Transcriptome Analysis of Chronic Myelogenous Leukemia Cell Line with Imatinib Resistance / 中国实验血液学杂志

OBJECTIVE@#To investigate the regulation of chronic myelogenous leukemia （CML） imatinib resistant genes, in order to improve the therapeutic effect of CML imatinib resistant patients.@*METHODS@#The human CML cell line K562 and imatinib-resistant K562 cells (K562/G01) were collected, and transcriptome of the cells were achieved by RNA-seq. The sequencing data were analyzed by using standard procedures.@*RESULTS@#Compared with K562 cells, 464 genes were significantly changed in K562/G01 cells, including 163 up-regulated and 301 down-regulated genes. The GO function annotation analysis and KEGG pathway analysis results showed that the differentially expressed genes were mainly involved in biological processes such as oxidative phosphorylation, localization to protein organelle, ribonucleoprotein complex biogenesis and so on. Gene Set Enrichment Analysis (GSEA) plots showed that 5 gene-sets were up-regulated in K562/G01 significantly, including the pathway of TGF-beta, mTOR and CML.@*CONCLUSION@#CML imatinib resistance is associated with oxidative phosphorylation, during which the pathway of TGF-beta and mTOR are significantly up-regulated.

Mechanism of mTOR Pathway in K562 cell Apoptosis Induced by Homoharringtonine / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of homoharringtonine (HHT) on proliferation and apoptosis of CML cell line K562 cells and to explore its possible mechanism through mTOR pathway.</p><p><b>METHODS</b>K562 cells were cultured with different concentrations of HHT or in its combination with mTOR inhibitor rapamycin (RAPA) for 24 hours. The cell viability was analyzed by CCK-8 assay, the cell apoptosis was detected by flow cytometry, the expressions of BCL-6, Caspase-3 and mTOR signal pathway related proteins was assayed by Western blot, the expression of BCL-6 mRNA was determined by RT-PCR.</p><p><b>RESULTS</b>The HHT inhibited proliferation and induced apoptosis of K562 cells in a concentration-dependent manner(r=0.970). With the increasing of HHT concentration, the expression level mTOR signal pathway related proteins increased(r=0.908), while the mRNA and protein expression levels of BCL-6 decreased(r=-0.961, r=-0.981), as compared with the HHT alone, the combination of HHT with RAPA could down-regulate the expression of mTOR signal pathway related protein and caspase-3, and up-regulated expression of BCL-6.</p><p><b>CONCLUSION</b>HHT induces apoptosis of K562 cells by inhibiting BCL-6 expression through mTOR signal pathway.</p>

Effects of PCI-32765 and Dasatinib on the Acute Lymphoblastic Leukemic Cells and Their Mechanisms / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of Btk inhibitor (PCI-32765) and BCR-ABL tyrosine kinase inhibitor (Dasatinib) on proliferation and apoptosis of acute lymphoblastic leukemia (ALL) cell lines (Sup-B15, RS4;11) and the possible mechanism.</p><p><b>METHODS</b>RS4;11 and Sup-B15 cells were treated with PCI-32765 and Dasatinib, the cell proliferation and apoptosis were detected by CCK-8, the Btk and other apoptotic proteins were detected by Western blot.</p><p><b>RESULTS</b>PCI-32765 could inhibit the proliferation of RS4;11 and Sup-B15 cells in a dose-dependent manner, Sup-B15 cells were more sensitive to PCI-32765 than RS4;11 cells, their ICwere 3 µmol/L and 8 µmol/L respectively, the difference between them was statistically significant (P<0.05). Dasatinib also could inhibit the proliferation of RS4;11 cells and Sup-B15 cells in a dose-dependent manner. The ICwas 5 µmol/L and 5 nmol/L, respectively, the difference between them was statistically very significant (P<0.01), and the inhibitory effect was enhanced by the combination of Damatinib with the PCI-32765(P<0.05). The cell survival rate decreased gradually in PCI-32765 or Dasatinib alone group and the combination group at the different time-point (8, 12, 24, 36, 48 and 72 h), the 2 drugs showed a synergistic effect on cells in a time-dependent manner. After being treated with PCI-32765 and Dasatinib, the RS4;11 and Sup-B15 cells showed that cell shrinkage, increase of cytoplasmic density, nuclear pyknosis, deviation and karyorrhexis, and increase of the apoptotic cells in the combination group, while the promotive effect of low dosage dasatinib on apoptosis of RS4;11 cells was not strong. PCI-32765 and Dasatinib could decrease the expression and activity of BCR-ABL, Btk, Lyn, Src in Sup-B15 and RS4;11 cells.</p><p><b>CONCLUSION</b>PCI-32765 or Dasatinib can inhibit the proliferation and induce the apoptosis of Sup-B15 and RS4;11 cells, PCI-32765 and Dasatinib displayed the synergistic effects. The possible mechanism may be related with the blocking of B cell receptor(BCR) signal pathway, thereby inhibiting the cell proliferation and promoting the cell apoptosis.</p>

Effect of Homoharringtonine Combined with Imatinib on the K562/G01 Cells and Its Mechanism / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effect of homoharringtonine(HHT) combined with imatinib(IM) on proliferation and apoptosis of K562/G01 cells and its potential mechanism.</p><p><b>METHODS</b>K562/G01 cells were cultured with HHT and/or IM. CCK-8 assay was used to detect cell proliferation. Cell apoptosis and phosphorylated tyrosine levels were analyzed by flow cytometry. The expression levels of p210, PI3K, p-Akt and Akt protein were determined by Western blot.</p><p><b>RESULTS</b>Compared with HHT or IM alone, drug combination significantly inhibited cell proliferation and induced apoptosis of K562/G01 cells (both P< 0.05). HHT combined with IM could inhibit the levels of phosphorylated tyrosine and phosphorylated Crkl and downregulate the expressions of p210, PI3K and p-Akt in K562/G01 cells.</p><p><b>CONCLUSION</b>HHT combined with IM can synergistically inhibit proliferation and induce apoptosis of K562/G01 cells by suppressing the p210 expression and its kinase activity.</p>

Acadesine Inhibits the Proliferation of K562 Cells and Enhances their Sensitivity to Imatinib / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of AMPK agonist Acadesine (AICAR) on growth inhibition of K562 cells and their sensitivity to imatinib (IM).</p><p><b>METHODS</b>K562 cells were cultured with different concentrations of AICAR alone or its combination with IM for 48 hours, the CCK-8 assay was used to detect cell proliferation, the cell cycle distribution and apoptosis were analyzed by flow cytometry. The expression levels of Cyclin D1, Cyclin E1 and Caspase 3 protein were determined by Western blot.</p><p><b>RESULTS</b>AICAR inhibited the proliferation of K562 cells in dose-dependent manner, and their IC50 value was 0.45 mmol/L at 48 hours. AICAR could induce arrest of K562 cells in G1 phase and down-regulated the protein expression levels of Cyclin D1 and Cyclin E1; whereas it didn't influence the cell apoptosis. Additionally, the growth inhibition of cells induced by IM was enhanced by AICAR.</p><p><b>CONCLUSION</b>AICAR can inhibit the proliferation of K562 cells by arresting the cell cycle and enhancing the sensitivity of K562 cells to IM.</p>

Effect of YM155 on Apoptosis and Autophagy of K562 Cells / 中国实验血液学杂志

<p><b>OBJECTIVE</b>This study was purposed to investigate the effect of YM155, a survivin inhibitor, on the apoptosis and autophagy of K562 cells.</p><p><b>METHODS</b>K562 cells were treated with YM155 at different concentration. Cell survival was analyzed by CCK-8 assay, the cell apoptosis was detected by flow cytometry. Survivin, BCL-2 and beclin1 mRNA expressions were determined by RT-PCR. Survivin, BCL-2, caspase-3, PARP and LC-3 protein expressions were assayed by Western blot.</p><p><b>RESULTS</b>YM155 inhibited the proliferation of K562 cells in a time- and dose-dependent manners. With the increasing of YM155 concentration and prolonging of action time, the expression levels of mRNA and protein of survivin and BCL-2 decreased, while the expression levels of caspase-3, PARP, beclin1 and LC-3 increased. Compared with the YM155 group, the protein levels of LC-3 and caspase-3 were lower in YM155 combined with 3-MA group.</p><p><b>CONCLUSION</b>YM155 can inhibit K562 cell proliferation by inducing apoptosis and autophagy, while autophagy induction effect can enhance its cytotoxic effect.</p>

Time rhythm of homoharringtonine inducing K562 cell apoptosis and its mechanism / 中国实验血液学杂志

This study was aimed to explore the change of K562 cell apoptosis at different time point after homoharringtonine (HHT) treatment and its mechanism. After treatment of K562 cells with 10 ng/ml HHT, the cell viability was tested with MTT assay; the expression of caspase-3 was detected with Western blot; the BCL-2 expression was analyzed with flow cytometry; the autophagosome was observed by electron microscopy. The results showed that the viability of K562 cells reduced gradually from day 1 to day 5 and ascended from day 6 to day 8 after HHT treatment. At the same time, the cleaved caspase-3 expression level of K562 cells increased gradually from day 1 to day 7, but reduced at the day 8 (P < 0.05). From day 1 to day 8 after HHT treatment, the BCL-2 expression level declined firstly and then went up (P < 0.05). Autophagosome was also seen remarkably at day 8 after HHT treatment. It is concluded that the apoptosis level of K562 cells after being treated with HHT enhances firstly and then declines , which may be associated with higher autophagy level in the late stage of HHT treatment.

Expression of Btk and NFκB in acute myeloid leukemia cells and its significance / 中国实验血液学杂志

This study was purposed to investigate the expression of Btk and NFκB in acute myeloid leukemia (AML) cells and its significance. Bone marrow mononuclear cell specimens were taken from 14 AML patients who were in new diagnosis and complete remission respectively, the expressions of Btk and NFκB at mRNA and protein levels were detected by RT-PCR and Western blot, respectively. The results showed that Btk and NFκB expressed in all the samples at RNA and protein levels. At protein level, Btk and NFκB expressions were higher in the cells from newly diagnosed AML patients than that in the cells from patients in complete remission stage (P < 0.05). It is concluded that Btk and NFκB may play an important role in the development and progression of AML, they may be used as potential therapeutic targets of AML and used in predicting the prognosis.

Effect of homoharringtonine on expression of NF-κB and BCL-2 proteins in K562 cells / 中国实验血液学杂志

This study was aimed to investigate the effect of homoharringtonine (HHT) on K562 cell proliferation, apoptosis and expression of BCL-2 and NF-κB proteins. The cells proliferation was assayed with MTT method, the cell apoptosis, cell cycle and BCL-2 expression were analyzed with flow cytometry, NF-κB protein expression was detected with Western blot. The results showed that HHT concentration-dependently inhibited proliferation of K562 cells, the IC50 at 48 h was 43.89 ng/ml. Treated with HHT 10 ng/ml for 48 h, K562 cell apoptosis significantly increased, cell cycle was blocked at G0/G1, the expression level of BCL-2 and NF-κB proteins was lower than that in control group (P < 0.05). It is concluded that HHT may inhibit the proliferation of K562 cells, and down-regulating expression levels of BCL-2 and NF-κB may be one of its anti-CML mechanisms.

Effect of PCI-32765 and bortezomib on proliferation and apoptosis of B-cell tumor cell lines and its mechanisms / 中国实验血液学杂志

This study was aimed to investigate the effect of Btk inhibitor PCI-32765 and the proteasome inhibitor bortezomib on Raji and Ramos cell proliferation, apoptosis, and its mechanisms. Raji and Ramos cells were treated with PCI-32765 and bortezomib alone and/or their combination. The cell proliferation and apoptosis were detected by CCK-8 and flow cytometry respectively, the expression level of Btk, NFκB, c-IAP1, Bcl-xL and caspase-3 protein were measured by Western blot. The results indicated that: (1) after Raji and Ramos cells were treated with PCI-32765 (0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 µmol/L) alone and bortezomib (10, 20, 30, 40, 50, 60, 80 nmol/L) alone and their combination for 48 h, the cell proliferation and vitality were inhibited in a dose-dependent manner and both had synergistic effect; (2) Raji and Ramos cells were treated with PCI-32765 (2.0 µmol/L) and bortezomib (20 nmol/L) alone and their combination for 8, 12, 24, 36, 48 and 72 h, the cell proliferation and vitality were inhibited in a time-dependent manner, the two drugs displayed a synergistic effects; (3) the Raji and Ramos cells were treated with PCI-32765 (2.0 µmol/L) and bortezomib (20 nmol/L) alone and their combination for 48 h, all these treatments could induce significant apoptosis of Raji and Ramos cells.In Raji cell experiment, the cell apoptosis rate in the control group, PCI-32765 group, bortezomib group and PCI-32765 and bortezomib combination group were 10.34 ± 0.53%, 24.26 ± 0.91%, 43.66 ± 1.08% and 74.06 ± 0.72% respectively, and the differences was statistically significant among the different groups (P < 0.05). In Ramos cell experiment, the cell apoptosis rate in the control group, PCI-32765 group, bortezomib group and PCI-32765 and bortezomib combination group are 15.16 ± 1.49%, 71.36 ± 0.82%, 75.32 ± 2.36% and 84.30 ± 0.91% respectively, the differences was statistically significant among the different groups (P < 0.05); (4) PCI-32765 and bortezomib could inhibit the expression level of intracellular Btk, NFκB, Bcl-xl and c-IAP1 proteins, but up-regulate the expression level of caspase-3. It is concluded that PCI-32765 and bortezomib can synergistically inhibit the proliferation and induce apoptosis of Raji and Ramos cells, the mechanism may be associated with inhibition of Btk and NFκB activity, down-regulation of anti-apoptotic proteins expression, such as Bcl-xl and c-IAP1, and increase of caspase-3 expression.

Effects of interferon-α combined with homoharringtonine on K562 cell proliferation and β-catenin expression / 中国实验血液学杂志

The study was aimed to investigate the synergistically effect of interferon-α (IFN-α) and homoharringtonine (HHT) on the proliferation, apoptosis, cell cycle of K562 cells and the expression of β-catenin. The proliferation, apoptosis, cell cycle and β-catenin mRNA expression of K562 cells treated with IFN-α and/or HHT were assayed with MTT, flow cytometry or RT-PCR respectively. The results showed that HHT alone, but not IFN-α alone, displayed a proliferation inhibition, apoptosis induction, G(0)/G(1) phase block and down-regulation of β-catenin expression in K562 cells with concentration- and time-dependent manners. The expression level of β-catenin mRNA after being treated with HHT was 0.5576 ± 0.0373, which were lower than that in control group (0.9369 ± 0.0142). The down-regulation of β-catenin expression in group of IFN-α combined with HHT was higher significantly than that in HHT group (0.3737 ± 0.0529 vs 0.5576 ± 0.0373, P < 0.05). Otherwise, HHT combined with IFN-α did not demonstrate obvious toxicologic effect on bone marrow mononuclear cells. It is concluded that IFN-α combined with HHT can enhance the cytotoxic effect of HHT on K562 cells, which may be associated with down-regulation of β-catenin expression.

Influence of celecoxib combined with IFN-alpha on proliferation, apoptosis, cell cycle and CD117 expression of K562 cells / 中国实验血液学杂志

The aim of this study was to investigate the effects of Celecoxib on the proliferation, apoptosis, cell cycle and CD117 expression of K562 cells, and to explore its synergistic effect with IFN-alpha. K562 cells were treated with IFN-alpha, Celecoxib and combination of Celecoxib with IFN-alpha at different concentrations. The inhibitory effect of Celecoxib and IFN-alpha on cell proliferation was detected with MTT assay, the cell apoptosis, cell cycle and CD117 expression were determined by morphology observation and flow cytometry. The results showed that the Celecoxib inhibited proliferation of K562 cells in concentration-dependent manner (r=-0.91). After culture of K562 cells for 72 hours, the rates of K562 cell proliferation in control group, IFN-alpha group, Celecoxib group and IFN-alpha-combined Celecoxib group were (96.1+/-0.5)%, (90.2+/-0.4)%, (57.2+/-0.9)% and (21.9+/-0.3)% respectively. The cell apoptosis rates in 4 groups were (5.5+/-0.8)%, (6.3+/-0.6)%, (26.4+/-3.9)% and (57.3+/-4.5)% respectively. The CD117 expression rates in 4 groups were 54.7%, 10.5%, 36.3% and 7.3% respectively. Combination of Celecoxib with IFN-alpha might block K562 cells in G0/G1 phase. In conclusion, Celecoxib and IFN-alpha both may inhibit K562 cell proliferation, induce apoptosis, reduce CD117 expression and produce G0/G1 phase block to various degree and the two drugs have a synergistic effect.

Prolonged chronic phase in chronic myelogenous leukemia after homoharringtonine therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Homoharringtonine (HHT) is effective in treating late stage chronic myelogenous leukaemia (CML), but little is known about long term maintenance during complete cytogenetic response. Long term efficacy and toxicity profiles of low dose HHT were evaluated in this study.</p><p><b>METHODS</b>One hundred and six patients with CML received 1.5 mg/m(2) of HHT alone by continuous daily infusion for seven to nine days every four weeks. Of 79 patients in the control group, 31 were treated with interferon alpha (IFN-alpha) and 48 with hydroxycarbamide. For 17 patients who failed to achieve cytogenetic response within 12 months' treatment of IFN-alpha, HHT was administered. Quantitative RT-PCR was used to detect the BCR-ABL mRNA expression in 36 Philadelphia positive CML patients enrolled after 2007. Haematological and cytogenetic responses were evaluated in all patients at the 12th month of follow-up. Long term efficacy was assessed in a follow-up with a median time of 54 months (12 months-98 months).</p><p><b>RESULTS</b>After 12 months of therapy, cytogenetic response rate of the HHT, IFN-alpha and hydroxycarbamide groups were 39/106, 14/31 and 3/48, and corresponding molecular cytogenetic response rates 6/18, 3/8 and 0. Of the 17 patients who received HHT as salvage treatment, 6 achieved cytogenetic response (3 major). At the 48 months' follow-up, cytogenetic response was maintained in 32/39 patients treated with HHT. Patients who had cytogenetic response in HHT group or treated with IFN-alpha also showed longer median chronic durations, which were 45 months (12 months-98 months) and 49 months (12 months-92 months) respectively, indicating a longer survival time.</p><p><b>CONCLUSIONS</b>Low dose HHT alone showed considerable short term and long term efficacy in the treatment of late stage CML. It may also be a good choice for patients who have failed imatinib, IFN-alpha treatment or haematopoietic stem cell transplantation or cannot afford these treatments.</p>