Pattern of IGF-1 variants' expression in human cancer cell lines using a novel q-RT-PCR approach.

BACKGROUND/AIM 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. MATERIALS AND 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. CONCLUSION Our results contribute to the notion of distinct roles of IGF-1 isoforms in human cancer depending on the type of malignancy.