VEGF在二甲双胍诱导HepG2细胞凋亡的作用

目的初步探讨二甲双胍(metformin,MET)诱导人肝癌HepG2细胞凋亡的分子机制.方法将不同浓度的MET(0-20 mmol/L)作用于HepG2细胞24 h或10 mmol/LMET作用于HepG2细胞不同时间(0-48 h),采用MTT法测定MET抑制细胞增殖效应.将HepG2细胞暴露于不同浓度的MET(0-20 mmol/L)作用24 h或10 mmol/L MET不同时间(0-48 h),用Annexin V-FITC/PI流式双染来测定其细胞凋亡率;用RT-PCR检测不同浓度MET作用于HepG2细胞或相同浓度作用于HepG2细胞不同时间后血管内皮生长因子(vascular endothelial growth factor,VEGF)表达的变化,以了解MET诱导HepG2细胞凋亡与VEGF的关系.结果MET对HepG2细胞生长有明显的抑制作用.不同浓度MET(0、5、10、15、20 mmol/L)处理HepG2细胞24 h后,其相对细胞活力分别为100%、80.56%±0.72%、71.06%±0.70%、64.73%±0.35%、54.73%±0.40%,呈现浓度依赖性;10 mmol/L MET作用于HepG2细胞0、12、24、36、48 h后,其相对相对细胞活力分别为100%、83.40%±0.70%、69.86%±0.45%、60.40%±0.88%、50.70%±0.45%,呈现时间依赖性.不同浓度MET(0、5、10、15、20 mmol/L)处理HepG2细胞24 h后,Annexin V-FITC/PI流式双染提示细胞凋亡明显增加,其凋亡率分别为2.78%±0.68%、9.33%±0.22%、17.13%±0.10%、21.61%±0.20%、25.26%±1.09%,呈现浓度依赖性;10 mmol/LMET作用于HepG2细胞12、24、36、48 h后,Annexin V-FITC/PI流式双染提示细胞凋亡明显增加,其凋亡率分别为2.05%±0.04%、8.10%±0.08%、16.53%±0.93%、20.95%±0.16%、25.65%±0.44%,呈现时间依赖性.随着MET浓度的升高或作用时间延长,VEGF的表达均减少,呈现剂量或时间依赖性.结论二甲双胍可以通过诱导HepG2细胞凋亡来抑制其增殖,其过程可能与抑制VEGF的表达有关.     

山萘酚对HepG2细胞凋亡的影响

目的探讨山萘酚对人类肝癌细胞系HepG2细胞凋亡的影响。方法以不同浓度的山萘酚孵育HepG2细胞24 h后选取最佳药物浓度100μmol/L,再以不同的时间孵育HepG2细胞。采用MTT法检测细胞存活率;采用乳酸脱氢酶(LDH)活力定量试剂盒检测细胞上清LDH活性;采用流式细胞术检测细胞凋亡率;采用蛋白印记法检测细胞凋亡相关蛋白的表达情况。结果山萘酚对HepG2细胞凋亡有诱导作用且呈剂量和时间依赖性。当山萘酚作用于HepG2细胞24 h后,随着山萘酚浓度的增加,细胞存活率逐渐降低,细胞凋亡率逐渐增高。与空白对照组相比,作用于HepG2细胞24 h后浓度为100μmol/L的山萘酚,细胞存活率显著降低[(60.58±3.74)%vs(100±2.28)%,P0.0001],细胞凋亡率明显升高[(16.43±0.07)%vs(0.68±0.09)%,P0.0001]。经蛋白印记检测,在山萘酚孵育HepG2细胞24 h的情况下,随着山萘酚浓度的增加,凋亡因子Cleaved-caspase3蛋白表达增加。当山萘酚浓度为100μmol/L时,随着山萘酚作用于HepG2时间的延长,细胞凋亡率也呈逐渐升高趋势。与空白对照组相比,浓度为100μmol/L的山萘酚作用于HepG2细胞24 h后,细胞存活率明显降低[(59.36±3.09)%vs(100±2.28)%,P0.0001],细胞凋亡率显著升高[(16.71±1.12)%vs(0.35±0.01)%,P0.0001],随着时间延长,Cleaved-caspase3表达增加。结论山萘酚对于人类肝癌细胞系HepG2细胞的凋亡具有诱导作用,呈剂量-时间依赖性。表明高浓度山萘酚可通过促进凋亡因子Cleavedcaspase3的表达诱导HepG2细胞凋亡,从而拥有潜在的抗肝癌活性作用。     

N-乙酰半胱氨酸对毒胡萝卜素诱导的HepG2细胞内质网氧化应激凋亡的影响

目的 了解N-乙酰半胱氨酸(NAC)对内质网氧化应激介导的肝细胞凋亡的阻抑作用.探讨其治疗肝细胞损伤的作用机制.方法 用毒胡萝卜素(TC)诱导HepG2细胞,建立内质网应激凋亡模型,用NAC进行干预.噻唑蓝(MTT)、流式细胞仪、DNA梯形电泳检测凋亡率及活性氧(ROS),Western印迹检测葡萄糖调节蛋白(GRP)78、Caspase-12酶原及ADP聚合酶(PARP)表达.多样本间均数采用方差分析.结果 用2μmol/L TG诱导HepG2细胞0、24、36和48 h,随诱导时间延长,细胞活力逐渐下降;GRP 78、Caspase-12酶原及PARP表达增高;凋亡率逐渐增加.分别是0.7%±0.5%、27.6%±6.3%、29.7%±3.03%和47.9%±3.5%(P<0.05);ROS产生逐渐增加,分别是14.0%±0.5%、36.1%±300%、38.2%±6.0%和48.3%±12.4%(P<0.05);诱导36、48 h后细胞出现典型DNA梯形条带.10 mmol/L、20 mmol/L NAC分别与2/μmol/L TG共同温育HepG2细胞后发现,NAC可明显提高细胞活力;抑制GRP 78、Caspase-12酶原及PARP表达,细胞凋亡率分别降至14.0%±1.3%和11.0%±0.3%;细胞内ROS的产生减至34.7%±0.8%与31.5%±2.9%.结论 TG作为一种内质网特异的钙离子ATP酶抑制剂,能触发HepG2细胞内质网氧化应激凋亡;而NAC作为巯基合成的前体.直接抑制氧自由基反应,阻断内质网氧化应激介导的细胞凋亡,减轻肝细胞损伤,达到临床治疗肝功能衰竭的作用.     

雌激素对人肝癌细胞增殖和凋亡的影响

目的探究雌激素对人肝癌细胞株增殖和凋亡的影响。方法采用普通聚合酶链反应(PCR)技术、Western印迹实验检测肝癌细胞株中雌激素受体(ER)α、ERβ的mRNA和蛋白质的表达情况;细胞增殖实验检测雌激素对肝癌细胞增殖的影响;流式细胞术检测雌激素对肝癌细胞凋亡率的影响;Tunel染色法检测雌激素对肝癌细胞晚期凋亡率的影响;雌激素处理肝癌细胞株后,基因芯片技术检测表达增加的凋亡基因。结果 ERα和ERβ在肝癌细胞株SMMC7721、HepG2、Bel-7404、huh7、MHCC-97L、MHCC-97H、PLC、LM3、SK-HEP-1及Bel-7402中均有表达;不同浓度的雌激素处理肝癌细胞不同时间后,可显著抑制肝癌细胞增殖,且抑制效果存在时间和剂量依赖性;与0.00μmol/L组相比,不同浓度的雌激素(1.25、2.50、5.00、10.00、20.00、40.00、80.00和160.00μmol/L)处理HepG2、SMMC-7721细胞24 h、48 h后,HepG2和SMMC-7721细胞的细胞凋亡率增加,存在剂量和时间的依赖性;Tunel结果显示,与0.00μmol/L组相比,10.00μmol/L雌激素处理HepG2、SMMC-7721细胞48 h后,细胞晚期凋亡率均显著增加;20.00μmol/L雌激素处理SMMC-7721细胞48 h后,凋亡基因BAK1、GADD45A、HRK、LTA、TNFRSF-10A均表达增加。结论雌激素对人肝癌细胞具有抑制生长、诱导凋亡的作用。     

缺氧诱导因子1α对肝癌细胞HepG2干细胞特性及表阿霉素敏感性的影响

目的探讨缺氧诱导因子(HIF)1α对肝癌细胞HepG2干细胞特性及表阿霉素敏感性的影响。方法以肝癌细胞为研究对象,肝癌细胞HepG2脂质体转染过表达HIF-1α的质粒作为实验组,转染pcDNA3.1空质粒作为对照组,单独HepG2细胞为HepG2组。实时荧光定量PCR检测HIF-1αmRNA表达,Western Blot检测HIF-1α蛋白表达;流式细胞术检测细胞表面CD133表达。不同浓度表阿霉素(0、6.25、12.5、25、50μmol/L)作用3组细胞24 h,MTT法检测细胞活性,流式细胞术检测表阿霉素(50μmol/L)处理后细胞凋亡情况。计量资料多组间比较采用单因素方差分析,进一步两两比较采用t检验。结果相较于HepG2组及对照组,实验组HIF-1αmRNA的表达水平明显升高,差异具有统计学意义(P值均<0.001);Western Blot结果显示实验组HIF-1α蛋白高表达。HepG2组、对照组和实验组细胞的CD133比例分别为0.040%±0.003%、0.030%±0.010%、20.110%±0.600%,实验组的CD133阳性率显著高于HepG2组和对照组(P值均<0.001)。表阿霉素浓度为25、50μmol/L时,HepG2组和对照组的细胞活性明显受到抑制,显著低于实验组(P值均<0.05)。50μmol/L表阿霉素作用48 h后,实验组的细胞凋亡率(67.9%±2.5%)较HepG2组(93.6%±1.5%)和对照组(93.0%±1.2%)明显降低(P值均<0.001)。结论过表达HIF-1α的质粒成功转染至HepG2细胞,HIF-1α可提高肝癌细胞干细胞比例使其对表阿霉素耐药。     

地西他滨联合阿霉素对TP53突变弥漫大B淋巴瘤细胞株的影响及临床意义研究

目的:观察地西他滨对TP53突变弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma, DLBCL)细胞株DB增殖、凋亡及周期的影响,并评估地西他滨联合治疗TP53突变DLBCL患者的疗效及安全性。方法:体外培养细胞,不同浓度(5～80μmol/L)地西他滨和阿霉素作用于DB细胞后采用CCK-8法计算增殖抑制率;地西他滨(20μmol/L)和阿霉素(12μmol/L)作用于DB细胞24/48 h,采用Annexin V-FITC/PI及流式细胞术检测凋亡率及细胞周期;比较不同组间细胞增殖、凋亡及周期的差异。另收集5例地西他滨联合治疗TP53突变DLBCL患者的临床资料进行回顾性总结。结果:对DB细胞的增殖抑制作用随着地西他滨浓度的增加(5、10、20、40、80μmol/L)而增强,联合阿霉素(12μmol/L)后抑制率较单药明显增大[(78.51±1.19)%vs (40.80±1.62)%,(87.48±0.29)%vs (46.83±1.47)%,(92.59±0.15)%vs (47.07±1.50)%,(94.57±0.58)%vs (52.68±0...     

没药甾酮对人肝癌细胞HepG2增殖和凋亡的影响

目的研究没药甾酮对人肝癌细胞HepG2增殖和凋亡的影响。方法以正常人肝细胞L-02作为对照,采用3-（4,5-二甲基噻唑-2）-2,5-二苯基四氮唑溴盐法观察不同浓度没药甾酮（5～100μmol/L）对人肝癌细胞HepG2和L-02细胞增殖的影响并观察细胞形态的变化;应用流式细胞术检测细胞周期变化和凋亡发生。结果不同浓度没药甾酮均可显著抑制人肝癌细胞HepG2生长,并呈时间、剂量依赖性,最大抑制率可达81.9%±1.92%（100μmol/L）;没药甾酮可使G0/G1期细胞比例增多,G2/M期细胞比例下降,可将细胞阻滞于G0/G1期;没药甾酮诱导人肝癌细胞HepG2发生凋亡,50μmol/L和75μmol/L没药甾酮早期细胞凋亡率分别为24.91%±2.41%、53.03%±2.28%,与对照组相比,差异均具有统计学意义（P〈0.05）。结论没药甾酮可抑制人肝癌细胞HepG2增殖并诱导凋亡,其作用可能与干扰细胞周期有关。     

维生素K_2对大鼠HepG2细胞侵袭和凋亡的影响及机制

目的探讨维生素K_2对大鼠HepG2细胞侵袭和凋亡的影响及机制。方法选取对数生长期的HepG2细胞,培养48h后加入不同浓度(1μmol/L、10μmol/L、20μmol/L)的维生素K_2,同时设置对照组(仅加培养液),培养48 h后检测HepG2细胞的增殖、侵袭和凋亡以及肝癌衍生生长因子(hepatoma derived growth factor,HDGF)的表达。结果维生素K_2呈现剂量依赖性抑制HepG2细胞增殖、增加细胞凋亡指数并抑制HepG2细胞的穿透能力,与对照组相比差异均有统计学意义(P均0.05)。维生素K_2可呈现剂量依赖性抑制HDGF mRNA与蛋白表达水平,实验组表达水平显著低于对照组(F=20.332,P 0.001)。结论维生素K_2可抑制大鼠HepG2细胞的增殖、侵袭并促进凋亡,其作用机制可能与抑制HDGF基因与蛋白表达有关。     

肝癌细胞对5-氮杂-2'-脱氧胞苷的敏感性与细胞总DNA甲基化水平无关

目的 比较不同肝癌细胞株对5-氮杂-2'-脱氧胞苷(5-aza-dC)的敏感性,探讨肝癌细胞对5-aza-dC的敏感性是否与细胞总DNA甲基化水平有关.方法 用不同剂量(0.5、5.0、10.0μmol/L)的5-aza-dC处理肝癌细胞株(HepG2、QGY7701和HepG2.2.15细胞)及正常肝细胞株L02,比较不同浓度处理前后的细胞增殖抑制率,比较10 μmol/L 5-aza-dC处理前后的Caspase-3活性及细胞DNA片段化水平(5-溴脱氧尿嘧啶核苷掺入率),比较不同细胞总DNA甲基化水平.组间检测结果比较采用t检验.结果 5-aza-dC对HepG2、QGY7701、HepG2.2.15、L02细胞的半数抑制浓度分别为0.5、0.5、4.5、11.4μmol/L,与HepG2细胞和QGY7701细胞相比,HepG2.2.15绌胞和L02细胞对5-aza-dC不敏感.HepG2和QGY7701细胞中Caspase-3的活性升高较L02和HepG2.2.15细胞明显(P值均＜0.05),QGY7701细胞中5-溴脱氧尿嘧啶核苷掺入率升高较L02细胞明显(P＜0.05).L02、HepG2、QGY7701和HepG 2.2.15细胞的DNA总甲基化水平分别为11.7%±0.9%、10.9%±1.3%、11.7%±1.7%和12.2%±1.0%,差异无统计学意义(P值均＞0.05).结论 细胞对5-aza-dC的敏感性与细胞总DNA甲基化水平无关.     

辛二酰苯胺异羟肟酸对人肝癌SMMC-7721细胞增殖和凋亡的影响

目的：探讨辛二酰苯胺异羟肟酸（SAHA）对人肝癌细胞株SMMC-7721细胞增殖和凋亡的影响。方法体外培养SMMC-7721细胞,给予不同浓度（2.5、5.0和7.5μmol/L）SAHA处理12~72h,采用噻唑蓝（MTT）比色法检测细胞增殖;加入SAHA（5.0和7.5μmol/L）处理SMMC-7721细胞24h或48h,使用流式细胞仪检测细胞凋亡和细胞周期的变化;采用RT-PCR法检测p53、bcl-2及bax基因mRNA水平;采用分光光度法检测Caspase-3蛋白表达。结果经5.0μmol/L SAHA处理细胞24h和48h时,细胞增殖率较对照下降了25.8%和28.8%,经7.5μmol/L SAHA处理细胞24h和48h时,下降了30.6%和48.6%;经5.0μmol/L或7.5μmol/L SAHA处理细胞24 h后,S期细胞从对照水平（24.33±0.17）%分别显著上升至（32.08±0.160）%和（33.96±0.20）%,（P=0.00）,早期凋亡率均由（0.19±0.04）%显著上升至（1.67±0.59）%和（8.92±0.94）%,（P=0.03）,而在48h后,S期细胞由（24.33±1.18）%分别显著上升至（32.25±0.53）%和（34.61±0.08）%,早期凋亡率由（0.19±0.04）%分别显著上升至（14.49±2.26）%和（26.23±0.55）%,（P=0.00）;SAHA能够上调p53、bax基因mRNA水平,下调bcl-2基因mRNA水平;经5.0μmol/L和7.5μmol/L SAHA处理细胞24h后,Caspase-3蛋白活性由对照水平（0.41±0.07）分别上升至（0.81±0.02）,（P=0.01）和（1.09±0.21）,（P=0.00）,而在处理48 h后,Caspase-3蛋白活性由对照水平分别上升至（1.43±0.23）和（2.01±0.01）,（P均=0.00）。结论 SAHA通过影响p53、bcl-2及bax凋亡相关基因水平及Caspase-3蛋白的活性,对人肝癌细胞株SMMC-7721细胞具有抑制增殖和促进凋亡的作用。     

邻苯二甲酸二(2-乙基已)酯对胰岛MIN6β细胞毒性作用的研究

目的 观察邻苯二甲酸二(2-乙基已)酯(DEHP)对胰岛MIN6 β细胞生长活力、细胞周期及细胞凋亡的影响.方法 选用小鼠胰岛MIN6 β细胞作为研究对象,并将其分为DEHP组和对照组,DEHP组分别用0.25、0.5、1、2 mmol/L DEHP作用16、48、72 h.对照组用0.1％二甲基亚砜(DMSO)作用16、48、72 h.通过MTT实验检测细胞生长活力,流式细胞技术测定细胞凋亡率及细胞周期.结果 与对照组相比,在16、48及72 h随着DEHP浓度的增加,MIN6 β细胞生长活力受到抑制,细胞存活率明显下降(F=112.25、91.06、589.25,P均＜0.01);0.25、0.5、1 mmol/L DEHP组MIN6 β细胞凋亡率明显升高[(5.00±0.22)％、(8.33±0.09)％、(19.62±0.44)％,F=3 006.09,P＜0.01];0.5、1 mmol/L DEHP组受到MIN6 β细胞周期进程受到干扰,G0/G1期细胞比例[(68.50±0.89)％、(73.63±0.96)％,F=242.46,P＜0.01]明显升高,S期细胞[(17.57±1.15)％、(14.40％±0.91)％,F=49.28,P＜0.01]与G2/M期[(13.93±0.42)％、(11.97±1.85)％,F=72.70,P＜0.01]比例明显降低.结论 DEHP可抑制胰岛MIN6 β细胞增殖、诱导细胞凋亡、导致细胞周期停滞在细胞间期.     

Effect of blocking IGF-Ⅰ receptor on growth of human hepatocellular carcinoma cells

AIM: To study the expression level and localization of insulin-like growth factor -Ⅰ receptor (IGF-IR) in HepG2 cells and Chang liver cells, and to observe the effect of anti-IGF-IR monoclonal antibody (αIR3) on the growth of HepG2 cells.METHODS: The expression of IGF-IR in HepG2 cells and Chang liver cells was detected by immunohistochemistry.The influences of αIR3 on proliferation and apoptosis were examined by the 3- (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and electron microscopy, respectively. Flow cytometry (FCM) was applied for the analysis of cell cycle and apoptosis was observed under electron microscope.RESULTS: IGF-IR was located in the membranes of both HepG2 and Chang liver cell lines, and the expression level of IGF-IR was higher in HepG2 cells than in Chang liver cells. Treated with 0.1 μg/mL αIR3 for 48 h in vitro, the cell growth index (GI) of HepG2 cells was significantly higher than that of control (103.41% vs 100%, P ＜ 0.01).However, the αIR3 for 24 h at final concentration of 4.0 μg/mL made the GI of HepG2 cells lower than that of control (93.37% vs 100%, P ＜ 0.01). Compared with control, treated with αIR3 for 48 h at final concentrations ranging from 1.0 μg/mL to 4.0 μg/mL markedly reduced the GIs of HepG2 cells (97.63%, 97.16%, 95.13%,92.53% vs 100%, P ＜ 0.05 or P ＜ 0.01), treated with αIR3 for 72 h at final concentrations ranging from 0.2 μg/mL to 4.0 μg/mL decreased the GIs of HepG2 cells obviously (95%, 91.63%, 90.77%, 89.84%, 88.51% vs 100%, P ＜ 0.01), and treated with αIR3 for 96 h at final concentrations ranging from 0.5 μg/mL to 4.0 μg/mL made GIs of HepG2 cells lower significantly (88.86%,83.97%, 79.81%, 77.24%, 70.51% vs 100%, P ＜ 0.05 or ,P ＜ 0.01). Moreover, treated with αIR3 from 24 h to 96 h at final concentrations ranging from 0.2 μg/mL to 4.0 μg/mL reduced the GI of HepG2 cells from 97.63% to 70.51% in a dose- and time-dependent manner. Also,αIR3 treatment for 72 h at final concentration from 0.5 μg/mL to 2.0 μg/mL increased the proportion of G0/G1 phase cells(61.73%, 67.1%, 83.7%,76.87% vs 44.47%,P ＜ 0.01) and significantly decreased that of S phase cells(28.63%, 25.13%, 15.63%, 23.13% vs 53.17%, P ＜ 0.01), in contrast to the proportion of G2/M phase cells.The apoptotic rates of HepG2 cells were increased more than that of control (7.83%, 16.13%, 21.1%, 37.73% vs 4.13%, P ＜ 0.01).CONCLUSION: The malignant cell phenotype of human hepatocarcinoma cell is related to overexpression of IGFIR. The blockage of IGF-IR with αIR3 may contribute to the inhibition of proliferation and induction of apoptosis in HepG2 cells.     

AMP-活化蛋白激酶对氧葡萄糖剥夺复氧PC12细胞HMGB1释放及其介导的BY2细胞炎性反应的影响

目的 探讨调节AMP-活化蛋白激酶(AMP-activated protein kinase,AMPK)对PCl2细胞氧葡萄糖剥夺复氧(oxygen glucose deprivation and reoxygenation,OGD/R)后高迁移率族蛋白l(high mobility group box l,HMGB1)释放及其介导的BV2细胞炎性反应的影响.方法 分别培养PCl2和BV2细胞,应用PCl2细胞建立氧葡萄糖剥夺12 h复氧24 h模型,分别给予5-氨基-4-甲酰胺咪唑核糖核苷酸(5-aminoimidazole-4-c arboxamide,AICAR)5、50和100 μmol/L以及Compound C 0.1、l和10 μmol/L激活或抑制AMPK磷酸化后,应用四甲基偶氮唑蓝(methyl thiazolyl tetrazolium,MTT)法检测PC12细胞活性,酶联免疫吸附法检测PC12细胞培养基中HMGB1释放水平.将各组OGD/R后PC12培养基分别作用于BV2细胞正常培养24 h.分别采用免疫印迹法和酶联免疫吸附法检测BV2细胞中NF-κB抑制蛋白(inh~itor of NF-κB,IκB)磷酸化水平和TNF-α释放水平.结果 OGD/R后,PC12细胞活性显著降低[(68.84 ±6.60)％对(100.04±8.82)％;P＜0.01],AMPK磷酸化水平显著增高(1.95±0.39对1.00±0.20;P＜0.05),细胞外HMGB1释放显著增多[(287.66±26.42) pg/μl对(53.05±9.11) pg/μl;P ＜0.01].与OGD/R组比较,AICAR 100 μmol/L能显著增高OGD/R后PC12细胞存活率[(78.60±3.75)％对(68.84±6.60)％;P＜0.05]、促进AMPK磷酸化(3.32±0.66对1.95 ±0.39;P＜ 0.01)和减少细胞外HMGB1的释放[(164.06±12.77) pg/μl对(287.66±26.42) pg/μl;P＜0.01].相比之下,Compound C 10 μmol/L则会显著降低PC12细胞存活率[(40.44±3.79)％对(68.84±6.60)％;P＜0.01]、抑制AMPK磷酸化(1.07±0.21对1.95±0.39;P＜0.05)和增加HMGB1的释放[(337.97±18.90) pg/μl对(287.66±26.42) pg/μl;P＜0.01].AICAR 100 μmol/L组条件培养基能显著抑制BV2细胞的IκB磷酸化(1.68±0.51对3.09±0.10;P＜0.05)和减少TNF-α释放[(669.53±38.58) pg/μl对(841.76±45.82) pg/μ1;P＜0.05];Compound C 10 μmol/L组条件培养基则能显著促进BV2细胞IκB磷酸化(4.98±1.24对3.09 ±0.10;P ＜0.01)和增加TNF-α释放[(1 035.32±128.06) pg/μl对(841.76±45.82) pg/μl;P＜0.05].结论 促进AMPK磷酸化激活能减少PC12细胞OGD/R后HMGB1的释放、抑制其介导的BV2细胞NF-κB炎症通路激活并且减少TNF-α释放,从而减轻神经炎性损伤;相反,抑制AMPK磷酸化则会促进PC12细胞OGD/R后HMGB1释放和加重其介导的BV2细胞炎性反应.     

Nucleoside transporters,bcl-2 and apoptosis in CLL cells exposed to nucleoside analogues in vitro

The purine nucleoside analogues fludarabine (Fl) and chlorodeoxyadenosine (2-CdA) are considered to be cell cycle specific agents which require DNA synthesis for cytotoxicity. However, their efficacy in the treatment of CLL, an indolent lymphoid malignancy suggests additional mechanisms of action. Like cytosine arabinoside (AraC), Fl and 2-CdA gain access to the cell via a specific nucleoside transporter (NST) protein. To investigate the mode of action of these drugs in CLL, we used a fluorescent ligand for the NST (5‘-(SAENTA- x 8)-fluorescein) and 3-colour flow cytometry to determine NST expression on CD5⁺/CD19⁺ B-cells from the peripheral blood (PB) of patients with CLL. NST levels on these cells was found to be not significantly different from normal control lymphocytes (mean = 485±425) vs. (mean = 553±178). Exposure to varying concentrations (0, 3 μM and 30 μM) of Fl and 2-CdA, however, resulted in an upregulation of NST (mean = 1552±775 with 30 μM FL; mean = 3392±2197 with 30 μM 2-CdA) after 48 h. “Large” lymphoid cells (not present in normal PB) were found to express significantly more NST (mean = 2540±2861) and have a higher proliferative capacity than “small” cells (mean = 357±517 NST/cell). Incubation of CLL cells with Fl (n = 6) and 2-CdA (n = 8) in vitro over 48 h also resulted in an increase in the proportion of cells in S-phase (0 μM = 0.2±0.1; 30 μM FL = 2.4±2.0; 30 μM 2-CdA = 3.3±1.3) and a significant increase in morphologically identifiable apoptosis. Apoptosis was confirmed by flow cytometric DNA analysis (0 μM = 13±8%; 30 μM FL = 40±20%; 30 μM 2-CdA = 48±11%). In situ hybridization using a biotinylated cDNA bcl-2 probe demonstrated that bcl-2 mRNA expression was markedly decreased in treated cells after 24 h. These studies have demonstrated that: (1) NST expression on CLL lymphocytes is low; (2) in vitro exposure to the analogues increases both the level of NST expression and the % cells in S-phase; (3) exposure to the analogues downregulates bcl-2 expression and increases apoptosis.     

乙型肝炎病毒X基因下调miR-192对人肝癌细胞株HepG2凋亡的影响

目的 探讨乙型肝炎病毒X基因(HBx)通过调节人肝癌细胞株HepG2中miR-192的表达而抑制其凋亡的机制.方法 设立3个细胞组:稳定转染HBx基因的HepG2细胞(HepG2/HBx),稳定转染空载体pcDNA3.1的HepG2细胞(HepG2/pcDNA3.1)以及未作转染的HepG2细胞.用流式细胞术分析3个细胞组的凋亡率差异,用Taqman探针荧光定量PCR检测3组细胞中miR-192的表达水平.转染miR-192后,用流式细胞术检测HepG2细胞凋亡率的变化,同时用SYBR Green荧光定量PCR和Western blot检测细胞中p53、PUMA表达的变化.计量资料均数的比较用单因素方差分析.结果 HepG2/HBx细胞的凋亡率为2.37％±0.35％,较HepG2/pcDNA3.1、HepG2细胞(11.46％±0.69％、12.50％±0.66％)明显降低(F=171.722,P＜0.01).miR-192表达在HepG2/HBx细胞中为49.1％±5.9％,较HepG2/pcDNA3.1、HepG2细胞(98.0％±8.9％,100％)也明显下调(F=14.319,P＜ 0.05).转染miR-192后HepG2细胞的凋亡率(15.74％±1.17％)较转染相应阴性对照的HepG2细胞的凋亡率(10.74％±1.15％)显著升高(F=18.415,P＜0.05),同时,p53、PUMA基因在mRNA (953:1.68±0.12比0.90±0.09,F=43.115,P＜0.05 ; PUMA:1.66±0.10比0.98±0.06,F=22.541,P＜0.05)和蛋白质水平(p53:3.07比1,PUMA:2.13比1)的表达均显著上升.结论 miR-192促进HepG2细胞凋亡,HBx通过下调miR-192抑制HepG2细胞凋亡.     

吡格列酮对成骨细胞Bax、Bcl-2蛋白表达的影响

目的 研究吡格列酮对成骨细胞增殖及凋亡的影响,并进一步了解其凋亡发生机制.方法 以MC3T3-E1成骨细胞株为实验对象,分别用0、5、10、20、30、40 μmol/L吡格列酮干预,观察细胞活性、细胞周期及凋亡率的变化,同时检测细胞Bcl-2,Bax蛋白表达.结果 随着浓度增加,成骨细胞的活性逐渐降低;与对照组相比,G0/G1,G2/M期细胞增多,S期细胞明显减少;凋亡率在5、10 μmol/L时低于对照组,30、40 μmol/L较对照组显著增高;Bax表达在10 μmol/L时明显减弱,20 μmol/L时回复到正常,30、40μmol/L较对照组显著增强;Bcl-2表达在浓度≤20 μmol/L时显著增强;对于Bax/Bcl-2相对表达强度与细胞凋亡率做相关性分析,两者呈显著性正相关(n=15,r=0.796,P＜0.01).结论 吡格列酮在低浓度抑制成骨细胞凋亡,对细胞起保护作用,较高浓度则促进细胞凋亡,Bax/Bcl-2参与其凋亡机制,并可能起关键调控作用.吡格列酮抑制成骨细胞DNA合成,抑制细胞增殖,导致细胞活性下降.

Abstract：

Objective To investigate the effects of pioglitazone on osteoblast proliferation and apoptosis.Methods MC3T3-E1 mouse osteoblastic cells were treated with 0, 5, 10, 20, 30, and 40 μmol/L pioglitazone for 24 h. Cell viability was measured by MTT, cell cycle and apoptosis were inspected with flow cytometry, the expressions of Bcl-2 and Bax proteins were examined via immuno-chemical staining. Results Survival of osteoblasts decreased in a dose-dependent manner. Compared with the control group, the cells in the G0/G1 and G2/M stages increased, while the cells in S stage decreased significantly. The percentage of apoptosis at 5 and 10 μmol/L were lower than that of the control group(P ＜ 0.05), While it was increased significantly at 30 and 40 μmol/L(P ＜0.01). Bax expression was attenuated at 10 μmol/L(P＜0. 01), returned to normal by 20 μmol/L, and was increased by 30 and 40 μmol/L(P ＜ 0. 01). Bcl-2 expression was enhanced at the dose ≤ 20 μmol/L(P ＜0.01). Positive correlation was found between the death rate and the expression intensity of Bax/Bcl-2(n = 15, r=0.796, P＜0.01). Conclusions Pioglitazone inhibits apoptosis of osteoblasts at low concentrations and protects the cells, but promotes their apoptosis at higher concentration, Bax/Bcl-2 may play an important role in mediating the piglitazone-induced apoptosis of osteoblasts. It inhibits DNA synthesis and cell proliferation.     

Induction of apoptosis in human liver carcinoma HepG2 cell line by 5-allyl-7-gen-difluoromethylenechrysin

AIM： To investigate the effect of 5-allyl-7-gen-difluoromethylenechrysin （ADFMChR） on apoptosis of human liver carcinoma HepG2 cell line and the molecular mechanisms involved.METHODS： HepG2 cells and L-02 cells were cultured in vitro and the inhibitory effect of ADFMChR on their proliferation was measured by MTT assay. The apoptosis of HepG2 cells was determined by flow cytometry （FCM） using propidium iodide （PI） fluorescence staining. DNA ladder bands were observed by DNA agarose gel electrophoresis. The influence of ADFMChR on the proxisome proliferator-activated receptor γ （PPARγ）, NF-κB, Bcl-2 and Bax protein expression of HepG2 cells were analyzed by Western blotting.RESULTS： MTT assay showed that ADFMChR significantly inhibited proliferation of HepG2 cells in a dose- dependent manner, with little effect on growth of L-02 cells, and when ICs0 was measured as 8.45 μmol/L and 191.55 μmol/L respectively, the potency of ADFMChR to HepG2 cells, was found to be similar to 5-fluorouracil （5-FU, ICso was 9.27 μmol/L）. The selective index of ADFMChR cytotoxicity to HepG2 cells was 22.67 （191.55/8.45）, higher than 5-FU （SI was 7.05 （65.37/9.27）. FCM with PI staining demonstrated that the apoptosis rates of HepG2 cells treated with 3.0, 10.0 and 30.0 μmol/L ADFMChR for 48 h were 5.79%, 9.29% and 37.8%, respectively, and were significantly higher when treated with 30.0 μmol/L ADFMChR than when treated with 30.0 μmol/L ChR （16.0%） （P 〈 0.05） and were similar to those obtained with 30.0 μmol/L 5-FU（41.0%）. DNA agarose gel electrophoresis showed that treatment of HepG2 cells with 10.0 μmol/L ADFMChR for 48 h and 72 h resulted in typical DNA ladders which could be reversed by 10.00 pmol/1 GW9662, a blocker of PPARy. Western blotting analysis revealed that aEer 24 h of treatment with 3.0, 10.0, 30.0 μmol/L ADFMChR, PPARy and Bax protein expression in HepG2 cells increased but Bcl-2 and NF-κB expression decreased; however, pre-incubation with 10.0 μmol/L GW9662 could efficiently antagonize and weaken the regulatory effect of 3.0, 30.0 μmol/L ADFMChR on PPARy and NF-KB protein expression in HepG2 cells.CONCLUSION： ADFMChR induces apoptosis of HepG2 cell lines by activating PPARγ, inhibiting protein expression of Bcl-2 and NF-κB, and increasing Bax expression.     

Overexpression of cyclooxygenase-2 in human HepG2, Bel-7402 and SMMC-7721 hepatoma cell lines and mechanism of cyclooxygenase-2 selective inhibitor celecoxib-induced cell growth inhibition and apoptosis

AIM: To investigate the cyclooxygenase-2 (COX-2)expression level in human HepG2, Bel-7402 and SMMC-7721hepatoma cell lines and the molecular mechanism of COX-2 selective inhibitor celecoxib-induced cell growth inhibition and cell apoptosis.METHODS: Hepatoma cells were cultured and treated with celecoxib. Cell in situ hybridization (ISH) and immunocytochemistry were used to detect COX-2 mRNA and protein expression. Proliferating cell nuclear antigen and phosphorylated Akt were also detected by immunocytochemistry assay. Cell growth rates were assessed by 3-(4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium (MTT) bromide colorimetric assay. Celecoxibinduced cell apoptosis was measured by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and flow cytometry (FCM). The phosphorylated Akt and activated fragments of caspase-9, caspase-3 were examined by Western blotting analysis.RESULTS: Increased COX-2 mRNA and protein expression were detected in all three hepatoma cell lines. Celecoxib could significantly inhibit cell growth and the inhibitory effect was in a dose- and time-dependent manner evidenced by MTr assays and morphological changes.The apoptotic index measured by TUNEL increased correspondingly with the increased concentration of celecoxib and the reaction time. With 50 μmol/L celecoxib treatment for 24 h, the apoptotic index of HepG2, BEL-7402and SMMC-7721 cells was 25.01±3.08%, 26.40±3.05%,and 30.60±2.89%, respectively. Western blotting analysis showed remarkable activation of caspase-9, caspase-3and dephosphorylation of Akt (Thr308). Immunocytochemistry also showed the reduction of PCNA expression and phosphorylation Akt (Thr308) after treatment with celecoxib.CONCLUSION: COX-2 mRNA and protein overexpression in HepG2, Bel-7402 and SMMC-7721 cell lines correlate with the increased cell growth rate. Celecoxib can inhibit proliferation and induce apoptosis of hepatoma cell strains in a dose- and time-dependent manner.     

黄芩苷对体外氧化应激模型中肝型脂肪酸结合蛋白表达的影响及其意义

目的 研究黄芩苷对体外氧化应激模型中肝型脂肪酸结合蛋白(L-FABP)表达的影响及其意义. 方法 用终浓度为400 μ mol/L的过氧化氢(H2O2) 37℃避光孵育细胞20min,建立体外诱导氧化应激模型.应用甲基噻唑基四唑法(MTT)检测不同浓度黄芩苷作用细胞的存活率,确定24h、48 h黄芩苷的半数中毒浓度(TC50).流式细胞技术检测不同浓度黄芩苷(25、50、100μmol/L)作用后活性氧(ROS)的表达、细胞内超氧化物歧化酶(SOD)和谷胱甘肽(GSH)活性变化,实时PCR和Western blot检测肝细胞内L-FABP基因和蛋白表达.数据分析采用单因素方差分析.结果 根据MTT法得出25、50、100 μ mol/L的黄芩苷作用于细胞24h的存活率为83.60％±3.47％,72.36％±2.18％,70.16％±2.04％,F值为386.24,P＞0.05;作用于细胞48h的存活率为84.93％±3.11％,76.16％±2.45％,72.72％±2.31％,F值为475.92,P＞0.05.直线回归法得出黄芩苷持续作用24h和48h的TC50分别为153.2、170.6μmol/L.在此范围内,用25、50、100μmol/L浓度的黄芩苷分别作用Chang肝细胞24、48 h后,ROS含量24 h分别为37.0±3.30,22.90±3.84,29.60±2.52,F值为70.06,P＜0.05 ; 48h分别为35.77±2.35,21.80±3.10,23.87±1.98,F值为110.92,P＜0.05,而400μ mol/L H2O2组ROS含量24h和48h分别为45.50±3.47,48.80±2.70,以50μmol/L的黄芩苷作用48h效果最为显著.用50μmol/L黄芩苷处理48h后细胞内SOD活性为(51.53±1.91)μ g/mg,GSH为(49.85±1.45) U/mg;与对照组SOD为(26.36±1.23)μ g/mg,GSH为(25.11±1.74) U/mg,F值分别为93.81和92.51,P值均＜0.05).尽管50μmol/L黄芩苷处理48 h后细胞内L-FABP在mRNA水平并无明显变化,但50μmol/L黄芩苷处理48 h后细胞内L-FABP蛋白表达与对照组相比增加约80％.结论 黄芩苷能通过增强L-FABP蛋白表达,增加细胞内SOD和GSH的活性发挥抗氧化作用.