Insight

Fall 2004

Thanks to NASA Grant, Cancer Biology Group Improving Basic Understanding of Leukemia

Almost a year ago, the Cancer Biology Group, housed within the Department of Environmental and Radiological Health Sciences, received a competitive grant from the National Aeronautics and Space Administration. The five-year, $9.7 million grant is helping researchers develop a better understanding of radiation risks to astronauts during deep-space travel and prolonged stays in space.

But the grant also is helping researchers understand the pathology of acute myelogenous leukemia (AML), one of the most common types of radiation-induced leukemia.

“Not many people are going to be venturing out into space, but the NASA grant gives us a real opportunity to study in depth the mechanisms for leukemia development, and that means improved diagnosis and treatment for people here on Earth,” said Dr. Robert Ullrich, Director of the Cancer Biology Group and of research for the Flint Animal Cancer Center . “Over the long run, this research will have much wider applications, including the development of bio-markers for earlier leukemia diagnosis and a greater understanding of the molecular changes that occur during the development of leukemia, which in turn could lead us to develop unique therapies.”

NASA’s concern is first and foremost the safety of astronauts participating in the agency’s space program, particularly those who may be traveling to Mars (a two- to three-year journey) or those staying for prolonged periods at the International Space Station. Though spacesuits and spacecraft keep astronauts alive and protect them from the near-zero gravity of space, they provide little protection from the unseen dangers of radiation.

“Space presents an unusual radiation environment, in which astronauts are exposed to energetic heavy ions that are more effective in causing lots of radiation effect compared to what we have here on Earth, where our atmosphere protects us from these particles,” said Dr. Ullrich. “One concern of this exposure is the possibility of damaging cells and setting up the body for the development of leukemia in ensuing years. Astronauts have accepted the acute risks of space flights – accidents or equipment failure that may cost them their lives – but having a life-long risk, a time bomb of sorts, is unacceptable to them or the NASA program.”

The only way to study these heavy ions on earth is to create them in large accelerators, as Dr. Ullrich and his team are doing at the Brookhaven National Laboratory on Long Island. Once the heavy ions are generated, researchers expose specially bred mice to the ions at varying doses. The researchers use mouse models to compare the effects of high-energy compounds, like the iron particles found in space, to the effects of the gamma rays most frequently associated with radiation-induced leukemia. These gamma ray studies come from patients with radiation exposure from cancer treatment, as well as older, existing data from survivors of the Nagasaki and Hiroshima atomic bombings at the end of World War II.

“We are exploring the cellular mechanisms affected by radiation exposure on a number of different levels so we can extrapolate animal studies to calculate human risk,” said Dr. Ullrich. “We are looking at molecular changes in mouse models and comparing these to similar changes in people exposed to radiation during cancer treatment.”

The Cancer Biology Group is partnering with research teams at the M.D. Anderson Cancer Center and the Baylor College of Medicine, both in Houston. One important part of the group’s work is developing new mouse models to study radiation effect. This includes reconstituting an immune-compromised mouse’s bone marrow using human cord blood so that living human blood cells can be studied in an animal model. Being able to study energetic heavy ion and gamma ray exposure on human blood cells in a living system will be invaluable, Dr. Ullrich said.

“This grant will enable us to develop a better understanding of leukemia, especially in cancer patients where therapeutic radiation can lead to leukemia as a secondary cancer,” said Dr. Ullrich. “We also will develop a clearer understanding of the long-term risks of radiation exposure. This wouldn’t be happening without ambitious research programs, like those funded by NASA. What is true of NASA in general is that we as a society have reaped so much benefit from the space program because of the needs of NASA complementing the needs of expanding biomedical research.”

Dr. Ullrich expects to see data coming out from the initial mouse studies in late winter or early spring. The Cancer Biology Group and its partners also will be meeting this fall to further plan the course of their investigations. The Cancer Biology Group is one of 14 Colorado State University Programs of Research and Scholarly Excellence, one of five such programs located within the College of Veterinary Medicine and Biomedical Sciences.