Transcriptional effects of metal ions on the bovine oxytocin and the thymidine kinase-ERE promoter through the estrogen receptor α in MDA-MB 231 breast cancer cell line

Some of metal ions as environmental pollutants show estrogenic activity. This xenostrogenic compounds can be caused carcinogenicity in organs. The mechanism of carcinogenicity of metal ions is not clarified. In this study, we investigated the Transcriptional effects of variety of metal ions on the bovine oxytocin and the thymidine kinase-ERE promoter by estrogen receptor αin MDA-MB 231 breast cancer cell line. Cells were plated into flask (75cm2) at 1.3 density or into 12- well plates (Nunc) at a density of 100000 cells per well and were transfected with a total of 3 μg of plasmid DNA using calcium phosphate coprecipitation. Oestrogen and some metal ions were used for stimulation of transfected cells. Our results showed that copper and cadmium ions activating specifically the oxytocin promoter, and cobalt and possibly, mercury ions activating specifically the ERE-controlled promoter and the majority of the ions did not affect transcriptional activation significantly. The study revealed that some metal ions show estrogenic activity by classical or non-classical mechanisms as well as some metal ions exhibit estrogenic activity by undetermined mechanisms in transfected MDA-MB 231 cell line.