1 6663 121 UPREGULATION OF HISTONE-LYSINE METHYLTRANSFERASES PLAYS A CAUSAL ROLE IN HEXAVALENT CHROMIUM-INDUCED CANCER STEM CELL-LIKE PROPERTY AND CELL TRANSFORMATION. WHILE HEXAVALENT CHROMIUM [CR(VI)] IS GENERALLY CONSIDERED AS A GENOTOXIC ENVIRONMENTAL CARCINOGEN, STUDIES SHOWED THAT CR(VI) EXPOSURE ALSO CAUSES EPIGENETIC CHANGES. HOWEVER, WHETHER CR(VI)-CAUSED EPIGENETIC DYSREGULATIONS PLAYS AN IMPORTANT ROLE IN CR(VI) CARCINOGENICITY REMAIN LARGELY UNKNOWN. THE AIM OF THIS STUDY WAS TO DETERMINE IF CHRONIC LOW DOSE CR(VI) EXPOSURE CAUSES EPIGENETIC CHANGES, THE UNDERLYING MECHANISM AND WHETHER CHRONIC LOW DOSE CR(VI) EXPOSURE-CAUSED EPIGENETIC DYSREGULATION CONTRIBUTES CAUSALLY TO CR(VI)-INDUCED CANCER STEM CELL (CSC)-LIKE PROPERTY AND CELL TRANSFORMATION. TWO IMMORTALIZED HUMAN BRONCHIAL EPITHELIAL CELL LINES (BEAS-2B AND 16HBE) WERE EXPOSED TO 0.25 MUM OF K(2)CR(2)O(7) FOR 20 AND 40 WEEKS TO INDUCE CELL TRANSFORMATION, RESPECTIVELY. CR(VI)-INDUCED EPIGENETIC CHANGES WERE EXAMINED IN CR(VI)-TRANSFORMED CELLS AND CR(VI) EXPOSURE-CAUSED HUMAN LUNG CANCER TISSUES. PHARMACOLOGICAL INHIBITORS AND GENE KNOCKDOWN EXPERIMENTS WERE USED TO DETERMINE THE ROLE OF EPIGENETIC DYSREGULATION IN CR(VI) CARCINOGENICITY. WE FOUND THAT CHRONIC CR(VI) EXPOSURE CAUSES EPIGENETIC DYSREGULATION AS EVIDENCED BY THE INCREASED LEVELS OF HISTONE H3 REPRESSIVE METHYLATION MARKS (H3K9ME2 AND H3K27ME3) AND THE RELATED HISTONE-LYSING METHYLTRANSFERASES (HMTASES). PHARMACOLOGICAL INHIBITION OR KNOCKDOWN OF HMTASES REDUCES H3 REPRESSIVE METHYLATION MARKS AND MALIGNANT PHENOTYPES OF CR(VI)-TRANSFORMED CELLS. MOREOVER, KNOCKDOWN OF HMTASES IN PARENTAL CELLS SIGNIFICANTLY REDUCES CHRONIC CR(VI) EXPOSURE-INDUCED CSC-LIKE PROPERTY AND CELL TRANSFORMATION. FURTHER MECHANISTIC STUDY REVEALED THAT KNOCKDOWN OF HMTASES DECREASES CR(VI) EXPOSURE-CAUSED DNA DAMAGE. OUR FINDINGS INDICATE THAT CHRONIC CR(VI) EXPOSURE INCREASES H3 REPRESSIVE METHYLATION MARKS BY INCREASING THE RELATED HMTASES EXPRESSION; AND THAT INCREASED EXPRESSION OF HMTASES PLAYS A CAUSAL ROLE IN CR(VI)-INDUCED CSC-LIKE PROPERTY AND CELL TRANSFORMATION. 2018 2 1987 46 EPIGENETIC ALTERATIONS OF CXCL5 IN CR(VI)-INDUCED CARCINOGENESIS. CHRONIC EXPOSURE TO HEXAVALENT CHROMIUM COMPOUNDS [CR(VI)] IS ASSOCIATED WITH AN INCREASED RISK OF CANCERS, BUT THE MOLECULAR MECHANISMS REMAIN TO BE ELUCIDATED. IN THIS STUDY, WE FOUND THAT CXCL5 LEVELS IN PERIPHERAL BLOOD MONOCYTES (PBMCS) AND PLASMA FROM WORKERS WITH OCCUPATIONAL EXPOSURE TO CR(VI) WERE DRAMATICALLY UPREGULATED COMPARED TO NON-EXPOSURE HEALTHY SUBJECTS, AND PLASMA C-X-C MOTIF CHEMOKINE LIGAND 5 (CXCL5) CXCL5 LEVELS WERE POSITIVELY CORRELATED WITH CR CONCENTRATIONS IN SUBJECTS' TOENAILS. ZINC CHROMATE EXPOSED MICE SHOWED HIGHER LEVELS OF CXCL5 AND ITS RECEPTOR CXCR2 IN LUNG TISSUES, AND IN PBMCS. SIMILAR CXCL5 UPREGULATION WAS EVIDENT IN CR(VI)-INDUCED TRANSFORMED (CR-T) CELLS WITH LONG-TERM CR(VI) TREATMENT. MECHANISTIC STUDIES SHOWED THAT ELEVATED CXCL5 EXPRESSION LEVELS WERE REGULATED BY CR(VI)-INDUCED HISTONE MODIFICATIONS AND DNA HYPOMETHYLATION, AND THAT THE C-MYC/P300 COMPLEX WAS A KEY UPSTREAM REGULATOR OF HISTONE H3 ACETYLATION. CXCL5 OVEREXPRESSION PROMOTED CR(VI)-INDUCED THE EPITHELIAL TO MESENCHYME TRANSITION (EMT) BY UPREGULATING ZINC FINGER E-BOX BINDING HOMEOBOX 1 (ZEB1) TO PROMOTE TUMOR DEVELOPMENT. OUR FINDINGS IDENTIFY A NOVEL MECHANISM BY WHICH CXCL5 IS UPREGULATED AND PROMOTES EMT AND CARCINOGENESIS UPON CHRONIC CR(VI) EXPOSURE. OUR WORK ALSO IMPLIES THAT CXCL5 MRNA AND PROTEIN LEVELS WILL ELEVATE IN PBMCS AND SERUM AFTER OCCUPATIONAL CR(VI) EXPOSURE, WHICH MAY BE A POTENTIAL TARGET AND BIOMARKER FOR CANCER PREVENTION AND HEALTH SURVEILLANCE AMONG POPULATIONS EXPOSED TO CR(VI). 2022 3 1557 29 DNA METHYLATION MODIFICATIONS INDUCED BY HEXAVALENT CHROMIUM. HEXAVALENT CHROMIUM [CR (VI)] CONTRIBUTES A SIGNIFICANT HEALTH RISK AND CAUSES A NUMBER OF CHRONIC DISEASES AND CANCERS. WHILE THE GENOTOXIC AND CARCINOGENIC EFFECTS OF HEXAVALENT CHROMIUM EXPOSURE ARE EXPLICIT AND BETTER-CHARACTERIZED, THE EXACT MECHANISM UNDERLYING THE CARCINOGENIC PROCESS OF CR (VI) IS STILL A MATTER OF DEBATE. IN RECENT YEARS, STUDIES HAVE SHOWN THAT EPIGENETIC MODIFICATIONS, ESPECIALLY DNA METHYLATION, MAY PLAY A SIGNIFICANT ROLE IN CR (VI)-INDUCED CARCINOGENESIS. THE AIM OF THIS REVIEW IS TO SUMMARIZE OUR UNDERSTANDING REGARDING THE EFFECTS OF CR (VI) ON GLOBAL AND GENE-SPECIFIC DNA METHYLATION. 2019 4 1993 44 EPIGENETIC AND EPITRANSCRIPTOMIC MECHANISMS OF CHROMIUM CARCINOGENESIS. HEXAVALENT CHROMIUM [CR(VI)], A GROUP I CARCINOGEN CLASSIFIED BY THE INTERNATIONAL AGENCY FOR RESEARCH ON CANCER (IARC), REPRESENTS ONE OF THE MOST COMMON OCCUPATIONAL AND ENVIRONMENTAL POLLUTANTS. THE FINDINGS FROM HUMAN EPIDEMIOLOGICAL AND LABORATORY ANIMAL STUDIES SHOW THAT LONG-TERM EXPOSURE TO CR(VI) CAUSES LUNG CANCER AND OTHER CANCER. ALTHOUGH CR(VI) IS A WELL-RECOGNIZED CARCINOGEN, THE MECHANISM OF CR(VI) CARCINOGENESIS HAS NOT BEEN WELL UNDERSTOOD. DUE TO THE FACT THAT CR(VI) UNDERGOES A SERIES OF METABOLIC REDUCTIONS ONCE ENTERING CELLS TO GENERATE REACTIVE CR METABOLITES AND REACTIVE OXYGEN SPECIES (ROS) CAUSING GENOTOXICITY, CR(VI) IS GENERALLY CONSIDERED AS A GENOTOXIC CARCINOGEN. HOWEVER, MORE AND MORE STUDIES HAVE DEMONSTRATED THAT ACUTE OR CHRONIC CR(VI) EXPOSURE ALSO CAUSES EPIGENETIC DYSREGULATIONS INCLUDING CHANGING DNA METHYLATION, HISTONE POSTTRANSLATIONAL MODIFICATIONS AND REGULATORY NON-CODING RNA (MICRORNA AND LONG NON-CODING RNA) EXPRESSIONS. MOREOVER, EMERGING EVIDENCE SHOWS THAT CR(VI) EXPOSURE IS ALSO CAPABLE OF ALTERING CELLULAR EPITRANSCRIPTOME. GIVEN THE INCREASINGLY RECOGNIZED IMPORTANCE OF EPIGENETIC AND EPITRANSCRIPTOMIC DYSREGULATIONS IN CANCER INITIATION AND PROGRESSION, IT IS BELIEVED THAT CR(VI) EXPOSURE-CAUSED EPIGENETIC AND EPITRANSCRIPTOMIC CHANGES COULD PLAY IMPORTANT ROLES IN CR(VI) CARCINOGENESIS. THE GOAL OF THIS CHAPTER IS TO REVIEW THE EPIGENETIC AND EPITRANSCRIPTOMIC EFFECTS OF CR(VI) EXPOSURE AND DISCUSS THEIR ROLES IN CR(VI) CARCINOGENESIS. BETTER UNDERSTANDING THE MECHANISM OF CR(VI) CARCINOGENESIS MAY IDENTIFY NEW MOLECULAR TARGETS FOR MORE EFFICIENT PREVENTION AND TREATMENT OF CANCER RESULTING FROM CR(VI) EXPOSURE. 2023 5 1122 50 COMPARISON OF GENE EXPRESSION PROFILES IN CHROMATE TRANSFORMED BEAS-2B CELLS. BACKGROUND: HEXAVALENT CHROMIUM [CR(VI)] IS A POTENT HUMAN CARCINOGEN. OCCUPATIONAL EXPOSURE HAS BEEN ASSOCIATED WITH INCREASED RISK OF RESPIRATORY CANCER. MULTIPLE MECHANISMS HAVE BEEN SHOWN TO CONTRIBUTE TO CR(VI) INDUCED CARCINOGENESIS, INCLUDING DNA DAMAGE, GENOMIC INSTABILITY, AND EPIGENETIC MODULATION, HOWEVER, THE MOLECULAR MECHANISM AND DOWNSTREAM GENES MEDIATING CHROMIUM'S CARCINOGENICITY REMAIN TO BE ELUCIDATED. METHODS/RESULTS: WE ESTABLISHED CHROMATE TRANSFORMED CELL LINES BY CHRONIC EXPOSURE OF NORMAL HUMAN BRONCHIAL EPITHELIAL BEAS-2B CELLS TO LOW DOSES OF CR(VI) FOLLOWED BY ANCHORAGE-INDEPENDENT GROWTH. THESE TRANSFORMED CELL LINES NOT ONLY EXHIBITED CONSISTENT MORPHOLOGICAL CHANGES BUT ALSO ACQUIRED ALTERED AND DISTINCT GENE EXPRESSION PATTERNS COMPARED WITH NORMAL BEAS-2B CELLS AND CONTROL CELL LINES (UNTREATED) THAT AROSE SPONTANEOUSLY IN SOFT AGAR. INTERESTINGLY, THE GENE EXPRESSION PROFILES OF SIX CR(VI) TRANSFORMED CELL LINES WERE REMARKABLY SIMILAR TO EACH OTHER YET DIFFERED SIGNIFICANTLY FROM THAT OF EITHER CONTROL CELL LINES OR NORMAL BEAS-2B CELLS. A TOTAL OF 409 DIFFERENTIALLY EXPRESSED GENES WERE IDENTIFIED IN CR(VI) TRANSFORMED CELLS COMPARED TO CONTROL CELLS. GENES RELATED TO CELL-TO-CELL JUNCTION WERE UPREGULATED IN ALL CR(VI) TRANSFORMED CELLS, WHILE GENES ASSOCIATED WITH THE INTERACTION BETWEEN CELLS AND THEIR EXTRACELLULAR MATRICES WERE DOWN-REGULATED. ADDITIONALLY, EXPRESSION OF GENES INVOLVED IN CELL PROLIFERATION AND APOPTOSIS WERE ALSO CHANGED. CONCLUSION: THIS STUDY IS THE FIRST TO REPORT GENE EXPRESSION PROFILING OF CR(VI) TRANSFORMED CELLS. THE GENE EXPRESSION CHANGES ACROSS INDIVIDUAL CHROMATE EXPOSED CLONES WERE REMARKABLY SIMILAR TO EACH OTHER BUT DIFFERED SIGNIFICANTLY FROM THE GENE EXPRESSION FOUND IN ANCHORAGE-INDEPENDENT CLONES THAT AROSE SPONTANEOUSLY. OUR ANALYSIS IDENTIFIED MANY NOVEL GENE EXPRESSION CHANGES THAT MAY CONTRIBUTE TO CHROMATE INDUCED CELL TRANSFORMATION, AND COLLECTIVELY THIS TYPE OF INFORMATION WILL PROVIDE A BETTER UNDERSTANDING OF THE MECHANISM UNDERLYING CHROMATE CARCINOGENICITY. 2011 6 4208 38 METAL CARCINOGEN EXPOSURE INDUCES CANCER STEM CELL-LIKE PROPERTY THROUGH EPIGENETIC REPROGRAMING: A NOVEL MECHANISM OF METAL CARCINOGENESIS. ARSENIC, CADMIUM, NICKEL AND HEXAVALENT CHROMIUM ARE AMONG THE MOST COMMON ENVIRONMENTAL POLLUTANTS AND POTENT CARCINOGENS. CHRONIC EXPOSURE TO THESE METALS CAUSES VARIOUS TYPES OF CANCER IN HUMANS, REPRESENTING A SIGNIFICANT ENVIRONMENTAL HEALTH ISSUE. ALTHOUGH UNDER ACTIVE INVESTIGATION, THE MECHANISMS OF METAL CARCINOGENESIS HAVE NOT BEEN CLEARLY DEFINED. ONE COMMON FEATURE OF THESE METAL CARCINOGENS IS THAT THEY ARE ALL ABLE TO CAUSE VARIOUS EPIGENETIC DYSREGULATIONS, WHICH ARE BELIEVED TO PLAY IMPORTANT ROLES IN THEIR CARCINOGENICITY. HOWEVER, HOW METAL CARCINOGEN-CAUSED EPIGENETIC DYSREGULATION CONTRIBUTES TO METAL CARCINOGENESIS REMAINS LARGELY UNKNOWN. THE EVOLUTION OF CANCER STEM CELL (CSC) THEORY HAS OPENED EXCITING NEW AVENUES FOR STUDYING THE MECHANISM OF METAL CARCINOGENESIS. INCREASING EVIDENCE INDICATES THAT CHRONIC METAL CARCINOGEN EXPOSURE PRODUCES CSC-LIKE CELLS THROUGH DYSREGULATED EPIGENETIC MECHANISMS. THIS REVIEW WILL FIRST PROVIDE SOME BRIEF INTRODUCTIONS ABOUT CSC, EPIGENETICS AND EPIGENETIC REGULATION OF CSCS; THEN SUMMARIZE PROGRESSES IN RECENT STUDIES ON METAL CARCINOGEN-INDUCED CSC-LIKE PROPERTY THROUGH EPIGENETIC REPROGRAMING AS A NOVEL MECHANISM OF METAL CARCINOGENESIS. SOME PERSPECTIVES FOR FUTURE STUDIES IN THIS FIELD ARE ALSO PRESENTED. 2019 7 3942 52 LNCRNA DUXAP10 UPREGULATION AND THE HEDGEHOG PATHWAY ACTIVATION ARE CRITICALLY INVOLVED IN CHRONIC CADMIUM EXPOSURE-INDUCED CANCER STEM CELL-LIKE PROPERTY. CADMIUM (CD) IS A WELL-KNOWN LUNG CARCINOGEN. HOWEVER, THE MECHANISM OF CD CARCINOGENESIS REMAINS TO BE CLEARLY DEFINED. CD HAS BEEN SHOWN TO ACT AS A WEAK MUTAGEN, SUGGESTING THAT IT MAY EXERT TUMORIGENIC EFFECT THROUGH NONGENOTOXIC WAYS, SUCH AS EPIGENETIC MECHANISMS. LONG NONCODING RNAS (LNCRNAS) REFER TO RNA MOLECULES THAT ARE LONGER THAN 200 NUCLEOTIDES IN LENGTH BUT LACK PROTEIN-CODING CAPACITIES. REGULATION OF GENE EXPRESSIONS BY LNCRNAS IS CONSIDERED AS ONE OF IMPORTANT EPIGENETIC MECHANISMS. THE GOAL OF THIS STUDY IS TO INVESTIGATE THE MECHANISM OF CD CARCINOGENESIS FOCUSING ON THE ROLE OF LNCRNA DYSREGULATIONS. CD-INDUCED MALIGNANT TRANSFORMATION OF HUMAN BRONCHIAL EPITHELIA BEAS-2B CELLS WAS ACCOMPLISHED BY A 9-MONTH LOW-DOSE CD (CDCL2, 2.5 MICROM) EXPOSURE. THE CD-EXPOSED CELLS FORMED SIGNIFICANTLY MORE COLONIES IN SOFT AGAR, DISPLAYED CANCER STEM CELL (CSC)-LIKE PROPERTY, AND FORMED TUMORS IN NUDE MICE. MECHANISTICALLY, CHRONIC LOW-DOSE CD EXPOSURE DID NOT CAUSE SIGNIFICANT GENOTOXIC EFFECTS BUT DYSREGULATED LNCRNA EXPRESSIONS. FURTHER Q-PCR ANALYSIS CONFIRMED THE SIGNIFICANT UPREGULATION OF THE ONCOGENIC LNCRNA DUXAP10 IN CD-TRANSFORMED CELLS. DUXAP10 KNOCKDOWN IN CD-TRANSFORMED CELLS SIGNIFICANTLY REDUCED THEIR CSC-LIKE PROPERTY. FURTHER MECHANISTIC STUDIES SHOWED THAT THE HEDGEHOG PATHWAY IS ACTIVATED IN CD-TRANSFORMED CELLS AND INHIBITION OF THIS PATHWAY REDUCES CD-INDUCED CSC-LIKE PROPERTY. DUXAP10 KNOCKDOWN CAUSED THE HEDGEHOG PATHWAY INACTIVATION IN CD-TRANSFORMED CELLS. FURTHERMORE, PAX6 EXPRESSION WAS UPREGULATED IN CD-TRANSFORMED CELLS AND PAX6 KNOCKDOWN SIGNIFICANTLY REDUCED THEIR DUXAP10 LEVELS AND CSC-LIKE PROPERTY. IN SUMMARY, THESE FINDINGS SUGGEST THAT THE LNCRNA DUXAP10 UPREGULATION MAY PLAY AN IMPORTANT ROLE IN CD CARCINOGENESIS. 2021 8 6370 31 THE ROLE OF MICRORNAS IN METAL CARCINOGEN-INDUCED CELL MALIGNANT TRANSFORMATION AND TUMORIGENESIS. MICRORNAS (MIRNAS), AN IMPORTANT COMPONENT OF EPIGENETIC MECHANISMS OF CARCINOGENESIS, HAVE BEEN SHOWN TO PLAY CRUCIAL ROLES IN CANCER INITIATION, METASTASIS, PROGNOSIS AND RESPONSES TO DRUG TREATMENT AND MAY SERVE AS BIOMARKERS FOR EARLY DIAGNOSIS OF CANCER AND TOOLS FOR CANCER THERAPY. METAL CARCINOGENS, SUCH AS ARSENIC, CADMIUM, HEXAVALENT CHROMIUM AND NICKEL, ARE WELL-ESTABLISHED HUMAN CARCINOGENS CAUSING VARIOUS CANCERS UPON LONG TERM EXPOSURE. HOWEVER, THE MECHANISM OF METAL CARCINOGENESIS HAS NOT BEEN WELL UNDERSTOOD, WHICH LIMITS OUR CAPABILITY TO EFFECTIVELY DIAGNOSE AND TREAT HUMAN CANCERS RESULTING FROM CHRONIC METAL CARCINOGEN EXPOSURE. OVER RECENT YEARS, THE ROLE OF MIRNAS IN METAL CARCINOGENESIS HAS BEEN ACTIVELY EXPLORED AND A GROWING BODY OF EVIDENCE INDICATES THE CRITICAL INVOLVEMENT OF MIRNAS IN METAL CARCINOGENESIS. THIS REVIEW AIMS TO DISCUSS RECENT STUDIES SHOWING THAT MIRNAS PLAY IMPORTANT ROLES IN METAL CARCINOGEN-INDUCED CELL MALIGNANT TRANSFORMATION AND TUMORIGENESIS. SOME THOUGHTS FOR FUTURE FURTHER STUDIES IN THIS FIELD ARE ALSO PRESENTED. 2016 9 481 43 ARSENIC-INDUCED SUMOYLATION OF MUS81 IS INVOLVED IN REGULATING GENOMIC STABILITY. CHRONIC ENVIRONMENTAL EXPOSURE TO METAL TOXICANTS SUCH AS CHROMIUM AND ARSENIC IS CLOSELY RELATED TO THE DEVELOPMENT OF SEVERAL TYPES OF COMMON CANCERS. GENETIC AND EPIGENETIC STUDIES IN THE PAST DECADE REVEAL THAT POST-TRANSLATIONAL MODIFICATIONS OF HISTONES PLAY A ROLE IN METAL CARCINOGENESIS. HOWEVER, EXACT MOLECULAR MECHANISMS OF METAL CARCINOGENESIS REMAIN TO BE ELUCIDATED. IN THIS STUDY WE FOUND THAT AS(2)O(3), AN ENVIRONMENTAL METAL TOXICANT, UPREGULATED OVERALL MODIFICATIONS OF MANY CELLULAR PROTEINS BY SUMO2/3. SUMOYLATED PROTEINS FROM ARSENIC-TREATED CELLS CONSTITUTIVELY EXPRESSING HIS(6)-SUMO2 WERE PULLED DOWN BY NI-IDA RESIN UNDER DENATURING CONDITIONS. MASS SPECTROMETRIC ANALYSIS REVEALED OVER 100 PROTEINS THAT WERE POTENTIALLY MODIFIED BY SUMOYLATION. MUS81, A DNA ENDONUCLEASE INVOLVED IN HOMOLOGOUS RECOMBINATION REPAIR, WAS AMONG THE IDENTIFIED PROTEINS WHOSE SUMOYLATION WAS INCREASED AFTER TREATMENT WITH AS(2)O(3.) WE FURTHER SHOWED THAT K10 AND K524 WERE 2 LYSINE RESIDUES ESSENTIAL FOR MUS81 SUMOYLATION. MOREOVER, WE DEMONSTRATED THAT MUS81 SUMOYLATION IS IMPORTANT FOR NORMAL MITOTIC CHROMOSOME CONGRESSION AND THAT CELLS EXPRESSING SUMO-RESISTANT MUS81 MUTANTS DISPLAYED COMPROMISED DNA DAMAGE RESPONSES AFTER EXPOSURE TO METAL TOXINS SUCH AS CR(VI) AND ARSENIC. 2017 10 1925 30 ENVIRONMENTAL EPIGENETICS IN METAL EXPOSURE. ALTHOUGH IT IS WIDELY ACCEPTED THAT CHRONIC EXPOSURE TO ARSENITE, NICKEL, CHROMIUM AND CADMIUM INCREASES CANCER INCIDENCE IN INDIVIDUALS, THE MOLECULAR MECHANISMS UNDERLYING THEIR ABILITY TO TRANSFORM CELLS REMAIN LARGELY UNKNOWN. CARCINOGENIC METALS ARE TYPICALLY WEAK MUTAGENS, SUGGESTING THAT GENETIC-BASED MECHANISMS MAY NOT BE PRIMARILY RESPONSIBLE FOR METAL-INDUCED CARCINOGENESIS. GROWING EVIDENCE SHOWS THAT ENVIRONMENTAL METAL EXPOSURE INVOLVES CHANGES IN EPIGENETIC MARKS, WHICH MAY LEAD TO A POSSIBLE LINK BETWEEN HERITABLE CHANGES IN GENE EXPRESSION AND DISEASE SUSCEPTIBILITY AND DEVELOPMENT. HERE, WE REVIEW RECENT ADVANCES IN THE UNDERSTANDING OF METAL EXPOSURE AFFECTING EPIGENETIC MARKS AND DISCUSS ESTABLISHMENT OF HERITABLE GENE EXPRESSION IN METAL-INDUCED CARCINOGENESIS. 2011 11 2961 38 GENETIC AND EPIGENETIC MECHANISMS IN METAL CARCINOGENESIS AND COCARCINOGENESIS: NICKEL, ARSENIC, AND CHROMIUM. CHRONIC EXPOSURE TO NICKEL(II), CHROMIUM(VI), OR INORGANIC ARSENIC (IAS) HAS LONG BEEN KNOWN TO INCREASE CANCER INCIDENCE AMONG AFFECTED INDIVIDUALS. RECENT EPIDEMIOLOGICAL STUDIES HAVE FOUND THAT CARCINOGENIC RISKS ASSOCIATED WITH CHROMATE AND IAS EXPOSURES WERE SUBSTANTIALLY HIGHER THAN PREVIOUSLY THOUGHT, WHICH LED TO MAJOR REVISIONS OF THE FEDERAL STANDARDS REGULATING AMBIENT AND DRINKING WATER LEVELS. GENOTOXIC EFFECTS OF CR(VI) AND IAS ARE STRONGLY INFLUENCED BY THEIR INTRACELLULAR METABOLISM, WHICH CREATES SEVERAL REACTIVE INTERMEDIATES AND BYPRODUCTS. TOXIC METALS ARE CAPABLE OF POTENT AND SURPRISINGLY SELECTIVE ACTIVATION OF STRESS-SIGNALING PATHWAYS, WHICH ARE KNOWN TO CONTRIBUTE TO THE DEVELOPMENT OF HUMAN CANCERS. DEPENDING ON THE METAL, ASCORBATE (VITAMIN C) HAS BEEN FOUND TO ACT EITHER AS A STRONG ENHANCER OR SUPPRESSOR OF TOXIC RESPONSES IN HUMAN CELLS. IN ADDITION TO GENETIC DAMAGE VIA BOTH OXIDATIVE AND NONOXIDATIVE (DNA ADDUCTS) MECHANISMS, METALS CAN ALSO CAUSE SIGNIFICANT CHANGES IN DNA METHYLATION AND HISTONE MODIFICATIONS, LEADING TO EPIGENETIC SILENCING OR REACTIVATION OF GENE EXPRESSION. IN VITRO GENOTOXICITY EXPERIMENTS AND RECENT ANIMAL CARCINOGENICITY STUDIES PROVIDED STRONG SUPPORT FOR THE IDEA THAT METALS CAN ACT AS COCARCINOGENS IN COMBINATION WITH NONMETAL CARCINOGENS. COCARCINOGENIC AND COMUTAGENIC EFFECTS OF METALS ARE LIKELY TO STEM FROM THEIR ABILITY TO INTERFERE WITH DNA REPAIR PROCESSES. OVERALL, METAL CARCINOGENESIS APPEARS TO REQUIRE THE FORMATION OF SPECIFIC METAL COMPLEXES, CHROMOSOMAL DAMAGE, AND ACTIVATION OF SIGNAL TRANSDUCTION PATHWAYS PROMOTING SURVIVAL AND EXPANSION OF GENETICALLY/EPIGENETICALLY ALTERED CELLS. 2008 12 3842 28 IRON- AND 2-OXOGLUTARATE-DEPENDENT DIOXYGENASES: AN EMERGING GROUP OF MOLECULAR TARGETS FOR NICKEL TOXICITY AND CARCINOGENICITY. NICKEL COMPOUNDS ARE IMPORTANT OCCUPATIONAL AND ENVIRONMENTAL POLLUTANTS. CHRONIC EXPOSURE TO THESE POLLUTANTS HAS BEEN CONNECTED WITH INCREASED RISKS OF RESPIRATORY CANCERS AND CARDIOVASCULAR DISEASES. HOWEVER, IT IS STILL NOT CLEAR WHAT ARE THE SPECIFIC MOLECULAR TARGETS FOR NICKEL TOXICITY AND CARCINOGENICITY. HERE, WE PROPOSE THAT THE IRON- AND 2-OXOGLUTARATE-DEPENDENT DIOXYGENASE FAMILY ENZYMES ARE IMPORTANT INTRACELLULAR TARGETS THAT MEDIATE THE TOXICITY AND CARCINOGENICITY OF NICKEL. IN SUPPORT OF THIS HYPOTHESIS, OUR DATA SHOW THAT THREE DIFFERENT CLASSES OF ENZYMES IN THIS IRON- AND 2-OXOGLUTARATE-DEPENDENT DIOXYGENASE FAMILY, INCLUDING HIF-PROLYL HYDROXYLASE PHD2, HISTONE DEMETHYLASE JHDM2A/JMJD1A, AND DNA REPAIR ENZYME ABH3, ARE ALL HIGHLY SENSITIVE TO NICKEL INHIBITION. INACTIVATION OF THESE ENZYMES ACCOUNTS FOR A NUMBER OF DELETERIOUS EFFECTS CAUSED BY NICKEL IN CELLS, NAMELY HYPOXIA-MIMIC STRESS AND ABERRANT EPIGENETIC CHANGES. FUTURE STUDIES ON NICKEL'S EFFECTS ON THESE IRON- AND 2-OXOGLUTARATE-DEPENDENT DIOXYGENASES WOULD DEEPEN OUR UNDERSTANDING ON NICKEL TOXICITY AND CARCINOGENICITY. 2009 13 323 39 ALKBH4 STABILIZATION IS REQUIRED FOR ARSENIC-INDUCED 6MA DNA METHYLATION INHIBITION, KERATINOCYTE MALIGNANT TRANSFORMATION, AND TUMORIGENICITY. INORGANIC ARSENIC IS ONE OF THE WELL-KNOWN HUMAN SKIN CARCINOGENS. HOWEVER, THE MOLECULAR MECHANISM BY WHICH ARSENIC PROMOTES CARCINOGENESIS REMAINS UNCLEAR. PREVIOUS STUDIES HAVE ESTABLISHED THAT EPIGENETIC CHANGES, INCLUDING CHANGES IN DNA METHYLATION, ARE AMONG THE CRITICAL MECHANISMS THAT DRIVE CARCINOGENESIS. N(6)-METHYLADENINE (6MA) METHYLATION ON DNA IS A WIDESPREAD EPIGENETIC MODIFICATION THAT WAS INITIALLY FOUND ON BACTERIAL AND PHAGE DNA. ONLY RECENTLY HAS 6MA BEEN IDENTIFIED IN MAMMALIAN GENOMES. HOWEVER, THE FUNCTION OF 6MA IN GENE EXPRESSION AND CANCER DEVELOPMENT IS NOT WELL UNDERSTOOD. HERE, WE SHOW THAT CHRONIC LOW DOSES OF ARSENIC INDUCE MALIGNANT TRANSFORMATION AND TUMORIGENESIS IN KERATINOCYTES AND LEAD TO THE UPREGULATION OF ALKBH4 AND DOWNREGULATION OF 6MA ON DNA. WE FOUND THAT REDUCED 6MA LEVELS IN RESPONSE TO LOW LEVELS OF ARSENIC WERE MEDIATED BY THE UPREGULATION OF THE 6MA DNA DEMETHYLASE ALKBH4. MOREOVER, WE FOUND THAT ARSENIC INCREASED ALKBH4 PROTEIN LEVELS AND THAT ALKBH4 DELETION IMPAIRED ARSENIC-INDUCED TUMORIGENICITY IN VITRO AND IN MICE. MECHANISTICALLY, WE FOUND THAT ARSENIC PROMOTED ALKBH4 PROTEIN STABILITY THROUGH REDUCED AUTOPHAGY. TOGETHER, OUR FINDINGS REVEAL THAT THE DNA 6MA DEMETHYLASEALKBH4 PROMOTES ARSENIC TUMORIGENICITY AND ESTABLISHES ALKBH4 AS A PROMISING TARGET FOR ARSENIC-INDUCED TUMORIGENESIS. 2022 14 192 41 ACETYLATED H4K16 BY MYST1 PROTECTS UROTSA CELLS FROM ARSENIC TOXICITY AND IS DECREASED FOLLOWING CHRONIC ARSENIC EXPOSURE. ARSENIC, A HUMAN CARCINOGEN THAT IS ASSOCIATED WITH AN INCREASED RISK OF BLADDER CANCER, IS COMMONLY FOUND IN DRINKING WATER. AN IMPORTANT MECHANISM BY WHICH ARSENIC IS THOUGHT TO BE CARCINOGENIC IS THROUGH THE INDUCTION OF EPIGENETIC CHANGES THAT LEAD TO ABERRANT GENE EXPRESSION. PREVIOUSLY, WE REPORTED THAT THE SAS2 GENE IS REQUIRED FOR OPTIMAL GROWTH OF YEAST IN THE PRESENCE OF ARSENITE (AS(III)). YEAST SAS2P IS ORTHOLOGOUS TO HUMAN MYST1, A HISTONE 4 LYSINE 16 (H4K16) ACETYLTRANSFERASE. HERE, WE SHOW THAT H4K16 ACETYLATION IS NECESSARY FOR THE RESISTANCE OF YEAST TO AS(III) THROUGH THE MODULATION OF CHROMATIN STATE. WE FURTHER EXPLORED THE ROLE OF MYST1 AND H4K16 ACETYLATION IN ARSENIC TOXICITY AND CARCINOGENESIS IN HUMAN BLADDER EPITHELIAL CELLS. THE EXPRESSION OF MYST1 WAS KNOCKED DOWN IN UROTSA CELLS, A MODEL OF BLADDER EPITHELIUM THAT HAS BEEN USED TO STUDY ARSENIC-INDUCED CARCINOGENESIS. SILENCING OF MYST1 REDUCED ACETYLATION OF H4K16 AND INDUCED SENSITIVITY TO AS(III) AND TO ITS MORE TOXIC METABOLITE MONOMETHYLARSONOUS ACID (MMA(III)) AT DOSES RELEVANT TO HIGH ENVIRONMENTAL HUMAN EXPOSURES. IN ADDITION, BOTH AS(III) AND MMA(III) TREATMENTS DECREASED GLOBAL H4K16 ACETYLATION LEVELS IN A DOSE- AND TIME-DEPENDENT MANNER. THIS INDICATES THAT ACETYLATED H4K16 IS REQUIRED FOR RESISTANCE TO ARSENIC AND THAT A REDUCTION IN ITS LEVELS AS A CONSEQUENCE OF ARSENIC EXPOSURE MAY CONTRIBUTE TO TOXICITY IN UROTSA CELLS. BASED ON THESE FINDINGS, WE PROPOSE A NOVEL ROLE FOR THE MYST1 GENE IN HUMAN SENSITIVITY TO ARSENIC. 2009 15 3474 39 IDENTIFICATION OF A RICE METALLOCHAPERONE FOR CADMIUM TOLERANCE BY AN EPIGENETIC MECHANISM AND POTENTIAL USE FOR CLEAN UP IN WETLAND. CADMIUM (CD) IS A TOXIC HEAVY METAL THAT INITIATES DIVERSE CHRONIC DISEASES THROUGH FOOD CHAINS. DEVELOPING A BIOTECHNOLOGY FOR MANIPULATING CD UPTAKE IN PLANTS IS BENEFICIAL TO REDUCE ENVIRONMENTAL AND HEALTH RISKS. HERE, WE IDENTIFIED A NOVEL EPIGENETIC MECHANISM UNDERLYING CD ACCUMULATION REGULATED BY AN UNCHARACTERIZED METALLOCHAPERONE NAMELY HEAVY METAL RESPONSIVE PROTEIN (HMP) IN RICE PLANTS. OSHMP RESIDES IN CYTOPLASM AND NUCLEUS, DOMINANTLY INDUCED BY CD STRESS AND BINDS DIRECTLY TO CD IONS. OSHMP OVEREXPRESSION ENHANCED THE RICE GROWTH UNDER CD STRESS BUT ACCUMULATED MORE CD, WHEREAS KNOCKOUT OR KNOCKDOWN OF OSHMP SHOWED A CONTRASTING EFFECT. THE ENHANCED CD ACCUMULATION IN THE TRANSGENIC LINES WAS CONFIRMED BY A LONG-TERM EXPERIMENT WITH RICE GROWING AT THE ENVIRONMENTALLY REALISTIC CD CONCENTRATION IN SOIL. THE BISULFITE SEQUENCING AND CHROMATIN IMMUNOPRECIPITATION ASSESSMENTS REVEALED THAT CD STRESS REDUCED SIGNIFICANTLY THE DNA METHYLATION AT CPG (CYTOSINE-GUANINE) AND HISTONE H3K9ME2 MARKS IN THE UPSTREAM OF OSHMP. BY IDENTIFYING A COUPLE OF MUTANTS DEFECTIVE IN DNA METHYLATION AND HISTONE MODIFICATION (H3K9ME2) SUCH AS OSMET1 (METHYLATRANSFEASE1) AND OSSDG714 (KRYPTONITE), WE FOUND THAT THE CD-INDUCED EPIGENETIC HYPOMETHYLATION AT THE REGION WAS ASSOCIATED WITH OSHMP OVEREXPRESSION, WHICH CONSEQUENTLY LED TO CD DETOXIFICATION IN RICE. THE CAUSAL RELATIONSHIP WAS CONFIRMED BY THE GUS REPORTER GENE COUPLED WITH OSHMP AND OSMET1 WHEREBY OSMET1 REPRESSED DIRECTLY THE OSHMP EXPRESSION. OUR WORK SIGNIFIES THAT EXPRESSION OF OSHMP IS REQUIRED FOR CD DETOXIFICATION IN RICE PLANTS, AND THE CD-INDUCED HYPOMETHYLATION IN THE SPECIFIC REGION IS RESPONSIBLE FOR THE ENHANCED OSHMP EXPRESSION. IN SUMMARY, THIS STUDY GAINED AN INSIGHT INTO THE EPIGENETIC MECHANISM FOR ADDITIONAL OSHMP EXPRESSION WHICH CONSEQUENTLY ENSURES RICE ADAPTATION TO THE CD-CONTAMINATED ENVIRONMENT. 2021 16 4155 24 MECHANISTIC UNDERSTANDING OF THE TOXIC EFFECTS OF ARSENIC AND WARFARE ARSENICALS ON HUMAN HEALTH AND ENVIRONMENT. WORLDWIDE, MORE THAN 200 MILLION PEOPLE ARE ESTIMATED TO BE EXPOSED TO UNSAFE LEVELS OF ARSENIC. CHRONIC EXPOSURE TO UNSAFE LEVELS OF GROUNDWATER ARSENIC IS RESPONSIBLE FOR MULTIPLE HUMAN DISORDERS, INCLUDING DERMAL, CARDIOVASCULAR, NEUROLOGICAL, PULMONARY, RENAL, AND METABOLIC CONDITIONS. CONSUMPTION OF RICE AND SEAFOOD (WHERE HIGH LEVELS OF ARSENIC ARE ACCUMULATED) IS ALSO RESPONSIBLE FOR HUMAN EXPOSURE TO ARSENIC. THE TOXICITY OF ARSENIC COMPOUNDS VARIES GREATLY AND MAY DEPEND ON THEIR CHEMICAL FORM, SOLUBILITY, AND CONCENTRATION. SURPRISINGLY, SYNTHETIC ORGANOARSENICALS ARE EXTREMELY TOXIC MOLECULES WHICH CREATED INTEREST IN THEIR DEVELOPMENT AS CHEMICAL WARFARE AGENTS (CWAS) DURING WORLD WAR I (WWI). AMONG THESE CWAS, ADAMSITE, CLARK I, CLARK II, AND LEWISITE ARE OF CRITICAL IMPORTANCE, AS STOCKPILES OF THESE AGENTS STILL EXIST WORLDWIDE. IN ADDITION, UNUSED WWII WEAPONIZED ARSENICALS DISCARDED IN WATER BODIES OR BURIED IN MANY PARTS OF THE WORLD CONTINUE TO POSE A SERIOUS THREAT TO THE ENVIRONMENT AND HUMAN HEALTH. METABOLIC INHIBITION, OXIDATIVE STRESS, GENOTOXICITY, AND EPIGENETIC ALTERATIONS INCLUDING MICRO-RNA-DEPENDENT REGULATION ARE SOME OF THE UNDERLYING MECHANISMS OF ARSENIC TOXICITY. MECHANISTIC UNDERSTANDING OF THE TOXICITY OF ORGANOARSENICALS IS ALSO CRITICAL FOR THE DEVELOPMENT OF EFFECTIVE THERAPEUTIC INTERVENTIONS. THIS REVIEW PROVIDES COMPREHENSIVE DETAILS AND A CRITICAL ASSESSMENT OF RECENTLY PUBLISHED DATA ON VARIOUS CHEMICAL FORMS OF ARSENIC, THEIR EXPOSURE, AND IMPLICATIONS ON HUMAN AND ENVIRONMENTAL HEALTH. 2023 17 1470 37 DISTINCT GENE EXPRESSION PROFILES IN IMMORTALIZED HUMAN UROTHELIAL CELLS EXPOSED TO INORGANIC ARSENITE AND ITS METHYLATED TRIVALENT METABOLITES. INORGANIC ARSENIC IS AN ENVIRONMENTAL CARCINOGEN. THE GENERATION OF TOXIC TRIVALENT METHYLATED METABOLITES COMPLICATES THE STUDY OF ARSENIC-MEDIATED CARCINOGENESIS. THIS STUDY SYSTEMATICALLY EVALUATED THE EFFECT OF CHRONIC TREATMENT WITH SODIUM ARSENITE (IAS(III)), MONOMETHYLARSONOUS ACID (MMA(III)), AND DIMETHYLARSINOUS ACID (DMA(III)) ON IMMORTALIZED HUMAN UROEPITHELIAL CELLS (SV-HUC-1 CELLS) USING CDNA MICROARRAY. AFTER EXPOSURE FOR 25 PASSAGES TO IAS(III) (0.5 MICROM), MMA(III) (0.05, 0.1, OR 0.2 MICROM), OR DMA(III) (0.2 OR 0.5 MICROM), SIGNIFICANT COMPOUND-SPECIFIC MORPHOLOGIC CHANGES WERE OBSERVED. A SET OF 114 GENES (5.7% OF THE EXAMINED GENES) WAS DIFFERENTIALLY EXPRESSED IN ONE OR MORE SETS OF ARSENICAL-TREATED CELLS COMPARED WITH UNTREATED CONTROLS. EXPRESSION ANALYSIS SHOWED THAT EXPOSURE OF CELLS TO DMA(III) RESULTED IN A GENE PROFILE DIFFERENT FROM THAT IN CELLS EXPOSED TO IAS(III) OR MMA(III), AND THAT THE IAS(III)-INDUCED GENE PROFILE WAS CLOSEST TO THAT IN THE TUMORIGENIC HUC-1-DERIVED 3-METHYLCHOLANTHRENE-INDUCED TUMORIGENIC CELL LINE MC-SV-HUC T2, WHICH WAS DERIVED FROM SV-HUC-1 CELLS BY METHYLCHOLANTHRENE TREATMENT. OF THE GENES AFFECTED BY ALL THREE ARSENICALS, ONLY ONE, THAT CODING FOR INTERLEUKIN-1 RECEPTOR, TYPE II, SHOWED ENHANCED EXPRESSION, A FINDING CONFIRMED BY THE REDUCED INCREASE IN NF-KAPPAB (NUCLEAR FACTOR KAPPA B) ACTIVITY SEEN IN RESPONSE TO INTERLEUKIN-1BETA IN IAS(III)-EXPOSED CELLS. THE EXPRESSION OF 11 GENES WAS SUPPRESSED BY ALL THREE ARSENICALS. 5-AZA-DEOXYCYTIDINE PARTIALLY RESTORED THE TRANSCRIPTION OF SEVERAL SUPPRESSED GENES, SHOWING THAT EPIGENETIC DNA METHYLATION WAS PROBABLY INVOLVED IN ARSENICAL-INDUCED GENE REPRESSION. OUR DATA DEMONSTRATE THAT CHRONIC EXPOSURE TO IAS(III), MMA(III), OR DMA(III) HAS DIFFERENT EPIGENETIC EFFECTS ON UROTHELIAL CELLS AND REPRESSES NF-KAPPAB ACTIVITY. 2006 18 714 30 CADMIUM IS A MUTAGEN THAT ACTS BY INHIBITING MISMATCH REPAIR. MOST ERRORS THAT ARISE DURING DNA REPLICATION CAN BE CORRECTED BY DNA POLYMERASE PROOFREADING OR BY POST-REPLICATION MISMATCH REPAIR (MMR). INACTIVATION OF BOTH MUTATION-AVOIDANCE SYSTEMS RESULTS IN EXTREMELY HIGH MUTABILITY THAT CAN LEAD TO ERROR CATASTROPHE. HIGH MUTABILITY AND THE LIKELIHOOD OF CANCER CAN BE CAUSED BY MUTATIONS AND EPIGENETIC CHANGES THAT REDUCE MMR. HYPERMUTABILITY CAN ALSO BE CAUSED BY EXTERNAL FACTORS THAT DIRECTLY INHIBIT MMR. IDENTIFYING SUCH FACTORS HAS IMPORTANT IMPLICATIONS FOR UNDERSTANDING THE ROLE OF THE ENVIRONMENT IN GENOME STABILITY. WE FOUND THAT CHRONIC EXPOSURE OF YEAST TO ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF CADMIUM, A KNOWN HUMAN CARCINOGEN, CAN RESULT IN EXTREME HYPERMUTABILITY. THE MUTATION SPECIFICITY ALONG WITH RESPONSES IN PROOFREADING-DEFICIENT AND MMR-DEFICIENT MUTANTS INDICATE THAT CADMIUM REDUCES THE CAPACITY FOR MMR OF SMALL MISALIGNMENTS AND BASE-BASE MISMATCHES. IN EXTRACTS OF HUMAN CELLS, CADMIUM INHIBITED AT LEAST ONE STEP LEADING TO MISMATCH REMOVAL. TOGETHER, OUR DATA SHOW THAT A HIGH LEVEL OF GENETIC INSTABILITY CAN RESULT FROM ENVIRONMENTAL IMPEDIMENT OF A MUTATION-AVOIDANCE SYSTEM. 2003 19 3805 32 INTESTINE-SPECIFIC HOMEOBOX (ISX) INDUCES INTESTINAL METAPLASIA AND CELL PROLIFERATION TO CONTRIBUTE TO GASTRIC CARCINOGENESIS. BACKGROUND: HELICOBACTER PYLORI INDUCES CHRONIC INFLAMMATION AND INTESTINAL METAPLASIA (IM) THROUGH GENETIC AND EPIGENETIC CHANGES AND ACTIVATION OF INTRACELLULAR SIGNALING PATHWAYS THAT CONTRIBUTE TO GASTRIC CARCINOGENESIS. HOWEVER, THE PRECISE MECHANISM OF IM IN GASTRIC CARCINOGENESIS HAS NOT BEEN FULLY ELUCIDATED. WE PREVIOUSLY FOUND THAT INTESTINE-SPECIFIC HOMEOBOX (ISX) MRNA EXPRESSION INCREASED IN ORGANOIDS CULTURED FROM HELICOBACTER-INFECTED MOUSE MUCOSA. IN THIS STUDY, WE ELUCIDATE THE ROLE OF ISX IN THE DEVELOPMENT OF IM AND GASTRIC CARCINOGENESIS. METHODS: ISX EXPRESSION WAS ASSESSED IN HELICOBACTER-INFECTED MOUSE AND HUMAN GASTRIC MUCOSA. MKN45 GASTRIC CANCER CELLS WERE CO-CULTURED WITH H. PYLORI TO DETERMINE WHETHER HELICOBACTER INFECTION INDUCED ISX EXPRESSION. WE ESTABLISHED STABLE MKN45 TRANSFECTED CELLS EXPRESSING ISX (STABLE-ISX MKN45) AND PERFORMED A SPHEROID COLONY FORMATION ASSAY AND A XENOGRAFT MODEL. WE PERFORMED ISX IMMUNOHISTOCHEMISTRY IN CANCER AND ADJACENT GASTRIC TISSUES. RESULTS: ISX EXPRESSION WAS INCREASED IN MOUSE AND HUMAN GASTRIC MUCOSA INFECTED WITH HELICOBACTER. THE PRESENCE OF IM AND H. PYLORI INFECTION IN HUMAN STOMACH WAS CORRELATED WITH ISX EXPRESSION. H. PYLORI INDUCED ISX MRNA AND PROTEIN EXPRESSION. CDX1/2, CYCLIND1, AND MUC2 WERE UPREGULATED IN STABLE-ISX MKN45, WHEREAS MUC5AC WAS DOWNREGULATED. STABLE-ISX MKN45 CELLS FORMED MORE SPHEROID COLONIES, AND HAD HIGH TUMORIGENIC ABILITY. ISX EXPRESSION IN GASTRIC CANCER AND ADJACENT MUCOSA WERE CORRELATED. CONCLUSIONS: ISX EXPRESSION INDUCED BY H. PYLORI INFECTION MAY LEAD TO IM AND HYPERPROLIFERATION OF GASTRIC MUCOSA THROUGH CDX1/2 AND CYCLIND1 EXPRESSION, CONTRIBUTING TO GASTRIC CARCINOGENESIS. 2016 20 106 31 A REVIEW OF MOLECULAR EVENTS OF CADMIUM-INDUCED CARCINOGENESIS. CADMIUM (CD) IS A TOXIC, HEAVY INDUSTRIAL METAL THAT POSES SERIOUS ENVIRONMENTAL HEALTH HAZARDS TO BOTH HUMANS AND WILDLIFE. RECENTLY, CD AND CD-CONTAINING COMPOUNDS HAVE BEEN CLASSIFIED AS KNOWN HUMAN CARCINOGENS, AND EPIDEMIOLOGICAL DATA SHOW CAUSAL ASSOCIATIONS WITH PROSTATE, BREAST, AND LUNG CANCER. THE MOLECULAR MECHANISMS INVOLVED IN CD-INDUCED CARCINOGENESIS ARE POORLY UNDERSTOOD AND ARE ONLY NOW BEGINNING TO BE ELUCIDATED. THE EFFECTS OF CHRONIC EXPOSURE TO CD HAVE RECENTLY ATTRACTED GREAT INTEREST DUE TO THE DEVELOPMENT OF MALIGNANCIES IN CD-INDUCED TUMORIGENESIS IN ANIMALS MODELS. BRIEFLY, VARIOUS IN VITRO STUDIES DEMONSTRATE THAT CD CAN ACT AS A MITOGEN, CAN STIMULATE CELL PROLIFERATION AND INHIBIT APOPTOSIS AND DNA REPAIR, AND CAN INDUCE CARCINOGENESIS IN SEVERAL MAMMALIAN TISSUES AND ORGANS. THUS, THE VARIOUS MECHANISMS INVOLVED IN CHRONIC CD EXPOSURE AND MALIGNANT TRANSFORMATIONS WARRANT FURTHER INVESTIGATION. IN THIS REVIEW, WE FOCUS ON RECENT EVIDENCE OF VARIOUS LEADING GENERAL AND TISSUE-SPECIFIC MOLECULAR MECHANISMS THAT FOLLOW CHRONIC EXPOSURE TO CD IN PROSTATE-, BREAST-, AND LUNG-TRANSFORMED MALIGNANCIES. IN ADDITION, IN THIS REVIEW, WE CONSIDER LESS DEFINED MECHANISMS SUCH AS EPIGENETIC MODIFICATION AND AUTOPHAGY, WHICH ARE THOUGHT TO PLAY A ROLE IN THE DEVELOPMENT OF CD-INDUCED MALIGNANT TRANSFORMATION. 2014