1 5249 137 PROGRAMMED CELL DEATH-1 PATHWAY INHIBITION IN MYELOID MALIGNANCIES: IMPLICATIONS FOR MYELOPROLIFERATIVE NEOPLASMS. MYELOPROLIFERATIVE NEOPLASMS (MPNS) ARE CLONAL HEMATOPOIETIC DISEASES THAT BELONG TO THE SPECTRUM OF MYELOID MALIGNANCIES (MYMS), WHICH ALSO INCLUDE MYELODYSPLASTIC SYNDROMES (MDS), ACUTE MYELOID LEUKEMIA (AML), AND CHRONIC MYELOGENOUS LEUKEMIA (CML). WHILE HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) IS A POTENTIALLY CURATIVE THERAPEUTIC APPROACH TO MANY MYMS, THE ASSOCIATED MORBIDITY AND MORTALITY HAVE NECESSITATED THE DEVELOPMENT OF NON-HSCT THERAPEUTICS FOR SYMPTOM MANAGEMENT AND DISEASE COURSE MODIFICATION. IMMUNE CHECKPOINT INHIBITION, IN PARTICULAR ALONG THE PROGRAMMED CELL DEATH PROTEIN 1 (PD-1)/B7-H1 (PD-L1) AXIS, IS AN ESTABLISHED STRATEGY IN SOLID TUMORS WITH POTENTIAL AS AN ADJUNCTIVE THERAPY IN HEMATOLOGIC MALIGNANCIES. SEMINAL STUDIES SUGGEST THAT THE PRO-INFLAMMATORY MICROENVIRONMENT OF MYMS CAN SUPPRESS T LYMPHOCYTE-MEDIATED IMMUNITY VIA PD-1 SIGNALING AND THAT RESPONSE TO MAINSTAY EPIGENETIC THERAPIES FOR MYMS MAY BE GOVERNED BY PD-1 GENE REGULATION. ALTHOUGH THE ROLE OF PD-1 SIGNALING IN MPN PATHOGENESIS AND PROGRESSION IS AS YET UNCLEAR, RESEARCH IN MPN PATIENTS HAS REVEALED EXPANSION OF MYELOID-DERIVED SUPPRESSOR CELLS (MDSCS), WHICH MAY EFFECT HOST IMMUNE TOLERANCE OF TUMOR VIA TEMPORALLY AND SPATIALLY SPECIFIC ACTIVATION OF PD-1/PD-L1 SIGNALING. THE CURRENT UNDERSTANDING OF IMMUNE DYSFUNCTION IN MPNS AND ANALOGOUS MYMS OFFERS A COMPELLING RATIONALE TO STUDY PD-1/PD-L1 INHIBITION IN PATIENTS AS A NOVEL TREATMENT OPTION. 2017 2 4837 28 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 3 1260 33 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 2446 41 EPIGENETIC STRATEGIES SYNERGIZE WITH PD-L1/PD-1 TARGETED CANCER IMMUNOTHERAPIES TO ENHANCE ANTITUMOR RESPONSES. IMMUNOTHERAPY STRATEGIES TARGETING THE PROGRAMMED CELL DEATH LIGAND 1 (PD-L1)/PROGRAMMED CELL DEATH 1 (PD-1) PATHWAY IN CLINICAL TREATMENTS HAVE ACHIEVED REMARKABLE SUCCESS IN TREATING MULTIPLE TYPES OF CANCER. HOWEVER, OWING TO THE HETEROGENEITY OF TUMORS AND INDIVIDUAL IMMUNE SYSTEMS, PD-L1/PD-1 BLOCKADE STILL SHOWS SLOW RESPONSE RATES IN CONTROLLING MALIGNANCIES IN MANY PATIENTS. ACCUMULATING EVIDENCE HAS SHOWN THAT AN EFFECTIVE RESPONSE TO ANTI-PD-L1/ANTI-PD-1 THERAPY REQUIRES ESTABLISHING AN INTEGRATED IMMUNE CYCLE. DAMAGE IN ANY STEP OF THE IMMUNE CYCLE IS ONE OF THE MOST IMPORTANT CAUSES OF IMMUNOTHERAPY FAILURE. IMPAIRMENTS IN THE IMMUNE CYCLE CAN BE RESTORED BY EPIGENETIC MODIFICATION, INCLUDING REPROGRAMMING THE ENVIRONMENT OF TUMOR-ASSOCIATED IMMUNITY, ELICITING AN IMMUNE RESPONSE BY INCREASING THE PRESENTATION OF TUMOR ANTIGENS, AND BY REGULATING T CELL TRAFFICKING AND REACTIVATION. THUS, A RATIONAL COMBINATION OF PD-L1/PD-1 BLOCKADE AND EPIGENETIC AGENTS MAY OFFER GREAT POTENTIAL TO RETRAIN THE IMMUNE SYSTEM AND TO IMPROVE CLINICAL OUTCOMES OF CHECKPOINT BLOCKADE THERAPY. 2020 5 102 24 A REGULATORY ROLE FOR CHD2 IN MYELOPOIESIS. THE TRANSCRIPTIONAL PROGRAM THAT DICTATES HAEMATOPOIETIC CELL FATE AND DIFFERENTIATION REQUIRES AN EPIGENETIC REGULATORY AND MEMORY FUNCTION, PROVIDED BY A NETWORK OF EPIGENETIC FACTORS THAT REGULATE DNA METHYLATION, POST-TRANSLATIONAL HISTONE MODIFICATIONS AND CHROMATIN STRUCTURE. DISTURBED EPIGENETIC REGULATION CAUSES PERTURBATIONS IN THE BLOOD CELL DIFFERENTIATION PROGRAM THAT RESULTS IN VARIOUS TYPES OF HAEMATOPOIETIC DISORDERS. THUS, ACCURATE EPIGENETIC REGULATION IS ESSENTIAL FOR FUNCTIONAL HAEMATOPOIESIS. IN THIS STUDY, WE USED A CRISPR-CAS9 SCREENING APPROACH TO IDENTIFY NEW EPIGENETIC REGULATORS IN MYELOID DIFFERENTIATION. WE DESIGNED A CHROMATIN-UMI CRISPR GUIDE LIBRARY TARGETING 1092 EPIGENETIC REGULATORS. PHORBOL 12-MYRISTATE 13-ACETATE (PMA) TREATMENT OF THE CHRONIC MYELOID LEUKAEMIA CELL LINE K-562 WAS USED AS A MEGAKARYOCYTIC MYELOID DIFFERENTIATION MODEL. BOTH PREVIOUSLY DESCRIBED DEVELOPMENTAL EPIGENETIC REGULATORS AND NOVEL FACTORS WERE IDENTIFIED IN OUR SCREEN. IN THIS STUDY, WE VALIDATED AND CHARACTERIZED A ROLE FOR THE CHROMATIN REMODELLER CHD2 IN MYELOID PROLIFERATION AND MEGAKARYOCYTIC DIFFERENTIATION. 2020 6 6584 34 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 7 5433 22 REL/NF-KAPPA B/I KAPPA B SIGNAL TRANSDUCTION IN THE GENERATION AND TREATMENT OF HUMAN CANCER. THE REL/NF-KAPPA B FAMILY IS A GROUP OF STRUCTURALLY-RELATED, TIGHTLY-REGULATED TRANSCRIPTION FACTORS THAT CONTROL THE EXPRESSION OF A MULTITUDE OF GENES INVOLVED IN KEY CELLULAR AND ORGANISMAL PROCESSES. THE REL/NF-KAPPA B SIGNAL TRANSDUCTION PATHWAY IS MISREGULATED IN A VARIETY OF HUMAN CANCERS, ESPECIALLY ONES OF LYMPHOID CELL ORIGIN, DUE EITHER TO GENETIC CHANGES (SUCH AS CHROMOSOMAL REARRANGEMENTS, AMPLIFICATIONS, AND MUTATIONS) OR TO CHRONIC ACTIVATION OF THE PATHWAY BY EPIGENETIC MECHANISMS. CONSTITUTIVE ACTIVATION OF THE REL/NF-KAPPA B PATHWAY CAN CONTRIBUTE TO THE ONCOGENIC STATE IN SEVERAL WAYS, FOR EXAMPLE, BY DRIVING PROLIFERATION, BY ENHANCING CELL SURVIVAL, OR BY PROMOTING ANGIOGENESIS OR METASTASIS. IN MANY CASES, INHIBITION OF REL/NF-KAPPA B ACTIVITY REVERSES ALL OR PART OF THE MALIGNANT STATE. THUS, THE REL/NF-KAPPA B PATHWAY HAS RECEIVED MUCH ATTENTION AS A FOCAL POINT FOR CLINICAL INTERVENTION. 2002 8 5455 31 RESCUE OF A PRIMARY MYELOFIBROSIS MODEL BY RETINOID-ANTAGONIST THERAPY. MOLECULAR TARGETING OF THE TWO RECEPTOR INTERACTION DOMAINS OF THE EPIGENETIC REPRESSOR SILENCING MEDIATOR OF RETINOID AND THYROID HORMONE RECEPTORS (SMRT(MRID)) PRODUCED A TRANSPLANTABLE SKELETAL SYNDROME THAT REDUCED RADIAL BONE GROWTH, INCREASED NUMBERS OF BONE-RESORBING PERIOSTEAL OSTEOCLASTS, AND INCREASED BONE FRACTURE RISK. FURTHERMORE, SMRT(MRID) MICE DEVELOP SPONTANEOUS PRIMARY MYELOFIBROSIS, A CHRONIC, USUALLY IDIOPATHIC DISORDER CHARACTERIZED BY PROGRESSIVE BONE MARROW FIBROSIS. FREQUENTLY LINKED TO POLYCYTHEMIA VERA AND CHRONIC MYELOID LEUKEMIA, MYELOFIBROSIS DISPLAYS HIGH PATIENT MORBIDITY AND MORTALITY, AND CURRENT TREATMENT IS MOSTLY PALLIATIVE. TO DECIPHER THE ETIOLOGY OF THIS DISEASE, WE IDENTIFIED THE THROMBOPOIETIN (TPO) GENE AS A TARGET OF THE SMRT-RETINOIC ACID RECEPTOR SIGNALING PATHWAY IN BONE MARROW STROMAL CELLS. CHRONIC INDUCTION OF TPO IN SMRT(MRID) MICE RESULTS IN UP-REGULATION OF TGF-BETA AND PDGF IN MEGAKARYOCYTES, UNCONTROLLED PROLIFERATION OF BONE MARROW RETICULAR CELLS, AND FIBROSIS OF THE MARROW COMPARTMENT. OF THERAPEUTIC RELEVANCE, WE SHOW THAT THIS SYNDROME CAN BE RESCUED BY RETINOID ANTAGONISTS, DEMONSTRATING THAT THE PHYSICAL INTERFACE BETWEEN SMRT AND RETINOIC ACID RECEPTOR CAN BE A POTENTIAL THERAPEUTIC TARGET TO BLOCK PRIMARY MYELOFIBROSIS DISEASE PROGRESSION. 2013 9 5608 33 RUNX1-EVI1 DISRUPTS LINEAGE DETERMINATION AND THE CELL CYCLE BY INTERFERING WITH RUNX1 AND EVI1 DRIVEN GENE REGULATORY NETWORKS. HEMATOLOGICAL MALIGNANCIES ARE CHARACTERISED BY A BLOCK IN DIFFERENTIATION, WHICH IN MANY CASES IS CAUSED BY RECURRENT MUTATIONS AFFECTING THE ACTIVITY OF HEMATOPOIETIC TRANSCRIPTION FACTORS. RUNX1-EVI1 IS A FUSION PROTEIN FORMED BY THE T(3;21) TRANSLOCATION LINKING TWO TRANSCRIPTION FACTORS REQUIRED FOR NORMAL HEMATOPOIESIS. RUNX1-EVI1 EXPRESSION IS FOUND IN MYELODYSPLASTIC SYNDROME, SECONDARY ACUTE MYELOID LEUKEMIA, AND BLAST CRISIS OF CHRONIC MYELOID LEUKEMIA; WITH CLINICAL OUTCOMES BEING WORSE THAN IN PATIENTS WITH RUNX1-ETO, RUNX1 OR EVI1 MUTATIONS ALONE. RUNX1-EVI1 IS USUALLY FOUND AS A SECONDARY MUTATION, THEREFORE THE MOLECULAR MECHANISMS UNDERLYING HOW RUNX1-EVI1 ALONE CONTRIBUTES TO POOR PROGNOSIS ARE UNKNOWN. TO ADDRESS THIS QUESTION, WE INDUCED EXPRESSION OF RUNX1-EVI1 IN HEMATOPOIETIC CELLS DERIVED FROM AN EMBRYONIC STEM CELL DIFFERENTIATION MODEL. INDUCTION RESULTED IN DISRUPTION OF THE RUNX1-DEPENDENT ENDOTHELIAL-HEMATOPOIETIC TRANSITION, BLOCKED THE CELL CYCLE AND UNDERMINED CELL FATE DECISIONS IN MULTIPOTENT HEMATOPOIETIC PROGENITOR CELLS. INTEGRATIVE ANALYSES OF GENE EXPRESSION WITH CHROMATIN AND TRANSCRIPTION FACTOR BINDING DATA DEMONSTRATED THAT RUNX1-EVI1 BINDING CAUSED THE RE-DISTRIBUTION OF ENDOGENOUS RUNX1 WITHIN THE GENOME AND INTERFERED WITH BOTH RUNX1 AND EVI1 REGULATED GENE EXPRESSION PROGRAMS. IN SUMMARY, RUNX1-EVI1 EXPRESSION ALONE LEADS TO EXTENSIVE EPIGENETIC REPROGRAMMING WHICH IS INCOMPATIBLE WITH HEALTHY BLOOD PRODUCTION. 2021 10 409 33 ANALYSIS OF GENES ENCODING EPIGENETIC REGULATORS IN MYELOPROLIFERATIVE NEOPLASMS: COEXISTENCE OF A NOVEL SETBP1 MUTATION IN A PATIENT WITH A P.V617F JAK2 POSITIVE MYELOFIBROSIS. IN RECENT YEARS IT HAS BEEN SHOWN THAT THE CAUSES OF CHRONIC MYELOPROLIFERATIVE NEOPLASMS (MPNS) ARE MORE COMPLEX THAN A SIMPLE SIGNALING ABERRATION AND MANY OTHER MUTATED GENES AFFECTING DIFFERENT CELL PROCESSES HAVE BEEN DESCRIBED. FOR INSTANCE, MUTATIONS IN GENES ENCODING EPIGENETIC REGULATORS ARE MORE FREQUENT THAN EXPECTED. ONE OF THE LATEST GENES DESCRIBED AS MUTATED IS SET BINDING PROTEIN 1 (SETBP1). IN SILICO TOOLS HAVE REVEALED THAT THERE ARE SEVERAL HUMAN SETBP1 PARALOGOUS TO NUCLEAR RECEPTOR BINDING SET DOMAIN PROTEIN 1 (NSD1), NSD2 AND NSD3, FOR EXAMPLE, WHICH ARE ALSO INVOLVED IN THE DEVELOPMENT OF OTHER HEMATOLOGICAL MALIGNANCIES. THEREFORE, THE PRESENT STUDY ANALYZED THE MUTATIONAL STATUS OF NSD1, NSD2, NSD3 AND SETBP1 IN BCR-ABL1 NEGATIVE MPNS WITH OR WITHOUT JANUS KINASE 2 (JAK2) P.V617F MUTATION. THE PRESENT STUDY REVEALED THAT THE NSD GENES ARE NOT FREQUENTLY MUTATED IN MPNS. HOWEVER, A NOVEL SETBP1 MUTATION WAS IDENTIFIED IN A PATIENT WITH P.V617F JAK2 POSITIVE PRIMARY MYELOFIBROSIS. THESE RESULTS PROVIDE FURTHER INSIGHT INTO THE GENETIC COMPLEXITY OF MPNS. 2019 11 5688 28 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 12 4549 32 MUTATION ANALYSIS OF THERAPY-RELATED MYELOID NEOPLASMS. WE ANALYZED THE GENETIC MUTATION STATUS OF 13 PATIENTS WITH THERAPY-RELATED MYELOID NEOPLASMS (T-MN). CONSISTENT WITH PREVIOUS REPORTS, T-MN CELLS PREFERENTIALLY ACQUIRED MUTATIONS IN TP53 AND EPIGENETIC MODIFYING GENES, INSTEAD OF MUTATIONS IN TYROSINE KINASE AND SPLICEOSOME GENES. FURTHERMORE, WE COMPARED THE MUTATION STATUS OF THREE T-MN CELLS WITH EACH OF THE INITIAL LYMPHOID MALIGNANT CELLS, AND IDENTIFIED COMMON MUTATIONS AMONG T-MN AND THE INITIAL MALIGNANT CELLS IN TWO PATIENTS. IN A PATIENT WHO DEVELOPED CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) AFTER FOLLICULAR LYMPHOMA (FL), TET2 MUTATION WAS IDENTIFIED IN BOTH CMML AND FL CELLS. NOTABLY, THE TET2 MUTATION WAS ALSO IDENTIFIED IN PERIPHERAL BLOOD CELLS IN THE DISEASE-FREE PERIOD WITH THE SAME ALLELIC FREQUENCY AS CMML AND FL CELLS, BUT NOT IN A GERM-LINE CONTROL, INDICATING THAT THE TET2 MUTATION OCCURRED SOMATICALLY IN THE INITIATING CLONE FOR BOTH MALIGNANT CELLS. ON THE OTHER HAND, A GERM-LINE MYB MUTATION WAS IDENTIFIED IN A PATIENT WHO DEVELOPED MYELODYSPLASTIC SYNDROMES (MDS) AFTER FL. THESE RESULTS SUGGEST THAT GERM-LINE DEPOSITION AND CLONAL HEMATOPOIESIS ARE CLOSELY ASSOCIATED WITH T-MN SUSCEPTIBILITY; HOWEVER, FURTHER ANALYSIS IS NECESSARY TO CLARIFY THE MECHANISM REQUIRED TO PROVIDE THE INITIATING CLONE WITH LINEAGE COMMITMENT AND CLONAL EXPANSION. 2018 13 4759 39 NOVEL TREATMENTS FOR MYELOFIBROSIS: BEYOND JAK INHIBITORS. MYELOFIBROSIS IS A CHRONIC HEMATOLOGIC MALIGNANCY CHARACTERIZED BY CONSTITUTIONAL SYMPTOMS, BONE MARROW FIBROSIS, EXTRAMEDULLARY HEMATOPOIESIS RESULTING IN SPLENOMEGALY AND A PROPENSITY TOWARD LEUKEMIC PROGRESSION. GIVEN THE CENTRAL ROLE OF THE JAK-STAT PATHWAY IN THE PATHOBIOLOGY OF MYELOFIBROSIS, JAK INHIBITORS ARE THE MAINSTAY OF CURRENT PHARMACOLOGIC MANAGEMENT. ALTHOUGH THESE THERAPIES HAVE PRODUCED MEANINGFUL IMPROVEMENTS IN SPLENOMEGALY AND SYMPTOM BURDEN, JAK INHIBITORS DO NOT SIGNIFICANTLY IMPACT DISEASE PROGRESSION. IN ADDITION, MANY PATIENTS ARE INELIGIBLE BECAUSE OF DISEASE-RELATED CYTOPENIAS, WHICH ARE EXACERBATED BY JAK INHIBITORS. THEREFORE, THERE IS A CONTINUED EFFORT TO IDENTIFY TARGETS OUTSIDE THE JAK-STAT PATHWAY. IN THIS REVIEW, WE DISCUSS NOVEL THERAPIES IN DEVELOPMENT FOR MYELOFIBROSIS. WE FOCUS ON THE PRECLINICAL RATIONALE, EFFICACY AND SAFETY DATA FOR NON-JAK INHIBITOR THERAPIES THAT HAVE PUBLISHED OR PRESENTED CLINICAL DATA. SPECIFICALLY, WE DISCUSS AGENTS THAT TARGET EPIGENETIC MODIFICATION (PELABRESIB, BOMEDEMSTAT), APOPTOSIS (NAVITOCLAX, NAVTEMDALIN), SIGNALING PATHWAYS (PARSACLISIB), BONE MARROW FIBROSIS (AVID200, PRM-151), IN ADDITION TO OTHER TARGETS INCLUDING TELOMERASE (IMETELSTAT), SELECTIVE INHIBITOR OF NUCLEAR TRANSPORT (SELINEXOR), CD123 (TAGRAXOFUSP) AND ERYTHROID MATURATION (LUSPATERCEPT). WE END BY PROVIDING COMMENTARY ON THE ONGOING AND FUTURE THERAPEUTIC DEVELOPMENT IN MYELOFIBROSIS. 2022 14 5101 35 POLYCOMB FACTOR PHF19 CONTROLS CELL GROWTH AND DIFFERENTIATION TOWARD ERYTHROID PATHWAY IN CHRONIC MYELOID LEUKEMIA CELLS. POLYCOMB GROUP (PCG) OF PROTEINS ARE A GROUP OF HIGHLY CONSERVED EPIGENETIC REGULATORS INVOLVED IN MANY BIOLOGICAL FUNCTIONS, SUCH AS EMBRYONIC DEVELOPMENT, CELL PROLIFERATION, AND ADULT STEM CELL DETERMINATION. PHD FINGER PROTEIN 19 (PHF19) IS AN ASSOCIATED FACTOR OF POLYCOMB REPRESSOR COMPLEX 2 (PRC2), OFTEN UPREGULATED IN HUMAN CANCERS. IN PARTICULAR, MYELOID LEUKEMIA CELL LINES SHOW INCREASED LEVELS OF PHF19, YET LITTLE IS KNOWN ABOUT ITS FUNCTION. HERE, WE HAVE CHARACTERIZED THE ROLE OF PHF19 IN MYELOID LEUKEMIA CELLS. WE DEMONSTRATED THAT PHF19 DEPLETION DECREASES CELL PROLIFERATION AND PROMOTES CHRONIC MYELOID LEUKEMIA (CML) DIFFERENTIATION. MECHANISTICALLY, WE HAVE SHOWN HOW PHF19 REGULATES THE PROLIFERATION OF CML THROUGH A DIRECT REGULATION OF THE CELL CYCLE INHIBITOR P21. FURTHERMORE, WE OBSERVED THAT MTF2, A PHF19 HOMOLOG, PARTIALLY COMPENSATES FOR PHF19 DEPLETION IN A SUBSET OF TARGET GENES, INSTRUCTING SPECIFIC ERYTHROID DIFFERENTIATION. TAKEN TOGETHER, OUR RESULTS SHOW THAT PHF19 IS A KEY TRANSCRIPTIONAL REGULATOR FOR CELL FATE DETERMINATION AND COULD BE A POTENTIAL THERAPEUTIC TARGET FOR MYELOID LEUKEMIA TREATMENT. 2021 15 5899 37 T-CELL DYSFUNCTION IN CHRONIC LYMPHOCYTIC LEUKEMIA FROM AN EPIGENETIC PERSPECTIVE. CELLULAR IMMUNOTHERAPEUTIC APPROACHES SUCH AS CHIMERIC ANTIGEN RECEPTOR (CAR) T-CELL THERAPY IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) THUS FAR HAVE NOT MET THE HIGH EXPECTATIONS. THEREFORE IT IS ESSENTIAL TO BETTER UNDERSTAND THE MOLECULAR MECHANISMS OF CLLINDUCED T-CELL DYSFUNCTION. EVEN THOUGH A SIGNIFICANT NUMBER OF STUDIES ARE AVAILABLE ON T-CELL FUNCTION AND DYSFUNCTION IN CLL PATIENTS, NONE EXAMINE DYSFUNCTION AT THE EPIGENOMIC LEVEL. IN NON-MALIGNANT T-CELL RESEARCH, EPIGENOMICS IS WIDELY EMPLOYED TO DEFINE THE DIFFERENTIATION PATHWAY INTO T-CELL EXHAUSTION. ADDITIONALLY, METABOLIC RESTRICTIONS IN THE TUMOR MICROENVIRONMENT THAT CAUSE T-CELL DYSFUNCTION ARE OFTEN MEDIATED BY EPIGENETIC CHANGES. WITH THIS REVIEW PAPER WE ARGUE THAT UNDERSTANDING THE EPIGENETIC (DYS)REGULATION IN T CELLS OF CLL PATIENTS SHOULD BE LEVELED TO THE KNOWLEDGE WE CURRENTLY HAVE OF THE NEOPLASTIC B CELLS THEMSELVES. THIS WILL PERMIT A COMPLETE UNDERSTANDING OF HOW THESE IMMUNE CELL INTERACTIONS REGULATE T- AND B-CELL FUNCTION. HERE WE RELATE THE CELLULAR AND PHENOTYPIC CHARACTERISTICS OF CLL-INDUCED T-CELL DYSFUNCTION TO EPIGENETIC STUDIES OF T-CELL REGULATION EMERGING FROM CHRONIC VIRAL INFECTION AND TUMOR MODELS. THIS PAPER PROPOSES A FRAMEWORK FOR FUTURE STUDIES INTO THE EPIGENETIC REGULATION OF CLL-INDUCED TCELL DYSFUNCTION, KNOWLEDGE THAT WILL HELP TO GUIDE IMPROVEMENTS IN THE UTILITY OF AUTOLOGOUS T-CELL BASED THERAPIES IN CLL. 2021 16 4545 28 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 1070 34 CLONAL ARCHITECTURE OF CHRONIC MYELOMONOCYTIC LEUKEMIAS. GENOMIC STUDIES IN CHRONIC MYELOID MALIGNANCIES, INCLUDING MYELOPROLIFERATIVE NEOPLASMS (MPN), MYELODYSPLASTIC SYNDROMES (MDS), AND MPN/MDS, HAVE IDENTIFIED COMMON MUTATIONS IN GENES ENCODING SIGNALING, EPIGENETIC, TRANSCRIPTION, AND SPLICING FACTORS. IN THE PRESENT STUDY, WE INTERROGATED THE CLONAL ARCHITECTURE BY MUTATION-SPECIFIC DISCRIMINATION ANALYSIS OF SINGLE-CELL-DERIVED COLONIES IN 28 PATIENTS WITH CHRONIC MYELOMONOCYTIC LEUKEMIAS (CMML), THE MOST FREQUENT MPN/MDS. THIS ANALYSIS REVEALS A LINEAR ACQUISITION OF THE STUDIED MUTATIONS WITH LIMITED BRANCHING THROUGH LOSS OF HETEROZYGOSITY. SERIAL ANALYSIS OF UNTREATED AND TREATED SAMPLES DEMONSTRATES A DYNAMIC ARCHITECTURE ON WHICH MOST CURRENT THERAPEUTIC APPROACHES HAVE LIMITED EFFECTS. THE MAIN DISEASE CHARACTERISTICS ARE EARLY CLONAL DOMINANCE, ARISING AT THE CD34(+)/CD38(-) STAGE OF HEMATOPOIESIS, AND GRANULOMONOCYTIC DIFFERENTIATION SKEWING OF MULTIPOTENT AND COMMON MYELOID PROGENITORS. COMPARISON OF CLONAL EXPANSIONS OF TET2 MUTATIONS IN MDS, MPN, AND CMML, TOGETHER WITH FUNCTIONAL INVALIDATION OF TET2 IN SORTED PROGENITORS, SUGGESTS A CAUSATIVE LINK BETWEEN EARLY CLONAL DOMINANCE AND SKEWED GRANULOMONOCYTIC DIFFERENTIATION. ALTOGETHER, EARLY CLONAL DOMINANCE MAY DISTINGUISH CMML FROM OTHER CHRONIC MYELOID NEOPLASMS WITH SIMILAR GENE MUTATIONS. 2013 18 4388 47 MLL2/KMT2D AND MLL3/KMT2C EXPRESSION CORRELATES WITH DISEASE PROGRESSION AND RESPONSE TO IMATINIB MESYLATE IN CHRONIC MYELOID LEUKEMIA. BACKGROUND: CHRONIC MYELOID LEUKEMIA (CML) IS A CLONAL MYELOPROLIFERATIVE NEOPLASM WHOSE PATHOGENESIS IS LINKED TO THE PHILADELPHIA CHROMOSOME PRESENCE THAT GENERATES THE BCR-ABL1 FUSION ONCOGENE. TYROSINE KINASE INHIBITORS (TKI) SUCH AS IMATINIB MESYLATE (IM) DRAMATICALLY IMPROVED THE TREATMENT EFFICIENCY AND SURVIVAL OF CML PATIENTS BY TARGETING BCR-ABL TYROSINE KINASE. THE DISEASE SHOWS THREE DISTINCT CLINICAL-LABORATORY STAGES: CHRONIC PHASE, ACCELERATED PHASE AND BLAST CRISIS. ALTHOUGH PATIENTS IN THE CHRONIC PHASE RESPOND WELL TO TREATMENT, PATIENTS IN THE ACCELERATED PHASE OR BLAST CRISIS USUALLY SHOW THERAPY RESISTANCE AND CML RELAPSE. IT IS CRUCIAL, THEREFORE, TO IDENTIFY BIOMARKERS TO PREDICT CML GENETIC EVOLUTION AND RESISTANCE TO TKI THERAPY, CONSIDERING NOT ONLY THE EFFECTS OF GENETIC ABERRATIONS BUT ALSO THE ROLE OF EPIGENETIC ALTERATIONS DURING THE DISEASE. ALTHOUGH DYSREGULATIONS IN EPIGENETIC MODULATORS SUCH AS HISTONE METHYLTRASNFERASES HAVE ALREADY BEEN DESCRIBED FOR SOME HEMATOLOGIC MALIGNANCIES, TO DATE VERY LIMITED DATA IS AVAILABLE FOR CML, ESPECIALLY WHEN CONSIDERING THE LYSINE METHYLTRANSFERASE MLL2/KMT2D AND MLL3/KMT2C. METHODS: HERE WE INVESTIGATED THE EXPRESSION PROFILE OF BOTH GENES IN CML PATIENTS IN DIFFERENT STAGES OF THE DISEASE, IN PATIENTS SHOWING DIFFERENT RESPONSES TO THERAPY WITH IM AND IN NON-NEOPLASTIC CONTROL SAMPLES. IMATINIB SENSITIVE AND RESISTANT CML CELL LINES WERE ALSO USED TO INVESTIGATE WHETHER TREATMENT WITH OTHER TYROSINE KINASE INHIBITORS INTERFERED IN THEIR EXPRESSION. RESULTS: IN PATIENTS, BOTH METHYLTRANSFERASES WERE EITHER UPREGULATED OR WITH BASAL EXPRESSION LEVEL DURING THE CHRONIC PHASE COMPARED TO CONTROLS. INTERESTINGLY, MLL3/KMT2C AND SPECIALLY MLL2/KMT2D LEVELS DECREASED DURING DISEASE PROGRESSION CORRELATING WITH DISTINCT CLINICAL STAGES. FURTHERMORE, MLL2/KMT2D WAS DECREASED IN PATIENTS RESISTANT TO IM TREATMENT. A RESCUE IN THE EXPRESSION OF BOTH MLL GENES WAS OBSERVED IN KCL22S, A CML CELL LINE SENSITIVE TO IM, AFTER TREATMENT WITH DASATINIB OR NILOTINIB WHICH WAS ASSOCIATED WITH A HIGHER RATE OF APOPTOSIS, AN ENHANCED EXPRESSION OF P21 (CDKN1A) AND A CONCOMITANT DECREASE IN THE EXPRESSION OF CDK2, CDK4 AND CYCLIN B1 (CCNB1) IN COMPARISON TO UNTREATED KCL22S CONTROL OR IM RESISTANT KCL22R CELL LINE, WHICH SUGGESTS INVOLVEMENT OF P53 REGULATED PATHWAY. CONCLUSION: OUR RESULTS ESTABLISHED A NEW ASSOCIATION BETWEEN MLL2/KMT2D AND MLL3/KMT2C GENES WITH CML AND SUGGEST THAT MLL2/KMT2D IS ASSOCIATED WITH DISEASE EVOLUTION AND MAY BE A POTENTIAL MARKER TO PREDICT THE DEVELOPMENT OF THERAPY RESISTANCE. 2018 19 2462 35 EPIGENETIC THERAPY OF MYELODYSPLASTIC SYNDROMES CONNECTS TO CELLULAR DIFFERENTIATION INDEPENDENTLY OF ENDOGENOUS RETROELEMENT DEREPRESSION. BACKGROUND: MYELODYSPLASTIC SYNDROMES (MDS) AND ACUTE MYELOID LEUKAEMIA (AML) ARE CHARACTERISED BY ABNORMAL EPIGENETIC REPRESSION AND DIFFERENTIATION OF BONE MARROW HAEMATOPOIETIC STEM CELLS (HSCS). DRUGS THAT REVERSE EPIGENETIC REPRESSION, SUCH AS 5-AZACYTIDINE (5-AZA), INDUCE HAEMATOLOGICAL IMPROVEMENT IN HALF OF TREATED PATIENTS. ALTHOUGH THE MECHANISMS UNDERLYING THERAPY SUCCESS ARE NOT YET CLEAR, INDUCTION OF ENDOGENOUS RETROELEMENTS (ERES) HAS BEEN HYPOTHESISED. METHODS: USING RNA SEQUENCING (RNA-SEQ), WE COMPARED THE TRANSCRIPTION OF ERES IN BONE MARROW HSCS FROM A NEW COHORT OF MDS AND CHRONIC MYELOMONOCYTIC LEUKAEMIA (CMML) PATIENTS BEFORE AND AFTER 5-AZA TREATMENT WITH HSCS FROM HEALTHY DONORS AND AML PATIENTS. WE FURTHER EXAMINED ERE TRANSCRIPTION USING THE MOST COMPREHENSIVE ANNOTATION OF ERE-OVERLAPPING TRANSCRIPTS EXPRESSED IN HSCS, GENERATED HERE BY DE NOVO TRANSCRIPT ASSEMBLY AND SUPPORTED BY FULL-LENGTH RNA-SEQ. RESULTS: CONSISTENT WITH PRIOR REPORTS, WE FOUND THAT TREATMENT WITH 5-AZA INCREASED THE REPRESENTATION OF ERE-DERIVED RNA-SEQ READS IN THE TRANSCRIPTOME. HOWEVER, SUCH INCREASES WERE COMPARABLE BETWEEN TREATMENT RESPONSES AND FAILURES. THE EXTENDED VIEW OF HSC TRANSCRIPTIONAL DIVERSITY OFFERED BY DE NOVO TRANSCRIPT ASSEMBLY ARGUED AGAINST 5-AZA-RESPONSIVE ERES AS DETERMINANTS OF THE OUTCOME OF THERAPY. INSTEAD, IT UNCOVERED PRE-TREATMENT EXPRESSION AND ALTERNATIVE SPLICING OF DEVELOPMENTALLY REGULATED GENE TRANSCRIPTS AS PREDICTORS OF THE RESPONSE OF MDS AND CMML PATIENTS TO 5-AZA TREATMENT. CONCLUSIONS: OUR STUDY IDENTIFIES THE DEVELOPMENTALLY REGULATED TRANSCRIPTIONAL SIGNATURES OF PROTEIN-CODING AND NON-CODING GENES, RATHER THAN ERES, AS CORRELATES OF A FAVOURABLE RESPONSE OF MDS AND CMML PATIENTS TO 5-AZA TREATMENT AND OFFERS NOVEL CANDIDATES FOR FURTHER EVALUATION. 2019 20 2469 14 EPIGENETIC TRAJECTORIES OF THE PREMALIGNANT-TO-MALIGNANT TRANSITION OF CHRONIC LYMPHOCYTIC LEUKEMIA. KRETZMER AND COLLEAGUES SHOW THAT THE TRANSITION TO ALTERED METHYLOME OCCURS VERY EARLY IN CHRONIC LYMPHOCYTIC LEUKEMIA, AND ONCE ACQUIRED, IT IS A CLONAL AND EXTREMELY STABLE CHANGE. HOWEVER, THE PRECISE TIME POINT WHEN THE LEUKEMIC CLONE STARTS DEVIATING SIGNIFICANTLY FROM THE NORMAL B-CELL DIFFERENTIATION TRAJECTORY IS STILL ELUSIVE. SEE RELATED ARTICLE BY KRETZMER ET AL., P. 54. 2021