title: miR-101-2, miR-125b-2 and miR-451a act as potential tumor suppressors in gastric cancer through regulation of the PI3K/AKT/mTOR pathway.
abstract: BACKGROUND
  Gastric cancer (GC) is a deadly malignancy worldwide. In the past, it has been shown that cellular signaling pathway alterations play a crucial role in the development of GC. In particular, deregulation of the PI3K/AKT/mTOR pathway seems to affect multiple GC functions including growth, proliferation, metabolism, motility and angiogenesis. Targeting alterations in this pathway by microRNAs (miRNAs) represents a potential therapeutic strategy, especially in inhibitor-resistant tumors. The objective of this study was to evaluate the expression of 3 pre-selected miRNAs, miR-101-2, miR-125b-2 and miR-451a, in a series of primary GC tissues and matched non-GC tissues and in several GC-derived cell lines, and to subsequently evaluate the functional role of these miRNAs.
  
  
  METHODS
  Twenty-five primary GC samples, 25 matched non-GC samples and 3 GC-derived cell lines, i.e., AGS, MKN28 and MKN45, were included in this study. miRNA and target gene expression levels were assessed by quantitative RT-PCR and western blotting, respectively. Subsequently, cell viability, clone formation, cell death, migration and invasion assays were performed on AGS cells.
  
  
  RESULTS
  miR-101-2, miR-125b-2 and miR-451a were found to be down-regulated in the primary GC tissues and the GC-derived cell lines tested. MiRNA mimic transfections significantly reduced cell viability and colony formation, increased cell death and reduced cell migration and invasion in AGS cells. We also found that exogenous expression of miR-101-2, miR-125b-2 and miR-451a decreased the expression of their putative targets MTOR, PIK3CB and TSC1, respectively.
  
  
  CONCLUSIONS
  Our expression analyses and in vitro functional assays suggest that miR-101-2, miR-125b-2 and miR-451a act as potential tumor suppressors in primary GCs as well as in GC-derived AGS cells.
authors.affiliation: Laboratory of Molecular Pathology, Pathology Department, School of Medicine, BIOREN-CEGIN, Universidad de La Frontera, Avenida Alemania 0458, 4810296 Temuco, Chile.
authors.forename: Ismael
authors.initials: I
authors.lastname: Riquelme
authors.affiliation: Laboratory of Molecular Pathology, Pathology Department, School of Medicine, BIOREN-CEGIN, Universidad de La Frontera, Avenida Alemania 0458, 4810296 Temuco, Chile.
authors.forename: Oscar
authors.initials: O
authors.lastname: Tapia
authors.affiliation: Molecular Biology and Biomedicine Lab, CEGIN-BIOREN, Universidad de La Frontera, Avenida Alemania 0458, 4810296 Temuco, Chile.
authors.forename: Pamela
authors.initials: P
authors.lastname: Leal
authors.affiliation: Laboratory of Molecular Pathology, Pathology Department, School of Medicine, BIOREN-CEGIN, Universidad de La Frontera, Avenida Alemania 0458, 4810296 Temuco, Chile.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Sandoval
authors.affiliation: Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, 2215 Garland Avenue Nashville, 37232 Nashville, TN, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Varga
authors.affiliation: School of Health Sciences, Universidad Catolica de Temuco, Manuel Montt 56, 4813302 Temuco, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Letelier
authors.affiliation: Laboratory of Molecular Pathology, Pathology Department, School of Medicine, BIOREN-CEGIN, Universidad de La Frontera, Avenida Alemania 0458, 4810296 Temuco, Chile.
authors.forename: Kurt
authors.initials: K
authors.lastname: Buchegger
authors.affiliation: Department of Pathology, UC Centre for Investigational Oncology (CITO), Advanced Centre for Chronic Diseases (ACCDiS), School of Medicine, Pontificia Universidad Catolica de Chile, Marcoleta 377, 7th Floor, 8330024 Santiago, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Bizama
authors.affiliation: Department of Pathology, UC Centre for Investigational Oncology (CITO), Advanced Centre for Chronic Diseases (ACCDiS), School of Medicine, Pontificia Universidad Catolica de Chile, Marcoleta 377, 7th Floor, 8330024 Santiago, Chile.
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Espinoza
authors.affiliation: Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, 2215 Garland Avenue Nashville, 37232 Nashville, TN, USA.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Peek
authors.affiliation: Department of Pathology, School of Medicine, Universidad de La Frontera, Avenida Alemania 0458, 4810296 Temuco, Chile.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Araya
authors.affiliation: Department of Pathology, UC Centre for Investigational Oncology (CITO), Advanced Centre for Chronic Diseases (ACCDiS), School of Medicine, Pontificia Universidad Catolica de Chile, Marcoleta 377, 7th Floor, 8330024 Santiago, Chile.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Roa
mesh_terms: D001483:Base Sequence; D016923:Cell Death / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D058534:Class I Phosphatidylinositol 3-Kinases; D015536:Down-Regulation / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014162:Transfection; D000077004:Tuberous Sclerosis Complex 1 Protein; D014410:Tumor Stem Cell Assay; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D058534:Class I Phosphatidylinositol 3-Kinases; D035683:MicroRNAs; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D000077004:Tuberous Sclerosis Complex 1 Protein; D025521:Tumor Suppressor Proteins; C534072:MIRN101 microRNA, human; C531888:MIRN125 microRNA, human; C531201:MIRN451 microRNA, human; C000624650:TSC1 protein, human; C497132:PIK3CB protein, human
keywords: Gastric cancer; PI3K/AKT/mTOR pathway; miR-101-2; miR-125b-2; miR-451a; microRNAs