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Estradiol Increases IRS-1 Gene Expression and Insulin Signaling in Breast Cancer Cells

https://doi.org/10.1006/bbrc.2001.5815Get rights and content

Abstract

This study demonstrates how the potentiating effects of E2 on insulin signaling in endoplasmic reticulum-positive breast cancer cells are consequent to an enhanced IRS-1 expression. It induces an increase of both PI-3K/AKT and ERK1/2 activities. A direct action of E2 in the regulating mouse IRS-1 gene is also investigated in both Chinese hamster ovary and MCF-7 cells that are transfected with mouse IRS-1 regulatory sequences. The authors have reported, for the first time, how E2 induction of IRS-1 mRNA was correlated with a direct positive regulatory role of E2 on the IRS-1 promoter. This effect seems to be not strictly related to the cell type.

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1

L.M. and M.S. contributed equally to this study.

2

To whom correspondence and reprint requests should be addressed at Dipartimento di Biologia Cellulare, Università degli Studi della Calabria, 87030 Arcavacata-Rende Cosenza, Italy. Fax: (39) (0984) 492911. E-mail: [email protected].

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