title: EGFR-blockade with erlotinib reduces EGF and TGF-β2 expression and the actin-cytoskeleton which influences different aspects of cellular migration in lens epithelial cells.
abstract: BACKGROUND
  After cataract surgery, residual lens epithelial cells migrate and proliferate within the capsular bag resulting in posterior capsule opacification (PCO). The up-regulation of TGF-β2, EGF and FGF-2 has been identified as a key factor in PCO pathogenesis leading to actin fiber assembly and alterations in the migration pattern. In this in vitro study, the influence of Erlotinib as a selective EGFR inhibitor is investigated on the cellular features indicated, which might promote a future clinical application.
  
  
  METHODS
  Expression of EGF, FGF-2 and TGF-β2 was measured using RT-PCR and ELISA in human lens epithelial cells (HLEC). Computational data of an in vitro time lapse microscopy assay were used for statistical analysis of single cell migration with a particular focus on cell-cell interaction; cell velocity distribution; and displacement before, during and after mitosis. The effect of Erlotinib on the actin-cytoskeleton was evaluated using Alexa Fluor 488 Phalloidin and epifluorescence microscopy.
  
  
  RESULTS
  EGF and TGF-β2 mRNA expression and protein levels are reduced by Erlotinib, while FGF-2 expression remained stable. Overall fluidity of cell-cell interaction is less in the presence of Erlotinib compared to the control and the velocity distribution across all cells becomes less uniform within the cell cluster. After mitosis, HLEC move significantly faster without EGFR inhibition, which can be completely blocked by Erlotinib. Furthermore, Erlotinib diminishes the amount of actin stress fibers and the stress fiber diameter.
  
  
  CONCLUSIONS
  As a novel effect of Erlotinib on HLEC, we describe the down-regulation of EGF and TGF-β2 expression, both are crucial factors for PCO development. Cellular movement displays complex alterations under EGFR inhibition, which is partly explained by actin fiber depletion. These findings further underline the role of Erlotinib in pharmacologic PCO prophylaxis.
authors.affiliation: Cell- and Molecular Biology Laboratory, Department of Ophthalmology, Ludwig-Maximilians-University , Munich , Germany and.
authors.forename: C
authors.initials: C
authors.lastname: Wertheimer
authors.forename: R
authors.initials: R
authors.lastname: Liegl
authors.forename: M
authors.initials: M
authors.lastname: Kernt
authors.forename: D
authors.initials: D
authors.lastname: Docheva
authors.forename: A
authors.initials: A
authors.lastname: Kampik
authors.forename: K H
authors.initials: KH
authors.lastname: Eibl-Lindner
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D000069347:Erlotinib Hydrochloride; D006801:Humans; D007908:Lens, Crystalline / Q000166:cytology; D008856:Microscopy, Fluorescence; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D059008:Time-Lapse Imaging; D053781:Transforming Growth Factor beta2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D012333:RNA, Messenger; D053781:Transforming Growth Factor beta2; D004815:Epidermal Growth Factor; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors
keywords: Actin cytoskeleton; EGF-receptor (EGFR); cell migration; erlotinib; growth factors; pharmacologic prophylaxis; posterior capsule opacification