Dissecting the role of ATRX in soft tissue sarcoma development and radiation response

摘要： 软组织肉瘤是结缔组织的肿瘤，估计有12,000例新发病例 每年都有癌症病例，尽管接受了治疗，但预后很差，五年存活率为50%。 提高软组织肉瘤患者治疗水平的一个重要研究目标是了解 基因突变如何影响软组织肉瘤的发展和辐射反应。有趣的是，接下来- 来自癌症基因组图谱和其他大规模癌症测序的世代测序数据 研究发现，阿尔法地中海贫血和X连锁智力低下(ATRX)排在第二位 软组织肉瘤中的频繁突变基因。ATRX最为人所知的可能是它作为 端粒交替延长(ALT)，一种端粒酶非依赖性的肿瘤维持机制 在所有人类癌症中发现了15%。有趣的是，ATRX对多发性骨髓瘤患者的总体生存有预测作用。 人类癌症和研究人员最近证实，ATRX基因敲除会导致放射增敏 在神经胶质瘤细胞系中。尽管该基因在多种人类癌症中具有明显的重要性，而且其频繁的 在软组织肉瘤中的改变，ATRX在软组织肉瘤中的作用仍未被研究。 该项目的长期目标是提高目前治疗软组织肉瘤的疗效。 并使治疗人类癌症的新疗法的开发成为可能。整体而言 本研究的目的是确定ATRX缺失对放射敏感性和先天免疫的影响。 软组织肉瘤的反应。为了实现这一点，Cre-loxP重组酶系统已经在 用基因工程小鼠模型建立第一个原代小鼠软组织肉瘤模型 ATRX删除。中心假设是ATRX的缺失会损害DNA损伤修复，延缓肿瘤 软组织肉瘤的发生和增加放射敏感性。为了验证这一假设，主要的软件 ATRX缺失的组织肉瘤将与保留ATRX的原发软组织肉瘤进行比较。 使用使用Cre-loxP和双重重组酶技术产生的体外和体内模型系统，I 我将在三个具体目标上检验这一假设： 目的1：探讨ATRX基因缺失对肿瘤生长及相关重复元件的影响 原发软组织肉瘤小鼠模型中的有丝分裂功能障碍 目的2：确定ATRX在DNA损伤修复和肉瘤对电离辐射反应中的作用 目的3：确定ATRX缺失在辐射诱导的有丝分裂功能障碍和cGAS-STING中的作用 肉瘤中的先天免疫信号

ABSTRACT: Soft tissue sarcomas are tumors of the connective tissue that account for an estimated 12,000 new cancer cases annually and carry a poor prognosis with a five year survival rate of 50% despite treatment. An important research objective in improving therapy for soft tissue sarcoma patients is to understand how genetic mutations affect soft tissue sarcoma development and radiation response. Intriguingly, next- generation sequencing data from The Cancer Genome Atlas and other massive cancer sequencing efforts have identified Alpha Thalassemia and Mental Retardation X-linked, or ATRX, as the second most frequently mutated gene in soft tissue sarcoma. ATRX is perhaps best known for its role as regulator of alternative lengthening of telomeres (ALT), a telomerase independent tumor maintenance mechanisms found in 15% of all human cancers. Interestingly, ATRX is predictive for overall survival in multiple human cancers and researchers recently demonstrated that ATRX knockdown leads to radiosensitization in glioma cell lines. Despite the clear importance of this gene in multiple human cancers and its frequent alteration in soft tissue sarcoma, the role of ATRX in soft tissue sarcoma remains relatively unstudied. The long term goal of this project is to improve the efficacy of current therapies for soft tissue sarcoma patients and enable the development of novel therapeutics for the treatment of human cancers. The overall goal of this proposal is to determine the effect of Atrx deletion on the radiosensitivity and innate immune response of soft tissue sarcoma. To achieve this, the Cre-LoxP recombinase system has been used in genetically engineered mouse models to generate the first primary mouse model of soft tissue sarcoma with ATRX deletion. The central hypothesis is that loss of ATRX impairs DNA damage repair, delays tumor development and increases radiosensitivity in soft tissue sarcoma. To test this hypothesis, primary soft tissue sarcomas with ATRX deletion will be compared to primary soft tissue sarcomas that retain Atrx. Using in vitro and in vivo model systems generated using Cre-LoxP and dual recombinase technologies, I will test this hypothesis in three specific aims: Aim 1: Investigate the effect of Atrx deletion on tumor growth and repetitive element associated mitotic dysfunction in a primary mouse model of soft tissue sarcoma Aim 2: Determine the role of ATRX in DNA damage repair and sarcoma response to ionizing radiation Aim 3: Determine the effect of Atrx deletion on radiation induced mitotic dysfunction and cGAS-STING innate immune signaling in sarcoma