
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Regular Articles |
Laboratory of Molecular Endocrinology, Division of Cellular and Molecular Research, National Cancer Centre of Singapore, Singapore 169610 [T. W. C., H. H.], and Lady Davis Institute for Medical Research, Department of Medicine, McGill University, Montreal, Quebec H3T 1E2, Canada [M. P.]
The antiestrogens ICI 182,780 (ICI) and tamoxifen are clinically useful in the treatment of estrogen receptor-positive breast tumors. We assessed the in vivo effects of ICI, tamoxifen, and estradiol on the insulin-like growth factor (IGF) signaling pathway in the rat mammary gland. ICI significantly decreased the size of the lobular structures, Ki-67 labeling index, and insulin-like growth factor binding protein (IGFBP)-2 and IGFBP-5 gene expression. Treatment of rats with 1, 1.5, and 2 mg of ICI/kg body weight/week resulted in a 2-, 7-, and 8-fold increase in IGFBP-3 transcripts. High doses of ICI increased mammary IGF-1 gene expression by 2-fold (P < 0.01) but decreased IGF-1R and its autophosphorylation to
30% of the control mammary gland. IRS-1, IRS-2, and c-Raf-1 levels in the ICI-treated mammary glands were approximately 30, 15, and 40% of controls, respectively. Basal phosphorylation of IRS-1, Akt-1, and the p85 subunit of phosphatidylinositol 3-kinase (PI-3K) were low but detectable after ICI treatment. Despite a significant reduction in levels of IGF-1R, IRS-1, and IRS-2 phosphorylation, phospho p42/p44 MAPK levels were only slightly decreased. Tamoxifen-induced growth inhibition was associated with slight stimulation of IGFBP-3 gene expression and reduction in IRS-2 levels. Basal phosphorylation of IGF-1R, IRS-1, and p85 subunit of PI-3K was decreased by tamoxifen. Estradiol-induced epithelial cell proliferation was associated with inhibition of IGFBP-3 gene expression, stimulation of IGFBP-2 gene expression, and increases in IGF-1R, IRS-1, IRS-2, and c-Raf-1 levels. Although basal phosphorylation of IGF-1R, IRS-1, IRS-2, Akt-1, and the p85 subunit of PI-3K was significantly increased by estradiol, basal phospho p44/42 MAPK was significantly reduced. The data indicate that in addition to their classic actions, antiestrogens have major effects on IGF signaling pathways.
This article has been cited by other articles:
![]() |
J. D. Veldhuis, D. M. Keenan, and C. Y. Bowers Peripheral estrogen receptor-{alpha} selectively modulates the waveform of GH secretory bursts in healthy women Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2007; 293(4): R1514 - R1521. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Sisci, C. Morelli, C. Garofalo, F. Romeo, L. Morabito, F. Casaburi, E. Middea, S. Cascio, E. Brunelli, S. Ando, et al. Expression of nuclear insulin receptor substrate 1 in breast cancer J. Clin. Pathol., June 1, 2007; 60(6): 633 - 641. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Martin and R. C. Baxter Expression of Insulin-Like Growth Factor Binding Protein-2 by MCF-7 Breast Cancer Cells Is Regulated through the Phosphatidylinositol 3-Kinase/AKT/Mammalian Target of Rapamycin Pathway Endocrinology, May 1, 2007; 148(5): 2532 - 2541. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Yu, Y. Hao, and L. A. Feig The R-Ras GTPase Mediates Cross Talk between Estrogen and Insulin Signaling in Breast Cancer Cells. Mol. Cell. Biol., September 1, 2006; 26(17): 6372 - 6380. [Abstract] [Full Text] [PDF] |
||||
![]() |
L-A Martin, S Pancholi, C M W Chan, I Farmer, C Kimberley, M Dowsett, and S R D Johnston The anti-oestrogen ICI 182,780, but not tamoxifen, inhibits the growth of MCF-7 breast cancer cells refractory to long-term oestrogen deprivation through down-regulation of oestrogen receptor and IGF signalling Endocr. Relat. Cancer, December 1, 2005; 12(4): 1017 - 1036. [Abstract] [Full Text] [PDF] |
||||
![]() |
D Montanaro, M Maggiolini, A G Recchia, R Sirianni, S Aquila, L Barzon, F Fallo, S Ando, and V Pezzi Antiestrogens upregulate estrogen receptor {beta} expression and inhibit adrenocortical H295R cell proliferation J. Mol. Endocrinol., October 1, 2005; 35(2): 245 - 256. [Abstract] [Full Text] [PDF] |
||||
![]() |
L.-A. Martin, I. Farmer, S. R D Johnston, S. Ali, and M. Dowsett Elevated ERK1/ERK2/estrogen receptor cross-talk enhances estrogen-mediated signaling during long-term estrogen deprivation Endocr. Relat. Cancer, July 1, 2005; 12(Supplement_1): S75 - S84. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Eng-Wong, S. D. Hursting, D. Venzon, S. N. Perkins, and J. A. Zujewski Effect of Raloxifene on Insulin-Like Growth Factor-I, Insulin-Like Growth Factor Binding Protein-3, and Leptin in Premenopausal Women at High Risk for Developing Breast Cancer Cancer Epidemiol. Biomarkers Prev., December 1, 2003; 12(12): 1468 - 1473. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. J. Butt, K. A. Dickson, F. McDougall, and R. C. Baxter Insulin-like Growth Factor-binding Protein-5 Inhibits the Growth of Human Breast Cancer Cells in Vitro and in Vivo J. Biol. Chem., August 8, 2003; 278(32): 29676 - 29685. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. R. Levin Bidirectional Signaling between the Estrogen Receptor and the Epidermal Growth Factor Receptor Mol. Endocrinol., March 1, 2003; 17(3): 309 - 317. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. V. Lee, R. Schiff, X. Cui, D. Sachdev, D. Yee, A. P. Gilmore, C. H. Streuli, S. Oesterreich, and D. L. Hadsell New Mechanisms of Signal Transduction Inhibitor Action: Receptor Tyrosine Kinase Down-Regulation and Blockade of Signal Transactivation Clin. Cancer Res., January 1, 2003; 9(1): 516S - 523S. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Albanell and J. Baselga Unraveling Resistance to Trastuzumab (Herceptin): Insulin-Like Growth Factor-I Receptor, a New Suspect J Natl Cancer Inst, December 19, 2001; 93(24): 1830 - 1832. [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Meeting Abstracts Online |