title: Lineage tracing reveals multipotent stem cells maintain human adenomas and the pattern of clonal expansion in tumor evolution.
abstract: 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.
authors.affiliation: Histopathology Laboratory, Cancer Research UK London Research Institute, London, WC2A 3LY, United Kingdom.
authors.forename: Adam
authors.initials: A
authors.lastname: Humphries
authors.forename: Biancastella
authors.initials: B
authors.lastname: Cereser
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Gay
authors.forename: Daniel S J
authors.initials: DS
authors.lastname: Miller
authors.forename: Bibek
authors.initials: B
authors.lastname: Das
authors.forename: Alice
authors.initials: A
authors.lastname: Gutteridge
authors.forename: George
authors.initials: G
authors.lastname: Elia
authors.forename: Emma
authors.initials: E
authors.lastname: Nye
authors.forename: Rosemary
authors.initials: R
authors.lastname: Jeffery
authors.forename: Richard
authors.initials: R
authors.lastname: Poulsom
authors.forename: Marco R
authors.initials: MR
authors.lastname: Novelli
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodriguez-Justo
authors.forename: Stuart A C
authors.initials: SA
authors.lastname: McDonald
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Wright
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Graham
mesh_terms: D000236:Adenoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics*; D002999:Clone Cells / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004272:DNA, Mitochondrial / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D044127:Epigenesis, Genetic; D006801:Humans; D008954:Models, Biological; D039902:Multipotent Stem Cells / Q000378:metabolism / Q000473:pathology*; D009154:Mutation; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology*
chemical_list: D004272:DNA, Mitochondrial; D004273:DNA, Neoplasm
keywords: cancer stem cells; intestinal adenomas; intratumor heterogeneity; tumor growth; tumor life-history