miRNA-34a抑制乳腺癌细胞MCF-7、MDA-MB-231的增殖与侵袭

目的:研究miRNA-34a(miR-34a)对乳腺癌细胞MCF-7、MDA-MB-231的生物调控作用。方法:采用定量PCR检测人乳腺上皮细胞MCF-10A,乳腺癌细胞株MCF-7、T47D、MDA-MB-231、MDA-MB-453、Hs578T中miR-34a的表达水平。通过miR-34a mimics分别上调MCF-7、MDA-MB-231细胞中miR-34a的表达水平,MTT和Transwell检测肿瘤细胞增殖能力、侵袭力等生物学行为的变化。结果:乳腺癌细胞MCF-7、T47D、MDA-MB-231、MDA-MB-453、Hs578T中miR-34a处于低表达水平。通过miR-34a mimics上调MCF-7、MDA-MB-231细胞中miR-34a的表达后,细胞的增殖能力被miR-34a抑制（P＜0.05）,miR-34a对细胞侵袭有显著抑制作用（P＜0.05）。结论:miR－34a在乳腺癌细胞MCF-7、T47D、MDA-MB-231、MDA-MB-453及Hs578T中低表达,miR-34a抑制乳腺癌细胞MCF-7、MDA-MB-231的细胞增殖和侵袭能力。     

乳腺癌MCF-7细胞通过TGF-β诱导的上皮-间质转化获得耐药北大核心CSCD

目的:通过研究高侵袭转移性乳腺癌细胞株MDA-MB-231和低侵袭转移性细胞株MCF-7中上皮-间质转化(epithelial-mesenchymal transition,EMT)和耐药的相关性,以探讨乳腺癌耐药的机制。方法:采用实时荧光定量PCR法检测MDA-MB-231和MCF-7细胞中EMT标志物E-钙黏蛋白(E-cadherin)、波形蛋白(vimentin)和纤黏蛋白(bronectin)以及转录因子Snail、Slug和锌指E-box同源结合框1(Zincnger E-box binding homeobox 1,ZEB1)mRNA的表达水平;划痕愈合实验和Transwell小室实验分别检测MDA-MB-231和MCF-7细胞的迁移和侵袭能力;CCK-8法检测MDA-MB-231和MCF-7细胞对化疗药物5-氟尿嘧啶、顺铂和紫杉醇的敏感性,并采用实时荧光定量PCR法检测耐药基因多重耐药相关蛋白1(multidrug resistance-associated protein 1,MDR1)和MDR相关蛋白1(MDR-associated protein,MRP1)mRNA的表达水平。用转化生长因子β(transforming growth factor-β,TGF-β)诱导MCF-7细胞发生EMT,或用靶向E-cadherin基因的E-cadherin-siRNA沉默EMT相关标志物E-cadherin的表达,再用CCK-8法检测MCF-7细胞对5-氟尿嘧啶敏感性的变化。结果:MDA-MB-231细胞中vimentin、fibronectin、Slug和ZEB1 mRNA的表达水平均高于MCF-7细胞(P值均<0.000 1),E-cadherin mRNA的表达水平明显低于MCF-7细胞(P=0.000 2),Snail mRNA的表达水平无明显差异。与MCF-7细胞相比,MDA-MB-231细胞的迁移和侵袭能力明显更强(P值均<0.000 1);5-氟尿嘧啶、顺铂和紫杉醇对MDAMB-231细胞的半数抑制浓度(half maximal inhibitory concentration,IC50)值明显高于MCF-7细胞(P值均<0.05);MDA-MB-231细胞中耐药相关基因MDR1和MRP1 mRNA表达水平明显更高(P值均<0.000 1)。TGF-β诱导MCF-7细胞发生EMT后,5-氟尿嘧啶对MCF-7细胞的IC50值明显上升(P<0.05);沉默E-cadherin表达后,MCF-7细胞对5-氟尿嘧啶的耐药性明显增强(P<0.05)。结论:乳腺癌中EMT和耐药存在相关性,诱导EMT发生可导致细胞耐药。     

三氧化二砷对乳腺癌细胞MDA-MB-231雌激素受体α的去甲基化作用

目的研究三氧化二砷（As2O3）作用于乳腺癌细胞MDA-MB-231后,对雌激素受体α（ERα）表达的影响,并初步探讨其机制。方法用As2O3处理ERα阴性的人乳腺癌细胞MDA-MB-231,甲基化特异性PCR（MSP）检测ERα启动子CpG岛的甲基化状态,反转录PCR（RT-PCR）检测ERα mRNA表达水平的变化。以雌激素受体α阳性的人乳腺癌细胞MCF-7 为阳性对照。结果MDA-MB-231细胞ERα启动子CpG岛存在高甲基化,经过As2O3处理后,CpG岛高甲基化水平降低,ERα mRNA恢复表达。结论 一定浓度的As2O3能够使人乳腺癌细胞MDA-MB-231 ERα启动子中的CpG岛发生去甲基化,重新恢复mRNA的表达。     

人乳腺癌细胞雌激素受体基因的去甲基化及其表达

目的探讨人乳腺癌雌激素受体（ER）基因启动子的去甲基化和ER蛋白表达功能恢复的关系。方法用甲基化特异性PCR（MSP）和亚硫酸氢盐基因组测序方法检测乳腺癌细胞ER基因启动子的甲基化状态;用RT-PCR方法从mRNA水平检测ER和孕激素受体（PR）基因的表达;用Western blot方法从蛋白水平探测ER基因的表达;MTT方法检测重新表达ER蛋白的功能。结果在ER阴性乳腺癌细胞系MDA-MB-231中,ER基因启动子甲基化的水平较高,而ERmRNA和ER蛋白均不表达。MDA-MB-231细胞用去甲基化剂5-杂氮-2’-脱氧胞嘧啶（5-AZA-2＇-deoxyC）处理,可以恢复该细胞系ERmRNA和ER蛋白的表达,同时伴有ER基因启动子甲基化水平的降低以及PR基因的表达。MDA-MB-231细胞经去甲基化逆转ER表达后,应用三苯氧胺治疗,乳腺癌细胞增殖受到明显抑制（P〈0．05）。结论人乳腺癌ER基因的失活与其基因启动子高甲基化关系密切。去甲基化剂5-AZA-2＇-deoxyC能较好地降低MDA-MB-231细胞DNA甲基化,并有效激活功能性ER基因的再表达,为ER基因阴性的乳腺癌患者接受内分泌治疗提供了新的途径和理论基础。     

高与低表达RSK4基因人乳腺癌细胞株的筛选及鉴定

目的:探讨核糖体S6激酶4(RSK4)抑癌基因在人乳腺癌细胞株MDA-MB-231、T47D、Bcap37和MCF-7中的表达,并筛选出高和低表达RSK4基因的乳腺癌细胞。方法:逆转录聚合酶链反应(RT-PCR)和蛋白质印迹法从mRNA和蛋白水平检测RSK4在MDA-MB-231、T47D、Bcap-37和MCF-7 4种乳腺癌细胞株中的表达。结果:人乳腺癌细胞株MDA-MB-231、T47D、Bcap37和MCF-7中均有RSK4基因表达,其中,MCF-7细胞RSK4表达水平最高,为表达量最低的MDA-MB-231细胞的2.9倍,MCF-7细胞RSK4蛋白表达水平也最高,与其他3种细胞株相比,差异有统计学意义,P<0.001。RT-PCR法和蛋白质印迹法检测结果一致,具有高度相关性,r=0.766,P<0.001。结论:人乳腺癌细胞株MCF-7为高表达RSK4基因的细胞,MDA-MB-231细胞为低表达RSK4基因的细胞,两者均可作为人乳腺癌细胞中研究RSK4基因的实验材料。     

PPAPDC1A在体内外对乳腺癌细胞增殖、侵袭和转移能力的影响

目的:通过构建稳定过表达和干扰PPAPDC1A的乳腺癌细胞株,探讨PPAPDC1A对乳腺癌细胞增殖、侵袭和转移能力的影响。方法:利用CCK-8和Transwell实验检测PPAPDC1A稳定过表达和干扰后对乳腺癌细胞体外增殖和侵袭能力的影响。采用裸鼠皮下成瘤实验检测PPAPDC1A对乳腺癌细胞体内增殖和裸鼠致瘤性的作用。利用免疫组织化学染色法检测各组肿瘤组织中Ki-67的表达。通过裸鼠尾静脉注射实验检测PPAPDC1A对乳腺癌MCF-7细胞和MDA-MB-231细胞体内转移能力的影响。结果:成功建立稳定过表达PPAPDC1A的乳腺癌MCF-7细胞株和稳定干扰PPAPDC1A的乳腺癌MDA-MB-231细胞株;CCK-8和Transwell实验结果显示,与MCF-7和MCF-7-Vector细胞株相比,MCF-7-PPAPDC1A细胞株的生长速度显著增快,穿膜细胞数量多（P＜0.05）;与此相反,MDA-MB-231-shPPAPDC1A组细胞的生长速度和穿膜细胞数明显少于MDA-MB-231-shNC和MDA-MB-231 细胞株（P＜0.05）。动物实验结果显示,与MCF-7-Vector组相比,MCF-7-PPAPDC1A组的肿瘤生长速度较快,肿瘤的体积较大,Ki-67的阳性率高,肺转移灶的数目增多（P＜0.05）;与此相反,与MDA-MB-231-shNC组相比MDA-MB-231-shPPAPDC1A组的肿瘤生长速度较慢,肿瘤的体积较小,Ki-67的阳性率低,肺转移灶的数目减少（P＜0.05）。结论:PPAPDC1A对乳腺癌细胞的增殖、侵袭和转移有促进作用。     

Med19基因沉默对p53野生型和突变型乳腺癌细胞紫杉醇化疗疗效的影响

目的：探讨下调中介体（mediator,Med）19表达是否增加紫杉醇(pacliatxel, PTX)对p53野生型和突变型乳腺癌细胞化疗的疗效。方法：构建Med19RNA干扰（RNAi）慢病毒,分别感染p53野生型的乳腺癌细胞MCF-7和p53突变型的乳腺癌细胞MDA-MB-231,两种细胞均分为Med19基因敲减组（KD组：细胞感染pGcscil-Med19-siRNA-GFP ）、空载体感染组（NC 组：细胞感染pGcscil-Med19-NC-GFP）、对照组（CON组：未感染慢病毒的乳腺癌细胞）,荧光显微镜观察慢病毒感染效率。Western blotting检测Med19基因沉默后各组细胞内P53、磷酸化P53（pP53）、P21蛋白表达水平的变化。紫杉醇分别作用于Med19基因沉默前后的MCF-7和MDA-MB-231细胞,MTT法检测细胞增殖抑制率的变化,流式细胞术检测细胞周期和凋亡率的变化。结果：KD组和NC组细胞的荧光感染效率均大于90%,表明获得了满意的感染效率。与CON组和NC组相比,两种细胞KD组的Med19蛋白表达水平均下降,差异有统计学意义（均P<0.05）。MCF-7细胞KD组P53、pP53、P21蛋白表达上调,差异有统计意义（均P<0.05）。在0.01～50 μg/ml 范围内,紫杉醇抑制两种乳腺癌细胞的生长增殖并呈浓度依赖性（P<0.05）,对KD组的抑制率和细胞凋亡率均高于NC组及CON组,差异有统计学意义（均P<0.05）;但MDA-MB-231细胞各组间抑制率差异无统计学意义（均P>0.05）。10 μg/ml紫杉醇导致两种细胞的KD组和NC组均出现G2/M期阻滞,并且MCF-7细胞KD组G0/G1期细胞较NC组显著增加（P<0.05）。结论：Med19基因沉默增强紫杉醇对p53野生型乳腺癌MCF-7细胞化疗的疗效,其机制可能为增强了p53基因的表达活化,通过其下游基因p21 调节细胞周期、促进细胞凋亡。     

hCLP46基因在不同侵袭转移潜能乳腺癌细胞表达中的差异及其意义

目的 探讨hCLP46基因在MCF-7和MDA-MB-231乳腺癌细胞中表达的差异性及其意义。方法 采用RT-PCR的方法检测2个细胞系(乳腺癌低度侵袭转移细胞系MCF-7、中度侵袭转移细胞系MDA-MB-231)中hCLP46 mRNA的表达差异。取MCF-7和MDA-MB-231细胞株进行培养,分别加入100 μmol/L的转化生长因子-β(TGF-β)并设对照组,培养72 h,用Western-blot方法分析P15蛋白表达。结果 RT-PCR检测hCLP46结果显示,在MCF-7和MDA-MB-231细胞系中,内参基因GAPDH的表达量相近,hCLP46基因在两个细胞系中均表达,其中MDA-MB-231细胞系中的表达高于MCF-7细胞系。两个细胞系分别加入TGF-β培养72 h后,与相应的对照细胞系相比,P15的表达均有降低,hCLP46基因高表达的MDA-MB-231细胞中P15表达较MCF-7细胞显著降低。结论 hCLP46基因过表达可能抑制TGF-β对MDA-MB-231和MCF-7乳腺癌细胞P15基因的上调,hCLP46可能在乳腺癌的发病中起到一定作用。     

Nimesulide对乳腺癌细胞株化疗敏感性的影响及机制研究

目的：探讨选择性环氧化酶2（cy-clooxygenase-2,COX-2）抑制剂nimesulide对乳腺癌细胞株化疗敏感性的影响,同时探讨其可能机制。方法：利用体外培养的乳腺癌细胞株MDA-MB-231、MCF-7,MTT法比较多柔比星（ADM）及联合不同浓度的nimesulide对两种细胞抑制率的影响（IC50）;应用逆转录聚合酶链反应（RT-PCR）观察不同浓度nimesulide对两种细胞多药耐药蛋白（MDR1）mRNA的影响。结果：Nimesulide能增加ADM对MDA-MB-231、MCF-7的细胞毒作用,这种作用与nimesulide呈剂量依赖性,对COX-2高表达的MDA-MB-231细胞更加敏感;nimesulide能降低MDR1 mRNA的表达水平,并呈剂量依赖性（10、25、50μmol／L nimesulide）。结论：选择性COX-2抑制剂nimesulide能增加ADM对MDA-MB-231、MCF-7的细胞毒作用,这种作用可能与MDR1水平的下调有关,为选择性COX-2抑制剂联合细胞毒药物用于乳腺癌的化疗提供了实验依据。     

微RNA-223与微RNA-29c在乳腺癌中的表达及意义

目的研究微RNA(miRNA)-223与miRNA-29c在乳腺癌组织、癌旁组织(距离肿瘤边缘2 cm的非癌组织)以及乳腺癌细胞株中的表达情况,探讨miRNA-223、miRNA-29c的表达水平与乳腺癌患者临床病理特征之间的相关性。方法采用回顾性横断面研究方法,收集2013年7月至2014年1月经重庆市肿瘤研究所初次确诊为乳腺癌的新鲜穿刺的癌组织标本125例(有81例具有完整的临床病理资料),其中12例同时取了癌旁组织,并选择不同分子亚型的乳腺癌细胞株MCF-7(ER阳性)、MDA-MB-231(三阴性)和SKBR3(HER-2阳性),利用实时荧光定量PCR检测乳腺癌组织和癌旁组织及各乳腺癌细胞株中miRNA-223与miRNA-29c的表达水平。采用配对样本t检验分析12例乳腺癌组织和癌旁组织中miRNA-223与miRNA-29c表达水平的差异,采用Pearson相关分析乳腺癌组织中miRNA-223和miRNA-29c表达水平的相关性,并采用独立样本t检验分析其中81例临床病理资料完整者乳腺癌组织中miRNA-223与miRNA-29c表达水平与临床病理特征之间的关系,采用单因素方差分析比较3种乳腺癌细胞株之间miRNA-223和miRNA-29c表达水平的差异,组间两两比较采用LSD-t检验。结果乳腺癌组织中miRNA-223与miRNA-29c的表达水平均明显低于癌旁组织(miRNA-223:2.27±0.75比9.34±3.24,miRNA-29c:0.69±0.40比2.58±0.75,t=6.763、11.354,均P0.001);miRNA-223与miRNA-29c在乳腺癌组织中呈正相关关系(r=0.737,P0.001);乳腺癌组织中miRNA-223表达与肿瘤部位有关,左侧乳腺癌患者miRNA-223表达水平高于右侧乳腺癌患者(t=2.032,P=0.046),但miRNA-29c表达与乳腺癌患者肿瘤部位无关(t=-0.587,P=0.559);并且,乳腺癌组织中miRNA-223和miRNA-29c表达与患者年龄、肿瘤直径、淋巴结转移、TNM分期以及ER、PR、HER-2、Ki67、p53表达均无关系(t=-0.079、0.220,-0.227、0.899,-1.355、-0.544,-1.482、-0.338,-0.487、0.429,0.395、1.432,-1.432、-1.318,-0.049、-0.307,-0.330、1.234,P均0.050)。miRNA-223在乳腺癌细胞株MDA-MB-231、MCF-7和SKBR3中的表达水平分别为2.16±0.28、0.93±0.24和0.57±0.15,3组间差异有统计学意义(F=39.224,P0.001),其中,miRNA-223在高侵袭性乳腺癌细胞株MDA-MB-231中的表达水平显著高于MCF-7和SKBR3(P均0.050);并且,miRNA-29c在乳腺癌细胞株MCF-7、MDA-MB-231和SKBR3中的表达水平分别为0.54±0.04、0.44±0.06和0.41±0.04,3组间差异也有统计学意义(F=6.652,P=0.030),其中,miRNA-29c在弱侵袭性乳腺癌细胞株MCF-7中的表达水平高于MDA-MB-231和SKBR3(P=0.034、0.013)。结论 miRNA-223和miRNA-29c可作为乳腺癌辅助诊断潜在的生物标志物,并且,两者与乳腺癌的分子分型相关。     

Effects of cycloheximide on the induction of CYP1A1 gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in three human breast cancer cell lines

Treatment of MCF-7, MDA-MB-231 and Hs578-T human breast cancercell lines with 10_–9 M 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD) induces CYP1A1 gene expression in the MCF-7 but not inthe MDA-MB-231 or Hs578-T cells. Pretreatment of the cells with10_–5 M cycloheximide results in significantly increasedP4501A1 mRNA levels in all three cells lines. However, in cellsco-treated with 10_–5 M cycloheximide plus 10_–9 MTCDD, an induced response by TCDD was observed in the MCF-7and MDA-MB-231 but not in Hs578-T cells. Gel-retardation assaysof nuclear extracts from the three cell lines complexed witha ³²P-labeled dioxin-responsive element (DRE) gave a TCDD-inducibleretarded band only in the MCF-7 and MDA-MB-231 cells. A retardedband with a similar mobility was observed in nuclear extractsfrom Hs578-T cells treated with either 10_–9 M TCDD orDMSO (solvent control). These results suggest that aryl hydrocarbonnon-responsive MDA-MB-231 and Hs578-T human breast cancer celllines contain the CYP1A1 gene and treatment with cycloheximideincreases both constitutive and TCDD-induced CYP1A1 gene expression.     

A molecular role for lysyl oxidase in breast cancer invasion

We identified previously an up-regulation in lysyl oxidase (LOX) expression,an extracellular matrix remodeling enzyme, in a highly invasive/metastatic human breast cancer cell line, MDA-MB-231, compared with MCF-7, a poorly invasive/nonmetastatic breast cancer cell line. In this study, we demonstrate that the mRNA expression of LOX and other LOX family members [lysyl oxidase-like (LOXL), LOXL2, LOXL3, and LOXL4] was observed only in breast cancer cells with a highly invasive/metastatic phenotype but not in poorly invasive/nonmetastatic breast cancer cells. LOX and LOXL2 showed the strongest association with invasive potential in both highly invasive/metastatic breast cancer cell lines tested (MDA-MB-231 and Hs578T). To determine whether LOX is directly involved in breast cancer invasion, LOX antisense oligonucleotides were transfected into MDA-MB-231 and Hs578T cells, and found to inhibit invasion through a collagen IV/laminin/gelatin matrix in vitro compared with LOX sense oligonucleotide-treated and untreated controls. In addition, treatment of MDA-MB-231 and Hs578T cells with beta-aminopropionitrile (an irreversible inhibitor of LOX enzymatic activity) decreased invasive activity. Conversely, MCF-7 cells transfected with the murine LOX gene demonstrated a 2-fold increase in invasiveness that was reversible by the addition of beta-aminopropionitrile in a dose-dependent manner. In addition, endogenous LOX mRNA expression was induced when MCF-7 cells were cultured in the presence of fibroblast conditioned medium or conditioned matrix, suggesting a role for stromal fibroblasts in LOX regulation in breast cancer cells. Moreover, the correlation of LOX up-regulation and invasive/metastatic potential was additionally demonstrated in rat prostatic tumor cell lines, and human cutaneous and uveal melanoma cell lines. These results provide substantial new evidence that LOX is involved in cancer cell invasion.     

The role of the polyamine catabolic enzymes SSAT and SMO in the synergistic effects of standard chemotherapeutic agents with a polyamine analogue in human breast cancer cell lines

Introduction

Polyamine analogues have demonstrated significant activity against human breast cancer cell lines as single agents as well as in combination with other cytotoxic drugs. This study evaluates the ability of a polyamine analogue N ¹,N ¹¹-bis(ethyl)norspermine (BENSpm) to synergize with six standard chemotherapeutic agents, 5-fluorouracil (FU), fluorodeoxyuridine, cis-diaminechloroplatinum(II) (C-DDP), paclitaxel, docetaxel, and vinorelbine.

Materials and methods

Four human breast cancer cell lines (MDA-MB-231, MCF-7, Hs578t, and T47D) and one immortalized, non-tumorigenic mammary epithelial cell line (MCF-10A) were used for in vitro combination studies with BENSpm and cytotoxic drugs. Xenograft mice models generated with MDA-MB-231 cells were used for in vivo studies with BENSpm and paclitaxel.

Results and conclusion

BENSpm exhibited synergistic inhibitory effect on cell proliferation in combination with 5-FU or paclitaxel in human breast cancer cell lines (MDA-MB-231 and MCF-7) and was either antagonistic or less effective in the non-tumorigenic MCF-10A cell line. Synergism was highest with 120 h concomitant treatment or pre-treatment with BENSpm for 24 h followed by concomitant treatment for 96 additional hours. Since the cytotoxic effects of many polyamine analogues and cytotoxic agents are believed to act, in part, through induction of the polyamine catabolic enzymes SSAT and SMO, the role of these enzymes on synergistic response was evaluated in MDA-MB-231 and MCF-7 treated with BENSpm and 5-FU or paclitaxel. Combination treatments of BENSpm with 5-FU or paclitaxel resulted in induction of SSAT mRNA and activity in both cell lines compared to either drug alone, while SMO mRNA and activity were increased only in MDA-MB-231 cells. Induction was greater with BENSpm/paclitaxel combination than BENSpm/5-FU. Further, RNAi studies demonstrated that both SSAT and SMO play a significant role in the response of MDA-MB-231 cells to treatment with BENSpm and 5-FU or paclitaxel. In MCF-7 cells, only SSAT appears to be involved in the response to these treatments. In an effort to translate combination studies from in vitro to in vivo, and to form a basis for clinical setting, the in vivo therapeutic efficacy of BENSpm alone and in combination with paclitaxel on tumor regression was evaluated in xenograft mice models generated with MDA-MB-231 cells. Intraperitoneal exposure to BENSpm or taxol singly and in combination for 4 weeks resulted in significant inhibition in tumor growth. These findings help elucidate the mechanisms involved in synergistic drug response and support combinations of polyamine analogues with chemotherapeutic agents which could potentially be used in the treatment of breast cancer.     

Stable transfection and overexpression of metallothionein isoform 3 inhibits the growth of MCF-7 and Hs578T cells but not that of T-47D or MDA-MB-231 cells

The third isoform of metallothionein (MT-3) is overexpressed in some breast cancers and its expression is associated with a poor disease outcome. In the PC-3 prostate cancer cell line, MT-3 expression has been shown to inhibit cell growth and increase drug resistance. The goal of the present study was to determine if MT-3 overexpression would influence the growth of human breast cancer cell lines. To determine this, the coding sequence of the MT-3 gene was stably transfected into two estrogen receptor positive (MCF-7 and T-47D) and two estrogen receptor negative cell lines (Hs578T and MDA-MB-231) having no basal expression of MT-3. Cell growth was determined by counting DAPI-stained nuclei, cadmium resistance by the colony formation assay, MT mRNA expression by RT-PCR, and MT protein by immuno-blot. It was demonstrated that MCF-7 and Hs578T cells that overexpress the MT-3 gene were growth inhibited compared to untransfected cells. In contrast, T-47D and MDA-MB-231 cells that overexpress MT-3 were not growth inhibited. Stable transfection of the MT-1E gene had no effect on the growth of any of the four cell lines. It was also demonstrated that the overexpression of both MT-3 and MT-1E only increased the resistance of MCF-7 cells to Cd⁺². In all instances, stable transfection of the MT-3 or MT-1E gene had no effect on the expression of the other MT isoforms. The study shows that MT-3 can influence the growth of some breast cancer cell lines.     

Midkine表达水平对人乳腺癌MDA．MB一231细胞转移潜能影响研究

目的：观察中期因子（midkine,MK）基因对人乳腺癌MDA—MB-231细胞增殖、迁移、黏附和侵袭能力的影响。方法：实时荧光定量PCR和蛋白质印迹法检测人乳腺癌细胞株MCF-7、Bcap-37和MDA-MB-231中MKmRNA及蛋白表达,筛选出MK表达丰度较高的细胞株。采用脂质体2000将MKshRNA干扰质粒pSilencer-3．1-H1一MK和空载体对照质粒pSilencer-3．1-H1-NC转染到该细胞株,并设未处理对照组。实时荧光定量PCR和蛋白质印迹法检测干扰后MK基因和蛋白表达;CCK一8检测细胞增殖能力,与胞外基质蛋白作用30min后检测其黏附能力,Transwell检测细胞侵袭能力和迁移能力。结果：实时荧光定量PCR和蛋白质印迹检测结果显示,MDA—MR231细胞株适合做敲减验证。pSilencer-3．1-H1-MK干扰MDA—MB231细胞MK表达后,MK基因相对表达量为0．384-0．02,低于对照组0．76±0．04和空载体转染组0．84±0．04,F=144．85,P〈0．001;MK蛋白相对表达量为0．39±0．07,低于对照组0．95±0．04和空载体转染组0．99±0．02,F=26．49,P=0．001。CCK-8结果显示,细胞培养24、48和72h,MK基因干扰组细胞增殖能力明显低于低于对照组和空载体转染组,差异有统计学意义,P〈0．05。细胞黏附实验结果显示,与胞外基质蛋白作用30rain后,MK基因干扰组黏附细胞数为（21．87±5．17）％,低于对照组（38．74±4．98）％和空载体转染组（42．37±5．74）％,F=27．60,P〈0．001。Transwell迁移实验中,MK基因干扰组穿越Transwell小室的细胞个数为26．6±6．67,低于对照组（47．0±4．32）和空载体转染组（52．0±6．98）,F：44．98,P〈0．001。侵袭实验中,MK基因干扰组穿越Tr—answell小室的细胞个数为13．2±3．46,低于对照组（19．4±4．43）和空载体转染组（19．9±3．90）,F=8．94,P=0．001。结论：干扰MK的表达可显著抑制人乳腺癌MDA—MB-231细胞体外增殖     

抑制CC类趋化因子配体5基因表达对乳腺癌细胞增殖能力的影响

目的 探讨抑制CC类趋化因子配体5(CCL5)基因表达对人乳腺癌细胞增殖能力的影响.方法 用特异性CCL5 RNA干扰(RNAi)序列慢病毒载体感染人乳腺癌细胞MCF-7和MDA-MB-231,分别为KD1组和KD2组;另在MCF-7和MDA-MB-231细胞中分设阴性病毒载体感染的阴性对照组(NC1组和NC2组)和未感染组(CON1组和CON2组).采用实时定量逆转录聚合酶链反应(RT-PCR)检测转染病毒后乳腺癌细胞中CCL5的表达,四甲基偶氮唑蓝(MTT)比色法和流式细胞术(FACS)分析细胞的增殖情况,平板克隆形成实验观察细胞的克隆形成能力.结果 CCL5 RNAi慢病毒可显著降低MCF-7和MDA-MB-231细胞中CCL5基因的表达.MTF法检测结果显示,在不同的培养时间,MCF-7和MDA-MB-231细胞的KD组、NC组与CON组细胞培养上清A值差异均无统计学意义(均P＞0.05).FACS分析结果显示,KD1组、NC1组和CON1组的增殖指数(PI)值分别为0.48±0.03、0.43±0.01和0.45±0.02;KD2组、NC2组和CON2组的PI值分别为0.48±0.02、0.44±0.05和0.47±0.02(两两比较,均P＞0.05).荧光显微镜下观察显示,KD组的克隆体积及每克隆的细胞数明显小于NC组和CON组.KD1组和KD2组克降数目(0.34±0.08和0.33±0.10)明显少于NC1组(0.81±0.12)、NC2组(0.97±0.09)、CON1组(0.92±0.12)和CON2组(1.04±0.07),差异有统计学意义(P＜0.05).结论 CCL5基因的表达下调对乳腺癌MCF-7和MDA-MB-231细胞群体倍增时间无明显影响,但可显著降低细胞的克隆形成能力,从而使肿瘤细胞的恶性增殖受到抑制.

Abstract：

Objective To investigate the effect of suppression of CCI5 ligand gene on the proliferation of human breast cancer cells. Methods A lentiviral vector carrying a short interfering RNA (siRNA) targeting CCL5 was transfected into human breast cancer cell line MCF-7 and MDA-MB-231 cells.The expression of CCL5 mRNA in the cells was detected by real-time PCR. The proliferation of MCF-7 and MDA-MB-231 cells was assessed by MTT assay and FACS assay, and the colony formation ability of both cell lines were measured, respectively. Results Real time PCR showed a good knockdown effect of CCL5 in both cell-lines. Colony-forming assay showed that the ability of colony formation of MCF-7/CCL5-siRNA and MDA-MB-231/CCL5-siRNA was decreased markedly. The colony number of MCF-7/CCL5-siRNA group was (0. 34 ± 0. 08), significantly lower than 0. 81 ± 0. 12 in the MCF-7/CCL5-N group and 0.92 ± 0.12 in the MCF-7 group (P ＜ 0. 05). The colony number of MDA-MB-231/CCL5-siRNA group was 0. 33 ± 0. 10,significantly lower than 0.97 ±0.09 in the MDA-MB-231/CCL5-N group and 1.04 ±0.07 in the MDA-MB-231 group (P ＜0.05). However, MTT assay revealed that the proliferation of MCF-7/CCL5-siRNA cells was not significantly different from that of MCF-7/CCL5-N or MCF-7 cells, respectively (P ＞0.05), and the same result was found in MDA-MB-231 cells. FACS assay showed that the proliferation index (PI) of groups MCF-7/CCL5-siRNA, MCF-7/CCL5-N and MCF-7 were 0.48 ± 0. 03, 0. 43 ± 0. 01 and 0.45 ±0. 02. The PI of groups MDA-MB-231/CCL5-siRNA, MDA-MB-231/CCL5-N and MDA-MB-231 cells were 0. 48 ± 0.02, 0.44 ± 0.05 and 0. 47 ± 0. 02. There was no statistical difference among them ( P ＞ 0.05 ).Conclusion The down-regulation of CCL5 gene in human breast cancer cells may significantly suppress their colony formation ability, rather than affecting their population doubling time to some extent.     

免疫金纳米笼子介导热疗诱导人乳腺癌细胞凋亡研究

目的：研究抗体修饰的金纳米笼子对乳腺癌细胞的光热杀伤作用。方法：由银（Ag）立方纳米晶与次氯金酸（HAuCl4）置换反应得到金纳米笼子,经Anti-CK19抗体修饰后制成具有生物靶向性的免疫金纳米笼子。将其链接细胞后,由激光照射,在荧光显微镜下观察免疫金纳米笼子光热杀伤乳腺癌细胞的效果,通过流式细胞仪检测其对乳腺癌细胞株MCF-7、MDA-MB-231和MCF-7/TMA热疗效果的差异,用免疫组化方法检测热疗后细胞内Caspase-9蛋白的表达量,MMT比色法观察其细胞毒性。结果：免疫金纳米笼子可以通过光热作用来杀伤乳腺癌细胞;MCF-7细胞株对照组凋亡率为（0.056±0.007 8）%,实验组为（50.2±4.56）%,MCF-7/TAM细胞株对照组凋亡率为（0.006 3±0.005 4）%,实验组为（52.6±5.07）%,MDA-MB-231细胞株对照组凋亡率为（0.054±0.006 4）%,实验组为（49.0±4.81）%,差异无统计学意义,F=0.84,P=0.456;Caspase-9蛋白在37℃时表达水平为0.06±0.02,41℃表达水平为0.15±0.04,43℃表达水平为0.34±0.04,对照组光照后温度为34℃,表达水平为0.05±0.01,〈43℃时,随着温度的升高Caspase-9的表达量明显升高,F=14.914,P〈0.001;MMT法结果显示,高剂量免疫金纳米笼子可抑制乳腺癌细胞的增殖（F=5.774,P〈0.001）,且存在时间-效应（F=42.378,P〈0.001）和剂量-效应（F=76.440,P〈0.001）关系。结论：免疫金纳米笼子介导的光热疗法可以靶向杀伤乳腺癌细胞,上调Caspase-9的表达,是免疫金纳米笼子介导的热疗诱导乳腺癌细胞凋亡的机制之一。