Role of succinate dehydrogenase in ovarian cancer metabolism

化疗耐药的卵巢癌在约85%的患者中复发，并导致与癌症相关的高比率 死亡率。细胞代谢向厌氧糖酵解的重新编程(沃堡效应)是一种 化疗耐药的重要机制。针对人体独特代谢状态的精准医学 癌症有望提高卵巢癌治疗的疗效并减少化疗 抵抗。从我们的患者来源的卵巢肿瘤的代谢途径的综合分析 在癌症基因组图谱(TCGA)数据中，我们发现一种关键的线粒体酶琥珀酸 脱氢酶(SDHA)在19%的卵巢癌患者中显著上调，并与 显著提高了患者的存活率。我们的初步研究表明，升高的SDHA增加了 线粒体丙酮酸载体1(MPC1)蛋白表达，增加丙酮酸向线粒体的输入 从而逆转华宝效应，抑制细胞增殖。另外，我们的初步数据 表明SDHA升高有助于氧化还原系统的失衡，从而可能使卵巢癌细胞增敏 到化疗和/或产生活性氧簇(ROS)的药物。这项研究的总体目标是 是确定升高的SDHA改变卵巢肿瘤生物学的机制，以充分利用 可用药的代谢脆弱性，如对化疗和/或产生ROS的敏感性增加 提高患者存活率的药物。在目标1中，我们将确定提升SDHA的机制 重新编程细胞代谢以调节卵巢癌细胞的增殖。我们将过度表达或击倒 卵巢癌细胞系中SDHA的代谢和功能特征，包括 海马XF的糖酵解、耗氧量和丙酮酸向线粒体转运的评价 技术、质谱学和代谢示踪剂分析。我们将探索独立的角色 SDHA、SDHA底物(琥珀酸、富马酸)或MPC1在细胞代谢和再编程中的升高 细胞增殖。在目标2中，我们将确定升高的SDHA是否通过损害细胞氧化还原调节而增加 卵巢肿瘤对化疗(顺铂/紫杉醇)和/或ROS生成剂(Elesclomol)的敏感性。我们 将通过以下方式测试SDHA在增加线粒体依赖的呼吸和ROS产生方面的效果 进行呼吸测量分析。最后，我们将在体内测试SDHA扩增的卵巢肿瘤是否表现更好 使用选定患者来源的异种移植物(PDX)对化疗和/或elesclomol的反应。这个 该项目的直接贡献是探索SDHA在改变线粒体能量方面的新作用 新陈代谢通过抑制肿瘤生长和/或增加卵巢癌患者的生存 化疗杀灭肿瘤细胞的有效性。这项研究是迈向我们长期目标的关键一步， 开发精确调节卵巢癌特异性代谢的创新方法以提高患者的反应 为治疗和生存干杯。

Chemotherapy-resistant ovarian cancer recurs in ~85% of patients and contributes to high rates of cancer-related mortality. The reprograming of cellular metabolism towards anaerobic glycolysis (the Warburg effect) is an important mechanism of chemotherapy resistance. Precision medicine targeting the unique metabolic state of cancer holds great promise to improve the efficacy of ovarian cancer treatment and reduce chemotherapy resistance. From a comprehensive analysis of metabolic pathways in our patient-derived ovarian tumors and The Cancer Genome Atlas (TCGA) data, we discovered that a key mitochondrial enzyme, succinate dehydrogenase (SDHA), is significantly upregulated in 19% of ovarian cancer patients, and is associated with significantly improved patient survival. Our preliminary studies indicate that elevated SDHA increases mitochondrial pyruvate carrier 1 (MPC1) protein expression, which increases pyruvate import to mitochondrial leading to reversal of the Warburg effect and suppression of cell proliferation. In addition, our preliminary data shows that elevated SDHA contributes to imbalance of redox systems, which may sensitize ovarian cancer cells to chemotherapy and/or agents that generate reactive oxygen species (ROS). The overall goal of this study is to determine the mechanism by which elevated SDHA alters ovarian tumor biology to take full advantage of druggable metabolic vulnerabilities such as increased sensitivity to chemotherapy and/or ROS-generating agents to improve patient survival. In Aim 1, we will determine the mechanism by which elevated SDHA reprograms cellular metabolism to regulate ovarian cancer cell proliferation. We will overexpress or knockdown SDHA in ovarian cancer cell lines followed by metabolic and functional characterization of the cells including an evaluation of glycolysis, oxygen consumption and pyruvate transport into mitochondria by Seahorse XF Technology, mass spectrometry and metabolic tracer analyses. We will explore the independent roles of elevated SDHA, SDHA substrates (succinate, fumarate), or MPC1 in reprograming of cellular metabolism and cell proliferation. In Aim 2, we will determine if elevated SDHA, by impairing cellular redox regulation, increases ovarian tumor sensitivity to chemotherapy (cisplatin/paclitaxel) and/or a ROS-generating agent (elesclomol). We will test the effect of SDHA on increasing mitochondrial-dependent respiration and ROS generation by performing respirometry analyses. Finally, we will test in vivo if SDHA-amplified ovarian tumors show better responses to chemotherapy and/or elesclomol using selected patient-derived xenografts (PDXs). The immediate contribution of this project is to explore the novel role of SDHA in changing mitochondrial energy metabolism to improve ovarian cancer patient survival by suppressing of tumor growth and/or increasing the effectiveness of chemotherapy to kill tumor cells. This study is a critical step toward our long-term goal, to develop innovative ways to precisely modulate ovarian cancer-specific metabolism to improve patients’ response to therapy and survival.