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

Abstract

BACKGROUND: 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. OBJECTIVES: 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 a in MDA-MB 231 breast cancer cell line. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.