抗坏血酸与DL—α—生育酚对人肝癌细胞增殖与再分化的作用

目的:测定抗坏血酸(AA)和DL-α-生育酚(αT)联合处理对人肝癌细胞增殖与再分化的作用。方法:维甲酸(RA)为阳性对照。用细胞表面电荷、生化变化和软琼脂细胞生长等指标测定细胞分化和增殖。结果:用AA 4 mmol·L~(-1)和αT 1 mmol·L~(-1)联合处理后,肝癌细胞的生长和分裂指数显著下降,增殖抑制率达61.3％。与恶化有关的指标显著减轻,如细胞表面电荷明显降低,电泳率从1.63 μm·s~(-1)·V~(-1)·cm~(-1)降低到0.89,甲胎蛋白由300μg·g~(-1)(protein)降到80,γ-谷氨酰转肽酶活性由0.81 U·g~(-1)(protein)降到0.201。与分化相关的酪氨酸-α-酮戊二酸转氨酶活性显著上升,由10.6μmol·g~(-1)(protein)升高到45,细胞克隆形成力降低96.6％。结论:AA和αT合用能够抑制人肝癌细胞增殖,诱导分化,并逆转恶性表型。     

Effects of ascorbic acid and sodium selenite on growth and redifferentiation in human hepatoma cells and its mechanisms

After being treated with ascorbic acid (AA) 3 mM + sodium selenite (SS) 1.5 microM, the growth rate and mitotic index of human hepatoma cells BEL-7402 decreased remarkably. The indexes related to cell malignancy were improved, such as cell surface charge obviously decreased, the electrophoresis rate fell from 1.76 microns.s-1.V-1.cm-1 to 0.93, the average of alpha-fetoprotein (alpha-FP) content decreased from 341 micrograms.g-1 protein to 92, and gamma-glutamyl-transpeptidase (gamma-GT) activity from 0.76 U.g-1 protein to 0.19. The indexes related to cell differentiation were affected favourably, such as the level of tyrosine-alpha-ketoglutarate transaminase (TAT) activity increased from 14.2 mumol.g-1 protein to 49.0, and the colonogenic potential decreased 95.3%. These results indicated that hepatoma cells had been successfully induced to redifferentiation by AA + SS. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were significantly higher, while the activity of catalase (CAT) was slower in the treated group than in the control group. The malondialdehyde (MDA) content decreased slightly, reduced glutathione (GSH) decreased sharply, and H2O2 content increased dramatically. In conclusion, these results indicate that the combination of ascorbic acid and sodium selenite may induce the redifferentiation of hepatoma cells and inhibit cell growth by virtue of enhancing the activities of antioxidative enzymes and reducing the formation of H2O2, and altering the cell redox status. The combination of ascorbic acid and sodium selenite may be a potent anticancer treatment option for human hepatoma cells.     

Ascorbic acid induces redifferentiation and growth inhibition in human hepatoma cells by increasing endogenous hydrogen peroxide

The mechanisms of redifferentiation and growth inhibition induced in human hepatoma cells by ascorbic acid (AA) were studied. After treatment with AA, the content of hydrogen peroxide (H2O2) and the activity of superoxide dismutase (SOD) increased in a concentration- and time-dependent manner, while the activity of catalase (CAT) decreased in a concentration- and time-dependent manner. Using 6 mM AA as a positive control, after treatment by 50 microM hydrogen peroxide, the malignant characteristics of human hepatoma cells were alleviated; for example as cell surface charge markedly decreased, the electrophoresis rate dropped from 1.68 microns.s-1.V-1.cm-1 to 0.97, the average of alpha-fetoprotein content decreased from 327 micrograms.g-1 protein to 193, and gamma-glutamyl-transpeptidase activity fell from 0.84 U.g-1 protein to 0.30. The indexes related to cell differentiation were promoted, such as tyrosine-alpha-ketoglutarate transaminase activity increased from 17.1 mumol.g-1 protein to 33.1, and the colonogenic potential decreased by 79.3%. SOD and 3-amino-1,2,4-triazole (AT) exhibited some effects, but there were statistically significant differences between the SOD, AT and H2O2 or AA groups. AA induced growth inhibition and redifferentiation of human hepatoma cells through the production of hydrogen peroxide, since addition of SOD (200 units/ml), an enzyme that dismutates superoxide and generates hydrogen peroxide, and AT (1.5 mM), a CAT inhibitor that inhibits the activity of CAT and leads to an increase in H2O2 content, showed some inducing changes emphasizing the involvement of reactive oxygen species (ROS) in redifferentiation of hepatoma cells. AA can cause the content of H2O2 to increase, and the factor H2O2 showed a similar effect to AA on growth and redifferentiation suggests that H2O2 is involved in hepatoma cell redifferentiation. In conclusion, these results suggest that AA inhibits tumor growth and induces tumor redifferentiation by virtue of producing H2O2.     

Effects of diethyldithiocarbamate on proliferation, redifferention, and apoptosis in human hepatoma cells.

AIM: To examine the effects of diethyldithiocarbamate (DDC) on the proliferation, redifferentiation, and apoptosis in human hepatoma cells. METHODS: Cell surface charge, biochemical changes, cell growth in soft agar, single cell electrophoresis, electron microscopy examination, and flow cytometry analysis were measured. RESULTS: After being treated with DDC 3 mmol/L the growth curve and mitotic index of human hepatoma cells decreased remarkably, and the cellular growth inhibitory rate amounted to 52.4 %. The indices related with cell malignancy were alleviated significantly, such as the cell surface charge decreased significantly, the electrophoresis rate dropped from 1.6 to 0.8 micron . s-1 . V-1 . cm-1, the average value of alpha-fetoprotein (alpha-FP) content decrease d from 314 to 95 microg/g (protein), and gamma-glutamyl-transpeptidase (gamma-GT) activity from 0.9 to 0.14 U/g (protein). The cell differentiation index increased significantly, such as the average levels of tyrosine-alpha-ketoglutarate transaminase (TAT) activity increased from 11.6 to 36 micromol/g (protein), and the colonogenic potential decreased by 95.6 %. The apoptotic bodies, detached cells, and apoptotic morphological features appeared, and the treated cells DNA was fragmented as observed by the comet assay. The flow cytometric results showed that a 42.9 % fractional DNA content existed in the treated cells. CONCLUSION: DDC can inhibit human hepatoma cells proliferation, and can induce redifferentiation as well as apoptosis.     

Redifferentiation of human hepatoma cell induced by 6-(p-chlorophenyl)-3-[1-(p-chlorophenyl)-5-methyl-1 H-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazole (TDZ)

6-(p-Chlorophenyl)-3-[1-(p-chlorophenyl)-5-methyl-1 H-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazole (TDZ) is a derivative of various substituted s-triazolo[3,4-b]-1,3,4-thiadiazoles, which are associated with diverse pharmacological activities. However, the antitumor activity of TDZ is not well understood. To evaluate its role on tumor cell lines, we have examined the effect of TDZ on two tumor lines: human hepatoma cell (SMMC-7721) in vitro and Sarcoma180 tumor (S180) in vivo. The cytotoxicity of TDZ on human hepatoma cells was assessed using the MTT assay. The inhibition on tumor growth was evaluated by means of trypan blue exclusion test in vitro, and using a Sarcoma180 tumor (S180) animal model in vivo. A scanning electronic microscope was used to discover the morphological changes on cell surface, cell electrophoresis was employed to determine the changes of cell surface negative charges, and alpha-fetoprotein was applied as a biomarker of hepatoma. The effect of TDZ on DNA synthesis was determined by a [3H]-thymidine incorporation assay, and cell cycle distribution by flow cytometry. The IC50 value of TDZ on SMMC-7721 cells was 52.9 microg/ml (48 h). However, TDZ could inhibit the growth of SMMC-7721 cells at concentrations far lower than the IC50 value. Treated with the same low concentrations of TDZ, microvilli on the surface of SMMC-7721 cells decreased obviously, electrophoresis rate of cells reduced from 2.14 microm ms(-1) x V(-1) x cm(-1) of control to 1.54 and 1.56 microm x s(-1) x V-1 x cm(-1), the content of AFP dropped from 205.14 +/- 6.41 ng x mg(-1) Pr to 115.68 +/- 3.47 and 78.57 +/- 2.35 ng mg(-1) Pr, and the DNA replication was inhibited by 26.8% and 45.2%. These results indicated that TDZ may inhibit proliferation of cancer cells by reversing SMMC-7721 cells malignant phenotypic characteristics and inducing redifferentiation. Flow cytometry showed that TDZ-treated cells resulted in a higher proportion of cells in S phase compared with untreated cells, and only when the concentration reached 64 microg/ml, the apoptosis could happen at the rate of 4.2%. Detection of the inhibition of Sarcoma 180 tumor growth in vivo showed that TDZ reduced the tumor weight and 69.08% of the growth was inhibited. TDZ could inhibit the proliferation of tumors in vitro and in vivo; the possible antitumor mechanism might be inducing redifferentiation at a lower dosage on vitro.     

紫杉醇体外抗肝癌活性(英文)

目的:研究紫杉醇在体外对SMMC-7721人肝癌细胞的抑制作用及其机理。方法:用MTT比色法测定细胞生长。用流式细胞仪及显微镜观察进行细胞周期动力学和凋亡的分析。结果:紫杉醇抑制人肝癌细胞生长的IC_(50)为18.96nmol·L~(-1),并有一定的浓度和时间依赖关系。经紫杉醇10nmol·L~(-1)处理后细胞积聚在G_2/M期并发现明显的凋亡,形态学观察可见多个多核细胞。结论:紫杉醇通过引起细胞周期阻滞、异常的有丝分裂以及细胞凋亡抑制人肝癌细胞生长。     

氧代赖氨酸对肝癌细胞生长、AFP分泌及γ-GT活性的抑制作用

目的研究氧代赖氨酸（Ｌ ４ ｏｘａｌｙｓｉｎｅ，ＯＸＬ）对人肝癌细胞体内、外生长及其对甲胎蛋白（ＡＦＰ）分泌和γ 谷氨酰转肽酶（γ ＧＴ）活性的影响。方法以ＭＴＴ法测定ＯＸＬ的体外抗肝癌活性。以裸小鼠异种移植人肝癌模型观察药物的体内抗肝癌作用。以酶联免疫法（ＥＬＩＳＡ）检测ＡＦＰ水平。以酶底物法检测γ ＧＴ活力。结果①ＯＸＬ０８～６８×１０－４ｍｏｌ·Ｌ－１作用６ｄ，对体外培养的３种人肝癌ＨｅｐＧ２、Ｂｅｌ ７４０２和Ｂｅｌ ７４０４细胞株仅有微弱的生长抑制作用，６８×１０－４ｍｏｌ·Ｌ－１时的抑制率为１３７％～４５６％。②ＯＸＬ２００ｍｇ·ｋｇ－１，ｐｏ，ｑｄ×２ｗｋ对裸小鼠异种移植人ＨＣＣ ９３实体型肝癌的生长有明显抑制作用，抑瘤率为４３５％（Ｐ＜００５）。③ＯＸＬ能明显抑制人肝癌细胞ＡＦＰ分泌量和γ ＧＴ酶活力，丝裂霉素Ｃ在治疗剂量时能明显抑制人肝癌的生长，并使γ ＧＴ的活性显著降低，但对ＡＦＰ的抑制作用却较弱。结论ＯＸＬ的体内抗人肝癌活性较体外强，其作用与１９９８ ０６ ２４收稿，１９９８ １１ １８修回国家自然科学基金资助项目，Ｎｏ３９５７０８２４作者简介：章雄文，男，３４岁，博士?     

Baicalein inhibits the migration and invasive properties of human hepatoma cells

Flavonoids have been demonstrated to exert health benefits in humans. We investigated whether the flavonoid baicalein would inhibit the adhesion, migration, invasion, and growth of human hepatoma cell lines, and we also investigated its mechanism of action. The separate effects of baicalein and baicalin on the viability of HA22T/VGH and SK-Hep1 cells were investigated for 24 h. To evaluate their invasive properties, cells were incubated on matrigel-coated transwell membranes in the presence or absence of baicalein. We examined the effect of baicalein on the adhesion of cells, on the activation of matrix metalloproteinases (MMPs), protein kinase C (PKC), and p38 mitogen-activated protein kinase (MAPK), and on tumor growth in vivo. We observed that baicalein suppresses hepatoma cell growth by 55%, baicalein-treated cells showed lower levels of migration than untreated cells, and cell invasion was significantly reduced to 28%. Incubation of hepatoma cells with baicalein also significantly inhibited cell adhesion to matrigel, collagen I, and gelatin-coated substrate. Baicalein also decreased the gelatinolytic activities of the matrix metalloproteinases MMP-2, MMP-9, and uPA, decreased p50 and p65 nuclear translocation, and decreased phosphorylated I-kappa-B (IKB)-β. In addition, baicalein reduced the phosphorylation levels of PKCα and p38 proteins, which regulate invasion in poorly differentiated hepatoma cells. Finally, when SK-Hep1 cells were grown as xenografts in nude mice, intraperitoneal (i.p.) injection of baicalein induced a significant dose-dependent decrease in tumor growth. These results demonstrate the anticancer properties of baicalein, which include the inhibition of adhesion, invasion, migration, and proliferation of human hepatoma cells in vivo.