靶向下调FOXM1基因表达对乳腺癌MDA-MB-231细胞增殖的影响

目的：探讨靶向抑制FOXM1对乳腺癌细胞增殖能力的影响,为乳腺癌的个性化靶向治疗提供理论依据。方法：利用重组真核转录载体pSilencer1．0-U6-FOXMI—shRNA,脂质体法转染乳腺癌细胞株MDA-MB-231,下调其FOXM1基因表达。采用四甲基偶氮唑盐（MTT）比色法、平板克隆形成实验观察细胞增值曲线以及克隆形成能力;采用实时定量·聚合酶链反应（Real—timeqPCR）、蛋白免疫印迹法（Westemblot）分别检测FOXMl基因在mRNA、蛋白水平的表达变化。结果：重组载体pSileneerl．0-U6-FOXMl-shRNA转染MDA-MB-231细胞后,与对照组相比,增殖速率明显下降（P〈0．05）,平板克隆形成显著减少（P〈0．05）,重组载体转染后显著抑制MDA—MB-231细胞中FOXM1基因在mRNA、蛋白水平的表达。结论：沉默FOXMI基因对乳腺癌细胞株MDA—MB-231生长具有抑制作用,为阐明乳腺癌发病机制提供了新的切入点,也为临床抑制肿瘤生长提供了新的作用靶点。     

BSP基因RNA干扰对乳腺癌MDA-MB-231BO细胞生物学特性的影响

旨在研究RNA干扰(RNA interference,RNAi)抑制骨唾液酸蛋白(bone sialoprotein,BSP)基因表达后对人乳腺癌细胞MDA-MB-231BO生物学特性的影响。应用pSilencer5.1-U6Retro构建针对BSP基因的siRNA逆转录病毒重组表达质粒,将重组质粒转染293细胞制备病毒悬液感染MDA-MB-231BO细胞,利用嘌呤霉素筛选抑制BSP表达的乳腺癌细胞。Western blotting检测细胞内BSP蛋白表达,采用MTT法和集落形成试验检测细胞的增殖,流式细胞仪检测细胞周期变化。结果显示,成功构建BSP基因RNAi稳定转染的231BO-BSP27细胞。231BO-BSP27细胞内BSP蛋白表达抑制率为69.3%,与对照组细胞相比,231BO-BSP27细胞的生长速率和克隆形成率明显降低;S期细胞数量明显减少,G0/G1期细胞增多。由此证实,逆转录病毒介导的RNAi能实现BSP基因稳定沉默,从而抑制MDA-MB-231BO细胞的生长和增殖。     

RNA干扰对MDA-MB-231细胞中CaSR基因表达的影响

目的:运用RNA干扰技术,观察siRNA表达载体在乳腺癌细胞MDA-MB-231中对CaSR基因表达的影响。方法:构建靶向CaSR基因的RNA干扰表达载体,用脂质体转染乳腺癌细胞株MDA-MB-231,运用Real-Time荧光定量PCR,Westernblot技术分别从mRNA以及蛋白表达水平检测CaSR基因表达的变化。结果:所构建的质粒载体成功的在MDA-MB-231细胞中抑制了CaSR mRNA及其蛋白的表达。与对照组相比,psiRNA-CaSR载体对CaSR mRNA的抑制率达到65%,对CaSR蛋白抑制率约为70%。结论:实验证明所设计的shRNA片段可以有效地抑制CaSR基因的表达,为下一步研究工作奠定了基础。     

PPARγ基因真核表达载体的构建及其在乳腺癌MDA—MB-231细胞中的表达

目的：构建以绿色荧光蛋白（GFP）为报告基因的重组表达质粒pEGFP—C1—PPARγ,观察小鼠PPARγ基因在MDA-MB-231细胞中的表达及定位。方法：采用克隆和亚克隆技术构建小鼠PPARγ基因真核表达载体,脂质体Lip2000介导转染MDA—MB-231细胞,real—time PCR和western—blot验证其mRNA和蛋白的表达,荧光显微镜观察该基因亚细胞定位。结果：酶切和测序结果证实重组质粒含有PPAIh编码区序列且插入方向正确,转染后观察该基因亚细胞定位于胞核,胞质有弥散分布。结论：成功构建了小鼠PPARγ基因真核表达载体,该基因在MDA—MB-231细胞中成功表达,PPARγ基因主要集中表达于胞核。     

沉默FBI-1基因对三阴性乳腺癌细胞MDA-MB-231增殖和凋亡的影响

本研究旨在观察短发夹状RNA (short hairpin RNA, shRNA)介导的人类免疫缺陷病毒短转录诱导物连接因子1 (FBI-1)基因沉默对三阴性乳腺癌细胞MDA-MB-231增殖和凋亡的影响。用qRT-PCR和Western blot分别检测FBI-1、Bcl-2、Bax、cleaved-Caspase3和Survivin的mRNA和/或蛋白的表达水平;采用shRNA干扰技术沉默MDA-MB-231细胞中FBI-1基因的表达;用CCK-8法以及克隆形成实验检测细胞增殖;用流式细胞术检测细胞凋亡;用裸鼠皮下成瘤实验检测细胞的成瘤能力。结果显示,MDA-MB-231细胞的FBI-1 mRNA和蛋白的表达水平明显高于正常乳腺上皮细胞MCF-10A;经shRNA靶向沉默FBI-1基因表达后,细胞增殖能力明显降低,细胞凋亡率显著增高,伴随Bcl-2和Survivin蛋白表达明显下调、Bax蛋白表达显著上调和Caspase 3活化,MDA-MB-231细胞的裸鼠皮下成瘤能力受抑制。以上结果提示,靶向沉默FBI-1基因表达可以抑制MDA-MB-231细胞增殖,诱导细胞凋亡并抑制细胞的裸鼠皮下成瘤能力。     

转化生长因子β1影响三阴性乳腺癌顺铂耐药的机制研究

摘要 目的：建立三阴性乳腺癌MDA-MB-231/顺铂（DDP）耐药细胞株,探讨转化生长因子β1（TGF-β1）调控三阴性乳腺癌DDP耐药的机制。方法：采用小剂量间歇诱导法建立MDA-MB-231耐药细胞株（MDA-MB-231/DDP）,在MDA-MB-231/DDP中构建TGF-β1沉默细胞并分为TGF-β1沉默组（sh-TGF-β1）、阴性对照组以及对照组,实时定量聚合酶链反应（RT-qPCR）检测TGF-β1含量。另取MDA-MB-231细胞和MDA-MB-231/DDP细胞分为MDA-MB-231组（正常培养MDA-MB-231敏感细胞）、MDA-MB-231-DDP组（正常培养MDA-MB-231 DDP耐药细胞）、TGFβ1-shRNA组（MDA-MB-231 DDP细胞转染TGFβ1-shRNA慢病毒载体）和MDA-MB-231-DDP+3-MA组（MDA-MB-231 DDP细胞给予5mM 3-MA处理2 h）。细胞计数试剂盒（CCK-8）法检测耐药株的半数抑制浓度（IC₅₀）,并计算耐药指数及逆转耐药指数,RT-qPCR检测TGF-β1含量,蛋白印迹法（Western blot）检测TGF-β1、自噬相关蛋白LC3-I、LC3-II表达量,激光共聚焦显微镜观察自噬流的变化,应用SPSS 20.0软件进行统计分析。结果：成功建立DDP耐药细胞株MDA-MB-231/DDP,耐药指数为5.231;MDA-MB-231/DDP细胞的TGF-β1 mRNA表达和蛋白表达较MDA-MB-231细胞显著上调（P<0.05）。DDP耐药细胞MDA-MB-231/DDP中自噬相关蛋白LC3-II/LC3-I表达较MDA-MB-231细胞显著升高（P<0.05);应用自噬抑制剂3-甲基腺嘌呤（3-MA）后MDA-MB-231/DDP细胞自噬相关蛋白LC3-II/LC3-I表达显著下降（P<0.05);沉默MDA-MB-231/DDP细胞的TGF-β1基因后,DDP耐药细胞株的耐药指数从5.231下降到3.404,同时自噬相关蛋白LC3-II/LC3-I表达降低（P<0.05）,且激光共聚焦显微镜观察到黄色和红色斑点的显著减少,表明自噬受到抑制。结论：TGF-β1与三阴性乳腺癌DDP耐药有关,其机制可能是增加自噬引起MDA-MB-231细胞DDP耐药。通过沉默TGF-β1可降低自噬水平,恢复三阴性乳腺癌细胞对DDP的敏感性。     

逆转录病毒载体介导的RNAi抑制乳腺癌细胞BSP基因表达

目的构建抑制人日5P基因表达的RNA干扰逆转录病毒载体,筛选建立稳定抑制BSP表达的MDA-MB-231BO细胞系。方法构建靶向人BSP基因的逆转录病毒重组质粒pSilencer—BSP27、pSilencer—BSP81和pSilencer—BSP100。将其包装成病毒后感染MDA—MB-23180细胞。用RT—PCR和Western印迹检测成功感染细胞（231BO．BSP27、231BO．BSP81、231BO—BSP100细胞）BSP基因的抑制效果。结果双酶切和测序结果显示重组核酸片段序列与设计的序列完全相同。RT—PCR和Western印迹结果显示231BO—BSP27、BO—BSP81和231BO—BSP100细胞BSP基因在mRNA水平和蛋白水平抑制效率分别为：70．8％、79．4％和30．1％：69．3％,75．2％和27．8％。结论成功构建抑制人BSP基因表达的RNAi逆转录病毒载体pSilencer．BSP27、pSilencer．BSP81和pSilencer—BSP100。获得高效稳定抑制BSP表达的231BO—BSP27、231BO．BSP81细胞系。     

Akt3稳定表达细胞株的建立及其对MDA-MB-231细胞增殖的影响

目的 构建人蛋白激酶Bγ（Akt3）基因编码区序列（cDNA）的真核表达载体、建立其稳定表达细胞株并观察其对MDA-MB-231细胞增殖的影响.方法 从流产胎儿脑组织中提取总RNA,采用RT-PCR方法扩增Akt3 cDNA的全长序列后克隆入pEGFP-N2质粒中,构建成Akt3基因真核表达载体,然后转染入MDA-MB-231细胞中,新霉素筛选稳定转染细胞克隆,通过MTT实验,研究转染Akt3基因前后细胞增殖的变化.结果 重组载体经酶切鉴定和测序证实目的 基因正确无误.Western印迹检测结果显示AKT3融合蛋白在MDA-MB-231细胞中表达良好,而转染空载体及未转染细胞对照中未见有此融合蛋白质条带;MTT结果显示AKT3表达上调的稳定克隆组,其增殖活性显著高于空载体稳定转染细胞组及未转染亲代细胞组,差异具有统计学意义（P＜0.01）,而后两者差异无统计学意义（P＞0.05）.结论 Akt3过表达可增强MDA-MB-231细胞的增殖.     

PPARγ基因真核表达载体的构建及其在乳腺癌MDA-MB-231细胞中的表达

目的:构建以绿色荧光蛋白(GFP)为报告基因的重组表达质粒pEGFP-C1-PPARγ,观察小鼠PPARγ基因在MDA-MB-231细胞中的表达及定位.方法:采用克隆和亚克隆技术构建小鼠PPARγ基因真核表达栽体,脂质体Lip2000介导转染MDA-MB-231细胞,real-time PCR和western-blot验证其mRNA和蛋白的表达,荧光显微镜观察该基因亚细胞定位.结果:酶切和测序结果证实重组质粒含有PPARγ编码区序列且插入方向正确,转染后观察该基因亚细胞定位于胞核,胞质有弥散分布.结论:成功构建了小鼠PPARγ基因真核表达载体,该基因在MDA-MB-231细胞中成功表达,PPARγ基因主要集中表达于胞核.     

转录因子FOXM1在卵巢癌细胞中的表达及其对侵袭转移能力的影响

目的:研究上皮性卵巢癌细胞中FOXM1的表达,探讨FOXM1与MMP9之间的相关性以及与卵巢癌细胞侵袭、转移的关系。方法:采用Real-time RT-PCR、Western blotting技术检测pcDNA3.1-FOXM1和FOXM1-siRNA分别转染卵巢癌细胞株HO-8910(低转移)和HO-8910PM(高转移)前后FOXM1的表达水平,用Transwell方法检测转染该序列后HO-8910和HO-8910PM细胞侵袭能力的改变,并用荧光素酶双报告基因分析技术检测FOXM1对MMP9的调控作用。结果:与对照组和空载组相比,转染了pcDNA3.1-FOXM1的HO-8910细胞FOXM1 mRNA、蛋白表达显著升高,而转染了FOXM1-siRNA的高转移细胞株HO-8910PM FOXM1 mRNA、蛋白表达显著降低(P0.05);相对于空载体组和空白组,pcDNA3.1-FOXM1转染组细胞的侵袭能力明显增强,而FOXM1-siRNA转染细胞的侵袭能力明显降低(P0.05);FOXM1参与对MMP9的转录调控作用(P0.05)。结论:FOXM1可能是一个潜在的治疗靶点,通过下调FOXM1的表达,从而抑制卵巢癌的浸袭和转移。     

Possible role of Pax-6 in promoting breast cancer cell proliferation and tumorigenesis

Pax 6, a member of the paired box (Pax) family, has been implicated in oncogenesis. However, its therapeutic potential has been never examined in breast cancer. To explore the role of Pax6 in breast cancer development, a lentivirus based short hairpin RNA (shRNA) delivery system was used to knockdown Pax6 expression in estrogen receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) breast cancer cells. Effect of Pax6 silencing on breast cancer cell proliferation and tumorigenesis was analyzed. Pax6-RNAi-lentivirus infection remarkably downregulated the expression levels of Pax6 mRNA and protein in MCF-7 and MDA-MB-231 cells. Accordingly, the cell viability, DNA synthesis, and colony formation were strongly suppressed, and the tumorigenesis in xenograft nude mice was significantly inhibited. Moreover, tumor cells were arrested at G0/G1 phase after Pax6 was knocked down. Pax6 facilitates important regulatory roles in breast cancer cell proliferation and tumor progression, and could serve as a diagnostic marker for clinical investigation.     

Role of ornithine decarboxylase in breast cancer

Ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis that decarboxylates ornithine to putrescine, has become a promising target for cancer research. The aim of this study is to investigate the role of ODC in breast cancer. We detected expression of ODC in breast cancer tissues and four breast cancer cell lines, and transfected breast cancer cells with an adenoviral vector carrying antisense ODC (rAd-ODC/Ex3as) and examined their growth and migration. ODC was overexpressed in breast cancer tissues and cell lines compared with non-tumor tissues and normal breast epithelial cells, and there was a positive correlation between the level of ODC mRNA and the staging of tumors. The expression of ODC correlated with cyclin D1, a cell cycle protein, in synchronized breast cancer MDA-MB-231 cells. Gene transfection of rAd-ODC/Ex3as markedly down-regulated expression of ODC and cyclin D1, resulting in suppression of proliferation and cell cycle arrest at G₀–G₁ phase, and the inhibition of colony formation, an anchorage-independent growth pattern, and the migratory ability of MDA-MB-231 cells. rAd-ODC/Ex3as also markedly reduced the concentration of putrescine, but not spermidine or spermine, in MDA-MB-231 cells. The results suggested that the ODC gene might act as a prognostic factor for breast cancer and it could be a promising therapeutic target.     

RNA干扰抑制癌胚抗原表达对结肠癌细胞增殖的影响

癌胚抗原（CEA）作为肿瘤标志物,在多种恶性肿瘤中高表达.为探索CEA在肿瘤发生发展过程中的生物学作用,本研究以结肠癌细胞株8307为研究对象,应用RNAi技术抑制CEA在8307细胞中的表达,观察其对8307细胞生长的影响.依据siRNA设计原则,设计合成靶向CEA的shRNA并克隆到pSilencer2.1-U6 neo载体中,成功构建了CEA shRNA表达载体,通过脂质体介导转染8307细胞,经G418筛选出抑制CEA表达的稳定细胞.RT-PCR、Western印迹分别检测CEA mRNA及蛋白表达水平,MTT及集落形成实验检测细胞增殖活性.实验结果显示,构建的CEA shRNA表达载体明显抑制CEA mRNA及蛋白水平的表达.MTT实验中,CEA表达下调的8307细胞生长活性降低,与对照组相比,抑制率达39%（P<0.05）,细胞集落形成能力也显著降低（P<0.05）.上述结果初步证明,构建的CEA shRNA表达载体能明显降低CEA的表达,并抑制结肠癌细胞增殖活性.     

EBP50 exerts tumor suppressor activity by promoting cell apoptosis and retarding extracellular signal-regulated kinase activity

The expression of Ezrin-radixin-moesin-binding phosphoprotein-50 (EBP50) and the intragenic mutation of the ebp50 gene have been reported to correlate with human breast cancer development, but the exact impacts on breast cancer development and its molecular mechanism are not fully understood. In this study, we investigate the potential function of EBP50 through over-expression in the breast cancer cell line, MDA-MB-231, which has low EBP50 protein expression levels. The effects of EBP50 over-expression on cellular proliferation, anchorage-independent growth and apoptosis were examined. In addition, the activity of extracellular signal-regulated kinase (ERK) was also determined. Our results show that a decrease of cellular proliferation and attenuation of colony-forming ability were evident in MDA-MB-231 cells stably transfected with an EBP50 expressing plasmid (EBP-231) when compared with control cells. There was also a statistically significant increase in spontaneous apoptosis in EBP-231 cells accompanied by an attenuation in ERK activity. Altogether, our results suggest that restoring EBP50 expression could suppress breast cancer cell proliferation by promoting cell apoptosis and inhibiting ERK activity, and that EBP50 may be a target for development of diagnostics and therapeutics in breast cancer.     

鞘氨醇激酶1参与依托泊苷抑制人乳腺癌MDA-MB-231细胞增殖、迁移的研究

目的利用抑制乳腺癌MDA-MB-231细胞中SK-1基因表达,结合依托泊苷对细胞增殖的影响,研究乳腺癌的治疗新方法。方法将依托泊苷分别处理野生型及SK-1敲除型MDA-MB-231细胞,^3H-TdR掺入法分析细胞增殖,Transwell法分析细胞迁移,Western印迹检测SK-1蛋白表达及细胞周期检验点相关信号因子的蛋白表达,RT-PCR检测细胞内SK-1的mRNA表达量。结果依托泊苷在较高剂量时,MDA-MB-231细胞存活率明显下降,但依托泊苷却呈浓度依赖性促进乳腺癌细胞SK-1 mRNA及蛋白水平表达,将SK-1敲除,细胞迁移率下降,而且可以增强G1期各抑癌基因的激活或高表达,使细胞周期阻滞。结论SK-1基因敲除有效增强肿瘤细胞对化疗药物的敏感性。     

BMP9 inhibits the bone metastasis of breast cancer cells by downregulating CCN2 (connective tissue growth factor,CTGF) expression

Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor-β superfamily, regulate a wide range of cellular responses including cell proliferation, differentiation, adhesion, migration, and apoptosis. BMP9, the latest BMP to be discovered, is reportedly expressed in a variety of human carcinoma cell lines, but the role of BMP9 in breast cancer has not been fully clarified. In a previous study, BMP9 was found to inhibit the growth, migration, and invasiveness of MDA-MB-231 breast cancer cells. In the current study, the effect of BMP9 on the bone metastasis of breast cancer cells was investigated. After absent or low expression of BMP9 was detected in the MDA-MB-231 breast cancer cells and breast non-tumor adjacent tissues using Western blot and immunohistochemistry, In our previous study, BMP9 could inhibit the proliferation and invasiveness of breast cancer cells MDA-MB-231 in vitro and in vivo. This paper shows that BMP9 inhibit the bone metastasis of breast cancer cells by activating the BMP/Smad signaling pathway and downregulating connective tissue growth factor (CTGF); however, when CTGF expression was maintained, the inhibitory effect of BMP9 on the MDA-MB-231 cells was abolished. Together, these observations indicate that BMP9 is an important mediator of breast cancer bone metastasis and a potential therapeutic target for treating this deadly disease.