Enrichment in selected genotypes, basal core and precore mutations of hepatitis B virus in patients with hepatocellular carcinoma in Cameroon

Contemporary and historical human migration patterns shape hepatitis B virus diversity

Infection by hepatitis B virus (HBV) is responsible for approximately 296 million chronic cases of hepatitis B, and roughly 880,000 deaths annually. The global burden of HBV is distributed unevenly, largely owing to the heterogeneous geographic distribution of its subtypes, each of which demonstrates different severity and responsiveness to antiviral therapy. It is therefore crucial to the global public health response to HBV that the spatiotemporal spread of each genotype is well characterized. In this study, we describe a collection of 133 newly sequenced HBV strains from recent African immigrants upon their arrival in Belgium. We incorporate these sequences-all of which we determine to come from genotypes A, D, and E-into a large-scale phylogeographic study with genomes sampled across the globe. We focus on investigating the spatio-temporal processes shaping the evolutionary history of the three genotypes we observe. We incorporate several recently published ancient HBV genomes for genotypes A and D to aid our analysis. We show that different spatio-temporal processes underlie the A, D, and E genotypes with the former two having originated in southeastern Asia, after which they spread across the world. The HBV E genotype is estimated to have originated in Africa, after which it spread to Europe and the Americas. Our results highlight the use of phylogeographic reconstruction as a tool to understand the recent spatiotemporal dynamics of HBV, and highlight the importance of supporting vulnerable populations in accordance with the needs presented by specific HBV genotypes.

Autophagy plays a double-edged sword role in liver diseases

As a highly evolutionarily conserved process, autophagy can be found in all types of eukaryotic cells. Such a constitutive process maintains cellular homeostasis in a wide variety of cell types through the encapsulation of damaged proteins or organelles into double-membrane vesicles. Autophagy not only simply eliminates materials but also serves as a dynamic recycling system that produces new building blocks and energy for cellular renovation and homeostasis. Previous studies have primarily recognized the role of autophagy in the degradation of dysfunctional proteins and unwanted organelles. However, there are findings of autophagy in physiological and pathological processes. In hepatocytes, autophagy is not only essential for homeostatic functions but also implicated in some diseases, such as viral hepatitis, alcoholic hepatitis, and hepatic failure. In the present review, we summarized the molecular mechanisms of autophagy and its role in several liver diseases and put forward several new strategies for the treatment of liver disease.

Hepatitis B virus infection and hepatocellular carcinoma in sub-Saharan Africa: Implications for elimination of viral hepatitis by 2030?

Elimination of viral hepatitis in sub-Saharan Africa by 2030 is an ambitious feat. However, as stated by the World Health Organization, there are unprecedented opportunities to act and make significant contributions to the elimination target. With 60 million people chronically infected with hepatitis B virus (HBV) of whom 38800 are at risk of developing highly fatal hepatocellular carcinoma (HCC) every year, sub-Saharan Africa faces one of the greatest battles towards elimination of viral hepatitis. There is a need to examine progress in controlling the disproportionate burden of HBV-associated HCC in sub-Saharan Africa within the context of this elimination target. By scaling-up coverage of hepatitis B birth dose and early childhood vaccination, we can significantly reduce new cases of HCC by as much as 50% within the next three to five decades. Given the substantial reservoir of chronic HBV carriers however, projections show that HCC incidence and mortality rates in sub-Saharan Africa will double by 2040. This warrants urgent public health attention. The trends in the burden of HCC over the next two decades, will be determined to a large extent by progress in achieving early diagnosis and appropriate linkage to care for high-risk chronic HBV infected persons.

The genetic polymorphism down-regulating HLA-DRB1 enhancer activity facilitates HBV persistence, evolution and hepatocarcinogenesis in the Chinese Han population

Genetic predisposition of human leucocyte antigen (HLA)-DR has been linked to nonresponse to hepatitis B virus (HBV) vaccination. We sought to reveal their effects on chronic infection and evolution of HBV and development of hepatocellular carcinoma (HCC). Genetic polymorphisms at HLA-DR enhancer regions were genotyped in 4588 participants using quantitative PCR. HBV mutations were determined by sequencing. A dual-luciferase assay was applied to detect the enhancer activity. Associations between HLA-DR polymorphisms and postoperative prognosis were investigated in another cohort of 397 HBV-infected HCC patients. Variant alleles (rs3135395-T, rs3135338-C and rs477515-T) were significantly associated with a decreased risk of HBV persistence in Chinese patients. rs3135395-T, rs3135338-C, rs477515-T and rs2395178-G also significantly decreased HCC risk. rs3135395-T, rs477515-T and rs2395178-G were inversely associated with the generation of A1762T/G1764A, T1753V and C1653T, the HCC-risk HBV mutations. Multiplicative interactions of the variant genotypes with the HCC-risk HBV mutations were significantly associated with a decreased risk of HCC. In multivariate Cox analysis, rs477515-T independently predicted a favourable prognosis, with a hazard ratio of 0.48 (P = .002). The activity of the HLA-DRB1 enhancer with rs477515-T was significantly higher than that with rs477515-C. The activity of the HLA-DRB1 enhancer with rs477515-T and that with rs477515-C was significantly up-regulated by interferon-γ and interleukin-4, respectively. Interleukin-6 significantly inhibited the HLA-DRB1 enhancer activity, and this effect was more evident in those carrying rs477515-T. Polymorphisms predisposing to down-regulation of HLA-DR facilitate the Th1-to-Th2 transition and promote HCC development, possibly via selecting the HCC-risk HBV mutations. This can be transformed into specific prophylaxis of HCC.

ACADS acts as a potential methylation biomarker associated with the proliferation and metastasis of hepatocellular carcinomas

BACKGROUND

Hepatocellular carcinomas (HCC) constantly rank among the malignancies with the highest death tolls on the global scale. Moreover, HCC are associated with a limited set of therapeutic options. This is particularly true in the case of advanced stage cancers, where long-term survival is uncommon. For the inoperable, advanced HCC patients, chemotherapy is the main modality of treatment. Due to the lack of known molecular targets, the efficacy of the chemotherapy is limited.

CONCLUSION

These findings clearly indicate that DNA methylation plays a key role in regulating ACADS expression and that it can be a potential therapeutic target for treating HCC.

MATERIALS AND METHODS

A thorough comparative analysis of 282 cancer samples with 47 normal samples from GEO datasets resulted in the observation that that the level of ACADS was significantly downregulated in HCC. Loss-of-function analyses were then conducted to understand the biological function of ACADS in HCC. It was noted that ACADS was involved in the proliferation and metastasis of HCC. Experiments involving the knockdown of DMNT expression led to the discovery that the expression of ACADS in the HCC cells was significantly increased. The TCGA database was then employed to identify tumor tissue samples which showed higher methylation levels at cg01535453, cg08618068, and cg10174836 (which are the target sites of the ACADS CpG islands) as compared with normal liver tissue samples. All these findings indicated that ACADS might be a novel methylation biomarker associated with HCC.