Primary cultured human breast epithelial cells up-regulate protein disulfide isomerase in response to zeranol.

BACKGROUND

Experimental data at the molecular, cellular and organismal levels have implicated dietary components in cancer. Exposure to numerous growth factors, hormones and environmental agents, that can regulate signaling events, is involved in carcinogenesis. Research targets on gene-nutrient interactions may give useful information for the development of a novel diet-based intervention for the at-risk population.

MATERIALS AND METHODS

To examine the proteomic effect of a low level dietary compound on potential breast cancer, primary human breast epithelial cells were isolated and cultured in media with or without zeranol, an anabolic, non-estrogenic growth promoter with estrogenic activity, used in beef cattle and naturally found in some fungus in grain. The cells then underwent proteomic analysis.

RESULTS

2-D electrophoresis showed that protein disulfide isomerase (PDI) was up-regulated 5-fold in the breast epithelial cells exposed to zeranol. PDI has been shown to be up-regulated in a variety of cancerous tissues, although this is the first reported up-regulation of PDI in breast tissue.

CONCLUSION

PDI may be a useful marker of dietary exposure to zeranol.