1 4334 78 MICRORNAS: NOVEL DIAGNOSTIC AND THERAPEUTIC TOOLS FOR PANCREATIC DUCTAL ADENOCARCINOMA? PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS KNOWN FOR ITS VERY POOR OVERALL PROGNOSIS, MAKING TOOLS FOR EARLY DIAGNOSIS AND NEW THERAPEUTIC MODALITIES URGENTLY NEEDED. MICRORNAS (MIRNAS), ENDOGENOUS NONCODING RNA MOLECULES OF APPROXIMATELY 22 NT, HAVE GAINED ATTENTION AS AN EPIGENETIC COMPONENT INVOLVED IN THE DEVELOPMENT OF MANY CANCERS, INCLUDING PDAC. MIRNA EXPRESSION PROFILES OF VARYING PANCREATIC TISSUES HAVE IDENTIFIED A NUMBER OF DIFFERENTIALLY EXPRESSED MIRNAS AND SEEM TO BE ABLE TO DIFFERENTIATE BETWEEN THREE TISSUES OF CLINICAL IMPORTANCE: NORMAL PANCREAS, CHRONIC PANCREATITIS, AND PDAC. THIS ARTICLE GATHERS OUR CURRENT KNOWLEDGE OF DIFFERENTIALLY EXPRESSED MIRNAS IN PANCREATIC TISSUES WITH RELEVANCE TO PDAC AND PRESENTS POTENTIAL DIAGNOSTIC AND THERAPEUTIC OPPORTUNITIES. 2009 2 6132 23 THE EPIGENETIC REGULATORS BMI1 AND RING1B ARE DIFFERENTIALLY REGULATED IN PANCREATITIS AND PANCREATIC DUCTAL ADENOCARCINOMA. CHRONIC PANCREATITIS AND PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) ARE ASSOCIATED WITH MAJOR CHANGES IN CELL DIFFERENTIATION. THESE CHANGES MAY BE AT THE BASIS OF THE INCREASED RISK FOR PDAC AMONG PATIENTS WITH CHRONIC PANCREATITIS. POLYCOMB PROTEINS ARE EPIGENETIC SILENCERS EXPRESSED IN ADULT STEM CELLS; UP-REGULATION OF POLYCOMB PROTEINS HAS BEEN REPORTED TO OCCUR IN A VARIETY OF SOLID TUMOURS SUCH AS COLON AND BREAST CANCER. WE HYPOTHESIZED THAT POLYCOMB MIGHT PLAY A ROLE IN PRENEOPLASTIC STATES IN THE PANCREAS AND IN TUMOUR DEVELOPMENT/PROGRESSION. TO TEST THESE IDEAS, WE DETERMINED THE EXPRESSION OF PRC1 COMPLEX PROTEINS (BMI1 AND RING1B) DURING PANCREATIC DEVELOPMENT AND IN PANCREATIC TISSUE FROM MOUSE MODELS OF DISEASE: ACUTE AND CHRONIC PANCREATIC INJURY, DUCT LIGATION, AND IN K-RAS(G12V) CONDITIONAL KNOCK-IN AND CAERULEIN-TREATED K-RAS(G12V) MICE. THE STUDY WAS EXTENDED TO HUMAN PANCREATIC TISSUE SAMPLES. TO OBTAIN MECHANISTIC INSIGHTS, BMI1 EXPRESSION IN CELLS UNDERGOING IN VITRO EXOCRINE CELL METAPLASIA AND THE EFFECTS OF BMI1 DEPLETION IN AN ACINAR CANCER CELL LINE WERE STUDIED. WE FOUND THAT BMI1 AND RING1B ARE EXPRESSED IN PANCREATIC EXOCRINE PRECURSOR CELLS DURING EARLY DEVELOPMENT AND IN DUCTAL AND ISLET CELLS-BUT NOT ACINAR CELLS-IN THE ADULT PANCREAS. BMI1 EXPRESSION WAS INDUCED IN ACINAR CELLS DURING ACUTE INJURY, IN ACINAR-DUCTAL METAPLASTIC LESIONS, AS WELL AS IN PANCREATIC INTRAEPITHELIAL NEOPLASIA (PANIN) AND PDAC. IN CONTRAST, RING1B EXPRESSION WAS ONLY SIGNIFICANTLY AND PERSISTENTLY UP-REGULATED IN HIGH-GRADE PANINS AND IN PDAC. BMI1 KNOCKDOWN IN CULTURED ACINAR TUMOUR CELLS LED TO CHANGES IN THE EXPRESSION OF VARIOUS DIGESTIVE ENZYMES. OUR RESULTS SUGGEST THAT BMI1 AND RING1B ARE MODULATED IN PANCREATIC DISEASES AND COULD CONTRIBUTE DIFFERENTLY TO TUMOUR DEVELOPMENT. 2009 3 3859 20 ISLET STRUCTURE AND FUNCTION IN THE GK RAT. TYPE 2 DIABETES MELLITUS (T2D) ARISES WHEN THE ENDOCRINE PANCREAS FAILS TO SECRETE SUFFICIENT INSULIN TO COPE WITH THE METABOLIC DEMAND BECAUSE OF BETA-CELL SECRETORY DYSFUNCTION AND/OR DECREASED BETA-CELL MASS. DEFINING THE NATURE OF THE PANCREATIC ISLET DEFECTS PRESENT IN T2D HAS BEEN DIFFICULT, IN PART BECAUSE HUMAN ISLETS ARE INACCESSIBLE FOR DIRECT STUDY. THIS REVIEW IS AIMED TO ILLUSTRATE TO WHAT EXTENT THE GOTO-KAKIZAKI RAT, ONE OF THE BEST CHARACTERIZED ANIMAL MODELS OF SPONTANEOUS T2D, HAS PROVED TO BE A VALUABLE TOOL OFFERING SUFFICIENT COMMONALITIES TO STUDY THIS ASPECT. A COMPREHENSIVE COMPENDIUM OF THE MULTIPLE FUNCTIONAL GK ISLET ABNORMALITIES SO FAR IDENTIFIED IS PROPOSED IN THIS PERSPECTIVE. THE PATHOGENESIS OF DEFECTIVE BETA-CELL NUMBER AND FUNCTION IN THE GK MODEL IS ALSO DISCUSSED. IT IS PROPOSED THAT THE DEVELOPMENT OF T2D IN THE GK MODEL RESULTS FROM THE COMPLEX INTERACTION OF MULTIPLE EVENTS: (I) SEVERAL SUSCEPTIBILITY LOCI CONTAINING GENES RESPONSIBLE FOR SOME DIABETIC TRAITS (DISTINCT LOCI ENCODING IMPAIRMENT OF BETA-CELL METABOLISM AND INSULIN EXOCYTOSIS, BUT NO QUANTITATIVE TRAIT LOCUS FOR DECREASED BETA-CELL MASS); (II) GESTATIONAL METABOLIC IMPAIRMENT INDUCING AN EPIGENETIC PROGRAMMING OF THE OFFSPRING PANCREAS (DECREASED BETA-CELL NEOGENESIS AND PROLIFERATION) TRANSMITTED OVER GENERATIONS; AND (III) LOSS OF BETA-CELL DIFFERENTIATION RELATED TO CHRONIC EXPOSURE TO HYPERGLYCAEMIA/HYPERLIPIDAEMIA, ISLET INFLAMMATION, ISLET OXIDATIVE STRESS, ISLET FIBROSIS AND PERTURBED ISLET VASCULATURE. 2010 4 6093 17 THE EFFECTS OF HIGH GLUCOSE EXPOSURE ON GLOBAL GENE EXPRESSION AND DNA METHYLATION IN HUMAN PANCREATIC ISLETS. BACKGROUND: TYPE 2 DIABETES (T2D) IS A COMPLEX DISEASE CHARACTERISED BY CHRONIC HYPERGLYCAEMIA. THE EFFECTS OF ELEVATED GLUCOSE ON GLOBAL GENE EXPRESSION IN COMBINATION WITH DNA METHYLATION PATTERNS HAVE NOT YET BEEN STUDIED IN HUMAN PANCREATIC ISLETS. OUR AIM WAS TO STUDY THE IMPACT OF 48 H EXPOSURE TO HIGH (19 MM) VERSUS CONTROL (5.6 MM) GLUCOSE LEVELS ON GLUCOSE-STIMULATED INSULIN SECRETION, GENE EXPRESSION AND DNA METHYLATION IN HUMAN PANCREATIC ISLETS. RESULTS: WHILE ISLETS KEPT AT 5.6 MM GLUCOSE SECRETED SIGNIFICANTLY MORE INSULIN IN RESPONSE TO SHORT TERM GLUCOSE-STIMULATION (P = 0.0067), ISLETS EXPOSED TO HIGH GLUCOSE FOR 48 H WERE DESENSITISED AND UNRESPONSIVE TO SHORT TERM GLUCOSE-STIMULATION WITH RESPECT TO INSULIN SECRETION (P = 0.32). MOREOVER, THE EXPOSURE OF HUMAN ISLETS TO 19 MM GLUCOSE RESULTED IN SIGNIFICANTLY ALTERED EXPRESSION OF EIGHT GENES (FDR<5%), WITH FIVE OF THESE (GLRA1, RASD1, VAC14, SLCO5A1, CHRNA5) ALSO EXHIBITING CHANGES IN DNA METHYLATION (P < 0.05). A GENE SET ENRICHMENT ANALYSIS OF THE EXPRESSION DATA SHOWED SIGNIFICANT ENRICHMENT OF E.G. TGF-BETA SIGNALLING PATHWAY, NOTCH SIGNALLING PATHWAY AND SNARE INTERACTIONS IN VESICULAR TRANSPORT; THESE PATHWAYS ARE OF RELEVANCE FOR ISLET FUNCTION AND POSSIBLY ALSO DIABETES. WE ALSO FOUND INCREASED DNA METHYLATION OF CPG SITES ANNOTATED TO PDX1 IN HUMAN ISLETS EXPOSED TO 19 MM GLUCOSE FOR 48 H. FINALLY, WE COULD FUNCTIONALLY VALIDATE A ROLE FOR GLRA1 IN INSULIN SECRETION. CONCLUSION: OUR DATA DEMONSTRATE THAT HIGH GLUCOSE LEVELS AFFECT HUMAN PANCREATIC ISLET GENE EXPRESSION AND SEVERAL OF THESE GENES ALSO EXHIBIT EPIGENETIC CHANGES. THIS MIGHT CONTRIBUTE TO THE IMPAIRED INSULIN SECRETION SEEN IN T2D. 2018 5 6539 27 TRANSCRIPTIONAL VARIATIONS IN THE WIDER PERITUMORAL TISSUE ENVIRONMENT OF PANCREATIC CANCER. TRANSCRIPTIONAL PROFILING WAS PERFORMED ON 452 RNA PREPARATIONS ISOLATED FROM VARIOUS TYPES OF PANCREATIC TISSUE FROM TUMOUR PATIENTS AND HEALTHY DONORS, WITH A PARTICULAR FOCUS ON PERITUMORAL SAMPLES. PANCREATIC DUCTAL ADENOCARCINOMAS (PDAC) AND CYSTIC TUMOURS WERE MOST DIFFERENT IN THESE NON-TUMOROUS TISSUES SURROUNDING THEM, WHEREAS THE ACTUAL TUMOURS EXHIBITED RATHER SIMILAR TRANSCRIPT PATTERNS. THE ENVIRONMENT OF CYSTIC TUMOURS WAS TRANSCRIPTIONALLY NEARLY IDENTICAL TO NORMAL PANCREAS TISSUE. IN CONTRAST, THE TISSUE AROUND PDAC BEHAVED A LOT LIKE THE TUMOUR, INDICATING SOME KIND OF FIELD DEFECT, WHILE SHOWING FAR LESS MOLECULAR RESEMBLANCE TO BOTH CHRONIC PANCREATITIS AND HEALTHY TISSUE. THIS SUGGESTS THAT THE MAJOR PATHOGENIC DIFFERENCE BETWEEN CYSTIC AND DUCTAL TUMOURS MAY BE DUE TO THEIR CELLULAR ENVIRONMENT RATHER THAN THE FEW VARIATIONS BETWEEN THE TUMOURS. LACK OF CORRELATION BETWEEN DNA METHYLATION AND TRANSCRIPT LEVELS MAKES IT UNLIKELY THAT THE OBSERVED FIELD DEFECT IN THE PERITUMORAL TISSUE OF PDAC IS CONTROLLED TO A LARGE EXTENT BY SUCH EPIGENETIC REGULATION. FUNCTIONALLY, A STRIKINGLY LARGE NUMBER OF AUTOPHAGY-RELATED TRANSCRIPTS WAS CHANGED IN BOTH PDAC AND ITS PERITUMORAL TISSUE, BUT NOT IN OTHER PANCREATIC TUMOURS. A TRANSCRIPTION SIGNATURE OF 15 AUTOPHAGY-RELATED GENES WAS ESTABLISHED THAT PERMITS A PROGNOSIS OF SURVIVAL WITH HIGH ACCURACY AND INDICATES THE ROLE OF AUTOPHAGY IN TUMOUR BIOLOGY. 2018 6 6163 16 THE GK RAT BETA-CELL: A PROTOTYPE FOR THE DISEASED HUMAN BETA-CELL IN TYPE 2 DIABETES? INCREASING EVIDENCE INDICATES THAT DECREASED FUNCTIONAL BETA-CELL MASS IS THE HALLMARK OF TYPE 2 DIABETES (T2D) MELLITUS. NOWADAYS, THE DEBATE FOCUSES ON THE POSSIBLE MECHANISMS RESPONSIBLE FOR ABNORMAL ISLET MICROENVIRONMENT, DECREASED BETA-CELL NUMBER, IMPAIRED BETA-CELL FUNCTION, AND THEIR MULTIFACTORIAL AETIOLOGIES. THIS REVIEW IS AIMED TO ILLUSTRATE TO WHAT EXTEND THE GOTO-KAKIZAKI RAT, ONE OF THE BEST CHARACTERIZED ANIMAL MODELS OF SPONTANEOUS T2D, HAS PROVED BE A VALUABLE TOOL OFFERING SUFFICIENT COMMONALITIES TO STUDY THESE ASPECTS. WE PROPOSE THAT THE DEFECTIVE BETA-CELL MASS AND FUNCTION IN THE GK MODEL REFLECT THE COMPLEX INTERACTIONS OF MULTIPLE PATHOGENIC PLAYERS: (I) SEVERAL INDEPENDENT LOCI CONTAINING GENES RESPONSIBLE FOR SOME DIABETIC TRAITS (BUT NOT DECREASED BETA-CELL MASS); (II) GESTATIONAL METABOLIC IMPAIRMENT INDUCING AN EPIGENETIC PROGRAMMING OF THE PANCREAS (DECREASED BETA-CELL NEOGENESIS AND/OR PROLIFERATION) WHICH IS TRANSMITTED TO THE NEXT GENERATION; AND (III) LOSS OF BETA-CELL DIFFERENTIATION DUE TO CHRONIC EXPOSURE TO HYPERGLYCEMIA/HYPERLIPIDEMIA, INFLAMMATORY MEDIATORS, OXIDATIVE STRESS AND TO PERTURBED ISLET MICROARCHITECTURE. 2009 7 1302 15 DEFECTIVE FUNCTIONAL BETA-CELL MASS AND TYPE 2 DIABETES IN THE GOTO-KAKIZAKI RAT MODEL. INCREASING EVIDENCE INDICATES THAT DECREASED FUNCTIONAL BETA-CELL MASS IS THE HALLMARK OF TYPE 2 DIABETES MELLITUS. THEREFORE, THE DEBATE FOCUSES ON THE POSSIBLE MECHANISMS RESPONSIBLE FOR ABNORMAL ISLET MICROENVIRONMENT, DECREASED BETA-CELL NUMBER, IMPAIRED BETA-CELL FUNCTION AND THEIR MULTIFACTORIAL ETIOLOGIES. THE INFORMATION AVAILABLE ON THE GOTO-KAKIZAKI/PAR RAT LINE, ONE OF THE BEST CHARACTERIZED ANIMAL MODELS OF SPONTANEOUS TYPE 2 DIABETES MELLITUS, ARE REVIEWED IN SUCH A PERSPECTIVE. WE PROPOSE THAT THE DEFECTIVE BETA-CELL MASS AND FUNCTION IN THE GOTO-KAKIZAKI/PAR MODEL REFLECT THE COMPLEX INTERACTIONS OF MULTIPLE PATHOGENIC PLAYERS, INCLUDING SEVERAL INDEPENDENT LOCI CONTAINING GENES RESPONSIBLE FOR SOME DIABETIC TRAITS (BUT NOT DECREASED BETA-CELL MASS), GESTATIONAL METABOLIC IMPAIRMENT INDUCING AN EPIGENETIC PROGRAMMING OF THE PANCREAS (DECREASED BETA-CELL NEOGENESIS), WHICH IS TRANSMITTED TO THE NEXT GENERATION, AND LOSS OF BETA-CELL DIFFERENTIATION DUE TO CHRONIC EXPOSURE TO HYPERGLYCEMIA, INFLAMMATORY MEDIATORS, OXIDATIVE STRESS AND PERTURBED ISLET MICROARCHITECTURE. 2007 8 1837 19 EFFECTS OF PALMITATE ON GENOME-WIDE MRNA EXPRESSION AND DNA METHYLATION PATTERNS IN HUMAN PANCREATIC ISLETS. BACKGROUND: CIRCULATING FREE FATTY ACIDS ARE OFTEN ELEVATED IN PATIENTS WITH TYPE 2 DIABETES (T2D) AND OBESE INDIVIDUALS. CHRONIC EXPOSURE TO HIGH LEVELS OF SATURATED FATTY ACIDS HAS DETRIMENTAL EFFECTS ON ISLET FUNCTION AND INSULIN SECRETION. ALTERED GENE EXPRESSION AND EPIGENETICS MAY CONTRIBUTE TO T2D AND OBESITY. HOWEVER, THERE IS LIMITED INFORMATION ON WHETHER FATTY ACIDS ALTER THE GENOME-WIDE TRANSCRIPTOME PROFILE IN CONJUNCTION WITH DNA METHYLATION PATTERNS IN HUMAN PANCREATIC ISLETS. TO DISSECT THE MOLECULAR MECHANISMS LINKING LIPOTOXICITY TO IMPAIRED INSULIN SECRETION, WE INVESTIGATED THE EFFECTS OF A 48 H PALMITATE TREATMENT IN VITRO ON GENOME-WIDE MRNA EXPRESSION AND DNA METHYLATION PATTERNS IN HUMAN PANCREATIC ISLETS. METHODS: GENOME-WIDE MRNA EXPRESSION WAS ANALYZED USING AFFYMETRIX GENECHIP((R)) HUMAN GENE 1.0 ST WHOLE TRANSCRIPT-BASED ARRAY (N = 13) AND GENOME-WIDE DNA METHYLATION WAS ANALYZED USING INFINIUM HUMANMETHYLATION450K BEADCHIP (N = 13) IN HUMAN PANCREATIC ISLETS EXPOSED TO PALMITATE OR CONTROL MEDIA FOR 48 H. A NON-PARAMETRIC PAIRED WILCOXON STATISTICAL TEST WAS USED TO ANALYZE MRNA EXPRESSION. APOPTOSIS WAS MEASURED USING APO-ONE((R)) HOMOGENEOUS CASPASE-3/7 ASSAY (N = 4). RESULTS: WHILE GLUCOSE-STIMULATED INSULIN SECRETION WAS DECREASED, THERE WAS NO SIGNIFICANT EFFECT ON APOPTOSIS IN HUMAN ISLETS EXPOSED TO PALMITATE. WE IDENTIFIED 1,860 DIFFERENTIALLY EXPRESSED GENES IN PALMITATE-TREATED HUMAN ISLETS. THESE INCLUDE CANDIDATE GENES FOR T2D, SUCH AS TCF7L2, GLIS3, HNF1B AND SLC30A8. ADDITIONALLY, GENES IN GLYCOLYSIS/GLUCONEOGENESIS, PYRUVATE METABOLISM, FATTY ACID METABOLISM, GLUTATHIONE METABOLISM AND ONE CARBON POOL BY FOLATE WERE DIFFERENTIALLY EXPRESSED IN PALMITATE-TREATED HUMAN ISLETS. PALMITATE TREATMENT ALTERED THE GLOBAL DNA METHYLATION LEVEL AND DNA METHYLATION LEVELS OF CPG ISLAND SHELVES AND SHORES, 5'UTR, 3'UTR AND GENE BODY REGIONS IN HUMAN ISLETS. MOREOVER, 290 GENES WITH DIFFERENTIAL EXPRESSION HAD A CORRESPONDING CHANGE IN DNA METHYLATION, FOR EXAMPLE, TCF7L2 AND GLIS3. IMPORTANTLY, OUT OF THE GENES DIFFERENTIALLY EXPRESSED DUE TO PALMITATE TREATMENT IN HUMAN ISLETS, 67 WERE ALSO ASSOCIATED WITH BMI AND 37 WERE DIFFERENTIALLY EXPRESSED IN ISLETS FROM T2D PATIENTS. CONCLUSION: OUR STUDY DEMONSTRATES THAT PALMITATE TREATMENT OF HUMAN PANCREATIC ISLETS GIVES RISE TO EPIGENETIC MODIFICATIONS THAT TOGETHER WITH ALTERED GENE EXPRESSION MAY CONTRIBUTE TO IMPAIRED INSULIN SECRETION AND T2D. 2014 9 6164 21 THE GK RAT: A PROTOTYPE FOR THE STUDY OF NON-OVERWEIGHT TYPE 2 DIABETES. TYPE 2 DIABETES MELLITUS (T2D) ARISES WHEN THE ENDOCRINE PANCREAS FAILS TO SECRETE SUFFICIENT INSULIN TO COPE WITH THE METABOLIC DEMAND BECAUSE OF BETA-CELL SECRETORY DYSFUNCTION AND/OR DECREASED BETA-CELL MASS. DEFINING THE NATURE OF THE PANCREATIC ISLET DEFECTS PRESENT IN T2D HAS BEEN DIFFICULT, IN PART BECAUSE HUMAN ISLETS ARE INACCESSIBLE FOR DIRECT STUDY. THIS REVIEW IS AIMED TO ILLUSTRATE TO WHAT EXTENT THE GOTO KAKIZAKI RAT, ONE OF THE BEST CHARACTERIZED ANIMAL MODELS OF SPONTANEOUS T2D, HAS PROVED TO BE A VALUABLE TOOL OFFERING SUFFICIENT COMMONALITIES TO STUDY THIS ASPECT. A COMPREHENSIVE COMPENDIUM OF THE MULTIPLE FUNCTIONAL GK ABNORMALITIES SO FAR IDENTIFIED IS PROPOSED IN THIS PERSPECTIVE, TOGETHER WITH THEIR TIME-COURSE AND INTERACTIONS. A SPECIAL FOCUS IS GIVEN TOWARD THE PATHOGENESIS OF DEFECTIVE BETA-CELL NUMBER AND FUNCTION IN THE GK MODEL. IT IS PROPOSED THAT THE DEVELOPMENT OF T2D IN THE GK MODEL RESULTS FROM THE COMPLEX INTERACTION OF MULTIPLE EVENTS: (1) SEVERAL SUSCEPTIBILITY LOCI CONTAINING GENES RESPONSIBLE FOR SOME DIABETIC TRAITS; (2) GESTATIONAL METABOLIC IMPAIRMENT INDUCING AN EPIGENETIC PROGRAMMING OF THE OFFSPRING PANCREAS AND THE MAJOR INSULIN TARGET TISSUES; AND (3) ENVIRONMENTALLY INDUCED LOSS OF BETA-CELL DIFFERENTIATION DUE TO CHRONIC EXPOSURE TO HYPERGLYCEMIA/HYPERLIPIDEMIA, INFLAMMATION, AND OXIDATIVE STRESS. 2012 10 599 22 BETA-CELL DIFFERENTIATION STATUS IN TYPE 2 DIABETES. TYPE 2 DIABETES (T2D) AFFECTS 415 MILLION PEOPLE WORLDWIDE AND IS CHARACTERIZED BY CHRONIC HYPERGLYCAEMIA AND INSULIN RESISTANCE, PROGRESSING TO INSUFFICIENT INSULIN PRODUCTION, AS A RESULT OF BETA-CELL FAILURE. OVER TIME, CHRONIC HYPERGLYCAEMIA CAN ULTIMATELY LEAD TO LOSS OF BETA-CELL FUNCTION, LEAVING PATIENTS INSULIN-DEPENDENT. UNTIL RECENTLY THE LOSS OF BETA-CELL MASS SEEN IN T2D WAS CONSIDERED TO BE THE RESULT OF INCREASED RATES OF APOPTOSIS; HOWEVER, IT HAS BEEN PROPOSED THAT APOPTOSIS ALONE CANNOT ACCOUNT FOR THE EXTENT OF BETA-CELL MASS LOSS SEEN IN THE DISEASE, AND THAT A LOSS OF FUNCTION MAY ALSO OCCUR AS A RESULT OF CHANGES IN BETA-CELL DIFFERENTIATION STATUS. IN THE PRESENT REVIEW, WE CONSIDER CURRENT KNOWLEDGE OF DETERMINANTS OF BETA-CELL FATE IN THE CONTEXT OF UNDERSTANDING ITS RELEVANCE TO DISEASE PROCESS IN T2D, AND ALSO THE IMPACT OF A DIABETOGENIC ENVIRONMENT (HYPERGLYCAEMIA, HYPOXIA, INFLAMMATION AND DYSLIPIDAEMIA) ON THE EXPRESSION OF GENES INVOLVED IN MAINTENANCE OF BETA-CELL IDENTITY. WE DESCRIBE CURRENT KNOWLEDGE OF THE IMPACT OF THE DIABETIC MICROENVIRONMENT ON GENE REGULATORY PROCESSES SUCH ALTERNATIVE SPLICING, THE EXPRESSION OF DISALLOWED GENES AND EPIGENETIC MODIFICATIONS. ELUCIDATING THE MOLECULAR MECHANISMS THAT UNDERPIN CHANGES TO BETA-CELL DIFFERENTIATION STATUS AND THE CONCOMITANT BETA-CELL FAILURE OFFERS POTENTIAL TREATMENT TARGETS FOR THE FUTURE MANAGEMENT OF PATIENTS WITH T2D. 2016 11 1435 31 DIFFERENTIAL METHYLATION LANDSCAPE OF PANCREATIC DUCTAL ADENOCARCINOMA AND ITS PRECANCEROUS LESIONS. BACKGROUND: PANCREATIC CANCER IS ONE OF THE MOST LETHAL DISEASES WITH AN INCIDENCE ALMOST EQUAL TO THE MORTALITY. IN ADDITION TO HAVING GENETIC CAUSES, CANCER CAN ALSO BE CONSIDERED AN EPIGENETIC DISEASE. DNA METHYLATION IS THE PREMIER EPIGENETIC MODIFICATION AND PATTERNS OF ABERRANT DNA METHYLATION ARE RECOGNIZED TO BE A COMMON HALLMARK OF HUMAN TUMOR. IN THE MULTISTAGE CARCINOGENESIS OF PANCREAS STARTING FROM PRECANCEROUS LESIONS TO PANCREATIC DUCTAL ADENOCARCINOMA (PDAC), THE EPIGENETIC CHANGES PLAY A SIGNIFICANT ROLE. DATA SOURCES: RELEVANT STUDIES FOR THIS REVIEW WERE DERIVED VIA AN EXTENSIVE LITERATURE SEARCH IN PUBMED VIA USING VARIOUS KEYWORDS SUCH AS PANCREATIC DUCTAL ADENOCARCINOMA, PRECANCEROUS LESIONS, METHYLATION PROFILE, EPIGENETIC BIOMARKERS THAT ARE RELEVANT DIRECTLY OR CLOSELY ASSOCIATED WITH THE CONCERNED AREA OF OUR INTEREST. THE LITERATURE SEARCH WAS INTENSIVELY DONE CONSIDERING A TIME FRAME OF 20 YEARS (1998-2018). RESULT: IN THIS REVIEW WE HAVE HIGHLIGHTED THE HYPERMETHYLATION AND HYPOMETHYLATION OF THE PRECANCEROUS PDAC LESIONS (PANCREATIC INTRA-EPITHELIAL NEOPLASIA, INTRADUCTAL PAPILLARY MUCINOUS NEOPLASM, MUCINOUS CYSTIC NEOPLASM AND CHRONIC PANCREATITIS) AND PDAC ALONG WITH THE POTENTIAL BIOMARKERS. WE HAVE ALSO ACHIEVED THE EARLY EPIGENETIC DRIVER THAT LEADS TO PROGRESSION FROM PRECANCEROUS LESIONS TO PDAC. A BUNCH OF EPIGENETIC DRIVER GENES LEADS TO PROGRESSION OF PRECANCEROUS LESIONS TO PDAC (PPENK, APC, P14/5/16/17, HMLH1 AND MGMT) ARE ALSO DOCUMENTED. WE SUMMARIZED THE IMPORTANCE OF THESE OBSERVATIONS IN THERAPEUTICS AND DIAGNOSIS OF PDAC HENCE IDENTIFYING THE POTENTIAL USE OF EPIGENETIC BIOMARKERS IN EPIGENETIC TARGETED THERAPY. EPIGENETIC INACTIVATION OCCURS BY HYPERMETHYLATION OF CPG ISLANDS IN THE PROMOTER REGIONS OF TUMOR SUPPRESSOR GENES. WE LISTED ALL HYPER- AND HYPOMETHYLATION OF CPG ISLANDS OF SEVERAL GENES IN PDAC INCLUDING ITS PRECANCEROUS LESIONS. CONCLUSIONS: THE CONCEPT OF THE REVIEW WOULD HELP TO UNDERSTAND THEIR BIOLOGICAL EFFECTS, AND TO DETERMINE WHETHER THEY MAY BE SUCCESSFULLY COMBINED WITH OTHER EPIGENETIC DRUGS. HOWEVER, WE NEED TO CONTINUE OUR RESEARCH TO DEVELOP MORE SPECIFIC DNA-DEMETHYLATING AGENTS, WHICH ARE THE TARGETS FOR HYPERMETHYLATED CPG METHYLATION SITES. 2020 12 507 32 ASSOCIATION OF INCREASED DNA METHYLTRANSFERASE EXPRESSION WITH CARCINOGENESIS AND POOR PROGNOSIS IN PANCREATIC DUCTAL ADENOCARCINOMA. INTRODUCTION: EPIGENETIC MODIFICATIONS PLAY AN IMPORTANT ROLE IN MULTISTAGE CARCINOGENESIS. THE ROLE OF THE THREE FUNCTIONAL DNA METHYLTRANSFERASES (DNMTS) IN PANCREATIC CARCINOGENESIS HAS NOT BEEN FULLY UNDERSTOOD. THE MAIN GOAL OF THIS STUDY WAS TO EXAMINE DNMT EXPRESSION IN DIFFERENT STAGES OF PANCREATIC DUCTAL ADENOCARCINOMA (PDAC), AND EVALUATE THEIR PROGNOSTIC SIGNIFICANCE IN PDAC. MATERIALS AND METHODS: A LARGE NUMBER OF PREMALIGNANT AND MALIGNANT PANCREATIC LESIONS WERE OBTAINED BY MANUAL MICRODISSECTION. QUANTITATIVE REAL-TIME RT-PCR WAS USED TO DETECT DNMTS MRNA EXPRESSION. NONPARAMETRIC TEST, LOGRANK TEST AND COX REGRESSION ANALYSIS WERE USED TO EVALUATE THE CLINICAL SIGNIFICANCE OF DNMT EXPRESSION. RESULTS: THE MRNA EXPRESSION OF THE THREE DNMTS INCREASED WITH THE DEVELOPMENT OF PANCREATIC CANCER FROM NORMAL DUCT TO PANCREATIC INTRADUCTAL NEOPLASIA AND FURTHER TO PDAC, AND WERE STATISTICALLY CORRELATED WITH EACH OTHER. EXPRESSION OF THE THREE DNMTS WAS STATISTICALLY CORRELATED WITH TNM STAGING AND HISTORY OF CHRONIC PANCREATITIS. DNMT3A AND DNMT3B, BUT NOT DNMT1 EXPRESSION, WAS STATISTICALLY CORRELATED WITH TUMOUR SIZE. PATIENTS WITH HIGHER LEVELS OF DNMT1, DNMT3A AND/OR DNMT3B EXPRESSION HAD AN OVERALL LOWER SURVIVAL THAN THOSE WITH LOWER LEVELS OF EXPRESSION. UNIVARIATE ANALYSIS SHOWED THAT HIGH EXPRESSION LEVELS OF DNMTS, ALCOHOL CONSUMPTION, TUMOUR DIFFERENTIATION AND TNM STAGING WERE STATISTICALLY SIGNIFICANT RISK FACTORS. MULTIVARIATE ANALYSIS SHOWED THAT HIGH LEVEL OF DNMT3B EXPRESSION AND TUMOUR DIFFERENTIATION WERE STATISTICALLY SIGNIFICANT INDEPENDENT POOR PROGNOSTIC FACTORS. CONCLUSIONS: THESE RESULTS SUGGESTED THAT PANCREATIC CARCINOGENESIS INVOLVES AN INCREASED MRNA EXPRESSION OF THREE DNMTS, AND THEY MAY BECOME VALUABLE DIAGNOSTIC AND PROGNOSTIC MARKERS AS WELL AS POTENTIAL THERAPEUTIC TARGETS FOR PANCREATIC CANCER. 2012 13 3673 24 INFLAMMATION AND DE-DIFFERENTIATION IN PANCREATIC CARCINOGENESIS. PANCREATIC CANCER IS A MALIGNANCY WITH AN EXTREMELY POOR PROGNOSIS. CHRONIC PANCREATITIS IS A WELL-KNOWN RISK FACTOR FOR PANCREATIC CANCER. INFLAMMATION IS THOUGHT TO INFLUENCE CARCINOGENESIS THROUGH DNA DAMAGE AND ACTIVATION OF INTRACELLULAR SIGNALING PATHWAYS. MANY TRANSCRIPTION FACTORS AND SIGNALING PATHWAYS CO-OPERATE TO DETERMINE AND MAINTAIN CELL IDENTITY AT EACH PHASE OF PANCREATIC ORGANOGENESIS AND CELL DIFFERENTIATION. RECENT STUDIES HAVE SHOWN THAT CARCINOGENESIS IS PROMOTED THROUGH THE SUPPRESSION OF TRANSCRIPTION FACTORS RELATED TO DIFFERENTIATION. PANCREATITIS ALSO DEMONSTRATES TRANSCRIPTIONAL CHANGES, SUGGESTING THAT MULTIFACTORIAL EPIGENETIC CHANGES LEAD TO IMPAIRED DIFFERENTIATION. TAKEN TOGETHER, THESE FACTORS MAY CONSTITUTE AN IMPORTANT FRAMEWORK FOR PANCREATIC CARCINOGENESIS. IN THIS REVIEW, WE DISCUSS THE ROLE OF INFLAMMATION AND DE-DIFFERENTIATION IN THE DEVELOPMENT OF PANCREATIC CANCER, AS WELL AS THE FUTURE OF NOVEL THERAPEUTIC APPLICATIONS. 2018 14 1280 30 DECIPHERING DNA METHYLATION SIGNATURES OF PANCREATIC CANCER AND PANCREATITIS. BACKGROUND: CHRONIC PANCREATITIS PRESENTS A HIGH RISK OF INFLAMMATION-RELATED PROGRESSION TO PANCREATIC CANCER. PANCREATIC CANCER IS THE FOURTH LEADING CAUSE OF CANCER-RELATED DEATH WORLDWIDE. THE HIGH MORTALITY RATE IS DIRECTLY RELATED TO THE DIFFICULTY IN PROMPTLY DIAGNOSING THE DISEASE, WHICH OFTEN PRESENTS AS OVERT AND ADVANCED. HENCE, EARLY DIAGNOSIS FOR PANCREATIC CANCER BECOMES CRUCIAL, PROPELLING RESEARCH INTO THE MOLECULAR AND EPIGENETIC LANDSCAPE OF THE DISEASE. MAIN BODY: RECENT STUDIES HAVE SHOWN THAT CELL-FREE DNA METHYLATION PROFILES FROM INFLAMMATORY DISEASES OR CANCER CAN VARY, THUS OPENING A NEW VENUE FOR THE DEVELOPMENT OF BIOMARKERS FOR EARLY DIAGNOSIS. IN PARTICULAR, CELL-FREE DNA METHYLATION COULD BE EMPLOYED IN THE IDENTIFICATION OF PRE-NEOPLASTIC SIGNATURES IN INDIVIDUALS WITH SUSPECTED PANCREATIC CONDITIONS, REPRESENTING A SPECIFIC AND NON-INVASIVE METHOD OF EARLY DIAGNOSIS OF PANCREATIC CANCER. IN THIS REVIEW, WE DESCRIBE THE MOLECULAR DETERMINANTS OF PANCREATIC CANCER AND HOW THESE ARE RELATED TO CHRONIC PANCREATITIS. WE WILL THEN PRESENT AN OVERVIEW OF DIFFERENTIAL METHYLATED GENES IN THE TWO CONDITIONS, HIGHLIGHTING THEIR DIAGNOSTIC OR PROGNOSTIC POTENTIAL. CONCLUSION: EXPLOITING THE RELATION BETWEEN ABNORMALLY METHYLATED CELL-FREE DNA AND PRE-NEOPLASTIC LESIONS OR CHRONIC PANCREATITIS MAY BECOME A GAME-CHANGING APPROACH FOR THE DEVELOPMENT OF TOOLS FOR THE EARLY DIAGNOSIS OF PANCREATIC CANCER. 2019 15 1741 29 EARLY EPIGENETIC DOWNREGULATION OF MICRORNA-192 EXPRESSION PROMOTES PANCREATIC CANCER PROGRESSION. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS CHARACTERIZED BY VERY EARLY METASTASIS, SUGGESTING THE HYPOTHESIS THAT METASTASIS-ASSOCIATED CHANGES MAY OCCUR PRIOR TO ACTUAL TUMOR FORMATION. IN THIS STUDY, WE IDENTIFIED MIR-192 AS AN EPIGENETICALLY REGULATED SUPPRESSOR GENE WITH PREDICTIVE VALUE IN THIS DISEASE. MIR-192 WAS DOWNREGULATED BY PROMOTER METHYLATION IN BOTH PDAC AND CHRONIC PANCREATITIS, THE LATTER OF WHICH IS A MAJOR RISK FACTOR FOR THE DEVELOPMENT OF PDAC. FUNCTIONAL STUDIES IN VITRO AND IN VIVO IN MOUSE MODELS OF PDAC SHOWED THAT OVEREXPRESSION OF MIR-192 WAS SUFFICIENT TO REDUCE CELL PROLIFERATION AND INVASION. MECHANISTIC ANALYSES CORRELATED CHANGES IN MIR-192 PROMOTER METHYLATION AND EXPRESSION WITH EPITHELIAL-MESENCHYMAL TRANSITION. CELL PROLIFERATION AND INVASION WERE LINKED TO ALTERED EXPRESSION OF THE MIR-192 TARGET GENE SERPINE1 THAT IS ENCODING THE PROTEIN PLASMINOGEN ACTIVATOR INHIBITOR-1 (PAI-1), AN ESTABLISHED REGULATOR OF THESE PROPERTIES IN PDAC CELLS. NOTABLY, OUR DATA SUGGESTED THAT INVASIVE CAPACITY WAS ALTERED EVEN BEFORE NEOPLASTIC TRANSFORMATION OCCURRED, AS TRIGGERED BY MIR-192 DOWNREGULATION. OVERALL, OUR RESULTS HIGHLIGHTED A ROLE FOR MIR-192 IN EXPLAINING THE EARLY METASTATIC BEHAVIOR OF PDAC AND SUGGESTED ITS RELEVANCE AS A TARGET TO DEVELOP FOR EARLY DIAGNOSTICS AND THERAPY. CANCER RES; 76(14); 4149-59. (C)2016 AACR. 2016 16 778 31 CELL-FREE DNA METHYLATION: THE NEW FRONTIERS OF PANCREATIC CANCER BIOMARKERS' DISCOVERY. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS AMONG THE MOST LETHAL CANCER TYPES WORLD-WIDE. ITS HIGH MORTALITY IS RELATED TO THE DIFFICULTY IN THE DIAGNOSIS, WHICH OFTEN OCCURS WHEN THE DISEASE IS ALREADY ADVANCED. AS OF TODAY, NO EARLY DIAGNOSTIC TESTS ARE AVAILABLE, WHILE ONLY A LIMITED NUMBER OF PROGNOSTIC TESTS HAVE REACHED CLINICAL PRACTICE. THE MAIN REASON IS THE LACK OF RELIABLE BIOMARKERS THAT ARE ABLE TO CAPTURE THE EARLY DEVELOPMENT OR THE PROGRESSION OF THE DISEASE. HENCE, THE DISCOVERY OF BIOMARKERS FOR EARLY DIAGNOSIS OR PROGNOSIS OF PDAC REMAINS, DE FACTO, AN UNMET NEED. AN INCREASING NUMBER OF STUDIES HAS SHOWN THAT CELL-FREE DNA (CFDNA) METHYLATION ANALYSIS REPRESENTS A PROMISING NON-INVASIVE APPROACH FOR THE DISCOVERY OF BIOMARKERS WITH DIAGNOSTIC OR PROGNOSTIC POTENTIAL. IN PARTICULAR, CFDNA METHYLATION COULD BE UTILIZED FOR THE IDENTIFICATION OF DISEASE-SPECIFIC SIGNATURES IN PRE-NEOPLASTIC LESIONS OR CHRONIC PANCREATITIS (CP), REPRESENTING A SENSITIVE AND NON-INVASIVE METHOD OF EARLY DIAGNOSIS OF PDAC. IN THIS REVIEW, WE WILL DISCUSS THE ADVANTAGES AND PITFALLS OF CFDNA METHYLATION STUDIES. FURTHER, WE WILL PRESENT THE CURRENT ADVANCES IN THE DISCOVERY OF PANCREATIC CANCER BIOMARKERS WITH EARLY DIAGNOSTIC OR PROGNOSTIC POTENTIAL, FOCUSING ON PANCREAS-SPECIFIC (E.G., CUX2 OR REG1A) OR ABNORMAL (E.G., ADAMTS1 OR BNC1) CFDNA METHYLATION SIGNATURES IN HIGH RISK PRE-NEOPLASTIC CONDITIONS AND PDAC. 2019 17 6596 27 TUMOR-SUPPRESSIVE MIR-192-5P HAS PROGNOSTIC VALUE IN PANCREATIC DUCTAL ADENOCARCINOMA. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS CHARACTERIZED BY FAST TUMOR PROGRESSION AND DIAGNOSIS AT ADVANCED, INOPERABLE STAGES. PREVIOUS STUDIES COULD DEMONSTRATE AN INVOLVEMENT OF MIR-192-5P IN EPIGENETIC REGULATION OF VISCERAL CARCINOMAS. DUE TO CONTRADICTORY RESULTS, HOWEVER, THE CLINICAL UTILITY OF MIR-192-5P IN PDAC HAS YET TO BE DETERMINED. MIR-192-5P EXPRESSION WAS ANALYZED BY RT-QRT-PCR IN HUMAN PDAC AND BENIGN TISSUE (N = 78), BLOOD SERUM (N = 81) AND SERUM EXOSOMES (N = 74), AS WELL AS IN PDAC CELL LINES (N = 5), CHEMORESISTANT CELL CLONES (N = 2), AND PANCREATIC DUCT CELL LINE H6C7. ANALYSIS OF EMT-ASSOCIATED (EPITHELIAL-TO-MESENCHYMAL TRANSITION) PROTEINS WAS PERFORMED BY IMMUNOHISTOCHEMISTRY AND WESTERN BLOT. MIR-192-5P WAS DEREGULATED IN PDAC AS COMPARED TO HEALTHY CONTROLS (HCS), WITH DOWNREGULATION IN MACRODISSECTED TISSUE (P < 0.001) AND UPREGULATION IN BLOOD SERUM OF PDAC UICC (UNION FOR INTERNATIONAL CANCER CONTROL) STAGE IV (P = 0.016) AND SERUM EXOSOMES OF PDAC UICC STAGES II TO IV (P < 0.001). MIR-192-5P EXPRESSION IN TUMOR TISSUE WAS SIGNIFICANTLY LOWER AS COMPARED TO CORRESPONDING PERITUMORAL TISSUE (PDAC UICC STAGE II: P < 0.001; PDAC UICC STAGE III: P = 0.024), WHILE EMT MARKERS ZEB1 AND ZEB2 WERE MORE FREQUENTLY EXPRESSED IN TUMOR TISSUE AS COMPARED TO PERITUMORAL TISSUE, HCS, AND CHRONIC PANCREATITIS. TISSUE-DERIVED (AUC OF 0.86; P < 0.0001) AND EXOSOMAL (AUC OF 0.83; P = 0.0004) MIR-192-5P COULD DIFFERENTIATE BETWEEN PDAC AND HCS WITH GOOD ACCURACY. FURTHERMORE, HIGH EXPRESSION OF MIR-192-5P IN PDAC TISSUE OF CURATIVELY RESECTED PDAC PATIENTS CORRELATED WITH PROLONGED OVERALL AND RECURRENCE-FREE SURVIVAL IN MULTIVARIATE ANALYSIS. IN VITRO, MIR-192-5P WAS DOWNREGULATED IN GEMCITABINE-RESISTANT CELL CLONES OF ASPC-1 (P = 0.029). TRANSIENT TRANSFECTION OF MIA PACA-2 CELLS WITH MIR-192-5P MIMIC RESULTED IN DOWNREGULATION OF ZEB2. MIR-192-5P SEEMS TO POSSESS A TUMOR-SUPPRESSIVE ROLE AND HIGH POTENTIAL AS A DIAGNOSTIC AND PROGNOSTIC MARKER IN PDAC. 2020 18 780 28 CELL-FREE DNA PROMOTER HYPERMETHYLATION IN PLASMA AS A DIAGNOSTIC MARKER FOR PANCREATIC ADENOCARCINOMA. BACKGROUND: PANCREATIC CANCER HAS A 5-YEAR SURVIVAL RATE OF ONLY 5-7%. DIFFICULTIES IN DETECTING PANCREATIC CANCER AT EARLY STAGES RESULTS IN THE HIGH MORTALITY AND SUBSTANTIATES THE NEED FOR ADDITIONAL DIAGNOSTIC TOOLS. SURGERY IS THE ONLY CURATIVE TREATMENT AND UNFORTUNATELY ONLY POSSIBLE IN LOCALIZED TUMOURS. A DIAGNOSTIC BIOMARKER FOR PANCREATIC CANCER WILL HAVE A MAJOR IMPACT ON PATIENT SURVIVAL BY FACILITATING EARLY DETECTION AND THE POSSIBILITY FOR CURATIVE TREATMENT. DNA PROMOTER HYPERMETHYLATION IS A MECHANISM OF EARLY CARCINOGENESIS, WHICH CAN CAUSE INACTIVATION OF TUMOUR SUPPRESSOR GENES. THE AIM OF THIS STUDY WAS TO EXAMINE PROMOTER HYPERMETHYLATION IN A PANEL OF SELECTED GENES FROM CELL-FREE DNA, AS A DIAGNOSTIC MARKER FOR PANCREATIC ADENOCARCINOMA. METHODS: PATIENTS WITH SUSPECTED OR BIOPSY-VERIFIED PANCREATIC CANCER WERE INCLUDED PROSPECTIVELY AND CONSECUTIVELY. PATIENTS WITH CHRONIC/ACUTE PANCREATITIS WERE INCLUDED AS ADDITIONAL BENIGN CONTROL GROUPS. BASED ON AN OPTIMIZED ACCELERATED BISULFITE TREATMENT PROTOCOL, METHYLATION-SPECIFIC PCR OF A 28 GENE PANEL WAS PERFORMED ON PLASMA SAMPLES. A DIAGNOSTIC PREDICTION MODEL WAS DEVELOPED BY MULTIVARIABLE LOGISTIC REGRESSION ANALYSIS USING BACKWARD STEPWISE ELIMINATION. RESULTS: PATIENTS WITH PANCREATIC ADENOCARCINOMA (N = 95), CHRONIC PANCREATITIS (N = 97) AND ACUTE PANCREATITIS (N = 59) AND PATIENTS SCREENED, BUT NEGATIVE FOR PANCREATIC ADENOCARCINOMA (N = 27), WERE INCLUDED. THE DIFFERENCE IN MEAN NUMBER OF METHYLATED GENES IN THE CANCER GROUP (8.41 (95% CI 7.62-9.20)) VS THE TOTAL CONTROL GROUP (4.74 (95% CI 4.40-5.08)) WAS HIGHLY SIGNIFICANT (P < 0.001). A DIAGNOSTIC PREDICTION MODEL (AGE >65, BMP3, RASSF1A, BNC1, MESTV2, TFPI2, APC, SFRP1 AND SFRP2) HAD AN AREA UNDER THE CURVE OF 0.86 (SENSITIVITY 76%, SPECIFICITY 83%). THE MODEL PERFORMANCE WAS INDEPENDENT OF CANCER STAGE. CONCLUSIONS: CELL-FREE DNA PROMOTER HYPERMETHYLATION HAS THE POTENTIAL TO BE A DIAGNOSTIC MARKER FOR PANCREATIC ADENOCARCINOMA AND DIFFERENTIATE BETWEEN MALIGNANT AND BENIGN PANCREATIC DISEASE. THIS STUDY BRINGS US CLOSER TO A CLINICAL USEFUL DIAGNOSTIC MARKER FOR PANCREATIC CANCER, WHICH IS URGENTLY NEEDED. EXTERNAL VALIDATION IS, HOWEVER, REQUIRED BEFORE THE TEST CAN BE APPLIED IN THE CLINIC. TRIAL REGISTRATION: CLINICALTRIALS.GOV, NCT02079363. 2016 19 1158 21 CONTEXT-DEPENDENT EPIGENETIC REGULATION OF NUCLEAR FACTOR OF ACTIVATED T CELLS 1 IN PANCREATIC PLASTICITY. BACKGROUND & AIMS: THE ABILITY OF EXOCRINE PANCREATIC CELLS TO CHANGE THE CELLULAR PHENOTYPE IS REQUIRED FOR TISSUE REGENERATION UPON INJURY, BUT ALSO CONTRIBUTES TO THEIR MALIGNANT TRANSFORMATION AND TUMOR PROGRESSION. WE INVESTIGATED CONTEXT-DEPENDENT SIGNALING AND TRANSCRIPTION MECHANISMS THAT DETERMINE PANCREATIC CELL FATE DECISIONS TOWARD REGENERATION AND MALIGNANCY. IN PARTICULAR, WE STUDIED THE FUNCTION AND REGULATION OF THE INFLAMMATORY TRANSCRIPTION FACTOR NUCLEAR FACTOR OF ACTIVATED T CELLS 1 (NFATC1) IN PANCREATIC CELL PLASTICITY AND TISSUE ADAPTATION. METHODS: WE ANALYZED CELL PLASTICITY DURING PANCREATIC REGENERATION AND TRANSFORMATION IN MICE WITH PANCREAS-SPECIFIC EXPRESSION OF A CONSTITUTIVELY ACTIVE FORM OF NFATC1, OR DEPLETION OF ENHANCER OF ZESTE 2 HOMOLOGUE 2 (EZH2), IN THE CONTEXT OF WILD-TYPE OR CONSTITUTIVELY ACTIVATE KRAS, RESPECTIVELY. ACUTE AND CHRONIC PANCREATITIS WERE INDUCED BY INTRAPERITONEAL INJECTION OF CAERULEIN. EZH2-DEPENDENT REGULATION OF NFATC1 EXPRESSION WAS STUDIED IN MOUSE IN HUMAN PANCREATIC TISSUE AND CELLS BY IMMUNOHISTOCHEMISTRY, IMMUNOBLOTTING, AND QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION. WE USED GENETIC AND PHARMACOLOGIC APPROACHES OF EZH2 AND NFATC1 INHIBITION TO STUDY THE CONSEQUENCES OF PATHWAY DISRUPTION ON PANCREATIC MORPHOLOGY AND FUNCTION. EPIGENETIC MODIFICATIONS ON THE NFATC1 GENE WERE INVESTIGATED BY CHROMATIN IMMUNOPRECIPITATION ASSAYS. RESULTS: NFATC1 WAS RAPIDLY AND TRANSIENTLY INDUCED IN EARLY ADAPTATION TO ACINAR CELL INJURY IN HUMAN SAMPLES AND IN MICE, WHERE IT PROMOTED ACINAR CELL TRANSDIFFERENTIATION AND BLOCKED PROLIFERATION OF METAPLASTIC PANCREATIC CELLS. HOWEVER, IN LATE STAGES OF REGENERATION, NFATC1 WAS EPIGENETICALLY SILENCED BY EZH2-DEPENDENT HISTONE METHYLATION, TO ENABLE ACINAR CELL REDIFFERENTIATION AND PREVENT ORGAN ATROPHY AND EXOCRINE INSUFFICIENCY. IN CONTRAST, ONCOGENIC ACTIVATION OF KRAS SIGNALING IN PANCREATIC DUCTAL ADENOCARCINOMA CELLS REVERSED THE EZH2-DEPENDENT EFFECTS ON THE NFATC1 GENE AND WAS REQUIRED FOR EZH2-MEDIATED TRANSCRIPTIONAL ACTIVATION OF NFATC1. CONCLUSIONS: IN STUDIES OF HUMAN AND MOUSE PANCREATIC CELLS AND TISSUE, WE IDENTIFIED CONTEXT-SPECIFIC EPIGENETIC REGULATION OF NFATC1 ACTIVITY AS AN IMPORTANT MECHANISM OF PANCREATIC CELL PLASTICITY. INHIBITORS OF EZH2 MIGHT THEREFORE INTERFERE WITH ONCOGENIC ACTIVITY OF NFATC1 AND BE USED IN TREATMENT OF PANCREATIC DUCTAL ADENOCARCINOMA. 2017 20 5250 21 PROGRAMMED DISORDERS OF BETA-CELL DEVELOPMENT AND FUNCTION AS ONE CAUSE FOR TYPE 2 DIABETES? THE GK RAT PARADIGM. NOW THAT THE REDUCTION IN BETA-MASS HAS BEEN CLEARLY ESTABLISHED IN HUMANS WITH TYPE 2 DIABETES MELLITUS (T2DM) 1-4, THE DEBATE FOCUSES ON THE POSSIBLE MECHANISMS RESPONSIBLE FOR DECREASED BETA-CELL NUMBER AND IMPAIRED BETA-CELL FUNCTION AND THEIR MULTIFACTORIAL ETIOLOGY. APPROPRIATE INBRED RODENT MODELS ARE ESSENTIAL TOOLS FOR IDENTIFICATION OF GENES AND ENVIRONMENTAL FACTORS THAT INCREASE THE RISK OF ABNORMAL BETA-CELL FUNCTION AND OF T2DM. THE INFORMATION AVAILABLE IN THE GOTO-KAKIZAKI (GK) RAT, ONE OF THE BEST CHARACTERIZED ANIMAL MODELS OF SPONTANEOUS T2DM, ARE REVIEWED IN SUCH A PERSPECTIVE. WE PROPOSE THAT THE DEFECTIVE BETA-CELL MASS AND FUNCTION IN THE GK MODEL REFLECT THE COMPLEX INTERACTIONS OF THREE PATHOGENIC PLAYERS: (1) SEVERAL INDEPENDENT LOCI CONTAINING GENES CAUSING IMPAIRED INSULIN SECRETION; (2) GESTATIONAL METABOLIC IMPAIRMENT INDUCING A PROGRAMMING OF ENDOCRINE PANCREAS (DECREASED BETA-CELL NEOGENESIS) WHICH IS TRANSMITTED TO THE NEXT GENERATION; AND (3) SECONDARY (ACQUIRED) LOSS OF BETA-CELL DIFFERENTIATION DUE TO CHRONIC EXPOSURE TO HYPERGLYCEMIA (GLUCOTOXICITY). AN IMPORTANT MESSAGE IS THAT THE 'HERITABLE' DETERMINANTS OF T2DM ARE NOT SIMPLY DEPENDANT ON GENETIC FACTORS, BUT PROBABLY INVOLVE TRANSGENERATIONAL EPIGENETIC RESPONSES. 2005