吐温80合并温热(39°-43℃)对BGC-823人胃癌细胞膜流动性及EPM的影响

BGC-823人胃癌细胞经叶温80合并温热(39℃—43℃)处理后,用DPH作荧光分子探针观察细胞膜流动性的变化,并通过测定细胞电泳率(EPM)观察细胞膜表面电荷的改变,正常人红细胞及包皮成纤维细胞作为正常细胞对照。实验结果表明:常温下肿瘤细胞膜流动性及EPM明显高于正常细胞,吐温80和温热对肿瘤细胞及正常细胞均有促进膜流动性及降低细胞电泳率作用。吐温80合并温热时这种作用显著增加,合并作用41℃60分左右的效应已达到温热43℃100分作用水平,有明显时间效应。冷却后各组有不同程度恢复,但合并作用41℃100分以上各组恢复较慢。正常细胞对温热和吐温80作用的反应明显低于肿瘤细胞。     

肿瘤与正常细胞表面糖链结构的流式细胞术分析

为了比较正常与肿瘤细胞表面的糖链结构差异,凝集素用荧光素标记后作为研究细胞膜糖链结构的探针,采用流式细胞技术在分子水平上分析。结果显示正常与肿瘤肝细胞与同一浓度的凝集素探针结合量有明显的不同。与凝集素ConA-FITC结合后,正常肝细胞的荧光峰较肿瘤肝细胞的荧光峰明显右移;与凝集素WGA-FITC、PHA-FITC结合后,正常肝细胞的荧光峰较肿瘤肝细胞的荧光峰明显左移。由于凝集素可识别特定糖链结构,该方法说明肿瘤肝细胞的糖链结构与正常肝细胞相比具有特征变化,即平分型糖链和唾液酸含量丰富,可能出现偏二天线以及天线数的增加。     

细胞膜脂质流动性的不均一性与细胞分裂动力学的关系

细胞腊脂流动性在不同类属细胞存在着差异,其差异的程度取决于细胞的生理和生化特性。正常淋巴细胞、肺腺癌、肺鳞癌细胞以及结核细胞膜脂流动发生 分别为２．５１７±０．２６７、２２．５５７±３．７７１,３２．８７５±９．７０９和４．０２６±０．７２２。细胞分裂动力学与膜脂质流动性有关系。细胞分裂及其程度是膜脂质流动性差异的物质基础,同时并受细胞膜脂质的组成,脂蛋白生化以及外界因素的ｐＨ、Ｃａ＾２＋等影响,     

二氧化硅及柠檬酸铝对红细胞膜结合水影响的研究

本研究应用等温吸附法和付里埃变换红外光谱技术测定了二氧化硅及柠檬酸铝对红细胞膜结合水的不同影响。结果为,二氧化硅明显降低细胞膜水化度,使膜结合水的ν_OH峰位显著红移,表明其可导致细胞膜脱水。而柠檬酸铝对二氧化硅的这一作用有明显的拮抗效应,即通过提高细胞膜的水化度,可维持细胞膜的正常“水结构”。此外,本文还论讨了二氧化硅诱发细胞膜的脱水作用对细胞中毒的意义,以及柠檬酸铝拮抗作用的机理。     

应用凝集素芯片检测肝癌细胞膜表面糖链变化

利用凝集素糖链特异亲和原理构建对细胞膜表面糖链进行即时检测的凝集素芯片体系,检测肝癌发生过程中细胞膜糖链的变化.从H22细胞系、正常小鼠和肝癌模型鼠肝组织中提取细胞进行荧光标记,激光扫描仪检测凝集素位点捕获的细胞,根据凝集素特异亲和性确定细胞膜表面糖表达谱,显微镜下观察捕获细胞的形态.对凝集素芯片捕获细胞的最佳条件进行探讨,用甘露糖抑制试验、流式细胞仪和不同血型红细胞验证了凝集素捕获细胞的特异性.结果显示:正常和肝癌小鼠肝细胞膜表面糖链存在较大差异,正常组只有PSA、DSL、STL、NPL凝集素位点捕获到细胞,实验组只有LTL和DBA位点没有捕获到细胞,提示小鼠肝癌组织细胞膜表面糖链显著增加,细胞膜上唾液酸、乙酰葡萄糖、乙酰半乳糖、甘露糖和半乳糖糖链表达增加,这些糖链及其相关糖蛋白可能在肝癌的发生和发展中起一定作用.该凝集素芯片有较好的稳定性和特异性,可以对细胞膜表面糖链进行动态、即时、通量的检测,为研究细胞膜表面聚糖在细胞发育和癌变等过程中的变化提供了一个技术平台.     

肝癌细胞67kD层粘连蛋白受体N-糖链结构与功能的变化

探讨肝癌细胞与正常肝细胞 6 7kD层粘连蛋白受体 (6 7LR)N 糖链结构与功能的差异 .采用流式细胞术检测SMMC 772 1肝癌细胞和L 0 2正常肝细胞膜表面 6 7LR的表达 ,并分别从这 2株细胞分离纯化到高亲和力的 6 7LR ,利用凝集素结合分析其糖链结构 ,并用肽 N 糖苷酶水解N 糖链 ,观察糖链在与层粘连蛋白结合过程中的作用 .结果发现 ,L 0 2细胞膜表面 6 7LR表达的阳性率为5 5 3% ,而SMMC 772 1细胞为 34.7% ,这两株细胞 6 7LR与伴刀豆素 (ConA)的结合能力无显著差异 ,但SMMC 772 1细胞的 6 7LR与麦胚凝集素的结合能力明显高于L 0 2细胞的 6 7LR ,说明 2株细胞 6 7LR的糖链结构存在显著差异 .当N 糖链被切除后 ,SMMC 772 1细胞的 6 7LR与层粘连蛋白的结合能力明显下降 ,而L 0 2细胞则没有变化 .这些资料表明 ,SMMC 772 1肝癌细胞和L 0 2正常肝细胞与层粘连蛋白结合能力的差别 ,以及两株细胞的 6 7LR与层粘连蛋白结合能力的不同 ,很可能是由于这两株细胞的层粘连蛋白受体的N 糖链结构不同所引起     

脂肪酸对人肺腺癌细胞膜流动性的影响

脂肪酸是细胞膜正常流动性的主要调节因素之一。本文报导了二种不同转移表型人肺腺细胞与九种不同脂肪酸共孵育后,对其细胞膜流动性的影响。结果表明,不同转移一夫肺腺癌细胞对各种脂肪酸有不同的敏感性,高转移癌细胞Ａｎｉｐ对棕榈酸和花生酸较敏感,而低转移癌细胞ＡＧＺＹ对棕榈烯酸和亚油酸较敏感。     

用超微细胞化学定位技术揭示ATP酶在紫茎泽兰高温适应性中的作用

【背景】外来人侵植物紫茎泽兰自然演化出耐高温种群,其适应机制与各种生理代谢有关。【方法】本文从超微细胞化学水平,对紫茎泽兰抗高温种群、敏感种群ATP酶活性定位,明确其在高温适应性中的作用,试图阐明该草的生态适应机制。【结果】正常情况下,紫茎泽兰ATP酶主要定位于细胞壁及细胞间隙周围的细胞壁表面;经40℃高温处理后,在不同的处理时间下,抗性、敏感种群之间ATP酶的活性表现出明显差异,其中以处理12h时差异最大,具体表现为抗高温种群的ATP酶活性明显高于敏感种群,ATP酶的定位点除细胞壁外,在细胞膜上也呈现大量的分布,而敏感种群在处理12h时的酶活性明显降低,只在细胞壁上有零星的分布。处理24h时,敏感种群叶片已完全萎蔫,细胞结构毁坏,细胞膜破损;而抗高温种群叶片仍然完好,细胞膜上仍有ATP酶分布。【结论与意义】经40℃高温处理后,紫茎泽兰抗高温种群ATP酶活性明显高于敏感种群,初步认为紫茎泽兰对高温的适应性与ATP酶活性相关。本研究为进一步阐明与紫茎泽兰适应性相关的入侵机理提供了资料。     

用超微细胞化学定位技术揭示ATP酶 在紫茎泽兰高温适应性中的作用

【背景】外来入侵植物紫茎泽兰自然演化出耐高温种群,其适应机制与各种生理代谢有关。【方法】本文从超微细胞化学水平,对紫茎泽兰抗高温种群、敏感种群ATP酶活性定位,明确其在高温适应性中的作用,试图阐明该草的生态适应机制。【结果】正常情况下,紫茎泽兰ATP酶主要定位于细胞壁及细胞间隙周围的细胞壁表面;经40 ℃高温处理后,在不同的处理时间下,抗性、敏感种群之间ATP酶的活性表现出明显差异,其中以处理12 h时差异最大,具体表现为抗高温种群的ATP酶活性明显高于敏感种群,ATP酶的定位点除细胞壁外,在细胞膜上也呈现大量的分布,而敏感种群在处理12 h时的酶活性明显降低,只在细胞壁上有零星的分布。处理24 h时,敏感种群叶片已完全萎蔫,细胞结构毁坏,细胞膜破损;而抗高温种群叶片仍然完好,细胞膜上仍有ATP酶分布。【结论与意义】经40 ℃高温处理后,紫茎泽兰抗高温种群ATP酶活性明显高于敏感种群,初步认为紫茎泽兰对高温的适应性与ATP酶活性相关。本研究为进一步阐明与紫茎泽兰适应性相关的入侵机理提供了资料。     

癌细胞膜流动性与蛋白激酶C相关性的初步探讨

细胞膜流动性是细胞的重要物理性质,与细胞功能密切相关。为深入认识细胞膜与细胞功能的关系,研究癌症机理及寻找预防治疗的方法提供新的视角和实验数据,采用荧光漂白后恢复技术检测皮肤癌A431细胞和正常HACAT细胞的膜流动性,同时测定蛋白激酶C的活性及mRNA的表达。通过激光扫描共聚焦显微镜的荧光恢复曲线计算得知A431细胞的荧光恢复率和扩散系数均低于HACAT细胞,即A431细胞膜流动性低于HACAT细胞;而蛋白激酶C活性、mRNA表达量却高于正常细胞。以上差异都有统计学意义（P〈0．05）。由此推断癌细胞膜流动性与蛋白激酶C相互作用、相互影响,彼此之间存在密切的关系。     

酪氨酸对大鼠子宫卵巢和睾丸组织核酸合成的影响

据报道,酪氨酸可能影响生殖机能。本实验证明,酪氨酸对大鼠子宫、卵巢、睾丸和肝脏的 RNA 合成有显著抑制作用,同对照组比较,各组P<0.001;对DNA合成也有抑制性影响,各组P<0.05—0.01。而酪氨酸不影响~3H-UR或~3H-TdR 对心脏、脾脏和肾脏核酸的参入。提示酪氨酸对核酸代谢的影响有器官特异性。实验还比较了酪氨酸、孕酮和放线菌素D 对大鼠子宫和卵巢核酸合成的作用,结果表明,三者对DNA和RNA合成均有抑制效应。提示酪氨酸可能是影响大鼠某些性器官核酸生物合成的因子之一。     

体外肿瘤微血管生成模型的建立

本研究以体外微血管培养模型为基础,用鼠尾胶原包埋大鼠动脉环,并将包埋的动脉环转移到种有人肺癌A549细胞单层的培养皿中,用MCDB 131无血清培养液对动脉环和肿瘤细胞进行共培养,从而建立肿瘤微血管体外生成模型。大鼠动脉环于培养后第3天从血管壁长出微血管芽,第6至10天长成微血管丛,两周后新生微血管开始萎缩;没有肿瘤细胞刺激的条件下,大鼠动脉环新生微血管数量明显减少。结果表明人肺癌A549细胞能够促进血管生成。体外大鼠动脉环肿瘤微血管培养模型操作简单、灵敏度高,适合研究肿瘤血管新生及其机制。     

Design,synthesis, and biological evaluation of a cephalosporin-monohydroguaiaretic acid prodrug activated by a monoclonal antibody-beta-lactamase conjugate

A novel cephalosporin derivative of monohydroguaiaretic acid (cephem-M(3)N, 7) was synthesized and found to possess anticancer activity against human leukemia (K562), breast carcinoma (MCF7), human lung cancer (A549), human colon cancer (Colo205) and pancreatic cancer cells (Capan2 and MiaPaCa2). A tumor targeting fusion protein (dsFv3-beta-lactamase) was also used in conjunction with cephem-based M(3)N 7 and its potency toward K562, MCF7, A549, Colo205, Capan2, and MiaPaCa2 was found to approach that of the free M(3)N (4). In the presence of dsFv3-beta-lactamase, tumor cells were found to be much more susceptible to conjugate 7 than normal human embryonic lung (HEL) cells and normal fibroblasts (Hef522). These notions provide a new approach to the use of nordihydroguaiaretic acid (NDGA) and its derivatives for antitumor therapy.     

Effects of theanine on growth of human lung cancer and leukemia cells as well as migration and invasion of human lung cancer cells

The aim of this study is to investigate the effects of theanine, a tea characteristic amino acid, on human lung cancer and leukemia cells. In the present study, we have demonstrated that theanine suppressed the in vitro and ex vivo growth of human non-small cell lung cancer A549 and leukemia K562 cell lines in dose- and time-dependant manners. In addition, theanine displayed the inhibitory effect on the migration of A549 cells. More importantly, theanine enhanced the anticancer activity of anticancer agents such as trichostatin A (the histone deacetylase inhibitor), berbamine and norcantharidin (the anticancer drugs in China) by strongly reducing the viability and/or migration rate in A549 cells. In addition, theanine significantly suppressed A549 cell invasion. Suppression of A549 cell migration may be one of the important mechanisms of action of theanine against the A549 cell invasion. Our present results suggest that theanine may have the wide therapeutic and/or adjuvant therapeutic application in the treatment of human lung cancer and leukemia.     

内吞适配蛋白Epsin在非小细胞肺癌发生中的作用研究

目的:探讨内吞适配蛋白Epsin在非小细胞肺癌发生中的潜在作用。方法:选择体外培养的人非小细胞肺癌细胞(A549),筛选Epsin 1和Epsin 2 shRNA干扰效率达标的细胞。将裸鼠随机分为3组,每组10只,第1、2组裸鼠分别经胸腔植入人非小细胞肺癌细胞(A549)及epsin表达敲减的A549细胞,第3组注射等量的生理盐水,比较1、2组小鼠肿瘤体积的变化。8周后,处死所有裸鼠,留取肺组织及肿瘤组织,通过免疫荧光染色检测非肿瘤(正常)肺和致瘤性肺组织中的epsin 1和2的蛋白质水平。用实时定量PCR(qRT-PCR)来研究epsin 1和2的基因表达水平。结果:肺肿瘤组织epsin1和2的m RNA和蛋白表达均显著高于正常肺组织中(P0.05)。种植epsin表达敲减的A549细胞裸鼠肿瘤生长速度及体积均大于种植正常A549细胞的裸鼠肿瘤。结论:Epsins表达上调可能促进非小细胞肺癌肿瘤的发生发展,而敲减epsins的表达可能为未来的非小细胞肺癌的治疗提供新的治疗靶点。     

Cadmium transport through type II alveolar cell monolayers: contribution of transcellular and paracellular pathways in the rat ATII and the human A549 cells

Cadmium (CD) transport in alveolar type II (ATII) cells has been studied using two in vitro models widely used to investigate lung function: primary cultures of rat ATII cells and the human cell line A549. Nonlinear regression analyses of the uptake time-course of (109)Cd revealed: a zero-time accumulation, a fast process of accumulation which proceeds within minutes, and a much slower process which takes hours. This three-step mechanism was characterized by different parameter values under dishes-or filter-growth conditions. A higher initial uptake rate (v(i)) and equilibrium accumulation (A(max)) of (109)Cd were found in the rat ATII cells; these differences were not related to a higher level of adsorption onto the external surface of the cell membrane. Specific transport systems of similar capacity but different affinity (threefold higher in rat cells) were characterized. A significant transepithelial transport of (109)Cd, with similar P(coeff) in both cell models, could not be exclusively related to cellular metal release. Results on 3H-mannitol permeability together with (109)Cd efflux data strongly suggest a greater contribution of the paracellular pathways in Cd transport through A549 cell monolayers. These differences in transport properties between the two lung cell models may modify the dose-response curve for Cd toxicity.     

Formation and antiproliferative effect of prostaglandin E(3) from eicosapentaenoic acid in human lung cancer cells

We investigated the formation and pharmacology of prostaglandin E(3) (PGE(3)) derived from fish oil eicosapentaenoic acid (EPA) in human lung cancer A549 cells. Exposure of A549 cells to EPA resulted in the rapid formation and export of PGE(3.) The extracellular ratio of PGE(3) to PGE(2) increased from 0.08 in control cells to 0.8 in cells exposed to EPA within 48 h. Incubation of EPA with cloned ovine or human recombinant cyclooxygenase 2 (COX-2) resulted in 13- and 18-fold greater formation of PGE(3), respectively, than that produced by COX-1. Exposure of A549 cells to 1 microM PGE(3) inhibited cell proliferation by 37.1% (P < 0.05). Exposure of normal human bronchial epithelial (NHBE) cells to PGE(3), however, had no effect. When A549 cells were exposed to EPA (25 microM) or a combination of EPA and celecoxib (a selective COX-2 inhibitor), the inhibitory effect of EPA on the growth of A549 cells was reversed by the presence of celecoxib (at both 5 and 10 microM). This effect appears to be associated with a 50% reduction of PGE(3) formation in cells treated with a combination of EPA and celecoxib compared with cells exposed to EPA alone. These data indicate that exposure of lung cancer cells to EPA results in a decrease in the COX-2-mediated formation of PGE(2), an increase in the level of PGE(3), and PGE(3)-mediated inhibition of tumor cell proliferation.     

Synthesis and Cytotoxicity Evaluation of Panaxadiol Derivatives

In this study, 13 panaxadiol (PD) derivatives were synthesized via reactions with aromatic compounds and amino acids. Following this, the cytotoxicity of these compounds was evaluated against four cancer cell lines (human hepatoma cells HepG‐2, human lung cancer cells A549, human breast cancer cells MCF‐7, and human colon cancer cells HCT‐116) and one normal cell lines (human gastric epithelial cells GES‐1). The results showed that the panaxadiol derivatives 3 , 12 , and 13 showed significant inhibition of cellular proliferation against cancer cells compared with PD, and the panaxadiol derivative 12 had the lowest IC₅₀ value for A549 (IC₅₀=18.91±1.03 μm ). For MCF‐7 cells, most compounds exhibited good inhibition of cellular proliferation, and the panaxadiol derivative 13 showed the strongest inhibitory effect (IC₅₀=8.62±0.23 μm ), which significantly increased the cytotoxicity of PD and was stronger than the positive control (mitomycin). For normal cells, all compounds exhibited low or no toxic effects; thus, these derivatives can be used to develop novel antiproliferative agents.     

Gallic acid-induced lung cancer cell death is accompanied by ROS increase and glutathione depletion

Gallic acid (GA) is generally distributed in a variety of plants and foods, and its various biological effects have been reported. Here, we investigated the effects of GA and/or caspase inhibitors on Calu-6 and A549 lung cancer cells in relation to cell death and reactive oxygen species (ROS). The growths of Calu-6 and A549 cells were diminished with an IC(50) of approximately 30 and 150 μM GA at 24 h, respectively. GA also inhibited the growth of primary human pulmonary fibroblast (HPF) cells with an IC(50) of about 300 μM. GA induced apoptosis and/or necrosis in lung cancer cells, which was accompanied by the loss of mitochondrial membrane potential (MMP, ΔΨ(m)). The percents of MMP (ΔΨ(m)) loss and death cells by GA were lower in A549 cells than in Calu-6 cells. Caspase inhibitors did not significantly rescued lung cancer cells from GA-induced cell death. GA increased ROS levels including O(2) (?-) and induced GSH depletion in both lung cancer cells. Z-VAD (pan-caspase inhibitor) did not decrease ROS levels and GSH depleted cell number in GA-treated lung cancer cells. In conclusion, GA inhibited the growth of lung cancer and normal cells. GA-induced lung cancer cell death was accompanied by ROS increase and GSH depletion.     

Different susceptibility of lung cell lines to inhibitors of tumor promotion and inducers of differentiation

Histologically distinct lung tumor and normal cell lines were treated with a variety of potential inhibitors of cell growth such as inducers of cell differentiation, inhibitors of protein kinase C and inhibitors of tumor promotion. The response was assessed by 3H thymidine incorporation and cloning efficiency. Both phorbol retinoate acetate and mezerein stimulated growth in lung normal cell lines (human fibroblastic PEH cells and rat epithelial TP9 cells) while inhibiting growth in lung tumor cell lines (human small-cell cancer-derived cell line IRSC-10M and adenocarcinoma-derived cell line A549). Likewise, the hydrophobic peptide melittin did not inhibit growth and cloning efficiency of normal cells at 1 microM, a concentration which prevented proliferation in tumor cells. Protein kinase C inhibitors, chlorpromazine, trifluoperazine and 1-(5 isoquinolinylsulfonyl) 2-methylpiperazine, were much more effective on proliferation of IRSC-1OM than of A549 cells. In contrast, the latter cells were more susceptible to anti-promoters such as glycyrrhetic acid, an anti-inflammatory agent, and 3,4',2', 4'-tetrahydroxychalcone or 2,3,5-trimethyl-6 (12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone, two inhibitors of lipoxygenase, a key enzyme in arachidonate metabolism. Our results provide evidence that small-cell carcinoma-derived cells, in contrast with adenocarcinoma-derived cells, are growth-inhibited by protein kinase C inhibitors and poorly dependent on the arachidonate metabolism. This difference in responsiveness suggests that different growth signalling pathways are preferentially triggered in these histologically distinct lung tumor cell lines. As a consequence, the proper susceptibility of tumor cells to phenotype modifiers has to be taken into account in cancer therapy.