Genotypic Variability of Hepatitis Viruses Associated With Chronic Infection and the Development of Hepatocellular Carcinoma

Pujol, Flor H.; Devesa, Marisol

doi:10.1097/01.mcg.0000170770.49394.92

Cited by 28 publications

(17 citation statements)

References 154 publications

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“…33 Because a diminished sensitivity to apoptotic stimuli is a hallmark of a transformed cell, the association of the genotype 1 with HCV-related tumors 34 might be of particular interest in the context of these results.…”

Section: Discussionmentioning

confidence: 99%

Calpain activation by hepatitis C virus proteins inhibits the extrinsic apoptotic signaling pathway #

et al. 2009

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An unresolved question regarding the physiopathology of hepatitis C virus (HCV) infection is the remarkable efficiency with which host defenses are neutralized to establish chronic infection. Modulation of an apoptotic response is one strategy used by viruses to escape immune surveillance. We previously showed that HCV proteins down-regulate expression of BH3-only Bcl2 interacting domain (Bid) in hepatocytes of HCV transgenic mice. As a consequence, cells acquire resistance to Fas-mediated apoptosis, which in turn leads to increased persistence of experimental viral infections in vivo. This mechanism might participate in the establishment of chronic infections and the resulting pathologies, including hepatocellular carcinoma. We now report that Bid is also down-regulated in patients in the context of noncirrhotic HCV-linked tumorigenesis and in the HCV RNA replicon system. We show that the nonstructural HCV viral protein NS5A is sufficient to activate a calpain cysteine protease, leading to degradation of Bid. Moreover, pharmacological inhibitors of calpains restore both the physiological levels of Bid and the sensitivity of cells toward a death receptor-mediated apoptotic signal. Finally, human HCV-related tumors and hepatocytes from HCV transgenic mice that display low Bid expression contain activated calpains. Conclusion: Calpains activated by HCV proteins degrade Bid and thus dampen apoptotic signaling. These results suggest that inhibiting calpains could lead to an improved efficiency of immune-mediated elimination of HCV-infected cells. (HEPATOLOGY 2009;50:1370-1379.)P ersistent infection with hepatitis C virus (HCV) is among the most common infectious causes of chronic liver disease. The majority of patients fail to clear the virus and become chronic carriers, with a persistent presence of detectable virus in the serum. 1 Patients with chronic hepatitis C are at risk for hepatic fibrosis, frequently culminating in hepatic cirrhosis and hepatocellular carcinoma (HCC). 2 FL-N/35 transgenic mice, with hepatocyte-targeted expression of the entire open reading frame of the genotype 1b HCV, are at risk for steatosis and hepatocellular adenoma and carcinoma. 3 We previously showed that the FL-N/35 hepatocytes are resistant to apoptosis induced by the Fas/CD95 death receptor stimulation. The lack of sensitivity to apoptotic stimulation was related to decreased expression of BH3-only Bcl2 interacting domain (Bid), a BH3-only member of the Bcl-2 family of apoptosis regulators. 4 Importantly, Bid-deficient hepatocytes are refractory to T lymphocyte-induced cell death, suggesting that apoptosis contributes to HCV persistence and, as a consequence, to liver pathologies characteristic of chronic HCV infection. 4 Here, we report that Bid is also down-regulated in the context of the subgenomic and genome-length HCV replicons and in a subset of HCV-linked human HCC.

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Section: Discussionmentioning

confidence: 99%

Calpain activation by hepatitis C virus proteins inhibits the extrinsic apoptotic signaling pathway #

et al. 2009

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“…The various HBV genotypes have different geographical distributions worldwide (6,7,(43)(44)(45). In East Asia, genotype B has been classified into genotypes Ba and Bj: genotype Bj was mainly found in Japan and genotype Ba was observed in other Asian ethnic groups (8,9,46).…”

Section: Discussionmentioning

confidence: 99%

Genotype and variations in core promoter and pre-core regions are related to progression of disease in HBV-infected patients from Northern Vietnam

Truong

Seo²,

Yano³

et al. 2007

Int J Mol Med

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Abstract.Vietnam is one of the countries with a high rate of hepatitis B virus (HBV) infection, but there are only a few reports about relation of HBV genotypes and mutations to clinical course in Northern Vietnam. The characteristics of HBV and its relationship to clinical outcome in patients from Northern Vietnam were analyzed. Serum samples were collected from 183 HBV-infected Vietnamese patients. They were clinically categorized into 4 groups: hepatocellular carcinoma (HCC), liver cirrhosis (LC), chronic hepatitis (CH), and asymptomatic carriers (ASC). HBV serology, ·-fetoprotein, HBV genotypes, HBV-DNA level and mutations in the core promoter and pre-core regions of HBV-DNA were examined. The majority of sera contained HBV genotype B (67.8%) and C (27.9%). The median age was matched between genotype B and C (38.2 vs. 42.9 years). The rates of HBeAg seroconversion and G1896A for genotype B were significantly higher than those for genotype C (P<0.05). Genotype C had a higher HBV-DNA level than genotype B. C1858 was frequent, especially in genotype C (62.7%). The most prevalent genotype in ASC and CH was genotype B. The presence of the mutation A1762T/G1764A correlated with disease progression. The triple mutation T1753C/A1762T/ G1764A was quite common and was more prevalent in LC and HCC than in CH and ASC. In Northern Vietnamese, HBV genotypes B and C were prevalent. Genotype C and mutations in the core promoter region were associated with progressive, severe liver diseases.

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“…The important issue of a distinct impact of the various HBV genotypes in HCC has so far not been directly addressed (see review in Orito and Mizokami, 2003;Chan et al, 2004;Pujol and Devesa, 2005). A recent study showed a high prevalence of preS mutant in HCC patients infected with genotypes B and C (Huy et al, 2003).…”

Section: The Role Of Hepatitis B Virus In Liver Cell Carcinogenesismentioning

confidence: 99%

Hepatitis B virus-related hepatocellular carcinoma: paradigms for viral-related human carcinogenesis

et al. 2006

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As discussed in detail in other chapters of this review, chronic hepatitis B (HBV) infection is a major risk factor for hepatocellular carcinoma (HCC). Most HCCs complicate the evolution of an active or inactive cirrhosis. However, some tumors occur on livers with minimal histological changes; the prevalence of such cases varies from one geographical region to the other, being much higher in the southern half of Africa (around 40% of HCCs) than in Asia, America and Europe, where at least 90% of HCCs are associated with the cirrhosis. This heterogeneity is probably a reflection of different environmental and genetic factors. This review will summarize the current knowledge on the mechanisms involved in HBVrelated liver carcinogenesis. It will show in particular how viruses can be viewed as tools to discover and dissect new cellular pathways involved in cancer development and emphasize the potential synergistic effects between HBV and hepatitis C virus, as well as between viral infections and other environmental factors, such as alcohol.

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Genotypic Variability of Hepatitis Viruses Associated With Chronic Infection and the Development of Hepatocellular Carcinoma

Cited by 28 publications

References 154 publications

Calpain activation by hepatitis C virus proteins inhibits the extrinsic apoptotic signaling pathway #

Calpain activation by hepatitis C virus proteins inhibits the extrinsic apoptotic signaling pathway #

Genotype and variations in core promoter and pre-core regions are related to progression of disease in HBV-infected patients from Northern Vietnam

Hepatitis B virus-related hepatocellular carcinoma: paradigms for viral-related human carcinogenesis

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