Transcription profiling of human MCF-7 breast cancer cell line transfected with adenovirus expressing Erbeta treated with estrogen or tamoxifen reveals tamoxifen can selectively regulate a unique set of >60 genes, which are minimally regulated by estradiol (E2) or raloxifene.

ABSTRACT: The beneficial effect of the selective estrogen receptor (ER) modulator tamoxifen in the treatment and prevention of breast cancer is assumed to be through its ability to antagonize the stimulatory actions of estrogen, although tamoxifen can also have some estrogen-like agonist effects. Here, we report that, in addition to these mixed agonist/antagonist actions, tamoxifen can also selectively regulate a unique set of >60 genes, which are minimally regulated by estradiol (E2) or raloxifene in ERalpha-positive MCF-7 human breast cancer cells. This gene regulation by tamoxifen is mediated by ERalpha and reversed by E2 or ICI 182,780. Introduction of ERbeta into MCF-7 cells reverses tamoxifen action on approximately 75% of these genes. To examine whether these genes might serve as markers of t

ORGANISM(S): Homo sapiens

SUBMITTER: Edmund Chang 

PROVIDER: E-GEOD-4025 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress