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

Objective: To 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.

Methods: The 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.

Results: It 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.

Conclusion: 20(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.