Elevated expression of AKR1C3 leads esophageal cancer resistant to ionizing radiation via modulation of oxidative stress

With the aim to elucidate the etiology of radioresistance, we explored the genetic alterations in non-radioresistant vs. resistant esophageal cancer cells acquired by long-term fractionated radiation. We found AKR1C3, an aldo-keto reductase expressed seldom in most human tissues, expressed higher in radioresistance-acquired cells. Suppression of AKR1C3 via RNAi or its chemical inhibitors restored the sensitivity of the acquired tumor cells and xenograft nude mice to ionizing radiation (IR). We also found the potential involvement of AKR1C3 in removal of cellular ROS and explain, at least partially, the acquired radioresistance by AKR1C3 overexpression. Genome-wide profiling of gene expression in KY170R v. KY170 and TE13R v. TE13 using Illumine Human-6 V3 microarray indicated that over 900 genes were found to be remarkably differentiated. Among them, AKR1C3, an aldo-keto reductase existing at a low level in most human tissues, attracted our attention due to its significant expression in both radioresistant cells.