CpG island methylator phenotype association with elevated serum alpha-fetoprotein level in hepatocellular carcinoma.

PURPOSE: CpG island methylator phenotype (CIMP) involves hypermethylation targeted toward the promoters of multiple genes. To gain insight into the role of epigenetic aberration of tumor-related genes in hepatocarcinogenesis, we determined a hypermethylation profile in hepatocellular carcinoma (HCC). EXPERIMENTAL DESIGN: We examined the promoter methylation status of nine genes in 50 HCCs, 50 paired nontumor tissues, and 6 normal liver tissues by methylation-specific PCR. CIMP+ was defined as having five genes that are concordantly methylated. RESULTS: The frequency of promoter methylation of nine genes in 50 HCCs varied from 10% in P53 to 94% in c-Myc. The methylation status of P14, P15, P16, ER, RASSF1A, WT1, and c-Myc was significantly correlated with HCC and nontumor tissues (P<0.05). Hypermethylation of one or more genes was found in 96% of HCC. CIMP was more frequent in HCC than in nontumor tissues (70% and 12%, P<0.001). There is a significant association between CIMP and methylation of P14, P15, P16, ER, RSAAF1A, and WT1 (P<0.05) and serum alpha-fetoprotein (AFP) level (P=0.017). CIMP+ was more frequent in HCC with AFP>or=30 microg/L than those with AFP<30 microg/L (P=0.005). In addition, the promoter hypermethylation of P15 and P16 was associated with elevated serum AFP levels in 35 HCC samples with CIMP+ (P<0.05). CONCLUSIONS: Positive correlation of CIMP and AFP levels in HCC suggests that CIMP can serve as a molecular marker of late-stage HCC development.     

GPC3基因在原发性肝癌中的表达意义

目的分析GPC3基因在肝癌组织和癌周组织中的表达及对原发性肝癌的诊断价值。方法从20例原发性肝癌及相对应的癌周组织提取总RNA,利用RT-PCR方法对AFP、GPC3基因进行半定量分析。结果AFP、GPC3基因在癌组织和癌周组织的表达存在显著差异,在癌组织的表达率分别为70.0%和75.0%,联合应用达80.0%,在癌周组织的表达率均为10.0%,组织AFP mRNA的表达与血清AFP相关,而GPC3 mRNA的表达不受血清AFP值影响,在血清AFP≤20 ug/l的肝癌组织中,GPC3 mRNA表达率为40.0%（4/8）。结论GPC3 mRNA在肝癌癌组织中的表达明显高于癌周组织的表达,GPC3基因对血清AFP阴性肝癌有一定的辅助诊断意义,可能是肝癌的一种新的潜在的肿瘤特异标志物。     

Decreased expression of cytochrome P450 2E1 is associated with poor prognosis of hepatocellular carcinoma

Cytochrome P450-2E1 (CYP2E1) is one of the major hepatic enzymes involved in the metabolism of procarcinogen. Our study aimed to investigate the differential expression level of CYP2E1 and its clinicopathological significance in hepatocellular carcinoma (HCC). CYP2E1 revealed low level of expression in 70% of the tumor tissues, when compared to the adjacent nontumor tissues, at both mRNA and protein levels. The low expression of CYP2E1 was significantly correlated with the aggressive tumor phenotype, including poor differentiation status (by the Edmondson grading system) (p=0.038), absence of tumor capsule (p=0.030) and younger age of the patients (p=0.002). Multivariate analysis indicated that CYP2E1 expression level and pTNM stage were independent prognostic factors for disease-free survival. CYP2E1 was also shown to have a differential expression level in different liver tissues. The level of CYP2E1 was significantly higher in nontumor tissues from HCC patients compared to the intermediate level in cirrhosis livers from noncancer patients and normal livers from healthy persons. Tumor tissues were shown to have the lowest expression level. In conclusion, our results have shown that CYP2E1 is upregulated in the nontumor tissue and downregulated in tumor tissue, which is associated with aggressive tumor type and poor prognosis of the patients. It suggested that the differential expression of CYP2E1 may play an important role in HCC tumorigenesis.     

GEP associates with wild-type p53 in hepatocellular carcinoma

Granulin-epithelin precursor (GEP) is a novel growth factor whose up-regulation we previously reported in 72% of hepatocellular carcinoma (HCC). GEP expression has been reported to be associated with p53 protein accumulation in a breast cancer study, though the p53 mutation status was not revealed. We aim to investigate whether p53 protein and mutation status correlates with GEP expression in HCC. The statistical comparison of p53 and GEP data revealed an overall positive association between the two protein expression patterns (P<0.001). Upon detailed analysis, the association of p53 and GEP protein expression was found to be highly significant only in HCCs with wild-type p53 (P=0.001); there was no association in HCCs with p53 mutation (P=0.669). The GEP levels in the HepG2 hepatoma cell line with a wild-type p53 background were modulated by transfection experiments. Overexpression of the GEP protein resulted in an increased p53 protein level and suppression of the GEP protein resulted in a decreased p53 protein level in HepG2 cells. In summary, we demonstrated that p53 wild-type protein nuclei accumulation is associated with GEP protein expression in human HCC specimens, and GEP modulates p53 wild-type protein levels in vitro.     

原发性肝细胞癌p21WAF1和p16表达及意义

[目的]研究p21WAF1、p16在原发性肝细胞癌(HCC)中的表达及意义.[方法]利用免疫组织化学技术检测74例HCC中p21WAFI、p16蛋白表达.[结果]p16蛋白在HCC中表达的阳性率为51.35%,p21WAF1蛋白的表达率为43.24%,而正常肝组织中为100%,两组均有显著性差异(P＜0.05).p16蛋白在有转移的HCC中阳性率为23.08%,明显低于无转移HCC的阳性率(71.43%,P＜0.05).[结论]p16及p21WAF1蛋白的缺失与HCC的发生发展有关.p16蛋白的缺失与HCC转移有关.     

HIF-1α和VEGF 的表达与肝细胞癌侵袭转移的关系

 目的 探讨HIF-1α、VEGF的蛋白表达与肝细胞癌血管新生及侵袭转移特性之间的关系。方法 采用免疫组化SP法检测肝细胞癌、癌旁肝组织和正常肝组织中HIF-1α、VEGF的表达，并计数MVD值。结果 HIF-1α在肝细胞癌中的阳性表达率为50．0％，显著高于癌旁（16．1％）和正常肝组织的（8．3％）（P=0．001）；VEGF在肝细胞癌中的阳性表达率为81）％，显著高于癌旁（59．4％）和正常肝组织（41．7％）（P=0．044）；肝细胞癌组织中MVD值显著高于癌旁和正常肝组织（P=0．001）。HIF-1α蛋白表达与有无门静脉或胆管癌栓及肿瘤分化程度有关（P〈0．05）；VEGF蛋白的表达与有无肝内或淋巴结转移及有无门静脉或胆管癌栓有关（P〈0．05）。HF-1α与VEGF表达有关（P=0．005）；HF-1α与VEGF共同表达阳性组的MVD值显著高于共同表达阴性组MVD值（P=0．001）。结论 HF-1α可能通过调节VEGF的表达促进肝细胞癌血管新生，从而促使肝细胞癌侵袭转移。     

Relationship between elevated FX expression and increased production of GDP-L-fucose, a common donor substrate for fucosylation in human hepatocellular carcinoma and hepatoma cell lines

The levels of fucosylated glycoproteins in various cancers and inflammatory processes have been a subject of intense study. The level of fucosyltransferases and intracellular GDP-L-fucose, a sugar nucleotide and a common donor substrate for all fucosyltransferases, may regulate the level of fucosylated glycoproteins. This study reports on the determination of GDP-L-fucose levels in human hepatocellular carcinoma (HCC) and surrounding tissues, using a recently established high-throughput assay system. Levels of GDP-L-fucose in HCC tissues were significantly increased compared with adjacent nontumor tissues or normal livers. The mean +/- SD for GDP-L-fucose level was 3.6 +/- 0.2 micro mol/mg in control liver, 4.6 +/- 0.9 micro mol/mg in adjacent noninvolved liver tissues (chronic hepatitis, 4.4 +/- 0.7 micro mol/mg; liver cirrhosis, 4.8 +/- 0.9 micro mol/mg), and 7.1 +/- 2.5 micro mol/mg in HCC tissues. The level of GDP-L-fucose in HCC decreased in proportion with tumor size (r = -0.675, P = 0.0002). When expression of the series of genes responsible for GDP-L-fucose synthesis was investigated, the gene expression of FX was found to be increased in 70% (7 of 10) of the HCC tissues examined compared with that in their surrounding tissues. The levels of GDP-L-fucose were positively correlated with the expression of FX mRNA (r = 0.599, P = 0.0074). The levels of FX gene expression in some human hepatoma and hepatocyte cell lines were determined. FX mRNA production was strongly increased in HepG2 and Chang liver, moderately increased in Hep3B and HLF, and, in HLE, was similar to that of a normal human liver tissue. To investigate the effect of GDP-L-fucose on core fucosylation, FX cDNA was transfected into Hep3B cells, which express a relatively low level of GDP-L-fucose:N-acetyl-beta-D-glucosaminide alpha1-6 fucosyltransferase (alpha1-6 FucT) and FX mRNA. Transfection of this gene caused an increase in GDP-L-fucose levels as well as the extent of fucosylation on glycoproteins, including alpha-fetoprotein, as judged by reactivity to lectins. Collectively, the results herein suggest that the high level of fucosylation in HCC is dependent on a high expression of FX followed by increases in GDP-L-fucose, as well as an enhancement in alpha1-6 FucT expression. Thus, an elevation in GDP-L-fucose levels and the up-regulation of FX expression represent potential markers for HCC.     

Activation of a system A amino acid transporter, ATA1/SLC38A1, in human hepatocellular carcinoma and preneoplastic liver tissues

The expression of amino acid transporter (AT) mRNAs including A system (ATA1/SNAT1/SLC38A1, ATA2/SNAT2/SLC38A2 and ATA3/SNAT3/SLC38A4), L system (LAT1/SLC7A5 and LAT2/SLC7A8), and y+ (CAT2/SLC7A2) genes, were compared among hepatocellular carcinoma (HCC) and non-cancerous liver cells. Among them the ATA1 mRNA expression was significantly elevated in all HCC cell lines (HepG2, HLF, HuH7 and JHH4) examined compared with normal liver tissue. We further discovered that the expression of ATA1 mRNA was significantly activated in HCC tissues and also elevated in pre-malignant cirrhotic livers from HCC patients, compared with normal livers from non-HCC patients. The ATA1 protein was extensively accumulated in the cytoplasm of pre-malignant liver and most HCCs, while being weak or undetectably low in normal liver tissues. SiRNA-mediated suppression of endogenous ATA1 lowered the viability of HepG2 cells. Thus, the activation of ATA1 confers growth and survival advantages in pre-malignant and malignant liver lesions.     

WDRPUH, a novel WD-repeat-containing protein, is highly expressed in human hepatocellular carcinoma and involved in cell proliferation

In an attempt to disclose mechanisms of hepatocarcinogenesis and discover novel target molecules for the diagnosis and treatment of hepatocellular carcinomas (HCCs), we previously analyzed expression profiles of HCC tissues by means of human cDNA microarray. Among the genes upregulated in tumor tissues compared with their nontumor counterparts, we focused on a novel gene, termed WDRPUH, and characterized its biologic function. WDRPUH encodes a predicted 620-amino acid protein containing 11 highly conserved WD40-repeat domains. Multiple-tissue Northern blot analysis revealed its specific expression in the testis among 16 normal tissues examined. Transfection of plasmids designed to express WDRPUH-specific siRNA significantly reduced its expression in HCC cells and resulted in growth suppression of transfected cells. Interestingly, we found that WDRPUH associated with HSP70, proteins of the chaperonin-containing TCP-1 (CCT1) complex, as well as BRCA2. These findings have disclosed a novel insight into hepatocarcinogenesis and suggested that WDRPUH may be a molecular target for the development of new strategies to treat HCCs.     

Identification of genes preferentially methylated in hepatitis C virus‐related hepatocellular carcinoma

Chronic infections by hepatitis B virus (HBV) and hepatitis C virus (HCV) appear to be the most significant causes of hepatocellular carcinoma (HCC). Aberrant promoter methylation is known to be deeply involved in cancer, including in HCC. In this study, we analyzed aberrant promoter methylation by methylated DNA immunoprecipitation‐on‐chip analysis on a genome‐wide scale in six HCCs including three HBV‐related and three HCV‐related HCCs, six matched noncancerous liver tissues, and three normal liver tissues. Candidate genes with promoter methylation were detected more frequently in HCV‐related HCC. Candidate genes methylated preferentially to HBV‐related or HCV‐related HCCs were detected and selected, and methylation levels of the selected genes were validated by quantitative methylation analysis using MALDI‐TOF mass spectrometry using 125 liver tissue samples, including 61 HCCs (28 HBV‐related HCCs and 33 HCV‐related HCCs) and 59 matched noncancerous livers, and five normal livers. Among analyzed genes, preferential methylation in HBV‐related HCC was validated in one gene only. However, 15 genes were found to be methylated preferentially in HCV‐related HCC, which was independent from age. Hierarchical clustering of HCC using these genes stratified HCV‐related HCC as a cluster of frequently methylated samples. The 15 genes included genes inhibitory to cancer‐related signaling such as RAS/RAF/ERK and Wnt/β‐catenin pathways. Methylation of dual specificity phosphatase 4 (DUSP4), cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1), and natriuretic peptide receptor A (NPR1) significantly correlated with recurrence‐free survival. It was indicated that genes methylated preferentially in HCV‐related HCC exist, and that DNA methylation might play an important role in HCV‐related HCC by silencing cancer‐related pathway inhibitors, and might perhaps be useful as a prognostic marker. (Cancer Sci 2010)     

Shortened Telomere Length in Hepatocellular Carcinomas and Corresponding Background Liver Tissues of Patients Infected with Hepatitis Virus

The telomere length in 20 surgically resected human hepatocellular carcinomas (HCCs) and adjacent non-cancerous, livers with hepatitis virus infection were investigated. All the HCC samples examined demonstrated shorter telomere length than the corresponding non-cancerous liver tissues, the respective average values being 5.4 kbp and 8.8 kbp ( P < 0.001). The shortening of telomere length was most prominent in HCCs larger than 30 mm in diameter, and in both tumors and non-cancerous livers it was more marked with hepatitis B virus as compared with hepatitis C virus infection. These results indicate that telomere shortening is associated with not only progression, but also development of HCC, and there is a possible difference in the nature of the association in patients with hepatitis viruses of B and C types.     

Increased protein expression of DNA methyltransferase (DNMT) 1 is significantly correlated with the malignant potential and poor prognosis of human hepatocellular carcinomas

Alteration of DNA methylation is one of the most consistent epigenetic changes in human cancers. DNA methyltransferase (DNMT) 1 is a major enzyme involved in establishing genomic methylation patterns. Most of the studies concerning DNMT1 expression in human cancers have been performed only at the mRNA level. To directly examine DNMT1 protein expression levels during human hepatocarcinogenesis, 16 histologically normal liver tissues, 51 noncancerous liver tissues exhibiting chronic hepatitis or cirrhosis, which are considered to be precancerous conditions, and 53 hepatocellular carcinomas (HCCs) were subjected to immunohistochemic examination. If more than 20% of the cells exhibited nuclear DNMT1 staining, the tissue sample was considered to be DNMT1-positive. DNMT1 immunoreactivity was observed in 23 (43%) of the HCCs, but in none (0%) of the histologically normal liver or noncancerous liver tissues exhibiting chronic hepatitis or cirrhosis. The incidence of increased DNMT1 protein expression in HCCs correlated significantly with poor tumor differentiation (p = 0.0006) and portal vein involvement (p = 0.0002). Moreover, the recurrence-free (p = 0.0001) and overall (p < 0.0001) survival rates of patients with HCCs exhibiting increased DNMT1 protein expression were significantly lower than those of patients with HCCs that did not exhibit increased expression. Increased DNMT1 protein expression may play a critical role in the malignant progression of HCCs and be a biologic predictor of both HCC recurrence and a poor prognosis in HCC patients.