Radiotherapy, a common treatment for cancer, is one of the most effective ways to destroy cancer cells and shrink tumours. Around 50% of patients with tumours located in the gastrointestinal cavity (liver, pancreas, colon, prostate, etc) receive this type of treatment, which has increased cancer survival rates over the past decades. However, intensive radiation therapy not only damages tumour cells, but also healthy intestinal cells leading to toxicity in 60% of the treated patients. Whereas reversal of this toxicity is observed after radiotherapy has finished, 10% of the treated patients develop gastrointestinal syndrome, a disease characterised by intestinal cell death resulting in the destruction of the entire intestine and patient death.

Damage of healthy intestinal cells is the main disadvantage of radiotherapy leading to the discontinuation and failure of an efficient cancer treatment, potentially causing a quick tumour recurrence. Now, a discovery published in Science by scientists from the Growth Factors, Nutrients and Cancer Group at the Spanish National Cancer Research Centre (CNIO) might be useful to protect healthy intestinal cells from radiation damage. The consequences of their findings in mice might radically change the way humans manage exposure to high levels of radiation; both for cancer research and treatment as well as for other areas like space explorations, nuclear warfare or nuclear accidents.
 
The Group's work focuses on URI, a protein whose functions remain not yet fully understood. However, previous studies from the Group have found that abnormal levels of expression of this protein in certain organs can cause cancer. The study now published in Science shows that high levels of URI protein protect mice from radiation-induced intestinal damage, whereas low or no detectable levels of the protein can lead to gastrointestinal syndrome and death.
 
 
Image: In red, highly proliferative cells of the intestinal crypts; they are targeted by irradiation and die during radiotherapy. They are considered to be radiosensitive. In green, dormant stem cells with high levels of URI; they survive irradiation, become proliferative after irradiation to regenerate the damaged intestine.(Credit: CNIO)