Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0345904 (liver cancer)
 15,188 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Akt/PI-3 kinase pathway is a system essential for cell survival. In the current study, we showed that hepatocyte growth factor (HGF) activates the Akt/PI-3 kinase pathway to suppress Fas-mediated cell death in human hepatocellular carcinoma (HCC; 3 lines; SK-Hep1, HLE, and Chang Liver cell lines), hepatoblastoma (1 line; HepG2), and embryonic hepatocyte (1 line; WRL). Five tested cell lines showed the resistance to Fas-mediated cell death by the pretreatment of HGF. This HGF-induced cell survival was suppressed by wortmannin (Akt/PI-3 kinase pathway inhibitor), suggesting an involvement of Akt. When cells were pretreated with HGF, Fas-mediated cell death was suppressed, followed by Akt phosphorylation at Ser473. Fas-death-inducing signaling complex (DISC) formation, especially FADD and caspase 8 interaction, was suppressed by HGF and the suppression of the Akt/PI-3 kinase pathway by transient expression of PTEN, resulting in acquisition of Fas-DISC formation and Fas-mediated cell death in HGF-treated cells. We suggest that HGF promotes cell survival in hepatocyte-derived cell lines (HCC, hepatoblastoma, and embryonic hepatocyte) from Fas-mediated cell death via Fas-DISC suppression as a result of Akt activation.
 ...
PMID:Hepatocyte growth factor promotes cell survival from fas-mediated cell death in hepatocellular carcinoma cells via Akt activation and Fas-death-inducing signaling complex suppression. 1100 25

Cell death induction by cytotoxic T lymphocytes (CTLs) is an important thesis for the understanding of tumor immunotherapy. In the current study we investigated the molecular machinery of CTL-induced cell death in human hepatocellular carcinoma cell lines (HCC lines). CTLs prepared from human peripheral blood induced cell death in all tested HCC lines. As the CTL-induced death system, the effectiveness of Fas ligand/Fas and/or Perforin/Granzyme B systems has been suggested, whereas cell death induction by CTLs was shown independently on Fas expression in the current study. Using various tetrapeptide inhibitors for caspase and its associated factor, we additionally demonstrated that inhibitors for caspase 3 (Ac-DEVD-CHO) and caspase 8/granzyme B (Ac-IETD-CHO) suppressed CTL-induced cell death, but an inhibitor for Fas-activated serine proteinase, which acts for the caspase 3 activator, did not, suggesting that CTL-induced cell death was initiated by the Perforin/Granzyme B system, rather than the Fas ligand/Fas system. On the basis of our current results, we report here that the Perforin/Granzyme B system acts dominantly for the cell death induction of HCC lines.
 ...
PMID:Cell death induction by CTL: perforin/granzyme B system dominantly acts for cell death induction in human hepatocellular carcinoma cells. 1104 57

Boswellic acids are the compounds isolated from the gum resin of Boswellia serrata and have been used for the treatment of inflammatory diseases for many years in the countries of the east. Recently, a few studies showed that the acids may have anti-cancer effect on leukemia and brain tumours. We investigated the apoptotic and anti-proliferative effects of two types of boswellic acids, keto-beta-boswellic acid and acetyl-keto-beta-boswellic acid, on liver cancer Hep G2 cells. After treating the cells with the boswellic acids, cell proliferation, DNA synthesis, and apoptosis were analysed. The activities of caspase-3, -8 and -9 were assayed. To explore the apoptotic pathway, specific caspase inhibitors were employed. It was found that boswellic acids decreased cell viability and [3H]thymidine incorporation, checked the cells in the G1 phase, and increased percentage of sub-G1. Boswellic acids strongly induced apoptosis accompanied by activation of caspase-3, -8 and -9. The apoptosis was blocked completely by caspase-8 or caspase-3 inhibitor, but inhibited partly by caspase-9 inhibitor. However, these caspase inhibitors did not show any effect on the alternations of cell viability caused by boswellic acids. In conclusion, boswellic acids have anti-proliferation and anti-cancer effects on Hep G2 cells. The apoptotic effect is mediated by a pathway dependent on caspase-8 activation. The acids may be a promising drug for the chemoprevention of liver cancer.
 ...
PMID:Keto- and acetyl-keto-boswellic acids inhibit proliferation and induce apoptosis in Hep G2 cells via a caspase-8 dependent pathway. 1223 1

Despite its implication in the progression of hepatitis B virus (HBV)-associated liver disease, the pro-apoptotic function of HBx protein remains poorly understood. We show that the expression of HBx leads to hyperactivation of caspase-8 and caspase-3 upon treatment with tumor necrosis factor-alpha (TNF-alpha) or anti-Fas antibody, and this activation is correlated with the sensitivity to apoptosis. We demonstrate cytoplasmic co-localization and direct interaction between HBx and the cellular FLICE inhibitory protein (c-FLIP), a key regulator of the death-inducing signaling complex (DISC). Deletion analysis shows that the death effector domain 1 (DED1) of c-FLIP is important for the observed interaction. Overexpression of c-FLIP rescued the cells from HBx-mediated apoptosis, with both the full-length HBV genome and HBx expression vectors. Moreover, c-FLIP and caspase-8 inhibitor considerably protected cells from HBx-mediated apoptosis. These data suggest that HBx abrogates the apoptosis-inhibitory function of c-FLIP and renders the cell hypersensitive towards the TNF-alpha apoptotic signal even below threshold concentration. This provides a novel mechanism for deregulation of hepatic cell growth in HBV patients and a new target for intervention in HBV-associated liver cancer and disease.
 ...
PMID:Pro-apoptotic function of HBV X protein is mediated by interaction with c-FLIP and enhancement of death-inducing signal. 1272 77

Amino acid transporter B(0)/ASC transporter 2 (ATB(0)/ASCT2) is responsible for most glutamine uptake in human hepatoma cells. Because this transporter is not expressed in normal hepatocytes, we hypothesized that its expression is necessary for growth of human liver cancer cells. To test this hypothesis, Sloan Kettering hepatoma (SK-Hep) cells were stably transfected with an inducible 1.3-kb ATB(0)/ASCT2 antisense RNA expression plasmid under the transcriptional control of mifepristone, a synthetic steroid. Induced antisense RNA expression in monolayer cultures decreased ATB(0)/ASCT2 mRNA levels by 73% and glutamine transport rates by 65% compared with controls after 24 h, leading to a 98% decrease in cell number after 48 h. Cellular death was attributable to apoptosis based on cellular blebbing, caspase-3 activation, vital dye and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, and poly-(ADP-ribose) polymerase (PARP) cleavage. Transporter knockdown also markedly increased activities of caspases-2 and -9, marginally enhanced caspase-8 activity, and dramatically increased ASCT1 mRNA levels, presumably as a futile compensatory response. Apoptosis elicited via transporter silencing was not attributable to the double-stranded RNA-dependent protein kinase R (PKR) pathway. For comparison, glutamine deprivation also caused apoptotic cell death but with slower temporal kinetics, stimulated caspases-2 and -3 but not caspases-8 or -9 activities, and led to considerable PARP cleavage. Thus ASCT2 suppression exerts proapoptotic effects transcending those of glutamine starvation alone. We conclude that ATB(0)/ASCT2 expression is necessary for SK-Hep cell growth and viability and suggest that it be further explored as a selective target for human hepatocellular carcinoma.
 ...
PMID:Inducible antisense RNA targeting amino acid transporter ATB0/ASCT2 elicits apoptosis in human hepatoma cells. 1456 74

Interferon (IFN)-alpha directly inhibits proliferation of liver cancer cells by inducing apoptosis, but the molecular mechanisms by which IFN-alpha induces apoptosis in these cells are not fully understood. We examined the effect of broad spectrum caspase inhibitor, Z-VAD-fmk, and the caspase activation in IFN-alpha-mediated apoptosis by using 4 liver cancer cell lines that were sensitive or resistant to IFN-alpha-mediated apoptosis. Involvement of apoptosis-related mitochondrial proteins and Bcl-2 family proteins in IFN-alpha-mediated apoptosis was further examined in 1 sensitive cell line (KIM-1). The Z-VAD-fmk completely or moderately inhibited IFN-alpha-mediated apoptosis in the sensitive cells. IFN-alpha induced time-dependent activation of caspase-3 in the sensitive cells, while the resistant cells showed mild or no activation. Activation of caspase-9, caspase-8, and caspase-7, and the cleavage of poly(ADP-ribose)polymerase were identified in either or both of the sensitive cell lines, but not in the resistant cells. In KIM-1 cells, the release of cytochrome c and Smac/DIABLO from mitochondria to cytosole was confirmed. Meanwhile, Bcl-xL was upregulated, and Bid activation or translocation, or conformational changes of Bax were not identified. In conclusion, our results suggest IFN-alpha-mediated apoptosis in liver cancer cells involves the mitochondrial apoptotic pathway and is induced by activating various caspases.
 ...
PMID:Expression and activation of apoptosis-related molecules involved in interferon-alpha-mediated apoptosis in human liver cancer cells. 1587 Aug 81

Glycyrrhetinic acid (GA) and its related compounds are known to have anti-inflammatory activity and also to inhibit liver carcinogenesis and tumor growth. GA and related compounds inhibited cell proliferation of the human hepatoma cell line, HepG2. Among five compounds tested, ursolic acid and 18beta-olean-12-ene-3beta, 23, 28-triol (18beta-erythrotriol) were comparatively effective, where the 50% inhibitory dose was 20 microM and 25 microM, respectively. Flow-cytometric analysis showed that GA and the related compounds arrested the cell cycle in the G1-phase; in addition, GA-related compounds induced apoptosis at high dose. Western blot analysis indicated that the induction of apoptosis by GA and ursolic acid was accompanied with an activation of caspase-8 and a reduction in the anti-apoptotic proteins, Bcl-2 and Bcl-xL, although the pro-apoptotic proteins, Bax and Bak, remained unaffected. These results suggest that GA and its related compounds may be potent agents in liver cancer treatment.
 ...
PMID:Glycyrrhetinic acid and related compounds induce G1 arrest and apoptosis in human hepatocellular carcinoma HepG2. 1630 97

Hepatocellular carcinoma (HCC), the major manifestation of primary liver cancer, is one of the most frequent and malignant cancers worldwide, especially in Taiwan. Estrogen receptors (ERs) have been reported to play either a proliferation- or apoptosis-enhancing role in the differentiation of cancers, including HCC. In a previous experiment, we showed that transient overexpressed estrogen receptor-alpha induced early stage HCC cell line Hep 3B cell apoptosis by increasing the hTNF-alpha gene expression in a ligand-independent manner. To further clarify if the apoptotic effect occurs in poorly differentiated HCC cell line, HA22T, and elucidate the roles of ERs and TNF-alpha, DNA fragmentation and caspase activity were measured in late stage HCC cell line, HA22T, by measuring the expression of hER-alpha and hER-beta using a Tetracycline-inducible system (Tet-on). Increased DNA fragmentation and caspase-3 activity were found in hERbeta-overexpressed HA22T cells treated with estrogen (10(-8) M) but not in hERalpha-overexpressed HA22T cells. Using RT-PCR/PCR and western blotting in HA22T cells, overexpressed hER-beta was also found to increase the expression of hTNF-alpha mRNA and induce hTNF-alpha-dependent luciferase activity in a ligand-dependent manner. Additionally, LPS treatment and hER-beta overexpression both enhance caspase-8 activities, whereas neither hER-beta nor E2 treatment affected caspase-9 activities. In addition, the overexpressed hER-beta plus E2 enhanced DNA fragmentation and caspase-8 activities were only partially reduced by anti-hTNF-alpha (0.1 ng/ml), which was possibly due to the involvement of P53 and TGF-beta. Taken together, our data indicates that overexpressed hER-beta but not hER-alpha may induce caspase-8-mediated apoptosis by increasing the hTNF-alpha gene expression in a ligand-dependent manner in poorly differentiated HA22T cells.
 ...
PMID:Opposing action of estrogen receptors alpha and beta on tumor necrosis factor-alpha gene expression and caspase-8-mediated apoptotic effects in HA22T cells. 1663 37

Caspase-8 belongs to the cysteine protease family and is known to be activated at the initial step in the cascade of TRAIL-induced apoptosis. The activation of procaspase-8 can be blocked by a relatively large amount of c-FLIP, which renders resistance to death receptor-mediated apoptosis in many types of cancer cells. To ask if extrinsic over-expression of caspase-8 contributes to the induction of apoptosis, we introduced the caspase-8 gene into HCC cells using an adenoviral (Adv) vector (Adv-Casp8). We demonstrated that Adv-Casp8 increased expression of active forms of caspase-8 in MOI-dependent manner. A large amount of Adv-Casp8 (MOI of 50) induced apoptosis significantly in HCC cells and resulted in downregulation of c-FLIP (in SK-Hep1, HLE, and HepG2 cells), XIAP, survivin, and Bcl-xL (in HLE cells) and dynamic release of cytochrome c and Smac from the mitochondria into the cytosol. On the other hand, a small amount of Adv-Casp8 (MOI of 10) causes a slight but detectable increase in the level of apoptosis with only a small effect on anti-apoptotic proteins and mitochondrial activation. However, small amounts of Adv-Casp8 augmented TRAIL- or chemotherapeutic agent-induced cell death (with an MOI of 10 or 20, respectively). These results suggest both that exogenous over-expression of caspase-8 by Adv-Casp8 may be essential for induction of HCC cell death and that the combination of Adv-Casp8 and TRAIL or chemotherapeutic agents could provide a useful strategy for treatment of HCC.
 ...
PMID:Adenovirus-mediated transfection of caspase-8 sensitizes hepatocellular carcinoma to TRAIL- and chemotherapeutic agent-induced cell death. 1675 Feb 75

Histone deacetylase (HDAC) inhibitors represent a promising group of anticancer agents. This paper shows that the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) stimulated at 5-10 microM apoptosis in human hepatoma HepG2 and Huh6 cells, but was ineffective in primary human hepatocytes (PHH). In HepG2 cells SAHA induced the extrinsic apoptotic pathway, increasing the expression of both FasL and FasL receptor and causing the activation of caspase-8. Moreover, SAHA enhanced the level of Bim proteins, stimulated alternative splicing of the Bcl-X transcript with the expression of the proapoptotic Bcl-Xs isoform, induced degradation of Bid into the apoptotic factor t-Bid and dephosphorylation and inactivation of the anti-apoptotic factor Akt. Consequently, SAHA caused loss of mitochondrial transmembrane potential, release of cytochrome c from mitochondria, activation of caspase-3 and degradation of PARP. Interestingly, a combination of suboptimal doses of SAHA (1 microM) and bortezomib (5-10 nM), a potent inhibitor of 26S proteasome, synergistically induced apoptosis in both HepG2 and Huh6 cells, but was ineffective in PHH. Combined treatment increased with synergistic effects the expression levels of c-Jun, phospho-c-Jun and FasL and the production of Bcl-Xs. These effects were accompanied by activation of Bid, caspase-8 and 3. In conclusion, SAHA stimulated apoptosis in hepatoma cells and exerted a synergistic apoptotic effect when combined with bortezomib. In contrast, these treatments were quite ineffective in inducing apoptosis in PHH. Thus, our results suggest the potential application of the SAHA/bortezomib combination in clinical trials for liver cancer.
 ...
PMID:SAHA induces apoptosis in hepatoma cells and synergistically interacts with the proteasome inhibitor Bortezomib. 1735 39


1 2 3 4 5 6 7 8 Next >>