Cyclosporine A inhibition of prolactin-dependent up-regulation of BRCA1 protein expression in human breast cell lines.

Background: Previously, we reported experimental evidence that BRCA1, breast and ovarian cancer susceptibility gene is up-regulated in response to Prolactin stimulation. In this work, we studied the effects of Cyclosporine A and the competition with Prolactin on BRCA1 protein expression in vitro.

Methods: The expression of BRCA1 was monitored in a human breast cancer cell line (MCF7) by comparison with a normal breast epithelial one (MCF10a) treated with Cyclosporine A and ovine Prolactin. The amount of BRCA1 protein expression was quantified using a strategy of two successive affinity perfusion chromatographies.

Results And Conclusion: We showed that Prolactin in presence of Cyclosporine A has no effect on BRCA1 protein expression in human breast cell lines. This emphasized the hypothesis that BRCA1 may be stimulated by Prolactin.