title: Expression of the insulin-like growth factor 1 (IGF-1) and type I IGF receptor mRNAs in human HLE-B3 lens epithelial cells.
abstract: OBJECTIVE
  The E peptide of the IGF-1Ec transcript has been documented to stimulate the growth of different cell lines, via a type I IGF-1 receptor (IGF-1R)-independent mechanism. The aim of the present study was to determine the implication of the IGF-1Ec isoform into the posterior capsule opacification process in human lens epithelium.
  
  
  METHODS
  The expression of the IGF-1 system was characterized in human HLE-B3 lens epithelium cells and the mitogenic activity of IGF-1 and synthetic E peptide and the effects of growth hormone (GH) and dihydrotestosterone (DHT) were examined, using qualitative real-time PCR, RT-PCR, Western blot analysis and trypan blue exclusion assays in wild-type and IGF-1R knock-out HLE-B3 cells.
  
  
  RESULTS
  The data showed that HLE-B3 cells express only the IGF-1Ea and IGF-1R transcripts. GH increased the expression of IGF-1Ea and of the previously undetectable IGF-1Eb mRNA. Finally, IGF-1 did not present any activity in the knock-out cells.
  
  
  CONCLUSIONS
  The IGF-1Ea isoform is the main source for the formation of mature IGF-1 in HLE-B3 cells. The effects of exogenous IGF-1 depend on the existence of IGF-1R. IGF-1 Ec is not expressed even in the presence of GH or DHT nor has it any effect on cell proliferation.
authors.affiliation: Department of Ophalmology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Marilita M
authors.initials: MM
authors.lastname: Moschos
authors.forename: Athanasios
authors.initials: A
authors.lastname: Armakolas
authors.forename: Anastasios
authors.initials: A
authors.lastname: Philippou
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pissimissis
authors.forename: Zacharoula
authors.initials: Z
authors.lastname: Panteleakou
authors.forename: Adrianos
authors.initials: A
authors.lastname: Nezos
authors.forename: Maria
authors.initials: M
authors.lastname: Kaparelou
authors.forename: Michael
authors.initials: M
authors.lastname: Koutsilieris
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation; D013196:Dihydrotestosterone / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression; D013006:Growth Hormone / Q000494:pharmacology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D007908:Lens, Crystalline / Q000166:cytology / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D017526:Receptor, IGF Type 1 / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D020033:Protein Isoforms; D012333:RNA, Messenger; D013196:Dihydrotestosterone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D017526:Receptor, IGF Type 1