Somatic mutations, viral integration and epigenetic modification in the evolution of hepatitis B virus-induced hepatocellular carcinoma

The role of infections in the causation of cancer in Kenya

Cancer constitutes a major health care burden in the world today with the situation worsening in resource poor settings as seen in most Sub-Saharan African (SSA) countries. Infections constitute by far the most common risk factors for cancer in SSA and being a typical country in this region, Kenya has experienced an upsurge in the incidence of various types of cancers in the last few decades. Although there is limited population-based data in Kenya of infections-associated cancers, this review provides an up-to-date literature-based discussion on infections-associated cancers, their pathogenesis, and preventive approaches in the country. The primary infectious agents identified are largely viral (human immunodeficiency virus, human papillomavirus (HPV), Kaposi's sarcoma-associated herpes virus, Epstein-Barr virus, hepatitis B virus (HBV), hepatitis C virus), and also bacterial: Helicobacter pylori and parasitic: Schistosomiasis haematobium. Cancers associated with infections in Kenya are varied but the predominant ones are Non-Hodgkin lymphoma, Kaposi's sarcoma, Hodgkin lymphoma, Burkitt's lymphoma, cervical, liver, and gastric cancers. The mechanisms of infections-induced carcinogenesis are varied but they mainly seem to stem from disruption of signaling, chronic inflammation, and immunosuppression. Based on our findings, actionable cancer-preventive measures that are economically feasible and aligned with existing infrastructure in Kenya include screening and treatment of infections, implementation of cancer awareness and screening, and vaccination against infections primarily HBV and HPV. The development of vaccines against other infectious agents associated with causation of cancer remains also as an important goal in cancer prevention.

Genetic Landscape of Multistep Hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. Although several targeted therapy agents are available for advanced HCC, their antitumor efficacy remains limited. As the complex genetic landscape of HCC would compromise the antitumor efficacy of targeted therapy, a deeper understanding of the genetic landscape of hepatocarcinogenesis is necessary. Recent comprehensive genetic analyses have revealed the driver genes of HCC, which accumulate during the multistage process of hepatocarcinogenesis, facilitating HCC genetic heterogeneity. In addition, as early genetic changes may represent key therapeutic targets, the genetic landscapes of early HCC and precancerous liver tissues have been characterized in recent years, in parallel with the advancement of next-generation sequencing analysis. In this review article, we first summarize the landscape of the liver cancer genome and its intratumor heterogeneity. We then introduce recent insight on early genetic alterations in hepatocarcinogenesis, especially those in early HCC and noncancerous liver tissues. Finally, we summarize the multistep accumulation of genetic aberrations throughout cancer progression and discuss the future perspective towards the clinical application of this genetic information.

Association between viral infection other than human papillomavirus and risk of esophageal carcinoma: a comprehensive meta-analysis of epidemiological studies

BACKGROUND

Infection with viruses such as human papillomavirus (HPV) is known to induce carcinomas, including esophageal carcinoma (EC). However, the possible role of viruses other than HPV in EC carcinogenesis is unclear in many studies. Here, we aimed to explore the association between infection with viruses other than HPV and EC risk by integrating existing studies of epidemiology in a meta-analysis.

METHODS

The PubMed, Web of Science, Cochrane Library and China National Knowledge Infrastructure databases were searched. The Newcastle-Ottawa scale was used to assess the quality of the included studies. Odds ratios (ORs) or relative risks (RRs) (with 95% confidence intervals [CIs]) were pooled to estimate the association between virus infection and risk of EC.

RESULTS

We included 31 eligible studies involving nine different viruses. Overall, an increased risk of EC was associated with hepatitis B virus (HBV) infection (OR = 1.19, 95%CI 1.01-1.36) and hepatitis C virus (HCV) infection (OR = 1.77, 95%CI 1.17-2.36), but not human immunodeficiency virus (HIV) infection, according to the current evidence. The evidence for an association with Epstein-Barr virus (EBV), herpes simplex virus 1 (HSV-1), JC virus (JCV), cytomegalovirus (CMV), human T-lymphotropic virus 1 (HTLV-1) or Merkel cell polyomavirus (MCPyV) infection was insufficient.

CONCLUSIONS

We confirmed the relationship between HBV and HCV infection and the risk of EC, but we found no association of EC risk with HIV and EBV infection. The roles of HSV-1, JCV, CMV, HTLV-1, and MCPyV were not clear because of the limited number of studies.

Application of human liver organoids as a patient-derived primary model for HBV infection and related hepatocellular carcinoma

The molecular events that drive hepatitis B virus (HBV)-mediated transformation and tumorigenesis have remained largely unclear, due to the absence of a relevant primary model system. Here we propose the use of human liver organoids as a platform for modeling HBV infection and related tumorigenesis. We first describe a primary ex vivo HBV-infection model derived from healthy donor liver organoids after challenge with recombinant virus or HBV-infected patient serum. HBV-infected organoids produced covalently closed circular DNA (cccDNA) and HBV early antigen (HBeAg), expressed intracellular HBV RNA and proteins, and produced infectious HBV. This ex vivo HBV-infected primary differentiated hepatocyte organoid platform was amenable to drug screening for both anti-HBV activity and drug-induced toxicity. We also studied HBV replication in transgenically modified organoids; liver organoids exogenously overexpressing the HBV receptor sodium taurocholate co-transporting polypeptide (NTCP) after lentiviral transduction were not more susceptible to HBV, suggesting the necessity for additional host factors for efficient infection. We also generated transgenic organoids harboring integrated HBV, representing a long-term culture system also suitable for viral production and the study of HBV transcription. Finally, we generated HBV-infected patient-derived liver organoids from non-tumor cirrhotic tissue of explants from liver transplant patients. Interestingly, transcriptomic analysis of patient-derived liver organoids indicated the presence of an aberrant early cancer gene signature, which clustered with the hepatocellular carcinoma (HCC) cohort on The Cancer Genome Atlas Liver Hepatocellular Carcinoma dataset and away from healthy liver tissue, and may provide invaluable novel biomarkers for the development of HCC and surveillance in HBV-infected patients.

Studies on the correlation between mutation and integration of HBV in hepatocellular carcinoma

It is well known that both the mutation and integration of the Hepatitis B virus (HBV) are of great significance in liver cancer, however, the relationship between mutation and integration is still unclear. In the present study, sequencing data from 426 previously published samples were analyzed and 5374 specific HBV mutations in cancer tissues were discovered. By comparing integrated samples and non-integrated samples, we found that the integrated samples had higher sample single nucleotide variants (SNVs) positive rates and SNV numbers, as well as higher sample frequency of SNV in the X region of the HBV genome. Samples with HBV integration in the telomerase reverse transcriptase (TERT) region showed higher SNV positive rates and numbers than samples without integration. Moreover, the SNVs (209 [T>G] and 531 [T>C; T>G]) were seen with higher frequency in samples with integration in the TERT region. Our study showed that the occurrence of viral integration events is closely related to the occurrence of SNV, and SNV in the X region should be more directly associated with viral integration. The present study provides an initial exploration of the relationship between HBV mutation and integration to help improve our understanding of the relationship between viral integration and mutation.

3D human liver organoids: An in vitro platform to investigate HBV infection, replication and liver tumorigenesis

Hepatitis B Virus (HBV) infection is a leading cause of chronic liver cirrhosis and hepatocellular carcinoma (HCC) with an estimated 400 million people infected worldwide. The precise molecular mechanisms underlying HBV replication and tumorigenesis have remained largely uncharacterized due to the lack of a primary cell model to study HBV, a virus that exhibits stringent host species and cell-type specificity. Organoid technology has recently emerged as a powerful tool to investigate human diseases in a primary 3D cell-culture system that maintains the organisation and functionality of the tissue of origin. In this review, we describe the utilisation of human liver organoid platforms to study HBV. We first present the different categories of liver organoids and their demonstrated ability to support the complete HBV replication cycle. We then discuss the potential applications of liver organoids in investigating HBV infection and replication, related tumorigenesis and novel HBV-directed therapies. Liver organoids can be genetically modified, patient-derived, expanded and biobanked, thereby serving as a clinically-relevant, human, primary cell-derived platform to investigate HBV. Finally, we provide insights into the future applications of this powerful technology in the context of HBV-infection and HCC.

Characterization of hepatitis B virus DNA integration patterns in intrahepatic cholangiocarcinoma

AIM

Hepatitis B virus (HBV) integration is one of the mechanisms contributing to hepatocellular carcinoma (HCC) development. However, the status of HBV integration in intrahepatic cholangiocarcinoma (ICC) is poorly understood. This study aims to characterize the viral integration in HBV-related ICC.

METHODS

The presence of HBV S and C gene in ICCs and the paratumor tissue was determined by polymerase chain reaction direct sequencing. Hepatitis B virus integration was detected by a high-throughput capture sequencing method. The expression analysis of the genes targeted by HBV in ICC was undertaken in The Cancer Genome Atlas dataset.

RESULTS

Hepatitis B virus S and/or C gene fragments were detected in 71.43% (10/14) ICCs and 57.14% (8/14) paratumor tissues. Using the high-throughput capture sequencing approach, 139 and 183 HBV integration breakpoints were identified from seven ICC and seven paired paratumor tissues, respectively. Seven genes (TERT, CEACAM20, SPATA18, TRERF1, ZNF23, LINC01449, and LINC00486) were recurrently targeted by HBV-DNA in different ICC tissues or different cell populations of the same tissue. TERT, which is the most preferential HBV target gene in HCC, was found to be repeatedly interrupted by HBV-DNA in three different ICC tissues. Based on The Cancer Genome Atlas dataset, TERT, as well as three other HBV recurrently targeted genes (SPATA18, TRERF1, and ZNF23), showed differential expression levels between ICC and para-ICC tissues.

CONCLUSIONS

Taken together, HBV integration is a common event in HBV-related ICC. The HBV recurrent integration genes identified from this study, such as TERT, provide new clues for further research on the causative link between HBV infection and ICC.

Regulation of Long Non-Coding RNA-Dreh Involved in Proliferation and Migration of Hepatic Progenitor Cells during Liver Regeneration in Rats

Liver regeneration plays a significant role in protecting liver function after liver injury or chronic liver disease. Long non-coding RNAs (lncRNAs) are considered to be involved in the proliferation of hepatocytes and liver regeneration. Therefore, this study aimed to explore the effects of LncRNA-Dreh on the regulation of hepatic progenitor cells (HPCs) during liver regeneration in rats. Initially, the rat model of liver injury was established to investigate the effect of LncRNA-Dreh down-regulation on liver tissues of rats with liver injury. Subsequently, HPCs line WB-F344 cells were transfected with interference plasmid of LncRNA-Dreh and the expression of LncRNA-Dreh and Vimentin was detected. The proliferation and migration ability of WB-F344 cells, as well as the content of albumin (ALB) and alpha fetoprotein (AFP) in cell differentiation were then determined. Disorderly arranged structure of liver tissue, a large number of HPCs set portal area as center extended to hepatic lobule and ductular reaction were observed in liver tissues of rats with liver injury. The expression of LncRNA-Dreh decreased while Vimentin increased in liver tissues of rats with liver injury. Moreover, the proliferation and migration ability, expression of Vimentin and AFP in WB-F344 cells were increased after silencing of LncRNA-Dreh and ALB was decreased. Collectively, our findings demonstrate that inhibition of LncRNA-Dreh can enhance the proliferation and migration abilities of HPCs in liver regeneration but cause abnormal differentiation of HPCs.

A Potential Prognostic Gene Signature for Predicting Survival for Glioblastoma Patients

OBJECTIVE

This study aimed to screen prognostic gene signature of glioblastoma (GBM) to construct prognostic model.

METHODS

Based on the GBM information in the Cancer Genome Atlas (TCGA, training set), prognostic genes (Set X) were screened by Cox regression. Then, the optimized prognostic gene signature (Set Y) was further screened by the Cox-Proportional Hazards (Cox-PH). Next, two prognostic models were constructed: model A was based on the Set Y; model B was based on part of the Set X. The samples were divided into low- and high-risk groups according to the median prognosis index (PI). GBM datasets in Gene Expression Ominous (GEO, GSE13041) and Chinese Glioma Genome Atlas (CGGA) were used as the testing datasets to confirm the prognostic models constructed based on TCGA.

RESULTS

We identified that the prognostic 14-gene signature was significantly associated with the overall survival (OS) in the TCGA. In model A, patients in high- and low-risk groups showed the significantly different OS (P = 7.47 × 10-9, area under curve (AUC) 0.995) and the prognostic ability were also confirmed in testing sets (P=0.0098 and 0.037). The model B in training set was significant but failed in testing sets.

CONCLUSION

The prognostic model which was constructed based on the prognostic 14-gene signature presented a high predictive ability for GBM. The 14-gene signature may have clinical implications in the subclassification of GBM.

Correlation between CT features and liver function and p53 expression in hepatitis, cirrhosis and hepatocellular carcinoma

This study aimed to investigate the correlation between CT features and liver function and p53 expression in hepatitis, cirrhosis and hepatocellular carcinoma (HCC). Forty patients with HCC, 30 patients with cirrhosis and 30 patients with chronic hepatitis were enrolled between December, 2015 and December, 2016. At the same time, normal liver tissues collected from 30 patients with hepatic hemangioma were used as the normal control group. All the patients were scanned by CT. Average body surface area, left outer lobe and caudate lobe volume, and the proportions of left outer lobe and caudate lobe to the whole liver were calculated. Biochemical indexes of liver function were determined. The pathological tissues of all the subjects were analyzed. Compared with the control group, total liver volume of the HCC group was significantly reduced (P<0.05). Compared with the HCC group, the volume of the left outer lobe increased in the hepatitis group and the cirrhosis group. Compared with control group, caudate lobe volume increased significantly in the hepatitis group (P<0.05). Compared with the control group, the volume of the left outer lobe and the proportion of caudate lobe to the whole liver volume was significantly increased in all three groups (P<0.05). Liver function-related indicators in the HCC and cirrhosis groups were significantly different from those in the control group (P<0.05). The expression level of p53 in HCC was significantly higher than that in the control group (P<0.05). The accuracy of diagnosis by using both p53 and CT was higher than the use of p53 or CT alone. CT can accurately measure the volume of each lobe of the liver, and p53 has important clinical values in the diagnosis of liver diseases. Thus, the reasonable combination of the two can effectively improve the diagnostic accuracy.

Linking common non-coding RNAs of human lung cancer and M. tuberculosis

Lung cancer and pulmonary tuberculosis caused by Mycobacterium are two major causes of deaths worldwide. Tuberculosis linked lung cancer is known. However, the precise molecular mechanism of Mycobacterium associated increased risk of lung cancer is not understood. We report 45 common human miRNAs deregulated in both pulmonary tuberculosis and lung cancer. We show that sRNA_1096 and sRNA_1414 from M. tuberculosis have sequence homology with human mir-21. Hence, the potential role of these three small non-coding RNAs in rifampicin resistance in pulmonary tuberculosis is implied. Further, the linking of sRNA_1096 and sRNA_1414 from M. tuberculosis with the host lung tumorigenesis is inferred. Nonetheless, further analysis and validation is required to associate these three non-coding RNAs with Mycobacterium associated increased risk of lung cancer.

Concomitant use of heat-shock protein 70, glutamine synthetase and glypican-3 is useful in diagnosis of HBV-related hepatocellular carcinoma with higher specificity and sensitivity

Hepatocellular carcinoma is the third leading cause of cancer-related death worldwide and late diagnosis is the main cause of death in HCC patients. In this study expression patterns of HSP70, GPC3 and GS and their relationships with pathogenesis of HCC in Iranian patients were investigated. The expression of HSP70, GPC3 and GS were determined by immunohistochemistry and quantitative real-time PCR (q-PCR) methods, using 121 cases from patients with HBV alone, HCC without HBV, HBV+HCC and 30 normal tissues as control group. HSP70, GPC3 and GS were expressed in higher levels in HBV-related HCC samples compared to HBV alone group. The results showed that the labeling index of HSP70, GPC3 and GS are correlated with immunohistochemical and molecular expressions of HSP70, GPC3 and GS. The sensitivity and specificity for HCC diagnosis were 43.4% and 89.7% for HSP70, 64.3% and 90.4% for GPC3, and 60.7% and 94.3% for GS, respectively. The sensitivity and specificity of the panels with 3, 2 and 1 positive markers, regardless of which one, were 21.6% and 100%, 51.3% and 100% and 93.4% and 80.5% respectively. The current study demonstrated an association between HSP70, GPC3 and GS expressions and HBV-related HCC in our population. It was concluded that HSP70, GPC3 and GS expressions could be useful biomarkers for increasing the specificity and sensitivity of HCC diagnosis to acceptable level. Also, proper combinations of these 3 markers could improve diagnostic accuracy.

MicroRNAs as possible biomarkers for diagnosis and prognosis of hepatitis B- and C-related-hepatocellular-carcinoma

Aim of the present review is to summarize the current knowledge about the potential relationship between miRNAs and hepatitis B virus (HBV)-hepatitis C virus (HCV) related liver diseases. A systematic computer-based search of published articles, according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis Statement, was performed to identify relevant studies on usefulness of serum/plasma/urine miRNAs, as noninvasive biomarkers for early detection of HBV and HCV-induced hepatocellular carcinoma (HCC) development, as well as for its prognostic evaluation. The used Medical Subject Headings terms and keywords were: “HBV”, “HCV”, “hepatocellular carcinoma”, “microRNAs”, “miRNAs”, “diagnosis”, “prognosis”, “therapy”, “treatment”. Some serum/plasma miRNAs, including miR-21, miR-122, mi-125a/b, miR-199a/b, miR-221, miR-222, miR-223, miR-224 might serve as biomarkers for early diagnosis/prognosis of HCC, but, to date, not definitive results or well-defined panels of miRNAs have been obtained. More well-designed studies, focusing on populations of different geographical areas and involving larger series of patients, should be carried out to improve our knowledge on the potential role of miRNAs for HCC early detection and prognosis.

Adaptive methylation regulation of p53 pathway in sympatric speciation of blind mole rats, Spalax

Epigenetic modifications play significant roles in adaptive evolution. The tumor suppressor p53, well known for controlling cell fate and maintaining genomic stability, is much less known as a master gene in environmental adaptation involving methylation modifications. The blind subterranean mole rat Spalax eherenbergi superspecies in Israel consists of four species that speciated peripatrically. Remarkably, the northern Galilee species Spalax galili (2n = 52) underwent adaptive ecological sympatric speciation, caused by the sharply divergent chalk and basalt ecologies. This was demonstrated by mitochondrial and nuclear genomic evidence. Here we show that the expression patterns of the p53 regulatory pathway diversified between the abutting sympatric populations of S. galili in sharply divergent chalk-basalt ecologies. We identified higher methylation on several sites of the p53 promoter in the population living in chalk soil (chalk population). Site mutagenesis showed that methylation on these sites linked to the transcriptional repression of p53 involving Cut-Like Homeobox 1 (Cux1), paired box 4 (Pax 4), Pax 6, and activator protein 1 (AP-1). Diverse expression levels of p53 between the incipiently sympatrically speciating chalk-basalt abutting populations of S. galili selectively affected cell-cycle arrest but not apoptosis. We hypothesize that methylation modification of p53 has adaptively shifted in supervising its target genes during sympatric speciation of S. galili to cope with the contrasting environmental stresses of the abutting divergent chalk-basalt ecologies.

Relation between sex hormones and hepatocellular carcinoma

Males have higher incidence of hepatocellular carcinoma (HCC) than females. Sex hormones may be a risk factor. The aim was to determine the levels of sex hormones in male and female patients with HCC and cirrhosis versus controls and its possible relationship with HCC. This study was conducted on 90 subjects divided into 40 patients with HCC, 30 patients with liver cirrhosis and 20 apparently healthy subjects complete blood picture, liver function tests. Determination of AFP levels and hormonal assay of oestrogen, progesterone, total testosterone, prolactin, FSH and LH were performed on all subjects. Total testosterone levels were significantly decreased in the two patients groups compared with controls. While oestrogen levels were significantly decreased in the HCC group in comparison with other two groups, prolactin levels were significantly decreased in the HCC group compared with the liver cirrhosis group and increased in the liver cirrhosis group when compared to controls. FSH and LH levels were significantly increased in the HCC group when compared to controls. There is no significant correlation between sex hormones assay and both the size of HCC and degree of cirrhosis in both patient groups. It is concluded that there is no strong relation between sex hormones and HCC when the study was carried out on the levels of sex hormones in patients with HCC.

Studied microRNA gene expression in human hepatocellular carcinoma by microRNA microarray techniques

AIM: To achieve a better understanding of the molecular mechanisms of microRNA expression changes involved in hepatocellular carcinoma.

METHODS: In this research process, patients were not treated with antivirals, immunosuppressants or immunomodulators for at least 6 mo before collecting serum. The study population was composed of 35 outpatient hepatitis B virus (HBV) cases and 12 healthy control cases from the Affiliated Hospital of Inner Mongolia Medical University (Inner Mongolia, China) from July 2013 to April 2014. The 35 HBV cases were divided into two groups: a hepatocirrhosis group with 20 cases and a liver cancer group with 15 cases. All 35 cases carried HBsAg. The diagnostic criteria followed the European Association for the Study of the Liver 2012 (EASL2012) standards. MicroRNA (miRNA) was extracted from a control group of patients, a group with hepatocirrhosis and a group with liver cancer and its quality was analyzed using the human V2 microRNA expression beadchip. Cluster analysis and a radar chart were then applied to the miRNA changes.

RESULTS: The miRNA-qualified rate of human serum samples was 93%. The concentration of a single sample was > 200 ng/μL and the volume was > 5 μL. All miRNA serum samples were uncontaminated by the genome. The Mann-Whitney test showed significant differences in miRNA between each group, with a detection P-value of < 0.05. Illumina software was set up with Diff Score set to ± 13, meaning that P = 0.001.There were significant changes in miRNA expression between the three groups. miRNA-183 was the most up-regulated, followed by miRNA-373. miRNA-129 and miRNA-188 were both strongly down-regulated and miRNA-378 was down-regulated a small amount. The liver cancer group had greater changes, which indicated that changes in miRNA expression levels were caused by hepatocirrhosis. The liver cancer disease course then further increased these changes. In the pentagon created by these five miRNAs, three groups showed significant deviation. The liver cancer group had a bigger deviation trend. The chart indicated that miRNA expression changes occurred in the hepatocirrhosis group, which increased in the liver cancer disease course and were irreversible.

CONCLUSION: There was a significant relationship between the irreversible up-regulation of miRNA-183/373 and down-regulation of miRNA-129/188/378 and incidences of hepatocirrhosis and liver cancer.

Expression of P53 and HSP70 in Chronic Hepatitis, Liver Cirrhosis, and Early and Advanced Hepatocellular Carcinoma Tissues and Their Diagnostic Value in Hepatocellular Carcinoma: An Immunohistochemical Study

Background

Tumor protein (P53) and heat shock protein 70 (HSP70) play key roles in chronic liver diseases. This study aimed to characterize P53 and HSP70 expression in chronic hepatitis (CH), liver cirrhosis (LC), early and advanced HCC, and to analyze their diagnostic value in hepatocellular carcinoma (HCC).

Material/Methods

Immunohistochemical staining was conducted to evaluate the expression of P53 and HSP70 in 200 human liver tissue specimens, with advanced HCC (n=80), early HCC (n=30), CH (n=30), LC (n=30), and Controls (n=30).

Results

P53 expression levels were lower in LC than those of HCC, but remained on par with those of CH and Controls. HSP70 expression levels were higher in HCC than those of LC, CH, and Controls. The sensitivity and specificity for HCC diagnosis were: 50.9% and 98.9% for P53, and 78.2 and 77.8% for HSP70, respectively. The sensitivity and specificity of different combinations were: 95.5% and 85.5% with either P53 or HSP70 being positive, and 33.6% and 98.9% if both were positive. Among the differentiation stages marked low, intermediate, and high in HCC, the P53 positive rate was higher in the low than in the intermediate, which was higher than that in the high. HSP70 positive rate was higher in the low and the intermediate than in the high, but no obvious changes were found between the low and the intermediate.

Conclusions

P53 and HSP70 could be potential biomarkers for HCC diagnosis, and proper combinations of these 2 markers could improve diagnostic accuracy.