Influences of co-culture with primary bone marrow stromal cells on imatinib sensitivity and cell cycles of K562 cells / 中国组织工程研究

ABSTRACT

BACKGROUND:Leukemia cells can obtain drug resistance phenotype mediated by adhesion to bone marrow stromal cells. But, for chronic myelogenous leukemia with adhesion functional defects, the role and mechanism of bone marrow stromal cells in imatinib-resistant formation remain unclear. OBJECTIVE:To construct the co-cultured model of bone marrow stromal cells-K562 cells and to investigate the influences of the co-culture with bone marrow stromal cells from the patients with chronic myelogenous leukemia on imatinib sensitivity of K562 cells and cellcycle. METHODS:The co-culture model was constructed by co-culturing K562 cells with bone marrow stromal cells isolated and cultured from the patients with chronic myelogenous leukemia. The IC50 values of K562 cells exposed to imatinib were quantified by MTT assay. The apoptotic rates of K562 cells exposed to 0.5μmol/L imatinib for 72 hours were detected by flow cytometry through Annexin V-FIT/PI labeling. The cellcycles, cellcycle protein (cyclin A, cyclin D1 and cyclin E) expression of K562 cells co-cultured with bone marrow stromal cells for 72 hours were analyzed by flow cytometry.RESULTS AND CONCLUSION:The IC50 values of co-culture group and suspension culture group were respectively (0.52±0.02)μmol/L and (1.27±0.05)μmol/L, and their comparison showed significant differences (P<0.01). After 72 hours of treatment with 0.5μmol/L imatinib, the apoptotic rates in the co-culture group and suspension culture group were respectively (15.48±4.17)%and (32.01±6.83)%, and their comparison showed significant differences (P<0.01). The percentages of G0-G1 phase of K562 cells co-cultured with bone marrow stromal cells for 72 hours were (48.81±8.27)%, which were significantly higher than the suspension culture group (25.78±3.26%) (P<0.01). The co-culture with bone marrow stromal cells from the patients with chronic myelogenous leukemia could mediate K562 cells resistance to imatinib. The mechanism was possibly related with G0/G1 arrest of K562 cells induced by co-culture with bone marrow stromal cells.