Abstract：
Epithelial ovarian cancer (EOC) is highly lethal due to its unique metastatic characteristics. EOC spheroids enter a non-proliferative state, with hypoxic cores and reduced oncogenic signaling, all of which contribute to tumour dormancy during metastasis. We investigated the metabolomic states of EOC cells progressing through the three steps to metastasis. Metabolomes of adherent, spheroid, and re-adherent cells were validated by isotopic metabolic flux analysis and mitochondrial functional assays to identify metabolic pathways that were previously unknown to promote EOC metastasis. Although spheroids were thought to exist in a dormant state, metabolomic analysis revealed an unexpected upregulation of energy production pathways in spheroids, accompanied by increased abundance of tricarboxylic acid (TCA) cycle and electron transport chain proteins. Tracing of 13C-labelled glucose and glutamine showed increased pyruvate carboxylation and decreased glutamine anaplerosis in spheroids. Increased reductive carboxylation suggests spheroids adjust redox homeostasis by shuttling cytosolic NADPH into mitochondria via isocitrate dehydrogenase. Indeed, we observed spheroids have increased respiratory capacity and mitochondrial ATP production. Relative to adherent cells, spheroids reduced serine consumption and metabolism, processes which were reversed upon spheroid re-adherence. The data reveal a distinct metabolism in EOC spheroids that enhances energy production by the mitochondria while maintaining a dormant state with respect to growth and proliferation. The findings advance our understanding of EOC metastasis and identify the TCA cycle and mitochondrional activity as novel targets to disrupt EOC metastasis, providing new approaches to treat advanced disease.
摘要：
上皮性卵巢癌（EOC）由于其独特的转移特征而具有高度致命性。EOC球体进入非增殖状态,缺氧核心和减少的致癌信号，所有这些都有助于转移过程中的肿瘤休眠。我们研究了EOC细胞通过三个步骤进展到转移的代谢组学状态。粘附的代谢体，球体,和再贴壁细胞通过同位素代谢通量分析和线粒体功能分析进行验证,以鉴定以前未知的促进EOC转移的代谢途径.虽然球体被认为是以休眠状态存在,代谢组学分析揭示了球体中能量产生途径的意外上调，伴随着三羧酸（TCA）循环和电子传递链蛋白的丰度增加。对13C标记的葡萄糖和谷氨酰胺的追踪显示，球状体中丙酮酸羧化作用增加，谷氨酰胺回补作用减少。还原性羧化增加表明球状体通过将胞质NADPH通过异柠檬酸脱氢酶穿梭到线粒体中来调节氧化还原稳态。的确,我们观察到球体的呼吸能力和线粒体ATP产生增加。相对于贴壁细胞，球体减少了丝氨酸的消耗和代谢，球状体重新粘附后逆转的过程。数据揭示了EOC球状体中的独特代谢，可增强线粒体的能量产生，同时保持生长和增殖的休眠状态。这些发现促进了我们对EOC转移的理解，并将TCA周期和线粒体活性确定为破坏EOC转移的新靶标。提供治疗晚期疾病的新方法。
