Weakened spindle checkpoint in vivo: a cause of aneuploidy and cancer in FA?

项目总结 Fanconi贫血(FA/BRCA)途径由至少17种维持基因组稳定的蛋白质组成 并预防癌症。任何FA基因的双等位种系破坏都会导致Fanconi贫血(FA)，一种遗传性 导致骨髓衰竭和罹患癌症风险高的疾病。FA/BRCA基因的体细胞突变发生在 自发性癌症。因此，FA/BRCA信号的中断会促进这两种遗传疾病的发生 综合症和普通人群。 FA肿瘤抑制因子网络控制着多个基因组管家检查点。除了……之外 FA蛋白在间期DNA复制/修复中的作用，FA途径控制有丝分裂， 包括纺锤体组装检查点(SAC)，这是一个调节染色体的肿瘤抑制网络 种族隔离。SAC受多种肿瘤抑制因子的调节，包括MAD2和SAC损伤 易患非整倍体和癌症。然而，丢失时导致SAC功能异常的机制 在很大程度上仍不清楚。此外，SAC功能障碍在大鼠体内的临床意义 FA相关肿瘤的发病机制需要在未来的治疗发展之前进行探索 针对FA缺陷细胞中被削弱的SAC的策略可以成为现实。 我们假设SAC功能障碍有助于体内非整倍体和癌症的发展 在FA信令丢失时。为了验证这一假设，我们建立了一个新的Fancc-/-；MAD2+/-小鼠模型， 其中MAD2杂合性进一步削弱了FA缺乏背景下的SAC功能。在目标1中，我们将 确定这些Fancc-/-；MAD2+/-小鼠是否容易患癌症。利用这些动物的细胞，我们将 采用微核试验评估SAC功能障碍在糖尿病发生发展中的相对作用 非整倍体与间期DNA损伤修复等其他已知因素的比较。此外，我们的目标是 分析FANCC缺失导致染色体错误分离的机制。 通过定义FANCC和其结合伙伴CDK1之间的关系来损害有丝分裂 中期向后期过渡的调节器(目标2)。这项建议将使我们更好地理解 在FA信号失活的背景下，SAC功能障碍作为基因组不稳定和肿瘤发生的驱动因素， 并最终促进以有丝分裂为中心的FA相关肿瘤治疗的发展。

PROJECT SUMMARY Fanconi anemia (FA/BRCA) pathway is comprised of at least 17 proteins that maintain genomic stability and prevent cancer. Bi-allelic germline disruption of any FA gene causes Fanconi anemia (FA), a genetic disorder causing bone marrow failure and high risk of cancer. Somatic mutations of FA/BRCA genes occur in spontaneous cancers. Thus, disruption of FA/BRCA signaling promotes malignancies in both inherited syndromes and the general population. The FA tumor suppressor network controls multiple genome-housekeeping checkpoints. In addition to the well-established roles of FA proteins in interphase DNA replication/repair, the FA pathway controls mitosis, including the spindle assembly checkpoint (SAC), a tumor suppressor network that regulates chromosome segregation. The SAC is regulated by several tumor suppressors, including MAD2, and SAC impairment predisposes to aneuploidy and cancer. However, the mechanisms causing abnormal SAC function upon loss of FA remain largely unknown. Furthermore, the in vivo clinical significance of SAC dysfunction in the pathogenesis of FA-associated cancers needs to be explored before the development of future therapeutic strategies targeting the weakened SAC in FA-deficient cells can become a reality. We hypothesize that SAC dysfunction contributes to the in vivo development of aneuploidy and cancer upon loss of FA signaling. To test this hypothesis, we have generated a novel Fancc-/-; Mad2+/- mouse model, in which Mad2 heterozygosity further weakens SAC function in the FA-deficient background. In Aim 1, we will determine whether these Fancc-/-; Mad2+/- mice are cancer-prone. Utilizing cells from these animals, we will employ a micronucleus test to assess the relative contribution of SAC dysfunction to the development of aneuploidy in comparison to other known factors such as interphase DNA damage repair. Additionally, we aim to dissect the mechanism by which loss of FANCC contributes to erroneous chromosome segregation and impaired mitosis by defining the relationship between FANCC and its binding partner CDK1, a well-known regulator of the metaphase-to-anaphase transition (Aim 2). This proposal will lead to a better understanding of SAC dysfunction as a driver of genomic instability and tumorigenesis in the context of FA signaling inactivation, and ultimately contribute to the development of mitotic-centered therapies for FA-associated tumors.