Tyrosine phosphorylation of an erbB-2 related p90 protein induced by estrogen in human breast epithelial cells.
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- Published online on: May 1, 2000 https://doi.org/10.3892/ijo.16.5.1035
- Pages: 1035-1077
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Abstract
Estrogen induced erbB-2 tyrosine kinase activity in human breast epithelial cells irrespective of estrogen receptor expression. MCF10A is an immortal normal human breast epithelial cell line which does not express estrogen receptor. After treatment of MCF10A cells with estradiol-17beta (E2), a phosphorylated 90 kDa protein which co-immunoprecipitates with p185erbB-2 is detected. The response is transient, detected after 1-5 min exposure to E2, and dose dependent, occurring at 10-10 M E2. A similar response was observed for MCF10A cells transfected with an estrogen receptor, estrogen receptor expressing MCF-7 cells, and estrogen receptor-negative MDA-MB-435 cells but at 10-11 M E2. Overexpression of c-erbB-2 in MCF10A cells prolonged the phosphorylated p90 response to E2.
