Progestins Stimulate Growth Factor Production In Cancer Cells.(breast cancer)

2001 JUN 7 - (NewsRx Network) -- by Sonia Nichols, senior medical writer - New research suggests progestins, natural or synthetic hormones that act like progesterone, cause some breast cancer cells to produce a growth factor associated with tumor growth and progression.

In recent years, researchers have begun to look at new ways to fight cancer by stopping the growth of new blood vessels that supply tumors with nourishment. They have identified one growth factor in particular, VEGF (vascular endothelial growth factor), that sends out strong signals encouraging the formation of these blood vessels.

According to researchers at the University of Texas Health Science Center in Houston, elevated levels of progestin increase the VEGF expression in breast cancer cells, making progestin inhibition a potential strategy for treating certain forms of breast cancer.

In the latest study, Salman M. Hyder and associates used a breast cancer cell line called T47-D to study the effects of progestin administration on VEGF expression.

Although VEGF expression in cells without added progestin was low, when progestin was given its expression increased by two- to fivefold within a few hours, based on tests for genetic expression of VEGF in molecules called mRNA.

Researchers found they could stop progestin-associated induction of VEGF by administering the anti-progesterone drug RU-486 to the breast cancer cells, indicating an important role for progesterone receptors in the induction process.

Only progesterone produced this effect; other hormones such as estrogens, glucocorticoids, and androgens did not encourage ...