Inhibition of Tamoxifen-Resistant Breast Cell Proliferation by Vitamin D3 [Poster Abstract # M-L64]Molecular Biology of the Cell (2008)
Breast cancer is the most common non-skin cancer in the United States, leading to the second highest in cancer-associated deaths in women. Most breast cancers initially develop with a strong dependency on estrogens, which implies estrogen contributes to proliferation of cancer cells. This type of cancer is often treated with anti-estrogens, such as tamoxifen. Tamoxifen is a selective estrogen receptor modulator (SERM) that competes with estrogen for the binding of the receptor. Although tamoxifen has produced some success, prolonged treatment with tamoxifen has often resulted in tamoxifen resistance. The exact mechanism of how breast cancer cells develop resistance is unclear. To better study the development of anti-estrogen resistance, our lab has developed a tamoxifen resistant breast cancer cell line MCF7-TamR. Preliminary data suggest that MCF7-TamR cells expressed lower levels of Vitamin D3 Receptor (VDR). High levels of VDR have been associated with decreased breast cancer cell growth, suggesting low levels of VDR may be important for the development of tamoxifen resistance. In order to better understand the role of VDR in tamoxifen resistance, we treated both cell lines with 1,25 dihydroxyvitamin D3 and demonstrated that resistant cells are more sensitive to the inhibitory effects of vitamin D3. This suggests that vitamin D3 may serve as a potential therapeutic agent for tamoxifen resistant breast cancer. However, further studies are necessary to attain a better understanding of how vitamin D3 and VDR contribute to tamoxifen resistance.
Citation InformationC. L. Siewit, R. Chow, F. Firanescu, I. Hansen, et al.. "Inhibition of Tamoxifen-Resistant Breast Cell Proliferation by Vitamin D3 [Poster Abstract # M-L64]" Molecular Biology of the Cell Vol. 19 Iss. Supplement (2008) p. 48 ISSN: 1059-1524
Available at: http://works.bepress.com/maggie_louie/27/