Structural studies of metazoan origin licensing

项目摘要 由于肿瘤的异质性，开发有效的癌症治疗仍然是一个重大挑战。 生理学，对非癌细胞的细胞毒性，以及耐药性的出现，所有这些都阻碍了 积极的患者结局。因此，迫切需要具有替代机制的新型抗癌剂 的行动。靶向DNA复制起始途径是癌症治疗的一个未充分探索的策略。 起源许可，DNA复制起始的第一步，在此期间复制解旋酶Mcm 2 -7被激活。 装载到复制起点上的，是特别感兴趣的，因为它的抑制是选择性细胞毒性的， 癌细胞系。然而，尚未开发出用于临床治疗的来源许可抑制剂， 部分原因是对后生动物中DNA复制起始机制的理解不完全。违反 S.酿酒酵母，它已被广泛用于研究复制起始在生化和 结构水平，没有后生动物来源的结构许可中间体含有Mcm 2 -7的途径上， 解旋酶加载已被解决。小分子来源许可抑制剂如何结合和抑制Mcm 2 -7 加载因子同样是未知的。这些知识上的空白阻碍了有效药物的开发 靶向复制起始的候选物。本提案的目标是揭示结构性见解， 后生动物起源许可证。深入了解后生动物的起源许可将有助于 靶向DNA复制起始复合物的小分子抑制剂的开发， 定义这些抑制剂的作用机制。这些结果将有助于实现长期目标 开发一种新的抗癌药物。

Project Summary Developing effective cancer therapies remains a significant challenge due to the heterogeneity of tumor physiology, cytotoxicity towards non-cancer cells, and the emergence of drug resistance, all of which hamper positive patient outcome. Thus, there is a critical need for novel anticancer agents with alternate mechanisms of action. Targeting the DNA replication initiation pathway is an underexplored strategy for cancer therapy. Origin licensing, the first step of DNA replication initiation during which the replicative helicase Mcm2-7 is loaded onto replication origins, is of particular interest because its inhibition is selectively cytotoxic towards cancer cell lines. However, no origin licensing inhibitors have been developed for clinical therapy yet, which is in part due to an incomplete mechanistic understanding of DNA replication initiation in metazoans. Contrary to S. cerevisiae, which has been used extensively to study replication initiation both at the biochemical and structural level, no structures of metazoan origin licensing intermediates containing Mcm2-7 on-pathway to helicase loading have been solved. How small-molecule origin licensing inhibitors bind and inhibit Mcm2-7 loading factors is likewise unknown. These gaps in knowledge have impeded the development of effective drug candidates targeting replication initiation. The goal of this proposal is to uncover structural insights into metazoan origin licensing. A deep understanding of metazoan origin licensing will aid in the development of small-molecule inhibitors targeting DNA replication initiation complexes and in defining the mechanisms by which these inhibitors act. These results will contribute to the long-term goal of developing origin licensing inhibitors as a new class of cancer drugs.