NEW YORK (Reuters Health) – Treatment with angiogenesis inhibitors may overcome the resistance that tumors often develop to radiotherapy, according to results of an animal study reported in the June 7th online issue of The Journal of Clinical Investigation.

Previous research has shown that tumors can develop resistance to radiation by increasing vessel formation through hypoxia-inducible factor 1 (HIF-1)-regulated cytokines.

In the current study, Dr. Claire Magnon, from Mount Sinai School of Medicine in New York, and colleagues show that combining radioiodide therapy with angiogenic inhibitors, like canstatin, can overcome HIF-1-dependent tumor survival pathways and enhance tumor cell apoptosis in vitro and in a murine mammary tumor model.

The results indicate that angiogenesis inhibitors can play a key role in shifting radiation-induced HIF-1 activity from promoting radioresistance to causing apoptosis, the authors state.

"This study provides a basis for developing new biology-based clinically relevant strategies to improve the efficacy of radiation oncology, using HIF-1 as an ally for cancer therapy," Dr. Magnon’s team concludes.