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.

SUMO-1 Enhancing the p53-induced HepG2 Cell Apoptosis

In order to investigate the effect of small ubiquitin-like modifier-1 (SUMO-1) on the p53-induced HepG2 cell apoptosis, HepG2 cells were transfected by recombinant plasmids as pwtp53, pMDM2 and pSUMO-1 respectively. Western blot was employed to detect the protein expression of the transfected recombinant plasmids and the rate of apoptosis was measured by flow cytometry. The results showed that in cells transfected with pwtp53 and pwtp53+pSUMO-1, the apoptosis rate was (16.79±1.62) % and (18.15±1.36) % respectively, while transfected with pwtp53+pMDM2, the rate was decreased to (5.17±1.23) %. The apoptosis rate was (14.06±1.84) % in the cells transfected with pwtp53+pMDM2+pSUMO-1, significantly higher than that in the cells Transfected with pwtp53+pMDM2 (P<0.01). The apoptosis rates in the cells were all less than 2 % and had no significant difference among the groups. It was suggested that in the HepG2 cells, SUMO-1 can increase the apoptosis induced by wild-type p53 through binding to p53 protein, post-translational modification and inhibiting the p53 degradation by MDM2.

siRNA of ADAM17 gene induces apoptosis,proliferation inhibition and enhances the effects of genistein on HepG2 cells

Objective：To investigate the effects of siRNA of ADAM17 gene and genistein on apoptosis and the inhibition of proliferation in HepG2 cells in an attempt to seek an effective therapy for hepatocellular carinoma. Methods：Cells were divided into control groups and experimental groups and siRNA was used to silence the ADAM17 gene, alone and in combination with genistein. Cells were harvested at several time periods and assessed for proliferation and apoptosis. Proliferation was assayed by MTT at 24, 48, 72 and 96 hours following treatment and apoptosis was assessed by flow cytometric analysis at 48 hours. Results：In siRNA groups, proliferation of cells was significantly inhibited compared to the control groups at 24, 48 and 72 hours（P 〈 0.05）, and apoptosis was significantly increased at 48 hours（P〈 0.01）; In genistein groups, proliferation was inhibited at 24, 48, 72 and 96 hours, and the apoptosis ratio was significantly increased at 48 hours（P〈 0.01）; while in the groups that received the combination of siRNA transfection and genistein treatment, there was a further significant decrease of proliferation and increase in apoptosis compared with either treatment alone. Conclusion：The ADAM17 gene could be an effective target, and genistein could be a useful agent, in the treatment of hepatocellular carcinoma, siRNA of ADAM17 gene and genistein both inhibited HepG2 cells proliferation and promoted apoptosis, and further, the combination of these treatments had a greater effect than either treatment alone.

Hepatocellular carcinoma HepG2 cell apoptosis and caspase-8 and Bcl-2 expression induced by injectable seed extract of Coix lacryma-jobi

BACKGROUND:Many Chinese herbs,especially herbal injections,have been shown to have anti-tumor effects in recent years.However,since most reports focus on the clinical effectiveness of these herbs,their mechanisms of action are not well understood.In this study,we assessed apoptosis in the hepatocellular carcinoma (HCC) cell line HepG2 induced by an injectable extract from the seed of Coix lacryma-jobi (Semen coicis,SC),and monitored the expression of Bcl-2 and caspase-8.METHODS:Injectable SC was applied to HepG2 cells at different concentrations and the cells were collected 12,24 and 48 hours later.5-fluorouracil was used as a positive control group,and fluorescence-activated cell-sorting cytometry was used to measure the apoptosis rate of HepG2 cells and the expression of Bcl-2 and caspase-8 proteins.RESULTS:SC induced apoptosis in HepG2 cells in a concentration and time-dependent manner,and the expression of caspase-8 was elevated and prolonged.However,it did not significantly influence the expression of Bcl-2.CONCLUSION:Injectable SC may induce apoptosis in HCC cells by regulating the expression of caspase-8.

Partial Beclin 1 silencing aggravates doxorubicin-and Fasinduced apoptosis in HepG2 cells

AIM： To investigate the role of Beclin 1 on the susceptibility of HepG2 cells to undergo apoptosis after anti-Fas antibody or doxorubicin treatment. METHODS： Beclin 1 silencing was achieved using RNA interference. DNA ploidy, the percentage of apoptotic cells and the mitochondrial membrane potential were assessed by flow cytometry. Levels of Beclin 1, BCI-XL and cytochrome c, and the cleavage of poly （ADP-ribose） polymerase （PARP） were assayed by using Western blots. RESULTS： Beclin 1 expression decreased by 75% 72 h after Beclin 1 siRNA transfection. Partial Beclin 1 silencing significantly increased the percentage of subG1 cells 24 and 40 h after treatment with doxorubicin or anti-Fas antibody, respectively, and this potentiation was abrogated by treatment with a pan-caspase inhibitor. Partial Beclin 1 silencing also increased PARP cleavage, mitochondrial membrane depolarization and cytosolic cytochrome c. The pro-apoptotic consequences of partial Beclin 1 silencing were not associated with a decline in Bcl-XL expression.CONCLUSION： Partial Beclin 1 silencing aggravates mitochondrial permeabilization and apoptosis in HepG2 cells treated with an anti-Fas antibody or with doxorubicin.

HBx activates FasL and mediates HepG2 cell apoptosis through MLK3-MKK7-JNKs signal module

AIM： To investigate the possible mechanism by which hepatitis B virus X protein （HBx） mediates apoptosis of HepG2 cells. METHODS： HBx expression vector pcDNA3.1-X was transfected into HepG2 cells to establish an HBx high- expression cellular model as pcDNA3.1-X transfected group. The pcDNA3.1-X and pSilencer3.1-shHBX （HBx antagonist） were cotransfected into HepG2 cells to es- tablish an HBx low-expression model as RNAi group. Untransfected HepG2 cells and HepG2 cells transfected with negative control plasmid were used as controls. Apoptosis rate, the expression of Fas/FasL signaling pathway-related proteins and the phosphorylation lev- els of MLK3, MKK7 and JNKs, which are upstream molecules of death receptor pathways and belong to the family of mitogen-activated protein kinases （MAPKs）,were measured in each group RESULTS： Compared with HepG2 cell group and RNAi group, apoptosis rate, the expression of Fas and FasL proteins, and the activation of MLK3, MKK7 and 3NKs were increased in the pcDNA3.1-X transfected group. The activation of JNKs and expression of FasL protein were inhibited in the pcDNA3.1-X transfected group when treated with a known JNK inhibitor, SP600125. When authors treated pcDNA3.1-X transfected group with K252a, a known MLK3 inhibitor, the activation of MLK3, MKK7 and 3NKs as well as expression of FasL protein was inhibited. Furthermore, cell apoptosis rate was also significantly declined in the presence of K252a in the pcDNA3.1-X transfected group. CONCLUSION： HBx can induce HepG2 cell apoptosis via a novel active MLK3-MKK7-JNKs signaling module to upregulate FasL protein expression.

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.

mRNA transcriptome profiling of human hepatocellular carcinoma cells HepG2 treated with Catharanthus roseus-silver nanoparticles

BACKGROUND The demand for the development of cancer nanomedicine has increased due to its great therapeutic value that can overcome the limitations of conventional cancer therapy.However,the presence of various bioactive compounds in crude plant extracts used for the synthesis of silver nanoparticles(AgNPs)makes its precise mechanisms of action unclear.AIM To assessed the mRNA transcriptome profiling of human HepG2 cells exposed to Catharanthus roseus G.Don(C.roseus)-AgNPs.METHODS The proliferative activity of hepatocellular carcinoma(HepG2)and normal human liver(THLE3)cells treated with C.roseusAgNPs were measured using MTT assay.The RNA samples were extracted and sequenced using BGIseq500 platform.This is followed by data filtering,mapping,gene expression analysis,differentially expression genes analysis,Gene Ontology analysis,and pathway analysis.RESULTS The mean IC 50 values of C.roseusAgNPs on HepG2 was 4.38±1.59μg/mL while on THLE3 cells was 800±1.55μg/mL.Transcriptome profiling revealed an alteration of 296 genes.C.roseusAgNPs induced the expression of stress-associated genes such as MT,HSP and HMOX-1.Cellular signalling pathways were potentially activated through MAPK,TNF and TGF pathways that are responsible for apoptosis and cell cycle arrest.The alteration of ARF6,EHD2,FGFR3,RhoA,EEA1,VPS28,VPS25,and TSG101 indicated the uptake of C.roseus-AgNPs via both clathrin-dependent and clathrinindependent endocytosis.CONCLUSION This study provides new insights into gene expression study of biosynthesised AgNPs on cancer cells.The cytotoxicity effect is mediated by the aberrant gene alteration,and more interestingly the unique selective antiproliferative properties indicate the C.roseusAgNPs as an ideal anticancer candidate.

Cytotoxic effect of oxaloacetate on a human hepatic carcinoma cell line HepG2 through apoptosis and ROS accumulation

Aim Oxaloacetate （OA） is one of the intermediates in the Krebs cycle. In addition to its role in the metabolism of energy production, OA may have other effects on the cell. We report in the present study that OA could have a cell type dependent cytoto^ic effect on the human hepatic carcinoma cell line HepG2 through induction of apoptosis and ROS accumulation. In our study, OA decreased the viability and colony formation of HepG2 cell and induced cell death. Caspase-3 activity was increased, pro-apoptotic protein Bax was up-regulated, and anti-ap- optotic protein Bcl-2 was clown-regulated in OA-treated HepG2 cells indicating that apoptosis through the intrinsic pathway was involved in the death of the cell. The level of reactive oxygen species （ROS） in OA-treated HepG2 cells was increased. Anti-oxidant N-acetylcysteine （NAC） and glutathione （GSH） prevented the viability of the cell induced by OA from decrease but could not alleviate the enhanced level of apoptotic Bax/Bcl-2 mRNA expres- sion ratio, which suggests that the OA-induced apoptosis of HepG2 cell is not driven by oxidative damage and at least two distinct mechanisms, one mediated by ROS and one involving apoptosis, lead to the cytotoxic effect of OA on HepG2 cells. These studies expand the biological functional repertoire of OA and provide a mechanism by which hepatocellular carcinoma may be targeted by OA to kill the cancer cells.

Apoptosis-inducing effects of extracts from desert plants in HepG2 human hepatocarcinoma cells

Objective:To investigat the mechanism of antitumor efficacy of Origanum clayi(O.clayi) and Ochradenus baccatus(O.baccatus) extracts by exploring apoptosis-inducing potential.Methods:The aqueous extracts of aerial parts of aforementioned plants were prepared and used for this study.HepG2 cells were treated with varying concentrations(0,2 and 5 mg/mL)of each plant extract for 24 or 48 h.Cell apoptosis was measured by annexin V-fluorescein isothiocyanate binding assay and flow cytometry.The expression levels of various apoptosisrelated genes were determined by semi-quantitative reverse transcription-polymerase chain reaction.Results:O.clayi and O.baccatus extracts exerted apoptotic effects on HepG2 cells for 48 h following treatment.O.clayi extract was found to be a better apoptosis-inducing agent than O.baccatus extract as the former delivered greater efficacy at a lower concentration.Both extracts manifested upregulation of Bax,Bad.cytochrome c.caspase-3,caspase-7.caspase-9 and poly(adenosine diphosphate-ribose) polymerase.Conclusions:The aqueous extracts of O.clayi and O.baccatus are capable of inducing apoptosis in HepG2 cells through modulation of mitochondrial pathway which explains their antitumor activities.These desert plants may serve as useful resources to develop effective remedies for hepatocellular carcinoma and other human malignancies.

5-Demethylnobiletin and its major metabolites:efficient preparation and mechanism of their anti-proliferation activity in HepG2 cells

5-Demethylnobile tin(5-DMN),a hydroxylated polymethoxyflavone(OH-PMF)identified in aged citrus peels,has demonstrated health benefiting effects in previous studies.5-DMN undergoes biotransformation in vivo,yielding 5,3’-didemethylnobiletin(5,3’-DDMN),5,4’-didemethylnobiletin(5,4’-DDMN)and5,3’,4’-tridemethylnobiletin(5,3’,4’-TDMN).However,the anti-cancer effects of 5-DMN and its in vivo metabolites against HepG2 cells remain unclear.In this study,an efficient chemical synthetic method was developed to obtain 5-DMN and its 3 metabolites,and their molecular structures were confirmed by;H NMR and LC-MS.Cytotoxicity,cell cycle arrestment,apoptosis and caspase-3 expression were investigated to evaluate the anti-liver cancer effects of these OH-PMFs on HepG2 cells.The results showed that all 4 compounds inhibited the proliferation of HepG2 cells in a concentration-dependent manner.Their anti-proliferative activity was exerted through inducing G2/M phase arrestment,cell apoptosis and promoting expression of a key apoptotic protein called cleaved caspase-3.Our results indicated that 5,3’-DDMN and5,3’,4’-TDMN showed a stronger inhibitory activity on cell proliferation than 5-DMN,followed by 5,4’-DDMN.The expression of cleaved caspase-3 was the highest in cells treated with 5,4’-DDMN,implying that the apoptosis induced by other OH-PMFs might be mediated by other apoptotic execution proteins.Our research reveals the application potential and scientific evidence for the production and functionality of OH-PMFs.

Brucea javanica oil inhibits proliferation of hepatocellular carcinoma cells and induces apoptosis via the PI3K/AKT pathway

Background:Brucea javanica oil(BJO),distributed primarily in Southeast Asia,has long been utilized as a therapeutic agent for treating malignancies.However,its anticancer mechanisms are not clearly understood.The objective of this study was to examine the mechanisms underlying its treatment of hepatocellular carcinoma cells.Methods:CCK8 assay was used to evaluate cell viability.Hoechst33342 staining and flow cytometry analyses were used to examine apoptosis.Mito-Tracker Red CMXRos kit was used to measure the membrane potential of mitochondria.ATP assay kit was used to evaluate ATP levels.Western blots were used to assess the presence of AKT,adenosine monophosphate-activated protein kinase,Caspase3,Caspase9,Bax,and Bcl-2.Results:BJO inhibited the proliferation of hepatocellular carcinoma cells HepG2 in a time-and dose-dependent manner.It induced apoptosis,with the percentage of cells treated with 50–150μg/mL BJO increasing from 8.01%to 28.02%in a concentration-dependent manner(P<0.05,when 50μg/mL of BJO group compared with the control group;P<0.001,when 100 or 150μg/mL of BJO group compared with the control group).After exposed to BJO,the expression of C-caspase3,C-caspase9 and Bax upregulated while that of Bcl-2 downregulated.BJO suppressed the PI3K/AKT pathway and promoted phosphorylation of adenosine monophosphate-activated protein kinase,while repressing the phosphorylation of mechanistic target of rapamycin.Compared with treatment by BJO alone,the PI3K/AKT agonist 740Y-P increased the survival rate of HepG2 cells(P<0.01)and attenuated the inhibitory effect of BJO on cell apoptosis(P<0.05).Conclusion:BJO is capable of inhibiting proliferation of HepG2 cells and inducing apoptosis via the PI3K/AKT pathway.

Inhibitory effect of metformin on the proliferation of human hepatoma HepG2 cells and its potential mechanism

Objective： This work aimed to study the inhibitory effect and the related mechanism of metformin （MET） on the proliferation of human hepatoma HepG2 cells. Methods： Human hepatoma HepG2 cells were treated with MET （0, 2, 10, and 50 mM）. The inhibitory effect of MET on the proliferation of HepG2 cells was determined by MTT method. The apoptosis of HepG2 cells was detected by flow cytornetry. The expression of cyclin D1 in HepG2 cells was examined by Western blot. ROS-DHE fluorescence probe was used to stain the reactive oxygen species （ROS） generated by HepG2 cells after treat- ment. Results： MET could inhibit the proliferation of HepG2 cells in a dose and time dependent manner. MET promoted the apoptosis of HepG2 cells. In addition, MET suppressed the expression of cell cycle protein cyclin D1 and induced the produc- tion of ROS in HepG2 cells. Conclusion： MET can inhibit the proliferation of human hepatoma HepG2 cells and induce cell apoptosis. Meanwhile, MET has the ability to decrease the expression of cyclin D1 and induce ROS generation, which may be involved in the mechanism of inhibiting hepatoma cells proliferation.

Stevenleaf from Gynostemma Pentaphyllum inhibits human hepatoma cell(HepG2)through cell cycle arrest and apoptotic induction

The anticancer activity of stevenleaf(SV)on the basis of cell viability,cell cycle,and apoptosis induction in HepG2 cancer cells were evaluated.SV controlled the growth of HepG2 cells with IC50 of 139.82μmol/L for 24 h,IC50 of 119.12μmol/L for 48 h and cell cycle arrested at G0/G1 phase,induced cell apoptosis and enhanced intracellular ROS generation.For cell cycle arrest,the mRNA expression levels of p21,p27 and p53 were up-regulated,while the expression levels of Cyclin A,Cyclin D1,Cyclin E and CDK1/2 were downregulated.SV efficiently up-regulated TNF R1,TRADD1 and FADD and down-regulated Caspase8 for cell death receptors;similarly,up-regulated Bax,Bak,Cytc,Apaf1,Caspase3 and Caspase9,and down-regulated Bcl2,Bcl xl and Bad for mitochondrial signal pathway.SV induced the mTOR-mediated cell apoptosis in HepG2 cells via activation of Akt and AMPK.The mechanistic explanation for the anticancer activity of SV as functional food can be derived from above results.

Autophagy in anti-apoptotic effect of augmenter of liver regeneration in HepG2 cells

AIM:To investigate the role of autophagy in the antiapoptotic effect of augmenter of liver regeneration(ALR).METHODS:Autophagy was induced through serum deprivation.An ALR-expressing plasmid was transfected into HepG2 cells,and autophagic flux was determined using fluorescence microscopy,electron microscopy,Western blot and quantitative polymerase chain reaction(q PCR) assays.After ALR-expressing plasmid transfection,an autophagy inhibitor [3-methyladenine(3-MA)] was added to HepG2 cells,and apoptosis was observed using fluorescence microscopy and flow cytometry.RESULTS:Autophagy was activated in HepG2 cells,peaking at 24 h after serum deprivation.Microtubuleassociated protein light chain three-II levels were higher in HepG2 cells treated with ALR than in control cells,fluorescence microscopy,electron microscopy and q PCR studies showed the similar trend,and p62 levels showed the opposite trend,which indicated that ALR may play an important role in increasing autophagy flux.The numbers of apoptotic cells were substantially higher in HepG2 cells treated with both ALR and 3-MA than in cells treated with ALR alone.Therefore,the protective effect of ALR was significantly attenuated or abolished when autophagy was inhibited,indicating that the anti-apoptotic effect of ALR may be related to autophagy.CONCLUSION:ALR protects cells from apoptosis partly through increased autophagy in HepG2 cells and may be valuable as a new therapeutic treatment for liver disease.

Calcium chloride linked camel milk derived casein nanoparticles for the delivery of sorafenib in hepatocarcinoma cells

Sorafenib,a multikinase inhibitor used for the treatment of hepatocellular carcinoma,is limited by its low oral bioavailability.To overcome this drawback,we have developed novel camel milk casein-derived nanoparticles as a drug delivery system.Camel milk casein is not only biocompatible on oral administration but is actually a dietary protein of pharmaceutical relevance.Casein is used because of its amphiphilic nature,self-assembling property,ability to show sustained release,and capability of encapsulating both hydrophilic and hydrophobic drugs.In this study,camel milk casein nanoparticles loaded with sorafenib were developed and characterized.Characterization of casein nanoparticles was done by dynamic light scattering(DLS),zeta potential analysis,scanning light microscopy(SEM),and FTIR.The drug content in nanoparticle and drug-protein binding studies were conducted by UV spectroscopy.The cytotoxicity and cellular uptake efficiency studies were performed in HepG2 cell lines.It was observed that the cytotoxic effect of sorafenib loaded camel milk casein nanoparticles was more than free sorafenib in HepG2 cells.This work suggests camel milk casein as a suitable drug delivery molecule for sorafenib.In the future,it may also be used in enhancing the efficacy and specific distribution of other water-insoluble anticancer drugs.

Apoptosis Induced by N-Nitrosamines in Two Cancer Cell Lines

In the present study, we investigated the induction of apoptosis by N-nitrosopyrrolidine (NPYR) and N-nitrosodimethy-lamine (NDMA) in two human cell lines: HL-60 (leukemia) and HepG2 (hepatoma). Apoptotic cells were identified by: 1) chromatin condensation, 2) flow cytometry analysis and 3) poly (ADP-ribose) polymerase cleavage. Both cell lines exhibited morphological changes consistent with apoptotic events following treatment with N-nitrosamines. Flow cytometry analysis showed that both N-nitrosamines induced apoptotic cell death in a concentration and time dependent- manner. NPYR was stronger than NDMA, since it induced a significant apoptotic cell death after 72 h starting from a concentration of 10 mM, whereas NDMA was effective at 27 mM. Furthermore, NPYR and NDMA caused the cleavage of PARP in HL-60 cells whereas no PARP cleavage was detected in HepG2 cells. However, NPYR- and NDMA-induced cell death in HepG2 cells was prevented by specific caspase inhibitors. Caspase-8 mediated main pathway and was responsible for 76% (NPYR) and 64% (NDMA) inhibition of apoptosis. The data demonstrate that NPYR and NDMA induce apoptosis in HL-60 and HepG2 cell lines via caspase-dependent pathway.

Initial study on apoptosis in HepG-2 Human heptocarcinoma cell line by CSS

Objective To discuss on mechanism of the killing and apoptosis inducing effect induced by total alkaloid in the CSS(Capparis spinosa L.saponin,CSS)on human hepatocarcinoma cell Line HepG-2.Methods The killing effect of the CSS on human hepatocarcinoma cell Line HepG-2 was observed by MTT method.Morphological observation of the HepG-2 cells was completed by fluorescence microscope.This test was signed to observe the changes of the cell cycle of HepG-2 cells affected by the CSS by PI single-staining,and to observe if there were typical apoptosis peaks.The apoptosis inducing effect and changing of mitochondria membrane potential of the CSS on the HepG-2 cells were studied by flow cytometry.The effect of intracellular Ca2+ level of CSS on the HepG-2 cells was measured by laser confocal microscope.Results CSS has growth inhibiting on the HepG-2 and seems to be enhanced with the increasing concentration of CSS,and its IC50 value was 46.16 μg·mL-1.The HepG-2 cells are characteristic apoptosis morphologic changed,and the apoptosis percentage is increased to 66.652% in the 50 μg·mL-1 dosage group.The cells cycle has been changed obviously that the progresses of cells cycle of G1 period and G2 period in high dosage group have been blocked,and the cellular proportion in G2 period is decreased by the function of CSS for 24 h.The mitochondria membrane potential of HepG-2 cells induced by CSS is decreased in various degrees.In addition,the intracellular Ca2+ level is increased by the function of CSS in the middle and high dose groups.Conclusions The CSS has obviously killing and apoptosis inducing effect on human hepatocarcinoma cell Line HepG-2 by the mechanism of decreasing the mitochondria membrane potential and increasing the intracellular Ca2+ level.

黄连素通过提高活性氧水平促进HepG2细胞凋亡

本研究用SRB法、流式细胞术和荧光显微技术等方法检测分析了黄连素对人肝癌细胞株HepG-2的毒性并探究了其作用机制.结果显示,黄连素的毒性作用呈时间-剂量依赖效应,24h和48h的IC50值分别为44.10μmol·L^(-1)和8.53μmol·L^(-1);160μmol·L^(-1)时黄连素具有致死效应;当加入抗氧化剂NAC,黄莲素抑制和致死作用明显减弱.黄连素可引起HepG-2细胞凋亡,NAC作用后细胞凋亡率降低;黄连素可使胞内ROS含量持续升高;同时在黄连素作用下还降低了细胞内抗氧化剂GSH含量.表明黄连素可以通过提高细胞内ROS,耗竭胞内抗氧化剂进而诱导肝癌细胞凋亡.

人参皂苷Rh4诱导肝癌细胞HepG2的凋亡及分子机制

目的:探讨人参皂苷Rh4对人肝癌HepG2细胞凋亡的作用及机制。方法:采用MTT比色法测定不同浓度(10、20和40μmol/L)人参皂苷Rh4对人肝癌HepG2细胞活力的抑制作用;用流式细胞术检测定细胞凋亡率;通过Hoechst 33258和TUNEL染色观察人参皂苷Rh4诱导人肝癌HepG2细胞凋亡的形态学变化;Western blot法检测凋亡相关蛋白Bax、Bcl-2、caspase-3和caspase-9的表达情况。结果:人参皂苷Rh4能够明显促进人肝癌HepG2细胞的凋亡,且呈剂量依赖性;TUNEL和Hoechst 33258染色实验结果表明,人参皂苷Rh4作用24 h后,细胞呈现明显皱缩、肿胀、破裂等凋亡形态;Western blot分析结果表明,随着人参皂苷Rh4给药浓度的增加,抗凋亡蛋白Bcl-2表达量逐渐下降,而促凋亡蛋白Bax、cleaved caspase-3和caspase-9的表达逐渐升高。结论:人参皂苷Rh4可诱导人肝癌HepG2细胞凋亡,其作用机制可能与下调Bcl-2以及上调Bax、cleaved caspase-3和caspase-9蛋白表达有关。