Abstract:

[Abstract] Objective  To investigate the killing effects of dendritic cell (DC) derived from stem cells of chronic myelocytic leukemia (CML) co-cultured with cytokine induced killer (CIK) on leukemia stem cells of K562/A02 cells. Methods  The marrow mononuclear cells were isolated from CML donors. CD34+CD38- cells were sorted by flow cytometry, cultured and induced to DC. The bone marrow mononuclear cells from the same donors were induced to CIK. DC and CIK were co-cultured to determine the apoptosis proapoptosis and killing effect on leukemia stem cells of K562/A02 cells by flow cytometry. Morphologies of cultured cells were examined under optical microscopy．The immune phenotypes of DC and CIK and the P-gp expressions of K562/A02 and DC were detected by flow cytometry. The expressions of BCR/ABL fusion gene of LSC and DC were detected by fluorescence in situ hybridization (FISH). Results  DCs were successfully induced from leukemia stem cells. The positive expression rate of DC’s P-gp was about 51.8%. The expression rates of CD40, CD80, CD83, CD86 and HLA-DR were increased in DC co-cultured with CIK. The mature immune phenotypes of CD3, CD8 and CD56 were significantly increased in CIK co-cultured with DC（P < 0.01）. There were significant differences in the killing effects on CD34+CD38- cells between DC-CIK group and CIK group. DC-CIK induced apoptosis of K562/A02 cells，with the apoptot? ic rate increased from (32.56±3.20)% to (40.21±3.09)%，compared with that of CIK, the difference was significant（P < 0.01）, but it showed no evident effect on apoptosis of CD34+CD38-cells．Conclusion  The functions of DC derived from stem cells were normal. DC co-cultured with CIK can effectively kill stem cells from multidrug resistant cells，but it has no evident apoptosis effect on stem cells．

Key words: leukemia, myelogenous, chronic, BCR-ABL positive, stem cells, dendritic cells, killer cells, P糖蛋白