Cancer cells are reprogrammed to consume large amounts of glucose to support anabolic biosynthetic pathways. However, blood perfusion and consequently the supply with glucose are frequently inadequate in solid cancers. PEPCK-M (PCK2), the mitochondrial isoform of phosphoenolpyruvate carboxykinase (PEPCK), has been shown by us and others to be functionally expressed and to mediate gluconeogenesis, the reverse pathway of glycolysis, in different cancer cells. Serine and ribose synthesis have been identified as downstream pathways fed by PEPCK in cancer cells. Here, we report that PEPCK-M–dependent glycerol phosphate formation from noncarbohydrate precursors (glyceroneogenesis) occurs in starved lung cancer cells and supports de novo glycerophospholipid synthesis. Using stable isotope-labeled glutamine and lactate, we show that PEPCK-M generates phosphoenolpyruvate and 3-phosphoglycerate, which are at least partially converted to glycerol phosphate and incorporated into glycerophospholipids (GPL) under glucose and serum starvation. This pathway is required to maintain levels of GPL, especially phosphatidylethanolamine (PE), as shown by stable shRNA-mediated silencing of PEPCK-M in H23 lung cancer cells. PEPCK-M shRNA led to reduced colony formation after starvation, and the effect was partially reversed by the addition of dioleyl-PE. Furthermore, PEPCK-M silencing abrogated cancer growth in a lung cancer cell xenograft model. In conclusion, glycerol phosphate formation for de novo GPL synthesis via glyceroneogenesis is a newly characterized anabolic pathway in cancer cells mediated by PEPCK-M under conditions of severe nutrient deprivation.

重新编程癌细胞以消耗大量葡萄糖以支持合成代谢生物合成途径。然而，在实体癌中，血液灌注以及因此的葡萄糖供应经常不足。PEPCK-M（PCK2），磷酸烯醇丙酮酸羧化激酶（PEPCK）的线粒体同工型，已被我们和其他人证明在不同癌细胞中功能性表达并介导糖异生的逆向途径，即糖异生。丝氨酸和核糖的合成已被确定为癌细胞中PEPCK提供的下游途径。在这里，我们报道了由非碳水化合物前体形成的PEPCK-M依赖性甘油磷酸酯（甘油生成）发生在饥饿的肺癌细胞中，并支持从头合成甘油磷脂。使用稳定的同位素标记的谷氨酰胺和乳酸，我们显示PEPCK-M生成磷酸烯醇丙酮酸和3-磷酸甘油酸酯，它们至少部分转化为甘油磷酸酯，并在葡萄糖和血清饥饿的情况下掺入甘油磷脂（GPL）中。该途径是维持GPL尤其是磷脂酰乙醇胺（PE）的水平所必需的，如在H23肺癌细胞中由shRNA介导的PEPCK-M的稳定shRNA沉默所示。PEPCK-M shRNA导致饥饿后集落形成减少，并且通过添加二油基-PE可以部分逆转该作用。此外，PEPCK-M沉默消除了肺癌细胞异种移植模型中的癌症生长。总之，在严重营养物质缺乏的情况下，由PEPCK-M介导的癌细胞中通过甘油生成从头合成GPL的磷酸甘油形成是新近表征的合成代谢途径。通过添加二油基-PE可以部分逆转该效果。此外，PEPCK-M沉默消除了肺癌细胞异种移植模型中的癌症生长。总之，在严重营养物质缺乏的情况下，由PEPCK-M介导的癌细胞中通过甘油生成从头合成GPL的磷酸甘油形成是新近表征的合成代谢途径。通过添加二油基-PE可以部分逆转该效果。此外，PEPCK-M沉默消除了肺癌细胞异种移植模型中的癌症生长。总之，在严重营养物质缺乏的情况下，由PEPCK-M介导的癌细胞中通过甘油生成从头合成GPL的磷酸甘油形成是新近表征的合成代谢途径。