Disintegrating sugars are bringing researchers a step closer to understanding how tumours are destroyed by radiation therapy.

Irradiation with fast protons or heavy ions is a common treatment for malignant tumours. The treatment damages DNA in cancerous cells, but the mechanism is largely unexplored at the biological level. Thomas Schlathölter and colleagues at the University of Groningen, the Netherlands, have found that DNA damage is dominated by the disintegration of deoxyribose, a sugar found in the backbone of the DNA double helix. 

The group used an ion beam to bombard deoxyribose molecules with a stream of fast heavy ions and protons. The irradiation split the molecules into small fragments, which were detected by time-of-flight spectrometry. The fragmentation pattern followed a power law, meaning the fragmentation occurs in a statistical, and therefore predictable, manner. The researchers compared the deoxyribose fragmentation pattern with that of adenine, one of DNA's complementary bases, and found that adenine is significantly more stable than the sugar.

This research appreciably advances our understanding of how irradiation kills tumour cells, said group member Fresia Alvarado. Future investigations will look to correlate what happens in isolated molecules with more realistic and complex systems like cells and organisms, she said.

Nina Athey-Pollard