Characterization of sphere-forming cells with stem-like properties from the small cell lung cancer cell line H446

• Published in: Cancer letters 2012-10, Vol.323 (2), p.161-170
• Main Authors: Qiu, Xiaofei, Wang, Zhengyan, Li, Yanlei, Miao, Yajing, Ren, Yu, Luan, Yajing
• Format: Article
• Language: English
• Subjects: AC133 Antigen; Antigens, CD - immunology; Biomarkers; Cancer stem cells; Cancer therapies; Carcinoma, Small Cell - immunology; Carcinoma, Small Cell - pathology; Cell Line, Tumor; cell lines; Chemotherapy; Experiments; Flow Cytometry; Fluorescent Antibody Technique; Glycoproteins - immunology; Hematology, Oncology and Palliative Medicine; Humans; Lung cancer; lung neoplasms; Lung Neoplasms - immunology; Lung Neoplasms - pathology; Neoplastic Stem Cells - immunology; Neoplastic Stem Cells - pathology; Peptides - immunology; Population; Small cell lung cancer; Spheres; Stem cells; Studies; Tumor sphere; Tumors; uPAR
• ISSN: 0304-3835; 1872-7980
• DOI: 10.1016/j.canlet.2012.04.004

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.