title: Cigarette smoke condensate promotes pro-tumourigenic stromal-epithelial interactions by suppressing miR-145.
abstract: BACKGROUND
  Exposure to factors released from tobacco during chewing or smoking is recognized as a major risk factor for oral carcinogenesis and influences the phenotype of oral epithelial cells and fibroblasts within the underlying stroma. Micro(mi)RNA can regulate the expression of genes within cells, and previous studies show that tobacco products can alter the miRNA profiles in lung epithelial cells. However, the molecular alterations occurring in oral fibroblasts exposed to tobacco constituents remain to be elucidated.
  
  
  METHODS
  Oral fibroblasts were exposed to cigarette smoke condensate (CSC) and miRNA expression compared to untreated controls using tiling low-density arrays (TLDA). Expression of miRNA-145 was confirmed by quantitative (q)RT-PCR. The effect of CSC on fibroblast cell viability, motility and matrix metalloproteinase (MMP)-2 expression was measured using MTS, a wound scratch assay and qRT-PCR, respectively. Oral cancer cell migration in response to culture supernatants from mock, control or pre-miR-145-transfected CSC-treated fibroblasts was analysed by chemotaxis assay.
  
  
  RESULTS
  TLDA analysis identified widespread changes in the miRNA expression profile of fibroblasts exposed to CSC. Pri-, pre- and mature miRNA-145 were significantly down-regulated in response to CSC, and this was accompanied by up-regulated expression of MMP-2 and increased migration of fibroblasts compared to untreated controls. Re-expression of miR-145 abrogated the ability of fibroblasts to promote oral cancer cell chemotaxis in response to CSC.
  
  
  CONCLUSIONS
  These findings suggest that tobacco constituents influence the expression of miRNA within oral fibroblasts promoting a phenotype that increases oral cancer migration and sheds new light on the mechanisms underlying oral cancer pathogenesis.
authors.affiliation: Integrated Biosciences, School of Clinical Dentistry, University of Sheffield, Sheffield S10 2TA, UK.
authors.forename: A
authors.initials: A
authors.lastname: Pal
authors.forename: G
authors.initials: G
authors.lastname: Melling
authors.forename: E E
authors.initials: EE
authors.lastname: Hinsley
authors.forename: T D
authors.initials: TD
authors.lastname: Kabir
authors.forename: H E
authors.initials: HE
authors.lastname: Colley
authors.forename: C
authors.initials: C
authors.lastname: Murdoch
authors.forename: D W
authors.initials: DW
authors.lastname: Lambert
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology; D018929:Cell Culture Techniques; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced* / Q000473:pathology; D002633:Chemotaxis / Q000187:drug effects; D017077:Culture Media, Conditioned; D004847:Epithelial Cells / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects*; D020869:Gene Expression Profiling; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000187:drug effects; D035683:MicroRNAs / Q000032:analysis*; D046228:Microarray Analysis; D009061:Mouth Mucosa / Q000166:cytology / Q000187:drug effects*; D010641:Phenotype; D012342:RNA, Small Nuclear; D060888:Real-Time Polymerase Chain Reaction; D012906:Smoke / Q000009:adverse effects*; D017154:Stromal Cells / Q000187:drug effects; D062789:Tobacco Products / Q000009:adverse effects*; D014162:Transfection
chemical_list: D017077:Culture Media, Conditioned; C541010:MIRN145 microRNA, human; D035683:MicroRNAs; D012342:RNA, Small Nuclear; D012906:Smoke; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2