Cooperation of side population cells with CD133 to enrich cancer stem cells in a laryngeal cancer cell line

Abstract

Background The identification of cancer stem cells (CSCs) in laryngeal cancer remains a dilemma. Our previous studies identified CD133(+) subgroup and side population (SP) cells in the laryngeal cancer cell line, human epithelial type-2 (Hep-2). Although both cell types shared some tumor-initiating properties, they were heterogeneous. In this study, we further enriched CSCs from this cell line. Methods We divided the SP cells into CD133(+)SP and CD133(-)SP cells by combining SP and CD133, and compared CSC-associated properties between the 2 subgroups. Results SP cells contained CD133(+)SP and CD133(-)SP, and CD133(+)SP cells manifested preferential expression of self-renewal genes, higher capacity for proliferation, differentiation, and clone and spheroid formation, enhanced resistance to radiation and chemotherapy, and greater tumorigenicity compared with CD133(-)SP cells. Conclusion The CD133(+)SP subpopulation is enriched in CSCs compared with the CD133(-)SP subgroup, suggesting that the combination of SP and CD133 can further purify CSCs in the Hep-2 cell line. © 2013 Wiley Periodicals, Inc. Head Neck 36: 1279–1287, 2014