The cellular and molecular effects of the androgen receptor agonist, Cl-4AS-1, on breast cancer cells.

PURPOSE: The androgen receptor (AR) has attracted attention in the treatment of breast cancer. Due to the undesirable side effects of AR agonists, attempts have been undertaken to develop selective AR modulators. One of these compounds is Cl-4AS-1. This study examined this compound more closely at the cellular and molecular levels. METHODS: Three different breast cancer cell lines were utilized, namely the luminal MCF-7 cells, the molecular apocrine MDA-MB-453 cells, and the triple negative, basal MDA-MB-231 cells. RESULTS: High and significant concordance between dihydrotestosterone (DHT) and Cl-4AS-1 in regulation of gene expression in MDA-MB-453 cells was found. However, some differences were noted including the expression of AR, which was upregulated by DHT, but not Cl-4AS-1. In addition, both DHT and Cl-4AS-1 caused a similar morphological change and reorganization of the actin structure of MDA-MB-453 cells into a mesenchymal phenotype. Treatment of cells with DHT resulted in induction of proliferation of MCF-7 and MDA-MB-453 cells, but no effect was observed on the growth of MDA-MB-231 cells. On the other hand, increasing doses of Cl-4AS-1 resulted in a dose-dependent inhibition on the growth of the three cell lines. This inhibition was a result of induction of apoptosis whereby Cl-4AS-1 caused a block in entry of cells into the S-phase followed by DNA degradation. CONCLUSIONS: These results indicate that although Cl-4AS-1 has characteristics of classical AR agonist, it has dissimilar properties that may make it useful in treating breast cancer.

Differential expression and androgen regulation of microRNAs and metalloprotease 13 in breast cancer cells.

MicroRNA molecules (miRNAs) play important roles in regulating cell behavior. The expression of certain miRNAs has been shown to be regulated by the androgen receptor (AR), which seems to have a critical role in the tumorigenic process of breast cancer. The differential expression of 84 miRNAs was first examined in three breast cancer cell lines: the luminal MCF-7 and T47D cells and the molecular apocrine MDA-MB-453 cells. Analysis of basal expression of miRNAs revealed that each cell line had distinct miRNA expression where let-7a and -7b were markers of MDA-MB-453 cells, whereas miR-205 was a marker for the luminal cell lines. Treating the cells with the AR agonist, CI-4AS-1, resulted in unique alterations in the expression of specific miRNA among the three cell lines. Particularly, the expression of miR-100 and miR-125 was reduced in MDA-MB-453 cells by five and three folds, respectively. This effect was simultaneous with AR-induced increase in the expression and extracellular release of metalloprotease-13 (MMP13). Transfection of cells with either miR-100 or miR-125b negated the induction of MMP13 release. Additionally, AR activation induced a morphological alteration of MDA-MB-453 cells, which was blocked by miR-125b only. Collectively, these data indicate that AR may control the biological behavior of breast cancer cells and protein expression via miRNAs.