Apoptosis of acute myeloid leukemia HL-60 cells induced by CDK inhibitor SNS-032 and its molecular mechanisms / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of cycle-dependent kinase (CDK) inhibitor SNS-032 on apoptosis in human acute myeloid leukemia (AML) HL-60 cells and its molecular mechanisms.</p><p><b>METHODS</b>Cultured AML HL-60 cells were treated with various concentrations of SNS-032. Cell apoptosis was determined with flow cytometry;cell viability was measured by MTT assay; the profiles of microRNA expression of HL-60 cells were analyzed by microRNA microarray;the protein expressions of JAK2/STAT3 pathway were detected by Western blotting.</p><p><b>RESULTS</b>Apoptosis of AML HL-60 cells was induced by SNS-032; the rate of apoptosis was (5.9±1.7)%, (12.1±3.1)% and (59.4±3.6)% when HL-60 cells were treated with 0,100 and 200 nmol/L SNS-032. MicroRNA microarray analysis revealed that the levels of miR-30a, miR-183, miR-20b, miR-26b, miR-20a, miR-589, miR-107, miR-181a, miR-106a, miR-17 and miR-378c were down-regulated by SNS-032,whereas the levels of miR-320a and miR-H7* were up-regulated. Western blotting showed that SNS-032 strongly inhibited phosphorylation of STAT3 and protein expression of JAK2,C-MYC and MCL-1.</p><p><b>CONCLUSION</b>CDK inhibitor SNS-032 can induce apoptosis of AML HL-60 cells, which is associated with the inhibition of MCL-1,C-MYC and JAK2/STAT3, and down-regulation of miR-17-92 family.</p>

Matrine and CYC116 synergistically inhibit growth and induce apoptosis in multiple myeloma cells / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate whether CYC116 can potentiate matrine-dependent growth inhibition and apoptosis in multiple myeloma (MM) cells.</p><p><b>METHODS</b>The dose response relationship of matrine to dexamethasone-resistant and dexamethasone-sensitive MM cells was first established. Myeloma RPMI8226 cells were treated with matrine alone or combined with CYC116 for 24 h. Cell proliferation was measured using an MTT assay and apoptosis induction was evaluated by flow cytometry. Activation of the caspase pathway and expression of apoptosis regulator proteins were detected by Western blotting.</p><p><b>RESULTS</b>Matrine significantly induced growth arrest and apoptosis in both drug-resistant and drug-sensitive MM cells. Treatment with the combination of matrine and CYC116 had a stronger cytotoxic effect on MM cells than did single drug treatments. Enhanced apoptosis observed following the combined treatment of matrine and CYC116 was associated with higher levels of activation of caspase-9, caspase-3, and poly adenosine diphosphate ribose polymerase (PARP) and down-regulation of the anti-apoptotic proteins Bcl-2 and Mcl-1 and the signaling proteins p-Akt and nuclear factor κB (NF-κB).</p><p><b>CONCLUSION</b>CYC116 enhances the growth inhibitory and apoptotic effects of matrine on MM cells.</p>

ITF-2357 on inhibition myeloid leukemic cell lines cells proliferation in vitro and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the effect of ITF2357, a novel histone deacetylase (HDAC) inhibitor, on the growth, differentiation and apoptosis of acute myeloid leukemic (AML) cells and its mechanism.</p><p><b>METHODS</b>AML cell lines kasumi-1 cells as a model for AML1-ETO positive, and THP1 cells for AML1-ETO negative, the leukemic cells proliferation was analyzed by MTT assay, expression of myeloid-specific differentiation antigen and cell cycle by flow cytometry, cell apoptosis by annexin V staining and flow cytometry. AML1-ETO, acetyl-histone, and caspase protein was analyzed by Western blot.</p><p><b>RESULTS</b>0.5 µmol/L ITF2357 treatment significantly inhibited kasumi-1 cells proliferation, with the 48 h half inhibitory concentration (IC(50)) of 0.1 µmol/L. The initial inhibitory concentration of THP1 cell line was 5 µmol/L. ITF 2357 induced apoptosis of kasumi-1 cells in a time- and dose-dependent manner. A dose-dependent increase in early apoptosis occurred at 24 hours treatment and in late apoptosis at 48 hours treatment by ITF2357. Early apoptosis cells increased from (1.44 ± 1.52)% to (24.51 ± 5.79)%. Late apoptosis cells increased from (2.37 ± 2.8)% to (63.66 ± 1.56)%. ITF2357 induced AML1-ETO degradation by caspase-dependent pathway. 0.25 µmol/L ITF2357 induced a time- and dose-dependent increase in expression of myeloid cell surface protein CD13 and CD15. 5 µmol/L ITF2357 blocked the cells at G(0)/G(1) phase, G(0)/G(1) cells increased from (39.69 ± 6.56)% to (79.2 ± 6.51)% and s-phase cells declined from (60.12 ± 3.29)% to (18.97 ± 6.62)%. Kasumi-1 cells incubated with 0.5 µmol/L of ITF2357, AML1-ETO protein began to decrease at 24 hours and could hardly be detected at 96 hours. ITF2357 induced AML1/ETO degradation through a caspase-dependent mechanism. At the same time, acetylated H3 and H4 increased.</p><p><b>CONCLUSION</b>Low-dose HDAC inhibitor ITF2357 can effectively inhibit the AML cells proliferation, especially for AML1-ETO positive AML cells. It inhibits Kasumi-1 cells proliferation degradation of AML1-ETO protein expression, blocks the cells at G(0)/G(1) phase, and induces apoptosis and differentiation of the cells.</p>

Synergistic effect of histone deacetylase inhibitor suberoylanilide hydroxamic acid with imatinib on K562 cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate synergistically killing effect of histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) combined with imatinib on human chronic myeloid leukemia (CML) cell line.</p><p><b>METHODS</b>K562 cells were co-treated with SAHA and imatinib. Cell growth was measured by MTT assay. Apoptosis was determined using Hoechst staining apoptosis detection kit and flow cytometric analysis. Activation of Caspase pathway, expression of Bcr-Abl and its downstream target genes, and expression of anti-apoptotic proteins were detected by Western blot.</p><p><b>RESULTS</b>SAHA synergized the cytotoxicity of imatinib against leukemia K562 cells, concomitantly with increased apoptosis and enhanced activation of Caspase-3, -8 and PRAP. The combination therapy resulted in significantly lower levels of Bcr-Abl,phosphorylated Bcr-Abl compared to treatment with either SAHA or imatinib alone. Furthermore,the co-treatment resulted in down-regulation of anti-apoptotic protein Mcl-1 expression. Also,marked down-regulated expression of JAK2,STAT5,and phosphorylated STAT5 was detected in the combination therapy.</p><p><b>CONCLUSION</b>Combining HDAC inhibitor SAHA with imatinib can kill CML cells synergistically by inhibiting cell growth and inducing apoptosis, which is associated with activation of Caspase pathway and regulation of anti-apoptotic proteins.</p>