Overexpression of ovine insulin-like growth factor-I stimulates autonomous autocrine or paracrine growth in bovine mammary-derived epithelial cells

Donato Romagnolo, R. Michael Akers, Eric A. Wong, Pat L. Boyle, Thomas B. McFadden, Jeffrey D. Turner

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

To test the hypothesis that insulin-like growth factor-I (IGF-I) affects the growth of bovine mammary epithelial cells through an autocrine and/or paracrine pathway, a cell line (MD-IGF-I) was originated from MAC-T cells by cotransfection with a construct containing the cDNA for an ovine exon 2-encoded prepro-IGF-I under control of the mouse mammary tumor virus-long terminal repeat promoter. Clone MD-IGF-I contained multiple copies of the plasmid integrated into the genome, expressed the highest level of IGF-I mRNA, and secreted radioimmunoactive IGF-I into the medium. The mitogenic activity of MD-IGF-I cells was stimulated 80% by dexamethasone (DEX). The total DNA in MD-IGF-I cells was 2.5-fold higher than that in parental MAC-T cells in the presence of DEX. Conditioned medium from MD-IGF-I cells, induced with DEX, stimulated [3H]thymidine incorporation into DNA of MAC-T cells and uninduced MD-IGF-I cells. These data provide evidence that IGF-I was secreted into medium by MD-IGF-I cells. It is suggested that IGF-I can stimulate the growth of mammary epithelial cells by an autocrine and/or paracrine mode of action. The MD-IGF-I cell line may be a suitable system to study translational and posttranslational modifications of IGF-I peptides.

Original languageEnglish (US)
Pages (from-to)1774-1780
Number of pages7
JournalMolecular Endocrinology
Volume6
Issue number11
DOIs
StatePublished - Nov 1 1992
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Endocrinology

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