OBJECTIVETo explore the effect of 20 (S)-ginsenoside Rg3 [20 (S)-Rg3] on the proliferation inhibition and secretion of vascular endothelial growth factor (VEGF) of multiple myeloma (MM) cell line U266.

METHODSThe proliferation inhibition rate of U266 cells after treatment with different doses of 20 (S)-Rg3 was detected by MTT method, the cell cycle and apoptosis by flow cytometry, the expression of apoptosis related proteins of caspase-3, 8 and 9 by Western blot, VEGF concentration in the culture supernatant by ELISA.

RESULTSIt showed that 20 (S)-Rg3 could inhibit the proliferation of U266 in a dose-dependent manner (P<0.05) with IC50 of (71.07 ± 2.63)μmol/L and (44.06 ± 3.98) μmol/L at 24 h and 48 h, respectively. VEGF concentration in the culture supernatant showed a dosedependent reduction (P<0.05), decreased from (419.93 ± 36.76) pg/106 cells in the control group to (314.82 ± 27.05) pg/106 cells in 80 μmol/L 20 (S)-Rg3 treated group by ELISA assay. Flow cytometry with Annexin-V/PI double staining revealed that 20(S)-Rg3 may induce U266 cells apoptosis in a concentration-dependent manner from (0.51 ± 0.05)% at control group to (8.32 ± 0.83)%, (10.72 ± 1.29)% and (15.27 ± 2.26)% at 20, 40 and 80 μmol/L treatment groups, respectively (P<0.05). Flow cytometry with PI staining showed that the ratio of cells in G0/G1 phase increased from (49.11 ± 1.71)% to (52.72 ± 7.75)%, (60.29 ± 5.76)% and (61.81 ± 3.46)%, respectively (P<0.05). Western blot analysis indicated that the expression of caspase-3, 8 and 9 declined, and that of cleaved-caspase-3, 8 and 9 significantly increased (P<0.05) with 20 (S)-Rg3 concentration increased.

CONCLUSION20(S)-Rg3 can inhibit the proliferation of U266 cells by cell cycle arrest in G1 phase and induce cell apoptosis by increasing the expressions of cleaved-caspase-3, -8 and -9. It can also inhibit VEGF secretion of U266 cells, which makes it a potential agent for multiple myeloma therapy.