Inhibitory effect of hydroxyflutamide plus tamoxifen on oestradiol-induced growth of MCF-7 breast cancer cells

Androgen expression & clinicopathological features in male breast cancer

Aim: To investigate prognostic features in male breast cancer (MBC). Methods: Clinicopathological information from 40 MBC patients was retrospectively reviewed. Androgen receptor (AR) and estrogen receptor (ER) were prospectively stained out in 22 cases and counted through software program analysis. Results: Median age was 65.5 years; most cases were Stage II (40%), Grade II (37.5%), ER ≥10% (72.5%) and PgR ≥10% (75%). AR >10% was found in 17 of 22 cases. Although AR expression was correlated with ER, there are some cells without coexpression. Axillary node involvement was associated with DFS (p = 0.001) and age (p = 0.002) was associated with overall survival. Conclusion: ER is expressed in most MBC cases and is correlated with AR. Axillary involvement and age were associated with survival.

The Role of Androgen Receptor in Breast Cancer

The androgen receptor (AR) is a proven clinical target in prostate cancer. Recent research indicates that it is an emerging hormonal target in breast cancer as well, with potential clinical benefit in both estrogen receptor(ER) positive and negative tumors. Compared to the ER, AR contains unique functional domains with relevance to its altered role in human breast cancer. The majority of ER-positive tumors express AR, and a significant percentage of ER-negative tumors might benefit from combined targeting of AR and the ErbB2/HER2 oncogene. Signaling downstream of AR might also affect many clinically important pathways which are also emerging clinical targets in breast cancer. AR expression might also play a role during tumor progression to metastatic disease. The role of AR as a new important biomarker in breast cancer will be reviewed herein.

Reciprocal regulation of ZEB1 and AR in triple negative breast cancer cells

Zinc-finger enhancer binding protein (ZEB1) is a transcription factor involved in the progression of cancer primarily through promoting epithelial to mesenchymal transition (EMT). ZEB1 represses the expression of E-cadherin by binding to E-box sequences in the promoter, thus decreasing epithelial differentiation. We show that ZEB1 and androgen receptor (AR) cross-talk in triple negative breast cancer cell lines. Chromatin immunoprecipitation analysis demonstrates that ZEB1 binds directly to the E-box located in the AR promoter. ZEB1 suppression by stably transfecting shRNA in a triple negative breast cancer cell line resulted in a decrease of AR mRNA, protein, and AR downstream targets. ZEB1 knockdown in triple negative breast cancer cells sensitized the cells to bicalutamide by reducing migration compared to the control cells. Conversely, blockade of AR signaling with bicalutamide resulted in a suppression of ZEB1 protein expression in two triple negative breast cancer cell lines. Furthermore, using a breast cancer tissue microarray, a majority of triple negative breast cancers exhibit positive staining for both ZEB1 and AR. Taken together, these results indicate that ZEB1 and AR regulate each other to promote cell migration in triple negative breast cancer cells.

Synthesis and anticancer activity of N-bis(trifluoromethyl)alkyl-N'-thiazolyl and N-bis(trifluoromethyl)alkyl-N'-benzothiazolyl ureas

A number of N-bis(trifluoromethyl)alkyl-N'-thiazolyl and -benzothiazolyl ureas have been synthesized and evaluated for their in vitro antiproliferative activities against the human cancer cell lines at the National Cancer Institute (NCI, USA). The activity was shown for compounds 8a,c and 9a-c. The most sensitive cell lines relative to the tested compounds are: 8c PC-3 (prostate cancer, logGI(50) -7.10), 9c SNB-75 (CNS cancer, logGI(50) -5.84), 9b UO-31 (renal cancer, logGI(50) -5.66), and SR (leukemia, logGI(50) -5.44) human cancer cells.

Androgen stimulates mitogen-activated protein kinase in human breast cancer cells

The mechanisms by which androgens modulate breast cancer cell growth are largely unknown. Using cultured human PMC42 breast cancer cells, we have determined effects of the androgen R1881 on the activity of the mitogen-activated protein kinases extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 kinase. R1881 did not alter JNK and p38 kinase activity, but activated ERK in a dose-dependent manner. Activation was rapid, peaking at 5 min followed by a decline to baseline after 30-60 min, and was accompanied by tyrosine phosphorylation of ERK. The androgen antagonist flutamide elevated ERK to similar levels and DNA synthesis to levels half those seen with R1881; in addition, excess flutamide lowered R1881-stimulated DNA synthesis to levels seen with flutamide alone. These findings suggest (i) that in human PMC42 breast cancer cells R1881 activates ERK through a non-genomic mechanism, (ii) that this non-genomic mechanism is equivalently activated by the androgen antagonist flutamide, and (iii) that androgen/antiandrogen effect on DNA synthesis may involve both genomic and non-genomic mechanisms. These findings may have important implications for the clinical use of such agents in breast cancer.