Effects of parthenolide on the surface antigens and proliferation of human multiple myeloma cell line in vitro

OBJECTIVE To investigate the effect of parthenolide(PTL) on the surface antigens and proliferation of multiple myeloma(MM) cells,in order to study the mechanism of its anti-myeloma effect.METHODS RPMI8226,a human MM cell line,was cultured with various concentrations of PTL for different time.Then,the cultured cells were stained using fluorescein isothiocyanate(FITC)-,phycoerythrin(PE)-,and CY5-conjugated antibodies for surface antigen expression,and the changes of surface antigens were examined by flow cytometry.Cell proliferation was evaluated by MTT assay,and cell apoptosis was examined using Annexin V and PI by flow cytometry.RESULTS MM cells expressing high levels of surface CD38,CD45,CD49e,MPC-1,and CD56 were identified.However,CD19 was expressed partially at rate of(45±(3.5)%),MM cells could be divided into two groups,CD56~(+)CD19~(-)and CD56~(+)CD19~(+).After the cells being treated for 48 h with PTL at various concentrations from 2 to 10 μmol·L~(-1),no changes could be detected in expressing levels of surface CD38,CD45,CD49e,MPC-1 and CD56.However,significant changes could be found in percentages of the two groups of cells expressing CD56~(+)CD19~(-) and CD56~(+)CD19~(+),respectively,and the percentage of CD56~(+)CD19~(+) cells was enhanced by PTL in a dose-dependent manner.Cell proliferation was inhibited significantly and apoptosis was promoted significantly by PTL in a time-and dose-dependent manner.CONCLUSION Percentage of CD56~(+)CD19~(+) cells can be enhanced while the proliferation can be inhibited significantly and apoptosis was promoted significantly after short term of treating MM cells with PTL.It remains to be clarified that whether induced expression of surface CD19 on CD56~(+)CD19~(-) MM cells or induced apoptosis of CD56~(+)CD19~(-) MM cells should be responsible for the anti-myeloma effect of PTL.