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, breas t and ovarian cancer susceptibility gene is up-regulated in response to Pro lactin stimulation. In this work, we studied the effects of Cyclosporine A and the competition with Prolactin on BRCA1 protein expression in vitro. Me thods: The expression of BRCA1 was monitored in a human breast cancer cell line (MCF7) by comparison with a normal breast epithelial one (MCF10a) trea ted with Cyclosporine A and ovine Prolactin. The amount of BRCA1 protein ex pression was quantified using a strategy of two successive affinity perfusi on chromatographies. Results and conclusion: We showed that Prolactin in pr esence of Cyclosporine A has no effect on BRCA1 protein expression in human breast cell lines. This emphasized the hypothesis that BRCA1 may be stimul ated by Prolactin.