Tumor cells adapt their metabolism to meet the energetic and anabolic requirements of high proliferation and invasiveness. The metabolic addiction has motivated the development of therapies directed at individual biochemical nodes. However, currently there are few possibilities to target multiple enzymes in tumors simultaneously. Flavin-containing enzymes, ca. 100 proteins in humans, execute key biotransformations in mammalian cells. To expose metabolic addiction, we inactivated a substantial fraction of the flavoproteome in melanoma cells by restricting the supply of the FMN and FAD precursor riboflavin, the vitamin B2. Vitamin B2 deficiency affected stability of many polypeptides and thus resembled the chaperone HSP90 inhibition, the paradigmatic multiple-target approach. In support of this analogy, flavin-depleted proteins increasingly associated with a number of proteostasis network components, as identified by the mass spectrometry analysis of the FAD-free NQO1 aggregates. Proteome-wide analysis of the riboflavin-starved cells revealed a profound inactivation of the mevalonate pathway of cholesterol synthesis, which underlines the manifold cellular vulnerability created by the flavoproteome inactivation. Cell cycle-arrested tumor cells became highly sensitive to alkylating chemotherapy. Our data suggest that the flavoproteome is well suited to design synthetic lethality protocols combining proteostasis manipulation and metabolic reprogramming.

肿瘤细胞调整其代谢以满足高增殖和侵袭性的能量和合成代谢需求。代谢成瘾推动了针对个体生化节点的疗法的发展。然而，目前几乎没有可能同时靶向肿瘤中的多种酶。含黄素的酶，约。人类的 100 种蛋白质，在哺乳动物细胞中执行关键的生物转化。为了揭示代谢成瘾，我们通过限制 FMN 和 FAD 前体核黄素（维生素 B2）的供应，使黑色素瘤细胞中的大部分黄素蛋白组失活。维生素 B2 缺乏会影响许多多肽的稳定性，因此类似于分子伴侣 HSP90 抑制，即典型的多靶点方法。为了支持这个比喻，通过对无 FAD 的 NQO1 聚集体的质谱分析发现，黄素耗尽的蛋白质越来越多地与许多蛋白质稳态网络组件相关联。对核黄素饥饿细胞的全蛋白质组分析揭示了胆固醇合成的甲羟戊酸途径的严重失活，这突显了黄素蛋白质组失活造成的多种细胞脆弱性。细胞周期停滞的肿瘤细胞对烷化化疗高度敏感。我们的数据表明，flavoproteome 非常适合设计结合蛋白质稳态操作和代谢重编程的合成致死方案。对核黄素饥饿细胞的全蛋白质组分析揭示了胆固醇合成的甲羟戊酸途径的严重失活，这突显了黄素蛋白质组失活造成的多种细胞脆弱性。细胞周期停滞的肿瘤细胞对烷化化疗高度敏感。我们的数据表明，flavoproteome 非常适合设计结合蛋白质稳态操作和代谢重编程的合成致死方案。对核黄素饥饿细胞的全蛋白质组分析揭示了胆固醇合成的甲羟戊酸途径的严重失活，这突显了黄素蛋白质组失活造成的多种细胞脆弱性。细胞周期停滞的肿瘤细胞对烷化化疗高度敏感。我们的数据表明，flavoproteome 非常适合设计结合蛋白质稳态操作和代谢重编程的合成致死方案。