Enhancement of the radiation effects by D-allose in head and neck cancer cells.

The aim of this study was to investigate the radiosensitizing potential of D-allose in human head and neck cancer cells. HSC-3 cells were treated with or without D-allose for 6 h and then irradiated (2-6 Gy). The combination of D-allose and radiation was more effective than either agent alone. The radiation enhancement ratios at the 37% survival level were 1.61 and 2.11 for 10 mM and 25 mM D-allose treatment, respectively. The combination of D-allose and radiation also reduced the cell proliferation in 3D culture experiments. Although the mRNA expression of TXNIP was not increased by radiation alone, combined use with D-allose markedly elevated TXNIP expression. The combination of D-allose and radiation significantly induced intracellular reactive oxygen species (ROS) and apoptosis compared to that induced by either agent alone. This study shows that D-allose enhances the effect of radiation, suggesting a potential clinical application of combination treatment with D-allose and radiation for head and neck cancer.