OBJECTIVETo explore the anti-myeloma effect of suberoylanilide hydroxamic acid (SAHA) and on mouse myeloma cell line SP2/0 in vitro and in vivo and its mechanism.

METHODSThe inhibitory effect of SAHA on SP2/0 cells was measured by CCK-8 assay,and the apoptosis and cell cycle were analyzed by flow cytometry FACS. The protein expression of Caspase-3 and p53 of SP2/0 cells treated with SAHA were examined by Western blot. Annexin V/7-AAD double staining was performed to detect the apoptosis of SP2/0 induced by SAHA in vitro. SP2/0 cells (1×10) resuspended in 200 µl PBS were inoculated subcutaneously and intravenously into BALB/c mice, so as to establish aggressive or non-aggressive myeloma-bearing mouse models respectively. On day 3 after modeling, mice received SAHA or vehicle control treatment by intraperitoneal injection. The dose of SAHA was 60 mg/kg·d, 5 times a week for 3 weeks.

RESULTSIn SAHA-treated SP2/0 cells, the proliferation inhibition rate and apoptotic cells increased in a dose dependent manner. Also, SAHA significantly increased the ratio of cells in G phase and decreased in S phase. Molecular mechanisms of apoptosis and cell cycle arrest of SP2/0 induced by SAHA partly correlated with up-regulating the expression level of Caspase-3 and p53. In the non-aggressive myeloma-bearing mice, SP2/0 cells disappeared in peripheral blood after SAHA treatment. In the aggressive myeloma-bearing mice, inhibition of tumor growth and prolongation of the cell survival were observed after SAHA treatment.

CONCLUSIONSAHA inhibited SP2/0 cell proliferation, this effect associates with inducing apoptosis and cell cycle arrest, the mechanism of SAHA ralates partly with activating Caspase-3 and p53 pathway.