Tumor suppressor genes, growth factor genes, and oncogenes in hepatitis B virus-associated hepatocellular carcinoma

Impact of metformin use on the recurrence of hepatocellular carcinoma after initial liver resection in diabetic patients

Background

Metformin is proposed to have chemopreventive effect of various cancer currently. However, the anti-cancer effect of metformin for diabetic patients with hepatocellular carcinoma (HCC) undergoing liver resection remains unclear. The aim of our cohort study was to assess whether metformin influence the recurrence of HCC.

Methods

We retrospectively enrolled 857 HCC patients who received primary resection from April 2001 to June 2016. 222 patients were diagnosed with diabetes mellitus (DM) from medical record. Factors influence the overall survival (OS) and recurrence-free survival (RFS) were analyzed by multivariate analysis.

Results

During the follow-up period (mean, 75 months), 471 (54.9%) patients experienced recurrence, and 158 (18.4%) patients died. Multivariate analysis revealed that DM (p = 0.015), elevated AST (p = 0.006), hypoalbuminemia (p = 0.003), tumor number (p = 0.001), tumor size (p < 0.001), vascular invasion (p <0.001), high Ishak fibrosis score (p <0.001), hepatitis B (p = 0.014), hepatitis C (p = 0.001) were independent predictors for RFS. In diabetic patients, only HbA1c>9% (p = 0.033), hypoalbuminemia (p = 0.030) and vascular invasion (p = 0.001) were independent risk factors for HCC recurrence; but the metformin use revealed no significance on recurrence. DM is a risk factor of HCC recurrence after resection. Adequate DM control can reduce the recurrence of HCC. However, the use of metformin does not reduce the risk of HCC recurrence in diabetic patient after initial resection. Hence, metformin may not have protective influences on HCC recurrence in diabetic patients who undergo initial liver resection.

Prognostic significance of c-Met, β-catenin and FAK in patients with hepatocellular carcinoma following surgery

The present study aimed to investigate the prognostic value of specific molecular markers in patients with hepatocellular carcinoma (HCC) who had received surgery. Immunohistochemical analysis was used to measure the expression of hepatocyte growth factor receptor (c-Met), β-catenin and focal adhesion kinase (FAK) in patients with HCC. c-Met expression was identified to be high in patients with larger tumors, higher α-fetoprotein (AFP) levels, higher Edmondson grades, portal vein invasion and higher tumor-node-metastasis (TNM) stages. FAK expression was high in patients with portal vein invasion, higher Edmondson grades and higher TNM stages. β-catenin expression was high in patients with larger tumors, hepatitis B virus (HBV) infection, portal vein invasion, higher Edmondson grades and higher TNM stages. Following multivariate analysis, FAK (P=0.002) and β-catenin (P=0.006) expression levels were demonstrated to be significantly associated with Edmondson grade. Additionally, the tumor size (P=0.009) and HBV infection status (P=0.002) were revealed to be associated with β-catenin expression. Kaplan-Meier survival curve analysis demonstrated that patients with HCC with higher FAK expression, higher β-catenin expression, portal vein invasion, higher Edmondson grades, higher TNM stages, younger ages and higher AFP levels had significantly poorer prognoses. Cox's regression analysis revealed that the survival period was correlated with the Edmondson grade, age, AFP level, and FAK and β-catenin expression. Univariate analysis of c-Met, β-catenin and FAK identified a significant correlation between FAK and β-catenin (P=0.015). Correlation analysis revealed no significant correlation between the three molecular markers, but β-catenin and c-Met were markedly correlated (P=0.052). No significant correlation between FAK, c-Met or β-catenin expression was identified. FAK and β-catenin expression demonstrated a correlation with a range of clinicopathological factors, and high FAK and β-catenin expression levels were identified to be correlated with a poor survival rate of patients with HCC. Thus, patients with higher FAK and β-catenin expression may require more aggressive therapy. The results of the present study suggest that FAK and β-catenin expression possess more prognostic value than c-Met expression in patients with HCC.

Transarterial chemoembolization combined with recombinant human adenovirus type 5 H101 prolongs overall survival of patients with intermediate to advanced hepatocellular carcinoma: a prognostic nomogram study

Background

Patients with intermediate to advanced hepatocellular carcinoma (HCC) are most commonly treated with transarterial chemoembolization (TACE). Previous studies showed that TACE combined with recombinant human adenovirus type 5 (H101) may provide a clinical survival benefit. In the present study, we aimed to determine the survival benefit of TACE with or without H101 for patients with intermediate to advanced HCC and to develop an effective nomogram for predicting individual survival outcomes of these patients.

Methods

We retrospectively collected data from 590 patients with intermediate to advanced HCC who were treated at Sun Yat-sen University Cancer Center between January 2007 and July 2015. After propensity score matching, 238 patients who received TACE with H101 (TACE with H101 group) and 238 patients who received TACE without H101 (TACE group) were analyzed. Overall survival (OS) was evaluated using the Kaplan–Meier method; the nomogram was developed based on Cox regression analysis. Discrimination and calibration were measured using the concordance index (c-index) and calibration plots.

Results

Clinical and radiologic features were similar between the two groups. OS rates were significantly lower in the TACE group than in the TACE with H101 group (1-year OS rate, 53.8% vs. 61.3%; 2-year OS rate, 33.4% vs. 44.2%; 3-year OS rate, 22.4% vs. 40.5%; all P < 0.05). Multivariate Cox regression analysis for the entire cohort showed that alpha-fetoprotein level, alkaline phosphatase level, tumor size, metastasis, vascular invasion, and TACE with or without H101 were independent factors for OS, all of which were included in the nomogram. Calibration curves showed good agreement between nomogram-predicted survival and observed survival. The c-index of the nomogram for predicting OS was 0.716 (95% confidence interval 0.686–0.746).

Conclusions

TACE plus H101 extends the survival of patients with intermediate to advanced HCC. Our proposed nomogram provides individual survival prediction and stratification for patients with intermediate to advanced HCC who receive TACE with or without H101.

cDNA Microarray Analysis in Hepatocyte Differentiation in Huh 7 Cells

The risk of xenozoonosis infections poses the greatest obstacle against the clinical application of a hybrid artificial liver support system (HALSS). Primary human hepatocytes are an ideal source for HALSS, but the shortage of human livers available for hepatocyte isolation limits this modality. To resolve this issue, we previously demonstrated the upregulation of hepatocyte-specific function by spheroid formation in polyurethane foam and by culturing with the histone deacetylase inhibitor, trichostatin A (TSA), in a human hepatoma cell line (Huh 7). In this article we analyze the gene expression profile using cDNA microarray (1281 genes) in spheroid formation or culturing with TSA in Huh 7 to determine the target genes in hepatocyte differentiation. In both the spheroid formation and in the culture with TSA, the Oct-3/4 transcription factor was upregulated more than twofold, while the early growth response-1 (EGR-1) transactivator was downregulated less than 0.5-fold. These results indicate that expressions of Oct-3/4 and EGR-1 may be key factors in the induction of hepatocyte differentiation in Huh 7.

Transarterial injection of recombinant human type-5 adenovirus H101 in combination with transarterial chemoembolization (TACE) improves overall and progressive-free survival in unresectable hepatocellular carcinoma (HCC)

Background

The aim of this study was to determine the clinical benefit of transhepatic arterial chemoembolization (TACE) with or without recombinant human adenovirus type 5 (H101) administration for the treatment of patients with hepatocellular carcinoma (HCC).

Methods

Tumor response, progression-free survival (PFS), and overall survival(OS) were retrospectively evaluated in consecutive patients with unresectable HCC who received TACE with or without H101 between April 2012 and April 2013.

Results

Patients with unresectable HCC were treated with transarterial injection of H101 with TACE (H101 group, n = 87) or TACE alone (control group, n = 88). Clinicopathological features were similar between the groups. Treatment response was significantly different between the groups (P = 0.01). In the H101 group, 25 patients demonstrated a complete response (CR, 28.7 %); 28 patients, a partial response (PR, 32.2 %); 23 patients, stable disease (SD, 26.4 %); and 11 patients, progressive disease (PD, 12.6 %). In the control group, 13 patients demonstrated CR (14.8 %); 19, PR (21.6 %); 34, SD (38.6 %); and 22, PD (25 %). OS and PFS was also significantly different between the groups. In the H101 group, median OS and PFS were 12.8 and 10.49 months, whereas in the control group they were 11.6 and 9.72 months, respectively (OS: P = 0.046; PFS: P = 0.044).

Conclusion

In patients with unresectable HCC, H101 combined with TACE improves OS, PFS and treatment response compared with TACE alone.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1715-x) contains supplementary material, which is available to authorized users.

Two-stage model of chemically induced hepatocellular carcinoma in mouse

The aim of this study was to develop an efficient and reproducible mouse model for hepatocellular carcinoma (HCC) research and assess the expression of two proto-oncogenes (c-myc and N-ras) and tumor suppressor gene p53 in the carcinogenic process. In this study, we found that diethylnitrosamine initiation with CCl4 and ethanol promotion could induce a short-term, two-stage liver carcinogenesis model in male BALB/c mice, the process of hepatocarcinogenesis including liver damage, liver necrosis/cell death, liver inflammation, liver proliferation, liver hyperplasia, liver steatosis, and liver cirrhosis and hepatocellular nodules, which mimicked the usual sequence of events observed in human HCC. We also identified that the increase in expression of the p53 gene is related to the proliferation of hepatocytes, whereas overexpression of the c-myc and N-ras genes is associated with hepatocarcinogenesis. This animal model may serve as a basis for recapitulating the molecular pathogenesis of HCC seen in humans.

Decreased expression of PTPN12 correlates with tumor recurrence and poor survival of patients with hepatocellular carcinoma

Background

Protein tyrosine phosphatase non-receptor type 12 (PTPN12), has been identified as a potent tumor suppressor in human cancers and a critical regulator of cell adhesion and migration. However, the PTPN12 expression and its prognostic significance in HCC have not been well elucidated.

Methodology/Principal Findings

In this study, tissue microarray-based immunohistochemistry (IHC) was investigated in an HCC cohort with adjacent liver tissues as controls. The resulting data were analyzed using receiver operating characteristic curves, Spearman's rank correlation, Kaplan-Meier plots and Cox proportional hazards regression modeling. Our results showed that decreased expression of PTPN12 was more frequently observed in HCC tissues compared to the adjacent non-tumorous liver tissues. Further correlation analyses indicated that the decreased PTPN12 expression was closely correlated with tumor recurrence (P = 0.015). Univariate analysis showed a significant association between decreased expression of PTPN12 and adverse cancer-specific survival and recurrence-free survival (P<0.001). In different subsets of overall patients, PTPN12 expression was also a prognostic indicator in patients with stage I/II or stage III/IV (P<0.05). Importantly, multivariate analysis (P<0.05) identified PTPN12 expression in HCC as an independent prognostic factor.

Conclusions/Significance

Our findings provide a basis for the concept that PTPN12 protein expression is frequently decreased or lost in human HCC tissues and that decreased PTPN12 expression may represent an acquired recurrence phenotype of HCC and that PTPN12 expression may act as a biomarker of prognosis for patients with HCC.

Prognostic significance of p53, mTOR, c-Met, IGF-1R, and HSP70 overexpression after the resection of hepatocellular carcinoma

Background/Aims

The current study examines the expression of molecular biomarkers in hepatocellular carcinoma (HCC) and whether these findings correlate with the clinicopathologic features of the disease and patient survival.

Methods

We analyzed the immunohistochemical expression of p53, mammalian target of rapamycin (mTOR), c-Met, and insulin-like growth factor 1 receptor (IGF-1R) heat shock protein 70 (HSP70) with the clinicopathologic features of 83 HCCs.

Results

p53 expression was higher in the male patients with undifferentiated histological tumor grades, cirrhosis, and portal vein invasion. High 48 c-Met expression correlated with cirrhosis, and high mTOR expression correlated with the tumor grade and cirrhosis. High IGF-1R expression correlated with the tumor grade and cirrhosis. A multivariate analysis identified a significant relationship between the high expression of p53, tumor grade, and portal vein invasion. In addition, a high expression of mTOR was related to tumor grade and cirrhosis, and a high expression of HSP70 was related to portal vein invasion in a multivariate analysis. The Kaplan-Meier survival curve for patients with high versus low Edmondson grades and p53 expression was statistically significant.

Conclusions

p53, mTOR, and IGF-1R expression correlated with the Edmondson tumor grade in a univariate analysis, while p53 and mTOR correlated with the Edmondson tumor grade in a multivariate analysis. In addition, the tumor grade was found to predict survival. p53 was primarily related to the clinicopathologic features compared to other markers, and it is a poor prognostic factor of survival.

Evaluation of Fbxw7 expression and its correlation with the expression of c-Myc, cyclin E and p53 in human hepatocellular carcinoma

AIM

  F-box and WD repeat domain-containing 7 (Fbxw7) is a cell cycle regulatory gene that targets for ubiquitination and proteasomal degradation various cell cycle regulators such as c-Myc and cyclin E. Defects in the Fbxw7 gene that lead to cell cycle re-entry and expedite the G1-S transition is thought to be one of the causes of cancer development. However, its expression and clinical importance for hepatocellular carcinoma (HCC) patients remains undetermined. This prompted us to investigate its expression level in HCC patients to establish its clinical significance.

METHODS

  Sixty surgically resected paired HCC and normal tumor-adjacent tissues were freshly collected. Fbxw7 expression at both mRNA and protein level was examined by reverse transcription polymerase chain reaction and immunohistochemistry. The protein expression of c-Myc, cyclin E and p53 was evaluated by immunohistochemistry to identify correlations with Fbxw7.

RESULTS

  The mRNA and protein expression of Fbxw7 was significantly downregulated in the HCC tumor tissues compared to the normal tumor-adjacent tissues (P < 0.01, respectively). Fbxw7 protein was expressed at significantly lower levels in patients with high histological grade and advanced tumor-node-metastasis stage. In HCC tissues, Fbxw7 protein expression was negatively correlated with c-Myc, cyclin E and p53 (r = -0.459, P < 0.05; r = -0.573, P < 0.001; r = -0.579, P < 0.05, respectively).

CONCLUSION

  In HCC, reduced Fbxw7 expression closely correlated with clinicopathological characteristics and may have prognostic potential through the enhanced function of cell cycle regulatory proteins.

Diabetes mellitus is associated with increased mortality in patients receiving curative therapy for hepatocellular carcinoma

BACKGROUND

Diabetes mellitus (DM) is closely associated with hepatocarcinogenesis. This study explores the prognostic impact of DM in patients who received curative therapy for localized hepatocellular carcinoma (HCC).

METHODS

Patients who had been diagnosed with stage I or II HCC in 2003 and 2004 and received surgical resection or local ablation therapy were identified from the population-based Taiwan National Cancer Registry. Data pertaining to DM and other comorbidities were retrieved from the Taiwan National Health Insurance database. Liver cancer-specific survival (LCS), liver disease-related survival (LDS) and overall survival (OS) rates were compared between patients with and without DM. The presence of other comorbidities and tumor status were adjusted using multivariate analysis.

RESULTS

A total of 931 patients who fulfilled the study criteria were analyzed; 185 (20%) of them had DM (type 1 or type 2). The LCS, LDS, and OS rates were significantly worse for patients with DM than patients without DM (all p < .001). After adjusting for age, sex, tumor stage, treatment, and the presence of other comorbidities, DM remained an independent predictor of poorer LCS (hazard ratio [HR] = 1.57; p < .001), LDS (HR = 1.70; p < .001), and OS (HR = 1.69; p < .001). The associations between DM and mortality were consistent among subgroups, irrespective of tumor size, stage, treatment modality, and liver cirrhosis.

CONCLUSIONS

DM is an independent factor for poorer prognosis in patients who received curative therapy for localized HCC.

High expression of H3K27me3 in human hepatocellular carcinomas correlates closely with vascular invasion and predicts worse prognosis in patients

It has been suggested that trimethylation of lysine 27 on histone H3 (H3K27me3) is a crucial epigenetic process in tumorigenesis. However, the expression dynamics of H3K27me3 and its clinicopathological/prognostic significance in hepatocellular carcinoma (HCC) are unclear. In this study, immunohistochemical analysis (IHC) was used to examine protein expression of H3K27me3 in HCC tissues from two independent cohorts and corresponding nontumorous hepatocellular tissues by tissue microarray. The optimal cutpoint of H3K27me3 expression was assessed by the X-tile program. Our results showed that the cutpoint for high expression of H3K27me3 in HCCs was determined when more than 70% of the tumor cells showed positive staining. High expression of H3K27me3 was observed in 134 of 212 (63.2%) and 76 of 126 (60.4%) of HCCs in the testing and validation cohorts, respectively. Correlation analysis demonstrated that high expression of H3K27me3 in HCCs was significantly correlated with large tumor size, multiplicity, poor differentiation, advanced clinical stage and vascular invasion (P < 0.05). In addition, high expression of H3K27me3 in HCC patients was associated closely with shortened survival time, independent of serum α-fetoprotein levels, tumor size and multiplicity, clinical stage, vascular invasion and relapse as evidenced by univariate and multivariate analysis in both cohorts (P < 0.05). In different subsets of HCC patients, H3K27me3 expression was also a prognostic indicator in patients with stage II tumors (P < 0.05). Thus, these findings provide evidence that a high expression of H3K27me3, as detected by IHC, correlates closely with vascular invasion of HCCs and is an independent molecular marker for poor prognosis in patients with HCC.

Interleukin-17F suppresses hepatocarcinoma cell growth via inhibition of tumor angiogenesis

Previous studies have shown that interleukin-17F (IL-17F) can markedly inhibit the angiogenesis of endothelial cells, implying that it may play a role in antiangiogenic therapy for tumors. To explore its effect on antiangiogenic therapy for hepatocellular carcinoma (HCC), we constructed a recombinant retrovirus vector RV-IL-17F expressing IL-17F, transfected SMMC-7721 human hepatocarcinoma cells with RV-IL-17F, and investigated the effect of transgene IL-17F expression on human hepatocarcinoma cells in vitro and in vivo in animal model. We demonstrated that IL-17F expression exerted no direct effect on in vitro proliferation and cell cycle of SMMC-7721 hepatocarcinoma cells, while it downregulated IL-6, IL-8, and VEGF expression in SMMC-7721 cells at both protein and mRNA levels and IL-17F-expressing supernatant from SMMC-7721/RV-IL-17F directly inhibited ECV304 vascular endothelial cell growth. Moreover, SMMC-7721/RV-IL-17F exhibited a significant decrease in tumor size and microvessel density as compared to the SMMC-7721/RV control when transplanted in nude mice. This retarded tumor growth in vivo elicited by IL-17F was associated with direct suppression of vascular endothelial cells and reduced expression of proangiogenic factors IL-6, IL-8, and VEGF leading to the inhibition of tumor angiogenesis. Thus, our results indicate that IL-17F, a novel antiangiogenic factor, may be useful in antiangiogenic therapy for HCC.

Accelerated expression of a Myc target gene Mina53 in aggressive hepatocellular carcinoma

AIM

Expressions of the myc target genes Mina53 and mimitin are high in esophageal squamous cell carcinoma and colon cancer, and their relationship to cell proliferation and patient prognosis has been reported. Because c-myc gene expression is closely related to hepatocellular carcinoma (HCC) growth or formation and/or maintenance, we examined the Mina53 and mimitin expressions in HCC.

METHODS

Surgically resected 53 HCC tissues were immunohistochemically examined for Mina53 and mimitin expressions and their relationship to clinicopathological factors.

RESULTS

Diffuse Mina53 expression was observed in the nuclei of cancer cells in the tumor nodule, but was often strong at the periphery of tumor nodules. Diffuse or scattered expression of mimitin was observed in the cytoplasm of HCC cells in tumor nodules. Mina53 expression was higher in poorly differentiated HCC than in well-differentiated HCC, and significant relationship to histological grade was observed. The cases with a high Mina53 expression also had a high expression of a proliferation marker MIB-1. This suggested the involvement of Mina53 in cell proliferation. Mina53 expression was high in the tumors of >2 cm of diameter than in </=2 cm (P < 0.01). Mimitin expression tended to be high in tumors of >2 cm, but no significant relationship was observed either to histological grade, MIB-1 expression, or the other clinicopathologic factors.

CONCLUSIONS

Our findings suggested that Mina53 expression is accelerated in HCC with a lower histological grade, with cell proliferation capability, or with a larger diameter, and Mina53 is related to biological malignancy of HCC.

Dual knockdown of N-ras and epiregulin synergistically suppressed the growth of human hepatoma cells

Hepatocellular carcinoma (HCC) is a major challenge because of its resistance to conventional cytotoxic chemotherapy and radiotherapy. Multi-targeted therapy might be a new option for HCC treatment. Our previous study showed that N-ras gene was activated in HCC and was inhibited by RNA interference. In the present study, we investigated the alternation of gene expression by microarray in N-Ras-siRNA-treated HepG2 cells. The results revealed that the EREG gene, encoding epiregulin, was dramatically up-regulated in response to silence of N-ras. We speculated that the up-regulation of epiregulin was involved in the compensatory mechanism of N-ras knockdown for cell growth. Therefore, we evaluated whether dual silence of N-ras and epiregulin display a greater suppression of cell growth. The results confirmed that dual knockdown of N-ras and epiregulin synergistically inhibited cell growth. Our results also showed that dual knockdown of N-ras and epiregulin significantly induced cell arrest at G0/G1 phase. Furthermore, Western blot assay showed that dual knockdown of N-ras and epiregulin markedly reduced the phosphorylations of ERK1/2, Akt and Rb, and inhibited the expression of cyclin D1. Our findings imply that multi-targeted silence of oncogenes might be an effective treatment for HCC.

c-Fos overexpression increases the proliferation of human hepatocytes by stabilizing nuclear Cyclin D1

AIM: To investigate the effect of stable c-Fos overexpression on immortalized human hepatocyte (IHH) proliferation.

METHODS: IHHs stably transfected with c-Fos (IHH-Fos) or an empty vector (IHH-C) were grown in medium supplemented with 1% serum or stimulated with 10% serum. Cell proliferation was assessed by cell counts, 3H-thymidine uptake and flow cytometry analyses. The levels of cell cycle regulatory proteins (Cyclin D1, E, A) cyclin dependent kinases (cdk) cdk2, cdk4, cdk6, and their inhibitors p15, p16, p21, p27, total and phosphorylated GSK-3β and epidermal growth factor receptor (EGF-R) were assayed by Western blotting. Analysis of Cyclin D1 mRNA levels was performed by reverse transcription-polymerase chain reaction and real-time polymerase chain reaction (PCR) analysis. Stability of Cyclin D1 was studied by cycloheximide blockade experiments.

RESULTS: Stable c-Fos overexpression increased cell proliferation under low serum conditions and resulted in a two-fold increase in [³H]-thymidine incorporation following serum addition. Cell cycle analysis by flow cytometry showed that c-Fos accelerated the cell cycle kinetics. Following serum stimulation, Cyclin D1 was more abundantly expressed in c-Fos overexpressing cells. Cyclin D1 accumulation did not result from increased transcriptional activation, but from nuclear stabilization. Overexpression of c-Fos correlated with higher nuclear levels of inactive phosphorylated GSK-3β, a kinase involved in Cyclin D1 degradation and higher levels of EGF-R mRNA, and EGF-R protein compared to IHH-C both in serum starved, and in serum stimulated cells. Abrogation of EGF-R signalling in IHH-Fos by treatment with AG1478, a specific EGF-R tyrosine kinase inhibitor, prevented the phosphorylation of GSK-3β induced by serum stimulation and decreased Cyclin D1 stability in the nucleus.

CONCLUSION: Our results clearly indicate a positive role for c-Fos in cell cycle regulation in hepatocytes. Importantly, we delineate a new mechanism by which c-Fos could contribute to hepatocarcinogenesis through stabilization of Cyclin D1 within the nucleus, evoking a new feature to c-Fos implication in hepatocellular carcinoma.

[Molecular pathogenesis of hepatocellular carcinoma: new therapeutic approaches and predictive pathology]

Hepatocellular carcinoma is one of the most prevalent malignancies worldwide and its incidence is increasing. Multimodal strategies directed towards this carcinoma include primary (e.g. immunisation) and secondary (e.g. antiviral therapy) prevention, surgical approaches, novel specific systemic therapies (targeted therapy), and the treatment of comorbidity (cirrhosis). New molecular approaches are currently under development. These tackle several specific targets, with pathology being challenged in many aspects: experimental evaluation, the development of valid tumor-relevant diagnostic tests as well as morphological evaluation in the context of clinical studies, and finally in routine diagnosis.

Antitumor and antiangiogenic activities of anti-vascular endothelial growth factor hairpin ribozyme in human hepatocellular carcinoma cell cultures and xenografts

AIM: To study the effectiveness and mechanisms of anti- human vascular endothelial growth factor (hVEGF) hairpin ribozyme on angiogenesis, oncogenicity and tumor growth in a hepatocarcinoma cell line and a xenografted model.

METHODS: The artificial anti-hVEGF hairpin ribozyme was transfected into hepatocarcinoma cell line SMMC-7721 and, subsequently, polymerase chain reaction (PCR) and reverse transcription polymerase chain reaction (RT-PCR) were performed to confirm the ribozyme gene integration and transcription. To determine the effects of ribozyme ,VEGF expression was detected by semiquantitative RT-PCR and enzyme liked immunosorbent assay (ELISA). MTT assay was carried out to measure the cell proliferation. Furthermore,the transfected and control cells were inoculated into nude mice respectively, the growth of cells in nude mice and angiogenesis were observed.

RESULTS: VEGF expression was down-regulated sharply by ribozyme in transfected SMMC-7721 cells and xenografted tumor. Compared to the control group, the transfected cells grew slower in cell cultures and xenografts, and the xenograft formation was delayed as well. In addition, the microvessel density of the xenografted tumor was obviously declined in the transfected group. As demonstrated by microscopy,reduction of VEGF production induced by ribozyme resulted in a significantly higher cell differentiation and less proliferation vigor in xenografted tumor.

CONCLUSION: Anti-hVEGF hairpin ribozyme can effectively inhibit VEGF expression and growth of hepatocarcinoma in vitro and in vivo. VEGF is functionally related to cell proliferation, differentiation and tumori-genesis in hepatocarcinoma.

Overexpression of KIAA0101 predicts high stage, early tumor recurrence, and poor prognosis of hepatocellular carcinoma

PURPOSE

KIAA0101 is a proliferating cell nuclear antigen-associated factor and involved in cell proliferation. This study is to elucidate its role in the progression, early tumor recurrence (ETR), and prognosis of hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

KIAA0101 mRNA was measured by reverse transcription-PCR in 216 resected, unifocal, primary HCCs and its protein in 164 cases by immunohistochemistry.

RESULTS

KIAA0101 mRNA was overexpressed in 131 (61%) HCCs, and protein was detected in 105 (64%). KIAA0101 mRNA overexpression correlated with higher tumor grade (P = 0.0001), higher tumor stage with vascular invasion and various extents of intrahepatic spread (P = 1 x 10(-8)), ETR (P = 1.8 x 10(-6)), and lower 5-year survival (P = 0.0026). Multivariate analysis confirmed that KIAA0101 overexpression was an independent risk factor associated with high-grade tumor (P = 0.0001), high-stage tumor (P < 0.0001), and ETR (P = 0.0052) and thus contributed to poor prognosis. KIAA0101 protein-positive tumor cells accumulated at the borders of tumor macro-trabeculae and were more abundant in tumor thrombi than in the main tumors. Hence, KIAA0101 may contribute to growth advantage and resistance to hypoxic insult. In this series, p53 mutation was detected in 93 of 184 (51%) HCCs. In both p53-mutated and non-p53-mutated HCCs, KIAA0101 overexpression correlated with higher vascular invasion (stages IIIA to IV; all Ps < 0.0001) and, accordingly, led to lower 5-year survival rates (P = 0.011 and 0.029, respectively).

CONCLUSION

KIAA0101 correlates with enhanced metastatic potential and is a significant prognostic factor of HCC.

Application of doxorubicin-induced rAAV2-p53 gene delivery in combined chemotherapy and gene therapy for hepatocellular carcinoma

p53 gene transfer has been proposed as a potential therapeutic option for treatment of hepatocellular carcinoma (HCC). Compared to other commonly used gene transfer vectors such as adenovirus and retrovirus, recombinant adeno-associated virus serotype 2 (rAAV2) has shown promising results in human clinical trials. Significant enhancement in the gene transfer efficiency is needed, however, for HCC applications. In the present study, we applied chemotherapy drug Doxorubicin (DOX) to induce rAAV2 transduction of hepatomas. Using reporter assays, we showed that the DOX-treated hepatomas became more susceptible to rAAV2 infection in comparison to untreated controls: the permissiveness increased >350-fold and >120-fold for HepG2 (p53 wild-type) and Hep3B (p53 null) hepatomas, respectively. Using the induced permissiveness, we applied rAAV2-p53 transduction to restore p53 expression in the p53-null Hep3B hepatomas. Compared to rAAV2-p53 transduction alone, rAAV2-p53 transduction with DOX resulted in a >16-fold induction of p53 expression. The transduced Hep3B expressed as much as 380% more immunoreactive p53 in comparison to the wild-type p53 expression in the HepG2 hepatomas. Significantly, when Hep3B cells were treated with 0.5 muM of DOX and rAAV2-p53 (MOI = 10) for twelve hours, the cell viability dropped to 66% four days after the administration. This decrease in cell viability was similar to that of treatment with 1 microM of DOX alone in the absence of rAAV2. The 50% reduction in DOX administration--from 1 microM to 0.5 microM--revealed the antitumor property of the rAAV2-p53 transduction as well as the joint cytotoxicity of DOX and rAAV2-p53 against the p53-null hepatomas. We conclude that DOX mediates the enhancement effect on rAAV2 transduction of human hepatomas. Combined DOX and rAAV2-p53 administration may facilitate more efficient treatment for the HCC caused by p53 mutations.

Immunohistochemical analysis of p53, cyclinD1, RB1, c-fos and N-ras gene expression in hepatocellular carcinoma in Iran

AIM: To study the effect of some genes especially those involved in cell cycle regulation on hepatocellular carcinoma.

METHODS: Paraffin-embedded tissue samples of 25 patients (18 males and 7 females) with hepatocellular carcinoma were collected from 22 pathology centers in Tehran during 2000-2001, and stained using immunohistochemistry method (avidin-biotin-peroxidase) for detection of p53, cyclinD1, RB1, c-fos and N-ras proteins.

RESULTS: Six (24%), 5 (20%), 12 (48%) and 2 samples (8%) were positive for p53, cyclinD1, C-fos and N-ras expression, respectively. Twenty-two (88%) samples had alterations in the G1 cell-cycle checkpoint protein expression (RB1 or cyclinD1). P53 positive samples showed a higher (9 times) risk of being positive for RB1 protein than p53 negative samples. Loss of expression of RB1 in association with p53 over-expression was observed in 4 (66.7%) of 6 samples. Loss of expression of RB1 was seen in all cyclinD1 positive, 20 (90.9%) N-ras negative, and 11 (50%) C-fos positive samples, respectively. CyclinD1 positive samples showed a higher (2.85 and 4.75 times) risk of being positive for c-fos and N-ras expression than cyclinD1 negative samples.

CONCLUSION: The expression of p53, RB1 and c-fos genes appears to have a key role in the pathogenesis of hepatocellular carcinoma in Iran. Simultaneous overexpression of these genes is significantly associated with their loss of expression during development of hepatocellular carcinoma.

Is there a role for immunotherapy in hepatocellular carcinoma?

Incidence of hepatocellular carcinoma has been rising in the last two decades because of the wide exposure to hepatitis C virus during 1960s and 1970s. Improvement in treatment has been achieved by local ablative therapies, however because of early recurrence and lack of effective chemotherapies, alternative treatments based on stimulation of the anti-tumour immune response could represent new strategies to control hepatocellular carcinoma spread and recurrence. Proof of principle of an effective immunotherapy has been achieved for other solid tumours such as melanoma and several results could be transferred to the immunotherapy of hepatocellular carcinoma. Specific tumour antigens have been identified in hepatocellular carcinoma, such as cancer testis antigens expressed in a large part of hepatocellular carcinomas and alpha-fetoprotein that has been already employed in clinical trials demonstrating immunogenicity without however significant clinical efficacy. Better results have been achieved by non-antigen-specific immunotherapies that demonstrated improvement in recurrence and recurrence-free survival in patients undergoing surgical resection for hepatocellular carcinoma. Passive immunotherapy and targeted therapies blocking tumour cell receptors or enzymatic pathways are already in the clinic for other malignancies and the near future will see these new treatments applied to hepatocellular carcinoma patients along with the development of efficacious active immunotherapies aimed at reducing disease recurrence and improving survival.

Opposite roles of human pancreatitis-associated protein and REG1A expression in hepatocellular carcinoma: association of pancreatitis-associated protein expression with low-stage hepatocellular carcinoma, beta-catenin mutation, and favorable prognosis

PURPOSE

Pancreatitis-associated protein (PAP) and regenerating protein 1 alpha (Reg1A) are up-regulated during the pancreas regeneration. This study is to investigate the clinicopathologic denotation of their expression in hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

PAP and REG1A mRNA levels were measured in 265 surgically removed unifocal primary HCCs using reverse transcription-PCR.

RESULTS

PAP and REG1A mRNAs were detected in 97 (36.6%) and 55 (20.8%) HCCs, respectively, including 46 with coexpression but in none of the 219 nontumorous livers. HCCs with PAP expression correlated with low-stage tumors without evidence of vascular invasion (P = 0.013) but the REG1A expression did not. By a combination analysis, HCCs with PAP expression alone showed the lowest frequency of p53 mutation (P < 0.036), the highest rates of grade 1 and low-stage tumors (P < 0.007 and P < 0.001, respectively), less frequent early tumor recurrence (P = 0.051), and hence a better 5-year survival (P = 0.044) than groups expressing PAP and REG1A, REG1A alone, and neither PAP or REG1A. Besides, PAP expressing HCCs had significantly frequent beta-catenin mutation, regardless of REG1A expression, P < 0.00001. In the subset of HCCs that has no mutations of p53 and beta-catenin but showed PAP expression, coexpression of REG1A and PAP was associated with more frequent vascular invasion than PAP expression alone (P < 0.005).

CONCLUSIONS

These data suggest that PAP expression designate a subset of low-grade, low-stage HCC with frequent beta-catenin mutation and hence more favorable prognosis, whereas further genetic or epigenetic alterations, such as p53 mutation and REG1A expression, lead to more advanced HCCs.

Activation of the canonical Wnt/beta-catenin pathway confers growth advantages in c-Myc/E2F1 transgenic mouse model of liver cancer

BACKGROUND/AIMS

Previously, we showed that activation of the beta-catenin/Wnt pathway is a dominant event during c-Myc/E2F1 hepatocarcinogenesis. Majority of c-Myc/E2F1 HCCs displayed nuclear accumulation of beta-catenin in the absence of beta-catenin mutations, suggesting that alterations in other members of the Wnt pathway might be responsible for nuclear localization of beta-catenin. Here, we investigated the mechanisms responsible for nuclear translocation of wild-type beta-catenin and addressed the potential contribution of the Wnt pathway in c-Myc/E2F1 hepatocarcinogenesis.

METHODS

Status of the members of the Wnt pathway was determined through microsatellite and Western blot analysis.

RESULTS

Majority of c-Myc/E2F1 HCCs exhibited multiple abnormalities in the Wnt pathway regardless of the presence of beta-catenin mutations. The observed abnormalities included overexpression of Wnt-1, Frizzled 1 and 2 receptors, Dishevelled-1, downregulation of Secreted frizzled-related protein-1, GSK-3beta inactivation, microsatellite instability at the Axin locus as well as induction of beta-catenin target genes, such as glutamine synthetase, glutamate transporter-1, and Wisp-1. HCCs with beta-catenin activation displayed significantly higher proliferation rate and larger tumor size when compared with beta-catenin negative tumors.

CONCLUSIONS

The data demonstrate that multiple abnormalities in the members of the Wnt pathway lead to nuclear accumulation of beta-catenin and suggest that activation of Wnt pathway provides proliferative advantages in c-Myc/E2F1-driven hepatocarcinogenesis.

Diabetes status and post-load plasma glucose concentration in relation to site-specific cancer mortality: findings from the original Whitehall study

OBJECTIVE

While several studies have reported on the relation of diabetes status with pancreatic cancer risk, the predictive value of this disorder for other malignancies is unclear.

METHODS

The Whitehall study, a 25 year follow-up for mortality experience of 18,006 men with data on post-challenge blood glucose and self-reported diabetes, allowed us to address these issues.

RESULTS

There were 2158 cancer deaths at follow-up. Of the 15 cancer outcomes, diabetes status was positively associated with mortality from carcinoma of the pancreas and liver, while the relationship with lung cancer was inverse, after controlling for a range of potential covariates and mediators which included obesity and socioeconomic position. After excluding deaths occurring in the first 10 years of follow-up to examine the effect of reverse causality, the magnitude of the relationships for carcinoma of the pancreas and lung was little altered, while for liver cancer it was markedly attenuated.

CONCLUSIONS

In the present study, diabetes status was related to pancreatic, liver, and lung cancer risk. Cohorts with serially collected data on blood glucose and covariates are required to further examine this area.

Expression of NGF in hepatocellular carcinoma cells with its receptors in non-tumor cell components

Nerve growth factor (NGF) is suggested to have a role in tumor progression in addition to its role in differentiation and survival of neuronal cells. We investigated expression of NGF and its receptors, TrkA and p75NTR, in hepatocellular carcinomas (HCCs). Although hepatocytes and hepatic stellate cells (HSCs) showed respectively weak and intense NGF immunostaining in the background livers of patients suffering from liver cirrhosis (LC) or chronic hepatitis (CH), intense staining was demonstrated in HCC cells of 33 of 54 (61.1%) tumors. RT-PCR detected NGF mRNA in 7 freshly-isolated HCC samples, and in 2 of 4 cases, in which both background livers and tumors could be analyzed, NGF mRNA was more abundant in the tumors than the background livers. TrkA was detected in the smooth muscle cells of hepatic arteries, but it was negative in tumor cells as well as non-neoplastic hepatocytes. p75NTR and alpha-smooth muscle actin (alphaSMA) was expressed in HSCs in the background liver and fibroblast-like cells in stromal septa, whereas HSCs within the HCC tissues were mostly negative for p75NTR but positive for alphaSMA. This suggests that HSCs in HCC have a different property from those in background livers. Furthermore, the stromal septa contained abundant nerve fibers, which may be related to the increased NGF expression in HCC cells. NGF and its receptors are then thought to have a role in cellular interactions involving HCC cells, HSCs, arterial cells and nerve cells in HCC tissues.

Molecular mechanisms in hepatocellular carcinoma development

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world. It usually develops in patients with chronic viral hepatitis, aflatoxin exposure, or excessive alcohol use. Most patients with HCC present with advanced disease and have a poor prognosis. The implementation of antiviral drugs and the availability of a vaccine for hepatitis B should help reduce the incidence of HCC. Considerable effort has now focused on unraveling the molecular pathogenesis of HCC in order to design better treatments, or to prevent the disease altogether. However, so far, the pathogenesis of HCC appears to be quite heterogeneous among patients. In particular, several mechanisms of tumorigenesis seem to be involved, including loss of tumor suppressor gene function, oncogene activation, direct viral effects, DNA methylation, and angiogenesis. It is not clear which events are critical in tumor initiation versus tumor progression. RNA expression arrays and proteomics hold promise to provide further clues about this common and complex cancer.

Reduction of double-stranded RNA-activated protein kinase in hepatocellular carcinoma associated with hepatitis B virus

Chronic hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC) in Asia. Double-stranded RNA (dsRNA)-activated protein kinase (PKR) is an interferon-induced, serine/threonine protein kinase. Recent studies have suggested that PKR is involved in the pathogenesis of HCC with hepatitis virus C infection by inhibiting viral and cellular proteins related to cell growth and proliferation. In the present study, PKR was examined in both tumor and non-tumor tissues from HCC livers infected with HBV. The expression of PKR was determined by TaqMan real-time PCR and immunohistochemical methods. The level of PKR was also analyzed in relation to pathological changes observed in HCC. The result showed that PKR was reduced in tumor tissues of HCC from HBV carriers with low serum viral load (<0.7 x 10(6) copies/ml) compared to those with higher serum viral load. However, the overall PKR level was much lower in tumor tissues than that in non-tumor tissues, irrespective of HBV carrier status or serum viral load. PKR level tended to be lower in HCC samples with alpha-fetoprotein (AFP) more than 500 ng/ml (mean: 4024.2 ng/ml) than those with AFP less than 500 ng/ml (mean: 50.6 ng/ml). There was no significant difference in the expression of PKR between tumor tissues with well differentiation and those with poor or moderate differentiation. In conclusion, the level of PKR was reduced in HCC tumor tissues, suggesting a possible role of PKR in promoting the growth of tumor. HBV may participate in altering the level of PKR, but factors other than HBV should play a more determining role in the regulation of PKR in HCC. The association between PKR and AFP levels may offer an alternative tumor marker for HCC.

Beta-catenin mutations in liver tumors induced by 2-amino-3,4-dimethylimidazo[4,5-f]quinoline in CDF1 mice

Heterocyclic amines are potent mutagens and carcinogens formed in cooked protein rich foods. In this study, we screened liver tumors induced by 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) in CDF1 mice for beta-catenin and APC mutations and other genetic alterations shown to occur in human hepatocellular carcinomas (HCC), including mutations in the p53 and H-ras genes, c-myc amplification and E-cadherin promoter methylation. SSCP followed by direct DNA sequencing revealed mutations in exon 2 of the beta-catenin gene in 2 of 16 liver tumors (12.5%). Promoter methylation of the E-cadherin gene was detected in one liver tumor induced by MeIQ. There were no mutations in the mutation cluster region of the APC gene, in exons 5-8 of the p53 gene, or in codons 12, 13 and 61 of the H-ras gene, nor c-myc amplification in any of liver tumors induced by MeIQ. These data indicate that except for the occasional disruption of the Wnt pathway through beta-catenin mutations, the genetic pathways involved in the development of HCC differ significantly between human liver cancer and tumors induced in mice by MeIQ, but do not rule out the possibility that heterocyclic amines constitute a carcinogenic risk factor in humans.

TP53 and liver carcinogenesis

Primary hepatocellular carcinoma (HCC) is one of the most common malignancies and has the fourth highest mortality rate worldwide. The major risk factors, including chronic infections with the hepatitis B or C virus, are exposure to dietary aflatoxin B1(AFB1), vinyl chloride, or alcohol consumption. Southern China and sub-Saharan Africa have the highest dietary AFB1 exposure, making it and hepatitis B virus (HBV) the major causes of cancer mortality in these geographic areas. Recent studies have discovered genetic and epigenetic changes involved in the molecular pathogenesis of HCC, including somatic mutations in the p53 tumor suppressor gene (TP53). AFB1 induces typical G:C to T:A transversions at the third base in codon 249 of p53. Chronic active hepatitis B and C (HCV) infection, and further inflammatory and oxyradical disorders including Wilson disease (WD) or hemochromatosis, generate reactive oxygen/nitrogen species that can damage DNA and mutate the p53 gene. The X gene of HBV (HBx) is the most common open reading frame integrated into the host genome in HCC. The integrated HBx is frequently mutated and has a diminished ability to function as a transcriptional cotransactivator and to activate the NF-kappa B pathway. However, the mutant HBx proteins still retain their ability to bind to and abrogate p53-mediated apoptosis. In summary, both viruses and chemicals are implicated in the etiology and molecular pathogenesis of HCC. The resultant molecular changes in the ras and Wnt signal-transduction pathways, and the p53 and Rb tumor suppressor pathways significantly contribute to liver carcinogenesis

E2F1 blocks and c-Myc accelerates hepatic ploidy in transgenic mouse models

Previously, we have shown that over-expression of either E2F1 or c-Myc promotes hepatocarcinogenesis and that E2F1 mice acquire HCC more rapidly than c-Myc transgenic mice. We also found that co-expression of E2F1/c-Myc further accelerates liver cancer development. Here we describe that the deregulated expression of these two transcription factors also affects hepatic ploidy during post-natal liver growth and before the onset of tumors. Oncogenic activity of E2F1 and/or c-Myc was associated with a persistent increase in hepatocyte proliferation. However, E2F1-mediated cell proliferation favored the predominance of diploid cells characteristic of pre-neoplastic type of liver growth whereas c-Myc functioned to accelerate age-related hepatocyte polyploidization. Similarly, proliferative advantage conferred by co-expression of E2F1 and c-Myc increased the frequency of diploid cells at a young age. Thus, the opposing effects of E2F1 and c-Myc on hepatocyte ploidy suggest that these two transcription factors have different mechanisms by which they control liver proliferation/maturation and ultimately, carcinogenesis.

Relevance of hepatic preneoplasia for human hepatocarcinogenesis

Different lesions have been suggested to represent preneoplastic conditions in human liver. They include liver cell dysplasia, separated in large-cell change (LCC) and small-cell change (SCC), adenomatoid hyperplasia, and the more recently identified foci of altered hepatocytes (FAH) and nodules of altered hepatocytes (NAH). FAH have been demonstrated to represent preneoplastic lesions in various animal models of hepatocarcinogenesis. To demonstrate prevalence and significance of FAH in the human liver, the cellular composition, size distribution, and proliferation kinetics of these lesions were studied in 163 explanted and resected human livers with or without hepatocellular carcinoma (HCC). FAH including glycogen-storing foci (GSF), mixed cell foci (MCF), and basophilic cell foci were found in 84 of 111 cirrhotic livers, demonstrating higher incidences in cases with than without HCC. MCF, predominant in cirrhotic livers of the high-risk group, were more proliferative, larger and more often involved in formation of NAH than GSF. The results suggest that the FAH are preneoplastic lesions, MCF being more advanced than GSP. We also investigated the relationship of FAH to liver cell dysplasia. Occurrence of SCC, rather than that of LCC, confers FAH an increased proliferation activity and higher risk to nodular transformation, and, hence, should be considered a precancerous condition. Histological detection of FAH and SCC through needle-aspiration liver biopsy can be used for monitoring HCC development in high-risk populations, such as HBV carriers with chronic hepatitis and/or cirrhosis.

The significance of immunohistochemistry in the diagnosis and therapy of neoplasms

This review article details the diagnostical significance of immunohistochemistry, which has developed during the last quarter of the century. Certainly, the advancement of monoclonal antibody technology has been of great significance in assuring the place of immunohistochemistry in the modern accurate microscopic diagnosis of human neoplasms, as a method of choice in histopathology. The fact still remains that in order to properly assess any immunohistochemical reactivity used for differential diagnostic purposes, the target cells have to be identified as neoplastically transformed cells by routine histopathological techniques. Selected groups of target molecules of great significance in cancer biology are discussed. The discovery of neoplasm-associated antigens has not only made the more accurate diagnosis of human cancer feasible but has also shed light on the extensive immunophenotypical heterogeneity of even the most closely linked human malignancies. The identification of disseminated neoplastically transformed cells by immunohistochemistry has allowed for a clearer picture of cancer invasion and metastasis, as well as the evolution of the tumour cell associated immunophenotype towards increased malignancy. Some possibilities of neoplasm-associated antigen targeted, receptor-directed immunotherapy are discussed and reviewed in this manuscript. Future antineoplastic therapeutical approaches should see the inclusion of a variety of immunotherapies, in the form of an individualised 'cocktail' specific for the particular immunophenotypical pattern associated with each individual patient's neoplastic disease.

Immunotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death, with over a million new cases annually. It is generally advanced upon detection due to underlying liver disease, which further complicates treatment. Most of the therapeutic strategies in current use (surgery, transplantation, irradiation or chemotherapy) are either palliative or only of benefit to a small percentage of patients. This article reviews the biology of HCC, including many of the molecular changes and mechanisms leading to HCC development. This article discusses the recent innovative strategies to interfere with the progression of HCC, including novel gene therapy strategies. The most recent data supporting the use of immunotherapy for hepatocellular cancer is reviewed in detail.

Increase in de novo HBV DNA integrations in response to oxidative DNA damage or inhibition of poly(ADP-ribosyl)ation

Chronic infection with hepatitis B virus (HBV) is associated with an increased risk for the development of cirrhosis and hepatocellular carcinoma (HCC). Although clonal HBV DNA integrations are detected in nearly all HCCs the role of these integrations in hepatocarcinogenesis is poorly understood. We have used a cloning protocol that allows studying the frequency and the natural history of HBV DNA integrations in cell culture. Southern blot analysis of the genomic DNA of HepG2 2.2.15 subclones, which replicate HBV, enabled us to detect new HBV DNA integrations in approximately 10% of the HepG 2.2.15 subclones over 4 rounds of sequential subcloning, whereas no loss of any preexisting HBV DNA integrations was observed. Treatments of HepG2 cells with H(2)O(2), designed to increase DNA damage, increased the frequency of HBV integrations to approximately 50% of the subclones and treatments designed to inhibit DNA repair, by inhibiting Poly(ADP-ribosyl)ation, also increased the frequency of HBV integration to 50%. These findings suggest that DNA strand breaks induced by oxidative stress during persistent HBV infection in humans may increase HBV DNA integration events, whereas PARP-1 activity may function to limit the occurrence of de novo HBV DNA integrations.

The role of diabetes in hepatocellular carcinoma: a case-control study among United States Veterans

OBJECTIVE

Diabetes mellitus (DM) has been reported to increase the risk of hepatocellular carcinoma (HCC). We carried out a case-control study to examine the role of DM while controlling for several known risk factors of HCC.

METHODS

All hospitalized patients with primary liver cancer (PLC) during 1997-1999 were identified in the computerized database of the Department of Veterans Affairs, the Patient Treatment File. Controls without cancer were randomly assigned from the Patient Treatment File during the same time period. The inpatient and outpatient files were searched for several conditions including DM, hepatitis C virus (HCV), hepatitis B virus (HBV), alcoholic cirrhosis, autoimmune hepatitis, hemochromatosis, and nonspecific cirrhosis. Adjusted odds ratios (OR) were calculated in a multivariable logistic regression model.

RESULTS

We identified 823 patients with PLC and 3459 controls. The case group was older (62 yr [+/-10] vs 60 [+/-11], p < 0.0001), had more men (99% vs 97%, 0.0004), and a greater frequency of nonwhites (66% vs 71%, 0.0009) compared with controls. However, HCV- and HBV-infected patients were younger among cases than controls. Risk factors that were significantly more frequent among PLC cases included HCV (34% vs 5%, p < 0.0001), HBV (11% vs 2%, p < 0.0001), alcoholic cirrhosis (47% vs 6%, p < 0.0001), hemochromatosis (2% vs 0.3%, p < 0.0001), autoimmune hepatitis (5% vs 0.5%, p < 0.0001), and diabetes (33% vs 30%, p = 0.059). In the multivariable logistic regression, diabetes was associated with a significant increase in the adjusted OR of PLC (1.57, 1.08-2.28, p = 0.02) in the presence of HCV, HBV, or alcoholic cirrhosis. Without markers of chronic liver disease, the adjusted OR for diabetes and PLC was not significantly increased (1.08, 0.86-1.18, p = 0.4). There was an increase in the HCV adjusted OR (17.27, 95% Cl = 11.98-24.89) and HBV (9.22, 95% CI = 4.52-18.80) after adjusting for the younger age of HCV- and HBV-infected cases. The combined presence of HCV and alcoholic cirrhosis further increases the risk with an adjusted OR of 79.21 (60.29-103.41). The population attributable fraction for HCV among hospitalized veterans was 44.8%, whereas that of alcoholic cirrhosis was 51%.

CONCLUSION

DM increased the risk of PLC only in the presence of other risk factors such as hepatitis C or B or alcoholic cirrhosis. Hepatitis C infection and alcoholic cirrhosis account for most of PLC among veterans.

Transgenic targeting of a dominant negative corepressor to liver blocks basal repression by thyroid hormone receptor and increases cell proliferation

Unliganded thyroid hormone receptors (TRs) interact with corepressors and repress basal transcription of target genes in cotransfection and in vitro studies. Currently, little is known about the function of corepressors in vivo. We thus used a mouse albumin promoter to generate several transgenic mouse lines that overexpressed a dominant negative mutant corepressor, NCoRi, in liver. The transgenic mice had normal liver weight, appearance, and minimal changes in enzyme activity. To study the effects of NCoRi on transcription of hepatic target genes, we examined T3-regulated gene expression of hypo- and hyperthyroid transgenic mice. In hypothyroid mice, hepatic expression of Spot 14, Bcl-3, glucose 6-phosphatase, and 5'-deiodinase mRNA was higher in transgenic mice than littermate controls whereas these genes were induced to similar levels in T3-treated mice. Derepression was not observed for malic enzyme mRNA expression in hypothyroid mice. Thus, NCoRi selectively blocked basal transcription of several thyroid hormone-responsive genes but had no effect on ligand-mediated transcription. Additionally, compensatory increases in endogenous SMRT and NCoR mRNA were observed in hypothyroid transgenic mice. Interestingly, hepatocyte proliferation as detected by BrdUrd incorporation was increased in transgenic mice. The gene profile in transgenic mouse livers was studied by cDNA microarray, and several genes related to cell proliferation were induced. In summary, our studies show that NCoR plays important roles in mediating basal repression by TRs and may prevent cellular proliferation in vivo.

HLA class II alleles in Chinese patients with hepatocellular carcinoma

BACKGROUND/AIMS

Recent reports of an association between human leucocyte antigens (HLA) and persistence of hepatitis B virus infection, and the familial clustering of hepatocellular carcinoma raise the question of genetic susceptibility. Previous studies have been limited to serological phenotyping of HLA B and DR antigens. The aim of this study was to use molecular genotyping to investigate HLA class II as a risk factor for the development of hepatocellular carcinoma in Hong Kong Chinese.

METHODS

We determined HLA DRB1, DQA1, DQB1 and DPB1 alleles in 123 hepatitis B surface antigen positive patients (84 with hepatocellular carcinoma and 39 without) and 124 matched controls.

RESULTS

The alleles DRB1*1501 (36% of HCC patients versus 19% of controls, odds ratio=2.44), DQA1*0102 (42% versus 26%, odds ratio=2.07), and DPB1*0501 (80% versus 63%, odds ratio=2.35) were significantly more common in patients with hepatocellular carcinoma, and DQA1*03 (36% versus 56%, odds ratio=0.53), DQB1*0302 (4.% versus 13%, odds ratio=0.25) and DPB1*0201 (14% versus 29%, odds ratio=0.4) were found at significantly lower frequencies.

CONCLUSIONS

Although none of these associations was significant after correction for multiple testing, this report suggests that further investigations are warranted.

Human hepatocellular carcinoma is characterized by a highly consistent pattern of genomic imbalances, including frequent loss of 16q23.1-24.1

Comparative genomic hybridization (CGH) analysis was used to identify chromosomal imbalances in 52 human primary hepatocellular carcinomas (HCCs). The most prominent changes were gains of part or all of chromosome arms 8q (83% of cases) and 1q (73%) and loss of 16q (63%). Other commonly overrepresented sites were 5p, 7q, and Xq. Recurrent sites of DNA sequence amplification included 8q23--24 (five cases) and 11q13--14 (four cases). Other frequently underrepresented sites were 4q, 8p, 16p, and 17p. Taken collectively, these findings and data from other CGH studies of HCCs define a subset of chromosome segments that are consistently over- or underrepresented and highlight sites of putative oncogenes and tumor suppressor genes, respectively, involved in hepatocellular oncogenesis. Loss of heterozygosity analysis with a panel of polymorphic microsatellite markers distributed along 16q defined a minimal region of chromosomal loss at 16q23.1--24.1, suggesting that this region harbors a tumor suppressor gene whose loss/inactivation may contribute to the pathogenesis of many HCCs.

Expression of c-Myc, c-Fos, and c-jun in hepatocellular carcinoma

BACKGROUND

Increased expression of the proto-oncogene c-myc is a common phenomenon in hepatocellular carcinoma (HCC). The proto-oncogenes c-fos and c-jun are involved in cell cycle progression and cellular proliferation.

METHODS

The objective of this study was to elucidate the mechanism of hepatocarcinogenesis with regard to the expressions of c-myc, c-fos, and c-jun. One hundred fifty biopsied HCC specimens were stained immunohistochemically for the above phenotypic markers both in tumor tissue and in adjacent nontumor tissue.

RESULTS

Although the expression of c-myc was high (74%) in tumor tissue, it was significantly less compared with the expression in nontumor tissue (100%; P = 0.0002). The expression of c-myc was inversely proportional to the grade of differentiation in tumor tissue (P = 0.0108; correlation coefficient [r] = -0.244); that is, tissue with poorer histologic differentiation had a lower level of c-myc expression. There were inverse associations between the expression of c-myc and the expression of mutated p53 (P = 0.0017; r = -0.285) as well as the expression of Ki67 (P = 0.057; r = -0.147). There was significantly high expression of c-fos in tumor tissue compared with the expression in nontumor tissue (91% vs. 0%; P < 0.0001). Both the tumor tissue and the nontumor tissue had high levels of expression of c-jun (96.53% and 100%, respectively). There was a trend toward a positive association between the expression of c-fos and the expression of c-jun in tumor tissue (P = 0.07; r = 0.162).

CONCLUSIONS

Because c-myc is a known inducer of wild type p53, decreased c-myc expression may lead to uncontrolled cell growth because of the lack of p53 expression that normally induces apoptosis. The coordinated expression of c-fos and c-jun in HCC may reflect the coordinated tumor cell cycle of progression and proliferation; however, future studies are required to elucidate this possibility.

Molecular cytogenetic evaluation of virus-associated and non-viral hepatocellular carcinoma: analysis of 26 carcinomas and 12 concurrent dysplasias

The worldwide incidence of hepatocellular carcinoma (HCC) is approximately one million cases a year. This makes HCC one of the most frequent human malignancies, especially in Asia and Africa, although the incidence is increasing also in the western world. HCC is a complication of chronic liver disease, with cirrhosis as the most important risk factor. Viral co-pathogenesis makes cirrhosis due to hepatitis B (HBV) and hepatitis C virus (HCV) infection a very important factor in the development of HCC. As curative therapy is often ruled out due to the late detection of HCC, it would be attractive to find parameters which predict malignant transformation in HBV- and HCV-infected livers. This study has used comparative genomic hybridization (CGH) to analyse 26 HCCs (11 non-viral, nine HBV, six HCV) and 12 concurrent dysplasias (five non-viral, five HBV, two HCV). Frequent gain (> or =25% of all tumours) was detected, in decreasing order of frequency, on 8q (69%), 1q (46%), 17q (46%), 12q (42%), 20q (31%), 5p (27%), 6q (27%), and Xq (27%). Frequent loss (> or =25% of all tumours) was found, in decreasing order of frequency, on 8p (58%), 16q (54%), 4q (42%), 13q (39%), 1p (35%), 4p (35%), 16p (35%), 18q (35%), 14q (31%), 17p (31%), 9p (27%), and 9q (27%). Minimal overlapping regions could be determined at multiple locations (candidate genes in parentheses). Minimal regions of overlap for deletions were assigned to 4p14-15 (PCDH7), 8p21-22 (FEZ1), 9p12-13, 13q14-31 (RB1), 14q31 (TSHR), 16p12-13.1 (GSPT1), 16q21-23 (CDH1), 17p12-13 (TP53), and 18q21-22 (DPC4, DCC). Minimal overlapping amplified sites could be seen at 8q24 (MYC), 12q15-21 (MDM2), 17q22-25 (SSTR2, GH1), and 20q12-13.2 (MYBL2, PTPN1). A single high level amplification was seen on 5q21 in an HBV-related tumour. Aberrations appeared more frequent in HBV-related HCCs than in HCV-associated tumours (p=0.008). This was most prominent with respect to losses (p=0.004), specifically loss on 4p (p=0.007), 16q (p=0.04), 17p (p=0.04), and 18q (p=0.03). In addition, loss on 17p was significantly lower in non-viral cancers than in HBV-related HCC (p<0.001). Furthermore, loss on 13q was more prevalent in HCCs in non-cirrhotic livers (p=0.02), thus suggesting a different, potentially more aggressive, pathway in neoplastic progression. A tendency (p=0.07) was observed for loss on 9q in high-stage tumours; no specific changes were found in relation to tumour grade. A subset of the HCC-associated genetic changes was disclosed in the preneoplastic stage, i.e. liver cell dysplasia. This group of dysplasias showed frequent gain on 17q (25%) and frequent loss on 16q (33%), 4q (25%), and 17p (25%). The majority of the dysplasias with alterations revealed genetic changes that were also present in the primary tumour. In conclusion, firstly, this study has provided a detailed map of genomic changes occurring in HCC of viral and non-viral origin, and has suggested candidate genes. Loss on 17p, including the TP53 region, appeared significantly more prevalent in HBV-associated liver cancers, whereas loss on 13q, with possible involvement of RB1, was distinguished as a possible genetic biomarker. Secondly, CGH analysis of liver cell dysplasia, both viral and non-viral, has revealed HCC-specific early genetic changes, thereby confirming its preneoplastic nature. Finally, genes residing in these early altered regions, such as CDH1 or TP53, might be associated with hepatocellular carcinogenesis.

Genes and viruses in hepatobiliary neoplasia

Hepatobiliary neoplasms comprise a significant portion of the worldwide cancer burden. Advances in basic science research have led to rapid progress in our understanding of the molecular events responsible for these dreaded diseases. The genetic changes associated with hepatocellular carcinoma (HCC) have received the most attention. Aflatoxin B1 exposure leads to mutations in the p53 tumor suppressor gene, most commonly a transversion in codon 249 that leads to a substitution of serine for arginine in the p53 protein. Numerous other tumor suppressor genes, oncogenes, and tumor gene pathways are altered in HCC. Hepatitis B virus (HBV) infection is strongly associated with HCC. HBV may cause HCC either directly via the HBV X protein, or indirectly by causing liver inflammation and cirrhosis. Hepatitis C virus (HCV) infection is also associated with HCC. Recent evidence suggests that the HCV core protein may play a role in hepatocarcinogenesis. Several inherited metabolic diseases are associated with HCC. It is likely that these diseases cause HCC indirectly by causing cirrhosis. The molecular pathogenesis of cholangiocarcinoma and gallbladder cancer has not been well defined. However, multiple tumor suppressor genes and oncogenes, including p53 and K-ras, are altered in these tumors. Further molecular characterization of hepatobiliary tumors may lead to earlier diagnosis, better staging, improved treatment planning, and the development of more effective therapies.

The role of wild-type and mutated N-ras in the malignant transformation of liver cells

In order to determine the role of N-ras overexpression and mutation in malignant liver cell transformation, wild-type and mutated N-ras were transfected into the rat liver epithelial cell line OC/CDE 22, and N-ras expression, growth kinetics, growth in soft agar, and tumorigenicity in vivo as well as the involvement of the mitogen-activated protein kinase (MAPK) signal transduction pathway in the expression of the malignant phenotype were analyzed. Although OC/CDE 22 cells transfected with wild-type N-ras showed a high expression of N-ras at the mRNA and protein levels, the cells did not grow in soft agar and were not tumorigenic in vivo. In contrast, OC/CDE 22 cells transfected with mutated N-ras showed anchorage-independent growth and were tumorigenic. When cultured in fetal bovine serum-supplemented medium, OC/CDE 22 cells expressing mutant N-ras showed a higher proliferation rate than nontransfected OC/CDE 22 cells or OC/CDE 22 cells transfected with wild-type N-ras. When held in serum-free medium, untreated OC/CDE 22 cells did not grow at all, while OC/CDE 22 cells transfected with wild-type or mutant N-ras proliferated at a similar rate, which can be explained by the high MAPK activity in these cells. Selective inhibition of the MAPK cascade abolished the growth of OC/CDE 22 cells carrying mutant N-ras in soft agar; furthermore, these cells ceased pile up and formed monolayers on Petri dishes. Thus, activation of the MAPK signaling pathway, though alone not sufficient to malignantly transform liver cells (as shown in liver cells overexpressing wild-type N-ras), is not only essential for growth control but also for the expression of the malignant phenotype (as demonstrated in liver cells transformed by mutated N-ras).

Hepatitis B virus surface (S) transactivator with DNA-binding properties

Chronic infection with hepatitis B virus (HBV) in humans is strongly linked to the development of hepatocellular carcinoma (HCC). Activation of growth-regulatory genes may play a crucial role in carcinogenesis. Proto-oncogene expression has been shown to be higher in HCC tissue with integrated HBV DNA than in the normal liver. Earlier, we showed that the 3' end of the HBV major surface gene (S) (426-855 nucleotides of the S region) is a transactivator of the X promoter-enhancer regulatory element in co-transfection experiments. This region expresses a truncated carboxy terminal S protein extending from amino acid residues 102 to 226. In this study, the truncated S protein (trc-S) was examined for its enhancing activity on several viral and cellular regulatory elements. The results indicate that trc-S activates rous sarcoma virus long terminal repeat (LTR), human T-lymphotropic virus 2 LTR, human immunodeficiency virus 1 LTR, and the c-jun and c-fos promoters. Electrophoretic mobility shift assays carried out to investigate its DNA-binding properties established that trc-S binds to HBV X promoter and oligonucleotides representing binding sites for the AP1 and TFIID transcription factors. The specificity of this interaction was confirmed by using competition experiments and supershift assays. These experiments suggest that trc-S is a transactivator of several cellular and viral promoters and that this activity is mediated by direct interaction with DNA.

P53 tumor suppressor gene mutations in hepatocellular carcinoma patients in India

BACKGROUND

Specific mutations of the p53 tumor suppressor gene in hepatocellular carcinoma (HCC) have been reported from several parts of the world, but to the authors' knowledge to date the status of this gene has not been studied in HCC patients in India, where HCC is one of the major cancers and the frequency of chronic hepatitis B virus (HBV) as well as hepatitis C virus (HCV) infection and exposure to dietary aflatoxin B(1) is very high. The most frequent mutation of the p53 gene in HCC is an AGG(Arg) to AGT(Ser) missense mutation at codon 249 of exon 7.

METHODS

Liver biopsy specimens from 21 HCC patients and 10 healthy controls were obtained through surgery or by needle biopsy technique. Phenol-chloroform-extracted DNA specimens were employed for the detection of HBV infection and p53 gene mutations. Nucleotide mutations of exons 4-9 of the p53 gene were analyzed by polymerase chain reaction (PCR), single strand confirmation polymorphism, and direct sequencing. Third-generation sandwich enzyme-linked immunosorbent assay (ELISA) was used for the serologic detection of HBV and HCV infection.

RESULTS

Analysis of exons 4-9 of the p53 gene revealed only 3 mutations (3 of 21 specimens, 14.28%; 95% confidence interval, -0.7-29.3), 2 mutations at codon 249 showing G-->T transversions, and 1 mutation (4.7%) at codon 250 with a C-->T transition. The base substitutions at the third base of codon 249 resulted in a missense mutation leading to a change in amino acid from arginine to serine whereas at codon 250 it caused a change from proline to serine. Dot blot hybridization and PCR for HBV DNA from HCCs revealed 58.8% (10 of 17 specimens) and 90. 47% (19 of 21 specimens), positivity, respectively. ELISA for hepatitis B virus surface antigen in serum showed a positivity of 71. 42% (15 of 21 specimens), but there was only 40% positivity (8 of 20 specimens) for hepatitis B virus envelope antigen whereas 6 of 17 patients (35.29%) showed the presence of antibodies against hepatitis B virus envelope protein. No patient was found to be positive for the HCV antibody.

CONCLUSIONS

The very low frequency of p53 mutations and the extremely high frequency of HBV infection (> 90%) in HCC indicate that the mutations in the p53 gene frequently found in HCC reported from different endemic areas of the world may not play a direct role in the development of HCC in India. HBV infection and, possibly, exposure to the dietary aflatoxin B(1) appear to play major roles in the molecular pathogenesis of HCC in India.