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)

Prolinedithiocarbamate (PDTC) and diethyldithiocarbamate (DDTC) are cancer chemopreventive agents and can be biotransformed to prolinethiuramdisulfide (PTDS) and tetraethylthiuramdisulfide (disulfiram; DTDS), respectively. We found that the reactive metabolites PTDS and DTDS induced apoptosis after G1/S arrest. Phosphorylation of cyclin E, inhibition of cyclin-dependent kinase 2 activity, and degradation of cyclin E were found in human hepatoma Hep G2 cells during apoptosis. Moreover, PTDS and DTDS decreased the level of bcl-2 but increased the level of p53. In contrast, PDTC, DDTC, and ammonium dithiocarbamate (ADTC) did not induce apoptosis; rather they led to the induction of p53 and p21 followed by G1/S arrest. PDTC, DDTC, and ADTC also arrested cells in G1 phase. We then examined the effects of PTDS and DTDS on the signal transduction mechanisms leading to apoptosis. Although the transcription factors NFkappaB and AP-1 cooperatively decreased their DNA-binding activities to kappaB and 12-O-tetradecanoylphorbol-13-acetate-responsive elements, respectively, and p53 increased DNA-binding activity in the early stage but decreased it in the latter stage after treatment with PTDS, when the human Hep G2 cells were undergoing apoptosis. In summary, our results indicated that (i) PTDS and DTDS induced apoptosis and G1/S arrest mediated by p53, whereas PDTC, DDTC, and ADTC induced p53-dependent p21 expression leading to G1/S arrest; (ii) PDTC, DDTC, and ADTC induced p21/KIP1/CIP1 expression in a p53-dependent pathway leading to G1/S arrest; and (iii) NFkappaB, AP-1, and bcl-2 were downregulated during PTDS- and DTDS-induced apoptosis. These results suggested that PTDS and DTDS induced p53-dependent apoptosis, whereas PDTC, DDTC, and ADTC induced G1/S arrest. Apoptosis is regulated by the modulation of intracellular effectors such as NFkappaB, AP-1, and bcl-2 and activation of p53 in early stages.
 ...
PMID:Induction of apoptosis by thiuramdisulfides, the reactive metabolites of dithiocarbamates, through coordinative modulation of NFkappaB, c-fos/c-jun, and p53 proteins. 972 16

In the development of a cancer, unlimited cell proliferation has been believed to play an important role. In addition, a programmed cell death called apoptosis, which is regulated by several oncogenes and tumor suppressor genes, has been suggested to be another important different pathway of carcinogenesis. Recently, several reports on cell proliferation capacity and apoptosis in the development of human liver disease have been published, but the cell proliferation index and its relationship between the expression of the bcl-2 and p53 genes involving apoptosis has not yet been discussed in view of the clinical differences of primary and metastatic liver cancer. In this study, we investigated the cell proliferation index and expression of p53 and bcl-2 in the tumorous and non-tumorous portions of both hepatocellular carcinoma and metastatic liver cancer. The expression of p53 was observed in both hepatocellular carcinoma and metastatic liver cancer, but bcl-2 expression was observed neither in hepatocellular carcinoma nor in metastatic liver cancer. In hepatocellular carcinoma, the p53 positive group showed a higher Ki-67 score (cell proliferation index) and more tumor numbers than the p53 negative group (p < 0.05). In metastatic liver cancer, the results were the same as in hepatocellular carcinoma (p < 0.05). However, we could not correlate the p53 expression and its prognostic significance in hepatocellular carcinoma.
 ...
PMID:Cell proliferation index and the expression of p53 and Bcl-2 in tumorous and non-tumorous lesions of hepatocellular carcinoma and metastatic liver cancer. 982 91

Patients with hepatitis C have an increased risk of developing hepatocellular carcinoma (HCC). This is related to the stage of chronic liver disease, as characterized histologically by hepatic fibrosis and architectural distortion, but it is unclear whether histological markers can define the risk of developing HCC. We conducted a case-control immunohistochemical study of Ki-67, a marker for hepatocellular proliferation, in livers of 18 patients who had developed HCC more than 2 years after the biopsy specimen had been taken. Using conditional logistic regression analysis, the results were compared with 18 selected controls, who were age-matched patients with hepatitis C of similar histological stage who had not developed HCC. We also examined livers for cellular dysplasia, p53 mutations, and bcl-2 overexpression, and assessed whether the results could be correlated with demographic and disease-related variables, such as gender, region of birth, alcohol consumption, severity of liver disease, HCV genotype, and markers of hepatitis B virus (HBV) infection. Livers from patients who developed HCC were more often positive for Ki-67 (13 of 18 [72%] v 9 of 18 [50%]; P = .06) and tended to have higher mean Ki-67 scores (6 +/- 7.5 v 3 +/- 4.4; P = .10) compared with control cases. In the HCC-predisposed group, three livers showed large cell dysplasia, two were positive for p53 mutations, and two for bcl-2 overexpression. In contrast, in the non-HCC group, only one case had dysplasia, and none were positive for immunostaining for p53 or bcl-2 mutations. With the exception of one case, all livers with large cell dysplasia or p53 mutations and bcl-2 overexpression were also positive for Ki-67. Twelve (55%) of the 22 Ki-67-positive cases were anti-HBc-positive in the serum, in contrast to 2 of 14 (14%) patients in the Ki-67-negative group (P = .01). Patients with evidence of past infection with HBV were more often Ki-67 positive than those who had no evidence of past infection (85% [11 of 13] v 45% [10 of 22]; P = .02). There were no other associations between demographic or disease-related variables and Ki-67 expression. Increased hepatocellular proliferative activity, as assessed by Ki-67 expression, may be one factor indicative of an increased risk of developing HCC among patients with chronic hepatitis C. Furthermore, past infection with HBV appears to be an important correlate of increased hepatocellular proliferation in hepatitis C.
 ...
PMID:Hepatocellular proliferation and development of hepatocellular carcinoma: a case-control study in chronic hepatitis C. 982 7

Bcl-2 protein blocks apoptosis and is involved in human intrahepatic bile-duct development. Formalin-fixed, paraffin-embedded archival tissue from 42 HBV and HCV hepatitis [20 acute AH, 22 chronic hepatitis (CH)], 12 active cirrhosis (CR) and 20 hepatocellular carcinoma (HCC) was immunostained for bcl-2 protein. In all cases, bcl-2 protein was detected in portal and intralobular lymphocytes but not in hepatocytes or Kupffer cells. Bcl-2 was positive in the cytoplasm of small portal bile ducts of chronic hepatitis, while it was strongly expressed in newly formed bile-ductules of the limiting plate, mainly in CH with marked activity and CR. Bcl-2 was detected in small bile ducts in only one case of acute hepatitis and was not detected in any case of HCC. Bcl-2 seems to be involved in the regulation of growth and apoptosis of cholangiolar cells. Its expression in small bile ducts and in newly-formed ductules especially in CH with marked activity and CR, implies that the embryonic model of intrahepatic bile duct development may be recapitulated in chronic hepatic disease. Moreover, it supports evidence for the existence of the controversial long-lived stem population in the liver. Bcl-2 does not seem to be involved in hepatocarcinogenesis.
 ...
PMID:Bcl-2 protein expression in acute and chronic hepatitis, cirrhosis and hepatocellular carcinoma. 1004 90

The effect of dietary administration of cholic acid on tumorigenesis in the liver was investigated in male Fischer-344 rats after carcinogenic initiation by diethylnitrosamine (DEN); progression of liver tumors was examined in the rats fed 0.4% cholic acid-containing diet (CA group) and the rats fed standard diet (C group) at 15, 20 and 25 weeks after administration of DEN. The total bile acids and cholic acid in serum of CA group were 150 nmol/ml and 117 nmol/ml, being 31-fold and 51-fold higher than those in C group (p<0.0001, each). Serum AST and ALT were significantly higher in CA group than in C group at 15 weeks (p<0.01). Serum ALP was significantly higher in CA group than C group at each time point (p<0.01, each). Liver tumors, whose histology was hepatocellular carcinoma, developed at 15 weeks in both CA and C groups. However, tumor volume and tumor weight were significantly increased in CA group, compared to those in C group at each time point (p<0.001, p<0. 001, p<0.01, p<0.001, p<0.01 and p<0.05). The percentage of apoptotic cells in CA group at each time point was significantly lower than C group (p<0.05, p<0.01 and p<0.05). The percentage of bcl-2 positive tumor cells in C group at 20 weeks was 1.88+/-2.59%. However, it dramatically increased to 34.00+/-13.67% in CA group (p<0.0001). It was also higher in CA group than in C group at 15 and 25 weeks (p<0.05 and p<0.01). In addition, the bax-positive cells were higher in CA group than in C group at 20 weeks (p<0.05). These data suggest that oral administration of cholic acid promotes liver tumorigenesis initiated by DEN through reducing apoptosis mediated by overexpression of bcl-2.
 ...
PMID:Oral administration of cholic acid promotes growth of liver tumors initiated by diethylnitrosamine in rats. 1040 35

Here, we investigated changes in apoptosis during tumor progression by analyzing the effect of coexpressing various antiapoptotic genes on the multistage process of c-myc-induced hepatocarcinogenesis in transgenic mice. Whereas continuous c-myc gene overexpression in the liver led to cellular hepatocarcinoma, the coexpression of the bcl-2 gene inhibited the emergence of liver tumors, by inhibiting a pretumoral phase characterized by increased proliferation and apoptosis. This antioncogenic effect was specific to Bcl-2 and was not shared by other antiapoptotic genes such as bcl-xL and a dominant negative form of p53. Thus, we have shown that Bcl-2 can have a tumor suppressor effect in vivo on c-myc-induced hepatocarcinogenesis during the emergence of neoplastic foci.
 ...
PMID:Paradoxical inhibition of c-myc-induced carcinogenesis by Bcl-2 in transgenic mice. 1051 17

Immunocytochemistry has indicated that, in the liver, the bcl-2 gene is generally expressed in bile duct cells and tumors of biliary origin. Both in situ hybridization and immunocytochemistry were used to analyze the expression of bcl-2 messenger RNA (mRNA) and its protein product (Bcl-2) in the tissue of 50 pure primary liver tumor (PLT) specimens including 40 hepatocellular carcinoma (HCC) specimens and 10 cholangiocellular carcinoma (CC) specimens. The phenotype of the tumors expressing bcl-2 was confirmed by immunocytochemical assessment of the cytokeratin (CK) profile (CK8, CK18, CK7, and CK19). Whereas positive immunoreaction with the anti-Bcl-2 MoAb was revealed in only 8 (20%) of 40 HCC specimens and 1 (10%) of 10 CC specimens, high contents of bcl-2 mRNA were found in 26 (65%) of 40 HCC specimens and 9 (90%) of 10 CC specimens. Regarding the CK profile, only 25 (62%) of 40 HCC specimens showed pure hepatocytic lineage (CKs 8-18), whereas among the remaining 15 HCC specimens, positivity for either CK7 (12 specimens) or CK19 (5 specimens) was observed. All 10 CC specimens stained with CKs 8-18-19, and 8 of 10 stained with CK 7 as well. These results indicate that PLTs display a greater expression of bcl-2 mRNA than of the Bcl-2 protein. Furthermore, CK profile assessment confirmed that bcl-2 expression is not confined to liver tumors of biliary origin. In the absence of a well-demonstrated post-transcriptional control of the gene, the authors propose the detection of bcl-2 mRNA by in situ hybridization as a possible alternative method for assessing the expression of bcl-2 mRNA in PLT.
 ...
PMID:High levels of BCL-2 messenger RNA detected by in situ hybridization in human hepatocellular and cholangiocellular carcinomas. 1061 75

To investigate the potential use of a bcl-2 antisense oligonucleotide for therapy against hepatocellular carcinoma, we examined the effects of the electroporetic transfer of a bcl-2 antisense oligonucleotide on rat hepatocarcinogenesis induced by N-nitrosomorpholine (NNM). Sprague-Dawley rats were given water containing 175 mg/l NNM for 8 weeks and received intraperitoneal injections of a bcl-2 antisense phosphorothioate oligonucleotide, a sense oligonucleotide or a scrambled sequence oligonucleotide encapsulated in empty liposomes, at a dose of 150 microg oligonucleotide/kg body weight, every 4 weeks. One hour after injection, in vivo electroporation was performed on the liver to achieve selective transfer of the oligonucleotides. By week 16, the rats that had received the bcl-2 antisense oligonucleotide had significantly fewer and smaller precancerous liver lesions positive for glutathione-S-transferase (placental type), and a significantly lower incidence of hepatocellular carcinoma in the electroporation zone than rats that had received the sense or the scrambled oligonucleotides. Moreover, the bcl-2 antisense oligonucleotide significantly increased the apoptotic indices in foci, neoplastic nodules and in hepatocellular carcinomas. The expression of bcl-2 mRNA also decreased, and 3'-fragments of bcl-2mRNA produced by cleavage at the antisense target site were detected in rat liver. Mean cellular fluorescence in the liver increased with higher doses of fluorescein-isothiocyanate-labeled antisense or sense oligonucleotides. Our results show that the electroporetic transfer of bcl-2 antisense oligonucleotide can inhibit rat hepatocarcinogenesis.
 ...
PMID:In vivo electroporetic transfer of bcl-2 antisense oligonucleotide inhibits the development of hepatocellular carcinoma in rats. 1062 87

Expression of the Bcl-2 family members in a human hepatocellular carcinoma cell line (HCC-T) after sodium butyrate-treatment was investigated. Sodium butyrate, a histone deacetylase inhibitor, induced differentiation of the cell line into its normal counterpart without inducing apoptosis at the concentration of 2 mmol/l. Since sodium butyrate has effects on both differentiation and apoptosis, we investigated the expression profile of bcl-2 related genes in HCC-T. The expression of Bcl-2 and Mcl-1/EAT was up-regulated 4-12 h after the treatment while Bcl-XL was up-regulated 2-3 days after the stimulation. On the other hand, the expression levels of Bax protein remained unchanged during differentiation. The HCC-T cells entered a cell cycle arrest at G1 and showed neither cellular fragmentation nor apoptosis during this period, which was concomitantly associated with up-regulated expression of a cell cycle regulator, p21WAF-1. These results demonstrate that induction of anti-apoptotic bcl-2 related proteins at an early stage of differentiation is important for the maintenance of HCC-T cell differentiation by antagonizing pro-apoptotic molecules such as Bax.
 ...
PMID:Bcl-2 related proteins are dramatically induced at the early stage of differentiation in human liver cancer cells by a histone deacetylase inhibitor projecting an anti-apoptotic role during this period. 1067 72

Dibutyryl cyclic AMP (DBcAMP) was previously reported to enhance the down-regulation of the retinoblastoma (RB) protein during G1 phase in proliferating primary rat hepatocytes, but to inhibit their entry into S phase and RB phosphorylation. In the present study, DBcAMP was also found to enhance the down-regulation of RB protein in the human hepatoma cells PLC/PRF/5 after hydroxyurea-induced synchronization at G1/S phase. One hour after synchronization, CPP32 activity was detected in the cells and was further enhanced in the presence of DBcAMP. CPP32-specific cleavage of the RB protein was also detected and enhanced by the addition of DBcAMP in a dose-dependent manner. DNA analysis by flow cytometry after serum starvation-induced synchronization at G0/G1 phase revealed that DBcAMP elicited an apoptotic peak after the S phase. Based on these findings, DBcAMP was suspected of inducing apoptosis by RB protein degradation during G1/S transition and thereby inhibit the growth of PLC/PRF/5 cells. Under serum-deficient culture conditions, addition of the CPP32 inhibitor DEVD or the ICE inhibitor YVAD enhanced cell growth but did not abolish the DBcAMP-induced growth inhibition. On the other hand, antisense oligodeoxynucleotides against Bcl-2 mRNA showed a growth inhibitory effect on PLC/PRF/5 cells, but did not show an additive effect on the DBcAMP-induced growth inhibition. DBcAMP itself inhibited bcl-2 protein expression. DBcAMP-induced growth inhibition may be mediated by different mechanisms, including apoptosis.
 ...
PMID:Dibutyryl cyclic AMP-induced enhancement of RB protein degradation in human hepatoma cells. 1069 31


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>