Takamitsu Morioka1, Shunsuke Yamazaki2, Hiromi Yanagihara2, Masaaki Sunaoshi2, Mutsumi Kaminishi, Shizuko Kakinuma2. 1. Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan morioka.takamitsu@qst.go.jp kakinuma.shizuko@qst.go.jp. 2. Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan.
Abstract
BACKGROUND/AIM: Progress in cancer treatment and diagnosis has made second cancer after medical radiation exposure a particular concern among childhood cancer survivors. Calorie restriction (CR) is a broadly effective cancer prevention strategy, although its effects on radiation-induced intestinal tumours are unclear. Here we examined the cancer-preventative efficacy of a CR diet at different starting ages on radiation induction of intestinal tumours in mice. MATERIALS AND METHODS: Male C3B6F1 ApcMin/+ mice were irradiated with 0 or 2 Gy of X-rays at 2 weeks of age. After an interval of 2, 8 or 18 weeks, mice were fed with a non-CR (95 kcal/week/mouse) or CR (65 kcal/week/mouse) diet. Intestinal tumours were evaluated for number, size distribution and malignancy. RESULTS: CR suppressed the size and progression of both spontaneous and radiation-induced intestinal tumours depending on age at starting of CR. CR diets were effective even administered to adult mice. CONCLUSION: CR was effective for suppression of tumour progression, which was accelerated by radiation exposure. Use of CR might be a useful cancer-prevention strategy for radiation-induced tumours of the intestinal tract.
BACKGROUND/AIM: Progress in cancer treatment and diagnosis has made second cancer after medical radiation exposure a particular concern among childhood cancer survivors. Calorie restriction (CR) is a broadly effective cancer prevention strategy, although its effects on radiation-induced intestinal tumours are unclear. Here we examined the cancer-preventative efficacy of a CR diet at different starting ages on radiation induction of intestinal tumours in mice. MATERIALS AND METHODS: Male C3B6F1 ApcMin/+ mice were irradiated with 0 or 2 Gy of X-rays at 2 weeks of age. After an interval of 2, 8 or 18 weeks, mice were fed with a non-CR (95 kcal/week/mouse) or CR (65 kcal/week/mouse) diet. Intestinal tumours were evaluated for number, size distribution and malignancy. RESULTS:CR suppressed the size and progression of both spontaneous and radiation-induced intestinal tumours depending on age at starting of CR. CR diets were effective even administered to adult mice. CONCLUSION:CR was effective for suppression of tumour progression, which was accelerated by radiation exposure. Use of CR might be a useful cancer-prevention strategy for radiation-induced tumours of the intestinal tract.