雷帕霉素介导丝裂原活化蛋白激酶信号通路对肝癌细胞的影响

目的:探讨雷帕霉素介导丝裂原活化蛋白激酶(MAPK)信号通路对肝癌细胞Bcl-2、Bcl-xl及Bax蛋白表达的影响。方法:将人肝癌细胞BEL-7402细胞分为对照组和雷帕霉素处理组(20、50、100 ng/mL),观察各组BEL-7402细胞的形态变化、细胞增殖抑制率、凋亡及蛋白(MAPK、Bcl-2、Bcl-xl及Bax)表达。结果:随着雷帕霉素浓度的升高,BEL-7402细胞呈现崩解和坏死;对照组BEL-7402细胞增殖抑制率最低,雷帕霉素干预组BEL-7402细胞增殖抑制率高于对照组,随着时间及雷帕霉素浓度的升高,细胞生长抑制率逐渐升高;雷帕霉素处理组与对照组相比差异有统计学意义;随着浓度的升高,BEL-7402细胞凋亡率升高;对照组BEL-7402细胞中MAPK阳性表达率高于雷帕霉素处理组,雷帕霉素处理组随着浓度升高,MAPK阳性表达率不断降低;对照组BEL-7402细胞中Bcl-2、Bcl-xl蛋白升高,与雷帕霉素处理组比较存在显著差异,雷帕霉素处理组Bcl-2、Bcl-xl蛋白水平随着雷帕霉素的浓度升高而降低,Bax表达水平随着雷帕霉素的浓度升高而增加。结论:雷帕霉素能够抑制肝癌细胞增殖,加快坏死及破裂,随着雷帕霉素的浓度升高,凋亡程度增大,其作用机制可能与抑制MAPK、Bcl-2、Bcl-xl表达,促进Bax水平升高有关。

TIGAR基因真核表达载体的构建及在HepG_2细胞中的作用初探

目的:构建TP53诱导的糖酵解和凋亡调控子(TIGAR)全长cDNA的真核表达载体pEGFP-TIGAR,观察TIGAR在人肝细胞HepG2中的作用。方法:RT-PCR技术扩增获得TIGAR全长cDNA,将扩增的产物克隆,经酶切、DNA测序鉴定正确,构成pEGFP-TIGAR的真核表达重组质粒。利用脂质体将重组质粒转染入HepG2细胞,流式细胞仪和TUNEL法检测细胞凋亡、流式细胞仪检测细胞周期、MIB-1(Ki-67抗原测定)法检测细胞增殖、实时荧光PCR检测mRNA表达和Western-blot检测蛋白质的表达。结果:构建完成的真核表达重组质粒pEGFP-TIGAR,经DNA测序与GenBank中的人TIGARcDNA序列一致。荧光显微镜观察到转染重组质粒的细胞中有绿色荧光蛋白的表达。检测结果显示,转染pEGFP-TIGAR质粒的HepG2晚期凋亡细胞明显减少(P<0.05);S期细胞百分数则明显增加(P<0.05),增殖能力明显增高(P<0.05)。结论:本实验成功构建了pEGFP-TIGAR真核表达质粒,过表达的TIGAR可降低HepG2细胞发生晚期凋亡和促进细胞增殖,为进一步研究TIGAR基因在肿瘤细胞中作用提供了基础。

波形蛋白真核表达质粒载体的构建及其在HepG2细胞中的表达

目的构建重组人波形蛋白中间丝真核表达质粒载体pcDNA3.1-VIM并检测波形蛋白在肝癌HepG2细胞中的稳定表达。方法通过RT-PCR技术从人胎盘组织总RNA中扩增波形蛋白基因,经限制性核酸内切酶BamHⅠ-EcoRⅠ消化,然后插入pcDNA3.1(+)载体,脂质体介导重组质粒和空质粒分别转染HepG2细胞,G418筛选稳定表达细胞株,采用免疫细胞化学技术检测目的基因的表达。结果经DNA序列分析和限制性核酸内切酶消化,证实重组载体pcDNA3.1-VIM已正确克隆,建立的稳定细胞株高表达波形蛋白。结论成功地构建了重组质粒pcDNA3.1-VIM载体和建立了稳定表达波形蛋白的人肝细胞癌细胞株,为进一步研究波形蛋白与癌细胞生物学行为之间的相互关系奠定了基础。

耐索拉非尼的人肝癌BEL-7402细胞株的建立及其特征

目的:建立耐索拉非尼人肝癌BEL-7402的细胞株并研究其相关特征。方法:用CCK-8法检测药物对细胞增殖的抑制作用,Coulter计数法分析细胞倍增时间,流式细胞仪检测细胞周期以及活性氧自由基的水平,免疫印迹法检测蛋白的表达。结果:通过浓度递增的方法,诱导人肝癌BEL-7402细胞出现耐药性,得到了低倍耐药的细胞株。结果发现耐药细胞的增殖速度明显减慢,细胞周期发生改变,G1期细胞明显增多。使用相同浓度的索拉非尼处理细胞,与敏感细胞相比较,耐药细胞的活性氧自由基水平明显减少,凋亡相关蛋白P53表达降低,凋亡标志蛋白PARP-1的切割程度变轻。粉防己碱能逆转其耐药性。结论:成功建立了耐索拉非尼的人肝癌BEL-7402细胞株,为索拉非尼的耐药机制及相关药物研究奠定了良好的基础。

Casticin-induced apoptosis involves death receptor 5 upregulation in hepatocellular carcinoma cells

AIM:To investigate the apoptotic activities of casticin in hepatocellular carcinoma(HCC) cells and its molecular mechanisms.METHODS:PLC/PRF/5 and Hep G2 cell lines were cultured in vitro and the inhibitory effect of casticin on the growth of cells was detected by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolim bromide(MTT) assay.The apoptotic cell death was examined using the cell apoptosis enzyme linked immunosorbent assay(ELISA) detection kit,flow cytometry(FCM) after propidium iodide(PI) staining and DNA agarose gel electrophoresis.The caspase activities were measured using ELISA.Reactive oxygen species(ROS) production was evaluated by FCM after dichlorodihydrofluorescein diacetate(DCFH-DA) probe labeling.Intracellular glutathione(GSH) content was measured using a glutathione assay kit.The expression of death receptor(DR)4 and DR5 proteins was analyzed by Western blotting and FCM.RESULTS:Casticin significantly inhibited the growth of human HCC(PLC/PRF/5 and Hep G2) cells in a dosedependent manner(P < 0.05).Casticin increased the percentage of the sub-G1 population in HCC cells in a concentration-dependent manner.The potency of casticin to PLC/PRF/5 cells was higher than that of 5-flurouracil(26.8% ± 4.8% vs 17.4% ± 5.1%) at 10 μmol/L for 24 h.Casticin increased the levels of Histone/DNA fragmentation and the levels of active caspase-3,-8 and-9 in a concentration-dependent manner(P < 0.05).Treatment with 30 μmol/L casticin for 24 h resulted in the formation of a DNA ladder.Casticin reduced the GSH content(P < 0.05),but did not affect the level of intracellular ROS in PLC/PRF/5 and Hep G2 cells.The thiol antioxidants,acetylcysteine(NAC) and GSH restored GSH content and attenuated casticin-induced apoptosis.In contrast,the nonthiol antioxidants,butylated hydroxyanisole and mannitol failed to do so.In the HCC cells treated with casticin for 24 h,DR5 protein level was increased.The expression of DR5 protein induced by casticin was inhibited by NAC.Pretreatment with DR5/Fc chimera protein,a blocking antibody,effectively attenuated the induction of apoptosis by casticin.CONCLUSION:Casticin-induced apoptosis of HCC cells is involved in GSH depletion and DR5 upregulation.

Effects of cisplatin on telomerase activity and telomere length in BEL-7404 human hepatoma cells

Telomerase activity was inhibited in a dose and time-dependent manner with the treatment of cisplatin for 24, 48, or 72 h in a concentration ranged from 0.8 to 50 1uM in BEL-7404 human hepatoma cells. There were no changes in expression pattern of three telomerase subunits, its catalytic reverse transcriptase subunit (hTERT), its RNA component (hTR) or the associated protein subunit (TP1), after cisplatin treated for 72 h with indicated concentrations. Mean telomere lengths were decreased by the cisplatin treatment. Cell growth inhibition and cell cycle accumulation in G2/M phase were found to be correlated with telomerase inhibition in the present study, but percentages of cell apoptosis did not change markedly during the process.

Optimization of the microwave-assisted extraction of phlorotannins from Saccharina japonica Aresch and evaluation of the inhibitory effects of phlorotannin-containing extracts on HepG2 cancer cells

The use of a microwave-assisted extraction （MAE） method for the extraction ofphlorotannins from Saccharinajaponica Aresch （S.japonica） has been evaluated with particular emphasis on the influential parameters, including the ethanol concentration, solid/liquid ratio, extraction time, extraction temperature, and microwave power. The MAE procedure was optimized using single-factor design and orthogonal array design （OAD）. The content of total phlorotannins in S. japonica was determined using a Folin-Ciocalteu （FC） assay. A maximum total phlorotannin content of 0.644 mg of phloroglucinol equivalent per gram of dry weight plant （mg PGE/g DW） was obtained using the optimized model, which included an ethanol concentration of 55%, solid/liquid ratio of 1：8, extraction time of 25 min, irradiation power of 400 W, and temperature of 60~C. Under similar conditions, the application of a conventional extraction method led to a lower phlorotarmin yield of 0.585 mg PGE/g WD. These results demonstrated that the MAE approach provided better results for the extraction ofphlorotarmins from S.japonica and was a promising technique for the extraction of phenolic compounds from S. japonica and other materials. In addition, screening tests for the inhibitory activity showed that the phlorotannin-containing extracts significantly inhibited the growth of human hepatocellular carcinoma cells （HepG2） by inducing their apoptosis. The morphological changes that occurred during cell apoptosis were characterized using Hoechst33258 staining.

GABA stimulates human hepatocellular carcinoma growth through overexpressed GABAA receptor theta subunit

AIM: To investigate the function of gamma-aminobutyric acid (GABA) and gamma-aminobutyric acid A receptor θ subunit (GABRQ) in hepatocellular carcinoma (HCC). METHODS: Semiquantitative polymerase chain reaction was used for detecting the expression of GABRQ receptor among HCC cell line HepG2, normal liver cell line L-02, non-malignant Chang's liver cells, 8 samples of HCC tissues and paired non-cancerous tissues. HepG2 cells were treated with GABA at serial concentrations (0, 1, 10, 20, 40 and 60 μmol/L), and their proliferating abilities were analyzed with the methyl thiazolyl tetrazolium assay, cell cycle analysis and tumor implanted in nude mice. Small interfering RNA was used for knocking down the endogenous GABRQ in HepG2. Proliferating abilities of these cells treated with or without GABA were analyzed. RESULTS: We identified the overexpression of GABRQ in HCC cell lines and half of the tested HCC tissues. Knockdown of endogenous GABRQ expression in HepG2 attenuated HCC cell growth, suggesting its role in HCC cell viability. We studied the effect of GABA in the proliferation of GABRQ-positive cell lines in vitro and in vivo , and found that GABA increased HCC growth in a dosedependent manner. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRQ-expressing HepG2 cells, but not GABRQ-knockdown HepG2 cells, which means that GABA stimulates HepG2 cell growth through GABRQ. CONCLUSION: GABRQ play important roles in HCC development and progression and could be a promising molecular target for the development of new diagnostic and therapeutic strategies of HCC.

Fascaplysin sensitizes cells to TRAIL-induced apoptosis through upregulating DR5 expression

This study investigated the molecular mechanism of anti-tumor effect of fascaplysin, a nitrogenous red pigment firstly isolated from a marine sponge. Microarray analysis show that the TNF and TNF receptor superfamily in human umbilical vein endothelial cells (HUVEC) and human hepatocarcinoma cells (BEL-7402) were significantly regulated by fascaplysin. Western Blot results reveal that fascaplysin increased the expression of cleaved caspase-9, active caspase-3, and decreased the level of procaspase-8 and Bid. Flow cytometry and cytotoxicity tests indicate that fascaplysin sensitized cells to tumor necrosis-related apoptosis-inducing ligand-(TRAIL) induced apoptosis, which was markedly blocked by TRAIL R2/Fc chimera, a dominant negative form of TRAIL receptor DR5. Therefore, our results demonstrate that fascaplysin promotes apoptosis through the activation of TRAIL signaling pathway by upregulating DR5 expression.

rAdinbitor, a novel disintegrin from Agkistrodon halys brevicaudus stejneger inhibits adhesion and proliferation of SMMC-7721 cells

Objective： To investigate the effects of rAdinbitor on the adhesion and proliferation of human hepatoma cell strain 8MMC-7721. Methods： Cell adhesion assay was used to observe the effect of rAdinbitor on the adhesion of 8MMC-7721 cells to fibronectin （FN）. Crystal violet staining was performed to detect the influence of rAdinbitor on the adhesion of 8MMC- 7721 cells. MTT assay was employed to detect the inhibitory effects of different concentration of rAdinbitor on the proliferation of 8MMC-7721 cells. The morphologic changes of the control 8MMC-7721 cells and the apoptotic cells induced by 200μg/mL rAdinbitor for 36 h were observed under light microscope after HE staining. Flow cytometry analysis was applied to determine the apoptosis rate of 8MMC-7721 cells. Results： （1） FN promoted the adhesion of human hepatoma cell strain 8MMC-7721 in a dose-dependent manner. （2） rAdinbitor could dose-dependently inhibit the adhesion of SMMC-7721 cells to FN. The higher the concentration was, the stronger the inhibition was. There was significant difference among the groups （P 〈 0.05）. （3） rAdinbitor had a strong inhibition on the proliferation of 8MMC-7721 cells and showed a dose-dependent manner （P 〈 0.05）. After a 48 h exposure, the IC50 value of rAdinbitor was 177.83 μg/mL. （4） After exposure of 8MMC-7721 cells to 200μg/mL rAdinbitor for 36 h, the early morphologic changes appeared and the apoptosis rate was 20.68%, significantly higher than that of the control group （2.38%, P 〈 0.05）. Conclusion： rAdinbitor can dose-dependently inhibit the 8MMC-7721 cells adhesion to FN, and can inhibit the proliferation in dose-dependent manner and promote their apoptosis.

Anticancer Peptide from Chinese Toad （Bufo Bufo Gargarizans） Skin Enhanced Sensitivity to 5-Fu in Hepatocarcinoma cells （HepG2）

OBJECTIVE To investigate the antiproliferative and apoptogenic activities of peptide extracted from the Chinese toad （Bufo bufo gargarizans） skin （TSP） and its effects on hepatocarcinoma cell line. METHODS M1-F assay was used to detect the effects of TSP （50 lig/mL and 5 ug/mL） on the proliferation and viability of Hepatocarcinoma cell line （HepG2） and liver cell line （L-02）; Flow cytometry was used in DNA content analysis to determine the cell distribution in different phases of cell cycle; Annexin V-FITC/PI stained fluorescence-activated cell sorter （FACS） and transmission electron microscope （TEM） were used to detect the apoptosis of the treated cells. RESULTS TSP could not suppress the proliferation and viability of normal liver L-02 cells, but strongly inhibited the proliferation and viability of HepG2 cells; TSP （50 μg/mL） primarily arrested the HepG2 cells at G1 phase of the cell cycle; TSP （50μg/mL） induced apoptosis in HepG2 cells and enhanced the effects of 5-Fu. CONCLUSION TSP has potent antineoplastic activity against human hepatocarcinoma cells with little toxicity to normal liver cells and can enhance the effects of 5-Fu.

Secretory Transactivating Transcription-apoptin fusion protein induces apoptosis in hepatocellular carcinoma HepG2 cells

AIM:To determine whether SP-TAT-apoptin induces apoptosis and also maintains its tumor cell specificity. METHODS:In this study,we designed a secretory protein by adding a secretory signal peptide(SP) to the N terminus of Transactivating Transcription(TAT)-apoptin(SP-TAT-apoptin),to test the hypothesis that it gains an additive bystander effect as an anti-cancer therapy. We used an artificial human secretory SP whose amino acid sequence and corresponding cDNA sequence were generated by the SP hidden Markov model. RESULTS:In human liver carcinoma HepG2 cells,SP-TAT-apoptin expression showed a diffuse pattern in the early phase after transfection. After 48 h,however,it translocated into the nuclear compartment and caused massive apoptotic cell death,as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay and annexin-V binding assay. SP-TAT-apoptin did not,however,cause any cell death in non-malignant human umbilical vein endothelial cells(HUVECs). Most importantly,the conditioned medium from Chinese hamster ovary(CHO) cells transfected with SP-TAT-apoptin also induced significant cell deathin HepG2 cells,but not in HUVECs. CONCLUSION:The data demonstrated that SP-TAT-apoptin induces apoptosis only in malignant cells,and its secretory property might greatly increase its potency once it is delivered in vivo for cancer therapy.

Anti-proliferative activity of phlorotannin extracts from brown algae Laminaria japonica Aresch

In this study, we evaluated the anti-proliferative activity of phlorotannins derived from brown algae Laminariajaponica Aresch extracts on the human hepatocellular carcinoma cell （BEL-7402） and on routine leukemic cells （P388） by MTT assay. Cells were incubated with 100 μg/mL of the phlorotannin extract （PE） for 48 h. The inhibitory rate of PE on BEL-7402 and P388 cells was 30.20±1.16% and 43.44±1.86%, respectively, and the half-inhibitory concentration of PE （IC50） on P388 and BEL-7402 cells was 120 μg/mL and 〉200 μg/mL, respectively. Microscopic observation shows that the morphologic features of tumor cells treated with PE and 5-fluorouracil are markedly different from the normal control group. The inhibitory rate of fraction A2 isolated from PE by sephadex LH-20 for BEL-7402 and P388 cells at the sample concentration of 70.42 μg/mL was 61.96±7.02% and 40.47±8.70%, respectively. The apoptosis peak for fraction A2 was the most profound of all fractions used in the flow cytometry assay. The results indicate that the anti-proliferative of this algal extract is associated with the total phlorotannin content.

Effects of monoclonal antibodies against human stathmin 1 combined paclitaxel on proliferation of human hepatocellular carcinoma cell lines

Objective： We investigated the effects of monoclonal antibodies against stathmin 1 combined paclitaxel on the proliferation of HCC cells. Methods： HepG2 cells were treated with monoclonal antibodies against stathmin 1, paclitaxel alone or their combination, with the untreated cells used as the control, 24, 48, 72, 96 h later, the cell growth condition was observed by invert microscope and inhabitation rate was studied by MTT assay; The apoptosis was analyzed by flow cytometry with Annexin V/PI. Results： The population decreased and shape, size changed after treating with different concentration of experimental groups. Monoclonal antibodies against stathmin 1 and paclitaxel used alone or in combination both inhibited the proliferation of HepG2 cells, the inhibition ratio of their combination was more higher （P 〈 0.05）, and a synergistic effect of the two agents was noted in their combined action （P 〈 0.05）. Combined treatment of the cells resulted in significantly higher apoptosis rate than that in the other groups （P 〈 0.05）. Conclusion： Monoclonal antibodies against stathmin 1 and paclitaxel used alone or in combination both can inhibit proliferation of HepG2 cells and induce apoptosis. A synergistic effect is obsewed between the monoclonal antibodies against stathmin 1 and paclitaxel in their inhibition of HepG2 cell proliferation.

Aberrant methylation and downregulation of sall3 in human hepatocellular carcinoma

AIM: To investigated whether sall3 transcription was regulated by promoter CpG island hypermethylation in hepatocellular carcinoma (HCC). METHODS: The cell lines Huh7, HepG2, SK-HEP1, SM-MC7721, Bel7402, QGY7703 and a cohort of 38 HCC tissue specimens and corresponding nontumorous tissues were subjected to analysis for sall3 promoter CpG island methylation and mRNA transcription. sall3 promoter CpG island methylation levels were determined using the MassARRAY platform and mRNA transcription levels of the gene were detected by quantitative realtime polymerase chain reaction.RESULTS: The levels of sall3 mRNA were decreased by more than twofold in 33 of 38 tumor tissues compared to adjacent noncancerous tissues. Among these 33 tumor tissues with lower levels of sall3 mRNA, 24 showed higher levels of methylation. Based on these results, we hypothesized that the decrease in sall3 mRNA transcription level was likely due to promoter CpG island hypermethylation. Changes in sall3 mRNA transcription and promoter CpG island methylation were determined in the above six cell lines after treatment with 0, 0.1, 0.5 and 2.5 mmol 5-aza-2-deoxycytidine, a demethylating agent. Promoter CpG island methylation levels de- creased in a dose-dependent manner in all six cell lines, while the mRNA transcription level increased dose-dependently in Huh7, HepG2, SK-HEP1 and SMMC7721 cells and irregularly in Bel7402 and QGY7703 cells. CONCLUSION: These results indicated that promoter CpG island hypermethylation contributes to the downregulation of sall3 mRNA transcription in HCC.

EGF receptor-mediated intracellular calcium increasein human hepatoma BEL-7404 cells

Epidermal growth factor （EGF） induced intracellular free calcium ([Ca2+]i) response was studied in fura-2- or fluo-3-loaded human hepatoma cells of BEL-7404 cell line. Single cell [Ca2+]i analysis and [Ca2+], measurement in cell populations revealed that EGF triggered a rapid [Ca2+]iincrease in the dose-dependent and time- dependent manner. Pretreatment of cells with an endoplasmic reticulum （ER） Ca2+-ATPase inhibitor, thapsigargin （TG） at 100 nM concentration for 20 min, completely abolished EGF-induced [Ca2+]i increase, and chelating extracellular calcium by excess EGTA partially inhibited the increase.Furthermore, the expression of antisense EGF receptor sequence in BEL-7404 cells suppressed the [Ca2+]i response to EGF. The results suggest that EGF receptor-mediated [Ca2+]i increase in the human hepatoma cells is essentially dependent on the Ca2+ storage in ER.

Antisense EGFR sequence enhances apoptosis in a human hepatoma cell line BEL-7404

Effects of antisense epidermal growth factor receptor (EGFR) sequence on apoptotic cell death were examined in a human hepatoma cell line BEL-7404 cells. In the cells of JX-1, a sub clone of BEL-7404 stably transfected with antisense EGFR vector (Cell Research, 3:75, 1993), an enhanced rate (9.5%) of spontaneous apoptosis was detected by flow cytometry, whereas the rates of spontaneous apoptosis in JX-0 cells, a sub-clone of BEL-7404 transfected by control vector, and the parellt BEL-7404 cells were almost equal and about 1.7%. Serum-starvation for 72 h increased the rate of apoptosis of JX-1cells up to 33.7%, while JX-0 and BEL-7404 cells, under the same condition, produced less than 5% of apoptotic cells. Observation with electron microscope demonstrated that condensation and fragmentation of chromatin and formation of apoptotic bodies of ten occurred in JX-1 cells, especially during serumstarvation. These results, combined with the data of DNA fragmentation Elisa test, suggested that antisense EGFR sequence enhances apoptosis in the human hepatoma cells.Comparison of intracellular Ca2+ level and the responsiveness of JX-1 cells to the induced action of EGF and tharpsigargin (TG) treatment with that of control JX-0cells indicated that antisense EGFR might interrupt the EGF/EGFR signaling pathway resulting in the decreass of intracellular Ca2+ pool content as well as the responsiveness of these cells to the extracellular signals. These findings suggest that antisense EGFR either directly or indirectly reglllates Ca2+ storage in endoplasmic reticulum,thereby enhances apoptosis in the hnman hepatoma cells.

Growth-inhibitory effects of MOB2 on human hepatic carcinoma cell line SMMC-7721

AIM:To investigate the growth-inhibiting and apoptosis-inducing effects of the gene MOB2 on human hepatic carcinoma cell line SMMC-7721.METHODS:The full-length cDNA of the MOB2 gene was amplified from human umbilical vein endothelial cells.The correct full-length MOB2 cDNA was subcloned into the eukaryotic expression vector pEGFP-C1.After lipofection of the MOB2 gene into cancer cells,the levels of MOB2 protein in the cancer cells were detected by immunoblotting.To transfect the recombined plasmid vector pEGFP-CI-MOB2 into SMMC-7721 cells,the cells were cultured in Dulbecco's Modified Eagle'sMedium with 10% fetal calf serum and glutamine,and then mixed with liposomes,Lipofectamine 2000 and the plasmid vector pEGFP-CI-MOB2.RESULTS:We observed the growth and proliferation of SMMC-7721 cells containing pEGFP-CI-MOB2 and analyzed their apoptosis and growth cycle phases by flow cytometry.We successfully transfected the recombined plasmid vector pEGFP-CI-MOB2 into SMMC-7721 cells and screened for a single clone cell containing MOB2.After transfection,MOB2 enhanced growth suppression,induced apoptosis,increased the ratio of G0/G1,significantly inhibited the advance of cell cycle phase,and arrested cells in G0/G1 phase.CONCLUSION:MOB2 overexpression induces apoptosis and inhibits the growth of human hepatic cancer cells,which may be useful in gene therapy for hepatic carcinoma.

The Impact Heme Oxygenase -1 on the Regulating Factors of Hepatoma Cells＇ Cell Cycle

It aims to analyze the impact heme oxygenase -1 （heme oxygenase 1, HO-1） on regulating factors of human hepatoma cell HepG2＇s cell cycle, through constructing recombinant vector of pcDNA3.1 containing wild-type and mutant HO-1 gene （＋）-wtHO-1 and pcDNA3.1 （＋）-mHO-1G143H. By using the method of liposome-mediated, the recombinant vector was transfected hepatoma cell line HepG2. And the transfected one with empty vector was treated as a control group. By the selection of G418, stable expression of wild-type and mutant HO-1 in HepG2 liver cancer cell lines were established. Use the blot of semi-quantitative RT-PCR and Western to test transfected cell lines expressing levels of riO-1 mRNA and protein. As HO-1 expression in stably transfected cell lines altered, we use Western blot to test transfected cell lines P21, P27 protein expression levels. As result shows, we got 1 HO-over-expression of wild-type and mutant in HepG2 cells; wild- type and mutant＇s over expression of HO-1 can induce the expression of tumor suppressor genes p21 and p27.we got the conclusion that HO-l＇s over-expression of tumor suppressor genes p21 and p27 is unrelated to the expression of heme decomposition products. HO-1 may regulate the expression of p21 and p27 through other mechanisms.

Celastrus orbiculatus extract induces mitochondrial-mediated apoptosis in human hepatocellular carcinoma cells

OBJECTIVE： To investigate the apoptotic effects and underlying molecular mechanisms of Celastrus orbiculatus （C. orbiculatus） extract in human hepa- tocellular carcinoma cells. METHODS： Human hepatocellular carcinoma cells （HCCLM6） were treated with C. orbiculatus extract （COE） at different nontoxic concentrations （10, 20, 40, 80, and 160 IJg/mL）. The effect of COE on HC-CLM6 viability was examined using 3-（4,5-dimethyl- thiazol-2-yl）-2,5-diphenyl tetrazolium bromide （MTT） assays. Cellular apoptosis following COE treatment was assessed by flow cytometry and western blot analysis. RESULTS： COE significantly inhibited cell viability and induced apoptosis of HCCLM6 cells in a dose-dependent manner. Apoptosis was accompa- nied by increased Bax expression and decreased Bcl-2 expression. In addition, COE treatment led to the release of cytochrome c, activation of cas- pase-3, and cleavage of poly （ADP-ribose） poly- merase （PARP）. Furthermore, activation of extracel- lular signal-regulated kinase （ERK）, p38 kinase, and c-Jun N-terminal kinase （JNK） phosphorylation, and down-regulation of Akt phosphorylation was ob- served. CONCLUSION： COE induces mitochondrial-mediat- ed, caspase-dependent apoptosis in HCCLM6 cells, which might be attributed to the activation of mito- gen-activated protein kinase （MAPK） and inhibition of Akt signaling pathways. These data suggest that COE may be a potential treatment for human hepa- tocellular carcinoma.