title: Pattern of IGF-1 variants' expression in human cancer cell lines using a novel q-RT-PCR approach.
abstract: OBJECTIVE
  Although insulin-like growth factor-1 (IGF-1) is well-implicated in cancer biology, the potential roles of IGF-1 variants in different types of cancer are largely unknown. The aim of the present study was to in vitro characterize several human cancers for their IGF-1 variant expression patterns.
  
  
  METHODS
  Using a novel quantitative real-time polymerase chain reaction (qRT-PCR) assay, twelve human cancer cell lines were investigated for their endogenous expression levels of IGF-1 variants, including classes. Additionally, the hormonal regulation of IGF-1 transcripts was investigated in PC3 cells.
  
  
  RESULTS
  IGF-1Ea and Eb were found at higher levels in KLE and MEL28 cells, respectively. MCF7 had the lowest expression of Ec peptide and, along with MB231, lacked IGF-1Eb. In most cases, class 1 proved as the predominant origin. Estradiol (E2) or dexamethasone (Dexa) significantly modulated IGF-1Ea and IGF-1Eb and down-regulated the Ec peptide in PC3.
  
  
  CONCLUSIONS
  Our results contribute to the notion of distinct roles of IGF-1 isoforms in human cancer depending on the type of malignancy.
authors.affiliation: Department of Experimental Physiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece panutsoschr@hotmail.com.
authors.forename: Panagiotis F
authors.initials: PF
authors.lastname: Christopoulos
authors.affiliation: Department of Experimental Physiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Anastassios
authors.initials: A
authors.lastname: Philippou
authors.affiliation: Department of Experimental Physiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Michael
authors.initials: M
authors.lastname: Koutsilieris
mesh_terms: D003907:Dexamethasone / Q000494:pharmacology; D004958:Estradiol / Q000502:physiology; D015870:Gene Expression; D019382:Human Growth Hormone / Q000502:physiology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D061986:MCF-7 Cells; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C583557:IGF1 protein, human; D020033:Protein Isoforms; D019382:Human Growth Hormone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone
keywords: Ec peptide; IGF-1 classes; IGF-1 isoforms; IGF-1Ea; IGF-1Eb; cancer cell lines