Drug protects mice, monkeys from radiation damage

By Julie Steenhuysen

CHICAGO (Reuters) - An experimental drug helped protect mice and monkeys from the damaging effects of radiation, researchers said on Thursday, in a finding that may lead to less toxic cancer treatments or an emergency treatment for radiation exposure.

They said the drug protected animals' bone marrow and cells in the gut from being destroyed by radiation without interfering with radiation therapy's ability to fight cancer.

"These tissues fail because these cells choose to commit suicide. Our idea was to block these suicidal intentions," said Andrei Gudkov of the Roswell Park Cancer Institute in Buffalo, New York, whose study was published in the journal Science.

Gudkov, who also is chief scientific officer at Cleveland BioLabs Inc which is developing the drug, said radiation triggers cells to undergo a type of programmed cell death know as apoptosis, which helps rid the body of defective cells.

Tumors have figured out how to block this suicide mode. "Tumors simply throw it out by causing mutations," Gudkov said in a telephone interview.

He and colleagues decided to study this mechanism to find a way to protect cells from radiation damage. They developed a compound known as CBLB502 made from a salmonella protein that naturally makes cells resistant to cell suicide.

A single dose of the drug given to the animals shortly before receiving radiation therapy significantly reduced damage to sensitive bone marrow and gastrointestinal cells and prolonged their survival.

The drug also improved survival of mice when given an hour after the animals got a dose of radiation.