title: Analysis of Deregulated microRNAs and Their Target Genes in Gastric Cancer.
abstract: BACKGROUND
  MicroRNAs (miRNAs) are widely studied non-coding RNAs that modulate gene expression. MiRNAs are deregulated in different tumors including gastric cancer (GC) and have potential diagnostic and prognostic implications. The aim of our study was to determine miRNA profile in GC tissues, followed by evaluation of deregulated miRNAs in plasma of GC patients. Using available databases and bioinformatics methods we also aimed to evaluate potential target genes of confirmed differentially expressed miRNA and validate these findings in GC tissues.
  
  
  METHODS
  The study included 51 GC patients and 51 controls. Initially, we screened miRNA expression profile in 13 tissue samples of GC and 12 normal gastric tissues with TaqMan low density array (TLDA). In the second stage, differentially expressed miRNAs were validated in a replication cohort using qRT-PCR in tissue and plasma samples. Subsequently, we analyzed potential target genes of deregulated miRNAs using bioinformatics approach, determined their expression in GC tissues and performed correlation analysis with targeting miRNAs.
  
  
  RESULTS
  Profiling with TLDA revealed 15 deregulated miRNAs in GC tissues compared to normal gastric mucosa. Replication analysis confirmed that miR-148a-3p, miR-204-5p, miR-223-3p and miR-375 were consistently deregulated in GC tissues. Analysis of GC patients' plasma samples showed significant down-regulation of miR-148a-3p, miR-375 and up-regulation of miR-223-3p compared to healthy subjects. Further, using bioinformatic tools we identified targets of replicated miRNAs and performed disease-associated gene enrichment analysis. Ultimately, we evaluated potential target gene BCL2 and DNMT3B expression by qRT-PCR in GC tissue, which correlated with targeting miRNA expression.
  
  
  CONCLUSIONS
  Our study revealed miRNA profile in GC tissues and showed that miR-148a-3p, miR-223-3p and miR-375 are deregulated in GC plasma samples, but these circulating miRNAs showed relatively weak diagnostic performance as sole biomarkers. Target gene analysis demonstrated that BCL2 and DNMT3B expression in GC tissue correlated with their targeting miRNA expression.
authors.affiliation: Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Simonas
authors.initials: S
authors.lastname: Juzėnas
authors.affiliation: Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Violeta
authors.initials: V
authors.lastname: Saltenienė
authors.affiliation: Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Juozas
authors.initials: J
authors.lastname: Kupcinskas
authors.affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Link
authors.affiliation: Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Gediminas
authors.initials: G
authors.lastname: Kiudelis
authors.affiliation: Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Laimas
authors.initials: L
authors.lastname: Jonaitis
authors.affiliation: Division of Human Genome Research Centre, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania.
authors.forename: Sonata
authors.initials: S
authors.lastname: Jarmalaite
authors.affiliation: Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Limas
authors.initials: L
authors.lastname: Kupcinskas
authors.affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Malfertheiner
authors.affiliation: Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Jurgita
authors.initials: J
authors.lastname: Skieceviciene
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics*; D016022:Case-Control Studies; D019295:Computational Biology; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D052138:Genes, Neoplasm / Q000235:genetics*; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000097:blood / Q000235:genetics*; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D013274:Stomach Neoplasms / Q000097:blood / Q000235:genetics*; D000097584:DNA Methyltransferase 3B
chemical_list: D014408:Biomarkers, Tumor; D004248:DNA (Cytosine-5-)-Methyltransferases; D035683:MicroRNAs; D019253:Proto-Oncogene Proteins c-bcl-2; D000097584:DNA Methyltransferase 3B; C000595707:BCL2 protein, human