OPN对卵巢癌Hey细胞增殖、迁移和侵袭能力的影响

目的:探讨骨桥蛋白(Osteopontin,OPN)对卵巢癌Hey细胞增殖、迁移和侵袭能力的影响及其可能涉及的分子机制。方法:选择卵巢癌细胞株Hey、HO8910、A2780和正常卵巢上皮细胞IOSE80,采用Western blot检测OPN蛋白的表达情况。对OPN表达量相对较高的Hey细胞株的OPN基因敲减或过表达,运用CCK-8、平板克隆实验、细胞划痕、Transwell侵袭实验等方法研究OPN对细胞增殖、迁移及侵袭能力的影响,采用Western blot检测Wnt/β-catenin通路相关蛋白β-catenin、CyclinD1、c-myc的表达情况。结果:OPN在卵巢癌细胞株Hey、HO8910、A2780内均有表达,且表达量均高于正常卵巢上皮细胞IOSE80。si RNA-OPN转染卵巢癌Hey细胞沉默OPN表达,CCK-8和平板克隆实验显示沉默OPN能够降低Hey细胞的增殖能力,划痕实验和Transwell侵袭实验显示下调OPN可降低Hey细胞的迁移和侵袭能力,Wnt/β-catenin通路相关蛋白β-catenin、CyclinD1、c-myc表达下降。ex-OPN转染Hey细胞使OPN表达升高,与对照组相比,OPN过表达能够增强Hey细胞的增殖、迁移和侵袭能力,并且Wnt/β-catenin通路相关蛋白β-catenin、CyclinD1、c-myc表达升高。结论:OPN能够促进卵巢癌细胞的增殖、迁移及侵袭能力,该作用可能通过促进Wnt/β-catenin信号通路实现。     

Vasorin基因稳定敲除HepG2细胞株的建立及其生物学功能研究

目的:利用CRISPR/Cas9技术建立人Vasorin(VASN)基因稳定敲除的HepG2细胞株,并研究VASN蛋白对细胞增殖和迁移等生物学功能的影响。方法:根据人VASN序列设计向导RNA,将其克隆至表达载体pCas-Guide,获得质粒pCas-gRNA;PCR扩增VASN编码基因左、右同源臂及潮霉素B抗性基因,通过重叠PCR将三者拼接为一条片段,并克隆至载体pBackZero-T,获得质粒pBackZero-T-VASN;上述2种重组质粒共转染HepG2细胞,经潮霉素B筛选,通过基因组PCR、RT-q PCR和Western印迹实验检测VASN基因是否被敲除。利用CCK-8法和Transwell法检测VASN稳定敲除细胞株的增殖和迁移能力。结果:向导RNA表达质粒pCas-gRNA和DNA供体质粒pBackZero-T-VASN构建成功;基因组PCR结果显示,潮霉素B基因正确重组至VASN基因中;RT-PCR显示VASN m RNA水平显著降低,Western免疫印迹结果显示VASN蛋白表达水平显著降低;VASN稳定敲除细胞株的增殖和迁移能力比野生型细胞明显减弱。结论:构建了pCas-gRNA和pBackZero-T-VASN质粒,获得了VASN缺失的细胞株,验证了VASN蛋白参与细胞的增殖和迁移过程,为深度探讨VASN的生物学功能及其分子机制奠定了基础。     

整合素β2促进人乳腺癌细胞MCF-7的迁移,侵袭与粘附

本研究主要目标为探讨整合素β2 (ITGB2)的高表达对人乳腺癌细胞MCF-7迁移,侵袭与粘附能力的影响。本研究首先构建了ITGB2过表达质粒,实验设阴性对照组(pcDNA-3.1+)与ITGB2基因过表达组(pcDNA-3.1+/ITGB2)。ITGB2过表达质粒转染MCF-7细胞后,采用逆转录PCR与Western blotting方法分别检测ITGB2 mRNA转录水平与蛋白翻译水平;流式细胞术检测细胞周期的改变;划痕实验检测细胞横向迁移能力;Transwell小室实验检测细胞纵向迁移能力及侵袭能力;人脐静脉血管内皮细胞(HUVEC)粘附实验检测癌症细胞与血管内皮细胞之间的粘附能力,Western blotting实验检测侵袭相关指标MMP9,整合素经典通路中FAK蛋白磷酸化水平的改变。研究结果表明:转染ITGB2过表达质粒后,MCF-7细胞中ITGB2的m RNA水平(p<0.01)与蛋白水平(p<0.05)均显著增高;流式细胞术实验中,实验组S期的细胞所占比例与对照组无明显差异;划痕实验与Transwell小室实验中,实验组的迁移侵袭能力显著性增强;人脐静脉血管内皮细胞粘附实验中,实验组乳腺癌细胞与血管内皮细胞的粘附能力强于对照组(p<0.05);且Western blotting结果显示MMP9和p-FAK蛋白水平明显上升。由以上结果可得出结论,过表达ITGB2后会增强人乳腺癌细胞MCF-7的迁移、侵袭与粘附能力,而对其增殖能力无明显影响。     

URI基因稳定表达对肝癌SMMC-7721细胞增殖能力的影响

目的:瞬转以及筛选出能够稳定表达URI(RPB5-mediating protein)基因的SMMC-7721细胞株,以其为模型研究URI基因对人肝癌SMMC-7721细胞增殖的影响.方法:首先,抽提URI的重组质粒并转染到SMMC-7721细胞中,在G418药物的筛选下选出能够稳定表达URI基因的细胞株,RT-PCR法和酶切检测该稳定细胞中URI基因的表达效率以确认URI是否稳定表达,MTT法和克隆形成实验检测URI基因对SMMC-7721细胞增殖的影响.结果:成功建立URI基因过表达的稳定细胞株.与SMMC-7721细胞对照组比较,其URI mRNA表达水平显著上调,能稳定表达URI细胞株的增殖,克隆形成率明显升高.结论:pFLAG-CMV-4-URI重组质粒能使URI在肝癌SMMC-7721细胞内稳定表达,过表达URI基因有可能帮助细胞通过G2/M期检验点来提高肝癌细胞SMMC-7721的增殖能力.     

蜕皮激素诱导MIIP基因的表达对肝癌细胞增殖迁移的影响

目的:探讨蜕皮激素诱导迁移侵袭抑制蛋白基因(migration and invasion inhibitory protein,MIIP)基因的表达对肝癌细胞SK-Hep-1增殖和迁移能力的影响。方法:采用PCR扩增MIIP基因,连入T载体测序正确后,插入到蜕皮激素可诱导真核表达载体pIND中。将pIND-MIIP和含蜕皮激素受体基因的表达载体pVgRXR以脂质体转染法转染到SK-Hep-1中,经G418和Zeocin双抗生素筛选获得稳定转染细胞株。蜕皮激素Ponasterone A诱导后,采用Western blot检测MIIP表达,CCK-8实验检测细胞增殖,划痕实验检测细胞迁移。结果:蜕皮激素诱导MIIP表达上调后,SK-Hep-1细胞的增殖能力显著下降(P0.05),细胞的迁移能力明显减弱。结论:建立了MIIP基因可诱导表达系统,证实在肝癌细胞SK-Hep-1中MIIP过表达可抑制细胞的增殖及迁移能力。     

上调OPN和TIP30表达对口腔鳞癌cal-27细胞的影响

目的:探讨上调骨桥蛋白(OPN)和TIP30表达对口腔鳞状细胞癌cal-27细胞增殖和迁移能力的影响。方法:采用过表达OPN载体病毒和过表达TIP30质粒分别感染或转染cal-27细胞株后,通过实时荧光定量PCR法和蛋白印迹western blot法检测OPN和TIP30的表达,CCK-8法检测细胞增殖能力,细胞划痕实验检测细胞的迁移能力。结果:过表达OPN载体病毒感染的cal-27-sh OPN细胞株OPN m RNA和蛋白的表达均明显高于cal-27-sh N细胞株(P0.001,P=0.002),且细胞的增殖能力和迁移能力强(P0.001,P=0.002)。过表达TIP30质粒转染的cal-27-p TIP30细胞株TIP30 m RNA和蛋白的表达均明显高于cal-27-pc3.0细胞株(P=0.001,P=0.003),且细胞的增殖能力和迁移能力弱(P0.001,P=0.005)。结论:OPN能促进cal-27细胞的增殖和迁移,TIP30抑制cal-27细胞的增殖和迁移。     

Caveolin-1抑制胰腺癌细胞PANC1的体内外生长和增殖

窖蛋白-1(caveolin-1)是胞膜窖(caveolae)中重要的结构和功能蛋白.Caveolin-1参与细胞的多种生命活动并与恶性肿瘤的发生相关.为探讨caveolin-1对胰腺癌细胞PANC1的体外增殖、迁移、侵袭以及裸鼠体内成瘤能力的影响,通过基因转染技术培育caveolin-1过表达细胞株PANC1/cav-1作为实验组,转染空载体细胞株PANC1/vector作为对照组,采用RT-PCR及Western blot方法检测caveolin-1的表达量,流式细胞术分析细胞周期,软琼脂细胞克隆实验检测细胞增殖能力,侵袭小室实验检测癌细胞迁移和侵袭的能力,建立裸鼠皮下种植瘤模型并检测肿瘤组织的增殖与凋亡.PANC1/cav-1中的caveolin-1表达稳定,表达量明显高于对照组细胞株和亲本细胞株(P<0.01),细胞周期检测显示大量PANC1/cav-1细胞被抑制于G0/G1期,caveolin-1抑制PANC1的增殖,迁移和侵袭能力.在裸鼠的体内实验中,caveolin-1显著抑制PANC1细胞在裸鼠体内的生长,Ki-67染色和TUNEL染色表明在PANC1细胞中过表达caveolin-1,可以抑制肿瘤增殖并诱导肿瘤凋亡.上述结果表明,caveolin-1可能通过对胰腺癌细胞周期的影响(抑制于G0/G1期),抑制胰腺癌PANC1细胞在体内外的增殖、迁移和侵袭,并导致肿瘤凋亡.     

靶向糖基转移酶shRNA表达质粒对LoVo细胞侵袭和增殖能力的抑制作用

通过构建针对Ｎ-乙酰氨基葡萄糖转移酶Ⅴ(GnT-Ⅴ)的小片段发夹状RNA(shRNA)干扰表达质粒,研究了shRNA表达质粒沉默GnT-Ⅴ基因后对LoVo细胞增殖、黏附以及迁移、侵袭能力的影响．设计了靶向GnT-Ⅴ基因的小干扰RNA(siRNA)靶序列,构建shRNA表达载体并转染人结肠癌LoVo细胞,通过G418筛选建立稳定低表达GnT-Ⅴ基因的细胞株．分别采用半定量逆转录聚合酶链反应(RT-PCR)和蛋白质印迹(Western blot)检测shRNA对GnT-Ⅴ基因mRNA及蛋白质表达的影响．并通过CCK-8增殖实验、异质黏附实验、划痕愈合实验、趋化运动实验、细胞侵袭实验评价pGPU6/GFP/Neo GnT-Ⅴ shRNA对人结肠癌LoVo细胞增殖、黏附以及迁移、侵袭能力的影响．实验成功地构建了GnT-Ⅴ shRNA表达质粒,并且该质粒明显下调GnT-Ⅴ的表达,LoVo GnT-Ⅴ/1564和LoVo GnT-Ⅴ/2224的mRNA水平的抑制率分别为82%和71.5%,蛋白质水平的抑制率分别为68%和56%．选择干扰效率较高的LoVo GnT-Ⅴ/1564进行进一步实验．CCK-8增殖实验显示,与阴性对照组相比,LoVo GnT-Ⅴ/1564的增殖受到明显抑制(P < 0.001),尤以72 h为著;下调GnT-Ⅴ表达可增强LoVo细胞的黏附能力( t = -3.357,P < 0.01),而显著抑制LoVo细胞的趋化运动能力( t = 44.051,P < 0.001);划痕实验结果也显示抑制GnT-Ⅴ表达延长LoVo细胞的愈合时间;用Matrigel胶介导的细胞侵袭实验结果显示,LoVo GnT-Ⅴ/1564和LoVo GnT-Ⅴ/NC的穿膜细胞数分别为(5.10 ± 1.25)个和(39.55 ± 2.16)个,GnT-Ⅴ/1564组较阴性对照组明显减少( t = 61.626,P < 0.001)．结果表明,靶向GnT-Ⅴ的shRNA真核表达质粒可以显著降低GnT-Ⅴ的表达,从而抑制LoVo细胞的增殖、迁移和侵袭能力,因此,该GnT-Ⅴ的siRNA序列可能成为治疗结直肠癌的有效靶点．     

TGF-β信号通路抑制剂LY364947对急性髓系白血病细胞增殖、凋亡和侵袭的影响

该文旨在探讨抑制TGF-β信号通路对人急性髓系白血病(acute myeloid leukemia,AML)细胞体外增殖、凋亡和侵袭能力的影响。使用不同浓度TGF-β信号通路抑制剂LY364947处理AML细胞系(KG1a、OCI-AML3)后,采用CCK-8实验检测细胞体外增殖能力;流式细胞术检测细胞周期分布及凋亡情况; Western blot检测细胞周期调控因子Cyclin D1/p21、凋亡相关蛋白Bcl-2/Bax以及上皮细胞间质转化相关蛋白E-cadherin、N-cadherin和vimentin的表达; Transwell实验测定AML细胞迁移及侵袭能力的变化。结果显示:LY364947作用后,白血病细胞生长明显受抑制;细胞周期阻滞在G1期,伴有Cyclin D1表达下调和p21表达上调;细胞凋亡率增加,同时细胞抗凋亡蛋白Bcl-2的表达水平下降,促凋亡蛋白Bax表达增高;细胞体外迁移和侵袭能力减弱。此外, E-cadherin表达增高, N-cadherin和vimentin表达下降。该研究结果提示,抑制TGF-β信号通路能够抑制白血病细胞的体外增殖,诱导细胞凋亡,降低细胞迁移及侵袭能力。     

慢病毒介导的稳定表达LBH的前列腺癌细胞株的建立

目的:构建稳定表达LBH基因的人前列腺癌细胞株PC-3M-LBH,探讨LBH基因对PC-3M细胞增殖能力的影响。方法:构建表达LBH基因的重组慢病毒载体并制备出相应的慢病毒,感染低表达LBH基因的人前列腺癌PC-3M细胞后,经嘌呤霉素筛选获得细胞克隆;实时荧光定量PCR和蛋白印迹法(Western-Blot)分别检测细胞株中LBH的mRNA、蛋白表达水平;采用CCK-8法检测表达LBH基因后细胞增殖能力的改变。结果:成功构建了重组慢病毒表达质粒p Lenti-LBH并包装出了慢病毒,感染前列腺癌细胞后经嘌呤霉素筛选得到PC-3M-LBH细胞株;PC-3M-LBH细胞株中LBH基因的mRNA和蛋白表达显著上调;相对母细胞和NC对照组,PC-3M-LBH细胞在接种后第4天即出现明显的生长抑制,到第6天其生长抑制率达到19.7%。结论:构建的细胞株能稳定表达LBH基因,该基因的表达能显著抑制前列腺癌PC-3M细胞的体外增殖。     

CDADC1在人视网膜色素上皮细胞中功能研究

目的：研究细胞增殖相关基因CDADC1在人视网膜色素上皮细胞ARPE19中的表达及对ARPE19细胞增殖的影响。方法：采用基因重组技术构建荧光表达载体pEGFP－C1－CDADC1和真核表达载体pcDNA3．1-myc-CDADC1,用脂质体转染法转染ARPE19细胞,观察GFP—CDADC1融合蛋白在ARPE19细胞的表达定位,流式细胞仪测定CDADC1转染后对ARPE19细胞生长周期、凋亡的影响。结果：FP—CDADC1融合蛋白亚细胞定位显示,CDADC1低表达于ARPE19细胞胞浆,高表达于细胞核;pcD—NA3．1-myc-CDADC1瞬时转染ARPE19细胞显示24小时细胞无明显改变,48小时后重组质粒转染组S期细胞占细胞总数的19．37％,pcDNA3．1-myc空载质粒转染组S期细胞占10．87％,而空白对照组S期细胞占3．33％,重组质粒转染组与两对照组之间的差异有统计学意义（P〈0．01）。结论：CDADC1在增生性玻璃体视网膜病变（PVR）发生和发展过程中可促进DNA的合成,引起细胞增生。     

LRP16影响宫颈癌Siha细胞对化疗药物的敏感性

目的:探讨抑制LRP16的表达对宫颈癌Siha细胞的化疗药物敏感性的影响。方法:将抑制LRP16表达的小干扰RNA:negativecontrol-si RNA(NC)、si RNA-374(si374)转染入Siha宫颈鳞癌细胞系中,通过顺铂(DDP)和紫杉醇(TAX)的处理后,采用CCK-8检测不同浓度紫杉醇、顺铂作用宫颈癌细胞系Siha48 h后,计算出细胞被抑制一半时顺铂、紫杉醇的药物浓度(IC50);使用Hoechst33342染色观察细胞凋亡,采用流式细胞仪检测顺铂IC50作用Siha细胞48小时后的细胞凋亡情况,紫杉醇IC50作用Siha细胞之后的细胞周期分布情况。结果:CCK-8检测转染的Siha细胞增殖活性受到抑制,Hoechst33342染色观察转染的Siha细胞凋亡明显增加,流式细胞仪检测凋亡显示,si374+顺铂的早期凋亡率22.15±2.24,NC+顺铂12.45±2.72,流式细胞仪检测周期显示G2/M(%),si374+紫杉醇29.94±1.87,NC+紫杉醇17.66±2.32。结论:LRP16基因表达下调之后,抑制Siha细胞的增殖、促进其凋亡,使细胞周期滞留于G2/M期,从而提高Siha细胞的化疗敏感性。     

miR-184通过抑制EPB41L5调控大鼠肾癌细胞增殖及迁移

为了探讨miR-184对肾癌细胞的影响及机制,本研究选取肾癌细胞株786-0细胞,随机分为对照组、空白转染组和miR-184转染组,其中miR-184转染组转染miR-184 mimic,空白转染组转染空白mimic,采用CCK-8细胞增殖实验检测各组细胞增殖,流式细胞仪检测各组细胞凋亡,划痕实验检测各组细胞迁移,Western blotting检测各组EPB41L5蛋白表达。研究结果表明miR-184转染组培养48 h和培养72 h时OD值分别为(0.964±0.103)和(1.011±0.121),明显低于对照组和空白转染组(p<0.05);miR-184转染组培养72 h后细胞凋亡率为(18.22±2.26)%,明显高于对照组和空白转染组(p<0.05);miR-184转染组培养24 h后细胞迁移数为(17.21±3.06)个,明显低于对照组和空白转染组(p<0.05);miR-184转染组细胞EPB41L5蛋白相对表达量为(0.241±0.061),明显低于对照组和空白转染组(p<0.05)。本研究初步表明:miR-184可抑制肾癌786-0细胞增殖和迁移,促进细胞凋亡,其可能与其抑制EPB41L5蛋白表达有关。     

AIBP基因表达下调促进心肌微血管内皮细胞血管新生

目的:探讨阻断载脂蛋白A-I结合蛋白(AIBP)的表达后对心肌微血管内皮细胞(CMECs)血管新生的作用。方法:消化法分离SD大鼠CMECs,通过慢病毒介导的siRNA转染CMECs下调AIBP基因表达,并设立空白对照组及阴性转染组。RT-PCR法检测AIBP基因的表达;CCK-8比色法检测细胞增殖;Transwell小室评价细胞迁移能力;成管实验评价血管新生能力。结果:RT-PCR结果显示,与空白对照组及阴性转染组相比,转染组CMECs中AIBP表达显著降低(P0.01);CCK-8结果显示,与空白对照组及阴性转染组相比,转染组CMECs增值水平显著增高(P0.01);Transwell法结果显示,与空白对照组及阴性转染组相比,转染组CMECs迁移能力显著增高(P0.01);成管实验显示,与空白对照组及阴性转染组相比,转染组CMECs成管能力显著增高(P0.01)。结论:抑制AIBP表达可以明显促进CMECs增殖,促进其迁移和成管。     

The effect of gamma-tocopherol on proliferation, integrin expression, adhesion, and migration of human glioma cells

The effect of vitamin E on proliferation, integrin expression, adhesion, and migration in human glioma cells has been studied. gamma-tocopherol at 50 microM concentration exerted more inhibitory effect than alpha-tocopherol at the same concentration on glioma cell proliferation. Integrin alpha5 and beta1 protein levels were increased upon both alpha- and gamma-tocopherol treatments. In parallel, an increase in the alpha5beta1 heterodimer cell surface expression was observed. The tocopherols inhibited glioma cell-binding to fibronectin where gamma-tocopherol treatment induced glioma cell migration. Taken together, the data reported here are consistent with the notion that the inhibition of glioma cell proliferation induced by tocopherols may be mediated, at least in part, by an increase in integrin alpha5 and beta1 expression. Cell adhesion is also negatively affected by tocopherols, despite a small increase in the surface appearance of the alpha5beta1 heterodimer. Cell migration is stimulated by gamma-tocopherol. It is concluded that alpha5 and beta1 integrin expression and surface appearance are not sufficient to explain all the observations and that other integrins or in general other factors may be associated with these events.     

慢病毒载体介导RAB27A基因过表达对人HepG2肝癌细胞增殖的影响

目的：构建RAB27A基因慢病毒表达载体,并研究RAB27A 对人HepG2肝癌细胞增殖能力的影响。方法：以pEGFP-C1-RAB27A质粒为模板,PCR扩增出融合绿色荧光蛋白的RAB27A基因全长,酶切后插入穿梭载体pENTR/U6,再应用Gateway技术,基因重组到表达载体pHAGE-EF1α-puro-DEST上,构建得到重组慢病毒表达载体pHAGE-GFP-RAB27A-puro。测序鉴定序列正确后,将其与包装质粒psPAX2和包膜质粒pMD2.G共转HEK-293T细胞进行慢病毒包装。收集并浓缩培养上清以获得慢病毒颗粒感染HepG2细胞。荧光显微镜下观察HEK-293T细胞和慢病毒感染HepG2细胞绿色荧光强度;Western blot检测稳定感染HepG2细胞株RAB27A 蛋白表达水平;CCK8和平皿克隆形成实验检测稳定过表达RAB27A的HepG2细胞增殖活力的变化;流式细胞术检测稳定过表达RAB27A的HepG2细胞周期分布情况。结果：经双酶切及测序结果证实重组慢病毒表达载体构建正确;浓缩后病毒滴度较高;重组慢病毒感染HepG2细胞后,细胞外源RAB27A的蛋白表达水平显著上调,HepG2细胞的增殖活力和克隆形成能力受到明显抑制（P<0.01）,S期细胞分布比例明显降低（P<0.01）。结论： RAB27A 基因重组慢病毒表达载体构建成功,外源过表达RAB27A 基因可显著抑制HepG2细胞增殖能力。RAB27A在肝细胞癌发生发展和迁移中扮演了重要角色。     

Differential role of beta(1C) and beta(1A) integrin cytoplasmic variants in modulating focal adhesion kinase, protein kinase B/AKT, and Ras/Mitogen-activated protein kinase pathways

The integrin cytoplasmic domain modulates cell proliferation, adhesion, migration, and intracellular signaling. The beta(1) integrin subunits, beta(1C) and beta(1A), that contain variant cytoplasmic domains differentially affect cell proliferation; beta(1C) inhibits proliferation, whereas beta(1A) promotes it. We investigated the ability of beta(1C) and beta(1A) to modulate integrin-mediated signaling events that affect cell proliferation and survival in Chinese hamster ovary stable cell lines expressing either human beta(1C) or human beta(1A). The different cytodomains of either beta(1C) or beta(1A) did not affect either association with the endogenous alpha(2), alpha(V), and alpha(5) subunits or cell adhesion to fibronectin or TS2/16, a mAb to human beta(1). Upon engagement of endogenous and exogenous integrins by fibronectin, cells expressing beta(1C) showed significantly inhibited extracellular signal-regulated kinase (ERK) 2 activation compared with beta(1A) stable cell lines. In contrast, focal adhesion kinase phosphorylation and Protein Kinase B/AKT activity were not affected. Selective engagement of the exogenously expressed beta(1C) by TS2/16 led to stimulation of Protein Kinase B/AKT phosphorylation but not of ERK2 activation; in contrast, beta(1A) engagement induced activation of both proteins. We show that Ras activation was strongly reduced in beta(1C) stable cell lines in response to fibronectin adhesion and that expression of constitutively active Ras, Ras 61 (L), rescued beta(1C)-mediated down-regulation of ERK2 activation. Inhibition of cell proliferation in beta(1C) stable cell lines was attributable to an inhibitory effect of beta(1C) on the Ras/MAP kinase pathway because expression of activated MAPK kinase rescued beta(1C) antiproliferative effect. These findings show that the beta(1C) variant, by means of a unique signaling mechanism, selectively inhibits the MAP kinase pathway by preventing Ras activation without affecting either survival signals stimulated by integrins or cellular interactions with the extracellular matrix. These findings highlight a role for beta(1)-specific cytodomain sequences in maintaining an intracellular balance of proliferation and survival signals.     

Ontogeny of pituitary cell-types and the hypothalamo-hypophysial relationship during early development of chum salmon,Oncorhynchus keta

Tissue non-specific alkaline phosphatase is a membrane-bound glycoprotein enzyme which is characterized by its phosphohydrolytic, protein phosphatase, and phosphotransferase activities. This enzyme is distributed virtually in all mammalian tissues, particularly during embryonic development. Its expression is stagespecific and can be demonstrated in the developing embryo as early as the 2-cell stage. It has been suggested that tissue non-specific alkaline phosphatase might play a role in tissue formation. In the study reported here, a genetransfer approach was employed to investigate possible roles for this enzyme by inserting the cDNA for rat tissue non-specific alkaline phosphatase into CHO and LLC-PK1 cells. Permanently transfected cell-lines expressing varying levels of alkaline phosphatase were estblished. The data showed that functional enzyme was expressed in the transfected cells. Cell spreading and attachment were enhanced in transfected CHO cells expressing high levels of tissue non-specific alkaline phosphatase but not in the LLC-PK1 cells. Further, in CHO cells, proliferation was shown to be inversely proportional to the level of the tissue non-specific alkaline phosphatase expression. Homotypic cell association was demonstrated in both alkaline phosphatase-positive and alkaline phosphatase-negative cells in both CHO and LLC-PK1 celllines. Taken together, these findings suggest that in addition to a role in mineralization of bone, tissue nonspecific alkaline phosphatase might also play a role in other cell activities, including those related to differentiation, such as cell-cell or cell-substrate interaction and proliferation.     

CXCR4 receptor expression on human retinal pigment epithelial cells from the blood-retina barrier leads to chemokine secretion and migration in response to stromal cell-derived factor 1 alpha

Retinal pigment epithelial (RPE) cells form part of the blood-retina barrier and have recently been shown to produce various chemokines in response to proinflammatory cytokines. As the scope of chemokine action has been shown to extend beyond the regulation of leukocyte migration, we have investigated the expression of chemokine receptors on RPE cells to determine whether they could be a target for chemokine signaling. RT-PCR analysis indicated that the predominant receptor expressed on RPE cells was CXCR4. The level of CXCR4 mRNA expression, but not cell surface expression, increased on stimulation with IL-1beta or TNF-alpha. CXCR4 protein could be detected on the surface of 16% of the RPE cells using flow cytometry. Calcium mobilization in response to the CXCR4 ligand stromal cell-derived factor 1alpha (SDF-1alpha) indicated that the CXCR4 receptors were functional. Incubation with SDF-1alpha resulted in secretion of monocyte chemoattractant protein-1, IL-8, and growth-related oncogene alpha. RPE cells also migrated in response to SDF-1alpha. As SDF-1alpha expression by RPE cells was detected constitutively, we postulate that SDF-1-CXCR4 interactions may modulate the affects of chronic inflammation and subretinal neovascularization at the RPE site of the blood-retina barrier.     

FOXO3a过表达对内皮祖细胞周期相关蛋白的调控

目的:观察FOXO3a(forkhead box O3a)的活性改变对内皮祖细胞(endothelial progenitor cells,EPCs)增殖和细胞周期相关蛋白表达的影响。方法:将携带突变激活FOXO3a基因的腺病毒载体Ad-TM(triple mutant)-FOXO3a和阴性对照腺病毒载体Ad-GFP体外感染人脐血来源的EPCs。观察EPCs形态学改变,CCK-8分析转染后EPCs增殖情况,Western blot检测FOXO3a蛋白、细胞周期相关蛋白p27kip1以及CDK2的表达水平。结果:构建了的2种腺病毒相关载体被成功转染。形态学改变方面,Ad-TM-FOXO3a组EPCs细胞生长缓慢,集落不明显;Western blot和CCK-8结果显示,Ad-TM-FOXO3a转染组与阴性对照组相比,EPCs增殖被抑制,FOXO3a与p27kip1蛋白过表达,CDK2表达下调。结论:FOXO3a可能通过上调p27kip1蛋白表达,下调CDK2表达,以抑制EPCs增殖。