title: Effect of doxycycline on proliferation, MMP production, and adhesion in LAM-related cells.
abstract: Matrix metalloproteinases (MMPs) have been implicated in lung cyst formation in lymphangioleiomyomatosis (LAM). As doxycycline inhibits MMP activity in vivo, some patients take doxycycline, as one report has suggested a possible benefit in LAM. However, there have been no randomized controlled clinical trials of doxycycline for LAM, and any mechanism of action is unclear. Here, we examine previously proposed mechanisms of actions. Cell proliferation and adhesion were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction and Cytomatrix cell adhesion kits. Apoptosis was examined by TdT-mediated dUTP nick end labeling (TUNEL) assay. MMP-2 expression was examined by quantitative real-time PCR and zymography in doxycycline-treated ELT3 cells and tumor growth using angiomyolipoma-derived tumor xenografts in nude mice. In ELT3 cells, >or=25 microg/ml doxycycline decreased proliferation, increased apoptosis, and caused a change in cell morphology associated with redistribution of actin stress filaments. Reduction in proliferation was also seen in human angiomyolipoma-derived cells. Cell adhesion to ECM proteins was decreased by doxycycline at 50 microg/ml and prevented detachment of already adherent cells. There was no effect of doxycycline on MMP-2 expression or activity in vitro. In the xenograft model, doxycycline (30 mg*kg(-1)*day(-1)) had no effect on tumor growth, final tumor weight, or tumor lysate MMP levels. Doxycycline at doses >or= 25 microg/ml inhibited cell proliferation and adhesion, possibly by a toxic effect. Doxycycline had no effect on MMP-2 expression or activity or tumor growth in the xenograft model. Any possible in vivo effect is unlikely to be mediated by MMP-2 or reduced cell proliferation.
authors.affiliation: Division of Therapeutics and Molecular Medicine and Respiratory Biomedical Research Unit, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH United Kingdom. william.chang@nottingham.ac.uk
authors.forename: William Y C
authors.initials: WY
authors.lastname: Chang
authors.forename: Debbie
authors.initials: D
authors.lastname: Clements
authors.forename: Simon R
authors.initials: SR
authors.lastname: Johnson
mesh_terms: D018207:Angiomyolipoma / Q000378:metabolism / Q000473:pathology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004318:Doxycycline / Q000008:administration & dosage*; D006801:Humans; D066298:In Vitro Techniques; D018192:Lymphangioleiomyomatosis / Q000473:pathology* / Q000503:physiopathology*; D020778:Matrix Metalloproteinase 2 / Q000187:drug effects / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000096:biosynthesis*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011480:Protease Inhibitors / Q000008:administration & dosage*; D051381:Rats; D014183:Transplantation, Heterologous
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D011480:Protease Inhibitors; D020782:Matrix Metalloproteinases; D020778:Matrix Metalloproteinase 2; D004318:Doxycycline