIONS OF DEFECTIVE CD8(+) T CELLS FROM CHRONIC VIRAL INFECTION. FUNCTIONAL EXHAUSTION OF ANTIGEN-SPECIFIC T CELLS IS A DEFINING CHARACTERISTIC OF MANY CHRONIC INFECTIONS, BUT THE UNDERLYING MECHANISMS OF T CELL DYSFUNCTION ARE NOT WELL UNDERSTOOD. EPIGENETICS PLAYS AN IMPORTANT ROLE IN THE CONTROL OF T CELL DEVELOPMENT, DIFFERENTIATION, AND FUNCTION. TO EXAMINE IF EPIGENETICS ALSO PLAYS A ROLE IN T CELL EXHAUSTION, WE ANALYZED CHROMATIN REMODELING IN CD8(+) T CELLS FROM MICE WITH CHRONIC LYMPHOCYTIC CHORIOMENINGITIS VIRUS INFECTION. WE OBSERVED DOWNREGULATION OF DIACETYLATED HISTONE H3 IN BOTH VIRUS-SPECIFIC AND TOTAL CD8(+) T CELLS, AND FUNCTIONAL DEFECTS NOT ONLY IN VIRUS-SPECIFIC CD8(+) T CELLS BUT ALSO WITHIN THE TOTAL CD8(+) T CELL POPULATION. IN VITRO TREATMENT OF THESE EXHAUSTED CD8(+) T CELLS WITH HISTONE DEACETYLASE INHIBITORS RESTORED DIACETYLATED HISTONE H3 LEVELS, AND IMPROVED THEIR IMMUNE FUNCTIONS. UPON ADOPTIVE TRANSFER, THESE TREATED CD8(+) T CELLS DEVELOPED INTO FUNCTIONAL MEMORY T CELLS IN VIVO THAT ENHANCED PROTECTIVE IMMUNITY. THESE RESULTS DEFINE A ROLE OF EPIGENETICS IN T CELL EXHAUSTION AND SUGGEST EPIGENETIC MANIPULATION AS A NOVEL MOLECULAR THERAPY TO RESTORE IMMUNE FUNCTIONS. 2014 11 5982 34 TET2 REGULATES IMMUNE TOLERANCE IN CHRONICALLY ACTIVATED MAST CELLS. MUTATION OF THE TET2 DNA-HYDROXYMETHYLASE HAS BEEN ASSOCIATED WITH A NUMBER OF IMMUNE PATHOLOGIES. THE DISPARITY IN PHENOTYPE AND CLINICAL PRESENTATION AMONG THESE PATHOLOGIES LEADS TO QUESTIONS REGARDING THE ROLE OF TET2 MUTATION IN PROMOTING DISEASE EVOLUTION IN DIFFERENT IMMUNE CELL TYPES. HERE WE SHOW THAT, IN PRIMARY MAST CELLS, TET2 EXPRESSION IS INDUCED IN RESPONSE TO CHRONIC AND ACUTE ACTIVATION SIGNALS. IN TET2-DEFICIENT MAST CELLS, CHRONIC ACTIVATION VIA THE ONCOGENIC KITD816V ALLELE ASSOCIATED WITH MASTOCYTOSIS, SELECTS FOR A SPECIFIC EPIGENETIC SIGNATURE CHARACTERIZED BY HYPERMETHYLATED DNA REGIONS (HMR) AT IMMUNE RESPONSE GENES. H3K27AC AND TRANSCRIPTION FACTOR BINDING IS CONSISTENT WITH PRIMING OR MORE OPEN CHROMATIN AT BOTH HMR AND NON-HMR IN PROXIMITY TO IMMUNE GENES IN THESE CELLS, AND THIS SIGNATURE COINCIDES WITH INCREASED PATHOLOGICAL INFLAMMATION SIGNALS. HMR ARE ALSO ASSOCIATED WITH A SUBSET OF IMMUNE GENES THAT ARE DIRECT TARGETS OF TET2 AND REPRESSED IN TET2-DEFICIENT CELLS. REPRESSION OF THESE GENES RESULTS IN IMMUNE TOLERANCE TO ACUTE STIMULATION THAT CAN BE RESCUED WITH VITAMIN C TREATMENT OR REITERATED WITH A TET INHIBITOR. OVERALL, OUR DATA SUPPORT A MODEL WHERE TET2 PLAYS A DIRECT ROLE IN PREVENTING IMMUNE TOLERANCE IN CHRONICALLY ACTIVATED MAST CELLS, SUPPORTING TET2 AS A VIABLE TARGET TO REPROGRAM THE INNATE IMMUNE RESPONSE FOR INNOVATIVE THERAPIES. 2022 12 1533 29 DNA METHYLATION DYNAMICS DURING B CELL MATURATION UNDERLIE A CONTINUUM OF DISEASE PHENOTYPES IN CHRONIC LYMPHOCYTIC LEUKEMIA. CHARTING DIFFERENCES BETWEEN TUMORS AND NORMAL TISSUE IS A MAINSTAY OF CANCER RESEARCH. HOWEVER, CLONAL TUMOR EXPANSION FROM COMPLEX NORMAL TISSUE ARCHITECTURES POTENTIALLY OBSCURES CANCER-SPECIFIC EVENTS, INCLUDING DIVERGENT EPIGENETIC PATTERNS. USING WHOLE-GENOME BISULFITE SEQUENCING OF NORMAL B CELL SUBSETS, WE OBSERVED BROAD EPIGENETIC PROGRAMMING OF SELECTIVE TRANSCRIPTION FACTOR BINDING SITES COINCIDENT WITH THE DEGREE OF B CELL MATURATION. BY COMPARING NORMAL B CELLS TO MALIGNANT B CELLS FROM 268 PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), WE SHOWED THAT TUMORS DERIVE LARGELY FROM A CONTINUUM OF MATURATION STATES REFLECTED IN NORMAL DEVELOPMENTAL STAGES. EPIGENETIC MATURATION IN CLL WAS ASSOCIATED WITH AN INDOLENT GENE EXPRESSION PATTERN AND INCREASINGLY FAVORABLE CLINICAL OUTCOMES. WE FURTHER UNCOVERED THAT MOST PREVIOUSLY REPORTED TUMOR-SPECIFIC METHYLATION EVENTS ARE NORMALLY PRESENT IN NON-MALIGNANT B CELLS. INSTEAD, WE IDENTIFIED A POTENTIAL PATHOGENIC ROLE FOR TRANSCRIPTION FACTOR DYSREGULATION IN CLL, WHERE EXCESS PROGRAMMING BY EGR AND NFAT WITH REDUCED EBF AND AP-1 PROGRAMMING IMBALANCES THE NORMAL B CELL EPIGENETIC PROGRAM. 2016 13 5223 41 PRIMARY MURINE CD4+ T CELLS FAIL TO ACQUIRE THE ABILITY TO PRODUCE EFFECTOR CYTOKINES WHEN ACTIVE RAS IS PRESENT DURING TH1/TH2 DIFFERENTIATION. CONSTITUTIVE RAS SIGNALING HAS BEEN SHOWN TO AUGMENT IL-2 PRODUCTION, REVERSE ANERGY, AND FUNCTIONALLY REPLACE MANY ASPECTS OF CD28 CO-STIMULATION IN CD4+ T CELLS. THESE DATA RAISE THE POSSIBILITY THAT INTRODUCTION OF ACTIVE RAS INTO PRIMARY T CELLS MIGHT RESULT IN IMPROVED FUNCTIONALITY IN PATHOLOGIC SITUATIONS OF T CELL DYSFUNCTION, SUCH AS CANCER OR CHRONIC VIRAL INFECTION. TO TEST THE BIOLOGIC EFFECTS OF ACTIVE RAS IN PRIMARY T CELLS, CD4+ T CELLS FROM COXSACKIE-ADENOVIRUS RECEPTOR TRANSGENIC MICE WERE TRANSDUCED WITH AN ADENOVIRUS ENCODING ACTIVE RAS. AS EXPECTED, ACTIVE RAS AUGMENTED IL-2 PRODUCTION IN NAIVE CD4+ T CELLS. HOWEVER, WHEN CELLS WERE CULTURED FOR 4 DAYS UNDER CONDITIONS TO PROMOTE EFFECTOR CELL DIFFERENTIATION, ACTIVE RAS INHIBITED THE ABILITY OF CD4+ T CELLS TO ACQUIRE A TH1 OR TH2 EFFECTOR CYTOKINE PROFILE. THIS DIFFERENTIATION DEFECT WAS NOT DUE TO DEFICIENT STAT4 OR STAT6 ACTIVATION BY IL-12 OR IL-4, RESPECTIVELY, NOR WAS IT ASSOCIATED WITH DEFICIENT INDUCTION OF T-BET AND GATA-3 EXPRESSION. IMPAIRED EFFECTOR CYTOKINE PRODUCTION IN ACTIVE RAS-TRANSDUCED CELLS WAS ASSOCIATED WITH DEFICIENT DEMETHYLATION OF THE IL-4 GENE LOCUS. OUR RESULTS INDICATE THAT, DESPITE AUGMENTING ACUTE ACTIVATION OF NAIVE T CELLS, CONSTITUTIVE RAS SIGNALING INHIBITS THE ABILITY OF CD4+ T CELLS TO PROPERLY DIFFERENTIATE INTO TH1/TH2 EFFECTOR CYTOKINE-PRODUCING CELLS, IN PART BY INTERFERING WITH EPIGENETIC MODIFICATION OF EFFECTOR GENE LOCI. ALTERNATIVE STRATEGIES TO POTENTIATE RAS PATHWAY SIGNALING IN T CELLS IN A MORE REGULATED FASHION SHOULD BE CONSIDERED AS A THERAPEUTIC APPROACH TO IMPROVE IMMUNE RESPONSES IN VIVO. 2014 14 4728 28 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 15 2764 30 EXPRESSION PATTERN, REGULATION, AND CLINICAL SIGNIFICANCE OF TOX IN BREAST CANCER. THYMOCYTE SELECTION-ASSOCIATED HIGH MOBILITY GROUP BOX PROTEIN (TOX) IS A TRANSCRIPTION FACTOR IMPLICATED IN THE REGULATION OF T CELL EXHAUSTION DURING CHRONIC INFECTION AND CANCER. WHILE TOX IS BEING TARGETED FOR CANCER IMMUNOTHERAPY, LIMITED INFORMATION IS AVAILABLE ABOUT ITS SIGNIFICANCE IN BREAST CANCER AND OTHER SOLID TUMORS. WE PERFORMED A COMPREHENSIVE ANALYSIS OF TOX GENE EXPRESSION, ITS EPIGENETIC REGULATION, PROTEIN LOCALIZATION, RELATION TO TUMOR INFILTRATING IMMUNE CELL COMPOSITION, AND PROGNOSTIC SIGNIFICANCE IN BREAST CANCER USING PUBLICLY AVAILABLE DATASETS. OUR RESULTS SUGGEST AN INVERSE CORRELATION BETWEEN TOX EXPRESSION AND DNA METHYLATION IN TUMOR CELLS. HOWEVER, ITS EXPRESSION IS ELEVATED IN TUMOR INFILTRATING IMMUNE CELLS (TIICS), WHICH MAY COMPENSATES FOR THE TOTAL TOX LEVELS IN THE TUMOR AS A WHOLE. FURTHERMORE, HIGHER TOX LEVELS IN TUMORS ARE ASSOCIATED WITH T CELL EXHAUSTION SIGNATURES ALONG WITH PRESENCE OF ACTIVE INFLAMMATORY RESPONSE, INCLUDING ELEVATED LEVELS OF T CELL EFFECTOR CYTOKINES. SURVIVAL ANALYSIS ALSO CONFIRMED THAT HIGHER EXPRESSION OF TOX IS ASSOCIATED WITH BETTER PROGNOSIS IN BREAST CANCER. THEREFORE, EXPRESSION OF TOX MAY SERVE AS A NOVEL PROGNOSTIC MARKER FOR THIS MALIGNANCY. 2021 16 2055 23 EPIGENETIC CONTROL DURING LYMPHOID DEVELOPMENT AND IMMUNE RESPONSES: ABERRANT REGULATION, VIRUSES, AND CANCER. METHYLATION OF CYTOSINES CONTROLS A NUMBER OF BIOLOGIC PROCESSES SUCH AS IMPRINTING AND X CHROMOSOMAL INACTIVATION. DNA HYPERMETHYLATION IS CLOSELY ASSOCIATED WITH TRANSCRIPTIONAL SILENCING, WHILE DNA HYPOMETHYLATION IS ASSOCIATED WITH TRANSCRIPTIONAL ACTIVATION. HYPOACETYLATION OF HISTONES LEADS TO COMPACT CHROMATIN WITH REDUCED ACCESSIBILITY TO THE TRANSCRIPTIONAL MACHINERY. METHYL-CPG BINDING PROTEINS CAN RECRUIT COREPRESSORS AND HISTONE DEACETYLASES; THUS, THE INTERPLAY BETWEEN THESE EPIGENETIC MECHANISMS REGULATES GENE ACTIVATION. METHYLATION HAS BEEN IMPLICATED AS AN IMPORTANT MECHANISM DURING IMMUNE DEVELOPMENT, CONTROLLING VDJ RECOMBINATION, LINEAGE-SPECIFIC EXPRESSION OF CELL SURFACE ANTIGENS, AND TRANSCRIPTIONAL REGULATION OF CYTOKINE GENES DURING IMMUNE RESPONSES. ABERRATIONS IN EPIGENETIC MACHINERY, EITHER BY GENETIC MUTATIONS OR BY SOMATIC CHANGES SUCH AS VIRAL INFECTIONS, ARE ASSOCIATED WITH EARLY ALTERATIONS IN CHRONIC DISEASES SUCH AS IMMUNODEFICIENCY AND CANCER. 2003 17 1319 33 DEMETHYLATION OF THE PD-1 PROMOTER IS IMPRINTED DURING THE EFFECTOR PHASE OF CD8 T CELL EXHAUSTION. PD-1 IS AN INHIBITORY RECEPTOR THAT HAS A MAJOR ROLE IN T CELL DYSFUNCTION DURING CHRONIC INFECTIONS AND CANCER. WHILE DEMETHYLATION OF THE PD-1 PROMOTER DNA IS OBSERVED IN EXHAUSTED T CELLS ISOLATED FROM CHRONICALLY INFECTED INDIVIDUALS, LITTLE IS KNOWN ABOUT WHEN THIS STABLE DEMETHYLATION OF PD-1 PROMOTER DNA IS PROGRAMMED DURING THE COURSE OF A CHRONIC INFECTION. TO ASSESS IF PD-1 PROMOTER DNA DEMETHYLATION IS IMPACTED BY PROLONGED STIMULATION DURING EFFECTOR PHASE OF CHRONIC INFECTION, WE ADOPTIVELY TRANSFERRED VIRUS-SPECIFIC DAY 8 EFFECTOR CD8 T CELLS FROM MICE INFECTED WITH LYMPHOCYTIC CHORIOMENINGITIS VIRUS (LCMV) CLONE 13 INTO RECIPIENT MICE THAT HAD CLEARED AN ACUTE INFECTION. WE OBSERVED THAT LCMV-SPECIFIC CD8 T CELLS FROM CHRONICALLY INFECTED MICE MAINTAINED THEIR SURFACE EXPRESSION OF PD-1 EVEN AFTER TRANSFER INTO ACUTE IMMUNE MICE UNTIL DAY 45 POSTTRANSFER. INTERESTINGLY, THE PD-1 TRANSCRIPTIONAL REGULATORY REGION CONTINUED TO REMAIN UNMETHYLATED IN THESE DONOR CD8 T CELLS GENERATED FROM A CHRONIC INFECTION. THE OBSERVED MAINTENANCE OF PD-1 SURFACE EXPRESSION AND THE DEMETHYLATED PD-1 PROMOTER WERE NOT A RESULT OF RESIDUAL ANTIGEN IN THE RECIPIENT MICE, BECAUSE SIMILAR RESULTS WERE SEEN WHEN CHRONIC INFECTION-INDUCED EFFECTOR CELLS WERE TRANSFERRED INTO MICE INFECTED WITH A VARIANT STRAIN OF LCMV (LCMV V35A) BEARING A MUTATION IN THE COGNATE MAJOR HISTOCOMPATIBILITY COMPLEX CLASS I (MHC-I) EPITOPE THAT IS RECOGNIZED BY THE DONOR CD8 T CELLS. IMPORTANTLY, THE MAINTENANCE OF PD-1 PROMOTER DEMETHYLATION IN MEMORY CD8 T CELLS WAS COUPLED WITH IMPAIRED CLONAL EXPANSION AND HIGHER PD-1 RE-EXPRESSION UPON SECONDARY CHALLENGE. THESE DATA SHOW THAT THE IMPRINTING OF THE EPIGENETIC PROGRAM OF THE INHIBITORY RECEPTOR PD-1 OCCURS DURING THE EFFECTOR PHASE OF CHRONIC VIRAL INFECTION. IMPORTANCE: SINCE PD-1 IS A MAJOR INHIBITORY RECEPTOR REGULATING T CELL DYSFUNCTION DURING CHRONIC VIRAL INFECTION AND CANCERS, A BETTER UNDERSTANDING OF THE MECHANISMS THAT REGULATE PD-1 EXPRESSION IS IMPORTANT. IN THIS WORK, WE DEMONSTRATE THAT THE PD-1 EPIGENETIC PROGRAM IN ANTIGEN-SPECIFIC CD8 T CELLS IS FIXED DURING THE PRIMING PHASE OF CHRONIC INFECTION. 2016 18 6773 22 [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 19 358 35 ALTERNATIVE SPLICING IN CHRONIC MYELOID LEUKEMIA (CML): A NOVEL THERAPEUTIC TARGET? ALTHOUGH THE IMATINIB BASED THERAPY OF CHRONIC MYELOID LEUKEMIA (CML) REPRESENTS A TRIUMPH OF MEDICINE, NOT ALL PATIENTS WITH CML BENEFIT FROM THIS DRUG DUE TO THE DEVELOPMENT OF RESISTANCE AND INTOLERANCE. THE INTERRUPTION OF IMATINIB TREATMENT IS OFTEN FOLLOWED BY CLINICAL RELAPSE, SUGGESTING A FAILURE IN THE KILLING OF RESIDUAL LEUKAEMIC STEM CELLS. THERE IS NEED TO IDENTIFY ALTERNATIVE SELECTIVE MOLECULAR TARGETS FOR THIS DISEASE AND DEVELOP MORE EFFECTIVE THERAPEUTIC APPROACHES. ALTERNATIVE PRE-MRNA SPLICING (AS) IS AN EPIGENETIC PROCESS THAT GREATLY DIVERSIFIES THE REPERTOIRE OF THE TRANSCRIPTOME. AS ORCHESTRATES INTERACTIONS BETWEEN VARIOUS TYPES OF PROTEINS AND BETWEEN PROTEINS AND NUCLEIC ACIDS. CHANGES CAUSED BY INDIVIDUAL SPLICING EVENTS IN THE CELLS ARE SMALL, HOWEVER, "SPLICING PROGRAMS" TYPICALLY REACT TO THESE INDIVIDUAL CHANGES WITH CONSIDERABLE EFFECTS IN CELL PROLIFERATION, CELL SURVIVAL, AND APOPTOSIS. CURRENT EVIDENCE SUGGESTS A PIVOTAL ROLE OF AS IN LEUKEMIAS, PARTICULARLY IN MYELODISPLASTIC SYNDROME (MDS) AND CHRONIC LYMPHOCYTE LEUKEMIA (CLL). FROM THESE STUDIES AND STUDIES IN OTHER MALIGNANCES, IT IS CLEAR THAT SPLICING ABNORMALITIES PLAY A SIGNIFICANT ROLE IN MALIGNANT TRANSFORMATION. EVALUATION OF AS EVENTS IN CML CAN BE USED TO IDENTIFY NOVEL DISEASE MARKERS AND DRUGSENSITIVE TARGETS TO OVERCOME THE LIMITS OF THE SMALL MOLECULE INHIBITORS CURRENTLY USED FOR TREATING PATIENTS WITH CML. THE USE OF ABERRANT SPLICE VARIANTS AS DISEASE MARKERS HAS BEEN REPORTED, HOWEVER, LITTLE IS KNOWN ABOUT THE USE OF SPLICING ABNORMALITIES AS DRUG TARGETS IN CML. HEREIN WE DISCUSS POTENTIAL THERAPEUTIC APPROACHES THAT CAN BE USED TO TARGET SPLICING ABNORMALITIES IN CML. 2013 20 2056 27 EPIGENETIC CONTROL OF CD8(+) T CELL DIFFERENTIATION. UPON STIMULATION, SMALL NUMBERS OF NAIVE CD8(+) T CELLS PROLIFERATE AND DIFFERENTIATE INTO A VARIETY OF MEMORY AND EFFECTOR CELL TYPES. CD8(+) T CELLS CAN PERSIST FOR YEARS AND KILL TUMOUR CELLS AND VIRALLY INFECTED CELLS. THE FUNCTIONAL AND PHENOTYPIC CHANGES THAT OCCUR DURING CD8(+) T CELL DIFFERENTIATION ARE WELL CHARACTERIZED, BUT THE EPIGENETIC STATES THAT UNDERLIE THESE CHANGES ARE INCOMPLETELY UNDERSTOOD. HERE, WE REVIEW THE EPIGENETIC PROCESSES THAT DIRECT CD8(+) T CELL DIFFERENTIATION AND FUNCTION. WE FOCUS ON EPIGENETIC MODIFICATION OF DNA AND ASSOCIATED HISTONES AT GENES AND THEIR REGULATORY ELEMENTS. WE ALSO DESCRIBE STRUCTURAL CHANGES IN CHROMATIN ORGANIZATION THAT AFFECT GENE EXPRESSION. FINALLY, WE EXAMINE THE TRANSLATIONAL POTENTIAL OF EPIGENETIC INTERVENTIONS TO IMPROVE CD8(+) T CELL FUNCTION IN INDIVIDUALS WITH CHRONIC INFECTIONS AND CANCER. 2018