Expression of cytokeratin 19 mRNA in human lung cancer cell lines.

The present study was designed to clarify the mechanism by which some lung cancer cell lines can produce cytokeratin 19 (CK19) fragment and others cannot. We hypothesized that some lung cancer cell lines which cannot release CK19 express an incomplete sequence of CK19 mRNA. Expression of mRNA was evaluated by RT-PCR using several primer pairs for CK19. CK19 in the culture supernatant was measured by an immuno-radiometric assay. CK19 protein synthesis was evaluated by Western immunoblot and immunohistochemistry. Among 16 lung cancer cell lines, 7 released significant amounts of CK19 in the supernatant. In some cell lines, expression of CK19 mRNA was observed only in some combinations of primers, suggesting that incomplete mRNA was expressed. 3'-RACE analysis detected amplified products of a shorter size compared with normal amplified products in cell lines which expressed incomplete CK19 mRNA, suggesting that 3'-ends of mRNA for CK19 were deleted. Results of Western immunoblot and immuno-histochemical staining using anti-human CK19 monoclonal antibody completely correlated with the results on CK19 levels in culture supernatants as well as with complete expression of mRNA. We conclude that levels of CK19 closely relate to the expression of complete mRNA for CK19.     

食管癌细胞系中MT-3基因CpG岛甲基化的意义

目的研究食管癌细胞系中MT-3基因CpG岛甲基化与其mRNA表达的关系。方法选取4种食管癌细胞系OE21，OE19，OE33和TE7，经重亚硫酸钠处理后，采用限制性酶切图谱分析(COBRA)和逆转录聚合酶链反应(RT-PCR)技术，在DNA甲基转移酶抑制剂5-氮2^ -脱氧胞苷(5-aza-CdR)处理前后，对其MT-3基因CpG岛的甲基化情况及mRNA的表达情况进行对比研究。结果4种食管癌细胞系的MT-3基因均存在不同程度的CpG岛超甲基化。经5-aza-CdR处理后，超甲基化状态解除，mRNA的表达水平也较处理前明显提高(P=0.002)。结论食管癌细胞系中MT-3基因CpG岛的超甲基化可抑制其mRNA表达。当其超甲基化解除后，MT-3基因的mRNA表达水平也会相应升高。     

人核糖体蛋白S13(RPS13)编码基因的克隆及其正反义核酸转染胃癌细胞的初步研究

目的：扩增人核糖体蛋白S13（RPS13）编码基因序列，构建其正，反义真核表达载体，分别转染胃癌细胞SGC7901及胃癌耐药细胞SGC7901/VCR，以进一步研究RPS13基因与胃癌多药耐药的关系。方法：采用RT-PCR法扩增RPS13cDNA片段编码区全长序列，利用DNA重组技术的建正，反义真核表达载体，经脂质体介导转染胃癌细胞SGC7901及胃癌耐药细胞SGC7901/VCR，筛选正，反义基因稳定转染细胞，RNA斑点杂交法检测正，反义稳定转染细胞mRNA水平的变化。结果：从高表达RPS13的SGC7901/VCR耐药细胞中提取细胞总RNA，RT-PCR法成功扩增了RPS13cDNA片段编码区全长序列，并经测序证实；目的基因因按正，反两个方向亚克隆至真核表达载体pcDNA3.1( ),并经酶切鉴定证实；经脂质体介导将正义真核表达载体转染SGC7901细胞，反义真核表达载体转染SGC7901/VCR细胞，G418筛选获得稳定转染细胞；RNA斑点杂交试验证实；正义稳定转染细胞RPS13mRNA水平上调，反义稳定转染细胞RPS13mRNA水平下调。结论：成功克隆了人RPS13编码基因序列，并构建了其正，反义真核表达载体，在胃癌细胞系SGC7901及长春新碱耐药细胞SGC7901/VCR中得到稳定转染细胞，正义转染细胞中RPS13mRNA表达明显增加，反义转染细胞中表达明显受抑。     

SOX30基因在结直肠癌中的表达与甲基化分析

目的:探讨新发现的抑癌基因SRY盒包含基因30(SOX30)在结直肠癌中的表达及甲基化变化。方法:用逆转录PCR(RT-PCR)检测结直肠癌细胞株(HCT8、HCT116和SW480)中SOX30 mRNA的表达,利用去甲基化药物5-Aza-CdR处理结直肠癌细胞株72 h后检测SOX30基因高甲基化与其表达调控的关系。应用甲基化特异性PCR(MSP)检测上述3株结直肠癌细胞株及54例结直肠肿瘤组织和10例癌旁组织SOX30基因的甲基化发生情况,通过硫化测序PCR(BSP)验证结直肠癌组织和癌旁组织SOX30基因的甲基化改变,并对甲基化情况与结直肠癌患者病理特征进行相关性分析。结果:SOX30 mRNA在上述3株结直肠癌细胞株中表达与对照组相比均较低,且均发生明显高甲基化;去甲基化药物处理上述3株细胞株后,SOX30 mRNA的表达明显得到恢复。SOX30基因在大部分结直肠癌组织中均呈现高甲基化状态,甲基化发生率为79.6%(43/54);而在相应的癌旁组织中甲基化检出率较低,仅为20%(2/10)。对结直肠癌患者中SOX30基因甲基化与其临床病理学资料进行相关性分析发现,SOX30基因高甲基化与患者的肿瘤病理分型显著相关(P=0.045),而与患者的性别、年龄、吸烟与否、TNM分期和Ducks分期无显著相关性(P均>0.05)。结论:SOX30基因在结直肠癌中发生明显高甲基化修饰改变,其基因表达水平明显下调,而且其甲基化修饰率与患者肿瘤病理分型相关,提示SOX30可能在结直肠癌的发生过程中起重要作用。     

Detection of amplified DNA sequences in gastric cancers by a DNA renaturation method in gel

A DNA renaturation method in gel was used to detect amplified DNA fragments in eight gastric cancer cell lines, KATO-III, OKAJIMA, SCH, MKN1, MKN7, MKN28, MKN45 and MKN74 cells, and tissues of three metastases of gastric cancers to lymph nodes. There were amplified DNA sequences in three gastric cancer cell lines. Judging from the intensities of the bands, HindIII-digested DNA fragments were amplified several hundred times in the KATO-III and MKN7 cell lines. DNA from OKAJIMA cell line contained multiple bands with less intensity. KATO-III cells were found to contain a homogeneously staining region in chromosome 11.     

Atypical multidrug resistance: breast cancer resistance protein messenger RNA expression in mitoxantrone-selected cell lines

BACKGROUND: Human cancer cell lines grown in the presence of the cytotoxic agent mitoxantrone frequently develop resistance associated with a reduction in intracellular drug accumulation without increased expression of the known drug resistance transporters P-glycoprotein and multidrug resistance protein (also known as multidrug resistance-associated protein). Breast cancer resistance protein (BCRP) is a recently described adenosine triphosphate-binding cassette transporter associated with resistance to mitoxantrone and anthracyclines. This study was undertaken to test the prevalence of BCRP overexpression in cell lines selected for growth in the presence of mitoxantrone. METHODS: Total cellular RNA or poly A+ RNA and genomic DNA were isolated from parental and drug-selected cell lines. Expression of BCRP messenger RNA (mRNA) and amplification of the BCRP gene were analyzed by northern and Southern blot hybridization, respectively. RESULTS: A variety of drug-resistant human cancer cell lines derived by selection with mitoxantrone markedly overexpressed BCRP mRNA; these cell lines included sublines of human breast carcinoma (MCF-7), colon carcinoma (S1 and HT29), gastric carcinoma (EPG85-257), fibrosarcoma (EPF86-079), and myeloma (8226) origins. Analysis of genomic DNA from BCRP-overexpressing MCF-7/MX cells demonstrated that the BCRP gene was also amplified in these cells. CONCLUSIONS: Overexpression of BCRP mRNA is frequently observed in multidrug-resistant cell lines selected with mitoxantrone, suggesting that BCRP is likely to be a major cellular defense mechanism elicited in response to exposure to this drug. It is likely that BCRP is the putative "mitoxantrone transporter" hypothesized to be present in these cell lines.     

人肺癌细胞株中hnRNP A2/B1表达的研究

目的 研究人肺癌细胞株中核内不均一核糖核蛋白(hnRNP)A2/B1及hnRNP B1的表达。方法 采用特异性hnRNP A2／B2及hnRNP B1引物,应用RT-PCR方法研究肺癌细胞株hnRNP A2／B1 mRNA的表达,以抗hnRNP B1单克隆抗体免疫细胞化学染色方法研究肺癌细胞hnRNP A2/B1蛋白的亚细胞定位。结果 RT—PCR显示人肺腺癌细胞株SPC-A1及Y-90,小细胞肺癌细胞株NCI-H446及鳞癌细胞株A431均表达hnRNP A2／B1及hnRNP B1,其PCR产物分子量分别在661及1039bp左右,与预期大小的hnRNP A2/B1 cDNA片断相符。免疫细胞化学研究发现,肺腺癌细胞株SPC—A1及Y-90．小细胞肺癌细胞株NCI—H446及鳞癌A431的细胞浆及细胞核内均可见特异的hnRNP B1染色,鳞癌A43l及小细胞肺癌NCI—H446 hnRNP B1染色较肺腺癌细胞株SPC—A1及Y-90明显。结论 肺癌细胞株hnRNP A2／B1及hnRNP B1表达明显增高。     

bcr-abl基因真核表达载体的构建及其在COS-7细胞中的表达

目的 构建慢性粒细胞白血病bcr-abl融合基因的真核表达载体,并在哺乳动物细胞COS-7中高效表达.方法 提取慢性粒细胞白血病K562细胞的RNA,经RT-PCR技术扩增得到bcr-abl基因后,将其克隆入真核表达载体pEGFP-N3中,并进行PCR和酶切鉴定.鉴定为阳性的克隆,再进一步进行测序分析.将构建成功的真核表达载体转入COS-7细胞中进行瞬时表达.结果 反转录PCR扩增后的产物,经琼脂糖凝胶电泳可以在约874 bp处看见一特异性的条带,序列分析证明扩增产物与GeneBank中的bcr-abl基因序列相同.将pEGFP-bcr-abl真核表达载体转入COS-7细胞后,经RT-PCR、Western blotting检测证明表达产物正确.结论 成功构建了含有bcr-abl融合基因的真核表达质粒,从而为进一步研究其结构和功能,寻找CML诊疗的新方法奠定了基础.     

bcr-abl基因真核表达载体的构建及其在COS-7细胞中的表达

 目的　构建慢性粒细胞白血病bcr-abl融合基因的真核表达载体,并在哺乳动物细胞COS-7中高效表达。方法　提取慢性粒细胞白血病K562细胞的RNA,经RT-PCR技术扩增得到bcr-abl基因后,将其克隆入真核表达载体pEGFP-N3中,并进行PCR和酶切鉴定。鉴定为阳性的克隆,再进一步进行测序分析。将构建成功的真核表达载体转入COS-7细胞中进行瞬时表达。结果　反转录PCR扩增后的产物,经琼脂糖凝胶电泳可以在约874 bp处看见一特异性的条带,序列分析证明扩增产物与Gene Bank中的bcr-abl基因序列相同。将pEGFP- bcr-abl真核表达载体转入COS-7细胞后,经RT-PCR、Western blotting检测证明表达产物正确。结论　成功构建了含有bcr-abl融合基因的真核表达质粒,从而为进一步研究其结构和功能,寻找CML诊疗的新方法奠定了基础。     

实时荧光PCR法检测肺癌细胞系中吉西他滨耐药相关基因的表达

Objective: To explore the molecular mechanism of gemcitabine-resistance, the relative mRNA expression of five genes related to gemcitabine-resistance was detected in six lung cancer cell lines. Methods: The total RNA was extracted from six lung cancer cell lines GLC-82, NCI-H460, A549, 95-C, 95-D and QG56. Then the cDNA was amplified by real-time quantitative PCR method to quantify the gene expression of RRM1, PTEN, ERCC1, dCK and CDA. The cytotoxicity of gem- citabine to cell lines was tested by MTT method. Results: Among the detected six lung cancer cell lines, the mRNA level of RRM1, PTEN and ERCC1 in lung squamous cell line QG56 was highest, and the IC50 of gemcitabine to QG56 cell line was also highest. Conclusion: The mRNA expression of RRM1, PTEN and ERCC1 was correlated, and the high expression of RRM1 was related to gemcitabine resistance of lung cancer.     

Aurora-A激酶在人类不同肺癌细胞株中的表达

背景与目的近年来的研究发现Aurora-A在多种恶性肿瘤中高表达。本研究检测Aurora-A激酶在人类不同肺癌细胞株中的表达及其与DNA含量的关系,旨在寻找肺癌新的分子治疗靶点和肿瘤标记物,为指导肺癌个性化治疗提供一种新的方法。方法应用RT-PCR与Westernblot方法检测PG(高转移的巨细胞肺癌)、A549(肺腺癌)、NCI-H460(大细胞肺癌)3种肺癌细胞株Aurora-A的表达;流式细胞仪检测3种肺癌细胞DNA含量(四倍体及多倍体),分析Aurora-A的表达与DNA含量的相关性。结果半定量RT-PCR电泳结果显示,A549、PG、NCI-H460中Aurora-A/β-actin比值分别为1.16、1.14、0.84;Westernblot结果在A549、PG与NCI-H460中的Aurora-A/β-actin比值分别为21.13、8.96与6.43,提示3种肺癌细胞Aurora-A均呈高表达。A549、PG、NCI-H460细胞含有四倍体的细胞比例分别为14.97%、19.88%和10.60%,三者有显著性差异(P<0.01);其多倍体(>4N)的细胞比例分别为3.59%、2.66%、2.30%。提示Aurora-A表达强弱与肺癌细胞多倍体的比例高低有相关性。结论3种肺癌细胞中Aurora-A基因均高表达,其表达水平在不同肺癌细胞株中存在差异。