Potential treatment for radiation-induced lung injury identified

Healthy mouse lung tissue (left), RLI tissue (middle), and tissue that received preventative treatment (right).

Although radiation is an important tool in the treatment of many cancer types, damage to some healthy lung tissue inevitably occurs. An estimated 15 percent of patients treated for lung cancer develop irreversible scarring of lung tissue, called radiation lung injury (RLI), a chronic, untreatable condition that can cause breathing difficulties and, in severe cases, death. This condition can progress even after radiation treatment has ended.

Researchers from the Center for Cancer Research’s Radiation Oncology Branch have identified a therapeutic target for the possible treatment of lung injury from radiation therapy. The study, led by physician-scientist Deborah Citrin, published December 22, 2016 in Scientific Reports and included team members from the Upstate Medical University in Syracuse, New York, Genentech, and the National Institute of Allergy and Infectious Diseases.

RLI appears to be caused by the body’s immune response to trauma, but the exact mechanism remains unclear.  In this study, the researchers zeroed in on the role of a cytokine called interleukin 13 (IL-13) because of its known involvement in the inflammatory response seen in asthma and a lung condition called pulmonary fibrosis that shows lung scarring similar to RLI.

Experiments in mice revealed that radiation therapy caused elevated levels of IL-13 and the accumulation of a subset of blood cells called macrophages in lung tissue that results in the development of RLI. In striking contrast, mice carrying a mutation that prevented IL-13 production by white blood cells did not develop RLI after radiation exposure. In a follow-up experiment, normal mice that produced IL-13 but received treatment with an antibody that neutralized IL-13 activity did not develop RLI.

The results suggest that IL-13 plays a crucial role in the development of RLI, and therapies designed to block IL-13 activity may halt its progression in patients who undergo radiation therapy. IL-13 may also serve as a biomarker for identifying patients in the early stages of RLI when therapeutic intervention would prove most effective.

Summary Posted: Thu, 12/01/2016