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

Mitotic cyclins constitute a regulatory subunit of the histone H1 kinase complex. On the ground of their primary structure they are divided into two classes A and B, both necessary for the mitosis. Cyclin A activates histone H1 kinase and becomes destroyed by proteolysis earlier than cyclines B and plays an important role in the DNA replication. Cyclins A and B may be involved in the development of neoplastic disorders either directly (inappropriate expression of the cyclin A gene caused by hepatitis B virus in hepatocellular carcinoma, or interactions of this cyclin with factors participating in the regulation of cell proliferation) or indirectly by phosphorylation of some oncogene or antioncogene proteins by a cdk (cyclin dependent kinase).
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PMID:[Mitotic cyclins--new possibilities for examining mechanisms of neoplasm growth]. 823 85

The mammalian cell cycle is controlled by regulators of the G1 to S transition such as tumor suppressor proteins, p53 and retinoblastoma (RB); cyclin D1 and cyclin-dependent kinase 4; and inhibitor of cyclin dependent kinase, p16INK4A. Recently, aberrations of these cell cycle-related genes have been reported to contribute to the formation and development of cancer. In human hepatocellular carcinoma (HCC), high frequencies of aberration have been detected in the p53 and RB genes. Loss of heterozygosity (LOH) of chromosome 13q was detected in 35% of HCC and LOH on chromosome 17p was detected in 49%. Mutation of the p53 gene was also detected in 32%. The aberrations of these genes were observed more frequently in poorly differentiated and in advanced HCCs. On the other hand, genetic alterations of the cyclin D1 and p16INK4A genes were not so frequent, but appeared to be associated with the aggressive behavior of the tumor, which suggests that disruption of the cell cycle-related genes results in the progression of HCC. Further study with a substantial number of cases is required to determine the actual frequency of the aberrations of the G1 controlling genes in hepatocarcinogenesis.
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PMID:Alteration of cell cycle-related genes in hepatocarcinogenesis. 930 64

In the Solt-Faber model DENA and 2-Acetaminofluorene (AAF) treatment combined with hepatectomy induces hepatocellular carcinoma in rats. In this model AAF blocks proliferation of hepatocytes, while oval cells restore liver mass. Here we studied the molecular mechanism involved in blocking AAF-dependent cell cycle progression of hepatocytes. AAF inhibits cell proliferation of hepatocytes shown by the lack of Cyclin E expression before the G1/S phase restriction point. Immunfluorescence studies revealed that Cyclin E positive signals were restricted to oval cells, while hepatocytes remained negative. Additionally, AAF treatment induces strong nuclear p53 expression which is associated with increased p21 mRNA levels. Inhibition of active Cyclin/CdK (cyclin dependent kinase) complexes is reflected in AAF-treated animals by decreased RB expression and phosphorylation. The decrease in RB expression and phosphorylation, which is essential in triggering DNA synthesis and Cyclin A expression, leads to a deficiency in transcriptionally active E2F complex formation after hepatectomy. Thus, two molecular explanations are evident to account for AAF-dependent cell cycle progression of hepatocytes in vivo: first, induction of p53 expression which leads to higher p21 mRNA levels, and second, a lack of Cyclin E expression at the G1/S phase restriction point after hepatectomy.
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PMID:2-acetaminofluorene blocks cell cycle progression after hepatectomy by p21 induction and lack of cyclin E expression. 1059 46

Increasing evidence has indicated that perturbation of cyclins is one of the major factors leading to cancer. The aim of this study was not only to investigate various cell cycle-related kinase activities in hepatocellular carcinoma (HCC), but also to analyze the difference of cell cycle-related kinase activity levels between hepatitis C virus (HCV)-induced HCC and HCV-induced cirrhosis. The protein levels of cyclins D1, E, A, and H, and of cyclin dependent kinase 1 (Cdk1), Cdk2, Cdk4, Cdk6, and Cdk7 in HCC and in surrounding nontumorous cirrhosis were determined by Western blot. The enzymatic activities of cyclins D1, E, A, Cdk1, Cdk4, Cdk6, Cdk7, and Wee1 were measured using in vitro kinase assays. Protein levels and kinase activities of cyclin D1, Cdk4, cyclin E, cyclin A, and Wee1 were significantly elevated in HCC compared with surrounding cirrhotic tissues. The enhanced cyclin D1-related kinase activity in HCC was accompanied by the up-regulation of Cdk4 activity, but not Cdk6 activity. The kinase activities of Cdk6, Cdk7, and Cdk1 did not differ between HCC and surrounding cirrhotic tissues. In addition, the protein levels and kinase activities of cyclin D1, Cdk4, and cyclin E were higher in poorly differentiated HCC and advanced HCC. In conclusion, the increases of cyclin D1, Cdk4, cyclin E, cyclin A, and Wee1 play an important role in the development of HCC from cirrhosis. Cyclin D1, Cdk4, and cyclin E activation may be closely related to the histopathologic grade and progression of HCC.
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PMID:Cyclins and cyclin-dependent kinases: comparative study of hepatocellular carcinoma versus cirrhosis. 1260 50

Expression of cyclin dependent kinase (Cdk) inhibitor p27(Kip1), which blocks cell cycle progression from G(1) to S phase, can be regulated via multiple mechanisms including transcription, protein degradation, and translation. Recently, it was shown that p27(Kip1) plays an important role in the cellular response to hypoxia. However, the mechanisms involved in the hypoxia-induced regulation of p27(Kip1) expression are still not clear. In this study, we compare the expression of p27(Kip1) in two related murine hepatoma cell lines, Hepa-1 and c4. Hepa-1 produces functional aryl hydrocarbon receptor nuclear translocator (ARNT). c4 cells are derived from Hepa-1, but are ARNT deficient. Interestingly, we observed cell line-dependent effects of hypoxia on the expression of p27(Kip1). The level of p27(Kip1) protein in Hepa-1 cells is enhanced by hypoxia, but is reduced by hypoxia in c4 cells. Further investigation demonstrated that hypoxia-induced, ARNT-mediated, transactivation of the p27(Kip1) gene in Hepa-1 cells is responsible for the increase in p27(Kip1) protein. Once c4 cells were stably transfected with the wild type ARNT gene, a hypoxia-induced increase in p27(Kip1) mRNA was observed and reduction of p27(Kip1) protein caused by hypoxia was blocked. Hence, our data indicate that ARNT is involved in transcriptional upregulation of the p27(Kip1) gene under hypoxic conditions.
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PMID:Cyclin dependent kinase inhibitor p27(Kip1) is upregulated by hypoxia via an ARNT dependent pathway. 1452 89

It is thought that the subcellular distribution of Src-family tyrosine kinases, including c-Yes binding to the cellular membrane, is membranous and/or cytoplasmic. c-Yes protein tyrosine kinase is known to be related to malignant transformation. However, the expression patterns of c-Yes in hepatocellular carcinoma (HCC) remains unknown. In the present study, we report that c-Yes is expressed not only in the membrane and cytoplasm, but also in the nuclei of cancer cells in some human HCC tissues and in a human HCC cell line. We examined the expression and localization of c-Yes in human HCC cell lines (HLE, HLF, PLC/PRF/5 and Hep 3B) by Western blotting and immunohistochemical analyses; we also examined the expression of c-Yes by immunohistochemistry and Western blotting in the tissues of various liver diseases, including 39 samples from HCC patients. We used an antibody array to detect proteins that bind to nuclear c-Yes in PLC/PRF/5 cell line. c-Yes was found to be expressed in the membranes and cytoplasm of HLE, HLF and Hep 3B HCC cells; it was also detected in the nuclei in addition to the membranes and cytoplasm of PLC/PRF/5 HCC cells. HCC with nuclear c-Yes was detected in 5 of 39 cases (13.0%), and nuclear c-Yes expression was not detected in normal, chronic hepatitis or cirrhotic livers. All HCCs with nuclear c-Yes expression were well-differentiated, small tumors at the early stages. In the PLC/PRF/5 cell line, the nuclear localization of c-Yes with cyclin-dependent kinase 1 was confirmed by a protein antibody array. In conclusion, nuclear c-Yes expression was found in cancer cells at the early stages of hepatocarcinogenesis, suggesting that nucleus-located c-Yes may be a useful marker to detect early-stage HCC.
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PMID:Identification of c-Yes expression in the nuclei of hepatocellular carcinoma cells: involvement in the early stages of hepatocarcinogenesis. 1714 18

To clarify hepatocarcinogenesis by the heterocyclic amine, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), we investigated the global expression of genes in rat liver. Rats were continuously fed MeIQx 100 ppm in their diet, and were sacrificed at weeks 4 and 16 for early time points, and week 104 for tumor sampling. Global expression analysis using oligonucleotide microarrays (Affimetrix Gene Chip, Rat Genome 230 2.0 Array) was carried out to detect altered genes in MeIQx-treated liver at 4 and 16 weeks (n=5, each), MeIQx-induced hepatocellular adenomas (HCA; n=3), and hepatocellular carcinomas (HCC; n=3), compared with age-matched normal livers (n=5). To investigate functional networks and gene ontology, two clusters were analyzed by Ingenuity Pathway Analysis. Clustering analysis of global genes demonstrated gene profiles of HCA and HCC to greatly differ from those of age-matched normal liver. However, after treatment with MeIQx for 4 or 16 weeks, no major differences were apparent. Ingenuity Pathway Analysis suggested pathways related to the cell cycle and glutathione metabolism may be involved in MeIQx-induced hepatocarcinogenesis. Real-time PCR analysis confirmed elevation of cyclin B1, cell division cycle 2, glutathione peroxidase 2 and glutathione S-transferase A2 in tumors, but not in early stage livers. In conclusion, molecular signatures of MeIQx-induced tumors clearly vary from that of age-matched normal liver, but no such shift is evident at early stages of hepatocarcinogenesis.
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PMID:Analysis of gene expression in different stages of MeIQx-induced rat hepatocarcinogenesis. 1734 10

A newly synthesized dithiocarbamate derivative, 4-methylpiperazine-1-carbodithioc-acid-3-cyano-3,3-diphenylpropyl ester hydrochloride (TM208), has demonstrated anticancer effects with low toxicity in earlier studies; however, the mechanism has yet to be identified. We explored antitumor effects of TM208 and the possible mechanisms by which it inhibited the growth of human hepatocellular carcinoma cell line QGY-7703 xenograft tumors. Cell proliferation was evaluated with the sulforhodamine B assay in vitro. The results suggested that TM208 had slightly antiproliferative activity on QGY-7703 cells. The antitumor effect of TM208 was assessed in nude mice xenografted with QGY-7703 tumors. We found that TM208 significantly inhibited tumor growth but did not cause loss of body weight or leukocytopenia. Western blotting was used to detect the expression of protein kinase C alpha, mitogen-activated protein kinase signal pathways, and cell cycle-related proteins. The results showed that TM208 decreased the expression of protein kinase C alpha, phospho-extracellular signal-regulated kinase-1/2, phospho-p38, cyclin B1, cell division cycle 2 (cdc2), and phospho-cdc2 (Thr161) and increased the expression of phospho-cdc2 (Tyr15). Taken together, our data show that TM208 has little antiproliferative effect on QGY-7703 cells in vitro, whereas it significantly inhibits the growth of QGY-7703 xenograft tumors with low toxicity in vivo. The inhibition of mitogen-activated protein kinase signal pathways and the regulation of the G2/M phase may be responsible for its antitumor effects.
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PMID:Effect of TM208 on QGY-7703 xenograft tumor growth. 1852 18

Diacetyldianhydrogalactitol (DADAG) is a member of the hexitols which shows a significant anticancer effect. Despite the fact that the antitumor effects of DADAG have been studied in a number of cell lines, the mechanism of its action remains unclear. Herein, we explored antitumor effects of DADAG and the possible mechanisms by which it inhibited the growth of human hepatocellular carcinoma cell QGY-7,703 and its derived xenograft tumors. Cell proliferation was evaluated with the sulforhodamine B assay in vitro. The results suggested that DADAG had mild antiproliferative activity on QGY-7,703 cells. The antitumor effect of DADAG was assessed in nude mice xenografted with QGY-7,703 cells. We found that DADAG significantly inhibited the tumor growth. Flow cytometry results indicated that the retarded cell proliferation is associated with increased G2/M cell cycle arrest. Further studies showed that the induced G2/M cell cycle arrest is, at least partially, attributed to an upregulation of cyclin B1, phospho-cell division cycle 2 (cdc2) (Thr), phospho-cdc2 (Thr), and cdc25c protein expression, and a decrease in cdc2 protein expression. Taken together, our data show that DADAG has mild proliferative effects on QGY-7,703 cells in vitro, but it significantly inhibits the growth of QGY-7,703 in a xenograft model in vivo. The modulation of several cell cycle progression regulation proteins responsible for G2/M phase transition may account for its antitumor effects.
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PMID:Anticancer activity and mechanisms of diacetyldianhydrogalactitol on hepatoma QGY-7703 cells. 1974 3

The aim of this study was to determine whether caffeine enhanced radiosensitization in an orthotopic transplant of LM3 human hepatocellular cancer in nude mice. LM3 hepatocellular carcinoma cells were infected with red fluorescent protein and irradiated, and cell cycle distribution and survival fraction were detected. A nude mouse model of orthotopic transplant of red fluorescent protein-expressing LM3 hepatocellular cancer was established. Nude mice were divided into four groups: control (NS); caffeine (Caff) alone; irradiation (IR) alone; and caffeine + IR (Caff + IR). Tumor growth curves were described. Expression of cyclin and apoptosis were evaluated by analysis of phosphorylated cyclin dependent kinase 1 (CDC2) Tyr15 (CDC2-Tyr15-P), cyclinB1, TUNEL staining, and caspase-3. Caffeine abrogated IR-induced G(2) phase arrest and decreased survival of irradiated LM3 cells. Caffeine enhanced radiosensitivity of LM3 hepatocellular cancer in vivo. Tumor growth delay time in the Caff + IR group was 14.3 days compared with the NS group, 14.1 days compared with the Caff alone group, and 7.2 days compared with the IR alone group. At 15 Gy, expression of CDC2-Tyr15-P in the Caff + IR group (26.0 +/- 8.9%) was significantly lower than in the IR alone group (68.4 +/- 10.6%), expression of cyclinB1 and proportion of TUNEL-positive cells in the Caff + IR group (30.4 +/- 8.7% and 59.2 +/- 9.5%, respectively) was significantly higher than in the IR alone group (7.0 +/- 3.7% and 24.2 +/- 7.2%, respectively), expression of caspase-3 was consistent with the TUNEL staining results. This study suggested that caffeine might enhance the radiosensitivity of LM3 hepatocellular cancer in vivo, and may be feasible for further clinical applications.
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PMID:Caffeine enhances radiosensitization to orthotopic transplant LM3 hepatocellular carcinoma in vivo. 2038 27


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