PDF(Pubmed)
Abstract：
Genetic mutations and chronic inflammation of the colon contribute to the development of colorectal cancer (CRC). Using a murine model of inflammation-induced colon tumorigenesis, we determined how genetic mutations alter colon tumor cell differentiation. Inflammation induced by enterotoxigenic Bacteroides fragilis (ETBF) colonization of multiple intestinal neoplasia (MinApcΔ716/+) mice triggers loss of heterozygosity of Apc causing colon tumor formation. Here, we report that the addition of BRAFV600E mutation (BRAFF-V600ELgr5tm1(Cre/ERT2)CleMinApcΔ716/+, BLM) or knocking out Msh2 (Msh2LoxP/LoxPVil1-creMinApcΔ716/+, MSH2KO) in the Min model altered colon tumor differentiation. Using single-cell RNA sequencing, we uncovered the differences between BLM, Min, and MSH2KO tumors at a single-cell resolution. BLM tumors showed an increase in differentiated tumor epithelial cell lineages and a reduction in the tumor stem cell population. Interestingly, the tumor stem cell population of BLM tumors had revival colon stem cell characteristics with low WNT signaling and an increase in RevCSC marker gene expression. In contrast, MSH2KO tumors were characterized by an increased tumor stem cell population that had higher WNT signaling activity compared to Min tumors. Furthermore, overall BLM tumors had higher expression of transcription factors that drive differentiation, such as Cdx2, than Min tumors. Using RNA velocity, we identified additional potential regulators of BLM tumor differentiation such as NDRG1. The role of CDX2 and NDRG1 as putative regulators for BLM tumor cell differentiation was verified using organoids derived from BLM tumors. Our results demonstrate the critical connections between genetic mutations and cell differentiation in inflammation-induced colon tumorigenesis. Understanding such roles will deepen our understanding of inflammation-associated colon cancer.
摘要：
基因突变和结肠的慢性炎症有助于结直肠癌（CRC）的发展。使用炎症诱导的结肠肿瘤发生的小鼠模型，我们确定了基因突变如何改变结肠肿瘤细胞分化.由肠产毒性脆弱拟杆菌（ETBF）定植的多发性肠瘤形成（MinApcΔ716/）小鼠引起的炎症引发Apc杂合性丧失，导致结肠肿瘤形成。这里,我们报道了添加BRAFV600E突变（BRAFF-V600ELgr5tm1（Cre/ERT2）CleMinApcΔ716/+，BLM)或敲除Msh2(Msh2LoxP/LoxPVil1-creMinApcΔ716/+,Min模型中的MSH2KO）改变了结肠肿瘤分化。使用单细胞RNA测序，我们发现了BLM之间的差异，Min,和MSH2KO肿瘤在单细胞分辨率。BLM肿瘤显示分化的肿瘤上皮细胞谱系增加，肿瘤干细胞群减少。有趣的是,BLM肿瘤的肿瘤干细胞群具有复苏结肠干细胞特征,WNT信号传导低,RevCSC标记基因表达增加.相比之下,MSH2KO肿瘤的特征在于与Min肿瘤相比具有更高的WNT信号传导活性的肿瘤干细胞群增加。此外，整体BLM肿瘤有较高的转录因子表达驱动分化，如Cdx2，比Min肿瘤。利用RNA速度，我们确定了BLM肿瘤分化的其他潜在调节因子,如NDRG1.使用源自BLM肿瘤的类器官验证了CDX2和NDRG1作为BLM肿瘤细胞分化的推定调节剂的作用。我们的结果证明了在炎症诱导的结肠肿瘤发生中基因突变和细胞分化之间的关键联系。了解这些作用将加深我们对炎症相关结肠癌的理解。
