Targeting the ATR pathway in p53-deficient cancers

描述（由申请人提供）：含有失活p53突变的癌细胞表现出检查点缺陷和受损的DNA损伤反应。由于p53突变在许多常见癌症中普遍存在，因此利用这些缺陷的策略预计会产生重大的临床影响。这一建议的重点是ATR途径，它最近被认为是p53缺陷癌细胞对治疗药物反应的关键调节剂。ATR激酶全酶被DNA损伤和DNA复制胁迫激活，因此对目前使用的许多抗癌药物有反应。最近的研究揭示了控制ATR的新机制。这些见解为针对这一途径提供了新的机会。本项目采用遗传和生物化学方法来研究确定ATR复合物的蛋白质-蛋白质相互作用，以及常用化疗药物对复合物形成的影响。针对ATR通路上下游不同组分（包括Cdk2和Chk1）的有效性将在体外和体内进行比较评估。在协调的努力下，将筛选一系列已批准的药物以确定新的ATR激活剂。具有靶向基因改变的人类体细胞将用于鉴定新的药物/靶标组合。一项重点工作将是筛选对顺铂有促进生存反应的基因。顺铂是一种抗癌药物，最近被发现可以在缺乏p53的细胞中诱导不同的生存途径。该项目的长期目标是揭示ATR调控的基本机制，新的药物靶点，以及在p53缺乏的人类癌细胞中产生合成致死性的新策略。

DESCRIPTION (provided by applicant): Cancer cells that harbor inactivating p53 mutations exhibit checkpoint defects and impaired DNA damage responses. Because p53 mutations are prevalent in many common cancers, strategies that would exploit these defects are predicted to have significant clinical impact. This proposal is focused on the ATR pathway, which has recently emerged as a critical modulator of p53-deficient cancer cell survival in response to therapeutic agents. The ATR kinase holoenzyme is activated by DNA damage and DNA replication stress, and is therefore responsive to many of the anticancer agents currently in use. Recent studies have revealed new mechanisms by which ATR is controlled. These insights provide new opportunities to target this pathway. This proposed project employs genetic and biochemical methods to study the protein-protein interactions that define the competent ATR complex, and the effects of common chemotherapeutic agents on complex formation. The effectiveness of targeting distinct upstream and downstream components of the ATR pathway, including Cdk2 and Chk1, will be comparatively evaluated in vitro and in vivo. In a coordinated effort, a pharmacogenetic array of approved drugs will be screened to identify new ATR activators. Human somatic cells with targeted genetic alterations will be used to identify new drug/target combinations. A focused effort will be made to screen for genes that promote survival in response to cisplatin, an anticancer drug recently found to induce distinct survival pathways in cells that are deficient for p53. The long-term objectives of this project are to reveal basic mechanisms of ATR regulation, new drug targets, and new strategies for generating synthetic lethality in p53-deficient human cancer cells.