Inhibitory Effect of Sesquiterpenoid M36 from Myrrha on Growth of Human Hepatoma Cells / 中国实验方剂学杂志

ObjectiveThe antitumor activity of sesquiterpenoid M36 isolated from Myrrha against human hepatoma HepG2 cells was investigated in this study. MethodHepG2 cells were treated with M36 at different concentrations （0， 2， 4， 6， 8， 10 μmol·L-1）. Firstly， the effects of M36 on the proliferation of human hepatoma HepG2 cells were detected by methyl thiazolyl tetrazolium （MTT）， colony formation assay， and EdU proliferation assay. Hoechst staining， flow cytometry analysis， and Western blot were used to explore the effect of M36 on the apoptosis of human hepatoma HepG2 cells. Acridine orange staining and western blotting were used to examine the effect of M36 on autophagy in HepG2 cells. Finally， Western blot was used to detect protein expression of cancer-related signaling pathways. ResultCompared with the blank group， M36 treatment significantly inhibited the proliferation of human hepatoma HepG2 cells （P<0.01）， and the half inhibitory concentration （IC50） value of M36 for 48 h was 5.03 μmol·L-1， in a dose- and time-dependent manner. M36 was also able to induce apoptosis and autophagy in human hepatoma HepG2 cells. After treatment with 8 μmol·L-1 M36 for 48 hours， the apoptosis rate of HepG2 cells was （42.03±9.65）% （P<0.01）. Compared with the blank group， HepG2 cells treated with 4 and 8 μmol·L-1 M36 for 48 h had a significant increase in cleaved poly ADP-ribose polymerase （cleaved-PARP） protein levels （P<0.01）. Acridine orange staining showed that autophagy was significantly activated in HepG2 cells treated with 4 and 8 μmol·L-1 M36 for 48 h compared with the blank group （P<0.01）， which was further verified by the up-regulation of microtubule-associated protein 1 light chain 3 Ⅱ （LC3 Ⅱ）. Western blot results showed that compared with the blank group， the levels of phosphorylated extracellular regulated protein kinase （p-ERK）， phosphorylated p38 mitogen-activated protein kinase （p-p38 MAPK）， phosphorylated c-Jun N-terminal kinase （p-JNK）， and its downstream nuclear transcription factors c-Jun and p-c-Jun protein were significantly increased in M36 group （P<0.05， P<0.01）. The mechanism may be related to the up-regulation of MAPK signaling pathway. ConclusionThe sesquiterpenoid M36 isolated from Myrrha inhibits the proliferation of human hepatoma HepG2 cells and promotes apoptosis and autophagy， which may be related to the activation of the MAPK signaling pathway.

Mulberry Leaf Polyphenol Extract and Rutin Induces Autophagy Regulated by p53 in Human Hepatoma HepG2 Cells.

The edible leaves of the mulberry (Morus alba L.) plant are used worldwide. They contain abundant polyphenolic compounds with strong anticancer properties. We previously revealed that apoptosis was mediated in p53-negative Hep3B cells, and mulberry leaf polyphenol extract (MLPE) induced autophagy in p53-transfected Hep3B cells. However, how this autophagy is induced by p53 in human hepatoma HepG2 (p53 wild type) cells remains unclear. In the current study, MLPE induced autophagy, as demonstrated by enhanced acidic vesicular organelle staining, by upregulating beclin-1, increasing LC3-II conversion, and phosphorylating AMPK. In HepG2 cells, these processes were associated with p53. Western blot also revealed phosphatidylinositol-3 kinase (PI3K), p-AKT, and fatty acid synthase (FASN) suppression in MLPE-treated cells. Moreover, treatment with the p53 inhibitor pifithrin-α (PFT-α) inhibited autophagy and increased apoptotic response in MLPE-treated HepG2 cells. PFT-α treatment also reversed MLPE-induced PI3K, p-AKT, and FASN suppression. Thus, co-treatment with MLPE and PFT-α significantly increased caspase-3, caspase-8, and cytochrome c release, indicating that p53 deficiency caused the apoptosis. In addition, rutin, a bioactive polyphenol in MLPE, may affect autophagy in HepG2 cells. This study demonstrates that MLPE is a potential anticancer agent targeting autophagy and apoptosis in cells with p53 status. Moreover, this work provides insight into the mechanism of p53 action in MLPE-induced cytotoxicity in hepatocellular carcinoma.

The positive feedback loop between Nrf2 and phosphogluconate dehydrogenase stimulates proliferation and clonogenicity of human hepatoma cells.

Recent studies report that nuclear factor-erythroid-2-related factor 2 (Nrf2) facilitates tumor progression through metabolic reprogramming in cancer cells. However, the molecular mechanism underlying the oncogenic functions of Nrf2 is not yet well understood. Some of the pentose phosphate pathway (PPP) enzymes are considered to play a role in the cancer progression. The present study was intended to explore the potential role of phosphogluconate dehydrogenase (PGD), one of the PPP enzymes, in the proliferation and migration of human hepatoma HepG2 cells. Genetic ablation of Nrf2 attenuated the expression of PGD at both transcriptional and translational levels. Notably, Nrf2 regulates the transcription of PGD through direct binding to the antioxidant response element in its promoter region. Nrf2 overexpression in HepG2 cells led to increased proliferation, survival, and migration, and these events were suppressed by silencing PGD. Interestingly, knockdown of the gene encoding this enzyme not only attenuated the proliferation and clonogenicity of HepG2 cells but also downregulated the expression of Nrf2. Thus, there seems to exist a positive feedback loop between Nrf2 and PGD which is exploited by hepatoma cells for their proliferation and survival. Treatment of HepG2 cells with ribulose-5-phosphate, a catalytic product of PGD, gave rise to a concentration-dependent upregulation of Nrf2. Collectively, the current study shows that Nrf2 promotes hepatoma cell growth and progression, partly through induction of PGD transcription.

Identification and characterization of cell-bound membrane vesicles.

In contrast to the released/circulating membrane vesicles (extracellular vesicles), cell-bound membrane vesicles are poorly identified and characterized. In this study, cell-bound membrane vesicles on human umbilical vein endothelial cells (HUVECs) and human hepatoma HepG-2 cells were investigated. We identified that cell-bound membrane vesicles are not co-localized with the major markers for extracellular vesicles (e.g. phosphatidylserine, CD63, CD107α, CD31, and DNA fragments for the three well-known types of extracellular vesicles) and for intracellular organelles with similar sizes (e.g. MitoTracker and LAMP1/LAMP3 for mitochondria and multivesicular bodies or lysosomes, respectively). The data imply that cell-bound membrane vesicles are neither the precursors of extracellular vesicles nor a false structure pushed up by an intracellular organelle but probably a novel unknown structure in the plasma membrane. Moreover, we revealed that cell-bound membrane vesicles are resistant to various detergents including but probably not limited to Triton X-100, SDS, and saponin. We further characterized that these unique vesicles are soluble in organic solvents (e.g. chloroform-methanol mixture and ethanol) which can be prevented by a lipid-stabilizing fixative (e.g. OsO4) and that they are co-localized with, but do not monopolize, the major markers (e.g. caveolin-1 and GM1) for lipid rafts (a nano-sized detergent-resistant domains in the plasma membrane). The data imply that cell-bound membrane vesicles contain the lipid component and lipid rafts. Involvement of other specific unknown components might explain the detergent resistance of cell-bound membrane vesicles. Further research will mainly depend on the establishment of an effective approach for isolation/purification of these vesicles from the plasma membrane.

Study on the Effects and Mechanism of Celastrol on Proliferation and Apoptosis of Human Hepatoma HepG2 Cells in vitro / 中国药房

OBJECTIVE:To study the effects of celastrol on the proliferation and apoptosis of human hepatoma HepG2 cells, and investigate its mechanism. METHODS:CCK-8 method was used to determine the cell activity 24,48,72 h after treated by 2, 5,10 μmol/L celastrol,and the proliferation inhibition rate and half inhibitory concentration(IC50)were calculated;flow cytome-try was conducted to detect the cell apoptosis rate and cycle change 24 h after treated by 2,5,10μmol/L celastrol,and the DMSO was used as negative control;rhodamine 123 staining method was used to determine the mitochondrial membrane potential 48 h af-ter treated by 2,5,10 μmol/L celastrol,and the DMSO was used as negative control;Western blot was adopted to detect the pro-apoptotic related genes Bax and B lymphoma 2(Bcl-2)protein expressions 0,12,24,36 h after treated by 5 μmol/L celastrol. RESULTS:2,5,10 μmol/L celastrol can inhibit cell proliferation,IC50 was 5.834 μmol/L. 2,5,10 μmol/L celastrol can induce apoptosis;5,10 μmol/L celastrol can block cell in G0/G1,S phases,compared with negative control group,with significant differ-ences(P<0.05 or P<0.01),and the above effects all showing certain concentration-dependent manner. 5 μmol/L celastrol can in-crease Bax protein expression and decrease Bcl-2 protein expression after cultured for 12,24,36 h,showing certain time-depen-dent manner;compared with 0 h,there was significant difference(P<0.05 or P<0.01). CONCLUSIONS:Celastrol can obvious-ly inhibit the proliferation of human hepatoma HepG2 cells and induce their apoptosis,and the mechanism may be related with strengthening mitochondrial permeability and promoting the release of apoptosis-inducing factor.

Preparation of TPGS-modified artesunate liposomes and their in vitro anti-tumor activity / 中成药

AIM To prepare D-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-modified artesunate liposomes and to investigate the in vitro anti-tumor activity.METHODS The liposomes prepared by thin-film dispersion method were characterized by transmission electron microscopy and particle size analyzer,and the encapsulation efficiency was determined by ultrafiltration centrifugation.The liposomes' cytotoxicity to human hepatoma HepG2 cells was evaluated by MTT method.RESULTS The average particle size,PDI,Zeta potential,encapsulation efficiency,drug loading of the liposomes were 126.7 nm,0.182,-10.1 mV,78.8％ and 18.38％,respectively.The liposomes displayed a significant inhibition on HepG2 cells with the IC50 value of 0.034 μmol/mL.CONCLUSION Compared with non-TPGS-modified artesunate liposomes,the TPGS-modified artesunate liposomes prepared by this method afford smaller vesicle size,better stability and higher encapsulation efficiency with stronger in vitro anti-tumor activity.

Effect of ultrasound microbubble mediated miRNA delivery on the ability of migration ,invasion and clon-ing of human hepatoma HepG2 cells / 实用医学杂志

Objective To invstigate the effect of ultrasound microbubble mediated miRNA delivery on mi-gration,invasion and cloning ability of human hepatoma HepG2 cells. Methods The migration,invasion and col-ony forming ability of HepG2 cells were measured after transfection with antisense miRNA-21/221 and miRNA-199a mimic via the optimal ultrasound microbubble transfection method. Results Compared with the control group ,the migration ,invasion and cloning ability of cells were significantly inhibited after transfection with miRNA mimics(P < 0.05,respectively),especially for miR-199a(relative cell migration rate was 31.05%,the number of invasive cells were 38.67 ± 4.51 and the number of clones were 105.67 ± 5.86). Conclusion The pres-ent study may provide new ideas and clues for gene therapy and prognosis of hepatocell ular carcinoma through ana-lyzing the effect of miRNAs on the biological characteristics of human hepatoma HepG2 cells.

Influence of different chemical agents (H2O2, t-BHP and MMS) on the activity of antioxidant enzymes in human HepG2 and hamster V79 cells; relationship to cytotoxicity and genotoxicity.

We investigated activities of antioxidant enzymes (AEs), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in human HepG2 and hamster V79 cells treated with a scale of concentrations of hydrogen peroxide (H2O2), tert-butyl hydroperoxide (t-BHP) and methyl methanesulfonate (MMS). Cytotoxicity and genotoxicity of these substances were evaluated simultaneously. We have found out that H2O2, t-BHP and MMS predictably induce significant concentration-dependent increase of DNA lesions in both cell lines. Cytotoxicity detected in V79 cells with help of PE test was in a good conformity with the level of DNA damage. MTT test has proved unsuitable, except for MMS-treated V79 cells. Compared with human cells HepG2, hamster cells V79 manifested approximately similar levels of SOD and CAT but ten times higher activity of GPx. Across all concentrations tested the most significant increase of activity of the enzyme CAT was found in H2O2- and t-BHP-treated HepG2 cells, of the enzyme SOD in t-BHP- and MMS-treated V79 cells, and of the enzyme GPx in H2O2-treated V79 cells. We suggest that stimulation of enzyme activity by the relevant chemical compounds may result from transcriptional or post-transcriptional regulation of the expression of the genes CAT, SOD and GPx. Several authors suggest that moderate levels of toxic reactants can induce increase of AEs activities, while very high levels of reactants can induce their decrease, as a consequence of damage of the molecular machinery required to induce AEs. Based on a great amount of experiments, which were done and described within this paper, we can say that the above mentioned principle does not apply in general. Only the reactions of t-BHP affected HepG2 cells were consistent with this idea.

Metabolism and cytotoxic effects of phosphatidylcholine hydroperoxide in human hepatoma HepG2 cells.

In this study, we investigated cellular uptake and metabolism of phosphatidylcholine hydroperoxide (PCOOH) in human hepatoma HepG2 cells by high performance liquid chromatography-tandem mass spectrometry, and then evaluated whether PCOOH or its metabolites cause pathophysiological effects such as cytotoxicity and apoptosis. Although we found that most PCOOH was reduced to PC hydroxide in HepG2 cells, the remaining PCOOH caused cytotoxic effects that may be mediated through an unusual apoptosis pathway. These results will enhance our fundamental understanding of how PCOOH, which is present in oxidized low density lipoproteins, is involved in the development of atherosclerosis.

Intervention Effects of(E)-4-[2-(4-Chlorophenoxy)-2-Methylpropanoyloxy]-3-Methoxyphenyl Acrylic Acid on Fat Accumulation in Human Hepatoma HepG2 Cells / 中国药房

OBJECTIVE:To investigate the intervention effects of (E)-4-[2-(4-chlorophenoxy)-2-methylpropanoyloxy]-3-me-thoxyphenyl acrylic acid (AZ) on fat accumulation in human hepatoma HepG2 cells. METHODS:Oleic acid was used to induce fat accumulation in HepG2 cells in logarithmic phase for establishing models of fat accumulation,which were divided into a model group,a positive control group(100 μg/ml simvastatin),and the groups of 15.63,31.25,62.5,125,250,500 and 1 000 μg/ml AZ,and a normal control group was set up. MTT method was used to detect the survival rates of all groups of cells,kit was per-formed to determine the contents of triglyceride (TG) in all groups of cells and calculate the clearance rates,and oil red O stain was conducted to observe the lipid droplet morphology of all groups of cells. RESULTS:Compared to the normal control group, the model group and the groups of 15.63-125 μg/ml AZ demonstrated no obviously different survival rate of cells,and the groups of 250-1 000 μg/ml AZ had lower survival rate of cells. There was statistically significance (P<0.05). The contents of TG in the cells of the model group were higher than those in the cells of the normal control group. The positive control group and the groups of 62.5 and 125 μg/ml AZ had lower contents of TG in the cells compared to the model group,showing a TG clearance rate of (28.58 ± 0.15)%,(14.51 ± 0.09)% and (29.72 ± 0.16)% respectively. There was statistically significance (P<0.01 or P<0.05). There were much more lipid droplets in the cells of the model group than in those of the normal control group. The lipid droplets in AZ groups gradually became less in quantity and smaller with the increasing in drug concentration. CONCLUSIONS:AZ has inter-vention effect on fat accumulation in HepG2 cells.

Effects of Salvia officinalis and Thymus vulgaris on oxidant-induced DNA damage and antioxidant status in HepG2 cells.

Salvia officinalis (SO) and Thymus vulgaris (TV) are medicinal plants well known for their curative powers. However, the molecular mechanisms responsible for these abilities of sage and thyme have not been fully understood yet. In this study we investigated the composition and the quantitative estimation of plant extracts, the protective effects of plant extracts against hydrogen peroxide- and 2,3-dimethoxy-1,4-naphthoquinone-induced DNA damage, and levels of enzymatic and non-enzymatic antioxidants (superoxide dismutase, glutathione peroxidase, glutathione) in human HepG2 cells. To measure antioxidative activity of plant extracts we used three assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The results showed that the oxidant-induced DNA lesions were significantly reduced in cells pre-treated with the plant extracts studied. The observed DNA-protective activity could be explained by both elevation of GPx activity in cells pre-treated with SO and TV and antioxidant activity of SO and TV.