Targeting Iron-Sulfur Cluster Biosynthesis for the Treatment of Basal-Like Breast Cancer

项目总结/摘要 乳腺癌占美国妇女癌症相关死亡的第二位，尽管可以获得 改善治疗选择和增加筛查。一种特别具有攻击性的亚型， 这些死亡病例中不成比例的是基底样乳腺癌（BLBC）。这种亚型经常 复发并有转移的倾向此外，对于BLBC不存在定向疗法。因此，为了 改善这种亚型患者的预后，识别BLBC中的新漏洞， 允许设计和开发定向治疗。引人注目的是，我们发现BLBC细胞 细胞系，而不是管腔细胞系，表现出严重的敏感性，抑制铁硫簇（ISC） 生物合成，一种支持至少48种参与细胞过程的蛋白质功能的途径， 能量代谢、铁稳态和DNA复制和修复。此外，抑制NFS 1，一个关键， ISC生物合成途径中的酶，防止基底样乳腺癌转移到肺。因此 鉴定哪些下游含ISC蛋白驱动这种敏感性有望阐明途径 BLBC中的漏洞可能导致对这种预后不良的亚型进行靶向治疗 有限的治疗选择。本奖学金计划的工作将确定不同需要的ISC 在BLBC中含有蛋白质，然后将使用体外和异种移植模型验证它们，以研究 抑制蛋白质对肿瘤形成、生长和转移的影响。经验证的目标将 在相同的模型中测试与当前BLBC治疗的协同作用。初步数据显示， ISC生物合成抑制后的基因组不稳定性有助于在细胞中观察到的增殖缺陷。 BLBC细胞系。进一步的实验表明，DNA聚合酶ε（POLE），前导链， 复制聚合酶是这样一种差异需要的蛋白质。我们假设BLBC是高度 对POLE抑制敏感，因为这种肿瘤类型中的DNA修复缺陷使得POLE活性至关重要 基因组的完整性为了评估这一假设，互补和独立的方法，分析 DNA损伤信号传导途径，检查复制传播和起源放电，并从遗传学角度剖析 将使用POLE子单元的角色。这些方法将提供一个严格的特点的作用 POLE在BLBC DNA损伤修复途径中的作用。总的来说，我们拟议的工作将确定和 描述BLBC中ISC通路的脆弱性，从中可以开发新的靶向治疗。

Project Summary/Abstract Breast cancer accounts for the second most cancer-related deaths in U.S. women despite the availability of improved treatment options and increased screening. A particularly aggressive subtype that represents a disproportionate number of these mortality cases is basal-like breast cancer (BLBC). This subtype frequently relapses and has a propensity to metastasize. Moreover, no directed therapies exist for BLBC. Hence, to improve outcomes for patients with this subtype, the identification of novel vulnerabilities in BLBC that would allow for the design and development of directed treatments is required. Strikingly, we find that BLBC cell lines, but not luminal cell lines, exhibit a severe sensitivity to suppression of iron-sulfur cluster (ISC) biosynthesis, a pathway that supports the function of at least 48 proteins involved in cellular processes such as energy metabolism, iron homeostasis, and DNA replication and repair. Moreover, suppression of NFS1, a key enzyme in the ISC biosynthetic pathway, prevents basal-like breast cancer metastasis to the lung. Thus, the identification of which downstream ISC containing proteins drive this sensitivity promises to elucidate pathway vulnerabilities in BLBC that could potentially lead to a targeted therapy for this subtype with a poor prognosis and limited treatment options. The proposed work in this fellowship will identify differentially required ISC containing proteins in BLBC and then will validate them using in vitro and xenograft models to investigate the effects of suppressing the proteins on tumor formation, growth, and metastasis. Validated targets will then be tested in the same models for synergy with current BLBC treatments. Preliminary data suggests that induction of genomic instability upon ISC biosynthesis suppression contributes to the proliferation defects observed in BLBC cell lines. Further experiments demonstrate that DNA Polymerase ε (POLE), the leading strand replicative polymerase, is one such differentially required protein. We hypothesize that BLBC is highly sensitive to POLE suppression due to a DNA repair defect in this tumor type that renders POLE activity critical for genomic integrity. To evaluate this hypothesis, complementary and independent approaches that analyze DNA damage signaling pathways, examine replication propagation and origin firing, and genetically dissect the role of POLE subunits will be employed. These approaches will provide a stringent characterization of the role of POLE in DNA damage repair pathways in BLBC. Collectively, our proposed work will identify and characterize ISC pathway vulnerabilities in BLBC from which novel targeted therapies could be developed.