β-连环素在白血病细胞株的异常定位研究

β-连环素是Wnt信号通路关键的信号传递子，其在细胞的异常定位引起下游靶基因的转录是多种实体肿瘤发生的原因之一。由于造血细胞缺少典型的黏着连接（adherens junction，AJ），因此对β-连环素在血液肿瘤的表达及定位并无较多的研究。本研究探讨4种常见的白血病细胞株（Daudi，Jurkat，K562和Thp-1）中β-连环素蛋白的定位及β-连环素基因mRNA的表达水平，了解血液肿瘤中是否有β-连环素蛋白的定位异常，以期发现白血病新的发生机制，为寻找新的特异治疗靶点提供线索。用免疫细胞化学法检测β-连环素在白血病细胞系中的定位，用实时定量RT-PCR法测定β-连环素mRNA表达水平。结果表明：4种白血病细胞株有两种（Jurkat、Thp-1）存在β-连环素的异常定位，且β-连环素mRNA表达增高，但在Jurkat和Thp-1细胞中的β-连环素mRNA低于Daudi和K562细胞。这4种白血病细胞株中β-连环素基因的mRNA表达水平与其异常定位无相关性。结论：β-连环素定位异常可能参与部分血液肿瘤的发生，引起β-连环素定位异常的机制并不是发生在转录水平。     

PHI对Burkitt淋巴瘤Daudi细胞株组蛋白甲基化和乙酰化调控的实验研究

本研究观察异硫氰酸苯己酯(PHI)在体外对Burkitt淋巴瘤Daudi细胞株的作用及对淋巴瘤细胞表观遗传学调控的影响,初步探讨其可能的机制。用流式细胞术检测PHI处理后的细胞凋亡率,蛋白免疫印迹法检测PHI处理后的细胞的组蛋白H3、H4乙酰化和H3K4、H3K9甲基化状态改变。结果表明,PHI诱导细胞凋亡并提高组蛋白H3、H4乙酰化水平,组蛋白H3K4甲基化增强,而H3K9甲基化减弱。结论:PHI能上调与转录激活相关的组蛋白H3乙酰化水平及甲基化H3K4,下调转录抑制相关的组蛋白甲基化H3K9,促进肿瘤细胞凋亡,PHI可作为淋巴瘤的靶向治疗药物。     

Trichostatin A Regulates hGCN5 Expression and Cell Cycle on Daudi Cells in vitro

The expression of human general control of amino acid synthesis protein 5 (hGCN5) in human Burkitt's lymphoma Daudi cells in vitro, effects of Trichostatin A (TSA) on cell proliferation and apoptosis and the molecular mechanism of TSA inhibiting proliferation of Daudi cells were investigated. The effects of TSA on the growth of Daudi cells were studied by 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) assay. The effect of TSA on the cell cycle of Daudi cells was assayed by a propidium iodide method. Immunochemistry and Western blot were used to detect the expression of hGCN5. The proliferation of Daudi cells was decreased in TSA-treated group with a 24 h IC50 value of 415.3979μg/L. TSA induced apoptosis of Daudi cells in a time- and dose-dependent manner. Treatment with TSA (200 and 400μg/L) for 24 h, the apoptosis rates of Daudi cells were (14.74±2.04) % and (17.63±1.25) %, respectively. The cell cycle was arrested in G0/G1 phase (50, 100μg/L) and in G2/M phase (200μg/L) by treatment with TSA for 24 h. The expression of hGCN5 protein in Daudi cells was increased in 24 h TSA-treated group by immu-nochemistry and Western blot (P<0.05). It was suggested that TSA as HDACIs could increase the expression of hGCN5 in Daudi cells, and might play an important role in regulating the proliferation and apoptosis of B-NHL cell line Daudi cells.     

干扰素-α1b增强人γδT细胞对Daudi细胞系的细胞毒活性及相关机制

目的探讨干扰素-α1b(IFN-α1b)对人γδT细胞体外杀伤肿瘤细胞的促进作用及其相关机制。方法用IFN-α1b预处理的Daudi细胞作为靶细胞;用IFN-α1b预处理的γδT细胞作为效应细胞;LDH法检测γδT细胞对Daudi细胞的细胞毒活性;ELISA检测效靶细胞混合上清中γδT细胞分泌的颗粒酶B和γ干扰素水平;流式细胞计量技术检测IFN-α1b预处理Daudi细胞表面Fas受体和应激蛋白配体ULBP3/ULBP4的表达,以及γδT细胞表面活化分子CD69和CD25的变化。结果IFN-α1b分别预处理Daudi细胞和γδT细胞都能显著增强γδT细胞对Daudi细胞的细胞毒活性(P<0.0001);IFN-α1b预处理的γδT细胞分泌颗粒酶B和γ干扰素的能力显著提高(P<0.05);IFN-α1b能上调Daudi细胞表面Fas受体和应激配体ULBP4的表达水平,而应激配体ULBP3的表达没有变化;IFN-α1b还能上调γδT细胞表面CD69的表达水平,而CD25的表达没有变化。结论IFN-α1b能通过不同的途径促进人γδT细胞对肿瘤细胞系Daudi细胞的体外细胞毒活性,两者的联用能增强γδT细胞的肿瘤治疗疗效。     

Low density lipoprotein and liposome mediated uptake and cytotoxic effect of N4-octadecyl-1-beta-D-arabinofuranosylcytosine in Daudi lymphoma cells.

Low density lipoprotein (LDL) receptor-mediated uptake and cytotoxic effects of N4-octadecyl-1-beta-D-arabinofuranosylcytosine (NOAC) were studied in Daudi lymphoma cells. NOAC was either incorporated into LDL or liposomes to compare specific and unspecific uptake mechanisms. Binding of LDL to Daudi cells was not altered after NOAC incorporation (K(D) 60 nM). Binding of liposomal NOAC was not saturable with increasing concentrations. Specific binding of NOAC-LDL to Daudi cells was five times higher than to human lymphocytes. LDL receptor binding could be blocked and up- or down-regulated. Co-incubation with colchicine reduced NOAC-LDL uptake by 36%. These results suggested that NOAC-LDL is taken up via the LDL receptor pathway. In an in vitro cytotoxicity test, the IC50 of NOAC-LDL was about 160 microM, whereas with liposomal NOAC the IC50 was 40 microM. Blocking the LDL receptors with empty LDL protected 50% of the cells from NOAC cytotoxicity. The cellular distribution of NOAC-LDL or NOAC-liposomes differed only in the membrane and nuclei fraction with 13% and 6% respectively. Although it is more convenient to prepare NOAC-liposomes as compared to the loading of LDL particles with the drug, the receptor-mediated uptake of NOAC-LDL provides an interesting rationale for the specific delivery of the drug to tumours that express elevated numbers of LDL receptors.     

125I-脱氧尿嘧啶核苷对淋巴瘤细胞Raji和Daudi的杀伤作用

目的 探讨¹²⁵I-脱氧尿嘧啶核苷(¹²⁵I-UdR)在淋巴瘤细胞Raji和Daudi中的特异性摄取及其杀伤效应。方法 测量Raji、Daudi细胞和细胞核在含不同放射性浓度¹²⁵I-UdR的培养液中培养不同时间后的活度;用噻唑蓝(MTT)实验和碘化丙啶(PI)染色周期分析评价¹²⁵I-UdR对Raji和Daudi细胞的杀伤作用。结果 Raji和Daudi细胞摄取¹²⁵I-UdR的量明显高于Na¹²⁵I对照组(P<0.05),在100kBq/ml浓度时,Raji和Daudi细胞摄取¹²⁵I-UdR的量分别为(14 414±95)和(6916±53.69)Bq/10⁶细胞,而对Na¹²⁵I的摄取量分别为(68±3.8)和(324±32.8) Bq/10⁶细胞;细胞和细胞核中¹²⁵I-UdR的量随培养基中¹²⁵I-UdR放射性浓度以及培养时间的增加而增加;¹²⁵I-UdR组的存活分数明显低于Na¹²⁵I对照组(P<0.05),以500kBq/ml浓度培养48h时, Raji和Daudi细胞¹²⁵I-UdR组的存活分数分别为(19.78±1.39)%和(43.17±2.69)%,而Na¹²⁵I组的存活分数分别为(79.10±1.79)%和(80.36±6.12)%;细胞存活分数有随培养基中放射性浓度增加而降低的趋势。结论 ¹²⁵I-UdR可被Raji和Daudi细胞特异性摄取并进入细胞核中,进而杀死细胞,其作用具有明显的时间-效应和剂量-效应关系。     

B细胞非霍奇金淋巴瘤小鼠模型的建立

背景与目的：近年来非霍奇金淋巴瘤（non-Hodgkin’slymphoma,NHL）发病率呈上升趋势,其中侵袭性NHL占了很大的比例,然而传统化疗方案提高NHL疗效的空间有限。本研究旨在建立淋巴瘤小鼠模型,为探讨治疗NHL新方案并研究其药物作用机制提供动物模型。方法：应用人弥漫大B细胞NHL细胞株SU-DHL-4及人Burkitt淋巴瘤细胞株Daudi,经尾静脉注射人SCID小鼠体内．探索建立淋巴瘤小鼠模型的条件及特点。Daudi淋巴瘤小鼠分为对照组及美罗华治疗组．观察小鼠的发病情况及生存时间。结果：SU-DHL-4淋巴瘤小鼠在中位时间39．5d后开始发病,主要表现为精神萎靡、消瘦、竖毛、活动迟缓,于小鼠腹腔、尾部或后肢部位出现肿块,未发现肝脏、脾脏、骨髓等脏器出现淋巴瘤细胞浸润。Daudi淋巴瘤小鼠于中位时间30．5d发病,出现双后肢瘫痪,于瘫痪后9．5d左右死亡。Daudi淋巴瘤小鼠的脏器大多受淋巴瘤细胞的累及,骨髓中出现大量Daudi细胞浸润。美罗华治疗使小鼠骨髓中的Daudi细胞呈现明显的凋亡形态。对照组Daudi淋巴瘤小鼠的中位瘫痪时间及生存时间分别为30．5d及40d,美罗华治疗组的小鼠分别为52．5d及76．5d,美罗华治疗组小鼠的中位瘫痪时间及生存时间显著延长（P〈0．05）。结论：应用SU—DHL-4细胞及Daudi细胞均可以成功建立B细胞NHL小鼠模型。     

Cytoplasmic IgM in leukemic B cells by flow cytometry

The presence of intracellular cytoplasmic immunoglobulin M (IgM) in leukemic cells from patients with acute lymphocytic leukemia (ALL) and chronic lymphocytic leukemia (CLL) was investigated by flow cytometry. The objective of the study was to develop a reproducible flow cytometric method. A Burkitt's lymphoma-derived B-cell line, Daudi, and a pre-B ALL, Nalm-6, served as prototypes. Normal B cells and cells from patients with chronic myelogenous leukemia (CML) were used as negative controls. Cytoplasmic mu was expressed in 77.3 +/- 7.5% (n = 10) of Nalm-6 cells. CALLA+ ALL and CML cells lacked cytoplasmic mu. The surface-membrane immunoglobulin on the viable B cells was blocked with purified goat anti-human IgM. Subsequently, the B cells were fixed in cold absolute methanol and stained with a fluorescein-conjugated goat anti-human IgM to demonstrate cytoplasmic IgM. After the surface-membrane IgM was blocked, normal B cells had no cytoplasmic IgM (0.3-0.5% positive cells) detectable by flow cytometry. However, the peripheral blood lymphocytes from five patients with CLL and the Daudi cells contained cytoplasmic IgM, ranging from 7.8 to 76.7% and 45.7 to 89.3%, respectively. We conclude that cytoplasmic mu in Nalm-6, CLL, and Daudi cells can be easily and rapidly demonstrated by flow cytometry.     

BMT-1抑制急性B淋巴母细胞瘤细胞增殖活力及其机制研究

目的 探讨苯并咪唑衍生物BMT-1对急性B淋巴母细胞瘤细胞增殖活力的影响及其相关机制.方法 采用CCK-8方法测定BMT-1对Daudi、Nalm-6的细胞毒性;采用流式细胞技术方法检测BMT-1对Daudi细胞凋亡及线粒体膜电位的影响;采用Western Blot方法检测Daudi细胞凋亡相关蛋白PARP的表达情况.结果BMT-1对Daudi、Nalm-6细胞具有较强的细胞毒性;BMT-1可诱导Daudi细胞凋亡,引起Daudi细胞线粒体膜电位下降,并可使得Daudi细胞产生PARP蛋白剪切体.结论 BMT-1对B淋巴母细胞瘤具有细胞毒性作用,其关键机制为诱导细胞凋亡和引起线粒体膜电位下降,为BMT-1治疗急性淋巴细胞白血病提供了理论基础.