Synergistic Antitumor Effect of Everolimus Combined with Gemcitabine on Diffuse Large B-Cell Lymphoma / 中国实验血液学杂志

OBJECTIVE@#To investigate the effects of mTOR inhibitors everolimus (EVE) and gemcitabine (GEM) on the proliferation, apoptosis and cell cycle of diffuse large B-cell lymphoma (DLBCL) cell line U2932, and further explore the molecular mechanisms, so as to provide new ideas and experimental basis for the clinical treatment of DLBCL.@*METHODS@#The effect of EVE and GEM on the proliferation of U2932 cells was detected by CCK-8 assay, the IC50 of the two drugs was calculated, and the combination index (CI=) of the two drugs was calculated by CompuSyn software. The effect of EVE and GEM on apoptosis of U2932 cells was detected by flow cytometry with AnnexinV-FITC/PI staining. Flow cytometry with propidium iodide (PI) staining was used to detect the effect of EVE and GEM on the cell cycle of U2932 cells. Western blot assay was used to detect the effects of EVE and GEM on the channel proteins p-mTOR and p-4EBP1, the anti-apoptotic proteins MCL-1 and Survivin, and the cell cycle protein Cyclin D1.@*RESULTS@#Both EVE and GEM could significantly inhitbit the proliferation of U2932 cells in a time- and dose-dependent manner (r=0.465, 0.848; 0.555, 0.796). According to the calculation of CompuSyn software, EVE combined with GEM inhibited the proliferation of U2932 cells at 24, 48 and 72 h with CI=<1, which had a synergistic effect. After treated U2932 cells with 10 nmol/L EVE, 250 nmol/L GEM alone and in combination for 48 h, both EVE and GEM induced apoptosis, and the difference was statistically significant compared with the control group (P<0.05). The apoptosis rate was significantly enhanced after EVE in combination with GEM compared with single-agent (P<0.05). Both EVE and GEM alone and in combination significantly increased the proportion of cells in G1 phase compared with the control group (P<0.05). The proportion of cells in G1 phase was significantly increased when the two drugs were combined (P<0.05). The expression of p-mTOR and effector protein p-4EBP1 was significantly downregulated in the EVE combined with GEM group, the expression of anti-apoptotic proteins MCL-1, Survivin and cell cycle protein cyclin D1 was downregulated too (P<0.05).@*CONCLUSION@#EVE combined with GEM can synergistically inhibit the proliferation of U2932 cells, and the mechanism may be that they can synergistically induce apoptosis by downregulating the expression of MCL-1 and Survivin proteins and block the cell cycle progression by downregulating the expression of Cyclin D1.

Effect of Curcumin on Apoptosis of Acute T-Lymphoblastic Leukemia Cells induced by UMI-77 and Its Related Mechanism / 中国实验血液学杂志

AbstractObjective: To explore the effect and mechanism of curcumin on human T-cell acute lymphoblastic leukemia (T-ALL) cell apoptosis induced by Mcl-1 small molecule inhibitors UMI-77.@*METHODS@#T-ALL cell line Molt-4 was cultured, and the cells were treated with different concentrations of curcumin and Mcl-1 small molecule inhibitor UMI-77 for 24 h. The MTT method was used to detect the cell survival rate after different treatment; According to the results of curcumin and UMI-77, the experimental settings were divided into control group, curcumin group (20 μmol/L curcumin treated cells), UMI-77 group (15 μmol/L Mcl-1 small molecule inhibitor UMI-77 treated cells) and curcumin+ UMI-77 group (20 μmol/L curcumin and 15 μmol/L Mcl-1 small molecule inhibitor UMI-77 treated cells), MTT method was used to detect cell proliferation inhibition rate, Annexin V-FITC/PI double staining method and TUNEL staining were used to detect cell apoptosis, DCFH-DA probe was used to detect cell reactive oxygen species, JC-1 fluorescent probe was used to detect mitochondrial membrane potential, Western blot was used to detect the expression levels of apoptosis-related proteins and Notch1 signaling pathway-related proteins.@*RESULTS@#After the treatment of Molt-4 cells with different concentrations of curcumin and Mcl-1 small molecule inhibitor UMI-77, the cell survival rate was decreased (P<0.05); Compared with the control group, the cell proliferation inhibition rate of the curcumin group and the UMI-77 group were increased, the apoptosis rate of cell was increased, the level of ROS was increased, the protein expression of Bax, Caspase-3 and Caspase-9 in the cells were all increased, and the protein expression of Bcl-2 was reduced (P<0.05); Compared with the curcumin group or UMI-77 group, the cell proliferation inhibition rate and apoptosis rate of the curcumin+UMI-77 group were further increased, and the level of ROS was increased. At the same time, the protein expression of Bax, Caspase-3 and Caspase-9 in the cells were all increased, the protein expression of Bcl-2 was reduced (P<0.05); In addition, the mitochondrial membrane potential of the cells after curcumin treatment was decreased, and the proteins expression of Notch1 and HES1 were reduced (P<0.05).@*CONCLUSION@#Curcumin can enhance the apoptosis of T-ALL cells induced by Mcl-1 small molecule inhibitor UMI-77 by reducing the mitochondrial membrane potential, the mechanism may be related to the inhibition of Notch1 signaling pathway.

Downregulation of MCL-1 by Diallyl Disulfide Induces G/M Arrest in Human Leukemia K562 Cells and Its Mechanism / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the inducing effect of down-regulation of MCL-1 by diallyl disulfide(DADS) on the G/M arrest of human leukemia K562 cells and its mechanisms.</p><p><b>METHODS</b>CCK-8 was used to detect the effect of DADS on proliferation of K562 cells, flow cytometry was employed to observe the effect of cycle arrest by DADS and RNAi silencing MCL-1 gene in K562 cells. The expressions of MCL-1, PCNA and CDK1 in K562 cells treated with DADS were detected by Western blot. The amphigamy of MCL-1 with PCNA and CDK1 was detected by Coimmunoprecipitation.</p><p><b>RESULTS</b>CCK-8 detection showed that the inhibition rates of K562 cells treated with 15, 30, 60, 120, 240 µmol/L DADS were 32.48%, 59.34%, 66.42%, 77.06%, 81.05% respectively (P<0.05). Flow cytometry analysis revealed that the perecentages of G/M cells were increased to 18.6% and 34.4%, 17.5% and 28.5%, respectively at 24 and 48 h after treating K562 cells with 60 and 120 µmol/L DADS (P<0.05). And the perecentage of G/M cells of silencing MCL-1 was significantly increased (P<0.05). Silencing effects of MCL-1+DADS on the cells were enhanced more significantly as compared with DADS or MCL-1 alone (P<0.05). Western blot exhibited that DADS could markedly downregulate the expression of MCL-1, PCNA and CDK1(P<0.05). Coimmunoprecipitation revealed that MCL-1 bound with PCNA and CDK1, then forming heterodimers, which were downregulated respectively more significantly than that in the control group after treating K562 cells with DADS for 8 h (P<0.05).</p><p><b>CONCLUSION</b>DADS can inhibit the K562 cell proliferation and induce them arrest G/M through downregulation of MCL-1, then decreasing the expression of PCNA and CDK1 in hunan leukemia K562 cells. Moreover, silencing MCL-1 can enhance the effect of DADS.</p>

Mcl-1 as a potential therapeutic target for human hepatocelluar carcinoma / 华中科技大学学报（医学）（英德文版）

Hepatocellular carcinoma (HCC) is a major cause of cancer-related mortality in part due to its high resistance to chemotherapeutic drugs. The anti-apoptotic Mcl-1 expression has been reported as a resistance factor in various types of tumors. Here, we investigated the expression of Mcl-1 in hepatoma cells and HCC tissues and its relationship with p53, and analyzed the possibility of the gene as a molecular target for HCC therapy. HCC specimens of 30 patients were examined by immunohistochemistry for Mcl-1 and p53 expression. Mcl-1 expression in hepatoma cell lines was measured by RT-PCR and Western blotting. The suppression of Mcl-1 by RNA interference or specific phosphatidylinositol-3 kinase (PI3K) inhibitor, LY294002, was evaluated as monotherapy, and it was combined with mitomycin C (MMC) in treating hepatoma cell line HepG2. Cell viability and apoptosis were assessed by MTT and FACS analysis. Finally, changes of Mcl-1 or p53 expression in various hepatoma cell lines were examined after transfection with Mcl-1 siRNA, the Mcl-1 expression plasmid, or the wide-type p53 expression plasmid, respectively. Mcl-1 protein was remarkably enhanced in HCC tissues as compared with adjacent non-tumor liver tissues. In addition, Mcl-1 was prominently expressed in HepG2 and Hep3B cells, weakly in SMMC7721 cells, and not in L02 cells. P53 protein was also overexpressed in HCC tissues and there was a significant correlation between the expression of p53 and Mcl-1. Silencing Mcl-1 by RNAi or LY294002 downregulated Mcl-1 expression and led to decreased cell viability and increased apoptosis. Combination of MMC and Mcl-1 RNAi or LY294002 exhibited a significant chemosensitizing effect. The expression of p53 was not influenced by Mcl-1 siRNA in HepG2 cells or transfection with the Mcl-1 expression plasmid in L02 cells. Furthermore, the expression of Mcl-1 in Hep3B cells was also not significantly changed after transfection with the wild-type p53 expression plasmid. It is concluded that Mcl-1 is overexpressed in HCC tissues. The mechanisms by which silencing Mcl-1 sensitizes hepatoma cells towards chemotherapy may be not attributed to the upregulated expression of p53 but the dysfunction of p53 through Mcl-1/p53 interaction. Mcl-1 may be a potential target of gene therapy for HCC.

Isochamaejasmin induces apoptosis in leukemia cells through inhibiting Bcl-2 family proteins / 中国天然药物

The biflavonoid isochamaejasmin is mainly distributed in the root of Stellera chamaejasme L. (Thymelaeaceae) that is used in traditional Chinese medicine (TCM) to treat tumors, tuberculosis, and psoriasis. Herein, isochamaejasmin was found to show similar bioactivity against Bcl-2 family proteins to the reference Bcl-2 ligand (-)-gossypol through 3D similarity search. It selectively bound to Bcl-xl and Mcl-1 with Ki values being 1.93 ± 0.13 μmol·L(-1) and 9.98 ± 0.21 μmol·L(-1), respectively. In addition, isochamaejasmin showed slight growth inhibitory activity against HL-60 with IC50 value being 50.40 ± 1.21 μmol·L(-1) and moderate growth inhibitory activity against K562 cells with IC50 value being 24.51 ± 1.62 μmol·L(-1). Furthermore, isochamaejasmin induced apoptosis of K562 cells by increasing the intracellular expression levels of proteins of the cleavage of caspase-9, caspase-3, and PARP which involved in the Bcl-2-induced apoptosis pathway. These results indicated that isochamaejasmin induces apoptosis in leukemia cells by inhibiting the activity of Bcl-2 family proteins, providing evidence for further studying the underlying anti-cancer mechanism of S. chamaejasme L.

Expression and significance of miR-125a and Mcl-1 in intestinal tissue after massive small bowel resection in rat / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the expression and significance of miR-125a and anti-apoptotic protein Mcl-1 in intestinal tissue after massive small bowel resection in intestinal adaptation.</p><p><b>METHODS</b>Sprague-Dawley rats (54 male rats, 8-week old) were divided into 3 groups randomly, including two control groups. Rats in the experiment group were subjected to 70% massive small bowel resection. Rats in the resection group underwent simple intestinal resection and anastomosis. Rats in the control group underwent laparotomy alone. A 5 cm intestine approximately 1 cm distal to the anastomosis was harvested a week after operation. Expression of Mcl-1 was assessed by immunohistochemistry and real-time PCR was used to detect the expression of miR-125a in intestinal tissue.</p><p><b>RESULTS</b>The positive expression of Mcl-1 in the experiment group was 18.8%(3/16), significantly lower than that in the control group(76.5%, 13/17) and the resection group (83.33%, 15/18)(both P<0.01). The expression of miR-125a in the experiment group was 1.92, significantly higher than that in the control group (1.01) and the resection group (1.05)(both P<0.01).</p><p><b>CONCLUSION</b>miR-125a and anti-apoptotic protein Mcl-1 may play an important role in intestinal adaptation process and they may regulate each other through a certain pathway.</p>

Study on impact of ethanol extracts from Sedum sarmentosum in inhibiting STAT-3 signaling and inducing apoptosis of human hepatocellular carcinoma cell line HepG2 / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the impact of ethanol extracts from Sedum sarmentosum (ESB) on STAT-3 signaling and its probable molecular mechanism in inducing apoptosis.</p><p><b>METHOD</b>MTT assay was used to detect the impact of ESB on HepG2 cell proliferation. FITC-Annexin V-FITC /PI double-labeling were used to investigate the impact on hepatoma carcinoma cell apoptosis. Western blot analysis was used to test the expression levels of cell apoptosis-related proteins Caspase-3, Caspase-9, PARP, P-STAT-3 (Tyr705) , STAT-3, Bcl-2, Mcl-1.</p><p><b>RESULT</b>ESB could notably inhibit proliferation of HepG2 cells, and induce HepG2 cell apoptosis, with the dose-dependent inhibitory effect. In addition, ESB could inhibit STAT-3 signaling, down-regulate Mcl-1 and Bcl-2 expressions, and induce degradation/activation of apoptosis-related proteins Caspase-3 and Caspase-9 and PARP degradation in a dose-dependent manner.</p><p><b>CONCLUSION</b>ESB inhibits HepG2 cell proliferation and induces apoptosis by inhibiting STAT-3 signaling and Mcl-1 and Bcl-2 expressions.</p>

Expressions of farnesoid X receptor and myeloid cell leukemia sequence 1 protein are associated with poor prognosis in patients with gallbladder cancer / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Farnesoid X receptor (FXR) regulates tumorigenesis, but its clinical significance in gallbladder cancer (GBC) remains unclear. This study investigated its clinical and prognostic significance in GBC patients, as well as its association with the anti-apoptotic protein, myeloid cell leukemia sequence 1 (MCL1) protein.</p><p><b>METHODS</b>FXR and MCL1 expression in 42 primary GBC and 15 normal gallbladder tissues were analyzed by immunohistochemistry. The patients and samples were collected from Ren Ji Hospital from January 2005 to December 2010. Their association with clinicopathologic factors and prognosis, as well as the correlation between FXR and MCL1 protein expression were analyzed by statistical analyses.</p><p><b>RESULTS</b>Compared with normal gallbladder tissues, FXR expression was decreased and MCL1 expression was increased in GBC, during progression of tumor node metastasis (TNM) stage. The Kaplan-Meier survival analysis showed that FXR low-expression and MCL1 over-expression were significantly associated with overall poor survival. Furthermore, multivariate analysis showed that FXR and MCL1 are both prognostic factors for GBC patients. FXR low-expression was significantly correlated with MCL1 over-expression.</p><p><b>CONCLUSION</b>FXR might be a new molecular marker to predict the prognosis of patients with GBC and a novel therapeutic target.</p>

Effect of downregulation of Tiam1 by siRNA on esophageal squamous cell carcinoma EC9706 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the effect of downregulation of Tiam1 by siRNA on the esophageal squamous cell carcinoma (ESCC) EC9706 cells, and provide theoretical basis for gene therapy of ESCC using Tiam1 as a molecular target.</p><p><b>METHODS</b>Tiam1 siRNA was transfected into EC9706 cells, and expression changes of Tiam1 mRNA and protein after transfection were detected by quantitative real-time PCR and Western blotting. Cell proliferation was analyzed using CCK-8 kit. Cell cycle and apoptosis of the EC9706 cells were assessed by flow cytometry. Cell cycle-related proteins and cell apoptosis-associated proteins were analyzed by Western blotting.</p><p><b>RESULTS</b>Compared with the untreated group and control siRNA group, the relative expression levels of Tiam1 mRNA (1.00 and 0.11 ± 0.02) were not significantly different (P > 0.05). The relative expression levels of Tiam1 mRNA in the Tiam1 siRNA group at 24, 48 and 72 h after transfection were 0.30 ± 0.04, 0.09 ± 0.01 and 0.09 ± 0.006, respectively, significantly lower than that of the untreated group (P < 0.05 for all). The expression level of Tiam1 protein at 24 h after Tiam1 siRNA transfection in the EC9706 cells was 0.11 ± 0.02, significantly lower than that in the un-treated group (0.44 ± 0.05) and control siRNA group (0.44 ± 0.04, P < 0.05 for all). The percentages of G0/G1 cells in the Tiam1 siRNA group, untreated group and control siRNA group were (54.48 ± 2.14)%, (40.69 ± 1.85)% and (41.78 ± 1.31)%, respectively (P < 0.01). The percentages of S phase cells in the Tiam1 siRNA group, untreated group and control siRNA group were (27.18 ± 1.65)%, (32.32 ± 1.15)% and (30.35 ± 1.09)%, respectively (P < 0.01). The expression levels of cyclin D1 protein in the untreated group, control siRNA group and Tiam1 siRNA group were 0.43 ± 0.02, 0.41 ± 0.01 and 0.11 ± 0.02, respectively (P < 0.05). The expression levels of p27 protein in the untreated group, control siRNA group and Tiam1 siRNA group were 0.10 ± 0.01, 0.09 ± 0.02 and 0.20 ± 0.02, respectively (P < 0.05). The ratios of early apoptotic cells in the untreated group, control siRNA group and Tiam1 siRNA group were (10 ± 0.9)%, (10 ± 0.5)% and (27 ± 0.7)%, respectively (P < 0.01). The expression levels of Mcl-1 protein in EC9706 cells of untreated group, control siRNA group and Tiam1 siRNA group were 0.47 ± 0.12, 0.48 ± 0.13 and 0.16 ± 0.02, respectively (P < 0.05). The expression levels of Bcl-2 protein in EC9706 cells of the untreated group, control siRNA group and Tiam1 siRNA group were 0.49 ± 0.08, 0.50 ± 0.05 and 0.04 ± 0.03, respectively (P < 0.05). The caspase-3 activities in the untreated group, control siRNA group and Tiam1 siRNA group were 2.3 ± 0.09, 2.3 ± 0.10 and 16.0 ± 1.50, respectively; and that of caspase-9 were 2.3 ± 0.08, 2.3 ± 0.11 and 14.5 ± 0.9, respectively (P < 0.05 for all).</p><p><b>CONCLUSIONS</b>Tiam1 siRNA can significantly inhibit the proliferation of esophageal cancer EC9706 cells, induce cell cycle arrest and cell apoptosis. These effects are related to the regulation of the expressions of cell cycle-related genes (cyclin D1 and p27) and cell apoptosis-related genes (Mcl-1, Bcl-1, caspase-3 and caspase-9) by Tiam1 siRNA.</p>

Knockdown of Bcl-xL Enhances Growth-Inhibiting and Apoptosis-Inducing Effects of Resveratrol and Clofarabine in Malignant Mesothelioma H-2452 Cells

Mcl-1 and Bcl-xL, key anti-apoptotic proteins of the Bcl-2 family, have attracted attention as important molecules in the cell survival and drug resistance. In this study, we investigated whether inhibition of Bcl-xL influences cell growth and apoptosis against simultaneous treatment of resveratrol and clofarabine in the human malignant mesothelioma H-2452 cells. Resveratrol and clofarabine decreased Mcl-1 protein levels but had little effect on Bcl-xL levels. In the presence of two compounds, any detectable change in the Mcl-1 mRNA levels was not observed in RT-PCR analysis, whereas pretreatment with the proteasome inhibitor MG132 led to its accumulation to levels far above basal levels. The knockdown of Bcl-xL inhibited cell proliferation with cell accumulation at G2/M phase and the appearance of sub-G0/G1 peak in DNA flow cytometric assay. The suppression of cell growth was accompanied by an increase in the caspase-3/7 activity with the resultant cleavages of procaspase-3 and its substrate poly (ADP-ribose) polymerase, and increased percentage of apoptotic propensities in annexin V binding assay. Collectively, our data represent that the efficacy of resveratrol and clofarabine for apoptosis induction was substantially enhanced by Bcl-xL-lowering strategy in which the simultaneous targeting of Mcl-1 and Bcl-xL could be a more effective strategy for treating malignant mesothelioma.

Homoharringtonine combined arsenic trioxide induced apoptosis in human multiple myeloma cell line RPMI 8226: an experimental research / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To clarify the effects and mechanisms of homoharringtonine (HHT) monomer therapy or combination therapy with arsenic trioxide (ATO) on human multiple myeloma (MM) cell line RPMI 8226 in in vitro researches.</p><p><b>METHODS</b>Effects of HHT, ATO, and HHT combined ATO on the growth of MM cell line RPMI 8226 were detected using MTT assay. The morphological changes of cell apoptosis were detected by Hoechst staining. The early apoptosis rate was detected using flow cytometry. Expressions of Caspase-3, Caspase-9, poly-ADP-ribose polymerase (PARP), Bcl-2, Mcl-1, Bcl-xl, and AKT protein were detected by Western blot.</p><p><b>RESULTS</b>HHT and ATO inhibited the proliferation of RPM1 8226 cell line in a time- and dose-dependent manner (P < 0.05). Synergistic effects was shown in the combination group (Cl < 1). HHT and ATO induced the apoptosis of RPMI 8226 in a dose-dependent manner with typical morphological changes of apoptosis and higher early stage apoptosis rate. The enhancement in apoptotic induction was seen when two agents were combined. HHT activated expressions of Caspase-3 and PARP in a dose dependent manner at 24 h. HHT at 40 ng/mL and ATO at 8.5 micromol/L could significantly activate expressions of Caspase-3 and Caspase-9, and down-regulate expressions of anti-apoptotic proteins Bcl-xl and Mcl-1. In addition, the combination therapy of HHT at 40 ng/mL and ATO at 8.5 micromol/L inhibited phosphorylation of AKT in a time-dependent manner.</p><p><b>CONCLUSION</b>HTT, ATO, and combination therapy of HHT and ATO induced the apoptosis of RPMI 8226 cell line possibly through activating Caspase pathways, regulating expressions of Bcl-2 families, and inhibiting phosphorylation of AKT.</p>

TcpC induces apoptosis of human vascular endothelial cells and its mechanisms / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of TcpC on human umbilical vascular endothelial cells (HUVECs) and its mechanisms.</p><p><b>METHODS</b>HUVECs were co-cultured with TcpC secreting wild-type E. coli strain CFT073 (TcpC(wt)) or tcpc gene-deleted CFT073 mutant strain (TcpC(mut)) in transwell system,respectively. Apoptosis of HUVECs was analyzed by Annexin-V/PI double staining. Mitochondrial membrane depolarization was detected by JC-1 staining. Expression of apoptosis-related proteins in HUVECs was determined by Western blot.</p><p><b>RESULTS</b>HUVECs showed morphological changes after co-cultured with TcpC(wt) for 24 h: the cells became detached and cell debris increased,and cell number was also decreased when compared to HUVECs co-cultured with TcpC(mut). The apoptosis of HUVEC cells co-cultured with TcpC(wt) for 24 h significantly increased,compared to that of control group and TcpC(mut) group (60.1% 9.7% compared with 9.0% 1.3% and 16.9% 0.4%,respectively, P<0.05); meanwhile the mitochondrial depolarization of HUVECs co-cultured with TcpC(wt) was significantly increased,compared to that in control and TcpC(mut) groups (64.5% 0.9% compared with 14.5% 2.1% and 15.6% 3.3%, respectively,P<0.05). Cleavage of PARP and inhibition of Mcl-1 and XIAP expression were seen in HUVECs co-cultured with TcpC(wt),but not in groups of control and TcpC(mut).</p><p><b>CONCLUSION</b>TcpC secreted from CFT073 can induce apoptosis of HUVECs through mitochondrial pathway, in which PARP is cleaved and Mcl-1 and XIAP expressions are inhibited.</p>

MiR-106a targets Mcl-1 to suppress cisplatin resistance of ovarian cancer A2780 cells / 华中科技大学学报（医学）（英德文版）

Resistance to chemotherapy is a major obstacle for the effective treatment of advanced ovarian cancer. The mechanism of chemoresistance is still poorly understood. Recently, more and more evidence showed microRNAs (miRNAs) modulated many key molecules and pathways involved in chemotherapy. microRNA-106a (miR-106a) has been implicated in many cancers, but its role in ovarian cancer and drug resistance still remains unexplored. This study was to investigate whether miR-106a mediated resistance of the ovarian cancer cell line A2780 to the chemotherapeutic agent cisplatin (DDP). The different levels of miR-106a in A2780 cells and their resistant variant A2780/DDP cells were identified by using real-time PCR. MTT assay and flow cytometry were used to analyze the effect of miR-106a on cisplatin resistance of these paired cells. Real-time PCR, Western blotting and luciferase reporter assay were applied to explore whether Mcl-1 was a target of miR-106a. As compared to A2780 cells, the expression of miR-106a was down-regulated in the cisplatin resistant cell line A2780/DDP. Moreover, knockdown of miR-106a dramatically decreased antiproliferative effects and apoptosis induced by cisplatin in A2780 cells, while overexpression of miR-106a significantly increased antiproliferative effects and apoptosis induced by cisplatin in A2780/DDP cells. Furthermore, miR-106a inhibited cell survival and cisplatin resistance through downregulating the expression of Mcl-1. Mcl-1 was a direct target of miR-106a. These results suggest that miR-106a may provide a novel mechanism for understanding cisplatin resistance in ovarian cancer by modulating Mcl-1.

Relationship between the expression level of miR-29c and biological behavior of gastric cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the function and clinicopathological significance of RNA-29c (miR-29c) in the carcinogenesis and development of gastric cancer.</p><p><b>METHODS</b>MicroRNA microarray was applied to assess the miRNAs expression profile of gastric cancer. Quantitative real-time PCR was used to detect the expression of miR-29c in 64 cases of gastric cancer tissues and corresponding normal gastric epithelium, as well as cell lines GES-1, BGC-823 and SGC-7901 cells. MTT assay and flow cytometry were applied to detect the effects of forced expression of miR-29c in gastric cancer BGC-823 cells including cell proliferation, apoptosis, cell cycle and drug sensitivity. Quantitative real-time PCR, Western blot and luciferase reporter assay were used to explore the targeted relationship between miR-29c and myeloid cell leukemia-1 (Mcl-1).</p><p><b>RESULTS</b>Compared with normal gastric epithelium, seven microRNAs (miR-374b*, miRPlus-E1212, miR-338-5p, miR-297, miR-21, miR-135b, miR-18a) were significantly up-regulated more than 2-folds, and nine microRNAs (miR-29b-2*, miR-1260, miRPlus-E1241, miR-S1-5p, miR-148a, miR-29c, miR-647, miR-196b*, ebv-miR-BART5) were significantly down-reguated in gastric cancer tissues. The average expression level of miR-29c in gastric cancer tissues was 0.70 ± 0.34 and in corresponding normal epithelium was 1.00 ± 0.06 (P < 0.05). miR-29c expression was related to tumor size, lymph node metastasis, clinical stage, Laurén classification, Borrmann classification and Ming classification (P < 0.05). The poorer differentiation degree of gastric cell lines, the lower was miR-29c expression level (P < 0.05). Overexpression of miR-29c in gastric cancer BGC-823 cells suppressed cell proliferation, stimulated cell apoptosis, induced cell cycle arrest in S phase and increased the chemotherapy sensitivity to drug docetaxel (all were P < 0.05). The average expression level of Mcl-1 mRNA in gastric cancer tissues was 3.47 ± 1.34 and corresponding epithelialium was 1.00 ± 0.20 (P < 0.05). The expression level of miR-29c was negatively related with that of Mcl-1 mRNA in gastric cancer tissues. miR-29c directly targeted to regulation of Mcl-1 expression.</p><p><b>CONCLUSIONS</b>There are special miRNA expression profile in gastric cancer. The expression of miR-29c is closely related to biological behavior of human gastric cancer. miR-29c is involved in targeted regulation of Mcl-1, and may be one of mechanisms of the carcinogenesis of gastric cancer.</p>

Inhibitory effect of 14-3-3ζ on the proliferation of HL-60 cells and HL-60/VCR cells / 中国实验血液学杂志

This study was aimed to investigate the expression and role of 14-3-3ζ in the AML cell lines: sensitive HL-60 and drug-resistant HL-60/VCR cells. Semi-quantitative RT-PCR and Western blot were respectively used to examine the expression of mdr1 mRNA and Pgp in AML cell lines to validate the results of microarray. Western blot was performed to investigate the expression of Pgp, 14-3-3ζ, and anti-apoptosis protein BCL-2, MCL-1 proteins. Immunofluorescence assay was used to detect the subcellular location of 14-3-3ζ protein in HL-60 and HL-60/VCR cells by laser scanning confocal microscopy. Transduction with siRNA was used to silence 14-3-3ζ in AML cell lines. Cell count method and flow cytometry of cell cycle were used to analyze the changes of growth of AML cells. The results found that mdr1 mRNA and Pgp did not expressed in HL-60 cells, but significantly overexpressed in HL-60/VCR cells. Except 14-3-3σ, the expression of other subtypes of 14-3-3 was higher in HL-60/VCR cells than that in HL-60 cells, especially 14-3-3ζ. The higher expression of 14-3-3ζ, BCL-2, MCL-1 protein was observed in HL-60/VCR cells than that in HL-60 cells. These results were same results from gene chip. It was also noticed that 14-3-3ζ was located in the cytoplasma and nuclei of AML cell lines, especially over-expressed in HL-60/VCR cells. Furthermore, suppression of 14-3-3ζ by RNA interference resulted in inhibition of the proliferation of AML cells with decreased protein expression of BCL-2 and MCL-1, especially in HL-60/VCR cells. It is concluded that 14-3-3ζ plays an important role in proliferation of AML cells and associates with BCL-2 and MCL-1 expression. These results suggested that development of therapy targeting 14-3-3ζ may provide novel, effective strategies for refractory and relapsed AML.

Expression of survivin in patients with acute myeloid leukemia / 中国实验血液学杂志

Objective of this study was to detect the expression of Survivin in acute myeloid leukemia (AML) and investigate the relationship of its expression levels with clinical variates and its correlations with BCL-2 ,Bcl-xL and MCL-1. The expression of Survivin, BCL-2, Bcl-xL and MCL-1 were measured by immunohistochemistry in bone marrow biopsy of 63 newly diagnosed AML patients, and the relationship between its expression level and clinical parameters (age, sex, WBC count, diagnosis, prognosis), especially fusion protein AML1/ETO was investigated. The results showed that the expression level of Survivin in newly diagnosed AML patients was higher than that of normal controls (P < 0.01), the expression levels of Survivin did not correlate with age, sex, and WBC counts of patients and so on. There was no significant difference of Survivin expression between different NCCN prognosis groups, either between patients with AML1/ETO or FLT3-ITD mutation and the other patients. Survivin positive patients were got to have lower CR rate but higher relapse rate, however that was not significant in statistics. Indeed, the cumulative survivin rate of Survivin positive patients were lower than that of Survivin negative patients (P = 0.04). Finally, positive correlation between Survivin and MCL-1 was also observed (r = 0.639, P = 0.000). It is concluded that overexpression of Survivin are closely related with occurrence and development of acute leukemia, and may be used as an indicator of prognosis evaluation. In addition, Survivin and MCL-1 may have a relationship of cooperation or interaction.

COX-2 inhibitor celecoxib can suppress the proliferation of FLT3-ITD positive acute myeloid leukemia cells with prominent down regulation of MEK/MCL-1 expression in vitro / 中国实验血液学杂志

The purpose of this study was to investigate the effects of Celecoxib on the proliferation of the FLT3-ITD positive and negative acute myeloid leukemia cells and its mechanism. The proliferation inhibition effect of Celecoxib with different doses on the FLT3-ITD positive cells MV4-11 and the FLT3-ITD negative K562 cells was detected by CCK-8 method, the cell apoptosis was determined by flow cytometry, and the MEK, Mcl-1, pAKT expression was tested by Western blot. The results showed that Celecoxib inhibited the proliferation of both MV4-11 and K562 cells, but the IC50 for MV4-11 was (29.14 ± 2.4) µmol/L, which was significantly lower than that of K562 cells (39.84 ± 1.0) µmol/L (P < 0.05); The induced apoptosis rate of Celecoxib at 20-80 µmol/L on MV4-11 was not observed, but there was apparent influence on K562 at the same concentration. Western blot showed that Celecoxib down-regulated the expression of MEK and Mcl-1 but did not change the expression of pAKT obviously on MV4-11 cells, while the expression of Mcl-1 was reduced a little, but no obvious change were found in the expression of MEK and pAKT on K562 cells. It is concluded that the Celecoxib can inhibit the proliferation of FLT3-ITD positive AML cells distinctly, and the potential mechanism may be related to the inhibition of the MEK/Mcl-1 signaling pathway.

Bufo gargarizans mcl-1 cloning and its prokaryotic recombinant protein expression / 药学学报

MCL-1 is encoded by myeloid cell leukemia-1 gene (mcl-1), which is one of the anti-apoptotic members of bcl-2 cell apoptotic gene superfamily. ChanSu is made of dorsal secretions of several Bufo species, commonly used in the prescriptions of traditional Chinese medicine for treating many diseases including cancer. To clarify if mcl-1 is expressed in the dorsal skin of B. gargarizans, the PCR (polymerase chain reaction) was performed with its dorsal skin first strand cDNA as the template and a pair of specific primers of mcl-1, and PCR products were cloned into the pGM-T vector. DNA sequencing indicated that the ORF length was 639 bp encoding 212 amino acid residues, and the homology of 44%-95% with the MCL-1 of several other animals. For the further studies on MCL-1 biological functions during the oncogenesis and preparation of its antibody, the prokaryotic expression construct of pET-28b-mcl-1 was prepared which was confirmed by DNA sequencing, and its recombinant protein expression (0.02% wet weight) in E. coli BL21 (DE3) strain was confirmed by SDS-PAGE and Western blotting.

Expression of MCL-1 and microRNA-29a in extranodal NK/T-cell lymphoma tissue / 中国实验血液学杂志

This study was aimed to explore the expression level and correlation of MCL-1 and miR-29a in extranodal NK/T-cell lymphoma (ENKTCL) tissue. Maxvision immunohistochemistry technique and real time fluorescent quantitative PCR were used to detect the expression level of MCL-1 and miR-29a in tissue of 20 patients with ENKTCL and 10 patients with proliferative lymphadenitis, respectively. The results showed that the expression of MCL-1 protein were higher in patients with ENKTCL than that in patients with proliferative lymphadenitis, but there were no significant correlation between MCL-1 overexpression and age, sex, Ann Arbor stage and International Prognostic Index (IPI), respectively. Correlation analysis indicated that there was significant negative correlation between miR-29a expression and MCL-1 expression (r = -0.59, P = 0.016). It is concluded that miR-29a may target MCL-1 gene, regulate its expression, then participate in tumorigenesis and development of ENKTCL.

Overexpression of p-Stat3 and Mcl-1, and their correlation with differentiation and apoptotic resistance in esophageal squamous cell carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To detect the expression of phosphorylated-signal transducer and activator of transcription 3 (p-Stat3) and myeloid leukemia-1 (Mcl-1) as well as their correlation, and to investigate the functional role of Stat3 and Mcl-1 in the pathogenesis of esophageal squamous cell carcinoma (ESCC).</p><p><b>METHODS</b>Stat3 activity in ESCC cells was inhibited with JAK/Stat3 inhibitors (AG490 or JSI-124). Specific siRNA was used to inhibit the Stat3 expression. Cell apoptosis was detected by flow cytometry. Expression of Mcl-1 protein was determined by Western blotting. Expression of phospho-Stat3 (Tyr705) and myeloid leukemia-1 (Mcl-1) proteins in ESCC tissues was detected by tissue microarray and immunohistochemistry. The relationship between p-Stat3 or Mcl-1 aberrant expression and clinicopatholohical features of ESCC was analyzed. The correlation of their expression was also analyzed.</p><p><b>RESULTS</b>Suppression of the Stat3 signaling activation in ESCC cells led to marked apoptosis, and dramatic reduction of Mcl-1 protein. The positive rate of phospho-Stat3 (Tyr705) expression was 45.0% in 50/111 of the ESCC tissue samples. The lower the degree of tumor differentiation, the higher the positive rate of phospho-Stat3 (Tyr705), showing a significant difference (P = 0.018). The positive rate of Mcl-1 protein expression was 72.1% (80/111), and the lower the degree of tumor differentiation was, the higher there was the positive rate of Mcl-1, with a significant difference (P = 0.026). There was a positive correlation between the expressions of p-Stat3 and Mcl-1 proteins (P = 0.012).</p><p><b>CONCLUSIONS</b>In a subset of ESCC tissues, p-Stat3 (Tyr705) and Mcl-1 are overexpressed and positively correlated with each other, and both are correlated with tumor differentiation. Persistent activation of Stat3 contributes to apoptotic resistance in ESCC cells, and may be at least partly mediated through upregulation of Mcl-1.</p>