[Curcumin Combined with Thalidomide Inhibits Proliferation of KG-1 Cells and Its Related Mechanisms].

Objective: To investigate the effects of curcumin combined with thalidomide on the proliferation and apoptosis of acute myeloid leukemia KG-1 cells, and its correlation with B-cell lymphoma-xL (Bcl-xL), signal transducer and activator of transcription 3 (STAT3).
Methods: MTT assay was used to detect the proliferation of KG-1 cells and screen the optimal combined concentration of curcumin and thalidomide. The effects of curcumin, thalidomide and their combination on the proliferation and apoptosis of KG-1 cells were analyzed by MTT method and flow cytometry, respectively. The mRNA expression levels of STAT3 and Bcl-xL in single-drug group, two-drug combination group and control group (untreated cells) were detected by real-time quantitative PCR.
Results: Both curcumin and thalidomide inhibited the proliferation of KG-1 cells in a concentration-dependent manner in the range of 20-100 μmol/L ( r =0.657, r =0.681). The IC ₅₀ value of curcumin and thalidomide at 48 h was (42.07±0.50) μmol/L and (57.01±2.39) μmol/L, respectively. The cell proliferation inhibition rate of curcumin (40 μmol/L) + thalidomide (60 μmol/L) was (86.67±1.53)%, which was significantly higher than (51.67±1.15)% of curcumin (40 μmol/L) and (55.33±1.53)% of thalidomide (60 μmol/L) (both P < 0.05). Treated with curcumin and thalidomide alone or in combination, the apoptosis rate of KT-1 cells was (18.67±2.08)%, (21.33±2.52)%, and (46.67±1.53)%, respectively, which was significantly higher than (0.72±0.03)% of control group (all P < 0.05). The cell apoptosis rate of two-drug combination group was significantly higher than that of single-drug group (both P < 0.05). Compared with the control group, the mRNA expressions of STAT3 and Bcl-xL in single-drug group, two-drug combination group were significantly decreased (both P < 0.05). Compared with single-drug group, the mRNA expressions of STAT3 and Bcl-xL in two-drug combination group were also significantly decreased (both P < 0.05).
Conclusion: Curcumin combined with thalidomide can synergistically down-regulate the expression of STAT3 and Bcl-xL, inhibit the proliferation of KG-1 cells, and induce apoptosis.