α-Ketoglutarate attenuates Wnt signaling and drives differentiation in colorectal cancer [exome-seq]

Genetic-driven deregulation of the Wnt pathway is crucial but not sufficient for colorectal cancer (CRC) tumourigenesis. Here, we show that environmental glutamine restriction further augments Wnt signaling in APC mutant intestinal organoids to promote stemness and leads to adenocarcinoma formation in vivo via decreasing intracellular alpha-ketoglutarate (aKG) levels. aKG supplementation is sufficient to rescue low-glutamine induced stemness and Wnt hyperactivation. Mechanistically, we found that aKG promotes hypomethylation of DNA and histone H3K4me3, leading to an upregulation of differentiation-associated genes and downregulation of Wnt target genes, respectively. Using CRC patient-derived organoids and several in vivo CRC tumour models, we show that aKG supplementation suppresses Wnt signaling and promotes cellular differentiation, thereby significantly restricting tumour growth and extending survival. Together, our results reveal how the low glutamine metabolic microenvironment impacts Wnt signaling and identify aKG as a potent antineoplastic metabolite for potential differentiation therapy for CRC patients. 2 samples are analyzed for DNA variation using Exome Seq (control sample and low glutamine treated sample)

Wnt通路的遗传驱动失调在结直肠癌（colorectal cancer, CRC）肿瘤发生过程中至关重要，但并非充分条件。本研究表明，环境谷氨酰胺限制可进一步增强APC突变肠道类器官中的Wnt信号通路活性，增强细胞干性，并通过降低细胞内α-酮戊二酸（alpha-ketoglutarate, aKG）水平，在体内诱导腺癌形成。补充aKG即可逆转低谷氨酰胺诱导的干细胞干性增强与Wnt通路过度激活。机制研究显示，aKG可促进DNA与组蛋白H3K4me3的低甲基化，分别上调分化相关基因的表达，并下调Wnt通路靶基因的转录水平。本研究利用结直肠癌患者来源类器官与多种体内CRC肿瘤模型验证发现，补充aKG可抑制Wnt通路活性并促进细胞分化，从而显著限制肿瘤生长并延长模型动物生存期。综上，本研究揭示了低谷氨酰胺代谢微环境对Wnt通路信号的调控机制，并确认aKG可作为一种强效抗肿瘤代谢物，有望用于结直肠癌患者的分化治疗。本研究通过外显子测序（Exome Seq）对2份样本进行DNA变异分析，分别为对照组样本与低谷氨酰胺处理组样本。