四种砷拮抗剂对三氧化二坤诱导的三种粒系白血病细胞凋亡和端粒酶活性的减量调节作用

目的：研究巯基供体N-乙酰兰胱氨酸（NAC）和二巯丁二钠（NDMS）、抗氧化剂过氧化氢酶（CAT）和Ca^2 清除剂（Quin2）对三氧化二砷诱导的三种粒系白血病细胞凋亡和端粒酶活性改变的调控作用。方法：用流式细胞仪和PCR ELISA法分别检测NAC、NDMS、CAT或Quin2与三氧化二砷共同作用于三种粒系白血病细胞后其凋亡和端粒酶活性的变化。结果：三氧化二砷0.6、2.7和8.1μmol/L可分别诱导急性早幼粒细胞白血病细胞株NB4,慢性粒细胞白血病细胞株K562,急性粒细胞白血病细胞株HL-60细胞发生40%-60%的凋亡,同时下调三种细胞的端粒酶活性。NAC4mmol/L,NDMS200μmol/L,CAT80kU/L,Quin 2 20μmol/L不同程度抑制这种凋亡作用,NAC和CAT既可独立降低三种细胞的端粒酶活性,也可促进三氧化二砷对端粒酶的下调作用,而Quin2可抑制K562和HL-60细胞中的这种下调作用。结论：三氧化二砷诱导的三种细胞的凋亡过程涉及了疏基失活、自由基的改变、细胞内Ca^2 浓度改变及端粒酶活性下降,NAC、NDMS、CAT及Quin2可不同程度拮抗三氧化二砷对三种细胞的作用。     

大蒜素对HL-60细胞端粒酶活性的影响

目的 研究大蒜素对人早幼白血病HL-60细胞端粒酶活性的影响。方法 不同浓度的大蒜素作用HL-60细胞后,MTT法测细胞的生长和增殖情况,TRAP-PCR-ELISA法研究细胞端粒酶活性的变化。结果 大蒜素能明显地抑制HL-60细胞的生长,且呈时间、浓度依赖性。不同浓度的大蒜素能下调HL-60细胞的端粒酶活性,且同样呈时间、浓度依赖性。结论 大蒜素可抑制HL-60细胞的端粒酶活性,可能是其诱导HL-60细胞凋亡的重要机制之一。     

MEK抑制剂联合三氧化二砷对髓系白血病细胞凋亡的研究

目的:研究MEK抑制剂PD98059联合三氧化二砷(As2O3)对髓系白血病细胞凋亡的影响及其作用机制。方法:将PD98059、As2O3单独或联合作用于髓系白血病细胞系HL-60、K562细胞,用AnnexinV-FITC法检测细胞凋亡,用流式细胞术检测Bcl-2、Caspapse-3表达。结果:联合组与单用组相比,细胞凋亡率明显增高。Bcl-2在HL-60、K562细胞均高水平表达。As2O3明显抑制HL-60细胞Bcl-2表达,对K562细胞Bcl-2无明显抑制作用。单用PD98059、As2O3及两药合用在诱导HL-60、K562细胞凋亡过程中,活化caspapse-3均明显上升,两药合用较单用PD98059或As2O3活化caspapse-3明显升高。结论:PD98059联合As2O3同时抑制ERK/MAPK和Bcl-2,激活Caspase酶,对HL-60细胞有协同促凋亡效应。两药联合同时靶向作用ERK/MAPK和BCR/ABL,活化Caspase酶,协同诱导K562细胞凋亡。PD98059可增强As2O3对髓系白血病细胞的凋亡诱导作用。     

三氧化二砷对人肺癌A549细胞凋亡及耐药基因表达的影响

目的研究三氧化二砷（As2O3）对人肺癌细胞株的诱导凋亡作用及对耐药基因LRP表达的影响。方法应用人肺腺癌A549细胞株,运用体外细胞培养法、MTT法、流式细胞术检测As2O3对人肺癌细胞株抑制及诱导凋亡作用;用逆转录-聚合酶链反应（RT-PCR）方法检测LRP mRNA的表达。结果As2O3对人肺癌A549细胞具有抑制作用,其抑制率呈时间-剂量依赖关系。不同浓度的As2O3均可诱导凋亡。1．0μmol／L、3．0μmol／L的As2O3可下调LRPmRNA的表达。结论As2O3具有抑制肿瘤细胞生长及诱导细胞凋亡作用,其机制与下调LRPmRNA表达有密切关系。     

砷诱导的肝癌细胞凋亡及端粒酶活性改变

目的：研究三氧化二砷（As2O3)对肝癌细胞凋亡的诱导作用及其机制。方法：1μmol/L As2O3处理培养的人肝癌HCC－9204细胞48h，用形态学观察、细胞超微结构分析和流式细胞仪检测等方法鉴定细胞凋亡。用噻唑蓝（MTT）比色试验观察蛋白质全盛抑制剂放线菌素D对As2O3凋亡诱导作用的影响。用TRAP－PCR－ELISA法检测As2O3处理前后肝癌细胞端粒酶活性的变化情况。结果：1μmol/L As2O3作用48h后，HCC－9204细胞出现了典型的凋亡形态学改变和超微结构变化；流式细胞仪检测到大量Annexin-阳性、PI－阴性细胞、放线菌素D可明显拮抗As2O3的凋亡诱导作用。细胞凋亡发生后端粒酶活性显著降低，A450/A630值从2．874降为0．767。结论：As2O3可以有效诱导肝癌细胞凋亡，端粒酶活性降低可能是其中的机制之一。     

菊苣酸诱导人白血病细胞HL-60凋亡作用及机制研究

目的观察菊苣酸诱导人急性髓系白血病细胞株HL-60凋亡的作用并初步探讨其机制。方法培养HL-60细胞,分别给予终浓度为10¹00μmol·L-1的菊苣酸48 h,检测细胞活性和凋亡、Caspase-3活性以及Bcl-2蛋白表达水平。结果终浓度为10100μmol·L-1的菊苣酸48 h,检测细胞活性和凋亡、Caspase-3活性以及Bcl-2蛋白表达水平。结果终浓度为10¹00μmol·L-1的菊苣酸能呈浓度依赖性降低HL-60细胞增殖活性和增加凋亡,增强Caspase-3活性和下调Bcl-2蛋白表达。结论菊苣酸具有抑制白血病细胞株HL-60增殖活性和诱导其凋亡作用,其机制与降低抗凋亡蛋白Bcl-2表达及增强Caspase-3活性有关。     

青蒿素对K562细胞的增殖抑制作用及其作用机制

目的:探讨青蒿素对急性白血病K562细胞的增殖抑制作用及其作用机制.方法:以不同浓度的青蒿素作用于体外培养的K562细胞,MTT法检测细胞生长抑制率,应用流式细胞仪及Hoechst 33258荧光染色法观察细胞凋亡,TRAP-PCR-ELISA法检测细胞凋亡前后的端粒酶活性.结果:青蒿素可显著降低K562细胞端粒酶活性,抑制细胞生长,诱导细胞发生凋亡,并呈现出明显的量-效与时-效关系.结论:青蒿素能抑制K562细胞的生长并诱导细胞发生调亡,降低细胞端粒酶活性可能是其重要作用机制之一.     

紫杉醇体外诱导人胃癌细胞凋亡及对端粒酶活性的影响

目的　研究紫杉醇对人胃癌细胞诱导凋亡作用及端粒酶活性变化。方法　 0 .0 0 1～ 1μmol/L的紫杉醇处理SGC 790 1细胞后 ,用MTT法测定胃癌细胞的生长抑制率 ,通过形态学观察及流式细胞术检测细胞凋亡率 ,半定量TRAP -银染法测定端粒酶活性变化。结果　不同浓度的紫杉醇对胃癌细胞均有明显抑制作用 ,且呈时间依赖性及剂量依赖性 ,光镜及流式细胞术分析表明 ,0 .0 1μmol/L的紫杉醇处理后 2 4h ,细胞即出现明显的凋亡形态特征及凋亡峰 ,对端粒酶活性的同步检测结果显示 ,紫杉醇在诱导细胞凋亡的同时伴随端粒酶活性下调 ,且随紫杉醇浓度增大 ,抑制作用逐渐增强 ,2 4h酶活性即显著受抑制 ,72h变为阴性。结论　紫杉醇对胃癌细胞具有明显抑制作用 ,诱导细胞凋亡并抑制端粒酶活性可能是其发挥抗癌作用的机制之一 ,端粒酶可作为肿瘤化疗的敏感性指标。     

桂皮醛诱导K562细胞分化增强Mel18表达

目的探讨桂皮醛对慢性髓细胞白血病细胞株k562的诱导分化作用及其机制。方法以低浓度桂皮醛（30μmol/L、60μmol/L）作用于体外培养的K562细胞,流式细胞术检测桂皮醛作用前后K562细胞分化抗原和Mel18表达,westernblot检测K562细胞c-Myc表达。结果低浓度桂皮醛作用后K562细胞表面单核细胞分化抗原CD11b和CD14表达呈剂量依赖性增加,Mel18荧光明显增强,c-Myc表达明显下降。结论低浓度桂皮醛可诱导K562细胞向单核细胞分化,Mel18表达增加在桂皮醛诱导K562细胞分化中发挥重要作用。     

辛伐他汀对K562细胞端粒酶活性及人端粒酶逆转录酶表达的影响

目的探讨辛伐他汀治疗慢性粒细胞白血病可能的作用机制。方法辛伐他汀10和20μmol.L-1与K562细胞作用48或72 h后,用流式细胞术AnnexinⅤ-FITC/PI双染法检测细胞凋亡百分率;提取细胞端粒酶,用PCR-ELISA检测端粒酶活性;实时荧光定量PCR检测人端粒酶逆转录酶(hTERT),c-myc和bcl2-mRNA表达。结果辛伐他汀10和20μmo.lL-1与K562细胞作用48 h后,细胞凋亡率分别为(6.24±0.18)%和(9.41±0.22)%,与对照组(1.88±0.14)%比较明显增加;作用72 h后细胞凋亡率分别为(12.41±0.32)%和(19.08±0.26)%,与对照组(4.20±0.19)%比较明显增加。辛伐他汀10和20μmo.lL-1与K562细胞作用48或72 h后,端粒酶活性,hTERT,c-myc和bcl-2 mRNA表达明显低于对照组。结论辛伐他汀可使K562细胞端粒酶活性降低,其机制可能与下调hTERT mRNA表达有关。     

Establishment and characterization of arsenic trioxide resistant KB/ATO cells

Arsenic trioxide (ATO) is used as a chemotherapeutic agent for the treatment of acute promyelocytic leukemia. However, increasing drug resistance is reducing its efficacy. Therefore, a better understanding of ATO resistance mechanism is required. In this study, we established an ATO-resistant human epidermoid carcinoma cell line, KB/ATO, from its parental KB-3-1 cells. In addition to ATO, KB/ATO cells also exhibited cross-resistance to other anticancer drugs such as cisplatin, antimony potassium tartrate, and 6-mercaptopurine. The arsenic accumulation in KB/ATO cells was significantly lower than that in KB-3-1 cells. Further analysis indicated that neither application of P-glycoprotein inhibitor, breast cancer resistant protein (BCRP) inhibitor, or multidrug resistance protein 1 (MRP1) inhibitor could eliminate ATO resistance. We found that the expression level of ABCB6 was increased in KB/ATO cells. In conclusion, ABCB6 could be an important factor for ATO resistance in KB/ATO cells. The ABCB6 level may serve as a predictive biomarker for the effectiveness of ATO therapy.     

三氧化二砷对人脐静脉内皮细胞作用的研究

目的以人脐静脉内皮细胞作为血管新生内皮细胞的模拟物,通过研究As2O3对人脐静脉内皮细胞的影响,探讨As2O3的抗血管新生作用机制。方法分离和培养人脐静脉内皮细胞,以不同浓度和时间的As2O3和VEGF作用于脐静脉内皮细胞,应用流式细胞技术测定As2O3和VEGF对脐静脉内皮细胞增殖、细胞凋亡和癌基因bcl-2表达的影响。结果As2O3以时间和剂量依赖的方式抑制内皮细胞增殖,促进细胞凋亡,抑制癌基因bcl-2表达,而VEGF可拮抗As2O3的部分作用。结论As2O3可以通过直接作用于内皮细胞而抑制血管新生。     

低剂量砷长期诱导人肝细胞获得耐砷性的实验研究

目的：培养人肝细胞（L-02）耐砷细胞株,为生物体对砷的耐受机制的研究奠定基础。方法：采用人肝细胞（L-02）在含有低剂量亚砷酸钠（NaAsO2）的培养基中长期培养,并设同步对照细胞组,利用噻唑兰（MTT）检测法计算细胞生存率、半数致死量（LDso）及细胞内砷浓度作为反映细胞对砷耐受性改变的指标。结果：细胞经砷诱导6周后,在24h急性砷中毒试验中．实验组细胞对急性染砷表现出明显的耐受性提高,实验组在各浓度下细胞生存率都明显高于同步对照组,实验组LD。为23．1μmol／L,对照组LD50为10．2μmol/L。实验组各浓度下的砷浓度都明显低于同步对照组（P〈0．001）。结论：人正常肝细胞与细菌、真菌、哺乳动物及人前列腺细胞-样在长期低剂量砷诱导下具有可诱导的对砷的耐受性。     

Inorganic arsenic induces necrosis of human CD34-positive haematopoietic stem cells

Inorganic arsenic is a major environmental contaminant known to exert immunosuppressive effects. In this study, we report toxicity of As2O3, a trivalent inorganic form, toward isolated human hematopoietic CD34+ progenitor cells. Our results demonstrate that low concentrations of As2O3 (0.1-5 microM) inhibit in vitro proliferation of CD34+ cells and their differentiation into various hematological cell lineages. These effects were associated with the induction of a necrotic process independent of caspases and likely related to mitochondrial damage. We conclude that As2O3 can impair in vitro human hematopoiesis by decreasing survival of CD34+ progenitor cells.     

Time course of arsenic species in red blood cells of acute promyelocytic leukemia (APL) patients treated with single agent arsenic trioxide

Background:Arsenic trioxide (ATO) is widely applied to treat acute promyelocytic leukemia (APL). To elucidate metabolism and toxicity of arsenic, we analyzed time course of arsenic species in red blood cells (RBCs) of APL patients.

Methods:Nine APL patients received ATO (0.16 mg/kg/day) through 18-h infusion. Blood was collected before daily administration (days 2 to 9), and at different time points on day 8. Inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were detected by HPLC-ICP-MS.

Results:Arsenic species reached C_max at 18 h on day 8. Arsenicals gradually accumulated during days 2 to 9, whereas their percentages remained almost constant. The general trend in red blood cells (RBCs) was iAs > MMA > DMA. MMA was consistently the predominant methylated arsenic metabolite in RBCs. iAs, MMA, and tAs (tAs = iAs + DMA + MMA) concentrations (P < 0.0001), MMA/DMA ratios (P = 0.0016) and iAs% (P = 0.0013) were higher in RBCs than in plasma.

Conclusions:Time course of arsenic species reveal kinetic characteristic of ATO metabolites in RBCs. Arsenic species accumulated with administration frequency. Arsenic species in RBCs were remarkably different from those in plasma. Time course of arsenic species in RBCs is important in ATO clinical application.     

三氧化二砷对小鼠过敏性哮喘的治疗作用及机制

目的 :研究三氧化二砷对小鼠过敏性哮喘的治疗作用及对脾T细胞周期和Bcl 2基因表达的影响。方法 :用卵蛋白建立小鼠过敏性哮喘模型 ,收集肺泡灌洗液 (BALF) ,直接计算白细胞总数和分类 ,双缩脲法检测总蛋白含量 ,应用Medlab生物信号采集系统软件检测小鼠肺功能 ,流式细胞术和免疫荧光法检测脾及BALF中T细胞数、T细胞周期和Bcl 2基因表达的变化。结果 :三氧化二砷可使BALF中总蛋白含量下降 ,白细胞总数减少 ,嗜酸细胞和淋巴细胞减少 ,改善哮喘小鼠肺功能 ;使脾及BALF中T细胞数降低 ;在 1.15mg·kg-1的剂量时可诱导脾T细胞凋亡 ,在 4 .6 0mg·kg-1的剂量时抑制其活化增殖 ;可下调脾T细胞Bcl 2基因表达。结论 :三氧化二砷有平喘作用 ,其作用机制可能与其调节T细胞的激活与凋亡 ,下调Bcl 2基因表达有关。     

三氧化二砷诱导肿瘤细胞凋亡途径的研究

目的　探讨细胞线粒体跨膜电位 (Δψm)和半胱氨酶3(Caspase 3)在三氧化二砷 (As2 O3 )诱导肿瘤细胞凋亡过程中的作用。方法　以Namalwa、SGC790 1和Bcap37细胞为体外模型 ,流式细胞仪检测亚G1期细胞含量和细胞膜磷脂酰丝氨酸 (PS)外翻量等方法鉴定细胞凋亡 ;碘化丙啶 (PI) /Rhodamine(Rh12 3)双染色检测Δψm变化并观察了Caspase 3抑制剂DEVD CHO对As2 O3 诱导肿瘤细胞凋亡的影响。结果　As2 O3 诱导肿瘤细胞凋亡效应与其诱导细胞Δψm下降和Caspase 3活性升高相关 ,抑制Caspase 3活性后As2 O3 使细胞选择坏死通路。结论　As2 O3 可能通过诱导细胞Δψm下降激活Caspase 3并最终使肿瘤细胞凋亡。     

Cancer in experimental animals exposed to arsenic and arsenic compounds

Inorganic arsenic is a ubiquitous environmental contaminant that has long been considered a human carcinogen. Recent studies raise further concern about the metalloid as a major, naturally occurring carcinogen in the environment. However, during this same period it has proven difficult to provide experimental evidence of the carcinogenicity of inorganic arsenic in laboratory animals and, until recently, there was considered to be a lack of clear evidence for carcinogenicity of any arsenical in animals. More recent work with arsenical methylation metabolites and early life exposures to inorganic arsenic has now provided evidence of carcinogenicity in rodents. Given that tens of millions of people worldwide are exposed to potentially unhealthy levels of environmental arsenic, in vivo rodent models of arsenic carcinogenesis are a clear necessity for resolving critical issues, such as mechanisms of action, target tissue specificity, and sensitive subpopulations, and in developing strategies to reduce cancers in exposed human populations. This work reviews the available rodent studies considered relevant to carcinogenic assessment of arsenicals, taking advantage of the most recent review by the International Agency for Research on Cancer (IARC) that has not yet appeared as a full monograph but has been summarized (, IARC Special Report: Policy, Vol. 10. Lyon: IARC Press, 453–454). Many valid studies show that arsenic can interact with other carcinogens/agents to enhance oncogenesis, and help elucidate mechanisms, and these too are summarized in this review. Finally, this body of rodent work is discussed in light of its impact on mechanisms and in the context of the persistent argument that arsenic is not carcinogenic in animals.     

Chronic arsenic poisoning

Symptomatic arsenic poisoning is not often seen in occupational exposure settings. Attempted homicide and deliberate long-term poisoning have resulted in chronic toxicity. Skin pigmentation changes, palmar and plantar hyperkeratoses, gastrointestinal symptoms, anemia, and liver disease are common. Noncirrhotic portal hypertension with bleeding esophageal varices, splenomegaly, and hypersplenism may occur. A metallic taste, gastrointestinal disturbances, and Mee's lines may be seen. Bone marrow depression is common. 'Blackfoot disease' has been associated with arsenic-contaminated drinking water in Taiwan; Raynaud's phenomenon and acrocyanosis also may occur. Large numbers of persons in areas of India, Pakistan, and several other countries have been chronically poisoned from naturally occurring arsenic in ground water. Toxic delirium and encephalopathy can be present. CCA-treated wood (chromated copper arsenate) is not a health risk unless burned in fireplaces or woodstoves. Peripheral neuropathy may also occur. Workplace exposure or chronic ingestion of arsenic-contaminated water or arsenical medications is associated with development of skin, lung, and other cancers. Treatment may incklude the use of chelating agents such as dimercaprol (BAL), dimercaptosuccinic acid (DMSA), and dimercaptopanesulfonic acid (DMPS).