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)

Hepatocellular carcinoma (HCC) is highly malignant and prone to multicentric occurrence. Differentiation between a true relapse of HCC and a second primary tumour appearing is of clinical importance. At this point, no convenient method is available to determine the origin of these HCCs. Tissue samples were obtained from 19 patients and analysed for the promoter hypermethylation status of multiple tumour suppressor genes (p16, DAP-Kinase, MGMT, GSTP1, APC, RIZ1, SFRP1, SFRP2, SFRP5, RUNX3, and SOCS1) using methylation-specific PCR (MSP). Methylation status was used to determine tumour clonality. In each of the 19 cases, at least one tumour was recognised as having an aberrantly methylated gene. The frequency of the methylation in tumour tissue was 57.1% in p16, 2.4% in DAP-kinase, 23.8% in GSTP1, 90.5% in APC, 45.2% in RIZ1, 64.3% in SFRP1, 59.5% in SFRP2, 28.6% in SFRP5, 47.6% in RUNX3, and 54.8% in SOCS1, while in MGMT, no aberrant methylation was detected. The methylation status of these genes was assessed using MSP as being either positive or negative, and was used to determine the tumour clonality. The clonality of every tumour could be decided even with lesions that could not be judged by clinical diagnosis or by another molecular method (mt DNA mutation). Determining the methylation status of multiple genes in multicentric HCC was useful as a clonal marker and provided useful information for characterising the tumour. From our findings, multicentric HCCs tend to occur more independently than metastatically from the original tumour. Expanded study should be pursued further for a better understanding of the molecular mechanism of hepatocarcinogenesis.
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PMID:Hypermethylation of multiple genes as clonal markers in multicentric hepatocellular carcinoma. 1796 29

Activation of the extracellular signal-regulated kinase (ERK) pathway is a key factor in the regulation of cell proliferation by growth factors. Hepatocyte growth factor (HGF)-induced cell cycle arrest in the human hepatocellular carcinoma cell line HepG2 requires strong activation of the ERK pathway. In this study, we investigated the molecular mechanism of the activation. We constructed a chimeric receptor composed of the extracellular domain of the NGF receptor and the cytoplasmic domain of the HGF receptor (c-Met) and introduced a point mutation (N1358H) into the chimeric receptor, which specifically abrogates the direct binding of Grb2 to c-Met. The mutant chimeric receptor failed to mediate the strong activation of ERK, up-regulation of the expression of a Cdk inhibitor p16(INK4a) and inhibition of HepG2 cell proliferation by ligand stimulation. Moreover, the mutant receptor did not induce tyrosine phosphorylation of the docking protein Gab1. Knockdown of Gab1 using siRNA suppressed the HGF-induced strong activation of ERK and inhibition of HepG2 cell proliferation. These results suggest that coupling of Grb2 to Gab1 mediates the HGF-induced strong activation of the ERK pathway, which is required for the inhibition of HepG2 cell proliferation.
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PMID:Coupling of Grb2 to Gab1 mediates hepatocyte growth factor-induced high intensity ERK signal required for inhibition of HepG2 hepatoma cell proliferation. 1800 5

Strong activation of the ERK signal is required for hepatocyte growth factor (HGF) to inhibit proliferation of the human hepatocellular carcinoma cell line HepG2. However, it is still to be elucidated whether the activation alone is sufficient to induce the inhibitory effect. In this study, we constructed HepG2 cell clones expressing a high level of epidermal growth factor receptor (EGFR), and examined the effect of the strong activation of ERK on the proliferation of the cell clones. EGF treatment of the cell clones induced strong activation of ERK similar to HGF treatment, but did not inhibit cell proliferation. HGF treatment of the cell clones up-regulated the expression of a Cdk inhibitor p16(INK4a), which has previously been shown to be required to inhibit the proliferation of HepG2 cells, but EGF treatment did not. Furthermore, EGF treatment of the cell clones did not induce the up-regulation of another Cdk inhibitor p21(CIP1), whereas HGF treatment did. Knockdown of p21 by siRNA restored the proliferation of HepG2 cells inhibited by HGF, and restored Cdk2 activity suppressed in HGF-treated HepG2 cells. These results suggest that strong activation of ERK alone is not sufficient, and some other pathway(s), which is activated through the HGF receptor but not through EGFR, is also required to induce the up-regulation of p16 and p21 expression, and also suggest that in addition to the up-regulated expression of p16, that of p21 contributes to the suppression of Cdk2 activity leading to the inhibition of proliferation of HGF-treated HepG2 cells.
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PMID:Up-regulation of p21CIP1 expression mediated by ERK-dependent and -independent pathways contributes to hepatocyte growth factor-induced inhibition of HepG2 hepatoma cell proliferation. 1800 40

Hepatocellular carcinoma (HCC) is a frequent neoplasia which still misses a therapeutical gold standard. Recently, new acquisitions in cancerogenesis process evidenced the genetic and epigenetic alterations of genes involved in the different metabolic pathways of liver cancer suggesting that antibodies, small molecules, demethylating agents, etc. specifically acting against molecular target can be utilized alone or in combination in clinical practice. The main altered targets are: cell membrane receptors, in particular tyrosine kinase receptors, factors involved in cell signalling, specifically Wnt/beta-catenin, Ras/Raf/MEK/ERK and PI3K/Akt/mTOR pathways, proteins linked to cell cycle regulation pathway (i.e. p53, p16/INK4, cyclin/cdk complex) or in invasiveness (EMT, TGFbeta) and proteins involved in DNA metabolism. Genetic or epigenetic changes in these molecules have been used in preclinical settings and, some of them also in clinical trials of phase II and III. This scenario opens new avenues for the prevention and the treatment of HCC. In the present review the main metabolic pathways and molecular alterations have been described together with recent advances in molecular and gene therapy.
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PMID:Molecular pathways and related target therapies in liver carcinoma. 1804 79

Telomere shortening limits the proliferative capacity of human cells, restrains the regenerative capacity of organ systems during chronic diseases and aging and also induces chromosomal instability as well as initiation of cancer. Previous studies demonstrated that telomeres are often significantly shorter in tumor tissue, including hepatocellular carcinoma (HCC), compared to the surrounding tissue, but telomere length in HCC tissues was not correlated with several clinical parameters, such as age, sex, HBV or HCV infections and tumor size. In the present study, the telomere length ratio of 36 paired HCC, and their adjacent non-tumor tissues was measured by quantitative PCR (Q-PCR). The mean telomere lengths (SD) for HCC and adjacent non-tumor tissues were 0.26 (0.10) and 0.47 (0.20) respectively (t = 6.22, P < 0.0001). There was a large difference in the distribution of subjects based on telomere length in tumor and adjacent non-tumor tissues. The number of tumors with telomere length shorter than 0.50 was much higher than that of adjacent non-tumor tissues; more than 90% of the tissues with telomere length > or = 0.50 were adjacent non-tumor tissues. The correlations between telomere length and aflatoxin B1- and polycyclic aromatic hydrocarbon-DNA adducts level, p53 mutations and p16 hypermethylation status were also tested, but no significant associations were found. The relationship between telomere length shortening, chemical carcinogen exposure, and genetic and epigenetic changes in hepatocarcinogenesis needs further investigation.
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PMID:Telomere length in hepatocellular carcinoma and paired adjacent non-tumor tissues by quantitative PCR. 1879 66

Hepatocellular carcinoma (HCC) is one of the most common human cancers, and its incidence is still increasing in many countries. The prognosis of HCC patients remains poor, and identification of useful molecular prognostic markers is required. Many recent studies have shown that functional alterations of cell-cycle regulators can be observed in HCC. Among the various types of cell-cycle regulators, p16 and p27 are frequently inactivated in HCC and are considered to be potent tumor suppressors. p16, a G1-specific cell-cycle inhibitor that prevents the association of cyclindependent kinase (CDK) 4 and CDK6 with cyclin D1, is frequently inactivated in HCC via CpG methylation of its promoter region. p16 may be involved in the early steps of hepatocarcinogenesis, since p16 gene methylation has been detected in subsets of pre-neoplastic liver cirrhosis patients. p27, a negative regulator of the G1-S phase transition through inhibition of the kinase activities of Cdk2/cyclin A and Cdk2/cyclin E complexes, is now considered to be an adverse prognostic factor in HCC. In some cases of HCC with increased cell proliferation, p27 is overexpressed but inactivated by sequestration into cyclin D1-CDK4-containing complexes. Since loss of p16 is closely related to functional inactivation of p27 in HCC, investigating both p16 and p27 may be useful for precise prognostic predictions in individuals with HCC.
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PMID:Molecular mechanism underlying the functional loss of cyclindependent kinase inhibitors p16 and p27 in hepatocellular carcinoma. 1835 Jun 4

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Little is known about its molecular pathogenesis and the relevance of DNA methylation for disease initiation and progression. Nevertheless, promoter methylation of some genes has been implicated as potential marker for HCC. Thirty-four HCC, 34 matching non-malignant, cirrhotic livers and 16 normal livers were analyzed for the methylation status of the genes p16(INK4a), GSTP1, MGMT, DAP-K and APC by quantitative methylation-specific PCR. DNA promoter methylation frequencies in HCC and matching non-malignant cirrhotic liver, respectively, were as follows: p16(INK4a) (76% vs. 24%), GSTP1 (53% vs. 32%), MGMT (6 vs. 12%), DAP-K (68 vs. 100%) and APC (100 vs. 100%). GSTP1 and/or p16(INK4a) promoter methylation was observed in 88% of the HCC samples. In normal liver tissue, the p16(INK4a), GSTP1 and MGMT promoter were not methylated. DAP-K was methylated in 31% and APC even in 100% of normal liver samples. Quantitative levels of methylated promoter DNA of all genes were significantly different in the various tissue types except for MGMT. Our results suggest that promoter methylation of tumor-associated genes is a common event in hepatocarcinogenesis. Significantly, higher levels and frequencies of promoter methylation in HCC were found for p16(INK4a) and GSTP1 compared to non-malignant cirrhotic liver. This indicates that these epigenetic events may serve as a good marker for HCC. These data also demonstrate the importance of the quantification of methylated promoter DNA within a given sample and the use of normal tissue as controls. Quantitative analyses of methylated GSTP1 and p16(INK4a) promoter may serve as a powerful molecular marker in detecting HCC in biopsies.
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PMID:Quantitative promoter methylation analysis of hepatocellular carcinoma, cirrhotic and normal liver. 1835 80

Genomic instability during hepatocarcinogenesis causes changes in signal transduction network. Strategies for identification of new markers/therapeutic targets include discovery of early molecular changes during hepatocarcinogenesis, relevant to preneoplastic lesions progression to full malignancy in rodent models, and evaluation of these changes in human hepatocellular carcinomas (HCCs). Activation of ERB receptor family, MAPK, JAK-STAT, beta-Catenin cascades, c-Myc targets, iNOS-IKK/MAT1A-NF-kB axis, Ornithine decarboxylase, Cyclins and CDKs occurs in human and rodent hepatocarcinogenesis. This is associated with downregulation of the cell cycle inhibitors p16(INK4A) and p53 and TGF-beta/SMAD signaling. Oncosuppressor genes, including p16(INK4A), E-CAD, and DLC-1 are often hypermethylated in humans and rodents. Moreover, protection of cell cycle from p16(INK4A) inhibition by upregulation of CDC37, HSP90, and CRM1 correlates to HCC progression. A body of evidence indicates that inhibition of key genes of aforementioned signaling pathways by antisense or siRNA approaches or specific inhibitors restraints growth of in vitro cultured or in vivo xenografted HCCs. Efforts are currently dedicated to improve transduction efficiency. HCC cells may escape gene therapy by various mechanisms. Attempts to overcome this difficulty include discovery of new therapeutic targets, gene therapy directed to different molecular targets essential for tumor cell survival and specifically directed to HCC subtypes.
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PMID:Dissection of signal transduction pathways as a tool for the development of targeted therapies of hepatocellular carcinoma. 1847 8

Despite significant advances in the detection and treatment of hepatocellular carcinoma, the prognosis of patients with hepatocellular carcinoma remains very poor, in part due to the high incidence of recurrence. This study was aimed at identifying a prognostic indicator of recurrence in patients with hepatocellular carcinoma. We retrospectively analyzed CpG island hypermethylation of the p14, p15, p16, GSTP1, integrin alpha4, SYK, and CDH1 genes in fresh-frozen tissues from 265 patients with hepatocellular carcinoma using the methylation-specific PCR. The expression levels of p16 and p53 were evaluated by immunohistochemistry. CpG island hypermethylation was detected in 6% for p14, 21% for p15, 67% for p16, 75% for GSTP1, 23% for integrin alpha4, 12% for SYK, and 57% for CDH1. Recurrence was observed in 102 (38%) of the 265 patients. There was no association between the risk for recurrence and hypermethylation of any gene studied. However, p16 methylation was associated with a poor survival after surgery for recurrent stage I to II hepatocellular carcinomas (hazard ratio, 4.05; 95% confidence interval, 1.15-14.20; P = 0.03). In addition, the hazard of failure after recurrence was about 3.80 (95% confidence interval, 1.03-14.20; P = 0.04) times higher in patients with p16 methylation than in those without. Negative expression of p16 at a protein level was also associated with poor survival in recurrent stage I to II hepatocellular carcinomas, but p53 expression did not have a synergistic effect on the poor prognosis. In conclusion, the present study suggests that p16 methylation may be associated with a poor prognosis in recurrent early-stage hepatocellular carcinomas.
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PMID:Promoter hypermethylation of the p16 gene is associated with poor prognosis in recurrent early-stage hepatocellular carcinoma. 1872 30

Hepatocellular carcinoma (HCC) constitutes the 5th most frequent cancer worldwide, and due to a lack of treatment options, HCC represents the 3rd most lethal cancer worldwide. The incidence of HCC is continuously rising in Europe and Northern America, which can be explained by spreading of hepatitis C virus infections. Systemic chemotherapy is not an option for most patients with HCC. The most promising strategy for systemic treatment of HCC is targeted therapy. Successful targeted therapy has to inhibit pathways which are necessary for tumor growth, even in the late stages of carcinogenesis. The p16/Rb, p53, and IGF2R checkpoints as well as oncogenic alterations of telomerase, c-myc, Wnt/beta-catenin, PI3K/Akt, hedgehog, and c-met/HGF are most frequently involved in human hepatocarcinogenesis. However, currently, the most attractive target for molecular therapy of HCC appears to be the vascular endothelial growth factor (VEGF). Phase I/II studies showed high progression-free survival rates with antibodies or small molecules targeting the VEGF receptor pathway. Recently, a randomized placebo-controlled phase III study showed that the multikinase inhibitor sorafenib, which inhibits VEGF and Raf, significantly improves survival of patients with advanced HCC and Child A cirrhosis. As a consequence of this study, sorafenib is now the first available drug for effective systemic treatment of patients with advanced HCC.
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PMID:Molecular pathogenesis and targeted therapy of hepatocellular carcinoma. 1885 56


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