1 1131 123 COMPREHENSIVE CIRCULAR RNA EXPRESSION PROFILING WITH ASSOCIATED CERNA NETWORK REVEALS THEIR THERAPEUTIC POTENTIAL IN CHOLESTEATOMA. CHOLESTEATOMA IS A CHRONIC DISEASE THAT PATHOLOGICALLY DISPLAYS A BENIGN TUMOR WITH EXCESSIVE SQUAMOUS EPITHELIAL CELL PROLIFERATION IN THE MIDDLE EAR. CLINICALLY, HOWEVER, IT CAN MANIFEST MALIGNANT BEHAVIOR BY DESTROYING ADJACENT TISSUES AND ORGANS. ALTHOUGH PREVIOUS STUDIES HAVE DEMONSTRATED THAT THE PATHOGENESIS OF CHOLESTEATOMA IS CORRELATED WITH EPIGENETIC DYSREGULATION, THE EXACT MECHANISM REMAINS UNCLEAR. CIRCULAR RNAS (CIRCRNAS) HAVE BEEN REVEALED AS BEING ABUNDANTLY EXPRESSED IN VARIOUS ORGANISMS AND HAVE BEEN FOUND TO CONTRIBUTE TO THE REGULATION OF MANY DISEASES. TO DATE, NO REPORTS HAVE ELUCIDATED THEIR EXPRESSION PROFILES AND FUNCTIONS IN CHOLESTEATOMA. IN THE PRESENT STUDY, THE CIRCRNA EXPRESSION PROFILE IN CHOLESTEATOMA WAS EXPLORED FOR THE FIRST TIME BY USING MICROARRAY ANALYSIS. WE OBTAINED A TOTAL OF 355 SIGNIFICANTLY DIFFERENTIALLY EXPRESSED CIRCRNAS IN CHOLESTEATOMA, AMONG WHICH 101 WERE IDENTIFIED TO BE UPREGULATED AND 254 DOWNREGULATED. BY CONSTRUCTING CIRCRNA?LNCRNA?MIRNA?MRNA COMPETING ENDOGENOUS RNA (CERNA) NETWORK, IT WAS DISCOVERED THAT CIRCRNAS MAY FUNCTION AS CERNAS AND CONTRIBUTE TO THE FORMATION OF CHOLESTEATOMA. THESE RESULTS PROVIDE NOVEL INSIGHT INTO THE PATHOGENESIS OF CHOLESTEATOMA AND SUGGEST CIRCRNAS AS POTENTIAL PROMISING THERAPEUTIC TARGETS FOR CHOLESTEATOMA. 2020 2 2909 35 GENE EXPRESSION PROFILING IN FIBROMYALGIA INDICATES AN AUTOIMMUNE ORIGIN OF THE DISEASE AND OPENS NEW AVENUES FOR TARGETED THERAPY. FIBROMYALGIA IS A CHRONIC DISORDER CHARACTERIZED BY WIDESPREAD PAIN AND BY SEVERAL NON-PAIN SYMPTOMS. AUTOIMMUNITY, SMALL FIBER NEUROPATHY AND NEUROINFLAMMATION HAVE BEEN SUGGESTED TO BE INVOLVED IN THE PATHOGENESIS OF THE DISEASE. WE HAVE INVESTIGATED THE GENE EXPRESSION PROFILE IN PERIPHERAL BLOOD MONONUCLEAR CELLS OBTAINED FROM TEN PATIENTS AND TEN HEALTHY SUBJECTS. OF THE 545,500 TRANSCRIPTS ANALYZED, 1673 RESULTED MODULATED IN FIBROMYALGIC PATIENTS. THE MAJORITY OF THESE GENES ARE INVOLVED IN BIOLOGICAL PROCESSES AND PATHWAYS LINKED TO THE CLINICAL MANIFESTATIONS OF THE DISEASE. MOREOVER, GENES INVOLVED IN IMMUNOLOGICAL PATHWAYS CONNECTED TO INTERLEUKIN-17 AND TO TYPE I INTERFERON SIGNATURES WERE ALSO MODULATED, SUGGESTING THAT AUTOIMMUNITY PLAYS A ROLE IN THE DISEASE. WE THEN AIMED AT IDENTIFYING DIFFERENTIALLY EXPRESSED LONG NON-CODING RNAS (LNCRNAS) FUNCTIONALLY CONNECTED TO MODULATED GENES BOTH DIRECTLY AND VIA MICRORNA TARGETING. ONLY TWO LNCRNAS OF THE 298 FOUND MODULATED IN PATIENTS, WERE ABLE TO TARGET THE MOST HIGHLY CONNECTED GENES IN THE FIBROMYALGIA INTERACTOME, SUGGESTING THEIR INVOLVEMENT IN CRUCIAL GENE REGULATION. OUR GENE EXPRESSION DATA WERE CONFIRMED BY REAL TIME PCR, BY AUTOANTIBODY TESTING, DETECTION OF SOLUBLE MEDIATORS AND TH-17 POLARIZATION IN A VALIDATION COHORT OF 50 PATIENTS. OUR RESULTS INDICATE THAT GENETIC AND EPIGENETIC MECHANISMS AS WELL AS AUTOIMMUNITY PLAY A PIVOTAL ROLE IN THE PATHOGENESIS OF FIBROMYALGIA. 2020 3 1508 38 DNA METHYLATION AND MRNA AND MICRORNA EXPRESSION OF SLE CD4+ T CELLS CORRELATE WITH DISEASE PHENOTYPE. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS AN AUTOIMMUNE DISEASE WELL KNOWN FOR ITS CLINICAL HETEROGENEITY, AND ITS ETIOLOGY SECONDARY TO A CROSS-TALK INVOLVING GENETIC PREDISPOSITION AND ENVIRONMENTAL STIMULI. ALTHOUGH GENOME-WIDE ANALYSIS HAS CONTRIBUTED GREATLY TO OUR UNDERSTANDING OF THE GENETIC BASIS OF SLE, THERE IS INCREASING EVIDENCE FOR A ROLE OF EPIGENETICS. INDEED, RECENT DATA HAVE DEMONSTRATED THAT IN PATIENTS WITH SLE, THERE ARE STRIKING ALTERATIONS OF DNA METHYLATION, HISTONE MODIFICATIONS, AND DEREGULATED MICRORNA EXPRESSION, THE SUM OF WHICH CONTRIBUTE TO OVER-EXPRESSION OF SELECT AUTOIMMUNE-RELATED GENES AND LOSS OF TOLERANCE. TO ADDRESS THIS ISSUE AT THE LEVEL OF CLINICAL PHENOTYPE, WE PERFORMED DNA METHYLATION, MRNA AND MICRORNA EXPRESSION SCREENING USING HIGH-THROUGHPUT SEQUENCING OF PURIFIED CD4+ T CELLS FROM PATIENTS WITH SLE, COMPARED TO AGE AND SEX MATCHED CONTROLS. IN PARTICULAR, WE STUDIED 42 PATIENTS WITH SLE AND DIVIDED THIS GROUP INTO THREE CLINICAL PHENOTYPES: A) THE PRESENCE OF SKIN LESIONS WITHOUT SIGNS OF SYSTEMIC PATHOLOGY; B) SKIN LESIONS BUT ALSO CHRONIC RENAL PATHOLOGY; AND C) SKIN LESIONS, CHRONIC RENAL PATHOLOGY AND POLYARTICULAR DISEASE. INTERESTINGLY, AND AS EXPECTED, SEQUENCING DATA REVEALED CHANGES IN DNA METHYLATION IN SLE COMPARED TO CONTROLS. HOWEVER, AND MORE IMPORTANTLY, ALTHOUGH THERE WERE COMMON METHYLATION CHANGES FOUND IN ALL GROUPS OF SLE COMPARED TO CONTROLS, THERE WAS SPECIFIC DNA METHYLATION CHANGES THAT CORRELATED WITH CLINICAL PHENOTYPE. THESE INCLUDED CHANGES IN THE NOVEL KEY TARGET GENES NLRP2, CD300LB AND S1PR3, AS WELL AS CHANGES IN THE CRITICAL PATHWAYS, INCLUDING THE ADHERENS JUNCTION AND LEUKOCYTE TRANSENDOTHELIAL MIGRATION. WE ALSO NOTED THAT A SIGNIFICANT PROPORTION OF GENES UNDERGOING DNA METHYLATION CHANGES WERE INVERSELY CORRELATED WITH GENE EXPRESSION AND THAT MIRNA SCREENING REVEALED THE EXISTENCE OF SUBSETS WITH CHANGES IN EXPRESSION. INTEGRATED ANALYSIS OF THIS DATA HIGHLIGHTS SPECIFIC SETS OF MIRNAS CONTROLLED BY DNA METHYLATION, AND GENES THAT ARE ALTERED BY METHYLATION AND TARGETED BY MIRNAS. IN CONCLUSION, OUR FINDINGS SUGGEST SELECT EPIGENETIC MECHANISMS THAT CONTRIBUTE TO CLINICAL PHENOTYPES AND FURTHER SHED LIGHT ON A NEW VENUE FOR BASIC SLE RESEARCH. 2014 4 1020 26 CIRCRNAS IN ATHEROSCLEROSIS, WITH SPECIAL EMPHASIS ON THE SPONGY EFFECT OF CIRCRNAS ON MIRNAS. ATHEROSCLEROSIS (AS) IS A CHRONIC INFLAMMATORY DISEASE, WHICH LEADS TO ATHEROSCLEROTIC RUPTURE, LUMEN STENOSIS AND THROMBOSIS, AND OFTEN ENDANGERS LIFE. CIRCULAR RNAS (CIRCRNAS) ARE A SPECIAL CLASS OF NON-CODING RNA MOLECULES, WHOSE ABNORMAL EXPRESSION HAS BEEN PROVED TO BE CLOSELY RELATED TO HUMAN DISEASES, INCLUDING AS. BOTH THE ABNORMAL REGULATION OF CIRCRNAS AND THE SPONGING EFFECT ON MIRNAS WOULD LEAD TO CHANGES IN GENE EXPRESSION IN THE FORM OF EPIGENETIC MODIFICATION, ULTIMATELY LEADING TO THE FORMATION OF AS. CIRCRNAS CAN BE USED AS PERIPHERAL BLOOD MARKERS OF AS, AND PLAY AN IMPORTANT REGULATORY ROLE IN THE PROLIFERATION, MIGRATION, INFLAMMATION AND APOPTOSIS OF VASCULAR SMOOTH MUSCLE CELLS, ENDOTHELIAL CELLS AND MACROPHAGE, WHICH ARE KEY CELLS FOR THE DEVELOPMENT OF AS. THE IN-DEPTH UNDERSTANDING OF CIRCRNAS IN AS NOT ONLY PROVIDES A NEW METHOD FOR THE DIAGNOSIS OF AS, BUT ALSO PROVIDES A NEW IDEA FOR THE TREATMENT OF AS. 2023 5 4228 30 METHYLATION OF INFLAMMATORY CELLS IN LUNG DISEASES. THIS CHAPTER OVERVIEWS ROLES OF DNA METHYLATION IN INFLAMMATORY CELL BIOLOGY WITH THE FOCUSES ON LYMPHOCYTES AND MACROPHAGES/MONOCYTES IN LUNG DISEASES, ALTHOUGH THE MOLECULAR MECHANISMS BY WHICH TARGET GENES ARE METHYLATED AND REGULATED IN LUNG DISEASES REMAIN UNCLEAR. MOST OF EPIGENETIC STUDIES ON DNA METHYLATION OF TARGET GENES IN LUNG DISEASES MAINLY DEMONSTRATED THE CORRELATION OF DNA METHYLATION OF TARGET GENES WITH THE LEVELS OF OTHER CORRESPONDING FACTORS, WITH THE SPECIFICITY OF CLINICAL PHENOMES, AND WITH THE SEVERITY OF LUNG DISEASES. THERE IS AN URGENT NEED TO IDENTIFY AND VALIDATE THE SPECIFICITY AND REGULATORY MECHANISMS OF INFLAMMATORY CELL EPIGENETICS IN DEPTH. THE EPIGENETIC HETEROGENEITY AMONG DIFFERENT SUBSETS OF T CELLS AND AMONG PROMOTERS OR NON-PROMOTERS OF TARGET GENES SHOULD BE FURTHERMORE CLARIFIED IN ACUTE OR CHRONIC LUNG DISEASES AND CANCERS. THE HYPER/HYPO-METHYLATION AND MODIFICATIONS OF CHROMOSOL AND EXTRACHROMOSOMAL DNA MAY RESULT IN ALTERNATIONS IN PROTEINS WITHIN INFLAMMATORY CELLS, WHICH CAN BE IDENTIFIED AS DISEASE-SPECIFIC BIOMARKERS AND THERAPEUTIC TARGETS. 2020 6 4285 35 MICRORNA EPIGENETIC SIGNATURES IN HUMAN DISEASE. MICRORNAS (MIRNAS) ARE SHORT NON-CODING RNAS THAT ACT AS IMPORTANT REGULATORS OF GENE EXPRESSION AS PART OF THE EPIGENETIC MACHINERY. IN ADDITION TO POSTTRANSCRIPTIONAL GENE SILENCING BY MIRNAS, THE EPIGENETIC MECHANISMS ALSO INCLUDE DNA METHYLATION, HISTONE MODIFICATIONS AND THEIR CROSSTALK. EPIGENETIC MODIFICATIONS WERE REPORTED TO PLAY AN IMPORTANT ROLE IN MANY DISEASE ONSETS AND PROGRESSIONS AND CAN BE USED TO EXPLAIN SEVERAL FEATURES OF COMPLEX DISEASES, SUCH AS LATE ONSET AND FLUCTUATION OF SYMPTOMS. HOWEVER, MIRNAS NOT ONLY FUNCTION AS A PART OF EPIGENETIC MACHINERY, BUT ARE ALSO EPIGENETICALLY MODIFIED BY DNA METHYLATION AND HISTONE MODIFICATION LIKE ANY OTHER PROTEIN-CODING GENE. THERE IS A STRONG CONNECTION BETWEEN EPIGENOME AND MIRNOME, AND ANY DYSREGULATION OF THIS COMPLEX SYSTEM CAN RESULT IN VARIOUS PHYSIOLOGICAL AND PATHOLOGICAL CONDITIONS. IN ADDITION, MIRNAS PLAY AN IMPORTANT ROLE IN TOXICOGENOMICS AND MAY EXPLAIN THE RELATIONSHIP BETWEEN TOXICANT EXPOSURE AND TUMORIGENESIS. THE PRESENT REVIEW PROVIDES INFORMATION ON 63 MIRNA GENES SHOWN TO BE EPIGENETICALLY REGULATED IN ASSOCIATION WITH 21 DISEASES, INCLUDING 11 CANCER TYPES: CARDIAC FIBROSIS, CARDIOVASCULAR DISEASE, PREECLAMPSIA, HIRSCHSPRUNG'S DISEASE, RHEUMATOID ARTHRITIS, SYSTEMIC SCLEROSIS, SYSTEMIC LUPUS ERYTHEMATOSUS, TEMPORAL LOBE EPILEPSY, AUTISM, PULMONARY FIBROSIS, MELANOMA, ACUTE MYELOID LEUKEMIA, CHRONIC LYMPHOCYTIC LEUKEMIA, COLORECTAL, GASTRIC, CERVICAL, OVARIAN, PROSTATE, LUNG, BREAST, AND BLADDER CANCER. THE REVIEW REVEALED THAT HSA-MIR-34A, HSA-MIR-34B, AND HSA-MIR-34C ARE THE MOST FREQUENTLY REPORTED EPIGENETICALLY DYSREGULATED MIRNAS. THERE IS A NEED TO FURTHER STUDY MOLECULAR MECHANISMS OF VARIOUS DISEASES TO BETTER UNDERSTAND THE CROSSTALK BETWEEN EPIGENETICS AND GENE EXPRESSION AND TO DEVELOP NEW THERAPEUTIC OPTIONS AND BIOMARKERS. 2016 7 3503 33 IDENTIFICATION OF POTENTIAL DIFFERENTIALLY METHYLATED GENE-RELATED BIOMARKERS IN ENDOMETRIOSIS. AIM: TO IDENTIFY EPIGENETIC ALTERATIONS OF DIFFERENTIALLY EXPRESSED GENES AND SCREEN OUT TARGETED THERAPEUTIC DRUGS IN ENDOMETRIOSIS. METHODS: BASED ON THE GENE EXPRESSION OMNIBUS DATABASE AND A SERIES OF BIOLOGICAL INFORMATION ANALYSIS TOOLS, SUPPLEMENTED BY VALIDATION OF CLINICAL SAMPLES, ABERRANT DNA METHYLATION-DRIVEN GENES AND THEIR FUNCTIONS WERE EXPLORED, AS WELL AS POSSIBLE TARGETED DRUGS. RESULTS: THIS STUDY SCREENED OUT A RANGE OF DNA METHYLATION-DRIVEN GENES THAT WERE ASSOCIATED WITH POWERFUL PROPERTIES AND CORRESPONDING PATHWAYS. AMONG THEM, BDNF AND CCL2 WERE KEY GENES IN THE DEVELOPMENT OF ENDOMETRIOSIS. FOUR CHEMICAL AGENTS HAVE BEEN FLAGGED AS POTENTIAL TREATMENTS FOR ENDOMETRIOSIS. CONCLUSION: THESE CANDIDATE GENES AND SMALL-MOLECULE AGENTS MAY BE FURTHER EXPLORED AS POTENTIAL TARGETS AND DRUGS FOR ENDOMETRIOSIS DIAGNOSIS AND THERAPY, RESPECTIVELY. 2022 8 3772 31 INTERACTION BETWEEN MICRORNA AND DNA METHYLATION IN ATHEROSCLEROSIS. ATHEROSCLEROSIS (AS) IS A CHRONIC INFLAMMATORY DISEASE ACCOMPANIED BY COMPLEX PATHOLOGICAL CHANGES, SUCH AS ENDOTHELIAL DYSFUNCTION, FOAM CELL FORMATION, AND VASCULAR SMOOTH MUSCLE CELL PROLIFERATION. MANY APPROACHES, INCLUDING REGULATING AS-RELATED GENE EXPRESSION IN THE TRANSCRIPTIONAL OR POST-TRANSCRIPTIONAL LEVEL, CONTRIBUTE TO ALLEVIATING AS DEVELOPMENT. THE DNA METHYLATION IS A CRUCIAL EPIGENETIC MODIFICATION IN REGULATING CELL FUNCTION BY SILENCING THE RELATIVE GENE EXPRESSION. THE MICRORNA (MIRNA) IS A TYPE OF NONCODING RNA THAT PLAYS AN IMPORTANT ROLE IN GENE POST-TRANSCRIPTIONAL REGULATION AND DISEASE DEVELOPMENT. THE DNA METHYLATION AND THE MIRNA ARE IMPORTANT EPIGENETIC FACTORS IN AS. HOWEVER, RECENT STUDIES HAVE FOUND A MUTUAL REGULATION BETWEEN THESE TWO FACTORS IN AS DEVELOPMENT. IN THIS STUDY, RECENT INSIGHTS INTO THE ROLES OF MIRNA AND DNA METHYLATION AND THEIR INTERACTION IN THE AS PROGRESSION ARE REVIEWED. 2021 9 1019 31 CIRCRNA-MIRNA CROSS-TALK IN THE TRANSITION FROM PAROXYSMAL TO PERMANENT ATRIAL FIBRILLATION. BACKGROUND: ATRIAL FIBRILLATION (AF) IS THE MOST PREVALENT CARDIAC ARRHYTHMIA IN WESTERN COUNTRIES. THE FACTORS GOVERNING THE PROGRESSION OF AF TO A PERMANENT CHRONIC CONDITION ARE STILL NOT WELL CHARACTERIZED. AMONG EPIGENETIC FACTORS, NON-CODING RNAS (NCRNAS) SUCH AS MIRNAS AND LNCRNAS HAVE BEEN RECENTLY DESCRIBED AS IMPORTANT PLAYERS INVOLVED IN THE AF PROGRESSION. WE HYPOTHESIZE ABOUT THE EXISTENCE OF ADDITIONAL REGULATORY LAYERS IN AF INVOLVING AN INTRICATE CROSS-TALK BETWEEN DIFFERENT NCRNA SPECIES, NAMELY MIRNAS AND CIRCRNAS FOR THE ESTABLISHMENT OF A CHRONIC AF CONDITION. METHODS AND RESULTS: WE HAVE PERFORMED AN UNBIASED STUDY ANALYZING THE EXPRESSION PROFILE FOR MIRNAS AND CIRCRNAS IN LEFT-ATRIAL BIOPSIES FROM PATIENTS WITH PAROXYSMAL AND PERMANENT AF BY RNA-SEQ. THE TRANSITION FROM PAROXYSMAL TO PERMANENT AF IS CHARACTERIZED BY A PATTERN OF DOWN-REGULATED MIRNAS, CONCOMITANT TO THE APPEARANCE OF SPECIFIC CIRCRNA SPECIES. THE ANALYSIS OF THE SPONGING ACTIVITIES OF THE CIRCRNAS EXCLUSIVELY EXPRESSED IN PERMANENT AF SAMPLES, ALLOWED US TO DETERMINE THAT THEY COULD BE RESPONSIBLE FOR THE DOWNREGULATION OF SPECIFIC MIRNAS IN ESTABLISHMENT OF A PERMANENT AF CONDITION. CONCLUSION: SPONGING ACTIVITY OF CIRCRNAS SEQUESTERING SPECIFIC MIRNAS IS AN IMPORTANT FACTOR TO BE CONSIDERED FOR THE DETERMINATION OF THE MOLECULAR MECHANISMS INVOLVED IN AF PROGRESSION. 2019 10 5495 43 REVIEW ON CIRCULAR RNAS AND NEW INSIGHTS INTO THEIR ROLES IN CANCER. CIRCULAR RNAS (CIRCRNAS) ARE A VERY INTERESTING CLASS OF CONSERVED SINGLE-STRANDED RNA MOLECULES DERIVED FROM EXONIC OR INTRONIC SEQUENCES BY PRECURSOR MRNA BACK-SPLICING. UNLIKE CANONICAL LINEAR RNAS, CIRCRNAS FORM COVALENTLY CLOSED, CONTINUOUS STABLE LOOPS WITHOUT A 5'END CAP AND 3'END POLY(A) TAIL, AND THEREFORE ARE RESISTANT TO EXONUCLEASE DIGESTION. THE MAJORITY OF CIRCRNAS ARE HIGHLY ABUNDANT, AND CONSERVED ACROSS DIFFERENT SPECIES WITH A TISSUE OR DEVELOPMENTAL-STAGE-SPECIFIC EXPRESSION. CIRCRNAS HAVE BEEN SHOWN TO PLAY IMPORTANT ROLES AS MICRORNA SPONGES, REGULATORS OF GENE SPLICING AND TRANSCRIPTION, RNA-BINDING PROTEIN SPONGES AND PROTEIN/PEPTIDE TRANSLATORS. EMERGING EVIDENCE REVEALS THAT CIRCRNAS FUNCTION IN VARIOUS HUMAN DISEASES, PARTICULARLY CANCERS, AND MAY FUNCTION AS BETTER PREDICTIVE BIOMARKERS AND THERAPEUTIC TARGETS FOR CANCER TREATMENT. IN CONSIDERATION OF THEIR POTENTIAL CLINICAL RELEVANCE, CIRCRNAS HAVE BECOME A NEW RESEARCH HOTSPOT IN THE FIELD OF TUMOR PATHOLOGY. IN THE PRESENT STUDY, THE CURRENT UNDERSTANDING OF THE BIOGENESIS, CHARACTERISTICS, DATABASES, RESEARCH METHODS, BIOLOGICAL FUNCTIONS SUBCELLULAR DISTRIBUTION, EPIGENETIC REGULATION, EXTRACELLULAR TRANSPORT AND DEGRADATION OF CIRCRNAS WAS DISCUSSED. IN PARTICULAR, THE MULTIPLE DATABASES AND METHODS INVOLVED IN CIRCRNA RESEARCH WERE FIRST SUMMARIZED, AND THE RECENT ADVANCES IN DETERMINING THE POTENTIAL ROLES OF CIRCRNAS IN TUMOR GROWTH, MIGRATION AND INVASION, WHICH RENDER CIRCRNAS BETTER PREDICTIVE BIOMARKERS, WERE DESCRIBED. FURTHERMORE, FUTURE PERSPECTIVES FOR THE CLINICAL APPLICATION OF CIRCRNAS IN THE MANAGEMENT OF PATIENTS WITH CANCER WERE PROPOSED, WHICH COULD PROVIDE NEW INSIGHTS INTO CIRCRNAS IN THE FUTURE. 2021 11 6371 37 THE ROLE OF MICRORNAS IN THE PATHOGENESIS AND TREATMENT OF HEMATOPOIETIC MALIGNANCIES. MICRORNAS (MIRNAS) COMPRISE A RECENTLY DISCOVERED CLASS OF NON-CODING RNAS WITH REGULATORY FUNCTIONS IN POST-TRANSCRIPTIONAL GENE EXPRESSION CONTROL. MANY MIRNAS ARE LOCATED IN GENOMIC REGIONS THAT ARE FREQUENTLY DELETED IN CANCER, OR ARE SUBJECT TO EPIGENETIC AND TRANSCRIPTIONAL DEREGULATION IN CANCER CELLS. THE MIRNA TRANSCRIPTOME OF CANCER CELLS IS VERY DIFFERENT FROM THAT OF THEIR NORMAL CELL COUNTERPARTS. MIRNAS CAN EXHIBIT ONCOGENIC OR TUMOR SUPPRESSIVE OR EVEN BOTH PROPERTIES DEPENDING ON THE SPECIFIC TARGETS AND CELLULAR CONTEXT. IT IS BECOMING INCREASINGLY CLEAR THAT MIRNAS NOT ONLY SERVE AS USEFUL TUMOR BIOMARKERS WITH IMPLICATIONS FOR DIAGNOSIS, PROGNOSIS AND THE PREDICTION OF TREATMENT RESPONSES, BUT MAY ALSO BE USED FOR TARGETED CANCER TREATMENT AND EVEN AS THERAPEUTICS. IN THIS REVIEW, WE PROVIDE AN OVERVIEW OF RECENT ADVANCES IN OUR UNDERSTANDING OF THE TUMOR SUPPRESSOR MIRNAS AND ONCOMIRS INVOLVED IN THE PATHOGENESIS OF LEUKEMIAS AND LYMPHOMAS, AND THEIR TARGET TRANSCRIPTS IN CANCER SIGNALING NETWORKS. IN PARTICULAR, WE FOCUS ON THE ROLE OF MIRNAS IN CHRONIC LYMPHOCYTIC AND ACUTE LYMPHOBLASTIC LEUKEMIA AND IN B-CELL LYMPHOMAS. IN THE SECOND PART, WE REVIEW THE VARIOUS ALTERNATIVE STRATEGIES OF TARGETING MIRNAS IN CANCER THERAPY. METHODS OF ONCOMIR ANTAGONIZATION BY ANTAGOMIRS OR LOCKED NUCLEID ACIDS ARE CONTRASTED WITH STRATEGIES THAT HARNESS THE TUMOR SUPPRESSIVE PROPERTIES OF CERTAIN MIRNAS FOR CANCER TREATMENT. PRECLINICAL PROGRESS, ALSO WITH REGARD TO DELIVERY STRATEGIES, POSSIBLE SIDE EFFECTS AND OTHER PHARMACOLOGICAL ASPECTS, IS PRESENTED ALONG WITH RESULTS FROM THE FIRST HUMAN TRIALS ASSESSING THE SAFETY AND EFFICACY OF MIRNA-TARGETING THERAPEUTICS. 2013 12 5256 43 PROGRESSES IN EPIGENETIC STUDIES OF ASTHMA FROM THE PERSPECTIVE OF HIGH-THROUGHPUT ANALYSIS TECHNOLOGIES: A NARRATIVE REVIEW. BACKGROUND AND OBJECTIVE: ASTHMA IS THE MOST COMMON CHRONIC RESPIRATORY DISEASE IN THE WORLD WITH AN ESTIMATED HERITABILITY BETWEEN 50% AND 60%, AND RECENT STUDIES HAVE SHOWN THAT EPIGENETIC MECHANISMS PLAY AN IMPORTANT ROLE IN ITS DEVELOPMENT. MANY CUTTING-EDGE EPIGENETIC RESEARCH TECHNIQUES HAVE BEEN APPLIED TO THE STUDY OF THE PATHOGENESIS OF ASTHMA, WHICH HAS PROMOTED THE DEVELOPMENT OF ASTHMA ETIOLOGY AND BROUGHT NEW POSSIBILITIES FOR TREATMENT. WE SUMMARIZED RECENT ADVANCES IN EPIGENETIC RESEARCH OF THE PATHOGENESIS OF ASTHMA, ESPECIALLY FROM THE PERSPECTIVE OF HIGH-THROUGHPUT ANALYSIS TECHNIQUES, TO FIND POTENTIAL EPIGENETIC BIOMARKERS AND POSSIBLE MOLECULAR TARGETS FOR THE FUTURE INTERVENTION AND TREATMENT OF THE DISEASE. METHODS: WE REVIEWED AND SUMMARIZED RECENT PROGRESS IN EPIGENOMIC STUDIES OF ASTHMA ON A "PRE-TRANSCRIPTIONAL LEVEL", INCLUDING DNA METHYLATION, HISTONE MODIFICATION, AND CHROMATIN REMODELING, AND ON A "POST-TRANSCRIPTIONAL LEVEL" WITH A FOCUS ON NON-CODING RNA, FROM THE PERSPECTIVE OF HIGH-THROUGHPUT ANALYSIS TECHNOLOGIES. KEY CONTENT AND FINDINGS: WE HAVE SUMMARIZED THE PROGRESS OF DIFFERENT KINDS OF RECENT EPIGENETIC STUDIES IN ASTHMA, INCLUDING DNA METHYLATION STUDIES [CANDIDATE GENES METHYLATION STUDIES AND EPIGENOME-WIDE ASSOCIATION STUDY (EWAS)], HISTONE MODIFICATION STUDIES (HISTONE ACETYLATION/DEACETYLATION STUDIES AND HISTONE METHYLATION STUDIES), NON-CODING RNA STUDIES [MICRORNAS (MIRNAS), LONG NON-CODING RNAS (LNCRNAS) AND CIRCULAR RNAS (CIRCRNAS)], TO HELP THE READERS TO GAIN A COMPREHENSIVE INSIGHT INTO THE EPIGENETIC RESEARCH FIELDS FOR ASTHMA. THE APPLICATION OF HIGH-THROUGHPUT ANALYSIS TECHNIQUES IN ASTHMA RESEARCH, INCLUDING EWAS (DNA METHYLATION CHIPS), CHROMATIN IMMUNOPRECIPITATION SEQUENCING (CHIP-SEQ), MICRORNA SEQUENCING, WHOLE TRANSCRIPTOME SEQUENCING, CO-EXPRESSION NETWORK AND COMPETING ENDOGENOUS RNA (CERNA) ANALYSES, WERE INTRODUCED ACCOMPANY WITH THE MAIN FINDINGS. AND THE POTENTIAL EPIGENETIC BIOMARKERS AND POSSIBLE MOLECULAR TARGETS IDENTIFIED VIA HIGH-THROUGHPUT ANALYSES WERE ALSO DISCUSSED. CONCLUSIONS: EPIGENETIC RESEARCH HAS BECOME A HOTSPOT IN RESEARCH ON THE PATHOGENESIS OF ASTHMA. THE COMBINATION OF HIGH-THROUGHPUT EPIGENETIC ANALYSIS TECHNOLOGIES AND TRADITIONAL BIOLOGICAL FUNCTION AND CLINICAL STUDIES WILL BRING NEW BREAKTHROUGH IN THE PATHOGENESIS STUDY OF ASTHMA, WHICH WILL IMPROVE THE GENETIC INTERPRETATION OF THE DISEASE AND BRING MORE POSSIBILITIES FOR THE DEVELOPMENT OF PRECISION MEDICINE TO TREAT IT. 2022 13 6092 31 THE EFFECTS OF EPIGENETIC MODIFICATION ON THE OCCURRENCE AND PROGRESSION OF LIVER DISEASES AND THE INVOLVED MECHANISM. INTRODUCTION: EPIGENETIC MODIFICATION IS A TYPE OF GENE EXPRESSION AND REGULATION THAT DOES NOT INVOLVE CHANGES IN DNA SEQUENCES. AN INCREASING NUMBER OF STUDIES HAVE PROVEN THAT EPIGENETIC MODIFICATIONS PLAY AN IMPORTANT ROLE IN THE OCCURRENCE AND PROGRESSION OF LIVER DISEASES THROUGH THE GENE REGULATION AND PROTEIN EXPRESSIONS OF HEPATOCELLULAR LIPID METABOLISM, INFLAMMATORY REACTION, CELL PROLIFERATION, AND ACTIVATION, ETC.AREAS COVERED: IN THIS STUDY, WE ELABORATED AND ANALYZED THE UNDERLYING FUNCTIONAL MECHANISM OF EPIGENETIC MODIFICATION IN ALCOHOLIC LIVER DISEASE (ALD), NONALCOHOLIC FATTY LIVER DISEASE (NAFLD), LIVER FIBROSIS (LF), VIRAL HEPATITIS, HEPATOCELLULAR CARCINOMA (HCC), AND RESEARCH PROGRESS OF RECENT YEARS.EXPERT OPINION: THE FURTHER UNDERSTANDING OF EPIGENETIC MECHANISMS THAT CAN REGULATE GENE EXPRESSION AND CELL PHENOTYPE LEADS TO NEW INSIGHTS IN EPIGENETIC CONTROL OF CHRONIC LIVER DISEASE. CURRENTLY, HEPATOLOGISTS ARE EXPLORING THE ROLE OF DNA METHYLATION, HISTONE/CHROMATIN MODIFICATION, AND NON-CODING RNA IN SPECIFIC LIVER PATHOLOGY. THESE FINDINGS HAVE LED TO ADVANCES IN DIRECT EPIGENETIC BIOMARKER TESTING OF PATIENT TISSUE OR BODY FLUID SPECIMENS, AS WELL AS QUANTITATIVE ANALYSIS. BASED ON THESE FINDINGS, DRUG VALIDATION OF SOME TARGETS INVOLVED IN THE EPIGENETIC MECHANISM OF LIVER DISEASE IS GRADUALLY BEING CARRIED OUT CLINICALLY. 2020 14 6431 33 THE USE OF TARGETED NEXT GENERATION SEQUENCING TO EXPLORE CANDIDATE REGULATORS OF TGF-BETA1'S IMPACT ON KIDNEY CELLS. AIMS/HYPOTHESIS: TRANSFORMING GROWTH FACTOR-BETA (TGF-BETA1) PLAYS AN IMPORTANT REGULATORY ROLE IN THE PROGRESSION OF CHRONIC KIDNEY FAILURE. FURTHER, DAMAGE TO KIDNEY GLOMERULAR MESANGIAL CELLS IS CENTRAL TO THE PROGRESSION OF DIABETIC NEPHROPATHY. THE AIM OF THIS STUDY WAS TO EXPLORE THE GENETIC ASSOCIATIONS BETWEEN MRNA, MICRORNA, AND EPIGENETICS IN MESANGIAL CELLS IN RESPONSE TO TGF-BETA1. METHODS: THE REGULATORY EFFECTS OF TGF-BETA1 ON MESANGIAL CELLS WERE INVESTIGATED AT DIFFERENT MOLECULAR LEVELS BY TREATING MESANGIAL CELLS WITH TGF-BETA1 FOR 3 DAYS FOLLOWED BY GENOME-WIDE MIRNA, RNA, DNA METHYLATION, AND H3K27ME3 EXPRESSION PROFILING USING NEXT GENERATION SEQUENCING (NGS). RESULTS: OUR RESULTS PROVIDE THE FIRST COMPREHENSIVE, COMPUTATIONALLY INTEGRATED REPORT OF RNA-SEQ, MIRNA-SEQ, AND EPIGENOMIC ANALYSES ACROSS ALL GENETIC VARIATIONS, CONFIRMING THE OCCURRENCE OF DNA METHYLATION AND H3K27ME3 IN RESPONSE TO TGF-BETA1. OUR FINDINGS SHOW THAT THE EXPRESSION OF KLF7 AND GJA4 ARE INVOLVED IN TGF-BETA1 REGULATED DNA METHYLATION. OUR DATA ALSO PROVIDE EVIDENCE OF THE ASSOCIATION BETWEEN EPIGENETIC CHANGES AND THE EXPRESSION OF GENES CLOSELY RELATED TO TGF-BETA1 REGULATION. CONCLUSION: THIS STUDY HAS ADVANCED OUR CURRENT KNOWLEDGE OF MECHANISMS THAT CONTRIBUTE TO THE EXPRESSION OF TGF-BETA1-REGULATED GENES INVOLVED IN THE PATHOGENESIS OF KIDNEY DISEASE. THE MOLECULAR UNDERPINNINGS OF TGF-BETA1 STIMULATION OF KIDNEY CELLS WAS DETERMINED, THEREBY PROVIDING A ROBUST PLATFORM FOR FURTHER TARGET EXPLORATION. 2018 15 4289 33 MICRORNA IN OSTEOARTHRITIS. OSTEOARTHRITIS (OA) IS THE MOST PREVALENT DEGENERATIVE JOINT DISEASE AND IS ACCOMPANIED BY PAIN AND JOINT DYSFUNCTION. ITS CLINICAL TREATMENT TENDS TO BE UNSATISFACTORY. NOVEL TARGETS IN OA INCLUDE GENES THAT ARE INVOLVED IN OA PATHOPHYSIOLOGY AND HAVE BEEN DISCOVERED USING GENE NETWORK, EPIGENETIC AND MICRORNA (MIRNA) APPROACHES. MIRNA HAS BEEN IMPLICATED IN IMPORTANT CELLULAR PROCESSES SUCH AS LIPID METABOLISM, APOPTOSIS, DIFFERENTIATION AND ORGAN DEVELOPMENT. THE IMPORTANCE OF MIRNA REGULATION IN CELLULAR FUNCTION IS BECOMING INCREASINGLY CLEAR AS NEW MIRNA TARGETS ARE REVEALED. THE PRESENT REVIEW SUMMARIZES THE CURRENT EVIDENCE OF THE IMPORTANT ROLE PLAYED BY MIRNA IN DETERMINING THE COMPLEX GENE EXPRESSION PATTERNS OF OA CHONDROCYTES AND THEIR ROLE IN THE REGULATION OF TRANSCRIPTION, AND POSSIBLE DEMETHYLATION MECHANISMS THAT MIGHT BE APPLICABLE IN OA. IN SUMMARY, MIRNA MAY HAVE IMPORTANT DIAGNOSTIC AND THERAPEUTIC POTENTIAL, AND MIGHT PROVIDE A NOVEL MEANS OF TREATING OA. 2011 16 1518 30 DNA METHYLATION AS AN EPIGENETIC MECHANISM IN THE DEVELOPMENT OF MULTIPLE SCLEROSIS. THE EPIGENETIC MECHANISMS OF GENE EXPRESSION REGULATION ARE A GROUP OF THE KEY CELLULAR AND MOLECULAR PATHWAYS THAT LEAD TO INHERITED ALTERATIONS IN GENES' ACTIVITY WITHOUT CHANGING THEIR CODING SEQUENCE. DNA METHYLATION AT THE C5 POSITION OF CYTOSINE IN CPG DINUCLEOTIDES IS AMONGST THE CENTRAL EPIGENETIC MECHANISMS. CURRENTLY, THE NUMBER OF STUDIES THAT ARE DEVOTED TO THE IDENTIFICATION OF METHYLATION PATTERNS SPECIFIC TO MULTIPLE SCLEROSIS (MS), A SEVERE CHRONIC AUTOIMMUNE DISEASE OF THE CENTRAL NERVOUS SYSTEM, IS ON A RAPID RISE. HOWEVER, THE ISSUE OF THE CONTRIBUTION OF DNA METHYLATION TO THE DEVELOPMENT OF THE DIFFERENT CLINICAL PHENOTYPES OF THIS HIGHLY HETEROGENEOUS DISEASE HAS ONLY BEGUN TO ATTRACT THE ATTENTION OF RESEARCHERS. THIS REVIEW SUMMARIZES THE DATA ON THE MOLECULAR MECHANISMS UNDERLYING DNA METHYLATION AND THE MS RISK FACTORS THAT CAN AFFECT THE DNA METHYLATION PROFILE AND, THEREBY, MODULATE THE EXPRESSION OF THE GENES INVOLVED IN THE DISEASE'S PATHOGENESIS. THE FOCUS OF OUR ATTENTION IS CENTERED ON THE ANALYSIS OF THE PUBLISHED DATA ON THE DIFFERENTIAL METHYLATION OF DNA FROM VARIOUS BIOLOGICAL SAMPLES OF MS PATIENTS OBTAINED USING BOTH THE CANDIDATE GENE APPROACH AND HIGH-THROUGHPUT METHODS. 2021 17 4961 33 PATHOGENESIS OF PSORIASIS IN THE "OMIC" ERA. PART II. GENETIC, GENOMIC AND EPIGENETIC CHANGES IN PSORIASIS. PSORIASIS IS A MULTIFACTORIAL DISEASE IN WHICH GENETIC, ENVIRONMENTAL AND EPIGENETIC FACTORS REGULATING GENE EXPRESSION PLAY A KEY ROLE. IN THE "GENOMIC ERA", GENOME-WIDE ASSOCIATION STUDIES TOGETHER WITH TARGET GENOTYPING PLATFORMS PERFORMED IN DIFFERENT ETHNIC POPULATIONS HAVE FOUND MORE THAN 50 GENETIC SUSCEPTIBLE MARKERS ASSOCIATED WITH THE RISK OF PSORIASIS WHICH HAVE BEEN IDENTIFIED SO FAR. UP TILL NOW, THE STRONGEST ASSOCIATION WITH THE RISK OF THE DISEASE HAS BEEN PROVED FOR HLA-C*06 GENE. THE MAJORITY OF OTHER PSORIASIS RISK SNPS ARE SITUATED NEAR THE GENES ENCODING MOLECULES INVOLVED IN ADAPTIVE AND INNATE IMMUNITY, AND SKIN BARRIER FUNCTION. MANY CONTEMPORARY STUDIES INDICATE THAT THE EPIGENETIC CHANGES: HISTONE MODIFICATION, PROMOTER METHYLATIONS, LONG NON-CODING AND MICRO-RNA HYPEREXPRESSION ARE CONSIDERED AS FACTORS CONTRIBUTING TO PSORIASIS PATHOGENESIS AS THEY REGULATE ABNORMAL KERATINOCYTE DIFFERENTIATION AND PROLIFERATION, ABERRANT KERATINOCYTES - INFLAMMATORY CELLS COMMUNICATION, NEOANGIOGENESIS AND CHRONIC INFLAMMATION. THE CIRCULATING MIRNAS DETECTED IN THE BLOOD MAY BECOME SPECIFIC MARKERS IN THE DIAGNOSIS, PROGNOSIS AND RESPONSE TO THE TREATMENT OF THE DISEASE. THE INHIBITION OF EXPRESSION IN SELECTED MIRNAS MAY BE A NEW PROMISING THERAPY OPTION FOR PATIENTS WITH PSORIASIS. 2020 18 5120 39 POSSIBLE EPIGENETIC REGULATORY EFFECT OF DYSREGULATED CIRCULAR RNAS IN EPILEPSY. CIRCULAR RNAS (CIRCRNAS) INVOLVE IN THE EPIGENETIC REGULATION AND ITS MAJOR MECHANISM IS THE SEQUESTRATION OF THE TARGET MICRO RNAS (MIRNAS). WE HYPOTHESIZED THAT CIRCRNAS MIGHT BE RELATED WITH THE PATHOPHYSIOLOGY OF CHRONIC EPILEPSY AND EVALUATED THE ALTERED CIRCRNA EXPRESSIONS AND THEIR POSSIBLE REGULATORY EFFECTS ON THEIR TARGET MIRNAS AND MRNAS IN A MOUSE EPILEPSY MODEL. THE CIRCRNA EXPRESSION PROFILE IN THE HIPPOCAMPUS OF THE PILOCARPINE MICE WAS ANALYZED AND COMPARED WITH CONTROL. THE CORRELATION BETWEEN THE EXPRESSION OF MIRNA BINDING SITES (MIRNA RESPONSE ELEMENTS, MRE) IN THE DYSREGULATED CIRCRNAS AND THE EXPRESSION OF THEIR TARGET MIRNAS WAS EVALUATED. AS MIRNAS ALSO INHIBIT THEIR TARGET MRNAS, CIRCRNA-MIRNA-MRNA REGULATORY NETWORK, COMPRISED OF DYSREGULATED RNAS THAT TARGETS ONE ANOTHER WERE SEARCHED. FOR THE IDENTIFIED NETWORKS, BIOINFORMATICS ANALYSES WERE PERFORMED. AS THE RESULT, FORTY-THREE CIRCRNAS WERE DYSREGULATED IN THE HIPPOCAMPUS (UP-REGULATED, 26; DOWN-REGULATED, 17). THE CHANGE IN THE EXPRESSION OF MRE IN THOSE CIRCRNAS NEGATIVELY CORRELATED WITH THE CHANGE IN THE RELEVANT TARGET MIRNA EXPRESSION (R = -0.461, P<0.001), SUPPORTING THAT CIRCRNAS INHIBIT THEIR TARGET MIRNA. 333 DYSREGULATED CIRCRNA-MIRNA-MRNA NETWORKS WERE IDENTIFIED. GENE ONTOLOGY AND PATHWAY ANALYSES DEMONSTRATED THAT THE UP-REGULATED MRNAS IN THOSE NETWORKS WERE CLOSELY RELATED TO THE MAJOR PROCESSES IN EPILEPSY. AMONG THEM, STRING ANALYSIS IDENTIFIED 37 KEY MRNAS WITH ABUNDANT (>/=4) INTERACTIONS WITH OTHER DYSREGULATED TARGET MRNAS. THE DYSREGULATION OF THE CIRCRNAS WHICH HAD MULTIPLE INTERACTIONS WITH KEY MRNAS WERE VALIDATED BY PCR. WE CONCLUDED THAT DYSREGULATED CIRCRNAS MIGHT HAVE A PATHOPHYSIOLOGIC ROLE IN CHRONIC EPILEPSY BY REGULATING MULTIPLE DISEASE RELEVANT MRNAS VIA CIRCRNA-MIRNA-MRNA INTERACTIONS. 2018 19 4335 38 MICRORNAS: SMALL MOLECULES WITH SIGNIFICANT FUNCTIONS, PARTICULARLY IN THE CONTEXT OF VIRAL HEPATITIS B AND C INFECTION. A MICRORNA (MIRNA) IS DEFINED AS A SMALL MOLECULE OF NON-CODING RNA (NCRNA). ITS MOLECULAR SIZE IS ABOUT 20 NUCLEOTIDES (NT), AND IT ACTS ON GENE EXPRESSION'S REGULATION AT THE POST-TRANSCRIPTION LEVEL THROUGH BINDING TO THE 3'UNTRANSLATED REGIONS (UTR), CODING SEQUENCES, OR 5'UTR OF THE TARGET MESSENGER RNAS (MRNAS), WHICH LEADS TO THE SUPPRESSION OR DEGRADATION OF THE MRNA. IN RECENT YEARS, A HUGE EVOLUTION HAS IDENTIFIED THE ORIGIN AND FUNCTION OF MIRNAS, FOCUSING ON THEIR IMPORTANT EFFECTS IN RESEARCH AND CLINICAL APPLICATIONS. FOR EXAMPLE, MICRORNAS ARE KEY PLAYERS IN HCV INFECTION AND HAVE IMPORTANT HOST CELLULAR FACTORS REQUIRED FOR HCV REPLICATION AND CELL GROWTH. ALTERED EXPRESSION OF MIRNAS AFFECTS THE PATHOGENICITY ASSOCIATED WITH HCV INFECTION THROUGH REGULATING DIFFERENT SIGNALING PATHWAYS THAT CONTROL HCV/IMMUNITY INTERACTIONS, PROLIFERATION, AND CELL DEATH. ON THE OTHER HAND, CIRCULATING MIRNAS CAN BE USED AS NOVEL BIOMARKERS AND DIAGNOSTIC TOOLS FOR HCV PATHOGENESIS AND EARLY THERAPEUTIC RESPONSE. MOREOVER, MICRORNAS (MIRNA) HAVE BEEN INVOLVED IN HEPATITIS B VIRUS (HBV) GENE EXPRESSION AND ADVANCED ANTIVIRAL DISCOVERY. THEY REGULATE HBV/HCV REPLICATION AND PATHOGENESIS WITH DIFFERENT PATHWAYS INVOLVING FACILITATION, INHIBITION, ACTIVATION OF THE IMMUNE SYSTEM (INNATE AND ADAPTIVE), AND EPIGENETIC MODIFICATIONS. IN THIS SHORT REVIEW, WE WILL DISCUSS HOW MICRORNAS CAN BE USED AS PROGNOSTIC, DIAGNOSTIC, AND THERAPEUTIC TOOLS, ESPECIALLY FOR CHRONIC HEPATITIS VIRUSES (HBV AND HCV), AS WELL AS HOW THEY COULD BE USED AS NEW BIOMARKERS DURING INFECTION AND ADVANCED TREATMENT. 2023 20 416 31 ANALYSIS OF THE DYNAMIC ABERRANT LANDSCAPE OF DNA METHYLATION AND GENE EXPRESSION DURING ARSENIC-INDUCED CELL TRANSFORMATION. INORGANIC ARSENIC IS A WELL-KNOWN CARCINOGEN ASSOCIATED WITH SEVERAL TYPES OF CANCER, BUT THE MECHANISMS INVOLVED IN ARSENIC-INDUCED CARCINOGENESIS ARE NOT FULLY UNDERSTOOD. RECENT EVIDENCE POINTS TO EPIGENETIC DYSREGULATION AS AN IMPORTANT MECHANISM IN THIS PROCESS; HOWEVER, THE EFFECTS OF EPIGENETIC ALTERATIONS IN GENE EXPRESSION HAVE NOT BEEN EXPLORED IN DEPTH. USING MICROARRAY DATA AND APPLYING A MULTIVARIATE CLUSTERING ANALYSIS IN A GAUSSIAN MIXTURE MODEL, WE DESCRIBE THE ALTERATIONS IN DNA METHYLATION AROUND THE PROMOTER REGION AND THE IMPACT ON GENE EXPRESSION IN HACAT CELLS DURING THE TRANSFORMATION PROCESS CAUSED BY CHRONIC EXPOSURE TO ARSENIC. USING THIS CLUSTERING APPROACH, THE GENES WERE GROUPED ACCORDING TO THEIR METHYLATION AND EXPRESSION STATUS IN THE EPIGENETIC LANDSCAPE, AND THE CHANGES THAT OCCURRED DURING THE CELLULAR TRANSFORMATION WERE IDENTIFIED ADEQUATELY. THUS, WE PRESENT A VALUABLE METHOD FOR IDENTIFYING EPIGENOMIC DYSREGULATION. 2019