厄洛替尼对人胰腺癌细胞凋亡及survivin蛋白表达的影响

目的 研究厄洛替尼对人胰腺癌细胞PANC-1凋亡及survivin蛋白表达的影响.方法 培养人胰腺癌细胞,培养液中加入不同浓度厄洛替尼,MTT比色法检测PANC-1细胞增殖变化,流式细胞学检测PANC-1细胞的凋亡率;Western印迹检测survivin蛋白的表达情况.结果 厄洛替尼能明显抑制胰腺癌PANC-1细胞的生长,随用药时间的延长和用药浓度的提高,抑制率明显增强(P＜0.05);12.5 μmol/L厄洛替尼作用24、48、72 h的PANC-1细胞凋亡率(％)分别为9.51±1.38,14.50±1.65,16.6±1.89.结论 厄洛替尼通过下调survivin蛋白的表达诱导人胰腺癌细胞PANC-1凋亡,从细胞水平为其抗肿瘤浸润提供了新的治疗思路和实验依据.     

LncRNA-PVT1对人胰腺癌细胞株HPAF-Ⅱ增殖和凋亡的影响

背景:近年来,长非编码RNA(lncRNAs)在肿瘤发生、发展中的作用日益受到重视。研究发现lncRNA-PVT1在多种人类恶性肿瘤中表达上调并发挥促癌作用。目的:探讨PVT1在人胰腺癌细胞中的表达及其对HPAF-Ⅱ细胞增殖和凋亡的影响。方法:以脂质体转染技术将siRNA-PVT1转染入HPAF-Ⅱ细胞;以real-time PCR检测PVT1mRNA表达,MTS实验和平板克隆形成实验检测细胞增殖能力,流式细胞分析检测细胞周期和细胞凋亡,蛋白质印迹法检测凋亡相关蛋白和原癌基因蛋白c-Myc表达。结果:以人永生化正常胰腺导管上皮细胞株H6c7作为对照,各人胰腺癌细胞株中以HPAF-Ⅱ细胞PVT1 mRNA表达升高最为明显。与转染阴性对照siRNA和未予转染siRNA的细胞相比,转染siRNA-PVT1的HPAF-Ⅱ细胞PVT1 mRNA表达显著降低,细胞增殖能力减弱,发生细胞周期G1期阻滞并出现凋亡峰,细胞中凋亡相关蛋白cleaved-caspase-3、cleaved-PARP表达上调,Bcl-2/Bax比值降低,c-Myc蛋白表达下调。结论:LncRNA-PVT1在人胰腺癌细胞株HPAF-Ⅱ中呈高表达,其可能通过调控c-Myc表达影响HPAF-Ⅱ细胞的增殖和凋亡。     

吉西他滨对胰腺癌PANC-1细胞中组蛋白去乙酰化酶及TMS1/ASC基因表达的影响

目的检测吉西他滨（GEM）对胰腺癌细胞株PANC-1中甲基化诱导静止基因（TMS1/ASC）及组蛋白去乙酰化酶（HDAC）表达的影响,并探讨组蛋白去乙酰化与TMS1/ASC之间的关系。方法 4.27μg/ml GEM作用于PANC-1细胞,运用透射电镜观察GEM对胰腺癌细胞PANC-1形态的影响。蛋白印迹法（Western blotting）检测HDAC的表达,用重亚硫酸盐测序PCR（BSP）和结合重亚硫酸盐的限制性内切酶法（COBRA）检测TMS1/ASC启动子区域甲基化状态。结果 TMS1/ASC在胰腺癌细胞株PANC-1中发生甲基化,经5-杂氮-2＇-脱氧胞苷（5-aza-dC）处理后,PANC-l细胞TMS1/ASC重新表达,GEM诱导胰腺癌细胞株PANC-1中TMS1/ASC未发生甲基化。HDAC在GEM诱导胰腺癌细胞株PANC-1中表达水平低于正常对照组。结论 GEM能抑制胰腺癌PANC-1细胞增殖并促进凋亡,随着作用时间的延长,其药物敏感性减低。GEM可能通过促进组蛋白发生乙酰化和抑制TMS1/ASC启动子甲基化来治疗胰腺癌。     

RNAi沉默survivin基因对胰腺癌细胞增殖、凋亡和周期的影响

目的 应用RNAi技术沉默胰腺癌细胞株中survivin基因对肿瘤细胞凋亡、细胞周期和增殖的变化.方法 靶向survivin的RNAi载体转染胰腺癌细胞,Western印迹检测基因沉默效果,MTT法和流式细胞术检测细胞增殖、凋亡及细胞周期.结果 survivin基因沉默效率可达85%;MTT检测显示,干扰组survivin沉默细胞增殖抑制与非特异性质粒对照组相比显著增高(P<0.01).流式细胞术显示,干扰组细胞凋亡百分率显著高于非特异性质粒对照组(P<0.01);G_2/M期显著高于非特异性质粒对照组(P<0.01或P<0.05),而S期则显著降低(P<0.05).结论 survivin基因沉默可引起胰腺癌细胞周期阻滞,促进细胞凋亡,抑制细胞增殖.     

RNA介导Survivin基因沉默对胰腺癌细胞Panc-1细胞株凋亡及增殖的影响

目的观察靶向封闭survivin基因对胰腺癌细胞株Panc-1增殖和凋亡的影响，探讨survivin基因在胰腺癌的发生、发展中作用：方法设计2对survivin-shRNA，体外转录制备shRNA。利用脂质体转染技术将survivin-shRNA转染胰腺癌细胞株（Panc-1），RT-PCR检测survivin-mRNA水平；MTT法检测细胞生长情况并绘制细胞生长曲线；细胞形态学观察及流式细胞仪分析细胞凋亡。结果转染2对survivin-shRNA可分别使Panc-1细胞survivin-mRNA水平下降54．86％，52．19％；MTT法检测结果显示：转染两对survivin-shRNA24、48、72小时对细胞增殖无明显影响（P〉0．05）；细胞形态学观察及流式细胞仪分析结果显示：转染两对survivin-shRNA 24、48、72小时对细胞凋亡无明显影响（P〉0．05）。结论应用RNAi技术，将survivin-shRNA转染胰腺癌细胞（Panc-1），能成功介导survivin基因沉默，达到部分靶向封闭survivin的目的：部分靶向封闭survivin对胰腺癌细胞株Panc-1凋亡及增殖无明显影响。提示：survivin在胰腺癌细胞增殖与凋亡调控中所起的作用可能并非关键性的。因而以survivin为靶基因的基因治疗对胰腺癌可能无效。     

survivin反义寡核苷酸对SMMC-7721细胞增殖和凋亡的影响

目的 观察survivin反义寡核苷酸(ASODN)对人肝癌细胞株SMMC-7721增殖和凋亡的影响.方法 人工合成survivin基因ASODN和正义ODN(SODN),并行硫代磷酸化修饰,通过脂质体途径转染SMMC-7721;分别用RT-PCR和Western blot检测survivin mRNA和蛋白表达;用MTT法检测ASODN对SMMC-7721增殖的影响;流式细胞仪检测细胞周期变化及细胞凋亡率;倒置显微镜观察细胞形态变化.结果 SMMC-7721可强表达survivin mRNA和蛋白;ASODN呈浓度依赖性抑制survivin mRNA和蛋白表达及SMMC-7721增殖,诱导细胞凋亡,使细胞阻滞于G2/M期.SODN对survivin mRNA和蛋白及SMMC-7721的增殖、细胞周期无明显抑制作用.结论 脂质体介导转染survivin ASODN可抑制细胞增殖、使细胞阻滞于G2/M期,从而促进细胞凋亡.     

热疗对膀胱癌BIU-87细胞凋亡和生存素表达的影响

目的探讨热疗对膀胱癌BIU-87细胞凋亡和生存素（survivin）表达的影响。方法不同温度条件下热疗作用膀胱癌细胞株BIU-87后,用MTT法检测细胞增殖,流式细胞仪检测细胞周期、细胞凋亡和survivin表达的变化。结果热疗可以抑制BIU-87细胞增殖,减少survivin表达,诱导BIU-87凋亡,SubG0/G1期细胞百分比增多,并均呈温度依赖性（P〈0.05）。结论热疗可诱导BIU-87细胞凋亡,下调survivin表达,且呈温度依赖性。     

重组核心蛋白聚糖转染对HepG2细胞周期、凋亡以及P21表达的影响

目的将已构建完成的分泌型核心蛋白聚糖（DCN）真核表达载体转染到HepG2中并检测其表达同时研究其抗肿瘤作用的机制。方法脂质体介导分泌型DCN真核表达载体转染HepG2细胞，经G418筛选建立稳定转染的细胞株，采用RT-PCR、免疫组化检测其表达。MTT检测细胞增殖活力，流式细胞仪分析细胞周期，RT-PCR方法检测P21^WAF1/CIP1mRNA表达情况。结果RT-PCR可见转染组细胞DCNmRNA表达明显增多，免疫组化可见转染组细胞DCN蛋白表达明显增高。细胞生长曲线显示转染组细胞生长缓慢；G1期细胞显著增多；P21^WAF1/CIP1mRNA表达增高。结论本研究成功建立稳定转染DCN的HepG2细胞株，证实DCN通过阻滞细胞周期、诱导细胞凋亡和提高P21^WAF1/CIP1蛋白抑制HepG2的生长。     

节律基因Bmal1对胃癌细胞BGC-823增殖及凋亡的影响

目的 探讨节律基因Bmal1对胃癌细胞BGC-823增殖及凋亡的影响.方法 构建针对Bmal1序列的shRNA,用脂质体介导转染入胃癌细胞BGC-823,G418筛选稳定细胞株(转染组),同时设对照组(空白组).用克隆形成率检测细胞生长,用流式细胞术检测细胞凋亡及细胞周期,RT-PCR及Western blot法检测相关基因及蛋白表达.结果 转染组克隆形成率低于对照组(P＜0.05).与对照组比较,转染组Bmal1总凋亡率升高(P＜0.05),其细胞周期再分布出现G1期缩短(P＜0.05),G2期延长(P＜0.05),同时发现Bcl-2 mRNA表达下调(P＜0.05),c-Myc mRNA表达上调(P＜0.05).结论 Bmal1可以抑制胃癌细胞BGC-823增殖,促进细胞凋亡,有可能成为诱导胃癌细胞凋亡的新靶点.     

粉防己碱对大鼠静止期肝星状细胞细胞周期的影响

目的观察粉防己碱对大鼠静止期肝星状细胞（HSCs）细胞周期的影响及机制。方法分离正常大鼠HSCs,培养48 h后给予粉防己碱（1.6μmol/L）和（或）TGF-β1（5μg/L）处理3 d。流式细胞仪检测细胞周期分布;应用RT-PCR法检测Cyclin D1、Cyc-lin E、p21WAF1/CiP1和p27Kip1表达;使用Western blot法检测Cyclin D1和PPARγ蛋白水平。结果粉防己碱使G0/G1期和G2/M期细胞增多,S期细胞数显著减少,抑制TGF-β1介导的G0/G1期细胞含量下调和S期细胞含量升高,上调p21WAF1/CiP1mRNA表达,抑制Cyclin D1而维持PPARγ蛋白在一定水平。结论在静止期HSC中,粉防己碱通过抑制Cyclin D1、上调p21WAF1/CiP1和维持PPARγ表达使HSCs出现G0/G1期停滞和S期向G2/M期转换加速。     

氧化苦参碱对人结肠癌细胞株SW1116细胞周期通路相关调控因子的影响

背景：氧化苦参碱为中药苦参的主要有效成分，研究显示其对结肠癌细胞具有杀伤作用。目的：观察氧化苦参碱对人结肠癌细胞株SW1116细胞周期通路相关调控因子的影响，阐明其抗结肠癌作用的分子机制。方法：分别以2、3、4mg／m1氧化苦参碱干预SW1116细胞24h或48h，以流式细胞仪检测细胞周期，以逆转录聚合酶链反应（RTPCR）和蛋白质印迹法检测细胞周期蛋白（cyclin）D1、细胞周期蛋白依赖性激酶4（CDK4）、CDK抑制剂p53、核转录岗子E2F1和S期激酶相关蛋白2（Skp2）mRNA和蛋白水平的表达。结果：氧化苦参碱干预可使SW1116细胞周期阻滞于G0／G1期，cyc1inD1、CDK4、E2F1和Skp2mRNA和蛋白表达显著下降，p53mRNA和蛋白表达显著上升，作用呈剂量和时间依赖性（P〈0．05）。结论：氧化苦参碱可通过影响细胞周期相关通路以抑制人结肠癌细胞增殖。     

Regulation of apoptosis at cell division by p34cdc2 phosphorylation of survivin

The interface between apoptosis (programmed cell death) and the cell cycle is essential to preserve homeostasis and genomic integrity. Here, we show that survivin, an inhibitor of apoptosis over-expressed in cancer, physically associates with the cyclin-dependent kinase p34(cdc2) on the mitotic apparatus, and is phosphorylated on Thr(34) by p34(cdc2)-cyclin B1, in vitro and in vivo. Loss of phosphorylation on Thr(34) resulted in dissociation of a survivin-caspase-9 complex on the mitotic apparatus, and caspase-9-dependent apoptosis of cells traversing mitosis. These data identify survivin as a mitotic substrate of p34(cdc2)-cyclin B1 and suggest that survivin phosphorylation on Thr(34) may be required to preserve cell viability at cell division. Manipulation of this pathway may facilitate the elimination of cancer cells at mitosis.     

丹参酮ⅡA对人胰腺癌细胞凋亡的诱导作用及其对SAPK/JNK信号转导通路的影响

目的:研究丹参酮ⅡA诱导人胰腺癌细胞凋亡和凋亡相关基因表达的JNK信号转导通路,揭示其抗胰腺癌的部分机制.方法:MTT法观察丹参酮ⅡA对人胰腺癌PANC-1细胞的生长抑制作用;8、16、32 mg/L丹参酮ⅡA分别作用人胰腺癌PANC-1细胞48 h后,免疫荧光染色观察细胞凋亡情况;流式细胞仪法(FCM)检测细胞凋亡;...     

p53-dependent G1 arrest involves pRB-related proteins and is disrupted by the human papillomavirus 16 E7 oncoprotein.

The cell cycle regulatory tumor suppressor proteins p53 and pRB are targeted for inactivation by several tumor viruses, including the high-risk types of human papillomaviruses (HPVs) via interactions of the HPV E6 and E7 oncoproteins with p53 and pRB, respectively. p53 plays a central role in a signal transduction pathway that mediates G1 arrest after DNA damage, though the mechanism by which G1 arrest occurs has not been elucidated. The cyclin-associated protein p21waf1/cip1 has recently been shown to be induced by p53 and to inhibit cyclin complex-mediated phosphorylation of pRB in vitro. Thus, we investigated a possible role for pRB in the p53-mediated DNA damage response. After gamma-irradiation, cells expressing wild-type p53 arrested in G1, contained increased levels of WAF1/CIP1 mRNA, and demonstrated accumulation of hypophosphorylated pRB. In contrast, cell lines with abnormal p53 genes or with p53 functionally inactivated by the E6 oncoprotein of HPV16 (a high-risk HPV) failed to arrest in G1, did not elevate WAF1/CIP1 mRNA, and did not accumulate hypophosphorylated pRB. Despite apparently normal elevation of p53 protein and WAF1/CIP1 mRNA after irradiation, cells expressing HPV16 E7 also failed to arrest in G1 and did not accumulate hypophosphorylated pRB. Disruption of RB genes alone did not totally abrogate this G1 arrest. Our results suggest that p53 indirectly regulates phosphorylation of pRB and that pRB and/or other pRB-like molecules that bind to HPV16 E7 participate in the DNA damage-mediated G1 arrest signal. In the process of HPV infection, the HPV E6 and E7 oncoproteins may undermine this cell cycle checkpoint, contributing to the accumulation of genetic alterations during tumorigenesis.     

P16 reactivation induces anoikis and exhibits antitumour potency by downregulating Akt/survivin signalling in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the most malignant tumours with high rate of recurrence and metastasis. In HCC, deficiency of the P16/CDK4/Rb pathway is a frequent molecular event, and transferring the P16 gene into cancer cells can induce cell cycle arrest and apoptosis, suggesting that the P16 gene is a good target in cancer gene therapy. The previous study demonstrated that P16 re-expression mediated by adenovirus within cancer cells can induce cell apoptosis and exert potent antitumour efficacy in cancer xenografts in nude mice. However, the molecular mechanism of P16-induced apoptosis in cancer cells is not clear yet. In this resulting study, we found that P16 re-expression can downregulate survivin expression in HCC cells. As a member of the inhibitors of the apoptotic gene family, survivin has been reported to be overexpressed in most common human cancers and present multiple physiological and pathological functions including cell cycle control, inhibition of cell apoptosis, regulation of cell division and induction of angiogenesis, etc. Further investigation found that P16 reactivation led to a decrease of phosphorylated Akt on Thr308 and phosphorylated survivin on Thr34, then downregulated survivin expression. The P16-mediated decrease of nuclear survivin in cancer cells limited CDK4 import into nuclei, which restrained CDK4 functions of promoting cell proliferation, then exhibited the effect of cell cycle arrest and induction of detachment-induced apoptosis (anoikis). The antitumor potency of P16 by downregulating the Akt/survivin signalling was also demonstrated in HCC xenograft models in nude mice. This new insight into P16 function would help in designing better strategies for cancer gene therapy.     

Novel nonclassical antifolate, 2-[N-(2´-Hydroxyethyl)amino]methyl-3H-quinazolin-4-one, with a potent antineoplastic activity toward leukemia cells

This study was aimed to investigate the therapeutic potential of novel nonclassical antifolate, 2-[N-(2′-Hydroxyethyl)ami-no]methyl-3H-quinazolin-4-one (HEAMQ), toward human promonocytic U937 and murine lymphoblastic L1210 cell lines. The antiproliferative activity of HEAMQ was determined by MTT assay and its effects on cell cycle progression and apoptosis were studied by flow cytometry, and by immunoblots, respectively. In addition, combination chemotherapy of HEAMQ with cisplatin and temozolomide under in vitro and in vivo conditions was tested. HEAMQ showed concentration- and time-dependent cytotoxicity toward U937 and L1210 cells. It induced G2/M arrest that in U937 cells was associated with a marked decrease in the protein expressions of cyclin A, cyclin B, and cyclin-dependent kinase Cdk1. HEAMQ-induced apoptosis was accompanied with up-regulation of the protein expression of Bax and down-regulation of the protein expression of Bcl-2, Mcl-1, XIAP, and survivin, resulting in cytochrome c release and activation of caspases. Inhibitors of JNK (SP600125) and p38 MAPK (SB203580) suppressed HEAMQ-induced apoptosis and G2/M phase arrest, attenuated the activation of Bax, and blocked down-regulation of Bcl-2, XIAP and survivin in HEAMQ-treated U937 cells. In addition, combinations of HEAMQ with cisplatin and temozolomide resulted in synergistic inhibition of cell growth, producing long-term survivors of L1210 tumor-bearing mice. In conclusion, these results indicate that HEAMQ antineoplastic activity toward leukemia cells is associated with cell cycle arrest and apoptosis. The in vivo studies further confirmed the antitumor activity of HEAMQ and highlighted that this agent could be used to further increase therapeutic efficacies of traditional chemotherapeutic agents. Keywords: nonclassical antifolate, quinazolinone, antineoplastic, apoptosis, cell cycle arrest, synergism.     

Arsenic trioxide induces apoptosis in pancreatic cancer cells via changes in cell cycle,caspase activation,and GADD expression

We have previously shown that arsenic trioxide blocks proliferation and induces apoptosis in human pancreatic cancer cells at low, non-toxic concentrations. The mechanisms of the apoptosis was investigated in MiaPaCa2 and PANC-1 cells that have been previously shown to be responsive to arsenic trioxide. The results show the caspase-3, caspase-7, and caspase-9 are all activated by arsenic trioxide, together with cleavage of the downstream caspase-3 target poly ADP ribose polymerase (PARP). Expression of the anti-apoptosis proteins, Bcl-2 and Mcl-1 expression decreased time-dependently while Bax expression increased. These findings indicate that the Bcl family of proteins, the mitochondrial pathway and activation of the caspase cascade are responsible for arsenic-induced apoptosis. Flow cytometric analysis revealed changes of cell cycle distribution from a G0/G1 phase arrest at 24 hours to G2/M phase arrest at 72 hours following arsenic treatment. The sub-G0/G1 cell population of apoptotic cells was increased at these times. Arsenic increased expression of the P21 protein and decreased levels of cyclin A, cyclin B1 and cyclin D1, but expression of CDK2, CDK4, CDK6, and cyclin E were not affected. Arsenic trioxide markedly enhanced the expression of GADD45 and GADD153 in a time-dependent manner. In summary, arsenic trioxide induced apoptosis in pancreatic cancer cells through activating the caspase cascade via the mitochondrial pathway, GADD expression and by modifying cell cycle progress and changes in several cycle-regulating proteins. This old drug may be valuable for treatment of pancreatic cancer.