THE ROLE OF TAMOXIFEN IN HUMAN BREAST CANCER MCF-7 CELLS THAT OVEREXPRESS PCDGF.

Nitin K. Sardana¹, Ginette Serrero Ph.D.²

¹Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 ²Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore.

This study was conducted to investigate whether in vitro, the anti-estrogen tamoxifen promoted growth in MCF-7 cells that overexpress PCDGF (O4), while it inhibited growth in MCF-7 cells that do not overexpress PCDGF (EV). PCDGF is a growth factor found to be overexpressed in many human breast cancer cells. It has been found that E2 stimulates PCDGF expression. Current in vivo studies have shown that tamoxifen can promote growth in MCF-7 cells overexpressing PCDGF(O4) rather than inhibit. O4 and EV transfected cells were plated in depleted medium, stripped serum, and E2. The cells were then collected and counted at least four times until day 7. In this long term growth assay, results showed that O4 cells with tamoxifen grew faster and to a greater extent than did O4 cells without tamoxifen. The results also showed that tamoxifen inhibited growth in EV cells. Although it is currently unclear how tamoxifen promotes growth in O4 cells, it can be concluded from this study that it does so in vitro as well as in vivo