Dicer-mediated upregulation of BCRP confers tamoxifen resistance in human breast cancer cells.

ABSTRACT:

Purpose

Tamoxifen (Tam) is the most prescribed hormonal agent for treatment of estrogen receptor α (ERα)-positive breast cancer patients. Using microarray analysis, we observed that metastatic breast tumors resistant to Tam therapy had elevated levels of Dicer.

Experimental design

We overexpressed Dicer in ERα-positive MCF-7 human breast cancer cells and observed a concomitant increase in expression of the breast cancer resistance protein (BCRP). We thus hypothesized that Tam resistance associated with Dicer overexpression in ERα-positive breast cancer cells may involve BCRP. We analyzed BCRP function in Dicer-overexpressing cells using growth in soft agar and mammosphere formation and evaluated intracellular Tam efflux.

Results

In the presence of Tam, Dicer-overexpre

SUBMITTER: Selever J 

PROVIDER: S-EPMC3281508 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature