Abstract:

【Abstract】 Objective To investigate the expression of stem cell marker adenosine triphosphate （ATP）-binding cassette transporter 2 （ABCG2） in the tissue and side population （SP） of a cell line A431 of human cutaneous squamous cell carcinoma （SCC）. Methods SP cells were separated by flow cytometry from cultured A431 cells. Methyl thiazolyl tetrazolium （MTT） assay was used to evaluate the proliferative ability of, reverse transcription-PCR to determine the expression of ABCG2 in, SP and non-SP cells. Immunohistochemistry （MaxVision method） was carried out to detect the expression of ABCG2 protein in tissue specimens from 10 patients with SCC. Results SP cells existed in cultured A431 cells, and accounted for about 1.1% of A431 cells. The SP cells had a stronger growth and colony-forming ability than non-SP cells did. The number of cell clones formed by SP cells and non-SP cells was 114.8 ± 4.95 and 44.5 ± 3.67, respectively, per well in a 24-well plate （t = 27.92, P ＜ 0.01）. The expression level of ABCG2 mRNA was significantly higher in SP cells than in non-SP cells （t = 5.22, P ＜ 0.01）. There existed a small number of ABCG2 positive cells in SCC tissue, and ABCG2 was mainly expressed in the cytoplasm and membrane of tumor cells. Conclusions SP cells exist in A431 cells, which have characteristics of stem cells and highly express ABCG2. ABCG2 may be a potential stem cell surface marker of SCC.

Key words: cutaneous sqamous cell carcinoma