1 1661 141 DOWN-REGULATION OF REDUCED FOLATE CARRIER GENE (RFC1) EXPRESSION AFTER EXPOSURE TO METHOTREXATE IN ZR-75-1 BREAST CANCER CELLS. METHOTREXATE (MTX) IS ADMINISTERED IN INTERVALS OF ONE WEEK OR LONGER IN THE TREATMENT OF CANCER AND AUTOIMMUNE DISEASE. EARLY STUDIES SUGGESTED THAT DAILY MTX ADMINISTRATION WAS ASSOCIATED WITH DECREASED EFFECTIVENESS AND INCREASED TOXICITY, LEADING TO SCHEDULES OF ADMINISTRATION THAT INCLUDE PERIODIC INTERVALS OF REST DURING CHRONIC MTX THERAPY. WE HYPOTHESIZED THAT THESE OBSERVATIONS MAY BE THE RESULT OF THE DOWN-REGULATION OF THE REDUCED FOLATE CARRIER, THE MAJOR ROUTE OF CELLULAR UPTAKE OF BOTH MTX AND THE ENDOGENOUS FOLATES, AFTER MTX EXPOSURE. WE EXPOSED FOLATE-DEPLETED ZR-75-1 BREAST CANCER CELLS TO LOW-DOSE MTX IN THE PRESENCE OF HYPOXANTHINE, ADENOSINE AND THYMIDINE. AFTER 72 H, THE INITIAL RATE OF MTX UPTAKE HAD DECREASED TO 22% OF THE DAY 0 VALUE. WESTERN BLOT ANALYSIS SHOWED DOWN-REGULATION OF RFC1 PROTEIN EXPRESSION, AND NORTHERN BLOT ANALYSIS SHOWED A CORRESPONDING DECREASE IN RFC1 RNA LEVELS. USING AN RT-PCR ASSAY, WE FOUND THAT LEVELS OF RNA TRANSCRIPTS CONTAINING EACH OF THE THREE RFC1 5' NONCODING EXONS WERE DECREASED AFTER EXPOSURE TO MTX, SUGGESTING THAT MTX EXPOSURE CAUSES TRANSCRIPTIONAL DOWN-REGULATION OF RFC1. PROMOTER-REPORTER CONSTRUCT ASSAYS DEMONSTRATED DECREASED ACTIVITY OF RFC1 PROMOTER ELEMENTS UPSTREAM OF THESE EXONS AFTER MTX EXPOSURE. PREEXPOSURE OF THE ZR-75-1 CELLS TO 5-AZACYTIDINE, A DNA METHYLATION INHIBITOR, FURTHER DECREASED MTX UPTAKE RATHER THAN REVERSE THE INHIBITION OF RFC1 ACTIVITY, INDICATING THAT RFC1 DOWN-REGULATION AFTER MTX EXPOSURE IS NOT THE RESULT OF METHYLATION OF THE RFC1 PROMOTER. IN SUMMARY, THESE STUDIES DEMONSTRATE THAT MTX EXPOSURE CAN DOWN-REGULATE RFC1 EXPRESSION AND ACTIVITY. THESE ACUTE, INDUCIBLE, EPIGENETIC CHANGES IN RFC1 EXPRESSION MAY ULTIMATELY BE MOLDED INTO THE MORE PERMANENT GENETIC CHANGES THAT RESULT IN THE TRANSPORT-MEDIATED MTX RESISTANCE THAT HAVE BEEN OBSERVED IN MTX-RESISTANT CELL LINES. 2000 2 3615 35 IN VITRO FOLATE DEFICIENCY INDUCES DEOXYNUCLEOTIDE POOL IMBALANCE, APOPTOSIS, AND MUTAGENESIS IN CHINESE HAMSTER OVARY CELLS. THE GENETIC AND EPIGENETIC EFFECTS OF NUTRITIONAL FOLATE DEFICIENCY WERE STUDIED IN TWO CHINESE HAMSTER OVARY (CHO) CELL LINES. THE CHO-AA8 CELL LINE (HEMIZYGOUS AT THE APRT LOCUS) AND CHO-UV5 (DNA REPAIR-DEFICIENT MUTANT OF AA8) WERE CULTURED IN HAM'S F-12 MEDIUM OR IN CUSTOM-PREPARED HAM'S F-12 MEDIUM LACKING FOLIC ACID, THYMIDINE, AND HYPOXANTHINE. CELLS CULTURED ACUTELY IN THE FOLATE DEFICIENT MEDIUM EXHIBITED INITIAL GROWTH ARREST, FOLLOWED BY MASSIVE CELL DEATH AND DNA FRAGMENTATION INTO NUCLEOSOMAL MULTIMERS CHARACTERISTIC OF APOPTOSIS. ALTHOUGH PROLONGED CULTURE IN THE FOLATE DEFICIENT MEDIUM WAS CYTOSTATIC AND LETHAL TO THE MAJORITY CELLS, MINOR SUBPOPULATIONS IN BOTH CELL LINES FAILED TO INITIATE CELL DEATH, EXHIBITED PHENOTYPIC ABNORMALITIES, AND ADAPTED A SELECTIVE GROWTH ADVANTAGE UNDER MARGINAL FOLATE CONDITIONS. THESE "RESISTANT" CLONES EXHIBITED MAJOR ALTERATIONS IN DEOXYNUCLEOTIDE POOLS ASSOCIATED WITH AN INCREASE IN MUTANT FREQUENCY AT THE APRT LOCUS AS DETECTED BY RESISTANCE TO CYTOTOXICITY IN 8-AZAADENOSINE. THE MUTATION FREQUENCY IN THE DNA REPAIR-DEFICIENT CHO-UV5 CELLS WAS APPROXIMATELY 100-FOLD GREATER THAN THAT IN THE PARENTAL AA8 CLONES, UNDERSCORING THE IMPORTANCE OF DNA REPAIR UNDER CONDITIONS OF FOLATE DEFICIENCY AND NUCLEOTIDE POOL IMBALANCE. THE ENHANCED MUTATION FREQUENCY IN THE DNA REPAIR-COMPETENT FOLATE-DEFICIENT CHO-AA8 CELLS SUGGESTS THAT DNA REPAIR ACTIVITY IS LESS EFFECTIVE UNDER FOLATE-DEFICIENT CONDITIONS. THESE RESULTS ADD TO THE ACCUMULATING CLINICAL AND EXPERIMENTAL EVIDENCE RELATING CHRONIC FOLATE DEFICIENCY TO GENOMIC INSTABILITY AND CARCINOGENESIS. 1994 3 5057 22 PHENOBARBITAL MECHANISTIC DATA AND RISK ASSESSMENT: ENZYME INDUCTION, ENHANCED CELL PROLIFERATION, AND TUMOR PROMOTION. CHRONIC EXPOSURE TO HIGH DOSES OF PHENOBARBITAL (PB) CAUSES HEPATOCELLULAR ADENOMAS IN BOTH MICE AND RATS AND HEPATOCELLULAR CARCINOMAS IN SOME STRAINS OF MICE. LONG-TERM PB THERAPY HAS NOT BEEN FOUND TO CAUSE HUMAN TUMORS. PB IS NOT DNA REACTIVE, AND MOST GENOTOXICITY TESTS HAVE YIELDED NEGATIVE RESULTS. PB HAS BEEN EXTENSIVELY STUDIED AS AN EPIGENETIC, RODENT LIVER TUMOR PROMOTER. AT EXPOSURES CAUSING RODENT LIVER TUMORS, PB HAS MEASURABLE EFFECTS ON HEPATOCYTES: PB INHIBITS CELL-TO-CELL COMMUNICATION; PB INDUCES ENZYMES, INCLUDING P450 CYTOCHROMES; PB STIMULATES PROLIFERATION AND INHIBITS APOPTOSIS OF HEPATOCYTES IN NEOPLASTIC FOCI. THRESHOLD EXPOSURES FOR SOME OF THESE ENDPOINTS COINCIDE WITH THE THRESHOLD EXPOSURE FOR TUMORIGENESIS. 1996 4 1501 15 DNA METHYLATION ANALYSIS OF HUMAN TISSUE-SPECIFIC CONNEXIN GENES. CONNEXINS ARE THE STRUCTURAL PROTEINS OF GAP JUNCTIONS AND THEIR FUNCTIONING AS TUMOR SUPPRESSORS IS WELL KNOWN. EPIGENETIC MODIFICATIONS, SUCH AS METHYLATION OF CONNEXIN GENES, PLAY IMPORTANT ROLES IN REGULATING GENE EXPRESSION. OVER THE PAST DECADE, SEVERAL METHODS HAVE BEEN APPLIED TO CHARACTERIZE DNA METHYLATION-SPECIFIC LOCI OF CONNEXIN GENES. THIS CHAPTER DESCRIBES ANALYSIS OF SELECTIVE CONNEXIN32 AND CONNEXIN43 GENE DNA METHYLATION IN HUMAN GASTRIC TISSUES USING METHYLATION-SPECIFIC PCR, BISULFITE-SPECIFIC PCR SEQUENCING AS WELL AS MASSARRAY TECHNIQUES. 2016 5 2358 31 EPIGENETIC REGULATION OF RAC1 INDUCES SYNAPTIC REMODELING IN STRESS DISORDERS AND DEPRESSION. DEPRESSION INDUCES STRUCTURAL AND FUNCTIONAL SYNAPTIC PLASTICITY IN BRAIN REWARD CIRCUITS, ALTHOUGH THE MECHANISMS PROMOTING THESE CHANGES AND THEIR RELEVANCE TO BEHAVIORAL OUTCOMES ARE UNKNOWN. TRANSCRIPTIONAL PROFILING OF THE NUCLEUS ACCUMBENS (NAC) FOR RHO GTPASE-RELATED GENES, WHICH ARE KNOWN REGULATORS OF SYNAPTIC STRUCTURE, REVEALED A SUSTAINED REDUCTION IN RAS-RELATED C3 BOTULINUM TOXIN SUBSTRATE 1 (RAC1) EXPRESSION AFTER CHRONIC SOCIAL DEFEAT STRESS. THIS WAS ASSOCIATED WITH A REPRESSIVE CHROMATIN STATE SURROUNDING THE PROXIMAL PROMOTER OF RAC1. INHIBITION OF CLASS 1 HISTONE DEACETYLASES (HDACS) WITH MS-275 RESCUED BOTH THE DECREASE IN RAC1 TRANSCRIPTION AFTER SOCIAL DEFEAT STRESS AND DEPRESSION-RELATED BEHAVIOR, SUCH AS SOCIAL AVOIDANCE. WE FOUND A SIMILAR REPRESSIVE CHROMATIN STATE SURROUNDING THE RAC1 PROMOTER IN THE NAC OF SUBJECTS WITH DEPRESSION, WHICH CORRESPONDED WITH REDUCED RAC1 TRANSCRIPTION. VIRAL-MEDIATED REDUCTION OF RAC1 EXPRESSION OR INHIBITION OF RAC1 ACTIVITY IN THE NAC INCREASES SOCIAL DEFEAT-INDUCED SOCIAL AVOIDANCE AND ANHEDONIA IN MICE. CHRONIC SOCIAL DEFEAT STRESS INDUCES THE FORMATION OF STUBBY EXCITATORY SPINES THROUGH A RAC1-DEPENDENT MECHANISM INVOLVING THE REDISTRIBUTION OF SYNAPTIC COFILIN, AN ACTIN-SEVERING PROTEIN DOWNSTREAM OF RAC1. OVEREXPRESSION OF CONSTITUTIVELY ACTIVE RAC1 IN THE NAC OF MICE AFTER CHRONIC SOCIAL DEFEAT STRESS REVERSES DEPRESSION-RELATED BEHAVIORS AND PRUNES STUBBY SPINES. TAKEN TOGETHER, OUR DATA IDENTIFY EPIGENETIC REGULATION OF RAC1 IN THE NAC AS A DISEASE MECHANISM IN DEPRESSION AND REVEAL A FUNCTIONAL ROLE FOR RAC1 IN RODENTS IN REGULATING STRESS-RELATED BEHAVIORS. 2013 6 2942 34 GENETIC AND EPIGENETIC ALTERATIONS OF LTF AT 3P21.3 IN NASOPHARYNGEAL CARCINOMA. TO INVESTIGATE THE ROLES OF LACTOTRANSFERRIN GENE (LTF, ALSO REFERRED TO AS THE LACTOFERRIN GENE, LF), LOCATED AT 3P21.3 WITHIN THE COMMON MINIMAL DELETION REGION, IN THE PATHOGENESIS OF NASOPHARYNGEAL CARCINOMA (NPC), WE FIRST DETECTED ITS EXPRESSION LEVEL IN 33 PRIMARY NPC TISSUES AND 15 CHRONIC NASOPHARYNGITIS TISSUES. ABSENT EXPRESSION OR DOWNREGULATION OF LTF WERE OBSERVED IN 76% (25 OF 33) OF PRIMARY NPC TISSUES. WE FURTHER FOUND THAT 25% (5 OF 20) OF NPC SPECIMENS HAD LOSS OF HETEROZYGOSITY (LOH) AT THE LTF LOCUS. LTF MUTATION ASSESSED BY POLYMERASE CHAIN REACTION SINGLE-STRAND CONFORMATION POLYMORPHISM (PCR-SSCP) AND DNA SEQUENCING WAS NOTED IN 30% (6 OF 20) OF PRIMARY NPC TISSUES. IN ADDITION, HYPER-METHYLATION OF LTF PROMOTER REGION WAS FOUND IN 63.6% (21 OF 33) OF PRIMARY NPC SAMPLES BUT NOT IN CHRONIC NASOPHARYNGITIS TISSUES. THE LTF TRANSCRIPTS IN NPC CELL LINES INCREASED UPON TREATMENT WITH THE DEMETHYLATION COMPOUND, 5-AZA-2-DEOXYCYTIDINE. IN CONCLUSION, OUR DATA INDICATE THAT TWO-HIT SILENCING OF LTF THROUGH GENETIC AND EPIGENETIC CHANGES MAY BE A COMMON AND IMPORTANT EVENT IN THE CARCINOGENESIS OF NPC. 2006 7 865 32 CHRONIC ACRYLAMIDE EXPOSURE IN MALE MICE RESULTS IN ELEVATED DNA DAMAGE IN THE GERMLINE AND HERITABLE INDUCTION OF CYP2E1 IN THE TESTES. ACUTE ACRYLAMIDE EXPOSURE IN MALE RODENTS RESULTS IN REDUCED REPRODUCTIVE PERFORMANCE AND DOMINANT LETHALITY. HOWEVER, THE REPRODUCTIVE EFFECTS OF LOW DOSE CHRONIC EXPOSURE, WHICH BETTER REFLECTS THE NATURE OF HUMAN EXPOSURE, REMAIN FAR LESS CERTAIN. HUMAN DIETARY CONSUMPTION OF ACRYLAMIDE HAS BEEN ESTIMATED AT AN AVERAGE OF 1-4 MICROG/KG BW/DAY. IN ORDER TO SIMULATE THIS EXPOSURE, MALE MICE WERE PROVIDED WITH ACRYLAMIDE (1 MICROG/ML) VIA THEIR DRINKING WATER CONTINUOUSLY FOR SIX MONTHS, WHICH WAS EQUIVALENT TO A HUMAN DOSE OF 10.5 MICROG/ KG BW/DAY. THIS EXPOSURE REGIME INCREASED DNA DAMAGE IN THE SPERMATOZOA, WITHOUT AFFECTING A CONCOMITANT REDUCTION IN OVERALL FERTILITY. THE OFFSPRING OF ACRYLAMIDE TREATED MICE DID NOT HAVE AN INCREASED INCIDENCE OF SKIN PAPILLOMA FORMATION FOLLOWING THE TWO-STAGE TUMOR INDUCTION PROTOCOL. HOWEVER, THE MALE OFFSPRING OF ACRYLAMIDE TREATED FATHERS HAD SIGNIFICANTLY INCREASED LEVELS OF DNA DAMAGE IN THEIR SPERMATOZOA, DESPITE HAVING HAD NO DIRECT TOXICANT EXPOSURE. IT WAS ALSO FOUND THAT THE F0, AND MOST CRUCIALLY, F1 MICE HAD INCREASED LEVELS OF CYP2E1 PROTEIN IN THEIR GERM CELLS. THIS IS SIGNIFICANT AS CYP2E1 IS THE SOLE ENZYME RESPONSIBLE FOR CONVERSION OF ACRYLAMIDE TO ITS HARMFUL METABOLITE GLYCIDAMIDE. THIS ALTERED EXPRESSION MAY BE DUE TO EPIGENETIC ALTERATIONS. ADDITIONALLY, THE F0 AND F1 MICE HAD INCREASED OXIDATIVE ADDUCTS IN THE DNA OF THEIR GERM CELLS, WHICH WAS HYPOTHESIZED TO ARISE AS A BYPRODUCT OF INCREASED CYP2E1 ACTIVITY. THEREFORE, CHRONIC PATERNAL ACRYLAMIDE EXPOSURE IN MICE HAS CONSEQUENCES FOR THEIR OFFSPRING, AND RAISES CONCERNS FOR THE EFFECTS OF ACRYLAMIDE EXPOSURE IN THE HUMAN POPULATION AND THE ACCUMULATED EFFECTS WITH MULTIPLE GENERATIONS OF EXPOSURE. 2016 8 4819 26 OCCURRENCE OF TOXICITY AND CELL PROLIFERATION AFTER A SINGLE GAVAGE ADMINISTRATION OF CHLOROFORM TO MALE F344 RATS. CHLOROFORM, AN INDUSTRIAL SOLVENT AND ONE OF THE MOST COMMON ENVIRONMENTAL CONTAMINANTS WHICH PRODUCES CARCINOGENIC EFFECTS IN THE LIVER AND KIDNEY OF RODENTS, IS NOT GENOTOXIC IN MOST TRADITIONAL BACTERIAL AND MAMMALIAN TEST SYSTEMS. ITS CARCINOGENIC POTENTIAL APPEARS ATTRIBUTABLE TO THE SUSTAINED CELL TURNOVER (REGENERATIVE HYPERPLASIA) WHICH RESULTS FROM CHRONIC CHLOROFORM TOXICITY. IN THIS PRESENT STUDY, CELL PROLIFERATION (REPLICATIVE DNA SYNTHESIS, RDS) AND HISTOPATHOLOGICAL CHANGES IN HEPATOCYTES AND RENAL TUBULAR EPITHELIAL CELLS WERE ASSESSED IN MALE F344 RATS FOLLOWING A SINGLE GAVAGE CHLOROFORM EXPOSURE (50, 150 OR 500 MG/KG). IN ADDITION, BIOCHEMICAL PARAMETERS (BUN, GOT, LDH AND NAG) WERE EXAMINED USING PLASMA AND URINE SAMPLES. CELL PROLIFERATION AND HISTOPATHOLOGICAL CHANGES (E.G. HYPERTROPHY, NECROSIS, VACUOLATION) WERE ONLY SEEN AT THE DOSE OF 500 MG/KG IN THE LIVER AND KIDNEY. AT THE SAME DOSE, ALL BIOCHEMICAL MARKERS WERE INCREASED AT THE 24 TO 48 HR TIME POINTS. THESE RESULTS OBTAINED ARE THUS IN LINE WITH EARLIER FINDINGS POINTING TO EPIGENETIC CARCINOGENICITY. 1998 9 1800 23 EFFECT OF HISTONE DEACETYLASE INHIBITOR ON ETHANOL WITHDRAWAL-INDUCED HYPERALGESIA IN RATS. BACKGROUND: INCREASED PAIN SENSITIVITY IS OBSERVED FOLLOWING ALCOHOL WITHDRAWAL, AND ATTEMPTS TO ALLEVIATE THIS HYPERALGESIA CAN CONTRIBUTE TO THE CYCLE OF ADDICTION. THE AIM OF THIS STUDY WAS TO DETERMINE IF ALCOHOL WITHDRAWAL-INDUCED HYPERALGESIA WAS OBSERVED IN A CHRONIC ETHANOL EXPOSURE MODEL AND IF THIS PAIN WAS AFFECTED BY HISTONE DEACETYLASE INHIBITORS, THUS REVEALING AN EPIGENETIC MECHANISM. METHODS: ADULT MALE SPRAGUE DAWLEY RATS RECEIVED LIEBER-DECARLI LIQUID CONTROL OR ETHANOL (9% V/V) DIET FOR 15 DAYS. MECHANICAL SENSITIVITY WAS MEASURED WITH VON FREY HAIR STIMULATION OF THE HINDPAW DURING ETHANOL ADMINISTRATION AND 24- AND 72-HOUR WITHDRAWAL. RESULTS: ETHANOL WITHDRAWAL PRODUCED SEVERE AND SUSTAINED MECHANICAL HYPERALGESIA, AN EFFECT NOT OBSERVED IN THE CONTROL OR ETHANOL-MAINTAINED GROUPS. FURTHERMORE, THIS HYPERALGESIA WAS ATTENUATED BY THE HISTONE DEACETYLASE INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID TREATMENT. CONCLUSIONS: HEIGHTENED PAIN SENSITIVITY WAS OBSERVED FOLLOWING WITHDRAWAL FROM CHRONIC ETHANOL EXPOSURE, AND HISTONE DEACETYLASE INHIBITORS COULD BE NOVEL TREATMENTS FOR THIS ALCOHOL WITHDRAWAL-INDUCED HYPERALGESIA. 2019 10 2300 38 EPIGENETIC REGULATION OF BDNF EXPRESSION IN THE PRIMARY SENSORY NEURONS AFTER PERIPHERAL NERVE INJURY: IMPLICATIONS IN THE DEVELOPMENT OF NEUROPATHIC PAIN. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IS KNOWN TO BE UP-REGULATED IN THE DORSAL ROOT GANGLION (DRG) AFTER PERIPHERAL NERVE INJURY, AND TO CONTRIBUTE TO NEUROPATHIC PAIN. HERE, WE FOUND THAT THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA AT DAY 7 POST-INJURY WERE INHIBITED ONLY WHEN ANTI-BDNF ANTIBODY WAS INTRATHECALLY ADMINISTRATED AT DAY 2 POST-INJURY. CONSISTENT WITH BEHAVIORAL RESULTS, WESTERN BLOT ANALYSIS SHOWED THAT THE EXPRESSION LEVELS OF BDNF PROTEIN IN THE SPINAL DORSAL HORN WERE MARKEDLY INDUCED DURING EARLY STAGE POST-INJURY. MOREOVER, THE MAXIMAL INCREASE IN BDNF MRNA EXPRESSION IN THE DRG WAS OBSERVED AT DAY 1 POST-INJURY, AND SIGNIFICANTLY ELEVATED LEVELS WERE SUSTAINED FOR AT LEAST 14 DAYS. FOUR OF FIVE BDNF MRNA TRANSCRIPTS WERE UP-REGULATED AFTER NERVE INJURY, AND THE MOST INDUCIBLE TRANSCRIPT WAS EXON I. USING A CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY, WE FOUND THAT NERVE INJURY PROMOTES HISTONE H3 AND H4 ACETYLATION, TRANSCRIPTIONALLY ACTIVE MODIFICATIONS, AT BDNF PROMOTER I AT DAY 1 POST-INJURY, AND THE LEVELS OF HISTONE ACETYLATION REMAIN ELEVATED FOR AT LEAST 7 DAYS. TAKEN TOGETHER, OUR FINDINGS SUGGEST THAT AN INITIAL INCREASE IN BDNF EXON I EXPRESSION CONTROLLED BY EPIGENETIC MECHANISMS MIGHT HAVE A CRUCIAL ROLE IN THE DEVELOPMENT OF NEUROPATHIC PAIN. 2013 11 73 31 A MULTI-GENERATIONAL STUDY ON LOW-DOSE BPA EXPOSURE IN WISTAR RATS: EFFECTS ON MATERNAL BEHAVIOR, FLAVOR INTAKE AND DEVELOPMENT. BISPHENOL A (BPA) IS A COMMON ENDOCRINE DISRUPTOR FOUND AS AN ENVIRONMENTAL AND FOOD CONTAMINANT. IT EXERTS BOTH DEVELOPMENTAL AND BEHAVIORAL EFFECTS, MAINLY WHEN EXPOSURE OCCURS IN EARLY LIFE. THE AIM OF THIS STUDY WAS TO DETERMINE THE MULTI-GENERATIONAL EFFECTS OF CHRONIC, HUMAN-RELEVANT LOW-DOSE EXPOSURE TO BPA ON DEVELOPMENT, MATERNAL BEHAVIOR AND FLAVOR PREFERENCE IN WISTAR RATS. BPA WAS ORALLY ADMINISTERED AT A DAILY DOSE OF 5 MUG/KG BODY WEIGHT TO F0 PREGNANT DAMS FROM THE FIRST DAY OF GESTATION (GD 1) UNTIL THE LAST DAY OF LACTATION (LD 21), AND THEN TO F1 OFFSPRING FROM WEANING (PND 21) TO ADULTHOOD (PND 100). F2 OFFSPRING WERE NOT EXPOSED. DEVELOPMENT AND CLINICAL SIGNS OF TOXICITY WERE ASSESSED DAILY. MATERNAL BEHAVIOR WAS EVALUATED BY OBSERVING NURSING AND PUP-CARING ACTIONS, AS WELL AS "NON-MATERNAL" BEHAVIORS IN F0 AND F1 DAMS FROM PARTURITION UNTIL LD 8. THE FLAVOR PREFERENCES OF F1 AND F2 OFFSPRING WERE EVALUATED BASED ON THE INTAKE OF SWEET, SALT AND FAT SOLUTIONS USING THE TWO-BOTTLE CHOICE TEST ON PND 21-34 AND PND 86-99. BPA EXPOSURE: 1) DECREASED MATERNAL BEHAVIOR IN F1 DAMS, 2) CAUSED DEVELOPMENTAL DEFECTS IN BOTH F1 AND F2 OFFSPRING, WITH A NOTICEABLE DECREASE IN ANOGENITAL DISTANCE IN MALE RATS, AND 3) DID NOT AFFECT FLAVORED SOLUTION INTAKE IN F1, BUT INDUCED CHANGES IN SWEET PREFERENCE IN F2 JUVENILES AND IN SALT AND FAT SOLUTION INTAKES IN F2 ADULTS, AND 4) INDUCED A BODY WEIGHT INCREASE IN THE F2 GENERATION ONLY, WHEREAS FOOD INTAKE AND WATER CONSUMPTION DID NOT CHANGE. TAKEN AS A WHOLE, OUR FINDINGS SHOWED THAT BOTH GESTATIONAL (F0) AND LIFELONG (F1) EXPOSURES TO A HUMAN-RELEVANT DOSE OF BPA COULD INDUCE MULTI-GENERATIONAL EFFECTS ON BOTH DEVELOPMENT AND BEHAVIOR. THESE RESULTS SUGGEST POSSIBLE SELECTIVE NEUROENDOCRINE DEFECTS AND/OR EPIGENETIC CHANGES CAUSED BY BPA EXPOSURE. 2014 12 1819 22 EFFECTS OF CHRONIC OCHRATOXIN A EXPOSURE ON P53 HETEROZYGOUS AND P53 HOMOZYGOUS MICE. EXPOSURE TO THE MYCOTOXIN OCHRATOXIN A (OTA) CAUSES NEPHROPATHY IN DOMESTIC ANIMALS AND RODENTS AND RENAL TUMORS IN RODENTS AND POULTRY. HUMANS ARE EXPOSED TO OTA BY CONSUMING FOODS MADE WITH CONTAMINATED CEREAL GRAINS AND OTHER COMMODITIES. MANAGEMENT OF HUMAN HEALTH RISKS DUE TO OTA EXPOSURE DEPENDS, IN PART, ON ESTABLISHING A MODE OF ACTION (MOA) FOR OTA CARCINOGENESIS. TO FURTHER INVESTIGATE OTA'S MOA, P53 HETEROZYGOUS (P53+/-) AND P53 HOMOZYGOUS (P53+/+) MICE WERE EXPOSED TO OTA IN DIET FOR 26 WEEKS. THE FORMER ARE SUSCEPTIBLE TO TUMORIGENESIS UPON CHRONIC EXPOSURE TO GENOTOXIC CARCINOGENS. OTA-INDUCED RENAL DAMAGE BUT NO TUMORS WERE OBSERVED IN EITHER STRAIN, INDICATING THAT P53 HETEROZYGOSITY CONFERRED LITTLE ADDITIONAL SENSITIVITY TO OTA. RENAL CHANGES INCLUDED DOSE-DEPENDENT INCREASES IN CELLULAR PROLIFERATION, APOPTOSIS, KARYOMEGALY, AND TUBULAR DEGENERATION IN PROXIMAL TUBULES, WHICH WERE CONSISTENT WITH OCHRATOXICOSIS. THE LOWEST OBSERVED EFFECT LEVEL FOR RENAL CHANGES IN P53+/- AND P53+/+ MICE WAS 200 MUG OTA/KG BW/DAY. BASED ON THE LACK OF TUMORS AND THE SEVERITY OF RENAL AND BODY WEIGHT CHANGES AT A MAXIMUM TOLERATED DOSE, THE RESULTS WERE INTERPRETED AS SUGGESTIVE OF A PRIMARILY NONGENOTOXIC (EPIGENETIC) MOA FOR OTA CARCINOGENESIS IN THIS MOUSE MODEL. 2015 13 3619 30 IN VIVO ACUTE ON CHRONIC ETHANOL EFFECTS IN LIVER: A MOUSE MODEL EXHIBITING EXACERBATED INJURY, ALTERED METABOLIC AND EPIGENETIC RESPONSES. CHRONIC ALCOHOLICS WHO ALSO BINGE DRINK (I.E., ACUTE ON CHRONIC) ARE PRONE TO AN EXACERBATED LIVER INJURY BUT ITS MECHANISM IS NOT UNDERSTOOD. WE THEREFORE INVESTIGATED THE IN VIVO EFFECTS OF CHRONIC AND BINGE ETHANOL INGESTION AND COMPARED TO CHRONIC ETHANOL FOLLOWED BY THREE REPEAT BINGE ETHANOL ON THE LIVER OF MALE C57/BL6 MICE FED ETHANOL IN LIQUID DIET (4%) FOR FOUR WEEKS FOLLOWED BY BINGE ETHANOL (INTRAGASTRIC ADMINISTRATION, 3.5 G/KG BODY WEIGHT, THREE DOSES, 12H APART). CHRONIC FOLLOWED BY BINGE ETHANOL EXACERBATED FAT ACCUMULATION, NECROSIS, DECREASE IN HEPATIC SAM AND SAM:SAH RATIO, INCREASE IN ADENOSINE LEVELS, AND ELEVATED CYP2E1 LEVELS. HISTONE H3 LYSINE ACETYLATION (H3ACK9), DUALLY MODIFIED PHOSPHOACETYLATED HISTONE H3 (H3ACK9/PS10), AND PHOSPHORYLATED H2AX INCREASED AFTER BINGE WHEREAS PHOSPHORYLATION OF HISTONE H3 SER 10 (H3S10) AND H3 SER 28 (H3S28) INCREASED AFTER CHRONIC ETHANOL-BINGE. HISTONE H3 LYSINE 4 AND 9 DIMETHYLATION INCREASED WITH A MARKED DIMETHYLATION IN H3K9 IN CHRONIC ETHANOL BINGE GROUP. TRIMETHYLATED HISTONE H3 LEVELS DID NOT CHANGE. NUCLEAR LEVELS OF HISTONE ACETYL TRANSFERASE GCN5 AND HISTONE DEACETYLASE HDAC3 WERE ELEVATED WHEREAS PHOSPHO-CREB DECREASED IN A DISTINCTIVE MANNER. TAKEN TOGETHER, ACUTE ON CHRONIC ETHANOL INGESTION CAUSED AMPLIFICATION OF LIVER INJURY AND ELICITED CHARACTERISTIC PROFILES OF HISTONE MODIFICATIONS, METABOLIC ALTERATIONS, AND CHANGES IN NUCLEAR PROTEIN LEVELS. THESE FINDINGS DEMONSTRATE THAT CHRONIC ETHANOL EXPOSURE RENDERS LIVER MORE SUSCEPTIBLE TO REPEAT ACUTE/BINGE ETHANOL INDUCED ACCELERATION OF ALCOHOLIC LIVER DISEASE. 2015 14 5357 33 REACTIVE OXYGEN SPECIES INDUCE EPIGENETIC INSTABILITY THROUGH THE FORMATION OF 8-HYDROXYDEOXYGUANOSINE IN HUMAN HEPATOCARCINOGENESIS. CHRONIC HEPATITIS C (CHC) TRIGGERS OXIDATIVE STRESS AND CONTRIBUTES TO THE EMERGENCE OF HEPATOCELLULAR CARCINOMA (HCC). WE PREVIOUSLY REPORTED THAT TUMOR SUPPRESSOR GENE (TSG) METHYLATION IS A CRITICAL FACTOR DURING THE EARLY STAGES OF HEPATOCARCINOGENESIS. IN THIS STUDY, WE CLARIFY THE ASSOCIATION BETWEEN OXIDATIVE STRESS AND EPIGENETIC ALTERATIONS DURING HEPATOCARCINOGENESIS. WE EXAMINED DNA OXIDATION AND METHYLATION PROFILES IN 128 LIVER BIOPSY SAMPLES FROM CHC PATIENTS. THE DNA OXIDATION AND METHYLATED TSG NUMBERS WERE QUANTIFIED USING IMMUNOHISTOCHEMICAL ANALYSIS OF 8-HYDROXYDEOXYGUANOSINE (8-OHDG) AND QUANTITATIVE PCR FOR 11 TSGS, RESPECTIVELY. THE QUANTITATIVE CHROMATIN IMMUNOPRECIPITATION-PCR (CHIP-QPCR) ASSAY IN HEPG2 AND FETAL LIVER HC CELLS TREATED WITH H2O2 WAS USED TO QUANTIFY TRIMETHYL-H3K4, ACETYLATED-H4K16 (AN ACTIVE CHROMATIN MARKER), TRIMETHYL-H3K27 (A REPRESSIVE CHROMATIN MARKER) AND 8-OHDG. WE ANALYZED 30 PROMOTERS OF 25 DIFFERENT TSGS BY QPCR. THE HIGH LEVELS OF 8-OHDG WAS THE ONLY VARIABLE THAT WAS SIGNIFICANTLY ASSOCIATED WITH THE INCREASED NUMBER OF METHYLATED TSGS IN CHC (P < 0.0001). THE CHIP-QPCR REVEALED THAT AFTER H2O2 TREATMENT OF THE CELL LINES, THE 8-OHDG-BOUND PROMOTERS SHOWED A MODIFICATION FROM AN ACTIVE CHROMATIN (TRIMETHYL-H3K4 AND ACETYLATED-H4K16 DOMINANT) TO A REPRESSIVE CHROMATIN (TRIMETHYL-H3K27 DOMINANT) STATUS. WE CONCLUDE THAT OXIDATIVE STRESS ALTERS THE CHROMATIN STATUS, WHICH LEADS TO ABNORMAL METHYLATION OF TSGS, AND CONTRIBUTES TO HEPATOCARCINOGENESIS IN CHC PATIENTS. 2013 15 2156 39 EPIGENETIC MECHANISMS ARE INVOLVED IN THE REGULATION OF ETHANOL CONSUMPTION IN MICE. BACKGROUND: REPEATED ALCOHOL EXPOSURE IS KNOWN TO INCREASE SUBSEQUENT ETHANOL CONSUMPTION IN MICE. HOWEVER, THE UNDERLYING MECHANISMS HAVE NOT BEEN FULLY ELUCIDATED. ONE POSTULATED MECHANISM INVOLVES EPIGENETIC MODIFICATIONS, INCLUDING HISTONE MODIFICATIONS AND DNA METHYLATION OF RELEVANT GENES SUCH AS NR2B OR BDNF. METHODS: TO INVESTIGATE THE ROLE OF EPIGENETIC MECHANISMS IN THE DEVELOPMENT OF ALCOHOL DRINKING BEHAVIOR, AN ESTABLISHED CHRONIC INTERMITTENT ETHANOL EXPOSURE REINFORCED ETHANOL DRINKING MOUSE MODEL WITH VAPOR INHALATION OVER TWO 9-DAY TREATMENT REGIMENS WAS USED. THE DNA METHYLTRANSFERASE INHIBITOR, 5-AZACYTIDINE OR THE HISTONE DEACETYLASE INHIBITOR, TRICHOSTATIN A WAS ADMINISTERED (INTRAPERITONEALLY) TO C57BL/6 MICE 30 MIN BEFORE DAILY EXPOSURE TO CHRONIC INTERMITTENT ETHANOL. CHANGES IN ETHANOL CONSUMPTION WERE MEASURED USING THE 2-BOTTLE CHOICE TEST. RESULTS: THE RESULTS INDICATED THAT SYSTEMIC ADMINISTRATION OF TRICHOSTATIN A (2.5 MICROG/G) FACILITATED CHRONIC INTERMITTENT ETHANOL-INDUCED ETHANOL DRINKING, BUT SYSTEMIC ADMINISTRATION OF 5-AZACYTIDINE (2 MICROG/G) DID NOT CAUSE THE SAME EFFECT. HOWEVER, WHEN 5-AZACYTIDINE WAS ADMINISTERED BY INTRACEREBROVENTRICULAR INJECTION, IT FACILITATED CHRONIC INTERMITTENT ETHANOL-INDUCED ETHANOL DRINKING. FURTHERMORE, THE INCREASED DRINKING CAUSED BY CHRONIC INTERMITTENT ETHANOL WAS PREVENTED BY INJECTION OF A METHYL DONOR, S-ADENOSYL-L-METHIONINE. TO PROVIDE EVIDENCE THAT CHRONIC INTERMITTENT ETHANOL- OR TRICHOSTATIN A-INDUCED DNA DEMETHYLATION AND HISTONE MODIFICATIONS OF THE NR2B PROMOTER MAY UNDERLIE THE ALTERED ETHANOL CONSUMPTION, WE EXAMINED EPIGENETIC MODIFICATIONS AND NR2B EXPRESSION IN THE PREFRONTAL CORTEX OF THESE MICE. CHRONIC INTERMITTENT ETHANOL OR TRICHOSTATIN A DECREASED DNA METHYLATION AND INCREASED HISTONE ACETYLATION IN THE NR2B GENE PROMOTER, AS WELL AS MRNA LEVELS OF NR2B IN THESE MICE. CONCLUSIONS: TAKEN TOGETHER, THESE RESULTS INDICATE THAT EPIGENETIC MODIFICATIONS ARE INVOLVED IN REGULATING ETHANOL DRINKING BEHAVIOR, PARTIALLY THROUGH ALTERING NR2B EXPRESSION. 2014 16 4275 30 MICROGLIA ACTIVATION IN THE MIDBRAIN OF THE HUMAN NEONATE: THE EFFECT OF PERINATAL HYPOXIC-ISCHEMIC INJURY. PERINATAL HYPOXIA-ISCHEMIA (PHI) IS A MAJOR RISK FACTOR FOR THE DEVELOPMENT OF NEUROPSYCHIATRIC DEFICITS LATER IN LIFE. WE PREVIOUSLY REPORTED THAT AFTER PROLONGED PHI, THE DOPAMINERGIC NEURONS OF THE HUMAN NEONATE SHOWED A DRAMATIC REDUCTION OF TYROSINE HYDROXYLASE (TH) IN THE SUBSTANTIA NIGRA, WITHOUT IMPORTANT SIGNS OF NEURONAL DEGENERATION DESPITE THE SIGNIFICANT REDUCTION IN THEIR CELL SIZE. SINCE MICROGLIA ACTIVATION COULD PRECEDE NEURONAL DEATH, WE NOW INVESTIGATED 2 MICROGLIA ACTIVATION MARKERS, IONIZED CALCIUM-BINDING ADAPTER MOLECULE 1 (IBA1), AND THE PHAGOCYTOSIS MARKER CD68. THE HIGHEST IBA1 IMMUNOREACTIVITY WAS FOUND IN NEONATES WITH NEUROPATHOLOGICAL LESIONS OF SEVERE/ABRUPT PHI, WHILE THE LOWEST IN SUBJECTS WITH MODERATE/PROLONGED OR OLDER PHI. SUBJECTS WITH VERY SEVERE/PROLONGED OR CHRONIC PHI SHOWED AN INCREASED IBA1 EXPRESSION AND VERY ACTIVATED MICROGLIAL MORPHOLOGY. HEAVY ATTACHMENT OF MICROGLIA ON TH NEURONS AND REMARKABLE EXPRESSION OF CD68 WERE ALSO OBSERVED INDICATING PHAGOCYTOSIS IN THIS GROUP. FEMALES APPEAR TO EXPRESS MORE IBA1 THAN MALES, SUGGESTING A GENDER DIFFERENCE IN MICROGLIA MATURATION AND IMMUNE REACTIVITY AFTER PHI INSULT. PHI-INDUCED MICROGLIAL "PRIMING" DURING THE SENSITIVE FOR BRAIN DEVELOPMENT PERINATAL/NEONATAL PERIOD, IN COMBINATION WITH GENETIC OR OTHER EPIGENETIC FACTORS, COULD PREDISPOSE THE SURVIVORS TO NEUROPSYCHIATRIC DISORDERS LATER IN LIFE, POSSIBLY THROUGH A SEXUALLY DIMORPHIC WAY. 2022 17 1399 39 DIET-INDUCED OBESITY MODULATES EPIGENETIC RESPONSES TO IONIZING RADIATION IN MICE. BOTH EXPOSURE TO IONIZING RADIATION AND OBESITY HAVE BEEN ASSOCIATED WITH VARIOUS PATHOLOGIES INCLUDING CANCER. THERE IS A CRUCIAL NEED IN BETTER UNDERSTANDING THE INTERACTIONS BETWEEN IONIZING RADIATION EFFECTS (ESPECIALLY AT LOW DOSES) AND OTHER RISK FACTORS, SUCH AS OBESITY. IN ORDER TO EVALUATE RADIATION RESPONSES IN OBESE ANIMALS, C3H AND C57BL/6J MICE FED A CONTROL NORMAL FAT OR A HIGH FAT (HF) DIET WERE EXPOSED TO FRACTIONATED DOSES OF X-RAYS (0.75 GY X4). BONE MARROW MICRONUCLEUS ASSAYS DID NOT SUGGEST A MODULATION OF RADIATION-INDUCED GENOTOXICITY BY HF DIET. USING MSP, WE OBSERVED THAT THE PROMOTERS OF P16 AND DAPK GENES WERE METHYLATED IN THE LIVERS OF C57BL/6J MICE FED A HF DIET (IRRADIATED AND NON-IRRADIATED); MGMT PROMOTER WAS METHYLATED IN IRRADIATED AND/OR HF DIET-FED MICE. IN ADDITION, METHYLATION PCR ARRAYS IDENTIFIED EP300 AND SOCS1 (WHOSE PROMOTERS EXHIBITED HIGHER METHYLATION LEVELS IN NON-IRRADIATED HF DIET-FED MICE) AS POTENTIAL TARGETS FOR FURTHER STUDIES. WE THEN COMPARED MICRORNA REGULATIONS AFTER RADIATION EXPOSURE IN THE LIVERS OF C57BL/6J MICE FED A NORMAL OR AN HF DIET, USING MICRORNA ARRAYS. INTERESTINGLY, RADIATION-TRIGGERED MICRORNA REGULATIONS OBSERVED IN NORMAL MICE WERE NOT OBSERVED IN OBESE MICE. MIR-466E WAS UPREGULATED IN NON-IRRADIATED OBESE MICE. IN VITRO FREE FATTY ACID (PALMITIC ACID, OLEIC ACID) ADMINISTRATION SENSITIZED AML12 MOUSE LIVER CELLS TO IONIZING RADIATION, BUT THE INHIBITION OF MIR-466E COUNTERACTED THIS RADIO-SENSITIZATION, SUGGESTING THAT THE MODULATION OF RADIATION RESPONSES BY DIET-INDUCED OBESITY MIGHT INVOLVE MIR-466E EXPRESSION. ALL TOGETHER, OUR RESULTS SUGGESTED THE EXISTENCE OF DIETARY EFFECTS ON RADIATION RESPONSES (ESPECIALLY EPIGENETIC REGULATIONS) IN MICE, POSSIBLY IN RELATIONSHIP WITH OBESITY-INDUCED CHRONIC OXIDATIVE STRESS. 2014 18 3331 33 HISTONE DEACETYLASE INHIBITOR SUBERANILOHYDROXAMIC ACID TREATMENT REVERSES HYPOSENSITIVITY TO GAMMA-AMINOBUTYRIC ACID IN THE VENTRAL TEGMENTAL AREA DURING ETHANOL WITHDRAWAL. BACKGROUND: THE VENTRAL TEGMENTAL AREA (VTA) IS IMPORTANT FOR ALCOHOL-RELATED REWARD AND REINFORCEMENT. MOUSE VTA NEURONS ARE HYPOSENSITIVE TO GAMMA-AMINOBUTYRIC ACID (GABA) DURING ETHANOL (ETOH) WITHDRAWAL, AND GABA RESPONSIVENESS IS NORMALIZED BY IN VITRO TREATMENT WITH HISTONE DEACETYLASE INHIBITORS (HDACI). THE PRESENT STUDY EXAMINED THE EFFECT OF A SYSTEMICALLY ADMINISTERED HDACI, SUBERANILOHYDROXAMIC ACID (SAHA) ON GABA SENSITIVITY, AND RELATED MOLECULAR CHANGES IN VTA NEURONS DURING WITHDRAWAL AFTER CHRONIC ETOH INTAKE IN RATS. METHODS: SPRAGUE DAWLEY MALE ADULT RATS WERE FED WITH LIEBER-DECARLI DIET (9% ETOH OR CONTROL DIET) FOR 16 DAYS. EXPERIMENTAL GROUPS INCLUDED CONTROL DIET-FED AND ETOH DIET-FED (0- OR 24-HOUR WITHDRAWAL) RATS TREATED WITH EITHER SAHA OR VEHICLE INJECTION. SINGLE-UNIT RECORDINGS WERE USED TO MEASURE THE RESPONSE OF VTA NEURONS TO GABA. IMMUNOHISTOCHEMISTRY WAS PERFORMED TO EXAMINE LEVELS OF HDAC2, ACETYLATED HISTONE H3 LYSINE 9 (ACH3K9), AND GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS IN THE VTA; QUANTITATIVE POLYMERASE CHAIN REACTION WAS PERFORMED TO EXAMINE THE MRNA LEVELS OF HDAC2 AND GABA(A) RECEPTOR SUBUNITS. RESULTS: VTA NEURONS FROM THE WITHDRAWAL GROUP EXHIBITED GABA HYPOSENSITIVITY. IN VIVO SAHA TREATMENT 2 HOURS BEFORE SACRIFICE NORMALIZED THE SENSITIVITY OF VTA NEURONS TO GABA. ETOH WITHDRAWAL WAS ASSOCIATED WITH INCREASED HDAC2 AND DECREASED ACH3K9 PROTEIN LEVELS; SAHA TREATMENT NORMALIZED ACH3K9 LEVELS. INTERESTINGLY, NO SIGNIFICANT CHANGE WAS OBSERVED IN THE MRNA LEVELS OF HDAC2. THE MRNA LEVELS, BUT NOT PROTEIN LEVELS, OF GABA(A) RECEPTOR ALPHA1 AND ALPHA5 SUBUNITS WERE INCREASED DURING WITHDRAWAL. CONCLUSIONS: WITHDRAWAL FROM CHRONIC ETOH EXPOSURE RESULTS IN A DECREASE IN GABA-MEDIATED INHIBITION, AND THIS GABA HYPOSENSITIVITY IS NORMALIZED BY IN VIVO SAHA TREATMENT. DISRUPTION OF SIGNALING IN THE VTA PRODUCED BY ALTERATION OF GABA NEUROTRANSMISSION COULD BE 1 NEUROADAPTIVE PHYSIOLOGICAL PROCESS LEADING TO CRAVING AND RELAPSE. THESE RESULTS SUGGEST THAT HDACI PHARMACOTHERAPY WITH AGENTS LIKE SAHA MIGHT BE AN EFFECTIVE TREATMENT FOR ALCOHOLISM. 2018 19 894 26 CHRONIC ETHANOL FEEDING ALTERS HEPATOCYTE MEMORY WHICH IS NOT ALTERED BY ACUTE FEEDING. BACKGROUND: GENE EXPRESSION CHANGES IN THE LIVER AFTER ACUTE BINGE DRINKING MAY DIFFER FROM THE CHANGES SEEN IN CHRONIC ETHANOL FEEDING IN THE RAT. THE CHANGES IN GENE EXPRESSION AFTER CHRONIC ETHANOL FEEDING MAY SENSITIZE THE LIVER TO ALCOHOL-INDUCED LIVER DAMAGE, WHICH IS NOT SEEN AFTER ACUTE BINGE DRINKING. METHODS: TO TEST THIS HYPOTHESIS, GENE MICROARRAY ANALYSIS WAS PERFORMED ON THE LIVERS OF RATS (N = 3) FED AN ACUTE BINGE DOSE OF ETHANOL (6 G/KG BODY WT) AND KILLED AT 3 AND 12 HOURS AFTER ETHANOL BY GAVAGE. THE GENE MICROARRAYS WERE COMPARED WITH THOSE MADE ON THE LIVER OF RATS FROM A PREVIOUS STUDY, IN WHICH THE RATS WERE FED ETHANOL BY INTRAGASTRIC TUBE FOR 1 MONTH (36% OF CALORIES DERIVED FROM ETHANOL). RESULTS: MICROARRAY ANALYSIS DATA VARIED BETWEEN THE ACUTE AND CHRONIC MODELS IN SEVERAL IMPORTANT RESPECTS. GROWTH FACTORS INCREASED MAINLY IN THE CHRONIC ALCOHOL FED RAT. CHANGES IN ENZYMES INVOLVED IN OXIDATIVE STRESS WERE NOTED ONLY WITH CHRONIC ETHANOL FEEDING. GENE EXPRESSION OF FAT METABOLISM WAS INCREASED ONLY WITH CHRONIC ETHANOL FEEDING. MOST IMPORTANTLY, EPIGENETIC RELATED ENZYMES AND ACETYLATION AND METHYLATION OF HISTONES CHANGED ONLY AFTER CHRONIC ETHANOL FEEDING. CONCLUSIONS: THE RESULTS SUPPORT THE CONCEPT THAT CHRONIC ETHANOL INGESTION INDUCES ALTERED GENE EXPRESSION AS A RESULT OF CHANGES IN EPIGENETIC MECHANISMS, WHERE ACETYLATION AND METHYLATION OF HISTONES WERE ALTERED. 2009 20 708 33 BYSTANDER EFFECTS IN RADIATION-INDUCED GENOMIC INSTABILITY. EXPOSURE OF GM10115 HAMSTER-HUMAN HYBRID CELLS TO X-RAYS CAN RESULT IN THE INDUCTION OF CHROMOSOMAL INSTABILITY IN THE PROGENY OF SURVIVING CELLS. THIS INSTABILITY MANIFESTS AS THE DYNAMIC PRODUCTION OF NOVEL SUB-POPULATIONS OF CELLS WITH UNIQUE CYTOGENETIC REARRANGEMENTS INVOLVING THE "MARKER" HUMAN CHROMOSOME. WE HAVE USED THE COMET ASSAY TO INVESTIGATE WHETHER THERE WAS AN ELEVATED LEVEL OF ENDOGENOUS DNA BREAKS IN CHROMOSOMALLY UNSTABLE CLONES THAT COULD PROVIDE A SOURCE FOR THE CHROMOSOMAL REARRANGEMENTS AND THUS ACCOUNT FOR THE PERSISTENT INSTABILITY OBSERVED. OUR RESULTS INDICATE NO SIGNIFICANT DIFFERENCE IN COMET TAIL MEASUREMENT BETWEEN NON-IRRADIATED AND RADIATION-INDUCED CHROMOSOMALLY UNSTABLE CLONES. USING TWO-COLOR FLUORESCENCE IN SITU HYBRIDIZATION WE ALSO INVESTIGATED WHETHER RECOMBINATIONAL EVENTS INVOLVING THE INTERSTITIAL TELOMERE REPEAT-LIKE SEQUENCES IN GM10115 CELLS WERE INVOLVED AT FREQUENCIES HIGHER THAN RANDOM PROCESSES WOULD OTHERWISE PREDICT. NINE OF 11 CLONES DEMONSTRATED A SIGNIFICANTLY HIGHER THAN EXPECTED INVOLVEMENT OF THESE INTERSTITIAL TELOMERE REPEAT-LIKE SEQUENCES AT THE RECOMBINATION JUNCTION BETWEEN THE HUMAN AND HAMSTER CHROMOSOMES. SINCE ELEVATED LEVELS OF ENDOGENOUS BREAKS WERE NOT DETECTED IN UNSTABLE CLONES WE PROPOSE THAT EPIGENETIC OR BYSTANDER EFFECTS (BSES) LEAD TO THE ACTIVATION OF RECOMBINATIONAL PATHWAYS THAT PERPETUATE THE UNSTABLE PHENOTYPE. SPECIFICALLY, WE EXPAND UPON THE HYPOTHESIS THAT RADIATION INDUCES CONDITIONS AND/OR FACTORS THAT STIMULATE THE PRODUCTION OF REACTIVE OXYGEN SPECIES (ROS). THESE REACTIVE INTERMEDIATES THEN CONTRIBUTE TO A CHRONIC PRO-OXIDANT ENVIRONMENT THAT CYCLES OVER MULTIPLE GENERATIONS, PROMOTING CHROMOSOMAL RECOMBINATION AND OTHER PHENOTYPES ASSOCIATED WITH GENOMIC INSTABILITY. 2002