Effects of apatinib on the proliferation and apoptosis of FLT3-ITD mutant acute myeloid leukemia MV4-11 and MOLM-13 cells and their mechanisms / 白血病·淋巴瘤

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.

Co-operation of ABT-199 and gemcitabine in impeding DNA damage repair and inducing cell apoptosis for synergistic therapy of T-cell acute lymphoblastic leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is a high-risk subtype of acute lymphoblastic leukemia with limited therapeutic options available. Here, we evaluated the therapeutic potential of the combination of the Bcl-2 antagonist ABT-199 and cytotoxic agent gemcitabine in T-ALL cell lines. Our results showed that the combination of ABT-199 and gemcitabine exhibited synergistic cytotoxicity and induced significant apoptosis in human T-ALL cell lines (Jurkat and Molt4). The augmented apoptosis induced by combination treatment was accompanied by the greater extent of mitochondrial depolarization and enhanced DNA damage. Importantly, single agent induced DNA damage alone but did not inhibit RAD51/BRCA1-mediated repair for DNA double-strand breaks. In contrast, the combination of ABT-199 and gemcitabine disrupted RAD51/BRCA1-dependent DNA repair and remarkably activated caspase-3 and PARP to trigger apoptosis. Moreover, ABT-199 exerted an antagonistic action towards Bcl-2 and Bcl-xL, but to a certain extent moderately increased Mcl-1 level that could be compromised by gemcitabine. In conclusion, our study showed that the combination of ABT-199 and gemcitabine exhibited synergistic cytotoxicity in T-ALL cells by cooperatively targeting DNA damage repair pathway and Bcl-2 family proteins.

Inhibition effect of disulfiram combined with Cu on the growth of human Burkitt lymphoma cell xenografts in nude mice / 肿瘤研究与临床

Objective To investigate the effects of disulfiram (DS) combined with Cu on the human Burkitt lymphoma cell xenografts in nude mice.Methods Burkitt lymphoma xenograft was established by subcutaneous injection of Raji cell into nude mice after 2 Gy whole body X-irradiation (1×107 Raji cells were resuspended in 200 μl saline).18 bearing tumor mice were randomly divided into control group,DS group and DS/Cu group.During the experiment,the effects of DS/Cu on the nude mice with tumors were examined,including the tumor volumes,weights and the growth curves of xenograft tumor.Histopathological examination of tumor tissue was observed with optical microscape.The protein expression levels of p-JNK and c-jun were also detected by Western blot.Results Subsequent tumor size and weight in DS or DS/Cu-treated animals were (67.71±2.15) mm3,(33.35±7.74) mm3 and (43.35±4.22) mg,(18.05±2.88) mg.One-way ANOVA analysis indicated that the tumor size and weight in DS or DS/Cu-treated animals were reduced significantly relative to tumors in vehicle-treated animals (F =27.579,P =0.000;F =16.369,P =0.000).Furthermore,multiple comparisons revealed that the DS or DS/Cu-treated animals had significantly reduced tumor size and weight compared with control animals (all P ＜ 0.05).There were significant differences in tumor size and weight between DS or DS/Cu-treated animals (both P ＜ 0.05).Tumor inhibition rates in DS or DS/Cu group were 63.48 ％ and 80.24 ％,respectively.An increase of apoptosis changes in the xenograft tumor cells in DS or DS/Cu treated mice were more significant.Westem blot showed that the p-JNK and c-jun protein expressions in the tumors were improved after the DS or DS/Cu treatment,more obvious in DS/Cu treatment.Conclusion DS/Cu can inhibit the growth of xenografts,and one possible mechanism may involve the regulation of JNK signal pathway.