Therapeutic potential of FANCM for BRCA1-linked cancer

项目总结/摘要 乳腺癌和卵巢癌是全世界女性最常见的癌症之一。 显示出治疗BRCA相关癌症的潜力，通过一种利用 人力资源缺陷。然而，肿瘤通常会对这些药物和其他药物产生耐药性。因此，有一个紧迫的 我们需要找到新的针对BRCA相关癌症的靶向治疗方法。基因组不稳定是癌细胞的一个标志 也是肿瘤发生的潜在来源基因组不稳定的一个主要原因是复制叉停滞在位点 DNA损伤或DNA结构异常。在哺乳动物停滞叉修复的研究中， 缺乏工具来分析这个过程的分子细节。斯卡利实验室解决了这个问题， 适应大肠杆菌Tus/Ter复制叉屏障（RFB）以诱导位点特异性复制叉 在哺乳动物染色体上停滞 Tus/Ter阻断可特异性诱导缺乏BRCA 1的原代细胞中的串联重复（TD）， 通过常规的双链断裂（DSB），表明停滞的叉反应的特异性。有趣的是， 缺乏BRCA 1的乳腺癌和卵巢癌同样获得大量的小（~10 kb）TD，我们 被称为“组1”TD。因此，Tus/Ter系统概括了BRCA 1特异性调节， 组1在人乳腺癌和卵巢癌中观察到TD形成。我发现叉子电机熄火了 蛋白质-FANCM（范可尼贫血[FA] M组基因的产物）与BRCA 1协同作用， 抑制Tus/Ter诱导TD。此外，我发现了一种新的合成致命的相互作用之间的Brca 1 以及小鼠胚胎干（ES）细胞以及乳腺癌和卵巢癌细胞中的Fancm缺失。这些发现 提示FANCM可能是BRCA 1相关乳腺癌和卵巢癌有希望的治疗靶点。 我在这个提案中的目标是描绘新的FANCM-BRCA 1合成致命的相互作用在癌细胞中 并确定合成致死（Aim 1）的机制。此外，我将探索染色质环境 和蛋白质动力学，并将研究如何改变这些过程有助于 FANCM-BRCA 1合成致死相互作用（Aim 2）。我观察到Fancm及其下游的上位作用 靶向Tus/Ter的Fancd 2在促进无错误修复和抑制易错修复中的关键作用。 Fancm和Fancd 2在停滞分叉处的修复途径选择中的作用提高了它们可能具有相似的 与Brca 1的基因相互作用。将确定FANCD 2的各个结构域如何在修复途径中发挥作用 选择停滞的分叉及其与Brca 1的遗传相互作用（Aim 3）。这一整体方法将提供一个全面的 FANCM-BRCA 1合成致死相互作用机制的图片，并可能在FANCD 2中识别出一种新的 用于癌症治疗的合成致命靶点。 我

Project Summary/Abstract Breast and ovarian cancer are among the most common cancers in women worldwide.PARP inhibitors have shown potential for the treatment of BRCA-linked cancer, via a synthetic lethality mechanism that exploits the HR defect. However, tumors often develop resistance to these and other drugs. Therefore, there is a pressing need to find new, targeted treatments for BRCA-linked cancer. Genomic instability is a hallmark of cancer cells and a potential source of tumorigenesis. A major cause of genomic instability is replication fork stalling at sites of DNA damage or abnormal DNA structure. A limitation in the study of mammalian stalled fork repair has been a dearth of tools with which to analyze this process in molecular detail. The Scully lab solved this problem by adapting the Escherichia coli Tus/Ter replication fork barrier (RFB) to induce site-specific replication fork stalling on a mammalian chromosome. Tandem duplications (TDs) in primary cells lacking BRCA1 are induced specifically by a Tus/Ter block but not by a conventional double strand break (DSB), indicating specificity for the stalled fork response. Intriguingly, breast and ovarian cancers lacking BRCA1 similarly acquire large numbers of small (~10 kb) TDs, which we have termed “Group 1” TD. Thus, the Tus/Ter system recapitulates the BRCA1-specific regulation of Group 1 TD formation observed in human breast and ovarian cancer. I found that the stalled fork motor protein—FANCM (product of the Fanconi anemia [FA] group M gene) acts synergistically with BRCA1 to suppress Tus/Ter-induced TDs. Further, I discovered a novel synthetic lethal interaction between Brca1 and Fancm loss in mouse embryonic stem (ES) cells and in breast and ovarian cancer cells. These findings suggest that FANCM may be a promising therapeutic target in BRCA1-linked breast and ovarian cancer. My goals in this proposal are to delineate the novel FANCM-BRCA1 synthetic lethal interaction in cancer cells and to determine the mechanism of synthetic lethality (Aim1). Further, I will explore the chromatin environment and protein dynamics at the stalled fork and will study how alterations in these processes contribute to the FANCM-BRCA1 synthetic lethal interaction (Aim2). I observe an epistatic role of Fancm and its downstream target Fancd2 at Tus/Ter in promoting error free repair and suppressing error-prone repair.This critical role of Fancm and Fancd2 in repair pathway choice at stalled forks raises the possibility that they might share similar genetic interactions with Brca1. will identify how individual domains of FANCD2 function in repair pathway choice at stalled forks and their genetic interaction with Brca1 (Aim 3). This holistic approach will provide a full picture of the mechanism of FANCM-BRCA1 synthetic lethal interactions and might identify in FANCD2 a new synthetic lethal target for cancer therapy. I