Arresting a Radiation Robber

Radiation therapy before, during or after surgery is the standard of care in treating a number of cancers. Researchers have discovered a protein that works against this therapy.

Scientists have known that the protein cyclin D1 makes a number a cancers grow out of control. Dana-Farber Cancer Institute researchers now know that this same protein helps cancer cells repair from the DNA damage the radiation causes, making the therapy ineffective.

Ask your doctor is radiation therapy will work for you.

Siwanon Jirawatnotai, PhD, the lead author of the paper, says if cyclin D1 can be blocked, treatments for a variety of cancers may be improved. Cyclin D1 normally functions to control cell growth. When there are mutations in this protein, it causes cells to grow too much, a process that leads to tumor development.

Elevated levels of cyclin D1 are common in a number of cancers, including those of the breast, colon and prostate as well as in lymphoma and melanoma.

The new findings were uncovered in a series of experiments designed to zero in on the role of cyclin D1 in human cancer cells. Unexpectedly, researchers found that the protein was latching on to (binding with) a number of other proteins whose jobs are to repair DNA damage.

Using molecular tools, Jirawatnotai and his team lowered the levels of D1. Cancer cells with lower amounts of the protein responded better to radiation.

Drugs that target cyclin D1 are currently being tested in clinical trials. The goal is to develop medications that block cyclin D1 from promoting cancer cell growth.

Jirawatnotai says this discovery may help to more effectively treat a variety of cancers.

Peter Sicinski, M.D., Ph.D. is senior author of the report and a professor of genetics at Dana-Farber The report was published in the journal Nature.