title: Characterization of sphere-forming cells with stem-like properties from the small cell lung cancer cell line H446.
abstract: A relatively novel paradigm in tumor biology hypothesizes that cancer growth is driven by tumor cells with stem-like properties. However, direct proof of a population of stem cells in small cell lung cancer (SCLC) remains elusive. In this study, we enriched for stem-like cells from the SCLC cell line H446 by growing them as spheres in a defined serum-free medium. Sphere-derived cells have increased in vitro clonogenic and in vivo tumorigenic potentials as well as drug-resistant properties. After enrichment for stem-like cells, we used multiple candidate stem cell markers to examine the expression profile and found that the sphere-derived cells contained a higher proportion of cells expressing the stem cell surface markers uPAR and CD133 when compared with parental cells. To identify a selectable marker for the sphere-forming cells, we evaluated the sphere-forming abilities of uPAR(+) and uPAR(-) cells as well as the sphere-forming abilities of CD133(+) and CD133(-) cells. Both CD133(+) and CD133(-) cell fractions were capable of forming spheres, and no statistically significant difference was observed in the sphere-forming efficiency between these two populations. In contrast, cells derived from the uPAR(+) fraction were capable of forming spheres, whereas cells derived from the uPAR(-) fraction remained as single cells. Moreover, uPAR(+) cells efficiently formed transplantable tumors, whereas uPAR(-) cells were unable to initiate tumors when transplanted at equivalent cell numbers. In addition, uPAR(+) cells could differentiate into CD56(+)cells, CK(+) cells, and uPAR(-) cells. These data support the existence of a population of tumor sphere-forming cells with stem cell properties in the H446 SCLC cell line. Furthermore, the stem cell population may be enriched in cells expressing the uPAR cell surface marker.
authors.affiliation: Department of Pathology, Tianjin Medical University, Tianjin 300070, China. qiouxf@tijmu.edu.cn
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Qiu
authors.forename: Zhengyan
authors.initials: Z
authors.lastname: Wang
authors.forename: Yanlei
authors.initials: Y
authors.lastname: Li
authors.forename: Yajing
authors.initials: Y
authors.lastname: Miao
authors.forename: Yu
authors.initials: Y
authors.lastname: Ren
authors.forename: Yajing
authors.initials: Y
authors.lastname: Luan
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000276:immunology; D018288:Carcinoma, Small Cell / Q000276:immunology / Q000473:pathology*; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D008175:Lung Neoplasms / Q000276:immunology / Q000473:pathology*; D014411:Neoplastic Stem Cells / Q000276:immunology / Q000473:pathology*; D010455:Peptides / Q000276:immunology
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides