Isolation and characterization of cancer stem cell-like sphere-forming cell subpopulation from the human nasopharyngeal cell line CNE-2 / 中国肿瘤临床

ABSTRACT

Objective: The present study aimed to isolate and characterize a cancer stem cell-like sphere-forming cell subpopula-tion. Methods: By using a spheroid culture stem cell-conditioned medium, we isolated a subgroup of cancer stem-like cells from naso-pharyngeal cancer cell lines. Chemotherapy resistance was analyzed by using methyl thiazolyl tetrazolium, and clone-forming capabili-ty was determined by using softer agar clone formation assay. Finally, we verified the expression of the stemness-specific gene andβ-catenin by using immunocytochemistry staining and RT-PCR. Results: The lower-differentiated nasopharyngeal cancer lines con-tained more sphere-forming cells, whereas sphere-forming cells were not observed in the high differentiated nasopharyngeal cancer line CNE-1. Compared with CNE-2, CNE-2S (sphere-forming cells derived from CNE-2) exhibited higher chemotherapy resistance and clone-forming ability. Interestingly, the stemness genes BMI-1, ABCG2, and ALDH1 exhibited higher expression in CNE-2S than in CNE-2. β-catenin, a vital transcription factor of the WNT pathway related to stem cells, exhibited higher expression in CNE-2s cellular nucleus and plasma than in CNE-2. Conclusion: We isolated a subgroup of stem-like nasopharyngeal cancer sphere-forming cells. This discovery paves the way for the development of therapeutic strategies aimed at eradicating tumorigenic subpopulations in nasopharyn-geal cancer.