title: Alkaline phosphatase-positive colony formation is a sensitive, specific, and quantitative indicator of undifferentiated human embryonic stem cells.
abstract: Human embryonic stem cells (hESCs) can be maintained in vitro as immortal pluripotent cells but remain responsive to many differentiation-inducing signals. Investigation of the initial critical events involved in differentiation induction would be greatly facilitated if a specific, robust, and quantitative assay for pluripotent hESCs with self-renewal potential were available. Here we describe the results of a series of experiments to determine whether the formation of adherent alkaline phosphatase-positive (AP(+)) colonies under conditions optimized for propagating undifferentiated hESCs would meet this need. The findings can be summarized as follows. (a) Most colonies obtained under these conditions consist of >or=30 AP(+) cells that coexpress OCT4, NANOG, SSEA3, SSEA4, TRA-1-60, and TRA-1-81. (b) Most such colonies are derived from SSEA3(+) cells. (c) Primary colonies contain cells that produce secondary colonies of the same composition, including cells that initiate multilineage differentiation in embryoid bodies (EBs). (d) Colony formation is independent of plating density or the colony-forming cell (CFC) content of the test population over a wide range of cell concentrations. (e) CFC frequencies decrease when differentiation is induced by exposure either to retinoic acid or to conditions that stimulate EB formation. Interestingly, this loss of AP(+) clonogenic potential also occurs more rapidly than the loss of SSEA3 or OCT4 expression. The CFC assay thus provides a simple, reliable, broadly applicable, and highly specific functional assay for quantifying undifferentiated hESCs with self-renewal potential. Its use under standardized assay conditions should enhance future elucidation of the mechanisms that regulate hESC propagation and their early differentiation.
authors.affiliation: Terry Fox Laboratory, 675 West 10th Avenue, Vancouver, British Columbia, Canada V5Z 1L3. moconnor@bccrc.ca
authors.forename: Michael D
authors.initials: MD
authors.lastname: O'Connor
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Kardel
authors.forename: Ioulia
authors.initials: I
authors.lastname: Iosfina
authors.forename: David
authors.initials: D
authors.lastname: Youssef
authors.forename: Min
authors.initials: M
authors.lastname: Lu
authors.forename: Michael M
authors.initials: MM
authors.lastname: Li
authors.forename: Suzanne
authors.initials: S
authors.lastname: Vercauteren
authors.forename: Andras
authors.initials: A
authors.lastname: Nagy
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Eaves
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000378:metabolism; D002452:Cell Count; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D002999:Clone Cells; D003114:Colony-Forming Units Assay; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000201:enzymology*; D006028:Glycosphingolipids / Q000378:metabolism; D006801:Humans; D051379:Mice; D010641:Phenotype; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000201:enzymology; D012680:Sensitivity and Specificity; D055746:Stage-Specific Embryonic Antigens
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D006028:Glycosphingolipids; D055746:Stage-Specific Embryonic Antigens; C052924:stage-specific embryonic antigen-3; D000469:Alkaline Phosphatase