1 202 92 ACTIVATION INDUCED CYTIDINE DEAMINASE: AN OLD FRIEND WITH NEW FACES. ACTIVATION INDUCED CYTIDINE DEAMINASE (AID) PROTEIN IS A MEMBER OF APOBEC FAMILY. AID CONVERTS CYTIDINE TO URACIL, WHICH IS A KEY STEP FOR SOMATIC HYPERMUTATION (SHM) AND CLASS SWITCH RECOMBINATION (CSR). AID ALSO PLAYS CRITICAL ROLES IN B CELL PRECURSOR STAGES, REMOVING POLYREACTIVE B CELLS FROM IMMUNE REPERTOIRE. SINCE THE MAIN FUNCTION OF AID IS INDUCING POINT MUTATIONS, DYSREGULATION CAN LEAD TO INCREASED MUTATION LOAD, TRANSLOCATIONS, DISTURBED GENOMIC INTEGRITY, AND LYMPHOMAGENESIS. AS SUCH, EXPRESSION OF AID AS WELL AS ITS FUNCTION IS CONTROLLED STRICTLY AT VARIOUS MOLECULAR STEPS. OTHER MEMBERS OF THE APOBEC FAMILY ALSO PLAY CRUCIAL ROLES DURING CARCINOGENESIS. CONSIDERING ALL THESE FUNCTIONS, AID REPRESENTS A BRIDGE, LINKING CHRONIC INFLAMMATION TO CARCINOGENESIS AND IMMUNE DEFICIENCIES TO AUTOIMMUNE MANIFESTATIONS. 2022 2 1775 28 EBV IN T-/NK-CELL TUMORIGENESIS. EPSTEIN-BARR VIRUS (EBV), WHICH IS ASSOCIATED WITH B-CELL PROLIFERATIVE DISORDERS, ALSO TRANSFORMS T- OR NATURAL KILLER (NK)-LINEAGE CELLS AND HAS BEEN CONNECTED WITH VARIOUS T- OR NK (T/NK)-CELL MALIGNANCIES, SUCH AS EXTRANODAL NK/T-CELL LYMPHOMA-NASAL TYPE AND AGGRESSIVE NK-CELL LEUKEMIA. CHRONIC ACTIVE EBV (CAEBV) DISEASE , WHICH OCCURS MOST OFTEN IN CHILDREN AND YOUNG ADULTS IN EAST ASIA, IS AN EBV-ASSOCIATED T-/NK-CELL LYMPHOPROLIFERATIVE DISEASE. PATIENTS WITH CAEBV OFTEN PROGRESS TO OVERT LYMPHOMA OR LEUKEMIA OVER A LONG-TERM CLINICAL COURSE. EBV'S TRANSFORMING CAPACITY IN B CELLS IS WELL CHARACTERIZED, BUT THE MOLECULAR PATHOGENESIS OF CLONAL EXPANSION CAUSED BY EBV IN T/NK CELLS HAS NOT YET BEEN CLARIFIED. IN THE PRIMARY INFECTION, EBV INFECTS B CELLS AND EPITHELIAL CELLS AND MAY ALSO INFECT SOME T/NK CELLS. IN SOME INDIVIDUALS, BECAUSE OF POOR PRESENTATION BY SPECIFIC HUMAN LEUKOCYTE ANTIGENS OR THE GENETIC BACKGROUND, EBV-INFECTED T/NK CELLS EVADE HOST IMMUNITY AND SURVIVE. OCCASIONALLY, WITH THE HELP OF VIRAL ONCOGENES, EBV-ASSOCIATED T/NK LYMPHOPROLIFERATIVE DISEASES, SUCH AS CAEBV, MAY DEVELOP. THE SUBSEQUENT ACCUMULATION OF GENETIC MUTATIONS AND/OR EPIGENETIC MODIFICATIONS IN DRIVER GENES, SUCH AS DDX3X AND TP53, MAY LEAD TO OVERT LYMPHOMA AND LEUKEMIA. ACTIVATION-INDUCED CYTIDINE DEAMINASE AND THE APOBEC3 FAMILY, DRIVEN BY EBV INFECTION, MAY INDUCE CHROMOSOMAL RECOMBINATION AND SOMATIC MUTATIONS. 2018 3 208 43 ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID) LINKING IMMUNITY, CHRONIC INFLAMMATION, AND CANCER. ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID) IS CRITICALLY INVOLVED IN CLASS SWITCH RECOMBINATION AND SOMATIC HYPERMUTATION OF IG LOCI RESULTING IN DIVERSIFICATION OF ANTIBODIES REPERTOIRE AND PRODUCTION OF HIGH-AFFINITY ANTIBODIES AND AS SUCH REPRESENTS A PHYSIOLOGICAL TOOL TO INTRODUCE DNA ALTERATIONS. THESE PROCESSES TAKE PLACE WITHIN GERMINAL CENTERS OF SECONDARY LYMPHOID ORGANS. UNDER PHYSIOLOGICAL CONDITIONS, AID IS EXPRESSED PREDOMINANTLY IN ACTIVATED B LYMPHOCYTES. BECAUSE OF THE MUTAGENIC AND RECOMBINOGENIC POTENTIAL OF AID, ITS EXPRESSION AND ACTIVITY IS TIGHTLY REGULATED ON DIFFERENT LEVELS TO MINIMIZE THE RISK OF UNWANTED DNA DAMAGE. HOWEVER, CHRONIC INFLAMMATION AND, PROBABLY, COMBINATION OF OTHER NOT-YET-IDENTIFIED FACTORS ARE ABLE TO CREATE A MICROENVIRONMENT SUFFICIENT FOR TRIGGERING AN ABERRANT AID EXPRESSION IN B CELLS AND, IMPORTANTLY, IN NON-B-CELL BACKGROUND. UNDER THESE CIRCUMSTANCES, AID MAY TARGET ALSO NON-IG GENES, INCLUDING CANCER-RELATED GENES AS ONCOGENES, TUMOR SUPPRESSOR GENES, AND GENOMIC STABILITY GENES, AND MODULATE BOTH GENETIC AND EPIGENETIC INFORMATION. DESPITE ONGOING PROGRESS, THE COMPLETE UNDERSTANDING OF FUNDAMENTAL ASPECTS IS STILL LACKING AS (1) WHAT ARE THE CRUCIAL FACTORS TRIGGERING AN ABERRANT AID EXPRESSION/ACTIVITY INCLUDING THE IMPACT OF TH2-DRIVEN INFLAMMATION AND (2) TO WHAT EXTENT MAY ABERRANT AID IN HUMAN NON-B CELLS LEAD TO ABNORMAL CELL STATE ASSOCIATED WITH AN INCREASED RATE OF GENOMIC ALTERATIONS AS POINT MUTATIONS, SMALL INSERTIONS OR DELETIONS, AND/OR RECURRENT CHROMOSOMAL TRANSLOCATIONS DURING SOLID TUMOR DEVELOPMENT AND PROGRESSION. 2012 4 3685 35 INFLAMMATION-ASSOCIATED CANCER DEVELOPMENT IN DIGESTIVE ORGANS: MECHANISMS AND ROLES FOR GENETIC AND EPIGENETIC MODULATION. CHRONIC INFLAMMATION, REGARDLESS OF INFECTIOUS AGENTS, PLAYS IMPORTANT ROLES IN THE DEVELOPMENT OF VARIOUS CANCERS, PARTICULARLY IN DIGESTIVE ORGANS, INCLUDING HELICOBACTER PYLORI-ASSOCIATED GASTRIC CANCER, HEPATITIS C VIRUS-POSITIVE HEPATOCELLULAR CARCINOMA, AND COLITIS-ASSOCIATED COLON CANCERS. CANCER DEVELOPMENT IS CHARACTERIZED BY STEPWISE ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS OF VARIOUS PROTO-ONCOGENES AND TUMOR-SUPPRESSOR GENES. DURING CHRONIC INFLAMMATION, INFECTIOUS AGENTS SUCH AS H PYLORI AND HEPATITIS C VIRUS AS WELL AS INTRINSIC MEDIATORS OF INFLAMMATORY RESPONSES, INCLUDING PROINFLAMMATORY CYTOKINES AND REACTIVE OXYGEN AND NITROGEN SPECIES, CAN INDUCE GENETIC AND EPIGENETIC CHANGES, INCLUDING POINT MUTATIONS, DELETIONS, DUPLICATIONS, RECOMBINATIONS, AND METHYLATION OF VARIOUS TUMOR-RELATED GENES THROUGH VARIOUS MECHANISMS. FURTHERMORE, INFLAMMATION ALSO MODULATES THE EXPRESSIONS OF MICRORNAS THAT INFLUENCE THE PRODUCTION OF SEVERAL TUMOR-RELATED MESSENGER RNAS OR PROTEINS. THESE MOLECULAR EVENTS INDUCED BY CHRONIC INFLAMMATION WORK IN CONCERT TO ALTER IMPORTANT PATHWAYS INVOLVED IN NORMAL CELLULAR FUNCTION, AND HENCE ACCELERATE INFLAMMATION-ASSOCIATED CANCER DEVELOPMENT. AMONG THESE, RECENT STUDIES HIGHLIGHTED AN IMPORTANT ROLE OF ACTIVATION-INDUCED CYTIDINE DEAMINASE, A NUCLEOTIDE-EDITING ENZYME ESSENTIAL FOR SOMATIC HYPERMUTATION AND CLASS-SWITCH RECOMBINATION OF THE IMMUNOGLOBULIN GENE, AS A GENOMIC MODULATOR IN INFLAMMATION-ASSOCIATED CANCER DEVELOPMENT. 2012 5 209 30 ACTIVATION-INDUCED CYTIDINE DEAMINASE: IN SICKNESS AND IN HEALTH. ACTIVATION INDUCED CYTIDINE DEAMINASE (AID) IS AN ESSENTIAL ENZYME OF THE ADAPTIVE IMMUNE SYSTEM. ITS CANONICAL ACTIVITY IS RESTRICTED TO B LYMPHOCYTES, PLAYING AN ESSENTIAL ROLE IN THE DIVERSIFICATION OF ANTIBODIES BY ENHANCING SPECIFICITY AND CHANGING AFFINITY. THIS IS POSSIBLE THROUGH ITS DNA DEAMINASE FUNCTION, LEADING TO MUTATIONS IN DNA. IN THE LAST DECADE, AID HAS BEEN ASSIGNED AN ADDITIONAL FUNCTION: THAT OF A POWERFUL DNA DEMETHYLATOR. ADVERSE CELLULAR CONDITIONS SUCH AS CHRONIC INFLAMMATION CAN LEAD TO ITS DEREGULATION AND OVEREXPRESSION. IT IS AN IMPORTANT DRIVER OF B-CELL LYMPHOMA DUE TO ITS NATURAL ABILITY TO MODIFY DNA THROUGH DEAMINATION, LEADING TO MUTATIONS AND EPIGENETIC CHANGES. HOWEVER, THE DEREGULATION OF AID IS NOT RESTRICTED TO LYMPHOID CELLS. RECENT FINDINGS HAVE PROVIDED NEW INSIGHTS INTO THE ROLE THAT THIS PROTEIN PLAYS IN THE DEVELOPMENT OF NON-LYMPHOID CANCERS, WITH SOME RESEARCH SHEDDING LIGHT ON NOVEL AID-DRIVEN MECHANISMS OF CELLULAR TRANSFORMATION. IN THIS REVIEW, WE PROVIDE AN UPDATED NARRATIVE OF THE NORMAL PHYSIOLOGICAL FUNCTIONS OF AID. ADDITIONALLY, WE REVIEW AND DISCUSS THE RECENT RESEARCH STUDIES THAT HAVE IMPLICATED AID IN CARCINOGENESIS IN VARYING TISSUE TYPES INCLUDING LYMPHOID AND NON-LYMPHOID CANCERS. WE REVIEW THE MECHANISMS, WHEREBY AID PROMOTES CARCINOGENESIS AND HIGHLIGHT IMPORTANT AREAS OF FUTURE RESEARCH. 2020 6 6841 25 [MECHANISMS OF H. PYLORI INFECTION-INDUCED GASTRIC CARCINOGENESIS]. MANY EPIDEMIOLOGICAL STUDIES HAVE DEMONSTRATED A STRONG ASSOCIATION BETWEEN H. PYLORI (HELICOBACTER PYLORI) INFECTION AND HUMAN GASTRIC CANCER DEVELOPMENT. THE PRECISE MECHANISMS ACCOUNTING FOR GASTRIC CANCER DEVELOPMENT INDUCED BY H. PYLORI INFECTION ARE STILL NOT COMPLETELY UNDERSTOOD. HOWEVER, IT SHOULD BE REASONABLE TO ASSUME THAT THERE ARE TWO DISTINCT MOLECULAR PATHWAYS FOR GASTRIC CARCINOGENESIS BY H. PYLORI INFECTION; THE DIRECT ACTION OF THE BACTERIA ITSELF ON GASTRIC EPITHELIAL CELLS, AND THE ACCUMULATION OF GENETIC CHANGES CAUSED BY PROLONGED BACTERIAL INFECTION AND CHRONIC INFLAMMATION. AS A DIRECT ACTION OF H. PYLORI, BACTERIAL PROTEINS SUCH AS CAGA COULD BE DELIVERED INTO GASTRIC EPITHELIAL CELLS VIA THE TYPE IV SECRETION APPARATUS AND MODIFY THE HOST CELL FUNCTIONS RELATED TO CELL PROLIFERATION. IN ADDITION TO THE DIRECT BACTERIAL ACTION, H. PYLORI INFECTION AND THE RESULTANT INFLAMMATORY RESPONSE CAUSE VARIOUS GENETIC AND EPIGENETIC CHANGES IN TUMOR-RELATED GENES OF THE GASTRIC EPITHELIAL CELLS. NOTABLY, EXPRESSION OF AID (ACTIVATION-INDUCED CYTIDINE DEAMINASE), A DNA EDITING ENZYME THAT UNDERGOES SOMATIC HYPERMUTATION ON HUMAN GENES, IS INDUCED IN RESPONSE TO H. PYLORI INFECTION AND PROINFLAMMATORY CYTOKINE STIMULATION IN HUMAN GASTRIC EPITHELIAL CELLS. AS A RESULT, THE ACCUMULATION OF GENETIC ALTERATIONS WOULD PERSIST UNTIL THE CLINICAL STAGE OF ATROPHIC GASTRITIS AND EVENTUALLY TRIGGER THE MALIGNANT TRANSFORMATION OF GASTRIC CELLS. 2010 7 5266 21 PROMOTED INTERACTION OF C/EBPALPHA WITH DEMETHYLATED CXCR3 GENE PROMOTER CONTRIBUTES TO NEUROPATHIC PAIN IN MICE. DNA METHYLATION HAS BEEN IMPLICATED IN THE PATHOGENESIS OF CHRONIC PAIN. HOWEVER, THE SPECIFIC GENES REGULATED BY DNA METHYLATION UNDER NEUROPATHIC PAIN CONDITION REMAIN LARGELY UNKNOWN. HERE WE INVESTIGATED HOW CHEMOKINE RECEPTOR CXCR3 IS REGULATED BY DNA METHYLATION AND HOW IT CONTRIBUTES TO NEUROPATHIC PAIN INDUCED BY SPINAL NERVE LIGATION (SNL) IN MICE. SNL INCREASED CXCR3 MRNA AND PROTEIN EXPRESSION IN THE NEURONS OF THE SPINAL CORD. MEANWHILE, THE CPG (5'-CYTOSINE-PHOSPHATE-GUANINE-3') ISLAND IN THE CXCR3 GENE PROMOTER REGION WAS DEMETHYLATED, AND THE EXPRESSION OF DNA METHYLTRANSFERASE 3B (DNMT3B) WAS DECREASED. SNL ALSO INCREASED THE BINDING OF CCAAT (CYTIDINE-CYTIDINE-ADENOSINE-ADENOSINE-THYMIDINE)/ENHANCER BINDING PROTEIN ALPHA (C/EBPALPHA) WITH CXCR3 PROMOTER AND DECREASED THE BINDING OF DNMT3B WITH CXCR3 PROMOTER IN THE SPINAL CORD. C/EBPALPHA EXPRESSION WAS INCREASED IN SPINAL NEURONS AFTER SNL, AND INHIBITION OF C/EBPALPHA BY INTRATHECAL SMALL INTERFERING RNA ATTENUATED SNL-INDUCED PAIN HYPERSENSITIVITY AND REDUCED CXCR3 EXPRESSION. FURTHERMORE, SNL-INDUCED MECHANICAL ALLODYNIA AND HEAT HYPERALGESIA WERE MARKEDLY REDUCED IN CXCR3(-/-) MICE. SPINAL INHIBITION OF CXCR3 BY SHRNA OR CXCR3 ANTAGONIST ALSO ATTENUATED ESTABLISHED NEUROPATHIC PAIN. MOREOVER, CXCL10, THE LIGAND OF CXCR3, WAS INCREASED IN SPINAL NEURONS AND ASTROCYTES AFTER SNL. SUPERFUSING SPINAL CORD SLICES WITH CXCL10 ENHANCED SPONTANEOUS EPSCS AND POTENTIATED NMDA-INDUCED AND AMPA-INDUCED CURRENTS OF LAMINA II NEURONS. FINALLY, INTRATHECAL INJECTION OF CXCL10 INDUCED CXCR3-DEPENDENT PAIN HYPERSENSITIVITY IN NAIVE MICE. COLLECTIVELY, OUR RESULTS DEMONSTRATED THAT CXCR3, INCREASED BY DNA DEMETHYLATION AND THE ENHANCED INTERACTION WITH C/EBPALPHA, CAN BE ACTIVATED BY CXCL10 TO FACILITATE EXCITATORY SYNAPTIC TRANSMISSION AND CONTRIBUTE TO THE MAINTENANCE OF NEUROPATHIC PAIN. SIGNIFICANCE STATEMENT: PERIPHERAL NERVE INJURY INDUCES CHANGES OF GENE EXPRESSION IN THE SPINAL CORD THAT MAY CONTRIBUTE TO THE PATHOGENESIS OF NEUROPATHIC PAIN. CXCR3 IS A CHEMOKINE RECEPTOR. WHETHER IT IS INVOLVED IN NEUROPATHIC PAIN AND HOW IT IS REGULATED AFTER NERVE INJURY REMAIN LARGELY UNKNOWN. OUR STUDY DEMONSTRATES THAT SPINAL NERVE LIGATION DOWNREGULATES THE EXPRESSION OF DNMT3B, WHICH MAY CAUSE DEMETHYLATION OF CXCR3 GENE PROMOTER AND FACILITATE THE BINDING OF CCAAT/ENHANCER BINDING PROTEIN ALPHA WITH CXCR3 PROMOTER AND FURTHER INCREASE CXCR3 EXPRESSION IN SPINAL NEURONS. THE UPREGULATED CXCR3 MAY CONTRIBUTE TO NEUROPATHIC PAIN BY FACILITATING CENTRAL SENSITIZATION. OUR STUDY REVEALS AN EPIGENETIC MECHANISM UNDERLYING CXCR3 EXPRESSION AND ALSO SUGGESTS THAT TARGETING THE EXPRESSION OR ACTIVATION OF CXCR3 SIGNALING MAY OFFER NEW THERAPEUTICS FOR NEUROPATHIC PAIN. 2017 8 1700 26 DYNAMIC EXPRESSION OF ZNF382 AND ITS TUMOR-SUPPRESSOR ROLE IN HEPATITIS B VIRUS-RELATED HEPATOCELLULAR CARCINOGENESIS. HEPATITIS B VIRUS (HBV) INFECTION IS THE PRIMARY CAUSE OF HEPATOCELLULAR CARCINOMA (HCC). ZINC-FINGER PROTEIN 382 (ZNF382), WHICH BELONGS TO ZINC-FINGER PROTEIN FAMILY, HAS BEEN DOCUMENTED TO BE DOWNREGULATED IN CERTAIN TYPES OF CANCER. HOWEVER, ITS ROLE IN HCC REMAINS LARGELY UNKNOWN. IN THIS STUDY, WE DEMONSTRATED THAT ZNF382 EXPRESSION WAS SIGNIFICANTLY ELEVATED IN HBV-INFECTED LIVER CIRRHOSIS TISSUES RELATIVE TO HBV-NEGATIVE NORMAL LIVER TISSUES AT PROTEIN LEVELS, BUT NOT AT MRNA LEVELS, AND WAS POSITIVELY CORRELATED WITH THE LEVELS OF HBV DNA AND HEPATITIS B VIRUS X PROTEIN (HBX). FURTHER STUDIES REVEALED THAT ZNF382 WAS A TARGET OF MIR-6867, AND HBX PROMOTED THE TRANSLATION OF ZNF382 DURING HBV CHRONIC INFECTION THROUGH ERK-MEDIATED MIR-6867 INHIBITION. IN ADDITION, OUR DATA SHOWED THAT ZNF382 WAS FREQUENTLY DOWNREGULATED BY PROMOTER METHYLATION IN HBV-RELATED HCCS RELATIVE TO HBV-INFECTED LIVER CIRRHOSIS TISSUES, AND DECREASED EXPRESSION OF ZNF382 WAS STRONGLY CORRELATED WITH POOR SURVIVAL IN EARLY-STAGE HCC PATIENTS. FUNCTIONAL STUDIES DEMONSTRATED THAT ZNF382 WAS A POTENT TUMOR SUPPRESSOR IN HCC CELLS THROUGH INHIBITING CELL PROLIFERATION, COLONY FORMATION, MIGRATION, INVASION, AND TUMORIGENIC POTENTIAL IN NUDE MICE, AND INDUCING CELL APOPTOSIS. MECHANISTICALLY, ZNF382 EXERTED ITS TUMOR-SUPPRESSOR FUNCTIONS IN HCC THROUGH TRANSCRIPTIONALLY REPRESSING ITS DOWNSTREAM TARGETS SUCH AS FOS PROTO-ONCOGENE (FOS), JUN PROTO-ONCOGENE (JUN), DISHEVELED SEGMENT POLARITY PROTEIN 2 (DVL2), AND FRIZZLED CLASS RECEPTOR 1 (FZD1), THEREBY IMPAIRING THE ACTIVITIES OF ACTIVATING PROTEIN 1 (AP-1) AND WNT/BETA-CATENIN PATHWAYS AND ACTIVATING P53 SIGNALING. ALTOGETHER, OUR DATA SHOW THAT ZNF382 ACTS AS A TUMOR SUPPRESSOR, AND IS CO-REGULATED BY HBX AND EPIGENETIC MECHANISM IN HBV-RELATED HEPATOCELLULAR CARCINOGENESIS. 2019 9 205 19 ACTIVATION OF HLA-G EXPRESSION BY 5-AZA-2 - DEOXYCYTIDINE IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM LEUKEMIA PATIENTS. HUMAN LEUKOCYTE ANTIGEN - G (HLA-G) IS A NON-CLASSICAL HLA CLASS I ANTIGEN WITH RESTRICTED DISTRIBUTION IN NORMAL TISSUES. ECTOPIC HLA-G EXPRESSION OBSERVED AT SOME PATHOLOGICAL CIRCUMSTANCES AS MALIGNANT TRANSFORMATION MIGHT BE TRIGGERED BY EPIGENETIC MODIFICATIONS SUCH AS DNA DEMETHYLATION. RECENTLY IT WAS DEMONSTRATED THAT DNA METHYLTRANSFERASE INHIBITOR 5-AZA-2 - DEOXYCYTIDINE (ADC) INDUCES/ENHANCES HLA-G TRANSCRIPTION IN MANY LEUKEMIA CELL LINES OF DIFFERENT ORIGIN. HERE WE INVESTIGATED THE EFFECT OF ADC ON HLA-G EXPRESSION IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM PATIENTS WITH ACUTE MYELOID LEUKEMIA (AML) AND CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL). WE DETECTED HLA-G EXPRESSION IN UNTREATED CELLS FROM SOME PATIENTS. NEVERTHELESS TREATMENT WITH 5-AZA-2 - DEOXYCYTIDINE ENHANCED HLA-G TRANSCRIPTION AND CONCOMITANTLY HLA-G PROTEIN SYNTHESIS IN SOME LEUKEMIA CELLS. 2009 10 6004 27 THE AID DILEMMA: INFECTION, OR CANCER? ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID), WHICH IS BOTH ESSENTIAL AND SUFFICIENT FOR FORMING ANTIBODY MEMORY, IS ALSO LINKED TO TUMORIGENESIS. AID IS FOUND IN MANY B LYMPHOMAS, IN MYELOID LEUKEMIA, AND IN PATHOGEN-INDUCED TUMORS SUCH AS ADULT T CELL LEUKEMIA. ALTHOUGH THERE IS NO SOLID EVIDENCE THAT AID CAUSES HUMAN TUMORS, AID-TRANSGENIC AND AID-DEFICIENT MOUSE MODELS INDICATE THAT AID IS BOTH SUFFICIENT AND REQUIRED FOR TUMORIGENESIS. RECENTLY, AID'S ABILITY TO CLEAVE DNA HAS BEEN SHOWN TO DEPEND ON TOPOISOMERASE 1 (TOP1) AND A HISTONE H3K4 EPIGENETIC MARK. WHEN THE LEVEL OF TOP1 PROTEIN IS DECREASED BY AID ACTIVATION, IT INDUCES IRREVERSIBLE CLEAVAGE IN HIGHLY TRANSCRIBED TARGETS. THIS FINDING AND OTHERS LED TO THE IDEA THAT THERE IS AN EVOLUTIONARY LINK BETWEEN MEIOTIC RECOMBINATION AND CLASS SWITCH RECOMBINATION, WHICH SHARE H3K4 TRIMETHYL, TOPOISOMERASE, THE MRN COMPLEX, MISMATCH REPAIR FAMILY PROTEINS, AND EXONUCLEASE 3. AS TOP1 HAS RECENTLY BEEN SHOWN TO BE INVOLVED IN MANY TRANSCRIPTION-ASSOCIATED GENOME INSTABILITIES, IT IS LIKELY THAT AID TOOK ADVANTAGE OF BASIC GENOME INSTABILITY OR DIVERSIFICATION TO EVOLVE ITS MECHANISM FOR IMMUNE DIVERSITY. AID TARGETS ARE THEREFORE NOT HIGHLY SPECIFIC TO IMMUNOGLOBULIN GENES AND ARE RELATIVELY ABUNDANT, ALTHOUGH THEY HAVE STRICT REQUIREMENTS FOR TRANSCRIPTION-INDUCED H3K4 TRIMETHYL MODIFICATION AND REPETITIVE SEQUENCES PRONE TO FORMING NON-B STRUCTURES. INEVITABLY, AID-DEPENDENT CLEAVAGE TAKES PLACE IN NONIMMUNOGLOBULIN TARGETS AND EVENTUALLY CAUSES TUMORS. HOWEVER, BATTLES AGAINST INFECTION ARE WAGED IN THE CONTEXT OF ACUTE EMERGENCIES, WHILE TUMORIGENESIS IS RATHER A CHRONIC, LONG-TERM PROCESS. IN THE INTEREST OF SURVIVAL, VERTEBRATES MUST HAVE EVOLVED AID TO PREVENT INFECTION DESPITE ITS LONG-TERM RISK OF CAUSING TUMORIGENESIS. 2012 11 1176 25 CONTROL OF APOBEC3B INDUCTION AND CCCDNA DECAY BY NF-KAPPAB AND MIR-138-5P. BACKGROUND & AIMS: IMMUNE-MEDIATED INDUCTION OF CYTIDINE DEAMINASE APOBEC3B (A3B) EXPRESSION LEADS TO HBV COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) DECAY. HERE, WE AIMED TO DECIPHER THE SIGNALLING PATHWAY(S) AND REGULATORY MECHANISM(S) INVOLVED IN A3B INDUCTION AND RELATED HBV CONTROL. METHODS: DIFFERENTIATED HEPARG CELLS (DHEPARG) KNOCKED-DOWN FOR NF-KAPPAB SIGNALLING COMPONENTS, TRANSFECTED WITH SIRNA OR MICRO RNAS (MIRNA), AND PRIMARY HUMAN HEPATOCYTES +/- HBV OR HBVDELTAX OR HBV-RFP, WERE TREATED WITH LYMPHOTOXIN BETA RECEPTOR (LTBETAR)-AGONIST (BS1). THE BIOLOGICAL OUTCOMES WERE ANALYSED BY REVERSE TRANSCRIPTASE-QPCR, IMMUNOBLOTTING, LUCIFERASE ACTIVITY, CHROMATIN IMMUNE PRECIPITATION, ELECTROPHORETIC MOBILITY-SHIFT ASSAY, TARGETED-BISULFITE-, MIRNA-, RNA-, GENOME-SEQUENCING, AND MASS-SPECTROMETRY. RESULTS: WE FOUND THAT CANONICAL AND NON-CANONICAL NF-KAPPAB SIGNALLING PATHWAYS ARE MANDATORY FOR A3B INDUCTION AND ANTI-HBV EFFECTS. THE DEGREE OF IMMUNE-MEDIATED A3B PRODUCTION IS INDEPENDENT OF A3B PROMOTER DEMETHYLATION BUT IS CONTROLLED POST-TRANSCRIPTIONALLY BY THE MIRNA 138-5P EXPRESSION (HSA-MIR-138-5P), PROMOTING A3B MRNA DECAY. HSA-MIR-138-5P OVER-EXPRESSION REDUCED A3B LEVELS AND ITS ANTIVIRAL EFFECTS. OF NOTE, ESTABLISHED INFECTION INHIBITED BS1-INDUCED A3B EXPRESSION THROUGH EPIGENETIC MODULATION OF A3B PROMOTER. TWELVE DAYS OF TREATMENT WITH A LTBETAR-SPECIFIC AGONIST BS1 IS SUFFICIENT TO REDUCE THE CCCDNA POOL BY 80% WITHOUT INDUCING SIGNIFICANT DAMAGES TO A SUBSET OF CANCER-RELATED HOST GENES. INTERESTINGLY, THE A3B-MEDIATED EFFECT ON HBV IS INDEPENDENT OF THE TRANSCRIPTIONAL ACTIVITY OF CCCDNA AS WELL AS ON RCDNA SYNTHESIS. CONCLUSIONS: ALTOGETHER, A3B REPRESENTS THE ONLY DESCRIBED ENZYME TO TARGET BOTH TRANSCRIPTIONALLY ACTIVE AND INACTIVE CCCDNA. THUS, INHIBITING HSA-MIR-138-5P EXPRESSION SHOULD BE CONSIDERED IN THE COMBINATORIAL DESIGN OF NEW THERAPIES AGAINST HBV, ESPECIALLY IN THE CONTEXT OF IMMUNE-MEDIATED A3B INDUCTION. LAY SUMMARY: IMMUNE-MEDIATED INDUCTION OF CYTIDINE DEAMINASE APOBEC3B IS TRANSCRIPTIONALLY REGULATED BY NF-KAPPAB SIGNALLING AND POST-TRANSCRIPTIONALLY DOWNREGULATED BY HSA-MIR-138-5P EXPRESSION, LEADING TO CCCDNA DECAY. TIMELY CONTROLLED APOBEC3B-MEDIATED CCCDNA DECAY OCCURS INDEPENDENTLY OF CCCDNA TRANSCRIPTIONAL ACTIVITY AND WITHOUT DAMAGE TO A SUBSET OF CANCER-RELATED GENES. THUS, APOBEC3B-MEDIATED CCCDNA DECAY COULD OFFER AN EFFICIENT THERAPEUTIC ALTERNATIVE TO TARGET HEPATITIS B VIRUS CHRONIC INFECTION. 2021 12 1621 31 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 13 3894 23 LAMIN B1 REGULATES SOMATIC MUTATIONS AND PROGRESSION OF B-CELL MALIGNANCIES. SOMATIC HYPERMUTATION (SHM) IS A PIVOTAL PROCESS IN ADAPTIVE IMMUNITY THAT OCCURS IN THE GERMINAL CENTRE AND ALLOWS B CELLS TO CHANGE THEIR PRIMARY DNA SEQUENCE AND DIVERSIFY THEIR ANTIGEN RECEPTORS. HERE, WE REPORT THAT GENOME BINDING OF LAMIN B1, A COMPONENT OF THE NUCLEAR ENVELOPE INVOLVED IN EPIGENETIC CHROMATIN REGULATION, IS REDUCED DURING B-CELL ACTIVATION AND FORMATION OF LYMPHOID GERMINAL CENTRES. CHROMATIN IMMUNOPRECIPITATION-SEQ ANALYSIS SHOWED THAT KAPPA AND HEAVY VARIABLE IMMUNOGLOBULIN DOMAINS WERE RELEASED FROM THE LAMIN B1 SUPPRESSIVE ENVIRONMENT WHEN SHM WAS INDUCED IN B CELLS. RNA INTERFERENCE-MEDIATED REDUCTION OF LAMIN B1 RESULTED IN SPONTANEOUS SHM AS WELL AS KAPPA-LIGHT CHAIN ABERRANT SURFACE EXPRESSION. FINALLY, LAMIN B1 EXPRESSION LEVEL CORRELATED WITH PROGRESSION-FREE AND OVERALL SURVIVAL IN CHRONIC LYMPHOCYTIC LEUKAEMIA, AND WAS STRONGLY INVOLVED IN THE TRANSFORMATION OF FOLLICULAR LYMPHOMA. IN SUMMARY, HERE WE REPORT THAT LAMIN B1 IS A NEGATIVE EPIGENETIC REGULATOR OF SHM IN NORMAL B-CELLS AND A 'MUTATIONAL GATEKEEPER', SUPPRESSING THE ABERRANT MUTATIONS THAT DRIVE LYMPHOID MALIGNANCY. 2018 14 2994 25 GENETIC PATHOGENESIS OF INFLAMMATION-ASSOCIATED CANCERS IN DIGESTIVE ORGANS. EPIDEMIOLOGICAL, CLINICAL, AND BIOLOGICAL STUDIES CONVINCINGLY DEMONSTRATE THAT CHRONIC INFLAMMATION PREDISPOSES TO THE DEVELOPMENT OF HUMAN CANCERS. IN DIGESTIVE ORGANS, INFLAMMATION-ASSOCIATED CANCERS INCLUDE COLITIS-ASSOCIATED COLORECTAL CANCERS, HELICOBACTER PYLORI-ASSOCIATED GASTRIC CANCER, AS WELL AS BARRETT'S ESOPHAGUS AND ESOPHAGEAL ADENOCARCINOMA ASSOCIATED WITH CHRONIC DUODENOGASTRIC-ESOPHAGEAL REFLUX. CANCER IS A GENOMIC DISEASE, AND STEPWISE ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS OF TUMOR-RELATED GENES LEADS TO THE DEVELOPMENT OF TUMOR CELLS. RECENT GENOME ANALYSES SHOW THAT GENETIC ALTERATIONS, WHICH ARE EVOKED BY INFLAMMATION, ARE LATENTLY ACCUMULATED IN INFLAMED EPITHELIAL CELLS OF DIGESTIVE ORGANS. PRODUCTION OF REACTIVE OXYGEN AND ABERRANT EXPRESSION OF ACTIVATION-INDUCED CYTIDINE DEAMINASE, A NUCLEOTIDE-EDITING ENZYME, COULD BE INDUCED IN INFLAMED GASTROINTESTINAL EPITHELIAL CELLS AND PLAY A ROLE AS A GENOMIC MODULATOR OF INFLAMMATION-ASSOCIATED CARCINOGENESIS. UNDERSTANDING THE MOLECULAR LINKAGE BETWEEN INFLAMMATION AND GENETIC ALTERATIONS WILL OPEN UP A NEW FIELD OF TUMOR BIOLOGY AND PROVIDE A NOVEL STRATEGY FOR THE PREVENTION OF INFLAMMATION-ASSOCIATED TUMORIGENESIS. 2021 15 2377 27 EPIGENETIC REGULATION OF TUMOR SUPPRESSORS BY HELICOBACTER PYLORI ENHANCES EBV-INDUCED PROLIFERATION OF GASTRIC EPITHELIAL CELLS. HELICOBACTER PYLORI AND EPSTEIN-BARR VIRUS (EBV) ARE TWO WELL-KNOWN CONTRIBUTORS TO CANCER AND CAN ESTABLISH LIFELONG PERSISTENT INFECTION IN THE HOST. THIS LEADS TO CHRONIC INFLAMMATION, WHICH ALSO CONTRIBUTES TO DEVELOPMENT OF CANCER. ASSOCIATION WITH H. PYLORI INCREASES THE RISK OF GASTRIC CARCINOMA, AND COEXISTENCE WITH EBV ENHANCES PROLIFERATION OF INFECTED CELLS. FURTHER, H. PYLORI-EBV COINFECTION CAUSES CHRONIC INFLAMMATION IN PEDIATRIC PATIENTS. WE HAVE ESTABLISHED AN H. PYLORI-EBV COINFECTION MODEL SYSTEM USING HUMAN GASTRIC EPITHELIAL CELLS. WE SHOWED THAT H. PYLORI INFECTION CAN INCREASE THE ONCOGENIC PHENOTYPE OF EBV-INFECTED CELLS AND THAT THE CYTOTOXIN-ASSOCIATED GENE (CAGA) PROTEIN ENCODED BY H. PYLORI STIMULATED EBV-MEDIATED CELL PROLIFERATION IN THIS COINFECTION MODEL SYSTEM. THIS LED TO INCREASED EXPRESSION OF DNA METHYL TRANSFERASES (DNMTS), WHICH REPROGRAMMED CELLULAR TRANSCRIPTIONAL PROFILES, INCLUDING THOSE OF TUMOR SUPPRESSOR GENES (TSGS), THROUGH HYPERMETHYLATION. THESE FINDINGS PROVIDE NEW INSIGHTS INTO A MOLECULAR MECHANISM WHEREBY COOPERATIVITY BETWEEN TWO ONCOGENIC AGENTS LEADS TO ENHANCED ONCOGENIC ACTIVITY OF GASTRIC CANCER CELLS.IMPORTANCE WE HAVE STUDIED THE COOPERATIVITY BETWEEN H. PYLORI AND EBV, TWO KNOWN ONCOGENIC AGENTS. THIS LED TO AN ENHANCED ONCOGENIC PHENOTYPE IN GASTRIC EPITHELIAL CELLS. WE NOW DEMONSTRATE THAT EBV-DRIVEN EPIGENETIC MODIFICATIONS ARE ENHANCED IN THE PRESENCE OF H. PYLORI, MORE SPECIFICALLY, IN THE PRESENCE OF ITS CAGA SECRETORY ANTIGEN. THIS RESULTS IN INCREASED PROLIFERATION OF THE INFECTED GASTRIC CELLS. OUR FINDINGS NOW ELUCIDATE A MOLECULAR MECHANISM WHEREBY EXPRESSION OF CELLULAR DNA METHYL TRANSFERASES IS INDUCED INFLUENCING INFECTION BY EBV. HYPERMETHYLATION OF THE REGULATORY GENOMIC REGIONS OF TUMOR SUPPRESSOR GENES RESULTS IN THEIR SILENCING. THIS DRASTICALLY AFFECTS THE EXPRESSION OF CELL CYCLE, APOPTOSIS, AND DNA REPAIR GENES, WHICH DYSREGULATES THEIR ASSOCIATED PROCESSES, AND PROMOTION OF THE ONCOGENIC PHENOTYPE. 2018 16 207 27 ACTIVATION OF THE TYPE I INTERFERON PATHWAY IN PRIMARY SJOGREN'S SYNDROME. SJOGREN'S SYNDROME (SS), A CHRONIC AUTOIMMUNE SYSTEMIC DISEASE AFFECTING MIDDLE AGED WOMEN, IS CHARACTERIZED BY LYMPHOCYTIC INFILTRATION OF THE SALIVARY AND LACHRYMAL GLANDS RESULTING IN DRY EYES AND DRY MOUTH. RECENT ADVANCES HAVE REVEALED A MAJOR ROLE FOR ACTIVATION OF THE TYPE I INTERFERON (IFN) PATHWAY IN THE PATHOGENESIS OF THE SYNDROME, AS EVIDENCED BY THE INCREASED CIRCULATING TYPE I IFN ACTIVITY AND AN IFN "SIGNATURE" IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMC) AND MINOR SALIVARY GLAND (MSG) BIOPSIES FROM THESE PATIENTS. POLYMORPHISMS IN GENES INVOLVED IN THE IFNALPHA PATHWAY, SUCH AS IRF5 AND STAT4, HAVE BEEN FOUND TO BE ASSOCIATED WITH DISEASE SUSCEPTIBILITY. WHILE THE INITIAL TRIGGERS OF THE INNATE IMMUNE RESPONSE IN SS REMAIN ELUSIVE, PRELIMINARY EVIDENCE SUPPORTS THE ROLE OF INAPPROPRIATELY EXPRESSED ENDOGENOUS LINE-1 (L1) RETROELEMENTS AS POTENTIAL TRIGGERS OF TYPE I IFN ACTIVATION IN SS, POSSIBLY THROUGH TOLL-LIKE RECEPTOR (TLR) DEPENDENT OR INDEPENDENT PATHWAYS. PROTEINS OF THE METHYLATION MACHINERY AND THE APOBEC FAMILY OF CYTIDINE DEAMINASES ARE COORDINATELY OVEREXPRESSED, SUGGESTING THAT THOSE PROTEINS MIGHT CONTRIBUTE TO REGULATION OF THE INAPPROPRIATELY EXPRESSED L1 ENDOGENOUS RETROELEMENTS IN SS. GIVEN THE APPARENT CENTRAL ROLE OF IFNALPHA IN THE PATHOGENESIS OF SS, BLOCKADE OF THIS CYTOKINE MAY BE A RATIONAL THERAPEUTIC APPROACH. IN THE CURRENT REVIEW WE SUMMARIZE THE CURRENT EVIDENCE REGARDING THE POTENTIAL TRIGGERS OF TYPE I IFN ACTIVATION AS WELL AS THE DATA SUPPORTING GENETIC AND EPIGENETIC REGULATION OF THE TYPE I IFN SYSTEM IN SS. 2010 17 3221 19 HELICOBACTER PYLORI AND THE MOLECULAR PATHOGENESIS OF INTESTINAL-TYPE GASTRIC CARCINOMA. GASTRIC CARCINOMA IS AN INFLAMMATION-RELATED CANCER CAUSED BY LONG-TERM INFECTION WITH THE HUMAN BACTERIAL PATHOGEN, HELICOBACTER PYLORI. THE PATTERN OF ACUTE-ON-CHRONIC INFLAMMATION CAUSES PROGRESSIVE MUCOSAL DAMAGE WHICH MAY RESULT IN ATROPHY WITH METAPLASTIC EPITHELIA AND EVENTUALLY GASTRIC CANCER. RECENTLY, IT HAS BEEN RECOGNIZED THAT H. PYLORI CAN ALSO CAUSE GENETIC INSTABILITY SUCH AS DOUBLE-STRANDED DNA BREAKS AND CAN PRODUCE GENE ACTIVATION AND SILENCING VIA EPIGENETIC PATHWAYS. AS GENETIC INSTABILITY IS THE HALLMARK OF CANCER, WE HIGHLIGHT RECENT PROGRESS IN UNDERSTANDING THE GASTRIC CARCINOGENESIS IN RELATION TO H. PYLORI-RELATED INFLAMMATION, H. PYLORI-INDUCED DOUBLE-STRANDED DNA BREAKAGE AND ABERRANT GENE EXPRESSION AS WELL AS THE MECHANISMS AND ROLE OF H. PYLORI-ASSOCIATED EPIGENETIC CHANGE IN GENE EXPRESSION. 2014 18 4409 23 MOLECULAR ANATOMY AND PATHOGENIC ACTIONS OF HELICOBACTER PYLORI CAGA THAT UNDERPIN GASTRIC CARCINOGENESIS. CHRONIC INFECTION WITH HELICOBACTER PYLORI CAGA-POSITIVE STRAINS IS THE STRONGEST RISK FACTOR FOR GASTRIC CANCER. THE CAGA GENE PRODUCT, CAGA, IS DELIVERED INTO GASTRIC EPITHELIAL CELLS VIA THE BACTERIAL TYPE IV SECRETION SYSTEM. DELIVERED CAGA THEN UNDERGOES TYROSINE PHOSPHORYLATION AT THE GLU-PRO-ILE-TYR-ALA (EPIYA) MOTIFS IN ITS C-TERMINAL REGION AND ACTS AS AN ONCOGENIC SCAFFOLD PROTEIN THAT PHYSICALLY INTERACTS WITH MULTIPLE HOST SIGNALING PROTEINS IN BOTH TYROSINE PHOSPHORYLATION-DEPENDENT AND -INDEPENDENT MANNERS. ANALYSIS OF CAGA USING IN VITRO CULTURED GASTRIC EPITHELIAL CELLS HAS INDICATED THAT THE NONPHYSIOLOGICAL SCAFFOLDING ACTIONS OF CAGA CELL-AUTONOMOUSLY PROMOTE THE MALIGNANT TRANSFORMATION OF THE CELLS BY ENDOWING THE CELLS WITH MULTIPLE PHENOTYPIC CANCER HALLMARKS: SUSTAINED PROLIFERATION, EVASION OF GROWTH SUPPRESSORS, INVASIVENESS, RESISTANCE TO CELL DEATH, AND GENOMIC INSTABILITY. TRANSGENIC EXPRESSION OF CAGA IN MICE LEADS TO IN VIVO ONCOGENIC ACTION OF CAGA WITHOUT ANY OVERT INFLAMMATION. THE IN VIVO ONCOGENIC ACTIVITY OF CAGA IS FURTHER POTENTIATED IN THE PRESENCE OF CHRONIC INFLAMMATION. SINCE HELICOBACTER PYLORI INFECTION TRIGGERS A PROINFLAMMATORY RESPONSE IN HOST CELLS, A FEEDFORWARD STIMULATION LOOP THAT AUGMENTS THE ONCOGENIC ACTIONS OF CAGA AND INFLAMMATION IS CREATED IN CAGA-INJECTED GASTRIC MUCOSA. GIVEN THAT HELICOBACTER PYLORI IS NO LONGER COLONIZED IN ESTABLISHED GASTRIC CANCER LESIONS, THE MULTISTEP NATURE OF GASTRIC CANCER DEVELOPMENT SHOULD INCLUDE A "HIT-AND-RUN" PROCESS OF CAGA ACTION. THUS, ACQUISITION OF GENETIC AND EPIGENETIC ALTERATIONS THAT COMPENSATE FOR CAGA-DIRECTED CANCER HALLMARKS MAY BE REQUIRED FOR COMPLETION OF THE "HIT-AND-RUN" PROCESS OF GASTRIC CARCINOGENESIS. 2020 19 3232 17 HELICOBACTER PYLORI-INDUCED SIGNALING PATHWAYS CONTRIBUTE TO INTESTINAL METAPLASIA AND GASTRIC CARCINOGENESIS. HELICOBACTER PYLORI (H. PYLORI) INDUCES CHRONIC GASTRIC INFLAMMATION, ATROPHIC GASTRITIS, INTESTINAL METAPLASIA, AND CANCER. ALTHOUGH THE RISK OF GASTRIC CANCER INCREASES EXPONENTIALLY WITH THE EXTENT OF ATROPHIC GASTRITIS, THE PRECISE MECHANISMS OF GASTRIC CARCINOGENESIS HAVE NOT BEEN FULLY ELUCIDATED. H. PYLORI INDUCES GENETIC AND EPIGENETIC CHANGES IN GASTRIC EPITHELIAL CELLS THROUGH ACTIVATING INTRACELLULAR SIGNALING PATHWAYS IN A CAGPAI-DEPENDENT MANNER. H. PYLORI EVENTUALLY INDUCES GASTRIC CANCER WITH CHROMOSOMAL INSTABILITY (CIN) OR MICROSATELLITE INSTABILITY (MSI), WHICH ARE CLASSIFIED AS TWO MAJOR SUBTYPES OF GASTRIC CANCER. ELUCIDATION OF THE PRECISE MECHANISMS OF GASTRIC CARCINOGENESIS WILL ALSO BE IMPORTANT FOR CANCER THERAPY. 2015 20 3226 24 HELICOBACTER PYLORI INFECTION, ONCOGENIC PATHWAYS AND EPIGENETIC MECHANISMS IN GASTRIC CARCINOGENESIS. CHRONIC COLONIZATION OF THE HUMAN STOMACH BY HELICOBACTER PYLORI, A GRAM-NEGATIVE BACTERIUM, IS THE MAJOR CAUSE OF CHRONIC GASTRITIS, PEPTIC ULCERS AND GASTRIC CANCER. RECENT PROGRESS HAS ELUCIDATED IMPORTANT BACTERIAL AND HOST FACTORS THAT ARE RESPONSIBLE FOR H. PYLORI-INDUCED GASTRIC INFLAMMATION AND GASTRIC MALIGNANCY. H. PYLORI CYTOTOXIN-ASSOCIATED ANTIGEN A IS THE MAJOR ONCOGENIC FACTOR INJECTED INTO HOST CELLS FROM BACTERIA AND IT DISRUPTS EPITHELIAL CELL FUNCTIONS. TOGETHER WITH H. PYLORI CAG PATHOGENICITY ISLAND, IT CAUSES GENERAL INFLAMMATORY STRESS WITHIN GASTRIC MUCOSA AND ACTIVATES MULTIPLE ONCOGENIC PATHWAYS IN EPITHELIAL CELLS. A GROWING LIST OF THESE PATHWAYS INCLUDES NF-KAPPAB, ACTIVATOR PROTEIN-1, PI3K, SIGNAL TRANSDUCERS AND ACTIVATORS OF TRANSCRIPTION 3, WNT/BETA-CATENIN AND CYCLOOXYGENASE 2. H. PYLORI INDUCES EPIGENETIC ALTERATIONS, SUCH AS DNA METHYLATION AND HISTONE MODIFICATION, WHICH PLAY CRITICAL ROLES IN ONCOGENIC TRANSFORMATION. IN ADDITION, INVESTIGATIONS INTO GASTRIC STEM CELL OR PROGENITOR CELL BIOLOGY HAVE SHED LIGHT ON THE MECHANISMS THROUGH WHICH GASTRIC CANCER MAY ORIGINATE. CONTINUED INVESTIGATION IN THESE AREAS WILL YIELD NOVEL INSIGHTS AND HELP TO ELUCIDATE THE MECHANISMS OF BACTERIA-INDUCED CARCINOGENESIS. 2010