Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heavy alcohol consumption can damage various cells and organs partly through production of reactive oxygen species (ROS) and mitochondrial dysfunction. Treatment with antioxidants can significantly reduce the degree of damage. Despite well established roles of ROS in alcohol-induced cell injury, the proteins that are selectively oxidized by ROS are poorly characterized. We hypothesized that certain cysteinyl residues of target proteins are oxidized by ROS upon alcohol exposure, and these modified proteins may play roles in mitochondrial dysfunction. A targeted proteomics approach utilizing biotin-N-maleimide (biotin-NM) as a specific probe to label oxidized cysteinyl residues was employed to investigate which mitochondrial proteins are modified during and after alcohol exposure. Human hepatoma HepG2 cells with transduced CYP2E1 (E47 cells) were used as a model to generate ROS through CYP2E1-mediated ethanol metabolism. Following exposure to 100 mM ethanol for 4 and 8 h, the biotin-NM-labeled oxidized proteins were purified with agarose coupled to either streptavidin or monoclonal antibody against biotin. The purified proteins were resolved by two-dimensional gel electrophoresis and protein spots that displayed differential abundances were excised from the gel, in-gel digested with trypsin and analyzed for identity utilizing either matrix-assisted laser desorption-time of flight mass spectrometry or microcapillary reversed-phase liquid chromatography-tandem mass spectrometry. The results demonstrate that heat shock protein 60, protein disulfide isomerase, mitochondrial aldehyde dehydrogenases, prohibitin, and other proteins were oxidized after alcohol exposure. The identity of some of the proteins purified with streptavidin-agarose was also confirmed by immunoblot analyses using the specific antibody to each target protein. This method was also used to identify oxidized mitochondrial proteins in the alcohol-fed mouse liver. These results suggest that exposure to ethanol causes oxidation of various mitochondrial proteins that may negatively affect their function and contribute to alcohol-induced mitochondrial dysfunction and cellular injury.
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PMID:Identification of oxidized mitochondrial proteins in alcohol-exposed human hepatoma cells and mouse liver. 1544 75

Aldehyde oxidases are a family of highly related molybdo-flavoenzymes acting upon a variety of compounds of industrial and medical importance. We have identified aldehyde oxidase 1 (AOX1) as a 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) inducible gene in the mouse hepatoma cell line Hepa-1. AOX1 mRNA levels were not increased by dioxin in mutant derivatives of the Hepa-1 cell line lacking either functional aryl hydrocarbon receptor (AHR) or aryl hydrocarbon receptor nuclear translocator (ARNT) proteins, thus demonstrating that transcriptional induction of AOX1 in response to dioxin occurs through the AHR pathway. Dioxin induction of AOX1 mRNA was also observed in mouse liver. In addition, levels of AOX1 protein as well as those of aldehyde oxidase homologue 1 (AOH1), a recently identified homolog of AOX1, were elevated in mouse liver in response to dioxin. Employing an aldehyde oxidase specific substrate, AOX1/AOH1 activity was shown to be induced by dioxin in mouse liver. This activity was inhibited by a known inhibitor of aldehyde oxidases, and eliminated by including tungstate in the mouse diet, which is known to lead to inactivation of molybdoflavoenzymes, thus confirming that the enzymatic activity was attributable to AOX1/AOH1. Our observations thus identify two additional xenobiotic metabolizing enzymes induced by dioxin.
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PMID:Identification of aldehyde oxidase 1 and aldehyde oxidase homologue 1 as dioxin-inducible genes. 1566 68

Steroid and xenobiotic receptor (SXR) or human pregnane X receptor (hPXR) dimerizes with retinoid X receptor (RXR) and regulates the transcription of genes encoding xenobiotic-metabolizing enzymes such as CYP3A4. Rifampin, the classical activator of CYP3A4, binds to SXR directly. It is unclear whether various natural and synthetic retinoids can regulate the expression of CYP3A4. To evaluate the effects of retinoids on the RXR/SXR-mediated pathway, transient transfection assays were performed on both CV-1 and human hepatoma Huh7 cells using a reporter construct containing multiple RXR/SXR consensus binding elements (an everted repeat with a 6-nucleotide spacer, ER-6). The results revealed that eight out of 13 retinoids screened significantly induced the RXR/SXR-mediated pathway in Huh7 cells. At an equal molar concentration, the acid forms (9-cis-RA, 13-cis-RA, and all-trans-RA) or aldehyde, the direct precursor of acid (9-cis-retinal and 13-cis-retinal), exhibited a greater or similar potency than rifampin. Depending on the ligands, RXR may serve as a silent or an active partner of SXR. Additionally, retinoids can increase CYP3A4 enzyme activity in Huh7 cells. To further evaluate the potential drug-drug interactions, which may be caused by retinoids, Huh7 cells were pretreated with 9-cis-RA and followed by acetaminophen. We showed that 9-cis-RA enhanced the covalent binding of N-acetyl-p-quinoneimine, a toxic intermediate of acetaminophen produced by phase I enzymes oxidation. This result suggested that drug-drug interaction might occur between 9-cis-RA and acetaminophen in human liver cells. Taken together, retinoids activate the RXR/SXR-mediated pathway and regulate the expression of CYP3A4. Thus, retinoids potentially can cause drug-drug interactions when they are administered with other CYP3A4 substrates.
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PMID:Retinoids activate the RXR/SXR-mediated pathway and induce the endogenous CYP3A4 activity in Huh7 human hepatoma cells. 1663 23

The aryl hydrocarbon receptor (AhR) is a ligand-activated basic-helix-loop-helix transcription factor that binds polyaromatic hydrocarbons (PAH), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and mediates their toxicity. Binding of PAH to AhR in the cytoplasm triggers a poorly defined transformation step of the receptor into a nuclear transcription factor. In this study, we show that the calcium-dependent cysteine protease calpain plays a major role in the ligand-induced transformation and signaling of AhR. Fluorescence imaging measurements showed that TCDD treatment elevates intracellular calcium, providing the trigger for calpain activation, as measured toward t-butoxycarbonyl-Leu-Met-chloromethylaminocoumarin, a calpain-specific substrate. Inhibition of calpain activity by the N-benzyloxycarbonyl-Val-Phe-aldehyde (MDL28170) blocked the TCDD-induced nuclear translocation of AhR in Hepa1c1c7 mouse hepatoma cell line. Treatment of the human metastatic breast carcinoma cell line MT-2 with MDL28170 and 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD 150606), two calpain-selective inhibitors, completely abolished the TCDD-induced transactivation of AhR as assessed by transcription of CYP1A1 gene. Previous studies have established that after TCDD-induced transactivation, the AhR undergoes a massive depletion; we show here that selective calpain inhibitors can block this step, which suggests that the ligand-induced down-regulation of the AhR is calpain-dependent. The data presented support a major role for calpain in the AhR transformation, transactivation, and subsequent down-regulation, and provide a possible explanation for many of the reported phenomena of ligand-independent activation of AhR.
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PMID:Calpain mediates the dioxin-induced activation and down-regulation of the aryl hydrocarbon receptor. 1718 82

The fruits of Cornus kousa Burg. were extracted with 80% aqueous MeOH, and the concentrated extract partitioned with EtOAc, n-BuOH and H2O. Six lignans were isolated from the EtOAc fraction through repeated silica gel, ODS and Sephadex LH-20 column chromatographies. From the physico-chemical data, including NMR, MS and IR, the chemical structures of the compounds were determined to be (+)-pinoresinol (1), (-)-balanophonin (2), (+)-laricresinol (3), erythro-guaiacylglycerol-beta-coniferyl aldehyde ether (4), threo-guaiacylglycerol-beta-coniferyl aldehyde ether (5) and dihydrodehydrodiconiferyl alcohol (6), which were isolated for the first time from this plant. Most of these compounds showed cytotoxicity against human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG2) cell lines in vitro, with IC50 values ranging from 19.1 to 71.3 microg/mL.
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PMID:Lignans from the fruits of Cornus kousa Burg. and their cytotoxic effects on human cancer cell lines. 1748 53

Alcohol consumption is a significant risk factor for hepatocellular carcinoma (HCC). Alcohol also increases the prevalence of invasion in HCC patients. However, the molecular mechanism on the metastatic effect of alcohol is unclear so far. Herein we demonstrated that acetaldehyde, the primary metabolite of ethanol, increased matrix metalloproteinase-9 (MMP-9) gelatinolytic activity and promoted cell invasion through the up-regulation of MMP-9 gene transcription in HepG2 cells. The transcription of MMP-9 gene was regulated by 10 microM acetaldehyde via inductions of nuclear factor-kappaB (NF-kappaB) and activator protein 1 (AP-1) activities. Acetaldehyde stimulated the translocation of NF-kappaB into nucleus through inhibitory kappaB-alpha (IkappaB-alpha) and c-Jun N-terminal kinase (JNK)/beta-transducin repeat-containing protein (beta-TrCP) signaling pathways. Acetaldehyde also induced AP-1 activity via the phosphorylation of p38 kinase. In conclusion, our findings demonstrated for the first time that acetaldehyde activated NF-kappaB and AP-1 activities via IkappaB, JNK/beta-TrCP, and p38 signaling pathways, resulting in MMP-9 gene expression and hepatocarcinoma cells invasion. These results suggested that acetaldehyde might be a potential factor involved in the invasiveness of HCC in alcoholic patients.
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PMID:Acetaldehyde induces matrix metalloproteinase-9 gene expression via nuclear factor-kappaB and activator protein 1 signaling pathways in human hepatocellular carcinoma cells: Association with the invasive potential. 1754 81

PEGylation which is reversed after the therapeutic agent reaches the target cell presents an attractive feature for drug, protein or nucleic acid delivery. Amine-reactive, endosomal pH cleavable polyethylene glycol aldehyde-carboxypyridylhydrazone, N-hydroxysuccinimide esters (PEG-HZN-NHS) were synthesized and applied for bioreversible surface shielding of DNA polyplexes. Monofunctional mPEG-HZN-NHS was synthesized by reacting succinimidyl hydraziniumnicotinate with mPEG-butyraldehyde (20 kDa). Bifunctional OPSS-PEG-HZN-NHS was synthesized analogously via a omega-2-pyridyldithio-PEG (10 kDa) propionaldehyde intermediate. Polyethylenimine (PEI) polyplexes were reacted with the pH-sensitive (mPEG-HZN-NHS) or the corresponding stable (mPEG-NHS) reagent. Both types of polyplexes remained shielded at pH 7.4 as demonstrated by particle size and zeta potential measurements after 4h of incubation at 37 degrees C. Polyplex deshielding at endosomal pH 5 was observed only with the mPEG-HZN-NHS shielded particles. This was confirmed by fluorescence correlation spectroscopy using the analogous Alexa-488 fluorescently labeled bifunctional PEGylation reagents. Luciferase gene transfections with epidermal growth factor (EGF) containing polyplexes using EGF-receptor overexpressing hepatoma HUH7 cells showed an up to 16-fold enhancement in gene expression with the reversibly shielded polyplexes as compared to stably shielded polyplexes. Consistently, the reversibly shielded polyplexes mediated also an enhanced tumor specific in vivo transgene expression after intravenous administration in a subcutaneous HUH7 tumor model in SCID mice.
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PMID:Amine-reactive pyridylhydrazone-based PEG reagents for pH-reversible PEI polyplex shielding. 1858 70

Previous studies have revealed that acetaldehyde-induced cell invasion and matrix metalloproteinase-9 (MMP-9) activation and are directly involved in hepatic tumorigenesis and metastasis. Acetaldehyde is an important substance for tumor regression. We designed this study to aid in the development of powerful anti-cancer drugs with specific tumor regression and anti-metastatic potentials. Optimal drugs should possess both specific MMP-9 enzyme and gene transcriptional activities at the molecular level. Hesperidin, a flavonoid present in fruits and vegetables, possess anti-inflammatory and chemopreventive activities. Hesperidin suppressed acetaldehyde-induced cell invasion and inhibited the secreted and cytosolic MMP-9 forms in HepG2 cells with acetaldehyde. Hesperidin suppressed acetaldehyde-induced MMP-9 expression through the inhibition of nuclear factor-kappaB (NF-kappaB) and AP-1, and suppressed acetaldehyde-stimulated NF-kappaB translocation into the nucleus through IkappaB inhibitory signaling pathways. Hesperidin also inhibited acetaldehyde-induced AP-1 activity by the inhibitory phosphorylation of p38 kinase and c-Jun N-terminal kinase (JNK) signaling pathways. Results from our study revealed that hesperidin suppressed both acetaldehyde-activated NF-kappaB and activator protein 1 (AP-1) activity by IkappaB, JNK, and p38 signaling pathways. This resulted in the reduction of MMP-9 expression, secretion, and hepatocarcinoma cellular invasion. Our result confirmed the therapeutic potential of hesperidin an anti-metastatic and its involvement in the acetaldehyde-induced cell invasiveness of hepatocellular carcinoma in alcoholic patients.
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PMID:Hesperidin inhibited acetaldehyde-induced matrix metalloproteinase-9 gene expression in human hepatocellular carcinoma cells. 1911 45

To design a novel cytospecific photosensitizer for photodynamic antitumor therapy, a fullerene (C(60)) was chemically modified with pullulan which is a water-soluble polysaccharide with a high affinity for asialoglycoprotein receptors. Ethylene diamine was introduced to the terminal aldehyde groups of pullulan by the reductive amination reaction. Pullulan was coupled to C(60) through the terminal amine group. The C(60) end-group conjugated with pullulan was water-soluble and generated superoxide anion upon light irradiation. The C(60)-pullulan conjugates significantly suppressed the in vitro growth of HepG2 hepatoma cells with asialoglycoprotein receptors, while less suppression activity was observed for HeLa cells without the receptors. The conjugates have a high binding affinity for HepG2 cells, in contrast to HeLa cells. When C(60) was conjugated with polyethylene glycol (PEG) with the similar molecular weight in order to compare the in vitro cell binding and antitumor activities with the C(60)-pullulan conjugate, the dependence of cell type on their activities was not observed. Following the intravenous injection of C(60)-pullulan conjugates to mice carrying a subcutaneous mass of HepG2 cells, significant stronger photodynamic effect on tumor was observed than the intravenous injection of C(60)-PEG conjugates and saline. It is concluded that the pullulan conjugation gave C(60) the targetability to HepG2 cells, resulting in enhanced photodynamic tumor therapy effect.
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PMID:Photodynamic therapy of fullerene modified with pullulan on hepatoma cells. 2018 Jul 50

Eight hydroxyl-substituted Schiff bases with the different number and position of hydroxyl group on the two asymmetric aromatic rings (A and B rings) were prepared by the reaction between the corresponding aromatic aldehyde and aniline. Their antioxidant effects against the stable galvinoxyl radical (GO(.)) in ethyl acetate and methanol, and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced DNA strand breakage, and their antiproliferative effects on human hepatoma HepG2 cells, were investigated. Structure-activity relationship analysis demonstrates that o-dihydroxyl groups on the aromatic A ring and 4-hydroxyl group attached to the aromatic B ring contribute critically to the antioxidant and antiproliferative activities.
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PMID:Antioxidant and antiproliferative activities of hydroxyl-substituted Schiff bases. 2034 60


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