槲皮素提高肝癌HepG2细胞热化疗疗效的实验研究

  目的 研究热休克对人肝癌HepG2细胞耐药性的影响，合用槲皮素（Qu）能否提高肝癌细胞热化疗的疗效。方法 42 ℃恒温水浴法热休克传代人肝癌细胞系HepG2细胞90 min。MTT检测半数抑制浓度（IC50），求得耐药倍数、增敏倍数。荧光染色检测凋亡率。流式细胞术检测HSP70和P-gp表达率。结果 Qu能诱导HepG2细胞凋亡。HepG2细胞热休克诱导后4 h对ADM耐药性升高2.78倍（P＜ 0.05），HSP70阳性细胞数升高，4 h达到11.47 ％，升高近1倍（P ＜0.01），P-gp阳性细胞数12 h达到96.31 ％，升高近2倍（P ＜0.01）。热休克前应用Qu能有效抑制热休克诱导HSP70和P-gp的过量表达，抑制细胞对ADM耐药性的产生，起增敏作用（P ＜0.05），呈浓度依赖性。结论 槲皮素可阻断热休克诱导HepG2细胞HSP70和P-gp的过表达，抑制耐药性的产生，起到热化疗的增敏作用，可成为肿瘤耐药逆转剂。     

恩度与阿霉素联用对人肝癌HepG2细胞生长的抑制作用

目的:体外观察恩度与阿霉素联用对人肝癌细胞系HepG2细胞增殖的影响.方法:采用MTT 法观察不同浓度阿霉素、恩度及联合应用对HepG2细胞生长的抑制作用,采用流式细胞仪检测上述药物单独或联合应用对HepG2细胞的凋亡及周期影响.结果:化疗药物单独应用时,对HepG2细胞的抑制作用呈明显的剂量效应依赖关系.阿霉素与恩度均可诱导细胞凋亡,阻滞细胞周期,且联用时有协同作用.结论:恩度与化疗药物联合应用时的具有协同效应.     

稳定表达HBx的HepG2细胞对罗格列酮敏感性的影响及其机制研究

目的：构建稳定表达x基因编码的乙型肝炎病毒x蛋白（x protein of hepatitis B virus，HBx）的HepG2细胞，检测其对罗格列酮敏感性的变化，并探讨HBx与过氧化物酶体增殖物激活受体γ（peroxisome proliferators activated receptor γ，PPARγ）之间的相互作用在原发性肝癌形成过程中的可能机制。方法：构建plRES2-HBx真核表达质粒，筛选稳定表达HBx的HepG2细胞；MTT法检测细胞对罗格列酮的敏感性；免疫细胞化学法检测PPARγ定位的变化；RT—PCR和Western印迹法检测PPART的表达。结果：成功构建pIRES2-HBx真核表达质粒，获得稳定表达HBx的HepG2细胞；罗格列酮对该细胞的抑制作用明显降低（P〈0．05），经丝裂原活化蛋白激酶／细胞外信号调节激酶的激酶1（mitogen-activated protein kinase／extra-cellular signalregulated kinase kinase 1，MEK1）抑制剂PD98059预处理后，抑制率有所回升；PPARγ表达量变化的差异无统计学意义，但在细胞中的表达位置发生改变，即从细胞核转至细胞质。结论：HBx可降低HepG2细胞对罗格列酮的敏感性，可能的机制是HBx可改变PPARγ在细胞内的定位以及与DNA的结合能力．并通过磷酸化狳径影响PPARγ与配体的结合能力及其活性。     

SREBP-1c基因过表达细胞模型的构建及对HepG2细胞脂滴含量的影响

目的：构建SREBP-1c过表达HepG2细胞模型并观察其对脂滴含量的影响,为进一步深入研究肝癌脂滴代谢异常机制提供细胞模型。方法：采用DNA重组技术,将SREBP-1c基因克隆至慢病毒表达载体pLenti 6.3/V5中,并用脂质体介导法将慢病毒包装系统和带目的基因的质粒pLenti6.3-SREBP-1c共转染293T细胞,收集上清,感染HepG2细胞。通过Real-time PCR和Western blot对细胞株进行鉴定。采用免疫荧光检测HepG2细胞中脂滴的数量、大小及细胞内甘油三酯的含量。结果：成功构建了过表达SREBP-1c基因的慢病毒载体pLenti6.3-SREBP-1c,转染后HepG2细胞中可见明显的SREBP-1c蛋白表达。Real-time PCR检测结果显示转染SREBP-1c基因的HepG2细胞中SREBP-1c mRNA水平较对照组升高了约11.4倍。Western blot结果显示SREBP-1c蛋白水平较对照组提高3.2倍。免疫荧光显示过表达SREBP-1c能够明显增加HepG2细胞内脂滴的数量和大小。细胞内甘油三酯定量结果显示甘油三酯含量较对照组明显升高（P < 0.01）。结论：成功构建了SREBP-1c基因过表达的重组慢病毒载体及其稳定转染细胞株。高表达SREBP-1c的HepG2细胞增加了细胞中脂滴的数量、大小和甘油三酯的含量,可用于从脂滴代谢方面对肝癌发病分子机制的研究。     

转录因子XBP1S对人肝癌HepG2细胞增殖及凋亡的影响

目的:探讨人剪接型X盒结合蛋白1(X-box binding protein1spliced,XBP1S)对肝癌HepG2细胞增殖和凋亡的影响。方法:应用衣霉素(tunicamycin,Tm)和毒胡萝卜素(thapsigargin,Tg)建立HepG2细胞的内质网应激(endoplasmic reticulum stress,ERS)模型。将XBP1S真核表达载体pcDNA3.1(-)-XBP1S和靶向XBP1S的RNA干扰质粒pSUPER-XBP1S转染HepG2细胞,MTT法检测细胞的增殖能力,荧光显微镜下观察细胞的形态学变化,FCM法检测细胞凋亡率,Western印迹法检测caspase12的表达。结果:转染pSUPER-XBP1S可有效抑制细胞增殖,而转染pcDNA3.1(-)-XBP1S可促进细胞增殖。荧光显微镜下可见Tm处理组细胞出现细胞凋亡的形态学改变,进一步下调XBP1S的表达可使这一改变增强。对照组、Tm组、Tm+pSUPER-XBP1S转染组和Tm+pcDNA3.1(-)-XBP1S转染组细胞的凋亡率分别为5.21%、41.51%、52.15%和35.87%,差异有统计学意义(P<0.05)。HepG2细胞中caspase12的表达,Tm组高于对照组,Tm+pSUPER-XBP1S转染组高于Tm组,Tm+pcDNA3.1(-)-XBP1S转染组低于Tm组。结论:XBP1S可以促进肝癌HepG2细胞增殖,抑制或促进XBP1S表达可调节ERS介导的细胞凋亡。     

热休克诱导人肝癌HepG2细胞HSP70和P-gp的表达及槲皮素对二者的抑制作用

背景与目的:研究提示热休克蛋白70(heatshockprotein70,HSP70)可抑制细胞凋亡,降低肿瘤热疗、化疗的疗效,但其与细胞化疗耐受性的内在关系尚不甚明确;P-糖蛋白(P-glycoprotein,P-gp)是一种耐药蛋白,在肿瘤耐药中起重要作用。本研究拟通过热休克诱导人肝癌HepG2细胞表达HSP70和P-gp,并观察槲皮素(quercetin,Qu)对二者表达的抑制效应。方法:恒温水浴法,42℃热休克HepG2细胞90min,分别采用免疫组化、流式细胞术检测热休克前及热休克后2h、4h、8h、12h、24h时HSP70和P-gp的表达情况;并于热休克前1h应用不同浓度槲皮素作用于HepG2细胞,观察其热休克后4h二者的表达。结果:(1)热休克诱导后,免疫组化显示细胞内HSP70表达增多,“核内迁移”;流式细胞术示HSP70阳性细胞数升高,4h达到最高(11.47%),较对照组(6.64%)升高近一倍(P<0.01),24h后回落到低值;P-gp阳性细胞数随HSP70升高后升高,12h达到最高值(96.31%),较对照组(33.95%)升高近两倍(P<0.01),24h后回落到低值。(2)热休克前应用槲皮素能有效抑制热休克诱导HSP70和P-gp的过量表达,以100～200μmol/L槲皮素作用明显(P<0.01),呈浓度依赖性。结论:热休克可诱导HepG2细胞HSP70和P-gp的过量表达,P-gp的表达可能与HSP70的表达有关;槲皮素可阻断热休克诱导HepG2细胞HSP7     

FAT10过表达对HepG2肝癌细胞生长及凋亡的影响

目的:探讨FAT10过表达对人肝癌细胞株HepG2生长和凋亡的影响。方法:采用脂质体法将FAT10质粒导入HepG2细胞,建立FAT10过表达的肝癌细胞系。Western blot检测细胞中FAT10表达水平,CCK-8细胞计数试剂盒,Annexin V凋亡试剂盒检测FAT10过表达对HepG2细胞生长和凋亡的影响。人类基因表达谱芯片检测FAT10下游与细胞增殖和凋亡相关基因的差异表达。结果:Western blot结果显示FAT10过表达细胞FAT10蛋白水平明显高于对照组,CCK-8检测显示FAT10过表达细胞增殖速度高于空载体组和对照组,而抗喜树碱诱导凋亡的能力FAT10过表达组较空载体组和对照组强。芯片分析显示,FAT10下游与细胞增殖和凋亡相关的若干基因表达有显著差异。结论:FAT10过表达可以促进HepG2细胞增殖和抗凋亡能力。     

稳定转染HBx基因的HepG2细胞株的建立及其对p53-p21途径的影响

目的 将构建的乙型肝炎病毒X基因的真核表达载体稳定转染HepG2细胞株, 并研究转染后对p53-p21途径的影响。 方法 用基因转染的方法将已构建的载体pcDNA3.1-HBx 转染入肝癌细胞HepG2中, G418筛选出稳定转染X基因的细胞株。细胞生长曲线、平板克隆形成实验检测转染后肝癌细胞的恶性表型,流式细胞仪检测细胞凋亡和周期,Western blot检测p53蛋白的表达,RT-PCR检测p21基因。结果 成功筛选出pcDNA3.1-HBx稳定转染的HepG2细胞株;细胞生长实验、平板克隆形成实验显示稳定转染乙型肝炎病毒X基因的肝癌细胞恶性表型增高;流式细胞仪结果显示,转染后的细胞株凋亡率增高,G₁/G₀期细胞减少,G₂期细胞增多;Western blot 和RT-PCR分别显示,转染株p53蛋白表达增高,且下调p21基因水平。 结论 乙型肝炎病毒X蛋白可刺激肝癌细胞生长, 稳定转染X基因的细胞株可能通过p53-p21途径增加肝癌细胞的恶性表型。     

三氧化二砷与肿瘤坏死因子联合对人肝癌细胞系HepG2抑制作用的研究

近年来，国内外对砷剂与肿瘤的研究发展很快。已有研究表明，三氧化二砷(As2O3)可在体外抑制肝癌细胞的增殖，且主要是通过其诱导凋亡作用实现的。但尚未有As2O3和TNF-α联合作用于肿瘤细胞的报道。为减弱砷剂毒性，并充分利用FNF-α的诱导凋亡作用。我们将二者联合应用，观察它们对肝癌细胞HepG2的影响及作用机制。     

乙肝病毒x基因转染对奥曲肽抑制肝癌细胞HepG2生长的影响

背景与目的:体外及动物实验表明,生长抑素类似物奥曲肽可抑制肝癌生长,但奥曲肽治疗肝癌的临床疗效并不满意,原因不明。本研究拟探讨有乙型肝炎病毒感染的肝癌是否因其有x基因而改变了对奥曲肽作用的反应及其可能的机制。方法:采用3H鄄TdR掺入法了解细胞DNA合成,细胞免疫化学检测细胞的PCNA表达,AnnexinⅤ荧光标记法及TUNEL法观察细胞的凋亡,Westernblot法检测HepG2和HepG2x细胞ERK及生长抑素受体(somatostatinreceptors,SSTR)的表达。结果:1×10-5～1×10-9mol/L的奥曲肽显著地、浓度依赖性地抑制HepG2细胞3H鄄TdR掺入及PCNA表达(r=-0.917,P<0.01)。奥曲肽也促进HepG2细胞凋亡,其AnnexinⅤ的阳性率为(14.20±2.57)%,对照组仅为(1.18±0.13)%,两组间差异有显著性(P<0.05);TUNEL检测奥曲肽组凋亡指数为(18.8±3.3)%,对照组仅为(3.6±0.9)%,两组间差异有显著性(P<0.05)。奥曲肽及奥曲肽加拉米夫定对HepG2x细胞抑制生长和诱导凋亡作用不明显。HepG2x细胞的SSTR鄄2和SSTR鄄5表达均明显低于HepG2细胞(P<0.01);HepG2x细胞的细胞外信号调节激酶鄄1(extracellularsignal鄄regulatedkinase鄄1,ERK鄄1)和ERK鄄2表达均显著高于HepG2细胞(P<0.05)。奥曲肽未明显改变HepG2x细胞的ERKs表达。结论:转染x基因后的HepG2细胞SSTR鄄2及SSTR鄄5明显下调,导致奥曲肽对HepG2x细胞的生长抑制作用明显降低。     

Hepatitis B virus X protein upregulates expression of SMYD3 and C-MYC in HepG2 cells

The carcinogenic role of Hepatitis B X (HBX) in hepatocellular carcinoma (HCC) remains largely unknown. Histone H3 lysine 4 methyltransferase SMYD3 was found to be over-expressed and have a pro-carcinogenic effect in HCC. The role of HBX in regulating SMYD3 activity and the corresponding C-MYC gene in HCC carcinogenesis was investigated. SMYD3 and C-MYC expression in HBV-negative HepG2 and HBV-positive HepG2.2.15 were detected by real time PCR and Western blot. After transfection of HBX into HepG2, SMYD3 and C-MYC protein expression was detected and the apoptosis and proliferation of hepatoma cells were assayed. After SMYD3 expression in HepG2 with HBX transfection downregulated by siRNA, the corresponding C-MYC expression, cellular apoptosis, and proliferation were assayed by FACS. SMYD3 mRNA and protein and C-MYC protein were significantly higher in HepG2.2.15 than in HepG2. HBX transfection resulted in enhanced SMYD3 and C-MYC expressions, decreased cell apoptosis, and increased cell proliferation in HepG2 cells. Knocking down of SMYD3 in HepG2 with HBX transfection inhibited C-MYC expression and promoted apoptosis. These results suggest that HBX upregulates SMYD3 expression in HepG2, which may promote hepatoma development and progress. C-MYC may act as a down-stream gene in HBX-SMYD3-related hepatocarcinogenesis.     

Hepatitis B virus X protein mutant upregulates CENP-A expression in hepatoma cells

The carcinogenic role of hepatitis B virus x protein (HBx) in hepatocellular carcinoma (HCC) remains largely unknown. Centromere protein A (CENP-A) has been found to be frequently overexpressed in HCC. In the present study, we aimed to investigate the role of HBx in regulating CENP-A activity in HCC carcinogenesis. CENP-A expression was examined and the HBx gene was sequenced in 20?HBsAg-positive HCC patients and corresponding non-cancerous liver tissues. The influence of HBx mutants on CENP-A expression in HepG2 cells was analyzed by a series of assays. We found that CENP-A expression was significantly elevated in HCC tissues. HBx deletion, especially the COOH-terminal deletion of HBx is a frequent event in HBV-associated HCC tissues. A positive correlation was found between CENP-A expression and HBx COOH mutation in HCC tissues. HBx mutant increased the expression of the CENP-A mRNA and protein compared with full-length HBx. However, HBx did not directly interact with CENP-A. It is concluded that overexpression of CENP-A is closely associated with HBx COOH mutation in HCC. HBx mutant can increase CENP-A expression, probably through a mechanism independent of their physical combination, and thereby it may represent a potential therapeutic strategy for HCC.     

Diverse regulations of albumin gene expression by hepatocyte growth factor in HepG2 human hepatoma cells and primary culture of rat hepatocytes

The effects of HGF on albumin gene expression in HepG2 human hepatoma cells and rat hepatocytes were investigated. HGF reduced the levels of albumin mRNA in HepG2 cells but the level was augmented in rat hepatocytes. By the transfection assay, HGF stimulated albumin promoter activity but repressed alpha-fetoprotein (AFP) enhancer activity regulating both AFP and albumin promoters in HepG2 cells. In contrast, HGF stimulated albumin promoter and AFP enhancer activities in rat hepatocytes. These results suggest that HGF elicits diverse responses of albumin gene expression in HepG2 cells and rat hepatocytes through the different biological actions on AFP enhancer in these cells.     

MST-312对人肝癌HepG2细胞辐射敏感性影响研究

目的研究端粒酶抑制剂MST-312对人肝癌细胞HepG2辐射敏感性影响。方法 MTT实验检测0、2、4、6、8和10μmol/L的MST-312对HepG2细胞的增殖抑制作用;采用克隆形成实验检测HepG2细胞存活率,观察MST-312对细胞辐射增敏性的影响;流式细胞术分析细胞周期及凋亡率;Hoechst 33258荧光染色法检测细胞凋亡的形态变化;蛋白质印迹法检测γ-H2AX蛋白表达水平,衡量DNA损伤的程度。结果 MTT法检测结果显示,MST-312对HepG2细胞增殖抑制作用呈剂量依赖性,4μmol/L MST-312对HepG2细胞的增殖抑制率<10%,而且对细胞的周期分布没有明显影响。克隆形成实验结果显示,MST-312预处理2h后再给予X射线辐照的联合组克隆形成率为(17.68±4.01)%,较辐照组(62.60±7.91)%明显降低,F=9.773,P=0.014。流式细胞术分析结果表明,随着时间的延长,联合组G2/M期的比例由(20.56±0.75)%下降至(5.82±0.45)%,而Sub-G1峰值由(6.13±0.43)%上升至(15.78±0.89)%,即随着G2/M期阻滞比例下降的同时Sub-G1峰值比例在上升。Hoechst 33258荧光染色结果表明,在X射线处理后12h,联合组比辐照组出现了更加明显的细胞凋亡形态变化。蛋白质印迹法检测结果显示,在辐照后24h,联合组γ-H2AX蛋白表达量(614.20±21.13)%,高于辐照组(421.78±19.11)%,F=14.513,P=0.005。提示DNA损伤严重,未完全修复。结论端粒酶抑制剂MST-312促进了辐射诱导的细胞凋亡,对HepG2细胞具有辐射增敏作用,其机制可能与加剧辐射诱导的端粒损伤和抑制辐射后DNA损伤修复有关。     

TSLC1基因真核表达载体的构建及在HepG2细胞中的表达

Objective： To construct the eukaryotic expression vector for human TSLC1 gene, and to express TSLC1 in HepG2 cells for investigating its effect on HepG2 cell growth. Methods： Full length of TSLC1 cDNA was amplified from RNA of normal human liver by RT-PCR, and cloned into pCI-neo expression vector. The recombinant plasmid pCI-TSLC1 was identified with restriction enzyme and sequenced, and then was stably transfected into HepG2 cells with lipofectamine 2000. The positive clones were examined by western-blotting and immunofluorescence, cell growth was analyzed with MTT assay. Results： The eukaryotic expression vector pCI-TSLC1 was successfully constructed and the stable cell line highly expressing TSLC1 protein was obtained. The growth of TSLCl-transfected cells was significantly suppressed in vitro. Conclusion： The HepG2 stable cell line could highly express TSLC1 protein, which provided a basis for further exploring the roles of TSLC1 in hepatocellular carcinoma.     

NOR1基因对HepG 2细胞E-选择素的影响

目的：探讨NOR1基因对HepG2细胞E-选择素的影响。方法：将NOR1基因通过脂质体转染HepG2细胞后，抽提细胞总RNA，采用RT-PCR法检测HepG2细胞中NOR1基因和E-选择素mRNA的表达水平；ELISA法检测细胞培养上清液中E-选择素的蛋白表达水平。结果：RT-PCR结果显示，转染NOR1基因组E-选择素mRNA的表达水平明显高于空白组和对照组的E-选择素mRNA的表达水平（P〈0．01）。ELISA结果显示，转染NOR1基因组E-选择素蛋白水平明显高于空白组和对照组（P〈0．01）。结论：NOR1基因可诱导HepG2细胞中E-选择素表达水平的增高。