Putting Humpty Dumpty Together Again

Female fertility may benefit from discovery of proteins that kill off egg cells

(RxWiki News) Women who beat cancer with the help of radiation or chemotherapy often damage their eggs in the process. But there may be a way to eventually prevent infertility.

A recent study found that blocking two proteins prevents egg cells from dying. In fact, the eggs can repair themselves and go on to produce healthy offspring.

"Ask your doctor about your fertility options."

The study, led by Jeffrey B. Kerr, PhD, of the Department of Anatomy and Developmental Biology at Monash University in Australia, offers information that could help with future fertility strategies for women who have gone through cancer treatment.

If the DNA of an egg cell becomes damaged, the egg cells usually die.

DNA damage might occur to an egg cell because of exposure to radiation or chemotherapy. The subsequent death of a woman's eggs can cause her infertility.

"This removal of damaged cells is a natural process that is essential to maintaining health but, for women undergoing cancer treatment, can be devastating when it leads to infertility," said co-author Clare Scott, from the Walter and Eliza Hall Institute of Medical Research, in a release about the study.

Now scientists have an idea of how that egg cell death occurs, which might allow them to begin working on a way to prevent it.

Two proteins, called PUMA and NOXA, appear to trigger the death of egg cells following DNA damage.

The scientists made this discovery through trials with mice who were exposed to radiation but were able to successfully reproduce afterward.

When the mice were bred with egg cells that were missing the PUMA protein, their eggs survived after radiation exposure.

One concern about the surviving eggs was whether the DNA damage could lead to problems with offspring, but the eggs were able to fix themselves.

"To our great surprise we found that not only did the cells survive being irradiated, they were able to repair the DNA damage they had sustained and could be ovulated and fertilized, producing healthy offspring," said Dr. Kerr in the release. "When the cells were also missing the NOXA protein, there was even better protection against radiation."

If researchers can figure out a way to block one or both of these proteins, they might be able to prevent the death of egg cells in humans as well.

Much more research would need to be done to determine how to turn off these proteins' effects in the ovaries and to ensure they would preserve healthy eggs in women.

However, this research offers a first step that allows scientists to explore a new option for women who have lost their fertility due to chemotherapy, radiation or possibly early menopause.

The study was published September 21 in the journal Molecular Cell. The research was funded by the National Health and Medical Research Council, the Cancer Council Victoria, the Leukemia and Lymphoma Society, the National Cancer Institute, the American Cancer Society and the Victorian Cancer Agency.

Review Date: 
September 24, 2012