Population Council Research that makes a difference

One of ten new cancers diagnosed worldwide each year is breast cancer. By 2020, 70 percent of all breast cancer cases will occur in developing countries, where treatment and cure are out of reach for most women.

At the Population Council's Center for Biomedical Research, scientists are working to develop a new contraceptive that makes use of the progesterone receptor modulator compound ulipristal, which prevents breast cell multiplication and hence may help prevent breast cancer. Current studies are focusing on the possibility of the protective effects of the compound on the breast as well as studying its effects on the endometrium. The Population Council is developing ulipristal in a vaginal ring as a long-acting contraceptive.

Reproductive hormones, such as estrogen and progesterone, influence women's risk for breast cancer because they affect the way cells grow and divide. Ulipristal targets a breast cell protein known as the progesterone receptor that usually binds to progesterone. Council scientists are studying what happens to breast tissue when the progesterone receptor binds instead to ulipristal. Our studies, which use an experimental human breast cell model that incorporates either normal breast cells or breast cancer cells, suggest that ulipristal reduces the abnormal cell duplication and growth seen in cancer, and that normal human breast cells are not harmed by long-term exposure to the compound.

KeumSil Hwang, a cell and molecular biologist, determined that ulipristal regulates a cellular chemical process called SUMOylation. We are testing the hypothesis that by regulating SUMOylation with ulipristal, we can change the form of the progesterone receptor and thereby arrest the growth of breast tumor cells or, ideally, prevent their emergence altogether.

So far, researchers are hopeful about the studies, which have great potential to make contraceptive delivery systems safer and more effective in the prevention of unwanted pregnancy, and bringing additional health benefits such as contributing to breast health by arresting the potential emergence of tumor cells.