ABSTRACT
Objective:To explore the effects of apatinib on the proliferation and apoptosis of FLT3-ITD mutant acute myeloid leukemia (AML) cells, and to explore the related mechanisms.Methods:The logarithmic growth phase FLT3-ITD mutant AML cell lines MV4-11 and MOLM-13 were treated with different concentration of apatinib for 48 hours. The cell proliferation was detected by CCK-8 method. Flow cytometry was performed to examine the effect of apatinib on apoptosis. The cell mitochondrial membrane potential changes were detected by JC-1. Then the expression changes of vascular endothelial growth factor receptor 2 (VEGFR2) pathway-related proteins were examined by Western blot.Results:Apatinib had proliferation inhibitory effects on both MV4-11 and MOLM-13 cells, and the half-maximal inhibitory concentration (IC 50) at 48 hours was (2.23±0.42) μmol/L and (4.08±2.62) μmol/L, respectively. After exposure to apatinib with increasing concentrations (10, 20, 30, and 40 μmol/L) for 48 h hours, the percentage of apoptotic cells was significantly increased in MV4-11 cells [(81.95±1.15)%, (88.80±0.23)%, (97.46±0.49)%, and (99.29±0.05)%] and MOLM13 cells [(47.30±0.87)%, (67.00±3.71)%, (82.60±2.89)%, and (98.06±5.34)%] in a dose-dependent manner, and the differences were statistically significant ( F = 6 915.0, P < 0.01; F = 5 385.0, P < 0.01). Detection of mitochondrial membrane potential by JC-1 method showed that after MV4-11 and MOLM-13 cells were treated by 10, 20, 30, and 40 μmol/L apatinib for 24 hours, the JC-1 aggregate/monomer mean fluorescence intensity (MFI) ratios were 0.45±0.06, 0.19±0.07, 0.12±0.03, 0.09±0.01, and 0.84±0.05, 0.66±0.13, 0.35±0.11, 0.27±0.02, which were different from the control group (0.67±0.15 and 0.97±0.42), and the differences were statistically significant ( F = 372.3, P < 0.05; F = 276.4, P < 0.05). Western blot was performed to detect different concentration of apatinib (2.5, 5.0 and 10.0 μmol/L) on the MV4-11 cells for 24 hours, the results showed that apatinib could down-regulate the phosphorylation of VEGFR2, Src and Stat3 in a dose-dependent manner. Conclusions:Apatinib can inhibit cell proliferation and induce apoptosis in AML with FLT3-ITD mutation. The possible mechanism is related to the down-regulation of phosphorylation of VEGFR2 and its downstream targets Src and Stat3.
ABSTRACT
Objective:To investigate the effects of triptolide (TPL) and BET protein inhibitor JQ1 on proliferation inhibition and apoptosis induction of MLL-rearranged acute myeloid leukemia (AML) cell line MV4-11, and to explore their synergistic mechanisms.Methods:MV4-11 cells in logarithmic growth phase were treated with different concentrations (100, 200, 300, and 400 nmol/L) of JQ1, 4 nmol/L TPL or different concentrations of JQ1 combined with 4 nmol/L TPL for 48 h. Cell proliferation was detected by CCK-8 method, apoptosis was detected by flow cytometry (FCM), mitochondrial membrane potential was detected by JC-1 method, and expressions of mitochondrial apoptosis pathway-related proteins were detected by Western blot.Results:The 50% inhibitory concentration ( IC50) value of MV4-11 cells treated with JQ1 for 48 h was (283.9±10.7) nmol/L. However, 4 nmol/L TPL significantly enhanced the inhibitory effect of JQ1 on proliferation of MV4-11 cells, the IC50 value of MV4-11 cells treated with JQ1 combined with TPL was (148.1±2.6) nmol/L, and the difference was statistically significant ( t = 25.31, P = 0.029). The result of FCM assay showed that compared with the JQ1 alone group [(9.6±2.3)%, (12.6±1.4)%, (19.5±3.3)%, and (22.7±2.1)%], 4 nmol/L TPL combined with different concentrations (100, 200, 300, and 400 nmol/L) of JQ1 acted on MV4-11 cells for 48 h, the proportions of apoptotic cells were (16.4±1.9)%, (27.5±2.1)%, (32.9±3.6)%, and (35.5±3.0)%, respectively, the difference was statistically significant ( F = 9.25, P < 0.01). After treated with 4 nmol/L TPL and JQ1 for 12 h, the level of cell membrane potential in MV4-11 cells was significantly lower than that of JQ1 single agent group, and the difference was statistically significant ( P < 0.05). After treated by 4 nmol/L TPL combined with JQ1 for 24 h, the levels of anti-apoptotic proteins bcl-2 and Mcl-1 decreased, and the level of pro-apoptotic protein bax increased. Conclusion:TPL can significantly enhance the proliferation inhibition and apoptosis induction effects of BET protein inhibitor JQ1 on MLL-rearranged AML cells, and the mechanism may be related to enhancing the mitochondrial apoptosis pathway.