title: MiR-23a-mediated migration/invasion is rescued by its target, IRS-1, in non-small cell lung cancer cells.
abstract: OBJECTIVE
  To determine the interaction between insulin receptor substrate-1 (IRS-1) and miR-23a on the migration and invasion of non-small cell lung cancer (NSCLC) cells, and to examine IRS-1 expression in NSCLC tissues and its correlation with clinicopathologic characteristics.
  
  
  METHODS
  The migration and invasion of A549 cells were measured using transwell assay. miR-23a levels were examined by quantitative reverse transcription-PCR and IRS-1 expression by Western blotting. The interaction between miR-23a and IRS-1 was examined by luciferase reporter assay. IRS-1 expression in 105 NSCLC specimens was determined by immunohistochemistry and its correlation with patient clinicopathologic characteristics was evaluated.
  
  
  RESULTS
  Transwell assay revealed that miR-23a significantly promoted the migration and invasion of A549 cells with a 44.0 and 44.6 % increase in the number of migrated and invading cells, respectively. Luciferase assay showed that miR-23a markedly reduced luciferase activities of A549 cells co-transfected with plasmids overexpressing the 3' UTR of IRS-1 mRNA (P < 0.05). Co-transfection of A549 cells with miR-23a and plasmids overexpressing IRS-1 significantly reduced the increase in the number of migrated and invading cells mediated by miR-23a. Immunohistochemistry showed low IRS-1 expression in 26.7 % and high IRS-1 expression in 73.3 % of the NSCLC specimens. Kaplan-Meier analysis revealed that the overall survival and disease-free survival of NSCLC were markedly longer in patients with high IRS-1 expression than those with low IRS-1 expression (P = 0.002). Multivariate Cox regression analysis showed that IRS-1 was an independent prognostic factor for the overall survival of NSCLC patients (RR 0.413 CI 0.238-0.718, P = 0.002).
  
  
  CONCLUSIONS
  There is an interaction between miR-23a and IRS-1 in the modulation of the migration and invasion of NSCLC cells. IRS-1 is variably expressed in NSCLC patients and correlates with NSCLC patient survival.
authors.affiliation: The Forth Department of Medicine Oncology, Harbin Medical University Cancer Hospital, Haping Road 150, Harbin, 150040, China.
authors.forename: Mengru
authors.initials: M
authors.lastname: Cao
authors.forename: Yulian
authors.initials: Y
authors.lastname: Li
authors.forename: Hailing
authors.initials: H
authors.lastname: Lu
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Meng
authors.forename: Long
authors.initials: L
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Cai
authors.forename: Xiaoqun
authors.initials: X
authors.lastname: Dong
mesh_terms: D020413:3' Untranslated Regions; D000595:Amino Acid Sequence; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000401:mortality* / Q000473:pathology*; D002465:Cell Movement; D049109:Cell Proliferation; D002681:China; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics / Q000378:metabolism*; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000401:mortality* / Q000473:pathology*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D020413:3' Untranslated Regions; C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; C552430:MIRN23a microRNA, human; D035683:MicroRNAs