吲哚美辛诱导肝癌细胞凋亡及与环氧合酶-2和凋亡调控基因表达关系

目的探讨非甾体类抗炎药(MSAIDs)诱导肝癌细胞株SMMC7721细胞凋亡的作用及可能机制,为其应用于肝细胞癌的化学预防和治疗提供实验和理论依据.方法采用TUNEL法和免疫细胞化学方法研究了不同浓度吲哚美辛对肝癌细胞株SMMC7712的诱导凋亡作用,及其对环氧合酶(COX)-2和凋亡相关基因p53、p27kipl、C-myc蛋白和Fas抗原表达的影响.结果①对照组、100、200、400、600和800μmol/L吲哚美辛组肝癌细胞的细胞凋亡指数分别为(2.4±1.4)%、(4.2±1.5)%、(8.0±3.2)%、(14.3±5.1)%、(14.9±4.3)%和(19.0±6.1)%(P＜0.0001).②对照组、100、200、400、600和800μmol/L吲哚美辛组COX-2的表达强度分别为强阳性、强阳性、强阳性、阳性、弱阳性和弱阳性.③对照组、100、200、400、600和800μmol/L吲哚美辛组p27kipl的阳性积分分别为0,3.7±1.4,12.3±2.4,26.3±4.5,44.4±5.1和60.6±7.8(P＜0.0001);p53阳性积分分别为5.3±1.2,6.1±2.3,24.1±6.1,46.2±6.9,47.3±6.6和49.0±5.1(P＜0.0001);C-myc的阳性积分分别为5.8±1.6,5.9±1.7,18.6±6.3,22.0±5.6,44.0±8.4,和44.3±6.1(P＜0.0001);Fas阳性积分分别为21.7±6.0,24.2±5.5,25.7±5.9,24.3±5.4,23.1±6.6和22.3±4.3(P＞0.05).结论吲哚美辛可诱导肝癌细胞凋亡,且与其抑制COX-2表达和上调肝癌细胞内p53、p27kipl、C-myc蛋白表达有关.     

Inhibitory effect of interferon-α-2b on expression of cyclooxygenase-2 and vascular endothelial growth factor in human hepatocellular carcinoma inoculated in nude mice

AIM： To evaluate the effects of interferon-α-2b （IFN- α-2b） on expression of cyclooxygenase-2 （COX-2） and vascular endothelial growth factor （VEGF） in human hepatocellular carcinoma （HCC） inoculated in nude mice and to study the underlying mechanism of IFN-α- 2b against HCC growth. METHODS： Thirb/-two nude mice bearing human HCC were randomly divided into four groups （n = 8）. On the 10th day after implantation of HCC cells, the mice in test groups （groups A, B and C） received IFN-α- 2b at a serial dose （10000 IU for group A, 20000 IU for group B, 40000 IU for group C sc daily） for 35 d. The mice in control group received normal saline （NS）. The growth conditions of transplanted tumors were observed. Both genes and proteins of COX-2 and VEGF were detected by RT-PCR and Western blot. Apoptosis of tumor cells in nude mice was detected by TUNEL assay after treatment with IFN-α-2b. RESULTS： Tumors were significantly smaller and had a lower weight in the IFN-α-2b treatment groups than those in the control group （P 〈 0.01）, and the tumor growth inhibition rate in groups A, B and C was 27.78%, 65.22% and 49.64%, respectively. The expression levels of both genes and proteins of COX-2 and VEGF were much lower in the IFN-α-2b treatment groups than in the control group （P 〈 0.01）. The apoptosis index （AI） of tumor cells in the IFN-α-2b treatment groups was markedly higher than that in the control group （P 〈 0.01）. Group B had a higher inhibition rate of tumor growth, a lower expression level of COX-2 and VEGF and a higher AI than groups A and C （P 〈 0.05）, but there was no significant difference between groups A and C. CONCLUSION： The inhibitory effects of IFN-α-2b on implanted tumor growth and apoptosis may be associated with the down-regulation of COX-2 and VEGF expression. There is a dose-effect relationship. The medium dose of IFN-α-2b for inhibiting tumor growth is 20 000 IU/d.     

短发夹状RNA对人肝癌细胞环氧合酶-2的抑制作用

目的:构建针对人环氧合酶-2(COX-2)基因编码区的短发夹状RNA(shRNA)真核表达载体质粒,观察其在不同时间点对人不同肝癌细胞株COX-2表达的影响.方法:以人COX-2mRNA编码区作为RNA干扰靶点,构建shRNA真核表达载体质粒WBH1和WBH2,应用阳离子脂质体分别转染人肝癌细胞株HepG2和Bel7402,利用逆转录聚合酶链反应和Westernblot法分别观察两株细胞转染后24,48,72,和96hCOX-2mRNA和蛋白的表达变化,检测抑制效果.结果:质粒在HepG2细胞和Bel7402细胞中的转染率分别约为60%和54%.WBH1导入细胞24,48,72和96h后,逆转录聚合酶链反应检测COX-2mRNA表达抑制率,HepG2细胞分别为18.5%,88.6%,52.8%和42.4%(P<0.01).Bel7402细胞分别为9%,45.1%,70.1%和56.3%(P<0.01).Westernblot法检测蛋白表达抑制率,HepG2细胞分别为10.3%,80.5%,45.3%和39.0%(P<0.01);Bel7402细胞分别为8.3%,40.2%,66.4%和35.6%(P<0.01).质粒WBH2对COX-2的表达无影响(P>0.05).结论:针对人COX-2的shRNA能高效特异的抑制不同肝癌细胞株的COX-2表达.HepG2细胞和Bel7402细胞分别以48h和72h抑制效果最明显.56.3%(P<0.01).Westernblot法检测蛋白表达抑制率,HepG2细胞分别为10.3%,80.5%,45.3%和39.0%(P<0.01);Bel7402细胞分别为8.3%,40.2%,66.4%和35.6%(P<0.01).质粒WBH2对COX-2的表达无影响(P>0.05).结论:针对人COX-2的shRNA能高效特异的抑制不同肝癌细胞株的COX-2表达.HepG2细胞和Bel7402细胞分别以48h和72h抑制效果最明显.     

Ubiquitin-conjugating enzyme E2T knockdown suppresses hepatocellular tumorigenesis via inducing cell cycle arrest and apoptosis

BACKGROUND Hepatocellular carcinoma(HCC) is now the most common primary liver malignancy worldwide, and multiple risk factors attribute to the occurrence and development of HCC. Recently, increasing studies suggest that ubiquitinconjugating enzyme E2 T(UBE2 T) serves as a promising prognostic factor in human cancers, although the molecular mechanism of UBE2 T in HCC remains unclear.AIM To investigate the clinical relevance and role of UBE2 T in HCC development.METHODS UBE2 T expression in HCC tissues from the TCGA database and its association with patient survival were analyzed. A lentivirus-mediated strategy was used toknock down UBE2 T in HCC cells. q RT-PCR and Western blot assays were performed to check the effect of UBE2 T silencing in HCC cells. Cell growth in vitro and in vivo was analyzed by multiparametric high-content screening and the xenograft tumorigenicity assay, respectively. Cell cycle distribution and apoptosis were determined by flow cytometry. The genes regulated by UBE2 T were profiled by microarray assay.RESULTS UBE2 T was overexpressed in HCC tissues compared with paired and non-paired normal tissues. High expression of UBE2 T predicted a poor overall survival in HCC patients. In vitro, lentivirus-mediated UBE2 T knockdown significantly reduced the viability of both SMMC-7721 and BEL-7404 cells. In vivo, the xenograft tumorigenesis of SMMC-7721 cells was largely attenuated by UBE2 T silencing. The cell cycle was arrested at G1/S phase in SMMC-7721 and BEL-7404 cells with UBE2 T knockdown. Furthermore, apoptosis was increased by UBE2 T knockdown. At the molecular level, numerous genes were dysregulated after UBE2 T silencing, including IL-1 B, FOSL1, PTGS2, and BMP6.CONCLUSION UBE2 T plays an important role in cell cycle progression, apoptosis, and HCC development.     

丹参酮ⅡA对肝癌SMMC-7721细胞COX-2表达的影响

目的:观察丹参酮ⅡA对肝癌SMMC-7721细胞生长和凋亡的影响及其作用机制．方法:体外培养肝癌SMMC-7721细胞株,经丹参酮ⅡA(终浓度0．5 mg／L)作用后,采用四唑盐(MTT)比色法检测细胞增殖,透射电镜观察细胞凋亡,流式细胞仪检测细胞凋亡,免疫细胞化学SABC法检测COX-2蛋白表达,放射免疫法检测前列腺素E2(PGE2)含量．结果:丹参酮ⅡA对肝癌细胞的生长有明显的抑制作用,并呈剂量依赖性．以0．5 mg／L作用终浓度抑制作用最明显,其48 h的抑制率为 69．3％,与对照组相比差异有显著性(P<0．01)．电镜下观察,丹参酮ⅡA作用后肝癌细胞表现为细胞皱缩、核染色质浓缩、核碎裂以及凋亡小体形成等凋亡特征性的形态改变．5 mg/ L丹参酮ⅡA作用后,随时间的延长,凋亡率逐渐升高,48 h达到高峰,随后逐渐下降(24,48, 72 h凋亡率分别为7．45％±0．33％、6．59％± 0．45％、4．78％±1．05％),与对照组比较,各处理组都有显著性差异(均P<0．01),丹参酮作用组肝癌细胞COX-2表达明显减少,其培养液中 PGE2的产生量下降,与对照组相比差异均有显著性(P<0．01)．结论:丹参酮ⅡA可能是通过下调COX-2 mRNA的表达水平发挥其对肝癌细胞生长抑制及促进凋亡作用．     

Induction of apoptotic cell death by direct-current treatment in human leukemic cell lines

Exposure of human leukemic cell lines (HL-60, ML-1, U-937, MOLT-4, EOL-1) to short direct-current (d.c.) treatment induced apoptotic cell death, characterized by cell shrinkage and nuclear and internucleosomal DNA fragmentation. On the other hand, human peripheral blood lymphocytes and polymorphonuclear cells were relatively resistant to d.c treatment, and did not show any clear nuclear and DNA fragmentation. The effect of d.c. was slightly reduced by calcium depletion, but was not significantly affected by catalase or by superoxide dismutase. The present data suggest that previously reported tumor regression activities of d.c. treatment might be due, at least in part, to its apoptosis-inducing activity.     

Cell cycle arrest and apoptotic cell death in cultured human gastric carcinoma cells mediated by arsenic trioxide

AIM: To investigate the effect of arsenic trioxide on human gastric cancer cell line MKN45 with respect to both cytotoxicity and induction of apoptosis in vitro. METHODS: MKN45 cells were treated with arsenic trioxide (As2O3) at the concentration of 1, 5, and 10 μmol/L, respectively, for three successive days. Cell growth and proliferation were observed by cell counting and trypan blue exclusion. Cytotoxicity of As2O3 was determined by MTT assay. Morphologic changes were studied with light microscopy. Flow cytometry was used to assay cell DNA distribution and apoptotic cells were confirmed with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and DNA electrophoresis. RESULTS: The growth of MKN45 cells was significantly inhibited by As2O3 which was confirmed by colony-forming assay. After 7 d of culture with various concentrations of As2O3, colony-forming capacity of MKN45 cells decreased with As2O3 increment in comparison with that of control group. The inhibitory rate of colony-formation was 38.5%, 99.1%, and 99.5% when the concentration of As2O3 was 1, 5, and 10 μmol/L in culture medium, respectively. The cell number of a single colony in drug treatment groups was less than that of control group. The cell-killing rate of As2O3 to MKN45 cells was both dose- and time-dependent with an IC50 of (11.05±0.25) μmol/L After incubation in 10 μmol/L As2O3 for 24 h, the cell-killing rate was 27.1%, and it was close to 50% after 48 h. The results showed that As2O3 induced time- and dose-dependent apoptosis in MKN45 cells, blocked at G2/M phase. The apoptotic peak (sub-G1 phase) appeared and cell apoptotic rate in MKN45 cells was 18.3-32.5% after treatment by 10 umol/L As2O3 for 48 h. The percentage of G2/M cell of the experimental groups was 2.0-5.0 times than that of the control group. Gel electrophoresis of DNA from cells treated with each concentration of As2O3 for 48 h revealed a "ladder" pattern, indicating preferential DNA degradation at the internucleosomal, linker DNA sections. TUNEL also demonstrated strand breaks in DNA of MKN45 cells treated with As2O3, while control cells showed negative labeling. CONCLUSION: As2O3 can induce apoptosis of human gastric carcinoma cells MKN45, which is the basis of its effectiveness. It shows great potential in the treatment of gastric carcinoma.     

舒林酸诱导人肝细胞癌凋亡及对环氧合酶-2和Bcl-2蛋白表达的影响

目的 探讨舒林酸在肝细胞癌化学预防和治疗中的应用价值。方法 采用人肝细胞癌细胞株SMMC7721，HepG2作为研究对象。体外药物敏感试验检测不同浓度和作用时间的舒林酸对细胞的增殖抑制效应；分别用Hoechst33258细胞核荧光染色和透射电镜观察舒林酸诱导的细胞凋亡的形态学改变，并计算相应的细胞凋亡指数（AI）；应用Western斑点印迹法观察不同浓度舒林酸作用后细胞内环氧合酶-2（COX-2）和凋亡抑制蛋白Bcl-2表达程度的变化。结果 舒林酸对人肝细胞癌细胞SMMC7721，HepG2具有显著的增殖抑制和凋亡诱作用，并且具有时间和剂量依赖性，舒林酸对不同类型细胞的杀伤率和凋亡诱导效应有显著差异。经舒林酸2mmol/L和4mmol/L作用24h后，细胞内COX-2和Bcl-2蛋白的表达比未经舒林酸作用的细胞表达明显减少。结论 舒林酸在体外对人肝细胞癌细胞株SMMC7721和HepG2具有显著的增殖抑制和诱导凋亡作用。且与其抑制细胞内COX-2和Bcl-2蛋白的表达有关。     

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-7721 hepatoma 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-diphenylte-trazolium (MTT) bromide colorimetric assay. Celecoxib-induced 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 MTT 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-7402 and 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-3 and 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.     

Ethanol induces apoptotic death of beta-endorphin neurons in the rat hypothalamus by a TGF-beta 1-dependent mechanism

Background:  We have previously shown that developing β-endorphin neurons, in the arcuate nucleus of the hypothalamus become increasingly apoptotic when exposed to ethanol. As in the previous study we have observed an involvement in transforming growth factor beta 1 (TGF-β1) in mediation of the apoptotic process, the present study was conducted to determine the ethanol-induced changes in this apoptotic regulatory peptide signaling in the arcuate nucleus of the hypothalamus of neonatal rats.
Methods:  Pups were exposed to 11.34% ethanol in a milk-based diet or control diet on postnatal day (PND) 3 to PND7. Two hours after the last daily feeding, brains were collected and frozen in liquid nitrogen for analysis of various apoptosis regulatory proteins in the arcuate tissue by Western blots. Some animals were fixed in 4% paraformaldehyde and analyzed immunohistochemically.
Results:  Ethanol exposure increased apoptotic death of β-endorphin neurons in the arcuate nucleus of the hypothalamus. The cell death was associated with an increase in the tissue levels of TGF-β1 in the mediobasal hypothalamus. This was correlated with a reduction in the arcuate level of retinoblastoma protein (Rb) phosphorylation. The reduced level of Rb phosphorylation was associated with an increased protein level of the cyclin dependent kinase inhibitor p27/kip but with a decreased protein level of cyclin dependent kinase 4 and cyclin D3. In addition, the apoptotic cell death was positively correlated with the level of Bclxs but negatively correlated with the level of the Bcl2.
Conclusions:  These results suggest that ethanol exposure increases TGF-β1 signaling involving Bcl2 and Rb repression that may lead to apoptotic death of cells including β-endorphin neurons in the arcuate nucleus of the hypothalamus.     

Selective COX-2 inhibitor, NS-398, suppresses cellular proliferation in human hepatocellular carcinoma cell lines via cell cycle arrest

AIM: To investigate the growth inhibitory mechanism of NS-398, a selective cyclooxygenase-2 (COX-2) inhibitor, in two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh7). METHODS: HepG2 and Huh7 cells were treated with NS-398. Its effects on cell viability, cell proliferation, cell cycles, and gene expression were respectively evaluated by water-soluble tetrazolium salt (WST-1) assay, 4’-6-diamidino-2-phenylindole (DAPI) staining, flow cytometer analysis, and Western blotting, with dimethyl sulfoxide (DMSO) as positive control. RESULTS: NS-398 showed dose- and time-dependent growth-inhibitory effects on the two cell lines. Proliferating cell nuclear antigen (PCNA) expressions in HepG2 and Huh7 cells, particularly in Huh7 cells were inhibited in a time- and dose-independent manner. NS-398 caused cell cycle arrest in the G1 phase with cell accumulation in the sub-G1 phase in HepG2 and Huh7 cell lines. No evidence of apoptosis was observed in two cell lines. CONCLUSION: NS-398 reduces cell proliferation by inducing cell cycle arrest in HepG2 and Huh7 cell lines, and COX-2 inhibitors may have potent chemoprevention effects on human hepatocellular carcinoma.     

Bile acids induce cyclooxygenase-2 expression via the epidermal growth factor receptor in a human cholangiocarcinoma cell line

BACKGROUND & AIMS: Although bile acids have been implicated in colon cancer development, their role in biliary tract carcinogenesis remains unexplored. Because receptor tyrosine kinases and cyclooxygenase (COX)-2 have been implicated in carcinogenesis, we examined the hypothesis that bile acids modulate these enzymes in KMBC cells, a human cholangiocarcinoma cell line. METHODS: The effect of bile acids on epidermal growth factor receptor (EGFR) stimulation, mitogen-activated protein kinase (MAPK) activation, and COX-2 expression was evaluated. RESULTS: Bile acids both induced EGFR phosphorylation and enhanced COX-2 protein expression. Bile acid-induced EGFR phosphorylation was associated with subsequent activation of MAPK p42/44, p38, and c-Jun-N-terminal kinase (JNK). The MAPK inhibitors, PD098059 for MAP or extracellular signal-regulated kinase 1, SB203580 for p38, and BAY 37-9751 for Raf-1, blocked COX-2 induction by bile acids. However, inhibition of JNK activity did not block bile acid-mediated COX-2 induction. CONCLUSIONS: The results show that EGFR is activated by bile acids and functions to induce COX-2 expression by an MAPK cascade. This induction of COX-2 may participate in the genesis and progression of cholangiocarcinomas.     

肺炎支原体LAMPs经PI3K/Nrf2诱导人单核细胞表达HO-1

目的 探讨肺炎支原体(Mycoplasma pneumoniae,Mp)脂质相关膜蛋白(lipid-associated membrane protein,LAMPs)对人单核细胞表达血红素氧合酶-1(heme oxygenase-1,HO-1)的影响,并探讨可能的调控机制。方法 体外培养THP-1细胞,用不同浓度的LAMPs作用后,分别采用realtime-PCR和Western blot检测HO-1 mRNA和蛋白的表达。同时采用不同浓度的放线菌素D(ActD)和放线菌酮(CHX)预处理细胞,观察其对HO-1表达的影响,以证实HO-1的表达是否通过转录和翻译水平;提取LAMPs作用前后的核蛋白,凝胶迁移率实验检测Nrf2的核转位、Western blot检测Akt的磷酸化情况;同时采用PI3K抑制剂LY294002处理细胞,观察其对LAMPs诱导Nrf2核转位及HO-1表达的影响;最后采用 siRNA干扰Nrf2表达,以证实Nrf2是否参与调控HO-1表达。结果 (1)0~5 μg/mL LAMPs能以剂量依赖性方式诱导THP-1表达HO-1 mRNA和蛋白;(2)5 μg/mL LAMPs能诱导THP-1细胞Akt磷酸化,并能增强其DNA结合活性;PI3K抑制剂LY294002处理后,可明显抑制LAMPs诱导的HO-1表达和Nrf2核转位;(3)干扰Nrf2表达后,可明显下调LAMPs诱导THP-1细胞表达HO-1。结论 LAMPs可诱导THP-1细胞表达HO-1,其机制可能与PI3K/Nrf2通路有关。     

Cytokine-induced apoptotic cell death in a mouse pancreatic beta-cell line: inhibition by Bcl-2

Summary Cytokines are thought to contribute to the induction of pancreatic beta-cell destruction in insulin-dependent diabetes mellitus. The molecular mechanisms that underlie beta-cell death were investigated by studying cytokine-induced cell death in beta-cell lines. A combination of three cytokines (interleukin-1, tumour necrosis factor-, and interferon-) induced apoptotic cell death in the mouse pancreatic beta-cell line TC1, as judged from the appearance of cells with hypodiploid nuclei and oligonucleosomal DNA fragmentation. The same treatment also induced apoptosis in the mouse pancreatic alpha-cell line TC1 and the NOD/Lt mouse beta-cell line NIT-1, although to a lesser extent than in TC1 cells. The abundance of endogenous Bcl-2 in TC1 cells was lower than that in the other two cell lines. Overexpression of human Bcl-2 in TC1 cells partially protected them from cytokine-induced cell death. These results suggest that apoptosis may be responsible, at least in part, for cytokine-induced beta-cell destruction and that Bcl-2 prevents apoptosis in pancreatic islet cells.Abbreviations IDDM Insulin-dependent diabetes mellitus - IL interleukin - TNF tumour necrosis factor - IFN interferon - FBS fetal bovine serum - ATA aurintricarboxylic acid - CHX cycloheximide - PI propidium iodide     

Bcl-2 expression and its association with cell kinetics in human gastric carcinomas and intestinal metaplasia

Thebcl-2 protooncogene was initially discovered at the t(14;18) chromosomal breakpoint in follicular lymphomas. It has been demonstrated thatbcl-2 protein (Bcl-2) expression blocks apoptosis and plays an important role in cell development and maturation. In the present study, Bcl-2 expression was immunohistochemically examined in 103 cases of gastric carcinoma, as well as 64 cases of non-carcinous gastric mucosa, and its correlation with apoptosis, cell proliferation and p53 immunoreactivity was investigated. Bcl-2 was detected in 18.0% of differentiatedtype gastric carcinomas (9 of 50) and 7.5% of the undifferentiated type (4 of 53). In adjacent intestinal metaplastic gastric epithelium, the incidence of Bcl-2 positivity in the incomplete type (21/23, 91.3%) was significantly higher than in the complete type (23/41, 56.1%) (P<0.04). Double immunostaining for Bcl-2 and Ki-67 clearly revealed the majority of Bcl-2-positive cancer cells to be in a nonproliferating state, although some cancer cells expressed both proteins together. Statistical assessment demonstrated that the average Ki-67 labeling index and apoptotic labeling index in Bcl-2-positive foci were significantly lower than in Bcl-2-negative foci (P<0.0001,P<0.0003). In addition, a significant dissociation between Bcl-2 and p53 immunoreactivity was found in cancer tissues. These results indicate that aberrant Bcl-2 expression in gastric carcinomas possibly originates from intestinal metaplastic epithelium, and suggest a possible role in tumor development and growth.Abbreviation IM intestinal metaplasia     

塞来昔布对肝癌HepG2细胞生长及KAI1/CD82蛋白表达的影响

目的:探讨塞来昔布对人肝癌HepG2细胞增殖、凋亡以及KAI1/CD82蛋白表达的影响.方法:用不同浓度的塞来昔布(12.5、25.0、50.0、100.0、200.0 μmol/L)干预人肝癌HepG2细胞24、48、72 h后.采用CCK-8法测定HepG2细胞体外增殖活性:利用流式细胞术检测细胞凋亡率:应用Wes...     

Expression of cyclooxygenase-2 (COX-2) in human esophageal cancer and in vitro inhibition by a specific COX-2 inhibitor, NS-398

BACKGROUND: The purpose of the present paper was to study the expression of cyclooxygenase-2 (COX-2) in normal squamous epithelium, squamous dysplasia and squamous cell carcinoma (SCC) of the esophagus, to elucidate the role of COX-2 in esophageal carcinogenesis, and to evaluate the in vitro effect and mechanism of a COX-2 inhibitor, NS-398, in inducing growth inhibition and apoptosis of human esophageal cancer cells. METHODS: Biopsy specimens of esophageal dysplasia (n = 21), and surgical resections of SCC (n = 37) were compared with normal esophagus (n = 37) and analyzed by RT-PCR. Human esophageal cells were used for the study. Anti-proliferative effect was measured by MTT, apoptosis was determined by DNA fragmentation assay. RESULTS: Marked COX-2 expression was shown in SCC and esophageal squamous dysplasia, and no marked COX-2 expression was observed in the normal squamous epithelium, respectively. NS-398 could inhibit esophageal cells growth in a dose-dependent manner, induce apoptosis, and elevate caspase-3 activity in vitro. CONCLUSIONS: This study provides evidence that COX-2 is upregulated in the majority of cases of squamous dysplasia and SCC of esophagus, and that NS-398 can inhibit growth and induce apoptosis via activating caspase-3 activity in vitro. These results suggest that selective inhibitors of COX-2 may be an effective preventive and therapeutic option for esophageal carcinoma.     

Melatonin prevents cell death and mitochondrial dysfunction via a SIRT1‐dependent mechanism during ischemic‐stroke in mice

Silent information regulator 1 (SIRT1), a type of histone deacetylase, is a highly effective therapeutic target for protection against ischemia reperfusion (IR) injury (IRI). Previous studies showed that melatonin preserves SIRT1 expression in neuronal cells of newborn rats after hypoxia–ischemia. However, the definite role of SIRT1 in the protective effect of melatonin against cerebral IRI in adult has not been explored. In this study, the brain of adult mice was subjected to IRI. Prior to this procedure, the mice were given intraperitoneal with or without the SIRT1 inhibitor, EX527. Melatonin conferred a cerebral‐protective effect, as shown by reduced infarct volume, lowered brain edema, and increased neurological scores. The melatonin‐induced upregulation of SIRT1 was also associated with an increase in the anti‐apoptotic factor, Bcl2, and a reduction in the pro‐apoptotic factor Bax. Moreover, melatonin resulted in a well‐preserved mitochondrial membrane potential, mitochondrial Complex I activity, and mitochondrial cytochrome c level while it reduced cytosolic cytochrome c level. However, the melatonin‐elevated mitochondrial function was reversed by EX527 treatment. In summary, our results demonstrate that melatonin treatment attenuates cerebral IRI by reducing IR‐induced mitochondrial dysfunction through the activation of SIRT1 signaling.