Regulation of mitochondrial redox homeostasis and signaling in metastatic ovarian cancer

晚期卵巢癌的特点是患者存活率低，并有显著的转移扩散。 腹膜腔。在跨体腔体传播期间，细胞必须适应以独立于锚定生存并应对 与基质脱离和腹水的恶劣环境相关的压力。初步调查结果 证明卵巢癌细胞在锚定-独立过程中的一个重要适应是上调。 两种线粒体蛋白--超氧化物歧化酶2(Sod2)及其调节因子--代谢和 氧化还原敏感脱乙酰酶SIRT3。此外，这些蛋白质是不依赖于锚定的细胞所必需的。 活体内存活和跨体腔体转移。除了Sod2的S作为线粒体超氧化物歧化的作用 清道夫，机械学数据显示，Sod2将癌细胞的氧化还原图景转移到更高的氢 过氧化氢(H_2O_2)稳态。Sod2作为过氧化氢调节剂的这种新的非正则功能导致了 线粒体氧化还原信号，如磷酸酶的氧化和失活所证明的，并增强 AKT信令。初步数据表明，SIRT3是Sod2在锚定过程中的重要调节因子。 独立性，这表明SIRT3在卵巢癌扩散过程中具有促进生存的新作用。因此， 该提案将检验线粒体氧化还原信号是生存的重要调节因素这一假设 对基质脱离的适应，以及两个关键的线粒体蛋白SIRT3和Sod2，是 锚定非依赖性线粒体氧化还原信号的启动和调节所必需的。这将是 使用细胞培养模型、患者腹水来源的细胞、体内小鼠异种移植的组合来解决 模型，以及监测氧化剂和氧化还原信号的分子、生化和成像技术。两者都使用 无偏见的筛选和有针对性的方法目标1包括机制研究，以描绘SIRT3/Sod2- 受调控的线粒体过氧化氢信号驱动锚定非依赖生存。在目标2中， SIRT3的活性和转录调控将阐明SIRT3如何作为基质的传感器 在与锚定-独立性相关的代谢变化的背景下的脱离。在原则证明中 研究目的3针对Sod2-High肿瘤细胞的脆弱性将采取两种基于开发的方法 它们对过氧化氢产生剂和Akt抑制的敏感性。确定线粒体氧化还原信号是一种 卵巢癌不依赖锚定的生存和转移的必要适应对我们长期的 针对卵巢癌新疗法的关键转移适应的长期目标。

Late stage ovarian cancer is marked by poor patient survival and significant metastatic spread throughout the peritoneal cavity. During transcoelomic spread cells must adapt to survive anchorage-independence and to cope with stress associated with matrix detachment and the hostile environment of the ascites. Preliminary findings demonstrate that an important ovarian cancer cell adaptation during anchorage-independence is the up- regulation of two mitochondrial proteins, superoxide dismutase 2 (Sod2), and its regulator, the metabolic and redox sensing deacetylase SIRT3. Moreover, these proteins are necessary for anchorage-independent cell survival and transcoelomic metastasis in vivo. In addition to Sod2’s role as a mitochondrial superoxide scavenger, mechanistic data show that Sod2 shifts the redox landscape of cancer cells to a higher hydrogen peroxide (H2O2) steady-state. This novel non-canonical function of Sod2 as a H2O2 regulator results in mitochondrial redox signaling, as demonstrated by oxidation and inactivation of phosphatases, and enhanced Akt signaling. Preliminary data demonstrate that SIRT3 is an important regulator of Sod2 during anchorage- independence, which points to a novel pro-survival role for SIRT3 during ovarian cancer spread. Thus, the proposal will test the hypothesize that mitochondrial redox signaling is an important regulator of survival adaptations in response to matrix detachment, and that two key mitochondrial proteins, SIRT3 and Sod2, are required for the initiation and regulation of mitochondrial redox signaling in anchorage-independence. This will be addressed using a combination of cell culture models, patient ascites-derived cells, in vivo mouse xenograft models, and molecular, biochemical and imaging techniques to monitor oxidants and redox signaling. Using both unbiased screens and targeted approaches Aim 1 consists of mechanistic studies to delineate how SIRT3/Sod2- regulated mitochondrial H2O2-signaling drives anchorage-independent survival. In Aim 2 the mechanisms of SIRT3 activity and transcriptional regulation will be elucidated how SIRT3 acts as the sensor of matrix detachment in the context of metabolic changes associated with anchorage-independence. In proof-of-principle studies of Aim 3 the vulnerability of Sod2-high tumor cells will be targeted with two approaches based exploiting their sensitivity to H2O2 generating agents and Akt inhibition. Establishing that mitochondrial redox signaling is a necessary adaptation for ovarian cancer anchorage-independent survival and metastasis is crucial in our long- term goal of targeting key metastatic adaptations for novel therapies against ovarian cancer.