抑癌候选基因NDRG2 对结肠癌细胞SW620 的迁移和侵袭力的影响

目的:观察NDRG2对结肠癌SW620细胞侵袭、转移等生物学行为的影响,探讨其可能的调节机制。方法:用阳离子脂质体转染方法分别转染pcDNA3.1-Ndrg2和SiRNA-Ndrg2于SW620细胞内48h,上调/下调NDRG2的表达;检测NDRG2基因mRNA及蛋白表达水平的变化;通过划痕试验及transwell细胞侵袭试验进一步对上调/下调NDRG2表达水平后的结肠癌细胞迁移和侵袭能力进行分析。结果:pcDNA3.1-Ndrg2转染SW620后,NDRG2的mRNA和蛋白表达水平明显升高,细胞的迁移和侵袭能力下降;SiRNA-Ndrg2转染SW620后,NDRG2的mRNA和蛋白表达水平明显降低,细胞的迁移和侵袭能力上升,差异具有统计学意义(P<0.05)。结论:NDRG2作为抑癌候选基因能够降低结肠癌细胞转移和侵袭能力。     

抑癌候选基因NDRG2对结肠癌细胞SW620的迁移和侵袭力的影响

目的：观察NDRG2对结肠癌SW620细胞侵袭、转移等生物学行为的影响,探讨其可能的调节机制。方法：用阳离子脂质体转染方法分别转染pcDNA3.1-Ndrg2和SiRNA-Ndrg2于SW620细胞内48h,上调/下调NDRG2的表达;检测NDRG2基因mRNA及蛋白表达水平的变化;通过划痕试验及transwell细胞侵袭试验进一步对上调/下调NDRG2表达水平后的结肠癌细胞迁移和侵袭能力进行分析。结果：pcDNA3.1-Ndrg2转染SW620后,NDRG2的mRNA和蛋白表达水平明显升高,细胞的迁移和侵袭能力下降;SiRNA-Ndrg2转染SW620后,NDRG2的mRNA和蛋白表达水平明显降低,细胞的迁移和侵袭能力上升,差异具有统计学意义（P〈0.05）。结论：NDRG2作为抑癌候选基因能够降低结肠癌细胞转移和侵袭能力。     

基于生物信息学的抑癌基因NDRG2相互作用蛋白预测及验证

NDRG2(N Myc downstream regulator gene 2)是NDRG 家族成员之一. 以往研究表明,该家族与细胞的增殖和分化有关. 而该分子参与的细胞信号通路及调节机制尚未阐明. 本研究利用保守蛋白间相互作用（interologs）的生物信息学方法预测NDRG2相互作用分子,并通过免疫共沉淀（Co-IP）及His pull-down蛋白体外结合实验方法对预测结果进行验证. 生物信息学软件预测和分析结果表明,细胞中存在多个可能与NDRG2发生相互作用分子.结合文献报道,从中选取了3个候选分子Gnb1、 Rgs16及 Rgs5进行分子生物学实验验证.Co-IP及His pull-down实验结果表明,3个候选分子中,Rgs5蛋白能够和NDRG2蛋白相互作用,而其它2个候选分子与NDRG2的相互作用未获得实验室方法的验证.研究结果表明,生物信息学分析与实验室验证相结合是一种高效省时的蛋白质相互作用研究策略.通过这种策略证实NDRG2可以与 Rgs5蛋白相互作用,为后续NDRG2功能的研究提供了有效的线索.     

抑癌候选基因NDRG2在甲状腺癌组织中的表达及其意义

目的:研究抑癌候选基因NDRG2在人类甲状腺癌组织及其癌旁组织中的表达情况.方法:收集30例甲状腺癌组织及其癌旁组织,提取总RNA,应用半定量RT-PCR方法检测NDRG2 mRNA的表达水平.分别提取30例组织的总蛋白,应用蛋白印迹技术检测其NDRG2的蛋白表达水平.结果:RT-PCR结果显示,30例甲状腺癌组织中,有25例NDRG2的mRNA水平明显降低,蛋白印迹结果显示,30例甲状腺癌组织中发现25例NDRG2的蛋白水平明显下降,与RT-PCR检测结果一致.结论:NDRG2在甲状腺癌组织中呈低表达,提示其可能对甲状腺癌的发生或发展有重要作用影响.     

应用组织芯片技术研究抑癌候选基因NDRG2在淋巴瘤组织中的表达及其意义

目的:应用组织芯片技术分析抑癌候选基因NDRG2在人类淋巴瘤组织、淋巴结正常组织及淋巴结良性病变组织中的表达情况.方法:采用小鼠抗NDRG2单克隆抗体的免疫组织化学ABC法,研究NDRG2在不同淋巴结组织的表达,并分析NDRG2在不同淋巴结组织中的表达差异.结果:免疫组化结果显示,淋巴瘤组织与淋巴结良性病变组织中DNRG2的表达相比呈显著性差异(P<0.05),淋巴瘤组织与正常淋巴结组织中DNRG2的表达相比呈显著性差异(P<0.05).淋巴结良性病变组织与正常淋巴结组织中DNRG2的表达相比呈显著性差异(P<0.05).正常淋巴结,淋巴结良性病变及淋巴瘤组织中NDRG2的阳性表达率分别为92.5%(37/40)、67.5%(27/40)和18.51%(15/81),3者间比较,差异有统计学意义.结论:NDRG2在淋巴瘤组织中呈低表达,提示其可能对淋巴瘤的发生或发展有重要作用,这不仅为研究淋巴瘤的发病机制进一步提供了线索,而且对淋巴瘤的诊断和治疗具有重要意义.     

敲除NDRG2 基因的AD模型小鼠的构建与鉴定

目的:构建与鉴定NDRG2基因全身敲除的阿尔茨海默症(AD)小鼠模型。方法:将NDRG2-/-、APP/PS1进行饲养杂交繁殖,将通过PCR技术鉴定基因型为NDRG2+/-APP/PS1的子一代小鼠再与NDRG2-/-小鼠回交获得子二代小鼠,提取子二代小鼠的基因组DNA再利用PCR方法:扩增NDRG2和APP/PS1基因片段并进行琼脂糖凝胶电泳检测获得4种基因型的小鼠。结果:选取基因型为NDRG2-/-APP/PS1的小鼠即为全身NDRG2敲除且淀粉样蛋白基因过表达的阿尔茨海默症模型小鼠。应用PCR方法:鉴定NDRG2基因全身敲除的AD小鼠模型。成功获得NDRG2基因全身敲除的AD小鼠,该基因型小鼠有繁殖能力,其繁殖符合孟德尔遗传规律。结论:成功构建NDRG2基因敲除的阿尔茨海默症模型小鼠,为进一步研究NDRG2基因在阿尔茨海默症病理发展过程中的作用机制及新的治疗方法的研究提供模型基础。     

NDRG2在人胚胎组织中的表达分布特点

本文旨在研究NDRG2在不同胎龄人胚胎组织中的表达水平及细胞定位。利用RT-PCR和Western blot研究NDRG2 mRNA和蛋白在胎心、肺、肝和肾中的表达水平,免疫组织化学分析NDRG2蛋白在多种胚胎组织中的分布特点。结果表明,NDRG2在胚胎组织中的表达随胚龄的延长而增加。NDRG2 mRNA和蛋白在胎心和肺中的变化一致;在胎肝中mRNA表达低而蛋白表达高,在胎肾中则相反。NDRG2蛋白阳性反应产物存在于细胞胞浆,见于小肠绒毛上皮细胞、结肠上皮细胞、皮肤表层细胞及毛囊、肺内小气道内衬上皮细胞、肝细胞、心肌细胞、胸腺小体、肾小管上皮细胞。结果提示,NDRG2蛋白可能不是一个组织特异性蛋白,并在组织和器官的形成中起作用。     

抑制NDRG2基因表达对宫颈癌Hela细胞紫杉醇化疗敏感性的影响

目的:NDRG2是N-Myc downstream regulated gene家族的成员之一,与细胞增殖和分化相关.前期研究发现,抑制NDRG2表达可以提高宫颈癌Hela细胞对于顺铂的化疗敏感性,本研究采用RNA干扰技术抑制人宫颈癌Hela细胞中NDRG2基因的表达研究其对Hela细胞紫杉醇化疗敏感性的影响.方法:利用化学合成的针对NDRG2特异性siRNA瞬时转染Hela细胞株,采用RT-PCR和Western Blot检测NDRG2 mRNA和蛋白表达情况,通过MTT法检测其与对照细胞在顺铂作用下的体外存活率差异.SPSSll.0统计包处理,采用t检验,P＜0.05为差异有统计学意义.结果:在mRNA和蛋白水平,化学合成的NDRG2特异性siRNA oligomer可使Hela细胞的NDRG2表达水平明显降低.在0.1、1、10、100、500、1000 μg/mL紫杉醇浓度组,Negative-control和NDRG2siRNA细胞的相应细胞存活率分别为97.21±2.38、90.09±2.42、83.35±3.86、62.93±3.75、18.22±5.46、1.14± 0.67和99.62±3.15、94.91±3.83、85.71±2.93、58.59± 3.36、17.99±3.40、0.73±0.34,组间比较P值均大于0.05,差异无统计学意义.结论:抑制NDRG2表达不影响宫颈癌Hela细胞在紫杉醇作用下的细胞存活率,不能提高其对紫杉醇的化疗敏感性.进一步拓展了对该基因的功能认知.     

NDRG2调控大鼠肝细胞周期的机制

目的:阐明NDRG2(N-Myc downstream-regulated gene2)在大鼠肝再生过程中时肝细胞周期的调控机制.方法:大鼠70%肝切除后收集0 h、8 h、24 h、48 h、72 h、7 d、10 d的再生肝组织,采用Real-time PCR和Western blot方法检测大鼠肝再生过程中NDRG2基因和蛋白的动态变化.流式细胞仪检测腺病毒介导的高表达NDRG2对大鼠正常肝细胞系(BRL)细胞周期的影响.Real.time PCR和Western blot方法检测高表达NDRG2对肝细胞周期调控的分子机制.结果:NDRG2基因和蛋白的表达水平在肝再生达到高峰时明显下降,在肝细胞进入分化期时显著上调;流式细胞仪检测显示BRL细胞中高表达NDRG2 48 h后,G0/G1期细胞百分比从对照组39.30+1.97上升至57.44±2.56,S期从37.66±1.73下降至13.27±2.01,差异有统计学意义(P＜0.05).对周期调控相关分子的检测显示高表达NDRG2对肝细胞周期的影响是通过上调p21,抑制Cyclin E实现的.结论:NDRG2通过影响细胞周期参与调控大鼠肝再生过程.     

Adenovirus-Mediated NDRG2 Inhibits the Proliferation of Human Renal Cell Carcinoma Cell Line OS-RC-2 in Vitro

The objective of the study is to investigate the inhibitory effects of adenovirus-mediated N-Myc downstream-regulated gene 2 (NDRG2) on the proliferation of human renal cell carcinoma cell line OS-RC-2 in vitro. NDRG2 was harvested by RT-PCR, confirmed by DNA sequencing, and then cloned into the eukaryotic expression vector pIRES2-EGFP, which encodes green fluorescent protein (GFP), to construct pIRES2-EGFP-NDRG2 plasmid. OS-RC-2 cells with NDRG2 negative expression were transfected with pIRES2-EGFP-NDRG2 plasmid. The growth of transfected OS-RC-2 cells was observed under the light and fluorescence microscopes. After colony-forming cell assays, cell proliferation detection, and MTT assays, the growth curves of cells in each group were plotted to investigate the inhibitory effects of adenovirus-mediated NDRG2 on the proliferation of OS-RC-2 cells. Cell cycle was determined by flow cytometry. Confocal laser scanning microscopy was applied to determine the specific location of NDRG2 protein in subcellular level. A eukaryotic expression vector pIRES2-EGFP-NDRG2 was successfully constructed. After NDRG2 transfection, the growth of OS-RC-2 cells was inhibited. Flow cytometry showed that cells were arrested in S phase but the peak of cell apoptosis was not present, and confocal laser scanning microscopy showed that NDRG2 protein was located in mitochondrion. In conclusion, NDRG2 can significantly inhibit the proliferation of OS-RC-2 cells in vitro and its protein is specifically expressed in the mitochondrion.     

抑癌基因NPRL2对肾癌786-O细胞增殖和凋亡的影响

抑癌基因NPRL2(nitrogen permease regulator-like 2)在人类许多正常组织中均有明显的表达,而在人类多种肿瘤组织中的表达明显降低。该实验通过构建重组质粒pEGFP-N1-NPRL2并转染肾癌786-O细胞株,应用倒置荧光显微镜、RT-PCR和Western blot检测NPRL2基因的表达情况;MTT法检测786-O细胞增殖的情况;流式细胞仪分析细胞周期和细胞凋亡情况。结果显示:肾癌786-O细胞株转染重组质粒pEGFP-N1-NPRL2后,通过荧光显微镜可以观察到绿色荧光;RT-PCR和Western blot检测到NPRL2基因的转录和蛋白质表达水平明显增加(P<0.05);MTT法检测发现72 h时pEGFP-N1-NPRL2组、pEGFP-N1组和空白对照组的细胞D490值分别为0.654±0.030、1.528±0.022和1.572±0.036,pEGFP-N1-NPRL2组细胞的增殖较其他两组受到明显的抑制(P<0.05);流式细胞仪检测显示pEGFP-N1-NPRL2组、pEGFP-N1组和空白对照组的凋亡率分别为18.82%±0.40%、5.65%±0.12%和5.85%±0.07%,而处于G0/G1期的细胞比例分别为69.80%±1.40%、46.24%±1.30%和47.03%±0.45%,与其他两组相比,pEGFP-N1-NPRL2组的凋亡率显著增高而且G0/G1期细胞明显增多,表现出G0/G1期阻滞。提示抑癌基因NPRL2的转染可以抑制786-O细胞的增殖,并诱导其凋亡将细胞周期阻滞于G0/G1期。     

Tumor Suppressor p53 Down-Regulates Tissue-Specific Expression of Tyrosinase Gene in Human Melanoma Cell Lines

Tyrosinase, the key gene in melanin pigment synthesis, is tissue-specifically expressed in melanocytic cells. Expression of this gene is regulated by various hormones, carcinogens, and environmental factors. The molecular basis underlying tyrosinase gene regulation is still not clear. In this report, we present the effects of tumor suppressor p53 protein on tyrosinase gene expression and melanin synthesis in human melanoma. After stable transfection of wild type p53 expression plasmid into a highly pigmented melanoma cell line, overexpression of wt p53 suppressed the pigmentation of the melanoma cells. The loss of pigmentation was associated with the loss of endogenous tyrosinase expression at the activity and mRNA levels. In order to determine whether the p53 repression of tyrosinase mRNA involved modulation of tyrosinase promoter activity, transient transfection approaches involving p53 expression plasmid and construct containing chloramphenicol acetyl transferase (CAT) reporter gene linked to 270 bp tissue-specific tyrosinase promoter have been used. p53 specifically repressed CAT gene expression from the tyrosinase promoter and not from the Rous sarcoma virus promoter. These data suggest that in human melanoma p53 down-regulates the tissue-specific expression of tyrosinase gene and subsequent melanin synthesis.     

Evidence for a Tumor Suppressor Role for the Large Tumor Suppressor Genes LATS1 and LATS2 in Human Cancer

The role of Large tumor suppressor LATS/Warts in human cancer is not clearly understood. Here we show that hLATS1/2 cancer mutations affect their expression and kinase activity. hLATS1/2 mutants exhibit a decreased activity in inhibiting YAP and tissue growth. Therefore, hLATS1/2 alleles from human cancer can be loss-of-function mutations.     

Ndrg2基因表达对胃癌细胞增殖调控及其机理的研究

为研究Ndrg2基因在人类肿瘤发生发展中的作用,以不表达Ndrg2基因的胃癌细胞系HGC-27和表达Ndrg2基因的胃癌细胞系SGC-7901作为对比材料,以Ndrg2基因转染HGC-27胃癌细胞系,以及用Ndrg2的反义寡核苷酸封闭SGC-7901胃癌细胞系中Ndrg2基因的表达.发现Ndrg2可以抑制HGC-27胃癌细胞的软琼脂集落形成,有一定诱导细胞凋亡的作用,对细胞周期蛋白E的表达有明显下调作用.当封闭了SGC-7901胃癌细胞中Ndrg2基因表达的软琼脂集落形成受到抑制,流式细胞仪检测发现此时的SGC-7901细胞周期被阻滞在G1期,细胞周期蛋白D1和E表达下调.Ndrg2基因对两种肿瘤细胞中的细胞外信号调节激酶(ERK)和P38的表达也有不同的影响.     

Hypertonic Stress Induces VEGF Production in Human Colon Cancer Cell Line Caco-2: Inhibitory Role of Autocrine PGE2

Vascular Endothelial Growth Factor (VEGF) is a major regulator of angiogenesis. VEGF expression is up regulated in response to micro-environmental cues related to poor blood supply such as hypoxia. However, regulation of VEGF expression in cancer cells is not limited to the stress response due to increased volume of the tumor mass. Lipid mediators in particular arachidonic acid-derived prostaglandin (PG)E₂ are regulators of VEGF expression and angiogenesis in colon cancer. In addition, increased osmolarity that is generated during colonic water absorption and feces consolidation seems to activate colon cancer cells and promote PGE₂ generation. Such physiological stimulation may provide signaling for cancer promotion. Here we investigated the effect of exposure to a hypertonic medium, to emulate colonic environment, on VEGF production by colon cancer cells. The role of concomitant PGE₂ generation and MAPK activation was addressed by specific pharmacological inhibition. Human colon cancer cell line Caco-2 exposed to a hypertonic environment responded with marked VEGF and PGE₂ production. VEGF production was inhibited by selective inhibitors of ERK 1/2 and p38 MAPK pathways. To address the regulatory role of PGE₂ on VEGF production, Caco-2 cells were treated with cPLA₂ (ATK) and COX-2 (NS-398) inhibitors, that completely block PGE₂ generation. The Caco-2 cells were also treated with a non selective PGE₂ receptor antagonist. Each treatment significantly increased the hypertonic stress-induced VEGF production. Moreover, addition of PGE₂ or selective EP₂ receptor agonist to activated Caco-2 cells inhibited VEGF production. The autocrine inhibitory role for PGE₂ appears to be selective to hypertonic environment since VEGF production induced by exposure to CoCl₂ was decreased by inhibition of concomitant PGE₂ generation. Our results indicated that hypertonicity stimulates VEGF production in colon cancer cell lines. Also PGE₂ plays an inhibitory role on VEGF production by Caco-2 cells exposed to hyperosmotic stress through EP₂ activation.     

Cellular Retinoic Acid Binding Protein 2 Is Strikingly Downregulated in Human Esophageal Squamous Cell Carcinoma and Functions as a Tumor Suppressor

Esophageal squamous cell carcinoma (ESCC) is the predominant pathotype of esophageal carcinoma (EC) in China, especially in Henan province, with poor prognosis and limited 5-year survival rate. Cellular retinoic acid binding protein 2 (CRABP2) is a member of the retinoic acid (RA) and lipocalin/cytosolic fatty-acid binding protein family and plays a completely contrary role in tumorigenesis through the retinoid signaling pathway, depending on the nuclear RA receptors (RAR) and PPARbeta/delta receptors. Presently, the biological role of CRABP2 in the development of ESCC has never been reported. Here, we firstly evaluated the expression of CRABP2 at both mRNA and protein levels and showed that it was remarkably downregulated in clinical ESCC tissues and closely correlated with the occurrence position, pathology, TNM stage, size, infiltration depth and cell differentiation of the tumor. Additionally, the biological function assays demonstrated that CRABP2 acted as a tumor suppressor in esophageal squamous carcinogenesis by significantly inhibiting cell growth, inducing cell apoptosis and blocking cell metastasis both in vitro and in vivo. All in all, our finding simplicate that CRABP2 is possibly an efficient molecular marker for diagnosing and predicting the development of ESCC.