Modulation of transforming growth factor beta1 gene expression in the mammary gland by insulin-like growth factor I and octreotide.

  • Authors:
    • H Huynh
    • W Beamer
    • M Pollak
    • T W Chan
  • View Affiliations

  • Published online on: February 1, 2000     https://doi.org/10.3892/ijo.16.2.277
  • Pages: 277-358
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Abstract

Transforming growth factor beta1 (TGF-beta1) has been shown to exhibit anti-proliferative activity for mammary gland epithelial cells and for human breast cancer cells. Insulin-like growth factor I (IGF-I), in contrast, is a well-characterized mitogenic and anti-apoptotic factor involved in mammary gland physiology. In order to examine the hypothesis that IGF-I suppresses TGF-beta1 expression in the mammary gland, we studied the effect of various manipulations of the growth hormone - IGF-I axis on TGF-beta1 mRNA abundance. Administration of IGF-I to intact animal suppressed TGF-beta1 mRNA levels in a dose-dependent manner to approximately 20% of control levels. Administration of the somatostatin analogue octreotide in a manner previously shown to acutely suppress the growth hormone - IGF-I axis increased mammary gland TGF-beta1 expression approximately 3-fold. Transgenic mice overexpressing growth hormone expressed TGF-beta1 in the mammary gland at only approximately 12% of the level of control animals, while mice IGF-I deficient due to the mutation expressed TGF-beta1 at slightly higher levels than control animals. The large differences in TGF-beta1 expression between control and GH-transgenic animals were correlated with major differences in architecture of the mammary gland, while the appearance of mammary glands of normal and animals was similar. These data document a previously unrecognized relationship between TGF-beta1 and IGF-I physiology in the mammary gland, and suggest a novel mechanism by which somatostatin analogues influence the proliferative behaviour of breast epithelial cells.

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February 2000
Volume 16 Issue 2

Print ISSN: 1019-6439
Online ISSN:1791-2423

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APA
Huynh, H., Beamer, W., Pollak, M., & Chan, T. (2000). Modulation of transforming growth factor beta1 gene expression in the mammary gland by insulin-like growth factor I and octreotide.. International Journal of Oncology, 16, 277-358. https://doi.org/10.3892/ijo.16.2.277
MLA
Huynh, H., Beamer, W., Pollak, M., Chan, T."Modulation of transforming growth factor beta1 gene expression in the mammary gland by insulin-like growth factor I and octreotide.". International Journal of Oncology 16.2 (2000): 277-358.
Chicago
Huynh, H., Beamer, W., Pollak, M., Chan, T."Modulation of transforming growth factor beta1 gene expression in the mammary gland by insulin-like growth factor I and octreotide.". International Journal of Oncology 16, no. 2 (2000): 277-358. https://doi.org/10.3892/ijo.16.2.277