共轭亚油酸对人胃腺癌细胞侵袭能力的影响及其作用机制

研究c9,t11-共轭亚油酸 (CLA)对人胃腺癌细胞 (SGC 790 1)侵袭能力的影响 ,探讨其抑制肿瘤转移的可能机理。用 0、2 5、5 0、10 0和 2 0 0 μmol LCLA处理细胞 2 4h后 ,分别用重组基底膜侵袭实验评价癌细胞侵袭能力 ;PAGE底物酶谱方法检测Ⅳ型胶原酶活性 ;RT PCR方法检测SGC 790 1细胞TIMP 1和TIMP 2mR NA表达。研究结果表明 :c9,t11 CLA处理后 ,SGC 790 1细胞侵袭重组基底膜的能力下降、SGC 790 1细胞培养上清中的Ⅳ型胶原酶活性降低、SGC 790 1细胞中TIMP 1和TIMP 2mRNA的表达增加。因此 ,c9,t11 CLA抑制SGC 790 1细胞侵袭重组基底膜 ,并且c9,t11 CLA的抗侵袭活性与降低肿瘤细胞培养上清中Ⅳ型胶原酶活性和诱导肿瘤细胞TIMP 1和TIMP 2mRNA的表达等有关     

共轭亚油酸诱导人胃腺癌细胞(SGC-7901)凋亡的作用

目的 研究共轭亚油酸单体（c9,t11-CLA)诱导人体胃腺癌细胞（SGC－7901）凋亡作用。方法 采用细胞生长曲线,凋亡细胞的荧光显微镜、电镜观察,流式细胞光度术的检测以及P53蛋白表达方法。结果 显示出c9,t11-CLA对SGC－7901细胞有明显的抑制作用,并可诱导SGC－7901细胞产生凋亡,并随着c9,t11-CLA浓度的增加,细胞凋亡率逐渐增加;而P53蛋白表达则随着c9,t11-CLA浓度的增加呈逐渐降低的趋势。结论 这可能是c9,t11-CLA抑制肿瘤细胞机制之一。     

环氧合酶-2在c9,t11-共轭亚油酸抑制肿瘤细胞转移中的作用

目的 研究c9,t11-共轭亚油酸（c9,t11-CLA）抑制人胃腺癌细胞（SGC-7901）转移作用与亚油酸代谢途径中限速酶环氧合酶-2（COX-2）的关系。方法采用体外细胞培养方法,用COX-2的选择性抑制剂NS．398抑制SGC-7901细胞中COX-2的活性,再加入200、100、50和25μmol／L浓度的c9,t11-CLA,利用重组基底膜侵袭实验、黏附实验、趋向运动实验检测c9,t11-CLA抑制肿瘤细胞转移的作用与COX-2的关系。结果与NS-398组比较,NS-398＋100Ixmol／Lc9,t11-CLA和NS-398＋200μmol／L c9,t11-CLA对SGC-7901细胞的侵袭有明显的抑制作用,穿过膜的细胞数分别为48．7±1．5（F=14．309,P=0．000）和43．7±4．0（F=19．005,P=0．000）;NS-398＋200μmol／L c9,t11-CLA组能显著降低SGC-7901细胞对基质成分层粘连蛋白、纤维粘连蛋白和基质胶的黏附作用,所测吸光度值（A值）分别为0．052±0．011,0．058±0．008（F=3．063,P=0．021）和0．042±0．004（F=6．692,P=0．001;F=11．999,P=0．000）;NS-398＋200ixmol／L c9,t11-CLA对SGC-7901细胞的趋向运动能力无明显的抑制作用（F=1．380,P=0．276）,其中NS-398＋2001xmol／L c9,t11-CLA组细胞数为26．6±3．4。结论 c9,t11-CLA具有抑制SGC-7901细胞体外侵袭能力、黏附能力和趋向运动能力,这种抑制作用可能与COX-2途径有关。     

共轭亚油酸对肿瘤细胞亚油酸代谢途径中限速酶的影响

目的采用体外细胞培养方法,研究不同浓度c9,t11-共轭亚油酸(c9,t11-CLA)对人胃腺癌细胞(SGC-7901)中亚油酸代谢途径的限速酶的影响。方法用200、100、50和25μmol／L浓度的c9,t11-CLA处理SGC-7901细胞24h,四甲基偶氮唑盐实验检测c9,t11-CLA对SGC-7901细胞增殖的抑制作用,采用逆转录聚合酶链反应检测c9,t11-CLA对SGC-7901细胞中亚油酸代谢途径的Δ6-脱氢酶、△5-脱氢酶、环氧合酶(COX)-1、COX-2和5-脂氧合酶(5-LOX)mRNA表达的影响。结果在200、100、50和25μmol／L浓度时,c9,t11-CLA对SGC-7901增殖的抑制率分别为54．3％、20．5％、10．5％、2．93％;均可下调COX-2mRNA的表达,上调Δ6-脱氢酶、COX-1mRNA的表达,但对Δ5-脱氢酶和5-LOXmRNA表达的影响不显著。结论c9,t11-CLA可通过调节Δ6-脱氢酶和COX的表达抑制肿瘤细胞的增殖,说明c9,t11-CLA通过影响亚油酸代谢途径中限速酶的基因表达而改变类二十碳烷酸的形成,推测c9,t11-CLA影响肿瘤细胞中亚油酸代谢途径的限速酶是其发挥抗癌活性的另一作用机制。     

β-紫罗兰酮抑制SGC-7901细胞潜在的转移作用

目的观察β紫罗兰酮对人胃腺癌细胞(SGC7901)潜在转移的影响。方法采用细胞生长曲线,酶谱法和RTPCR技术,我们检查了不同浓度(25、50、100和200μmolL)β紫罗兰酮对SGC7901细胞生长,IV明胶酶的活性(MMP2和MMP9),nm23H1基因和金属蛋白酶抑制剂(TIMP1和TIMP2)在SGC7901细胞表达情况。β紫罗兰酮处理时间为24小时和48小时。结果β紫罗兰酮可抑制SGC7901细胞增殖。用不同浓度的β紫罗兰酮处理SGC7901细胞8天的抑制率分别为25.93%、28.21%、74.36%和90.11%。β紫罗兰酮作用于SGC7901细胞的IC50值为89μmolL。β紫罗兰酮不影响SGC7901细胞的基质金属蛋白酶2(MMP2)和基质金属蛋白酶9(MMP9)的活性。然而,β紫罗兰酮可明显地促进nm23H1基因、TIMP1和TIMP2的表达,呈现剂量-反应关系。结论β紫罗兰酮可抑制SGC7901细胞的生长和增殖。可能通过上调nm23H1,TIMP1和TIMP2来影响SGC7901细胞潜在的转移。然而,β紫罗兰酮对SGC7901细胞的IV型明胶酶活性没有影响,因而,β紫罗兰酮抑制SGC7901细胞的转移需要进一步研究。     

共轭亚油酸对人胃腺癌细胞中环氧合酶的影响

目的采用体外细胞培养方法,研究不同浓度c9,t11-共轭亚油酸(CLA)对人胃腺癌细胞(SGC-7901)的亚油酸代谢途径中限速酶-环氧合酶(COX)表达的影响.方法采用逆转录聚合酶链反应(RT-PCR)和蛋白免疫印迹(Western blot)方法检测不同浓度c9,t11-CLA处理后的SGC-7901细胞中环氧合酶(COX)-1、(COX)-2mRNA和蛋白的表达.结果在200,100,50和25μmol/L浓度时,c9,t11-CLA均可下调COX-2 mRNA和蛋白的表达,与共轭亚油酸(CLA)浓度呈负相关;上调COX-1 mRNA的表达,并与CLA浓度呈正相关.结论 c9,t11-CLA的抗癌活性与其影响COX的表达有关.     

共轭亚油酸抑制人胃腺癌细胞体外侵袭作用

目的 采用体外细胞培养技术，模拟体内肿瘤转移过程，研究c9，t11—共轭亚油酸(CLA)对肿瘤细胞侵袭及侵袭相关特性的影响。方法 用0，25，50，100和200μmol／LCLA处理SGC—7901人胃腺癌细胞24h后，分别进行重组基底膜侵袭试验、趋向性运动实验和粘附试验研究CLA对侵袭、运动和粘附能力的影响。结果 在200，100和50μmol／L浓度时，c9，t11—CLA对肿瘤细胞侵袭重组基底膜的抑制率分别为53．7％，40．9％和29．3％。同时，c9，t11—CLA处理后的肿瘤细胞与细胞外基质的粘附能力降低，但对肿瘤细胞趋化运动能力的影响不明显。结论 c9，t11—CLA可降低肿瘤细胞的体外侵袭能力，改变某些侵袭相关性质。     

共轭亚油酸对人乳腺癌细胞生长的抑制作用

目的 研究共轭亚油酸（c9,t11-CLA)对人乳腺癌细胞（MCF－7）生长的影响。方法 采用细胞核分裂指数、细胞生长曲线、细胞集落形成试验、^3H-TdR掺入试验和软琼脂培养方法,所设剂量（μmol/L）为25,50,100,200,以96％乙醇为溶剂对照。结果 在细胞核分裂指数、细胞生长曲线和细胞集落形成试验中,可见c9,t11-CLA对MCF－7细胞生长有明显的抑制作用,其作用于MCF－7细胞8d后的抑制率（％）分别为27．18、35．43、91．05和92．86;在^3H-TdR掺入试验中,可见随着c9,t11-CLA剂量的增加,^3H-TdR掺入到MCF－7细胞中明显的减少,与阴性对照组相比差异有显性;由软琼脂培养试验结果可见,随着c9,t11-CLA剂量的增加,MCF－7细胞的集落形成逐渐降低,除了25 μmol/L剂量组外与阴性对照组相比差异有显性。结论 c9,t11-CLA对MCF－7细胞的生长有明显的抑制作用。     

Bel7402肝癌细胞中共轭亚油酸异构体通过不同机制下调COX-2表达

[目的]采用体外细胞培养方法,研究c9,t11-CLA和t10,c12-CLA对肝癌细胞Bel7402的COX-2表达的影响和机制。[方法]采用逆转录聚合酶链反应(RT-PCR)和蛋白免疫印迹(Westernblot)方法检测c9,t11-CLA和t10,c12-CLA处理后的Bel7402细胞中COX-2 mRNA和蛋白质的表达以及PPARγ配体罗格列酮和GW9662对COX-2蛋白水平的影响。[结果]在100μmol/L的浓度下,c9,t11-CLA和t10,c12-CLA都可以降低COX-2mRNA和蛋白质的表达,罗格列酮可以下调COX-2蛋白水平,而PPARγ抑制性配体GW9662可以逆转c9,t11-CLA对于COX-2蛋白水平的下调作用,但是对于t10,c12-CLA的下调作用则没有影响。[结论]两种异构体对COX-2表达的下调作用很可能具有不同的机制。     

莱菔硫烷抑制人胃癌SGC7901细胞增殖及其诱导凋亡分子流行病学研究

目的研究莱菔硫烷（sulforaphane,SFN）在体外对人胃癌细胞SGC7901的增殖抑制作用,探讨SFN诱导细胞凋亡的分子机理。方法以SFN和人胃癌细胞SGC7901为研究对象。采用四甲基偶氮唑盐比色法观察不同浓度SFN对细胞增殖的抑制影响,AO/EB双重染色法与透射电镜进行形态学变化观察,琼脂糖凝胶电泳观察细胞凋亡状态下的DNA变化,RT-PCR检测细胞p21基因mRNA表达。结果 50～150μmol/L浓度范围的SFN对SGC7901细胞的增殖有明显的抑制作用。AO/EB染色结果显示SFN诱导SGC7901细胞凋亡发生形态学上改变。DNA琼脂糖凝胶电泳显示细胞经SFN（100μmol/L、150μmol/L）处理24 h后可见＂梯形＂DNA碎片条带。RT-PCR结果显示50μmol/L SFN能够诱导p21基因mRNA的表达增强。透射电镜观察到SFN作用SGC7901细胞48 h后出现核固缩等早期凋亡镜下改变。结论 SFN能抑制SGC7901细胞的增殖并诱导SGC7901细胞凋亡,可在翻译和转录水平上调p21的表达,其分子机理可能与调控p21基因存在关系。     

共轭亚油酸对正常动物细胞和人体肿瘤细胞间通讯功能的影响

为探讨c9,t11-共轭亚油酸 (CLA)的抑癌作用可能机制 ,在促癌物 (TPA)存在下 ,对正常细胞(CHL)以及人体肿瘤细胞 (SGC 790 1细胞和MCF 7细胞 )的细胞间隙连接通讯功能 (GJIC)的影响 ,采用划痕标记染料示踪技术 (SLDT) ;c9,t11 CLA剂量为 2 5 (mol L ,5 0 (mol L ,10 0 (mol L和 2 0 0 (mol L ,阴性对照为乙醇。结果显示 ,c9,t11 CLA可明显地提高TPA对CHL细胞的GJIC的抑制效应 ,当c9,t11 CLA浓度为 2 0 0 (mol L作用 48h时 ,细胞间隙通讯功能基本上与阴性对照组相近 ;当用c9,t11 CLA作用SGC 790 1细胞和MCF 7细胞2 4h和 48h时 ,可见 (2 4h 10 0 μmol L的MCF 7细胞 ) 2 4h 2 0 0 μmol L和 48h 10 0、2 0 0 μmol L剂量组的肿瘤细胞有一定的细胞间隙通讯功能。提示c9,t11 CLA可提高SGC 790 1细胞和MCF 7细胞的GJIC的功能 ,并且不同程度的拮抗TPA对CHL细胞GJIC的抑制效应     

环氧合酶-2在c9,t11-共轭亚油酸抑制胃腺癌细胞增殖中的作用

目的　采用体外细胞培养方法,研究不同浓度c9,t11 共轭亚油酸对人胃腺癌细胞(SGC- 790 1)的亚油酸代谢途径中限速酶———环氧合酶(COX -2 )及其产物前列腺素E2 (PGE2 )的影响。方法　采用逆转录聚合酶链反应(RT- PCR)和Westernblot方法检测不同浓度c9,t11 CLA处理后的SGC 790 1细胞中COX- 2mRNA和蛋白的表达,放射免疫方法检测细胞分泌的PGE2 浓度。结果　在2 5、5 0、10 0和2 0 0 μmol L浓度时,c9,t11 CLA均可下调COX 2mRNA和蛋白的表达,同时降低细胞中PGE2 的分泌。结论　环氧合酶2是c9,t11 CLA抑制肿瘤细胞增殖的作用靶点。     

Lycopene inhibits cell migration and invasion and upregulates Nm23-H1 in a highly invasive hepatocarcinoma, SK-Hep-1 cells

The carotenoid lycopene has been associated with decreased risks of several types of cancer, such as prostate cancer and hepatoma. Tumor metastasis is the most important cause of cancer death. Although lycopene was shown to inhibit metastasis, the mechanism underlying this action is not well understood. Here, we tested the possibility that lycopene may inhibit cancer cell metastasis by upregulating the expression of nm23-H1, a metastasis suppressor gene, in SK-Hep-1 cells, a highly invasive hepatoma cell line, and we determined migration and invasion activities and the expression of nm23-H1 protein and mRNA. We showed that lycopene inhibited SK-Hep-1 migration and invasion in a bell-shaped manner, with the highest effect at 5 micromol/L (91 and 63% inhibition for migration and invasion, respectively; P < 0.05). At the same test level (10 micromol/L), lycopene was much more effective than beta-carotene in reducing cell invasion (by approximately 870%). In contrast to the effects on migration and invasion, lycopene enhanced nm23-H1 expression at both the protein and mRNA levels; the effects were also bell shaped, and at 5 micromol/L, lycopene enhanced nm23-H1 protein and mRNA expressions by 220 +/- 33 and 153 +/- 22% (P < 0.01), respectively. These bell-shaped effects of lycopene may be related to autoxidation of lycopene at elevated concentrations (> or =10 micromol/L). Significant correlations existed between nm23-H1 protein expression and migration (r2= 0.78, P < 0.001) and between nm23-H1 protein expression and invasion (r2= 0.84, P < 0.001) in lycopene-treated SK-Hep-1 cells. We conclude that lycopene has significant antimigration and anti-invasion activity, and that this effect is associated with its induction of nm23-H1 expression.     

Cis-9,trans-11-conjugated linoleic acid inhibits allergic sensitization and airway inflammation via a PPARgamma-related mechanism in mice

Milk consumption from early childhood on has been found to be inversely correlated with allergic sensitization and the onset of bronchial asthma. We tested whether cis-9,trans-11-conjugated linoleic acid (c9,t11-CLA), naturally occurring in milk fat, may prevent allergic sensitization and inhibit airway inflammation in a murine asthma model. BALB/c mice were fed a diet enriched in 1 wt% of c9,t11-CLA or a control diet 7 d prior to and for 32 d during sensitization [d 1 and 14, 100 mg/L ovalbumin (OVA) in adjuvant vs. PBS] and airway challenges (d 28-30, 1% OVA in PBS vs. PBS). Subgroups of mice were coadministered 20 micromol/L of the selective PPARgamma antagonist GW9662 during each OVA challenge. C9,t11-CLA feeding resulted in significantly reduced IgE production and allergen-induced in vivo airway hyperresponsiveness. Further, less mucous plugging of segmental bronchi and significantly reduced interleukin-5 and eosinophils were determined in bronchoalveolar lavage fluids of c9,t11-CLA-fed mice. C9,t11-CLA feeding prevented the downregulation of PPARgamma mRNA in the lung tissues observed after allergen sensitization and airway challenges in control mice. The inhibitory effects of c9,t11-CLA on airway inflammation were partially prevented by coadministration of GW9962. Further, c9,t11-CLA feeding resulted in a significantly lower concentration of the eicosanoid precursor, arachidonic acid, in tissue lipids. These findings demonstrate that dietary c9,t11-CLA can reduce allergic airway inflammation, most likely via a PPARgamma-related mechanism and by reducing eicosanoid precursors. They give new insights into the fatty acid-mediated mechanism of immunomodulation and may represent a step toward an attractive novel strategy in the dietary prevention and treatment of allergic asthma.     

Antiproliferative effects of conjugated linoleic acid on human colon adenocarcinoma cell line Caco-2

Conjugated linoleic acid (CLA) reduces body fat reserves, and reduces atherogenesis and type II diabetes in animal experiments. It has been reported that CLA have isomeric-specificity, such as c9, t11 CLA with anticancer activity. The antiproliferative effects of two isomers of CLA (c9, t11-CLA, t9, t11-CLA) and their mixture on the human colon adenocarcinoma cell line Caco-2 were investigated in this paper. Caco-2 were incubated in serum-free medium. The antiproliferative effects of different concentrations (0, 25, 50, 100, 200 micromol/L) of linoleic acid (LA), c9, t11-CLA, t9, t11-CLA (the purity of LA and CLA was 96%) and a mixture of c9, t11-CLA and t9, t11- CLA (1:1 v/v) on caco-2 in various action time (1d, 2d, 3d, 4d) were tested in the present study. The antiproliferative effects of four substances in the same concentration and with the same action time were compared. All substances tested could inhibit Caco-2 cell proliferation. The higher anti-proliferation activity in the four materials is the mixture of CLA, then is t9,t11-CLA, c9,t11-CLA, and linoleic acid respectively. The activity is closely related to treatment time and concentration. The isomer t9, t11-CLA itself was found to have antiproliferative activity.