抑癌基因PTEN对乳腺癌ZR-75-1细胞增殖和转移的抑制作用

背景与目的:研究表明,抑癌基因PTEN不仅能抑制肿瘤细胞的增殖,还能抑制其转移,但其机理还不甚明了.本文研究抑癌基因PTEN对人乳腺癌ZR-75-1细胞增殖和转移的作用.方法:以脂质体介导法分别将野生型PTEN质粒和磷酸酶缺陷的PTEN质粒转染人乳腺癌ZR-75-1细胞,用MTT法测定细胞增殖抑制率:转染后用嘌呤霉素筛选阳性克隆.用Western blot法检测细胞中PTEN蛋白的表达.通过细胞-基质粘附实验和人工重组基底膜侵袭实验,检测细胞粘附抑制率与侵袭抑制率.结果:野生型PTEN质粒转染的ZR-75-1细胞增殖明显被抑制,并伴有部分细胞凋亡;该细胞与未经转染的和磷酸酶缺陷的PTEN质粒转染的ZR-75-1细胞比较.细胞增殖抑制率差异均有统计学意义(42.7% vs.0%及2.7%,P＜0.01),细胞增殖抑制效应随细胞培养时间与质粒浓度的增加而增强.而磷酸酶缺陷的PTEN质粒转染的与未经质粒转染的ZR-75-1细胞比较,细胞增殖抑制率差异无统计学意义(2.7%vs.0%,P＞0.05).在两种PTEN质粒转染的ZR-75-1细胞中PTEN蛋白均明显表达,其中转染野生型PTEN质粒的细胞的粘附抑制率与侵袭抑制率分别达65.7%和70.4%,而转染磷酸酶缺陷的PTEN质粒的ZR-75-1细胞的粘附抑制率与侵袭抑制率分别只有8.8%和6.9%(P＜0.05).结论:具有双特异磷酸酶活性的野生型PTEN基因对ZR-75-1细胞的增殖和转移有一定的抑制作用.     

PTEN磷酸酶活性对乳腺癌细胞ZR-75-1迁移能力的影响

目的:探求PTEN蛋白的磷酸酶活性对乳腺癌细胞ZR-75-1转移能力的影响。方法:采用脂质体介导法分别将野生型PTEN质粒(wt-PTEN)、磷酸酶失活的PTEN质粒(G129R-PTEN)和只具有蛋白磷酸酶活性的PTEN质粒(G129E-PTEN)转染PTEN基因缺失的人乳腺癌细胞株ZR-75-1,Western印迹法检测PTEN蛋白及P397-FAK的表达水平,体外细胞划痕实验观察PTEN磷酸酶活性对ZR-75-1细胞迁移能力的影响,细胞基质黏附试验和人工重组基底膜侵袭试验测定PTEN质粒转染和未转染的ZR-75-1细胞的黏附抑制率和侵袭抑制率,免疫组化法检测MMP-2的水平。结果:wt-PTEN、G129R-PTEN及G129E-PTEN3种质粒均成功转染ZR-75-1细胞并有PTEN蛋白的表达,其中wt-PTEN、G129E-PTEN均能抑制ZR-75-1细胞迁移;wt-PTEN和G129E-PTEN转染细胞之间的黏附抑制率和侵袭抑制率或侵袭细胞相对数均无显著性差异,但与G129R-PTEN转染的和未经转染的ZR-75-1细胞相比有显著性差异(P<0.01)。wt-PTEN和G129E-PTEN质粒转染的ZR-75-1细胞其P397-FAK水平均显著低于G129R-PTEN质粒转染的ZR-75-1细胞;wt-PTEN与G129E-PTEN质粒转染的ZR-75-1细胞MMP-2水平对比于G129R-PTEN质粒转染的和未经质粒转染的ZR-75-1细胞有显著性差异(P<0.01)。结论:具有双特异磷酸酶活性的野生型PTEN基因和只具蛋白磷酸酶活性的PTEN基因均能抑制乳腺癌细胞ZR-75-1的迁移,而磷酸酶失活的PTEN基因则无此作用。     

抑癌基因PTEN抑制乳腺癌ZR-75-1细胞转移作用机制的探讨

目的 探讨抑癌基因PTEN抑制乳腺癌细胞ZR-75-1转移的作用机制.方法 用脂质体介导法分别将野生型PTEN质粒(wt)、磷酸酶活性缺失的PTEN质粒(G129R)和只具蛋白磷酸酶活性的PTEN质粒(G129E)转染PTEN基因缺失的乳腺癌细胞ZR-75-1.转染细胞以嘌呤霉素筛选后,用PCR和Western-blot分别检测PTEN基因及其蛋白;通过黏附、侵袭实验,比较3种质粒转染细胞和未转染细胞之间的黏附、侵袭能力的差异;用Western-blot法检测各组转染细胞总的黏着斑激酶(FAK)和磷酸化黏着斑激酶(P397-FAK)的表达水平;以免疫组化法检测基质金属蛋白酶-2(MMP-2)和E-钙连素(E-Cd)的表达,并用RT-PCR检测各组转染细胞的p53mRNA水平.结果 3种质粒均成功转染ZR-75-1细胞,并证实3种转染细胞内均有PTEN基因存在及PTEN蛋白表达;wt、G129R、G129E等 3种质粒转染的细胞黏附抑制率分别为65.7%、8.8%和43.5%;侵袭抑制率分别为70.4%、6.9% 和63.5%.将wt或G129E转染细胞的黏附抑制率及侵袭抑制率与G129R转染细胞的比较,均有显著性差异(P＜0.05);但wt与 G129E转染细胞比较,均无显著性差异(P＞0.05 ).3种转染细胞总FAK水平虽无显著性差异(P＞0.05 ),但wt和G129E转染细胞其P397-FAK和 MMP-2水平都显著低于G129R转染细胞(P＜0.05).3种转染细胞间的E-Cd水平未见显著差异.RT-PCR分析显示,wt、G129E和G129R 3种转染细胞p53 mRNA水平无显著性差异,但均显著高于未转染细胞.结论 野生型PTEN基因所表达的蛋白具脂质和蛋白双特异磷酸酶活性,对乳腺癌细胞ZR-75-1的转移具有抑制作用,其机制与磷酸酶活性有关,其中蛋白磷酸酶活性可能起主要作用.     

野生型PTEN基因在乳腺癌细胞中对表阿霉素的增敏作用

目的探讨野生型PTEN基因在人乳腺癌细胞系MCF-7和ZR-75-1中对表阿霉素的增敏作用。方法腺病毒介导野生型PTEN基因导入人乳腺癌细胞系MCF-7和ZR-75-1,RT-PCR检测PTEN mRNA的表达,Western blot检测转染后PTEN蛋白的表达;Ad-PTEN感染联合不同浓度的表阿霉素处理细胞,采用CCK-8法测定细胞增殖抑制率和联合效应。结果腺病毒介导的PTEN基因导入法可明显地增加细胞中PTEN基因的表达,野生型PTEN 基因转染联合表阿霉素使乳腺癌细胞MCF-7对表阿霉素的敏感度增加了两倍,而使乳腺癌细胞ZR-75-1对表阿霉素的敏感度增加了十倍。结论腺病毒重组的野生型PTEN基因联合表阿霉素对人乳腺癌细胞增殖具有显著的协同抑制效应。     

抑癌基因PTEN的表达对大肠癌细胞转移侵袭能力的影响

目的探讨抑癌基因PTEN的表达大肠癌细胞转移侵袭能力的影响.方法1.利用western blot法检测不同转移潜能的大肠癌细胞系内PTEN蛋白的表达水平,说明PTEN蛋白的表达对大肠癌细胞转移潜能的影响,2.用脂质体作载体,将PTEN基因转染大肠癌细胞株LOVO后,采用计数细胞悬液加到粘附底物后20 min和120 min的细胞贴壁数用以测定细胞粘附能力,采用Costar的浸润小室检测PTEN基因转染前后细胞的浸润能力.结果1.转移潜能高的LOVO细胞PTEN的表达量显著低于转移潜能较低的HT-29,LS-174T,2.未转染细胞(LOVO)、转染pcDNA3.0-PTEN的细胞(LOVO/pcD-NA3.0-PTEN)在特异性粘附底物(Laminin)上20 min时贴壁率分别为18.6%±1.4%和13.9%±0.48%(P＜0.05),120min时贴壁率分别为71.2%±2.5%和56.0%±1.6%(P＜0.05),3.采用Costar的浸润小室对LOVO、LOVO/pcDNA3.0-PTEN细胞的浸润能力分析结果显示细胞悬液静置培养6 h后,对照细胞LOVO浸润穿透多聚碳膜的细胞数为11.7±1.74个,LOVO/pcDNA3.0-PTEN细胞穿透多聚碳膜的细胞数为7.5±1.58个(P＜0.05).结论在肿瘤细胞内抑癌基因PTEN的表达与大肠癌的转移侵袭行为密切相关.     

野生型PTEN基因高表达对膀胱移行细胞癌EJ细胞的抑癌作用

目的 探讨外源性野生型人酪氨酸磷酸酶（PTEN）基因的高表达对膀胱移行细胞癌EJ细胞的抑癌作用。方法 利用携带人PTEN基因的野生型、磷酸酶域突变型质粒体外分别转染人膀胱移行细胞癌EJ细胞。Western blot检测目的基因PTEN的表达,观察细胞形态变化及超微结构变化;MTIO法检测细胞增殖率及转染细胞对吡柔比星（THP）和丝裂霉素（MMC）的敏感性;Western blot法检测bcl-2蛋白的表达。以空载质粒作为对照。结果 质粒转染后,EJ细胞的PTEN蛋白表达上升75．0％。转染野生型质粒后,EJ细胞异型性低,出现典型凋亡小体,细胞增殖率下降40．1％,bcl-2蛋白表达被下调,并提高了对THP和MMC的敏感性。而转染突变型质粒的EJ细胞则无此作用。结论 野生型PTEN基因在体外对膀胱移行细胞癌EJ细胞增殖有明显抑制作用,诱导细胞凋亡,磷酸酶域突变型PTEN基因无此作用。野生型PTEN的抑癌作用可能与其对bcl-2蛋白表达的下调有关。     

塔斯品碱衍生物TPD7对乳腺癌细胞迁移和侵袭的抑制作用

目的:探讨塔斯品碱衍生物TPD7对乳腺癌细胞MCF-7和ZR-75-30细胞迁移和侵袭的影响,阐明TPD7抑制细胞迁移和侵袭可能的作用机制。方法:采用细胞划痕法、Transwell小室侵袭法检测MCF-7和ZR-75-30细胞的迁移和侵袭。采用Western blot法检测MMP9、β-catenin及c-Myc的蛋白表达。RT-PCR法检测β-catenin及c-Myc的mRNA表达。结果:TPD7对MCF-7细胞和ZR-75-30细胞迁移和侵袭均有显著抑制作用,且下调MMP9、β-catenin、c-Myc的蛋白表达和mRNA表达,呈剂量依赖性。结论:TPD7抑制乳腺癌MCF-7和ZR-75-30细胞迁移和侵袭,可能是通过Wnt信号通路抑制上皮-间质转化。     

5-Aza-CdR诱导抑癌基因PTEN重新表达对乳腺癌细胞的影响及机制

目的观察5-氮杂-2’-脱氧胞苷(5-Aza-CdR)对人乳腺癌细胞系MCF-7增殖、凋亡及体外侵袭能力的影响并初步探讨其机制。方法体外培养MCF-7细胞,采用不同浓度的5-Aza-CdR(1×10-6、2×10-6、5×10-6和1×10-5mol/L)分别作用24h、48h和72h,分别采用MTT法检测细胞增殖抑制率、流式细胞仪检测细胞凋亡、Transwell法检测细胞侵袭能力、Western-blot检测PTEN和VEGF-C蛋白表达的变化。结果经不同浓度的5-Aza-CdR作用后,MCF-7细胞的增殖受到不同程度的抑制并发生凋亡,细胞侵袭能力也发生不同程度的降低,且其作用随浓度增加和时间延长而增强(P<0.05)。在5-Aza-CdR作用后,MCF-7细胞PTEN的表达逐渐增强,而VEGF-C的表达逐渐减弱。结论 5-Aza-CdR可抑制乳腺癌细胞增殖、诱导其发生凋亡、降低其体外侵袭能力,其可能是通过去甲基化作用使抑癌基因PTEN重新表达并下调VEGF-C的表达而发挥作用的。     

抑癌基因PTEN在乳腺癌中的表达及意义

目的　研究一种新的抑癌基因PTEN在乳腺癌中的表达及意义。方法　应用免疫组织化学SP法 ,检测了 2 8例乳腺癌及2 1例癌旁乳腺组织PTEN蛋白的表达 ;EnVision法检测癌组织中雌、孕激素受体的表达。结果　 2 1例癌旁乳腺组织中均有PTEN蛋白的表达 ,免疫组化染色较强 ,阳性物质位于乳腺小叶腺泡上皮细胞及导管上皮细胞的胞质和胞核。在乳腺癌组织中PTEN蛋白表达于癌细胞的胞质和胞核 ,2 8例乳腺癌组织中PTEN蛋白的表达不同。 14 .2 8%乳腺癌组织无PTEN蛋白的表达 ;2 1.4 %乳腺癌组织PTEN蛋白呈弱阳性 ;6 4 .2 8%乳腺癌组织中有较强的PTEN蛋白表达 ,表达强度与正常乳腺组织无明显差异。此外 ,PTEN蛋白的表达与乳腺癌的临床病理学特点相关 ,PTEN蛋白阴性的乳腺癌 ,2 5 %为雌、孕激素受体阳性 ;而PTEN蛋白表达较强的乳腺癌 ,6 6 .6 7%为雌、孕激素受体阳性 ,且差异有显著性 (P <0 .0 5 )。另外 ,PTEN蛋白阳性的乳腺癌组织 ,腋窝淋巴结转移率为 2 2 .2 % ;而PTEN蛋白阴性的乳腺癌腋窝淋巴结转移率为 75 % ,差异有显著性 (P <0 .0 5 )。结论　乳腺癌组织中存在着抑癌基因PTEN的表达缺失和减弱 ,抑癌基因PTEN的表达异常可能与乳腺癌的发生、发展及预后有关。     

PTEN蛋白在乳腺癌组织中的表达及其临床意义

目的 探讨抑癌基因PTEN在乳腺癌组织中的表达及其临床意义。方法 采用SABC免疫组织化学方法，检测了62例乳腺癌、15例癌旁及12例正常乳腺组织中PTEN蛋白表达水平，结合临床病理指标进性分析。结果 乳腺癌组PTEN蛋白阳性表达率（56．5％）显著低于癌旁组（86．7％）和正常组（100．0％），P均〈0．05；癌旁组（86．7％）低于正常组（100．0％），P〉0．05。伴有淋巴结转移的乳腺癌中PTEN蛋白阳性表达率（32．1％）显著低于无淋巴结转移乳腺癌（61．8％），P〈0．05；浸润性癌PTEN蛋白阳性表达率（44．4％）显著低于早期浸润性癌（75．0％），P〈0．05；PTEN蛋白表达与肿瘤大小、PTNM分期无关，P〉0．05。结论 PTEN蛋白在乳腺癌的发生、发展、侵袭转移中可能起着重要作用。PTEN蛋白表达水平可以作为判定乳腺癌病理生物学行为的客观指标。     

A novel taspine derivative,HMQ1611, suppresses adhesion,migration and invasion of ZR-75-30 human breast cancer cells

Background

Taspine was screened for the first time from Radix et Rhizoma leonticis (Hong Mao Qi in Chinese) using cell membrane chromatography in our laboratory. Its anticancer and antiangiogenic properties were demonstrated, and it could serve as a lead compound in anticancer agent development. Here, we investigated the role of one of the derivatives, HMQ1611, with increased activity and solubility, on the regulation of breast cancer cell ZR-75-30 adhesion, migration and invasion.

Methods

The effect of HMQ1611 on adhesion, invasion and migration of human breast cancer cells ZR-75-30 was examined. The migration and invasive potential of ZR-75-30 cells were examined by wound-healing assays and matrigel invasion chamber assays. The adhesion to type IV collagen and laminin were evaluated by MTT assay. The expression and proteinase activity of two matrix metalloproteinases (MMPs), matrix metalloproteinases 2 (MMP-2) and matrix metalloproteinases 9 (MMP-9), were analyzed by Western blot analysis and gelatin zymography, respectively.

Results

HMQ1611 effectively inhibited ZR-75-30 cell invasion and significantly suppressed adhesion to type IV collagen and laminin-coated substrate in a dose-dependent manner. Western blot and gelatin zymography analysis showed that HMQ1611 significantly inhibited the expression and secretion of MMP-2 and MMP-9 in ZR-75-30 cells. Additionally, treatment of ZR-75-30 cells with HMQ1611 downregulated the expression of MMP-2 and MMP-9.

Conclusions

HMQ1611 had potential to suppress the adhesion, migration and invasion of ZR-75-30 cancer cells, and it could serve as a potential novel therapeutic candidate for the treatment of metastatic breast cancer.     

Reversal of the malignant phenotype of ovarian cancer A2780 cells through transfection with wild-type PTEN gene

Objective

PTEN (phosphatase and tensin homologue deleted on chromosome 10) is a tumor suppressor gene identified on human chromosome 10q23. Substantial studies have demonstrated that PTEN can inhibit cell proliferation, migration and invasion of many cancer cells. The purpose of this study was to determine whether upregulation of PTEN gene by transfection wild-type PTEN gene to ovarian cancer cells can inhibit growth and migration and to explore the potential for PTEN gene therapy of ovarian cancers.

Method

Wild-type and phosphatase-inactive (C124A) PTEN plasmids were transfected into ovarian epithelial cancer A2780 cells, and their effects on cell apoptosis, cell proliferation, cell migration and cell invasion were analyzed by flow cytometry analysis, TUNEL assay, MTT assay, wound-healing assay and transwell assay.

Results

Both wild-type and mutant PTEN can upregulate the expression of PTEN gene dramatically; however, it is wild-type PTEN not phosphatase-inactive PTEN that can induce apoptosis and decrease cell migration, invasion and proliferation in ovarian cancer cells.

Conclusion

These results demonstrated that PTEN had played an important role in the cell proliferation, cell migration and invasion dependent on its phosphatase activity. Enhanced expression of PTEN by gene transfer is sufficient to reverse the malignant phenotype of ovarian cancer cells and transfection of ovarian cancer cells with wild-type PTEN gene might be another novel approach for therapeutic intervention in ovarian cancer.     

乳腺癌干细胞富集与鉴定的初步研究

目的:通过从MCF-7、ZR-75-1、MDA-MB-231乳腺癌细胞系中培养富集及鉴定乳腺癌干细胞(breast cancer stem cell,BCSC),寻找培养与富集乳腺癌干细胞的方法。方法:贴壁培养MCF-7、ZR-75-1、MDA-MB-231细胞系,倒置显微镜观察各细胞形态;流式细胞仪分别分选收集CD44-CD24-、CD44-CD24+、CD44+CD24-及 CD44+CD24+ 细胞,其中CD44+CD24-为乳腺癌干细胞,其余三类为对照组;MTT法计数细胞,绘制MCF-7、ZR-75-1、MDA-MB-231细胞系生长曲线;MCF-7细胞系进行无血清悬浮培养1个周期,流式细胞仪检测分子表面标记物CD44+CD24-含量,贴壁培养的CD44+CD24-乳腺癌干细胞为对照组;将分选的MCF-7（CD44+CD24-）和分选的其余MCF-7细胞（非CD44+CD24-）进行干性成球实验,鉴定CD44+CD24-干性表达。结果:MCF-7、MDA-MB-231细胞系富含表面标志物CD44-CD24-的乳腺癌细胞;ZR-75-1细胞系富含分子表面标志物CD44+CD24+的乳腺癌细胞;生长曲线显示MCF-7、ZR-75-1、MDA-MB-231均呈持续增长,MDA-MB-231细胞生长较MCF-7、ZR-75-1细胞快;通过无血清悬浮培养CD44+CD24-乳腺癌干细胞由19.4%富集到88.9%;成球实验中CD44+CD24-表型细胞成球数量较分选的其余MCF-7细胞（非CD44+CD24-表型）明显增多,成球率分别为（36.5±1.7）%,（1.1±0.5）%。结论:流式细胞仪可成功分选出分子表面标志物为CD44+CD24-的乳腺癌干细胞;CD44+CD24-可能不是乳腺癌干细胞唯一的表面标志物;MDA-MB-231细胞系较MCF-7、ZR-75-1细胞系生长快;无血清悬浮培养法可简便、高效地富集乳腺癌干细胞;CD44+CD24-乳腺癌干细胞干性表达较强。     

Momordica cochinchinensis Seed Extracts Suppress Migration and Invasion of Human Breast Cancer ZR-75-30 Cells Via Down-regulating MMP-2 and MMP-9

Objective: Metastases and invasion are the main reasons for oncotherapy failure. Momordica cochinchinensis(Mu Bie Zi in Chinese) had been used for a variety of purposes, and shown anti-cancer action. In this article, wefocused on effects on regulation of breast cancer cell ZR-75-30 metastases and invasion by extracts of Momordicacochinchinensis seeds (ESMCs). Methods: Effect of ESMCs on ZR-75-30 human breast cancer cells proliferationwere evaluated by MTT assay and on invasion and migration by wound-healing and matrigel invasion chamberassays. Expression and protease activity of two matrix metalloproteinases (MMPs), MMP-2 and MMP-9, wereanalyzed by Western blotting and gelatin zymography, respectively. Results: ESMC revealed strong growthinhibitory effects on ZR-75-30 cells, and effectively inhibited ZR-75-30 cell invasion in a dose-dependent manner.Western blot and gelatin zymography analysis showed that ESMC significantly inhibited the expression andsecretion of MMP-2 and MMP-9 in ZR-75-30 cells. Conclusions: ESMC has the potential to suppress the migrationand invasion of ZR-75-30 cancer cells, and it might prove to of interest in the development of novel inhibitorsfor breast cancer.     

Bag1 proteins regulate growth and survival of ZR-75-1 human breast cancer cells

Bag1 proteins bind heat shock protein M(r) 70,000 (Hsp 70) family molecular chaperones and regulate diverse pathways involved in cell proliferation, apoptosis, and stress responses. Four isoforms of Bag1 can be produced from a single gene in humans, including a nuclear-targeted long version (Bag1L)and a shorter cytosolic isoform (Bag1). Because overexpression of Bag1and Bag1L has been reported in breast cancers, we explored the effects of Bag1 and Bag1L on the growth of ZR-75-1 human breast cancer cells cultured in vitro and in tumor xenograft models using immunocompromised mice. Cells stably transfected with expression plasmids encoding either Bag1 or Bag1L displayed comparable rates of growth in cultures containing 10% serum, compared with control-transfected ZR-75-1 cells. In contrast, ZR-75-1 cells stably expressing mutants of Bag1 or Bag1L, which lack the COOH-terminal domain (DeltaC) required for heat shock protein M(r) 70,000 binding, displayed retarded growth rates. When cultured without serum, the viability of control-transfected, as well as Bag1DeltaC- and Bag1LDeltaC-expressing, cells declined with time, whereas Bag1- and Bag1L-overexpressing ZR-75-1 cells survived for over a week in culture. Caspase protease activation induced by serum deprivation was also prevented by stable expression of either Bag1 or Bag1L in ZR-75-1 cells. In addition, sensitivity to anchorage dependence was restored partially in ZR-75-1 cells expressing dominant-negative Bag1DeltaC and Bag1LDeltaC. In tumor xenograft studies involving injection of ZR-75-1 cells into mammary fat pads of female nu/nu mice, ZR-75-1 cells expressing Bag1 or Bag1L formed 1.4-1.6-fold larger tumors compared with control-transfected cells, whereas tumors formed by Bag1DeltaC- and Bag1LDeltaC-expressing cells grew very slowly and reached sizes < one-third of tumors generated by Neo-control ZR-75-1 cells. Altogether, these findings demonstrate that Bag1 and Bag1L provoke similar changes in breast cancer cell growth and survival and suggest that interference with Bag1 or Bag1L function might be a useful strategy for opposing breast cancer.