大豆异黄酮抑制人乳腺癌细胞生长及作用机制研究

采用体外细胞培养的方法 ,探讨大豆异黄酮对体外培养的人乳腺癌MCF - 7细胞生长的作用及作用机制。结果表明 ,大豆异黄酮抑制MCF - 7细胞生长 ,诱导MCF - 7细胞凋亡。蛋白水平检测表明大豆异黄酮可使MCF - 7细胞iNOS表达升高。结果提示大豆异黄酮抑制MCF - 7细胞生长 ,诱导细胞凋亡 ,并主要是通过调节iNOS基因表达实现的     

RNA沉默Slug基因对人乳腺癌细胞株MCF-7侵袭及血管生成的影响

目的:研究Slug-shRNA-1干扰Slug基因对MCF-7侵袭潜力及诱导血管内皮细胞形成管腔能力的影响。方法:通过体外侵袭模型,测定MCF-7通过Slug-shRNA-1作用于Slug基因后穿透Matrigel的潜力;应用MCF-7与人脐静脉内皮细胞(HUVEC)双室联合培养技术,观察MCF-7通过Slug-shRNA-1作用于Slug基因后诱导HUVEC形成管腔能力的影响。结果:siRNA-Slug作用于Slug基因后能明显降低MCF-7穿透Matrigel的能力(P<0.05),抑制MCF-7诱导HUVEC形成管腔样结构的能力(P<0.05)。结论:Slug-shRNA-1作用于Slug基因后能明显降低MCF-7的侵袭潜力,抑制MCF-7诱导管腔形成能力。     

金雀异黄素对人乳腺癌细胞MCF-7生长影响

目的 观察金雀异黄素在低雌激素水平情况下对雌激素依赖阳性人乳腺癌细胞MCF-7的生长影响.方法 采用四甲基偶氮噻唑蓝(MTT)法检测细胞增殖,流式细胞术分析细胞周期分布情况,磷脂结合蛋白V/碘化丙啶(AnnexinV/PI)联合双染法检测细胞凋亡,间接免疫荧光法测定雌激素调节蛋白(prcsenilin2,PS2>)的表达.结果 当MCF-7细胞经过去雌激素处理以后,与对照组相比,金雀异黄素在5×10-7～10-5mol/L时可以促进细胞增殖,G0>/G1>期细胞向S期推进,PS2>蛋白表达增加,但是抑制细胞凋亡作用并不明显.结论 金雀异黄素在低雌激素水平情况下可以促进人乳腺癌细胞MCF-7的细胞增殖、DNA合成以及PS2>蛋白的表达,具有一定的雌激素样作用.     

金雀异黄素对DDT类农药诱导乳腺癌细胞增殖效应的抑制作用

目的 探讨金雀异黄素( genistein,Gen)与DDT类有机氯农药(o,p’-DDT,p,p’-DDT和p,p’-DDE)联合作用对乳腺癌(MCF-7)细胞增殖效应的抑制作用.方法 取处于对数生长期的MCF-7细胞,分别加入含100 μmol/Gen 和0.1 μmol/L o,p’-DDT、0.1μmol/Lp,p’-DDT、10 μmol/Lp,p’-DDE单独作用组以及100 μmol/L Gen +0.1 μmol/Lo,p’-DDT、100 μmol/L Gen +0.1 μmol/Lp,p’-DDT、100 μmol/L Gen+10 μmol/LP,p’-DDE的培养基,并设溶剂对照(0.1％无水乙醇)组和雌激素对照(10-3 μmol/L雌二醇)组.培养48 h后,采用噻唑蓝(MTT)实验检测MCF-7细胞的增殖情况.结果 与溶剂对照相比,100 μmol/L的Gen作用组MCF-7细胞的增殖率下降,0.1 μmo/L的o,p’-DDT作用组MCF-7细胞的增殖率升高,差异均有统计学意义(P＜0.05).与相应DDT类农药单独组相比,Gen+o,p’-DDT、Gen+p,p’-DDT联合作用组MCF-7细胞的增殖率明显下降,差异均有统计学意义(P＜0.05).结论 Gen能够抑制DDT类农药诱导的MCF-7细胞增殖效应.     

用MCF-7细胞检测多氯联苯拟雌激素样活性

目的观察多氯联苯（PCB）对MCF-7细胞增殖及生长曲线的影响。方法选用多氯联苯（1254）进行MCF-7人乳腺癌细胞增殖实验。结果PCB组细胞增殖指数均明显高于溶剂对照组，10ng／LPCB可诱导MCF-7细胞最大增殖（P〈Q01）。生长曲线分析也显示，PCB、E2生长曲线明显上移，有明显刺激MCF-7细胞增殖的类雌激素活性。结论提示PCB具有拟雌激素样活性。     

二氯二苯二氯乙烯的类雌激素活性的实验研究

目的研究二氯二苯二氯乙烯(DDE)的类雌激素活性对人乳腺癌细胞株MCF-7增殖的影响。方法采用了体外MCF-7细胞增殖试验检测了DDE(3×10-5、3×10-6、3×10-7、3×10-8、3×10-9 mol/L)的类雌激素活性,并用生长曲线分析对其作用机制进行了初步探讨。结果3×10-6 mol/LDDE染毒组吸光度值高于溶剂对照组且MST-7细胞增殖的生长曲线与10-9 mol/L17β-雌二醇染毒组相似。结论DDE具有刺激MCF-7细胞增殖的类雌激素活性,其机制可能与17β-雌二醇相同。     

FTY720对人乳腺癌MCF-7细胞、喉癌Hep-2细胞增殖的影响

目的:探讨FTY720抑制人乳腺癌MCF-7细胞和喉癌Hep-2细胞增殖作用。方法:将人乳腺癌MCF-7细胞和喉癌Hep-2细胞用不同浓度FTY720作用48 h,MTT法检测细胞活性,流式细胞术检测其对细胞周期及凋亡率的影响。结果:MTT结果显示,FTY720对乳腺癌MCF-7细胞和喉癌Hep-2细胞增殖均有抑制作用,而且对喉癌Hep-2细胞抑制作用的浓度依赖性高于对乳腺癌细胞的作用;流式细胞术检测结果显示,FTY720可将乳腺癌MCF-7细胞阻滞于G1期,将喉癌Hep-2细胞阻滞于G2/M期,并明显促进乳腺癌MCF-7细胞凋亡。结论:一定浓度的FTY720能明显抑制体外培养的乳腺癌和喉癌细胞增殖,调节其细胞周期,诱导乳腺癌MCF-7细胞凋亡。     

MS-275与表阿霉素合用对乳腺癌MCF-7细胞的影响

目的:研究组蛋白去乙酰化酶抑制剂MS-275和表阿霉素联用诱导乳腺癌细胞株MCF-7细胞周期阻滞和细胞凋亡的影响,并对其机制进行初步探讨。方法:体外培养人乳腺癌细胞株MCF-7;应用MTT法检测表阿霉素单用以及和MS-275联用对细胞存活率的影响;应用流式细胞仪检测细胞凋亡率;Western blot分析P21、P53蛋白表达的差异。结果:MS-275和表阿霉素合用较表阿霉素单用能明显降低乳腺癌细胞的存活率,增加细胞的凋亡率,具有剂量的依赖性。单用表阿霉素可以使P21、P53蛋白上调,MS-275和表阿霉素合用较单用两种蛋白上调更加明显。结论:MS-275和表阿霉素合用较单用能增加对乳腺癌细胞MCF-7的细胞毒性。其机制可能和MS-275预处理使染色质的构象发生改变,加强了表阿霉素诱导的P21和P53的表达有关。     

Beta-carotene is accumulated, metabolized, and possibly converted to retinol in human breast carcinoma cells (MCF-7)

The aims of the present study were to investigate the uptake, accumulation, and metabolism of beta-carotene by the human breast carcinoma cell line MCF-7. Beta-carotene uptake was time- and dose-dependent, and independent of cell polarity. Beta-carotene accumulation in cells was linear as a function of its concentration in medium (1.3-4.1 micromol/L). It was accompanied by increasing amounts of retinol, which accumulated in cells following a sigmoid pattern, and by other four putative metabolites. Beta-apocarotenals, epoxides, endoperoxides, retinal, retinoic acid, and retinyl esters were not detected in cell extracts. Beta-carotene and its metabolites did not induce alterations in cell morphology or subcellular localization of epithelial mucins. Beta-carotene and retinol were released from cells that had previously accumulated beta-carotene, and were further incubated in beta-carotene- and retinol-free medium, but intracellular retinol content remained constant whereas beta-carotene decreased. In conclusion, beta-carotene added to culture medium in physiological concentrations (1-6 micromol/L) is taken up and metabolized in MCF-7 cells, and is possibly converted to retinol.     

The effect of seal oil on paclitaxel induced cytotoxicity and apoptosis in breast carcinoma MCF-7 and MDA-MB-231 cell lines

Some studies have suggested that omega-3 polyunsaturated fatty acids (PUFAs) have an inhibitory effect on the growth of cancer cells and therefore have the potential to increase the efficacy of cancer chemotherapeutic drugs. Considering that omega-3 PUFAs are present abundantly in harp seal oil, we investigated the effect of seal oil on the cytotoxicity and apoptosis induced by paclitaxel in 2 breast cancer cell lines, MCF-7 and MDA-MB-231, respectively. Cytotoxicity evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that the concentration of paclitaxel that is required for 50% inhibition of cell growth in the presence of seal oil was significantly lower than that of paclitaxel alone. Apoptosis assessment based on morphological changes and DNA fragmentation results indicated that more cells treated with paclitaxel in combination with seal oil underwent apoptosis than with paclitaxel alone. Western blot analysis showed that the expression of B cell lymphoma-2 (Bcl-2) protein, an apoptosis inhibitory protein, in both cell lines was decreased more significant by paclitaxel in combination with seal oil than by paclitaxel alone. In addition, seal oil alone was found to induce apoptosis in both cell lines tested, which appeared to be due to the increased intracellular lipid peroxides produced. It is therefore concluded that paclitaxel in combination with seal oil demonstrated enhanced cytotoxicity and apoptosis in MCF-7 and MDA-MB-231 cells compared to paclitaxel alone, and the use of seal oil may be beneficial in the treatment of breast cancer.     

1800 MHz射频电磁场对人乳腺癌细胞蛋白质表达的影响

目的采用高通量的蛋白质组学技术研究人乳腺癌细胞株MCF-7细胞受GSM 1800MHz射频电磁场辐照后,其蛋白质表达谱的变化,以探索移动电话信号对细胞正常生理功能的可能影响。方法比吸收率为3．5W／kg时,采用不同时间（1、3、6、12和24h）和辐照模式（间断辐射和连续辐射）的GSM 1800MHz射频电磁场处理MCF-7细胞后,直接抽提蛋白质,然后进行双向凝胶电泳。凝胶经银染后,使用PDQuest软件分析假辐照组与电磁场辐照组间的差异表达蛋白质斑点。每个实验重复3次。结果凝胶上平均可检测到1100个蛋白斑点。3．5W／kg连续辐射6h未发现差异点,其他暴露情况下均可检测到不同数量的差异蛋白,以3．5W／kg间断辐射3h和连续辐照12h检测的差异蛋白点较多,分别为18个和7个。通过搜索SWISS-PROT蛋白数据库,对差异蛋白的类别和功能进行了初步推测,结果表明差异蛋白主要与生物分子的合成和调控、信号转导、DNA损伤修复等功能相关。结论GSM 1800MHz射频电磁场对MCF-7细胞蛋白质表达谱具有一定程度的影响,且依赖于暴露的强度、时间和模式,影响环节可能涉及多个生物学过程。     

Estimation of Estrogenic and Antiestrogenic Activities of Selected Pesticides by MCF-7 Cell Proliferation Assay

Estrogenic activities of 20 selected pesticides—which are used for agricultural production as insecticides, fungicides and herbicides—were examined by estrogen receptor (ER)-dependent MCF-7 cell proliferation assay. Among them, chlordecone, dicofol, methoxychlor, -HCH, fenarimol, EPN, triadimefon, and triadimenol had estrogenic activities, all of which were suppressed by the addition of pure antiestrogen ICI 182,780. The first 5 compounds exhibited binding capacities to ER. The antiestrogenic activity of a compound was examined by estimating its suppressive effect on cell proliferation induced by 30 pM 17-estradiol. Strongly suspected antiestrogens were captan and myclobutanil, both of which were found to have the capacity to bind to ER and which might exert their activities by competing at the level of ER. Antiestrogenic activities of nitrofen, fenitrothion, fenarimol and triadimefon were also suggested. Affinities of the compounds for ER and/or androgen receptor (AR) were lower than those of synthetic estrogen (diethylstilbestrol) and testosterone (mibolerone), respectively. Fenitrothion had the highest affinity to AR. Chlordecone, dicofol, methoxychlor, nitrofen, fenarimol, myclobutanil and pyridate had capacities to bind both ER and AR. Chlordecone and pyridate were much more effective as competitors of estrogen binding to ER than androgen binding to AR and, conversely, nitrofen was a more effective competitor of androgen binding to AR.     

用MCF-7细胞检测有机磷农药拟雌激素样活性

目的 观察常用有机磷农药对MCF-7细胞增殖以及对雌激素受体基因和pS2基因表达的影响。方法 选用乐果、乙酰甲胺磷、久效磷、马拉硫磷、对硫磷、对氧磷6种有机磷农药进行MCF-7人乳腺癌细胞增殖实验和转录活化实验。结果 6种有机磷农药不能诱导MCF-7人乳腺癌细胞增殖,但乐果却能使pS2基因表达上调。结论 乐果可能具有拟雌激素样活性,且引起pS2基因表达上调不通过雌激素受体介导。     

siRNA沉默Fas死亡结构域相关蛋白基因对乳腺癌MCF-7细胞增殖和迁移行为的影响研究

目的探讨siRNA沉默Fas死亡结构域相关蛋白(DAXX)基因对乳腺癌MCF-7细胞增殖和迁移行为的影响,为临床诊断提供参考依据。方法培养MCF-7细胞,观察组对细胞进行siRNA-DAXX转染,空白组不对细胞进行任何处理,对照组对细胞进行siRNA-NC转染,(1)使用RT-PCR和Western Blot法分别检测三组DAXX mRNA和蛋白表达水平,(2)使用MTT法检测三组细胞增殖能力,(3)使用Transwell小室实验检测三组细胞迁移能力。结果 (1)观察组DAXX表达水平与空白组及对照组对比差异有统计学意义(P<0. 05),siRNA能够显著抑制DAXX基因表达和蛋白合成,(2)Western blot显示DAXX基因被沉默后,观察组细胞增殖率仅为空白组或对照组的62. 93%,(3)RT-PCR显示DAXX基因被沉默后,观察组细胞增殖率仅为空白组或对照组的77. 24%;(4)Transwell小室实验结果显示,与空白组及对照组相比,观察组细胞穿过小室的几率显著降低,差异有统计学意义(P<0. 05)。结论 siRNA沉默DAXX基因表达后,乳腺癌MCF-7细胞的增殖能力和迁移能力显著减低,DAXX是一种肿瘤促进基因。     

Retinoic acid induces Gpx2 gene expression in MCF-7 human breast cancer cells.

We showed previously that the selenium-dependent glutathione peroxidase, GPX-GI, encoded by the Gpx2 gene, is highly expressed in the epithelium of the gastrointestinal (GI) tract and sporadically in breast tissue. To investigate whether Gpx2 gene expression is epithelium specific, we used in situ hybridization to show that Gpx2 mRNA is highly expressed in the crypt epithelium of human intestine. We also used Northern analysis to study human breast cells and found Gpx2 mRNA in human mammary epithelial cell lines as well as freshly isolated normal breast epithelial cells. Because we identified three putative retinoic acid response elements (RARE) in the Gpx2 gene, we examined the regulation of the Gpx2 gene expression by all-trans retinoic acid (RA) in RA-sensitive MCF-7 cells and RA-resistant HT29 cells. Without RA, MCF-7 cells had very low levels of Gpx2 mRNA and a low level of glutathione peroxidase (GPX) activity (17 mU/mg protein), whereas HT29 cells had a high level of Gpx2 mRNA and GPX activity (200 mU/mg protein). RA treatment increased Gpx2 mRNA level 3- to 11-fold and resulted in a fourfold increase of GPX activity (80 mU/mg protein) in MCF-7 cells. Neither Gpx2 mRNA level nor GPX activity was increased in HT29 cells. These results show that the Gpx2 gene is expressed in both breast and intestinal epithelium cells, and suggest that its expression can be highly regulated by retinoic acid, a known differentiation agent.     

Eicosapentaenoic acid suppresses cell proliferation in MCF-7 human breast cancer xenografts in nude rats via a pertussis toxin-sensitive signal transduction pathway

The type and content of dietary PUFAs have profound influences on the growth rate of transplantable human breast cancers in immunodeficient rodents. Diets enriched in linoleic acid (LA), an (n-6) fatty acid, stimulate tumor growth, whereas dietary fats containing (n-3) fatty acids slow such growth. Interactions between LA and (n-3) fatty acids capable of regulating cell proliferation in solid tumors in vivo are not yet well defined. Here we tested the hypothesis that plasma eicosapentaenoic acid (EPA), an (n-3) fatty acid, suppresses cell proliferation in MCF-7 human breast cancer xenografts via a pertussis toxin-sensitive reduction of intratumor cAMP, LA uptake, and formation of the mitogen 13-hydroxyoctadecadienoic acid (13-HODE) from LA. Plasma fatty acid uptake and 13-HODE release were determined in control and EPA-treated xenografts from arteriovenous differences measured during perfusion in situ. Intratumor cAMP, extracellular signal-regulated kinase p44/p42 (ERK1/2) phosphorylation, and [3H]thymidine incorporation (TTI) were measured in tumors freeze-clamped at the end of the perfusions. Arterial blood containing EPA caused significant decreases (P < 0.05) in cAMP, uptake of SFA, monounsaturated fatty acids, and (n-6) PUFA, 13-HODE formation, ERK1/2 phosphorylation, and TTI in MCF-7 xenografts. These effects of EPA were reversed by the addition of either pertussis toxin or 8-bromoadenosine-cAMP to the EPA-containing arterial blood. Addition of 13-HODE to the EPA-containing arterial blood restored phosphorylated ERK1/2 and TTI but not FA uptake. The results suggest that EPA regulates cell proliferation in MCF-7 xenografts via a novel inhibitory G protein-coupled, (n-3) FFA receptor-mediated signal transduction pathway.     

RNA干扰hTERT基因对人乳腺癌细胞株MCF-7周期及凋亡影响的研究

目的 观察载体介导的RNA干扰技术能否有效抑制人乳腺癌细胞株MCF-7的hTERT的表达及其对细胞周期及凋亡的影响.方法 构建2个针对hTERT基因表达短发夹状siRNA的真核表达载体（pshRNA-hTERT）并转染人乳腺癌细胞株MCF-7,通过RT-PCR检测该基因mRNA,Western blot蛋白质检测,端粒酶活性检测,流式细胞仪检测细胞周期及凋亡等方法检测RNAi效果,从中筛选出基因沉默效果好的靶位点.结果 转染乳腺癌细胞后,pshRNA - hTERT1,2质粒均能抑制hTERT基因表达,mRNA表达分别下调了54.6%,55.2% 蛋白表达分别下调46.6%,47.8%.端粒酶活性均明显下降.对乳腺癌细胞周期中S期细胞明显减少,G1/G0期细胞显著增加.结论 RNAi在体外明显抑制乳腺癌细胞中hTERT基因的表达和瘤细胞增殖.