Phenotypic analysis of common cancer stem cell markers and cell sorting in lung cancer cell line A549 / 中国组织工程研究

ABSTRACT

BACKGROUND: It has been widely reported that the most types of cancer are probably originated from cancer stem cells (CSCs) which are subpopulations of tumor cells. Recent studies also suggested that lung cancer could arise from CSCs. However, the phenotypic characteristics of CSCs in lung cancer have not been precisely described.OBJECTIVE: To systematically analyze the expression of the most common CSC markers in cell line A549.METHODS: A549 cells were cultured for 1 week under the condition of conventional high glucose. After that, flow cytometry was used to assess the expression of putative stem cell markers, including CD133, CD24, CD44 and ABCG2.Cells were then sorted according to the expression of CD44 and CD24 markers by fluorescence-activated cell sorting (FACS) and characterized using their sphere-forming capacity in serum free medium supplemented with several growth factors.RESULTS AND CONCLUSION: A549 cells expressed the CSC markers CD44 and CD24 at 64.23％ and 58.62％,whereas the expression of both ABCG2 and CD133 was around 0.9％. Double-positive CD44/133 populations were rare.CD44+/CD24+ and CD44+/CD24- subpopulations respectively exhibited 54.64％ and 23.38％ expression. CD44+/CD24+ and CD44+/CD24- subsets were sorted by FACS. Both isolated subpopulations formed spheres in the serum free medium supplemented with basic fibroblast growth factor and epidermal growth factor. However, there was no significant difference in the sphere formation efficiency among CD44+/CD24+ and CD44+/CD24- subsets as well as A549 cells. Our findings suggest that CD44 and CD24 cannot be considered as potential markers for isolating lung CSCs in cell line A549, and further investigation using in vivo assays is required.