Protein May Hold Key to Cancer Radiation Treatments

Manipulating the molecule could boost the therapy's effectiveness, study suggests

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By Randy Dotinga
HealthDay Reporter

WEDNESDAY, Aug. 17, 2005 (HealthDay News) -- Like other cancer treatments, radiation isn't always a cure. Tumors can come back within months or years to wreak more havoc.

But now, researchers say they're gaining a better understanding of how to tinker with the body's biochemistry to make radiation more effective.

Manipulation of a protein known as HIF-1 seems to provide added protection against the return of cancer after radiation treatment, according to a new study involving mice.

The "trick," said study author Dr. Mark W. Dewhirst, is to avoid turning the protein into a villain that actually makes it harder to control the cancer.

The research won't provide immediate benefits to cancer patients. But scientists are currently researching several drugs that may be able to control the protein, said Dewhirst, a professor of radiation oncology at Duke University.

Along with chemotherapy, radiation is a routine treatment for cancer. Contrary to popular belief, radiation doesn't burn tumors. Instead, the energy produced by radiotherapy damages the DNA inside cells, making them die, Dewhirst said.

But radiation doesn't always work. Both radiation and chemotherapy can boost the levels of the HIF-1 protein, a "master switch" that controls more than 70 other proteins that govern cellular tasks, Dewhirst said. In the process, HIF-1 can keep cancer cells alive by protecting blood vessels that feed tumors.

But the HIF-1 protein can also help by making the cancer cells more vulnerable to radiation, Dewhirst said.

In the new study, Dewhirst and a colleague tried to unravel the workings of the protein by conducting experiments on mice. They report their findings in the August issue of Cancer Cell.

The researchers reported that blocking HIF-1 immediately after radiation treatment helped boost the amount of time before the tumors returned.

Scientists plan to see if their theories about HIF-1 hold true during chemotherapy treatment, and tests of drugs that target the protein should begin in humans later this year, Dewhirst said.

But years of research will be needed to understand the HIF-1 protein, Dewhirst said. "We are far from knowing everything there is to know about it."

More information

Learn more about radiation therapy from the National Cancer Institute.

SOURCES: Mark W. Dewhirst, D.V.M., Ph.D., Gustavo S. Montana professor of radiation oncology and professor, pathology and biomedical engineering, Duke University, Durham, N.C.; August 2005 Cancer Cell

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