bcl-2 and tamoxifen-induced apoptosis

Excerpt

Tamoxifen (TAM) is commonly used for adjuvant therapy of breast cancer, and is believed to work by competing with estrogen for binding to the estrogen receptor (ER). It has been suggested that TAM may exert its anti-proliferative effects by inducing apoptosis. The bcl-2 family of genes are associated with apoptosis, with the gene products bcl-2, bcl-X_L being inhibitors, while others such as bax are inducers of cell death. Apoptosis is controlled by the ratio of the various bcl-2 family members. Overexpression of HER2 in ER-positive MCF7 cells has been shown to suppress tamoxifen-induced apoptosis by up-regulating bcl-2 and bcl- X_L protein. However, it is not known whether TAM directly modulates bcl-2, bax or bcl-X_L. …