Genetic variations at loci involved in the immune response are risk factors for hepatocellular carcinoma

Primary liver cancer is the third most common cause of cancer-related death worldwide, with a rising incidence in Western countries. Little is known about the genetic etiology of this disease. To identify genetic factors associated with hepatocellular carcinoma (HCC) and liver cirrhosis (LC), we conducted a comprehensive, genome-wide variation analysis in a population of unrelated Asian individuals. Copy number variation (CNV) and single nucleotide polymorphisms (SNPs) were assayed in peripheral blood with the high-density Affymetrix SNP6.0 microarray platform. We used a two-stage discovery and replication design to control for overfitting and to validate observed results. We identified a strong association with CNV at the T-cell receptor gamma and alpha loci (P < 1 × 10(-15)) in HCC cases when contrasted with controls. This variation appears to be somatic in origin, reflecting differences between T-cell receptor processing in lymphocytes from individuals with liver disease and healthy individuals that is not attributable to chronic hepatitis virus infection. Analysis of constitutional variation identified three susceptibility loci including the class II MHC complex, whose protein products present antigen to T-cell receptors and mediate immune surveillance. Statistical analysis of biologic networks identified variation in the "antigen presentation and processing" pathway as being highly significantly associated with HCC (P = 1 × 10(-11)). SNP analysis identified two variants whose allele frequencies differ significantly between HCC and LC. One of these (P = 1.74 × 10(-12)) lies in the PTEN homolog TPTE2.

CONCLUSION

Combined analysis of CNV, individual SNPs, and pathways suggest that HCC susceptibility is mediated by germline factors affecting the immune response and differences in T-cell receptor processing.

Lamivudine plus adefovir or entecavir for patients with chronic hepatitis B resistant to lamivudine and adefovir

BACKGROUND & AIMS

Little is known about the optimal management of patients with chronic hepatitis B (CHB) who developed multiple-drug resistance.

METHODS

We assessed 91 patients with compensated CHB who developed adefovir-resistant mutations during adefovir monotherapy for lamivudine-resistant CHB. Of these, 41 were treated with a combination of lamivudine plus adefovir (LAM+ADV group) and 50 were treated with entecavir monotherapy (ETV group).

RESULTS

There were no significant differences between the two groups in baseline characteristics, including serum HBV DNA levels (p>0.05). The rate of virologic non-response (HBV DNA reduction <1 log(10) IU/ml at 6 months) was significantly greater in the LAM+ADV than in the ETV group (51.2% vs. 16.0%, p<0.01). At 12 months, HBV DNA declined less in the LAM+ADV than in the ETV group (-1.49+/-1.78 vs. -3.47+/-2.13 log(10) IU/ml, p<0.01). Only 12.2% and 22.0% of patients in the LAM+ADV and ETV groups, respectively, achieved complete virologic response (HBV DNA <60 IU/ml) at 12 months. Multivariable analysis showed that LAM+ADV group (OR=0.08, CI=0.02-0.28) and the presence of the rtA181V/T mutation (OR=0.21, CI=0.05-0.91) were independently associated with a decreased rate of virologic response (HBV DNA <2000 IU/ml) at 12 months.

CONCLUSIONS

In patients with CHB resistant to lamivudine and adefovir, combination therapy with these two drugs was not effective and was inferior to entecavir monotherapy in suppressing HBV DNA. However, the response to entecavir monotherapy was also not optimal. These results emphasize the importance of preventing the development of multidrug-resistant HBV and of exploration for adequate combination therapy in treatment of multidrug-resistant CHB.

The protease inhibitor, elafin, induces p53-dependent apoptosis in human melanoma cells

Expression of the protease inhibitor elafin is deregulated in several human cancers. However, functions of the protein in cancer are yet to be established. Here, we show that elafin elicits pro-apoptotic effects in melanoma cells but not in normal melanocytes. Elafin triggered the intrinsic apoptotic pathway as evidenced by the increased caspase 9 activity and unaltered caspase 8 activity. Caspase 9-specific siRNA, but not caspase 8-specific siRNA, dramatically abrogated elafin-induced apoptosis. Elevated level of p53 was observed, resulting in increased transcriptional activation and consequent expression of downstream effector molecules (Bax, Puma, Noxa, p21). Moreover, the apoptotic effect of elafin was inhibited by p53-specific siRNA and the p53 inhibitor pifithrin-alpha. Elafin treatment of xenograft mice of melanoma cells led to significantly smaller tumor sizes compared with those of untreated control mice. Immunohistochemical analysis revealed decreased elafin expression in melanoma tissue specimens. Western blot and reverse transcription analyses indicated transcriptional repression of the elafin gene in melanoma cells. Our results collectively indicate that elafin induces apoptosis in melanoma cells through a p53-dependent intrinsic apoptotic pathway, and that repression of elafin expression in melanoma may contribute to disease progression.

Stimulation of protein kinase C-alpha suppresses colon cancer cell proliferation by down-regulation of beta-catenin

We reported previously that protein kinase C-alpha (PKC-alpha) negatively regulates Wnt/beta-catenin signalling pathway. The current study explores the role of PKC-alpha in the regulation of proliferation of colon cancer cells, which contain aberrant up-regulation of intracellular beta-catenin. In colon tissue and cells, an inverse correlation was observed between the expression levels of PKC-alpha and intracellular beta-catenin. Activation of PKC-alpha inhibited beta-catenin response transcription by down-regulation of intracellular beta-catenin and induced phosphorylation of the N-terminal serine and threonine residues (Ser33/Ser37/Thr41) of beta-catenin, marking it for proteasomal degradation, in colon cancer cells. Pharmacological inhibition or depletion of PKC-alpha-abrogated PKC-alpha-mediated beta-catenin down-regulation and phosphorylation in colon cancer cells. Notably, the Ser45 residue of beta-catenin was essential for PKC-alpha-induced beta-catenin down-regulation in colon cancer cells. Moreover, PKC-alpha activation repressed the expression of cyclin D1 and c-myc, which are known beta-catenin target genes, and thus inhibited the growth of colon cancer cells. These findings suggest that PKC-alpha negatively regulates colon cancer cell proliferation viabeta-catenin phosphorylation/down-regulation and may facilitate the development of new strategies to treatment of colon cancer.

[Mutations within the interferon sensitivity determining region in Korean patients infected with hepatitis C virus genotype 1b]

BACKGROUND/AIMS

The treatment response to interferon could differ with mutations in the interferon-sensitivity-determining region (ISDR) in patients infected with hepatitis C virus (HCV) genotype-1b (HCV-Ib). We examined the pattern of ISDR mutations and analyzed whether the number of amino acid substitutions influences the treatment response to peginterferon plus ribavirin in chronic hepatitis or cirrhotic patients infected with HCV-Ib.

METHODS

The study population comprised 52 patients who visited Seoul Asan Medical Center and Seoul National University Bundang Hospital from January 2006 to December 2008 and who received peginterferon alpha-2a (n=37) or -2b (n=15) plus ribavirin, and whose serum was stored. We analyzed the early virologic response, end-of-treatment response, and sustained virologic response (SVR), and examined the ISDR using direct sequencing.

RESULTS

The proportions of patients with ISDR mutation types of wild (0 mutations), intermediate (1-3 mutations), and mutant (> or =4 mutations) were 50.0%, 42.3%, and 7.7%, respectively, and the corresponding SVR rates were 63%, 50%, and 67% (p>0.05). The SVR rates were 59.4% and 50.0% in patients with <2 and > or =2 mutations, respectively (p>0.05). On univariate analysis, age was the only predictive factor for SVR (p=0.016). The pretreatment HCV RNA titer tended to be lower in those with SVR, but without statistical significance (p=0.069).

CONCLUSIONS

The frequency of ISDR mutations was low in our cohort of Korean patients infected with HCV-Ib. Therefore, ISDR mutations might not contribute to the response to treatment with peginterferon plus ribavirin.

Estimation of the healthy upper limits for serum alanine aminotransferase in Asian populations with normal liver histology

A recent study in young Italian subjects suggested that the healthy thresholds for serum alanine aminotransferase (ALT) levels should be adjusted to 30 IU/L for men and 19 IU/L for women when assessing risk factors for nonalcoholic fatty liver disease. Our aim was to assess serum ALT concentrations in healthy Korean individuals and to determine the factors affecting ALT levels in these populations. We included 1,105 potential liver donors (643 men and 462 women) with biopsy-proven normal livers. Median ages were 25 years in men and 30 years in women, with a median body mass index (BMI) of 22.3 kg/m(2) in men and 21.4 kg/m(2) in women. The calculated thresholds for ALT values in these subjects were 35 IU/L for men and 26 IU/L for women. Age and BMI were independently correlated with ALT levels in both sexes, whereas serum total cholesterol concentration was significant only in men and blood glucose level only in women (P < 0.05). When we chose a subgroup of 665 individuals (346 men and 319 women) using Prati criteria, modified by the BMI cutoff points for Asians (<23 kg/m(2)), we found that the healthy ALT values were 33 IU/L for men and 25 IU/L for women. The mean ALT concentrations for subjects within the Prati criteria were significantly lower than for those outside the criteria (16.7 versus 19.5 IU/L for men, 12.8 versus 14.9 IU/L for women; P < 0.001).

CONCLUSION

The healthy ALT thresholds in biopsy-proven normal Asians were clearly lower than the previously accepted thresholds, as has also been noted in Europeans. Age, BMI, and/or other metabolic parameters significantly affect ALT levels, even in subjects with normal livers.

Reovirus infection induces apoptosis of TRAIL-resistant gastric cancer cells by down-regulation of Akt activation

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been used to treat a variety of cancer cells. However, since some gastric cancer cells are resistant to TRAIL, we explored whether reovirus induces cytolysis in TRAIL-resistant gastric cancer cells. We found that TRAIL-resistant SNU-216 gastric cancer cells were susceptible to apoptosis by reovirus infection. Furthermore, co-treatment with reovirus and TRAIL accelerated apoptosis of SNU-216 cells by down-regulation of Akt activation as assessed by a very low activation of Akt in TRAIL-sensitive SNU-668 gastric cancer cells. Inhibition of Akt signaling with wortmannin or suppression of Akt expression with sh-Akt lentivirus promoted reovirus-mediated apoptosis of SNU-216 gastric cancer cells. Reovirus infection also down-regulates the activation of signaling molecules such as Ras and ERK involved in cell proliferation and survival but not the activation of p38 MAPK involved in cellular stress. In addition, the co-treatment with reovirus and TRAIL resulted in cleavage of caspase-8, caspase-9 and Bid, leading to a decrease in the mitochondrial membrane potential, indicating that reovirus may utilize the mitochondrial intrinsic apoptotic pathway in TRAIL-resistant SNU-216 gastric cancer cells. Accordingly, we first demonstrate that reovirus infection down-regulates Akt activation, leading to apoptosis of TRAIL-resistant gastric cancer cells.

Efficacy of entecavir in treatment-naïve patients with hepatitis B virus-related decompensated cirrhosis

BACKGROUND & AIMS

The effect of entecavir (ETV) therapy on viral suppression and hepatic function in hepatitis B virus (HBV) patients with decompensated cirrhosis has not been established. We evaluated ETV as first-line monotherapy in these patients.

METHODS

We consecutively enrolled 70 HBV-infected patients with decompensated cirrhosis primarily treated with 0.5mg/day ETV, and evaluated the clinical outcomes by intention-to-treat analyses. We also compared the virological responses of 55 patients treated for 12 months (decompensated group) with those of 144 chronic hepatitis or compensated cirrhosis patients (compensated group).

RESULTS

The cumulative transplantation-free survival was 87.1% at 1year. ETV treatment for 12 months resulted in improved Child-Turcotte-Pugh (CTP) and model for end-stage liver disease (MELD) scores. Sixty-six percent (36/55) of patients achieved CTP class A and 49% (27/55) showed improvement in the CTP score of 2 points after 12 months of ETV. The 1-year cumulative rates of HBV DNA negativity and HBeAg loss were 92.3% and 54.0%, respectively, by intention-to-treat analysis. The rates of HBV DNA negativity, HBeAg seroconversion/loss and ALT normalization at month 12 were similar for the decompensated and compensated groups. Cox regression analysis showed that pretreatment HBeAg seropositivity was a negative predictor of HBV DNA clearance during ETV therapy (hazard ratio, 0.514; 95% confidence interval 0.367-0.719; p<0.001).

CONCLUSIONS

One-year initial ETV therapy was similarly effective in both compensated and decompensated liver disease HBV patients. In addition, it improved underlying liver function in decompensated patients.

Impacts of vaccination on hepatitis B viral infections in Korea over a 25-year period

BACKGROUND

Hepatitis B virus (HBV) vaccination has effectively reduced the acute and chronic infection rates in recent years. Since 1983, HBV vaccination has been recommended for all neonates in Korea.

METHODS

This article reviews the impacts of HBV vaccination throughout the past 25 years in Korea. Before the introduction of the HBV vaccination program, approximately 8% of the general Korean population tested positive for hepatitis B virus surface antigen (HBsAg).

RESULTS

The percentage of vaccinated infants has surpassed 98.9% since 1990. The HBsAg carrier rate in the general population decreased to 3.7% in 2007. In particular, the prevalence of HBsAg decreased to 0.44% in teenagers and to 0.2% in children younger than 10 years. In addition, administration of the HBV vaccine may have reduced the risk of hepatocellular carcinoma among adults. Despite the administration of hepatitis B immunoglobulin and the HBV vaccine to children with HBsAg-positive mothers, the failure rate of HBV immunoprophylaxis was 4.2% in 2008. In Korea, there have been no reported cases of HBV surface gene variants such as G145R.

CONCLUSIONS

The prevalence of HBV carriers in Korea was markedly reduced after the introduction of the universal HBV vaccination program. Korea is now classified as an area of intermediate endemicity for HBV.

Complete necrosis after transarterial chemoembolization could predict prolonged survival in patients with recurrent intrahepatic hepatocellular carcinoma after curative resection

BACKGROUND

We explored the predictors of response to transarterial chemoembolization (TACE) in patients with recurrent intrahepatic hepatocellular carcinoma (HCC) after hepatectomy and investigated the survival of these patients according to the response to TACE.

METHODS

We analyzed data from 199 consecutive HCC patients who underwent curative liver resection and who later received repeat TACE for intrahepatic HCC recurrence.

RESULTS

Of 199 patients, 139 (69.8%) achieved complete necrosis (CN) of HCC after repeated TACE (mean TACE session number, 1.3) and the other 60 (30.2%) (non-CN group) did not achieve CN. At hepatectomy, the CN group showed significantly smaller proportions of tumor capsular invasion, microvascular invasion, and pathologic tumor-node-metastasis stage III or IV HCCs. At first TACE, the CN group showed a significantly greater proportion of patients with time to recurrence > or = 1 year, Child-Pugh class A, serum alpha-fetoprotein (AFP) levels < 200 ng/mL, tumor size < 3 cm, solitary tumors, and nodular tumor types; portal vein invasion were less common than seen in the non-CN group. After multivariate analysis, tumor size < 3 cm and a single tumor at first TACE were independently related to attainment of CN after TACE. Median survival after first TACE was significantly longer in the CN group (48.9 versus 17.0 months). In a Cox regression model, CN after TACE was an independent predictor of favorable survival outcome after first TACE.

CONCLUSIONS

CN after repeat TACE for postresection intrahepatic recurrence was attained more commonly in patients with smaller tumor size and lower tumor number at first TACE and favored longer survival in recurrent patients.

Efficacy of entecavir in patients with chronic hepatitis B resistant to both lamivudine and adefovir or to lamivudine alone

Entecavir (ETV) is currently recommended as a rescue therapy purely for adefovir (ADV)-resistant chronic hepatitis B virus (HBV) infections. We evaluated the efficacy of ETV in patients who were resistant to lamivudine (LAM)/ADV sequential therapy and in those resistant to LAM monotherapy. Fifty LAM/ADV-resistant and 38 LAM-resistant patients who received ETV 1 mg/day for at least 48 weeks were enrolled. Mean baseline serum HBV DNA and alanine aminotransferase (ALT) levels were significantly lower in the LAM/ADV-resistant group, compared with the LAM-resistant group (6.90 versus 7.62 log(10) copies/mL and 102.6 versus 160.2 IU/L; both P < 0.05); hepatitis B e antigen (HBeAg) status and LAM-resistant mutation patterns were similar in the two groups. At week 48, mean reductions in HBV DNA and ALT levels were significantly less in the LAM/ADV-resistant group (-2.96 versus -4.86 log(10) copies/mL and -68.3 versus -128.9 IU/L; both P < 0.05). Achievement of undetectable HBV DNA was also less common in the LAM/ADV-resistant group (10.0% versus 34.2%; P = 0.006), although the rates of HBeAg loss and ALT normalization did not differ between the two groups. Resistance to both LAM and ADV was an independent risk factor for failure of HBV DNA negativity at week 48 (odds ratio, 0.138; P = 0.019). In both LAM/ADV-resistant and LAM-resistant groups, primary responders (> or =1 log decline in HBV DNA at week 12) achieved a significantly greater decrease in HBV DNA levels over the 48-week period, compared with primary nonresponders (-4.18 versus -0.97 and -5.37 versus -2.15 log(10) copies/mL, respectively; both P < 0.05).

CONCLUSION

The 48-week ETV treatment was less effective in LAM/ADV-resistant than in LAM-resistant patients. Continuing ETV monotherapy could be determined based on the virological response at 12 weeks in LAM/ADV-resistant patients.

Cardamonin suppresses melanogenesis by inhibition of Wnt/beta-catenin signaling

Wnt/beta-catenin signaling plays important roles in many developmental processes, including neural crest-derived melanocyte development. Here we show that cardamonin, a calchone from Aplinia katsumadai Hayata, inhibited pigmentation in melanocytes through suppression of Wnt/beta-catenin signaling pathway. Cardamonin significantly suppressed the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase, which are melanocyte differentiation-associated markers, in human normal melanocytes, thereby decreasing intracellular melanin production. In addition, cardamonin promoted the degradation of intracellular beta-catenin that was accumulated by Wnt3a-conditioned medium (Wnt3a CM) or bromoindirubin-3'-oxime (BIO), a glycogen synthase kinase-3beta (GSK-3beta) inhibitor, in HEK293 reporter cells and human normal melanocytes. Our findings indicate that cardamonin may be a potential whitening agent for use in cosmetics and in the medical treatment of hyperpigmentation disorders.

Inhibition of GSK-3beta enhances reovirus-induced apoptosis in colon cancer cells

Reovirus functions as an oncolytic agent for many types of cancer including colon cancer. Although most studies have emphasized the role of activated Ras signaling in enhancing reoviral oncolysis in susceptible cells, we note that many colon cancers also display elevated beta-catenin. Thus, it is possible that enhanced beta-catenin may augment reoviral susceptibility in colon cancer cells. To explore this hypothesis, HEK293 cells were treated with the glycogen synthase kinase (GSK)-3beta inhibitor LiCl, thereby inducing beta-catenin, followed by reoviral infection. Co-administration with LiCl indeed enhanced cell death compared to reovirus infection alone, but this was not associated with elevated reoviral replication. Similarly, HEK293 cells expressing the Frizzled-1 receptor in Wnt3a-conditioned medium also showed reovirus replication equivalent to that in cells in control medium, further suggesting that up-regulation of beta-catenin does not enhance the replication of reovirus. Instead, we observed that inhibition of GSK-3beta with LiCl decreased reovirus-induced NF-kappaB activation, leading to accelerated apoptosis via caspase 8 activation. We further found that colon cancer HCT116 cells were sensitized to apoptosis by co-treatment with reovirus and a GSK-3beta inhibitor, AR-A014418. Finally, we identified that inhibition of NF-kappaB sensitized apoptosis of HEK293 or HCT 116 cells during reovirus infection. Taken together, we propose that inhibition of GSK-3beta sensitizes reovirus-induced apoptosis of colon cancer cells by down-regulation of NF-kappaB activity, offering a potentially improved therapeutic strategy for the treatment of colon cancer.

Overexpression of metastasis-associated protein 2 is associated with hepatocellular carcinoma size and differentiation

BACKGROUND AND AIM

Metastasis is a multistep event in which neoplastic cells detach from the tumor, migrate, disseminate, extravasate, and eventually proliferate at the secondary distant sites. Hepatocellular carcinoma (HCC) is characterized by hypervascularity and frequent metastasis. Recently, metastasis-associated proteins were identified and named metastatic tumor antigens (MTA) 1, 2, and 3. They have been found to be contained in the nucleosome remodeling and histone deacetylase complex. MTA2 has been reported to interact with p53 and inhibit p53-mediated cell growth arrest and apoptosis by deacetylation. Although it has been reported that the expression of MTA1 is related to tumor progression and metastasis, it is still unclear how MTA2 is involved in HCC. In this study, we found that the overexpression of MTA2 is associated with HCC size and differentiation after hepatectomy.

METHODS

The expression of MTA2 was examined in 506 human HCC samples that underwent hepatic resection using tissue microarray. The expression of MTA2 was classified into 0, 1, 2, and 3, based on immunoreactivity.

RESULTS

The expression of MTA2 was predominantly localized to the nucleus. MTA2 was detected in 487 (96.2%) of the 506 human HCC samples. Notably, the MTA2 expression level strongly increased depending on the size and differentiation of HCC.

CONCLUSIONS

These findings indicate a tight correlation between the MTA2 expression level and HCC size and differentiation. Therefore, MTA2 might be a predictor of aggressive phenotypes and a possible target molecule for anticancer drug design in human HCC.

Hepatitis B virus with the rtL80V/I mutation is associated with a poor response to adefovir dipivoxil therapy

BACKGROUND/AIMS

Lamivudine (LAM) resistance is frequently associated with various types of genomic changes in hepatitis B virus (HBV)-DNA including YMDD mutations (rtM204V/I). We intended to examine the effects of these genotypic variants on the antiviral efficacy of adefovir dipivoxil (ADV) therapy.

METHODS

A total of 97 chronic hepatitis B (CHB) patients with YMDD mutants who had been treated with ADV for >12 months were analysed. Mutations of the entire polymerase domain of HBV were determined by direct sequencing.

RESULTS

All the 97 patients had genotype C HBV associated with rtM204V/I mutations; 63 (65%) rtM204I, 27 (28%) rtM204V and seven (7%) both. The rtL80V/I and rtL180M variants were identified in 66 (68%) and 67 (69%) patients respectively. The rtM204I and rtM204V variants were strongly associated with rtL80V/I and rtL180M respectively (P<0.01). There was no difference in antiviral response at 12 months after ADV therapy between patients in relation to the type of YMDD mutation or the presence of rtL180M. However, interestingly, after ADV therapy for 12 months, patients with rtL80V/I achieved a much smaller reduction in serum HBV-DNA titre than those without it (mean, -3.43 vs. -4.43 log(10) copies/ml; P=0.018). In addition, patients with rtL80V/I had lower rates of undetectable HBV-DNA (20 vs. 26%), alanine aminotransferase normalization (70 vs. 81%) and HBeAg loss (16 vs. 26%) than those without it, although none of these differences was statistically significant.

CONCLUSIONS

These results provide evidence that rtL80V/I variants of HBV may be associated with a poor antiviral response to ADV in CHB patients with YMDD mutants.

Antifibrogenic effects of tamoxifen in a rat model of periportal hepatic fibrosis

BACKGROUNDS/AIMS

It has been reported that tamoxifen may affect hepatoma cell growth in vitro by suppressing transforming growth factor beta-1 (TGF-beta1) expression, suggesting that tamoxifen might also retard fibrogenesis. Thus, we examined whether tamoxifen might suppress TGF-beta1 expression and consequently inhibit the process of hepatic fibrosis in vivo.

METHODS

To induce periportal hepatic fibrosis, 50 male adult Sprague-Dawley rats were injected with 0.62 mmol/kg of allyl alcohol, intraperitoneally, twice a week for 8 weeks. Hepatic fibrosis scores, intrahepatic collagen levels and plasma TGF-beta1 expression levels were evaluated in three groups of 10 rats orally administered tamoxifen at 1, 5 and 10 mg/kg, respectively, and in 20 controls. Messenger RNAs (mRNAs) encoding TGF-beta1 and TGF-beta receptors in liver tissue were semiquantified using reverse transcriptase polymerase chain reaction.

RESULTS

Hepatic fibrosis scores decreased progressively as the dose of tamoxifen increased, resulting in a significant change in rats treated with tamoxifen at 10 mg/kg compared with controls (P=0.018). Intrahepatic collagen content was significantly less in the group treated with tamoxifen at 10 mg/kg compared with the control (P=0.045). Plasma TGF-beta1 levels were also significantly lower in rats treated with tamoxifen at 10 mg/kg compared with controls (P=0.007). All three concentrations of tamoxifen tested decreased the expression levels of hepatic TGF-beta1 mRNA and type I TGF-beta receptor (TGF-beta RI) mRNA to similar extents.

CONCLUSIONS

Tamoxifen seems to inhibit the process of hepatic fibrosis dose-dependently by suppressing the transcription of TGF-beta1 and TGF-beta RI in an experimental model of periportal hepatic fibrosis.

Hexachlorophene suppresses beta-catenin expression by up-regulation of Siah-1 in EBV-infected B lymphoma cells

Many studies have shown that the activation of β-catenin signaling can promote oncogenesis, and it is therefore of interest to find agents that modulate this pathway. Recent work has shown using B lymphoma cells that infection by Epstein–Barr virus (EBV) and expression of its latent membrane protein (LMP)-1, cause increases in the expression of β-catenin and cellular transformation. Conversely, results from cell-based small molecule screening studies have shown that the antibiotic hexachlorophene can down-regulate β-catenin in colon cancer cells. Here we report that hexachlorophene also counteracts the elevated β-catenin levels in EBV-infected B lymphomas. This is associated with restoration in levels of Siah-1 (an E3 ubiquitin ligase that is active in β-catenin regulation) which had been diminished by LMP-1. Our results suggest that Siah-1 is targeted by both LMP-1 and hexachlorophene with opposite effects. The hexachlorophene modulation of Siah-1 and β-catenin is independent of p53 and results in reduced expression of cyclin-D1 and c-Myc (target genes of β-catenin), leading to the growth arrest of B lymphoma cells. From these results we propose that hexachlorophene may provide a novel therapeutic strategy for EBV-infected B lymphoma cells by reducing β-catenin levels via the restoration of Siah-1.

Hepatic myelopathy as a presenting neurological complication in patients with cirrhosis and spontaneous splenorenal shunt

Hepatic myelopathy is a rare complication of chronic liver disease that is associated with extensive portosystemic shunts. The main clinical feature of hepatic myelopathy is progressive spastic paraparesis in the absence of sensory or sphincter impairment. Early and accurate diagnosis of hepatic myelopathy is important because patients with early stages of the disease can fully recover following liver transplantation. Motor-evoked potential studies may be suitable for the early diagnosis of hepatic myelopathy, even in patients with preclinical stages of the disease. Here we describe two patients who presented with spastic paraparesis associated with a spontaneous splenorenal shunt and without any previous episode of hepatic encephalopathy. One patient experienced improved neurologic symptoms after liver transplantation, whereas the other patient only received medical treatment, which did not prevent the progression of spastic paraparesis.

Evaluation of Subchronic Inhalation Toxicity of Dimethyl Disulfide in Rats

This study was carried out to investigate the potential subchronic inhalation toxicity of dimethyl disulfide (DMDS) via whole-body exposure in F344 rats. Groups of 10 rats of each sex were exposed to DMDS vapor by whole-body exposure at concentrations of 0, 5, 25, or 125 ppm for 6 h/day, 5 days/wk for 13 wk. All the rats were sacrificed at the end of treatment period. During the test period, clinical signs, mortality, body weights, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were examined. At 25 ppm, a decrease in the body weight gain, food intake, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and blood urea nitrogen (BUN) was observed in the males, but not in the females. However, at 125 ppm, a decrease in the body weight gain, food intake, and thymus weight and an increase in the weights of adrenal glands were observed in both genders. Serum biochemical investigations revealed a decrease in the AST, ALT, BUN, creatine phosphokinase (CPK), and triglyceride levels and an increase in the glucose level. In contrast, no treatment-related effects were observed in the 5 ppm group. The toxic potency of DMDS was slightly higher in males than that in females. In these experimental conditions, the target organ was not determined in rats. The no-observed-adverse-effect concentration (NOAEC) was found to be 5 ppm, 6 h/day for male rats and 25 ppm, 6 h/day for female rats.

BCAR3 regulates EGF-induced DNA synthesis in normal human breast MCF-12A cells

BCAR3 (breast cancer anti-estrogen resistance 3) is a signal transducer containing an SH2 domain, a proline/serine-rich domain and a GDP-exchange factor homologous domain, whose role in signaling pathways is currently unclear. Furthermore, BCAR3 is implicated in anti-estrogen resistance of breast cancer cells. In the present study, we investigated the functional role of BCAR3 in a mitogenic signaling pathway of EGF in non-tumorigenic human breast epithelial MCF-12A cells. Microinjection of an anti-BCAR3 antibody, siRNAs targeting BCAR3 and an SH2 domain of BCAR3 inhibited EGF-induced DNA synthesis. Direct association of BCAR3 with activated EGF receptor and Cas was observed. Lastly, microinjection of a BCAR3 expression plasmid induced DNA synthesis. These findings suggest that the BCAR3 protein, through its SH2 domain, is involved in the signaling pathways of EGF leading to cell cycle progression, and that BCAR3 itself is part of a mitogenic signaling pathway.

Neural cadherin overexpression is a predictive marker for early postoperative recurrence in hepatocellular carcinoma patients

BACKGROUND AND AIM

Recent studies have disclosed alterations in neural and/or epithelial cadherin (E-cadherin) expression in several epithelial tumors. However, the clinical relevance of these phenomena in hepatocellular carcinoma (HCC) remains to be established. In this study, we investigated the expression patterns of neural and epithelial cadherins and their clinical implications in HCC.

METHODS

Immunohistochemical staining for neural and epithelial cadherins was performed on tumor and adjacent non-tumor tissue sections of 52 HCC patients subjected to curative surgical resection. Clinical, radiological, and histopathological characteristics were analyzed, relative to the degree of neural and E-cadherin expression.

RESULTS

The neural cadherin (N-cadherin) expression was upregulated in 67% of HCC tissues, compared to adjacent non-tumoral liver tissues. Patients expressing high levels of N-cadherin experienced more frequent tumor recurrences within 2 years (50% vs 12.5%; P = 0.01) after surgical resection. Consequently, the cumulative overall survival rate tended to be lower in patients overexpressing N-cadherin (P = 0.08). The N-cadherin overexpression was the only independent predictive factor for postoperative recurrence within 2 years in both univariate and multivariate analyses (odds ratio: 8.5; 95% confidence interval: 1.625-44.46; P = 0.011). No correlation was evident between E-cadherin expression patterns and clinicopathological parameters.

CONCLUSION

The overexpression of N-cadherin is significantly related to postoperative recurrence within 2 years after surgical resection in HCC. Therefore, immunohistochemical staining for N-cadherin may be effectively applied as a predictive marker for early postoperative recurrence in HCC.

Metastatic tumor antigen 1 is closely associated with frequent postoperative recurrence and poor survival in patients with hepatocellular carcinoma

Metastatic tumor antigen 1 (MTA1) is known to play a role in angiogenic processes as a stabilizer of hypoxia-inducible factor 1-alpha (HIF1-alpha). In this study, we examined whether overexpression of MTA1 affects the recurrence of hepatocellular carcinoma (HCC) after surgical resection and the survival of the patients. A total of 506 HCC patients who underwent hepatic resection were included in the study. They were followed up for a median of 43 months (range, 1-96 months) after hepatectomy. MTA1 expression levels were determined by the proportion of immunopositive cells (none, all negative; +, <50%; ++, >50%). The relationships between MTA1 expression and the HCC histological features, the appearance of recurrent HCC after surgical resection, and the survival of the patients were examined. Eighty-eight cases (17%) of the HCCs were positive for MTA1, although the surrounding liver tissues were all negative for MTA1; 62 cases were + and 26 cases were ++. Increased MTA1 expression levels in HCC were correlated with larger tumors (P = 0.04), perinodal extension (P = 0.03), and microvascular invasion (P = 0.008). Histological differentiation had marginal significance (P = 0.056). However, there was no association between MTA1 expression and age, sex, Child-Pugh class, and capsule invasion of HCC. Interestingly, MTA1 expression levels were significantly greater in hepatitis B virus (HBV)-associated HCC compared with hepatitis C virus (HCV)-associated HCC (P = 0.017). The cumulative recurrence rates of MTA1-positive HCCs were markedly greater than those of MTA1-negative HCCs (P < 0.0001). The cumulative survival rates of patients with MTA1-positive HCCs were significantly shorter than those of patients with MTA1-negative HCCs (P < 0.0001). In conclusion, our data indicate that MTA1 is closely associated with microvascular invasion, frequent postoperative recurrence, and poor survival of HCC patients, especially in those with HBV-associated HCC.