a-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在结直肠癌（colorectal cancer, CRC）肿瘤发生中至关重要，但并非充分的驱动因素。本研究发现，环境谷氨酰胺限制可通过降低细胞内α-酮戊二酸（alpha-ketoglutarate, aKG）水平，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，并在体内诱导腺癌形成。补充aKG即可完全逆转低谷氨酰胺诱导的干细胞干性增强及Wnt通路过度激活。机制研究显示，aKG可促进DNA及组蛋白H3K4me3的去甲基化，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。借助结直肠癌患者来源类器官及多种体内结直肠癌肿瘤模型，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，进而显著限制肿瘤生长并延长模型动物的生存期。综上，本研究揭示了低谷氨酰胺代谢微环境调控Wnt信号通路的具体机制，并确定aKG为一种强效抗肿瘤代谢物，有望用于结直肠癌患者的分化靶向治疗。实验整体设计：本研究共对6份样本进行RNA测序分析，其中对照组与DM-aKG处理组各设3次生物学重复。