三联脆组基因对胰腺癌细胞增殖及凋亡的影响

目的：研究三联脆组基因(fragile histidine triad,FHIT)对胰腺癌细胞增殖的影响,探讨FHIT基因对胰腺癌增殖的抑癌机制。方法：通过脂质体介导的方法将pRC／CMV FHIT质粒转染有FHIT全基因丢失的胰腺癌1990细胞株。用RT－PCR及Western-blot方法对获得G418抗性细胞进行外源性FHIT基因整合及表达的鉴定。对导入有外源性FHIT基因表达的细胞（1990p FHIT)进行 细胞生长特征及裸鼠致瘤性分析。经光镜及电镜对1990pFHIT进行观察,并对其进行DNA片段化分析。结果：转染FHIT基因的1990细胞,有外源性FHIT基因的整合及表达,其增殖活性明显减弱,裸鼠致瘤性明显降低或消失。1990pFHIT细胞中存在明显的凋亡现象。结论：导放外源性的FHIT基因,通过某种途径诱导胰腺癌细胞的凋亡,从而抑制肿瘤细胞的恶性增殖。     

Bax、Bcl—2及FHIT在胰腺癌中的表达及意义

目的：研究胰腺癌组织及细胞中Bax／Bcl-2蛋白和FHIT mRNA的表达，探讨FHIT与凋亡相关因子在胰腺癌中的关系。方法：应用ABC免疫组织化学方法检测胰腺癌细胞和组织标本中Bax与Bcl-2蛋白，RT－PCR检测其中FHITmRNA的表达。结果：38例胰腺癌中Bax蛋白阳性17例（45％），Bcl-2蛋白阳性表达22例（58％），FHITmRNA异常表达为21例（56％），转染有外源性FHIT的1990细胞（1990pFHIT)Bax表达阳性率有升高，Bcl-2／Bax比值下降，结论：Bax、Bcl-2及FHIT都通过调控凋亡参与胰腺癌的病理过程，FHIT诱导凋亡可能与Bax上调表达有关。     

Effect of fragile histidine triad gene transduction on proliferation and apoptosis of human hepatocellular carcinoma cells

AIM： To evaluate the inhibitory effects of human fragile histidine triad （FHIT） gene on cell proliferation and apoptosis in human hepatocellular carcinoma line Hep3B in vitro.
METHODS： A recombinant pcDNA3.1 （＋）/FHIT including the functional region of FHIT gene was constructed and transferred into human hepatocellular carcinoma cells in vitro, mRNA and protein expression of the FHIT gene in the transfected cells was detected by RT-PCR and Western blot, respectively. The effect of FHIT on proliferation was detected by MTT assay. Changes in cell cycle and apoptosis were assayed by flow cytometry. Five mice received subcutaneous transplantation of Hep3B-FHIT; 5 mice received subcutaneous transplantation of normal Hep3B and Hep3B-C as controls. The body weight of nude mice and tumor growth were measured.
RESULTS： RT-PCR and Western blot analysis showed that the expression level of FHIT-mRNA and FHIT protein was higher in Hep3B cells after infection with pcDNA3.1 （＋）/FHIT. The growth of Hep3B cells treated with pcDNA3.1 （＋）/FHIT was significantly inhibited. The pcDNA3.1 （＋）/FHIT-transfected Hep3B cells showed a significantly higher cell rate at G0-G1 phase and increased apoptosis in comparison with controls （P 〈 0.05）. The growth of transplanted tumor was inhibited markedly by FHIT. Tumors arising from the Hep3B-FHIT cells occurred much later than those arising from the Hep3B and Hep3B-C cells. The growth of Hep3B-FHIT cells was slow and the tumor volume was low.
CONCLUSION： Transduction of FHIT gene inhibits the growth of human hepatocellular carcinoma cells and induces cell apoptosis in vivo and in vitro.     

DPC4基因对人胰腺癌细胞JF305增殖的影响

目的研究肿瘤抑制基因DPC4(deleted in pancreatic carcinoma)对人胰腺癌细胞系JF305增殖能力的影响。方法将携带DPC4基因的真核表达载体转入JF305细胞内,经G418筛选获得DPC4稳定表达细胞株,免疫细胞化学和RT-PCR法检测转染前后细胞内DPC4的表达。用MTT法、细胞计数法和流式细胞仪测定细胞生长曲线、细胞周期、细胞贴壁率和细胞克隆形成率。比较转染前后细胞增殖能力的变化。结果未转染及转染空质粒的JF305细胞无DPC4的表达,转染pBK-CMV-DPC4的JF305细胞可检测到DPC4的表达,且其细胞增殖能力较前明显下降(P<0．001),细胞倍增时间显著延长(由11．8d延长至18d),细胞贴壁率和克隆形成率均明显下降(P<0．0001),G_1期细胞所占比例明显增加(P<0．0001),G_2／M期细胞所占比例明显下降(P<0．0001)。结论无DPC4表达的胰腺癌细胞株JF305可转基因获得DPC4稳定表达,DPC4转基因后可抑制其增殖能力,细胞G_1期延长,G_2／M期缩短。DPC4有望成为胰腺癌基因治疗新的候选基因。     

TFPI-2基因体外诱导胰腺癌Panc-1细胞的凋亡

目的: 将TFPI-2基因转染胰腺癌细胞系Panc-1细胞, 研究其对胰腺癌细胞凋亡的影响.方法:将重组质粒pEGFP-C1-TFPI-2通过脂质体介导转染胰腺癌细胞系Panc-1细胞, G418筛选获得阳性细胞克隆后, 用逆转录-聚合酶链反应(RT-PCR)和免疫印迹(Western blot)技术分别检测转染细胞中TFPI-2 mRNA及相应蛋白的表达, 同时测定转染细胞的生长曲线和凋亡情况. 结果: 同转染空载体及未转染细胞相比, 转染成功的Panc-1细胞可以检测到TFPI-2 mRNA和相应蛋白的表达, 细胞生长受到抑制(n = 9, P = 0.02), DNA琼脂糖凝胶电泳显示凋亡细胞特有的"梯状"条带.结论:外源性TFPI-2基因能够抑制胰腺癌细胞生长增殖、诱导胰腺癌细胞凋亡.     

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。     

生长抑素2型受体基因转染对胰腺癌细胞蛋白表达的影响

目的 探讨生长抑素2型受体(hSSTR2)基因转染对胰腺癌细胞PANC1蛋白表达的影响,以寻找新的胰腺癌敏感治疗靶点.方法 利用前期构建的腺病毒载体Ad.CMV.hSSTR2.GFP将hSSTR2全长cDNA导入胰腺癌细胞PANC1.采用双向荧光差异凝胶电泳(2D-DIGE)技术分离并筛选转染hSSTR2的实验组、空载体对照组以及空白组胰腺癌细胞之间差异表达蛋白,用反射式基质辅助激光解吸附电离串联飞行时间质谱(MALDI-TOF/TOF)技术对差异蛋白进行鉴定.结果 hSSTB2成功地转染了胰腺癌细胞,获得了hSSTR2阴性和阳性表达的PANC1荧光差异蛋白表达图谱,经DeCyder v6.5软件分析,共有18个差异在1.3倍以上的蛋白质点,经质谱鉴定得到13个蛋白质.低表达的蛋白7个,为GMP合酶、磷酸化应激诱导蛋白、谷氨酸脱氢酶、Septin-11、波形蛋白、异柠檬酸脱氢酶α亚基、线粒体内膜易位酶;高表达蛋白6个,为真核延长因子1α1、丙酮酸激酶异构体M2型、烯酰-CoA水合酶、转录调节因子1-β、Mitofilin、HSP105.结论 hSSTR2基因转染胰腺癌细胞PANC1后引起蛋白表达发生变化,这些差异蛋白功能涉及到糖、脂肪、核酸代谢以及细胞生长调节和细胞凋亡等,从而为寻找新的胰腺癌敏感治疗靶点奠定基础.     

染色体缺失磷酸酶及张力蛋白同源物对胰腺癌细胞系细胞周期和增殖能力的影响

目的探讨10号染色体缺失的磷酸酶及张力蛋白同源物(PTEN)对胰腺癌细胞质(ASPC-1)血管内皮生长因子(VEGF)蛋白表达、细胞周期和增殖的影响.方法将质粒pEAK8-PTEN和pEAK8分别转染指数生长期的胰腺癌细胞株(ASPC-1),挑选阳性细胞克隆,扩增培养,用RT-PCR、Western印迹、流式细胞术、生长速率等方法分别检测PTEN对ASPC-1细胞VEGF蛋白、细胞周期及增殖能力的影响.结果ASPC-1细胞转染后,PTEN mRNA表达量是转染前的3倍;ASPC-1、ASPC-1-pEAK8、ASPC-1-pEAK8-PTEN细胞PTEN蛋白表达量分别为13.2、12.6和21.6,VEGF蛋白表达量分别为17.2、16.5和13.1,转染后较转染前降低.细胞周期显示,ASPC-1-pEAK8-PTEN细胞较ASPC-1、ASPC-1-pEAK8细胞G2/M、S期细胞增多,Gl期细胞减少,并出现少量凋亡细胞(P＜0.01).ASPC-1-pEAK8-PTEN细胞生长曲线平缓,生长速度较另两种细胞明显降低.结论 PTEN可使ASPC-1细胞VEGF蛋白表达下降,细胞阻滞在G2/M期,抑制肿瘤细胞增殖.     

外源性p16基因对人肺癌细胞生物学特性的影响

目的：研究外原性p16基因对肺癌细胞生物学特性的影响。方法：利用脂质体介导的基因转染方法将外源性p16基因转入p16基因缺陷的人肺腺癌细胞株A549中,用逆转录聚合酶链反应（RT－PCR）及免疫组化的方法检测p16基因的表达,同时观察转染后细胞恶性生长的变化。结果：外源性p16基因在A549细胞中能稳定表达,转染后A549细胞生长速度明显减慢,在软琼脂上形成克隆的能力降低。流式细胞仪检测显示A549细胞G1期阻滞并发生了凋亡,接种裸鼠后致瘤性降低,肿瘤生长明显减慢。结论：外源性p16基因导入人肺癌细胞株A549中可稳定表达并抑制细胞的恶性生长,同时诱导调亡。     

MSX2 overexpression inhibits gemcitabine-induced caspase-3 activity in pancreatic cancer cells

AIM: To evaluate the effect of MSX2 on gemcitabine-induced caspase-3 activation in pancreatic cancer cell line Panc-1. METHODS: Using V5-tagged MSX2 expression vector, stable transfectant of MSX2 was generated from Panc-1 cells (P×l4 cells). Cell viability under gemcitabine administration was determined by MTT assay relative to control cell line (empty-vector transfected Panc-1 cells; P-3EV cells). Hoechst staining was used for the detection of apoptotic cell. Activation of caspase-3 was assessed using Western blotting analysis and direct measurement of caspase-3 specific activities. RESULTS: MSX2 overexpression in Panc-1 cells resulted in decreased gemcitabine-induced caspase-3 activation and increased cell viability under gemcitabine treatment in P×l4 cells. CONCLUSION: MSX2 exerts repressive effects on gemcitabine-induced apoptotic pathway. This novel apoptosis-regulating function of MSX2 may provide a new therapeutic target for pancreatic cancer.     

吉西他滨对Beclinl基因沉默的人胰腺癌MiaPaCa-2细胞的周期及凋亡的影响

目的 探讨吉西他滨对Beclinl基因沉默的人胰腺癌MiaPaCa-2细胞周期及凋亡的影响.方法 构建靶向Beclinl的siRNA,插入表达质粒,转染MiaPaCa-2细胞.采用RT-PCR法和蛋白质印迹法检测细胞Beclinl mRNA及蛋白的表达,应用吉西他滨处理Beclinl基因沉默的MiaPaCa-2细胞,应用流式细胞仪检测细胞周期及细胞凋亡状况.结果 成功获得Beclin1基因沉默的MiaPaCa-2细胞,转染后细胞的Beclin1 mRNA表达量从对照组的1.0下降到0.295;S、G2期细胞数减少,而G1期细胞增多;细胞凋亡未受影响.应用吉西他滨处理后,Beclin1基因沉默的MiaPaCa-2细胞的S期细胞数进一步减少,而G1、G2期细胞增多,细胞凋亡被抑制.结论 Beclinl表达沉默使人胰腺癌细胞系MiaPaCa-2细胞周期发生改变,并影响吉西他滨对细胞周期及凋亡的作用.     

The <Emphasis Type="Italic">PMAIP1</Emphasis> Gene on Chromosome 18 is a Candidate Tumor Suppressor Gene in Human Pancreatic Cancer

Frequent loss of heterozygosity on the long arm of chromosome 18 is observed in pancreatic cancer. Previous studies suggested the existence of one or more tumor-suppressor genes other than SMAD4 on chromosome 18. To identify the candidate tumor-suppressor gene(s), we compared gene expression by cDNA microarray analyses using a pancreatic cancer cell line Panc-1 and its hybrid cell lines showing suppressed cell growth after introduction of one normal copy of chromosome 18. The microarray analyses identified 38 genes on chromosome 18 that showed differential expressional levels. Among these genes, phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1/APR/NOXA) was identified as one of the candidates for tumor suppressor. Expression vector-mediated introduction of PMAIP1 suppressed cell proliferation, and RNAi-mediated knockdown of PMAIP1 induced recovery of cell growth. These results suggest that PMAIP1 may play an important role in the progression of pancreatic cancer.     

Heme oxygenase-1 accelerates tumor angiogenesis of human pancreatic cancer

Angiogenesis is necessary for the continued growth of solid tumors, invasion and metastasis. Several studies clearly showed that heme oxygenase-1 (HO-1) plays an important role in angiogenesis. In this study, we used the vital microscope system, transparent skinfold model, lung colonization model and transduced pancreatic cancer cell line (Panc-1)/human heme oxygenase-1 (hHO-1) cells, to precisely analyze, for the first time, the effect of hHO-1 gene on tumor growth, angiogenesis and metastasis. Our results revealed that HO-1 stimulates angiogenesis of pancreatic carcinoma in severe combined immune deficient mice. Overexpression of human hHO-1 after its retroviral transfer into Panc-1 cells did not interfere with tumor growth in vitro. While in vivo the development of tumors was accelerated upon transfection with hHO-1. On the other hand, inhibition of heme oxygenase (HO) activity by stannous mesoporphyrin was able transiently to delay tumor growth in a dose dependent manner. Tumor angiogenesis was markedly increased in Panc-1/hHO-1 compared to mock transfected and wild type. Lectin staining and Ki-67 proliferation index confirmed these results. In addition hHO-1 stimulated in vitro tumor angiogenesis and increased endothelial cell survival. In a lung colonization model, overexpression of hHO-1 increased the occurrence of metastasis, while inhibition of HO activity by stannous mesoporphyrin completely inhibited the occurrence of metastasis. In conclusion, overexpression of HO-1 genes potentiates pancreatic cancer aggressiveness, by increasing tumor growth, angiogenesis and metastasis and that the inhibition of the HO system may be of useful benefit for the future treatment of the disease.     

Expression of the death gene Bik/Nbk promotes sensitivity to drug-induced apoptosis in corticosteroid-resistant T-cell lymphoma and prevents tumor growth in severe combined immunodeficient mice.

Members of the Bcl-2 gene family have been implicated in the regulation of cell death induced by cytostatic drugs. In some malignancies such as B-cell lymphoma, there is evidence that high expression of Bcl-2 is an independent negative prognostic marker and the overexpression of Bcl-2 has been shown to confer resistance to cytotoxic drugs by preventing drug-induced apoptosis. This function of Bcl-2 can be antagonized by apoptosis-promoting members of the Bcl-2 family. We previously showed that overexpression of Bax restores the chemosensitivity of Bax-deficient breast cancer cell lines. Therefore, we investigated whether the death-promoting Bcl-2 homologue Bik/Nbk can enhance cytostatic drug-induced apoptosis. As a model, we used the T-cell leukemia H9 (CD3(+) and CD4(+)CD8(-)), which is resistant to corticosteroid-induced cell death and does not express endogenous Bik/Nbk. Sensitivity for drug-induced apoptosis was increased 10- to 39-fold in cells transfected with the full-length coding sequence of Bik/Nbk. In addition, apoptosis induced via CD95/Fas or heat shock was increased to a similar extent. These data show that Bik/Nbk, which, unlike Bax, carries only a BH3 but no BH1 or BH2 domain may be a target to enhance chemosensitivity. The complete suppression of tumor growth in a severe combined immunodeficient mouse xenotransplant model suggests that, in analogy to Bax, Bik/Nbk may function as a tumor suppressor gene.     

KAI1 is a potential target for anti-metastasis in pancreatic cancer cells

AIM： To investigate whether KAI1, as a metastasis suppressor gene, is associated with invasive and metastatic ability of pancreatic cancer cells.METHODS： KAI1 gene was transfected into pancreatic cancer cell line MiaPaCa Ⅱ by liposomes selected with G418. Expression of transfected cells was measured by Western blotting, immunofluorescence and immunocytochemistry. Tumor cell invasion and metastatic ability were detected through gelatinase activity and reconstituted basement membrane （Matrigel） assay. pCMV-KAI1 was directly injected into the heterotopic human pancreatic adenocarcinoma successfully established in the groin of BALB/C nude mice, by subcutaneous injection of MiaPaCa Ⅱ pancreatic cancer cells. The statistical analysis between groups was determined by Student＇s two tailed t test.RESULTS： By Western blotting, MiaPaCa Ⅱ cells transfected by KAI1 gene indicated KAI1 expression at approximately 29.1 kDa. Cytoplasm staining was positive and uniformly spread in transfected cancer cells, using immunohistochemistry and immunofluorescence. The most obvious difference was present after 30 h （MiaPaca Ⅱ 43.6 ± 9.42, pCMV-MiaPaca Ⅱ 44.8 ± 8.56, pCMV-KAI1-MiaPaca Ⅱ 22.0 ± 4.69, P 〈 0.05）. Gelatinolysis revealed a wider and clearer band of gelatinolytic activity in non-transfected than in transfected cells （MiaPaCa Ⅱ cells 30.8 ± 0.57, transfected cells 28.1 ± 0.65, P 〈 0.05）. In vivo tumor growth rates of KAI1 transfectants with KAI1-Lipofectamine 1.22 ± 0.31 in A group were lower than control 4.61 ± 1.98 and pCMV-KAI 11.67 ± 0.81. Analyses of metastases with and without KAI1 transfection in mice were different in liver and lung between controls 1.62 ± 0.39, 0.45 ± 0.09, pCMV-KAI 1.01 ± 0.27, 0.33 ± 0.09 and KAI1-Lipofectamine 0.99 ± 0.21, 0.30 ± 0.09 respectively （P 〈 0.05）.CONCLUSION： High expression of KAI1 gene was found in transfected MiaPaCa Ⅱ human pancreatic cancer cells with lower metastatic ability. KAI1 gene plays an important role in inhibiting     

长链非编码RNA HOTAIR对胰腺癌细胞增殖、迁移能力的影响

目的探讨长链非编码RNA(long non-coding RNA,lncRNA)HOTAIR在胰腺癌细胞系(AsPC-1和Panc-1)中的表达,分析其对细胞增殖、迁移生物学能力的影响。方法体外培养人胰腺癌细胞系(Panc-1、AsPC-1),利用qRT-PCR技术检测lncRNA HOTAIR在胰腺癌细胞中的表达水平,并通过基因转染上调或下调HOTAIR的表达,观察HOTAIR对胰腺癌细胞增殖、迁移能力的影响。结果 HOTAIR过表达对AsPC-1细胞增殖能力影响较弱,但可促进Panc-1细胞增殖;HOTAIR过表达对两种细胞迁移均有促进作用。HOTAIR敲低抑制两种胰腺癌细胞增殖,并抑制两种胰腺癌细胞的迁移能力。结论 HOTAIR可增强胰腺癌细胞增殖、迁移的能力,提示HOTAIR可能与胰腺癌的进展和预后相关。     

PIAS1基因沉默对雨蛙肽诱导胰腺腺泡细胞凋亡的影响

活化STAT蛋白抑制物(PIAS)1基因沉默可增强雨蛙肽诱导的胰腺腺泡细胞炎症反应。目的:探讨PIAS1基因沉默对雨蛙肽刺激胰腺腺泡细胞凋亡的影响。方法:AR42J胰腺腺泡细胞在Lipofectamine~(TM)2000介导下转染PIAS1-siRNA和阴性siRNA。将细胞分为PIAS1-siRNA+雨蛙肽组、阴性siRNA+雨蛙肽组、脂质体+雨蛙肽组、PBS+雨蛙肽组和对照组。以DNA Ladder、Hoechst 33258染色检测细胞凋亡情况,流式细胞术测定细胞周期和细胞凋亡率,RT-PCR和蛋白质印迹法检测1353、Bax、Bcl-2、caspase-3 mRNA和蛋白表达。结果:与其余各组相比,PIAS1-siRNA+雨蛙肽组DNA梯度裂解条带明显增加,荧光着色阳性细胞数增多;G1期细胞数增多,S期细胞数减少,细胞凋亡率增加;p53、Bax、caspase-3 mRNA和蛋白表达明显上调,Bcl-2 mRNA和蛋白表达下调(P均0.05)。结论:PIAS1基因沉默可增强雨蛙肽活化的caspase-3凋亡途径诱导的胰腺腺泡细胞凋亡,为通过调控PIAS1表达治疗急性胰腺炎提供新的理论依据。     

吲哚美辛与埃罗替尼对胰腺癌细胞生长的协同抑制作用

背景：目前胰腺癌药物化疗疗效不佳。既往研究提示环氧合酶（COX）-2和表皮生长因子受体（EGFR）信号途径均参与了胰腺癌的发生、发展，COX-2抑制剂和EGFR抑制剂联用对胰腺癌的生长可能具有协同抑制作用。目的：观察COX-2抑制剂吲哚美辛与EGFR酪氨酸激酶抑制剂埃罗替尼对胰腺癌细胞生长的协同抑制作用。方法：以甲基噻唑基四唑（MTT）比色法检测胰腺癌细胞株BxPC-3的增殖情况，以流式细胞分析和原位末端标记（TUNEL）法观察用药前后细胞凋亡和细胞周期的变化，以逆转录聚合酶链反应（RT—PCR）观察用药前后细胞中COX-2、EGFR以及凋亡相关基因Bcl-2、Bax、Bcl-xL、Bak mRNA表达的变化。结果：BxPC-3细胞中可观察到COX-2和EGFRmRNA表达．吲哚美辛和埃罗替尼单用均可下调COX-2和EGFRmRNA的表达，两者联用时下调作用更明显。吲哚美辛和埃罗替尼单用均可抑制BxPC-3细胞增殖，促进细胞凋亡，诱导细胞周期阻滞于G0／G1期，减少抗凋亡基因Bcl-2、Bcl-xL的表达，轻微上调促凋亡基因Bax的表达，两者联用对细胞生长的抑制作用增强。结论：吲哚美辛和埃罗替尼均可抑制COX-2和EGFR的表达，下调Bcl-2／Bax比值，两者联用对胰腺癌细胞生长具有协同抑制作用。