1 1730 150 DYSREGULATION OF STEM CELL SIGNALING NETWORK DUE TO GERMLINE MUTATION, SNP, HELICOBACTER PYLORI INFECTION, EPIGENETIC CHANGE AND GENETIC ALTERATION IN GASTRIC CANCER. GENETIC FACTORS, HELICOBACTER PYLORI INFECTION, SALT OVER-UPTAKE, DECREASED VEGETABLE/FRUIT CONSUMPTION, SMOKING, AND METABOLIC SYNDROME ARE RISK FACTORS OF HUMAN GASTRIC CANCER. GERMLINE MUTATIONS OF CDH1 GENE, AND SNPS OF PTPN11 (SHP2), TLR4, IL1B, TNFA, BMP6, GDF15 AND RUNX3 GENES ARE ASSOCIATED WITH GASTRIC CANCER. HELICOBACTER PYLORI ACTIVATES CAGA-SHP2-ERK AND PEPTIDOGLYCAN-NOD1-NFKAPPAB SIGNALING CASCADES IN GASTRIC EPITHELIAL CELLS USING TYPE IV SECRETION SYSTEM, AND ALSO TRAF6-MAP3K7-NFKAPPAB AND TRAF6-MAP3K7-AP-1 SIGNALING CASCADES IN EPITHELIAL AND IMMUNE CELLS THROUGH LIPOPOLYSACCHARIDE RECOGNITION BY TLR2 OR TLR4. IL-1BETA, IL-6, IL-8, TNFALPHA AND IFNGAMMA ARE ELEVATED IN GASTRIC MUCOSA WITH HELICOBACTER PYLORI INFECTION. IL-6 AND TNFALPHA INDUCE UPREGULATION OF WNT5A AND WNT10B, RESPECTIVELY. WNT SIGNALS ARE TRANSDUCED TO BETA-CATENIN-TCF/LEF, RHOA, JNK, PKC, NFAT, AND NLK SIGNALING CASCADES. WNT-BETA-CATENIN-TCF/LEF SIGNALING INDUCES UPREGULATION OF MYC, CCND1, WISP1, FGF20, JAG1 AND DKK1 GENES. NOTCH SIGNALS ARE TRANSDUCED TO CSL-NICD-MAML AND NFKAPPAB SIGNALING CASCADES. FGF SIGNALS ARE TRANSDUCED TO ERK, PI3K-AKT, PKC, AND NFAT SIGNALING CASCADES. HELICOBACTER PYLORI INFECTION INDUCES SHH UPREGULATION IN PARIETAL CELL LINEAGE, WHILE BMP SIGNALS INDUCE IHH UPREGULATION IN PIT CELL LINEAGE. HEDGEHOG SIGNALS INDUCE UPREGULATION OF GLI1, PTCH1, CCND2, FOXL1, JAG2 AND SFRP1 GENES. JAG1 AND JAG2 ACTIVATE NOTCH SIGNALING, WHILE DKK1 AND SFRP1 INHIBIT WNT SIGNALING. STEM CELL SIGNALING NETWORK, CONSISTING OF WNT, NOTCH, FGF, HEDGEHOG AND BMP SIGNALING PATHWAYS, IS ACTIVATED DURING CHRONIC HELICOBACTER PYLORI INFECTION. EPIGENETIC SILENCING OF SFRP1 GENE OCCURS IN THE EARLIER STAGE OF CARCINOGENESIS IN THE STOMACH, WHILE AMPLIFICATION AND OVEREXPRESSION OF FGFR2 GENE IN THE LATER STAGE. DYSREGULATION OF THE STEM CELL SIGNALING NETWORK DUE TO THE ACCUMULATION OF GERMLINE MUTATION, SNP, HELICOBACTER PYLORI INFECTION, EPIGENETIC CHANGE AND GENETIC ALTERATION GIVES RISE TO GASTRIC CANCER. SNP TYPING AND CUSTOM-MADE MICROARRAY ANALYSES ON GENES ENCODING STEM CELL SIGNALING MOLECULES COULD BE UTILIZED FOR THE PERSONALIZED MEDICINE. 2007 2 6758 46 WNT SIGNALING IN STEM CELL BIOLOGY AND REGENERATIVE MEDICINE. WNT FAMILY MEMBERS ARE SECRETED-TYPE GLYCOPROTEINS TO ORCHESTRATE EMBRYOGENESIS, TO MAINTAIN HOMEOSTASIS, AND TO INDUCE PATHOLOGICAL CONDITIONS. FZD1, FZD2, FZD3, FZD4, FZD5, FZD6, FZD7, FZD8, FZD9, FZD10, LRP5, LRP6, AND ROR2 ARE TRANSMEMBRANE RECEPTORS TRANSDUCING WNT SIGNALS BASED ON LIGAND-DEPENDENT PREFERENTIALITY FOR CAVEOLIN- OR CLATHRIN-MEDIATED ENDOCYTOSIS. WNT SIGNALS ARE TRANSDUCED TO CANONICAL PATHWAY FOR CELL FATE DETERMINATION, AND TO NON-CANONICAL PATHWAYS FOR REGULATION OF PLANAR CELL POLARITY, CELL ADHESION, AND MOTILITY. MYC, CCND1, AXIN2, FGF20, WISP1, JAG1, DKK1 AND GLUCAGON ARE TARGET GENES OF CANONICAL WNT SIGNALING CASCADE, WHILE CD44, VIMENTIN AND STX5 ARE TARGET GENES OF NON-CANONICAL WNT SIGNALING CASCADES. HOWEVER, TARGET GENES OF WNT SIGNALING CASCADES ARE DETERMINED IN A CONTEXT-DEPENDENT MANNER DUE TO EXPRESSION PROFILE OF TRANSCRIPTION FACTORS AND EPIGENETIC STATUS. WNT SIGNALING CASCADES NETWORK WITH NOTCH, FGF, BMP AND HEDGEHOG SIGNALING CASCADES TO REGULATE THE BALANCE OF STEM CELLS AND PROGENITOR CELLS. HERE WNT SIGNALING IN EMBRYONIC STEM CELLS, NEURAL STEM CELLS, MESENCHYMAL STEM CELLS, HEMATOPOIETIC STEM CELLS, AND INTESTINAL STEM CELLS WILL BE REVIEWED. WNT3, WNT5A AND WNT10B ARE EXPRESSED IN UNDIFFERENTIATED HUMAN EMBRYONIC STEM CELLS, WHILE WNT6, WNT8B AND WNT10B IN ENDODERM PRECURSOR CELLS. WNT6 IS EXPRESSED IN INTESTINAL CRYPT REGION FOR STEM OR PROGENITOR CELLS. TNF/ALPHA-WNT10B SIGNALING IS A NEGATIVE FEEDBACK LOOP TO MAINTAIN HOMEOSTASIS OF ADIPOSE TISSUE AND GASTROINTESTINAL MUCOSA WITH CHRONIC INFLAMMATION. RECOMBINANT WNT PROTEIN OR WNT MIMETIC (CIRCULAR PEPTIDE, SMALL MOLECULE COMPOUND, OR RNA APTAMER) IN COMBINATION WITH NOTCH MIMETIC, FGF PROTEIN, AND BMP PROTEIN OPENS A NEW WINDOW TO TISSUE ENGINEERING FOR REGENERATIVE MEDICINE. 2008 3 6756 38 WNT ANTAGONIST, SFRP1, IS HEDGEHOG SIGNALING TARGET. HEDGEHOG AND WNT SIGNALING PATHWAYS NETWORK TOGETHER DURING EMBRYOGENESIS AND CARCINOGENESIS. HEDGEHOG SIGNALING IN INTESTINAL EPITHELIUM REPRESSES CANONICAL WNT SIGNALING TO RESTRICT EXPRESSION OF WNT TARGET GENES TO STEM OR PROGENITOR CELLS; HOWEVER, THE MECHANISM REMAINS UNCLEAR. THE HEDGEHOG SIGNAL IS TRANSDUCED TO GLI FAMILY TRANSCRIPTION FACTORS THOUGH PATCHED RECEPTOR, SMOOTHENED SIGNAL TRANSDUCER, AND OTHER SIGNALING COMPONENTS, SUCH AS KIF27, KIF7, STK36, SUFU, AND DZIP1. HERE, WE SEARCHED FOR THE GLI-BINDING SITE WITHIN THE PROMOTER REGION OF GENES ENCODING SECRETED-TYPE WNT SIGNAL INHIBITORS, INCLUDING SFRP1, SFRP2, SFRP3, SFRP4, SFRP5, DKK1, DKK2, DKK3, DKK4, AND WIF1. THE GLI-BINDING SITE WAS IDENTIFIED WITHIN THE HUMAN SFRP1 PROMOTER BASED ON BIOINFORMATICS AND HUMAN INTELLIGENCE. THE CHIMPANZEE SFRP1 GENE WAS IDENTIFIED WITHIN THE NW_110515.1 GENOME SEQUENCE. THE GLI-BINDING SITE OF THE HUMAN SFRP1 PROMOTER WAS CONSERVED IN CHIMPANZEE SFRP1, MOUSE SFRP1, AND RAT SFRP1 PROMOTERS. SFRP1 IS THE EVOLUTIONARILY CONSERVED TARGET OF THE HEDGEHOG-GLI SIGNALING PATHWAY. EXPRESSION DOMAIN ANALYSES BASED ON TEXT MINING REVEALED THAT INDIAN HEDGEHOG (IHH), SFRP1, AND WNT6 ARE EXPRESSED IN DIFFERENTIATED INTESTINAL EPITHELIAL CELLS, MESENCHYMAL CELLS, AND STEM/PROGENITOR CELLS, RESPECTIVELY. HEDGEHOG IS SECRETED FROM DIFFERENTIATED EPITHELIAL CELLS TO INDUCE SFRP1 EXPRESSION IN MESENCHYMAL CELLS, WHICH KEEPS DIFFERENTIATED EPITHELIAL CELLS AWAY FROM THE EFFECTS OF CANONICAL WNT SIGNALING. THESE FACTS INDICATE THAT SFRP1 IS THE HEDGEHOG TARGET TO CONFINE CANONICAL WNT SIGNALING WITHIN STEM OR PROGENITOR CELLS. THEREFORE, EPIGENETIC CPG HYPERMETHYLATION OF THE SFRP1 PROMOTER DURING CHRONIC PERSISTENT INFLAMMATION AND AGING LEADS TO THE OCCURRENCE OF GASTROINTESTINAL CANCERS, SUCH AS COLORECTAL CANCER AND GASTRIC CANCER, THROUGH THE BREAKDOWN OF HEDGEHOG-DEPENDENT WNT SIGNAL INHIBITION. 2006 4 2379 30 EPIGENETIC REGULATION OF WNT PATHWAY ANTAGONISTS IN HUMAN GLIOBLASTOMA MULTIFORME. EPIGENETIC INACTIVATION OF TUMOR SUPPRESSOR GENES IS COMMON IN HUMAN CANCER. USING A LARGE-SCALE WHOLE-GENOME APPROACH IN AN EARLIER STUDY, THE AUTHORS IDENTIFIED EPIGENETICALLY SILENCED GENES WITH POTENTIAL TUMOR SUPPRESSOR FUNCTION IN GLIOBLASTOMA (GBM). THREE GENES IDENTIFIED IN THIS ANALYSIS-DKK1, SFRP1, AND WIF1-ARE POTENT INHIBITORS OF THE WNT SIGNAL TRANSDUCTION PATHWAY. HERE, THE AUTHORS CONFIRM DECREASED EXPRESSION OF THESE GENES IN GBM TUMOR TISSUE SAMPLES RELATIVE TO NONTUMOR BRAIN TISSUE SAMPLES USING REAL-TIME PCR. THEY THEN SHOW THAT EXPRESSION OF ALL 3 GENES IS RESTORED IN T98 GBM CELLS BY TREATMENT WITH THE HISTONE DEACETYLASE INHIBITOR TRICHOSTATIN A (TSA), BUT ONLY DKK1 EXPRESSION IS RESTORED BY TREATMENT WITH THE DEMETHYLATING AGENT 5-AZACYTIDINE. BISULFITE SEQUENCING DID NOT REVEAL SIGNIFICANT METHYLATION IN THE PROMOTER REGION OF DKK1, WHEREAS HISTONE ACETYLATION AND CHROMATIN ACCESSIBILITY INCREASED SIGNIFICANTLY FOR ALL 3 GENES AFTER TSA TREATMENT. ECTOPIC EXPRESSION OF DKK1 SIGNIFICANTLY REDUCES COLONY FORMATION AND INCREASES CHEMOTHERAPY-INDUCED APOPTOSIS IN T98 CELLS. ECTOPIC EXPRESSION OF THE CANONICAL WNT PATHWAY INHIBITORS WIF1 AND SFRP1 SHOWS A RELATIVE LACK OF RESPONSE. CHRONIC WNT3A STIMULATION ONLY PARTIALLY REVERSES GROWTH SUPPRESSION AFTER DKK1 REEXPRESSION, WHEREAS A SPECIFIC INHIBITOR OF THE JNK PATHWAY SIGNIFICANTLY REVERSES THE EFFECT OF DKK1 REEXPRESSION ON COLONY FORMATION AND APOPTOSIS IN T98 CELLS. THESE RESULTS SUPPORT A POTENTIAL GROWTH-SUPPRESSIVE FUNCTION FOR EPIGENETICALLY SILENCED DKK1 IN GBM AND SUGGEST THAT DKK1 RESTORATION COULD MODULATE WNT SIGNALING THROUGH BOTH CANONICAL AND NONCANONICAL PATHWAYS. 2010 5 2377 32 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 6 3226 35 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 7 2943 26 GENETIC AND EPIGENETIC ALTERATIONS OF TUMOR SUPPRESSOR AND TUMOR-RELATED GENES IN GASTRIC CANCER. BOTH GENETIC AND EPIGENETIC ALTERATIONS OF TUMOR SUPPRESSOR AND TUMOR-RELATED GENES INVOLVED IN THE PATHOGENESIS OF GASTRIC CANCER ARE REVIEWED HERE, AND MOLECULAR PATHWAYS OF GASTRIC CARCINOGENESIS ARE PROPOSED. GASTRIC CARCINOMAS ARE BELIEVED TO EVOLVE FROM NATIVE GASTRIC MUCOSA OR INTESTINAL METAPLASTIC MUCOSA THAT UNDERGOES GENETIC AND EPIGENETIC ALTERATIONS INVOLVING EITHER THE SUPPRESSOR PATHWAY (DEFECTS IN TUMOR SUPPRESSOR GENES) OR MUTATOR PATHWAY (DEFECTS IN DNA MISMATCH REPAIR GENES). METHYLATION OF E-CADHERIN IN NATIVE GASTRIC MUCOSA RESULTS IN UNDIFFERENTIATED CARCINOMAS (SUPPRESSOR PATHWAY), WHILE METHYLATION OF HMLHI RESULTS IN DIFFERENTIATED FOVEOLAR-TYPE CARCINOMAS (MUTATOR PATHWAY). THE MAJORITY OF DIFFERENTIATED GASTRIC CARCINOMAS HOWEVER, ARISE FROM INTESTINAL METAPLASTIC MUCOSA AND EXHIBIT STRUCTURAL ALTERATIONS OF TUMOR SUPPRESSOR GENES, ESPECIALLY P53. THEY APPEAR TO BE RELATED TO CHRONIC INJURY, PERHAPS DUE TO HELICOBACTER PYLORI INFECTION. APPROXIMATELY 20% OF DIFFERENTIATED CARCINOMAS (ORDINARY-TYPE) HAVE EVIDENCE OF MUTATOR PATHWAY TUMORIGENESIS. MUTATIONS OF E-CADHERIN ARE MAINLY INVOLVED IN THE PROGRESSION OF DIFFERENTIATED CARCINOMAS TO UNDIFFERENTIATED TUMORS. THE MOLECULAR PATHWAYS OF GASTRIC CARCINOGENESIS DEPEND ON THE HISTOLOGICAL BACKGROUND, AND GASTRIC CARCINOMAS SHOW DISTINCT BIOLOGICAL BEHAVIORS AS A RESULT OF DISCERNIBLE CELLULAR GENETIC AND EPIGENETIC ALTERATIONS. 2002 8 2435 31 EPIGENETIC SILENCING OF SFRP1 ACTIVATES THE CANONICAL WNT PATHWAY AND CONTRIBUTES TO INCREASED CELL GROWTH AND PROLIFERATION IN HEPATOCELLULAR CARCINOMA. THE WNT PATHWAY IS A KEY REGULATOR OF EMBRYONIC DEVELOPMENT AND STEM CELLS, AND ITS ABERRANT ACTIVATION IS ASSOCIATED WITH HUMAN MALIGNANCIES, MOST NOTABLY HEPATOCELLULAR CARCINOMA (HCC). EPIGENETIC DEREGULATION OF THE GENES ENCODING THE SECRETED FRIZZLED-RELATED PROTEINS (SFRPS), THE WNT SIGNALLING ANTAGONISTS, HAS BEEN LINKED WITH ABERRANT HYPERACTIVATION OF THE WNT SIGNALLING IN HCC CELLS; HOWEVER, THE PRECISE UNDERLYING MECHANISM REMAINS ELUSIVE. WE INVESTIGATED THE METHYLATION PROFILES OF WNT ANTAGONISTS IN LIVER SAMPLES OF DIFFERENT STAGES OF HCC DEVELOPMENT AND LIVER CANCER CELL LINES AND STUDIED THE FUNCTIONAL IMPACT OF ABERRANT EPIGENETIC SILENCING OF SFRPS ON THE CANONICAL WNT PATHWAY AND CELL VIABILITY. WE FOUND THAT THE SFRP1 GENE ENCODING THE SUBUNIT IS A FREQUENT TARGET OF ABERRANT DNA HYPERMETHYLATION AND SILENCING IN HCC TUMOURS, WHEREAS OTHER EXTRACELLULAR WNT ANTAGONISTS, WIF1 AND DKK3, EXHIBITED NO METHYLATION IN TUMOUR CELLS, CONSISTENT WITH THE NOTION THAT ABERRANT METHYLATION EVENTS IN CANCER CELLS ARE NON-RANDOMLY DISTRIBUTED AMONG THE GENES AND THAT THERE IS A STRONG PREFERENCE FOR HYPERMETHYLATION OF SPECIFIC GENES IN HCC. IN ADDITION, BY COMPARING SFRP1 METHYLATION STATUS IN HCC TUMOURS WITH NORMAL, CIRRHOTIC AND CHRONIC HEPATITIS LIVER TISSUES, WE IDENTIFIED SFRP1 GENE AS A POTENTIAL EARLY MARKER OF HCC. THE RESTORATION OF SFRP1 EXPRESSION IN CANCER CELLS BY ECTOPIC EXPRESSION INHIBITED WNT ACTIVITY ACCOMPANIED WITH DESTABILIZATION OF BETA-CATENIN AND DOWNREGULATION OF C-MYC AND CYCLIN D1, THE KNOWN DOWNSTREAM TARGETS OF WNT PATHWAY. IMPORTANTLY, RESTORING SFRP1 LEVELS IN CANCER CELLS INHIBITED CELL GROWTH AND INDUCED APOPTOTIC CELL DEATH. THIS STUDY SUPPORTS THE CRITICAL ROLE FOR SFRP1 SILENCING IN HEPATOCELLULAR CARCINOMA AND REINFORCES THE IMPORTANCE OF THE WNT ANTAGONISTS IN PREVENTING ONCOGENIC STABILIZATION OF BETA-CATENIN AND CHRONIC ACTIVATION OF THE CANONICAL WNT PATHWAY, SUGGESTING THAT SFRP1 MAY BE AN ATTRACTIVE TARGET FOR EARLY CANCER DETECTION AND THERAPEUTIC INTERVENTION. 2012 9 1483 23 DKK1 IS EPIGENETICALLY DOWNREGULATED BY PROMOTER METHYLATION AND INHIBITS BILE ACID-INDUCED GASTRIC INTESTINAL METAPLASIA. DICKKOPF-RELATED PROTEIN 1 (DKK1) IS ESSENTIAL TO GASTRIC CANCER AS AN INHIBITOR OF WNT SIGNALING. GASTRIC INTESTINAL METAPLASIA (GIM) IS AN IMPORTANT PRECANCEROUS LESION OF GASTRIC CANCER THAT CAN BE ACTIVATED BY BILE ACID REFLUX AND CHRONIC INFLAMMATION. HOWEVER, THE EXACT MECHANISM OF DKK1 IN BILE ACID-INDUCED GIM HAS NOT BEEN COMPLETELY ELUCIDATED. WE AIMED TO EXPLORE THE EPIGENETIC ALTERATIONS AND BIOLOGICAL FUNCTIONS OF DKK1 IN THE DEVELOPMENT OF GIM. IN THE PRESENT STUDY, BILE ACID WAS FOUND TO INDUCE THE EXPRESSION OF INTESTINAL MARKERS IN GASTRIC EPITHELIAL CELLS, WHEREAS DKK1 WAS DOWNREGULATED IN RESPONSE TO BILE ACID STIMULATION. THE MRNA AND PROTEIN EXPRESSION LEVELS OF DKK1 WERE DECREASED IN GIM TISSUES AS EVIDENCED BY QRT-PCR AND IMMUNOHISTOCHEMICAL STAINING. SURPRISINGLY, THE METHYLATION OF THE DKK1 PROMOTER INCREASED IN GIM TISSUES, AND WE DISCOVERED 28 DIFFERENTIAL METHYLATION SITES OF THE DKK1 PROMOTER IN GIM TISSUES. BILE ACID WAS ABLE TO INDUCE THE PARTIAL METHYLATION OF THE DKK1 PROMOTER, WHILE 5-AZA COULD INCREASE DKK1 EXPRESSION AS WELL AS DECREASE INTESTINAL MARKERS EXPRESSION IN GASTRIC EPITHELIAL CELLS. IN CONCLUSION, THE PROMOTER METHYLATION AND DOWNREGULATION OF DKK1 MIGHT PLAY IMPORTANT ROLES IN THE DEVELOPMENT OF GIM, ESPECIALLY BILE ACID-INDUCED GIM. 2020 10 5668 29 SFRP1 EXPRESSION REGULATES WNT SIGNALING IN CHRONIC MYELOID LEUKEMIA K562 CELLS. BACKGROUND: WNT SIGNALING CASCADES PLAY IMPORTANT ROLES IN CELL FATE DECISIONS AND THEIR DEREGULATION HAS BEEN DOCUMENTED IN MANY DISEASES, INCLUDING MALIGNANT TUMORS AND LEUKEMIA. ONE MECHANISM OF ABERRANT WNT SIGNALING IS THE SILENCING OF WNT INHIBITORS THROUGH EPIGENETIC MECHANISMS. THE SFRPS ARE ONE OF THE MOST STUDIED WNT INHIBITORS; AND THE SFRP1 LOSS IS KNOWN IN MANY HEMATOLOGICAL MALIGNANCIES. THEREFORE, WE AIMED TO COMPARE THE EXPRESSION OF WNT RELATED GENES IN THE PRESENCE AND ABSENCE OF SFRP1 IN A CHRONIC MYELOID LEUKEMIA (CML) CELL LINE. OBJECTIVE: IT IS IMPORTANT TO UNDERSTAND HOW SFRP1 AND SFRP1 PERFORM THEIR EFFECTS ON CML TO DESIGN NEW AGENTS AND STRATEGIES FOR RESISTANT AND ADVANCED FORMS OF CML. MATERIALS AND METHODS: WE USED K562 CELLS, WHICH NORMALLY DO NOT EXPRESS SFRP1 AND ITS SFRP1 EXPRESSING SUBCLONE K562S. TOTAL RNA WAS ISOLATED FROM K562 AND K562S CELL LINES AND CONVERTED TO CDNA. PCR ARRAY EXPERIMENTS WERE PERFORMED USING HUMAN WNT SIGNALING PATHWAY PLUS RT2 PROFILER KIT. WNT SIGNALING PATHWAY ACTIVATION WAS STUDIED BY WESTERN BLOT FOR DOWNSTREAM SIGNALING TARGETS. RESULTS: THE WNT3, LRP6, PRICKLE1 AND BTRC EXPRESSIONS WERE SIGNIFICANTLY DECREASED IN THE PRESENCE OF SFRP1; WHILE WNT5B INCREASED. THE SFRP1 EXPRESSION INHIBITED STABILIZATION OF TOTAL BETA-CATENIN PROTEIN AND DOWNSTREAM EFFECTOR PHOSPHORYLATION OF NONCANONICAL WNT/PCP SIGNALING; WHEREAS CA2+/PKC SIGNALING REMAINED ACTIVE. CONCLUSION: THE RESULTS SUGGEST THAT SFRP1 COULD BE A PROMISING THERAPEUTIC ANTICANCER AGENT. DEFINING THESE PATHWAY INTERACTIONS IS CRUCIAL FOR DESIGNING NEW AGENTS RESISTANT AND ADVANCED FORMS OF CML. 2022 11 2437 21 EPIGENETIC SILENCING OF SONIC HEDGEHOG ELICITS ANTITUMOR IMMUNE RESPONSE AND SUPPRESSES TUMOR GROWTH BY INHIBITING THE HEDGEHOG SIGNALING PATHWAY IN METASTATIC SPINE TUMORS IN SPRAGUE-DAWLEY RATS. BACKGROUND: PATIENTS WITH METASTATIC SPINE TUMORS MAY SUFFER FROM PAIN OR NEUROLOGIC DEFICIT, AND THE DISEASE MAY BE DETECTED IN PATIENTS WITH A KNOWN MALIGNANCY. SONIC HEDGEHOG (SHH) HAS RECEIVED SPECIAL ATTENTION DUE TO ITS ROLE IN CANCERS. THEREFORE, THIS STUDY INVESTIGATED THE EFFECTS OF EPIGENETIC SILENCING OF SHH ON ANTITUMOR IMMUNE RESPONSE AND TUMOR GROWTH BY REGULATING THE HEDGEHOG (HH) SIGNALING PATHWAY IN METASTATIC SPINE TUMORS. METHODS: RAT MODELS OF METASTATIC SPINE TUMORS WERE SUCCESSFULLY ESTABLISHED. WE FIRST CALCULATED THE TUMOR VOLUME AND THE INHIBITION RATE OF TUMOR GROWTH TO INVESTIGATE THE EFFECT OF SHH ON TUMOR GROWTH. AFTERWARDS, IMMUNOHISTOCHEMISTRY WAS USED TO DETERMINE WHETHER PROLIFERATION WAS DELAYED BY SHH DEPLETION, AND THE 3-(4,5-DIMETHYLTHIAZOL-2-YL)-2,5-DIPHENYLTETRAZOLIUM BROMIDE ASSAY WAS CONDUCTED TO TEST THE CHANGES IN THE LYMPHOCYTE TRANSFORMATION RATE IN THE SPLEEN TRIGGERED BY SHH SILENCING. THEN, THE INFLUENCE OF SHH DEPLETION ON IMMUNE FUNCTION WAS INVESTIGATED. LATER, QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION AND WESTERN BLOT ASSAY WERE PERFORMED TO EXPLORE THE HH SIGNALING PATHWAY-RELATED FACTORS. FINALLY, WE ADDED THE HH SIGNALING PATHWAY INHIBITOR, GDC-0449, TO CONFIRM THE ROLE OF THE PATHWAY IN TUMOR PROGRESSION. RESULTS: INITIALLY, WE OBSERVED THAT SHH DEPLETION WAS A NEGATIVE FACTOR FOR TUMOR GROWTH. AFTERWARDS, IT WAS REVEALED THAT EPIGENETIC SILENCING OF SHH SERVED AS AN INHIBITOR FACTOR FOR THE FUNCTION OF SPLEEN LYMPHOCYTE TRANSFORMATION AND INFLAMMATION WHILE PROMOTING ANTITUMOR IMMUNE FUNCTION. CONCLUSION: OUR PRELIMINARY RESULTS INDICATE THAT EPIGENETIC SILENCING OF SHH ELICITS AN ANTITUMOR IMMUNE RESPONSE AND SUPPRESSES TUMOR GROWTH BY INHIBITING THE HH SIGNALING PATHWAY IN METASTATIC SPINE TUMORS. 2018 12 3642 28 INCREASED H3K4ME3 METHYLATION AND DECREASED MIR-7113-5P EXPRESSION LEAD TO ENHANCED WNT/BETA-CATENIN SIGNALING IN IMMUNE CELLS FROM PTSD PATIENTS LEADING TO INFLAMMATORY PHENOTYPE. BACKGROUND: POSTTRAUMATIC STRESS DISORDER (PTSD) IS A PSYCHIATRIC DISORDER ACCOMPANIED BY CHRONIC PERIPHERAL INFLAMMATION. WHAT TRIGGERS INFLAMMATION IN PTSD IS CURRENTLY UNCLEAR. IN THE PRESENT STUDY, WE IDENTIFIED POTENTIAL DEFECTS IN SIGNALING PATHWAYS IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) FROM INDIVIDUALS WITH PTSD. METHODS: RNASEQ (5 SAMPLES EACH FOR CONTROLS AND PTSD), CHIPSEQ (5 SAMPLES EACH) AND MIRNA ARRAY (6 SAMPLES EACH) WERE USED IN COMBINATION WITH BIOINFORMATICS TOOLS TO IDENTIFY DYSREGULATED GENES IN PBMCS. REAL TIME QRT-PCR (24 SAMPLES EACH) AND IN VITRO ASSAYS WERE EMPLOYED TO VALIDATE OUR PRIMARY FINDINGS AND HYPOTHESIS. RESULTS: BY RNA-SEQ ANALYSIS OF PBMCS, WE FOUND THAT WNT SIGNALING PATHWAY WAS UPREGULATED IN PTSD WHEN COMPARED TO NORMAL CONTROLS. SPECIFICALLY, WE FOUND INCREASED EXPRESSION OF WNT10B IN THE PTSD GROUP WHEN COMPARED TO CONTROLS. OUR FINDINGS WERE CONFIRMED USING NCBI'S GEO DATABASE INVOLVING A LARGER SAMPLE SIZE. ADDITIONALLY, IN VITRO ACTIVATION STUDIES REVEALED THAT ACTIVATED BUT NOT NAIVE PBMCS FROM CONTROL INDIVIDUALS EXPRESSED MORE IFNGAMMA IN THE PRESENCE OF RECOMBINANT WNT10B SUGGESTING THAT WNT SIGNALING PLAYED A CRUCIAL ROLE IN EXACERBATING INFLAMMATION. NEXT, WE INVESTIGATED THE MECHANISM OF INDUCTION OF WNT10B AND FOUND THAT INCREASED EXPRESSION OF WNT10B MAY RESULT FROM EPIGENETIC MODULATION INVOLVING DOWNREGULATION OF HSA-MIR-7113-5P WHICH TARGETED WNT10B. FURTHERMORE, WE ALSO OBSERVED THAT WNT10B OVEREXPRESSION WAS LINKED TO HIGHER EXPRESSION OF H3K4ME3 HISTONE MODIFICATION AROUND THE PROMOTOR OF WNT10B. ADDITIONALLY, KNOCKDOWN OF HISTONE DEMETHYLASE SPECIFIC TO H3K4ME3, USING SIRNA, LED TO INCREASED EXPRESSION OF WNT10B PROVIDING CONCLUSIVE EVIDENCE THAT H3K4ME3 INDEED CONTROLLED WNT10B EXPRESSION. CONCLUSIONS: IN SUMMARY, OUR DATA DEMONSTRATE FOR THE FIRST TIME THAT WNT SIGNALING PATHWAY IS UPREGULATED IN PBMCS OF PTSD PATIENTS RESULTING FROM EPIGENETIC CHANGES INVOLVING MICRORNA DYSREGULATION AND HISTONE MODIFICATIONS, WHICH IN TURN MAY PROMOTE THE INFLAMMATORY PHENOTYPE IN SUCH CELLS. 2020 13 6841 36 [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 14 1540 31 DNA METHYLATION IN GASTRIC CANCER, RELATED TO HELICOBACTER PYLORI AND EPSTEIN-BARR VIRUS. GASTRIC CANCER IS A LEADING CAUSE OF CANCER DEATH WORLDWIDE, AND SIGNIFICANT EFFORT HAS BEEN FOCUSED ON CLARIFYING THE PATHOLOGY OF GASTRIC CANCER. IN PARTICULAR, THE DEVELOPMENT OF GENOME-WIDE ANALYSIS TOOLS HAS ENABLED THE DETECTION OF GENETIC AND EPIGENETIC ALTERATIONS IN GASTRIC CANCER; FOR EXAMPLE, ABERRANT DNA METHYLATION IN GENE PROMOTER REGIONS IS THOUGHT TO PLAY A CRUCIAL ROLE IN GASTRIC CARCINOGENESIS. THE ETIOLOGICAL VIEWPOINT IS ALSO ESSENTIAL FOR THE STUDY OF GASTRIC CANCERS, AND TWO DISTINCT PATHOGENS, HELICOBACTER PYLORI (H. PYLORI) AND EPSTEIN-BARR VIRUS (EBV), ARE KNOWN TO PARTICIPATE IN GASTRIC CARCINOGENESIS. CHRONIC INFLAMMATION OF THE GASTRIC EPITHELIUM DUE TO H. PYLORI INFECTION INDUCES ABERRANT POLYCLONAL METHYLATION THAT MAY LEAD TO AN INCREASED RISK OF GASTRIC CANCER. IN ADDITION, EBV INFECTION IS KNOWN TO CAUSE EXTENSIVE METHYLATION, AND EBV-POSITIVE GASTRIC CANCERS DISPLAY A HIGH METHYLATION EPIGENOTYPE, IN WHICH ABERRANT METHYLATION EXTENDS TO NOT ONLY POLYCOMB REPRESSIVE COMPLEX (PRC)-TARGET GENES IN EMBRYONIC STEM CELLS BUT ALSO NON-PRC-TARGET GENES. HERE, WE REVIEW ABERRANT DNA METHYLATION IN GASTRIC CANCER AND THE ASSOCIATION BETWEEN METHYLATION AND INFECTION WITH H. PYLORI AND EBV. 2014 15 4162 26 MECP2 REGULATES PTCH1 EXPRESSION THROUGH DNA METHYLATION IN RHEUMATOID ARTHRITIS. RHEUMATOID ARTHRITIS (RA) IS A CHRONIC AUTOIMMUNE INFLAMMATORY DISEASE, IN WHICH PATHOGENESIS IS NOT CLEAR. MANY RESEARCH DEMONSTRATED THAT FIBROBLAST-LIKE SYNOVIOCYTES (FLSS) PLAY A KEY ROLE IN RA PATHOGENESIS, JOIN IN THE CARTILAGE INJURY AND HYPERPLASIA OF THE SYNOVIUM, AND CONTRIBUTE TO THE RELEASE OF INFLAMMATORY CYTOKINES. WE USED ADJUVANT ARTHRITIS (AA) RATS AS RA ANIMAL MODELS. THE METHYL-CPG-BINDING PROTEIN 2 (MECP2) ENABLES THE SUPPRESSED CHROMATIN STRUCTURE TO BE SELECTIVELY DETECTED IN AA FLSS. OVEREXPRESSION OF THIS PROTEIN LEADS TO AN INCREASE OF INTEGRAL METHYLATION LEVELS. SOME RESEARCH HAS CONFIRMED THE HEDGEHOG (HH) SIGNALING PATHWAY PLAYS AN IMPORTANT ROLE IN RA PATHOGENESIS; FURTHERMORE, PATCHED 1 (PTCH1) IS A NEGATIVE FRACTION OF HH SIGNALING PATHWAY. WE USED 5-AZA-2'-DEOXYCYTIDINE (5-AZADC) AS DNA METHYLATION INHIBITOR. IN OUR RESEARCH, WE FOUND MECP2 REDUCED PTCH1 EXPRESSION IN AA FLSS; 5-AZADC OBSTRUCTED THE LOSS OF PTCH1 EXPRESSION. 5-AZADC, TREATMENT OF AA FLSS, ALSO BLOCKS THE RELEASE OF INFLAMMATORY CYTOKINES. IN ORDER TO PROBE THE POTENTIAL MOLECULAR MECHANISM, WE ASSUMED THE EPIGENETIC PARTICIPATION IN THE REGULATION OF PTCH1. RESULTS DEMONSTRATED THAT PTCH1 HYPERMETHYLATION IS RELATED TO THE PERSISTENT FLS ACTIVATION AND INFLAMMATION IN AA RATS. KNOCKDOWN OF MECP2 USING SMALL-INTERFERING RNA TECHNIQUE ADDED PTCH1 EXPRESSION IN AA FLSS. OUR RESULTS INDICATE THAT DNA METHYLATION MAY OFFER MOLECULE MECHANISMS, AND THE REDUCED PTCH1 METHYLATION LEVEL COULD REGULATE INFLAMMATION THROUGH KNOCKDOWN OF MECP2. GRAPHICAL ABSTRACT PTCH1 IS AN INHIBITORY PROTEIN OF THE HEDGEHOG SIGNALING PATHWAY. INCREASED EXPRESSION OF PTCH1 CAN INHIBIT THE EXPRESSION OF GLI1 AND SHH, THEREBY INHIBITING THE ACTIVATION OF HEDGEHOG SIGNALING PATHWAY. INACTIVATED HEDGEHOG SIGNALING PATHWAY INHIBITS THE SECRETION OF IL-6 AND TNF-ALPHA. MECP2 MEDIATES HYPERMETHYLATION OF PTCH1 GENE AND DECREASES THE EXPRESSION OF PTCH1 PROTEIN, THUS ACTIVATING HEDGEHOG SIGNALING PATHWAY AND INCREASING SECRETION OF IL-6 AND TNF-ALPHA. 2017 16 2811 45 FGFR2-RELATED PATHOGENESIS AND FGFR2-TARGETED THERAPEUTICS (REVIEW). FGFR2 GENE AT HUMAN CHROMOSOME 10Q26 ENCODES FGFR2B AND FGFR2C ISOFORMS FUNCTIONING AS FGF RECEPTORS WITH DISTINCT EXPRESSION DOMAIN AND LIGAND SPECIFICITY. FGFR2 PLAYS ONCOGENIC AND ANTI-ONCOGENIC ROLES IN A CONTEXT-DEPENDENT MANNER. SINGLE NUCLEOTIDE POLYMORPHISMS (SNPS) WITHIN INTRON 2 OF FGFR2 GENE ARE ASSOCIATED WITH BREAST CANCER THROUGH ALLELIC FGFR2 UPREGULATION. MISSENSE MUTATIONS OR COPY NUMBER GAINS OF FGFR2 GENE OCCUR IN BREAST CANCER AND GASTRIC CANCER TO ACTIVATE FGFR2 SIGNALING. ABERRANT FGFR2 SIGNALING ACTIVATION INDUCES PROLIFERATION AND SURVIVAL OF TUMOR CELLS. THE CLASS SWITCH FROM FGFR2B TO FGFR2C OCCURS DURING PROGRESSION OF PROSTATE CANCER AND BLADDER CANCER BECAUSE OF SPLICEOSOME DYSREGULATION. IN ADDITION, EPIDERMAL FGFR2B KNOCKOUT MICE SHOW INCREASED SENSITIVITY TO CHEMICAL CARCINOGENESIS PARTLY DUE TO THE FAILURE OF NFE2L2 (NRF2)-MEDIATED DETOXIFICATION OF REACTIVE OXYGEN SPECIES (ROS). LOSS OF FGFR2B SIGNALING INDUCES EPITHELIAL-TO-MESENCHYMAL TRANSITION (EMT) AND UNRULY ROS. FGFR2 SIGNALING DYSREGULATION DUE TO THE ACCUMULATION OF EPIGENETIC MODIFICATIONS AND GENETIC ALTERATIONS DURING CHRONIC INFLAMMATION, SMOKING, INCREASED CALORIC UPTAKE, AND DECREASED EXERCISE LEADS TO CARCINOGENESIS. PD173074, SU5402, AZD2171, AND KI23057 ARE SMALL-MOLECULE FGFR INHIBITORS. HUMAN ANTIBODY, PEPTIDE MIMETIC, RNA APTAMER, SIRNA, AND SYNTHETIC MICRORNA (MIRNA) ARE EMERGING TECHNOLOGIES TO BE APPLIED FOR CANCER THERAPEUTICS TARGETED TO FGFR2. BECAUSE NOVEL SEQUENCE TECHNOLOGY AND PETA-SCALE SUPER-COMPUTER ARE OPENING UP THE SEQUENCE ERA FOLLOWING THE GENOME ERA, PERSONALIZED MEDICINE PRESCRIBING TARGETED DRUGS BASED ON GERMLINE AND/OR SOMATIC GENOMIC INFORMATION IS COMING REALITY. APPLICATION OF FGFR2 INHIBITORS FOR CANCER TREATMENT IN PATIENTS WITH FGFR2 MUTATION OR GENE AMPLIFICATION IS BENEFICIAL; HOWEVER, THAT FOR CANCER PREVENTION IN PEOPLE WITH FGFR2 RISK ALLELE MIGHT BE DISADVANTAGEOUS DUE TO THE IMPEDIMENT OF A CYTOPROTECTIVE MECHANISM AGAINST OXIDATIVE STRESS. 2009 17 3225 33 HELICOBACTER PYLORI INFECTION INTRODUCES DNA DOUBLE-STRAND BREAKS IN HOST CELLS. GASTRIC CANCER IS AN INFLAMMATION-RELATED MALIGNANCY RELATED TO LONG-STANDING ACUTE AND CHRONIC INFLAMMATION CAUSED BY INFECTION WITH THE HUMAN BACTERIAL PATHOGEN HELICOBACTER PYLORI. INFLAMMATION CAN RESULT IN GENOMIC INSTABILITY. HOWEVER, THERE ARE CONSIDERABLE DATA THAT H. PYLORI ITSELF CAN ALSO PRODUCE GENOMIC INSTABILITY BOTH DIRECTLY AND THROUGH EPIGENETIC PATHWAYS. OVERALL, THE MECHANISMS OF H. PYLORI-INDUCED HOST GENOMIC INSTABILITIES REMAIN POORLY UNDERSTOOD. WE USED MICROARRAY SCREENING OF H. PYLORI-INFECTED HUMAN GASTRIC BIOPSY SPECIMENS TO IDENTIFY CANDIDATE GENES INVOLVED IN H. PYLORI-INDUCED HOST GENOMIC INSTABILITIES. WE FOUND UPREGULATION OF ATM EXPRESSION IN VIVO IN GASTRIC MUCOSAL CELLS INFECTED WITH H. PYLORI. USING GASTRIC CANCER CELL LINES, WE CONFIRMED THAT THE H. PYLORI-RELATED ACTIVATION OF ATM WAS DUE TO THE ACCUMULATION OF DNA DOUBLE-STRAND BREAKS (DSBS). DSBS WERE OBSERVED FOLLOWING INFECTION WITH BOTH CAG PATHOGENICITY ISLAND (PAI)-POSITIVE AND -NEGATIVE STRAINS, BUT THE EFFECT WAS MORE ROBUST WITH CAG PAI-POSITIVE STRAINS. THESE RESULTS ARE CONSISTENT WITH THE FACT THAT INFECTIONS WITH BOTH CAG PAI-POSITIVE AND -NEGATIVE STRAINS ARE ASSOCIATED WITH GASTRIC CARCINOGENESIS, BUT THE RISK IS HIGHER IN INDIVIDUALS INFECTED WITH CAG PAI-POSITIVE STRAINS. 2014 18 4725 26 NORMAL GASTRIC TISSUE HELICOBACTER PYLORI INFECTION IS ASSOCIATED WITH EPIGENETIC AGE ACCELERATION, INCREASED MITOTIC TICK RATE, TISSUE CELL COMPOSITION, AND NATURAL KILLER CELL METHYLATION ALTERATIONS. BACKGROUND: GASTRIC ADENOCARCINOMAS ARE A LEADING CAUSE OF GLOBAL MORTALITY, ASSOCIATED WITH CHRONIC INFECTION WITH HELICOBACTER PYLORI . THE MECHANISMS BY WHICH INFECTION WITH H. PYLORI CONTRIBUTES TO CARCINOGENESIS ARE NOT WELL UNDERSTOOD. RECENT STUDIES FROM SUBJECTS WITH AND WITHOUT GASTRIC CANCER HAVE IDENTIFIED SIGNIFICANT DNA METHYLATION ALTERATIONS IN NORMAL GASTRIC MUCOSA ASSOCIATED WITH H. PYLORI INFECTION AND GASTRIC CANCER RISK. HERE WE FURTHER INVESTIGATED DNA METHYLATION ALTERATIONS IN NORMAL GASTRIC MUCOSA IN GASTRIC CANCER CASES (N = 42) AND CONTROL SUBJECTS (N = 42) WITH H. PYLORI INFECTION DATA. WE ASSESSED TISSUE CELL TYPE COMPOSITION, DNA METHYLATION ALTERATIONS WITHIN CELL POPULATIONS, EPIGENETIC AGING, AND REPETITIVE ELEMENT METHYLATION. RESULTS: IN NORMAL GASTRIC MUCOSA OF BOTH GASTRIC CANCER CASES AND CONTROL SUBJECTS, WE OBSERVED INCREASED EPIGENETIC AGE ACCELERATION ASSOCIATED WITH H. PYLORI INFECTION. WE ALSO OBSERVED AN INCREASED MITOTIC TICK RATE ASSOCIATED WITH H. PYLORI INFECTION IN BOTH GASTRIC CANCER CASES AND CONTROLS. SIGNIFICANT DIFFERENCES IN IMMUNE CELL POPULATIONS ASSOCIATED WITH H. PYLORI INFECTION IN NORMAL TISSUE FROM CANCER CASES AND CONTROLS WERE IDENTIFIED USING DNA METHYLATION CELL TYPE DECONVOLUTION. WE ALSO FOUND NATURAL KILLER CELL-SPECIFIC METHYLATION ALTERATIONS IN NORMAL MUCOSA FROM GASTRIC CANCER PATIENTS WITH H. PYLORI INFECTION. CONCLUSIONS: OUR FINDINGS FROM NORMAL GASTRIC MUCOSA PROVIDE INSIGHT INTO UNDERLYING CELLULAR COMPOSITION AND EPIGENETIC ASPECTS OF H. PYLORI ASSOCIATED GASTRIC CANCER ETIOLOGY. 2023 19 5767 26 SPECIES-SPECIFIC ROLE OF GENE-ADJACENT RETROELEMENTS IN HUMAN AND MOUSE GASTRIC CARCINOGENESIS. HELICOBACTER PYLORI (HP) INFECTION PROMOTES THE RECRUITMENT OF BONE MARROW STEM CELLS INTO CHRONIC GASTRITIS LESIONS. SOME OF THESE MARROW STEM CELLS CAN DIFFERENTIATE INTO GASTRIC EPITHELIAL CELLS AND NEOPLASTIC CELLS. WE PROPOSE THAT HP-ASSOCIATED METHYLATION COULD STABILIZE TRANS-DIFFERENTIATION OF MARROW-DERIVED STEM CELLS AND THAT AN UNSTABLE METHYLATION STATUS IS ASSOCIATED WITH A RISK OF GASTRIC CANCER. PATHOBIOLOGIC BEHAVIOR OF EXPERIMENTAL MOUSE GASTRIC CANCER IS MILD COMPARED TO INVASIVE AND METASTATIC HUMAN GASTRIC CANCER. DIFFERENCES IN EPIGENETIC STABILIZATION OF ADULT CELL PHENOTYPES BETWEEN HUMANS AND MICE COULD PROVIDE A FOUNDATION TO EXPLORE THE DEVELOPMENT OF INVASIVE AND METASTATIC GASTRIC CANCER. RETROELEMENTS ARE HIGHLY REPETITIVE SEQUENCES THAT PLAY AN ESSENTIAL ROLE IN THE GENERATION OF SPECIES DIVERSITY. IN THIS REVIEW, WE ANALYZED RETROELEMENTS ADJACENT TO HUMAN AND MOUSE HOUSEKEEPING GENES AND PROPOSED A POSSIBLE EPIGENETIC MECHANISM FOR HP-ASSOCIATED CARCINOGENESIS. 2018 20 3233 27 HELICOBACTER, INFLAMMATION, AND GASTRIC CANCER. HELICOBACTER PYLORI INFECTION LEADS TO LONG-LASTING CHRONIC INFLAMMATION AND REPRESENTS THE MOST COMMON RISK FACTOR UNDERLYING GASTRIC CANCER. RECENTLY, NEW INSIGHTS INTO THE MECHANISMS THROUGH WHICH H. PYLORI AND MUCOSAL INFLAMMATION LEAD TO CANCER DEVELOPMENT HAVE EMERGED. H. PYLORI VIRULENCE FACTORS, IN PARTICULAR SPECIFIC CAGA GENOTYPES, REPRESENT MAIN FACTORS IN GASTRIC CANCER, INDUCING ALTERED INTRACELLULAR SIGNALING IN EPITHELIAL CELLS. THE CHRONIC NATURE OF H. PYLORI INFECTION APPEARS TO RELATE TO THE VACA VIRULENCE FACTOR AND TH17/TREG MECHANISMS. A ROLE OF H. PYLORI INFECTION IN EPIGENETIC AND MICRORNA DEREGULATION HAS BEEN SHOWN. MUTATION OF THE EPITHELIAL CELL GENOME, A HALLMARK OF CANCER, WAS DEMONSTRATED TO ACCUMULATE IN H. PYLORI INFECTED STOMACH PARTLY DUE TO INADEQUATE DNA REPAIR. GASTRIC STEM CELLS WERE SHOWN TO BE TARGETS OF OXIDATIVE INJURY IN THE HELICOBACTER-INFLAMMATORY MILIEU. RECENT ADVANCES EMPHASIZING THE CONTRIBUTION OF BACTERIAL FACTORS, INFLAMMATORY MEDIATORS, AND THE HOST EPITHELIAL RESPONSE IN GASTRIC CARCINOGENESIS ARE REVIEWED. 2013