Using transparent zebrafish embryos, researchers at Jefferson Medical College have shown that a microscopic nanoparticle can help fend off damage to normal tissue from radiation.
The nanoparticle, a soccer ball-shaped, hollow, carbon-based structure known as a fullerene, acts like an "oxygen sink," binding to dangerous oxygen radicals produced by radiation.
The scientists, led by Adam Dicker, M.D., Ph.D., associate professor of radiation oncology at Jefferson Medical College of Thomas Jefferson University in Philadelphia and at Jefferson's Kimmel Cancer Center, and Ulrich Rodeck, M.D., professor of dermatology at Jefferson Medical College, see fullerenes as a potentially "new class of radioprotective agents."
They present their team's results November 15, 2005 at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics in Philadelphia.
While chemotherapy and radiotherapy are the standard treatments for cancer, they take their respective toll on the body. Radiation can damage epithelial cells and lead to permanent hair loss, among other effects, and certain types of systemic chemotherapy can produce hearing loss and damage to a number of organs, including the heart and kidneys. Some other side effects include esophagitis, diarrhea, and mouth and intestinal ulcers.
Only one drug, Amifostine, has been approved to date by the federal Food and Drug Administration, to help protect normal tissue from the side effects of chemotherapy and radiation, and researchers would like to develop new and improved agents.
Dr. Dicker and his group were exploring the molecular mechanisms responsible for cellular damage from radiation. They collaborated with a Houston-based drug company, C Sixty, and its radiation-protective agent, CD60_DF1.
To test how well it worked, they turned to tiny zebrafish embryos, which are transparent and allow scientists to closely observe damage produced by cancer treatments to organs. Zebrafish usually have most of their organs formed by day three of life.
They gave the embryos different doses of ionizing radiation as well as treatment by either Amifostine, which acted as a control agent, or CD60_DF1. They found that CD60_DF1 given before and even immediately after – up to 30 minutes – exposure to X-rays reduced organ damage by one-half to two-thirds, which was as good as the level of protection given by Amifostine.