title: miR-34c-3p functions as a tumour suppressor by inhibiting eIF4E expression in non-small cell lung cancer.
abstract: OBJECTIVE
  MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression and mediate diverse physiological processes. In this study, we investigated functions of miRNA miR-34c-3p in non-small cell lung cancer (NSCLC).
  
  
  METHODS
  miR-34c-3p expression was evaluated by qPCR. Cell viability was examined by MTT and proliferation by cell cycle analysis. Cell migration and invasion were tested using Transwells with/without Matrigel coating. Western blot analysis was performed for eIF4E, c-Myc, Cyclin D1, survivin and Mcl-1 protein expression.
  
  
  RESULTS
  miR-34c-3p expression was significantly reduced in tissues and serum samples from NSCLC patients and in NSCLC cell lines A549, H460, H23, H157 and H1299. Overexpression of miR-34c-3p in A549 and H157 cells reduced cell proliferation, migration and invasion, whereas transfection with miR-34c-3p inhibitor (miR-34c-3p-in) produced opposite effects. Target analysis using algorithms miRanda, TargetScan and DIANA identified eIF4E as a potential target of miR-34c-3p. Luciferase assay using the eIF4E 3'-UTR reporter carrying a putative miR-34c-3p target sequence revealed eIF4E to be a specific target of miR-34c-3p. Overexpression of miR-34c-3p in NSCLS cell lines led to significant reduction in mRNA and protein levels of eIF4E, whereas inhibition of miR-34c-3p resulted in significant increase in eIf4e protein levels, confirming eIF4E to be a direct target of miR-34c-3p in NSCLS. Overexpression of eIF4E in A549 cells promoted cell proliferation, migration and invasion, which were partially reversed by miR-34c-3p.
  
  
  CONCLUSIONS
  miR-34c-3p directly targeted eIF4E and reduced miR-34c-3p expression in NSCLC, promoting cell cycle progression, proliferation, migration and invasion.
authors.affiliation: Department of Medical Oncology, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Thoracic Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Medical Imaging Division, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Jiebing
authors.initials: J
authors.lastname: Li
authors.affiliation: The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Kuo
authors.initials: K
authors.lastname: Gu
authors.affiliation: Department of Medical Oncology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Lv
authors.affiliation: Department of Medical Oncology, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Medical Oncology, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Dehai
authors.initials: D
authors.lastname: Che
authors.affiliation: Department of Medical Oncology, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Jingyan
authors.initials: J
authors.lastname: Cao
authors.affiliation: Department of Medical Oncology, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Shi
authors.initials: S
authors.lastname: Jin
authors.affiliation: Department of Medical Oncology, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yu
mesh_terms: D020413:3' Untranslated Regions; D001483:Base Sequence; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D015536:Down-Regulation / Q000235:genetics*; D039561:Eukaryotic Initiation Factor-4E / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D020413:3' Untranslated Regions; D039561:Eukaryotic Initiation Factor-4E; C522425:MIRN34 microRNA, human; D035683:MicroRNAs; D016376:Oligonucleotides, Antisense