Author(s)

Spencer Keene, Charles Azuelos, Shyamal K. Majumdar^*

Department of Biology, Lafayette College, Easton, PA, USA.

Tamoxifen citrate (TAM) has been used to treat breast cancer in women for many years. The com-parative effects of TAM in inducing apoptosis were evaluated in estrogen receptor-positive (ER- positive MCF-7) and estrogen receptor-negative (ER-negative MDA-MB-231) human breast cancer cell lines in vitro in order to determine if these two cell lines differ in their sensitivity to TAM. Mi-tochondrial membrane permeability potential disruption was assessed in both cell lines by a lip-ophilic cationic dye (DePsipher assay, Trevigen, Inc.) utilizing fluorescence microscopy. Using this specific fluorochrome, we were able to associate mitochondrial membrane disruption to early, mid-, and late apoptotic cells. TAM induced cell death via apoptosis in both ER-positive and ER- negative cells, however, apoptosis induction was more pronounced in ER-positive MCF-7 compared to ER-negative MDA-MB-231 breast cancer cells. These findings may have some therapeutic use in the treatment of estrogen dependent and estrogen independent breast cancer.

Tamoxifen, Apoptosis, MCF-7 and MDA-MB-231 Human Breast Cancer Cell Lines, Mitochondrial Membrane Potential Assay, Estrogen Receptor

Keene, S. , Azuelos, C. and Majumdar, S. (2014) Sensitivity Evaluation of Two Human Breast Cancer Cell Lines to Tamoxifen through Apoptosis Induction. Open Journal of Apoptosis, 3, 70-77. doi: 10.4236/ojapo.2014.34008.