ODC, AdoMetDC双反义腺病毒对肺癌增殖和侵袭抑制作用的体外和体内研究

鸟氨酸脱羧酶(ODC)和S-甲硫氨酸脱羧酶(AdoMetDC)是多胺体内合成的2个关键酶.研究腺病毒Ad-ODC-AdoMetDCas介导的ODC和AdoMetDC反义RNA对肺癌多胺合成,细胞增殖以及侵袭的抑制作用.用活细胞计数和流式细胞术分别检测Ad-ODCas和Ad-ODC-AdoMetDCas对肺癌A-549细胞增殖的影响,蛋白质印迹和HPLC方法分别检测腺病毒对肺癌A-549细胞中ODC和AdoMetDC蛋白表达以及胞内多胺含量的抑制作用,TUNEL标记检测法观察Ad-ODC-AdoMetDCas对肺癌细胞凋亡的影响,Matrigel侵袭实验分析腺病毒对肺癌A-549细胞侵袭活性的改变,裸鼠皮下移植瘤模型研究Ad-ODC-AdoMetDCas对体内肺癌生长的抑制作用.实验结果显示,Ad-ODC-AdoMetDCas明显抑制肺癌A-549细胞的增殖,导致细胞凋亡,显著降低肺癌A-549细胞的体外侵袭能力,肺癌A-549细胞感染Ad-ODC-AdoMetDCas后细胞内3种多胺含量都明显降低,Ad-ODC-AdoMetDCas对已形成的裸鼠皮下移植瘤具有明显的抑制作用.实验表明,ODC和AdoMetDC双反义腺病毒具有显著抑制肺癌增殖和侵袭的作用,对于肺癌的防治研究具有一定的前景.     

ODC和AdoMetDC双反义腺病毒载体对食管癌细胞凋亡影响的研究

为探讨ODC和AdoMetDC双反义腺病毒载体(Ad-ODC-AdoMetDCas)对食管癌Eca109细胞凋亡作用的影响,应用MTT法观察Ad-ODC-AdoMetDCas对食管癌Eca109细胞生长增殖的影响,采用Western blot和HPLC的方法分别检测腺病毒载体对食管癌Eca109细胞中ODC和AdoMetDC蛋白表达以及胞内多胺含量的抑制作用,同时应用原位末端标记(TUNEL) 法观察Ad-ODC-AdoMetDCas对食管癌Eca109细胞凋亡作用的影响, 透射电镜进一步观察细胞超微结构的改变． 实验结果显示,应用MTT法观察发现Ad-ODC-AdoMetDCas对食管癌Eca109细胞生长增殖有显著抑制作用． 以Ad-ODC- AdoMetDCas感染食管癌Eca109细胞,可明显抑制食管癌Eca109细胞中ODC和AdoMetDC基因表达． HPLC结果显示,食管癌Eca109细胞感染Ad-ODC-AdoMetDCas后,细胞内3种多胺含量都明显降低． TUNEL标记检测结果显示Ad-ODC-AdoMetDCas可明显引起食管癌Eca109细胞凋亡．透射电镜观察到典型的细胞凋亡特征(表现细胞体积缩小,核皱缩、碎裂,染色质呈块状边集等)． 实验表明,ODC和AdoMetDC双反义腺病毒载体(Ad-ODC-AdoMetDCas)具有显著抑制食管癌细胞生长增殖,降低细胞多胺合成,促进细胞凋亡,为探讨食管癌基因治疗的可行性提供实验依据．     

Adenovirus-mediated expression of both antisense ornithine decarboxylase and S-adenosylmethionine decarboxylase inhibits lung cancer cell growth

Polyamine biosynthesis is controlled primarily by ornithine decarboxylase (ODC) and Sadenosylmethionine decarboxylase (AdoMetDC). Antisense sequences of ODC and AdoMetDC genes were cloned into an adenoviral vector (named Ad-ODC-AdoMetDCas). To evaluate the effects of recombinant adenovirus Ad-ODC-AdoMetDCas that can simultaneously express both antisense ODC and AdoMetDC, the human lung cancer cell line A-549 was infected with Ad-ODC-AdoMetDCas or the control vector. Viable cell counting, determination of polyamine concentrations, cell cycle analysis, and Matrigel invasion assays were carried out to assess the properties of tumor growth and invasiveness. Our study showed that adenovirus-mediated antisense ODC and AdoMetDC expression inhibits tumor cell growth through blocking the polyamine synthesis pathway. Tumor cells were arrested at the G_1 phase after gene transfer and the invasiveness was reduced. It suggested that the recombinant adenovirus Ad-ODC-AdoMetDCas might be a new anticancer reagent in the treatment of lung cancers.     

鸟氨酸脱羧酶基因反义RNA对前列腺癌细胞生长的抑制作用

为研究鸟氨酸脱羧酶 (ODC)基因反义RNA对前列腺癌细胞的生长抑制作用 ,将表达ODC第 3外显子反义RNA的重组腺病毒rAd ODC Ex3as分别感染前列腺癌细胞株PC 3和LNCap .通过MTT法观察其对前列腺癌细胞增殖的影响 ,并确定不同细胞合适的感染滴度 ,再采用Western印迹和流式细胞术检测rAd ODC Ex3as对细胞中ODC表达的抑制作用、对细胞周期和凋亡的影响以及与CDK抑制物p2 1的关系 .实验显示 ,rAd ODC Ex3as分别以 5 0MOI、2 5MOI感染PC 3和LNCap细胞可明显抑制其生长增殖 ,而不引起细胞毒性作用 ;其对两种细胞中ODC表达的抑制作用分别为4 5 %和 5 9% .流式细胞DNA含量分析证实 ,rAd ODC Ex3as可引起PC 3和LNCap细胞周期G1期阻滞 ,但并未引起凋亡 .通过Western印迹发现 ,细胞中ODC表达的降低可诱导p2 1蛋白的过表达 .结果表明 ,rAd ODC Ex3as在体外能有效地干扰ODC基因的表达 ,并通过诱导p2 1的过表达使其细胞周期停于G1期 ,从而抑制前列腺癌细胞PC 3和LNCap的增殖 ,为其进一步基因治疗的研究打下基础 .     

鸟氨酸脱羧酶基因反义RNA对淋巴瘤细胞Jurkat生长的影响

探讨鸟氨酸脱羧酶(ornithine decarboxylase,ODC)反义RNA是否对人淋巴瘤细胞Jurkat的生长具有抑制作用。含反义RNA的真核表达载体pcDNA3.1(+)/Rodc用脂质体转染Jurkat细胞,G418筛选ODC表达抑制的细胞株,MTS法分析细胞增殖,Western blotting检测细胞中ODC蛋白表达水平,半定量RT-PCR检测细胞中ODC mRNA含量,流式细胞术检测细胞周期的变化,DNA片段化分析细胞凋亡。结果显示,成功获得ODC表达抑制的淋巴瘤细胞株J/o,ODC反义RNA转染细胞后,引起Jurkat细胞生长缓慢和S/G2细胞周期停滞,细胞对抗癌药物DFMO敏感性显著增加。由此证明,ODC反义RNA能抑制人T淋巴瘤Jurkat细胞的生长,具有治疗人白血病的潜在应用价值。     

维胺酸对体外转化人支气管上皮细胞及体内构建人支气管上皮组织的抑制作用

癌前改变是肿瘤演变过程中的关键阶段。许多研究显示维甲类化合物对动物肿瘤及体外恶性细胞系具有抑制作用,但尚未见其对肺癌前病变作用的实验室研究报道。人类肺癌的绝大部分起源于支气管上皮,为研究维胺酸对体外转化人支气管上皮M细胞系以及在大鼠气管构建后移植到裸鼠体内生长的具有癌前病变特点的人支气管上皮组织的抑制作用,采用上皮细胞无血清培养技术,人支气管上皮组织大鼠气管内构建／裸鼠皮下移植生长技术,流式细胞学分析,免疫组化、凋亡细胞原位末端标记以及病理学检查等研究方法发现,维胺酸可抑制体外培养的转化人支气管上皮细胞的增殖,使S期细胞比例下降,以及细胞增殖标志Ki-67、mpm-2阳性反应细胞比例下降;明显诱导细胞凋亡。裸鼠腹腔注射给予维胺酸也可使大鼠气管内构建后移植到裸鼠体内生长的癌前期人支气管上皮组织的生长率明显降低,病变程度明显减轻;同样可以诱导细胞凋亡。研究结果提示,维胺酸对体外培养的转化人支气管上皮细胞系及大鼠气管构建／裸鼠体内移植生长的人支气管上皮组织均有明显的抑制作用,是有希望的肺癌化学预防药物。     

姜黄素对A549肺癌细胞增殖、侵袭和迁移的抑制作用及与Keap1/Nrf2信号通路的关系

目的探究姜黄素对肺癌A549细胞增殖、侵袭和迁移的抑制作用及其机制。方法通过MTT法检测姜黄素对A549细胞增殖能力的影响;通过流式细胞术测定姜黄素对A549细胞凋亡的调节作用;通过Transwell试验,观察姜黄素对肺癌A549细胞的侵袭和迁移能力的影响;采用Western blot实验和RT-PCR实验,观察姜黄素对其Keap1/Nrf2信号通路的调节作用。结果增殖实验、凋亡实验和Transwell实验显示,姜黄素能够显著性抑制癌细胞的增殖、侵袭和迁移,并能够促进其凋亡。Western blot检测显示姜黄素能够显著抑制Keap1和Nrf2表达;RT-PCR实验结果显示姜黄素能够显著抑制Keap1mRNA和Nrf2 mRNA表达。结论姜黄素可能通过抑制Keap1/Nrf2信号通路蛋白的表达而抑制肺癌A549细胞的增殖、迁移和侵袭,并促进其凋亡。     

RGD肽对肺癌A549 细胞增殖侵袭能力的影响及其机制研究

目的:研究RGD肽对肺癌A549细胞增殖凋亡及侵袭迁移的影响,并探讨其作用机制。方法:不同浓度RGD肽处理肺癌A549细胞后,MTT检测肺癌细胞的增殖能力,流式细胞仪检测肺癌细胞凋亡及周期分布,Transwell检测其迁移及侵袭能力的变化,Western blot检测RGD肽对肺癌A549细胞MMP2、MMP9的表达水平影响。结果:当RGD肽浓度增加至50 mg/L时,肺癌A549细胞增殖明显受到抑制,且这种抑制作用呈剂量依赖关系;RGD肽组A549细胞G0/G1期细胞比例增高,细胞凋亡率由(6.1±0.1)%增至(15.2±0.5)%;在迁移和侵袭试验中,RGD肽组A549细胞的穿膜细胞数分别由123±10和43±10降至45±5和18±5;RGD肽组A549细胞MMP2、MMP9表达水平显著降低。结论:RGD肽对肺癌A549细胞的增殖有明显抑制作用,并促进其凋亡,可能与RGD肽改变其周期分布有关,RGD肽可明显抑制A549细胞的迁移及侵袭,可能与其下调MMP2、MMP9的表达相关。     

沙棘总黄酮抑制肺癌A549增殖和迁移作用及机理

为探究三种沙棘总黄酮(TFH)对非小细胞肺癌A549细胞增殖及迁移的影响,并探讨其分子作用机制,选择不同浓度的西藏沙棘(Hippophae tibetana Schlecht)、中国沙棘(H.rhamnoides L.subsp.sinensis Rousi)、肋果沙棘(H.neurocarpa)总黄酮作用于A549细胞。通过MTT检测细胞相对活力,平板克隆形成实验及软琼脂克隆形成实验检测细胞克隆形成能力,流式细胞仪AnnexinV/PI双染法检测细胞凋亡比例。选择效果最佳的西藏沙棘总黄酮应用细胞划痕实验及Transwell实验分析该化合物对肺癌细胞迁移侵袭能力的影响。Western blot检测MMP9、E-cadherin等侵袭迁移相关蛋白表达。敲低E-cadherin基因检测沙棘总黄酮对细胞迁移能力的影响。结果显示,三种沙棘总黄酮均对A549细胞系具有增殖抑制作用,抑制作用依次为:西藏沙棘中国沙棘肋果沙棘。西藏沙棘总黄酮可显著性抑制非小细胞肺癌A549细胞侵袭迁移能力(P0.05)。实验组中MMP9、MMP2、TGF-β、N-cadherin表达水平显著降低,E-cadherin表达水平上调。我们发现在A549细胞中敲低E-cadherin,西藏沙棘总黄酮可逆转迁移增加。以上研究表明西藏沙棘总黄酮对肺癌A549增殖抑制作用具有明显的优势,且西藏沙棘总黄酮可明显抑制肺癌A549细胞的侵袭迁移能力,并可能与下调细胞中的TGF-β抑制MMP9表达并阻止肺癌EMT有关。     

hS100A6对人骨肉瘤细胞株143B的体内体外作用

为研究hS100A6对人骨肉瘤细胞系143B的体内体外作用,利用整合有S100A6基因和SiS100A6基因的腺病毒(AdS100A6和AdSiS100A6)作用于143B细胞,MTT法和台盼蓝染色法检测其对细胞的增殖作用,Hoechst染色法检测其对凋亡的作用,Transwell实验检测其对迁移的作用,同时以143B裸鼠皮下移植瘤为动物模型,检测S100A6对143B的体内作用,结果显示AdS100A6干预后出现细胞增殖活性的减弱、凋亡率增高、迁移率降低,在体内试验中瘤体体积明显较对照组减小,而AdsiS100A6干预后出现时间依赖性地细胞增殖活性的增强、凋亡率降低、迁移率增高,体内试验中瘤体体积较对照组明显增大.提示hS100A6能抑制人骨肉瘤细胞株143B细胞的增殖和迁移,并促进细胞凋亡,同时能抑制人骨肉瘤细胞株143B的裸鼠皮下移植瘤的生长.     

Polyamine depletion by ODC-AdoMetDC antisense adenovirus impairs human colorectal cancer growth and invasion in vitro and in vivo

BACKGROUND: Polyamine biosynthesis is controlled primarily by ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC). Polyamine concentrations are elevated in colorectal cancer. Depletion of polyamine content in colorectal cancer by chemotherapy is related to tumor regression and impaired tumorigenicity. The current study evaluates the therapeutic effects of antisense ODC and AdoMetDC sequences on colorectal cancer in vitro and in vivo. METHODS: Antisense ODC and AdoMetDC sequences were cloned into an adenoviral vector (Ad-ODC-AdoMetDCas). The human colon cancer cell lines, HT-29 and Caco-2, were infected with Ad-ODC-AdoMetDCas as well as with control vector. Viable cell counting, determination of polyamine concentrations, cell cycle analysis, and Matrigel invasion assays were performed in order to assess properties of tumor growth and invasiveness. Furthermore, the antitumor effects of Ad-ODC-AdoMetDCas were also evaluated in vivo in a nude mouse tumor model. RESULTS: Our study demonstrated that adenovirus-mediated ODC and AdoMetDC antisense expression inhibits tumor cell growth through a blockade of the polyamine synthesis pathway. This inhibitory effect cannot be reversed by the administration of putrescine. Tumor cells were arrested at the G1 phase of the cell cycle after gene transfer and had reduced invasiveness. The adenovirus also induced tumor regression in established tumors in nude mice. CONCLUSIONS: Our study suggests that Ad-ODC-AdoMetDCas has antitumor activity and therapeutic potential for the treatment of colorectal cancer.     

Adenovirus-mediated expression of both antisense ornithine decarboxylase and s-adenosylmethionine decarboxylase induces G1 arrest in HT-29 cells

To evaluated the effect of recombinant adenovirus Ad-ODC-AdoMetDCas which can simultaneously express both antisense ornithine decarboxylase (ODC) and Sadenosylmethionine decarboxylase (AdoMetDC) on cell cycle distribution in colorectal cancer cell and investigated underlying regulatory responses, human colorectal cancer cells HT-29 were cultured in RPMI 1640 medium and infected with Ad-ODC-AdoMetDCas. Cell cycle progression was detected by flow cytometry analysis. The expression levels of cell cycle regulated proteins were measured by Western blot analysis. The mRNA level of cyclin D1 was measured by RT-PCR. And a luciferase reporter plasmid of cyclin D1 promoter was constructed to observe the effect of Ad-ODC-AdoMetDCas on cyclin D1 promoter activity. The results showed that recombinant adenovirus Ad-ODC-AdoMetDCas significantly induced G1 arrest, decreased levels of cyclin D1 protein and mRNA and suppressed the promoter activity. Ad-ODC-AdoMetDCas also inhibited nuclear translocation of beta-catenin. In conclusion, downregulation of ODC and AdoMetDC mediated by Ad-ODC-AdoMetDCas transfection induces G(1) arrest in HT-29 cells and the arrest was associated with suppression of cyclin D1 expression and inhibition of beta-catenin nuclear translocation. As a new anticancer reagent, the recombinant adenovirus Ad-ODC-AdoMetDCas holds promising hope for the therapy of colorectal cancers.     

Decarboxylases involved in polyamine biosynthesis and their inactivation by nitric oxide

Polyamines are ubiquitous cellular components that are involved in normal and neoplastic growth. Polyamine biosynthesis is very highly regulated in mammalian cells by the activities of two key decarboxylases acting on ornithine and S-adenosylmethionine. Recent studies, which include crystallographic analysis of the recombinant human proteins, have provided a detailed knowledge of their structure and function. Ornithine decarboxylase is a PLP-requiring decarboxylase, whereas S-adenosylmethionine decarboxylase (AdoMetDC) contains a covalently bound pyruvate prosthetic group. Both enzymes have a key cysteine residue, which is involved in protonation of the Schiff base intermediate C(alpha) to form the product. These residues, Cys360 in ornithine decarboxylase (ODC) and Cys82 in AdoMetDC, react readily with nitric oxide (NO), which is therefore a potent inactivator of polyamine synthesis. The inactivation of these enzymes may mediate some of the antiproliferative actions of NO.     

Concomitant Changes in Polyamine Pools and DNA Methylation during Growth Inhibition of Human Colonic Cancer Cells

The effects of CGP 48664 and DFMO, selective inhibitors of the key enzymes of polyamine biosynthesis, namely, ofS-adenosylmethionine decarboxylase (AdoMetDC) and ornithine decarboxylase (ODC), were investigated on growth, polyamine metabolism, and DNA methylation in the Caco-2 cell line. Both inhibitors caused growth inhibition and affected similarly the initial expression of the differentiation marker sucrase. In the presence of the AdoMetDC inhibitor, ODC activity and the intracellular pool of putrescine were enhanced, whereas the spermidine and spermine pools were decreased. In the presence of the ODC inhibitor, the AdoMetDC activity was enhanced and the intracellular pools of putrescine and spermidine were decreased. With both compounds, the degree of global DNA methylation was increased. Spermine and spermidine (but not putrescine) selectively inhibited cytosine–DNA methyltransferase activity. Our observations suggest that spermidine (and to a lesser extent spermine) controls DNA methylation and may represent a crucial step in the regulation of Caco-2 cell growth and differentiation.