Ginsenoside Rh_2 Showing Ability to Induce Apoptosis in HeLa Cells

This paper deals with the inhibitory mechanisms of ginsenoside \{G Rh 2\} on the growth of tumor cells. \{G Rh 2\} significantly inhibited the proliferation of human cervical adenocarcinoma HeLa cells in a time and dose dependent manner. G Rh 2 induced apoptotic manifestations in HeLa cells as evidenced by the changes in the cell morphology, the DNA fragmentation and the activation of caspases. Caspase inhibitors, caspase family inhibitor, z Val Ala Asp fmk(z VAD fmk); caspase 1 inhibitor, Ac Tyr Val Ala Asp chloromethyl ketone(Ac YVAD cmk); caspase 3 inhibitor, z Asp Glu Val Asp fmk(z DEVE fmk) and caspase 8 inhibitor, \{z Ile \}Glu Asp fmk(z IETD fmk) effectively attenuated G Rh 2 induced cell death. The activities of caspase 1 and caspase 3 were increased in the G Rh 2 induced apoptotic process. However, caspase inhibitors can not inhibit G Rh - 2 induced cell death completely. These results suggest that G Rh 2 induced cell death is mediated by the activation of caspase cascade, but there might be some other pathways for induction of this apoptosis.

Arsenic Trioxide Inhibits Proliferation in K562 Cells by Changing Cell Cycle and Survivin Expression

To study the mechanisms involved in the inhibition of chronic myeloid leukemic cells (K562) proliferation induced by arsenic trioxide (As 2O 3) and to explore the potential role of Survivin, an inhibitor of apoptosis protein, in the regulation of As 2O 3 induced cell apoptosis, K562 cells were cultured with As 2O 3 of different concentrations. Cells were collected for proliferation analysis by MTT assay. Cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Expression of Survivin protein and mRNA were detected by flow cytometry and RT-PCR, respectively. Our results showed that As 2O 3 (2-10 μmol/L) inhibited K562 cells growth effectively, but it did not induce cells apoptosis significantly. The percentage of K562 cells at G 2/M phase increased in proportion to As 2O 3 concentrations, and the expression of Survivin mRNA and content of Survivin protein was up-regulated accordingly. It is concluded that As 2O 3 inhibited K562 cells growth by inducing cell cycle arrest mainly at G 2/M phase. Over-expression of Survivin gene and protein might be one of the possible mechanisms contributing to K562 cells' resistance to As 2O 3-induced apoptosis.

Cucurbitacin E inhibits the proliferation of hepatoma cells in vitro and in vivo through induction of G2/M phase arrest

Objective Cucurbitacins are the highly oxygenated tetracyclic triterpenes,which are predominantly found in the Cucurbitaceae family but are also present in several other families of the plant kingdom.A number of compounds of this group have been investigated for their cytotoxic,hepatoprotective,anti-inflammatory,cardiovascular and anti-diabetic activities.In China,the cucurbitacin preparation,which contains mostly cucurbitacin B and cucurbitacin E,has been clinically used for the treatment of the primary liver carcinoma.It has been previously reported that cucurbitacin E could produce cytotoxicity against a variety of cancer cells,and various mechanisms were implicated in its cytotoxic effect.The present study is to investigate the effect of cucurbitacin E on hepatoma cells in vitro and in vivo and to study their potential mechanisms of action.Methods The MTT assay was used to assess the viability of human HepG2 and BEL7402 hepatoma cells in vitro after treatment with different concentrations of cucurbitacin E.The cell cycle distribution was determined by flowcytometric analysis after propidium iodide(PI)staining.The cell cycle-related proteins were detected using western blotting analysis.Implanted mouse hepatoma H22 model was built to evaluate the growth inhibitory effect of cucurbitacin E in vivo in mice.Results Our studies found that cucurbitacin E(10-300 nM)produced anti-proliferative effect on human HepG2 and BEL7402 hepatoma cells in vitro without cytotoxicity.According to flowcytometric analysis,cucurbitacin E arrested the cell cycle at G2/M phase in both HepG2 and BEL7402 hepatoma cells after 24 h treatment.Cucurbitacin E induced the decrease in the level of CDK1 protein and the increase in the level of p21 protein,but had no effect on the levels of cyclin A,cyclin B1 and Cdc25C protein.In in vivo anti-tumor experiment,cucurbitacin E had significant inhibitory effects on the growth of mouse H22 hepatoma cells.Conclusions Cucurbitacin E inhibited the proliferation of hepatoma cells in vitro and in vivo,at least in part,through induction of cell cycle arrest at G2/M phase,which was mediated by concomitant upregulation of p21 and downregulation of CDK1.We consider that cucurbitacin E may be useful in the treatment of liver cancer.

Genistein-induced Anticancer Effects on Acute Leukemia Cells Involve the Regulation of Wnt Signaling Pathway Through H4K20mel Rather Than DNA Demethylation

Objective:To investigate the effects and mechanisms of genistein on the gene expression in the Wnt pathway in acute leukemia(AL)cells.Methods:The expression of Wnt pathway genes and cell cycle-related genes were analyzed in two AL cell lines.Pyrophosphate sequencing was performed to determine the methylation degree.Then,the enrichment of H4K20mel and H3K9ac was determined using ChIP-qPCR.Flow cytometry was used to analyze the cell cycle.Results:The IC_(50) of genistein in the two AL cell lines was lower than that for the bone marrow mesenchymal stem cell line.Genistein upregulated H4K20mel,KMT5A and Wnt suppressor genes,including Wnt5a,and downregulated the downstream target genes of Wnt,such as c-myc and β-catenin.The methylation degree and H3K9ac enrichment in the Wnt5a promoter region remained unchanged.However,the enrichment of H4K20mel in the Wnt5a promoter and coding regions increased.In addition,genistein upregulated Phospho-cdc2,Mytl,Cyclin A,Cyclin E2,p21 and Phospho-histone H3,but downregulated Phospho-weel.Cell cycle arrest was induced in the G2/M phase.Conclusion:Genistein inhibits the activation of the Wnt pathway by promoting the expression of Wnt5a through the activation of KMT5A and enrichment of H4K20mel in the Wnt5a gene promoter and coding regions,rather than demethylation.Genistein also blocks the cell cycle in the G2/M phase.Therefore,genistein is a potential anti-leukemia drug.

Greater Expansion of IFN-<i>γ</i>^﹣CD4⁺NKT Cells in HIV-1 Compared with HIV-2-Infected Subjects with Preserved CD4⁺T Cell Counts

Context: Human Natural Killer T cells are T lymphocytes that express an invariant αβ T cells receptors and NK cells receptors. They regulate innate and adaptive immune response but are susceptible to HIV-1 infection. Objective: We compare the frequency and the activity of NKT cells in HIV-1 and HIV-2 infected individuals with CD4+ counts greater than 500/mm3 using flow cytometry after overnight stimulation with phytohemagglutinin (PHA). Results: The frequency of NKT cells was similar between both groups and also to sero-negative control subjects. There were also no significant differences in the proportions of total NKT cells and the CD4+ NKT subset that secreted interferon gamma (IFN-γ) after polyclonal stimulation. However, there was a significantly higher frequency of IFN-γ﹣ CD4+ NKT cells in HIV-1-infected compared with HIV-2 infected subjects (p = 0.043). Conclusion: These data suggest there is no relationship between the functional activity of NKT cell subsets and the total NKT cell population in HIV infection. The expansion of IFN-γ﹣ CD4+ NKT cells in HIV-1 infection may serve as target for viral infection and may eventually result in their depletion during chronic infection.

三氧化二砷对HBx-Hep G_2细胞侵袭转移能力的影响

目的探讨三氧化二砷(As_2_3)对HBx—Hep G_2细胞体外黏附、侵袭、迁移能力的影响及其机制。方法慢病毒介导构建HBx—Hep G_2细胞模型,免疫细胞化学法检测HBx蛋白表达,分别采用MTT法、Transwell小室检测As_2O_3对HBx—Hep G_2细胞黏附、迁移、侵袭能力的影响,免疫组化方法检测As_2O_3作用前后HBx-Hep G_2细胞CD44V6表达的改变。结果构建后的HBx—Hep G_2细胞呈现HBx阳性信号,主要分布于胞浆,无局部高浓度聚集。随着As_2O_3作用时间的延长及浓度增加,HBx—Hep G_2细胞对Matrigel的黏附能力也随之增加;与作用前相比,As_2O_3作用后HBx—Hep G_2细胞游走与穿透基底膜的能力明显受抑制[(128±8)vs.(102±7)、(96±5)vs.(85±6)]个/HP(P<0.05);与As_2O_3作用前比较,H-SCOKE及阴性表达率均下降[(3.75±0.55)vs.(2.54±0.68)、(92.65±4.86)%vs.(63.27±5.98)%]能抑制HBx—Hep G_2细胞CD44v6的表达(P<0.05)。结论 As_2O_3能抑制HBx-Hep G_2细胞与细胞的黏附、迁移和侵袭能力,其抑制作用可能与CD44v6的表达下调有关。

基于G蛋白信号调节因子2敲低探讨血管紧张素Ⅱ诱导的主动脉夹层形成的机制

目的探讨G蛋白信号调节因子2(RGS2)在调节血管紧张素Ⅱ(AngⅡ)诱导的主动脉夹层形成中的作用。方法将C57BL/6小鼠分为3组:Control组(n=10)、AngⅡ组(n=20)、AngⅡ+sh-RGS2组(n=20)。AngⅡ组和AngⅡ+sh-RGS2组小鼠建立了主动脉夹层模型。在体内评估主动脉夹层的发生率,在体外和体内评估血管平滑肌细胞(VSMC)表型转化。结果RGS2的敲低逆转了AngⅡ导致的αSMA、ACTA2和MYH11的表达下调,并抑制了AngⅡ诱导的SPP1和Vimentin蛋白表达。AngⅡ组和AngⅡ+sh-RGS2组的主动脉夹层发生率分别为45%(9/20)和10%(2/20)。与AngⅡ组小鼠比较,AngⅡ+sh-RGS2组小鼠中观察到更少的弹性层增厚、主动脉破裂和主动脉壁胶原纤维含量。此外,与AngⅡ组比较,AngⅡ+sh-RGS2组主动脉的最大直径减小(P<0.05),ACTA2、MYH11蛋白增加(P<0.01),RGS2、SPP1、Vimentin蛋白降低(P<0.01)。结论RGS2敲低抑制AngⅡ诱导的VSMC从可收缩表型转变为合成表型,降低了主动脉夹层形成的发生率。

肝星状细胞特异性Grk2基因敲除小鼠模型的制备及鉴定

目的利用Cre-loxP基因敲除技术建立肝星状细胞特异性G蛋白偶联受体激酶2(G protein-coupled receptor kinase 2,GRK2)基因敲除小鼠模型,为研究GRK2在肝星状细胞中的生物学功能提供动物模型基础。方法将loxP标记的Grk2基因小鼠(Grk2^(fl/fl))和Lrat-Cre工具鼠进行多次繁殖,建立肝星状细胞特异性Grk2基因敲除(Grk2^(ΔHSC))小鼠模型。观察和分析小鼠的生长繁殖情况;通过PCR反应鉴定flox和Cre基因型;免疫荧光双染检测肝星状细胞中GRK2表达;Western blot检测小鼠肝星状细胞及肺、脾、肾脏、心脏组织中GRK2蛋白表达;HE染色观察肝脏及肺、脾、心脏、肾脏组织学形态。结果成功鉴定Grk2^(ΔHSC)小鼠基因型;两组小鼠体质量、繁殖能力无明显差异;免疫荧光双染及Western blot结果表明,Grk2^(ΔHSC)小鼠的肝星状细胞中GRK2蛋白水平明显低于对照组小鼠,Grk2^(ΔHSC)小鼠肺、脾、肾脏和心脏组织中GRK2蛋白表达与对照组相比无明显变化;HE染色结果显示,Grk2^(ΔHSC)小鼠肝脏及主要组织结构与Grk2^(fl/fl)相比差异无显著性,可用于后续研究。结论本研究应用Cre-loxP技术成功构建了肝星状细胞特异性Grk2基因敲除小鼠,为进一步研究GRK2在肝脏中的作用提供了优良工具。

Ent-11α-Hydroxy-15-oxo-kaur-16-en-19-oic-acid Inhibits Growth of Human Lung Cancer A549 Cells by Arresting Cell Cycle and Triggering Apoptosis

Objective： To examine the apoptotic effect of ent-llα-hydroxy-15-oxo-kaur-16-en-19-oic-acid （5F）, a compound isolated from Pteris semipinnata L （PsL）, in human lung cancer A549 cells. Methods： A549 cells were treated with 5F （0-80 lag/ml） for different time periods. Cytotoxicity was examined using a Ml-I- method. Cell cycle was examined using propidium iodide staining. Apoptosis was examined using Hoechst 33258 staining, enzyme-linked immunosorbent assay （ELISA） and caspase-3 activity analysis. Expression of representative apoptosis-related proteins was evaluated by Western blot analysis. Reactive oxygen species （ROS） level was measured using standard protocols. Potential interaction of 5F with cisplatin was also examined. Results： 5F inhibited the proliferation of A549 cells in a concentration- and time-dependent manner. 5F increased the accumulation of cells in sub-G1 phase and arrested the cells in the G2 phase. Exposure to 5F induced morphological changes and DNA fragmentation that are characteristic of apoptosis. The expression of p21 was increased. 5F exposure also increased Bax expression, release of cytochrome c and apoptosis inducing factor （AIF）, and activation of caspase-3. 5F significantly sensitized the cells to cisplatin toxicity. Interestingly, treatment with 5F did not increase ROS, but reduced ROS production induced by cisplatin. Conclusion： 5F could inhibit the proliferation of A549 cells by arresting the cells in G2 phase and by inducing mitochondrial-mediated apoptosis.

Intrinsic apoptotic pathway and G2/M cell cycle arrest involved in tubeimoside I-induced EC109 cell death

Objective： Squamous esophageal carcinoma is highly prevalent in developing countries, especially in China. Tu Bei Mu （TBM）, a traditional folk medicine, has been used to treat esophageal squamous cell carcinoma （ESCC） for a long term. tubeimoside I （TBMS1） is the main component of TBM, exhibiting great anticancer potential. In this study, we investigated the mechanism of TBMS1 cytotoxic effect on EC109 cells. Methods： Comparative nuclear proteomic approach was applied in the current study and we identified several altered protein spots. Further biochemical studies were carried out to detect the mitochondrial membrane potential, cell cycle and corresponding proteins＇ expression and location. Results： Subcellular proteomic study in the nucleus from EC109 cells revealed that altered proteins were associated with mitochondrial function and cell proliferation. Further biochemical studies showed that TBMSl-induced molecular events were related to mitochondria-induced intrinsic apoptosis and P21-cyclin B 1/cdc2 complex-related G2/M cell cycle arrest. Conclusions： Considering the conventional application of TBM in esophageal cancer, TBMS1 therefore may have a great potential as a chemotherapeutic drug candidate for ESCC.

Bio-compatibility and cytotoxicity studies of water-soluble CuInS_2-ZnS-AFP fluorescence probe in liver cancer cells

BACKGROUND： The oncogenesis of hepatocellular carcinoma（HCC） is not clear. The current methods of the pertinent studies are not precise and sensitive. The present study was to use liver cancer cell line to explore the bio-compatibility and cytotoxicity of ternary quantum dots（QDs） probe and to evaluate the possible application of QDs in HCC.METHODS： CuInS_2-ZnS-AFP fluorescence probe was designed and synthesized to label the liver cancer cell HepG 2. The cytotoxicity of CuInS_2-ZnS-AFP probe was evaluated by MTT experiments and flow cytometry. RESULTS： The labeling experiments indicated that CuInS_2-ZnS QDs conjugated with AFP antibody could enter HepG 2 cells effectively and emit intensive yellow fluorescence by ultraviolet excitation without changing cellular morphology. Toxicity tests suggested that the cytotoxicity of CuInS_2-ZnS-AFP probe was significantly lower than that of CdT e-ZnS-AFP probe（t test, F=0.8, T=-69.326, P〈0.001）. For CuInS_2-ZnS-AFP probe, timeeffect relationship was presented in intermediate concentration（〉20%） groups（P〈0.05） and dose-effect relationship was presented in almost all of the groups（P〈0.05）. CONCLUSION： CuInS_2-ZnS-AFP QDs probe had better biocompatibility and lower cytotoxicity compared with CdT e-ZnS-AFP probe, and could be used for imaging the living cells in vitro.

Viral infections and cell cycle G2/M regulation

Progression of cells from G2 phase of the cell cycle to mitosis is a tightly regulated cellular process that requires activation of the Cdc2 kinase, which determines onset of mitosis in all eukaryotic cells. In both human and fission yeast (Schizosaccharomyces pombe) cells, the activity of Cdc2 is regulated in part by the phosphorylation status of tyrosine 15 (Tyr15) on Cdc2, which is phosphorylated by Wee1 kinase during late G2 and is rapidly dephosphorylated by the Cdc25 tyrosine phosphatase to trigger entry into mitosis. These Cdc2 regulators are the downstream targets of two well- characterized G2/M checkpoint pathways which prevent cells from entering mitosis when cellular DNA is damaged or when DNA replication is inhibited. Increasing evidence suggests that Cdc2 is also commonly targeted by viral proteins, which modulate host cell cycle machinery to benefit viral survival or replication. In this review, we describe the effect of viral protein R (Vpr) encoded by human immunodeficiency virus type 1 (HIV-1) on cell cycle G2/M regulation. Based on our current knowledge about this viral effect, we hypothesize that Vpr induces cell cycle G2 arrest through a mechanism that is to some extent different from the classic G2/M checkpoints. One the unique features distinguishing Vpr-induced G2 arrest from the classic checkpoints is the role of phosphatase 2A (PP2A) in Vpr-induced G2 arrest. Interestingly, PP2A is targeted by a number of other viral proteins including SV40 small T antigen, polyomavirus T antigen, HTLV Tax and adenovirus E4orf4. Thus an in-depth understanding of the molecular mechanisms underlying Vpr-induced G2 arrest will provide additional insights into the basic biology of cell cycle G2/M regulation and into the biological significance of this effect during host-pathogen interactions.

Far Infrared Ray Radiation Inhibits the Proliferation of A549, HSC3 and Sa3 Cancer Cells through Enhancing the Expression of ATF3 Gene

Far-infrared ray (FIR) is electromagnetic wave between 4 and 1000 μm. FIR causes heating, but how it affects cells is not well understood. In this study, we developed a culture incubator that can continuously irradiate cells with FIR and examined the effects of FIR on five human cancer cell lines, namely A431 (vulva), A549 (lung), HSC3 (tongue), MCF7 (breast) and Sa3 (gingiva). We found that FIR inhibits cell proliferation and induces cell hypertrophy without apoptosis in A549, HSC3 and Sa3 cells. Flow cytometry revealed that the inhibition of proliferation was due to G2/M arrest. Contrary, FIR did not inhibit cell proliferation and cause cell hypertrophy in A431 or MCF7 cells. Microarray analysis revealed that FIR suppressed the expression of cell proliferation-related and stress-responsive genes in FIR-sensitive cell lines (A549, HSC3 and Sa3). ATF3 in particular was identified as a key mediator of the FIR effect. Over-expression of ATF3 inhibited cell proliferation and knockdown of ATF3 mRNA using an antisense oligonucleotide suppressed FIR-induced growth arrest. These results indicate that a body temperature range of FIR radiation suppresses the proliferation of A549, HSC3, Sa3 cells and it appears that ATF3 play important roles in this effect.

Astragalus saponins induce apoptosis in human gastric adenocarcinoma cells via a caspase 3-dependent pathway

Objective Many Asian countries including China,Japan and Korea have very high incidence of gastric cancer,in which about 42% cases occur in China's Mainland.The precise targets and underlying mechanisms are not well understood.Our previous study revealed that Astragalus saponins(AST)showed promising effects on the suppression of the growth of HT-29 human colon cancer cells and tumor xenograft by inhibiting cell proliferation and promoting apoptosis.In the present study,we investigated the anti-carcinogenic effects of AST in AGS human gastric adenocarcinoma cells and attempted to elucidate the underlying mechanisms.Methods Growth inhibition of AGS cells was determined by using the MTT viability test.Involvement of different members of the apoptotic cascade and other growth-related factors was explored by assessment of their protein expression using Western blot analysis.Distribution of cells in different phases of the cell cycle was assessed by flow cytometry.Results Our data indicate that AST induced growth-inhibition and apoptosis in AGS cells by activating caspase 3 with subsequent poly(ADP-ribose)polymerase(PARP)cleavage.Cell cycle arrest at the G2/M phase had been observed in AST-treated AGS cells.The anti-proliferative effect of AST was associated with modulation of cyclin B1 and p21.We then demonstrate that AST could downregulate the expression of VEGF,of which interaction with its receptors is important for angiogenesis during tumor formation.Conclusions Our findings suggest that AST is an effective agent in gastric cancer treatment by inducing cell cycle arrest and apoptosis,of which anti-angiogenesis could be an alternative mode of action.

Research on cell cycle retardation, apoptosis and the expression of antioncogene p57^(Kip2) by radioactive rays in nasopharyngeal carcinoma cell line in vitro

Objective: To study cell cycle retardation, apoptosis and the expression of antioncogene p57kip2 by radioactive rays in nasopharyngeal carcinoma cells. Methods: Cell cycle retardation, apoptosis and cell survival rate induced by radioac- tive rays were tested by the methods of flow cytometry and MTT method. The expression of antioncogene p57kip2 was detected by immunohistochemistry and Western blot. Results: After irradiation, G1 phase had no obvious retardation, S phase showed transient delay. There was a positive correlation between irradiation dosage and retardation strength in G2/M phase (P < 0.01). Peak value appeared at 24 h after 12 Gy irradiation, then decreased. There was a positive correlation between apop- tosis incidence and irradiation dosage or after-irradiation time extention (P < 0.01). There was a negative correlation between cell survival rate and irradiation dosage or apoptosis incidence (P < 0.01). The expression of p57kip2 protein was up-regulated along with the prolongation of time and dosage after irradiation (P < 0.01). Conclusion: G2/M phase arrest, apoptosis and the up-regulation of the expression of p57kip2 protein all can reflect predict the radiosensitivity of nasopharyngeal carcinoma cells.

苦参碱通过诱导NKG2D配体高表达增强NK细胞对ABCG2high耐药鼻咽癌细胞杀伤活性

目的探讨苦参碱提高ABCG2High[三磷酸腺苷(ATP)结合转运蛋白G超家族成员2]耐药鼻咽癌细胞对Allo-NK细胞杀伤敏感性的机制。方法利用免疫磁珠技术分离ABCG2HighCNE2/DDP细胞及Allo-NK细胞,流式细胞技术检测分离后细胞纯度及经苦参碱处理前后靶细胞NKG2D配体表达率,LDH释放测定法检测经苦参碱处理前后ABCG2HighCNE2/DDP细胞对Allo-NK细胞的杀伤敏感性。结果ABCG2HighCNE2/DDP细胞分离后ABCG2表达率为(91.40±2.32)%,分选后NK细胞CD3-CD16+CD56+细胞的纯度达90%以上,经苦参碱处理之后靶细胞MICA、MICB、ULBP1、ULBP2、ULBP3表达率,由药物处理之前的(2.92±0.33)%、(4.27±0.33)%、(5.80±0.62)%、(11.10±3.15)%、(7.75±1.14)%分别上升到(11.30±0.89)%、(14.29±2.61)%、(12.56±1.06)%、(43.24±4.43)%、(12.77±1.06)%。在效靶比为10:1、20:1,Allo-NK细胞对苦参碱处理前后ABCG2HighCNE2/DDP细胞的杀伤率分别为(15.32±1.34)%、(27.26±6.81)%及(28.53±1.37)%、(42.72±2.80)%。处理前后杀伤率有显著性差异(F=29.05,P=0.000)。结论苦参碱通过诱导肿瘤细胞高表达NKG2D配体(MICA/B、ULBP1-3),使肿瘤细胞对Allo-NK细胞的杀伤敏感性增强。

金雀异黄素抑制人胃癌细胞增殖与G_2/M期阻滞作用的体外研究

目的 : 研究金雀异黄素 (genistein,Gen)对人胃癌 SGC-790 1细胞增殖抑制作用及对细胞周期的影响。方法 : 采用3H-Td R掺入液闪计数法观察 Gen对人胃癌细胞增殖影响 ,流式细胞仪分析细胞周期分布 ,免疫组化和 Western Blotting分别检测 cyclin B、P2 1 waf1 / cip1 蛋白表达情况。结果 : Gen对胃癌细胞生长有显著抑制作用 ,使细胞生长停滞于 G2 / M期 ,并使细胞cyclin B、P2 1 waf1 / cip1蛋白表达增加 ,且呈剂量 -效应关系。结论 : Gen在此剂量下抑制胃癌细胞增殖、诱导 G2 / M期阻滞与其稳定 cyclin B蛋白和上调 P2 1 waf1 / cip1

人参皂苷CK诱导人肝癌HepG-2细胞凋亡的研究

目的探讨人参皂苷CK对人肝癌HepG-2细胞凋亡的作用及机制。方法采用MTT法测定不同浓度(30,60,90μmol/L)人参皂苷CK对人肝癌HepG-2细胞的增殖抑制作用;通过HE染色、AO/EB染色观察人参皂苷CK诱导人肝癌HepG-2细胞凋亡的形态学变化;WesternBlotting检测凋亡相关蛋白P53、Bax和Bcl-2的表达情况。结果人参皂苷CK可明显抑制人肝癌HepG-2细胞的增殖,且呈剂量依赖性和时间依赖性。随着人参皂苷CK给药浓度的增加,出现典型凋亡形态特征的细胞逐渐增多,抗凋亡蛋白Bcl-2和P53表达量逐渐下降,而促凋亡蛋白Bax的表达逐渐升高,Bcl-2/Bax比例明显降低。结论人参皂苷CK可诱导人肝癌HepG-2细胞凋亡,其作用机制可能与下调P53蛋白表达和降低Bcl-2/Bax比例有关。

TSG-6调控PI3K/Akt-Bcl-2通路影响人瘢痕疙瘩凋亡机制的研究

目的研究瘢痕疙瘩形成中肿瘤坏死因子α刺激基因6(TSG-6)调控3-磷酸肌醇激酶/丝/苏氨酸蛋白激酶-B淋巴细胞瘤-2基因(PI3K/Akt-Bcl-2)信号通路对成纤维细胞表达和凋亡的关联性。方法构建p LVX-puro-TSG-6、p LVX-shRNA1-TSG-6及其对应空质粒重组慢病毒载体转入人瘢痕疙瘩成纤维(HKF)细胞,建立稳定转染的过表达细胞株、干扰细胞株、过表达对照细胞株、干扰对照细胞株,用流式细胞术和CCK-8法分别检测相应细胞株与HKF细胞凋亡与增殖。应用RT-PCR及Western blot分别检测TSG-6过表达细胞株、TSG-6干扰组细胞株及前两组对应对照组细胞株、HKF细胞株中PI3K、Akt、鼠双微基因2(MDM2)、P53基因、Bcl-2的信使核糖核酸及蛋白表达变化。结果与HKF组对比,TSG-6过表达组细胞增殖减缓,凋亡显著增加(t=-4.443,P=0.011);TSG-6干扰组则相反(t=3.827,P=0.019);其余各组间差异无统计学意义。RT-PCR、Western blot检测结果显示TSG-6过表达组抑制PI3K、Akt、MDM2、Bcl-2的mRNA及蛋白表达,促进P53的mRNA及蛋白表达(P<0.05)。TSG-6干扰组促进PI3K、Akt、MDM2、Bcl-2的mRNA及蛋白表达,抑制P53的mRNA及蛋白表达(P<0.05)。结论 TSG-6负向调控PI3K/Akt-Bcl-2通路促进HKF细胞凋亡,抑制瘢痕疙瘩增生。

苦参碱对高表达ABCG2人耐药鼻咽癌细胞NKG2D配体表达的诱导作用

目的：探讨苦参碱对高表达三磷酸腺苷（ATP）结合转运蛋白G超家族成员2（ABCG2）人耐药鼻咽癌细胞CNE2／DDP（简写作ABCG_2H^High CNE2／DDP）NKG2D配体表达的诱导作用及其对NK细胞杀伤敏感性的机制。方法：利用免疫磁珠技术分离ABCG_2^High CNE2／DDP细胞及NK细胞，流式细胞技术检测分离后细胞纯度及经苦参碱处理前后靶细胞NKG2D配体表达率，LDH释放测定法检测经苦参碱处理前后ABCG_2^High CNE2／DDP细胞对NK细胞的杀伤敏感性。结果：ABCG_2^High CNE2／DDP细胞分离后ABCG2表达率为（91．40±2．32）％，分选后NK细胞CD3^-CD16^＋CD56^＋细胞的纯度达90％以上，经苦参碱处理之后靶细胞MICA、MICB、ULBP1、ULBP2、ULBP3表达率，由药物处理之前的（2．92±0．33）％、（4．27±0．33）％、（5．80±0．62）％、（11．10±3．15）％、（7．75±1．14）％分别上升到（11．30±0．89）％、（14．29±2．61）％、（12．56±1．06）％、（43．24±4．43）％、（12．77±1．06）％。在效靶比为10：1、20：1时，NK细胞对苦参碱处理前后ABCG^2^High CNE2／DDP细胞的杀伤率分别为（15.32±1．34）％、（27．26±6．81）％及（28．53±1．37）％、（42．72±2．80）％。处理前后杀伤率有显著性差异（F=29．05，P=0．000）。结论：苦参碱通过诱导肿瘤细胞高表达NKG2D配体（MICA/B、ULBP1-3），使肿瘤细胞对NK细胞的杀伤敏感性增强。