α-Ketoglutarate attenuates Wnt signaling and drives differentiation in colorectal cancer [RNA-seq II]. α-Ketoglutarate attenuates Wnt signaling and drives differentiation in colorectal cancer [RNA-seq II]

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. Overall design: 6 samples are analyzed for RNA sequencing (3 biological replicates for control samples and 3 biological replicates for DM-aKG treated samples)

Wnt通路的遗传驱动失调对于结直肠癌（colorectal cancer, CRC）的肿瘤发生至关重要，但并非其发生的充分条件。本研究发现，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，促进干细胞干性，并通过降低细胞内α-酮戊二酸（alpha-ketoglutarate, aKG）水平在体内诱发腺癌形成。补充aKG足以挽救低谷氨酰胺诱导的干细胞干性及Wnt通路过度激活。从机制层面来看，本研究发现aKG可促进DNA及组蛋白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。利用CRC患者来源的类器官及多种体内CRC肿瘤模型，本研究证实补充aKG可抑制Wnt信号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如何影响Wnt信号通路，并确定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。实验整体设计：共对6份样本进行RNA测序（对照组与DM-aKG处理组各3份生物学重复样本）。