Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Dedifferentiated hepatoma cells, in contrast to most other cell types including hepatoma cells, undergo apoptosis when treated with lipopolysaccharide (LPS) plus the protein synthesis inhibitor cycloheximide (CHx). We recently reported that the dedifferentiated hepatoma cells also exhibit a strong and prolonged NF-kappaB induction phenotype upon exposure to LPS, suggesting that NF-kappaB signaling may play a pro-survival role, as reported in several other cell systems. To test the role of NF-kappaB in preventing LPS-mediated apoptosis, we examined the dedifferentiated cell line M38. Results show that antioxidants strongly inhibited LPS + CHx-mediated cell death in the M38 cells, yet only modestly inhibited NF-kappaB induction. In addition, inhibition of NF-kappaB translocation by infection of the M38 cells with an adenoviral vector expressing an IkappaBalpha super-repressor did not result in LPS-mediated cell death. These results suggest that unlike TNFalpha induction, the cell survival pathway activated in response to LPS is independent of NF-kappaB translocation in the dedifferentiated cells. Addition of inhibitors of JNK, p38 and ERK pathways also failed to elicit LPS-mediated apoptosis similar to that observed when protein synthesis is prevented. Thus, cell survival pathways other than those involving NF-kappaB inducible gene expression or other well-known pathways appear to be involved in protecting the dedifferentiated hepatoma variant cells from LPS-mediated apoptosis. Importantly, this pro-apoptotic function of LPS appears to be a function of loss of hepatic gene expression, as the parental hepatoma cells resist LPS-mediated apoptosis in the presence of protein synthesis inhibitors.
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PMID:Apoptosis of dedifferentiated hepatoma cells is independent of NF-kappaB activation in response to LPS. 1765 37

Cinnamaldehyde (Cin) has been shown to be effective in inducing apoptotic cell death in a number of human cancer cells. The aim of this study was to investigate the effect of pifithrin-alpha (PFTalpha; a specific p53 inhibitor) and mitogen-activated protein kinases (MAPKs) inhibitors [namely SP600125 (a specific JNK inhibitor), SB203580 (a specific p38 inhibitor) and PD98059 (a specific ERK inhibitor)] on apoptotic signaling transduction mechanism induced by Cin in human hepatoma PLC/PRF/5 (CD95-negative) cells. Using XTT assay, Cin exhibited a powerful cytotoxic effect and apoptotic induction in PLC/PRF/5 cells. Apoptosis was elicited when cells were treated with 1 microM Cin as characterized by morphological changes and the appearance of phosphatidylserine on the outer surface of the plasma membrane. Cin down-regulated the expression of Bcl-(XL), up-regulated mutant p53 and Bax proteins and promoted caspase-3 to active forms, as well as cleaving poly (ADP-ribose) polymerase (PARP) in a time-dependent pattern. This could be supported by the activation and phosphorylation of MAPKs, including JNK, ERK and p38 kinases. Pre-incubation with PFTalpha and specific MAPK inhibitors significantly diminished the effect of Cin-induced apoptosis. The activities of anti-apoptotic (Bcl-(XL)) and pro-apoptotic (Bax) proteins were remarkably affected by PFTalpha and PD98059 pre-treatment. PFTalpha effectively blocked PARP cleavage in cells treated with Cin, and also markedly prevented the phosphorylation of JNK, p38 and ERK proteins. These results suggest that p53 induction and MAPK signaling pathways are required for Cin-mediated apoptosis in PLC/PRF/5 cells.
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PMID:MAPK inhibitors and pifithrin-alpha block cinnamaldehyde-induced apoptosis in human PLC/PRF/5 cells. 1767 46

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide, accounting for an estimated 600,000 deaths annually. Aberrant methylation, consisting of DNA hypomethylation and/or promoter gene CpG hypermethylation, is implicated in the development of a variety of solid tumors, including HCC. We analyzed the global levels of DNA methylation as well as the methylation status of 105 putative tumor suppressor genes and found that the extent of genome-wide hypomethylation and CpG hypermethylation correlates with biological features and clinical outcome of HCC patients. We identified activation of Ras and downstream Ras effectors (ERK, AKT, and RAL) due to epigenetic silencing of inhibitors of the Ras pathway in all HCC. Further, selective inactivation of SPRY1 and -2, DAB2, and SOCS4 and -5 genes and inhibitors of angiogenesis (BNIP3, BNIP3L, IGFBP3, and EGLN2) was associated with poor prognosis. Importantly, several epigenetically silenced putative tumor suppressor genes found in HCC were also inactivated in the nontumorous liver. Our results assign both therapeutic and chemopreventive significance to methylation patterns in human HCC and open the possibility of using molecular targets, including those identified in this study, to effectively inhibit HCC development and progression.
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PMID:Mechanistic and prognostic significance of aberrant methylation in the molecular pathogenesis of human hepatocellular carcinoma. 1771 5

Erythropoietin-producing hepatoma-amplified sequence (Eph) receptor tyrosine kinases and their cell-surface-bound ligands, the ephrins, function as a unique signaling system triggered by cell-to-cell interaction and have been shown to mediate neurodevelopmental processes. In addition, recent studies showed deregulation of some of Eph/ephrin genes in human malignancies, suggesting the involvement of this signaling pathway in tumorigenesis. The ALL1 (also termed MLL) gene on human chromosome 11q23 was isolated by virtue of its involvement in recurrent chromosome translocations associated with acute leukemias with poor prognosis. The translocations fuse ALL1 to any of >50 partner genes and result in production of chimeric proteins composed of the ALL1 N terminus and the C terminus of the partner protein. The most common translocations in ALL1-associated leukemias are t(4;11) and t(9;11), which generate ALL1/AF4 and ALL1/AF9 fusion protein, respectively. In the present study, we sought to determine whether ALL1 fusion proteins are involved in regulation of Eph/ephrin genes. Screening of K562 cells producing recombinant ALL1/AF4 or ALL1/AF9 fusion protein revealed transcriptional up-regulation of the EphA7. Consistent with this finding, siRNA-mediated suppression of ALL1/AF4 in SEMK2 cells carrying the t(4;11) chromosome translocation resulted in down-regulation of EphA7. ChIP analysis demonstrated the occupancy of tagged ALL1 fusion proteins on the EphA7 promoter, pointing to EphA7 as a direct target of the formers. Further studies demonstrate that EphA7 up-regulation is accompanied by ERK phosphorylation. Finally, we show apoptotic cell death, specific for leukemic cells carrying the t(4;11) chromosome translocation, after treatment of the cells with an ERK phosphorylation blocker.
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PMID:ALL1 fusion proteins induce deregulation of EphA7 and ERK phosphorylation in human acute leukemias. 1772 5

Certain selective serotonin reuptake inhibitors (SSRIs) induce the clinical and biochemical manifestations of a metabolic syndrome by as yet unknown mechanism. Here we demonstrate that incubation (1 h) of rat hepatoma Fao cells with the SSRIs paroxetine and sertraline, but not with the atypical antipsychotic drug olanzapine, inhibited the insulin-stimulated Tyr phosphorylation of the insulin receptor substrate-1 (IRS-1) with half-maximal effects at approximately 10 microM. This inhibition correlated with a rapid phosphorylation and activation of a number of Ser/Thr IRS-1 kinases including JNK, S6K1, ERK and p38 MAPK, but not PKB (Akt). JNK appears as a key player activated by SSRIs because specific JNK inhibitors partially eliminated the effects of these drugs. The SSRIs induced the phosphorylation of IRS-1 on S307 and S408, which inhibits IRS-1 function and insulin signaling. These results implicate selected SSRIs as inhibitors of insulin signaling and as potential inducers of cellular insulin resistance.
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PMID:Antidepressants induce cellular insulin resistance by activation of IRS-1 kinases. 1772 40

Fludarabine is the major drug against chronic lymphoblastic leukemia. However, the effects of fludarabine on solid tumors remain unclear. We reported previously that fludarabine inhibited expression of hypoxia-inducible factor 1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in human ovarian cancer cells. The present study aims to investigate, (1) the mechanisms that fludarabine inhibits expression of HIF-1alpha and (2) the effects of fludarabine on tumor cells survival under hypoxia. Human hepatoma HepG2 cells were tested. We found that fludarabine reduced HIF-1alpha stability through prolyl hydroxylation. Fludarabine suppressed hypoxia-induced expression of VEGF and its receptor KDR. It inhibited VEGF-induced activation of AKT and ERK signaling and reduced hypoxia-enhanced HepG2 cell survivability. HepG2 cells were much more sensitive to fludarabine treatment under hypoxia than under nomoxia. These results suggest that fludarabine reduces survivability of HepG2 cells via VEGF signaling under hypoxia.
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PMID:Fludarabine reduces survivability of HepG2 cells through VEGF under hypoxia. 1796 96

Hepatocyte growth factor (HGF) and its receptor, Met, known to control invasive growth program have recently been shown to play crucial roles in the survival of breast cancer patients. The diet-derived flavonoids have been reported to possess anti-invasion properties; however, knowledge on the pharmacological and molecular mechanisms in suppressing HGF/Met-mediated tumor invasion and metastasis is poorly understood. In our preliminary study, we use HGF as an invasive inducer to investigate the effect of flavonoids including apigenin, naringenin, genistein and kaempferol on HGF-dependent invasive growth of MDA-MB-231 human breast cancer cells. Results show that apigenin presents the most potent anti-migration and anti-invasion properties by Boyden chamber assay. Furthermore, apigenin represses the HGF-induced cell motility and scattering and inhibits the HGF-promoted cell migration and invasion in a dose-dependent manner. The effect of apigenin on HGF-induced signaling activation involving invasive growth was evaluated by immunoblotting analysis, it shows that apigenin blocks the HGF-induced Akt phosphorylation but not Met, ERK, and JNK phosphorylation. In addition to MDA-MB-231 cells, apigenin exhibits inhibitory effect on HGF-induced Akt phosphorylation in hepatoma SK-Hep1 cells and lung carcinoma A549 cells. By indirect immunofluorescence microscopy assay, apigenin inhibits the HGF-induced clustering of beta 4 integrin at actin-rich adhesive site and lamellipodia through PI3K-dependent manner. Treatment of apigenin inhibited HGF-stimulated integrin beta 4 function including cell-matrix adhesion and cell-endothelial cells adhesion in MDA-MB-231 cells. By Akt-siRNA transfection analysis, it confirmed that apigenin inhibited HGF-promoted invasive growth involving blocking PI3K/Akt pathway. Finally, we evaluated the effect of apigenin on HGF-promoted metastasis by lung colonization of tumor cells in nude mice and organ metastasis of tumor cells in chick embryo. By histological and gross examination of mouse lung and real-time PCR analysis of human alu in host tissues, it showed that apigenin, wortmannin, as well as anti-beta 4 antibody all inhibit HGF-promoted metastasis. These data support the inhibitory effect of apigenin on HGF-promoted invasive growth and metastasis involving blocking PI3K/Akt pathway and integrin beta 4 function.
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PMID:Apigenin inhibits HGF-promoted invasive growth and metastasis involving blocking PI3K/Akt pathway and beta 4 integrin function in MDA-MB-231 breast cancer cells. 1796 21

Hepatitis C virus (HCV) causes chronic hepatitis, which often results in the development of liver cirrhosis and hepatocellular carcinoma (HCC) worldwide. In this study, we demonstrated that the non-structural protein NS3 of HCV enhances cyclooxygenase-2 (COX-2) gene promoter activity, COX-2 mRNA expression, COX-2 protein production, and prostaglandin E2 (PGE2) release in HepG2 cells in a concentration-dependent fashion. We also showed that transcription factor NF-kappaB is required for the activation of COX-2 regulated by NS3. In addition, multiple signaling pathways are involved cooperatively in the expression of COX-2 activated by the viral protein in a calcium-independent manner, which requires signaling components including JNK, ERK, and PKD2. A thorough investigation of mechanism involved in the activation of COX-2 regulated by HCV would provide insights into our understanding the processes of liver inflammatory response and hepatocellular carcinoma development caused by the viral infection and also into the development of novel therapeutics against HCV infection.
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PMID:NS3 protein of hepatitis C virus regulates cyclooxygenase-2 expression through multiple signaling pathways. 1796 30

The genus Erythrina (Leguminosae), consisting of over 100 different species, is distributed in tropical regions. In traditional medicine, Erythrina species are used to treat cancer, but little is known about the anticancer mechanisms. From the stem bark of Erythrina addisoniae Hutch. & Dalziel, six prenylated pterocarpans were isolated and analysed for pharmacological activity: While calopocarpin, cristacarpin, orientanol c, and isoneorautenol showed only a weak or moderate toxicity in H4IIE hepatoma cells (EC(50)-value> 25 microM), the toxicity of neorautenol and phaseollin was in the low micromolar range (EC(50)-value: 1 and 1.5 microM, respectively). We further focused on these two substances showing that both increased caspase 3/7 activity and nuclear fragmentation as markers for apoptotic cell death. Neorautenol (10 microM, 2h), but not phaseollin induced the formation of DNA strand breaks (comet assay). Both substances showed no effect on NF-kappaB signalling (SEAP assay: basal activity and stimulation with TNF-alpha), on the other hand both pterocarpans (10 microM, 2 h) decreased the activation of the ERK kinase (p44/p42), an mitogen activated protein kinase which is associated with cell proliferation. We conclude that the pterocarpans phaseollin and neorautenol may be responsible for the anticarcinogenic actions of the plant extract reported in the literature. Further analysis of these substances may lead to new pharmacons to be used in cancer therapy.
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PMID:Pterocarpans phaseollin and neorautenol isolated from Erythrina addisoniae induce apoptotic cell death accompanied by inhibition of ERK phosphorylation. 1796 4

Smilax glabra Roxb. (SGR) is the root of a traditional Chinese herb, referred to as tu fu ling in Chinese medicine. It is an inexpensive traditional Chinese medicine commonly used for the treatment of liver diseases, and a few studies have indicated that SGR has anti-hepatocarcinogenic and anti-cancer growth activities. In the current study, raw SGR plant was extracted with Accelerate Solvent Extractor, and the molecular mechanism by which S. glabra Roxb. extract (SGRE) has an anti-proliferative effect on the human hepatoma cell lines, HepG2 and Hep3B, was determined. We showed that SGRE inhibited HepG2 and Hep3B cell growth by causing cell-cycle arrest at either S phase or S/G2 transition and induced apoptosis, as evidenced by a DNA fragmentation assay. SGRE-induced apoptosis by alternation of mitochondrial transmembrane depolarization, release of mitochondrial cytochrome c, activation of caspase-3, and cleavage of poly(ADP-ribose) polymerase. The SGRE-mediated mitochondria-caspase dependent apoptotic pathway also involved activation of p38, JNK, and ERK mitogen-activated protein kinase signaling. Isometric compounds of astilbin (flavonoids) and smilagenin (saponin) have been identified as the main chemical constituents in SGRE by HPLC-MS/MS. These results have identified, for the first time, the biological activity of SGRE in HepG2 and Hep3B cells and should lead to further development of SGR for liver disease therapy.
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PMID:Anti-proliferative and pro-apoptotic effect of Smilax glabra Roxb. extract on hepatoma cell lines. 1799 28


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