PUMA基因在肿瘤治疗方面的研究进展

p53上调凋亡调控因子(PUMA)是近年发现的Bcl-2家族成员,因其可被p53快速诱导并具有强大促凋亡作用而在生命科学的研究领域受到广泛关注.PUMA不仅能够诱导多种肿瘤细胞凋亡,抑制肿瘤细胞增殖,还能增加肿瘤细胞对放化疗的敏感性,是非常有前景的肿瘤基因治疗靶点.也有新的研究发现PUMA还在肿瘤发生过程中承担着更多的...     

Down-regulation of stathmin is required for TGF-beta inducible early gene 1 induced growth inhibition of pancreatic cancer cells

Transforming growth factor-beta (TGF-beta) inducible early gene 1 (TIEG1) is known to induce apoptosis in TGF-beta sensitive pancreatic cancer cells, yet its effect on TGF-beta resistant cancer cells remains unclear. In this study, TIEG1 was found to induce apoptosis in TGF-beta resistant cancer cells and concurrently enhanced gemcitabine chemosensitivity. Down-regulation of stathmin was noted to associate with TIEG1 expression, whilst ectopic overexpression of stathmin prevented TIEG1 mediated growth inhibition of tumor cells. Small interfering RNAs targeting stathmin inhibited pancreatic cancer cell growth. These suggest that stathmin is a downstream target of TIEG1.     

miR-762在胰腺癌中的表达及对胰腺癌细胞生物学行为的影响

背景与目的：miR-762在多种恶性肿瘤中存在表达异常,参与肿瘤的增殖、凋亡及侵袭转移。观察miR-762在胰腺癌组织和细胞系中的表达及对胰腺癌细胞增殖、侵袭转移的影响。方法：采用实时荧光定量聚合酶链反应（real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR）技术检测于河北医科大学第四医院行胰腺癌根治术的胰腺癌组织和细胞株中miR-762的表达。通过Lipofectamine ^TM 2000将miR-762模拟物（mimics）、miR-762抑制物（inhibitors）及其阴性对照序列（scramble序列）分别转染胰腺癌PANC-1细胞。采用细胞计数试剂盒（cell counting kit-8,CCK-8）实验检测细胞增殖;采用流式细胞术检测细胞凋亡;采用划痕实验和Transwell侵袭实验检测细胞侵袭转移能力;采用蛋白质印迹法（Western blot）检测上皮-间质转化（epithelial-mesenchymal transformation,EMT）相关分子标志物表达。结果：胰腺癌组织中miR-762 mRNA表达量显著高于癌旁组织（P<0.01）。胰腺癌细胞株BxPC-3、PANC-1、AsPC-1、SW-1990中miR-762 mRNA的表达量也显著高于正常胰腺上皮细胞HPDE（P<0.01）。转染miR-762 mimics后PANC-1细胞miR-762 mRNA表达量显著增加,而转染miR-762 inhibitors后PANC-1细胞miR-762 mRNA表达量显著降低（P<0.01）。同时miR-762 mimics组450 nm处的吸光度（D ₄₅₀ ）值、细胞迁移距离和穿膜细胞数及间质表型细胞标志物N-钙黏蛋白（N-cadherin）、波形蛋白（vimentin）表达量显著增加,细胞凋亡率及上皮细胞标志物E-钙黏蛋白（E-cadherin）表达量显著降低;而miR-762inhibitors组D ₄₅₀ 、细胞迁移距离和穿膜细胞数及间质表型细胞标志物N-cadherin、vimentin表达量显著降低,细胞凋亡率及上皮细胞标志物E-cadherin表达量显著增加（P<0.05）。结论：miR-762在胰腺癌组织和细胞株中高表达,上调miR-762表达可能通过调控N-cadherin、vimentin、E-cadherin表达促进EMT进程,从而增强PANC-1细胞的增殖和侵袭转移能力。     

PKLR在胰腺癌中的表达水平及临床病理学意义

背景与目的:胰腺癌是一种原发于消化系统的恶性肿瘤,发病率男性高于女性,且患者预后差.重组人丙酮酸激酶(pyruvate kinase isozymes R/L,PKLR)属于丙酮酸激酶家族,哺乳动物丙酮酸激酶同工酶有4种:L、R、M1和M2,其与肿瘤的发生、发展密切相关.已经有研究发现,PKLR会促进乳腺癌的转移.探究...     

锰超氧化物歧化酶过表达对食管癌TE-1细胞增殖及移植瘤生长的双向影响

目的:通过体内外实验探讨锰超氧化物歧化酶(manganese superoxide dismutase,MnSOD)过量表达对食管癌TE-1细胞增殖的影响。方法:采用病毒感染法将不同剂量构建有MnSOD基因的重组质粒转入食管癌TE-1细胞,建立中、高表达MnSOD的TE-1细胞pLenti6-mMnSOD/TE-1(TE-1Mm)和pLenti6-hMnSOD/TE-1(TE-1Mh);采用RT-PCR法及Western印迹法检测转染MnSOD重组质粒的TE-1细胞中mRNA和蛋白水平的表达变化情况;应用平皿克隆形成实验及FCM法观察细胞增殖、凋亡和周期变化的情况;将MnSOD转染后的TE-1细胞接种到裸鼠皮下检测成瘤及肿瘤生长情况,采用免疫组织化学和Western印迹法检测移植瘤中MnSOD蛋白的表达水平。结果:建立稳定表达MnSOD蛋白的TE-1细胞株;RT-PCR及Western印迹法检测结果均证实,感染不同剂量的MnSOD重组质粒的TE-1细胞中,MnSOD的表达水平随感染剂量的增加而上升;细胞平皿克隆检测结果提示,TE-1Mm和TE-1Mh细胞的集落形成能力为(23.0±2.7)%和(45.3±4.5)%,分别低于和高于TE-1细胞的(34.7±4.2)%及TE-1n细胞的(33.7±4.7)%,实验组间比较及与对照组进行比较,差异均有统计学意义(P<0.05);AnnexinV-PI双染FCM检测结果显示,TE-1Mm和TE-1Mh细胞的早期细胞凋亡率为(10.6±1.0)%和(1.0±0.1)%,分别高于和低于对照组TE-1细胞的(2.6±0.2)%和TE-1n细胞的(2.5±0.3)%(P<0.05);细胞周期检测结果显示,MnSOD过量表达使G0/G1期细胞数在TE-1Mm细胞中增多,而在TE-1Mh细胞中减少,G2/M期和S期细胞数则在TE-1Mm细胞中减少,在TE-1Mh细胞中增多;与亲本TE-1细胞和感染空载体TE-1n细胞相比,TE-1Mm细胞处在增殖期细胞少,而TE-1Mh细胞处在增殖期细胞多(P<0.05)。TE-1Mm细胞接种裸鼠后,肿瘤生长慢,体积小,而接种TE-1Mh细胞则相反,肿瘤生长速度明显加快;瘤组织中的MnSOD蛋白的表达水平,与对照组比较差异均有统计学意义(P<0.05)。结论:MnSOD过量表达通过改变细胞周期和凋亡,对食管癌TE-1细胞的增殖和移植瘤的生长均表现为促进和抑制增殖的双向作用。     

RNA干扰沉默DcR3对人胰腺癌细胞化疗药物敏感性影响的实验研究

背景与目的：大部分胰腺癌具有高表达诱骗受体-3(decoy receptor 3,DcR3)的特征,而后者与FasL凋亡途径相关,可能导致胰腺癌对化疗耐药。该研究旨在探讨RNA干扰沉默DcR3基因对人胰腺癌细胞化疗药物敏感性的影响及其可能机制。方法：构建带有DcR3-siRNA序列的稳定表达质粒,通过Lipofectamine^TM2000转染至人胰腺癌细胞AsPC-1细胞株,筛选出转染后稳定低表达DcR3的胰腺癌细胞,同时设未转染对照组(control组)和转染阴性质粒对照组(mock组)。应用ELISA和蛋白［质］印迹法(Western blot)检测各组AsPC-1细胞中DcR3的蛋白表达;MTT实验检测各组AsPC-1细胞对吉西他滨的敏感性;流式细胞术检测各组AsPC-1细胞凋亡情况;Western blot和实时荧光定量聚合酶链反应(real-time fluorescent quantitative polymerase chain reaction,RTFQ-PCR)检测各组AsPC-1细胞中FasL、Caspase-8、Caspase-3蛋白和mRNA的表达。结果：转染DcR3-siRNA后AsPC-1细胞中DcR3蛋白较其他对照组明显降低;转染DcR3-siRNA后AsPC-1细胞对吉西他滨的敏感性显著增加;沉默DcR3基因可以上调FasL、Caspase-8和Caspase-3的表达并促进吉西他滨诱导的细胞凋亡。结论：RNA干扰沉默DcR3基因可激活FasL/Caspase凋亡途径,促进肿瘤细胞凋亡,增加人胰腺癌AsPC-1细胞对化疗药物的敏感性。     

CDC25B1对人胰腺癌细胞株Patu8988的生物学行为的影响

目的 探讨CDC25B1基因在人胰腺癌细胞株Patu8988中的表达情况,并将真核表达重组载体pcDNA-CDC25B1转染至细胞中,观察CDC25B1基因对细胞生物学行为的影响,以了解它在细胞周期及胰腺肿瘤细胞恶性转化方面的作用,为研究胰腺癌的发病机制与治疗提供理论依据.方法 利用Lipolectamine2000将CDC25B1转染至人胰腺癌细胞株Patu8988中,通过RT-PCR和Western blot在mRNA和蛋白水平验证质粒转染成功,通过MTT实验、侵袭实验和细胞周期检测,观察CDC25B1对细胞生物学行为的影响. 结果 RT-PCR发现在胰腺癌细胞株Patu8988和转染空质粒的细胞株中,CDC25B1在mRNA水平表达很弱;转染pcDNA-CDC25B1组中CDC25B1高表达.Western blot发现在胰腺癌细胞株Patu8988中,CDC25B蛋白有少量表达;转染pcDNA-CDC25B1组CDC25B蛋白高表达.MTT实验显示,转染pcDNA-CDC25B1组的细胞生长在72 h受到明显抑制(P<0.05).侵袭实验显示,转染pcDNA-CDC25B1的细胞其穿透Matrigel胶的能力明显增强(P<0.05).流式细胞计量术显示,转染了pcDNA-CDC25B1组中,G1期的细胞明显增多(P<0.05);同时转染了pcDNA-CDC25B1组中,G2期的细胞明显减少,与未处理组比较有统计学意义(P<0.05). 结论 在胰腺癌细胞株Patu8988中的CDC25B1转录水平很弱,存在少量CDC25B蛋白表达.转染的CDC25B1基因提高CDC25B1蛋白的表达,使细胞停滞在G1期,对细胞的生长有抑制作用,但能够增强细胞的侵袭能力;CDC25B1可能不是通过单一的调控细胞周期而实现其对细胞的影响,还存在其它多种途径.     

PUMA基因转染乳腺癌MCF-7细胞增强表柔比星致凋亡敏感性的研究

  目的  探讨PUMA基因转染是否增强乳腺癌MCF-7细胞对表柔比星致凋亡的敏感性。   方法  应用脂质体介导重组真核表达载体PUMA-pCDNA3和空载体pCDNA3质粒瞬时转染至乳腺癌MCF-7细胞中, G418筛选阳性细胞。将系列浓度(0.01~100μmol/L)的表柔比星分别作用于MCF-7、MCF-7/PUMA和MCF-7/pCDNA3细胞72 h, MTT法测定各组细胞的存活率并计算IC50, FCM、TUNEL法检测细胞凋亡情况, Western blotting检测各组细胞PUMA蛋白表达的变化。   结果  MCF-7、MCF-7/PUMA和MCF-7/pCDNA3细胞的表柔比星IC50分别为(13±1.4)、(1.8±0.2)和(10.7±1.3)μmol/L, MCF-7/PUMA细胞对表柔比星作用的敏感性增加了7.2倍。表柔比星以剂量依赖方式诱导MCF-7细胞凋亡, 但对MCF-7/PUMA细胞所诱导的凋亡比MCF-7和MCF-7pCDNA3更明显。低浓度表柔比星(0.1μmol/L)轻微引起MCF-7/pCDNA3[(1.15±0.26)%]和MCF-7细胞凋亡[(0.9±0.24)%], 但能诱导MCF-7/PUMA细胞明显凋亡[(6.44±1.46)%]; 高浓度表柔比星(1μmol/L)诱导各组细胞凋亡, 但表柔比星MCF-7/PU MA细胞凋亡率[(35.47±9.36)%]明显高于MCF-7[(12.6±3.73)%]和MCF-7/pCDNA3细胞[(15.2±5.17)%], 差异均有统计学意义(P < 0.01);FCM和TUNEL方法检测显示相同的结果。PUMA蛋白在MCF-7/PUMA细胞中的表达明显高于MCF-7和MCF-7/pCD NA3细胞。   结论  PUMA基因稳定转染明显地增强了乳腺癌MCF-7细胞增强表柔比星致凋亡作用的敏感性。      

细胞凋亡在胰腺癌治疗中的作用

胰腺癌（ Pancreatic adenocarcinoma ,PAC）由于发病因素多、病情隐匿不易诊断、对放化疗不敏感而导致预后极差。细胞凋亡信号通路阻断可能是导致胰腺癌对传统放化疗不敏感的关键原因。本综述拟梳理胰腺癌细胞内部凋亡失衡主要信号通路,总结细胞凋亡诱导关键信号通路等在胰腺癌治疗中的基础研究进展,以期为拓展胰腺癌细胞凋亡的理解和开发凋亡相关靶向分子治疗提供新思路。     

RGD偶联吉西他滨白蛋白纳米粒对胰腺癌细胞周期和凋亡的影响

背景与目的:吉西他滨作为目前临床胰腺癌一线用药,由于其化疗耐药性,化疗效果较差。本研究通过制备RGD偶联吉西他滨白蛋白纳米粒,通过增加其靶向性,探讨其对胰腺癌细胞株BxPC-3和PANC-1细胞周期和凋亡的影响。方法:以人胰腺癌细胞株BxPC-3(高表达αvβ3受体)和PANC-1(低表达αvβ3受体)为研究对象,各分为6个给药组:对照组、BSANP(白蛋白纳米粒)、RGD-BSANP组、BSANP-GEM组、GEM原药组(吉西他滨)、RGD-BSANP-GEM组。运用PI单染检测给药后24 h细胞周期的变化,Annexin V/PI双染色法检测细胞凋亡。结果:在BxPC-3细胞株中,与BSANP-GEM组及GEM组相比,RGD-BSANP-GEM组S期细胞比例明显下降,G0/G1期细胞比例明显增多,且在RGD-BSANP-GEM组凋亡率最高;而在PANC-1细胞中,RGD-BSANP-GEM组G0/G1期细胞阻滞的比例和凋亡率低于BxPC-3细胞株。结论:RGD环肽能够增加BSANP-GEM对高表达αvβ3胰腺癌BxPC-3细胞G0/G1期阻滞及细胞凋亡。     

EGFR and EGFRvIII interact with PUMA to inhibit mitochondrial translocalization of PUMA and PUMA-mediated apoptosis independent of EGFR kinase activity

EGFR and its constitutively activated variant EGFRvIII are linked to glioblastoma resistance to therapy, the mechanisms underlying this association, however, are still unclear. We report that in glioblastoma, EGFR/EGFRvIII paradoxically co-expresses with p53-upregulated modulator of apoptosis (PUMA), a proapoptotic member of the Bcl-2 family of proteins primarily located on the mitochondria. EGFR/EGFRvIII binds to PUMA constitutively and under apoptotic stress, and subsequently sequesters PUMA in the cytoplasm. The EGFR–PUMA interaction is independent of EGFR activation and is sustained under EGFR inhibition. A Bcl-2/Bcl-xL inhibitor that mimics PUMA activity sensitizes EGFR/EGFRvIII-expressing glioblastoma cells to Iressa. Collectively, we uncovered a novel kinase-independent function of EGFR/EGFRvIII that leads to tumor drug resistance.     

沉默ANO9增加胰腺癌细胞AsPC-1放射敏感性的实验研究

目的 探讨ANO9对胰腺癌细胞AsPC-1放射敏感性的影响,以期为胰腺癌临床放射治疗提供新的增敏靶点。方法 蛋白印迹法检测胰腺癌细胞系(BxPC-3、PANC-1、AsPC-1)和正常胰腺细胞系中ANO9表达水平;慢病素感染构建沉默ANO9的AsPC-1稳转株,并用蛋白印迹法进行验证;MTT检测沉默ANO9对放射照射后AsPC-1细胞活力的影响;平板克隆形成实验检测沉默ANO9对AsPC-1细胞放射敏感性的影响;蛋白印迹法检测沉默ANO9对EGFR/ERK信号蛋白表达的影响。结果 与正常胰腺细胞系相比,3个胰腺癌细胞系中ANO9表达均增加(均P<0.05);沉默ANO9后细胞中ANO9蛋白表达水平较对照组显著降低(P<0.05),成功构建沉默ANO9的AsPC-1稳转株;沉默ANO9后AsPC-1细胞对放射照射的敏感性明显增加,放射增敏比为1.57,细胞中EGFR/ERK信号蛋白EGFR和p-ERK1/2均下调(均P<0.05)。结论 沉默ANO9能够显著增加胰腺癌细胞AsPC-1的放射敏感性,其机制可能与抑制EGFR/ ERK信号转导有关,ANO9可能成为遏制胰腺癌进展的新靶标。     

Mechanisms of TRAIL and gemcitabine induction of pancreatic cancer cell apoptosis

The aim of this study was to investigate induction of apoptosis by the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and gemcitabine in the pancreatic cancer cell line SW1990. The sensitivity of SW1990 cells to TRAIL and/or gemcitabine-induced apoptosis and the rate of apoptosis were assessed by MTT assay and flow cytometry, respectively. We used Hoechst 33342 staining to observe apoptotic morphology and expression levels of proteins were analyzed by Western blottin. Growth inhibition and apoptosis rates on treatment with the combination of TRAIL and gemcitabine were significantly higher than with each drug alone (p<0.05). Pancreatic cancer cells exhibited a typical apoptosis morphology after treatment with TRAIL or gemcitabine. The levels of cellular apoptosis-associated proteins such as Smac/DIABLO, Cyto C, and the activated fragment of caspase-3 (P17) increased, but the expression of XIAP was significantly decreased after 24 h (p<0.05). SW1990 cells responded to TRAIL and/or gemcitabine-induction of apoptosis in a time and concentration-dependent manner. The mechanism of the apoptosis-sensitization effect appeared associated with significant up-regulation of Smac/DIABLO and cytochrome C, down-regulation of XIAP, and activation of caspase-3.     

斑蝥酸钠对结肠癌HCT116细胞凋亡及PUMA表达的影响

目的 探讨斑蝥酸钠对结肠癌细胞凋亡及p53上调凋亡控制因子（PUMA）表达的影响。方法 采用不同浓度斑蝥酸钠（0.1、0.25、0.5、1、2 μg／ml）处理结肠癌细胞HCT116 24 h,并设不加药对照组。测量其单层细胞跨膜电阻值（TER）以评价斑蝥酸钠对HCT116细胞凋亡的影响,同时采用实时荧光定量PCR和Western blotting分别检测HCT116细胞的PUMA mRNA和蛋白水平变化;HCT116细胞经0.05、0.1、0.2、0.4、0.8 μg／ml 抑制性κB激酶β（IKKβ）质粒转染或10、20、40、80 nmol／L 核因子（NF）-κB抑制剂（BAY 11-7082）处理后,采用Western blotting检测其PUMA蛋白水平。结果 与对照组比较,各浓度斑蝥酸钠处理后HCT116细胞的TER降低,PUMA mRNA和蛋白水平升高,且以上效应呈浓度依赖性,差异有统计学意义（P＜0.05）;与未处理的HCT116细胞相比,IKKβ质粒转染后,PUMA蛋白表达增加,而BAY 11-7082可降低斑蝥酸钠对PUMA的上调作用,差异有统计学意义（P＜0.05）。结论 斑蝥酸钠可通过NF-κB通路上调PUMA的表达,进一步诱导结肠癌细胞HCT116的凋亡。     

NS-398和罗格列酮协同诱导胰腺癌细胞凋亡的研究

目的探讨特异性环氧合酶-2（COX-2）抑制剂NS-398和过氧化物酶体增殖因子活化受体（PPAR）γ激动剂罗格列酮对人胰腺腺癌细胞株SW1990细胞凋亡的调控作用及其机制。方法SW1990细胞接种于含10%胎牛血清的DMEM液中,常规培养24 h后加NS-398（150μmol/L）和（或）罗格列酮（50μmol/L）,连续培养48 h。采用流式细胞仪检测细胞凋亡率,逆转录-聚合酶链反应（RT- PCR）法检测凋亡抑制基因Bcl-2 mRNA表达。结果NS-398组、罗格列酮组和联合用药组的细胞凋亡率分别为（10.65±3.93）%、（14.51±2.36）%和（25.87±5.24）%,显著高于对照组的（3.12±1.76）% （P〈0.05和P〈0.01）,联合用药组的细胞凋亡率明显高于NS-398或罗格列酮单一用药组（P〈0.01）。NS-398和罗格列酮显著下调Bcl-2 mRNA在SW1990细胞的表达（P〈0.01）。结论NS-398、罗格列酮通过下调Bcl-2基因表达而诱导细胞凋亡,两者联合使用具有协同作用。     

Phosphorylation status of heat shock protein 27 plays a key role in gemcitabine-induced apoptosis of pancreatic cancer cells

Gemcitabine, an antitumor drug, is currently considered to be the standard of care for the treatment of advanced pancreatic cancer, but the clinical outcome is still not satisfactory. Although heat shock protein (HSP) 27 is implicated in the resistance to chemotherapy in several types of cancers, the precise role of phosphorylated HSP27 in cancer cells remains to be clarified. In this study, we investigated the relationship between the effect of gemcitabine and the phosphorylation status of HSP27 in pancreatic cancer cells, Panc1 and KP3. Gemcitabine suppressed pancreatic cancer cell growth and induced apoptosis. Gemcitabine caused activation of p38 mitogen-activated protein kinase (MAPK), MAPK-activated protein kinase 2 (MAPKAPK-2) and subsequently phosphorylation of HSP27 at Ser15, 78 and 82 without affecting total HSP27 levels. The inhibitions of p38 MAPK and MAPKAPK-2 reduced the phosphorylation of HSP27 and apoptosis in gemcitabine-treated cells. To further investigate the role of phosphorylated HSP27, we established Panc1 cell lines which were stably transfected with empty vector (empty cells), wild-type HSP27-encoding vector (WT cells) and 2 mutant HSP27-encoding vectors that mimic non-phosphorylated (3A), and phosphorylated (3D), respectively. In comparison of empty cells with WT cells, there was no difference in cell growth rate and the sensitivity to gemcitabine. Interestingly, cell growth of 3D cells was retarded as compared to that of 3A cells. Taken together, our results strongly suggest that phosphorylation status of HSP27 plays a key role in gemcitabine-induced growth suppression of pancreatic cancer.     

Anti-cancer effect of HS-345, a new tropomyosin-related kinase A inhibitor,on human pancreatic cancer

Tropomyosin-related kinase A (TrkA) is emerging as an important player in carcinogenic progression. TrkA overexpression, which is associated with cell growth, proliferation, survival, and invasion, has been observed in pancreatic cancer. We therefore synthesized HS-345, a novel TrkA inhibitor, and evaluated its anti-cancer effect and underlying mechanism of action in pancreatic cancer. In this study, HS-345 effectively inhibited the growth and proliferation in three pancreatic cancer cell lines (PANC-1, MIA PaCa-2, and BxPC-3). Activation of the TrkA/Akt signal cascade was also inhibited by HS-345 treatment in a dose-dependent manner. The pro-apoptotic effect of HS-345 was evidenced by increased levels of cleaved caspase-3 and cleaved PARP, and decrease of Bcl/Bax expression via mitochondria membrane potential, as well as elevated numbers of TUNEL-positive apoptotic cells. HS-345 was additionally found to exert anti-angiogenic effect by decreasing the expression of HIF-1α and VEGF, major factors of angiogenesis, which were also demonstrated by the suppression of tube formation and migration of VEGF-treated human umbilical vein endothelial cells along with inhibition of blood vessel formation by HS-345 in a Matrigel plug assay with mice. Results of our investigation show that HS-345 inhibited the TrkA/Akt signaling pathway resulting in cell growth/angiogenesis inhibition and apoptosis induction. Based on our data, we suggest that HS-345 is a potential candidate for treating pancreatic cancer.     

BTG1对喉癌细胞增殖和凋亡的影响及其机制研究

背景与目的：在多种细胞中B细胞易位基因1(B-cell translocation gene 1,BTG1)能够抑制细胞增殖,促进细胞凋亡,调节细胞周期进程及分化。该研究通过体外实验探讨BTG1高表达对喉癌Hep-2细胞增殖、凋亡及细胞周期的影响及其相关作用机制。方法：构建pEGFP-N1-BTG1,培养并转染喉癌Hep-2细胞,分为实验组(转染pEGFP-N1-BTG1的Hep-2细胞)和对照组(转染pEGFP-N1空质粒的Hep-2细胞)。采用蛋白［质］印迹法(Western blot)检测两组细胞中BTG1蛋白的表达水平;应用MTT法检测细胞的增值活性;使用流式细胞术检测细胞周期分布和磷脂酰丝氨酸外翻分析(Annexin Ⅴ-FITC/PI)检测细胞凋亡;采用Western blot法检测细胞周期调控蛋白Cyclin D1、凋亡相关蛋白Bcl-2表达情况。结果：成功构建pEGFP-N1-BTG1,Western blot检测结果显示,实验组细胞中BTG1蛋白表达水平明显高于对照组细胞(0.921±0.091 vs 0.308±0.047,P<0.05)。实验组与对照组细胞相比,从第24 h实验组细胞生长速度减慢,细胞增值能力降低,两组比较差异有统计学意义(P<0.05);实验组细胞中Cyclin D1蛋白表达水平下降(0.436±0.023 vs 0.916±0.092,P<0.05),细胞周期的G₀/G₁期细胞比例升高［(85.1±5.2)% vs (63.8±3.1)%,P<0.05)］;S期细胞比例降低［(8.3±1.1)% vs(23.1±1.5)%,P<0.05］;实验组细胞Annexin Ⅴ增多,细胞早期凋亡率升高［(10.3±1.1)% vs (2.8±0.3)%,P<0.05］,抗凋亡蛋白Bcl-2表达水平降低(0.167±0.009 vs 0.834±0.084,P<0.05)。结论：BTG1高表达能明显抑制喉癌Hep-2细胞的生长增殖、诱导凋亡,其可能的机制与BTG1参与细胞周期调控、诱导细胞凋亡相关。     

新生霉素对人肝癌细胞的抑制作用

 目的　研究新生霉素 (NOVO)对人肝癌细胞的抗癌及其对临床常用抗癌药的调节作用。方法　采用抗癌药敏感试验 (MTT法 ) ,测定NOVO和 5种临床常用抗癌药单独应用对手术切除的原发性肝癌病人的肝癌细胞的抑制作用 ,同时测定NOVO和此 5种抗癌药联合应用的抑制作用。结果　NOVO对人肝癌细胞有抗癌作用 ,与 5种抗癌药联合应用对肝癌细胞的抑制率在低、中、高浓度均高于 5种抗癌药单独应用 ,差异均有显著性 ,P <0 .0 5。结论　结果表明NOVO对人肝癌细胞有较强的抗癌作用 ,并对诸如MMC、5 FU、DDP、CTX、ADM等有加强作用 ;NOVO可能有较大的临床应用价值     

PUMA mediates the combinational therapy of 5-FU and NVP-BEZ235 in colon cancer

Colon cancer is the third most common cancer in humans which has a high mortality rate, and 5-Fluorouracil (5-FU) is one of the most widely used drugs in colon cancer therapy. However, acquired chemoresistance is becoming the major challenges for patients, and the molecular mechanism underlying the development of 5-FU resistance is still poorly understood. In this study, a newly designed therapy in combination with 5-FU and NVP-BEZ235 in colon cancer cells (HCT-116 and RKO) was established, to investigate the mechanism of 5-FU resistance and optimize drug therapy to improve outcome for patients. Our results show 5-FU induced cell apoptosis through p53/PUMA pathway, with aberrant Akt activation, which may well explain the mechanism of 5-FU resistance. NVP-BEZ235 effectively up-regulated PUMA expression, mainly through inactivation of PI3K/Akt and activation of FOXO3a, leading to cell apoptosis even in the p53^−/− HCT-116 cells. Combination treatment of 5-FU and NVP-BEZ235 further increased cell apoptosis in a PUMA/Bax dependent manner. Moreover, significantly enhanced anti-tumor effects were observed in combination treatment in vivo. Together, these results demonstrated that the combination treatment of 5-FU and NVP-BEZ235 caused PUMA-dependent tumor suppression both in vitro and in vivo, which may promise a more effective strategy for colon cancer therapy.