1 203 130 ACTIVATION OF EPIGENETIC REGULATOR KDM6B BY SALMONELLA TYPHIMURIUM ENABLES CHRONIC INFECTIONS. NON-TYPHOIDAL SALMONELLA (NTS) INFECTIONS RESULT IN SELF LIMITING GASTROENTERITIS EXCEPT IN RARE CASES WHEREIN MANIFESTATIONS OF CHRONIC INFECTIONS CAN OCCUR. STRATEGIES EMPLOYED BY SALMONELLA TO THRIVE IN HOSTILE ENVIRONMENTS OF HOST DURING CHRONIC INFECTIONS ARE COMPLEX AND MULTIFACETED. IN CHRONIC STATE, A COORDINATED ACTION OF BACTERIAL EFFECTORS ALLOWS REPROGRAMMING OF MACROPHAGES TO M2 SUBTYPE AND THEREBY CREATING A PERMISSIBLE REPLICATIVE NICHE. THE MECHANISTIC DETAILS OF THESE PROCESSES ARE NOT FULLY KNOWN. IN THE CURRENT STUDY WE IDENTIFIED, HISTONE H3-LYSINE 27 TRIMETHYLATION (H3K27ME3)-SPECIFIC DEMETHYLASE, KDM6B TO BE UPREGULATED IN BOTH CELL CULTURE AND IN MURINE MODEL OF SALMONELLA INFECTION. KDM6B RECRUITMENT UPON INFECTION EXHIBITED AN ASSOCIATED LOSS OF OVERALL H3K27ME3 IN HOST CELLS AND WAS SALMONELLA SPI1 EFFECTORS COORDINATED. CHIP-QRT-PCR ARRAY ANALYSIS REVEALED SEVERAL NEW GENE PROMOTER TARGETS OF KDM6B DEMETHYLASE ACTIVITY INCLUDING PPARDELTA, A CRUCIAL REGULATOR OF FATTY ACID OXIDATION PATHWAY AND SALMONELLA-PERSISTENT INFECTIONS. FURTHERMORE, PHARMACOLOGICAL INHIBITION OF KDM6B DEMETHYLASE ACTIVITY WITH GSKJ4 IN CHRONIC SALMONELLA INFECTION MICE MODEL LED TO A SIGNIFICANT REDUCTION IN PATHOGEN LOAD AND M2 MACROPHAGE POLARIZATION IN PERIPHERAL LYMPHOID ORGANS. THE FOLLOWING WORK THUS REVEALS SALMONELLA EFFECTOR-MEDIATED EPIGENETIC REPROGRAMMING OF MACROPHAGES RESPONSIBLE FOR ITS LONG-TERM SURVIVAL AND CHRONIC CARRIAGE. 2021 2 6296 25 THE PROSPECTS FOR A SIMPLIFIED AND INTERNATIONALLY HARMONIZED APPROACH TO THE DETECTION OF POSSIBLE HUMAN CARCINOGENS AND MUTAGENS. IT IS PROPOSED THAT THE MANY SETS OF REGULATORY GUIDELINES FOR THE ASSESSMENT OF CHEMICAL CARCINOGENICITY AND MUTAGENICITY SHOULD BE SIMPLIFIED AND HARMONIZED IN LIGHT OF CURRENT EXPERIMENTAL DATA. DATA ARE DISCUSSED WHICH ILLUSTRATE THAT AN ABSOLUTE DISTINCTION WOULD BE DRAWN BETWEEN ASSAYS CONDUCTED IN VITRO FROM THOSE IN VIVO, AND THAT THE GENOTOXICITY OF A CHEMICAL CAN BE ADEQUATELY DEFINED USING A COMBINATION OF THE SALMONELLA MUTATION ASSAY AND ONE FOR THE ASSESSMENT OF CHROMOSOME ABERRATIONS IN VITRO. IT IS SPECIFICALLY RECOMMENDED THAT ONCE A CHEMICAL HAS SHOWN A CLEAR POSITIVE RESPONSE IN VITRO, FURTHER SHORT-TERM ASSAYS SHOULD BE CONDUCTED IN VIVO; THIS AVOIDS CONSIDERING THE 'WEIGHT OF EVIDENCE' OF IN VITRO DATA, THE DANGERS OF WHICH ARE ILLUSTRATED. IT HAS NOW BEEN UNEQUIVOCALLY ESTABLISHED THAT NOT ALL IN VITRO GENOTOXINS PROVE CARCINOGENIC TO MAMMALS. IT IS THEREFORE RECOMMENDED THAT ALL NEW IN VITRO GENOTOXINS SHOULD BE ASSESSED IN VIVO USING THE MOUSE BONE MARROW MICRONUCLEUS ASSAY, AND IF A NEGATIVE RESPONSE IS OBSERVED, A LIVER GENOTOXICITY TEST. AT PRESENT AN ASSAY FOR THE INDUCTION OF UNSCHEDULED DNA SYNTHESIS (UDS) IN THE LIVER IS THE MOST WELL DEVELOPED FOR THIS PURPOSE. CURRENT DATA INDICATE THAT AN IN VITRO GENOTOXIN FOUND TO BE INACTIVE IN THESE TWO IN VIVO ASSAYS WILL BE NEITHER CARCINOGENIC NOR MUTAGENIC TO THE GERM CELLS OF MAMMALS. EQUALLY, GENOTOXICITY PRODUCED IN MAMMALS INDICATES A CARCINOGENIC AND MUTAGENIC POTENTIAL WHICH CAN USUALLY ONLY BE COUNTERED BY APPROPRIATE CHRONIC BIOASSAYS. THE USE OF SHORT-TERM IN VIVO ASSAYS IN THIS CRITICAL ROLE REQUIRES ATTENTION TO THE SELECTION OF APPROPRIATE DOSE-LEVELS AND ROUTES OF EXPOSURE - THESE ISSUES ARE DISCUSSED. THE ABOVE TESTING STRATEGY WILL NOT DETECT CERTAIN ANIMAL CARCINOGENS, SOME OF WHICH ARE SPECIFICALLY DISCUSSED. THESE CARCINOGENS HAVE BEEN VARIOUSLY REFERRED TO IN THE LITERATURE AS EPIGENETIC/NON-GENOTOXIC/HORMONAL/TOXIC/AMBIGUOUS OR AMBIVALENT CARCINOGENS. IT IS SUGGESTED THAT THEY PRESENT A MINOR POTENTIAL HAZARD TO MAN WHEN COMPARED WITH THAT OF GENOTOXIC CARCINOGENS AND THAT THEIR SHORT-TERM DETECTION CAN ONLY BE ACHIEVED BY THE DEVELOPMENT OF NEW WHOLE MAMMAL ASSAYS EMPLOYING NON-GENETIC ENDPOINTS. THIS IS IN CONTRAST TO THE PRESENT TENDENCY TO EMPLOY ADDITIONAL GENOTOXICITY ASSAYS FOR THEIR DETECTION IN THE UNJUSTIFIED BELIEF THAT THEY POSSESS AN EXQUISITE SPECIFICITY OF GENOTOXIC ACTION. THIS ARTICLE REPRESENTS A PERSONAL VIEW, BUT THE TESTING STRATEGY PROPOSED IS BASED TO A LARGE EXTENT ON THE ORIGINAL THREE-TIER APPROACH OF BRIDGES.(ABSTRACT TRUNCATED AT 400 WORDS) 1986 3 4474 28 MOLECULAR PATHOGENESIS OF GALLBLADDER CANCER: AN UPDATE. GALLBLADDER CARCINOMA (GBC) IS THE MOST AGGRESSIVE GASTROINTESTINAL MALIGNANCY THROUGHOUT THE WORLD, WITH WIDE GEOGRAPHICAL VARIANCE. IT IS THE SUBTYPE OF BILIARY TRACT MALIGNANCY THAT HAS THE POOREST PROGNOSIS AND LOWER SURVIVAL AMONG ALL BILIARY TRACT MALIGNANCIES. VARIOUS FACTORS ARE ASSOCIATED WITH GBC PATHOGENESIS SUCH AS ENVIRONMENTAL, MICROBIAL, METABOLIC AND MOLECULAR. CHRONIC INFLAMMATION OF GALLBLADDER DUE TO PRESENCE OF GALLSTONE OR MICROBIAL INFECTION (EG. SALMONELLA OR H. PYLORI) RESULTS IN SUSTAINED PRODUCTION OF INFLAMMATORY MEDIATORS IN THE TISSUE MICROENVIRONMENT, WHICH CAN CAUSE GENOMIC CHANGES LINKED TO CARCINOGENESIS. GENETIC ALTERATIONS ARE ONE OF THE MAJOR FACTORS, ASSOCIATED WITH AGGRESSIVENESS AND PROGNOSIS. RESEARCHES HAVE BEEN DONE TO EXPLORE SUITABLE BIOMARKER FOR EARLY DIAGNOSIS AND IDENTIFY ALTERED MOLECULAR PATHWAYS TO DEVELOP APPROPRIATE BIOMARKERS FOR EARLY DIAGNOSIS, THERAPY AND PREDICTING PROGNOSIS. DIFFERENT AGENTS FOR TARGETED THERAPY AGAINST ACTIONABLE MUTATIONS OF MOLECULES LIKE EGFR, VEGF, MTOR, HER2, PDL-1, PD-1, MET, PI3K, N-CADHERIN, VEGFR, MEK1 AND MEK2 ARE BEING TRIED. DESPITE THESE ADVANCEMENTS, THERE IS DISMAL IMPROVEMENT IN THE SURVIVAL OF GBC PATIENTS. GENETIC ABERRATIONS OTHER THAN ACTIONABLE MUTATIONS AND EPIGENETIC MODIFICATION INCLUDING ABERRANT EXPRESSIONS OF MICRO-RNAS, ARE ALSO BEING STUDIED BOTH AS DIAGNOSTIC BIOMARKER AND THERAPEUTIC TARGETS. COMPLEX PATHOGENESIS OF GBC STILL NEEDS TO BE UNFOLDED. IN THIS REVIEW WE FOCUS ON THE MOLECULAR PATHOGENESIS OF GBC ELUCIDATED TILL DATE ALONG WITH FUTURE DIRECTIONS THAT CAN BE EXPLORED TO ACHIEVE BETTER MANAGEMENT OF GBC PATIENTS. 2019 4 6032 22 THE CARCINOGENIC INITIATING AND PROMOTING PROPERTIES OF A LIGHTLY REFINED PARAFFINIC OIL. THE DERMAL CARCINOGENIC POTENTIAL OF SOME PETROLEUM-DERIVED LIQUIDS IS RELATED TO THE POLYCYCLIC AROMATIC HYDROCARBON (PAH) CONTENT. HOWEVER, REPEATED APPLICATION OF MIDDLE DISTILLATES (MDS), E.G., KEROSENE, DIESEL FUEL, AND HEATING OIL, PRODUCED TUMORS IN MOUSE SKIN. THIS RESULT WAS UNEXPECTED SINCE THE MDS TYPICALLY CONTAIN VERY LOW LEVELS OF BIOLOGICALLY ACTIVE PAHS. THE PRESENT STUDY EXAMINED THE TUMORIGENIC MECHANISM OF A LIGHTLY REFINED PARAFFINIC OIL (LRPO), AN MD SHOWN TO BE ACTIVE IN MOUSE SKIN. THE LRPO WAS SEPARATED INTO SATURATED AND AROMATIC FRACTIONS. WHOLE LRPO AND VARIOUS FRACTIONS WERE TESTED FOR MUTAGENIC ACTIVITY IN THE SALMONELLA ASSAY AND FOR CARCINOGENIC INITIATING AND PROMOTING ACTIVITY. THERE WAS NO EVIDENCE THAT ANY OF THE SAMPLES EXAMINED WERE MUTAGENIC IN BACTERIA OR CARCINOGENIC INITIATING AGENTS IN MOUSE SKIN. THUS NO SUPPORT WAS PROVIDED FOR THE HYPOTHESIS THAT THE COMPLETE TUMORIGENIC ACTIVITY OF LRPO WAS IN ANY WAY RELATED TO THE PRESENCE OF LOW LEVELS OF PAHS OR TO AN INTERACTION BETWEEN INITIATING AND PROMOTING CONSTITUENTS. THERE WAS EVIDENCE THAT LRPO WAS A WEAK PROMOTER OF DIMETHYLBENZANTHRACENE (DMBA)-INITIATED MOUSE SKIN. IT WAS ALSO FOUND THAT REPEATED APPLICATION OF LRPO PRODUCED CHRONIC IRRITATION AND HYPERPLASIA, AND THIS MAY HAVE BEEN RESPONSIBLE FOR THE PROMOTIONAL EFFECTS. BASED ON THESE DATA, IT SEEMED LIKELY THAT THE COMPLETE CARCINOGENIC ACTIVITY OF THIS CLASS OF PRODUCTS IS ALSO THE RESULT OF AN EPIGENETIC PROCESS RELATED TO SKIN IRRITATION. 1989 5 835 26 CHEMICAL CARCINOGEN MECHANISMS OF ACTION AND IMPLICATIONS FOR TESTING METHODOLOGY. CHEMICAL CARCINOGENS ARE OF TWO DISTINCT TYPES, DNA-REACTIVE AND EPIGENETIC. TESTING METHODOLOGY CAN BE DIRECTED TOWARD DETECTING EFFECTS OF BOTH TYPES OF CARCINOGEN. CARCINOGENS OF THE DNA-REACTIVE TYPE ARE DEFINED BY THE FORMATION OF COVALENTLY BOUND DNA ADDUCTS. THESE CHEMICALS HAVE STRUCTURES THAT YIELD ELECTROPHILIC REACTANTS EITHER DIRECTLY OR AFTER BIOACTIVATION. THESE AGENTS CAUSE GENOMIC ALTERATION IN THE STRUCTURE OR FUNCTION OF DNA IN THE TARGET CELL. IN ADDITION, THESE COMPOUNDS CAN EXERT OTHER CELLULAR AND TISSUE EPIGENETIC EFFECTS, SUCH AS CELL PROLIFERATION AND GROWTH PROMOTION. CARCINOGENS OF THE EPIGENETIC (PARAGENETIC) TYPE, IN CONTRAST, DO NOT REACT WITH DNA, BUT RATHER DISPLAY CELLULAR EFFECTS SUCH AS NEOPLASM GROWTH PROMOTION, CYTOTOXICITY, INHIBITION OF TISSUE GROWTH REGULATION, PEROXISOME PROLIFERATION, ENDOCRINE MODIFICATION, IMMUNOSUPPRESSION AND/OR SUSTAINED TISSUE ISCHEMIA THAT CAN BE THE BASIS FOR INCREASES IN NEOPLASIA. THEIR CHEMICAL STRUCTURE IS SUCH THAT THEY DO NOT GIVE RISE TO A REACTIVE ELECTROPHILE. THE TESTING METHODOLOGIES TO IDENTIFY EITHER TYPE FOLLOW A DECISION POINT APPROACH DESIGNED TO IDENTIFY POTENTIAL CARCINOGENICITY AND YIELD MECHANISTIC INFORMATION ON THE PRODUCTION OF EFFECTS THAT UNDERLIE CARCINOGENICITY. IT HAS 5 STAGES FOCUSING ON THE CHEMICAL STRUCTURE, DNA-REACTIVITY, EPIGENETIC EFFECTS, LIMITED BIOASSAYS AND FINALLY THE APPLICATION OF THE ACCELERATED BIOASSAY (ABA). ABA REQUIRES 40 WEEKS AND APPLIES THE USE OF SENSITIVE MARKERS FOR INDUCTION OF NEOPLASIA IN COMPARISON TO POSITIVE CONTROL COMPOUNDS FOR IMPORTANT ORGANS IN HUMAN CARCINOGENESIS. IT ENABLES DATA ACQUISITION OF THE ENTIRE CARCINOGENIC PROCESS DIRECTED TOWARD DEVELOPING MECHANISTIC INFORMATION. THE ABA HAS THE POTENTIAL TO REPLACE THE CHRONIC BIOASSAY IN RODENTS IN SOME CIRCUMSTANCES AND CAN SERVE AS AN ALTERNATIVE TO A CHRONIC BIOASSAY IN A SECOND SPECIES. 1996 6 495 29 ASSESSMENT OF THE HEALTH EFFECTS OF TRICHLOROETHYLENE. THE EPIDEMIOLOGICAL STUDIES PERFORMED THUS FAR HAVE PRESENTED ONLY LIMITED EVIDENCE FOR THE CARCINOGENICITY OF TRICHLOROETHYLENE (TRI) TO HUMANS. HOWEVER, THESE STUDIES HAD DRAWBACKS SUCH AS INSUFFICIENT SIZE OF COHORT, SHORT OBSERVATION PERIOD, AND INADEQUATE TRI EXPOSURE ASSESSMENT; THEREFORE, NO CONCRETE CONCLUSION HAS BEEN REACHED CONCERNING TRI CARCINOGENICITY TO HUMANS. DESPITE THE LIMITED EPIDEMIOLOGICAL EVIDENCE AS TO THE CARCINOGENICITY OF TRI, THE INTERNATIONAL AGENCY FOR RESEARCH ON CANCER (IARC) HAS CHANGED THE CARCINOGENICITY CLASSIFICATION OF TRI FROM GROUP 3 (NOT CLASSIFIABLE AS TO CARCINOGENICITY TO HUMANS) TO GROUP 2A (PROBABLY CARCINOGENIC TO HUMANS). IN REGARD TO THE NEW CLASSIFICATION BY THE IARC, THE COMMITTEE FOR OCCUPATIONAL EXPOSURE LIMITS OF THE JAPAN SOCIETY FOR OCCUPATIONAL HEALTH HAS MADE A PROPOSAL THAT IT IS TOO EARLY TO CLASSIFY THE CARCINOGENICITY OF TRI AS GROUP 2A AND THAT IT IS PROPER TO PROMOTE EXPOSURE CONTROL WITH THE CARCINOGENICITY BEING CLASSIFIED AS 2B FOR THE MOMENT. THERE ARE SPECIES DIFFERENCES IN TRI CARCINOGENICITY, PARTICULARLY BETWEEN RATS AND MICE. ALTHOUGH EXPERIMENTAL STUDIES HAVE FOUND NO EVIDENCE THAT TRI INDUCES LIVER CANCER IN RATS, THERE IS AMPLE EVIDENCE THAT TRI PROMOTES THE DEVELOPMENT OF LIVER CANCER IN MICE, PARTICULARLY IN B6C3F1 MICE. THE CARCINOGENICITY OF TRI IN THIS STRAIN OF MICE MAY BE BASED ON AN EPIGENETIC MECHANISM RATHER ON A GENOTOXIC MECHANISM AND THE LIVER CANCER MAY BE INDUCED ONLY AFTER TRI HAS BEEN INHALED FOR A LONG PERIOD OF TIME AT CONCENTRATIONS HIGH ENOUGH TO CAUSE CYTOTOXICITY. CONVERSELY, WITH NO REPORTS SHOWING TRI-INDUCED RENAL TUMORS IN MICE, THE POSSIBILITY HAS BEEN SUGGESTED THAT THIS CHEMICAL INDUCES SUCH TUMORS IN MALE RATS. THE SPECIES DIFFERENCES ARE MAINLY ACCOUNTED FOR BY DIFFERENCES IN THE METABOLISM OF TRI BETWEEN RATS AND MICE. FROM A GENERAL SURVEY OF THE LITERATURE, IT CAN BE CONCLUDED THAT TRI ITSELF IS NOT MUTAGENIC. HOWEVER, THE CONJUGATION OF TRI WITH GLUTATHIONE (GSH), A MINOR PATHWAY OF TRI METABOLISM, RESULTS IN MUTAGENIC METABOLITES IN THE KIDNEY OF RATS. THE ACUTE TOXICITY OF TRI IS NEUROTOXICITY BASED ON ITS ANESTHETIC ACTION. AN EXPOSURE TO EXTREMELY HIGH LEVELS OF TRI MAY CAUSE THE LIVER AND KIDNEY DISORDERS. REPEATED EXPOSURES TO HIGH LEVELS OF TRI MAY RESULT IN NEURO-, HEPATO-, AND/OR NEPHROTOXICITY. THE MAIN SYMPTOMS APPEARING AFTER CHRONIC EXPOSURE AT LOW LEVELS ARE NEUROLOGICAL CHANGES REPRESENTED BY SUBJECTIVE SYMPTOMS RELATING TO CENTRAL AND AUTONOMIC NERVOUS SYSTEMS, OR BY A LOWERED CONDUCTION VELOCITY OF THE NERVES OR A PROLONGED LATENCY OF THE NERVE RESPONSES. FOR THE PRESENT, IT IS REASONABLE TO USE THE NEUROLOGICAL FINDINGS FOR ESTABLISHING THE REFERENCE VALUES OF TRI FOR BOTH WORK AND GENERAL ENVIRONMENTS. A VALUE OF 25 PPM (135 MG/M3) IS PROPOSED AS A REFERENCE VALUE FOR WORK ENVIRONMENTS, AND 25-50 PPB (135-270 MICROGRAMS/M3) FOR THE GENERAL ENVIRONMENT (1/1,000 OF THE VALUE FOR WORK ENVIRONMENT). 1997 7 3847 19 IS CHRONIC LONG-TERM INHIBITION OF GASTRIC SECRETION REALLY DANGEROUS? POWERFUL GASTRIC SECRETION INHIBITORS PRODUCE CANCER IN THEIR TARGET ORGAN, THE STOMACH, IN EXPERIMENTAL ANIMALS. THE POSSIBLE MECHANISMS OF THE CARCINOGENIC EFFECT ARE DISCUSSED UNDER THE HEADINGS OF THE POTENTIAL NOXIOUS CHANGE IN THE GASTRIC LUMINAL CONTENTS, AS IS THE POSSIBILITY THAT THE DRUGS ACT AS EPIGENETIC OR GENOTOXIC CARCINOGENS. WHATEVER THE MECHANISMS OF THE DRUG-INDUCED CARCINOGENESIS, IT IS CLEAR THAT THERE IS A TOXICOLOGIC HAZARD, WHICH MUST BE ASSESSED RATIONALLY AND NOT BY MEANS OF SOPHISTRY. UNTIL THE DANGERS POSED BY POWERFUL GASTRIC SECRETORY INHIBITORS TO MAN HAVE BEEN BETTER EVALUATED, THESE DRUGS MUST NOT BE USED FOR TREATMENT OTHER THAN OF PATIENTS WITH GASTRINOMAS. 1988 8 3934 35 LIVER TUMOR INDUCTION. THE SIGNIFICANCE OF THE DEVELOPMENT OF NODULAR LIVER LESIONS IN RODENTS FOLLOWING THE ADMINISTRATION OF TEST AGENTS RAISES SEVERAL QUESTIONS WHICH COULD BE PLACED IN ONE OF TWO GENERAL CATEGORIES: DIAGNOSTIC AND INTERPRETATIONAL. FROM A DIAGNOSTIC POINT OF VIEW, THE PROPER CLASSIFICATION OF LIVER TUMORS INTO A BENIGN AND MALIGNANT CATEGORY HAS TO BE BASED ON THE DIRECT CORRELATION BETWEEN THE MORPHOLOGY AND THE BIOLOGIC BEHAVIOR OF THE LESIONS. THEREFORE, EXTREME CARE SHOULD BE TAKEN TO SEPARATE THE MALIGNANT TUMORS FROM THE BENIGN AND THE BENIGN NEOPLASIA FROM THE HYPERPLASIA. THE SUBSTITUTION OF THE TERM "NEOPLASTIC NODULE" FOR HYPERPLASTIC NODULE IN RATS IS MISLEADING. MOST OF THESE NODULES, WHEN INDUCED UNDER SPECIAL EXPERIMENTAL CONDITIONS, MAY REGRESS OR REMODEL AND THUS THEY ARE NOT NEOPLASTIC IN NATURE. CHRONIC CARCINOGENICITY BIOASSAYS SHOULD INCLUDE "STOP" TYPE OF TREATMENT LEAVING ENOUGH OF THE OBSERVATIONAL TIME TO ESTABLISH THE FATE OF INDUCED NODULAR LESIONS. THE INDUCTION OF HISTOCHEMICALLY CHANGED FOCI CAN SERVE ONLY AS AN INDICATION OF POTENTIAL HEPATOCARCINOGENICITY AND SHOULD NOT BE EQUATED WITH THE INDUCTION OF BONA FIDE CANCER. THE BIOLOGIC INTERPRETATION OF NODULAR LIVER LESIONS, ESPECIALLY IN MICE, NEEDS FURTHER SCRUTINY BECAUSE THESE LESIONS HAVE A TENDENCY TO DEVELOP SPONTANEOUSLY WITH HIGH INCIDENCE IN SOME STRAINS. THIS CHARACTERISTIC THEN RAISES THE QUESTION AS TO THE MECHANISM BY WHICH VARIOUS AGENTS AUGMENT AND/OR ACCELERATE THE DEVELOPMENT OF SUCH TUMORS. IS THIS ACTION PRIMARILY PROMOTING OR INITIATING IN NATURE OR DOES IT REPRESENT THE INDUCTION OF TUMORS DE NOVO? THE ANSWER TO THIS DILEMMA MAY HAVE A DECISIVE BEARING ON CARCINOGENIC RISK ASSESSMENT AND THE TYPE OF REGULATORY ACTION, SINCE THE PROMOTING AGENTS POSSESS A THRESHOLD EFFECT AND THE PROMOTED CHANGES MAY REGRESS FOLLOWING WITHDRAWAL OF TREATMENT. THE INTERPRETATION OF HEPATOCARCINOGENESIS IS FURTHER COMPLICATED BY THE FACT THAT SEVERAL FACTORS, SUCH AS SEX HORMONAL ENVIRONMENT, INCREASED MITOTIC ACTIVITY FOLLOWING AN EXCESSIVE LOSS OF PARENCHYMAL CELLS, DEGREE OF CALORIC INTAKE, ENZYMATIC COMPLEMENT, AND ANIMALS' AGE AT THE TIME OF THE EXPOSURE TO A TEST AGENT, MAY INFLUENCE THE OUTCOME OF LIVER TUMOR DEVELOPMENT BY MODULATING "INITIATION" AND/OR "PROMOTION" OF CARCINOGENESIS. BROAD FLUCTUATION IN THE HISTORIC INCIDENCE OF LIVER TUMORS FURTHER COMPOUNDS THE COMPLEXITY OF THE PROPER BIOASSAY INTERPRETATION. THE SPECIFICALLY DESIGNED EXPERIMENTS MAY HAVE THE OBJECTIVE TO EXPLORE PREDOMINANTLY THE INITIATING OR PROMOTING EFFECTS OF THE AGENT. SUCH PROTOCOLS SHOULD BE USED WHENEVER NECESSARY TO DIFFERENTIATE BETWEEN THESE TWO MECHANISMS OF ACTION. IN THE CAUCASIANS, THE "SPONTANEOUS" DEVELOPMENT OF THE PRIMARY HEPATOCELLULAR TUMORS IS RARE. THE MAJORITY OF THESE TUMORS ARE MALIGNANT AND RAPIDLY FATAL. ACCORDING TO SOME HUMAN PATHOLOGISTS, THE BENIGN VARIETY OF LIVER TUMORS IS RARE AND IT DOES NOT REPRESENT NECESSARILY A PREMALIGNANT STAGE IN TUMOR DEVELOPMENT. CARCINOMA OF THE LIVER MAY OCCUR IN INFANCY, ESPECIALLY IN MALES BEFORE THE AGE OF 2 YEARS. THIS SUGGESTS A GENETIC CAUSATION OR CARCINOGENIC EXPOSURE IN UTERO. ONE OF THE GEOGRAPHIC FACTORS WHICH SIGNIFICANTLY ENHANCES THE INCIDENCE OF HEPATOCELLULAR CARCINOMA IN HUMANS IS EXPOSURE TO AFLATOXIN B(1) WHICH IS APPARENTLY POTENTIATED BY CONCURRENT LIVER CIRRHOSIS. BECAUSE MANY MORE AGENTS HAVE BEEN FOUND TO BE HEPATOCARCINOGENIC IN MICE AND RATS THAN IN MEN, A QUESTION ARISES AS TO THE DIRECT RELEVANCE OF RODENT STUDIES TO HUMANS. A BALANCED ASSESSMENT OF THE CARCINOGENICITY OF THE AGENT COULD ONLY BE REACHED IN CONSIDERING BOTH THE PHARMACOKINETICS AND THE DEVELOPMENT OF MALIGNANT NEOPLASIA IN OTHER ORGANS. IN THE CASE OF POSITIVE CARCINOGENICITY ASSESSMENT, THE OUTCOME OF THE MUTAGENICITY BIOASSAYS CAN SUGGEST GENIC (GENOTOXIC) OR PARAGENIC (EPIGENETIC) MODE OF ACTION IN MAMMALIAN SYSTEMS. 1982 9 5493 13 REVIEW OF IN VITRO TEST SYSTEMS USING DNA DAMAGE AND REPAIR FOR SCREENING OF CHEMICAL CARCINOGENS. CHEMICAL CARCINOGENS ARE MECHANISTICALLY CLASSIFIED AS GENOTOXIC WHICH INTERACT DIRECTLY WITH DNA, AND EPIGENETIC WHICH CAUSE CHRONIC TISSUE INJURY, HORMONAL IMBALANCE, AND PROMOTIONAL EFFECTS. THIS REVIEW EVALUATES IN VITRO TESTS FOR THEIR CONTRIBUTION TO A BATTERY FOR IDENTIFYING GENOTOXIC CHEMICAL CARCINOGENS. IN ADDITION TO BACTERIAL MUTAGENIC ASSAYS, NONSPECIFIC DNA DAMAGE/REPAIR TESTS ARE RECOMMENDED FOR SCREENING CHEMICALS, IN PARTICULAR THE HEPATOCYTE PRIMARY CULTURE/DNA REPAIR TEST. 1979 10 4819 22 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 11 3623 29 IN VIVO COMET ASSAY ON ISOLATED KIDNEY CELLS TO DISTINGUISH GENOTOXIC CARCINOGENS FROM EPIGENETIC CARCINOGENS OR CYTOTOXIC COMPOUNDS. THE OBJECTIVE OF THIS STUDY WAS TO DETERMINE THE ABILITY OF THE ALKALINE IN VIVO COMET ASSAY (PH>13) TO DISTINGUISH GENOTOXIC CARCINOGENS FROM EPIGENETIC CARCINOGENS WHEN PERFORMED ON FRESHLY ISOLATED KIDNEY CELLS AND TO DETERMINE THE POSSIBLE INTERFERENCE OF CYTOTOXICITY BY ASSESSING DNA DAMAGE INDUCED BY RENAL GENOTOXIC, EPIGENETIC OR TOXIC COMPOUNDS AFTER ENZYMATIC ISOLATION OF KIDNEY CELLS FROM OFA SPRAGUE-DAWLEY MALE RATS. THE ABILITY OF THE COMET ASSAY TO DISTINGUISH (1) GENOTOXICITY VERSUS CYTOTOXICITY AND (2) GENOTOXIC VERSUS NON-GENOTOXIC (EPIGENETIC) CARCINOGENS, WAS THUS INVESTIGATED BY STUDYING FIVE KNOWN GENOTOXIC RENAL CARCINOGENS ACTING THROUGH DIVERSE MECHANISMS OF ACTION, I.E. STREPTOZOTOCIN, ARISTOLOCHIC ACIDS, 2-NITROANISOLE, POTASSIUM BROMATE AND CISPLATIN, TWO RODENT RENAL EPIGENETIC CARCINOGENS: D-LIMONENE AND CICLOSPORINE AND TWO NEPHROTOXIC COMPOUNDS: STREPTOMYCIN AND INDOMETHACIN. ANIMALS WERE TREATED ONCE WITH THE TEST COMPOUND BY THE APPROPRIATE ROUTE OF ADMINISTRATION AND GENOTOXIC EFFECTS WERE MEASURED AT THE TWO SAMPLING TIMES OF 3-6 AND 22-26H AFTER TREATMENT. REGARDING THE TISSUE PROCESSING, THE LIMITED BACKGROUND LEVEL OF DNA MIGRATION OBSERVED IN THE NEGATIVE CONTROL GROUPS THROUGHOUT ALL EXPERIMENTS DEMONSTRATED THAT THE ENZYMATIC ISOLATION METHOD IMPLEMENTED IN THE CURRENT STUDY IS APPROPRIATE. ON THE OTHER HAND, STREPTOZOTOCIN, 20MG/KG, USED AS POSITIVE REFERENCE CONTROL CONCURRENTLY TO EACH ASSAY, CAUSED A CLEAR INCREASE IN THE MEAN OLIVE TAIL MOMENT MEDIAN VALUE, WHICH ALLOWS VALIDATING THE CURRENT METHODOLOGY. UNDER THESE EXPERIMENTAL CONDITIONS, THE IN VIVO RODENT COMET ASSAY DEMONSTRATED GOOD SENSITIVITY AND GOOD SPECIFICITY: ALL THE FIVE RENAL GENOTOXIC CARCINOGENS WERE CLEARLY DETECTED IN AT LEAST ONE EXPRESSION PERIOD EITHER DIRECTLY OR INDIRECTLY, AS IN THE CASE OF CISPLATIN: FOR THIS CROSS-LINKING AGENT, THE SIGNIFICANT DECREASE IN DNA MIGRATION OBSERVED UNDER STANDARD ELECTROPHORESIS CONDITIONS WAS CLEARLY AMPLIFIED WHEN THE DURATION OF ELECTROPHORESIS WAS INCREASED UP TO 40MIN. IN CONTRAST, EPIGENETIC AND NEPHROTOXIC COMPOUNDS FAILED TO INDUCE ANY SIGNIFCANT INCREASE IN DNA MIGRATION. IN CONCLUSION, THE IN VIVO RODENT COMET ASSAY PERFORMED ON ISOLATED KIDNEY CELLS COULD BE USED AS A TOOL TO INVESTIGATE THE GENOTOXIC POTENTIAL OF A TEST COMPOUND IF NEOPLASIC/PRENEOPLASIC CHANGES OCCUR AFTER SUBCHRONIC OR CHRONIC TREATMENTS, IN ORDER TO DETERMINE THE ROLE OF GENOTOXICITY IN TUMOR INDUCTION. MOREOVER, THE EPIGENETIC CARCINOGENS AND CYTOTOXIC COMPOUNDS DISPLAYED CLEARLY NEGATIVE RESPONSES IN THIS STUDY. THESE RESULTS ALLOW EXCLUDING A DNA DIRECT-ACTING MECHANISM OF ACTION AND CAN THUS SUGGEST THAT A THRESHOLD EXISTS. THEREFORE, THE CURRENT IN VIVO RODENT COMET ASSAY COULD CONTRIBUTE TO ELUCIDATE AN EPIGENETIC MECHANISM AND THUS, TO UNDERTAKE A RISK ASSESSMENT ASSOCIATED WITH HUMAN USE, DEPENDING ON THE EXPOSURE LEVEL. 2007 12 745 34 CANNABIS ALTERS EPIGENETIC INTEGRITY AND ENDOCANNABINOID SIGNALLING IN THE HUMAN FOLLICULAR NICHE. STUDY QUESTION: DO PHYTOCANNABINOIDS (PCS) AFFECT FOLLICULAR ENDOCANNABINOID SIGNALLING AND THE EPIGENOME IN THE SURROUNDING GRANULOSA CELLS (GCS)? SUMMARY ANSWER: EXPOSURE TO PCS INCREASES THE EXPRESSION OF ENDOCANNABINOID RECEPTORS AND REDUCES DNA METHYLATION ENZYME EXPRESSION AND GLOBAL DNA METHYLATION IN NAIVE GCS. WHAT IS KNOWN ALREADY: CANNABIS PLANT DERIVATIVES, KNOWN AS PCS, ARE USED FOR MEDICINAL AND RECREATIONAL PURPOSES. THE MAIN PC, TETRAHYDROCANNABINOL (THC), IS THE THIRD MOST COMMONLY USED SUBSTANCE BY WOMEN OF CHILDBEARING AGE, HENCE KNOWLEDGE OF THE EFFECT IT HAS ON REPRODUCTION IS OF UTMOST IMPORTANCE. THC EXERTS ITS EFFECTS VIA RECEPTORS OF THE ENDOCANNABINOID SYSTEM (ECS) AND CAN INTERFERE WITH FOLLICULOGENESIS, OOCYTE DEVELOPMENT AND OVULATION. ENDOCANNABINOIDS HAVE BEEN MEASURED IN FOLLICULAR FLUID (FF) OBTAINED DURING OOCYTE RETRIEVAL AND ARE IMPLICATED IN CONTROLLING FOLLICULOGENESIS. IT HAS BEEN ESTABLISHED THAT IN THE PLACENTA, PCS DISRUPT ENDOCANNABINOID HOMEOSTASIS VIA IMPAIRMENT OF THE SYNTHETIC AND DEGRADING ENZYMES, LEADING TO A NET INCREASE OF ENDOCANNABINOID LEVELS. FINALLY, PREVIOUS STUDIES HAVE SHOWN THAT THC ALTERS METHYLATION AND HISTONE MODIFICATIONS IN SPERM, BRAIN AND BLOOD CELLS. STUDY DESIGN, SIZE, DURATION: THIS STUDY INCLUDED AN IN VIVO COHORT ASSESSMENT OF CANNABIS EXPOSURE AND ITS EFFECTS ON THE FOLLICLE AND IN VITRO ASSAYS CONDUCTED TO VALIDATE THE IN VIVO FINDINGS AND TO EXPLORE POSSIBLE MECHANISMS OF ACTION. PARTICIPANTS/MATERIALS, SETTING, METHODS: A TOTAL OF 318 FF SAMPLES, FROM 261 PATIENTS UNDERGOING IVF TREATMENT AT A PRIVATE FERTILITY CLINIC WHO CONSENTED FOR BIOBANKING BIOLOGICAL WASTE MATERIAL BETWEEN JANUARY 2018 AND JULY 2019, WERE INCLUDED IN THIS STUDY. CONCENTRATIONS OF PCS AND ENDOCANNABINOIDS WERE ASSESSED IN FF BY LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY (LC-MS/MS). EXPOSURE TO PCS WAS DETERMINED BASED ON THESE MEASURED LEVELS. LEVELS OF BOTH ENDOCANNABINOID RECEPTORS (CB1R, CB2R) AND THE DE NOVO DNA METHYLATING ENZYME, DNMT3B, IN GCS WERE ASSESSED BY FLOW CYTOMETRY BOTH IN VITRO AND IN VIVO AND GLOBAL DNA METHYLATION WAS ASSESSED IN VITRO BY ELISA. IN VIVO EFFECTS WERE ASSESSED BY COMPARING SAMPLES POSITIVE FOR AT LEAST ONE PC, WITH SAMPLES NEGATIVE FOR ALL MEASURED PCS. IN VITRO EFFECTS WERE DETERMINED IN NAIVE GCS, OBTAINED CONCURRENTLY WITH FF SAMPLES THAT HAD TESTED NEGATIVE FOR ALL PCS. THESE GCS WERE TREATED WITH DIFFERENT COMBINATIONS OF THE MAIN THREE PCS. MAIN RESULTS AND THE ROLE OF CHANCE: OVERALL, 17 PATIENTS (6.4%) WERE POSITIVE FOR CANNABIS CONSUMPTION. FURTHERMORE, THE PREVALENCE OF CANNABIS POSITIVITY IN THE FF INCREASED FROM 4% OF THE TESTED SAMPLES THAT WERE COLLECTED PRIOR TO NATIONAL LEGALISATION IN OCTOBER 2018 TO 12% OF THOSE COLLECTED FOLLOWING LEGALISATION. OF NOTE, 59% OF PATIENTS WHO TESTED POSITIVE FOR PCS (10 OF 17) REPORTED PREVIOUS OR ONGOING EXPOSURE TO CANNABIS UPON THEIR INITIAL INTAKE. ENDOCANNABINOID LEVELS WERE NOT AFFECTED BY THE PRESENCE OF PCS. CB2R WAS MORE PREVALENT THAN CB1R IN GCS AND ITS EXPRESSION INCREASED FOLLOWING ACUTE AND CHRONIC IN VITRO EXPOSURE TO PCS. THE EXPRESSION OF DNMT3B AND GLOBAL METHYLATION DECREASED FOLLOWING EXPOSURE, SUGGESTING THAT CANNABIS MAY AFFECT THE EPIGENOME IN THE FOLLICULAR NICHE. THE ACUTE CHANGES WERE SUSTAINED THROUGHOUT CHRONIC TREATMENT. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: OUR STUDY IS LIMITED BY LACK OF DETAILS REGARDING MODE, FREQUENCY AND TIMING OF PC CONSUMPTION. MOREOVER, WE WERE NOT ABLE TO ADEQUATELY ASSESS THE EFFECT OF PCS ON IMMEDIATE OR LONG-TERM CLINICAL OUTCOMES, DUE TO THE SMALL SAMPLE SIZE AND THE LACK OF FOLLOW UP. FUTURE, LARGE-SCALE STUDIES SHOULD FOCUS ON ASSESS THE CLINICAL IMPLICATIONS OF CANNABIS EXPOSURE, VALIDATE OUR FINDINGS, AND DETERMINE TO WHAT EXTENT CANNABIS AFFECTS THE EPIGENOME OVARIAN FOLLICLE AND THE DEVELOPING OOCYTE. WIDER IMPLICATIONS OF THE FINDINGS: TO OUR KNOWLEDGE, THIS IS THE FIRST STUDY MEASURING PCS IN FF BY LC-MS/MS. WE SHOW THAT CONSUMING CANNABIS ALTERS THE ECS IN THE DEVELOPING FOLLICLE, AND DIRECTLY AFFECTS DNMT EXPRESSION AND GLOBAL DNA METHYLATION LEVELS. CANNABIS LEGALISATION AND USE IS INCREASING WORLDWIDE, THEREFORE FURTHER UNDERSTANDING ITS ROLE IN FEMALE FERTILITY AND FOLLICULOGENESIS IS CRITICAL. STUDY FUNDING/COMPETING INTEREST(S): ALL FUNDING WAS PROVIDED BY CREATE FERTILITY CENTRE THROUGH THE REINVESTMENT OF CLINICAL EARNINGS. THE AUTHORS DECLARE NO COMPETING INTERESTS. 2021 13 5113 19 POPULATION-LEVEL IMPACTS OF PESTICIDE-INDUCED CHRONIC EFFECTS ON INDIVIDUALS DEPEND MORE ON ECOLOGY THAN TOXICOLOGY. THE CURRENT METHOD FOR ASSESSING LONG-TERM RISK OF PESTICIDES TO MAMMALS IN THE EU IS BASED ON THE INDIVIDUAL RATHER THAN THE POPULATION-LEVEL AND LACKS ECOLOGICAL REALISM. HENCE THERE IS LITTLE POSSIBILITY FOR REGULATORY AUTHORITIES TO INCREASE ECOLOGICAL REALISM AND UNDERSTANDING OF RISKS AT THE POPULATION-LEVEL. HERE WE DEMONSTRATE HOW, USING ABM MODELLING, ASSESSMENTS AT THE POPULATION-LEVEL CAN BE OBTAINED EVEN FOR A PESTICIDE WITH COMPLEX LONG-TERM EFFECTS SUCH AS EPIGENETIC TRANSMISSION OF REPRODUCTIVE DEPRESSION. BY OBJECTIVELY FITTING NONLINEAR MODELS TO THE SIMULATION OUTPUTS IT WAS POSSIBLE TO COMPARE POPULATION DEPRESSION AND RECOVERY RATES FOR A RANGE OF SCENARIOS IN WHICH TOXICITY AND EXPOSURE FACTORS WERE VARIED. THE SYSTEM WAS DIFFERENTIALLY SENSITIVE TO THE VARIOUS FACTORS, BUT VOLE ECOLOGY AND BEHAVIOUR WERE AT LEAST AS IMPORTANT PREDICTORS OF POPULATION-LEVEL EFFECTS AS TOXICOLOGY. THIS EMPHASISES THE NEED FOR GREATER FOCUS ON ANIMAL ECOLOGY IN RISK ASSESSMENTS. 2009 14 3037 27 GENOME AND METHYLOME VARIATION IN HELICOBACTER PYLORI WITH A CAG PATHOGENICITY ISLAND DURING EARLY STAGES OF HUMAN INFECTION. BACKGROUND & AIMS: HELICOBACTER PYLORI IS REMARKABLE FOR ITS GENETIC VARIATION; YET, LITTLE IS KNOWN ABOUT ITS GENETIC CHANGES DURING EARLY STAGES OF HUMAN INFECTION, AS THE BACTERIA ADAPT TO THEIR NEW ENVIRONMENT. WE ANALYZED GENOME AND METHYLOME VARIATIONS IN A FULLY VIRULENT STRAIN OF H PYLORI DURING EXPERIMENTAL INFECTION. METHODS: WE PERFORMED A RANDOMIZED PHASE I/II, OBSERVER-BLIND, PLACEBO-CONTROLLED STUDY OF 12 HEALTHY, H PYLORI-NEGATIVE ADULTS IN GERMANY FROM OCTOBER 2008 THROUGH MARCH 2010. THE VOLUNTEERS WERE GIVEN A PROPHYLACTIC VACCINE CANDIDATE (N = 7) OR PLACEBO (N = 5) AND THEN CHALLENGED WITH H PYLORI STRAIN BCM-300. BIOPSY SAMPLES WERE COLLECTED AND H PYLORI WERE ISOLATED. GENOMES OF THE CHALLENGE STRAIN AND 12 REISOLATES, OBTAINED 12 WEEKS AFTER (OR IN 1 CASE, 62 WEEKS AFTER) INFECTION WERE SEQUENCED BY SINGLE-MOLECULE, REAL-TIME TECHNOLOGY, WHICH, IN PARALLEL, PERMITTED DETERMINATION OF GENOME-WIDE METHYLATION PATTERNS FOR ALL STRAINS. FUNCTIONAL EFFECTS OF GENETIC CHANGES OBSERVED IN H PYLORI STRAINS DURING HUMAN INFECTION WERE ASSESSED BY MEASURING RELEASE OF INTERLEUKIN 8 FROM AGS CELLS (TO DETECT CAG PATHOGENICITY ISLAND FUNCTION), NEUTRAL RED UPTAKE (TO DETECT VACUOLATING CYTOTOXIN ACTIVITY), AND ADHESION ASSAYS. RESULTS: THE OBSERVED MUTATION RATE WAS IN AGREEMENT WITH RATES PREVIOUSLY DETERMINED FROM PATIENTS WITH CHRONIC H PYLORI INFECTIONS, WITHOUT EVIDENCE OF A MUTATION BURST. A LOSS OF CAG PATHOGENICITY ISLAND FUNCTION WAS OBSERVED IN 3 REISOLATES. IN ADDITION, 3 REISOLATES FROM THE VACCINE GROUP ACQUIRED MUTATIONS IN THE VACUOLATING CYTOTOXIN GENE VACA, RESULTING IN LOSS OF VACUOLIZATION ACTIVITY. WE OBSERVED INTERSTRAIN VARIATION IN METHYLOMES DUE TO PHASE VARIATION IN GENES ENCODING METHYLTRANSFERASES. CONCLUSIONS: WE ANALYZED ADAPTATION OF A FULLY VIRULENT STRAIN OF H PYLORI TO 12 DIFFERENT VOLUNTEERS TO OBTAIN A ROBUST ESTIMATE OF THE FREQUENCY OF GENETIC AND EPIGENETIC CHANGES IN THE ABSENCE OF INTERSTRAIN RECOMBINATION. OUR FINDINGS INDICATE THAT THE LARGE AMOUNT OF GENETIC VARIATION IN H PYLORI POSES A CHALLENGE TO VACCINE DEVELOPMENT. CLINICALTRIALS.GOV NO: NCT00736476. 2018 15 3803 27 INTESTINAL METAPLASIA OF THE STOMACH. A STATUS REPORT. INTESTINAL METAPLASIA IN THE STOMACH INCREASES THE RISK OF GASTRIC CANCER, AND THE INCREASED RISK IS PROPORTIONAL TO THE EXTENT OF THE METAPLASIA. THIS RISK COULD BE GENERATED BY ONE OR MORE MECHANISMS: (1) THE METAPLASTIC TISSUE IS AN EARLY STEP IN A MULTISTEP INDUCTION PROCESS; (2) THE METAPLASTIC TISSUE IS AN EPIGENETIC CHANGE THAT RAISES THE PH OF GASTRIC JUICE BY REPLACING OXYNTIC MUCOSA, FAVORING THE GROWTH OF A BACTERIA CAPABLE OF GENERATING ENDOGENOUS MUTAGENS; AND/OR (3) THE METAPLASIA IS ONLY A MARKER FOR CHRONIC GASTRITIS DUE TO H. PYLORI INFECTION OR PERNICIOUS ANEMIA. WITH THE LAST MECHANISM, THE INFLAMMATORY RESPONSE FAVORS INTRAMURAL MUTAGENESIS THAT MIGHT RESULT IN METAPLASIA OR NEOPLASIA AS INDEPENDENT EVENTS. FINDING GENE REARRANGEMENTS COMMON TO BOTH METAPLASTIC AND NEOPLASTIC TISSUE MAY ESTABLISH A DIRECT LINK BETWEEN THEM, BUT TOO FEW HAVE BEEN IDENTIFIED TO ACCOUNT FOR THE LARGE NUMBER OF STOMACH CANCERS THAT DEVELOP IN HIGH RISK POPULATIONS. HISTOCHEMICAL AND IMMUNOCHEMICAL STAINS THAT IDENTIFY ENZYMES OR MUCOSUBSTANCES MAY SUGGEST THAT METAPLASTIC EPITHELIAL CELLS RESEMBLE SMALL OR LARGE INTESTINAL CELLS, BUT THEY ARE DISTINCTLY DIFFERENT FROM BOTH. MOREOVER, THESE STAINS DO NOT INDICATE WHETHER A GIVEN CYTOLOGIC CHANGE IS GENETIC OR EPIGENETIC; THEREFORE, THEY CANNOT BE USED TO DEFINE THE RELATIONSHIP BETWEEN METAPLASIA AND NEOPLASIA. IT IS UNNECESSARY FOR PRACTICING PHYSICIANS TO AWAIT RESOLUTION OF THIS QUESTION. IT CAN BE ASSUMED THAT ANY PERSON WITH EXTENSIVE METAPLASIA IS AT HIGH RISK FOR GASTRIC CANCER AND SHOULD BE SUBJECT TO PERIODIC SCREENING. THE EXTENT OF THE METAPLASTIC PROCESS IS PROBABLY MORE IMPORTANT THAN THE METAPLASTIC SUBTYPE. 1994 16 4363 20 MIRNA AS MARKERS FOR THE DIAGNOSTIC SCREENING OF COLON CANCER. EARLY SCREENING FOR COLON CANCER (CC) ALLOWS FOR EARLY STAGE DIAGNOSIS OF THE MALIGNANCY AND POTENTIALLY REDUCES DISEASE MORTALITY AS THE CANCER IS MOST LIKELY CURABLE AT ITS EARLIEST STAGES. EARLY DETECTION WOULD BE DESIRABLE IF ACCURATE, PRACTICAL AND COST-EFFECTIVE DIAGNOSTIC MEASURES FOR THIS CANCER WERE AVAILABLE. MORTALITY AND MORBIDITY FROM CC REPRESENT A MAJOR HEALTH PROBLEM INVOLVING A MALIGNANT DISEASE THAT IS THEORETICALLY PREVENTABLE THROUGH SCREENING. CURRENT SCREENING METHODS (E.G., THE CONVENIENT AND INEXPENSIVE IMMUNOLOGICAL FECAL OCCULT BLOOD TEST, FOBTI, OBTAINED FROM PATIENTS' MEDICAL RECORDS) EITHER LACK SENSITIVITY AND REQUIRE DIETARY RESTRICTION, WHICH IMPEDES COMPLIANCE AND USE; ARE COSTLY (E.G., COLONOSCOPY), WHICH DECREASES COMPLIANCE; OR COULD RESULT IN MORTALITY. IN COMPARISON WITH THE FOBT TEST, A NON-INVASIVE SENSITIVE SCREEN FOR WHICH THERE IS NO REQUIREMENT FOR DIETARY RESTRICTION WOULD BE A MORE CONVENIENT TEST. COLORECTAL CANCER IS THE ONLY CANCER FOR WHICH COLONOSCOPY IS RECOMMENDED AS A SCREENING METHOD. ALTHOUGH COLONOSCOPY IS A RELIABLE SCREENING TOOL, THE INVASIVE NATURE, ABDOMINAL PAIN, POTENTIAL COMPLICATIONS AND HIGH COST HAVE HAMPERED THE APPLICATION OF THIS PROCEDURE WORLDWIDE. A SCREENING APPROACH USING THE STABLE MIRNA MOLECULES, WHICH ARE RELATIVELY NON-DEGRADABLE WHEN EXTRACTED FROM NON-INVASIVE STOOL AND SEMI-INVASIVE BLOOD SAMPLES BY COMMERCIALLY AVAILABLE KITS AND MANIPULATED THEREAFTER, WOULD BE PREFERABLE TO A TRANSCRIPTOMIC MRNA-, A MUTATION DNA-, AN EPIGENETIC- OR A PROTEOMIC-BASED TEST. THE APPROACH USES REVERSE TRANSCRIPTASE, MODIFIED REAL-TIME QUANTITATIVE PCR. ALTHOUGH EXOSOMAL RNA WOULD BE MISSED, USING A RESTRICTED EXTRACTION OF TOTAL RNA FROM STOOL OR BLOOD, A PARALLEL TEST COULD ALSO BE CARRIED OUT ON RNA OBTAINED FROM STOOL OR PLASMA SAMPLES, AND APPROPRIATE CORRECTIONS FOR EXSOSOMAL LOSS CAN BE MADE FOR ACCURATE AND QUANTITATIVE TEST RESULT. EVENTUALLY, A CHIP CAN BE DEVELOPED TO FACILITATE DIAGNOSIS, AS HAS BEEN DONE FOR THE QUANTIFICATION OF GENETICALLY MODIFIED ORGANISMS IN FOODS. THE GOLD STANDARD TO WHICH THE MOLECULAR MIRNA TEST IS COMPARED IS COLONOSCOPY, WHICH CAN BE OBTAINED FROM PATIENTS' MEDICAL RECORDS. IF PERFORMANCE CRITERIA ARE MET, AS DETAILED HEREIN, A MIRNA TEST IN HUMAN STOOL OR BLOOD SAMPLES BASED ON HIGH-THROUGHPUT AUTOMATED TECHNOLOGIES AND QUANTITATIVE EXPRESSION MEASUREMENTS COMMONLY USED IN THE DIAGNOSTIC CLINICAL LABORATORY SHOULD BE ADVANCED TO THE CLINICAL SETTING, WHICH WILL MAKE A SIGNIFICANT IMPACT ON CC PREVENTION. 2014 17 1407 26 DIETARY INFLUENCES ON MUTAGENESIS--WHERE IS THIS FIELD GOING? EARLY STUDIES ON DIETARY MUTAGENESIS WERE MOSTLY OBSERVATIONAL, WITH LARGE NUMBERS OF POTENTIAL DIETARY MUTAGENS BEING IDENTIFIED FROM EVERY CONCEIVABLE DIETARY SOURCE. THESE INCLUDED KNOWN DIETARY CARCINOGENS SUCH AS AFLATOXIN B1 AND BENZO[A]PYRENE, AND HITHERTO UNRECOGNIZED DIETARY MUTAGENS, SUCH AS THE PYROLYSIS PRODUCTS FORMED DURING THE HEATING OF PROTEINACEOUS MATERIALS (HETEROCYCLIC AMINES). THE 1993 EVALUATION OF 2-AMINO-3-METHYL-3H-IMIDAZO(4,5-J)QUINOLINE AS A PROBABLE HUMAN CARCINOGEN BY THE INTERNATIONAL AGENCY FOR RESEARCH ON CANCER WAS A LANDMARK, AS THIS WAS DONE IN THE ABSENCE OF SPECIFIC HUMAN CARCINOGENICITY DATA, AND STRONGLY INFLUENCED BY MUTAGENICITY TEST DATA. IN THE 21ST CENTURY, THE FIELD HAS MOVED FROM THE IDENTIFICATION OF MORE AND MORE MUTAGENS, TO MOLECULAR EPIDEMIOLOGIC APPROACHES THAT NOT ONLY SHOW A MUTAGENIC EFFECT BUT ALSO SEEK TO LINK IT TO A DIETARY (OR ENVIRONMENTAL) CAUSE. EFFECTS OF DIET IN STIMULATING CHRONIC INFLAMMATION MAY LEAD TO REACTIVE SPECIES AND THEREBY MUTATION AS A SECONDARY CONSEQUENCE, WHILE DIETARY DEFICIENCIES AND NUTRIENT IMBALANCES MAY BE STRONG SOURCES OF MUTAGENESIS. RECOGNITION OF THE ROLES OF NUTRIENTS IN CELL SIGNALING PROCESSES AND CONTROL OF MICRORNAS SUGGEST MAJOR INFLUENCES ON GENE EXPRESSION, IN THE ABSENCE OF PERMANENT DNA CHANGES. GENOME-WIDE ASSOCIATION STUDIES HAVE HIGHLIGHTED NEW PATHWAYS SUCH AS JAK/STAT SIGNALING THAT PROFOUNDLY INFLUENCE GENOMIC INSTABILITY AND RESPONSES TO DIETARY MUTAGENS. WITH IMPROVED METHODOLOGIES FOR DNA SEQUENCING AND EPIGENETIC CHANGES, IT IS TIME TO APPLY MORE SOPHISTICATED APPROACHES TO RECOGNIZING AND PROVING THE ROLE OF DIET AS A PRIMARY MODULATOR OF MUTAGENESIS IN HUMANS. 2010 18 414 19 ANALYSIS OF PROMOTER METHYLATION IN STOOL: A NOVEL METHOD FOR THE DETECTION OF COLORECTAL CANCER. BACKGROUND & AIMS: DETECTION OF TUMOR-DERIVED DNA ALTERATIONS IN STOOL IS AN INTRIGUING NEW APPROACH WITH HIGH POTENTIAL FOR THE NONINVASIVE DETECTION OF COLORECTAL CANCER (CRC). BECAUSE OF HETEROGENEITY OF TUMORS, USUALLY MULTIPLE MARKERS DISTRIBUTED THROUGHOUT THE HUMAN GENOME NEED TO BE ANALYZED. THIS IS LABOR INTENSIVE AND DOES NOT ALLOW FOR HIGH THROUGH-PUT SCREENING. THEREFORE, MARKERS WITH HIGH SENSITIVITY AND GOOD SPECIFICITY ARE NEEDED. WE EXPLORED THE POTENTIAL OF A SINGLE EPIGENETIC MARKER IN COMPARISON WITH FECAL OCCULT BLOOD TESTING (FOBT) FOR THE DISCRIMINATION OF PATIENTS WITH CRCS AND ADENOMAS FROM THOSE WITHOUT. METHODS: METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (PCR) WAS PERFORMED TO ANALYZE HYPERMETHYLATED IN CANCER 1 (HIC1) PROMOTER METHYLATION STATUS IN A BLINDED FASHION IN STOOL SAMPLES FROM 26 PATIENTS WITH CRC, 13 WITH ADENOMA > OR =1 CM, 9 WITH HYPERPLASTIC POLYPS, 9 WITH CHRONIC INFLAMMATORY BOWEL DISEASE, AND 32 WITH ENDOSCOPICALLY NORMAL COLON. RESULTS: NINETY-SEVEN PERCENT OF THE STOOL SAMPLES CONTAINED AMPLIFIABLE DNA. FORTY-TWO PERCENT OF THE SAMPLES FROM PATIENTS WITH CRC AND 31% OF THE SAMPLES FROM PATIENTS WITH COLORECTAL ADENOMA > OR =1 CM WERE POSITIVE FOR HIC1 PROMOTER METHYLATION. NO METHYLATED HIC1 PROMOTER DNA WAS DETECTED IN THE FECAL DNA FROM PATIENTS WITH ENDOSCOPICALLY NORMAL COLON OR HYPERPLASTIC POLYPS. CONCLUSIONS: THE EPIGENETIC MARKER HIC1 PROMOTER METHYLATION CARRIES HIGH POTENTIAL FOR THE REMOTE DETECTION OF CRCS. WE POSTULATE THAT A PANEL OF MERELY A FEW GENETIC AND EPIGENETIC MARKERS WILL BE REQUIRED FOR THE HIGHLY SENSITIVE AND SPECIFIC DETECTION OF CRCS AND ADENOMAS IN FECAL SAMPLES FROM AFFECTED PATIENTS. 2005 19 5057 19 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 20 5613 26 SAFETY AND EFFICACY OF ABEXINOSTAT, A PAN-HISTONE DEACETYLASE INHIBITOR, IN NON-HODGKIN LYMPHOMA AND CHRONIC LYMPHOCYTIC LEUKEMIA: RESULTS OF A PHASE II STUDY. HISTONE DEACETYLASE INHIBITORS ARE MEMBERS OF A CLASS OF EPIGENETIC DRUGS THAT HAVE PROVEN ACTIVITY IN T-CELL MALIGNANCIES, BUT LITTLE IS KNOWN ABOUT THEIR EFFICACY IN B-CELL LYMPHOMAS. ABEXINOSTAT IS AN ORALLY AVAILABLE HYDROXAMATE-CONTAINING HISTONE DEACETYLASE INHIBITOR THAT DIFFERS FROM APPROVED INHIBITORS; ITS UNIQUE PHARMACOKINETIC PROFILE AND ORAL DOSING SCHEDULE, TWICE DAILY FOUR HOURS APART, ALLOWS FOR CONTINUOUS EXPOSURE AT CONCENTRATIONS REQUIRED TO EFFICIENTLY KILL TUMOR CELLS. IN THIS PHASE II STUDY, PATIENTS WITH RELAPSED/REFRACTORY NON-HODGKIN LYMPHOMA OR CHRONIC LYMPHOCYTIC LEUKEMIA RECEIVED ORAL ABEXINOSTAT AT 80 MG BID FOR 14 DAYS OF A 21-DAY CYCLE AND CONTINUED UNTIL PROGRESSIVE DISEASE OR UNACCEPTABLE TOXICITY. A TOTAL OF 100 PATIENTS WITH B-CELL MALIGNANCIES AND T-CELL LYMPHOMAS WERE ENROLLED BETWEEN OCTOBER 2011 AND JULY 2014. ALL PATIENTS RECEIVED AT LEAST ONE DOSE OF STUDY DRUG. PRIMARY REASONS FOR DISCONTINUATION INCLUDED PROGRESSIVE DISEASE (56%) AND ADVERSE EVENTS (25%). GRADE 3 OR OVER ADVERSE EVENTS AND ANY SERIOUS ADVERSE EVENTS WERE REPORTED IN 88% AND 73% OF PATIENTS, RESPECTIVELY. THE MOST FREQUENTLY REPORTED GRADE 3 OR OVER TREATMENT-EMERGENT RELATED ADVERSE EVENTS WERE THROMBOCYTOPENIA (80%), NEUTROPENIA (27%), AND ANEMIA (12%). AMONG THE 87 PATIENTS EVALUABLE FOR EFFICACY, OVERALL RESPONSE RATE WAS 28% (COMPLETE RESPONSE 5%), WITH HIGHEST RESPONSES OBSERVED IN PATIENTS WITH FOLLICULAR LYMPHOMA (OVERALL RESPONSE RATE 56%), T-CELL LYMPHOMA (OVERALL RESPONSE RATE 40%), AND DIFFUSE LARGE B-CELL LYMPHOMA (OVERALL RESPONSE RATE 31%). FURTHER INVESTIGATION OF THE SAFETY AND EFFICACY OF ABEXINOSTAT IN FOLLICULAR LYMPHOMA, T-CELL LYMPHOMA, AND DIFFUSE LARGE B-CELL LYMPHOMA IMPLEMENTING A LESS DOSE-INTENSE WEEK-ON-WEEK-OFF SCHEDULE IS WARRANTED. (TRIAL REGISTERED AT: EUDRACT-2009-013691-47). 2017