Objectives: A side population (SP) of cells can be separated from diverse cancer cell lines by a fluorescence-activated cell sorter (FACS) and show stem cell-like characteristics. To gain more information about SP phenotypes, we performed a series of characterizations of SP cells.
Methods: We isolated SP cells from the lung cancer cell line Glc-82 via FACS. Their capability of multilineage differentiation, self-renewal and tumorigenicity were examined both in vitro and in vivo. Their sensitivity to anticancer drugs was also detected by Methyl-thiazol-diphenyl tetrazolium assay. The expression of cell surface molecules including ABCG2, HERs and CD133 was analyzed with a flow cytometer.
Results: SP cells made up an average of 14.5% of the total cell population and were more tumorigenic than non-SP cells in vivo. The growth rate of SP cells was higher than that of the unsorted cells and non-SP cells, and the repopulation of SP cells occurred more rapidly. Moreover, the SP cells expressed elevated levels of ABCG2 protein and showed augmented resistance to multiple chemotherapeutic and targeted drugs, when compared to non-SP cells. In addition, the expression of epidermal growth factor receptor protein and CD133 were higher in SP cells than in non-SP cells.
Conclusions: We suggest that the SP cells in the Glc-82 cell line are enriched with cancer stem cells.
Keywords: ABCG2; EGFR; multiple drug resistance; side population.
© 2011 Tianjin Lung Cancer Institute and Blackwell Publishing Asia Pty. Ltd.