Sex differences in DNA damage response

摘要： 一个人的性别与各种健康状况的频率、反应、 疾病治疗、药物相关毒性的发生率和寿命。当前文献 关于DNA损伤反应的性别依赖性差异仍然不清楚和矛盾， 特别是涉及DNA损伤剂，如放射治疗（RT）， 超过一半的新诊断癌症的治疗。因此，药效学（PD）生物标志物 基于DNA损伤终点的评估可能证明不仅在翻译和 临床癌症研究，但在标准的RT实践。目前，缺乏可靠的经验证的PD 可以量化细胞对DNA损伤的反应的生物标志物。共济失调毛细血管扩张突变激酶 (ATM)通过分子间自磷酸化被DNA双链断裂（DSB）激活 丝氨酸-1981。ATM丝氨酸-1981磷酸化（p-ATM）在暴露于砷的细胞中增加>50%。 只有5cGy的γ射线。这种灵敏度/化学计量表明，p-ATM可能是一种合适的， 辐射诱导的DNA损伤的可靠PD生物标志物。因此，我们开发了一种适合目的的 定量多重测定以分析p-ATM和pan ATM蛋白。该试验记录了 首次报道了在放疗或化疗后在患者PBMC中诱导p-ATM。到 为了解决ATM激活的性别差异，我们从男性和女性志愿者中获得PBMC， 测量ATM的正常基础水平以及离体照射后的ATM活化。 从女性分离的PBMC对p-S1981-ATM表达的诱导比男性高2.6倍 因此，RT诱导的p-ATM在雄性和雌性之间可能不同， 女性患者，这种差异可能表现为不同的反应和/或毒性， 临床设置。我们假设ATM在丝氨酸-1981的磷酸化是一个敏感的PD生物标志物 DNA损伤反应能够定义性别差异和RT毒性。为了解决这个 假设，我们在本申请中提出了两个具体目标。目的1将量化DNA损伤信号传导 目的2将评估和评估来自接受RT的男性和女性癌症患者的PBMC中的细胞凋亡和修复。 在离体DNA损伤后定量从正常受试者获得的分选的PBMC中的DNA损伤信号传导 识别辐射最易诱发的特定免疫细胞群的方法。完成这些 目的是验证p-ATM作为接受RT的患者中DNA损伤和修复的生物标志物， 推进p-ATM作为辐射毒性的生物标志物，可以减少剂量， 可以完成他们的治疗

Abstract: The sex of an individual has been associated with the frequency of various health conditions, responses to disease treatment, incidence of drug-associated toxicities, and lifespan. The current literature remains unclear and conflicting with regard to sex-dependent differences in DNA damage response, especially as it relates to DNA damaging agents, such as radiation therapy (RT) which is an indicated treatment in more than half of newly diagnosed cancers. Thus, pharmacodynamic (PD) biomarkers based on assessment of DNA damage endpoints may prove valuable not only in translational and clinical cancer research but in standard RT practices. Presently, there is a lack of robust validated PD biomarkers that can quantify cellular responses to DNA damage. Ataxia telangiectasia mutated kinase (ATM) is activated by DNA double-strand breaks (DSBs) through intermolecular autophosphorylation on serine-1981. ATM serine-1981 phosphorylation (p-ATM) is increased >50% in cells exposed to as little as 5 cGy γ-rays. This sensitivity/stoichiometry suggest that p-ATM may be an appropriate and reliable PD biomarker of radiation-induced DNA damage. Thus, we developed a fit-for-purpose quantitative multiplexed assay to analyze p-ATM and pan ATM protein. This assay documented the first reported induction of p-ATM in patient PBMCs following radiation therapy or chemotherapy. To address sex differences in ATM activation, we obtained PBMCs from male and female volunteers and measured the normal basal levels of ATM as well as the ATM activation following ex vivo irradiation. PBMCs isolated from women have a 2.6-fold greater induction of p-S1981-ATM expression than men following exposure to 2 Gy IR. It is therefore likely that RT-induced p-ATM will differ between male and female patients and that this difference may manifest as different responses and/or toxicities in the clinical setting. We hypothesize that ATM phosphorylation at serine-1981 is a sensitive PD biomarker of DNA damage response capable of defining sex differences and RT toxicities. To address this hypothesis, we propose two specific aims in this application. Aim 1 will quantify DNA damage signaling and repair in PBMCs from male and female cancer patients receiving RT. Aim 2 will evaluate and quantify DNA damage signaling in sorted PBMCs obtained from normal subjects following ex vivo DNA damage to identify specific immune cell populations most induced by radiation. Completion of these Aims will validate p-ATM as a biomarker of DNA damage and repair in patients receiving RT and advance p-ATM as a biomarker of radiation toxicity that may allow dose reduction such that patients experiencing toxicity can complete their therapy.