磷酰肌醇—3激酶途径在慢性髓细胞白血病细胞增殖和抗凋亡中的作用

目的 探讨磷酰肌醇—3激酶途径在K562和HL60细胞增殖中的作用。方法 用磷酰肌醇—3激酶(PI3K)特异抑制剂Wortmannin抑制PI3K活性，观察K562细胞和HL60细胞增殖能力的变化。结果 显示K562和HL60细胞在培养24小时、48小时、72小时的增殖抑制率分别为41．33％、57．46％、65．85％和32．14％、17．14％、13．14％。生长曲线显示Wortmannin可显著抑制K562细胞的增殖，而对HL60细胞增殖无明显影响。结论 Wortmannin可以通过抑制PI3K通路抑制K562细胞的增殖。     

磷酰肌醇-3激酶途径与bcr/abl基因介导的白血病细胞增殖和抗凋亡信号传导

目的探讨磷酰肌醇-3激酶途径在K562、NB4和HL60细胞增殖和凋亡抗性中的不同作用。方法短期培养法直接法G显带检测K562细胞和CML患者骨髓原代细胞的染色体核型,RQ-PCR检测K562细胞和CML患者骨髓原代细胞的bcr/abl基因;用磷酰肌醇-3激酶特异抑制剂渥曼青霉素(WT)抑制磷酰肌醇-3激酶活性,经细胞生长曲线测定、半固体集落形成实验、流式细胞膜联蛋白V标记技术检测细胞凋亡百分比和凋亡指数。观察K562、NB4和HL60细胞增殖能力及凋亡抗性的变化。统计学采用t检验。结果K562细胞G显带检出Ph染色体,RQ-PCR检测K562细胞存在bcr/abl基因;与标准Ph染色体表达的CML患者骨髓原代细胞的bcr/abl基因完全吻合;K562、NB4和HL60细胞在24h、48h、72h的增殖抑制率分别为41.33%、57.46%、65.85%和26.29%、5.51%、2.10%及32.14%、17.14%、13.14%。生长曲线显示WT抑制磷酰肌醇-3激酶途径可显著抑制K562细胞的增殖(P<0.05),而对NB4和HL60细胞增殖无明显影响(P>0.05)。K562、NB4和HL60细胞加和不...     

bcl-2反义肽核酸诱导HL-60 K562细胞凋亡

目的　探讨不同结构的反义药物对HL 60、K562细胞系生物学活性的影响。方法　应用细胞计数、细胞形态观察和流式细胞术观察并比较反义肽核酸和反义寡核苷酸对白血病细胞HL 60、K562生物学活性的影响。结果　 1 0 μmol/L靶向bcl 2mRNA蛋白编码区的反义肽核酸能有效地抑制HL 60、K562细胞的生长、下调bcl 2蛋白的水平及诱导细胞凋亡。 1 0 μmol/L针对bcl 2mRNA同样靶点的反义肽核酸和寡核苷酸作用HL 60和K562细胞 72h ,反义肽核酸仍表现出较强的促细胞凋亡的作用 ,而反义寡核苷酸诱导细胞凋亡的作用则有所下降。结论　反义bcl 2肽核酸能诱导HL 60、K562细胞的凋亡 ,比反义寡核苷酸有更好的反义作用。     

毛兰素诱导人白血病HL—60细胞的凋亡

目的：研究毛兰素对HL－60细胞增殖的抑制作用,探讨其诱导细胞凋亡的机制。方法：用MTT比色法测定了毛兰素对HL－60细胞增殖的抑制作用：应用荧光显微镜、透射电镜、DNA电泳及流式细胞仪观察了药物对细胞凋亡的诱导作用,并用免疫组化的方法从基因水平阐述了凋亡的发生。结果：毛兰素20－81．9nmol/L在72h内显著抑制HL－60细胞增殖,作用24h后,对HL－60细胞的IC50为38nmol/L,而阳性对照药长春新碱对HL－60细胞的IC50为101nmol/L,前者明显优于后者;形态学观察可见凋亡的特征性改变;琼脂糖电泳出现典型的DNA“ladder”;流式细胞仪结果表明细胞被阻滞于G2／M期;免疫组化可见bcl-2表达下降,bax表达升高。结论：毛兰素显著抑制HL－60细胞的生长,该抑制作用可能是通过诱导细胞凋亡和改变HL－60细胞bcl-2和bax基因的表达而实现的。     

柴胡皂甙d（SSd）对不同白血病细胞增殖的抑制作用

目的 研究从柴胡中提取的单体成分柴胡皂甙d对K562、HL－60细胞增殖是否有影响。方法 分别用不同浓度的SSd作用于K562、HL－60细胞株，于不同时间段分别计数其平均细胞数，并绘制相应生长曲线计算平均抑制率。药物作用后24、36、48小时，计算分裂指数。结果 在用药后K562、HL－60细胞的细胞数、分裂指数均下降，下降幅度与剂量呈正相关，且K562下降幅度较大。结论 SSd能抑制K562、HL－60细胞增殖，这种抑制作用呈时间和剂量依赖关系（P＜0.05）并且与细胞株种类相关。     

冬凌草甲素对K562细胞端粒酶活性调控及细胞周期的影响

目的研究冬凌草甲素(ORI)对K562细胞端粒酶活性及其细胞周期的影响。方法免疫细胞化学法测定K562细胞中hTERT和C-myc蛋白的表达；TRAP-PCR-ELISA法检测了端粒酶活性变化；流式细胞仪测定细胞周期各时相百分比。结果用3.43 μmol·L^-1 ORI作用于Ｋ562细胞48 h后，hTERT和C-myc蛋白的表达降低；在一定的浓度范围内，ORI可下调K562细胞端粒酶活性。同时细胞周期各时相分布发生变化，G₀/G₁期或G₂/M期细胞增多，S期细胞减少。结论ORI可下调K562细胞的端粒酶活性，其机制可能与其细胞周期阻滞作用及抑制hTERT和C-myc蛋白的表达有关。     

二氢青蒿素下调粒系白血病细胞转铁蛋白受体表达

通过建立常铁HL60和K562细胞以及富铁K562细胞体外模型，研究二氢青蒿素对粒系白血病细胞转铁蛋白受体(transferrin receptor，TfR)的调控作用。采用流式细胞术检测二氢青蒿素对粒系白血病细胞TfR密度的调控作用，Western blotting和RT-PCR法检测二氢青蒿素对粒系白血病细胞TfR表达的调控作用，原子吸收分光光度法检测二氢青蒿素对常铁和富铁K562细胞铁含量的影响，以及MTT法和台盼蓝拒染法分析二氢青蒿素对粒系白血病细胞增殖的作用。结果显示，二氢青蒿素能显著降低常铁HL60和K562细胞TfR的密度和下调TfR蛋白的表达，且呈浓度和时间依赖性，并能有效地抑制细胞增殖，IC₅₀值分别为1.74和11.33 μmol·L^-1。二氢青蒿素对富铁K562细胞的TfR蛋白和mRNA表达能进一步增强下调作用，与常铁培养组比较，10 μmol·L^-1二氢青蒿素对富铁K562细胞TfR蛋白和TfR mRNA表达量分别下调了28.1%(P<0.01)和26.2%(P<0.05)，并能显著下降富铁K562细胞铁的含量(P<0.05)，更有效地抑制富铁K562细胞增殖。由此可见，二氢青蒿素能下调粒系白血病细胞TfR密度以及TfR蛋白和mRNA的表达，有效抑制常铁HL60和K562细胞的增殖，对富铁K562细胞增殖的抑制作用能进一步增强。     

4-［4″-(2″, 2″, 6″, 6″-四甲基-1″-哌啶氮氧自由基)氨基］-4′-去甲表鬼臼毒素对K562/ADM细胞的抑制作用

目的 比较4-［4″-(2″, 2″, 6″, 6″-四甲基-1″-哌啶氮氧自由基)氨基］-4′-去甲表鬼臼毒素（GP-7）对多药耐药人慢性粒细胞白血病K562的多柔比星耐药株细胞（K562/ADM细胞）的抑制作用是否优于依托泊苷。方法 以依托泊苷和K562细胞为对照，用不同浓度GP-7处理K562/ADM细胞不同时间，MTT比色法测定细胞增殖，流式细胞仪测定细胞周期和细胞凋亡率，普通光学显微镜观察细胞凋亡形态，琼脂糖凝胶电泳观察细胞DNA凋亡性降解。结果 8～128 mol·L^-1 GP-7处理48 h或64 μmol·L^-1 GP-7处理24～72 h，GP-7对K562/ADM细胞的增殖抑制呈剂量依赖性（r=0.947，P＜0.05)和时间依赖性(r=0.999，P＜0.01)。GP-7及依托泊苷对K562/ADM的IC₅₀分别为(45.9±1.8)及(68.7±4.6)μmol·L^-1；64 μmol·L^-1 GP-7作用48 h可使G₂/M期细胞明显增多，相同情况下依托泊苷则使S期细胞明显增多；GP-7可引起K562/ADM和K562细胞凋亡，但其引起的K562/ADM和K562细胞凋亡率与依托泊苷无明显差异；GP-7可引起K562/ADM和K562细胞典型的凋亡形态学变化和DNA凋亡性降解，但GP-7引起的K562/ADM细胞DNA凋亡性降解弱于K562细胞；128及256 μmol·L^-1 GP-7或依托泊苷处理K562/ADM和K562细胞48 h，GP-7诱导DNA凋亡性降解的作用强于依托泊苷，但32和64 μmol·L^-1时作用则相反。结论 GP-7可抑制多药耐药白血病细胞株K562/ADM的增殖,诱导细胞凋亡。GP-7抑制多药耐药白血病细胞株K562/ADM的作用优于依托泊苷。     

氨肽酶抑制剂—Bestatin诱导人白血病细胞凋亡的研究

目的：研究国产氨肽酶N抑制剂Bestatin对人白血病细胞的作用及其机理,方法：应用MTT比色法观察bestatin对细胞的生长抑制作用,流式细胞仪检测细胞表面CD13的表达,光学显微镜观察细胞形态结构的改变。DNA凝胶电泳,DNA片段原位末端标记及流式细胞仪（FCM）检测,以分析细胞凋亡,Rhodamin(Rh)123染色后,FCM检测细胞线粒体跨膜电位,结果：（1）Bestatin明显抑制HL60细胞的生长,半数抑制（IC50）约为13．03ug/ml,而K562细胞的敏感性较差,IC50大于400ug/ml,其抑制作用均呈剂量－时间效应关系。：（2）典型的细胞形态改变,DNA片段化,DNA末端原位标记的检出及ＦＣＭ结果,均证实bstatin能诱导白血病细胞的凋亡,（３） 10ug/ml bestatin作用２４h即可明显诱导ＨＬ６０细胞凋亡,Ｋ５６２细胞的凋亡敏感性显著低于HL60细胞,两者凋亡率均呈剂量和时间依赖性。（4）经bestatin作用后,细胞出现G1期阻滞;（5）经bestatin处理的HL60细胞出现线粒体跨膜电位（Δφm）下降,结论：Bestatin能抑制K562,HL60细胞生长,诱导凋亡是其机制之一,该效应可能与线粒体Δφm下降有关。 wtetrg ,xlw     

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。     

Immunological changes in the intestines and skin after senna administration

Abstract

Context: It has been reported that chronic sennoside use is associated with the development of melanosis coli, colonic adenoma, and/or carcinomas.

Objectives: In this study, we investigated the immunological changes in the colon and skin after the administration of senna.

Materials and methods: In this study, we investigated the colon and epidermis of C57/BL6j mice after a single administration of 10?mg/kg of senna [Cassia angustifolia (Caesalpiniaceae); 3, 6, 12, and 24?h after administration] and after repeated once per week administrations (on days 3, 5, 7, 14, and 21 of administration). The LD₅₀ and ED₅₀ of senna used in this experiment were 165?mg/kg and 13?g/kg, respectively.

Results: We demonstrated that the DOPA-positive cells in the colon increased at 12?h after single administration and were further increased from at 5–28?d after repeated administration. We also studied the physiological changes of the small intestine using the charcoal meal test. We found that there was a tendency for peristalsis to be inhibited after repeated senna administration. In the epidermis, we investigated the number of Langerhans cells, because they are important immune cells of the skin. The number of these cells decreased, especially after repeated administration.

Discussion and conclusion: The present findings suggested that it is necessary to pay attention to not only the intestine but also the skin, during long-term senna treatment.     

干细胞样SP细胞研究进展

摘要： 干细胞样 SP 细胞是近年来在很多正常组织和恶性肿瘤组织及细胞系中发现的一种具有不同程度分化潜能和自我更新能力的细胞群体。虽然 SP 细胞在总体细胞中所占比例很低, 但这部分具有干细胞特性的细胞在干细胞以及肿瘤干细胞研究方面起着越来越重要的作用。本文综述了 SP 细胞的发现、 生物学特性、 与肿瘤干细胞之间的关系以及 SP 细胞的未来临床应用等。最后对 SP 细胞的发展进行了展望。     

干细胞研究进展

干细胞不仅存在于胚胎发育时期 ,而且在成体内也广泛分布于各种不同组织器官的特定部位。在胚胎时期干细胞的功能主要是参与机体的发育 ,成年后则对维持组织器官的新陈代谢有重要作用。随着胚胎干细胞 ,神经干细胞等方面研究的不断深入 ,有关干细胞的研究已日益成为一个全球性的热点。本文仅就其进展做一简要综述。     

Stem cell-derived hepatocytes and their use in toxicology

Better prediction of safety risk and understanding of mechanism of action of drug candidates remain a major challenge in order to prevent late stage attrition. Continuous efforts are made to improve and develop new models, especially in some areas such as hepatotoxicity. Besides primary hepatocytes and transformed liver cell lines, stem cells either isolated from embryos or adult tissues or obtained by reprogramming somatic cells are emerging as a new potential source of unlimited numbers of hepatocytes. Presently, only hepatocyte-like cells expressing low levels of liver-specific markers, especially drug metabolizing and detoxifying enzymes, are usually obtained, making them still unsuitable as metabolically competent cells for toxicity studies. The only exceptions are some hepatoma cell lines, particularly the HepaRG cell line that can differentiate from a bipotent progenitor stage to attain the functional capacity of normal adult hepatocytes in primary culture without losing the indefinite growth property of transformed cells. Since the research field on stem cells is growing fast marked advances might be expected in the next future.     

Analysis of receptor-G protein interactions in permeabilized cells

Receptor-induced binding of the stable GTP analogue, guanosine 5-[-thio]triphosphate (GTP [S]), to guanine nucleotide-binding regulatory proteins (G proteins) was measured in various permeabilized cells. In myeloid differentiated human leukemia (HL-60) cells, permeabilized with either digitonin, streptolysin O or Staphylococcus aureus -toxin, binding of GTP [S] induced by three distinct chemoattractant receptors was observed. The extent of receptor-stimulated GTP [S] binding (maximally about 2-fold) was independent of the type of permeabilizing agent used. In human erythroleukemia cells permeabilized with digitonin, agonist activation of thrombin and neuropeptide Y receptors increased GTP [S] binding by 1.8- and 1.5-fold, respectively. Finally, in adherently grown human embryonic kidney cells permeabilized with digitonin, activation of the stably expressed human muscarinic m3 receptor increased GTP[S] binding by about 1.6-fold. In digitonin-permeabilized HL-60 cells, a quantitative analysis of formyl peptide receptors and interacting G proteins was performed. About 50,000 formyl peptide receptors per cell were detected. Agonist binding to these receptors was fully sensitive to regulation by guanine nucleotides and pertussis toxin. The number of high-affinity GTP [S] binding sites, most likely representing heterotrimeric G proteins, was calculated to be about 670,000 per cell. Stimulation of formyl peptide receptors led to the activation of about 130,000 of high-affinity GTP [S] binding sites, indicating a ratio of about three activated G proteins per one agonist-activated receptor.Overall, this study indicates that receptor-stimulated GTP [S] binding to G proteins in permeabilized cells is a sensitive and rapid method for analyzing receptor-G protein interactions, which can be applied to a variety of cultured cells and for various receptor systems.     

Metabolic characterization of cell systems used in in vitro toxicology testing: Lung cell system BEAS-2B as a working example

The bioactivation of pro-toxicants is the biological process through which some chemicals are metabolized into reactive metabolites. Therefore, in vitro toxicological evaluation should ideally be conducted in cell systems retaining adequate metabolic competency and relevant to the route of exposure. The respiratory tract is the primary route of exposure to inhaled pro-toxicants and lung-derived BEAS-2B cell line has been considered as a potentially suitable model for in vitro toxicology testing. However, its metabolic activity has not been characterized.We performed a gene expression analysis for 41 metabolism-related genes and compared the profile with liver- and lung-derived cell lines (HepaRG, HepG2 and A549). To confirm that mRNA expression was associated with the corresponding enzyme activity, we used a series of metabolic substrates of CYPs (CYP1A1/1B1, CYP1A2, CYP2A6/2A13 and CYP2E1) known to bioactivate inhaled pro-toxicants. CYP activities were compared between BEAS-2B, HepaRG, HepG2, and A549 cells and published literature on primary bronchial epithelium cells (HBEC).We found that in contrast to HBEC, BEAS-2B and A549 have limited CYP activity which was in agreement with their CYP gene expression profile. Control cell lines such as HepG2 and HepaRG were metabolically active for the tested CYPs. We recommend that similar strategies can be used to select suitable cell systems in the context of pro-toxicant assessment.     

Recent Developments in Cell-based Immune Therapy for Neuroblastoma

Neuroblastoma (NB) is a common and aggressive tumor of early childhood. To date, treatment with chemotherapy, surgery, and radiation therapy has resulted in suboptimal outcomes in those with advanced disease. Immune-based treatments hold promise for patients with recurrent or advanced NB. Here, recent preclinical studies and early stage (phase I) clinical trials using cellular therapeutic approaches for NB are reviewed, including studies of natural killer cells, γδ T cells, chimeric receptor expressing T cells, dendritic cells, and allogeneic hematopoietic cell transplant. This work was supported in part by grants from the Children’s Cancer Research Fund and the Minnesota Medical Foundation.     

Role of the microenvironment in tumor growth and in refractoriness/resistance to anti-angiogenic therapies

Angiogenesis is critical for growth of many tumor types and the development of anti-angiogenic agents opened a new era in cancer therapy. However, similar to other anti-cancer therapies, inherent/acquired resistance to anti-angiogenic drugs may occur in cancer patients leading to disease recurrence. Recent studies in several experimental models suggest that both tumor and non-tumor (stromal) cell types may be involved in the reduced responsiveness to the treatments. The current review focuses on the role of stromal cells in tumor growth and in refractoriness to anti-VEGF treatment.     

肺干细胞的研究进展

肺干细胞(lung stem cells)是指在特定条件下能分化为功能性肺组织,在维持肺组织更新和肺损伤修复中起着重要作用的细胞。近年来对肺干细胞的研究已取得了很大的进展,该文就肺干细胞的来源、分离方法、应用以及肺癌干细胞等方面的研究进展作如下综述。     

Sulfur amino acid deprivation in cadmium chloride toxicity in hepatoma cells

The aim of this study was to investigate the effect of individual sulfur amino acid deprivation in cadmium chloride toxicity. HTC cells were deprived of cystine and/or methionine for 12 h and then exposed to CdCl₂ for 12 h. HepG2 cells were deprived of cystine for 3 and 5 h and exposed to CdCl₂ for 3 h. In addition HepG2 cells were deprived of methionine for 12 h and then exposed to CdCl₂ for 5 and 12 h. Our results indicate that only cystine depletion increased cadmium toxicity in HTC cells but not in HepG2 cells as indicated by the neutral red assay. This effect was due to glutathione depletion as indicated by measurement of intracellular glutathione in HTC cells following deprivation of cystine. Methionine depletion had only a slight effect on the viability of HepG2 cells.