Figure 6

Stable SCC9 cells expressing MT1-MMP (SCC9-M) presented cancer stem cell (CSC)-like properties of expressing CSC markers, self-renewal and resistance to drugs. (A) Cell-cycle analysis of stable SCC9 cells expressing empty vector (SCC9-N) and MT1-MMP (SCC9-M). (B) Growth curves of SCC9-N and SCC9-M cells. The bar represents the mean ± s.d. (C and D) The flow cytometry analysis of CSC markers, including the CD24, CD44, and CD133 expression, in the SCC9-N and SCC9-M cells. The corresponding mouse immunoglobulins conjugated to PE or APC were used as isotype controls in each experiment. (E) Images of colonies stained with crystal violet for the SCC9-N and SCC9-M cells. (F) The pictures of cells forming single colony under microscopy. The photographs were taken at ×40 magnification. Bar, 100 μm. (G) Quantification of colonies formed by the SCC9-N and SCC9-M cells. The bar represents the mean ± s.d. **P<0.01. (H) The survival rate of SCC9-N and SCC9-M cells by the treatment with mitomycin after 24 h. Each bar represents the mean ± s.d. *P<0.05, **P<0.01.