INDUCTION OF APOPTOSIS OF HUMAN LEUKEMIA CELLS BY α-ANORDRIN

The apoptosis-inducing effect of a-anordrin (ANO)was investigated in this study. ANO 10-50 AM inhibited the growth of both human leukemia HL-60 and K562cells by 19-52%. Electron microscopy showed that ANO-treated cells exhibited the drastic changes including cell shrinkage, chromatin condensation, nuclear fragmentation, typical of apoptosis. Gel electrophoresis of DNA extracted farm botlt HL-60 and K562 cells treated with ANO revealed characteristic 'ladder' pattern.ANO 50 μM for 48 h caused approximately 50-70%apoptosis. Cycloheximide (CHX) and actinomycin D (Act D) did not prevent ANO-induced apoptosis in K562cells, however, apoptosis of HL-60 cells in the presence of ANO was partially blocked by these two agents.Moreover, it was found that tamoxifen synergically potcntiated and cstradiol partially antagonized ANOinduccd apoptosis in HL-60 cells. Results demonstrated that ANO could induce tumor cell apoptosis, which might contribute to its anticancer action.

Resveratrol Induces Apoptosis and Autophagy in T-cell Acute Lymphoblastic Leukemia Cells by Inhibiting Akt/mTOR and Activating p38-MAPK

Objective To explore the effects of resveratrol-induced apoptosis and autophagy in T-cell acute lymphoblastic leukemia （T-ALL） cells and potential molecular mechanisms. Methods The anti-proliferation effect of resveratrol-induced, apoptosis and autophagy on T-ALL cells were detected by using MTI- test, immunofluorescence, electronic microscope, and flow cytometry, respectively. Western blotting was performed for detecting changes of apoptosis-associated proteins, cell cycle regulatory proteins and state of activation of Akt, mTOR, p70S6K, 4E-BP1, and p38-MAPK. Results Resveratrol inhibited the proliferation and dose and time-dependent manner. It also induced cyclin-dependent kinase （CDK） inhibitors p21 and induced apoptosis and autophagy in T-ALL cells in a cell cycle arrest at G0/G1 phase via up regulating p27 and down regulating cyclin A and cyclin D1. Western blotting revealed that resveratrol significantly decreased the expression of antiapoptotic proteins （Mcl-1 and Bcl-2） and increased the expression of proapoptotic proteins （Bax, Bim, and Bad）, and induced cleaved-caspase-3 in a time-dependent manner. Significant increase in ratio of LC3-11/LC3-1 and Beclin 1 was also detected. Furthermore, resveratrol induced significant dephosphorylation of Akt, mTOR, p70S6K, and 4E-BP1, but enhanced specific phosphorylation of p38-MAPK which could be blocked by SB203580. When autophagy was suppressed by 3-MA, apoptosis in T-ALL cells induced by resveratrol was enhanced. Conclusion Our findings have suggested that resveratrol induces cell cycle arrest, apoptosis, and autophagy in T-ALL cells through inhibiting Akt/mTOR/p7OS6K/4E-BP1 and activating p38-MAPK signaling pathways. Autophagy might play a role as a self-defense mechanism in T-ALL cells treated by resveratrol. Therefore, the reasonable inhibition of autophagy in T-ALL cells may serve as a promising strategy for resveratrol induced apoptosis and can be used as adjuvant chemotherapy for T-ALL.

Phosphomonoester Phosphoethanolamine Induces Apoptosis in Human Chronic Myeloid Leukemia Cells

Background:Leukemia is a type of cancer that starts in the blood or blood-forming tissues.It results from the clonal proliferation of hematopoietic cells in the bone marrow and/or lymphoid tissues,which subsequently reach the peripheral circulation and can infiltrate other systems.There are many different kinds of leukemia,and treatments are different for each one.Chronic leukemia is with a slower growing than acute leukemia but could be just as life-threatening.Phospholipids are antitumor analogs,such as synthetic phosphoethanolamine,which is a phosphorylated compound capable of controlling cellular proliferation and inducing apoptosis in several types of tumor cells.Methods:K562 and K562-Lucena(MDR+)human chronic myeloid leukemia cells were treated with synthetic phosphoethanolamine(Pho-s).The viability was evaluated by sulforhodamine B(SRB)assay and cell cycle phases,apoptosis,markers expression,and mitochondrial potential were assessed by flow cytometry.Results:Tumor cells formed clusters in suspension and decreased significantly viability.The concentrations for IC50%were obtained.Pho-s treated were 43.1 mM(K562)and 145.9 mM(K562-Lucena MDR+)in a period of 24 hours.Pho-s induced changes in the distribution of cell population phases of cell cycle which showed an increase in fragmented DNA and increased markers expression envolved apoptosis pathways a decrease in the G1/G0 phase.Discussion:Treatment of K562 and K562-Lucena(MDR+)chronic myeloid leukemia cells with Pho-s showed dose and time dependent cytotoxic effects.This cytotoxicity induced a decrease in proliferative capacity,mitochondrial electrical potential,and consequently release of cytochrome C;inhibition of Bcl-2 family protein expression,increase in pro-apoptotic family members Bad and Bax,dependent on p53 expression.Conclusion:This study presented a significant therapeutic potential of Phos-s in this type of leukemia through the apoptotic effects on tumor cells independently of the molecular resistance profile(MDR+).

Arsenic Trioxide Induces Apoptosis of Glucocorticoid-Resistant Acute Lymphoblastic Leukemia CEM-C1 Cells

Objective： To explore the effects of arsenic trioxide （ATO） on the apoptosis of glucocorticoid （GC）-resistant T-acute lymphoblastic leukemia （ALL） CEM-C1 cells and its possible mechanisms. Methods： Different concentrations of ATO （0.25 μmol/L-5 μmol/L） were used to induce the apoptosis of CEM-C1 cells. The inhibition rate of cell proliferation and apoptosis were detected by MTT test, Annexin V-FITC/PI flow cytometry and optical microscopy, respectively. RT-PCR was applied to semi-quantitatively analyze the mRNA expression of pro-apoptotic proteins （Bad and PDCD4） and anti-apoptotic proteins （XIAP and MCL-1） induced by different concentrations of ATO at different time points. Results： ATO could inhibit proliferation and induce apoptosis of CEM-C1 cells at a concentration and time dependent manner. Low-dose ATO mildly inhibited the proliferation of CEM-C1 cells while higher concentrations （1 μmol/L and 5 μmol/L） had strong anti-tumor effect with the inhibiting rates of 40.07±7.98% and 88.67±2.88%, respectively. Annexin V-FITC/PI flow cytometry showed that the apoptotic rates of CEM-C1 ceils were significantly increased after 48 hours treatment of different concentrations of ATO. RT-PCR demonstrated up-regulated mRNA expression of pro-apoptotic protein Bad and PDCD4 but down-regulated mRNA expression of anti-apoptotic protein XIAP when CEM-C1 cells were treated with different concentrations of ATO at different time points. The MCL-1 mRNA expression was down-regulated only after the treatment of 5 μmol/L ATO. Conclusion： ATO can inhibit cell proliferation and induce cell apoptosis in GC-resistant CEM-C1 cells. The molecular mechanisms might involve the increased mRNA expression of pro-apoptotic protein Bad and PDCD-4, and rapid down-regulation of XIAP mRNA expression.

Hepatopoietin Cn suppresses apoptosis of human hepatocellular carcinoma cells by up-regulating myeloid cell leukemia-1

AIM:To investigate the role of hepatopoietin Cn(HPPCn) in apoptosis of hepatocellular carcinoma(HCC)cells and its mechanism. METHODS:Two human HCC cell lines,SMMC7721 and HepG2,were used in this study.Immunostaining, Western blotting and enzyme linked immunosorbent assay were conducted to identify the expression of HPPCn and the existence of an autocrine loop of HPPCn/ HPPCn receptor in SMMC7721 and HepG2.Apoptotic cells were detected using fluorescein isothiocyanate (FITC)-conjugated Annexin V and propidium iodide.RESULTS:The HPPCn was highly expressed in human HCC cells and secreted into culture medium(CM). FITC-labeled recombinant human protein(rhHPPCn) could specifically bind to its receptor on HepaG2 cells. Treatment with 400 ng/mL rhHPPCn dramatically increased the viability of HCC-derived cells from 48.1% and 36.9%to 85.6%and 88.4%,respectively(P< 0.05).HPPCn silenced by small-interfering RNA reduced the expression and secretion of HPPCn and increased the apoptosis induced by trichostatin A.Additionally, HPPCn could up-regulate the expression of myeloid cell leukemia-1(Mcl-1)in HCC cells via mitogen-activated protein kinase(MAPK)and sphingosine kinase-1. CONCLUSION:HPPCn is a novel hepatic growth factor that can be secreted to CM and suppresses apoptosis of HCC cells by up-regulating Mcl-1 expression.

The Role of Mitochondrial VDAC2 in the Survival and Proliferation of T-Cell Acute Lymphoblastic Leukemia Cells

Background: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with aberrant T-cell developmental arrest. Individuals with relapsed T-ALL have limited therapeutic alternatives and poor prognosis. The mitochondrial function is critical for the T-cell viability. The voltage-dependent anion channel 2 (VDAC2) in the mitochondrial outer membrane, interacts with pro-apoptotic BCL-2 proteins and mediates the apoptosis of several cancer cell lines. Objective: The aim of the current study is to explore the role of VDAC2 in T-ALL cell survival and proliferation. Methods: Publicly available datasets of RNA-seq results were analyzed for expression of VDAC isoforms and T-ALL cell lines were treated with a VDAC2 small molecular inhibitor erastin. A VDAC2 RNA interference (siRNA) was delivered to T-ALL cell lines using a retroviral vector. Functional assays were performed to investigate the VDAC2 siRNA impacts on cell proliferation, apoptosis and survival of T-ALL cells. Results: Our analysis found a high expression of VDAC2 mRNA in various T-ALL cell lines. Public datasets of T-ALL RNA-seq also showed that VDAC2 is highly expressed in T-ALL (116.2 ± 36.7), compared to control groups. Only two T-ALL cell lines showed sensitivity to erastin (20 μM) after 48 hours of incubation, including Jurkat (IC50 = 3.943 μM) and Molt4 (IC50 = 3.286 μM), while another two T-ALL cells (CUTLL1 and RPMI 8402) had unstable IC50. However, five T-ALL cell lines (LOUCY, CCRF-CEM, P12-ICHI, HPB-ALL, and PEER cells) showed resistance to erastin. On the contrary, all T-ALL cell lines genetically inhibited with VDAC2 siRNA led to more than 80% decrease in VDAC2 mRNA levels, and a Conclusion: VDAC2 is highly expressed in T-ALL cells. The inhibition of VDAC2 significantly decreased cell viability, increased apoptosis, reduced cell proliferation and caused cell cycle sub-G1 arrest of T-ALL cells.

Study on the mechanism of apoptosis of myelocytic leukemia cell lines induced by curcumin

Objective: To investigate the mechanism of apoptosis of myelocytic leukemia lines NB4, K562 and THP-1 cells induced by curcumin. Methods: After the cells were treated with curcumin at different concentration (25, 12.5, 6.25, 3.125, 0 μmol/L) for various times (0, 12, 24, 48 h), flow cytometry (FCM) was used to determine the rate of apoptosis of cells. After the cells were treated with curcumin at 25 μmol/L for 24 h, flow cytometry was used to determine the expression level of Fas, and Western blot was performed to determine the expression of Caspase-8 and Caspase-9. Results: (1) Curcumin could induced the apoptosis of NB4, K562 and THP-1 cells in a time- and dose-dependent manner. After the cells were treated with curcumin at 25 μmol/L for 48 h, the rate of apoptosis of cells was over fifty percent. (2) Fas level showed remarkable increase (P < 0.01) after above cells were treated with 25 μmol/L curcumin for 24 h. (3) The apoptosis proteins of Caspase-8 and Cas- pase-9 were also increased obviously (P < 0.01) after the cells were treated with 25 μmol/L curcumin for 24 h. Conclusion: The molecular pathway of apoptosis of myelocytic leukemia lines induced by curcumin are concerned with death receptor and mitochondria.

ANALYSIS OF APOPTOSIS BY DNA END LABELING METHOD (TDT) IN LEUKEMIA CELL LINES HL-60 AND U937

Antitumor-drug-indnced apoptosis in leukemia cell lines HL-60 and U937 was quantitatively analyzed with TDT (terminal deoxynuleotidyl transferase-mediated nick-end labeling) approach, which allows to labal the ends of DNA broken strands in apoptotic cells by biotinlated dUTP which to avidin-FITC. In this way the apoptotic cells show nuorescent when the labeling cells were emitted by UV light microscope or laser-activated now cell sorting at r=480. In our study, HL-6o and U937 cell lines were cocultured respectively with cisdiaminodicaicroplatinum (CDDP), hydroxycamptothecinum (HCT) and vindesini sulfa (VCR) for 18 hours.By calculating percentages of apoptotic cells with TDT mothod, we were able to show that the two cell lines gave different sensitivity to the drugs. HL-60 showed high sensitivity to CDDP but U937 cells were more sensitive to other two drugs, HCT and VCR. Meanwhile we compared the results of obtained by DNA gel electrophoresis with that by TDT. We found that gel electrophoresis is not sensitive enough to reveal apoptosis since there was no ladder structure, a typical electrophoresis pattern for apoptosis, appeared until the apoptotic cells reached or over 13%. And we report in this paper as first time that three forms of apoptotic cells could be detected under fluorescent microscope, which we called as spot form and crescent form and assembling form in terms of distribution of light spots within cell nuclei. It seemed that the spot form was at an early stage of apoptosis and the crescent form rcprtscntcd a later stage of apoptosis.

Study on Taxol in Inhibiting Human Leukemia Cell Proliferation andInducing Apoptosis

Objective: To explore the effects of Taxol in inhibiting human leukemia k562 cell proliferation and inducing apoptosis in vitro. Methods: Human leukemia K562 cells were treated with Taxol of different concentrations for 12-72 hrs. Cell proliferation was evaluated by MTT assay and morphological changes of apoptosis were examined by microscopy. Cell apoptosis was determined by flow cytometry (FCM) and DNA gel electrophoresis. Results: Growth of K562 cells was inhibited by Taxol with an IC50 value of 0. 84μg/ml. Typical nuclear condensation and apoptosis bodies were observed as early as 24 hrs after a 0.5μg/ml Taxol treatment; Apoptotic rate of the Taxol-treated K562 cells increased from 3.7% to 24.0% in 24 hrs. No DNA ladder was observed by DNA gel electrophoresis. Conclusion: Taxol could inhibit K562 cell growth and induce apoptosis in vitro.

Pure total flavonoids from Citrus paradisi Macfadyen act synergistically with arsenic trioxide in inducing apoptosis of Kasumi-1 leukemia cells in vitro

To investigate the potential effects of pure total flavonoid compounds（PTFCs） from Citrus paradisi Macfadyen separately or combined with arsenic trioxide on the proliferation of human myeloid leukemia cells and the mechanisms underlying the action of PTFCs. The effects of PTFCs separately or combined with arsenic trioxide on the proliferation and apoptosis of leukemia cells were determined by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide（MTT）, fluorescence microscopy, and flow cytometry. Their effects on the expression levels of apoptosisrelated regulators were determined by Western blot assay. PTFCs combined with arsenic trioxide significantly inhibited the growth of Kasumi-1 cells, and apoptosis was confirmed by flow cytometry analysis. Hoechst 33258 staining showed more significant morphological changes and more apoptosis following the combined treatment. Western blots showed changes in the expression of genes for poly ADP-ribose polymerase（PARP）, caspase 3/9, and P65. The results indicated that PTFCs separately or combined with arsenic trioxide inhibited proliferation of leukemia cells in vitro and induced their apoptosis by modulating the expression of apoptosis-related regulator genes.

Berbamine selectively induces apoptosis of human acute promyelocytic leukemia cells via survivin-mediated pathway

Background Currently, resistance and relapse are still major problems in acute promyelocytic leukemia （APL） cases. Thus, new agents that override the resistance are crucial to the development of curative therapies for APL. In this study, we investigated the effects of berbamine on the proliferation of APL cell line NB4 and its possible mechanisms. Methods NB4 cells were treated with berbamine at different concentrations （0-64 μg/ml） for 72 hours. MTT assay was used to determine proliferation inhibition of NB4 cells. Cell apoptosis was evaluated by both flow cytometry （FCM） and morphological examination. PML/RAR-α and survivin mRNAs were measured by nested-RT-PCR and RT-PCR, respectively. Activated-caspase 3 was determined by FCM. Results Berbamine greatly inhibited the proliferation of NB4 cells in dose- and time-dependent manners, and its IC50 value was 3.86 μg/ml at 48 hours. Both morphological observations and FCM results showed that berbamine induced apoptosis of NB4 cells with concomitant increase of activated caspase-3 and decrease of survivin mRNA. After treatment with berbamine at 8 μg/ml for 48 hours, the percentage of apoptotic cells increased from 2.83% to 58.44% （P〈0.01）, and the percentage of cells with activated-caspase 3 elevated from 2.06% to 70.89% （P〈0.01）, whereas, level of survivin mRNA was reduced to 38.24% of control （P〈0.01）. However, no significant change was observed in PML/RAR-α mRNA.Conclusions Berbamine induces caspase-3-dependent apoptosis of leukemia NB4 cells via survivin-mediated pathway, suggesting that berbamine may be a novel potential agent against APL with a mechanism distinct from that of all-trans retinoic acid （ATRA） and arsenic trioxide （ATO）.

INHIBITION OF NF-κB ACTIVITY ENHANCED CYTOSINE ARABINOSIDE INDUCED APOPTOSIS IN LEUKEMIC CELL LINE HL60-N

Objective: To explore the effects of dexamethasone (DXM) and vincristine (VCR) on cytosine arabinoside (Ara-C) induced apoptosis and activation of nuclear factor-k-gene binding (NF-kB) in leukemic cell line HL60-n. Methods: Apoptosis of HL60-n cells was analysed by TdT-mediated X-dUTP nick and end labeling (TUNEL) and DNA electrophoresis. NF-kB activity of HL60-n cells was detected by electrophoretic mobility shift assay (EMSA). Results: There was slight activation of NF-kB in HL60-n cells without drug induction. Ara-C at 1 mmol/L significantly enhanced the activation of NF-kB in HL60-n cells. The level of NF-kB activation induced by DXM at 1 mmol/L or VCR at 0.1 mmol/L had no significant difference compared with that of the control group. However, in HL60-n cells pre-treated with 1 mmol/L of DXM or 0.1 mmol/L of VCR, the activation of NF-kB induced by 1 mmol/L of Ara-C was significantly suppressed with inhibition rates of 31.0% and 47.0%, respectively. The apoptosis rates of HL60-n cells induced by 1.0 mmol/L, 10 mmol/L and 100 mmot/L Ara-C were 45.003.16%, 61.883.40% and 77.624.75%, respectively. The apoptotic rates of HL60-n cells induced by DXM at 1 mmol/L or VCR at 0.1 mmol/L were similar to that of the control group. However, either DXM at 1 mmol/L or VCR at 0.l mmol/L could enhance the apoptosis of HL60-n cells induced by Ara-C at 1 mmol/L with rates of 39.1% and 59.2%, respectively. Conclusion: Ara-C can induce apoptosis and activation of NF-kB in HL60-n cells. The mechanism of increased apoptosis of HL60-n cells by DXM or VCR may be related to suppression of NF-kB activation.

Yinchenhao decoction attenuates obstructive jaundice-induced liver injury and hepatocyte apoptosis by suppressing protein kinase RNA-like endoplasmic reticulum kinase-induced pathway

BACKGROUND Chronic biliary obstruction results in ischemia and hypoxia of hepatocytes,and leads to apoptosis.Apoptosis is very important in regulating the homeostasis of the hepatobiliary system.Endoplasmic reticulum(ER)stress is one of the signaling pathways that induce apoptosis.Moreover,the protein kinase RNA-like endoplasmic reticulum kinase(PERK)-induced apoptotic pathway is the main way;but its role in liver injury remains unclear.Yinchenhao decoction(YCHD)is a traditional Chinese medicine formula that alleviates liver injury and apoptosis,yet its mechanism is unknown.We undertook this study to investigate the effects of YCHD on the expression of ER stress proteins and hepatocyte apoptosis in rats with obstructive jaundice(OJ).AIM To investigate whether YCHD can attenuate OJ-induced liver injury and hepatocyte apoptosis by inhibiting the PERK-CCAAT/enhancer-binding protein homologous protein(CHOP)-growth arrest and DNA damage-inducible protein 34(GADD34)pathway and B cell lymphoma/leukemia-2 related X protein(Bax)/B cell lymphoma/leukemia-2(Bcl-2)ratio.METHODS For in vivo experiments,30 rats were divided into three groups:control group,OJ model group,and YCHD-treated group.Blood was collected to detect the indicators of liver function,and liver tissues were used for histological analysis.For in vitro experiments,30 rats were divided into three groups:G1,G2,and G3.The rats in group G1 had their bile duct exposed without ligation,the rats in group G2 underwent total bile duct ligation,and the rats in group G3 were given a gavage of YCHD.According to the serum pharmacology,serum was extracted and centrifuged from the rat blood to cultivate the BRL-3A cells.Terminal deoxynucleotidyl transferase mediated dUTP nick end-labelling(TUNEL)assay was used to detect BRL-3A hepatocyte apoptosis.Alanine aminotransferase(ALT)and aspartate transaminase(AST)levels in the medium were detected.Western blot and quantitative real-time polymerase chain reaction(qRT-PCR)analyses were used to detect protein and gene expression levels of PERK,CHOP,GADD34,Bax,and Bcl-2 in the liver tissues and BRL-3A cells.RESULTS Biochemical assays and haematoxylin and eosin staining suggested severe liver function injury and liver tissue structure damage in the OJ model group.The TUNEL assay showed that massive BRL-3A rat hepatocyte apoptosis was induced by OJ.Elevated ALT and AST levels in the medium also demonstrated that hepatocytes could be destroyed by OJ.Western blot or qRT-PCR analyses showed that the protein and mRNA expression levels of PERK,CHOP,and GADD34 were significantly increased both in the rat liver tissue and BRL-3A rat hepatocytes by OJ.The Bax and Bcl-2 levels were increased,and the Bax/Bcl-2 ratio was also increased.When YCHD was used,the PERK,CHOP,GADD34,and Bax levels quickly decreased,while the Bcl-2 levels increased,and the Bax/Bcl-2 ratio decreased.CONCLUSION OJ-induced liver injury and hepatocyte apoptosis are associated with the activation of the PERK-CHOP-GADD34 pathway and increased Bax/Bcl-2 ratio.YCHD can attenuate these changes.

PEG10 Activation by Co-Stimulation of CXCR5 and CCR7 Essentially Contributes to Resistance to Apoptosis in CD19^(+)CD34^(+) B Cells from Patients with B Cell Lineage Acute and Chronic Lymphocytic Leukemia

We investigated CD19^+CD34^+ and CD19^+CD34 B cells from cord blood (CB) and typical patients with B cell lineage acute and chronic lymphocytic leukemia (B-ALL and B-CLL) in terms of expression and functions of CXCR5/CXCL13 and CCR7/CCL19.CXCR5 and CCR7 were selectively frequent expressed on B-ALL,B-CLL and CB CD19^+CD34^+ B cells,but not on CD19^+CD34 B cells.Instead of induction of impressive chemotactic responsiveness,CXCL13 and CCL19 together induced significant resistance to TNF-α-mediated apoptosis in B-ALL and B-CLL but not CB CD19^+CD34^+ B cells.B-ALL and B-CLL CD19^+CD34^+ B cells expressed elevated level of Paternally Expressed Gene 10 (PEG10),and CXCL13 and CCL19 together significantly up-regulated PEG10 expression in the cells.We found that CXCL13 and CCL19 together by means of activation of CXCR5 and CCR7 up-regulated PEG10 expression and function,subsequent stabilized caspase-3 and caspase-8 in B-ALL and B-CLL CD19^+CD34^+ B cells,and rescued the cells from TNF-α-mediated apoptosis.We suggested that normal lymphocytes,especially naive B and T cells,utilized CXCR5/CXCL13 and CCR7/CCL19 for migration,homing,maturation,and cell homeostasis as well as secondary lymphoid tissues organogenesis. Meanwhile certain malignant cells took advantages of CXCR5/CXCL13 and CCR7/CCL19 for infiltration, resistance to apoptosis,and inappropriate proliferation.Cellular & Molecular Immunology.2004;1(4):280-294.

Elemene induces apoptosis and regulates expression of bcl-2 protein in human leukemia K562 ceLls

目的：研究榄香烯的抗肿瘤作用机制．方法：抑制细胞增殖采用ＭＴＴ法；用荧光显微镜观察细胞的形态学变化；ＤＮＡ电泳、流式细胞仪技术检测ＤＮＡ断裂；用流式细胞仪检测ｂｃｌ２蛋白的表达．结果：榄香烯６５－５２０μｍｏｌ·Ｌ－１明显抑制Ｋ５６２细胞增殖，ＩＣ５０（９５％可信区间）为２２０（１５２－３１９）μｍｏｌ·Ｌ－１，电泳可见ＤＮＡ断裂形成的阶梯状条带，形态学上表现为染色体聚集，核固缩、断裂，而ｂｃｌ２蛋白的水平明显下降．结论：榄香烯诱导人白血病Ｋ５６２细胞凋亡。

Proteomic analysis of nuclear matrix proteins during arsenic trioxide induced apoptosis in leukemia K562 cells

Background Arsenic trioxide (As2O3) has been identified as a very potent antiacute leukemic agent However its role in apoptosis needs to be elucidated As2O3 interferes with the proliferation and survival of tumor cells via a variety of mechanisms Drugtarget interactions at the level of nuclear matrix (NM) may be critical events in the induction of cell death by As2O3 This study dealt with As2O3-target interactions at the level of NM in chronic myelogenous leukemia cell line K562 by proteomics Methods K562 cells were cultured in MEM and treated with different concentrations of As2O3 The nuclear matrix proteins were analyzed by highresolution twodimensional gel electrophoresis and computerassisted image analysis Results As2O3 significantly inhibited the growth of chronic myelogenous leukemia cell line K562 at low concentrations While more than 200 protein spots were shared among the nuclear matrices, about 18 distinct spots in the nuclear matrices were found characteristic for As2O3 treated cells Conclusions: As2O3 induces apoptosis in K562 cells in a dose and timedependent manner Our results demonstrated that for the detection of the onset of apoptosis, the alteration in the composition of nuclear matrix proteins was a more sensitive indicator than nucleosomal DNA fragmentation test These results indicated that As2O3 might be clinically useful in the treatment of chronic myelogenous leukemia. The changes of nuclear matrix proteins in the treated cells can be used as a useful indicator for this treatment

Pure Total Flavonoids from Citrus paradisi Macfad InduceLeukemia Cell Apoptosis In Vitro

Objective： To investigate the potential effect of pure total flavonoids from Citrus paradisi Macfad peel（PTFC） on the proliferation and apoptosis of human myeloid leukemia cells Kasumi-1, HL-60 and K562, and the underlying mechanisms. Methods： PTFC was extracted from Citrus paradisi Macfad peel and was identified by high performance liquid chromatography. The effect of PTFC on the proliferation and apoptosis of leukemia cells were determined by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide, fluorescent microscopy and flow cytometry, respectively. The effect of PTFC on the expression levels of apoptosis-related regulators was determined by Western blot assay. Results： Treatment with PTFC inhibited leukemia cell proliferation in a dose-and time-dependent manner and triggered Kasumi-1 cell apoptosis. Treatment with PTFC significantly increased the levels of activated poly adenosine diphosphate-ribosepolymerase and caspase-3/-9, but reduced the levels of Mcl-1 expression in Kasumi-1 cells. However, PTFC did not obviously induce HL-60 cell apoptosis. Conclusion： PTFC inhibited leukemia cell proliferation and induced their apoptosis by modulating apoptosisrelated regulator expression in leukemia cells in vitro.

Active compounds-based discoveries about the differentiation and apoptosis of leukemic cells

Acute myeloid leukemia (AML) is a heterogeneous group of hematopoietic malignancies which are characterized by the blockage of hematopoietic cell differentiation with uncontrolled proliferation and/or impaired apoptosis. Over the past 20 years, there has been tremendous progress in the biological, molecular, and cytogenetic aspects of the disease, accompanied by significant advancements in the treatment of AML patients. For example, all-trans retinoic acid (ATRA) and arsenic trioxide (As2O3) have been used clinically for effective treatments of patients with acute promyelocytic leukemia (APL, a unique subtype of AML) through differentiation and/or apoptosis induction. More intriguingly, these active compounds-based chemical biological studies greatly accelerated our understanding on leukemogenesis and targeted therapy of AML patients. Based on some recent findings mainly from our group, this review attempts to summarize the related advances from Chinese researchers.

A facile,branched DNA assay to quantitatively measure glucocorticoid receptor auto-regulation in T-cell acute lymphoblastic leukemia

Glucocorticoid(GC) steroid hormones are used to treat acute lymphoblastic leukemia(ALL) because of their pro-apoptotic effects in hematopoietic cells.However,not all leukemia cells are sensitive to GC,and no assay to stratify patients is available.In the GC-sensitive T-cell ALL cell line CEM-C7,auto-up-regulation of RNA transcripts for the glucocorticoid receptor(GR) correlates with increased apoptotic response.This study aimed to determine if a facile assay of GR transcript levels might be promising for stratifying ALL patients into hormone-sensitive and hormone-resistant populations.The GR transcript profiles of various lymphoid cell lines and 4 bone marrow samples from patients with T-cell ALL were analyzed using both an optimized branched DNA(bDNA) assay and a real-time quantitative reverse transcription-polymerase chain reaction assay.There were significant correlations between both assay platforms when measuring total GR(exon 5/6) transcripts in various cell lines and patient samples,but not for a probe set that detects a specific,low abundance GR transcript(exon 1A3).Our results suggest that the bDNA platform is reproducible and precise when measuring total GR transcripts and,with further development,may ultimately offer a simple clinical assay to aid in the prediction of GC-sensitivity in ALL patients.