Lineage tracing reveals multipotent stem cells maintain human adenomas and the pattern of clonal expansion in tumor evolution
Lineage tracing reveals multipotent stem cells maintain human adenomas and the pattern of clonal expansion in tumor evolution
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DOI：
10.1073/pnas.1220353110
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发表时间：
2013-07-02
影响因子：
11.1
通讯作者：
Graham, Trevor A.
中科院分区：
文献类型：
--
作者：
Humphries, Adam;Cereser, Biancastella;Graham, Trevor A.
结直肠癌的遗传和形态学发展是肿瘤发生的范例。然而，支持癌发生的克隆进化动力学仍然知之甚少。在这里，我们确定多潜能干细胞在人类结直肠腺瘤和使用甲基化模式的非表达基因的克隆进化的特点。从6个结肠腺瘤和增生性息肉的许多个人隐窝进行显微解剖和遗传病变的特点。通过组织化学染色和线粒体DNA测序鉴定细胞色素c氧化酶（CCO-）缺陷的克隆。克隆位置的地形图构建使用这些数据的组合。通过免疫荧光证实了克隆内的多谱系分化。通过亚硫酸氢盐克隆测序确定腺瘤性隐窝的甲基化模式;用数学模型比较甲基化模式多样性以推断克隆动力学。单个腺瘤性隐窝的mtDNA突变是克隆性的，并且含有粘液分泌细胞和神经内分泌细胞，表明隐窝含有多能干细胞。胞内甲基化模式与含有多个竞争干细胞的隐窝一致。腺瘤是表观遗传多样性的人群，这表明他们是相对有丝分裂年龄较大的人群。肿瘤内克隆的甲基化模式的多样性通常低于整个肿瘤。数学建模表明，最近的克隆扫描涵盖整个腺瘤没有发生。人类肿瘤内的腺瘤性隐窝含有活跃分裂的干细胞。腺瘤似乎是相对较老的有丝分裂人群，偶尔有新产生的亚克隆，是最近快速克隆扩张的结果。相对停滞和偶尔的快速亚克隆生长可能是结直肠肿瘤发生的特征。
The genetic and morphological development of colorectal cancer is a paradigm for tumorigenesis. However, the dynamics of clonal evolution underpinning carcinogenesis remain poorly understood. Here we identify multipotential stem cells within human colorectal adenomas and use methylation patterns of nonexpressed genes to characterize clonal evolution. Numerous individual crypts from six colonic adenomas and a hyperplastic polyp were microdissected and characterized for genetic lesions. Clones deficient in cytochrome c oxidase (CCO-) were identified by histochemical staining followed by mtDNA sequencing. Topographical maps of clone locations were constructed using a combination of these data. Multilineage differentiation within clones was demonstrated by immunofluorescence. Methylation patterns of adenomatous crypts were determined by clonal bisulphite sequencing; methylation pattern diversity was compared with a mathematical model to infer to clonal dynamics. Individual adenomatous crypts were clonal for mtDNA mutations and contained both mucin-secreting and neuroendocrine cells, demonstrating that the crypt contained a multipotent stem cell. The intracrypt methylation pattern was consistent with the crypts containing multiple competing stem cells. Adenomas were epigenetically diverse populations, suggesting that they were relatively mitotically old populations. Intratumor clones typically showed less diversity in methylation pattern than the tumor as a whole. Mathematical modeling suggested that recent clonal sweeps encompassing the whole adenoma had not occurred. Adenomatous crypts within human tumors contain actively dividing stem cells. Adenomas appeared to be relatively mitotically old populations, pocketed with occasional newly generated subclones that were the result of recent rapid clonal expansion. Relative stasis and occasional rapid subclone growth may characterize colorectal tumorigenesis.