title: Molecular events associated with ciclosporin A-induced gingival overgrowth are attenuated by Smad7 overexpression in fibroblasts.
abstract: OBJECTIVE
  Ciclosporin A (CsA)-induced gingival overgrowth is attributed to an exaggerated accumulation of extracellular matrix, which is mainly due to an increased expression of transforming growth factor-β1 (TGF-β1). Herein, the in vitro investigation of effects of overexpression of Smad7, a TGF-β1 signaling inhibitor, in the events associated with CsA-induced extracellular matrix accumulation was performed.
  
  
  METHODS
  The effects of Smad7 were assessed by stable overexpression of Smad7 in fibroblasts from normal gingiva. Smad7-overexpressing cells and control cells were incubated with CsA, and synthesis of type I collagen, production and activity of MMP-2 and cellular proliferation were evaluated by ELISA, zymography, growth curve, bromodeoxyuridine incorporation assay and cell cycle analysis. The effects of CsA on cell viability and apoptosis of fibroblasts from normal gingiva were also evaluated. Western blot and immunofluorescence for phospho-Smad2 were performed to measure the activation of TGF-β1 signaling.
  
  
  RESULTS
  Although the treatment with CsA stimulated TGF-β1 production in both control and Smad7-overexpressing fibroblasts, its signaling was markedly inhibited in Smad7-overexpressing cells, as revealed by low levels of phospho-Smad2. In Smad7-overexpressing cells, the effects of CsA on proliferation, synthesis of type I collagen and the production and activity of MMP-2 were significantly blocked. Smad7 overexpression blocked CsA-induced fibroblast proliferation via p27 regulation. Neither CsA nor Smad7 overexpression induced cell death.
  
  
  CONCLUSIONS
  The data presented here confirm that TGF-β1 expression is related to the molecular events associated with CsA-induced gingival overgrowth and suggest that Smad7 overexpression is effective in blocking these events, including proliferation, type I collagen synthesis and MMP-2 activity.
authors: Department of Oral Diagnosis, School of Dentistry, State University of Campinas, Piracicaba, São Paulo, Brazil.
authors: L M
authors: LM
authors: Sobral
authors: F
authors: F
authors: Aseredo
authors: M
authors: M
authors: Agostini
authors: A
authors: A
authors: Bufalino
authors: M C C
authors: MC
authors: Pereira
authors: E
authors: E
authors: Graner
authors: R D
authors: RD
authors: Coletta
mesh_terms: D000963:Antimetabolites; D017209:Apoptosis / Q000187:drug effects; D001973:Bromodeoxyuridine; D018929:Cell Culture Techniques; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D024042:Collagen Type I / Q000187:drug effects; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D016572:Cyclosporine / Q000009:adverse effects* / Q000037:antagonists & inhibitors; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D005881:Gingiva / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019214:Gingival Overgrowth / Q000139:chemically induced*; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000187:drug effects; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051899:Smad2 Protein / Q000187:drug effects; D051906:Smad7 Protein / Q000235:genetics / Q000494:pharmacology*; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000037:antagonists & inhibitors; D055815:Young Adult
chemical_list: D000963:Antimetabolites; D024042:Collagen Type I; D047428:Protein Kinase Inhibitors; C497782:SMAD2 protein, human; C497806:SMAD7 protein, human; D051899:Smad2 Protein; D051906:Smad7 Protein; D053773:Transforming Growth Factor beta1; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016572:Cyclosporine; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; D001973:Bromodeoxyuridine