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Hormonal Control of Growth Factor Receptor Expression a
Author(s) -
BORTOLI MICHELE DE,
MAGGIORA PIERA,
CAPELLO DANIELA,
ANTONIOTTI SUSANNA,
SAVIOZZI SILVIA,
SAPEI MARIA LUISA,
DATI CLAUDIO
Publication year - 1996
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1996.tb16248.x
Subject(s) - autocrine signalling , erbb , antiestrogen , paracrine signalling , cancer research , biology , tamoxifen , estrogen receptor , receptor tyrosine kinase , neuregulin 1 , tyrosine kinase , receptor , signal transduction , microbiology and biotechnology , cancer , breast cancer , genetics
In this report, we have discussed a series of results obtained in our laboratory that, together with data by other authors, demonstrate that the expression of the erbB-2 tyrosine kinase receptor oncogene in breast cancer cells is regulated by multiple factors and hormones, which modulate their growth and differentiation. In particular, we have shown that estrogens specifically inhibit erbB-2 expression by transcriptional repression, which is exerted through a sequence within the erbB-2 gene promoter. Estrogens control mammary cell growth directly, by inducing early gene expression, and indirectly, by increasing autocrine growth factor production or decreasing growth inhibitors. The data presented here suggest that mammary cells respond to estrogen also by modifying the receptor array on their surface, thus setting their own sensitivity to the different autocrine and paracrine factors. As a first consequence, the modulation of erbB-2 expression level by antiestrogen may represent a point to consider when selecting breast cancer patients for hormonal therapy, in those (few) cases where estrogen receptor positivity accompanies erbB-2 amplification. On the other hand, antiestrogen-induced upregulation of erbB-2 may improve tumor targeting of drugs designed to interact or interfere with erbB-2, such as humanized antibodies, immunotoxins, or engineered ligands. These possibilities should be tested in appropriate model systems in the future.