The effect of steroid hormones and selected endocrine disruptive chemicals on the expression of endogenous retrovirus sequences in the human breast cancer cell line MCF-7

Abstract

The endogenous retrovirus research group at Genøk – Centre for Biosafety is studying the effect of endocrine disruptive chemicals on the expression of endogenous retrovirus sequences in a number of cell lines.

About 25-40 million years ago, our ancestors were infected by a retrovirus which was endogenised through evolution. This human endogenous retrovirus, HERV-W, which encodes for an envelope protein, syncytin-1, has adapted a physiological role by being involved in placentogenesis. Previous studies have suggested that this envelope gene is under steroid hormone regulation.

As endocrine disruptive chemicals (EDCs) have been implicated in a range of pathologies observed in wildlife and humans, work has been carried out to identify if such EDCs may have an effect on the expression of endogenous retrovirus sequences within the human genome.

The work in this thesis has focused on treatment of the breast cancer cell line MCF-7 with the steroid hormones oestradiol and progesterone and the chemicals Bisphenol A and Roundup®. A cytotoxicity assay was carried out to observe cell viability following hormone or chemical treatment.

This study shows a constitutive expression of syncytin-1 in the cell line MCF-7 and the effect of hormones and chemicals on cell viability following treatment. Limitations in the experimental set up have been identified and further optimisation strategies have been discussed.