三氧化二砷诱导HL-60细胞凋亡效应及抑制细胞ERK的活性

目的:初步探讨三氧化二砷(arsenic trioxide,As2O3)促进HL-60细胞凋亡及其可能机制.方法:不同浓度的As2O3(0、2.5、5、10 μmol/L)作用于HL-60细胞24h后,MTT法检测细胞增殖,流式细胞术检测细胞凋亡,Western blot检测Caspase-3活化、ERK活性和cyclinD1蛋白的表达,RT-PCR法检测cyclinD1 mRNA的表达.结果:As2O3可抑制HL-60细胞增殖,诱导HL-60细胞的凋亡,并呈浓度依赖性 (P<0.05);As2O3可使HL-60细胞Caspase-3激活,并抑制ERK活性,但不能下调cyclinD1的表达(P>0.05).结论:As2O3能抑制HL-60细胞增殖,并诱导其凋亡,其效应可能与As2O3抑制HL-60细胞ERK活性有关.     

华蟾素对HL-60细胞凋亡诱导作用及与三氧化二砷的协同作用

[目的]观察华蟾素对白血病细胞的凋亡诱导作用及其与三氧化二砷（As2O3)的协同作用。[方法]通过形态学方法、DNA电泳、Annexin V标记法检测华蟾素或（和）As2O3作用后HL-60细胞的凋亡发生情况。[结果]0.0625μg/ml-0.5μg/ml的华蟾素作用48h后，HL－60细胞发生凋亡，并具有一定的量效关系；华蟾素与As2O3合用后对HL－60细胞的凋亡诱导作用明显增强。[结论]华蟾素对白血病细胞具有凋亡诱导作用，并且与As2O3具有协同作用。     

三氧化二砷诱导恶性肿瘤细胞凋亡机制的研究进展

三氧化二砷已广泛应用于白血病和各种实体瘤化学治疗的基础研究和临床实践中。近年来国内外多项研究证实三氧化二砷诱导凋亡是其杀伤肿瘤的主要机制,其分子机制尚未得到系统阐明,本文就其抗凋亡作用机制的研究进展作一综述。     

ERK通路参与的未分化甲状腺癌FRO细胞凋亡过程及三氧化二砷的调控作用研究

目的：探讨三氧化二砷促进未分化甲状腺癌FRO细胞凋亡的机制,为临床治疗提供参考。方法将生长状态良好的未分化甲状腺癌FRO细胞随机分为5组：对照组、U0126（10μM）组、三氧化二砷低剂量（1μM）组、三氧化二砷中剂量（10μM）组、三氧化二砷高剂量（100μM）组。分析各组细胞凋亡蛋白、ERK通路蛋白表达。结果研究发现三氧化二砷能引起未分化甲状腺癌FRO细胞Bax、Caspase-3和Caspase-6蛋白表达增强以及Raf、Ras、MEK、ERK1/2和Bcl-2表达减弱（P﹤0.05）,且高剂量效果比中剂量和低剂量更显著（P﹤0.05）。结论三氧化二砷能有效促进未分化甲状腺癌FRO细胞凋亡,且此过程与其抑制ERK信号转导通路蛋白过表达有关。     

三氧化二砷诱导恶性肿瘤细胞凋亡机制的研究进展

三氧化二砷已广泛应用于白血病和各种实体瘤化学治疗的基础研究和临床实践中。近年来国内外多项研究证实三氧化二砷诱导凋亡是其杀伤肿瘤的主要机制,其分子机制尚未得到系统阐明,本文就其抗凋亡作用机制的研究进展作一综述。     

三氧化二砷诱导肝癌细胞凋亡的初步研究

目的：研究三氧化二砷（Ａｓ２Ｏ３）对肝癌细胞株Ｂｅｌ－７４０２的抑制增殖效应及凋亡诱导作用。方法：采用ＭＴＴ法检测药物对细胞的抑制作用、相差显微镜和电镜观察细胞形态变化、琼脂糖凝胶电泳测定ＤＮＡ Ｌａｄｄｅｒ、流式细胞术检测细胞周期变化。结果：各浓度Ａｓ２Ｏ３组（０．２５～１６μｍｏｌ／Ｌ）均可抑制肝癌细胞增殖,且抑制率具有浓度和时间依赖性,同作用时间呈直线相关,其中浓度组为１０μｍｏｌ／Ｌ）均可抑制肝癌细胞增殖,且抑制率具有浓度和时间依赖性,同作用时间呈直线相关,其中浓度组为１０μｍｏｌ／Ｌ抑制率最大,９６ｈ时达８３．８９％,２μｍｏｌ／Ｌ Ａｓ２Ｏ３以抑制肝癌细胞的增殖为主,但在形态及生化方面未见凋亡改变;１０μｍｏｌ／Ｌ Ａｓ２Ｏ３作用１０ｈ可见形态学变化,４８ｈ可见ＤＮＡ Ｌａｄｄｅｒ出现。流式细胞检查     

三氧化二砷诱导骨髓瘤细胞凋亡机制研究

目的 了解三氧化二砷（As2O3)诱导多发性骨髓瘤细胞（MM）凋亡的可能机制及其与维甲酸和干扰素的相互作用。方法 联合应用As2O3和巯基还原剂（DTT）、谷胱甘肽耗褐剂（BSO）、全反式维甲酸（ATRA）或干扰素（ＩＦＮ－α）处理MM细胞系RPM18226和U266细胞;应用台盼蓝拒染法计数细胞活力,经细胞形态学和流式细胞仪等判定细胞凋亡的程度;通过测定细胞内荧光染料Rhodamine123的色强度分析线粒体跨膜电位（△ψm)。结果 BSO可加强As2O3诱导的RPM18226和U266细胞线粒体△ψm下降和凋亡,而DTT则有部分拮抗的作用,ATRA诱导RPMI8226细胞闻过则喜亡,但它和As2O3之间无协同效尖,ATRA并不诱导U266细胞凋亡。此外,INF-α,既不抑制RPMIS226和U266细胞的生长和活力,也不改变As2O3对这些细胞的作用。结论 As2O3诱导多发性骨髓瘤细胞凋亡和巯基有关,但ATRA干扰素和As2O3无协同效应。     

三氧化二砷诱导人卵巢癌细胞凋亡机制的研究

目的：探讨三氧化二砷（arsenic trioxide,As2O3)诱导人卵巢癌细胞株3AO细胞凋亡的机制。方法：以人卵巢癌细胞株3AO细胞为体外实验对象。通过台盼蓝染色法，测定不同浓度As2O3作用不同时间对3AO细胞的生长抑制率；采用流式细胞仪检测法，通过碘化丙（PI）／罗丹明123（Rhodammine 123,Rh123)双重染色测定3AO细胞线粒体跨膜电位（△ψm) ；通过吖啶橙染色，荧光显微镜观察As2O3作用后3AO细胞的形态变化。结果：As2O3对3AO细胞的生长具有明显的抑制作用，且具有时间与剂量依赖性（P＜0．05）；3.0μmol/L的As2O3作用48h后3AO细胞中PI－Rh123^-细胞与对照组相比，差异有显著性（P＜0．05）；As2O3作用后，3AO细胞呈现典型的凋亡细胞形态特征。结论：As2O3通过诱导凋亡来抑制人卵巢癌细胞株细胞的生长，其机制与线粒体跨膜电位△ψm下降有关。     

谷胱甘肽合成酶抑制剂加强三氧化二砷的凋亡诱导效应

了解巯基在三氧化二砷诱导凋亡效应中的作用。方法γ－谷氨酰半胱氨酸合成酶抑制剂和Ａｓ２Ｏ３共同处理白血病细胞系ＮＢ４、ＨＬ６０、Ｕ９３７、ｊｕｒｋａｔ和淋巴瘤细胞系ｎａｍａｌｗａ,通过流式细胞仪检测细胞线粒体跨膜位和凋亡细胞。结论巯基是Ａｓ２Ｏ３诱导细胞凋亡的重要化学感受器。     

三氧化二砷诱导人卵巢癌细胞凋亡机制的研究

目的 :探讨三氧化二砷 (arsenictrioxide ,As2 O3 )诱导人卵巢癌细胞株 3AO细胞凋亡的机制。方法 :以人卵巢癌细胞株 3AO细胞为体外实验对象。通过台盼蓝染色法 ,测定不同浓度As2 O3 作用不同时间对 3AO细胞的生长抑制率 ;采用流式细胞仪检测法 ,通过碘化丙啶 (PI) /罗丹明 12 3(Rho damine12 3,Rh12 3)双重染色测定 3AO细胞线粒体跨膜电位 (△Ψm) ;通过吖啶橙染色 ,荧光显微镜观察As2 O3 作用后 3AO细胞的形态变化。结果 :As2 O3 对 3AO细胞的生长具有明显的抑制作用 ,且具有时间与剂量依赖性 (P <0 0 5 ) ;3 0 μmol/L的As2 O3 作用 4 8h后 3AO细胞中PI- Rh12 3- 细胞与对照组相比 ,差异有显著性 (P <0 0 5 ) ;As2 O3 作用后 ,3AO细胞呈现典型的凋亡细胞形态特征。结论 :As2 O3 通过诱导凋亡来抑制人卵巢癌细胞株细胞的生长 ,其机制与线粒体跨膜电位△Ψm下降有关。     

Arsenic trioxide downregulates telomerase activity in HL-60 cells

Telomeres are the specialized nucleoproteincomplexes at the physical ends of eukaryoticchromosomes[1]. Telomere length decreases along with increasing cycles of cell divisions. Telomere shortening has therefore been proposed to play a role in cellular senescence. Telomerase is a protein-RNA enzyme complex that adds a six-base DNA sequence (TTAGGG) to the ends of chromosomes and thereby prevents their shortening. This enzyme is specifically activated in most malignant tumors but is usuall…     

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 cells 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. This work was supported by a grant from the Science and Technology Committee of Sichuan Province (No. 2008JY0029-1).     

Arsenic trioxide

Arsenic has been used as a medicinal for thousands of years. Several reports from China relative to its use mainly in acute promyelocytic leukemia, especially from the Shanghai group, has caused a resurgence in the investigation of the drug in the management of malignancies with focus on malignancies of hematologic origin. Arsenic is eliminated by many routes (urine, feces, sweat, milk, hair, skin, and lungs), although most is ultimately excreted in urine. Multiple myeloma is characterized by the clonal proliferation of malignant plasma cells in the bone marrow associated with bone loss, renal disease, and immunodeficiency. Preclinical evidence suggests an immunologic mechanism behind the therapeutic effects of As₂O₃ on myeloma cells. This appears to be achieved by a marked increase in lymphokine-activated killers mediated killing and up-modulation of CD38 and Cd54, two molecules involved in cell-cell interactions. Moreover, As₂O₃ alone or administered with ascorbic acid may provide a novel therapy for lymphoproliferative disorders. Preliminary clinical data in relapsed/refractory multiple myeloma suggest that As₂O₃ does have a role in the management of multiple myeloma; however, preclinical data show that the addition of ascorbic acid, and using As₂O₃ in combination with other active chemotherapeutic agents will enhance its role in managing the disease, and this is probably the position the drug will occupy in the armamentarium against myeloma.     

Arsenic trioxide induces oxidative stress,DNA damage,and mitochondrial pathway of apoptosis in human leukemia (HL-60) cells

Background

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML), which accounts for approximately 10% of all acute myloid leukemia cases. It is a blood cancer that is formed by chromosomal mutation. Each year in the United States, APL affects about 1,500 patients of all age groups and causes approximately 1.2% of cancer deaths. Arsenic trioxide (ATO) has been used successfully for treatment of APL patients, and both induction and consolidated therapy have resulted in complete remission. Recently published studies from our laboratory have demonstrated that ATO pharmacology as an anti-leukemic drug is associated with cytotoxic and genotoxic effects in leukemia cells.

Methods

In the present study, we further investigated the detailed molecular mechanism of ATO-mediated intrinsic pathway of apoptosis; using HL-60 cells as a test model. Oxidative stress was assessed by spectrophotometric measurements of MDA and GSH levels while genotoxicity was determined by single cell gel electrophoresis (Comet assay). Apoptosis pathway was analyzed by Western blot analysis of Bax, Bcl2 and caspase 3 expression, as well as immunocytochemistry and confocal imaging of Bax and Cyt c translocation and mitochondrial membrane potential depolarization.

Results

ATO significantly (p < 0.05) induces oxidative stress, DNA damage, and caspase 3 activityin HL-60 cells in a dose-dependent manner. It also activated the intrinsic pathway of apoptosis by significantly modulating (p < 0.05) the expression and translocation of apoptotic molecules and decreasing the mitochondrial membrane potential in leukemia cells.

Conclusion

Taken together, our research demonstrated that ATO induces mitochondrial pathway of apoptosis in HL-60 cells. This apoptotic signaling is modulated via oxidative stress, DNA damage, and change in mitochondrial membrane potential, translocation and upregulation of apoptotic proteins leading programmed cell death.     

三氧化二砷诱导K562/ADM细胞凋亡中mdr1和Survivin基因的表达

目的:探讨三氧化二砷(arsenic trioxide,ATO)诱导白血病多药耐药K562/ADM细胞凋亡过程中mdr1和Sur vivin基因的表达变化。方法:应用噻唑蓝(MTT)比色法检测细胞增殖活性,细胞形态学、DNA片段化和细胞周期改变观察K562/ADM细胞凋亡;流式细胞术(FCM)测定Caspase3活性;RT PCR检测Sur vivin和mdr1mRNA的表达。结果:ATO可抑制K562/ADM细胞增殖,并出现典型凋亡形态改变,DNA电泳出现梯状条带(DNAladder);细胞周期分析显示,2～5μmol/LATO作用24h,细胞被阻滞在G2/M期,G1期细胞减少;72h时Sub G1期细胞分别为25.6%和52.9%。2～5μmol/LATO作用24～48h,mdr1mRNA和SurvivinmRNA表达水平明显下降,48h时mdr1mRNA的抑制率分别为83.4%和87.8%,SurvivinmRNA为21.6%和68.6%。ATO作用后,Caspase3活性明显增强,活化Caspase3由17.9%增加到47.4%。结论:ATO降低K562/ADM细胞mdr1和Survivin基因表达,解除P gp和Survivin对Caspases的抑制效应而促进耐药细胞凋亡。     

以Bcl-2为靶标siRNA提高HL-60细胞对三氧化二砷敏感性的探讨

Objective To study whether the small-interference RNA (siRNA) targeting against Bcl-2 gene can enhance sensitivity of HL-60 cell to arsenic trioxide. Methods SiRNA was transferred into the HL-60 cells. At 6 h after transfection, the cells were cultured with arsenic trioxide. The cell growth of the HL-60 cells was detected using MTT at 24, 48 and 72 h, respectively.The levels of the Bcl-2 protein and reactive oxygen species (ROS), as well as of the membrane potential of the mitochondrion were determined by flow cytometry. Results The Bcl-2 siRNA significantly increased the inhibitory action of arsenic trioxide on growth of HL-60 cells. The combination of siRNA with arsenic trioxide resulted in decrease of the Bcl-2 protein level and increase of the ROS level, as well as significant descending of the membrane potential of mitochondrion of HL-60 (P ＜ 0.05).Conclusion The siRNAtargeting Bcl-2 can increase the sensitivity of the HL-60 leukemia cells to arsenic trioxide by inhibiting the expression of Bcl-2 protein.