1 2665 143 ESTABLISHMENT OF A NOVEL MYELODYSPLASTIC SYNDROME (MDS) XENOTRANSPLANTATION MODEL. BACKGROUND: MYELODYSPLASTIC SYNDROME (MDS) IS A CLONAL DISEASE OF THE ELDERLY CHARACTERIZED BY CHRONIC CYTOPENIA, DYSPLASIA, AND A HIGH RISK OF PROGRESSION TO ACUTE MYELOID LEUKEMIA (AML). UP UNTIL NOW, FEW ANIMAL MODELS THAT FULLY RECAPITULATE CLINICAL FEATURES OF THIS DISEASE HAVE BEEN AVAILABLE. METHODS: THIS STUDY AIMED TO ESTABLISH A NEW MDS XENOGRAFT MODEL UTILIZING A HUMAN MDS-DERIVED CELL LINE WITH HETEROZYGOUS Y641C MUTATION OF EZH2 (SKM-1). 1 X 107 SKM-1 CELLS WERE INOCULATED INTO ANTI-MOUSE CD122 MONOANTIBODY CONDITIONED NONOBESE DIABETIC SEVERE COMBINED IMMUNODEFICIENCY (NOD/SCID) MICE BY INTRAVENOUS INJECTION. DECITABINE WAS INJECTED INTRAPERITONEALLY FOR EVALUATION OF EPIGENETIC DRUGS IN VIVO. RESULTS: IT IS SHOWN THAT THE HETEROZYGOUS Y641C MUTATION IN THE EZH2 GENE MUTATION, WHICH MAY DESTABILIZE THE PROTEIN (??G = 1.46 KCAL/MOL), CAN BE FOUND IN SKM-1 CELLS. MOST MICE PRESENTED ANEMIA AND LEUKOPENIA AT THREE TO FOUR WEEKS AFTER INOCULATION. THE PERIPHERAL BLOOD AND BONE MARROW SMEAR SHOWED PROMINENT DYSPLASIA ON ERYTHROCYTES AND GRANULOCYTES AS WELL AS MONOCYTES. CONCLUSIONS: THESE FINDINGS SUGGEST THAT INTRAVENOUS INOCULATION OF CELLS FROM THE HUMAN MDS-DERIVED CELL LINE PRIOR TO TARGETED DEPLETION OF CD122+ CELLS COULD PROVIDE A NOVEL MDS-LIKE XENOTRANSPLANT MOUSE MODEL. IT IS A USEFUL TOOL FOR EVALUATING POTENTIAL EXISTING AND NOVEL THERAPEUTICS FOR MDS. 2016 2 1901 37 ENGRAFTMENT OF CHRONIC MYELOMONOCYTIC LEUKEMIA CELLS IN IMMUNOCOMPROMISED MICE SUPPORTS DISEASE DEPENDENCY ON CYTOKINES. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL HEMATOPOIETIC STEM CELL DISORDER THAT TYPICALLY ASSOCIATES WITH MUTATIONS IN EPIGENETIC, SPLICING, AND SIGNALING GENES. GENETICALLY MODIFIED MOUSE MODELS ONLY PARTIALLY RECAPITULATE THE DISEASE PHENOTYPE, WHEREAS XENOTRANSPLANTATION OF CMML CELLS IN IMMUNOCOMPROMISED MICE HAS BEEN RARELY SUCCESSFUL SO FAR. HERE, CMML CD34(+) CELLS SORTED FROM PATIENT BONE MARROW (BM) OR PERIPHERAL BLOOD (PB) WERE INJECTED INTRAVENOUSLY INTO NSG (NOD/LTSZ-SCID IL2RGAMMANULL) MICE AND NSG MICE ENGINEERED TO EXPRESS HUMAN GRANULO-MONOCYTE COLONY-STIMULATING FACTOR, STEM CELL FACTOR, AND INTERLEUKIN-3 (NSGS MICE). FIFTEEN OUT OF 16 PATIENT SAMPLES (94%) SUCCESSFULLY ENGRAFTED INTO NSG OR NSGS OR BOTH MOUSE STRAINS. THE EXPANSION OF HUMAN CELLS, PREDOMINANT IN THE BM, WAS ALSO OBSERVED IN THE SPLEEN AND THE PB AND WAS GREATLY ENHANCED IN MICE PRODUCING THE 3 HUMAN CYTOKINES. GENE MUTATIONS IDENTIFIED IN ENGRAFTED CELLS WERE MOSTLY SIMILAR TO THOSE IDENTIFIED IN PATIENT CELLS BEFORE INJECTION. SUCCESSFUL SECONDARY ENGRAFTMENT WAS OBTAINED IN NSGS MICE IN 3 OUT OF 10 ATTEMPTS. THUS, PRIMARY CMML LEUKEMIC CELLS EXPAND MUCH BETTER IN NSGS COMPARED WITH NSG MICE WITH LIMITED EFFICACY OF SECONDARY TRANSPLANT. 2017 3 5924 27 TARGETING DNMT1 BY DEMETHYLATING AGENT OR-2100 INCREASES TYROSINE KINASE INHIBITORS-SENSITIVITY AND DEPLETES LEUKEMIC STEM CELLS IN CHRONIC MYELOID LEUKEMIA. ABL1 TYROSINE KINASE INHIBITORS (TKIS) DRAMATICALLY IMPROVE THE PROGNOSIS OF CHRONIC MYELOID LEUKEMIA (CML), BUT 10-20% OF PATIENTS ACHIEVE SUBOPTIMAL RESPONSES WITH LOW TKIS SENSITIVITY. FURTHERMORE, RESIDUAL LEUKEMIC STEM CELLS (LSCS) ARE INVOLVED IN THE MOLECULAR RELAPSE AFTER TKIS DISCONTINUATION. ABERRANT DNA HYPERMETHYLATION CONTRIBUTES TO LOW TKIS SENSITIVITY AND THE PERSISTENCE OF LSCS IN CML. DNMT1 IS A KEY REGULATOR OF HEMATOPOIETIC STEM CELLS, SUGGESTING THAT ABERRANT DNA HYPERMETHYLATION TARGETING DNMT1 REPRESENTS A POTENTIAL THERAPEUTIC TARGET FOR CML. WE INVESTIGATED THE EFFICACY OF OR-2100 (OR21), THE FIRST ORALLY AVAILABLE SINGLE-COMPOUND PRODRUG OF DECITABINE. OR21 EXHIBITED ANTI-TUMOR EFFECTS AS A MONOTHERAPY, AND IN COMBINATION THERAPY IT INCREASED TKI-INDUCED APOPTOSIS AND INDUCTION OF TUMOR SUPPRESSOR GENES INCLUDING PTPN6 ENCODING SHP-1 IN CML CELLS. OR21 IN COMBINATION WITH IMATINIB SIGNIFICANTLY SUPPRESSED TUMOR GROWTH IN A XENOTRANSPLANT MODEL. OR21 AND COMBINATION THERAPY DECREASED THE ABUNDANCE OF LSCS AND INHIBITED ENGRAFTMENT IN A BCR-ABL1-TRANSDUCED MOUSE MODEL. THESE RESULTS DEMONSTRATE THAT TARGETING DNMT1 USING OR21 EXERTS ANTI-TUMOR EFFECTS AND IMPAIRS LSCS IN CML. THEREFORE, COMBINATION TREATMENT OF TKIS AND OR21 REPRESENTS A PROMISING TREATMENT STRATEGY IN CML. 2022 4 1108 18 COMMENTARY ON SOME RECENT THESES RELEVANT TO COMBATING AGING: JUNE 2021. THESES REVIEWED IN THIS ISSUE INCLUDE "ENGINEERING PROTEIN DISAGGREGASES TO COUNTER ALPHA-SYNUCLEIN AND AMYLOID-BETA NEUROTOXICITY," "HYPERGLYCAEMIA INDUCED IMMUNOMODULATION OF MACROPHAGES IN DIABETIC VASCULAR DISEASE," "MICROVASCULATURE-ON-A-CHIP SYSTEMS FOR HUMAN DISEASE MODELING," "SENESCENCE SURVEILLANCE: THE INTERPLAY BETWEEN THE IMMUNE SYSTEM AND SENESCENT CELLS," "THE HMG TRANSCRIPTION FACTOR TOX INDUCES A TRANSCRIPTIONAL AND EPIGENETIC PROGRAM OF CD8(+) T CELL EXHAUSTION IN CHRONIC INFECTION AND CANCER," AND "ZERO TO ONE-TRANSLATIONAL ADVANCEMENTS IN THE FIELD OF XENOTRANSPLANTATION." 2021 5 2134 32 EPIGENETIC INACTIVATION OF THE MIR129-2 IN HEMATOLOGICAL MALIGNANCIES. BACKGROUND: MIR129-2 HAS BEEN SHOWN TO BE A TUMOR SUPPRESSOR MICRORNA HYPERMETHYLATED IN EPITHELIAL CANCERS. PATIENTS AND METHODS: EPIGENETIC INACTIVATION OF MIR129-2 WAS STUDIED BY METHYLATION-SPECIFIC PCR (MSP) IN 13 CELL LINES (EIGHT MYELOMA AND FIVE LYMPHOMA), 15 NORMAL CONTROLS AND 344 PRIMARY SAMPLES INCLUDING ACUTE MYELOID LEUKEMIA (AML), ACUTE LYMPHOBLASTIC LEUKEMIA (ALL), CHRONIC MYELOID LEUKEMIA (CML), CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), NON-HODGKIN'S LYMPHOMA (NHL), MULTIPLE MYELOMA (MM) AT DIAGNOSIS, MM AT RELAPSE/PROGRESSION, AND MONOCLONAL GAMMOPATHY OF UNDETERMINED SIGNIFICANCE (MGUS). EXPRESSION OF MIR129 AND ITS TARGET, SOX4, IN CELL LINES WAS MEASURED BEFORE AND AFTER HYPOMETHYLATING TREATMENT AND MIR129 OVEREXPRESSION. MIR129 EXPRESSION WAS CORRELATED WITH MIR129-2 METHYLATION STATUS IN PRIMARY LYMPHOMA SAMPLES. TUMOR SUPPRESSOR FUNCTION OF MIR129 WAS DEMONSTRATED BY MTT AND TRYPAN BLUE EXCLUSION ASSAY AFTER MIR129 OVEREXPRESSION. RESULTS: THE SENSITIVITY OF THE METHYLATED-MSP WAS ONE IN 10(3). DIFFERENT MSP STATUSES, INCLUDING COMPLETE METHYLATION, PARTIAL METHYLATION, AND COMPLETE UNMETHYLATION, WERE VERIFIED BY QUANTITATIVE BISULFITE PYROSEQUENCING. ALL FIVE LYMPHOMA AND SEVEN OF EIGHT MYELOMA CELL LINES SHOWED COMPLETE AND PARTIAL MIR129-2 METHYLATION. IN PRIMARY SAMPLES, MIR129-2 METHYLATION WAS ABSENT IN AML AND CML, BUT DETECTED IN 5% ALL, 45.9% CLL, 49.5% MM AT DIAGNOSIS, AND 59.1% NHL. IN CLL, MIR129-2 METHYLATION ADVERSELY IMPACTED ON SURVIVAL (P=0.004). IN MM, MIR129-2 METHYLATION INCREASED FROM 27.5% MGUS TO 49.5% MM AT DIAGNOSIS AND 41.5% AT RELAPSE/PROGRESSION (P=0.023). IN NHL, MIR129-2 METHYLATION WAS ASSOCIATED WITH MIR124-1 AND MIR203 METHYLATION (P<0.001), AND LOWER MIR129 EXPRESSION (P=0.009). HYPOMETHYLATION TREATMENT OF JEKO-1, HOMOZYGOUSLY METHYLATED FOR MIR129-2, LED TO MIR129-2 DEMETHYLATION AND MIR129 RE-EXPRESSION, WITH DOWNREGULATION OF SOX4 MRNA. MOREOVER, MIR129 OVEREXPRESSION IN BOTH MANTLE CELL LINES, JEKO-1 AND GRANTA-519, INHIBITED CELLULAR PROLIFERATION AND ENHANCED CELL DEATH, WITH CONCOMITANT SOX4 MRNA DOWNREGULATION. CONCLUSIONS: MIR129-2 IS A TUMOR SUPPRESSIVE MICRORNA FREQUENTLY METHYLATED IN LYMPHOID BUT NOT MYELOID MALIGNANCIES, LEADING TO REVERSIBLE MIR129-2 SILENCING. IN CLL, MIR129-2 METHYLATION WAS ASSOCIATED WITH AN INFERIOR SURVIVAL. IN MM, MIR129-2 METHYLATION MIGHT BE ACQUIRED DURING PROGRESSION FROM MGUS TO SYMPTOMATIC MM. IN NHL, MIR129-2 METHYLATION MIGHT COLLABORATE WITH MIR124-1 AND MIR203 METHYLATION IN LYMPHOMAGENESIS. 2013 6 5775 38 SPERMIDINE/SPERMINE N(1)-ACETYLTRANSFERASE ACTIVITY ASSOCIATES WITH WHITE BLOOD CELL COUNT IN MYELOID LEUKEMIAS. THE METABOLISM OF POLYAMINES, THE CATIONIC SMALL MOLECULES ESSENTIAL FOR CELL PROLIFERATION AND DIFFERENTIATION, IS ALTERED IN CANCER CELLS AND CAN BE EXPLOITED IN CANCER DIAGNOSIS AND THERAPY. SPERMIDINE/SPERMINE N(1)-ACETYLTRANSFERASE (SSAT), WHICH REGULATES INTRACELLULAR LEVELS OF POLYAMINES BY CATABOLIZING SPERMIDINE AND SPERMINE, HAS A CONTROVERSIAL ROLE IN THE DEVELOPMENT OF CANCERS. IN THIS STUDY, THE POLYAMINE METABOLISM AND FUNCTION OF SSAT WERE CHARACTERIZED IN ACUTE MYELOID LEUKEMIA (AML), CHRONIC MYELOID LEUKEMIA (CML), AND ACUTE LYMPHOID LEUKEMIA PATIENT SAMPLES. ALSO, MICE OVEREXPRESSING SSAT AND HAVING A MYELOPROLIFERATIVE PHENOTYPE WERE ANALYZED FOR THEIR RESPONSE TO DECITABINE AND HISTONE DEACETYLASE INHIBITOR TRICHOSTATIN A. THE PRESENCE OF EPIGENETIC FACTORS IN THE BONE MARROW CELLS OF SSAT MICE WAS ANALYZED. ELEVATED LEVELS OF SPERMIDINE AND SPERMINE, AS WELL AS INCREASED ACTIVITY OF SSAT, WERE DETECTED IN AML, CML, AND ACUTE LYMPHOID LEUKEMIA PATIENTS COMPARED WITH THE CONTROLS. HOWEVER, WE FOUND SSAT ACTIVITY TO BE ASSOCIATED WITH WHITE BLOOD CELL COUNT ONLY IN AML AND CML PATIENTS. DECITABINE TREATMENT BROUGHT THE PERIPHERAL BLOOD AND BONE MARROW CELL COUNTS OF SSAT MICE TO THE LEVEL OF WILD-TYPE MICE. SPERMIDINE/SPERMINE N(1)-ACETYLTRANSFERASE MICE HAD INCREASED HISTONE METHYLATION AND AN INCREASED LEVEL OF HISTONE DEACETYLASE 1 IN THEIR BONE MARROW CELLS. THE STUDY SUGGESTS THAT SSAT INFLUENCES THE DEVELOPMENT OF MYELOID MALIGNANCIES, AND EPIGENETIC FACTORS PARTLY CONTRIBUTE TO THE SSAT OVEREXPRESSION-INDUCED MYELOPROLIFERATIVE DISEASE IN MICE. 2014 7 1286 31 DECITABINE IN COMBINATION WITH DONOR LYMPHOCYTE INFUSIONS CAN INDUCE REMISSIONS IN RELAPSED MYELOID MALIGNANCIES WITH HIGHER LEUKEMIC BURDEN AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION. THE COMBINATION OF 5-AZACYTIDINE (AZA) WITH DONOR LYMPHOCYTE INFUSIONS (DLIS) CAN INDUCE REMISSIONS IN PATIENTS WITH RELAPSED MYELOID MALIGNANCIES AFTER ALLO-HCT. AS DECITABINE (DAC) IS KNOWN TO BE EFFECTIVE ALSO IN AML/MDS WITH LEUKOCYTOSIS, WE INVESTIGATED THE COMBINATION OF DAC WITH DLIS FOR RELAPSE AFTER ALLO-HCT. BETWEEN 2006 AND 2016, 26 PATIENTS (MEDIAN AGE 59 YEARS) WITH AML (N = 18), MDS (N = 6), OR MPN (N = 2) AND OVERT HEMATOLOGICAL RELAPSE AFTER ALLO-HCT WERE TREATED. MEDIAN DURATION FROM ALLO-HCT TO RELAPSE WAS 306 DAYS (RANGE, 76-4943). EIGHTEEN PATIENTS RECEIVED DAC + DLIS, 8 DAC-ONLY (MEDIAN NUMBER CYCLES OF DAC: 2, RANGE 1-13, MEDIAN NUMBER OF DLIS: 2, RANGE 1-10). THE INCIDENCE OF ACUTE AND CHRONIC GVHD IN PATIENTS RECEIVING DLI WAS 17% (3/18) AND 6% (1/18), RESPECTIVELY. CR/CRI WAS ACHIEVED IN 15% (4/26), PR IN 4% (1/26), AND STABLE DISEASE IN 58% (15/26) OF PATIENTS. EIGHT PATIENTS RECEIVED A SECOND ALLO-HCT. MEDIAN OVERALL SURVIVAL WAS 4.7 MONTHS. ELEVATED PD-L1 PROTEIN EXPRESSION IN BONE MARROW CELLS WAS DETECTED IN 4/8 PATIENTS WITH >20% BLAST INFILTRATION PRIOR TO DAC, WITHOUT A CLEAR ASSOCIATION WITH RESPONSE. IN CONCLUSION, THE DAC + DLI REGIMEN PROVED FEASIBLE AND EFFECTIVE IN RELAPSED MYELOID MALIGNANCIES AFTER ALLO-HCT, WITH EFFICACY NOT RESTRICTED TO PATIENTS WITH LOW LEUKEMIC BURDEN. 2018 8 4005 31 LOSS OF THE TUMOR SUPPRESSOR BAP1 CAUSES MYELOID TRANSFORMATION. DE-UBIQUITINATING ENZYME BAP1 IS MUTATED IN A HEREDITARY CANCER SYNDROME WITH INCREASED RISK OF MESOTHELIOMA AND UVEAL MELANOMA. SOMATIC BAP1 MUTATIONS OCCUR IN VARIOUS MALIGNANCIES. WE SHOW THAT MOUSE BAP1 GENE DELETION IS LETHAL DURING EMBRYOGENESIS, BUT SYSTEMIC OR HEMATOPOIETIC-RESTRICTED DELETION IN ADULTS RECAPITULATES FEATURES OF HUMAN MYELODYSPLASTIC SYNDROME (MDS). KNOCKIN MICE EXPRESSING BAP1 WITH A 3XFLAG TAG REVEALED THAT BAP1 INTERACTS WITH HOST CELL FACTOR-1 (HCF-1), O-LINKED N-ACETYLGLUCOSAMINE TRANSFERASE (OGT), AND THE POLYCOMB GROUP PROTEINS ASXL1 AND ASXL2 IN VIVO. OGT AND HCF-1 LEVELS WERE DECREASED BY BAP1 DELETION, INDICATING A CRITICAL ROLE FOR BAP1 IN STABILIZING THESE EPIGENETIC REGULATORS. HUMAN ASXL1 IS MUTATED FREQUENTLY IN CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) SO AN ASXL/BAP1 COMPLEX MAY SUPPRESS CMML. A BAP1 CATALYTIC MUTATION FOUND IN A MDS PATIENT IMPLIES THAT BAP1 LOSS OF FUNCTION HAS SIMILAR CONSEQUENCES IN MICE AND HUMANS. 2012 9 4553 37 MUTATIONAL LANDSCAPE OF CHRONIC MYELOMONOCYTIC LEUKEMIA IN CHINESE PATIENTS. BACKGROUND: CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A RARE AND HETEROGENEOUS HEMATOLOGICAL MALIGNANCY. IT HAS BEEN SHOWN THAT THE MOLECULAR ABNORMALITIES SUCH AS ASXL1, TET2, SETBP1, AND SRSF2 MUTATIONS ARE COMMON IN CAUCASIAN POPULATION. METHODS: WE RETROSPECTIVELY ANALYZED 178 CHINESE CMML PATIENTS. THE TARGETED NEXT GENERATION SEQUENCING (NGS) WAS USED TO EVALUATE 114 GENE VARIATIONS, AND THE PROGNOSTIC FACTORS FOR OS WERE DETERMINED BY COX REGRESSION ANALYSIS. RESULTS: THE CMML PATIENTS SHOWED A UNIQUE MUTATIONAL SPECTRUM, INCLUDING TET2 (36.5%), NRAS (31.5%), ASXL1 (28.7%), SRSF2 (24.7%), AND RUNX1 (21.9%). OF THE 102 PATIENTS WITH CLONAL ANALYSIS, THE ANCESTRAL EVENTS PREFERENTIALLY OCCURRED IN TET2 (18.5%), SPLICING FACTORS (16.5%), RAS (14.0%), AND ASXL1 (7.8%), AND THE SUBCLONAL GENES WERE MAINLY ASXL1, TET2, AND RAS. IN ADDITION, THE SECONDARY ACUTE MYELOID LEUKEMIA (SAML) TRANSFORMED FROM CMML OFTEN HAD MUTATIONS IN DNMT3A, ETV6, FLT3, AND NPM1, WHILE THE PRIMARY AML (PAML) DEMONSTRATED MORE MUTATIONS IN CEBPA, DNMT3A, FLT3, IDH1/2, NPM1, AND WT1. IT WAS OF NOTE THAT A SERIES OF CLONES WERE EMERGED DURING THE PROGRESSION FROM CMML TO AML, INCLUDING DNMT3A, FLT3, AND NPM1. BY UNIVARIATE ANALYSIS, ASXL1 MUTATION, INTERMEDIATE- AND HIGH-RISK CYTOGENETIC ABNORMALITY, CMML-SPECIFIC PROGNOSTIC SCORING SYSTEM (CPSS) STRATIFICATIONS (INTERMEDIATE-2 AND HIGH GROUP), AND TREATMENT OPTIONS (BEST SUPPORTIVE CARE) PREDICTED FOR WORSE OS. MULTIVARIATE ANALYSIS REVEALED A SIMILAR OUTCOME. CONCLUSIONS: THE COMMON MUTATIONS IN CHINESE CMML PATIENTS INCLUDED EPIGENETIC MODIFIERS (TET2 AND ASXL1), SIGNALING TRANSDUCTION PATHWAY COMPONENTS (NRAS), AND SPLICING FACTOR (SRSF2). THE CMML PATIENTS WITH DNMT3A, ETV6, FLT3, AND NPM1 MUTATIONS TENDED TO PROGRESS TO SAML. ASXL1 MUTATION AND THERAPEUTIC MODALITIES WERE INDEPENDENT PROGNOSTIC FACTORS FOR CMML. 2022 10 3871 26 JUVENILE MYELOMONOCYTIC LEUKEMIA - A BONA FIDE RASOPATHY SYNDROME. JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) IS A PEDIATRIC MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASM OVERLAP SYNDROME WITH SUSTAINED PERIPHERAL BLOOD MONOCYTOSIS, AGGRESSIVE FEATURES, AND POOR OUTCOMES. IN >90% OF CASES JMML IS DRIVEN BY GERMLINE OR SOMATIC MUTATIONS INVOLVING THE CANONICAL RAS PATHWAY (PTPN11, NRAS, CBL, KRAS AND NF1), WITH SOMATIC MUTATIONS/ALTERATIONS IN RAS PATHWAY GENES (SECOND HIT), SETBP1, ASXL1 AND JAK3 RESULTING IN DISEASE PROGRESSION. WHILE SPONTANEOUS REGRESSION HAS BEEN SEEN IN GERMLINE PTPN11 AND CBL MUTANT JMML, IN MOST PATIENTS, ALLOGENEIC STEM CELL TRANSPLANT IS THE ONLY CURATIVE MODALITY. JMML SHARES SEVERAL PHENOTYPIC FEATURES WITH ITS ADULT COUNTERPART PROLIFERATIVE, CHRONIC MYELOMONOCYTIC LEUKEMIA (PCMML). PCMML LARGELY OCCURS DUE TO RAS PATHWAY MUTATIONS THAT OCCUR IN THE CONTEXT OF AGE RELATED CLONAL HEMATOPOIESIS (TET2, SRSF2, ASXL1), WHILE JMML IS A BONA FIDE RASOPATHY, WITH ADDITIONAL SOMATIC MUTATIONS, INCLUDING IN EPIGENETIC REGULATORS GENES RESULTING IN DISEASE PROGRESSION. 2020 11 829 30 CHARACTERIZATION OF P190-BCR-ABL CHRONIC MYELOID LEUKEMIA REVEALS SPECIFIC SIGNALING PATHWAYS AND THERAPEUTIC TARGETS. THE ONCOGENIC PROTEIN BCR-ABL HAS TWO MAJOR ISOFORMS, P190(BCR-ABL) AND P210(BCR-ABL). WHILE P210(BCR-ABL) IS THE HALLMARK OF CHRONIC MYELOID LEUKEMIA (CML), P190(BCR-ABL) OCCURS IN THE MAJORITY OF PHILADELPHIA-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA (PH + ALL) PATIENTS. IN CML, P190(BCR-ABL) OCCURS IN A MINORITY OF PATIENTS ASSOCIATING WITH DISTINCT HEMATOLOGICAL FEATURES AND INFERIOR OUTCOMES, YET THE PATHOGENIC ROLE OF P190(BCR-ABL) AND POTENTIAL TARGETING THERAPIES ARE LARGELY UNCHARACTERIZED. WE EMPLOYED NEXT GENERATION SEQUENCING, PHOSPHO-PROTEOMIC PROFILING, AND DRUG SENSITIVITY TESTING TO CHARACTERIZE P190(BCR-ABL) IN CML AND HEMATOPOIETIC PROGENITOR CELL LINE MODELS (BA/F3 AND HPC-LSK). P190(BCR-ABL) CML PATIENTS DEMONSTRATED POOR RESPONSE TO IMATINIB AND FREQUENT MUTATIONS IN EPIGENETIC MODIFIERS GENES. IN CONTRAST WITH P210(BCR-ABL), P190(BCR-ABL) EXHIBITED SPECIFIC TRANSCRIPTIONAL UPREGULATION OF INTERFERON, INTERLEUKIN-1 RECEPTOR, AND P53 SIGNALING PATHWAYS, ASSOCIATED WITH HYPERPHOSPHORYLATION OF RELEVANT SIGNALING MOLECULES INCLUDING JAK1/STAT1 AND PAK1 IN ADDITION TO SRC HYPERPHOSPHORYLATION. COMPARABLE TO P190(BCR-ABL) CML PATIENTS, P190(BCR-ABL) CELL LINES DEMONSTRATED SIMILAR TRANSCRIPTIONAL AND PHOSPHO-SIGNALING SIGNATURES. WITH THE DRUG SENSITIVITY SCREENING WE IDENTIFIED TARGETED DRUGS WITH SPECIFIC ACTIVITY IN P190(BCR-ABL) CELL LINES INCLUDING IAP-, PAK1-, AND SRC INHIBITORS AND GLUCOCORTICOIDS. OUR RESULTS PROVIDE NOVEL INSIGHTS INTO THE MECHANISMS UNDERLYING THE DISTINCT FEATURES OF P190(BCR-ABL) CML AND PROMISING THERAPEUTIC TARGETS FOR THIS HIGH-RISK PATIENT GROUP. 2021 12 4556 29 MUTATIONAL SPECTRUM OF MYELOID MALIGNANCIES WITH INV(3)/T(3;3) REVEALS A PREDOMINANT INVOLVEMENT OF RAS/RTK SIGNALING PATHWAYS. MYELOID MALIGNANCIES BEARING CHROMOSOMAL INV(3)/T(3;3) ABNORMALITIES ARE AMONG THE MOST THERAPY-RESISTANT LEUKEMIAS. DEREGULATED EXPRESSION OF EVI1 IS THE MOLECULAR HALLMARK OF THIS DISEASE; HOWEVER, THE GENOME-WIDE SPECTRUM OF COOPERATING MUTATIONS IN THIS DISEASE SUBSET HAS NOT BEEN SYSTEMATICALLY ELUCIDATED. HERE, WE SHOW THAT 98% OF INV(3)/T(3;3) MYELOID MALIGNANCIES HARBOR MUTATIONS IN GENES ACTIVATING RAS/RECEPTOR TYROSINE KINASE (RTK) SIGNALING PATHWAYS. IN ADDITION, HEMIZYGOUS MUTATIONS IN GATA2, AS WELL AS HETEROZYGOUS ALTERATIONS IN RUNX1, SF3B1, AND GENES ENCODING EPIGENETIC MODIFIERS, FREQUENTLY CO-OCCUR WITH THE INV(3)/T(3;3) ABERRATION. NOTABLY, NEITHER MUTATIONAL PATTERNS NOR GENE EXPRESSION PROFILES DIFFER ACROSS INV(3)/T(3;3) ACUTE MYELOID LEUKEMIA, CHRONIC MYELOID LEUKEMIA, AND MYELODYSPLASTIC SYNDROME CASES, SUGGESTING RECOGNITION OF INV(3)/T(3;3) MYELOID MALIGNANCIES AS A SINGLE DISEASE ENTITY IRRESPECTIVE OF BLAST COUNT. THE HIGH INCIDENCE OF ACTIVATING RAS/RTK SIGNALING MUTATIONS MAY PROVIDE A TARGET FOR A RATIONAL TREATMENT STRATEGY IN THIS HIGH-RISK PATIENT GROUP. 2015 13 6028 24 THE BMI1 POLYCOMB PROTEIN REPRESSES CYCLIN G2-INDUCED AUTOPHAGY TO SUPPORT PROLIFERATION IN CHRONIC MYELOID LEUKEMIA CELLS. THE BMI1 POLYCOMB PROTEIN REGULATES SELF-RENEWAL, PROLIFERATION AND SURVIVAL OF CANCER-INITIATING CELLS ESSENTIALLY THROUGH EPIGENETIC REPRESSION OF THE CDKN2A TUMOR SUPPRESSOR LOCUS. WE DEMONSTRATE HERE FOR THE FIRST TIME THAT BMI1 ALSO PREVENTS AUTOPHAGY IN CHRONIC MYELOID LEUKEMIA (CML) CELL LINES, TO SUPPORT THEIR PROLIFERATION AND CLONOGENIC ACTIVITY. USING CHROMATIN IMMUNOPRECIPITATION, WE IDENTIFIED CCNG2/CYCLIN G2 (CCNG2) AS A DIRECT BMI1 TARGET. BMI1 DOWNREGULATION IN CD34+ CML CELLS BY PTC-209 PHARMACOLOGICAL TREATMENT OR SHBMI1 TRANSDUCTION TRIGGERED CCNG2 EXPRESSION AND DECREASED CLONOGENIC ACTIVITY. ALSO, ECTOPIC EXPRESSION OF CCNG2 IN CD34+ CML CELLS STRONGLY DECREASED THEIR CLONOGENICITY. CCNG2 WAS SHOWN TO ACT BY DISRUPTING THE PHOSPHATASE 2A COMPLEX, WHICH ACTIVATES A PKCZETA-AMPK-JNK-ERK PATHWAY THAT ENGAGES AUTOPHAGY. WE OBSERVED THAT BMI1 AND CCNG2 LEVELS EVOLVED INVERSELY DURING THE PROGRESSION OF CML TOWARDS AN ACUTE DEADLY PHASE, AND THEREFORE HYPOTHESIZED THAT BMI1 COULD SUPPORT ACUTE TRANSFORMATION OF CML THROUGH THE SILENCING OF A CCNG2-MEDIATED TUMOR-SUPPRESSIVE AUTOPHAGY RESPONSE. 2015 14 3009 30 GENETICS AND EPIGENETICS IN NEOPLASMS WITH PLASMACYTOID DENDRITIC CELLS. PLASMACYTOID DENDRITIC CELLS (PDC) ARE TYPE I INTERFERON (IFN)-PRODUCING CELLS THAT PLAY A KEY ROLE IN IMMUNE RESPONSES. TWO MAJOR TYPES OF NEOPLASTIC COUNTERPARTS FOR PDC ARE NOW DISCRIMINATED: BLASTIC PDC NEOPLASM (BPDCN) AND MATURE PDC PROLIFERATION (MPDCP), ASSOCIATED WITH MYELOID NEOPLASM. TWO TYPES OF MPDCP ARE NOW BETTER DESCRIBED: CHRONIC MYELOMONOCYTIC LEUKEMIA WITH PDC EXPANSION (PDC-CMML) AND ACUTE MYELOID LEUKEMIA WITH PDC EXPANSION (PDC-AML). DIFFERENTIAL DIAGNOSIS BETWEEN PDC-AML AND BPDCN IS PARTICULARLY CHALLENGING, AND GENOMIC FEATURES CAN HELP FOR DIAGNOSIS. HERE, WE SYSTEMATICALLY REVIEW THE CYTOGENETIC, MOLECULAR, AND TRANSCRIPTIONAL CHARACTERISTICS OF BPDCN AND PDC-AML. BPDCN ARE CHARACTERIZED BY FREQUENT COMPLEX KARYOTYPES WITH RECURRENT MYB/MYC REARRANGEMENTS AS WELL AS RECURRENT DELETIONS INVOLVING ETV6, IKZF1, RB1, AND TP53 LOCI. EPIGENETIC AND SPLICING PATHWAYS ARE ALSO PARTICULARLY MUTATED, WHILE ORIGINAL PROCESSES ARE DYSREGULATED, SUCH AS NF-KB, TCF4, BCL2, AND IFN PATHWAYS; NEUTROPHIL-SPECIFIC RECEPTORS; AND CHOLINERGIC SIGNALING. IN CONTRAST, CYTOGENETIC ABNORMALITIES ARE LIMITED IN PDC-AML AND ARE QUITE SIMILAR TO OTHER AML. INTERESTINGLY, RUNX1 IS THE MOST FREQUENTLY MUTATED GENE (70% OF CASES). THESE TYPICAL GENOMIC FEATURES ARE OF POTENTIAL INTEREST FOR DIAGNOSIS, AND ALSO FROM A PROGNOSTIC OR THERAPEUTIC PERSPECTIVE. 2022 15 3484 53 IDENTIFICATION OF CHROMATIN REMODELING GENES ARID4A AND ARID4B AS LEUKEMIA SUPPRESSOR GENES. BACKGROUND: LEUKEMIA EVOLVES THROUGH A MULTISTEP PROCESS FROM PREMALIGNANCY TO MALIGNANCY. EPIGENETIC ALTERATIONS, INCLUDING HISTONE MODIFICATIONS, HAVE BEEN PROPOSED TO PLAY AN IMPORTANT ROLE IN TUMORIGENESIS. THE INVOLVEMENT OF TWO CHROMATIN REMODELING GENES, RETINOBLASTOMA-BINDING PROTEIN 1 (RBBP1/ARID4A) AND RBBP1-LIKE 1 (RBBP1L1/ARID4B), IN LEUKEMOGENESIS WAS NOT CHARACTERIZED. METHODS: THE LEUKEMIC PHENOTYPE OF MICE DEFICIENT FOR ARID4A WITH OR WITHOUT HAPLOINSUFFICIENCY FOR ARID4B WAS INVESTIGATED BY SERIALLY MONITORING COMPLETE BLOOD COUNTS TOGETHER WITH MICROSCOPIC HISTOLOGIC ANALYSIS AND FLOW CYTOMETRIC ANALYSIS OF BONE MARROW AND SPLEEN FROM THE ARID4A(-/-) MICE OR ARID4A(-/-)ARID4B(+/-) MICE. REGULATION IN BONE MARROW CELLS OF DOWNSTREAM GENES IMPORTANT FOR NORMAL HEMATOPOIESIS WAS ANALYZED BY REVERSE TRANSCRIPTION-POLYMERASE CHAIN REACTION. GENOTYPIC EFFECTS ON HISTONE MODIFICATIONS WERE EXAMINED BY WESTERN BLOTTING AND IMMUNOFLUORESCENCE ANALYSIS. ALL STATISTICAL TESTS WERE TWO-SIDED. RESULTS: YOUNG (2-5 MONTHS OLD) ARID4A-DEFICIENT MICE HAD INEFFECTIVE BLOOD CELL PRODUCTION IN ALL HEMATOPOIETIC LINEAGES. BEYOND 5 MONTHS OF AGE, THE ARID4A(-/-) MICE MANIFESTED MONOCYTOSIS, ACCOMPANIED BY SEVERE ANEMIA AND THROMBOCYTOPENIA. THESE SICK ARID4A(-/-) MICE SHOWED BONE MARROW FAILURE WITH MYELOFIBROSIS ASSOCIATED WITH SPLENOMEGALY AND HEPATOMEGALY. FIVE OF 42 ARID4A(-/-) MICE AND 10 OF 12 ARID4A(-/-)ARID4B(+/-) MICE PROGRESSED TO ACUTE MYELOID LEUKEMIA (AML) AND HAD RAPID FURTHER INCREASES OF LEUKOCYTE COUNTS. EXPRESSION OF HOX GENES (HOXB3, HOXB5, HOXB6, AND HOXB8) WAS DECREASED IN ARID4A-DEFICIENT BONE MARROW CELLS WITH OR WITHOUT ARID4B HAPLOINSUFFICIENCY, AND FOXP3 EXPRESSION WAS REDUCED IN ARID4A(-/-)ARID4B(+/-) BONE MARROW. INCREASES OF HISTONE TRIMETHYLATION OF H3K4, H3K9, AND H4K20 (FOLD INCREASES IN TRIMETHYLATION = 32, 95% CONFIDENCE INTERVAL [CI] = 27 TO 32; 45, 95% CI = 41 TO 49; AND 2.2, 95% CI = 1.7 TO 2.7, RESPECTIVELY) WERE OBSERVED IN THE BONE MARROW OF ARID4A-DEFICIENT MICE. CONCLUSIONS: ARID4A-DEFICIENT MICE INITIALLY DISPLAY INEFFECTIVE HEMATOPOIESIS, FOLLOWED BY TRANSITION TO CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML)-LIKE MYELODYSPLASTIC/MYELOPROLIFERATIVE DISORDER, AND THEN TRANSFORMATION TO AML. THE DISEASE PROCESSES IN THE ARID4A-DEFICIENT MICE ARE VERY SIMILAR TO THE COURSE OF EVENTS IN HUMANS WITH CMML AND AML. THIS MOUSE MODEL HAS THE POTENTIAL TO FURNISH ADDITIONAL INSIGHTS INTO THE ROLE OF EPIGENETIC ALTERATIONS IN LEUKEMOGENESIS, AND IT MAY BE USEFUL IN DEVELOPING NOVEL PHARMACOLOGICAL APPROACHES TO TREATMENT OF PRELEUKEMIC AND LEUKEMIC STATES. 2008 16 2887 22 GADD45A TRANSCRIPTIONAL INDUCTION ELICITED BY THE AURORA KINASE INHIBITOR MK-0457 IN BCR-ABL-EXPRESSING CELLS IS DRIVEN BY OCT-1 TRANSCRIPTION FACTOR. THE ADVANTAGE OF AURORA KINASE (AK) INHIBITORS IN CHRONIC MYELOID LEUKEMIA (CML) THERAPY MOSTLY ARISES FROM "OFF-TARGET" EFFECTS ON TYROSINE KINASE (TK) ACTIVITY OF WILD TYPE (WT) OR MUTATED BCR-ABL PROTEINS WHICH DRIVE THE DISEASE RESISTANCE TO IMATINIB (IM). WE PROVED THAT THE AK INHIBITOR MK-0457 INDUCES THE GROWTH ARREST DNA DAMAGE-INDUCIBLE (GADD) 45A THROUGH RECRUITMENT OF OCTAMER-BINDING (OCT)-1 TRANSCRIPTION FACTOR AT A CRITICAL PROMOTER REGION FOR GENE TRANSCRIPTION AND COVALENT MODIFICATIONS OF HISTONE H3 (LYSINE 14 ACETYLATION, LYSINE 9 DE-METHYLATION). SUCH EPIGENETIC CHROMATIN MODIFICATIONS MAY DEPICT A GENERAL MECHANISM PROMOTING THE RE-ACTIVATION OF TUMOR SUPPRESSOR GENES SILENCED BY BCR-ABL. 2012 17 5861 36 SUPER-ENHANCER LANDSCAPE REVEALS LEUKEMIA STEM CELL RELIANCE ON X-BOX BINDING PROTEIN 1 AS A THERAPEUTIC VULNERABILITY. RELAPSE OF PATIENTS WITH CHRONIC MYELOGENOUS LEUKEMIA (CML) MAY OCCUR AT LEAST PARTIALLY BECAUSE LEUKEMIA STEM CELLS (LSCS) LACK SENSITIVITY TO TYROSINE KINASE INHIBITORS (TKIS) SUCH AS IMATINIB. THE PRECISE REGULATION OF LSC STEMNESS IS INCOMPLETELY UNDERSTOOD. GIVEN THAT TRAITS OF LSCS ARE SUBJECT TO EPIGENETIC REGULATION, WE HYPOTHESIZED THAT LSCS MIGHT BE DEPENDENT ON CONTINUOUS ACTIVE TRANSCRIPTION OF GENES ASSOCIATED WITH SUPER-ENHANCERS (SES), WHICH MIGHT, IN TURN, SUGGEST AN OPPORTUNITY FOR INTERVENTION. IN THIS STUDY, WE TESTED THIS HYPOTHESIS AND DELINEATED THE SE LANDSCAPE IN LSCS FROM PATIENTS WITH CML. DISRUPTION OF THE SE-ASSOCIATED GENE TRANSCRIPTION BY THZ1, A COVALENT CYCLIN-DEPENDENT KINASE 7 (CDK7) INHIBITOR, EFFICIENTLY ERADICATED LSCS IN RETROVIRAL BCR-ABL-DRIVEN CML MICE WHILE SPARING NORMAL HEMATOPOIETIC STEM CELLS. FURTHERMORE, WE FOUND THAT X-BOX BINDING PROTEIN 1 (XBP1), A SUBSTRATE OF MRNA-SPLICING ENDONUCLEASE IRE1ALPHA IN THE UNFOLDED PROTEIN RESPONSE PATHWAY, WAS AN SE-ASSOCIATED ONCOGENE IN LSCS. KNOCKDOWN OF XBP1 REDUCED SURVIVAL AND SELF-RENEWAL CAPACITY IN PRIMARY CML CD34(+) CELLS AND ERADICATED LSCS IN CML MICE. SELECTIVELY BLOCKING GENERATION OF THE SPLICED FORM OF XBP1 BY HEMATOPOIETIC CELL-SPECIFIC IRE1 CONDITIONAL KNOCKOUT SUPPRESSED THE PROGRESSION OF CML AND IMPAIRED THE LEUKEMOGENESIS OF LSCS IN CML MICE. OVERALL, WE IDENTIFIED AN EPIGENETIC TRANSCRIPTIONAL PROGRAM IN LSCS, ADDING TO EVIDENCE FOR THE THEORY OF "ONCOGENE ADDICTION" AND SUGGESTING A POTENTIAL TARGETING STRATEGY FOR CML. 2021 18 2888 34 GAIN-OF-FUNCTION MUTATION OF GATA-2 IN ACUTE MYELOID TRANSFORMATION OF CHRONIC MYELOID LEUKEMIA. ACQUISITION OF ADDITIONAL GENETIC AND/OR EPIGENETIC ABNORMALITIES OTHER THAN THE BCR/ABL FUSION GENE IS BELIEVED TO CAUSE DISEASE PROGRESSION IN CHRONIC MYELOID LEUKEMIA (CML) FROM CHRONIC PHASE TO BLAST CRISIS (BC). TO GAIN INSIGHTS INTO THE UNDERLYING MECHANISMS OF PROGRESSION TO BC, WE SCREENED DNA SAMPLES FROM CML PATIENTS DURING BLAST TRANSFORMATION FOR MUTATIONS IN A NUMBER OF TRANSCRIPTION FACTOR GENES THAT ARE CRITICAL FOR MYELOID-LYMPHOID DEVELOPMENT. IN 85 CASES OF CML BLAST TRANSFORMATION, WE IDENTIFIED TWO NEW MUTATIONS IN THE CODING REGION OF GATA-2, A NEGATIVE REGULATOR OF HEMATOPOIETIC STEM/PROGENITOR CELL DIFFERENTIATION. A L359V SUBSTITUTION WITHIN ZINC FINGER DOMAIN (ZF) 2 OF GATA-2 WAS FOUND IN EIGHT CASES WITH MYELOMONOBLASTIC FEATURES, WHEREAS AN IN-FRAME DELETION OF 6 AA (DELTA341-346) SPANNING THE C-TERMINAL BORDER OF ZF1 WAS DETECTED IN ONE PATIENT AT MYELOID BC WITH EOSINOPHILIA. FURTHER STUDIES INDICATED THAT L359V NOT ONLY INCREASED TRANSACTIVATION ACTIVITY OF GATA-2 BUT ALSO ENHANCED ITS INHIBITORY EFFECTS ON THE ACTIVITY OF PU.1, A MAJOR REGULATOR OF MYELOPOIESIS. CONSISTENT WITH THE MYELOMONOBLASTIC FEATURES OF CML TRANSFORMATION WITH THE GATA-2 L359V MUTANT, TRANSDUCTION OF THE GATA-2 L359V MUTANT INTO HL-60 CELLS OR BCR/ABL-HARBORING MURINE CELLS DISTURBED MYELOMONOCYTIC DIFFERENTIATION/PROLIFERATION IN VITRO AND IN VIVO, RESPECTIVELY. THESE DATA STRONGLY SUGGEST THAT GATA-2 MUTATIONS MAY PLAY A ROLE IN ACUTE MYELOID TRANSFORMATION IN A SUBSET OF CML PATIENTS. 2008 19 5940 30 TARGETING METHYLTRANSFERASE PRMT5 ELIMINATES LEUKEMIA STEM CELLS IN CHRONIC MYELOGENOUS LEUKEMIA. IMATINIB-INSENSITIVE LEUKEMIA STEM CELLS (LSCS) ARE BELIEVED TO BE RESPONSIBLE FOR RESISTANCE TO BCR-ABL TYROSINE KINASE INHIBITORS AND RELAPSE OF CHRONIC MYELOGENOUS LEUKEMIA (CML). IDENTIFYING THERAPEUTIC TARGETS TO ERADICATE CML LSCS MAY BE A STRATEGY TO CURE CML. IN THE PRESENT STUDY, WE DISCOVERED A POSITIVE FEEDBACK LOOP BETWEEN BCR-ABL AND PROTEIN ARGININE METHYLTRANSFERASE 5 (PRMT5) IN CML CELLS. OVEREXPRESSION OF PRMT5 WAS OBSERVED IN HUMAN CML LSCS. SILENCING PRMT5 WITH SHRNA OR BLOCKING PRMT5 METHYLTRANSFERASE ACTIVITY WITH THE SMALL-MOLECULE INHIBITOR PJ-68 REDUCED SURVIVAL, SERIAL REPLATING CAPACITY, AND LONG-TERM CULTURE-INITIATING CELLS (LTC-ICS) IN LSCS FROM CML PATIENTS. FURTHER, PRMT5 KNOCKDOWN OR PJ-68 TREATMENT DRAMATICALLY PROLONGED SURVIVAL IN A MURINE MODEL OF RETROVIRAL BCR-ABL-DRIVEN CML AND IMPAIRED THE IN VIVO SELF-RENEWAL CAPACITY OF TRANSPLANTED CML LSCS. PJ-68 ALSO INHIBITED LONG-TERM ENGRAFTMENT OF HUMAN CML CD34+ CELLS IN IMMUNODEFICIENT MICE. MOREOVER, INHIBITION OF PRMT5 ABROGATED THE WNT/BETA-CATENIN PATHWAY IN CML CD34+ CELLS BY DEPLETING DISHEVELLED HOMOLOG 3 (DVL3). THIS STUDY SUGGESTS THAT EPIGENETIC METHYLATION MODIFICATION ON HISTONE PROTEIN ARGININE RESIDUES IS A REGULATORY MECHANISM TO CONTROL SELF-RENEWAL OF LSCS AND INDICATES THAT PRMT5 MAY REPRESENT A POTENTIAL THERAPEUTIC TARGET AGAINST LSCS. 2016 20 5934 31 TARGETING FEATURES OF CURAXIN CBL0137 ON HEMATOLOGICAL MALIGNANCIES IN VITRO AND IN VIVO. THE ANTICANCER ACTIVITY OF CURAXIN CBL0137, A DNA-BINDING SMALL MOLECULE WITH CHROMATIN REMODULATING EFFECT, HAS BEEN DEMONSTRATED IN DIFFERENT CANCERS. HEREIN, A COMPARATIVE EVALUATION OF CBL0137 ACTIVITY WAS PERFORMED IN RESPECT TO ACUTE MYELOID LEUKEMIA (AML), ACUTE LYMPHOBLASTIC LEUKEMIA (ALL), CHRONIC MYELOID LEUKEMIA AND MULTIPLE MYELOMA (MM) CULTURED IN VITRO. MTT ASSAY SHOWED AML AND MM HIGHER SENSITIVITY TO CBL0137'S CYTOSTATIC EFFECT COMPARATIVELY TO OTHER HEMATOLOGICAL MALIGNANCY CELLS. FLOW CYTOMETRY CELL CYCLE ANALYSIS REVEALED AN INCREASE IN SUBG1 AND G2/M POPULATIONS AFTER CBL0137 CELL TREATMENT, BUT THE PREVALENT TYPE OF ARREST VARIED. APOPTOSIS ACTIVATION BY CBL0137 MEASURED BY ANNEXIN-V/PI DUAL STAINING WAS MORE ACTIVE IN AML AND MM CELLS. RT2 PCR ARRAY SHOWED THAT CHANGES CAUSED BY CBL0137 IN SIGNALING PATHWAYS INVOLVED IN CANCER PATHOGENESIS WERE MORE INTENSIVE IN AML AND MM CELLS. ON THE MURINE MODEL OF AML WEHI-3, CBL0137 SHOWED SIGNIFICANT ANTICANCER EFFECTS IN VIVO, WHICH WERE EVALUATED BY CORRESPONDING CHANGES IN SPLEEN AND LIVER. THUS, MORE PRONOUNCED ANTICANCER EFFECTS OF CBL0137 IN VITRO WERE OBSERVED IN RESPECT TO AML AND MM. EXPERIMENTS IN VIVO ALSO INDICATED THE PERSPECTIVE OF CBL0137 USE FOR AML TREATMENT. THIS IN ACCORDANCE WITH THE FRONTLINE TREATMENT APPROACH IN AML USING EPIGENETIC DRUGS. 2023