1 604 171 BEYOND BROODING ON ONCOMETABOLIC HAVOC IN IDH-MUTANT GLIOMAS AND AML: CURRENT AND FUTURE THERAPEUTIC STRATEGIES. ISOCITRATE DEHYDROGENASES 1 AND 2 (IDH1,2), THE KEY KREBS CYCLE ENZYMES THAT GENERATE NADPH REDUCING EQUIVALENTS, UNDERGO HETEROZYGOUS MUTATIONS IN >70% OF LOW- TO MID-GRADE GLIOMAS AND ~20% OF ACUTE MYELOID LEUKEMIAS (AMLS) AND GAIN AN UNUSUAL NEW ACTIVITY OF REDUCING THE ALPHA-KETOGLUTARATE (ALPHA-KG) TO D-2 HYDROXYGLUTARATE (D-2HG) IN A NADPH-CONSUMING REACTION. THE ONCOMETABOLITE D-2HG, WHICH ACCUMULATES >35 MM, IS WIDELY ACCEPTED TO DRIVE A PROGRESSIVE ONCOGENESIS BESIDES EXACERBATING THE ALREADY INCREASED OXIDATIVE STRESS IN THESE CANCERS. MORE IMPORTANTLY, D-2HG COMPETES WITH ALPHA-KG AND INHIBITS A LARGE NUMBER OF ALPHA-KG-DEPENDENT DIOXYGENASES SUCH AS TET (TEN-ELEVEN TRANSLOCATION), JMJC DOMAIN-CONTAINING KDMS (HISTONE LYSINE DEMETHYLASES), AND THE ALKBH DNA REPAIR PROTEINS THAT ULTIMATELY LEAD TO HYPERMETHYLATION OF THE CPG ISLANDS IN THE GENOME. THE RESULTING CPG ISLAND METHYLATOR PHENOTYPE (CIMP) ACCOUNTS FOR MAJOR GENE EXPRESSION CHANGES INCLUDING THE SILENCING OF THE MGMT (O(6)-METHYLGUANINE DNA METHYLTRANSFERASE) REPAIR PROTEIN IN GLIOMAS. GLIOMA PATIENTS WITH IDH1 MUTATIONS ALSO SHOW BETTER THERAPEUTIC RESPONSES AND LONGER SURVIVAL, THE REASONS FOR WHICH ARE YET UNCLEAR. THERE HAS BEEN A GREAT SURGE IN DRUG DISCOVERY FOR CURTAILING THE MUTANT IDH ACTIVITIES, AND ARRESTING TUMOR PROLIFERATION; HOWEVER, GIVEN THE UNIQUE AND CHRONIC METABOLIC EFFECTS OF D-2HG, THE PROMISE OF THESE COMPOUNDS FOR GLIOMA TREATMENT IS UNCERTAIN. THIS COMPREHENSIVE REVIEW DISCUSSES THE BIOLOGY, CURRENT DRUG DESIGN AND OPPORTUNITIES FOR IMPROVED THERAPIES THROUGH EXPLOITABLE SYNTHETIC LETHALITY PATHWAYS, AND AN INTRIGUING ONCOMETABOLITE-INSPIRED STRATEGY FOR PRIMARY GLIOBLASTOMA. 2018 2 4261 38 MGMT-METHYLATION IN NON-NEOPLASTIC DISEASES OF THE CENTRAL NERVOUS SYSTEM. QUANTIFYING O(6)-METHYLGUANINE-DNA METHYLTRANSFERASE (MGMT) PROMOTER METHYLATION PLAYS AN ESSENTIAL ROLE IN ASSESSING THE POTENTIAL EFFICACY OF ALKYLATING AGENTS IN THE CHEMOTHERAPY OF MALIGNANT GLIOMAS. MGMT PROMOTER METHYLATION IS CONSIDERED TO BE A CHARACTERISTIC OF SUBGROUPS OF CERTAIN MALIGNANCIES BUT HAS ALSO BEEN DESCRIBED IN VARIOUS PERIPHERAL INFLAMMATORY DISEASES. HOWEVER, MGMT PROMOTER METHYLATION LEVELS HAVE NOT YET BEEN INVESTIGATED IN NON-NEOPLASTIC BRAIN DISEASES. THIS STUDY DEMONSTRATES FOR THE FIRST TIME THAT ONE CAN INDEED DETECT SLIGHTLY ENHANCED MGMT PROMOTER METHYLATION IN INDIVIDUAL CASES OF INFLAMMATORY DEMYELINATING CNS DISEASES SUCH AS MULTIPLE SCLEROSIS AND PROGRESSIVE MULTIFOCAL LEUCENCEPHALOPATHY (PML), AS WELL AS IN OTHER DEMYELINATING DISEASES SUCH AS CENTRAL PONTINE AND EXPTRAPONTINE MYELINOLYSIS, AND DISEASES WITH MYELIN DAMAGE SUCH AS WALLERIAN DEGENERATION. IN THIS CONTEXT, WE IDENTIFIED A REDUCTION IN THE EXPRESSION OF THE DEMETHYLASE TET1 AS A POSSIBLE CAUSE FOR THE ENHANCED MGMT PROMOTER METHYLATION. HENCE, WE SHOW FOR THE FIRST TIME THAT MGMT HYPERMETHYLATION OCCURS IN CHRONIC DISEASES THAT ARE NOT STRICTLY ASSOCIATED TO DISTINCT PATHOGENS, ONCOGENIC VIRUSES OR NEOPLASMS BUT THAT LEAD TO DAMAGE OF THE MYELIN SHEATH IN VARIOUS WAYS. WHILE THIS GIVES NEW INSIGHTS INTO EPIGENETIC AND PATHOPHYSIOLOGICAL PROCESSES INVOLVED IN DE- AND REMYELINATION, WHICH MIGHT OFFER NEW THERAPEUTIC OPPORTUNITIES FOR DEMYELINATING DISEASES IN THE FUTURE, IT ALSO REDUCES THE SPECIFICITY OF MGMT HYPERMETHYLATION AS A TUMOR BIOMARKER. 2021 3 1260 29 CURRENT VIEWS ON THE INTERPLAY BETWEEN TYROSINE KINASES AND PHOSPHATASES IN CHRONIC MYELOID LEUKEMIA. CHRONIC MYELOID LEUKEMIA (CML) IS A MYELOPROLIFERATIVE DISORDER CHARACTERIZED BY BCR-ABL1 ONCOGENE EXPRESSION. THIS DYSREGULATED PROTEIN-TYROSINE KINASE (PTK) IS KNOWN AS THE PRINCIPAL DRIVER OF THE DISEASE AND IS TARGETED BY TYROSINE KINASE INHIBITORS (TKIS). EXTENSIVE DOCUMENTATION HAS ELUCIDATED HOW THE TRANSFORMATION OF MALIGNANT CELLS IS CHARACTERIZED BY MULTIPLE GENETIC/EPIGENETIC CHANGES LEADING TO THE LOSS OF TUMOR-SUPPRESSOR GENES FUNCTION OR PROTO-ONCOGENES EXPRESSION. THE IMPAIRMENT OF ADEQUATE LEVELS OF SUBSTRATES PHOSPHORYLATION, THUS AFFECTING THE BALANCE PTKS AND PROTEIN PHOSPHATASES (PPS), REPRESENTS A WELL-ESTABLISHED CELLULAR MECHANISM TO ESCAPE FROM SELF-LIMITING SIGNALS. IN THIS REVIEW, WE FOCUS OUR ATTENTION ON THE CHARACTERIZATION OF AND INTERACTIONS BETWEEN PTKS AND PPS, EMPHASIZING THEIR BIOLOGICAL ROLES IN DISEASE EXPANSION, THE REGULATION OF LSCS AND TKI RESISTANCE. WE DECIDED TO SEPARATE THOSE PPS THAT HAVE BEEN VALIDATED IN PRIMARY CELL MODELS OR LEUKEMIA MOUSE MODELS FROM THOSE WHOSE STUDIES HAVE BEEN PERFORMED ONLY IN CELL LINES (AND, THUS, REQUIRE VALIDATION), AS THERE MAY BE DIFFERENCES IN THE MANNER THAT THE ASSOCIATED PATHWAYS ARE MODIFIED UNDER THESE TWO CONDITIONS. THIS REVIEW SUMMARIZES THE ROLES OF DIVERSE PPS, WITH HOPE THAT BETTER KNOWLEDGE OF THE INTERPLAY AMONG PHOSPHATASES AND KINASES WILL EVENTUALLY RESULT IN A BETTER UNDERSTANDING OF THIS DISEASE AND CONTRIBUTE TO ITS ERADICATION. 2021 4 1902 31 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 5 3195 30 HDAC INHIBITORS AUGMENTED CELL MIGRATION AND METASTASIS THROUGH INDUCTION OF PKCS LEADING TO IDENTIFICATION OF LOW TOXICITY MODALITIES FOR COMBINATION CANCER THERAPY. PURPOSE: HISTONE DEACETYLASE INHIBITORS (HDACI) ARE ACTIVELY EXPLORED AS NEW-GENERATION EPIGENETIC DRUGS BUT HAVE LOW EFFICACY IN CANCER MONOTHERAPY. TO REVEAL NEW MECHANISM FOR COMBINATION THERAPY, WE SHOW THAT HDACI INDUCE CELL DEATH BUT SIMULTANEOUSLY ACTIVATE TUMOR-PROGRESSIVE GENES TO RUIN THERAPEUTIC EFFICACY. COMBINED TREATMENTS TO TARGET TUMORIGENESIS AND HDACI-ACTIVATED METASTASIS WITH LOW TOXIC MODALITIES COULD DEVELOP NEW STRATEGIES FOR LONG-TERM CANCER THERAPY. EXPERIMENTAL DESIGN: BECAUSE METASTASIS IS THE MAJOR CAUSE OF CANCER MORTALITY, WE MEASURED CELL MIGRATION ACTIVITY AND PROFILED METASTASIS-RELATED GENE EXPRESSIONS IN HDACI-TREATED CANCER CELLS. WE DEVELOPED LOW TOXIC COMBINATION MODALITIES TARGETING TUMORIGENESIS AND HDACI-ACTIVATED METASTASIS FOR PRECLINICAL THERAPIES IN MICE. RESULTS: WE SHOWED THAT CELL MIGRATION ACTIVITY WAS DRAMATICALLY AND DOSE DEPENDENTLY ENHANCED BY VARIOUS CLASSES OF HDACI TREATMENTS IN 13 OF 30 EXAMINED HUMAN BREAST, GASTRIC, LIVER, AND LUNG CANCER CELL LINES. TUMOR METASTASIS WAS ALSO ENHANCED IN HDACI-TREATED MICE. HDACI TREATMENTS ACTIVATED MULTIPLE PKCS AND DOWNSTREAM SUBSTRATES ALONG WITH UPREGULATED PROAPOPTOTIC P21. FOR TARGETING TUMORIGENESIS AND METASTASIS WITH IMMEDIATE CLINICAL IMPACT, WE SHOWED THAT NEW MODALITIES OF HDACI COMBINED DRUGS WITH PKC INHIBITORY AGENT, CURCUMIN OR TAMOXIFEN, NOT ONLY SUPPRESSED HDACI-ACTIVATED TUMOR PROGRESSIVE PROTEINS AND CELL MIGRATION IN VITRO BUT ALSO INHIBITED TUMOR GROWTH AND METASTASIS IN VIVO. CONCLUSION: TREATMENTS OF DIFFERENT STRUCTURAL CLASSES OF HDACI SIMULTANEOUSLY INDUCED CELL DEATH AND PROMOTED CELL MIGRATION AND METASTASIS IN MULTIPLE CANCER CELL TYPES. SUPPRESSION OF HDACI-INDUCED PKCS LEADS TO DEVELOPMENT OF LOW TOXIC AND LONG-TERM THERAPEUTIC STRATEGIES TO POTENTIALLY TREAT CANCER AS A CHRONIC DISEASE. 2012 6 5688 36 SILENCING EFFECTS OF MUTANT RAS SIGNALLING ON TRANSCRIPTOMES. MUTATED GENES OF THE RAS FAMILY ENCODING SMALL GTP-BINDING PROTEINS DRIVE NUMEROUS CANCERS, INCLUDING PANCREATIC, COLON AND LUNG TUMORS. BESIDES THE NUMEROUS EFFECTS OF MUTANT RAS GENE EXPRESSION ON ABERRANT PROLIFERATION, TRANSFORMED PHENOTYPES, METABOLISM, AND THERAPY RESISTANCE, THE MOST STRIKING CONSEQUENCES OF CHRONIC RAS ACTIVATION ARE CHANGES OF THE GENETIC PROGRAM. BY PERFORMING SYSTEMATIC GENE EXPRESSION STUDIES IN CELLULAR MODELS THAT ALLOW COMPARISONS OF PRE-NEOPLASTIC WITH RAS-TRANSFORMED CELLS, WE AND OTHERS HAVE ESTIMATED THAT 7 PERCENT OR MORE OF ALL TRANSCRIPTS ARE ALTERED IN CONJUNCTION WITH THE EXPRESSION OF THE ONCOGENE. IN THIS CONTEXT, THE NUMBER OF UP-REGULATED TRANSCRIPTS APPROXIMATES THAT OF DOWN-REGULATED TRANSCRIPTS. WHILE UP-REGULATED TRANSCRIPTION FACTORS SUCH AS MYC, FOSL1, AND HMGA2 HAVE BEEN IDENTIFIED AND CHARACTERIZED AS RAS-RESPONSIVE DRIVERS OF THE ALTERED TRANSCRIPTOME, THE SUPPRESSED FACTORS HAVE BEEN LESS WELL STUDIED AS POTENTIAL REGULATORS OF THE GENETIC PROGRAM AND TRANSFORMED PHENOTYPE IN THE BREADTH OF THEIR OCCURRENCE. WE THEREFORE HAVE COLLECTED INFORMATION ON DOWNREGULATED RAS-RESPONSIVE FACTORS AND DISCUSS THEIR POTENTIAL ROLE AS TUMOR SUPPRESSORS THAT ARE LIKELY TO ANTAGONIZE ACTIVE CANCER DRIVERS. TO BETTER UNDERSTAND THE ACTIVE MECHANISMS THAT ENTAIL ANTI-RAS FUNCTION AND THOSE THAT LEAD TO LOSS OF TUMOR SUPPRESSOR ACTIVITY, WE FOCUS ON THE TUMOR SUPPRESSOR HREV107 (ALIAS PLAAT3 [PHOSPHOLIPASE A AND ACYLTRANSFERASE 3], PLA2G16 [PHOSPHOLIPASE A2, GROUP XVI] AND HRASLS3 [HRAS-LIKE SUPPRESSOR 3]). INACTIVATING HREV107 MUTATIONS IN TUMORS ARE EXTREMELY RARE, HENCE EPIGENETIC CAUSES MODULATED BY THE RAS PATHWAY ARE LIKELY TO LEAD TO DOWN-REGULATION AND LOSS OF FUNCTION. 2023 7 4837 29 ONCOGENIC GENE EXPRESSION AND EPIGENETIC REMODELING OF CIS-REGULATORY ELEMENTS IN ASXL1-MUTANT CHRONIC MYELOMONOCYTIC LEUKEMIA. MYELOID NEOPLASMS ARE CLONAL HEMATOPOIETIC STEM CELL DISORDERS DRIVEN BY THE SEQUENTIAL ACQUISITION OF RECURRENT GENETIC LESIONS. TRUNCATING MUTATIONS IN THE CHROMATIN REMODELER ASXL1 (ASXL1(MT)) ARE ASSOCIATED WITH A HIGH-RISK DISEASE PHENOTYPE WITH INCREASED PROLIFERATION, EPIGENETIC THERAPEUTIC RESISTANCE, AND POOR SURVIVAL OUTCOMES. WE PERFORMED A MULTI-OMICS INTERROGATION TO DEFINE GENE EXPRESSION AND CHROMATIN REMODELING ASSOCIATED WITH ASXL1(MT) IN CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML). ASXL1(MT) ARE ASSOCIATED WITH A LOSS OF REPRESSIVE HISTONE METHYLATION AND INCREASE IN PERMISSIVE HISTONE METHYLATION AND ACETYLATION IN PROMOTER REGIONS. ASXL1(MT) ARE FURTHER ASSOCIATED WITH DE NOVO ACCESSIBILITY OF DISTAL ENHANCERS BINDING ETS TRANSCRIPTION FACTORS, TARGETING IMPORTANT LEUKEMOGENIC DRIVER GENES. CHROMATIN REMODELING OF PROMOTERS AND ENHANCERS IS STRONGLY ASSOCIATED WITH GENE EXPRESSION AND HETEROGENOUS AMONG OVEREXPRESSED GENES. THESE RESULTS PROVIDE A COMPREHENSIVE MAP OF THE TRANSCRIPTOME AND CHROMATIN LANDSCAPE OF ASXL1(MT) CMML, FORMING AN IMPORTANT FRAMEWORK FOR THE DEVELOPMENT OF NOVEL THERAPEUTIC STRATEGIES TARGETING ONCOGENIC CIS INTERACTIONS. 2022 8 5825 32 STRESS MODULATES AHI1-DEPENDENT NUCLEAR LOCALIZATION OF TEN-ELEVEN TRANSLOCATION PROTEIN 2. MAJOR DEPRESSION DISORDER IS ONE OF THE MOST COMMON PSYCHIATRIC DISEASES. RECENT EVIDENCE SUPPORTS THAT ENVIRONMENTAL STRESS AFFECTS GENE EXPRESSION AND PROMOTES THE PATHOLOGICAL PROCESS OF DEPRESSION THROUGH EPIGENETIC MECHANISMS. THREE TEN-ELEVEN TRANSLOCATION (TET) ENZYMES ARE EPIGENETIC REGULATORS OF GENE EXPRESSION THAT PROMOTE 5-HYDROXYMETHYLCYTOSINE (5HMC) MODIFICATION OF GENES. HERE, WE SHOW THAT THE LOSS OF TET2 CAN INDUCE DEPRESSION-LIKE PHENOTYPES IN MICE. PARADOXICALLY, USING THE PARADIGMS OF CHRONIC STRESS, SUCH AS CHRONIC MILD STRESS AND CHRONIC SOCIAL DEFEAT STRESS, WE FOUND THAT DEPRESSIVE BEHAVIORS WERE ASSOCIATED WITH INCREASED TET2 EXPRESSION BUT DECREASED GLOBAL 5HMC LEVEL IN HIPPOCAMPUS. WE EXAMINED THE GENOME-WIDE 5HMC PROFILE IN THE HIPPOCAMPUS OF TET2 KNOCKOUT MICE AND IDENTIFIED 651 DYNAMICALLY HYDROXYMETHYLATED REGIONS, SOME OF WHICH OVERLAPPED WITH KNOWN DEPRESSION-ASSOCIATED LOCI. WE FURTHER SHOWED THAT CHRONIC STRESS COULD INDUCE THE ABNORMAL NUCLEAR TRANSLOCATION OF TET2 PROTEIN FROM CYTOSOL. THROUGH TET2 IMMUNOPRECIPITATION AND MASS SPECTRUM ANALYSES, WE IDENTIFIED A CELLULAR TRAFFICKING PROTEIN, ABELSON HELPER INTEGRATION SITE-1 (AHI1), WHICH COULD INTERACT WITH TET2 PROTEIN. AHI1 KNOCKOUT OR KNOCKDOWN CAUSED THE ACCUMULATION OF TET2 IN CYTOSOL. THE REDUCTION OF AHI1 PROTEIN UNDER CHRONIC STRESS EXPLAINED THE ABNORMAL AHI1-DEPENDENT NUCLEAR TRANSLOCATION OF TET2. THESE FINDINGS TOGETHER PROVIDE THE EVIDENCE FOR A CRITICAL ROLE OF MODULATING TET2 NUCLEAR TRANSLOCATION IN REGULATING STRESS RESPONSE. 2021 9 2025 29 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 10 19 32 5-AZACYTYDINE AND RESVERATROL REVERSE SENESCENCE AND AGEING OF ADIPOSE STEM CELLS VIA MODULATION OF MITOCHONDRIAL DYNAMICS AND AUTOPHAGY. OBESITY AND ENDOCRINE DISORDERS HAVE BECOME PREVALENT ISSUES IN THE FIELD OF BOTH HUMAN AND VETERINARY MEDICINE. EQUINE METABOLIC SYNDROME IS A COMPLEX DISORDER INVOLVING ALTERNATION IN METABOLISM AND CHRONIC SYSTEMIC INFLAMMATION. IT HAS BEEN SHOWN THAT UNFAVOURABLE MICROENVIRONMENT OF INFLAMED ADIPOSE TISSUE NEGATIVELY AFFECTS ADIPOSE STEM CELL POPULATION (ASC) RESIDING WITHIN, MARKEDLY LIMITING THEIR THERAPEUTIC POTENTIAL. ASCS(EMS) ARE CHARACTERIZED BY INCREASED SENESCENCE APOPTOSIS, EXCESSIVE ACCUMULATION OF REACTIVE OXYGEN SPECIES (ROS), MITOCHONDRIA DETERIORATION AND "AUTOPHAGIC FLUX." THE AIM OF THE PRESENT STUDY WAS TO EVALUATE WHETHER TREATMENT OF ASCS(EMS) WITH A COMBINATION OF 5-AZACYTYDINE (AZA) AND RESVERATROL (RES) WOULD REVERSE AGED PHENOTYPE OF THESE CELLS. FOR THIS REASON, WE PERFORMED THE FOLLOWING ANALYZES: MOLECULAR BIOLOGY (RT-PCR), MICROSCOPIC (IMMUNOFLUORESCENCE, TEM) AND FLOW CYTOMETRY (JC-1, ROS, KI67). WE EVALUATED THE MITOCHONDRIAL STATUS, DYNAMICS AND CLEARANCE AS WELL AS AUTOPHAGIC PATHWAYS. FURTHERMORE, WE INVESTIGATED EPIGENETIC ALTERNATIONS IN TREATED CELLS BY MEASURING THE EXPRESSION OF TET GENES AND ANALYSIS OF DNA METHYLATION STATUS. WE HAVE DEMONSTRATED THAT AZA/RES TREATMENT OF ASCS(EMS) IS ABLE TO REJUVENATE THESE CELLS BY MODULATING MITOCHONDRIAL DYNAMICS, IN PARTICULAR BY PROMOTING MITOCHONDRIAL FUSION OVER FISSION. AFTER AZA/RES TREATMENT, ASCS(EMS) WERE CHARACTERIZED BY INCREASED PROLIFERATION RATE, DECREASED APOPTOSIS AND SENESCENCE AND LOWER ROS ACCUMULATION. OUR FINDINGS OFFER A NOVEL APPROACH AND POTENTIAL TARGETS FOR THE BENEFICIAL EFFECTS OF AZA/RES IN AMELIORATING STEM CELL DYSFUNCTIONS. 2019 11 5785 19 SPONTANEOUS NEOPLASTIC TRANSFORMATION OF WB-F344 RAT LIVER EPITHELIAL CELLS. SEVERAL STUDIES HAVE SHOWN THAT CULTURED RAT LIVER EPITHELIAL CELLS TRANSFORM SPONTANEOUSLY AFTER CHRONIC MAINTENANCE IN A CONFLUENT STATE IN VITRO. IN THE PRESENT STUDY, MULTIPLE INDEPENDENT LINEAGES OF LOW-PASSAGE WB-F344 RAT LIVER EPITHELIAL STEM-LIKE CELLS WERE INITIATED AND SUBJECTED IN PARALLEL TO SELECTION FOR SPONTANEOUS TRANSFORMATION TO DETERMINE WHETHER SPONTANEOUS ACQUISITION OF TUMORIGENICITY WAS THE RESULT OF EVENTS (GENETIC OR EPIGENETIC) THAT OCCURRED INDEPENDENTLY AND STOCHASTICALLY, OR REFLECTED THE EXPRESSION OF A PRE-EXISTING ALTERATION WITHIN THE PARENTAL WB-F344 CELL LINE. TEMPORAL ANALYSIS OF THE SPONTANEOUS ACQUISITION OF TUMORIGENICITY BY WB-F344 CELLS DEMONSTRATED LINEAGE-SPECIFIC DIFFERENCES IN THE TIME OF FIRST EXPRESSION OF THE TUMORIGENIC PHENOTYPE, FREQUENCIES AND LATENCIES OF TUMOR FORMATION, AND TUMOR DIFFERENTIATIONS. ALTHOUGH SPONTANEOUSLY TRANSFORMED WB-F344 CELLS PRODUCED DIVERSE TUMOR TYPES (INCLUDING HEPATOCELLULAR CARCINOMAS, CHOLANGIOCARCINOMAS, HEPATOBLASTOMAS, AND OSTEOGENIC SARCOMAS), INDIVIDUAL LINEAGES YIELDED TUMORS WITH CONSISTENT AND SPECIFIC PATTERNS OF DIFFERENTIATION. THESE RESULTS PROVIDE SUBSTANTIAL EVIDENCE THAT THE STOCHASTIC ACCUMULATION OF INDEPENDENT TRANSFORMING EVENTS DURING THE SELECTION REGIMEN IN VITRO WERE RESPONSIBLE FOR SPONTANEOUS NEOPLASTIC TRANSFORMATION OF WB-F344 CELLS. FURTHERMORE, CELL LINEAGE COMMITMENT TO A SPECIFIC DIFFERENTIATION PROGRAM WAS STABLE WITH TIME IN CULTURE AND WITH SITE OF TRANSPLANTATION. THIS IS THE FIRST REPORT OF A COHORT OF RELATED, BUT INDEPENDENT, RAT LIVER EPITHELIAL CELL LINES THAT COLLECTIVELY PRODUCE A SPECTRUM OF TUMOR TYPES BUT INDIVIDUALLY REPRODUCE A SPECIFIC TUMOR TYPE. THESE CELL LINES WILL PROVIDE VALUABLE REAGENTS FOR INVESTIGATION OF THE MOLECULAR MECHANISMS INVOLVED IN THE DIFFERENTIATION OF HEPATIC STEM-LIKE CELLS AND FOR EXAMINATION OF POTENTIAL CAUSAL RELATIONSHIPS IN SPONTANEOUSLY TRANSFORMED RAT LIVER EPITHELIAL CELL LINES BETWEEN MOLECULAR/CELLULAR ALTERATIONS AND THE ABILITY TO PRODUCE TUMORS IN SYNGENEIC ANIMALS. 1998 12 5982 33 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 13 3823 35 INVESTIGATING THE EFFECTS OF A SYNTHETIC CANNABINOID ON THE PATHOGENESIS OF LEUKEMIA AND LEUKEMIC STEM CELLS: A NEW THERAPEUTIC APPROACH. THE POPULARITY AND USAGE OF SYNTHETIC CANNABINOIDS (SCS) ARE INCREASING DUE TO THEIR EASY ACCESSIBILITY AND PSYCHOACTIVE EFFECTS WORLDWIDE. STUDIES ON CANNABINOIDS ON LEUKEMIC STEM CELLS (LSC) AND HEMATOPOIETIC STEM CELLS (HSCS), WHICH ARE THE PRECURSORS OF LEUKEMIA CELLS, GENERALLY DEPEND ON THE NATURAL CANNABINOID DELTA-9-THC. AS THERE IS ONLY A LIMITED NUMBER OF STUDIES FOCUSING ON THE RESULTS OF SC APPLICATIONS, THE REFLECTIONS UPON LSCS HAVE TO BE CLARIFIED. IN THIS STUDY, BIOLOGICAL RESPONSES AND ANTILEUKEMIC EFFECTS OF JWH-018-ONE OF THE FIRST PRODUCED AND WIDELY USED SCS-WERE EVALUATED UPON LEUKEMIA CELLS. WHETHER JWH-018 EXHIBITED A PREVENTIVE EFFECT ON BOTH LEUKEMIC AND HSCS WAS EVALUATED BY PRESENTING A THERAPEUTIC APPROACH FOR THE FIRST TIME IN THE LITERATURE. CELLS WERE ANALYZED IN CASE OF CELL PROLIFERATION, APOPTOSIS, AND TRANSCRIPTIONAL EXPRESSION PROFILING OF SOME SIGNIFICANT JAK/STAT AND AKT/MTOR PATHWAYS, APOPTOTIC, CELL CYCLE REGULATION, AND EPIGENETIC CHROMATIN REMODELING-RELATED GENES FOLLOWING JWH-018 TREATMENT. IN CONCLUSION, HOWEVER, FURTHER STUDIES ARE STILL NEEDED UPON BOTH HSCS AND LSCS TO ILLUMINATE THE EFFECTS OF SCS ON LEUKEMOGENESIS ON CHRONIC MYELOID LEUKEMIA (CML) MORE CLEARLY; WE CONSIDER THAT THE JWH-018 CAN PROVIDE A THERAPEUTIC EFFECT ON THE PATHOGENESIS OF LEUKEMIA AND PARTICULARLY UPON LSCS AND SCS MIGHT HAVE THERAPEUTIC POTENTIAL IN ADDITION TO CURRENT THERAPY. 2022 14 6584 32 TRIGGERING RECEPTORS EXPRESSED ON MYELOID CELLS 1 : OUR NEW PARTNER IN HUMAN ONCOLOGY? INFLAMMATION IS RECOGNIZED AS ONE OF THE HALLMARKS OF CANCER. INDEED, STRONG EVIDENCE INDICATES THAT CHRONIC INFLAMMATION PLAYS A MAJOR ROLE IN ONCOGENESIS, PROMOTING GENOME INSTABILITY, EPIGENETIC ALTERATIONS, PROLIFERATION AND DISSEMINATION OF CANCER CELLS. MONONUCLEAR PHAGOCYTES (MPS) HAVE BEEN IDENTIFIED AS KEY CONTRIBUTORS OF THE INFLAMMATORY INFILTRATE IN SEVERAL SOLID HUMAN NEOPLASIA, PROMOTING ANGIOGENESIS AND CANCER PROGRESSION. ONE OF THE MOST DESCRIBED AMPLIFIERS OF MPS PRO-INFLAMMATORY INNATE IMMUNE RESPONSE IS THE TRIGGERING RECEPTORS EXPRESSED ON MYELOID CELLS 1 (TREM-1). GROWING EVIDENCE SUGGESTS TREM-1 INVOLVEMENT IN ONCOGENESIS THROUGH CANCER RELATED INFLAMMATION AND THE SURROUNDING TUMOR MICROENVIRONMENT. IN HUMAN ONCOLOGY, HIGH LEVELS OF TREM-1 AND/OR ITS SOLUBLE FORM HAVE BEEN ASSOCIATED WITH POORER SURVIVAL DATA IN SEVERAL SOLID MALIGNANCIES, ESPECIALLY IN HEPATOCELLULAR CARCINOMA AND LUNG CANCER. TREM-1 SHOULD BE CONSIDERED AS A POTENTIAL BIOMARKER IN HUMAN ONCOLOGY AND COULD BE USED AS A NEW THERAPEUTIC TARGET OF INTEREST IN HUMAN ONCOLOGY (TREM-1 INHIBITORS, TREM-1 AGONISTS). MORE CLINICAL STUDIES ARE URGENTLY NEEDED TO CONFIRM TREM-1 (AND TREM FAMILY) ROLES IN THE PROGNOSIS AND THE TREATMENT OF HUMAN SOLID CANCERS. 2022 15 4558 30 MUTATIONS IN THE NF-KAPPAB SIGNALING PATHWAY: IMPLICATIONS FOR HUMAN DISEASE. THE NUCLEAR FACTOR-KAPPA B (NF-KAPPAB) SIGNALING PATHWAY IS A MULTI-COMPONENT PATHWAY THAT REGULATES THE EXPRESSION OF HUNDREDS OF GENES THAT ARE INVOLVED IN DIVERSE AND KEY CELLULAR AND ORGANISMAL PROCESSES, INCLUDING CELL PROLIFERATION, CELL SURVIVAL, THE CELLULAR STRESS RESPONSE, INNATE IMMUNITY AND INFLAMMATION. NOT SURPRISINGLY, MIS-REGULATION OF THE NF-KAPPAB PATHWAY, EITHER BY MUTATION OR EPIGENETIC MECHANISMS, IS INVOLVED IN MANY HUMAN AND ANIMAL DISEASES, ESPECIALLY ONES ASSOCIATED WITH CHRONIC INFLAMMATION, IMMUNODEFICIENCY OR CANCER. THIS REVIEW DESCRIBES HUMAN DISEASES IN WHICH MUTATIONS IN THE COMPONENTS OF THE CORE NF-KAPPAB SIGNALING PATHWAY HAVE BEEN IMPLICATED AND DISCUSSES THE MOLECULAR MECHANISMS BY WHICH THESE ALTERATIONS IN NF-KAPPAB SIGNALING ARE LIKELY TO CONTRIBUTE TO THE DISEASE PATHOLOGY. THESE MUTATIONS CAN BE GERMLINE OR SOMATIC AND INCLUDE GENE AMPLIFICATION (E.G., REL), POINT MUTATIONS AND DELETIONS (REL, NFKB2, IKBA, CYLD, NEMO) AND CHROMOSOMAL TRANSLOCATIONS (BCL-3). IN ADDITION, HUMAN GENETIC DISEASES ARE BRIEFLY DESCRIBED WHEREIN MUTATIONS AFFECT PROTEIN MODIFIERS OR TRANSDUCERS OF NF-KAPPAB SIGNALING OR DISRUPT NF-KAPPAB-BINDING SITES IN PROMOTERS/ENHANCERS. 2006 16 4545 33 MUTANT P53 GAIN OF FUNCTION AND CHEMORESISTANCE: THE ROLE OF MUTANT P53 IN RESPONSE TO CLINICAL CHEMOTHERAPY. PURPOSE: TO REVIEW MECHANISMS UNDERLYING MUTANT P53 (MUTP53) GAIN OF FUNCTION (GOF) AND MUTP53-INDUCED CHEMORESISTANCE, AND TO INVESTIGATE THE ROLE OF MUTP53 IN RESPONSE TO CLINICAL CHEMOTHERAPY. METHODS: WE SEARCHED THE PUBMED DATABASE FOR CLINICAL STUDIES FROM THE PAST DECADE, INCLUDING DATA EVALUATING THE IMPACT OF MUTP53 IN CLINICAL CHEMOTHERAPY RESPONSE. RESULTS: INTERACTIONS BETWEEN MUTP53 AND TRANSCRIPTIONAL FACTORS, PROTEINS OR DNA STRUCTURES, AS WELL AS EPIGENETIC REGULATION, CONTRIBUTE TO MUTP53 GOF. MAJOR MECHANISMS OF MUTP53-INDUCED CHEMORESISTANCE INCLUDE ENHANCED DRUG EFFLUX AND METABOLISM, PROMOTING SURVIVAL, INHIBITING APOPTOSIS, UPREGULATING DNA REPAIR, SUPPRESSING AUTOPHAGY, ELEVATING MICROENVIRONMENTAL RESISTANCE AND INDUCING A STEM-LIKE PHENOTYPE. CLINICALLY, MUTP53 PREDICTED RESISTANCE TO CHEMOTHERAPY IN DIFFUSE LARGE B-CELL LYMPHOMA, AND ESOPHAGEAL AND OROPHARYNGEAL CANCERS, BUT ITS IMPACT ON CHRONIC LYMPHOCYTIC LEUKEMIA WAS UNCLEAR. IN BLADDER CANCER, MUTP53 DID NOT PREDICT RESISTANCE, WHEREAS IN SOME BREAST AND OVARIAN CANCERS, IT WAS ASSOCIATED WITH SENSITIVITY TO CERTAIN CHEMOTHERAPEUTIC AGENTS. CONCLUSION: MUTP53 HAS AN INTRICATE ROLE IN THE RESPONSE TO CLINICAL CHEMOTHERAPY AND SHOULD NOT BE INTERPRETED IN ISOLATION. FURTHERMORE, WHEN PREDICTING TUMOR RESPONSE TO CHEMOTHERAPY BASED ON THE P53 STATUS, THE DRUGS USED SHOULD ALSO BE TAKEN INTO CONSIDERATION. THESE CONCEPTS REQUIRE FURTHER INVESTIGATION. 2017 17 3115 35 GEROMETABOLITES: THE PSEUDOHYPOXIC AGING SIDE OF CANCER ONCOMETABOLITES. ONCOMETABOLITES ARE DEFINED AS SMALL-MOLECULE COMPONENTS (OR ENANTIOMERS) OF NORMAL METABOLISM WHOSE ACCUMULATION CAUSES SIGNALING DYSREGULATION TO ESTABLISH A MILIEU THAT INITIATES CARCINOGENESIS. IN A SIMILAR MANNER, WE PROPOSE THE TERM "GEROMETABOLITES" TO REFER TO SMALL-MOLECULE COMPONENTS OF NORMAL METABOLISM WHOSE DEPLETION CAUSES SIGNALING DYSREGULATION TO ESTABLISH A MILIEU THAT DRIVES AGING. IN AN INVESTIGATION OF THE PATHOGENIC ACTIVITIES OF THE CURRENTLY RECOGNIZED ONCOMETABOLITES R(-)-2-HYDROXYGLUTARATE (2-HG), FUMARATE, AND SUCCINATE, WHICH ACCUMULATE DUE TO MUTATIONS IN ISOCITRATE DEHYDROGENASES (IDH), FUMARATE HYDRATASE (FH), AND SUCCINATE DEHYDROGENASE (SDH), RESPECTIVELY, WE ILLUSTRATE THE FACT THAT METABOLIC PSEUDOHYPOXIA, THE ACCUMULATION OF HYPOXIA-INDUCIBLE FACTOR (HIFALPHA) UNDER NORMOXIC CONDITIONS, AND THE SUBSEQUENT WARBURG-LIKE REPROGRAMMING THAT SHIFTS GLUCOSE METABOLISM FROM THE OXIDATIVE PATHWAY TO AEROBIC GLYCOLYSIS ARE THE SAME MECHANISMS THROUGH WHICH THE DECLINE OF THE "GEROMETABOLITE" NICOTINAMIDE ADENINE DINUCLEOTIDE (NAD)(+) REVERSIBLY DISRUPTS NUCLEAR-MITOCHONDRIAL COMMUNICATION AND CONTRIBUTES TO THE DECLINE IN MITOCHONDRIAL FUNCTION WITH AGE. FROM AN EVOLUTIONARY PERSPECTIVE, IT IS REASONABLE TO VIEW NAD(+)-DRIVEN MITOCHONDRIAL HOMEOSTASIS AS A CONSERVED RESPONSE TO CHANGES IN ENERGY SUPPLIES AND OXYGEN LEVELS. SIMILARLY, THE NATURAL ABILITY OF 2-HG TO SIGNIFICANTLY ALTER EPIGENETICS MIGHT REFLECT AN EVOLUTIONARILY ANCIENT ROLE OF CERTAIN METABOLITES TO SIGNAL FOR ELEVATED GLUTAMINE/GLUTAMATE METABOLISM AND/OR OXYGEN DEFICIENCY. HOWEVER, WHEN CHRONICALLY ALTERED, THESE RESPONSES BECOME CONSERVED CAUSES OF AGING AND CANCER. BECAUSE HIFALPHA-DRIVEN PSEUDOHYPOXIA MIGHT DRIVE THE OVERPRODUCTION OF 2-HG, THE INTRIGUING POSSIBILITY EXISTS THAT THE DECLINE OF GEROMETABOLITES SUCH AS NAD(+) COULD PROMOTE THE CHRONIC ACCUMULATION OF ONCOMETABOLITES IN NORMAL CELLS DURING AGING. IF THE SOLE ACTIVATION OF A WARBURG-LIKE METABOLIC REPROGRAMMING IN NORMAL TISSUES MIGHT BE ABLE TO SIGNIFICANTLY INCREASE THE ENDOGENOUS PRODUCTION OF BONA FIDE ETIOLOGICAL DETERMINANTS IN CANCER, SUCH AS ONCOMETABOLITES, THIS UNDESIRABLE TRADE-OFF BETWEEN MITOCHONDRIAL DYSFUNCTION AND ACTIVATION OF ONCOMETABOLITES PRODUCTION MIGHT THEN PAVE THE WAY FOR THE EPIGENETIC INITIATION OF CARCINOGENESIS IN A STRICTLY METABOLIC-DEPENDENT MANNER. PERHAPS IT IS TIME TO DEFINITELY ADOPT THE VIEW THAT AGING AND AGING DISEASES INCLUDING CANCER ARE GOVERNED BY A PIVOTAL REGULATORY ROLE OF METABOLIC REPROGRAMMING IN CELL FATE DECISIONS. 2014 18 402 26 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 19 1621 43 DNA METHYLTRANSFERASES AS TARGETS FOR CANCER THERAPY. METHYLATION OF DNA AT 5-POSITION OF CYTOSINE, CATALYZED BY DNA METHYLTRANSFERASES, IS THE PREDOMINANT EPIGENETIC MODIFICATION IN MAMMALS. ABERRATIONS IN METHYLATION PLAY A CAUSAL ROLE IN A VARIETY OF DISEASES, INCLUDING CANCER. RECENT STUDIES HAVE ESTABLISHED THAT LIKE MUTATION, METHYLATION-MEDIATED GENE SILENCING OFTEN LEADS TO TUMORIGENESIS. PARADOXICALLY, GENOME-WIDE DNA HYPOMETHYLATION MAY ALSO PLAY A CAUSAL ROLE IN CARCINOGENESIS BY INDUCING CHROMOSOMAL INSTABILITY AND SPURIOUS GENE EXPRESSION. SINCE METHYLATION DOES NOT ALTER DNA BASE SEQUENCE, MUCH ATTENTION HAS BEEN FOCUSED RECENTLY ON DEVELOPING SMALL MOLECULE INHIBITORS OF DNA METHYLTRANSFERASES THAT CAN POTENTIALLY BE USED AS ANTICANCER AGENTS. VIDAZA (5-AZACYTIDINE), MARKETED BY PHARMION (BOULDER, CO, USA), WAS THE FIRST DNA METHYLTRANSFERASE INHIBITOR APPROVED BY THE U.S. FOOD AND DRUG ADMINISTRATION (FDA) FOR CHEMOTHERAPY AGAINST MYELODYSPLASTIC SYNDROME (MDS), A HETEROGENEOUS BONE MARROW DISORDER. RECENTLY MGI PHARMA INC. (BLOOMINGTON, MN, USA) GOT FDA APPROVAL TO MARKET DACOGEN (5-AZA-2'-DEOXYCYTIDINE, OR DECITABINE) FOR TREATING MDS PATIENTS. THESE DRUGS WERE USED EARLIER AGAINST CERTAIN ANEMIAS TO INDUCE EXPRESSION OF FETAL GLOBIN GENES. INTEREST IN CLINICAL TRIALS OF THESE DRUGS AS ANTICANCER AGENTS HAS BEEN RENEWED ONLY RECENTLY BECAUSE OF REVERSAL OF METHYLATION-MEDIATED SILENCING OF CRITICAL GENES IN CANCER. CLINICAL TRIALS HAVE SHOWN THAT BOTH DRUGS HAVE THERAPEUTIC POTENTIAL AGAINST LEUKEMIA SUCH AS MDS, ACUTE MYELOID LEUKEMIA, CHRONIC MYELOGENOUS LEUKEMIA AND CHRONIC MYELOMONOCYTIC LEUKEMIA. IN CONTRAST, THEIR EFFECTIVENESS WITH SOLID TUMORS APPEARS TO BE LESS PROMISING, WHICH CHALLENGES RESEARCHERS TO DEVELOP INHIBITORS WITH MORE EFFICACY AND LESS TOXICITY. THE MAJOR HINDRANCE OF THEIR USAGE AS ANTICANCER AGENTS IS THEIR INSTABILITY IN VIVO AS WELL AS THE TOXICITY SECONDARY TO THEIR EXCESSIVE INCORPORATION INTO DNA, WHICH CAUSES CELL CYCLE ARREST. GENE EXPRESSION PROFILING IN CANCER CELLS REVEALED THAT ANTINEOPLASTIC PROPERTY OF THESE DRUGS IS MEDIATED THROUGH BOTH METHYLATION-DEPENDENT AND -INDEPENDENT PATHWAYS. RECENTLY, WE HAVE SHOWN THAT TREATMENT OF CANCER CELLS WITH THESE CYTIDINE ANALOGUES ALSO INDUCES PROTEASOMAL DEGRADATION OF DNA METHYLTRANSFERASE 1, THE UBIQUITOUSLY EXPRESSED ENZYME UPREGULATED IN ALMOST ALL CANCER CELLS. DEVELOPMENT OF RELATED STABLE DRUGS THAT CAN FACILITATE GENE ACTIVATION IN CANCER CELLS BY ENHANCING DEGRADATION OF DNA METHYLTRANSFERASES WITHOUT BEING INCORPORATED INTO DNA WOULD BE IDEAL FOR CHEMOTHERAPY. IN THIS MONOGRAPH WE REVIEW HISTORICAL PERSPECTIVE AND RECENT ADVANCES ON THE MOLECULAR MECHANISMS OF ACTION AND CLINICAL APPLICATIONS OF THESE DNA HYPOMETHYLATING AGENTS. 2007 20 5972 25 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