5-氮杂-2′-脱氧胞苷对肝癌细胞HepG2凋亡及其PEG10基因表达的影响

目的探讨去甲基化药物5-氮杂-2′-脱氧胞苷（5-Aza-CdR）对人肝癌细胞系HepG2凋亡及其PEG10基因表达调控的影响,进一步探讨肝癌的发病机制及5-Aza-CdR治疗肝癌的可行性。方法用浓度为50 μmol/L的5-Aza-CdR分别处理HepG2细胞24、48、72 h,hoechst 33342/PI 双染荧光显微镜检测HepG2细胞凋亡情况。RT-PCR、Western blot法分别检测PEG10 mRNA和蛋白表达水平的变化。结果与对照组相比,5-Aza-CdR作用24、48、72 h后,HepG2细胞的凋亡率明显升高,PEG10 mRNA 和蛋白表达水平显著下降,并呈现时间依赖性（P＜0.05）。结论5-Aza-CdR 可促进HepG2细胞凋亡并抑制PEG10基因的表达。     

5-脂氧合酶抑制剂对人肝癌细胞株HepG2增殖和凋亡的影响

目的：研究5-脂氧合酶（5-lipoxygenase,5-Lox）在人肝癌细胞株HepG2中的表达,以及5-Lox抑制剂对人肝癌细胞株HepG2增殖、凋亡的影响。方法：应用免疫细胞化学染色及RT-PCR分别检测5-Lox的蛋白和mRNA在人肝癌细胞株HepG2中的表达,采用MTT法及流式细胞术检测5-Lox抑制剂齐留通（Zileuton）对人肝癌细胞株HepG2增殖、凋亡的影响。结果：5-Lox蛋白表达于肝癌细胞浆,局灶细胞核膜亦见阳性染色,RT-PCR可检测到肝癌细胞5-Lox的mRNA的表达。人肝癌细胞株HepG2给予不同浓度的齐留通处理24小时后,细胞存活率呈剂量依赖性下降;流式细胞术检测可见细胞凋亡率呈剂量依赖性升高。结论：人肝癌细胞株HepG2存在5-Lox的表达,5-Lox抑制剂齐留通可抑制人肝癌细胞株HepG2的增殖,诱导细胞凋亡。     

5-脂氧合酶抑制剂对人肝癌细胞株HepG2增殖和凋亡的影响

目的:研究5-脂氧合酶(5-lipoxygenase,5-Lox)在人肝癌细胞株HepG2中的表达,以及5-Lox抑制剂对人肝癌细胞株HepG2增殖、凋亡的影响。方法:应用免疫细胞化学染色及RT-PCR分别检测5-Lox的蛋白和mRNA在人肝癌细胞株HepG2中的表达,采用MTT法及流式细胞术检测5-Lox抑制剂齐留通(Zileuton)对人肝癌细胞株HepG2增殖、凋亡的影响。结果:5-Lox蛋白表达于肝癌细胞浆,局灶细胞核膜亦见阳性染色,RT-PCR可检测到肝癌细胞5-Lox的mRNA的表达。人肝癌细胞株HepG2给予不同浓度的齐留通处理24小时后,细胞存活率呈剂量依赖性下降;流式细胞术检测可见细胞凋亡率呈剂量依赖性升高。结论:人肝癌细胞株HepG2存在5-Lox的表达,5-Lox抑制剂齐留通可抑制人肝癌细胞株HepG2的增殖,诱导细胞凋亡。     

5-氮杂-2′-脱氧胞苷对非小细胞肺癌体外生长及侵袭能力和TFPI-2基因mRNA表达的影响

目的 探讨5-氮杂-2′-脱氧胞苷(5-aza-2-deoxycytidine,5-Aza-CdR)干预对非小细胞肺癌(nonsmallcell non cancer, NSCLC)细胞株A549生长增殖及其组织因子途径抑制物2(tissue factor pathwayinhibitor-2,TFPI-2)基因表达的影响,同时探讨5-Aza-CdR能否通过恢复TFPI-2基因表达抑制非小细胞肺癌A549细胞侵袭能力。方法 用不同浓度的5-Aza-CdR处理A549细胞株,MTT法检测药物处理24、48、72 h后的细胞增殖活性,流式细胞仪(fl ow cytometry, FCM)法检测药物处理72 h后细胞周期分布,Real-time PCR技术检测药物处理72h后A549细胞TFPI-2基因mRNA的表达,Transwell小室法测定药物处理24h后A549细胞体外侵袭能力的变化。 结果 MTT检测显示不同浓度5-Aza-CdR处理A549细胞24、48、72h后,细胞的生长受到抑制,且抑制作用呈明显的剂量和时间依赖性。FCM检测分析显示0、1、5、10 μM 5-Aza-CdR处理A549细胞72 h 后,细胞增殖指数逐渐降低,分别为（30.43±0.99)%、（23.89±0.83)%、（16.19±0.34)%、（6.49±0.55%（P＜0.05）。Real-timePCR检测显示0、1、5、10 μM的5-Aza-CdR处理A549细胞72 h后,相对mRNA表达水平分别为（1±0)、（1.49±0.14)、（1.86±0.09)、（5.80±0.15)（P<0.05）,TFPI-2 基因mRNA表达呈明显的上升趋势,且随着药物浓度增加而增加。Transwell小室法检测显示每一高倍镜下平均穿膜细胞数分别为（316.15±18.7)、（84.15±12.14)、（28.85±7.13)、（14.35±3.33),均明显低于对照细胞（P<0.05）。结论 5-Aza-CdR能通过降低TFPI-2基因的甲基化而恢复其在非小细胞肺癌细胞株A549细胞中的表达,并抑制A549细胞的增殖和侵袭。     

水蛭素对肝细胞癌HepG2细胞抑制作用机制探讨

目的 研究水蛭素对肝细胞癌（hepatocellular carcinoma,HCC,简称肝癌）HepG2细胞抑制作用及其抗肝癌的分子机制。方法 将含不同浓度（1 U/mL、2 U/mL、4 U/mL和8 U/mL）水蛭素的培养液作用于肝癌HepG2细胞,采用MTT法检测水蛭素对肝癌HepG2细胞增殖的影响,流式细胞仪检测水蛭素对肝癌HepG2细胞凋亡的影响,Transwell法检测水蛭素对肝癌HepG2细胞迁移、侵袭的影响,荧光定量PCR检测血管内皮生长因子（vascular endothelial growth factor,VEGF）基因的mRNA表达水平,Western blot检测VEGF基因的蛋白表达水平。结果 与空白对照组比较,肝癌HepG2细胞增殖抑制率随水蛭素浓度（1 U/mL、2　U/mL、4 U/mL和8 U/mL）增加及作用时间（24　h、48　h、72　h）延长而增加,呈剂量-时间依赖效应（P<0.05）。不同浓度（2 U/mL、4 U/mL和8 U/mL）水蛭素作用48 h后,肝癌HepG2细胞凋亡率分别为（28.37±1.16）%、（40.27±0.97）%、（76.17±1.5）%,细胞侵袭个数分别为（204±9）个、（163±6）个、（94±4）个,细胞迁移个数分别为（86±5）个、（54±7）个、（20±5）个,细胞凋亡率、侵袭及迁移个数随水蛭素浓度增加而增加,呈浓度依赖性（P<0.05）。VEGF mRNA、蛋白的表达量随水蛭素浓度增加而明显下调（P<0.05）。结论 水蛭素能抑制肝癌HepG2细胞增殖、凋亡、迁移及侵袭,其机制可能是通过下调VEGF表达。     

5-Aza-CdR对人喉鳞癌Hep2细胞凋亡及蛋白质表达的影响

目的:探讨5-Aza-CdR对人喉鳞癌Hep2细胞凋亡及蛋白质表达的影响。方法:Hep2细胞分别经10-7mol/L 5-Aza-CdR和DMSO处理72h,应用Hoechst33258染色及流式细胞仪检测5-Aza-CdR对Hep2细胞凋亡的影响。抽提各组Hep2细胞总蛋白质,行双向电泳,采用PDQuest-7.0.1软件及MALDI-TOF质谱技术筛查5-Aza-CdR对Hep2细胞蛋白表达的影响,并通过Western blot对显著性差异蛋白质进行验证。结果:人喉鳞癌Hep2细胞在10-7mol/L 5-Aza-CdR处理72h后出现明显的细胞核致密浓染,Hep2细胞的凋亡率由对照组的(2.70±0.28)%增加到(13.96±0.41)%,具有统计学意义(P<0.05)。双向电泳筛查了包括S100A4在内的5种表达显著差异的蛋白质,Western blot进一步验证了5-Aza-CdR能明显上调喉鳞癌Hep2细胞中S100A4的表达,进而证明了双向电泳结果的可信性。结论:5-Aza-CdR介导的Hep2细胞部分蛋白质表达改变,直接或间接地参与了5-Aza-CdR诱导的Hep2细胞凋亡的发生,为5-Aza-CdR在喉鳞癌探讨性治疗中的机制研究奠定基础。     

番茄红素对人肝癌HepG2细胞增殖和凋亡的影响

目的 研究番茄红素(Lycopene,LP)对人肝癌HepG2细胞生长的影响并初探其机制。方法取对数生长期HepG2细胞设空白对照组、LP(5 μg/mL)组、LP(10 μg/mL)组、LP(20 μg/mL)组和顺铂(40 μg/mL)组,每组设10个复孔;各组分别给药干预48 h后,噻唑蓝(MTT)比色法测定细胞增殖抑制率,流式细胞术(FCM)检测细胞周期和细胞凋亡状况,RT-PCR法检测Bax mRNA和Bcl-2 mRNA表达,Western blot法检测Caspase-3蛋白表达。结果 与空白对照组比较,经LP(10 μg/mL、20 μg/mL)或顺铂40 μg/mL干预48 h能够显著提高HepG2细胞增殖抑制率,延长细胞周期中G₀/G₁期而缩短G₂/M期,提高细胞凋亡率,上调促凋亡Bax mRNA表达并下调抑凋亡Bcl-2 mRNA表达,提高Bax/Bcl-2比值,上调Caspase-3蛋白表达,LP上述作用具有一定的剂量依赖性。结论 LP具有抑制人肝癌HepG2细胞增殖并促进其凋亡的作用,其机制可能与LP干预细胞周期分布和调节凋亡相关基因蛋白表达有关。     

胰岛素抵抗的人肝癌细胞HepG2对多柔比星的敏感性

目的:观察胰岛素抵抗(insulin resistance, IR)的人肝癌细胞对抗癌药物多柔比星(adriamycin,ADM)的敏感性,并探讨其抗药机制.方法:采用5×10-6 moL/L胰岛素诱导(36和48 h)人肝癌细胞HepG2建立HepG2/IR细胞模型,并用盐酸吡格列酮(pioglitazone hydrochloride, PH)逆转HepG2/IR细胞的IR状态.MTT法检测HepG2/IR细胞对ADM的敏感性,FCM检测P糖蛋白(P-glycoprotein, P-gp)的表达水平,实时荧光定量RT-PCR检测多药耐药基因1(multiple drug resistance 1, MDR1)mRNA的表达.结果:HepG2/IR细胞对ADM的敏感性降低(P<0.05),MDR1 mRNA的表达量分别是HepG2细胞的1.62倍(胰岛素诱导36 h)和5.21倍(胰岛素诱导48 h),P-gp蛋白的阳性表达率分别提高了47.50%(胰岛素诱导36 h)和189.05%(胰岛素诱导48 h).PH可逆转HepG2/IR细胞MDR1/P-gp的表达增加以及逆转细胞对ADM的抗药性.结论:胰岛素诱导的人肝癌细胞HepG2/IR可通过增加MDR1/P-gp的表达,使细胞对抗癌药物产生抗药性.     

5-Aza-CdR对人喉鳞癌Hep2细胞凋亡及蛋白质表达的影响

目的：探讨5-Aza-CdR对人喉鳞癌Hep2细胞凋亡及蛋白质表达的影响。方法：Hep2细胞分别经10^-7mol/L 5-Aza-CdR和DMSO处理72h,应用Hoechst33258染色及流式细胞仪检测5-Aza-CdR对Hep2细胞凋亡的影响。抽提各组Hep2细胞总蛋白质,行双向电泳,采用PDQuest-7.0.1软件及MALDI-TOF质谱技术筛查5-Aza-CdR对Hep2细胞蛋白表达的影响,并通过Western blot对显著性差异蛋白质进行验证。结果：人喉鳞癌Hep2细胞在10-7mol/L 5-Aza-CdR处理72h后出现明显的细胞核致密浓染,Hep2细胞的凋亡率由对照组的（2.70±0.28）%增加到（13.96±0.41）%,具有统计学意义（P〈0.05）。双向电泳筛查了包括S100A4在内的5种表达显著差异的蛋白质,Western blot进一步验证了5-Aza-CdR能明显上调喉鳞癌Hep2细胞中S100A4的表达,进而证明了双向电泳结果的可信性。结论：5-Aza-CdR介导的Hep2细胞部分蛋白质表达改变,直接或间接地参与了5-Aza-CdR诱导的Hep2细胞凋亡的发生,为5-Aza-CdR在喉鳞癌探讨性治疗中的机制研究奠定基础。     

竹节香附素A对HepG2细胞缺氧诱导因子-1α基因和蛋白表达的影响

目的:探讨竹节香附素A对缺氧条件下人肝癌细胞株(HepG2)细胞缺氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)基因和蛋白表达的影响.方法:取体外低氧环境下HepG2细胞进行不同干预:特定浓度(10 μg/ml)竹节香附素A不同作用时间(0 h、6 h、12 h、24 h);不同浓度(0、5、10、20 μg/ml)竹节香附素A特定作用时间(24 h)处理,通过半定量逆转录-聚合酶链反应(RT-PCR)和Western blot检测HepG2细胞HIF-1α mRNA和蛋白的表达变化情况.结果:体外低氧环境下HepG2细胞可见HIF-1α mRNA和蛋白强表达,特定浓度(10 μg/ml)竹节香附素A可显著抑制HIF-1α mRNA和蛋白的表达水平,药物作用0 h、6 h、12 h、24 h时HIF-1α mRNA 条带灰度值(A/A0)分别为0.73±0.08、0.44±0.12、0.24±0.09、0.07±0.03,差异具有统计学意义(P<0.01);HIF-1α蛋白A/A0比值分别为2.31±0.33、1.70±0.17、1.30±0.96、0.09±0.13,差异具有统计学意义(P<0.01).不同浓度竹节香附素A特定作用时间(24 h)处理可显著抑制HIF-1α mRNA和蛋白的表达水平,药物浓度0、5、10、20 μg/ml处理,HIF-1α mRNA A/A0比值分别为0.65±0.07、0.43±0.08、0.19±0.03、0.08±0.02,差异具有统计学意义(P<0.01);HIF-1α蛋白A/A0比值分别为0.84±0.08、0.39±0.06、0.28±0.04、0.08±0.03,差异具有统计学意义(P<0.01).结论:竹节香附素A对缺氧条件下肝癌HepG2细胞HIF-1α mRNA和蛋白的表达具有抑制作用,并存在时间-剂量依赖性效应.     

Antitumor activity of 2'-deoxy-2'-methylidenecytidine, a new 2'-deoxycytidine derivative

The antitumor activity of 2'-deoxy-2'-methylidenecytidine (DMDC), an inhibitor of DNA synthesis, was examined and compared with that of 1-beta-D-arabinofuranosylcytosine (ara-C) against various murine tumors and human tumor xenografts. Against P388 murine leukemia, repeated treatments of DMDC were more effective than its single administration. Interestingly, DMDC was effective against colon 26 murine carcinoma, M5076 murine reticulum cell sarcoma, LX-1 human lung cancer xenograft, and SK-Mel-28 human melanoma xenograft, which are less sensitive or refractory to ara-C, while DMDC was not more potent against murine leukemias P388 and L1210 than ara-C. The in vitro cytotoxic effects of DMDC and ara-C against L1210 leukemia cells were prevented dose dependently by deoxycytidine, suggesting that DMDC, like ara-C, may require phosphorylation by deoxycytidine kinase for antitumor activity. DMDC was effective against human and murine experimental tumor models, especially nonleukemic tumors refractory to ara-C, suggesting that DMDC will be a promising agent for the treatment of cancer.     

转染和干扰Runx2基因对K7M2细胞的影响

 目的探讨干扰和转染Runx2基因后对K7M2骨肉瘤细胞体外生物学活性的影响。方法分别将阴性对照质粒、携带Runx2和siRNA Runx2的质粒转染到K7M2细胞中。应用Western blot检测转染和干扰Runx2基因对其蛋白表达的影响,并检测细胞体外的增殖能力(MTT )、侵袭性、迁移性和黏附性的变化,并应用流式细胞仪（FCM）检测相应细胞的凋亡率和细胞周期分布的变化。结果与空白对照组比,转染Runx2和siRunx2组的K7M2细胞中Runx2蛋白表达分别明显增强和减弱,而阴性对照质粒组没有明显改变。转染siRunx2组的细胞,MTT结果显示增殖能力明显下降,迁移性、侵袭性和增殖指数（PI）也明显下降,与空白对照组比差异有统计学意义（P<0.05）,黏附性和凋亡率却没有明显变化。转染Runx2组K7M2的细胞增殖能力、迁移性、侵袭性和PI明显增高,与空白对照组比差异有统计学意义（P<0.05）,黏附性和凋亡率没有明显变化。阴性对照组和空白对照组比上述指标没有明显改变。结论Runx2可以促进K7M2细胞增殖,增强细胞的侵袭、迁移能力,其机制可能是和改变细胞周期的分布,使细胞更快的进入G₂/M期有关。     

Identification of CYP2C9*2 Allele in HepG2 Cell Line

Background

Hepatoma is caused by many factors including alcohol, chemicals, viral infection, and chronic inflammation. Cytochrome P450 polymorphism plays an important role in its pathogenesis. CYP2D6, CYP2E1, and CYP1A1 have been identified to be related with hepatic carcinogenesis and tumor size and stage. However, no studies have been performed on CYP2C9, a major CYP in the liver and hepatoma.

Aim of the study

To identify if there is polymorphism of CYP2C9 in a HepG2 cell line.

Methods

A pair of primers was used to clone CYP2C9 exon 3 region and subsequently sequenced. The sequence was compared to normal CYP2C9 for identification of any mutation.

Results

A point mutation was identified. It was located in the amino acid number 144 of CYP2C9 protein with the change of normal amino acid arginine into cysteine, which is the same as identified in poor metabolism patients as homozygous CYP2C9*2.

Conclusions

There is a mutation (CYP2C9*2/ CYP2C9*2) in a HepG2 cell line. Thus, polymorphism of CYP2C9 may also be involved in the carcinogenesis of hepatoma as CYPs2D6 and 2E1.     

Cyclooxygenase-2 (COX-2)-independent anticarcinogenic effects of selective COX-2 inhibitors

Nonsteroidal antiinflammatory drugs (NSAIDs) appear to reduce the risk of developing cancer. One mechanism through which NSAIDs act to reduce carcinogenesis is to inhibit the activity of cyclooxygenase-2 (COX-2), an enzyme that is overexpressed in various cancer tissues. Overexpression of COX-2 increases cell proliferation and inhibits apoptosis. However, selective COX-2 inhibitors can also act through COX-independent mechanisms. In this review, we describe the COX-2-independent molecular targets of these COX-2 inhibitors and discuss how these targets may be involved in the anticarcinogenic activities of these selective COX-2 inhibitors. We also compare the concentrations of these inhibitors used in in vitro and in vivo experiments and discuss the implications of the in vitro studies for clinical management of cancer with these drugs.     

Evaluation of the antitumor activity of gemcitabine (2',2'-difluoro-2'-deoxycytidine)

A new pyrimidine antimetabolite, 2',2'-difluorodeoxycytidine, Gemcitabine (LY188011, dFdCyd) has been synthesized and evaluated in experimental tumor models. dFdCyd is a very potent and specific deoxycytidine analogue. The concentration required for 50% inhibition of growth is 1 ng/ml in the CCRF-CEM human leukemia cell culture assay. Concurrent addition of deoxycytidine to the cell culture system provides about a 1000-fold decrease in biological activity. The inhibition of growth of human leukemia cells in culture led to the in vivo evaluation of this compound as a potential oncolytic agent. Maximal activity in vivo was seen with dFdCyd when administered on an every third day schedule. 1-beta-D-Arabinofuranosylcytosine, administered on a daily for 10-day schedule, was directly compared to dFdCyd in this evaluation. dFdCyd demonstrated good to excellent antitumor activity in eight of the eight murine tumor models evaluated. 1-beta-D-Arabinofuranosylcytosine was substantially less active or had no activity in these same tumor models. This in vivo activity against murine solid tumors supports the conclusion that dFdCyd is an excellent candidate for clinical trials in the treatment of cancer.     

Cell cycle-dependent phosphorylation of Disabled-2 by cdc2

Disabled-2 (Dab2; also known as p96 and DOC-2) is a signal transduction protein that has been implicated in the control of cell growth. Dab2 is known to be a phosphoprotein, but little is known about the kinases that phosphorylate Dab2. We have found that Dab2 phosphorylation is markedly increased during the mitosis phase of the cell cycle. This phosphorylation is blocked by roscovitine, a selective inhibitor of cyclin-dependent kinases. Dab2 robustly coimmunoprecipitates from cells with the cyclin-dependent kinase cdc2, and purified cdc2 can phosphorylate purified Dab2 fusion proteins in vitro on multiple sites. Cellular phosphorylation of Dab2 by cdc2 promotes the association of Dab2 with Pin1, a peptidylprolyl isomerase that regulates the rate of Dab2 dephosphorylation. These findings reveal that Dab2 is differentially phosphorylated during the cell cycle by cdc2 and provide a potential feedback mechanism by which Dab2 inhibition of cell growth and proliferation may be regulated.     

Polymorphisms in prostaglandin synthase 2/cyclooxygenase 2 (PTGS2/COX2) and risk of colorectal cancer

Inflammation plays a key role in the development of colorectal cancers. We have investigated the relationship between PTGS2 (COX2) polymorphisms and colorectal cancer risk in a hospital based case-control study. We recruited 292 patients with colorectal cancer and 274 controls from new patients admitted to Bellvitge Hospital, Barcelona, Spain, from 1996 to 1998. Subjects responded to a questionnaire on risk factors. Genotypes of the eight more frequent polymorphisms of PTGS2 were determined. Two polymorphisms are located in the promoter sequence, one in the untranslated region of exon 1, one in exon 3, one in intron 5, two in the untranslated region of exon 10, and one downstream of the last polyadenylation (poly-A) signal. Associations were analysed with logistic regression models assuming a dominant effect for rare variants to increase statistical power. An association was detected between colorectal cancer and a polymorphism in the untranslated region of exon 10 of PTGS2, with an odds ratio (OR) of 2.49, 95% confidence interval (CI) of 1.17-5.32, P=0.01. A nearby polymorphism downstream of the last poly-A signal also showed a nonsignificant increase in risk (OR 2.17, 95% CI 0.99-4.78, P=0.05). Analysis of haplotypes confirmed that individuals with these variants were at increased risk of colorectal cancer (OR compared to the most frequent haplotype: 2.17, 95% CI 0.97-4.84, P=0.06) Interactions between PTGS2 genotype and use of nonsteroidal anti-inflammatory drugs and risk of colorectal cancer were also explored.