Isorhamnetin Promotes 53BP1 Recruitment through the Enhancement of ATM Phosphorylation and Protects Mice from Radiation Gastrointestinal Syndrome

Flavonoids are a subclass of polyphenols which are attractive, due to possessing various physiological activities, including a radioprotective effect. Tumor suppressor p53 is a primary regulator in the radiation response and is involved in the pathogenesis of radiation injuries. In this study, we revealed that isorhamnetin inhibited radiation cell death, and investigated its action mechanism focusing on DNA damage response. Although isorhamnetin moderated p53 activity, it promoted phosphorylation of ataxia telangiectasia mutated (ATM) and enhanced 53BP1 recruitment in irradiated cells. The radioprotective effect of isorhamnetin was not observed in the presence of ATM inhibitor, indicating that its protective effect was dependent on ATM. Furthermore, isorhamnetin-treated mice survived gastrointestinal death caused by a lethal dose of abdominal irradiation. These findings suggested that isorhamnetin enhances the ATM-dependent DNA repair process, which is presumably associated with the suppressive effect against GI syndrome

Evaluation of Cell Responses of <i>Saccharomyces cerevisiae</i> under Cultivation Using Wheat Bran as a Nutrient Resource by Analyses of Growth Activities and Comprehensive Gene Transcription Levels

Wheat bran has high nutritional values and is also cheaper than yeast nitrogen base as an important component of a medium. Although its use in microbial cultivations is expected, research and development has hardly progressed so far. In this study, with experimental Saccharomyces cerevisiae BY4741, the cell responses to wheat bran as a nutrient were evaluated by analyses of cell growth, ethanol production, and comprehensive gene transcription levels. Comparing wheat bran and yeast nitrogen base, BY4741 showed specific growth rates of 0.277 ± 0.002 and 0.407 ± 0.035 as a significant difference. Additionally, wheat bran could be used as a restricted media component like yeast nitrogen base. However, in 24 h of cultivation with wheat bran and yeast nitrogen base, although conversion ratios of ethanol productions showed no significant difference at 63.0 ± 7.2% and 62.5 ± 8.2%, the ratio of cell production displayed a significant difference at 7.31 ± 0.04% and 4.90 ± 0.16%, indicating a different cell response. In fact, the comprehensive evaluation of transcription levels strongly suggested major changes in glucose metabolism. This study indicated that BY4741 could switch transcription levels efficiently to use wheat bran

Topical steroid versus placebo for the prevention of radiation dermatitis in head and neck cancer patients receiving chemoradiotherapy: the study protocol of J-SUPPORT 1602 (TOPICS study), a randomized double-blinded phase 3 trial

Abstract Background To date, the clinical benefit of topical steroid use has only been demonstrated for radiation dermatitis induced by 50–60 Gy irradiation in breast cancer. However, these agents are also often used clinically for the control of radiation dermatitis induced by high-dose (>60Gy) irradiation with chemotherapy in head and neck cancer. Despite this, the prophylactic efficacy of topical steroids for radiation dermatitis induced by high-dose irradiation is still unclear. The aim of this study is to clarify the benefit of topical steroids in basic nursing care for radiation dermatitis induced by chemoradiotherapy in patients with head and neck cancer. Methods The study is being conducted as a multicenter 2-arm randomized double-blinded placebo-controlled Phase 3 trial in Japan. The study was started in May 2017, with participant enrollment between May 2017 and April 2019. Patients scheduled to receive definitive or postoperative chemoradiotherapy for head and neck cancer are eligible for enrollment. All patients will receive chemoradiotherapy, consisting of single agent CDDP and 70-Gy irradiation. Bilateral neck irradiation is mandatory. Supportive care for radiation dermatitis will consist of basic nursing care with topical steroid or placebo. When radiation dermatitis grade 1 is seen or total radiation dose reaches 30 Gy, minimally required intervention will be started as a first step. If radiation dermatitis worsens to grade 2, the irradiated area will be covered with a moderately absorbent surgical pad and steroid or placebo topical cream. The primary endpoint is a comparison of the proportion of patients with ≥ grade 2 radiation dermatitis by NCI Common Terminology Criteria for Adverse Events (CTCAE) Version 4.0. Ethical approval has been obtained from all participating sites. The results of this study will be submitted for publication in international peer-reviewed journals and the key findings will be presented at international scientific conferences. Discussion Evidence supporting the benefit of adding topical steroids in general nursing care for radiation dermatitis induced by high-dose irradiation with chemotherapy is insufficient. This trial aims to clarify the clinical benefit of topical steroid for radiation dermatitis induced by high-dose irradiation with chemotherapy. The trial is ongoing and is currently recruiting. Trial registration number UMIN000027161. Protocol version 3.0, 18 April 2017