Establishment of leukemia cell model with inducible AML1-ETO expression and its effect on fatty acid metabolism in leukemia cells / 中华血液学杂志

Objective: To investigate the effect of the AML1-ETO (AE) fusion gene on the biological function of U937 leukemia cells by establishing a leukemia cell model that induces AE fusion gene expression. Methods: The doxycycline (Dox) -dependent expression of the AE fusion gene in the U937 cell line (U937-AE) were established using a lentivirus vector system. The Cell Counting Kit 8 methods, including the PI and sidanilide induction, were used to detect cell proliferation, cell cycle-induced differentiation assays, respectively. The effect of the AE fusion gene on the biological function of U937-AE cells was preliminarily explored using transcriptome sequencing and metabonomic sequencing. Results: ①The Dox-dependent Tet-on regulatory system was successfully constructed to regulate the stable AE fusion gene expression in U937-AE cells. ②Cell proliferation slowed down and the cell proliferation rate with AE expression (3.47±0.07) was lower than AE non-expression (3.86 ± 0.05) after inducing the AE fusion gene expression for 24 h (P<0.05). The proportion of cells in the G(0)/G(1) phase in the cell cycle increased, with AE expression [ (63.45±3.10) %) ] was higher than AE non-expression [ (41.36± 9.56) %] (P<0.05). The proportion of cells expressing CD13 and CD14 decreased with the expression of AE. The AE negative group is significantly higher than the AE positive group (P<0.05). ③The enrichment analysis of the transcriptome sequencing gene set revealed significantly enriched quiescence, nuclear factor kappa-light-chain-enhancer of activated B cells, interferon-α/γ, and other inflammatory response and immune regulation signals after AE expression. ④Disorder of fatty acid metabolism of U937-AE cells occurred under the influence of AE. The concentration of the medium and short-chain fatty acid acylcarnitine metabolites decreased in cells with AE expressing, propionyl L-carnitine, wherein those with AE expression (0.46±0.13) were lower than those with AE non-expression (1.00±0.27) (P<0.05). The metabolite concentration of some long-chain fatty acid acylcarnitine increased in cells with AE expressing tetradecanoyl carnitine, wherein those with AE expression (1.26±0.01) were higher than those with AE non-expression (1.00±0.05) (P<0.05) . Conclusion: This study successfully established a leukemia cell model that can induce AE expression. The AE expression blocked the cell cycle and inhibited cell differentiation. The gene sets related to the inflammatory reactions was significantly enriched in U937-AE cells that express AE, and fatty acid metabolism was disordered.

Citotoxicidad in vitro del polipéptido antimicrobiano nisina sobre células tumorales sanguíneas / In vitro cytotoxicity of the antimicrobial polypeptide nisin on blood tumor cells

RESUMEN: Las bacteriocinas son péptidos antimicrobianos de síntesis ribosomal secretadas por bacterias. Dentro de estas destaca nisina que posee potenciales usos en terapias antibióticas, como biopreservante de alimentos y probióticos. También se ha descrito que nisina posee citotoxicidad sobre líneas celulares neoplásicas, pero existe poca información de su efecto sobre células tumorales sanguíneas. Debido al potencial uso que presenta nisina, es relevante determinar la toxicidad que presenta sobre líneas celulares tumorales del tipo sanguíneo. Para esto, se realizaron ensayos de actividad hemolítica sobre eritrocitos humanos y de toxicidad sobre células mononucleares de sangre periférica humanas, determinándose que nisina no posee efecto citotóxico sobre este tipo de células normales humanas sanguíneas. Se realizaron también, ensayos de citotoxicidad con líneas celulares tumorales (K562 y U937), con el fin de determinar dosis, tiempo de exposición y selectividad en el efecto tóxico de nisina sobre las células tumorales humanas. Estos ensayos muestran que nisina presenta actividad citotóxica sobre líneas celulares K562 y U937 a las 72 h de exposición, a una concentración de 40 µg/mL, que corresponde a 100 veces la concentración mínima inhibitoria (MIC) usada para su acción sobre bacterias. Al comparar el efecto de nisina sobre células mononucleares de sangre periférica humanas con las líneas tumorales linfoides y mieloides (K562 y U937 respectivamente), se observa un efecto selectivo de nisina sobre las células tumorales sanguíneas.

SUMMARY: Bacteriocins are antimicrobial peptides of ribosomal synthesis secreted by bacteria. Among these, nisin stands out, which has potential uses in antibiotic therapies, as a food bio preservative and probiotics. Nisin has also been reported to have cytotoxicity on neoplastic cell lines, but there is little information on its effect on blood tumor cells. Due to the potential use that nisin presents, it is relevant to determine the toxicity it presents on tumor cell lines of the blood type. For this, hemolytic activity tests were carried out on human erythrocytes and toxicity on human peripheral blood mononuclear cells, determining that nisin does not have a toxic effect on this type of normal human blood cells. Cytotoxicity tests were also carried out with tumor cell lines (K562 and U937), to determine dose, exposure time and selectivity in the toxic effect of nisin on human tumor cells. These tests show that nisin shows cytotoxic activity on K562 and U937 cell lines at 72 h of exposure, at a concentration of 40 µg / mL, which corresponds to 100 times the minimum inhibitory concentration (MIC) used for its action on bacteria. When comparing the effect of nisin on human peripheral blood mononuclear cells with lymphoid and myeloid tumor lines (K562 and U937 respectively), a selective effect of nisin on blood tumor cells is observed.

Effects of XPO1 Inhibitor KPT-8602 on Proliferation and Apoptosis in U937 cells / 中山大学学报(医学科学版)

@#【Objective】To explore the effects and the possible mechanism of KPT- 8602，a novel selective inhibitor of nuclear export protein （XPO1），on proliferation，cell cycle and apoptosis in human histiocytic lymphoma cell line U937 cells.【Methods】U937 cells were treated with different concentrations of KPT- 8602. Cell viability was assessed by CCK-8 assay. The cell cycle distribution and the apoptosis rate were analyzed by flow cytometry. The proteins expression of XPO1，p-AKT，AKT，Cleaved Caspase-3，p21 were determined by Western blot. Fluorescence microscope was used in observing the intracellular location of XPO1. 【Results】 KPT- 8602 inhibited the growth of U937 cells in a dose- dependent（P<0.001）and time- dependent manner（P<0.001），but normal PBMC were unaffected. 48 h after treatment with KPT-8602，a higher proportion of cells in G1 phase was observed（P<0.001）and the apoptosis rate increased（P=0.016）with drug concentration in U937 cells. XPO1 protein expression of U937 cells was significantly higher than normal PBMC（P=0.003）. 48 h after treatment with KPT- 8602，the protein expression of XPO1 decreased（P=0.011），p-AKT decreased（P=0.011），and Cleaved Caspase- 3 increased（P=0.009）. In addition，the protein expression of p21，the cargo protein of XPO1，increased in both the nuclei and the cytoplasm（P<0.05）after treatment with KPT- 8602. XPO1 decreased in both the nuclei and the cytoplasm under the fluorescence microscope after treatment with KPT- 8602.【Conclusion】KPT- 8602 can inhibit the proliferation of U937 cells，block the cell cycle at G1 phase，and induce cell apoptosis，which may partially be attributed to the down-regulation of XPO1 and inhibition of PI3K/AKT signaling.

Induction of Apoptosis Scutellaria baicalensis Georgi Root Extract by Inactivation of the Phosphatidyl Inositol 3-kinase/Akt Signaling Pathway in Human Leukemia U937 Cells

BACKGROUND: The roots of Scutellaria baicalensis Georgi (Labiatae) have been widely used in traditional medicine for treatment of various diseases. In this study, we investigated the effects of ethanol extracts of S. baicalensis roots (EESB) on the growth ofn human leukemia U937 cells. METHODS: The effect of EESB on cell viability was measured by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Apoptosis was determined using 4,6-diamidino-2-phenyllindile staining and flow cytometry. The effects of EESB on the expression of regulatory proteins of apoptosis and phosphatidyl inositol 3-kinase (PI3K)/Akt signaling were determined by Western blotting. Caspase activity and mitochondrial membrane potential (MMP) were measured using flow cytometric analysis.

Manumycin-induced apoptosis in U937 human myeloid leukemia cells via blocking PI3K/Akt signaling pathway / 实用医学杂志

Objective To explore the effects of manumycin on U937 cells and its mechanisms.Methods Apoptosis was detected by flow cytometry using annexin V and propidium iodide (PI) after treatment with manumycin (2 μmol/L) for different time.The reactive oxygen species (ROS) was detected by flow cytometry using Reactive Oxygen Species Assay Kit.The expressions of PI3K,P-Akt and Akt were detected by Western blotting.Results Compared with the 0 h treatment,manumycin treatment resulted in apoptosis (P ＜ 0.05) and ROS generation (P ＜ 0.05) gradually in U937 cell lines.Furthermore,manumycin also inhibited the activation of phosphatidylinositol-3 kinase (PI3K)/Akt pathway.Moreover,NAC could decrease manumycin-induced ROS generation and inhibit the effects of manumycin on the PI3K/Akt pathway and protect U937 cells from apoptosis induced by manumycin.Conclusion Manumycin induces apoptosis in U937 human leukemia cells through the regulation of the PI3K/Akt pathway and ROS production plays a critical role in the progress.

Telmisartan inhibits proliferation and induces apoptosis in U937 cells / 中国病理生理杂志

AIM: To demonstrate the effects of telmisartan on the proliferation and apoptosis of U937 cells.METHODS: The proliferation ability of the U937 cells was assessed by CCK-8 assay and colony formation test with methylcellulose.The CD11b expression rate of the U937 cells was identified by flow cytometry.The apoptotic rate was analyzed by flow cytometry with Annexin V-PI double staining and Hoechst 33342 staining.The protein levels of cleaved PARP and cleaved caspase-3 were determined by Western blot.RESULTS: The results of CCK-8 assay confirmed that the viability of U937 cells was inhibited by telmisartan.The colony formation capacity of U937 cells was also significantly inhibited by telmisartan.The differentiation of U937 cells was induced by telmisartan with the expression of CD11b.The results of flow cytometry analysis with Annexin V-PI double staining and Hoechst 33342 staining identified that the apoptosis of U937 cells was induced by telmisartan in dose-dependent and time-dependent manners with the up-regulation of cleaved PARP and cleaved caspase-3 proteins.CONCLUSION: Telmisartan inhibits the proliferation and induces the differentiation of U937 cells.Telmisartan also induces the apoptosis of U937 cells through the caspase pathway.

Promotion of immune response by soluble Tim-3 in vitro and therapeutic potential / 军事医学

Objective To evaluate the role of recombinant human soluble Tim-3 (hTim-3-Fc) in regulating immune response.Methods Soluble hTim-3 was incubated with human macrophage cell line U 937, human T cell line Jurkat and normal human PBMC before cytokines secreted by or expressed in different immune cells were analyzed using ELISA , RT-PCR and Western-blotting, respectively.Results Soluble hTim-3 significantly promoted the activation of different immune cells.Our data showed that IL-8 secretion by U937 cells, IL-2 secretion by Jurkat cells , IL-2 and IFN-γsecretion by human PBMCs were all significantly increased .In addition , soluble hTim-3 significantly increased the IFN-α2 and IFN-β1 mRNA expression in U937, Jurkat and PBMCs and increased the phosphorylation of stat-1 in Jurkat and U937 cells.Conclusion Recombinant soluble hTim-3 can significantly promote the activation of immune cells in vitro, which shows its therapeutic potential .

Proteomic profile of human monocytic cells infected with dengue virus

Objective To identify the changes in the proteome of U937 cells infected with dengue virus (DENV). Methods In this study, differentiated U937 cultures were infected with two DENV-2 strains, one of which was associated with dengue (DENV-2/NG) and the other one with severe dengue (DENV-2/16681), with the aim of determining the cellular proteomic profiles under different infection conditions. Cellular proteins were extracted and separated by two-dimensional electrophoresis, and those proteins with differential expression profiles were identified by mass spectrometry. The obtained results were correlated with cellular viability, the number of infectious viral particles, and the viral DNA/protein quantity. Results In comparison with non-infected cultures, in the cells infected with the DENV-2/NG strain, nine proteins were expressed differentially (five were upregulated and four were downregulated); in those cultures infected with the DENV-2/16681 strain, six proteins were differentially expressed (two were downregulated and four were upregulated). The downregulated proteins included fatty acid-binding protein, heterogeneous nuclear ribonucleoprotein 1, protein disulfide isomerase, enolase 1, heat shock 70 kDa protein 9, phosphotyrosyl phosphatase, and annexin IV. The upregulated proteins included heat shock 90 kDa protein AA1, tubulin beta, enolase 1, pyruvate kinase, transaldolase and phospholipase C-alpha. Conclusions Because the monocyte/macrophage lineage is critical for disease pathogenicity, additional studies on these proteins could provide a better understanding of the cellular response to DENV infection and could help identify new therapeutic targets against infection.

Zoledronic acid inhibits proliferation and induces apoptosis in U937 cells / 中国病理生理杂志

[ ABSTRACT] AIM:To study the antiproliferation and proapoptotic effects of zoledronic acid ( ZOL) on human a-cute myeloid leukemia cell line U937.METHODS:The viability of U937 cells was detected by CCK-8 assay.The cell cy-cle of the U937 cells was analyzed by flow cytometry with PI staining.Apoptotic rate was assessed by flow cytometry with Annexin V-PI and Hoechst 33342 staining.Mitochondrial membrane potential was detected by JC-1 assay.Methylcellulose was used to assess colony formation.The protein levels of p21, Bcl-2 and Bax were determined by Western blot.RE-SULTS:ZOL inhibited the viability of U937 cells.ZOL induced S-phase cell cycle arrest in the U937 cells.The results of flow cytometry analysis with Annexin V-PI and Hoechst 33342 staining showed that ZOL also induced apoptosis in a dose-and time-dependent manner.Mitochondrial membrane potential assay was also used to verify the apoptosis.The apoptotic rate was consistent with the reduction of mitochondrial membrane potential.Colony formation assay showed that ZOL signifi-cantly inhibited the colony formation capacity of the U937 cells.This was achieved by the induction of S-phase cell cycle arrest, and up-regulation of Bax and p21, and down-regulation of Bcl-2.CONCLUSION:ZOL inhibits cell proliferation by regulating the expression of cell cycle-related protein, and induces apoptosis via the mitochondrial apoptotic pathway.

Molecular association of CD98, CD29, and CD147 critically mediates monocytic U937 cell adhesion

Adhesion events of monocytes represent an important step in inflammatory responses induced by chemokines. The β1-integrin CD29 is a major adhesion molecule regulating leukocyte migration and extravasation. Although several adhesion molecules have been known as regulators of CD29, the molecular interactions between CD29 and its regulatory adhesion molecules (such as CD98 and CD147) have not been fully elucidated. Therefore, in this study, we examined whether these molecules are functionally, biochemically, and cell-biologically associated using monocytic U937 cells treated with aggregation-stimulating and blocking antibodies, as well as enzyme inhibitors. The surface levels of CD29, CD98, and CD147 (but not CD43, CD44, and CD82) were increased. The activation of CD29, CD98, and CD147 by ligation of them with aggregation-activating antibodies triggered the induction of cell-cell adhesion, and sensitivity to various enzyme inhibitors and aggregation-blocking antibodies was similar for CD29-, CD98-, and CD147-induced U937 cell aggregation. Molecular association between these molecules and the actin cytoskeleton was confirmed by confocal microscopy and immunoprecipitation. These results strongly suggest that CD29 might be modulated by its biochemical and cellular regulators, including CD98 and CD147, via the actin cytoskeleton.

Proteomic profile of human monocytic cells infected with dengue virus

Objective: To identify the changes in the proteome of U937 cells infected with dengue virus (DENV). Methods: In this study, differentiated U937 cultures were infected with two DENV-2 strains, one of which was associated with dengue (DENV-2/NG) and the other one with severe dengue (DENV-2/16681), with the aim of determining the cellular proteomic profiles under different infection conditions. Cellular proteins were extracted and sepa-rated by two-dimensional electrophoresis, and those proteins with differential expression profiles were identified by mass spectrometry. The obtained results were correlated with cellular viability, the number of infectious viral particles, and the viral DNA/protein quantity. Results: In comparison with non-infected cultures, in the cells infected with the DENV-2/NG strain, nine proteins were expressed differentially (five were upregulated and four were downregulated); in those cultures infected with the DENV-2/16681 strain, six proteins were differentially expressed (two were downregulated and four were upregu-lated). The downregulated proteins included fatty acid-binding protein, heterogeneous nuclear ribonucleoprotein 1, protein disulfide isomerase, enolase 1, heat shock 70 kDa protein 9, phosphotyrosyl phosphatase, and annexin IV. The upregulated proteins included heat shock 90 kDa protein AA1, tubulin beta, enolase 1, pyruvate kinase, transaldolase and phospholipase C-alpha. Conclusions: Because the monocyte/macrophage lineage is critical for disease patho-genicity, additional studies on these proteins could provide a better understanding of the cellular response to DENV infection and could help identify new therapeutic targets against infection.

Regulation of Dickkopf (DKK1) on apoptosis of U937 cell / 中国药学杂志

OBJECTIVE: To explore the regulation of Dickkopf (DKK1) on apoptosis of human acute leukemia U937 cell. METHODS: The reactive oxygen species (ROS) was assessed with DCFH-DA fluorescence probe; the mitochondria membrane potential was assessed with JC-1 staining method, apoptosis rate was detected by AnnexinV-FITC/PI double staining, Western-blot was used to analyse the expression of related protein. RESULTS: Dickkopf can rise the ROS and reduce the mitochondria membrane potential, meanwhile up-regulate the expressing of BAX, down-regulating expressing of Mcl-1 and Bcl-2. CONCLUSION: Dickkopf can promote apoptosis of human acute leukemia U937 cell.

Autophagy and apoptosis of acute myelogenous leukemia U937 cell induced by Sirolimus / 中华实用儿科临床杂志

Objective To investigate the autophagy and apoptosis in acute myelogenous leukemia U937 cell induced by Sirolimus.Methods U937 cells were subcultured, and blank control group(normal) and Sirolimus treated groups(12 h, 24 h,48 h) were established.The Sirolimus treated groups were treated by 2 μmol/L concentration of Sirolimus for 12 h,24 h and 48 h, respectively.The cell morphology of U937 cells treated by Sirolimus was observed after 12 h,24 h and 48 h.The survival rate of cells was detected by cell counting kit-8 method.Cell apoptosis was detected by flow cytometry using Annexin V-FITC/PI double labeled.Real-time PCR was used to detect the level of mRNA expression in autophagy specific protein maker mictotubule-associated protein light chain 3 (LC3)-Ⅱ in different treated times by Sirolimus.Sirolimus LC3 protein expression levels after treatment were detected by Western blot method.Results Under inverted microscope, the cell number of Sirolimus treatment group reduced gradually after 12 h ,24 h and 48 h culture, volume of cells became smaller, cells got ruptured, and the nucleus pycnosis and cellular debris increased.With the extension of time, U937 cells survival rate was falling, and there was statistical differences compared with those of the control group(P =0.031).With Sirolimus treatment, U937 cells after 12 h,24 h and 48 h, U937 cell apoptosis rate increased, and there were statistically significances, compared with those of the control group (P =0.027).With Sirolimus treatment U937 cells after 12 h,24 h and 48 h,LC3-Ⅱ mRNA expression and protein expression were down-regulated compared with those of the control group, and there were statistically significances (P =0.029).Conclusions Sirolimus can induce autophagy and apoptosis in U937 cells.Autophagy protein LC3-Ⅱ in gene and protein expression levels were lowered, and LC3-Ⅱ may play an important role in regulating the leukemia cell autophagy.

Biological activity and application study of a monoclonal antibody against human Tim-3 / 军事医学

Objective To develop a human Tim-3 specific monoclonal antibody and evaluate its biological activity and possible use in clinical diseases associated with dysregulated Tim-3 expression .Methods The BALB/c mice were immu-nized by conventional method, and positive clones were used to develop anti-human Tim-3 antibody, the binding and neutralization activities of which in vitro and in vivo were investigated.Results ①A monoclonal antibody (clone L3D) which could specifically bind to human Tim-3 protein in ELISA assay was obtained and the subtype of the monoclonal antibody was IgG2a .②Flow cytometry indicated that the monoclonal antibody could bind to Tim-3 expressed in human U937 cells.This antibody also showed a cross activity to mice′Tim-3.③The monoclonal antibody inhibited the apoptosis of THP1 cells induced by Gal-9, the ligand of Tim-3.④Injection of Tim-3 antibody exacerbated sepsis in mice as marked by the decreased survival rate and increased expression of pro-inflammatory cytokines .Conclusion An anti-human Tim-3 monoclonal antibody is successfully obtained.The excellent binding and neutralization activities of this antibody enable it to be widely used in clinical diseases associated with deregulated Tim-3 expression .

Regulation of 18β-glycyrrhetinic acid on apoptosis of U937 cell through activation of Wnt/β-catenin signal / 中国药学杂志

OBJECTIVE: To explore the regulation of 18β-glycyrrhetinic acid on apoptosis of human acute leukemia U937 cell through Wnt/β-catenin signal.

Induction of apoptosis by a hexane extract of aged black garlic in the human leukemic U937 cells

BACKGROUND/OBJECTIVES: In this study, the apoptogenic activity and mechanisms of cell death induced by hexane extract of aged black garlic (HEABG) were investigated in human leukemic U937 cells. MATERIALS/METHODS: Cytotoxicity was evaluated by MTT (3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyl tetrazoliumbromide) assay. Apoptosis was detected using 4,6-diamidino-2-phenyllindile (DAPI) staining, agarose gel electrophoresis and flow cytometry. The protein levels were determined by Western blot analysis. Caspase activity was measured using a colorimetric assay. RESULTS: Exposure to HEABG was found to result in a concentration- and time-dependent growth inhibition by induction of apoptosis, which was associated with an up-regulation of death receptor 4 and Fas legend, and an increase in the ratio of Bax/Bcl-2 protein expression. Apoptosis-inducing concentrations of HEABG induced the activation of caspase-9, an initiator caspase of the mitochodrial mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase. HEABG also induced apoptosis via a death receptor mediated extrinsic pathway by caspase-8 activation, resulting in the truncation of Bid, and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. However, pre-treatment of U937 cells with the caspase-3 inhibitor, z-DEVD-fmk, significantly blocked the HEABG-induced apoptosis of these cells, and increased the survival rate of HEABG-treated cells, confirming that HEABG-induced apoptosis is mediated through activation of caspase cascade. CONCLUSIONS: Based on the overall results, we suggest that HEABG reduces leukemic cell growth by inducing caspase-dependent apoptosis through both intrinsic and extrinsic pathways, implying its potential therapeutic value in the treatment of leukemia.

In vitro cytotoxicity testing of new generation oxazaphosphorines against human histiocytic lymphoma cells.

Oxazaphosphorines belong to a group of alkylating agents. Mafosfamide cyclohexylamine salt (D-17272), 4-hydro-peroxy-cyclophosphamide (D-18864) and glufosfamide (D-19575, β-D-glucose-isophosphoramide mustard) are new generation oxazaphosphorines. The objective of the present study was to compare the cytotoxic action of these oxazaphosphorine compounds against human histiocytic lymphoma U937 cells. The chemical structures of the oxazaphosphorines were responsible for the different responses of U937 cells. The cytotoxic effects of D-17272, D-18864, and D-19575 on U937 cells depended on the agent tested, its dose, and the time intervals after the oxazaphosphorine application. Among the oxazaphosphorine agents, D-18864 appeared to be the most cytotoxic, and D-19575 was characterized by the lowest cytotoxicity. The in vitro cytotoxic activities of the oxazaphosphorines were strongly associated with their cell death inducing potential.

HS-1200 Overcomes the Resistance Conferred by Bcl-2 in Human Leukemic U937 Cells

Bcl-2 protects tumor cells from the apoptotic effects of various anti-neoplastic agents. Increased expression of Bcl-2 has been associated with a poor response to chemotherapy in various malignancies, including leukemia. Hence, bypassing the resistance conferred by anti-apoptotic factors such as Bcl-2 represents an attractive therapeutic strategy against cancer cells, including leukemic cells. This study was undertaken to examine whether the anticancer drug, cisplatin and the synthetic chenodeoxycholic acid (CDCA) derivative, HS-1200 show anti-tumor activity in U937 and U937/Bcl-2 cells. Viability assays revealed that HS-1200 overcomes the resistance conferred by Bcl-2 in human leukemic U937 cells. Various apoptosis assessment assays further demonstrated that HS-1200 overcomes the resistance conferred by Bcl-2 in human leukemic U937 cells by inducing apoptosis. In addition HS-1200, but not cisplatin, overcomes the anti-apoptotic effects of Bcl-2 in Bcl-2 over-expressing human leukemic cells (U937/Bcl-2 cells). Notably, we observed that the HS-1200-induced formation of mature promyelocytic leukemia (PML) nuclear bodies (NBs) correlates with a suppression of the anti-apoptotic effects of Bcl-2 in human leukemic cells over-expressing this protein (U937/Bcl-2 cells). Furthermore, HS-1200 was found to induce the association between PML and SUMO-1, Daxx, Sp100, p53 or CBP in the aggregated PML-NBs of U937/Bcl-2 cells. Thus, PML protein and the formation of mature PML-NBs could be considered as therapeutic targets that may help to bypass the resistance to apoptosis conferred by Bcl-2. Elucidating the exact mechanism by which PML regulates Bcl-2 will require further work.

Effects of antisense oligonucleotides targeting miRNA-214 on human leukemia U937 cells / 白血病·淋巴瘤

Objective To explore the inhibitory effect of anti-miRNA-214 oligonucleotide on leukemia U937 cells.Methods U937 cells were transfected with anit-miRNA-214 oligonucleotide,cell viability was analyzed by MTT assay.Apoptosis was detected by flow cytometry.The expression of miRNA214 in the U937 cells were measured by real-time PCR.Results The MTT result showed that the growth of U937 cells treated with AMO-miRNA-214 in 24 h,48 h,72 h was obviously inhibited (0.812±0.001,0.770±0.002,0.541±0.001),compared with those in control groups (randomized control 1.011±0.002,1.112±0.003,1.111±0.003,blank control 1.112±0.001,1.023±0.001,1.101±0.001),the differences had statistical significance (F =2.782,3.659,2.735,P =0.021,0.018,0.036).The flow cytometry results showed that the apoptosis detected in AMO-miRNA-214 group at 48 h,72 h (15.12±0.02,19.14±0.01) had significant differences compared with those in control groups (randomized control 2.04±0.02,2.45±0.03,blank control 1.19±0.02,2.02±0.01) (F =3.683,3.762,P =0.013,0.015).The expression of miRNA-214 was downregulated significantly in U937 cells after treated with oligonucleotide (31.1±0.2) compared with those in control groups (randomized control 25.8±0.1,blank control 25.6±0.2) (P ＜ 0.05).Conclusion Targeted inhibition of miRNA-214 with oligonucleotide can suppress U937 cells growth and induce apoptosis.

Effects of RNA interference targeting HOXA9 on the proliferation and apoptosis of human acute monocytic leukemia U937 cells / 肿瘤研究与临床

Objective To investigate the effects of small interference RNA (siRNA) targeting HOXA9 on the proliferation and apoptosis of human acute monocytic leukemia U937 cell line.Methods Effective and specific siRNA oligo targeting HOXA9 was designed and compounded.It was transfected transiently into U937 cells by cationic liposome.The cells was divided into three groups:experimental group(siRNA targeting HOXA9 was transfected by liposome),negative control group (negative siRNA was transfected by liposome) and cell control group (add equal cells and medium).The expression of HOXA9 mRNA and protein were detected by reverse transcription PCR and Western blot.The cell proliferation was assessed by MTT.The apoptosis of each group were measured by Annexin V-FITC.Results Aftcr transfected by siRNA targeting HOXA9,the relative mRNA expression levels of HOXA9 in the experimental group,negative control group and cell control group were (22.980±0.548) ％,(82.371±1.517) ％ and (84.637±2.252) ％,respectively (P ＜ 0.05),and the relative protein expression levels were (50.377±2.773).％,(105.500±3.900) ％ and (111.392±3.905) ％,respectively (P ＜ 0.05).The inhibitory rates of cell proliferation and the apoptosis rates of the experimental group were significantly increased.The inhibitory rates of cell proliferation of 24 h,48 h and 72 h were (41.909±4.333) ％,(54.470±3.756) ％ and (65.835±1.024) ％,respectively,and the apoatosis rate was (26.800±2.081) ％.Compared with 2 controls,the experimental group differences had statistically significance (P ＜ 0.05).Conclusion siRNA targeting HOXA9 can effectively silence HOXA9 gene expression in U937 cell,suppress cell proliferation and induce cell apoptosis obviously,which providing experimental basis for clinical lenkemia therapy by targeting HOXA9 gene.