Antagonism between estradiol and progestin on Bcl-2 expression in breast-cancer cells

✍ Scribed by Mustapha Kandouz; Marcella Siromachkova; Denis Jacob; Bertrand Chretien Marquet; Amu Therwath; Anne Gompel

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: French
• Weight: 664 KB
• Volume: 68
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/(sici)1097-0215(19960927)68:1<120::aid-ijc21>3.0.co;2-e

✦ Synopsis

Bcl-2 is a key protein involved in the control of apoptosis. Our previous studies on breast and endometrium indicated hormonal regulation of bcl-2 in these tissues. In the present work we have analyzed Bcl-2 and Bax protein expressions in MCF-7 and T47-D, 2 hormone-dependent breast-cancer cell lines, by immunoblott. Estradiol markedly increased Bcl-2 protein con- tent, both in short-and in long-term treatments of MCF-7 cells. Two types of anti-estrogens (4-hydroxytamoxifen and RU 58668) were able to reverse this effect. Also, a synthetic progestin (ORG 2058) was able to decrease the Bcl-2 level in T47-D cells. The level of Bax protein, however, was not affected in the same conditions of hormonal treatments. The level of Bcl-2 expression was 4.5-fold higher in MCF-7 than in MDA-MB 231 (an estradiol-independent cell line). From these results, we infer the existence of hormonal regulation of Bcl-2 expression and evoke a novel role for estradiol and progestin in the genesis of breast cancer.