人PD-L1真核表达载体的构建及结肠癌细胞稳定表达单克隆株的筛选和鉴定

目的:构建人程序性死亡配体1（PD-L1）重组质粒载体,筛选稳定高表达人PD-L1的结肠癌单克隆细胞株。方法:提取HCT116细胞总RNA,RT-PCR克隆PD-L1基因片段,将其重组至含有HA标签和Neo真核细胞筛选抗性的pcDNA3质粒载体上,转染HCT116细胞,倍比稀释8个细胞浓度至96孔板,G418筛选两周,挑取单细胞克隆,通过免疫印迹鉴定外源性PD-L1的表达;通过MTS、Transwell和软琼脂细胞克隆形成实验比较PD-L1低表达和高表达单克隆细胞株生长增殖、迁移和细胞克隆形成能力的差别;最后通过在两组细胞中过表达帽依赖性荧光素酶报告基因阐述造成上述表型的可能机制。结果:成功构建人PD-L1的真核表达载体,并筛选获得稳定高表达PD-L1的HCT116单克隆细胞株。功能研究初步证明PD-L1可促进细胞克隆形成能力、迁移和生长增殖。过表达PD-L1可使帽依赖性荧光素酶报告基因的表达上调约3~4倍,表明其机制部分为PD-L1可上调帽依赖性蛋白质翻译。结论:获得了PD-L1重组质粒载体及可用于后续功能研究的稳定高表达人PD-L1的HCT116单克隆细胞株。     

PRL-3对结直肠癌细胞迁移、侵袭能力的影响

目的:构建肝再生磷酸酶-3（phosphatase of regenerating liver-3,PRL-3）基因过表达的重组慢病毒载体,研究其对结直肠癌细胞系HCT116迁移、侵袭能力的影响。方法:PCR扩增PRL-3基因并克隆至pcDH载体,构建成pcDH-PRL-3过表达载体,再将其与慢病毒包装载体共转染293T细胞,包装成Lenti-PRL-3重组慢病毒载体,并感染结直肠癌细胞系HCT116。利用qPCR、Western分别从mRNA、蛋白水平检测PRL-3表达情况;通过划痕实验、Transwell实验研究过表达PRL-3对结直肠癌细胞系HCT116侵袭能力的影响。结果:成功构建Lenti-PRL-3重组慢病毒载体,并在结直肠癌细胞系HCT116过表达。划痕实验、Transwell实验结果表明过表达PRL-3能够促进HCT116细胞的迁移、侵袭。结论:构建Lenti-PRL-3重组慢病毒载体,在结直肠癌细胞系HCT116过表达PRL-3后能增加细胞的迁移、侵袭能力。     

MTA1通过上调CK19促进结肠癌细胞HCT116的侵袭

目的探讨肿瘤转移相关因子1(MTA1)与细胞角蛋白19(CK19)在结肠癌中的表达及意义。方法选取80例结肠癌患者的结肠癌组织及癌旁组织标本,采用免疫组织化学法检测组织中MTA1及CK19的表达,分析两者在结肠癌组织中表达的相关性。采用慢病毒感染法、crispr基因编辑技术分别建立MTA1过表达及敲除MTA1的结肠癌HCT116细胞系及对应的对照细胞系(分别命名为HCT116MTA1、HCT116crMTA1、HCT116control 1、HCT116crMTA1control 2),利用RNA干扰技术、质粒转染法分别在HCT116MTA1、HCT116crMTA1细胞中敲降、过表达CK19,并构建对照细胞系(分别命名为HCT116MTA1siCK19、HCT116crMTA1CK19、HCT116MTA1control、HCT116crMTA1control)。通过Transwell侵袭实验检测MTA1、CK19表达的改变对细胞侵袭能力的影响。利用c BioPortal数据分析平台筛选与MTA1和CK19表达均相关的基因,对所获得的基因集进行功能富集分析。结果结肠癌组织中MTA1、CK19评分均明显高于癌旁组织,差异均有统计学意义(P<0.01)。MTA1与CK19在结肠癌组织中表达呈显著正相关(r=0.490,P<0.01);在MTA1过表达的HCT116MTA1细胞中CK19表达上调,而在敲除MTA1的HCT116crMTA1细胞中CK19表达下调。与MTA1和CK19表达均相关的基因富集在细胞黏附、m RNA剪接、细胞代谢、蛋白质合成等过程。结论MTA1与CK19在结肠癌组织中表达呈正相关,MTA1可通过上调CK19表达促进结肠癌细胞HCT116的侵袭。     

成纤维生长因子19稳定敲减对大肠癌细胞增殖、迁移的影响

目的:构建慢病毒稳定敲减FGF19大肠癌细胞系,探究FGF19敲减对人大肠癌细胞增殖、迁移的影响。方法:通过慢病毒转染大肠癌COLO201和HCT116细胞,分别在适宜病毒转染指数条件下转染并构建稳转株;以嘌呤霉素进行筛选,获得稳定敲减FGF19的细胞株;PCR和Western bloting鉴定COLO201和HCT116稳转细胞株中FGF19的表达情况;Transwell实验检测细胞的迁移活性,CCK-8和克隆形成实验检测细胞的增殖活性。结果:成功构建了稳定敲减FGF19的两株大肠癌细胞。稳定敲减FGF19的HCT116、COLO201细胞(KD组)的FGF19 mRNA水平与空载对照组(NC组)相比明显减少(P=0.001 1,P=0.000 1);与NC组相比,KD组细胞的FGF19蛋白表达明显下降,差异均具有统计学意义(P=0.001,P=0.000 1)。KD组细胞的迁移活性以及增殖能力均相比NC组明显下降(迁移P=0.001 7/P=0.000 1; CCK-8 P=0.042 5/P=0.033 4;克隆P=0.005 1/P=0.002 2)。结论:成功构建FGF19...     

抑制DEK基因表达对结肠癌HCT116细胞增殖的影响

目的:通过siRNA技术,阻断结肠癌细胞系HCT116中DEK基因的表达,并研究DEK基因沉默后对HCT116细胞增殖能力影响。方法:用真核转录载体pLKO.1-TRC cloning vector构建针对DEK基因的重组siRNA真核转录载体pLKO.1-siDEK A,pLKO.1-siDEK B和pLKO.1-siDEK C,脂质体法转染结肠癌细胞系HCT116,Western blot检测DEK的表达变化;选择沉默效率最高的载体,采用噻唑蓝(MTT)比色法、克隆形成实验检测转染HCT116细胞在增殖、克隆形成等方面的改变,流式细胞术检测其细胞周期的改变。结果:重组载体pLKO.1-siDEK A有效地阻断了HCT116细胞中DEK基因的表达。pLKO.1-siDEK A转染HCT116细胞后,与对照组相比细胞生长、增殖速度明显减慢(P<0.05),克隆形成率明显下降;流式细胞术表明DEKsiRNA可导致HCT116细胞G0/G1期阻滞,S期细胞减少。结论:成功构建了可有效沉默DEK基因的siRNA干涉载体,证明沉默DEK基因对人结肠癌HCT116细胞增殖有负性调节作用。本研究为进一步阐明DEK基因在结直肠癌中的作用奠定了基础。     

ZIC1过表达对结直肠癌HCT-116细胞增殖及对苦参碱类生物碱药物敏感性的影响

目的:检测ZIC1基因在结直肠癌细胞内过表达后对癌细胞增殖能力的影响,以及对苦参碱类生物碱药物敏感性的改变情况。方法:首先从五种结直肠癌细胞株中筛选出ZIC1基因表达最低的一株,对其进行慢病毒转染,使其稳定表达ZIC1基因或空载体,再利用Western blot技术和qRT-PCR技术鉴定ZIC1蛋白/mRNA表达情况。通过CCK-8法和平板克隆形成实验检测过表达ZIC1基因后细胞增殖能力的改变,并利用CCK-8法分析稳转细胞株对苦参碱类生物碱药物敏感性的改变。结果:HCT116细胞株中ZIC1 mRNA/蛋白表达均显著低于其他四株（P<0.001）;慢病毒转染后,含rLV-ZIC1-PGK-Puro的重组慢病毒转染HCT116细胞内ZIC1 mRNA/蛋白表达水平显著高于对照组（P<0.001）。CCK-8实验结果示,ZIC1基因过表达后HCT116细胞增殖能力明显降低（P<0.01）;实验组克隆形成率明显低于对照组（P=0.003）。CCK-8法发现ZIC1过表达后HCT116结直肠癌细胞对苦参碱及槐定碱的药物敏感性得到明显的升高,而对氧化苦参碱及槐果碱的药物敏感性无明显改变。结论:HCT116结直肠癌细胞内ZIC1基因过表达后能有效抑制癌细胞的增殖,并增敏苦参碱及槐定碱对结直肠癌HCT116细胞的药理作用。     

基于3T3-L1细胞株的人类ADRB1基因稳定过表达模型的构建

目的:构建ADRB1基因稳定过表达的细胞模型。方法:将ADRB1 cDNA克隆片段和慢病毒载体连接;将重组载体与慢病毒包装质粒共转染293T细胞,收集上清液感染3T3-L1前脂肪细胞,利用GFP流式分选法筛选稳转细胞株。结果:Western blot检测证明,ADRB1过表达组的ADRB1蛋白水平显著高于mock组。结论:基于3T3-L1细胞株的ADRB1基因稳定过表达模型构建成功,为研究ADRB1在肿瘤恶病质脂肪消耗中的作用奠定了基础。     

CDK2AP1 基因过表达慢病毒载体的构建与鉴定

目的：构建CDK2AP1基因慢病毒过表达载体,感染人口腔鳞癌细胞系SCC-25细胞系中,为CDK2API基闲体内外实验研究奠定实验基础。方法：将pCDH—CMV—GFP慢病毒载体sall和XbaI酶切位点插入CDK2APl基因序列,构建pCDH—GFP—CDK2API慢病毒质粒。经PCR鉴定、测序验证CDK2API基因后,将其和慢病毒包装质粒混合物共同转染病毒包装细胞293TN,转染24小时后产生藿组病毒GFP—CDK2API慢病毒颗粒。经病毒浓缩纯化后,感染SCC-25口腔鳞痛细胞系并测定感染效率。结果：GFP—CDK2AP1病毒中携有转染正确的CDK2API璀因,感染人SCC-25细胞系后能稳定表达。结论：成功地在舌鳞癌细胞系SCC-25中构建了CDK2APl基因的重组慢病毒过表达载体,为研究其住头颈鳞癌的生物学功能奠定基础。     

γ-synuclein对结肠癌细胞系体外生物学行为影响的观察

目的:构建针对人γ-synuclein基因的shRNA真核表达载体,观察γ-synuclein基因对人结肠癌细胞系体外生物学行为的影响。方法:根据人γ-synuclein序列设计并构建γ-synuclein基因的shRNA真核表达载体,以脂质体转染的方法将γ-synuclein干扰质粒转染至人结肠癌细胞株HCT116,经G418筛选出稳定转染的细胞株。应用CCK8法检测γ-synuclein干扰对HCT116细胞增殖的影响,软琼脂克隆形成实验检测细胞体外克隆形成能力,细胞划痕实验检测细胞体外迁移能力,Transwell小室法检测细胞体外侵袭能力。结果:经测序证明γ-synuclein的shRNA序列已成功插入pGCsi-U6/neo/GFP质粒中,构建的干扰质粒能够显著抑制γ-synuclein mRNA及蛋白的表达。γ-synuclein受抑制后,HCT116细胞增殖数目从48h后开始减少,持续72h,与空质粒组及未转染组相比,差异均有统计学意义,P<0.05。siRNA组细胞克隆形成率为(9.6±2.9)%,显著低于未转染组的(29.4±4.5)%和空质粒组的(32.1±5.8)%,差异均具有统计学意义,P<0.05。在细胞划痕实验中,γ-synuclein被抑制后细胞划痕损伤愈合的速度明显减慢。在侵袭实验中,穿过Matrigel胶及Transwell小室膜的siRNA组侵袭细胞数为20.1±5.26,显著低于未转染组的100和空质粒组的105.4±12.5,差异均有统计学意义,P<0.05。结论:干扰γ-synuclein的表达可显著抑制结肠癌细胞体外增殖、克隆形成和迁移侵袭能力。     

MicroRNA-194过表达与抑制表达慢病毒载体的构建及对骨肉瘤细胞转染与筛选的方法学研究

目的：构建针对人microRNA—194过表达及抑制表达的慢病毒表达载体,寻找与探讨感染人骨肉瘤细胞系SO-SP-9607和U2-os的最佳步骤和方法。方法：利用PcR方法调取相应目的基因进行酶切,经电泳回收后与目的基因进行连接,产物转化细菌感受态细胞,对克隆进行PcR鉴定和测序对比分析后,构建相应microRNA—194过表达及抑制表达慢病毒表达载体;在人骨肉瘤细胞系SO-SP-9607和U2—os转染及筛选过程中,根据不同阶段及浓度设定相应实验组,并设相应对照组。倒置显微镜观察转染效率,筛选情况,进行比较。结果：PCR及测序结果证实重组慢病毒表达质粒构建正确。过表达及抑制表达重组慢病毒的滴度分别为15×10^8TU／ml及4×10^8TU／ml。感染复数（multiply of infection,MOI）值测定,实验组及对照组转染效率无明显差异,获得MOI值及感染时间数据。通过新的综合设计,经筛选后获得转染效率满意的目的克隆细胞。结论：成功构建了microRNA—194过表达及抑制表达慢病毒表达载体,并通过新的综合考虑设计,对人骨肉瘤细胞系SO-SP-9607和U2-os进行转染和筛选后,可较快和较高效率获得满意目的细胞。     

Expression of the antiangiogenic factor 16K hPRL in human HCT116 colon cancer cells inhibits tumor growth in Rag1(-/-) mice

The M(r) 16,000 NH(2)-terminal fragment of human prolactin (16K hPRL) is a potent antiangiogenic factor inhibiting endothelial cell function in vitro and neovascularization in vivo. The present study was undertaken to test the ability of 16K hPRL to inhibit the growth of human HCT116 colon cancer cells transplanted s.c. into Rag1(-/-) mice. For this purpose, HCT116 cells were stably transfected with an expression vector encoding a peptide that included the signal peptide and first 139 amino acid residues of human prolactin (HCT116(16K)). Stable clones of HCT116(16K) cells secreted large amounts of biologically active 16K hPRL into the culture medium. Growth of HCT116(16K) cells in vitro was not different from wild-type HCT116 (HCT116(wt)) or vector-transfected HCT116 (HCT116(vector)) cells. Addition of recombinant 16K hPRL had no effect on the proliferation of HCT116(wt) cells in vitro. Tumor growth of HCT116(16K) cells implanted into Rag1(-/-) mice was inhibited 63% in four separate experiments compared with tumors formed from HCT116(wt) or HCT116(vector) cells. Inhibition of tumor growth of HCT116(16K) cells was correlated with a decrease in microvascular density by 44%. These data demonstrate that biologically active 16K hPRL can be expressed and secreted from human colon cancer cells using a gene transfer approach and that production of 16K hPRL by these cells was capable of inhibiting tumor growth and neovascularization. These findings support the potential of 16K hPRL as a therapeutic agent for the treatment of colorectal cancer.     

NP9基因的克隆及对细胞周期素D1转录活性的影响

背景与目的：NP9基因是我们在鼻咽癌中克隆到的一个新的表达下调的基因(GenBank登录号：BF718797),为了进一步研究该基因的功能,我们构建了人NP9基因编码区序列的真核表达质粒,并研究其表达对细胞周期素D1(cyclinD D1)的影响。方法：通过核苷酸同源序列比较(BlastN)得到NP9 EST的同源cDNA,RT-PCR扩增其编码区序列并构建真核表达重组质粒pRe／CMV2-NP9,脂质体转染后G418筛选出稳定、高效转录NP9基因的细胞克隆;再通过脂质体转染cyclinD D1 promoter Luc和NF-kB—Luc质粒到稳定表达NP9基因的细胞克隆,测定荧光素酶的活性以确定NP9基因对cyclinD D1和NF-kB转录活性的影响;同时亚克隆：NP9基因编码序列到载体pEGFP—C1中,脂质体转染细胞以确定NP9蛋白在细胞中的定位。结果：融合的绿色荧光蛋白出现于细胞核。G418抗性克隆中,RT-PCR扩增证实部分克隆表达NP9基因,且强弱不同。表达NP9基因的细胞克隆在瞬间转染cyclinD D1 promoter Luc和NF-kB-Luc 48h后,荧光素酶的活性较其对照组分别下降46％和63％。结论：NP9蛋白在细胞核内表达;NP9基因通过抑制核转录因子NF-kB的转录活性下调cyclinD D1的表达。     

Questioning the oncogenic role of DeltaNp73alpha in different cell lines expressing p53 or not

The recent finding that the 1p36.3 locus gene encodes an array of different p73 isoforms with apparently distinct and sometimes opposing cellular functions, might explain the difficulty in establishing the protein's role as tumor suppressor. Therefore we need to investigate the roles of each of these splicing variants in cellular functions when expressed alone or in combination with other family members, as well as the genetic background on which the proteins are expressed. We investigated, in two p53 null cell lines, the human SCLC line H1299 and a subline derived from the human colon carcinoma cell line HCT116 (HCT116/379.2), the effects of DeltaNp73alpha overexpression on cell growth and the response to anticancer treatment. We generated three different clones overexpressing DeltaNp73alpha under a tetracycline inducible promoter. Immunofluorescent staining and luciferase reporter assays confirmed that clones HCT116/DeltaNA and H1299/DeltaN7 and H1299/DeltaN11 did express a functional, nuclear localized DeltaNp73alpha protein. The stable overexpression of DeltaNp73alpha protein did not confer any cell growth advantage. Doubling time of clones overexpressing DeltaNp73alpha were comparable to counterparts not expressing it. Clonogenic assays showed that the cytotoxic activity of different DNA damaging agents, such as cDDP, UV light and doxorubicin, were comparable in clones expressing DeltaNp73 or not. The overall data argue against an oncogenic role for this isoform. These findings are independent of the p53 status since they overlap with those previously obtained by our group in HCT116 cell lines, wild type for p53.     

miRNA-34 a对人结肠癌细胞 HCT116增殖及侵袭转移的影响

目的：研究微小RNA-34a（microRNA-34a,miR-34a）在人结肠癌细胞株HCT116中的过表达对细胞增殖和侵袭的影响及其机制。方法设计合成并构建携带绿色荧光蛋白（ GFP）的miR-34a真核表达载体,脂质体法稳定转染HCT116细胞。通过Realtime PCR验证转染后miR-34a的表达变化。 MTT法检测转染前后HCT116细胞增殖能力变化, Transwell法检测转染前后HCT116细胞侵袭能力改变,western blot检测目的蛋白的表达。结果 miR-34a转染HCT116细胞后其表达量增加到（7．32±1．34）倍,而HCT116细胞增殖能力也受到显著抑制,下降到（0．49±0．10）;Bcl-2蛋白受到miR-34a表达的抑制,而BAX的表达则受到miR-34a表达的增强;HCT116细胞侵袭能力在miR-34a过表达后显著增强,相应的MMP-2和MMP-9表达也出现显著增强。阴性对照组与空白对照组比较无显著性差异。结论 miR-34a的过表达能够抑制人结肠癌细胞HCT116的增殖及侵袭转移,与调控Bcl-2／BAX和MMP-2和-9蛋白的表达密切相关。     

Hypoxia-induced enrichment and mutagenesis of cells that have lost DNA mismatch repair

Loss of DNA mismatch repair (MMR) increases the risk of spontaneous mutations. We sought to determine whether there was an interaction between hypoxia and MMR deficiency that might contribute to the phenomenon of tumor progression. Human colon carcinoma HCT116+ch2 (MMR-deficient) and HCT116+ch3 (MMR-proficient) sublines were exposed for varying periods of time to an environment of <0.1% O2 and pH as low as 6.1. When a population containing 5% MMR-deficient cells and 95% MMR-proficient cells was subjected to hypoxia for 72 h, the MMR-deficient cells were enriched by a factor of 2-fold in the surviving population, whereas no enrichment was detected in cells maintained under aerobic conditions. The potential of hypoxia to destabilize the genome was determined by measuring the frequency of clones in the surviving population resistant to very high concentrations of 6-thioguanine or cisplatin. A 72-h exposure to hypoxia did not increase the frequency of resistant clones in the MMR-proficient cells but produced a 7.8-fold increase in 6-thioguanine-resistant clones and a 2.5-fold increase in cisplatin-resistant clones in the MMR-deficient cells. Loss of MMR increased the frequency of mutations in a reporter vector sensitive to frameshift mutations in a microsatellite sequence. Exposure to hypoxia for a time period as short as 48 h further increased the number of mutations in both cell types, but the absolute number of mutants was higher in the MMR-deficient cells. These results indicate that hypoxia and its accompanying low pH enrich for MMR-deficient cells and that loss of MMR renders human colon carcinoma cells hypersensitive to the ability of hypoxia to induce microsatellite instability and generate highly drug-resistant clones in the surviving population.     

利用GFP逆转录病毒标记肿瘤与血管内皮细胞

目的 制备携带GFP基因的逆转录病毒,以简便、快速标记活细胞。方法 将编码GFP的cDNA片段插入逆转录病毒载体pLNCX构建重组逆转录病毒载体pLNCX-GFP,借助脂质体转染单嗜性及双嗜性逆转录病毒包装细胞,G418筛选抗性克隆,然后利用荧光显微镜选出GFP表达最高的克隆。取含有毒颗粒的上清液感染NIH3T3及多种肿瘤或血管内皮细胞。结果 重组逆转录病毒载体pLNCX-GFP转染包装细胞后,包装细胞可表达GFP并产生GFP逆转录病毒。尽管GFP逆转录病毒对动物及人的肿瘤细胞或血管内皮细胞的感染能力各不相同,但由于逆转录病毒能整合进入宿主细胞基因组DNA内,经短期G418筛选后容易获得持续、稳定、高水平表达GFP的阳性细胞。表达GFP的肿瘤细胞仍可在同系动物体内生长并持续表达GFP。携带GFP基因的逆转录病毒能简便、快速介导稳定的基因转移,遗传标记多种细胞,比表达质粒等更优越。     

Cellular response and activation of apoptosis by mithramycin SK in p21-deficient HCT116 human colon carcinoma cells

HCT116 (p21^−/−) human colon carcinoma cells treated with mithramycin SK (MSK), a novel analog of the antitumor antibiotic mithramycin A (MTA), were transiently arrested in G2/M, with some cells entering a faulty mitotic cycle without cytokinesis that resulted in G1-like cell arrest, which consisted of post-mitotic aneuploid G1 cells. Some of these cells synthesized DNA and elicited an apoptotic response. The absence of p21^WAF1 made HCT116 cells more sensitive to MSK than to the related MTA. MSK also showed higher antiproliferative activity than MTA on HCT116 cells with different genetic backgrounds, including those lacking the p53 gene. Apoptosis in MSK-treated p21^−/− cells involved caspase 2 rather than caspase 3. Untreated HCT116 (p21^−/−) cells presented a little caspase 3 activity, which increased slightly after treatment with MSK. The apoptotic response in p21^−/− cells comprised caspase 2 acting as an executor caspase together with a loss of mitochondrial membrane potential that may be initiated by caspase 2. In contrast, caspase 3 was activated in wild-type HCT116 after treatment with MSK.     

MTA1基因表达与人骨肉瘤细胞浸润和转移的关系

Objective： To compare the expression level of metastasis associated-1 （MTA1） in the higher and lower metastasis sublines of human osteosarcoma cells （MG63）, and to investigate the relationship between the expression level of MTA1-EGFP and in vitro invasion and metastasis of human osteosarcoma cells. Methods： The expression level of MTA1 in two sublines of MG63 cells was detected by semi-quantitative RT-PCR, and cell invasion assay and cell proliferation assay were used to evaluate the invasive capacity in vitro in two sublines. The lower metastasis line of MG-63 cells were transfected with MTA1-EGFP full-length cDNA expression plasmid by lipofectamine. The changes of the MTA1-EGFP expression and in vitro invasion potential were measured after transfection. Results： M8 subline expressed significantly higher level of MTA1 than that of M6 subline by RT-PCR. The invasive potentials of low metastasis MG63 cell line were increased after MTA1 gene transfection. Conclusion： There may be a relationship between MTA1 and invasive potentials of human osteosarcoma cells, and MTA1 may play a role in the molecular mechanism of tumor metastases and be a potential target for gene therapy of osteosarcoma. Further studies of MTA1 in human ostersarcoma cell metastasis are needed.