Identification of rhythmic human CYPs and their circadian regulators using synchronized hepatoma cells.

Cytochromes P450 (CYPs) catalyze a great number of metabolic reactions that have profound effects on the biological activities of xenobiotics and endobiotics. In this study, we aimed to characterize rhythmic expressions of drug-metabolizing CYPs using synchronized hepatoma cells, and to investigate the potential roles of cis-elements of circadian clock system (E-box, D-box and RevRE or RORE) in generating the rhythms.Serum was used to synchronize circadian cycles and to induce circadian gene expression in cultured hepatoma cells (HepRG and HepG2 cells). Regulation of CYP genes by circadian clock components was investigated by performing luciferase reporter, overexpression and knockdown experiments. mRNA and protein expression were determined by qPCR and Western blotting assays, respectively.Of ten major drug-metabolizing CYP genes, six are rhythmically expressed (CYP1A2, 2B6, 2C8, 2D6, 2E1 and 3A4), whereas other four are non-rhythmic (CYP1B1, 2A6, 2C9 and 2C19).The E-box binding protein BMAL1 directly controls the rhythmic expression of CYP1A2. Rhythmic expressions of CYP2E1 and CYP3A4 are generated via both E-box and D-box elements. The RevRE binding protein REV-ERBα contributes to rhythmic oscillations in CYP2B6 and CYP2C8.In conclusion, rhythmic expressions of five human CYPs (CYP1A2, 2B6, 2C8, 2E1 and 3A4) are generated and regulated by E-box-, D-box-, and/or RevRE-acting clock components. Our findings may have implications for understanding chronopharmacokinetic events in humans.

Exploration of thioridazine-induced Ca2+ signaling and non-Ca2+-triggered cell death in HepG2 human hepatocellular carcinoma cells.

Thioridazine, belonging to first-generation antipsychotic drugs, is a prescription used to treat schizophrenia. However, the effect of thioridazine on intracellular Ca2+ concentration ([Ca2+]i) and viability in human liver cancer cells is unclear. This study examined whether thioridazine altered Ca2+ signaling and viability in HepG2 human hepatocellular carcinoma cells. Ca2+ concentrations in suspended cells were measured using the fluorescent Ca2+-sensitive dye fura-2. Cell viability was examined by WST-1 assay. Thioridazine at concentrations of 25-100 µM induced [Ca2+]i rises. Ca2+ removal reduced the signal by 20%. Thioridazine (100 µM) induced Mn2+ influx suggesting of Ca2+ entry. Thioridazine-induced Ca2+ entry was inhibited by 20% by protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate) and inhibitor (GF109203X) and by three inhibitors of store-operated Ca2+ channels: nifedipine, econazole, and SKF96365. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) abolished thioridazine-evoked [Ca2+]i rises. On the other hand, thioridazine preincubation completely inhibited the [Ca2+]i rises induced by TG. Furthermore, U73122 totally suppressed the [Ca2+]i rises induced by thioridazine via inhibition of phospholipase C (PLC). Regarding cytotoxicity, at 30-80 µM, thioridazine reduced cell viability in a concentration-dependent fashion. This cytotoxicity was not prevented by preincubation with 1,2-bis (2-aminophenoxy) ethane-N, N, N', N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM) (a Ca2+ chelator). To conclude, thioridazine caused concentration-dependent [Ca2+]i rises in HepG2 human hepatoma cells by inducing Ca2+ release from the endoplasmic reticulum via PLC-associated pathways and Ca2+ influx from extracellular medium through PKC-sensitive store-operated Ca2+ entry. In addition, thioridazine induced cytotoxicity in a Ca2+-independent manner.

In Vitro Study of the Anticancer Effects of Biotechnological Extracts of the Endangered Plant Species Satureja Khuzistanica.

Many medicinal plant species are currently threatened in their natural habitats because of the growing demand for phytochemicals worldwide. A sustainable alternative for the production of bioactive plant compounds are plant biofactories based on cell cultures and organs. In addition, plant extracts from biofactories have significant advantages over those obtained from plants, since they are free of contamination by microorganisms, herbicides and pesticides, and they provide more stable levels of active ingredients. In this context, we report the establishment of Satureja khuzistanica cell cultures able to produce high amounts of rosmarinic acid (RA). The production of this phytopharmaceutical was increased when the cultures were elicited with coronatine and scaled up to a benchtop bioreactor. S. khuzistanica extracts enriched in RA were found to reduce the viability of cancer cell lines, increasing the sub-G0/G1 cell population and the activity of caspase-8 in MCF-7 cells, which suggest that S. khuzistanica extracts can induce apoptosis of MCF-7 cells through activation of the extrinsic pathway. In addition, our findings indicate that other compounds in S. khuzistanica extracts may act synergistically to potentiate the anticancer activity of RA.

[Characterization of Distal and Proximal Alternative Promoters of the Human ApoA-I Gene].

Human apolipoprotein A-I (ApoA-I) is a major structural and functional protein component of high-density lipoprotein (HDL). ApoA-I constitutes ~75% of the protein content of HDL. The main sites of ApoA-I synthesis in humans are the liver and the small intestine. The mechanisms that govern tissue-specific apoA-I transcription in tissues and organs other than the liver and the small intestine are poorly understood. It is known that the human apoA-I has two additional promoters, the proximal and the distal one. In this work these two alternative apoA-I promoters are characterized, their transcription start sites are mapped and their competition for apoA-Itranscription is demonstrated; the role of the alternative promoters in apoA-I expression in human cells and tissues other than hepatocytes and enterocytes is discussed.

[Screening of optimal siRNA interference sequence of CIT gene and its inhibition expression in hepatoma SK-Hep-1].

Objective: To construct and screen optimal siRNA interference sequence of CIT gene and to detect its interference efficiency as well as proliferation effect in human hepatoma cell line SK-Hep-1. Methods: Three siRNA target spots were designed and synthesized according to the CIT gene sequence. SK-Hep-1 HCC cells were transfected by liposome transfection. The knockdown efficiency of the target CIT gene was detected by real-time PCR and Western blot. Expressional change of CIT in SK-Hep-1 cells after 48 hours of siRNA interference were observed by immunohistochemistry and confocal microscopy. The proliferation of SK-Hep-1 cells after 48 hours of siRNA interference was detected by EdU cell proliferation assay. A t-test was used to compare the mean of two samples, and one-way ANOVA was used to compare the mean of multiple samples. Results: Western blot results showed that the three interference sequences were targeted at different target spots. The expression level of CIT protein in KD-1,-2, and-3 groups were decreased (P < 0.01) than control, while the protein expression level of KD1 group was the lowest. Real-time PCR results showed that compared with the control group, the expression level of CIT mRNA in KD-1, -2, and -3 groups decreased (P < 0.01), while that in KD1 group was the lowest. Laser confocal microscopy also confirmed that the morphological expression of CIT attenuated significantly after transfection with siRNA. The results of EdU proliferation assay showed that siRNA transfected with CIT significantly attenuated the proliferation of SK-Hep-1 hepatoma cells (P < 0.05). Conclusion: The successful construction and screening of siRNA fragments can effectively inhibit the expression and proliferation of CIT gene in hepatoma SK-Hep-1.

Effect of Captopril on Ca²âº Homeostasis and Cell Viability in Human Hepatoma Cells.

Captopril, an angiotensin-converting enzyme (ACE) inhibitor, induced different Ca²âº signaling responses in various cell models. However, the effect of captopril on Ca²âº homeostasis and cell viability in hepatoma cells is unknown. This study examined whether captopril altered Ca²âº homeostasis and viability in HepG2 human hepatoma cells. Intracellular Ca²âº concentrations in suspended cells were monitored by using the fluorescent Ca²âº-sensitive dye fura-2. Cell viability was examined by using 4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] water soluble tetrazolium-1 (WST-1). Captopril at concentrations of 500-3000 µM induced [Ca²âº]i rises in a concentration-dependent manner. Ca²âº removal reduced the signal by approximately 15%. Mn²âº has been shown to enter cells through similar mechanisms as Ca²âº but quenches fura-2 fluorescence at all excitation wavelengths. Captopril (3000 µM)-induced Mn²âº influx indirectly suggested that captopril evoked Ca²âº entry. Captopril-induced Ca²âº entry was inhibited by 15% by a protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate, PMA) and an inhibitor (GF109203X) and three inhibitors of store-operated Ca²âº channels: nifedipine, econazole and SKF96365. In Ca²âº-free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished captopril-evoked [Ca²âº]i rises. Conversely, treatment with captopril abolished BHQ-evoked [Ca²âº]i rises. Inhibition of phospholipase C (PLC) with U73122 inhibited 70% of captopril-induced [Ca²âº]i rises. Captopril at concentrations between 150-550 µM killed cells in a concentration-dependent fashion. Chelation of cytosolic Ca²âº with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/AM (BAPTA/AM) did not reverse captopril's cytotoxicity. Together, in HepG2 human hepatoma cells, captopril induced [Ca²âº]i rises and caused cell death that was not triggered by preceding [Ca²âº]i rises.

Ca2+ Signaling and Cell Death Induced by Protriptyline in HepG2 Human Hepatoma Cells.

The effect of protriptyline on Ca2+ physiology in human hepatoma is unclear. This study explored the effect of protriptyline on [Ca2+ ]i and cytotoxicity in HepG2 human hepatoma cells. Protriptyline (50-150 µM) evoked [Ca2+ ]i rises. The Ca2+ entry was inhibited by removal of Ca2+ . Protriptyline-induced Ca2+ entry was confirmed by Mn2+ -induced quench of fura-2 fluorescence. Except nifedipine, econazole, SKF96365, GF109203X, and phorbol 12-myristate 13 acetate did not inhibit Ca2+ entry. Treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) inhibited 40% of protriptyline-induced response. Treatment with protriptyline abolished BHQ-induced response. Inhibition of phospholipase C (PLC) suppressed protriptyline-evoked response by 70%. At 20-40 µM, protriptyline killed cells which was not reversed by the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM). Together, in HepG2 cells, protriptyline induced [Ca2+ ]i rises that involved Ca2+ entry through nifedipine-sensitive Ca2+ channels and PLC-dependent Ca2+ release from endoplasmic reticulum. Protriptyline induced Ca2+ -independent cell death.

The anti-tumor effects of cordycepin-loaded liposomes on the growth of hepatoma 22 tumors in mice and human hepatoma BEL-7402 cells in culture.

Liposomes have successfully been used for decades to encapsulate and protect drugs that are prone to deactivation in the body. The present study aimed to demonstrate the use of liposomes to encapsulate cordycepin, an adenosine analog that quickly loses its activity in vivo. The cordycepin-loaded liposomes were prepared by the ammonium sulfate gradient approach, and its in vitro and in vivo antitumour activities were evaluated using BEL-7402 cells and hepatocellular carcinoma H22 transplanted tumors, respectively. An MTT assay was used to observe the cytotoxicity of cells treated with cordycepin and cordycepin-loaded liposomes in vitro. High-content screening (HSC) was carried out using Hoechst 33342 to detect apoptotic cells and the ratio of cells in different cell cycle stages. The data demonstrated that both the cordycepin and the cordycepin-loaded liposomes resulted in clear cytotoxicity with IC50 values of 18.97 and 29.39 µg/mL, respectively. The latter showed significantly strong inhibitory effects on H22 tumor growth in mice, while the former did not show any inhibitory effects on tumor growth. In addition, the HSC assay showed that the cordycepin-loaded liposomes resulted in a higher rate of apoptosis than the cordycepin alone in BEL-7402 cells. Further data analysis revealed that the cells treated with cordycepin-loaded liposomes were predominately arrested at the G2/M phase (p < 0.05), while those treated with cordycepin alone were arrested in the G0/G1 phase (p < 0.05). In conclusion, these results suggest that liposomes can enhance and maintain the in vivo anti-tumor activity of cordycepin.

Critical Investigation of the Usability of Hepatoma Cell Lines HepG2 and Huh7 as Models for the Metabolic Representation of Resectable Hepatocellular Carcinoma.

Metabolic alterations in hepatocellular carcinoma (HCC) are fundamental for the development of diagnostic screening and therapeutic intervention since energy metabolism plays a central role in differentiated hepatocytes. In HCC research, hepatoma cell lines (HCLs) like HepG2 and Huh7 cells are still the gold standard. In this study, we characterized the metabolic profiles of primary human hepatoma cells (PHCs), HCLs and primary human hepatocytes (PHHs) to determine their differentiation states. PHCs and PHHs (HCC-PHHs) were isolated from surgical specimens of HCC patients and their energy metabolism was compared to PHHs from non-HCC patients and the HepG2 and Huh7 cells at different levels (transcript, protein, function). Our analyses showed successful isolation of PHCs with a purity of 50-73% (CK18+). The transcript data revealed that changes in mRNA expression levels had already occurred in HCC-PHHs. While many genes were overexpressed in PHCs and HCC-PHHs, the changes were mostly not translated to the protein level. Downregulated metabolic key players of PHCs revealed a correlation with malign transformation and were predominantly pronounced in multilocular HCC. Therefore, HCLs failed to reflect these expression patterns of PHCs at the transcript and protein levels. The metabolic characteristics of PHCs are closer to those of HCC-PHHs than to HCLs. This should be taken into account for future optimized tumor metabolism research.

Synthesis of Poly(Malic Acid) Derivatives End-Functionalized with Peptides and Preparation of Biocompatible Nanoparticles to Target Hepatoma Cells.

Recently, short synthetic peptides have gained interest as targeting agents in the design of site-specific nanomedicines. In this context, our work aimed at developing new tools for the diagnosis and/or therapy of hepatocellular carcinoma (HCC) by grafting the hepatotropic George Baker (GB) virus A (GBVA10-9) and Plasmodium circumsporozoite protein (CPB)-derived peptides to the biocompatible poly(benzyl malate), PMLABe. We successfully synthesized PMLABe derivatives end-functionalized with peptides GBVA10-9, CPB, and their corresponding scrambled peptides through a thiol/maleimide reaction. The corresponding nanoparticles (NPs), varying by the nature of the peptide (GBVA10-9, CPB, and their scrambled peptides) and the absence or presence of poly(ethylene glycol) were also successfully formulated using nanoprecipitation technique. NPs were further characterized by dynamic light scattering (DLS), electrophoretic light scattering (ELS) and transmission electron microscopy (TEM), highlighting a diameter lower than 150 nm, a negative surface charge, and a more or less spherical shape. Moreover, a fluorescent probe (DiD Oil) has been encapsulated during the nanoprecipitation process. Finally, preliminary in vitro internalisation assays using HepaRG hepatoma cells demonstrated that CPB peptide-functionalized PMLABe NPs were efficiently internalized by endocytosis, and that such nanoobjects may be promising drug delivery systems for the theranostics of HCC.

Amide-type local anesthetics may suppress tumor cell proliferation and sensitize Human Hepatocellular Carcinoma Cells to Cisplatin via upregulation of RASSF1A expression and demethylation.

Background: It has been reported that local anesthetics are toxic to various types of cells. Furthermore, several local anesthetics have been confirmed to exert demethylation effects and regulate the proliferation of human cancer cells. Our previous findings suggest that lidocaine may exert potential antitumor activity and enhance the sensitivity of cisplatin to hepatocellular carcinoma in vitro and in vivo. A recent study proved that lidocaine sensitizes breast cancer cells to cisplatin via upregulation of RASSF1A, a promotor of tumor suppressive gene (TSG) demethylation. We sought to determine whether amide-type local anesthetics (lidocaine, ropivacaine and bupivacaine) exert growth-inhibitory effects on human hepatoma cells and to determine whether amide-type local anesthetics sensitize human hepatoma cells to cisplatin-mediated cytotoxicity via upregulation of RASSF1A expression. Methods: Human hepatoma cell lines HepG2 and BEL-7402 were incubated with lidocaine, ropivacaine and bupivacaine. The viability of local anesthetic-treated cells with or without cisplatin was investigated. Further, we evaluated RASSF1A expression after treatment of HepG2 and BEL-7402 cells with three local anesthetics and determined the influence of RASSF1A expression on the toxicity of cisplatin to these cells. Results: The viability of HepG2 and BEL-7402 cells was significantly decreased by treatment with amide-type local anesthetics (lidocaine, ropivacaine and bupivacaine). In these cells, the combination treatment with cisplatin and local anesthetics exhibited a stronger reduction in viability. Lidocaine, ropivacaine and bupivacaine promoted a significant increase in RASSF1A expression and a decrease in RASSF1A methylation. The combined treatment with both local anesthetics and cisplatin resulted in a significantly lower level of HepG2 and BEL-7402 cell viability than that with singular local anesthetics or cisplatin treatment. Moreover, local anesthetics enhanced the cytotoxicity of cisplatin against HepG2 and BEL-7402 cells, accompanied by an increase in RASSF1A expression. Conclusions: These data indicated that amide-type local anesthetics (lidocaine, ropivacaine and bupivacaine) have growth-inhibitory and demethylation effects in human hepatoma cells. We also found that these amide local anesthetics may enhance the cytotoxicity of cisplatin in human hepatocellular carcinoma cells possibly via upregulation of RASSF1A expression and demethylation.

Human alcohol dehydrogenase 1 is an acceptor protein for polyADP-ribosylation.

Alcohol dehydrogenase (ADH) is important for preventing alcohol toxicity and developmental disorders, and may be involved in other diseases including neurodegenerative diseases. We found that the major acceptor protein of polyADP-ribosylation in a model organism of neurodegeneration using a Drosophila melanogaster mutant lacking poly(ADP-ribose) glycohydrolase, was ADH. Thus we postulated that human ADH activity might be regulated by polyADP-ribosylation, a post-translational modification. The radioactivity of [32P]NAD+ was incorporated into human ADH1 by human poly(ADP-ribose) polymerase 1 in vitro, but was not incorporated when heat-inactivated PARP1 or a PARP inhibitor, 3-aminobenzamide, was used. The incorporated radioactivity was not released from ADH1 protein in the presence of excess amount of ADP-ribose or poly(ADP-ribose) as competitors. However, it was released by incubation with 1 M neutral NH2OH or 0.1 N NaOH, but was not with 0.1 N HCl, suggesting the bond between ADH1 and poly(ADP-ribose) is an ester linkage. When HepG2 cells, a human hepatoma cell line, were cultured in the presence of another PARP inhibitor, olaparib, ADH activity of the cell was significantly increased. These results suggest that polyADP-ribosylation could regulate ADH activity in vivo and might be involved in neurodegeneration.

Zingerone Nanotetramer Strengthened the Polypharmacological Efficacy of Zingerone on Human Hepatoma Cell Lines.

We base this study on the concept of drug repositioning to reconstitute the natural product of zingerone as zingerone nanoparticles (zingerone NPs) through a one-pot synthesized process. The as-fabricated zingerone NPs were characterized; they possessed a particle size of 1.42 ± 0.67 nm and a reconstituted structure of zingerone nanotetramer. We further validate the effects of zingerone NPs on the antitumor activity and investigate the relative underlying mechanisms on the human hepatoma SK-Hep-1 and Huh7 cell lines. Our results demonstrated that zingerone NPs significantly inhibit Akt activity and NFκB expression as well as activate the caspases cascade signaling pathway which are involved in the antiproliferation, antitumorigenicity, disturbing cell cycle progression, and induction of DNA damage as well as cell apoptosis. These findings were promising to provide a "Nano-chemoprevention" strategy in future cancer therapeutics and medical and clinical applications.

Intake of ergosterol increases the vitamin D concentrations in serum and liver of mice.

Factors that can modify the bioavailability of orally administered vitamin D are not yet widely known. Ergosterol is a common fungal sterol found in food which has a chemical structure comparable to that of vitamin D. This study aimed to investigate the effect of ergosterol on vitamin D metabolism. Therefore, 36 male wild type-mice were randomly subdivided into three groups (n = 12) and received a diet containing 25 µg vitamin D3 and either 0 mg (control), 2 mg or 7 mg ergosterol per kg diet for 6 weeks. To elucidate the impact of ergosterol on hepatic hydroxylation of vitamin D, human hepatoma cells (HepG2) were treated with different concentrations of ergosterol. Concentrations of vitamin D3 and 25-hydroxyvitamin D3 (25(OH)D3) in cells, livers and kidneys of mice and additionally 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) in serum were quantified by LC-MS/MS. The concentration of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in serum was analyzed by commercially-available enzyme immuno assay. The concentrations of cholesterol and triglycerides were analyzed in livers of mice by photometric assays. Analyses revealed that mice receiving 7 mg/kg ergosterol with their diet had 1.3-, 1.7- and 1.5-times higher concentrations of vitamin D3 in serum, liver and kidney, respectively, than control mice (P < 0.05), whereas no significant effects were observed in mice fed 2 mg/kg ergosterol. The hydroxylation of vitamin D remained unaffected by dietary ergosterol, since the concentration of 25-hydroxyvitamin D3 in serum and tissues and the concentrations of 1,25(OH)2D3 and 24,25(OH)2D3 in serum were not different between the three groups of mice. The lipid concentrations in liver were also not affected by dietary ergosterol. Data from the cell culture studies showed that ergosterol did not influence the conversion of vitamin D3 to 25(OH)D3. To conclude, ergosterol appears to be a modulator of vitamin D3 concentrations in the body of mice, without modulating the hydroxylation of vitamin D3 in liver.

Immunotherapy of Hepatocellular Carcinoma with Magnetic PD-1 Peptide-Imprinted Polymer Nanocomposite and Natural Killer Cells.

Programmed cell death protein 1 (PD-1) is a biomarker on the surface of cells with a role in promoting self-tolerance by suppressing the inflammatory activity of T cells. In this work, one peptide of PD-1 was used as the template for molecular imprinting to form magnetic peptide-imprinted poly(ethylene-co-vinyl alcohol) composite nanoparticles (MPIP NPs). The nanoparticles were characterized by dynamic light scattering (DLS), high-performance liquid chromatography (HPLC), Brunauer-Emmett-Teller (BET) analysis, and superconducting quantum interference device (SQUID) analysis. Natural killer 92 (NK-92) cells were added to these composite nanoparticles and then incubated with human hepatoma (HepG2) cells. The viability and the apoptosis pathway of HepG2 were then studied using cell counting kit-8 (CCK8) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. These nanoparticles were found to significantly enhance the activity of natural killer cells toward HepG2 cells by increasing the expression of nuclear factor kappa B (NF-κB), caspase 8, and especially caspase 3.

Novel 1,4-naphthoquinone derivatives induce apoptosis via ROS-mediated p38/MAPK, Akt and STAT3 signaling in human hepatoma Hep3B cells.

1,4-Naphthoquinone and its derivatives have shown some efficacy as therapeutic compounds for cancer and inflammation, though their clinical application is limited by their side-effects. To reduce the toxicity of these compounds and optimize their effects, we synthesized two 1,4-naphthoquinone derivatives-2-butylsulfinyl- 1,4-naphthoquinone (BSNQ) and 2-octylsulfinyl-1,4-naphthoquinone (OSNQ)-and investigated their effects and underlying mechanisms in hepatocellular carcinoma cells. BSNQ and OSNQ decreased cell viability and significantly induced apoptosis, accompanied by the accumulation of reactive oxygen species (ROS). However, pretreatment with N-acetyl-l-cysteine, a specific ROS scavenger, blocked apoptosis. Western blot results indicated that BSNQ and OSNQ up-regulated the phosphorylation of p38 and JNK, and down-regulated the phosphorylation of ERK, Akt and STAT3, and that these effects were blocked by N-acetyl-l-cysteine. Furthermore, BSNQ and OSNQ suppressed tumor growth and modulated MAPK and STAT3 signaling in mouse xenografts without detectable effects on body weight or hematological parameters. These results indicate that BSNQ and OSNQ induce apoptosis in human hepatoma Hep3B cells via ROS-mediated p38/MAPK, Akt and STAT3 signaling pathways, suggesting that these 1,4-naphthoquinone derivatives may provide promising new anticancer agents to treat HCC.

The effects of urotensin II on migration and invasion are mediated by NADPH oxidase-derived reactive oxygen species through the c-Jun N-terminal kinase pathway in human hepatoma cells.

AIMS: Urotensin II (UII) is a vasoactive neuropeptide involved in migration and invasion in various cell types. However, the effects of UII on human hepatoma cells still remain unclear. The aim of this study was to investigate the role and mechanism of UII on migration and invasion in human hepatoma cells. METHODS: Migration was measured by wound healing assays and a Transwell® methodology, and invasion was analyzed using Matrigel® invasion chambers. Reactive oxygen species (ROS) levels were detected using a 2', 7'-dichlorofluorescein diacetate probe, and flow cytometry, and protein expression levels were evaluated by western blotting. Cell proliferation and actin polymerization were examined using cell proliferation reagent WST-1 and F-actin immunohistochemistry staining. RESULTS: Exposure to UII promoted migration and invasion in hepatoma cells compared with that in cells without UII. UII also increased matrix metalloproteinase-2 (MMP2) expression in a time-independent manner. Furthermore, UII markedly enhanced ROS generation and NADPH oxidase subunit expression, and consequently facilitated the phosphorylation of c-Jun N-terminal kinase (JNK). The UT antagonist urantide or the antioxidant/NADPH oxidase inhibitor apocynin decreased UII-induced ROS production. JNK phosphorylation, migration, invasion, and MMP9/2 expression were also reversed by pretreatment with apocynin. Urantide and JNK inhibitor SP600125 abrogated migration, invasion, or MMP9/2 expression in response to UII. UII induced actin polymerization and fascin protein expression, and could be reversed by apocynin and SP600125. CONCLUSIONS: Exogenous UII induced migration and invasion in hepatoma cells that mainly involved NADPH oxidase-derived ROS through JNK activation. UT played an additional role in regulating hepatoma cells migration and invasion. Thus, our data suggested an important effect of UII in hepatocellular carcinoma metastasis.

Induction by arsenate of cell-type-specific cytotoxic effects in nerve and hepatoma cells.

The aim of the study was to compare the effect of sodium arsenate (AsV) on two different cell types: 158N murine oligodendrocytes and HepG2 human hepatoma cells. Exposure of 158N cells to AsV (0.1-400 µM; 48 h) induced a biphasic cytoxic effect defined as hormesis. Thus, low concentrations of AsV stimulate cell proliferation, as shown by phase-contrast microscopy, cell counting with trypan blue, and crystal violet assay, whereas high concentrations induce cell death associated with a loss of cell adhesion. These side effects were confirmed by staining with propidium iodide and cell cycle analysis, characterized by the presence of a subG1 peak, a criterion of apoptosis. The effects of AsV on mitochondrial function, as determined by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay, the measurement of mitochondrial transmembrane potential with 3,3'-dihexyloxacarbocyanine iodide, and the rate of mitochondrial adenosine triphosphate confirm the impact of AsV on the mitochondria. In contrast to 158N cells, HepG2 cells were susceptible to all AsV concentrations as shown by microscopic observations, by counting with trypan blue. However, no alteration is noted in the cell membrane integrity, which indicated an apoptotic mode of cell death, and this side effect is confirmed by the cycle analysis, which revealed a subG1 peak. Of note, there was a loss of MTT, suggesting that AsV induces mitochondrial complex II dysfunction. Altogether, our data show that the cytotoxic characteristics of AsV depend on the cell type considered.

Effects of Oxymatrine on the Proliferation and Apoptosis of Human Hepatoma Carcinoma Cells.

Oxymatrine, one of the main active components of extracts from the dry roots of Sophora flavescens, has been reported to possess anticancer activities in vitro and in vivo However, the precise mechanism involved remains largely unknown. The present study is conducted to investigate the anticancer activity and the underlying mechanisms of oxymatrine in human hepatoma cells (Hep-G2 and SMMC-7721) in vitro and in vivo Hep-G2 and SMMC-7721 cells were treated by oxymatrine and subjected to methyl thiazolyl tetrazolium analysis, Hoechst 33342 staining, annexin V/propidium iodide double staining, reverse transcription polymerase chain reaction, and Western blot analysis. In addition, SMMC-7721 xenograft tumors were established in male nude BALB/c mice, and oxymatrine was intravenously administered to evaluate the anticancer capacity in vivo Our results showed that oxymatrine inhibited the proliferation and induced apoptosis of Hep-G2 and SMMC-7721 cells in a dose-dependent manner in vitro Furthermore, the RNA and protein expression of Bax and caspase 3 levels were significantly upregulated, whereas the expression of Bcl-2 was downregulated. These protein interactions may play a pivotal role in the regulation of proliferation and apoptosis. More importantly, our in vivo studies showed that administration of oxymatrine decreased tumor growth in a dose-dependent manner. Immunohistochemistry analysis demonstrated an increase of Bax and caspase 3 and a decrease of Bcl-2 in tumor tissues following oxymatrine treatment which are consistent with the in vitro results. Taken together, our findings indicated that oxymatrine can inhibit cell proliferation and induce apoptosis of human hepatoma Hep-G2 and SMMC-7721 cells and might offer a therapeutic potential advantage for human hepatoma chemoprevention or chemotherapy.

The effect of oleuropein from olive leaf (Olea europaea) extract on Ca²âº homeostasis, cytotoxicity, cell cycle distribution and ROS signaling in HepG2 human hepatoma cells.

Oleuropein, a phenolic compound found in the olive leaf (Olea europaea), has been shown to have biological activities in different models. However, the effects of oleuropein on Ca(2+) homeostasis, cytotoxicity, cell cycle distribution and ROS signaling in liver cells have not been analyzed. Oleuropein induced [Ca(2+)]i rises only in HepG2 cells but not in AML12, HA22T or HA59T cells due to the different status of 3-hydroxy-3-methylglutaryl-CoA reductase expression. In HepG2 cells, this Ca(2+) signaling response was reduced by removing extracellular Ca(2+), and was inhibited by the store-operated Ca(2+) channel blockers 2-APB and SKF96365. In Ca(2+)-free medium, pretreatment with the ER Ca(2+) pump inhibitor thapsigargin abolished oleuropein-induced [Ca(2+)]i rises. Oleuropein induced cell cycle arrest which was associated with the regulation of p53, p21, CDK1 and cyclin B1 levels. Furthermore, oleuropein elevated intracellular ROS levels but reduced GSH levels. Treatment with the intracellular Ca(2+) chelator BAPTA-AM or the antioxidant NAC partially reversed oleuropein-induced cytotoxicity. Together, in HepG2 cells, oleuropein induced [Ca(2+)]i rises by releasing Ca(2+) from the ER and causing Ca(2+) influx through store-operated Ca(2+) channels. Moreover, oleuropein induced Ca(2+)-associated cytotoxicity that involved ROS signaling and cell cycle arrest. This compound may offer a potential therapy for treatment of human hepatoma.