Hepatitis B Virus Pregenomic RNA in Hepatocellular Carcinoma: A Nosological and Prognostic Determinant.

Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC). However, very little is known about the replication of HBV in HCC tissues. We analyzed viral and cellular parameters in HCC (T) and nontumor liver (NT) samples from 99 hepatitis B surface antigen (HBsAg)-positive, virologically suppressed patients treated by tumor resection or liver transplantation. We examined total HBV DNA and RNA as well as covalently closed circular DNA (cccDNA) and pregenomic RNA (pgRNA), which are considered as markers of active HBV replication. Total HBV DNA and RNA were detected in both T and NT samples in a majority of cases, but only a subset of tumors harbored detectable levels of HBV cccDNA and pgRNA (39% and 67%) compared to NT livers (66% and 90%; P < 0.01). Further evidence for HBV replication in tumor tissues was provided by sequencing of the X gene derived from episomal forms, showing that HBV genotypes differed between T and matched NT samples in 11 cases. The detection of pgRNA and cccDNA in tumors was correlated to the absence of tumorous microvascular invasion and to better patient survival. Analysis of gene expression profiles by Agilent microarrays revealed that pgRNA-positive HCCs were characterized by low levels of cell cycle and DNA repair markers and expression of the HBV receptor, sodium taurocholate cotransporting polypeptide, indicating well-differentiated tumors. CONCLUSION: HCC replicating HBV represents a subtype of weakly invasive HCC with a transcriptomic signature. pgRNA originating from nonintegrated, complete HBV genomes is a sensitive marker for viral replication and prognosis. (Hepatology 2018;67:86-96).

Risk factors for hepatocellular carcinoma in Caucasian patients with non-viral cirrhosis: the importance of prior obesity.

BACKGROUND & AIMS: In patients with cirrhosis, the risk of hepatocellular carcinoma (HCC) depends upon age, gender and the etiology of liver disease. Few studies are available in Caucasian patients with alcoholic or metabolic cirrhosis without viral hepatitis. METHODS: Cross-sectional clinical data from 905 HCV- and HBV-negative Caucasian patients with alcoholic or metabolic cirrhosis were prospectively collected in four French centres. The risk factors for HCC were identified by logistic regression analysis in the whole population and in a nested case-control study. RESULTS: The etiology of cirrhosis was alcoholic (48%), metabolic (7%) or mixed (45%). Patients were predominantly male (80%), mean age 62 years old and 31% had HCC. Mean body mass index (BMI) was 27 ± 5 and 30% were obese at inclusion. The maximum BMI reached throughout life was 31 ± 6 and 63% had been obese. Ninety percent of the population had daily alcohol consumption, 73% were smokers. Hepatocellular carcinoma was independently related to male gender (P < 0.0001), older age (P < 0.0001), past obesity (P = 0.007), diabetes (P = 0.037), abnormal levels of transaminases (P < 0.0001) and tobacco consumption (P = 0.007). The case-control study (200 HCC cases matched with 400 non-HCC cases for gender, age and Child-Pugh score) confirmed past obesity, tobacco and abnormal levels of transaminases. CONCLUSIONS: Beside diabetes, male gender and age, a past history of obesity, but not an existing overweight, as well as exposure to tobacco and elevated transaminases were three risk factors which could improve the strategy for HCC screening in Caucasian cirrhotic patients without hepatitis B or C.

Recombination of hepatitis B virus DNA in patients with HIV.

INTRODUCTION: Hepatitis B is a major cause of death in patients with HIV who usually receive drugs active against hepatitis B virus (HBV). The variability of HBV DNA over time has been little studied. Recombination between different HBV genotypes has been described in many cross-sectional studies, but the frequency of intergenotypic and intragenotypic recombinations in individual patients is unknown. METHODS: 32 HIV-positive and 11 HIV-negative patients who remained HBV viraemic despite antiviral therapy for at least 1 year were studied. Genotyping was based on line probe assays and genotype-specific PCR. The variability of HBV DNA over time was examined with restriction length and single-strand conformational polymorphism (RFLP-SSCP). HBV DNA sequences obtained by cloning a 2800 bp PCR fragment were analysed for phylogenetic parameters (diversity and selection pressure) and recombination was detected with RDP3 software. RESULTS: Large fragments of HBV DNA could be amplified at two different time points in 33 patients. Marked quasi-species modifications occurred in 14 patients. In seven of these patients and in one patient with no change detectable by RFLP-SSCP, the 2800 bp fragment was cloned at two time points at least. In four (57%) of these seven patients, various intergenotypic or intragenotypic recombination events were detected between subvariants present in the initial quasi-species. Recombinant fragments mostly harboured antiviral resistance determinants and reflected a large increase in diversity and in positive selection pressure on the entire HBV quasi-species. CONCLUSIONS: In coinfected patients, HBV DNA recombination events are frequent during antiviral therapy, corresponding to increased positive selection pressure on the HBV quasi-species and to conservation of antiviral resistance mutations. In this population and at the individual level, recombination is a significant source of HBV genetic variability.

Hepatocellular carcinoma is associated with an increased risk of hepatitis B virus recurrence after liver transplantation.

BACKGROUND & AIMS: Hepatitis B virus (HBV) recurrence after orthotopic liver transplantation (OLT) is significantly reduced by prophylaxis with hyperimmune antibody to hepatitis B surface antigen (anti-HBs) globulins (HBIG) and antiviral drugs. The role of hepatocellular carcinoma (HCC) in HBV recurrence remains unclear. We investigated the association between HCC pre-OLT and HBV recurrence post-OLT. METHODS: We studied 99 hepatitis B surface antigen-positive patients who underwent OLT for cirrhosis. The median follow-up period was 43 months. All patients received HBIG, and 51 also received lamivudine and/or adefovir. Of these 99 patients, 31 had HCC before OLT. Total HBV DNA and covalently closed circular (ccc)-DNA were measured in tumor and nontumor tissues from the explanted livers of 16 of these 31 HCC patients and, also, in a context of tumor recurrence, in 3 patients who developed HBV/HCC recurrence. RESULTS: Fourteen patients (14.1%) developed HBV recurrence within a median period of 15 months post-OLT. HCC at OLT, a pre-OLT HBV DNA viral load > or = 100,000 copies/mL, and HBIG monoprophylaxis were independently associated with HBV recurrence post-OLT. Eleven out of the 31 patients with HCC at OLT presented with HBV recurrence and 3 out of the 68 patients without HCC had HBV recurrence (P < .0001). HBV recurrence was more frequent in patients who developed HCC recurrence (7/8 patients, 87.5%) than in those who did not (4/23 patients, 17.4%) (P < .0001). In the 16 explanted livers, cccDNA was detectable in HCC cells in 11 and in nontumor cells in 12. cccDNA was detected in a context of HCC recurrence in 2 of the 3 patients tested who developed HBV/HCC recurrence. CONCLUSIONS: The associations of HCC pre-OLT, and HCC recurrence with HBV recurrence post-OLT, and the detection of HBV DNA and cccDNA in HCC suggest that HBV replication in tumor cells may contribute to HBV recurrence post-OLT.

Hepatitis B virus replicating in hepatocellular carcinoma encodes HBx variants with preserved ability to antagonize restriction by Smc5/6.

Hepatitis B virus infection is a major cause of liver diseases including hepatocellular carcinoma (HCC). The viral regulatory protein HBx is essential for viral replication and has been involved in the development of HCC. Recently, we characterized a subset of HCCs that replicate HBV. Our aim was to characterize HBx encoded by the full-length HBV DNA (cccDNA) in HCC and non-HCC liver. HBx genes were amplified and sequenced from eight paired HCC and non-HCC tissues in which HBV cccDNA and pgRNA were both present. Sequence analyses identified twelve amino acid positions mutated between HCC and non-HCC liver, and detected in at least three cases. We next assessed the impact of these mutations on HBx function by testing their transcriptional activity. We examined their ability to rescue the transcription of HBV virus deficient for HBx in differentiated HepaRG cells and to induce Smc5/6 degradation, which is mandatory for viral replication. We assessed their capacity to activate a CREB-dependent reporter. Finally we analyzed their growth suppressive activity using colony formation assays. Our results showed that most HBx variants isolated from HCC retain their ability to support HBV cccDNA transcription and to degrade Smc5/6. Strikingly, HCC specific HBx variants are impaired in their antiproliferative activity, which may be detrimental for tumor growth. In conclusion, in contrast to previous observations that tumor HBx variants lack transcriptional activity, we showed here that HBx variants have retained their ability to counteract Smc5/6 and thus to activate cccDNA transcription although they tend to lose antiproliferative activity.

The cAMP-responsive unit of the human insulin-like growth factor-binding protein-1 coinstitutes a functional insulin-response element.

Insulin-like growth factor-binding protein-1 (IGFBP-1) is one of the genes involved in glucose homeostasis. In vivo, its level is increased by counter-regulatory hormones (glucocorticoids and glucagon via its second messenger cAMP) and decreased by insulin, these variations being primarily correlated with IGFBP-1 gene transcription. Previous reports described a functional insulin response element (IRE), immediately 5'- to the glucocorticoid response element (GRE). This IRE has been shown to mediate partial inhibition (1) of basal IGFBP-1 promoter activity and (2) of glucocorticoid-induced stimulation of gene transcription by insulin. In this work, using human HepG2 hepatoma cells as a model system, we showed: (1) that insulin inhibited both basal and cAMP-induced hIGFBP-1 promoter (nt-1 to -341) activity; (2) that in the absence of insulin, forkhead box class O (FOXO) transcription factors enhance constitutive hIGFBP-1 promoter activity without interfering with the stimulatory effect of cAMP; (3) that PI-3' kinase signaling is involved in the inhibition of constitutive and cAMP-induced promoter activities by insulin; (4) that wild-type FOXO-1 mediates the inhibitory effect of insulin on the promoter, although FOXO-1(Ala3), a nonphosphorylatable mutant of FOXO-1, does not; (5) that the cAMP-responsive unit (CRU), that includes a putative IRE (nt-265 to -282) and a cAMP responsive element (CRE; nt-258 to -263), is sufficient per se to mediate both cAMP stimulation of a heterologous promoter, and inhibition of both basal and cAMP-induced promoter activities by insulin; and (6) that the inhibitory effects of insulin on the isolated CRU are mediated by the FOXOs. This study is the first evidence for the occurrence of a second IRE within hIGFBP-1 promoter sequences, IRE(CRU), located 5'- to the CRE.

Pleiotropic effects of PI-3' kinase/Akt signaling in human hepatoma cell proliferation and drug-induced apoptosis.

IGF-II and type I-IGF receptor (IGF-IR) gene expression is increased in primary liver tumors, and transgenic mice overexpressing IGF-II in the liver develop hepatocellular carcinoma (HCC) spontaneously, suggesting that alterations of IGF-IR signaling in vivo may play a role in the auto/paracrine control of hepatocarcinogenesis. We have addressed the contribution of PI-3'K/Akt signaling on the proliferation of HepG2 human hepatoma cells and on their protection against doxorubicin-induced apoptosis. Both basal HepG2 cell DNA replication and that stimulated by IGF-IR signaling were inhibited by the specific PI-3'K inhibitor Ly294002 (Ly). In the former case, PI-3'K signaling overcame cell cycle arrest in G1 via increased cyclin D1 protein and decreased p27kip1 gene expression. Doxorubicin treatment induced apoptosis in HepG2 cells and was concomitant with the proteolytic cleavage of Akt-1 and -2. Drug-induced apoptosis was reversed by IGF-I and this effect was (i) dependent on Akt-1 and -2 phosphorylation and (ii) accompanied by the inhibition of initiator caspase-9 activity, suggesting that IGF-IR signaling interferes with mitochondria-dependent apoptosis. Accordingly, Ly enhanced doxorubicin-induced apoptosis and suppressed its reversal by IGF-I. Altogether, the data emphasize the crucial role of PI-3'K/Akt signaling (i) in basal as well as IGF-IR-stimulated HepG2 cell proliferation and (ii) in controlling both doxorubicin-induced apoptosis (e.g., drug-induced cleavage of Akt) and its reversal by IGF-I (protection against apoptosis parallels the extent of Akt phosphorylation). They suggest that targeting Akt activity or downstream Akt effectors (e.g., GSK3-beta, FOXO transcription factors) may help define novel therapeutic strategies of increased efficacy in the treatment of HCC-bearing patients.

An evaluation of the role of insulin-like growth factors (IGF) and of type-I IGF receptor signalling in hepatocarcinogenesis and in the resistance of hepatocarcinoma cells against drug-induced apoptosis.

Strong evidence emphasizes the role of the insulin-like growth factor (IGF) system and of type-I IGF receptor (IGF-IR) signalling in tumourigenesis. In this connection: (i) changes in the expression pattern of components of the IGF system (autocrine/paracrine expression of IGF-I and -II, overexpression of IGF-IR, decreased expression of IGF-binding proteins (IGFBPs) and of type-II IGF receptor/cation-independent mannose-6-phosphate receptor (IGF-II/M6PR) and (ii) increased serum concentrations of proteases that cleave the IGFBPs (e.g., cathepsin D) were observed in patients with hepatocellular carcinomas (HCC), in human hepatoma cell lines and in their conditioned culture medium, as well as in rodent models of hepatocarcinogenesis. Accordingly, studies carried out with animal models do suggest that the IGF system and IGF-IR signalling may play a role in hepatocarcinogenesis and in deregulated proliferation and apoptosis of HCC cells. Finally the instrumental role of Raf/MEK/ERK, one of the signalling cascades stimulated by IGF-IR, in anthracycline-induced apoptosis of HepG2 and Huh-7 human hepatoma cell lines emphasizes that care must be taken when designing combinations of antitumoural molecules for antineoplastic treatment. This review addresses the putative roles of the IGF system in primary HCC, with a special focus on the underlying molecular mechanisms. In a second part it emphasizes the putative interference of IGF-IR signalling with chemotherapeutic drug-induced apoptosis in human hepatoma cells.

Diverse roles of hepatitis B virus in liver cancer.

Hepatitis B virus (HBV) is a widespread human pathogen responsible for acute and chronic liver diseases. The hepatitis B burden is particularly heavy in endemic countries, where liver cirrhosis and hepatocellular carcinoma are leading causes of death. However, the oncogenic role of HBV remains enigmatic. As the virus has no cytopathic effect, liver damage is attributed to immune responses that induce inflammation, apoptosis and regeneration, fostering the accumulation of genetic and epigenetic alterations. In a more direct action, frequent integration of HBV DNA into host chromosomes may lead to insertional mutagenesis of cancer-related genes and chromosomal instability. HBV proteins, notably the HBx transactivator, participate as co-factors in oncogenesis. Better understanding of hepatitis B pathogenesis is mandatory for improving disease management.

Clinical and therapeutic implications of hepatitis C virus compartmentalization.

BACKGROUND & AIMS: Blood mononuclear cells (BMCs) frequently are infected by hepatitis C virus (HCV) variants that are not found in plasma. The influence of this compartmentalization on the natural and therapeutic outcome of hepatitis C is unknown. METHODS: We studied 119 patients with previously untreated chronic HCV infection. Sixty-five of these patients started first-line treatment with pegylated interferon-alfa and ribavirin after enrollment in the study. The internal ribosomal entry site (IRES) of HCV RNA was amplified and compared between plasma and BMCs by means of single-strand conformational polymorphism (SSCP) analysis, line-probe assay, and cloning sequencing. RESULTS: The IRES SSCP patterns differed between plasma and BMCs in 54 (48%) of 113 assessable patients. Twenty-seven (24%) of these patients were co-infected by 2 HCV types or subtypes, only 1 of which was detectable in BMCs (n = 25) or in plasma (n = 2). SSCP-defined compartmentalization was more frequent in former drug users than in others (35/56 [60%] vs 19/56 [34%]; P < .01), and less frequent in patients with genotype 1 HCV in plasma (26/73 [24%] vs 28/40 [65%]; P < .01). The only variables that were independently predictive of a sustained virologic response were SSCP-defined compartmentalization (25/31 vs 10/32; P = .0001) and genotype 2 or 3 infection of BMCs (22/31 vs 8/34; P = .002). CONCLUSIONS: A significant proportion of patients with hepatitis C are co-infected by 2 or more HCV variants with distinct IRES sequences and distinct cellular tropism. This compartmentalization is a strong independent predictor of treatment efficacy.