人肝癌细胞瘤QGY-7703的p53基因及其表达研究

本文利用等位基因分析,PCR-SSCP,RT-PCR/序列分析,Northern印迹,免疫组织化学,Western印迹,免疫沉淀等方法对人肝癌细胞株QGY-7703的p53基因背景进行了研究,发现17号染色体短臂可能存在等位基因缺失,在p53基因的编码序列上没有发现任何突变,但发现其mRNA和蛋白表达水平很低,表明在QGY-7703细胞中p53基因的低水平表达可能同细胞的恶性程度有关。     

血红素加氧酶-1对肝癌细胞细胞周期调控因子的影响

目的观察血红素加氧酶-1（heme oxygenase 1,HO-1）对人肝癌细胞HepG2细胞周期调控因子的影响。方法构建含有野生型和突变型HO-1基因的重组载体pcDNA3．1（＋）-wtHO-1和pcDNA3．1（＋）-mHO-1G143H。利用脂质体介导的方法将构建好的重组载体转染肝癌细胞系HepG2,以空载体转染作为对照组。通过G418筛选建立稳定表达野生型和突变型HO-1的HepG2肝癌细胞系。经半定量RT—PCR、Western印迹检测转染细胞系中HO-1 mRNA和蛋白的表达水平。在HO-1表达改变的稳转细胞系中,利用Western印迹检测转染细胞系中P21、P27蛋白表达水平。结果成功实现了野生型和突变型HO-1在HepG2细胞中的过表达;野生型和突变型HO-1过表达均能诱导抑癌基因p21和p27的表达。结论HO．1过表达诱导抑癌基因p21和p27的表达与血红素分解产物无关。HO-1可能通过其它机制调节p21和p27的表达。     

HepG2/mdr1稳定细胞系的建立及特性研究

将已构建好的含有人多药耐药（multidrug resistance, MDR）全长基因的真核表达质粒pCI-neo-mdr1,应用脂质体导入人肝癌HepG2细胞,应用G418筛选出人肝癌多药耐药细胞株HepG2/mdr1。通过对HepG2/mdr1细胞形态学的观察和生物学特性的研究,成功地建立了高效、稳定的HepG2/mdr1细胞系;为深入研究肝癌的MDR及其逆转提供了理想的细胞模型,并为探索建立肝癌MDR细胞株提供新的方法和思路,同时为研究肝癌细胞胰岛素抵抗与MDR的关系提供了模型细胞。 将已构建好的含有人多药耐药（multidrug resistance, MDR）全长基因的真核表达质粒pCI-neo-mdr1,应用脂质体导入人肝癌HepG2细胞,应用G418筛选出人肝癌多药耐药细胞株HepG2/mdr1。通过对HepG2/mdr1细胞形态学的观察和生物学特性的研究,成功地建立了高效、稳定的HepG2/mdr1细胞系;为深入研究肝癌的MDR及其逆转提供了理想的细胞模型,并为探索建立肝癌MDR细胞株提供新的方法和思路,同时为研究肝癌细胞胰岛素抵抗与MDR的关系提供了模型细胞。     

p53基因5/6外显子突变与广西肝癌高发区肝癌家族聚集性的相关性

为了研究p53基因5/6外显子突变与广西肝癌高发地区肝癌家族聚集性的关系。研究采用配对方法,选取肝癌高发家族、肝癌单发家族和无癌家族中未发生肝癌的家族成员各130例作为研究对象,同时选取上述高发地区肝癌患者30例作为肝癌组对照。应用PCR-SSCP技术检测研究对象外周血细胞DNA中p53基因5/6外显子的突变情况并进行基因测序。研究发现三组家族成员中p53基因5/6外显子的突变率为0%。肝癌组中p53基因5/6外显子的总突变率为10%(3/30)。肝癌组p53基因5/6外显子的总突变率与肝癌家族组间突变率比较,差异均具有统计学意义(p0.05)。综上,p53基因5/6外显子突变可能不是广西肝癌高发区肝癌家族聚集性的遗传易感因素,广西肝癌高发区肝癌家族成员中可能尚未发生p53基因5/6外显子突变或较为罕见,肝癌患者中出现的p53基因5/6外显子突变可能是在后天多因素的影响下发生,从而参与了肝癌的发生发展。     

AFP表达调控载体对肝癌模型的靶向治疗作用

目的观察甲胎蛋白(AFP)表达调控载体pAFP-P53-EGFP对AFP表达阳性肝癌模型靶向治疗作用。方法以人肝癌HepG2(AFP阳性)、人肝癌SMMC7721(AFP阴性)细胞于BALB/c-nu裸小鼠右腋皮下荷瘤,14d成瘤,免疫组化检测AFP。将构建好的pAFP-EGFP和pAFP-P53-EGFP重组质粒于肿瘤内注射,观察肿瘤体积变化,通过免疫组化观察p53在HepG2肿瘤中的特异性表达及对肿瘤细胞的杀伤作用。结果荷HepG2、SMMC7721细胞株裸鼠14d皮下肿瘤生长良好,且肿瘤体积均为500mm3左右,经HE染色证实造模成功。同时,AFP免疫组化结果显示接种HepG2细胞的肿瘤组织AFP表达阳性,SMMC7721细胞的肿瘤组织AFP表达为阴性。经pAFP-EGFP和pAFP-P53-EGFP重组质粒治疗后,p53的免疫组化分析结果显示接种HepG2细胞的裸鼠pAFP-P53-EGFP治疗组p53表达量显著高于其他各组,可见明显细胞凋亡现象,且肿瘤体积较对照组减小。结论含AFP基因调控序列的pAFP-P53-EGFP载体可专一性地作用于AFP阳性肝癌细胞,引起肝癌细胞周期阻滞和凋亡。     

p100蛋白表达抑制的HepG2肝癌细胞稳定株的建立

目的建立p100表达抑制的HepG2肝癌细胞稳定株,并初步探讨p100在HepG2肝癌细胞中的功能。方法用脂质体将含有真核细胞筛选标记Neo和GFP的p100 shRNA表达质粒转染入HepG2细胞。经G418耐药筛选稳定整合抗药基因的细胞单克隆;荧光镜检GFP阳性细胞单克隆,挑取单克隆;Western检测HepG2细胞稳定株HepG2（p100I）中p100表达的抑制效果;平板细胞克隆形成实验检测细胞克隆形成能力;MTS法检测细胞存活;划痕实验检测细胞迁移能力。结果成功获得了p100表达抑制的HepG2肝癌细胞稳定株HepG2（p100I）,其中p100的表达明显降低。并且实验表明,该p100表达抑制稳定株的克隆形成能力,抵抗化疗药物Cisplatin诱导的细胞死亡的能力和迁移能力明显低于对照组细胞。结论p100表达抑制的HepG2肝癌细胞稳定株的建立为研究p100蛋白在肝癌中的作用提供了体外细胞系模型,基于此稳定株的研究,发现p100能够影响HepG2肝癌细胞的多种细胞功能。     

灵芝肽诱导人肝癌HepG2细胞凋亡的研究

研究了灵芝肽(GLP)在体外对人肝癌HepG2细胞凋亡的影响,并初步探讨了其作用机制。结果显示,透射电镜下可见细胞染色质浓缩、聚集于核边缘成块状,形成典型的凋亡小体;GLP使HepG2细胞阻滞于G0/G1期,随着GLP浓度升高,其G0/G1期的细胞比例随之增加;同时细胞的早期、晚期和总的凋亡率亦均随之增加,存在剂量-效应关系;Western blotting检测结果显示,抑制凋亡基因bcl-2和survivin表达下调,而促凋亡基因p53表达上调,并且都存在剂量依赖性;细胞凋亡的关键蛋白酶caspase-3被激活,并且caspase-3酶活性与GLP浓度亦有剂量依赖性。提示GLP体外可诱导人肝癌HepG2细胞凋亡,其作用机制可能与bcl-2和survivin表达下调、p53表达上调及Caspase-3被激活有关。     

人丝氨酸蛋白酶抑制因子Hespintor的基因克隆与序列分析

目的:克隆得到人丝氨酸蛋白酶抑制因子Hespintor基因,并应用生物信息学方法进行序列分析。方法:提取HepG2细胞总RNA,RT-PCR扩增Hespintor基因片段,连接至pMD 20-T克隆载体中,转化JM109宿主菌,蓝白斑法筛选阳性克隆菌落,菌落PCR及测序鉴定。利用在线工具软件对Hespintor进行信号肽预测、亚细胞定位、结构域、三级结构、基因染色体定位及组织分布表达分析。结果:人丝氨酸蛋白酶抑制因子Hespintor基因全长285bp,共编码94aa,其中1-23aa编码信号肽,符合亚细胞定位于细胞外的预测;53-93aa编码一个典型的Kazal结构域。Hespintor基因的染色体定位于5号染色体短臂3区3带1亚带(5q33.1);正常组织中仅在睾丸有表达,而肿瘤组织中仅在生殖细胞瘤有表达。结论:Hespintor是一个在机体中静止表达的Ka-zal型丝氨酸蛋白酶抑制因子家族的分泌型新成员。     

转基因小鼠模型的载体构建和在人肝癌HepG2细胞中的表达

目的:构建转基因小鼠模型的载体并检测在人肝癌HepG2中的表达效果.方法:将n-3多不饱和脂肪酸脱氢酶基因fat-1插入到真核表达载体(pcDNA3.1(+)myc-HisA)中,构建重组表达载体pcDNA3.1(+)myc-His A-fat-1,用脂质体介导的方法转染到人肝癌HepG2细胞中,RT-PCR检测fat-l基因的表达,MTT法分析fat-l基因对HepG2细胞增殖的影响,气相色谱分析检测fat-l基因对HepG2细胞n-6/n-3多聚不饱和脂肪酸(PUFAs)比例的影响.结果:成功地构建了真核表达裁体peDNA3.1(+)myc-HisA-fat-1,并能在HepG2细胞内有效异源表达.48h后可检测到fat-l mRMA的条带.与对照细胞相比,fat-l基因有效地抑制了人肝癌细胞HepG2细胞的增殖(70%,p＜0.01),降低了n-6/n-3 PUFAs比例.结论:pcDNA3.1(+)myc-His A-fat-l重组载体构建成功并能在肝癌细胞中有效的表达,可以作为下一步转基因小鼠的合适载体.     

人野生型p53基因增强5-FU对大肠癌化疗敏感性的分子生物学机制

为了探讨人野生型p53（wt-p53）基因增强大肠癌细胞化疗敏感性的分子生物学机制,将携带wt p53基因的质粒分别转染两种p53基因突变的人大肠癌细胞系HT-29及SW620,分析细胞中p53及细胞周期蛋白D1（cyclin D1）蛋白的表达水平;将化疗药物5 氟尿嘧啶（5-fluorouracil,5-FU）以不同浓度、不同时间分别作用于HT-29及SW620细胞,另外将已转染wt-p53基因的大肠癌细胞用5-FU进行诱导,Western印迹分析上述干预条件下细胞中p53蛋白及细胞周期蛋白D1表达水平的变化;流式细胞术检测wt p53基因联合5-FU组及对照组中细胞凋亡的改变情况.结果表明,wt-p53基因能增加癌细胞中细胞周期蛋白D1的表达,与wt-p53基因呈剂量依赖性关系;5-FU则降低其蛋白表达,与5-FU呈时间和剂量依赖性关系,而5-FU所致的细胞周期蛋白D1表达水平的降低在细胞预先转染了wt- p53基因时会被抑制;wt-p53基因与5-FU联合使用能提高大肠癌细胞凋亡率.结果提示,wt-p53基因可提高大肠癌细胞中细胞周期蛋白D1的表达水平,并抑制5-FU所致的细胞周期蛋白D1降解,从而提高大肠癌细胞对化疗药物5-FU的敏感性.     

p53 gene expression of human hepatoma cell lines and their sensitivities to parvovirus H-1]

DNA structure and expression of p53 gene in human hepatoma cell lines SMMC-7721, YY-8103 and a spontaneously transformed liver cell line L-02 were analysed using the following method: analysis of allelic losses on chromosome 17p, PCR/SSCP, Northern blot and immunoprecipitation. There was no point mutation found in the exons 4-9 of the p53 gene, and a low level of expression of p53 gene was detected in the three cell lines. These observations were in agreement to the reported results of the relevant experiment using the human hepatoma cell line QGY-7703. Sensitivities of these cell lines and other eight human hepatoma cell lines (QGY-7703, PLC/PRF/5, Tong/HCC, Huh-7, FOCUS, Hep3B, SK-Hep-1, HepG2) with known p53 backgrounds to parvovirus H-1 was assayed using MTT method. Abnormality in the structure and/or function was observed in all of the cell lines examined except HepG2. The cell line HepG2 with normal structure and function of the p53 gene was found to be the least sensitive to H-1 in comparison to all the cell lines which have defeated structure and/or function of the p53 gene. The present study serves as a preliminary evidence that enhancement of the sensitivity of human hepatoma cell lines to H-1 is correlated to the abnormality of the structure and/or function of the p53 gene.     

Inhibitory effect of parvovirus H—1 on the formation of colonies of human hepatoma cell line in vitro and its tumors in nude mice

The inhibitory effect of parvovirus H-1 on the colonyforming ability.in vitro of QGY-7703,a cultured human hepatoma cell line,and on the formation and growth of its tumors in nude mice was studied.With higher multiplicity of infection(MOI) of H-1 given,survival of the QGY-7703 cells was found to be decreased.H-1 DNA amplification level at 30h postinfection(p.i.) was detected to be 7.4 times higher than that at 2h by dispersed cells assay,while the cells were delayed to enter into S phase.Plaques were formed in the indicator cells(new-born human kidney cell line,NBK) by progeny H-1 virus particles released from the infected QGY-7703 cells by infectious cell center assay.The formation of tumors in nude mice by QGY-7703 cells which were injected s c at 2h postinfection was observed to by prevented in 2 proups with given MOI 25 and 50.The tumor growth of MOI 10 group occurred at a lower exponential rate than that of control,after a 20d latent period.It was evident that parvovirus H-1 exhibited a direct inhibitory effect on the formation and growth of human hepatoma cells in vivo as well as in vitro.     

MKi67-siRNA可抑制QGY-7703细胞的生长

为了探讨MKI67在肝癌细胞发生发展中的作用,采用实时定量 PCR 方法检测人肝细胞癌 QGY 7703 细胞中MKI67 基因表达水平, 以及 MKI67在肝细胞癌组织和癌旁正常组织中的表达情况,设计并合成针对MKI67 的siRNA,利用脂质体转染法将其转入QGY-7703 细胞内,通过MTT和细胞集落形成实验观察MKI67-siRNA 对QGY-7703细胞生长活性和增殖能力的影响.实时定量PCR结果表明,MKI67在肝细胞癌组织中的表达水平明显高于癌旁正常组织（P< 0.01）. MTT和细胞集落形成实验结果显示,转染MKI67-siRNA 的QGY-7703细胞生长活性和集落形成率明显低于对照组（P< 0.01）.由此得出结论：MKI67 在肝癌细胞系QGY-7703细胞中的表达水平较高,且它在肝癌组织中的表达水平明显上调. 同时,MKI67-siRNA 可以有效抑制QGY-7703细胞的生长活性和增殖能力,提示MKI67可能与肝细胞癌的发生、发展相关.     

Some differentiating effects of selenium on the cultured human hepatoma cells and human pulmonary adenocarcinoma cells in vitro

Two human hepatoma cell lines, QGY-7703 and SMMC-7721, and two human pulmonary adenocarcinoma cell lines, LTEP-a-2 and SPC-A-1, were found to respond to 1 μg/mL Na₂SeO₃, 24 h, in-vitro treatment by decreasing its confluent saturation density. The same treatment was found to cause an increase in the adhesiveness of cells measured as resistance to detachment by trypsin/EDTA. The pathological features of tumors after heterotransplantation of treated and untreated cells were similar, but the size of tumor grown from treated cells was much smaller.     

菹草类胡萝卜素提取物对人肝癌细胞QGY-7703凋亡的影响

Human hepatoma cell line QGY-7703 was treated with the medium containing 10, 20, 40 and 60 micromol/L carotenoids extracts from Potamogoton crispus L. (CEPC) for 48 h, 96 h and 144 h, respectively. The inhibition rates to hepatoma cells were determined by MTT assay. The results showed the average inhibition rates of the three treatments varied from 0.14%-23.07%, 39.59%-70.61% and 71.65%-87.01%, respectively. After hepatoma cells were treated with the medium containing 10, 20 and 40 micromol/L of CEPC for 24 h, 48 h and 72 h, respectively, many typical morphology features of apoptotic cells were observed by Laser Scanning Confocal Microscope (LSCM), such as the distinct decrease in number and volume of cells, the shrinkage and deformation of cells, the shape of cell nucleuses appearing like crescent even piece, the decrease in area of yellow DNA in cell nuclei. The percentage of hepatoma cells in every phase of cell cycle was analyzed by Flow Cytometer (FCM) after being treated with 10 micromol/L and 20 micromol/L CEPC for 48 h. Compared with the control group, the cells in G0/G1 phase increased 23.8% (P<0.01) and 35.6% (P<0.01) respectively, in S phase decreased relevantly, while the cells in G2/M phase had no significant change. The Ca2+ concentration (fluorescence intensity) in cytoplasm of hepatoma cells was determined by LSCM after being treated with 20 micromol/L CEPC for 48 h. The Ca2+ concentration increased significantly (P<0.01) and was 1.5 times that of control group. These results demonstrated that the CEPC inhibited the proliferation of hepatoma cells QGY-7703 significantly in a dose and time-dependent manner in vitro. The hepatoma cells treated with CEPC were evidently arrested at G0/G1 phase in the cell cycle. The concentration of Ca2+ in test group cells cytoplasm increased significantly, it might be the important cause that CEPC induced the apoptosis of hepatoma cells QGY-7703. This paper provided scientific basis for further studying and developing the function and value of carotenoids in Potamogoton crispus L.     

Persian shallot, <Emphasis Type="Italic">Allium hirtifolium</Emphasis> Boiss,induced apoptosis in human hepatocellular carcinoma cells

This study investigated the potential of Persian shallot extract as an anticancer agent in HepG2 tumor cell line, an in vitro human hepatoma cancer model system. The inhibitory effect of Persian shallot on the growth of HepG2 cells was measured by MTT assay. To explore the underlying mechanism of cell growth inhibition of Persian shallot, the activity of Persian shallot in inducing apoptosis was investigated through the detection of annexin V signal by flow cytometry and expression of some apoptosis related genes such p21, p53, puma, caspase-8 family-Bcl-2 proteins like bid, bim, bcl-2 and bax were measured by real-time PCR in HepG2 cells. Persian shallot extract inhibited the growth of HepG2 cells in a dose-dependent manner. The IC₅₀ value (inhibiting cell growth by 50%) was 149 μg/ml. The results of real-time PCR revealed a significant up-regulation of bid, bim, caspase-8, puma, p53, p21 and bax genes and a significant downregulation of bcl-2 gene in HepG2 cells treated with Persian shallot extract significantly. Therefore, this is the first report on an increased expression of bid, bim, caspase-8, puma, p53, p21 and bax genes and down regulation of bcl-2 gene indicating that the Persian shallot extract possibly induced the process of cell death through the intrinsic and extrinsic apoptosis pathways and triggers the programmed cell death in HepG2 tumor cell lines by modulating the expression of pro-/anti-apoptotic genes. Furthermore, we showed that Persian shallot extract increased annexin V signal and expression, resulting in apoptotic cell death of HepG2 cells after 24 h treatment. Therefore, according to the results of this study, the Persian shallot extract could be considered as a potential candidate for production of drug for the prevention or treatment of human hepatoma.     

Miscellaneous terpenoid constituents of Abies nephrolepis and their moderate cytotoxic activities

Three monoterpenoids and two triterpenoids were isolated from Abiesnephrolepis together with 53 known terpenoids. The structures of the compounds were established by 1D and 2D NMR spectroscopy. The absolute configuration of 3-hydroxycamphane-2-carboxylic acid was established as (1S,2R,3S,4R) by Cu-Kα X-ray crystallography. All 58 isolates were tested for cytotoxic activity against four tumor cells viz. A549 (human lung adenocarcinoma), Colo205 (colon adenocarcinoma), QGY-7703 (human hepatoma) and THP-1 (human monocytic leukemia). α-Cadinol exhibited the best effects on A549, Colo205 and QGY-7703 with IC₅₀ values of 8.6, 8.1 and 4.6 μg/mL, respectively.     

P-glycoprotein expression induced by glucose depletion enhanced the chemosensitivity in human hepatocellular carcinoma cell-lines

Chemoresistance in cancer cells is frequently associated with an over-expression of the P-glycoprotein (P-gp). The expression of P-gp can be regulated as the cells encounter a number of chemical, physical or environmental stimuli. In this study, P-gp was found gradually expressed in a human hepatocellular carcinoma (HCC) QGY-7703 cells after 48 h of culturing in glucose-free medium. This phenomenon disappeared after the removal of glucose deprivation culture conditions. Mdr1-cDNA isolated from the cell line cultured in glucose-free conditions (namely QGY-7703G), was transiently transformed into the parent QGY-7703 cells, and multi-drug resistance was eventually induced. Results from XTT cytotoxicity assays indicated that the mdr1 gene was functional and the P-gp could restore the QGY-7703 cell's ability to withstand high concentrations of a number of chemotherapeutic agents. A P-gp inhibitor, verapamil, could completely reverse the cellular drug resistance when applied to the QGY-7703G cells. Our results indicated that an alteration of a specific state in cells caused by an external stimulus in vitro may lead to an expression of stress proteins (e.g. P-gp), which may enhance the cells' survival in adverse conditions. The expressed P-gp induced by glucose deprivation has a functional role in affecting the chemosensitivity in HCC QGY-7703G cells. Inhibition of P-gp activity may enhance the effect of the cancer cells towards cancer chemotherapy.     

DNA methylation-regulated miR-193a-3p dictates resistance of hepatocellular carcinoma to 5-fluorouracil via repression of SRSF2 expression

Chemoresistance prevents effective cancer therapy and is rarely predictable prior to treatment, particularly for hepatocellular carcinoma (HCC). Following the chemoresistance profiling of eight HCC cell lines to each of nine chemotherapeutics, two cell lines (QGY-7703 as a sensitive and SMMC-7721 as a resistant cell line to 5-fluorouracil (5-FU) treatment) were systematically studied for mechanistic insights underpinning HCC 5-FU chemoresistance. Genomic profiling at both DNA methylation and microRNA (miR) levels and subsequent mechanistic studies illustrate a new mechanism for how DNA methylation-regulated miR-193a-3p dictates the 5-FU resistance of HCC cells via repression of serine/arginine-rich splicing factor 2 (SRSF2) expression. In turn, SRSF2 preferentially up-regulates the proapoptotic splicing form of caspase 2 (CASP2L) and sensitizes HCC cells to 5-FU. Forced changes of miR-193a-3p level reverse all of the phenotypic features examined, including cell proliferation, cell cycle progression, and 5-FU sensitivity, in cell culture and in nude mice. Importantly, the siRNA-mediated repression of SRSF2 phenocopies all of the miR-193a-3p mimic-triggered changes in QGY-7703. This newly identified miR-193a-3p-SRSF2 axis highlights a new set of companion diagnostics required for optimal 5-FU therapy of HCC, which involve assaying both the DNA methylation state of the miR-193a gene and the expression of miR-193a-3p and SRSF2 and the relative level of the proapoptotic versus antiapoptotic splicing forms of caspase 2 in clinical samples.