Targeting Metabolic Liabilities in Cancer

摘要/摘要 在转化的细胞中，积累生物量的需求需要实质性的代谢途径改变。 了解这种代谢变化将有助于识别可用于癌症的易感性。 心理治疗。在以前的工作中，我们发现高氧应激是驱动代谢途径的一种相当大的力量 乳腺癌中的依赖性。事实上，在高氧和低氧情况下，最不同需要的酶 环境，NFS1，是乳腺癌转移到肺部所必需的。此外，NFS1还存在于扩增的 肺腺癌中的阳性选择区域。因此，根据先前的工作，我们得出结论，高 肺的氧环境是早期乳房转移和肺癌的关键代谢因素 在一定程度上通过NFS1进行独特的适应。我们的工作是第一次描述这一关键途径在癌症中的作用。 这项拨款的目的是从机械上了解NFS1的要求，重点是基本的- 比如乳腺癌(BLBC)。NFS1是铁-硫簇(ISC)生物合成中的关键酶，是必需的 人类体内48种蛋白质中的辅因子。我们发现BLBC细胞系比鲁米那细胞系更敏感。 与抑制NFS1有关的线路。我们建议确定这一观察结果的机械基础，并 将我们的发现扩展到其他癌症亚型。我们将在一组乳房中抑制含有ISC的蛋白质 并验证在BLBC中哪些是不同需要的。验证的目标将在 基于异种移植的乳腺癌和转移模型，以评估它们对这些过程的影响。 许多含有ISC的基因参与了基因组完整性的维持。我们的前期工作 揭示了NFS1抑制导致双链DNA断裂的形成。这些观察结果导致了 美国将抑制POL，一种关键的基因组完整性酶。有趣的是，对杆子的压制也阻碍了 对BLBC细胞系的增殖和双链断裂的诱导作用远强于腔细胞系。之前的工作已经完成 提示BLBC在DNA修复方面存在缺陷，可能使其对治疗敏感。因此，我们将 抑制极点并评估对DNA复制、原点激发、复制分叉失速和重新启动的影响， 以及修复损坏的复制叉子。这些实验将有助于我们从根本上 了解BLBC对抑制DNA复制和诱导DNA损伤的敏感性。 最后，抑制NFS1通过一种非凋亡性的细胞死亡形式使细胞对氧化损伤敏感 称为铁性下垂。我们的发现导致了一种有趣的可能性，即铁饥饿反应的激活 在铁充足的条件下，从而诱使癌细胞摄取过量的铁，将使它们高度 容易受到进一步的氧化应激，并因铁性下垂而死亡。通过机械地理解如何最好地 激活NFS1下游的缺铁反应，我们预计我们将获得 诱导对氧化剂的敏感性增加，而不必针对通常细胞必需的途径。

Summary/Abstract In transformed cells the demand to accumulate biomass requires substantial metabolic pathway alteration. Understanding this altered metabolism will enable identification of liabilities that can be exploited for cancer therapy. In prior work, we found that hyperoxic stress is a considerable force driving metabolic pathway dependence in breast cancer. Indeed, the enzyme most differentially required in high versus low oxygen environments, NFS1, is required for breast cancer metastasis to the lung. Moreover, NFS1 lies in an amplified region under positive selection in lung adenocarcinoma. Therefore, from prior work we conclude that the high oxygen environment of the lung is a key metabolic factor to which incipient breast metastases and lung tumors uniquely adapt, in part, via NFS1. Ours is the first work to describe a role for this critical pathway in cancer. The purpose of this grant is to gain mechanistic understanding of the NFS1 requirement, focusing on basal- like breast cancer (BLBC). NFS1 is a key enzyme in the biosynthesis of iron-sulfur clusters (ISC), essential cofactors in 48 proteins in humans. We found that BLBC cell lines are strikingly more sensitive than luminal lines to suppression of NFS1. We propose to identify the mechanistic underpinnings of this observation, and extend our findings to other cancer subtypes. We will suppress ISC containing proteins in a panel of breast cancer cell lines and verify which are differentially required in BLBC. Validated targets will be inhibited in xenograft-based models of breast cancer and metastasis to assess their impact on these processes. Many ISC containing genes are involved in the maintenance of genomic integrity. Our preliminary work reveals that NFS1 suppression results in the formation of double strand DNA breaks. These observations led us to suppress POLE, a key genomic integrity enzyme. Interestingly, suppression of POLE also blocks proliferation and induces double strand breaks in BLBC cell lines far more than luminal lines. Prior work has indicated that BLBC has defects in aspects of DNA repair that may sensitize them to therapy. Therefore we will suppress POLE and assess the impact on DNA replication, origin firing, replication fork stalling and restarting, and the repair of damaged replication forks. These experiments will contribute to our fundamental understanding of the sensitivity of BLBC to inhibition of DNA replication and induction of DNA damage. Finally, NFS1 suppression sensitizes cells to oxidative damage via a non-apoptotic form of cell death termed ferroptosis. Our findings lead to the intriguing possibility that activation of the iron-starvation response in iron-replete conditions, thereby tricking cancer cells into taking up excess iron, will render them highly susceptible to further oxidative stress and death by ferroptosis. By mechanistically understanding how best to activate the iron-starvation response downstream of NFS1, we anticipate that we will gain the benefit of inducing increased sensitivity to oxidants without having to target a generally cell-essential pathway.