Melatonin and Doxorubicin synergistically induce cell apoptosis in human hepatoma cell lines

AIM:To investigate whether Melatonin has synergistic effects with Doxorubicin in the growth-inhibition and apoptosis-induction of human hepatoma cell lines HepG2 and Bel-7402.METHODS:The synergism of Melatonin and Doxorubicin inhibited the cell growth and induced cell apoptosis in human hepatoma cell lines HepG2 and Bel-7402.Cell viability was analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide(MTT)assay.Cell apoptosis was evaluated using TUNEL method and flow cytometry.Apoptosis-related protein Bax,Bcl-2 and caspase-3 expressions were measured by immunohistochemical staining.RESULTS:Treatment with Melatonin(10 -8 -10 -5 mol/L) alone had a dose-related inhibitory effect on cell proliferation but no cytotoxic effect on hepatoma cell lines HepG2 and Bel-7402.Interestingly,when combined with Doxorubicin,Melatonin significantly increased the effects of cell growth inhibition and cell apoptosis.Furthermore,TUNEL staining and flow cytometry revealed that cooperative apoptosis induction was associated with decreased expression of Bcl-2 as well as increased expression of Bax and Caspase3.CONCLUSION:The synergism of Melatonin and Doxorubicin inhibits hepatoma cell growth and induces cell apoptosis.

Using a non-radioisotopic, quantitative TRAP-based method detecting telomerase activities in human hepatoma cells

A non-radioisotopic, quantitative TRAP-based telomerase activity assay was established mainly by using SYBR Green-I staining instead of radioisotope. Comparing with conventional radioisotope based method, it was better in reproducibility and accuracy. Using this method, we found telomerase activities were absent in normal human liver cells, while detected in ail of four human hepatoma cell lines (BEL-7404, SMMC-7721, QGY-7903 and HCCM) without significant differences.

Inhibitory effect of parvovirus H-1 on the formation of colonies of human hepatoma cell line in vitro and its tumors in nude mice

The inhibitory effect of parvovirus H-1 on the colonyforming ability in vitro of QGY-7703, a cultured human hepatoma cell line, and on the formation and growth of its tumors in nude mice was studied. With higher multiplicity of infection (MOI) of H-1 given, survival of the QGY-7703 cells was found to be decreased. H-1 DNA amplification level at 30 h postinfection(p.i.) was detected to be 7.4 times higher than that at 2 h by dispersed cells assay, while the cells were delayed to enter into S phase.Plaques were formed in the indicator cells (new-born human kidney cell line, NBK) by progeny H-1 virus particles released from the infected QGY-7703 cells by infectious cell center assay. The formation of tumors in nude mice by QGY-7703 cells which were injected s c at 2 h postinfection was observed to be prevented in 2 groups with given MOI 25 and 50. The tumor growth of MOI 10 group occurred at a lower exponential rate than that of control,after a 20 d latent period. It was evident that parvovirus H-1 exhibited a direct inhibitory effect on the formation and growth of human hepatoma cells in vivo as well as in vitro.

Effect of 80.55 MeV//u^(12)C^(6+) Ions on Radiosensitivity and Cell Cycle of Human Hepatoma Cell Lines

In this paper, the relationship between radiosensitivity, cell cycle alteration and the change of apoptosis in different human hepatoma cell lines irradiated by heavy ions were studied with the aim of building up the base data for clinical therapy. Exponentially growing hepatoma cell lines were irradiated by 80.55 MeV/u12C6＋ ions at a dose of 0 Gy, 0.5 Gy, 1 Gy, 2 Gy, 4 Gy and 8 Gy. The radiosensitivity was assessed by means of the colony-forming assay. The DNA content, the percentage of each cell-cycle phase and the apoptosis rate were obtained with flow cytometry methods. After the irradiation, the SF2 （survival fraction at 2 gray） of SMMC-7721 cells were evidently lower than that of HepG2 cells. The S phase arrest, G2/M phase arrest delay and the apoptosis in the two hepatoma cell lines varied with the increase of the dose and repair time. The heavy ions could obviously kill the human hepatoma cell lines. Compared to HepG2 cells, SMMC-7721 cells were more radiosensitive to 12C^6＋ ions.

Effects of Terminalia arjuna bark extract on apoptosis of human hepatoma cell line HepG2

AIM：To investigate the effects of Terminalia arjuna （T. arjuna） extract on human hepatoma cell line （HepG2） and its possible role in induction of apoptosis.METHODS： Human hepatoma cells were treated with different concentrations of ethanolic extract of T. arjuna and its cytotoxicity effect was measured by trypan blue exclusion method and lactate dehydrogenase leakage assay. Apoptosis was analyzed by light and fluorescence microscopic methods, and DNA fragmentation. The mechanism of apoptosis was studied with expression of p53 and caspase-3 proteins. Glutathione （GSH） content was also measured in HepG2 cells after T. arjuna treatment.RESULTS： T. arjuna inhibited the proliferation of HepG2 cells in a concentration-dependent manner. Apoptotic morphology was observed in HepG2 cells treated with T. arjuna at the concentrations of 60 and 100 mg/L. DNA fragmentation, accumulation of p53 and cleavage of procaspase-3 protein were observed in HepG2 cells after the treatment with T. arjuna. The depletion of GSH was observed in HepG2 cells treated with T. arjuna.CONCLUSION： T. arjuna induced cytotoxicity in HepG2 cells in vitro. Apoptosis of HepG2 cells may be due to the DNA damage and expression of apoptotic proteins. Depletion of GSH may be involved in the induction of apoptosis of HepG2 cells.

ApoB-containing lipoproteins promote infectivity of chlamydial species in human hepatoma cell line

AIM:To evaluate the direct binding of two main chlamydial biovars(C.trachomatis and C.pneumoniae) to plasma lipoproteins and its effect on chlamydial infection rate in human hepatoma cell line(HepG2 cells). METHODS:Murine plasma lipoproteins were fractionated and isolated using fast-performance liquid chromatography(FPLC),spotted on nitrocellulose membrane and incubated with chlamydial suspensions. Direct binding of chlamydial particles to lipoprotein fractions has been studied using lipopolysaccharide-specific antibodies in immuno-dot blot binding assay and immunoprecipitation analysis.Immunostaining protocol as well as flow cytometry analysis have been employed to study the infectivity rate of chlamydial species in HepG2 cells. RESULTS:Elementary bodies of both C.trachomatis and C.pneumoniae bind ApoB-containing fractions of plasma lipoproteins.That binding becomes stronger when heat-denatured FPLC fractions are used, suggesting a primary role of apolipoproteins in interaction between chlamydial particle and lipoprotein. Both chlamydial biovars efficiently propagate in human hepatoma cell line-HepG2 cells even in serum free conditions forming late-stage inclusion bodies and releasing extracellular elementary bodies.Preincubation of C.trachomatis and C.pneumoniae with native ApoB-containing lipoproteins enhances the rate of chlamydial infection in HepG2 cells.CONCLUSION:A productive infection caused by C. trachomatis and C.pneumoniae may take place in human-derived hepatocytes revealing hepatic cells as possible target in chlamydial infection.Obtained results may suggest the participation of lipoprotein receptors in the mechanism of attachment and/or entry of chlamydial particles into target cells.

Effects of basic fibroblast growth factor on angiogenin expression and cell proliferation in H7402 human hepatoma cells

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Basic fibroblast growth factor (bFGF), which is highly expressed in developing tissues and malignant cells, regulates cell growth, differentiation, and migration. Its expression is essential for the progression and metastasis of HCC. This study aims to investigate the effects of bFGF on the expression of angiogenin, another growth factor, which plays an important role in tumor angiogenesis, and on cell proliferation in H7402 human hepatoma cells. The bFGF sense cDNA or antisense cDNA was stably transfected into H7402 cells. Genomic DNA PCR analysis demonstrated that human bFGF sense cDNA or antisense cDNA was inserted into the genome. Furthermore, the expression of bFGF and angiogenin was examined by RT-PCR and Western blot assays. MTT and colony formation assays were employed to determine cell proliferation. Stable bFGF over-expressing and under-expressing transfectants were successfully established. Expression of angiogenin was decreased in the over-expressing bFGF cells (sense transfectants) and was increased in the under-expressing bFGF cells (antisense transfectants). Cell proliferation increased in the bFGF sense transfectants and decreased in the bFGF antisense transfectants. These results demonstrated that the endogenous bFGF may not only negatively regulate the angiogenin expression but also contribute to the overall cell proliferation in H7402 human hepatoma cells. This study may be helpful in finding a potential therapeutic approach to HCC.

Thapsigargin increases apoptotic cell death in human hepatoma BEL-7404 cells

Effects of thapsigargin, an inhibitor of Ca2+-ATPase in surface of endoplasmic reticulum, on apoptotic cell death were studied in human hepatoma cells of BEL-7404 cell line by using both flow cytometry and electron mi-croscopy Propidium iodide staining and flow cytome- try revealed that in the serum-free condition, thapsigar-gin increased the rate of apoptosis of BEL- 7404 cells in a dose-dependent manner. Prolongation of the period of serum-free condition enhanced the apoptosis induced by thapsigargin treatment. Morphological observation with electron microscope further demonstrated that chromatin condensation and fragmentation, apoptotic bodies existed in TG-treated cells, supporting that thapsigargin is a po-tent activator of apoptosis in the cells.

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.

Exogenous phosphatidylethanolamine induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway

AIM: To investigate the signaling pathways implicated in phosphatidylethanolamine (PE)-induced apoptosis of human hepatoma HepG2 cells. METHODS: Inhibitory effects of PE on human hepatoma HepG2 cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle, apoptosis and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry. Immunocytochemical assay and Western blotting were used to examine Bcl-2, Bax and caspase-3 protein levels in HepG2 cells treated with PE. RESULTS: PE inhibited the growth of HepG2 cells in a doseand timedependent manner. It did notaffect the cell cycle, but induced apoptosis. PE significantly decreased ΔΨm at 0.25, 0.5 and 1 mmol/L, respectively, suggesting that PE induces cell apoptosis by decreasing the mitochondrial transmembrane potential. The Bcl-2 expression level induced by different concentrations of PE was lower than that in control groups. However, the Bax expression level induced by PE was higher than that in the control group. Meanwhile, PE increased the caspase-3 expression in a doseand time-dependent manner. CONCLUSION: Exogenous PE induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway.

Molecular mechanisms of apoptosis induced by Scorpio water extract in human hepatoma HepG2 cells

AIM: To clarify the mechanism underlying the anti-mutagenic and anti-cancer activities of Scorpio water extract (SWE). METHODS: Human hepatoma HepG2 cells were incubated with various concentrations of SWE. After 24-h incubation, cytotoxicity and apoptosis evaluations were determined by MTT and DNA fragmentation assay, respectively. After treatment with SWE, mitochondrial membrane potential (MMP) was determined by measuring the retention of the dye 3,3'-dihexyloxacarbocyanine (DiOC6(3)) and the protein expression including cytochrome C and poly-(ADPribose) polymerase (PARP) were measured by Western blotting. Caspase-3 and -9 enzyme activities were measured using specific fluorescence dyes such as Ac-DEVD-AFC and Ac-LEHD-AFC. RESULTS: We found that treatment with SWE induced apoptosis as confirmed by discontinuous DNA fragmentation in cultured human hepatoma HepG2 cells. Our investigation also showed that SWE-induced apoptosis of HepG2 cells were associated with intracellular events including disruption of MMP, increased translocation of cytochrome C from mitochondria to cytosol, activation of caspase-3, and PARP. Pre-treatment of N-acetyl-Asp-Glu-Val-Asp-CHO (Ac-DEVD-CHO), a caspase-3 specific inhibitor, or cyclosporin A (CsA), an inhibitor of MMP disruption, completely abolished SWE-induced DNA fragmentation. CONCLUSION: These results suggest that SWE possibly causes mitochondrial damage, leading to cytochrome C release into cytosol and activation of caspases resulting in PARP cleavage and execution of apoptotic cell death in HepG2 cells. These results further suggest that Scorpio may be a valuable agent of therapeutic intervention of human hepatomas.

Two-dimensional gel electrophoresis analysis of the proteomes expressed in the human hepatoma cell line BEL-7404 and normal liver cell line L-02

Proteome analysis technology has been used extensively in conducting discovery research of biology and has become one of the most essential technologies in functional genomics. The proteomes of the human hepatoma cell line BEL-7404 and the normal human liver cell line L-02 have been separated by high resolution two-dimensional gel electrophoresis (2-DE) with immobilized pH gradient isoelectric focusing (IPG-IEF) in the first dimension and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in the second dimension (IPG-DALT). The resulting images have been analyzed using 2-D analysis software. Quantitative analysis reveals that 7 protein spots are detected only in hepatoma BEL-7404 cells, 14 only in L-02 cells, and 78 protein spots show significant fluctuation in quantity in both cell lines (P【0.01). These protein spots have been displayed on a proteome differential expression map. Analysis for the reproducibility of 2-DE indicates that the positional variability in the IEF dimension

Effect of P145^(INK4b/MTS2) on the proliferation of human hepatoma cells SMMC-7721

The full length cDNA coding for P15 INK4b, which is a cyclin-dependent kinase inhibitor, was cloned to plasmid PXJ41-neo (Eco R I IXho 1 site) and the new constructed plasmid pXJp15 was obtained. pXJp15 was transferred into the human hepatoma SMMC-7721 cells by lipofectine reagent. After G418 selection, a series of cell lines stably expressing high levels of P15 (named SHT) and the clone containing vector PXJ41-neo only (named SVXJ) were obtained by Northern and Western analysis. The results showed that the proliferation of SHT cells is inhibited compared with that of SVXJ cells. Cell cycle analysis indicated that overexpressing of P15 inhibited the growth of SHT cells by decreasing progrssion of cells from G1 to S and G2 to M phases. The levels of c-Myc and c-Fos were obviously decreased in SHT cells compared with control cells by Western blotting. The decreased expression of oncogene may be one of the molecular mechanisms of the effect of P15 on the proliferation of in SHT cells.

mad-overexpression down regulates the malignant growth and p53 mediated apoptosis in human hepatocellular carcinoma BEL-7404 cells

Mad protein has been shown as an antagonist of cMyc protein in some cell lines. The effect of Mad protein to the malignant phenotype of human hepatoma BEL7404 cell line was investigated experimentally. An eukarryotic vector pCDNA Ⅲ containing full ORF fragmentof mad cDNA was transfected into targeted cells. Under G418 selection, stable Mad-overexpressed cells were cloned.Studies on the effect of Mad over-expression in cell proliferation and cell cycle revealed that cell morphology of the Mad-overexpressed BEL-7404-M1 cells was significantly different from the parent and control vector transfected cells. DNA synthesis, cell proliferation and anchorage-independent growth in soft-agar of the madtransfected cel1s were partially inhibited in comparison to control cells.Flow Cytometry analysis indicated that mad over-expression might block more transfectant cells at G0/G1 phase, resulting in the retardation of cell proliferation. RT-PCR detected a marked inhibition of the expression of cdc25A, an important regulator gene of G0/G1to S phase in cell cycle. It was also found that Mad protein overexpression could greatly suppress p53-mediated apoptosis in BEL-7404-M1 cells in the absence of serume.Thus, Mad proteins may function as a negative regulator antagonizing c-Myc activity in the control of cell growth and apoptosis in human hepatocellular carcinoma BEL7404 cells.madoverexpression and regulation of cell growth and apoptosis

和枢消积方对人肝癌细胞系HepG2增殖凋亡的影响

目的探讨和枢消积方对人肝癌细胞系HepG2增殖凋亡的影响,揭示可能的分子机制。方法使用和枢消积方作用于人肝癌细胞系HepG2,采用Cell Counting Kit-8(CCK-8)、平板克隆实验检测细胞增殖能力。采用蛋白质印迹法(Western blot)检测B淋巴细胞瘤-2基因(BCL-2)、BCL-2相关X蛋白(BAX)、丙型肝炎病毒(HCV)非结构5A蛋白(NS5A)反式激活基因13(NS5ATP13)及蛋白激酶B(AKT)/糖原合酶激酶(GSK)/雷帕霉素靶蛋白(MTOR)相关通路蛋白的表达水平。结果和对照组相比,和枢消积方各组可使HepG2细胞活性、增殖率显著降低(P<0.05);同时可上调BAX的蛋白表达,下调BCL-2及磷酸(p)-AKT、p-GSK、p-MTOR及NS5ATP13的表达(P<0.05),呈浓度依赖性。结论和枢消积方可以抑制HepG2细胞的增殖并诱导凋亡,这可能与和枢消积方抑制NS5ATP13的表达,继而抑制AKT/GSK/MTOR信号转导通路的活化有关。

Effect of Calmodulin and Voltage-dependent Ca^(2+) Channel on the Proliferation of Heptoma Cells Induced by Epidermal Growth Factor

The effect of thyrosine kinase, calmodulin and voltage-dependent Ca 2+ channel on the proliferation of hepatoma cells induced by EGF was studied. Hepatoma cell line SMMC7721 was cultured in RPMI1640 serum-free medium. DNA synthesis rate of hepatoma cells was measured by 3H-TdR incorporation. 10 -9 mol/L EGF could significantly stimulate the proliferation of hepatoma cells (P<0.05), and this effect might be significantly inhibited by tyrosine kinase inhibitor (P<0.001). Calmodulin inhibitor W-7 had no effect on the basic phase of cultured hepatoma cells (P> 0.05), but it had very significantly inhibitory effect on the proliferation of hepatoma cells induced by EGF (P<0.001). Voltage-dependent Ca 2+ channel inhibitor Varapamil had no inhibition on the proliferation of hepatoma cells induced by EGF (P>0.05). It had no effect on the basic phase of cultured hepatoma cells (P>0.05). It is suggested that tyrosine kinase and Ca 2+-calmodulin-dependent pathway may play a critical role on the proliferation of heptoma cells induced by EGF, and voltage-dependent Ca 2+ channel is independent of the effect of EGF.

阿可拉定长循环脂质体的制备与药效学评价

目的制备阿可拉定长循环脂质体(icaritin PEGylated liposomes,Ica-Lips),并评价其对人源肝癌细胞(hepaloblasloma G2,HepG2)的体内抗肿瘤效果。方法采用冷冻干燥-水化法制备Ica-Lips,并在透射电镜下观察Ica-Lips的微观形态,测定Ica-Lips的包封率、粒径分布、Zeta电位,以及在pH7.4磷酸盐缓冲液(PBS)以及大鼠血浆中的药物释放特性;并考察了Ica-Lips的稳定性;比较了Ica-Lips与Ica原料药在大鼠体内的药动学行为,评价Ica-Lips对小鼠接种人源肝癌细胞(HepG2)的抑瘤效果。结果制备的Ica-Lips呈类球状分布,其包封率为96.4%±0.3%,平均粒径为(108.4±3.6)nm,Zeta电位为(-12.9±0.2)mV;与Ica-Lips在pH7.4 PBS中的释药速率相比,其在大鼠血浆中的释药速率明显加快;Ica-Lips在低温条件下保存3个月,稳定性良好;药动学研究表明,Ica-Lips可显著延长药物在大鼠体内的滞留时间,增加药物的生物利用度;药效学研究表明,Ica-Lips对小鼠接种人源肝癌细胞(HepG2)的抑瘤效果显著高于Ica溶液(P<0.05)。结论将阿可拉定制备成长循环脂质体,提高了抗肿瘤效果,具有潜在的临床应用价值。

茶黄素(TF_(1))对人肝癌Bel-7402细胞的抑制作用及机制研究

探究茶黄素(TF_(1))对人肝癌Bel-7402细胞的影响,并阐明其作用机制。通过CCK-8检测细胞活力,用平板克隆形成试验检测细胞增殖能力,细胞划痕愈合试验和Transwell小室法检测细胞迁移,用流式细胞术检测细胞凋亡,Western blot检测细胞凋亡相关蛋白(Bax、Bcl-2、PARP)、迁移相关蛋白(E-cad、N-cad、Vimentin、MMP9)和信号通路相关蛋白(TGF-β、smad3、p-smad3)表达水平。结果表明,不同剂量TF_(1)均可抑制Bel-7402细胞的增殖和迁移,促进其凋亡,并且存在剂量依赖性,剂量越大,抑制作用越强(P<0.05)。与对照组相比,试验组Bax、E-cad蛋白表达水平较高,Bcl-2、PARP,N-cad、Vimentin、MMP9、TGF-β、smad3、p-smad3表达水平较低(P<0.05)。茶黄素可能通过TGF-β信号通路抑制肝癌Bel-7402细胞的增殖、迁移,且促进其凋亡。

siRNA沉默水通道蛋白5基因抑制人肝癌细胞的生长作用

目的通过采用小干扰RNA(siRNA)靶向作用人肝癌细胞Bel-7402中的水通道蛋白5(AQP5)基因,观察其对Bel-7402的增殖及凋亡的作用。方法体外孵育Bel-7402,采用阴性对照siRNA(siRNA-NC)、siRNA-AQP5#1、siRNA-AQP5#2转染细胞。实验设置细胞为对照组、siRNA-NC组、sliRNA-AQP5#1组、siRNA-AQP5#2组。噻唑蓝染色检测细胞的增殖能力;流式细胞技术测定细胞的凋亡情况;蛋白免疫印迹技术和Real time-PCR测量细胞中AQP5蛋白和mRNA的含量。结果siRNA-NC组与对照组相比,细胞的增殖、凋亡及AQP5蛋白和mRNA的含量无明显差异(P>0.05)。与对照组相比,siRNA-AQP5#1组、siRNA-AQP5#2组的细胞的增殖力降低、凋亡率升高、AQP5蛋白和mRNA的含量均降低(均P<0.05)。结论siRNA靶向作用人肝癌细胞AQP5基因通过降低其增殖和升高其凋亡率达到抑制癌细胞的生长作用。

阿霉素对热处理的人肝癌细胞-7721/Adm耐药株细胞毒性的影响

目的： 探讨比较阿霉素（ ADM）与 43℃加热单独或合并处理人肝癌细胞 7721敏感株（简称 7721细胞）和人肝癌细胞 7721/Adm耐药株（简称 7721/Adm细胞）的细胞毒作用。方法：以体外培养的人肝癌细胞 7721敏感株和已经建立的人肝癌细胞 7721/Adm耐药株为研究对象，采用水浴加温法 ,体外细胞毒试验（ MTT法） ,观察 ADM与加热处理对细胞生长抑制的影响；采用流式细胞技术检测热处理对 7721细胞和 7721/Adm细胞胞内阿霉素浓度的影响。结果： (1)热处理可以明显提高两种细胞对阿霉素的敏感性： 7721细胞、 7721/Adm细胞经阿霉素及 43.5℃热处理，其细胞存活率分别下降 35.2％（ 30 min）、 24.8％（ 60 min）和 29.4％（ 30 min）、 22.8％（ 60 min）； (2)流式细胞仪检测显示，热处理可明显提高这两种细胞尤其是 7721/Adm细胞内的阿霉素浓度： 7721细胞组提高 30.8％， HCC 7721/Adm组提高 51％。结论：热处理可以显著提高人肝癌细胞 7721敏感株和人肝癌细胞 7721/Adm耐药株对阿霉素的敏感性。