OBJECTIVETo explore the effect of recombinant human erythropoietin (rhEPO) on myeloma cell line MPC-11 in vitro and its anti-tumor mechamism so as to provide the theoretic evidence for treatment of multiple myeloma by using rhEPO.

METHODSMPC-11 cells were cultured in RPMI 1640 medium, then the MPC-11 cells in logarithmic growth phase were seed in 96 well culture plates at a density of 1×10/ml cells with 100 µl per well. For all the experiments, the control and rhEPO groups were set up, and the rhEPO group was divided into different concentration groups: 20, 40, 60, 80, 100, 200 and 400 rhEPO U/ml. The cultured MPC-11 cells in each groups were collected at day 1, 2, 3, 4, 5 and 6, and the viability of MPC-11 cells was assayed by using CCK-8 method, the MPC-11 cell apoptosis was detected by flow cytometry with Annexin V/PI double staining, the levels of IL-6, IgG and kappa light chain in cell supernatant were detected by ILISA.

RESULTSThe apoptosis rate in MPC-11 cells treated with 200 U/ml of rhEPO at day 21 was significantly higher than that in control group(P<0.05); the apoptosis rate in MPC-11 cells treated with 400 U/ml of rhEPO at day 10, 15, 21 was higher than that in control group at same time points, respectively (P<0.05), suggesting that the MPC-11 cell apoptosis rate was enhanced with increase of rhEPO concentration and prolonging of culture time(P<0.05), the IL-6 level in supernatant of cell treated with 400 U/ml of rhEOP for 15 days was lower than that in control group(P<0.05), while the IL-6 level in supernatant of cells treated with 100, 200, 400 U/ml of rhEPO for 21 days decreased (P<0.05); The levels of IgG and kappa light chain in supernatant of cells treated with 400 U/ml of rhEPO for 21 days all were significantly lower than those in control group(P<0.05).

CONCLUSIONThe rhEPO can induce apoptosis of MPC-11 cells with concentration- and time-dependent manner, and can reduce levels of IgG, kappa light chain secreted by MPC-11 cells with time-dependent manner.