Objective To explore the relationship between the changes in activity of caspase-8 and apoptosis of HepG2 cells induced by 5-fluorouracil(5-Fu). MethodsThe HepG2 cells were treated with 5-Fu. The caspase-8 activity was detected using caspase-8 Fluorescent Assay Kit. The apoptotic rates of HepG2 cells induced by 5-Fu with or without the caspase-8 inhibitor IETD-FMK were measured by flow cytometry. ResultsAfter treatment with 10 -2mol/L 5-Fu, the caspase-8 activity in HepG2 cells increased gradually and reached the peak at 16 h. With the concentration of 5-Fu increasing, the caspase-8 activity also elevated, the group of high concentration was significantly higher than that of low concentration(P

Background and purpose:The scarcity in quantity and continuous differentiation ability severely compromise the isolation and purification of cancer stem cells(CSCs).The existing sorting methods can only enrich CSCs as a heterogeneous population.However,more primitive CSCs closer to the source still have not been identified.Based on the CSC hypothesis,we hereby explored the possibility of isolation,culture,purification and identification of murine breast cancer stem cells in suspension culture combined with anticancer regimens. Methods :TM40D murine breast cancer cells were cultured in serum-free medium.The expression of CD44 + CD24-was measured by flow cytometry.Cells from the passage of TM40D cells with the highest expression of CD44 + CD24-were treated in combination with anticancer agents pacilitaxel and epirubicin at different peak plasma concentrations(PPC) for 24 hours,and then maintained under suspension culture.The rate of apoptosis was examined by flow cytometry with Annexin-V FITC/PI double staining method.Selected cells in different amounts were injected subcutaneously into BALB/C mice to observe tumor formation. Results :Cells of passage 10 in suspension culture had the highest percentage of CD44 + CD24-(about 77 percent).As few as 100 cells in 0.35 PPC could generate tumors in BALB/C mice. Conclusions :TM40D cell line contains breast cancer stem cells.This study suggested that suspension culture combined with anticancer regimens is a feasible approach for screening tumor stem cells.