First recorded presence of anthropogenic fly-ash particles in coral skeletons.

Fly-ash particles formed during industrial fossil-fuel combustion show a globally observed rapid increase in concentration within natural archives post-1950 and have been proposed as a marker for the Anthropocene Epoch. Here, we present the first record of fly-ash particles incorporated into coral skeletons. Particles are present in Mediterranean corals between CE 1957 and 1992 at concentrations of 8-30 g-1 coral, mirroring the period of increased industrial activity in the area, and corroborating with spheroidal carbonaceous particle (SCP) records globally. The findings have important implications for the use of SCPs as markers in natural archives. With the exception of microplastics, this is the first evidence of particulate contamination in corals collected from natural environments. Further research is needed to understand incorporation pathways into coral skeletons, any subsequent ecotoxicological impact of contaminants, and the influence on overall coral health globally.

Hepatocellular carcinoma: Epidemiology, pathogenesis and surveillance - implications for sub-Saharan Africa.

Hepatocellular carcinoma (HCC) originates from hepatocytes usually secondary to chronic inflammation and cirrhosis. It is an important disease of global significance with a high incidence and mortality. It is the fifth and eighth most common cancer in males and females, respectively. HCC is also extremely lethal; in 2015 it was the second and sixth most common cause of death from cancer in males and females, respectively. Chronic viral hepatitis B and C are the most frequent risk factors for the development of HCC, and the global distribution of HCC largely mirrors that of chronic viral hepatitis. More recently, there has been a notable increase in the incidence of HCC as a result of obesity-related fatty liver disease. Here, we review the epidemiology of HCC, examine recent advances in our understanding of the pathogenesis of HCC, discuss the implications for identification of potential therapeutic targets, and provide the most updated recommendations on surveillance for HCC, with particular attention to the unique challenges and potential opportunities to reduce the burden of illness and death from HCC in sub-Saharan Africa.

Anti-viral therapy is associated with improved survival but is underutilised in patients with hepatitis B virus-related hepatocellular carcinoma: real-world east and west experience.

BACKGROUND: Hepatitis B virus (HBV) is the leading cause of hepatocellular carcinoma (HCC) worldwide. It remains incompletely understood in the real world how anti-viral therapy affects survival after HCC diagnosis. METHODS: This was an international multicentre cohort study of 2518 HBV-related HCC cases diagnosed between 2000 and 2015. Cox proportional hazards models were utilised to estimate hazard ratios (HR) with 95% (CI) for anti-viral therapy and cirrhosis on patients' risk of death. RESULTS: Approximately, 48% of patients received anti-viral therapy at any time, but only 17% were on therapy at HCC diagnosis (38% at US centres, 11% at Asian centres). Anti-viral therapy would have been indicated for >60% of the patients not on anti-viral therapy based on American criteria. Patients with cirrhosis had lower 5-year survival (34% vs 46%; P < 0.001) while patients receiving anti-viral therapy had increased 5-year survival compared to untreated patients (42% vs 25% with cirrhosis and 58% vs 36% without cirrhosis; P < 0.001 for both). Similar findings were seen for other patient subgroups by cancer stages and cancer treatment types. Anti-viral therapy was associated with a decrease in risk of death, whether started before or after HCC diagnosis (adjusted HR 0.62 and 0.79, respectively; P < 0.001). CONCLUSIONS: Anti-viral therapy improved overall survival in patients with HBV-related HCC across cancer stages and treatment types but was underutilised at both US and Asia centres. Expanded use of anti-viral therapy in HBV-related HCC and better linkage-to-care for HBV patients are needed.

Novel Deleterious Dihydropyrimidine Dehydrogenase Variants May Contribute to 5-Fluorouracil Sensitivity in an East African Population.

Clinical studies have identified specific genetic variants in dihydropyrimidine dehydrogenase (DPD; DPYD gene) as predictors of severe adverse toxicity to the commonly used chemotherapeutic 5-fluorouracil (5-FU); however, these studies have focused on European and European-American populations. Our laboratory recently demonstrated that additional variants in non-European haplotypes are predictive of 5-FU toxicity. The objective of this study was to identify potential risk variants in an understudied East African population relevant to our institution's catchment area. The DPYD protein-coding region was sequenced in 588 individuals of Somali or Kenyan ancestry living in central/southeast Minnesota. Twelve novel nonsynonymous variants were identified, seven of which significantly decreased DPD activity in vitro. The commonly reported toxicity-associated variants, *2A, D949V, and I560S, were not detected in any individuals. Overall, this study demonstrates a critical limitation in our knowledge of pharmacogenetic predictors of 5-FU toxicity, which has been based on clinical studies conducted in populations of limited diversity.

Histone acetyltransferase PCAF accelerates apoptosis by repressing a GLI1/BCL2/BAX axis in hepatocellular carcinoma.

P300/CBP-associated factor (PCAF), a histone acetyltransferase (HAT), has been found to regulate numerous cell signaling pathways controlling cell fate by acetylating both histone and non-histone proteins. We previously reported that PCAF upregulates cell apoptosis by inactivating Serine/Threonine Protein Kinase 1 (AKT1) signaling and consequently inhibits hepatocellular carcinoma (HCC) cell growth. Here, we show that PCAF can directly acetylate cytoplasmic GLI1 protein at lysine 518, preventing its nuclear translocation and promoter occupancy, and consequently suppressing Hedgehog (Hh) signaling in HCC. Further, our results show that GLI1 can increase Bcl-2 expression and downregulate BAX. Interestingly, forced expression of PCAF reduced Bcl-2 expression, upregulated BAX and repressed cell apoptosis. Further, we provide evidence that knockdown of GLI1 abrogates the inhibitory effect of PCAF on the growth of HCC in vitro. PCAF was also found to sensitize HCC cells to 5-fluorouracil (5-FU) treatment by regulating GLI1/Bcl-2/BAX axis-dependent apoptosis. In vivo experiments also confirmed the regulatory effect of PCAF on the GLI1/Bcl-2/BAX axis and its synergistic antitumor effects with 5-FU. Gene expression microarray studies showed that PCAF was downregulated in HCC tissues compared with adjacent liver tissues and that PCAF expression was significantly associated with longer overall survival and recurrence-free survival after surgery. Together, these results show that PCAF can induce cell apoptosis by modulating a GLI1/Bcl-2/BAX axis that in turn suppresses HCC progression, and suggest that 5-FU may exert a stronger anti-tumor effect in patients with PCAF expression in HCC tumors.

Mutations in isocitrate dehydrogenase 1 and 2 occur frequently in intrahepatic cholangiocarcinomas and share hypermethylation targets with glioblastomas.

Mutations in the genes encoding isocitrate dehydrogenase, IDH1 and IDH2, have been reported in gliomas, myeloid leukemias, chondrosarcomas and thyroid cancer. We discovered IDH1 and IDH2 mutations in 34 of 326 (10%) intrahepatic cholangiocarcinomas. Tumor with mutations in IDH1 or IDH2 had lower 5-hydroxymethylcytosine and higher 5-methylcytosine levels, as well as increased dimethylation of histone H3 lysine 79 (H3K79). Mutations in IDH1 or IDH2 were associated with longer overall survival (P=0.028) and were independently associated with a longer time to tumor recurrence after intrahepatic cholangiocarcinoma resection in multivariate analysis (P=0.021). IDH1 and IDH2 mutations were significantly associated with increased levels of p53 in intrahepatic cholangiocarcinomas, but no mutations in the p53 gene were found, suggesting that mutations in IDH1 and IDH2 may cause a stress that leads to p53 activation. We identified 2309 genes that were significantly hypermethylated in 19 cholangiocarcinomas with mutations in IDH1 or IDH2, compared with cholangiocarcinomas without these mutations. Hypermethylated CpG sites were significantly enriched in CpG shores and upstream of transcription start sites, suggesting a global regulation of transcriptional potential. Half of the hypermethylated genes overlapped with DNA hypermethylation in IDH1-mutant gliobastomas, suggesting the existence of a common set of genes whose expression may be affected by mutations in IDH1 or IDH2 in different types of tumors.

Prevention of hepatocellular carcinoma: progress and challenges.

Hepatocellular carcinoma (HCC) is a lethal cancer for both men and women and is caused by multiple risk factors. Most patients with HCC have an underlying liver disease caused by either chronic viral infection due to hepatitis B or hepatitis C virus or non-viral etiologic risk factors such as alcohol, fatty liver disease, dietary aflatoxin exposure, smoking and diabetes mellitus. While these risk factors are progressively and persistently damaging the liver, the majority of patients show very few symptoms of HCC. By the time symptoms appear the cancer is typically at a very advanced stage with limited options for treatment. In order to prevent death from HCC, it is therefore critically important to reduce the prevalence of the major risk factors, identify and treat those at high risk for development of HCC, and institute effective surveillance strategies for early diagnosis and treatment of HCC. This article reviews the recent progress and current challenges to the prevention of HCC.

Liver stiffness measurement by magnetic resonance elastography is not associated with developing hepatocellular carcinoma in subjects with compensated cirrhosis.

BACKGROUND: Liver stiffness assessed using transient elastography is described as a potential risk factor for hepatocellular carcinoma (HCC) in cirrhosis. However, the strict assessment of hepatic parenchymal areas uninvolved with HCC has not been investigated. AIM: To determine if liver stiffness of nonmalignant hepatic parenchyma using magnetic resonance elastography (MRE) is higher in patients with HCC compared with controls. METHODS: Cases were defined by compensated cirrhosis with a Child-Turcotte-Pugh score <7 and HCC by radiological criteria or histology. Control subjects with compensated cirrhosis were frequency matched with cases by gender and disease aetiology. Overt manifestations of portal hypertension and previous therapy for liver disease or HCC were exclusion criteria. Region of interest analyses were performed on hepatic parenchyma regions distant to HCC location among cases. RESULTS: Thirty patients with HCC and 60 matched controls comprised the study cohort. The mean age for cases was 64±10 years (range, 45-85) with 70% being men. Major disease aetiologies were chronic viral hepatitis (57%), non-alcoholic fatty liver disease (33%) and alcohol (10%). Twenty-eight (93%) patients had solitary HCC lesions with a mean size of 5.2 cm (range, 2-14 cm). However, patients with HCC had similar liver stiffness among uninvolved areas distant to HCC lesions, when compared with controls without HCC (mean, 6.1±2.0 vs. 6.3±2.5 kPa, P=0.7). CONCLUSION: In contrast to previous studies with transient elastography, we did not observe a systematic association between liver stiffness assessed using MRE and the presence of HCC in patients with compensated cirrhosis.

GLI3-dependent repression of DR4 mediates hedgehog antagonism of TRAIL-induced apoptosis.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis through its cognate receptors death receptor 4 (DR4) and death receptor 5 (DR5), preferentially in malignant cells. However, many malignant cells remain resistant to TRAIL cytotoxicity by poorly characterized mechanisms. Here, using cholangiocarcinoma cells, as a model for TRAIL resistance, we identified a role for the oncogenic Hedgehog (Hh)-GLI pathway in the regulation of TRAIL cytotoxicity. Blockade of Hh using pharmacological and genetic tools sensitizes the cells to TRAIL cytotoxicity. Restoration of apoptosis sensitivity coincided with upregulation of DR4 expression, while expression of other death effector proteins remained unaltered. Knockdown of DR4 mimics Hh-mediated resistance to TRAIL cytotoxicity. Hh regulates the expression of DR4 by modulating the activity of its promoter. Luciferase, chromatin immunoprecipitation and expression assays show that the transcription factor GLI3 binds to the DR4 promoter and Hh requires an intact GLI3-repression activity to silence DR4 expression. Finally, small interfering RNA (siRNA)-targeted knockdown of GLI3, but not GLI1 or GLI2, restores DR4 expression and TRAIL sensitivity, indicating that the Hh effect is exclusively mediated by this transcription factor. In conclusion, these data provide evidence of a regulatory mechanism, which modulates TRAIL signaling in cancer cells and suggest new therapeutic approaches for TRAIL-resistant neoplasms.

Prognostic role of vascular endothelial growth factor in hepatocellular carcinoma: systematic review and meta-analysis.

Hepatocellular carcinoma (HCC) is a highly vascular tumour that expresses vascular endothelial growth factor (VEGF). Various studies have evaluated the prognostic value of VEGF levels in HCC. Its overall test performance remains unclear, however. The aim was to perform a systematic review and meta-analysis of prognostic cohort studies evaluating the use of VEGF as a predictor of survival in patients with treated HCC. Eligible studies were identified through multiple search strategies. Studies were assessed for quality using the Newcastle-Ottawa Tool. Data were collected comparing disease-free and overall survival in patients with high VEGF levels as compared to those with low levels. Studies were pooled and summary hazard ratios were calculated. A total of 16 studies were included for meta-analysis (8 for tissue and 8 for serum). Methodological analysis indicated a trend for higher study quality with serum studies as compared to tissue-based investigations. Four distinct groups were pooled for analysis: tissue overall survival (n=251), tissue disease-free survival (n=413), serum overall survival (n=579), and serum disease-free survival (n=439). High tissue VEGF levels predicted poor overall (HR=2.15, 95% CI: 1.26-3.68) and disease-free (HR=1.69, 95% CI: 1.23-2.33) survival. Similarly, high serum VEGF levels predicted poor overall (HR=2.35, 95% CI: 1.80-3.07) and disease-free (HR=2.36, 95% CI 1.76-3.16) survival. A high degree of inter-study consistency was present in three of four groups analysed. Tissue and serum VEGF levels appear to have significant predictive ability for estimating overall survival in HCC and may be useful for defining prognosis in HCC.

A role for candidate tumor-suppressor gene TCEAL7 in the regulation of c-Myc activity, cyclin D1 levels and cellular transformation.

The pathophysiological mechanisms that drive the development and progression of epithelial ovarian cancer remain obscure. Recently, we identified TCEAL7 as a transcriptional regulatory protein often downregulated in epithelial ovarian cancer. However, the biological significance of such downregulation in cancer is not currently known. Here, we show that TCEAL7 is downregulated frequently in many human cancers and that in immortalized human ovarian epithelial cells this event promotes anchorage-independent cell growth. Mechanistic investigations revealed that TCEAL7 associates with cyclin D1 promoter containing Myc E-box sequence and transcriptionally represses cyclin D1 expression. Moreover, downregulation of TCEAL7 promotes DNA-binding activity of Myc-Max, and upregulates the promoter activity of c-Myc-target gene, ornithine decarboxylase (ODC), whereas enhanced expression of TCEAL7 inhibits Myc-induced promoter activity of ODC. Our findings suggest that TCEAL7 may restrict ovarian epithelial cell transformation by limiting Myc activity. These results also suggest a potential, alternative mechanism by which c-Myc activity may be deregulated in cancer by the downregulation of TCEAL7.

Epigenetic silencing of HSulf-1 in ovarian cancer:implications in chemoresistance.

To investigate the mechanism by which HSulf-1 expression is downregulated in ovarian cancer, DNA methylation and histone acetylation of HSulf-1 was analysed in ovarian cancer cell lines and primary tumors. Treatment of OV207 and SKOV3 by 5-aza-2'-deoxycytidine resulted in increased transcription of HSulf-1. Sequence analysis of bisulfite-modified genomic DNA from ovarian cell lines and primary tumors without HSulf-1 expression revealed an increase in the frequency of methylation of 12 CpG sites in exon 1A. Chromatin immunoprecipitation assays showed an increase in histone H3 methylation in cell lines without HSulf-1 expression. To assess the significance of HSulf-1 downregulation in ovarian cancer, OV167 and OV202 cells were transfected with HSulf-1 siRNA. Downregulation of HSulf-1 expression in OV167 and OV202 cells lead to an attenuation of cisplatin-induced cytotoxicity. Moreover, patients with ovarian tumors expressing higher levels of HSulf-1 showed a 90% response rate (27/30) to chemotherapy compared to a response rate of 63% (19/30) in those with weak or moderate levels (P=0.0146, chi(2) test). Collectively, these data indicate that HSulf-1 is epigenetically silenced in ovarian cancer and that epigenetic therapy targeting HSulf-1 might sensitize ovarian tumors to conventional first-line therapies.

Molecular targets for therapy of hepatitis B virus-induced hepatocellular carcinoma.

Chronic hepatitis B virus (HBV) infection is the most frequent risk factor for development of hepatocellular carcinoma (HCC) worldwide. Studies of the molecular genetics and pathophysiology of HCC suggest that there are significant differences in the allelic imbalance, genome copy number, and gene expression patterns of HBV-induced HCC as compared to HCCs from other causes, which are presumably reflected to differences in the mode of presentation and outcomes of HBV-induced HCCs. Unique features of HBV-induced carcinogenesis include the role of HBV DNA integration in carcinogenesis and the powerful synergism between HBV and dietary aflatoxins in the pathogenesis of HCC. A more complete understanding of the biology of HBV-induced HCCs may reveal well-defined differences in the molecular pathways that regulate growth of these HCCs and allow better-targeted approaches to prevention and therapy of HBV-induced HCCs. This review will attempt to summarize the current knowledge about carcinogenic pathways in HBV-induced HCCs, review the agents currently in development for targeted therapy of HCCs, and propose potentially novel approaches to therapy of HBV-induced HCC.

Integrations of the hepatitis B virus (HBV) and human papillomavirus (HPV) into the human telomerase reverse transcriptase (hTERT) gene in liver and cervical cancers.

Chronic infections with the hepatitis B virus (HBV) and high-risk human papillomaviruses (HPVs) are important risk factors for hepatocellular carcinoma (HCC) and cervical cancer (CC), respectively. HBV and HPV are DNA viruses that almost invariably integrate into the host genome in invasive tumors. The viral integration sites occur throughout the genome, leading to the presumption that there are no preferred sites of integration. A number of viral integrations have been shown to occur within the vicinity of important cancer-related genes. In studies of HBV-induced HCC and HPV-induced CC, we have identified two HBV and three HPV integrations into the human telomerase reverse transcriptase (hTERT) gene. Detailed characterization of the integrations revealed that four integrations occurred within the hTERT promoter and upstream region and the fifth integration occurred in intron 3 of the hTERT gene. None of the integrations altered the hTERT coding sequence and all resulted in juxtaposition of viral enhancers near hTERT, with potential activation of hTERT expression. Our work supports the hypothesis that the sites of oncogenic viral integration are nonrandom and that genes at the sites of viral integration may play important roles in carcinogenesis.

hMLH1 and hMSH2 expression in human hepatocellular carcinoma.

The role of microsatellite instability (MSI) in the pathogenesis of hepatocellular carcinoma (HCC) is incompletely defined. Although high-frequency MSI (MSI-H) is infrequently seen in HCC, some studies have suggested a role for MSI in HCC development. While MSI has been clearly defined for a subset of tumors, in particular colorectal, gastric and endometrial cancers, generally accepted criteria have not been developed for other tumors. Colorectal cancers (CRC) are classified as MSI-H if >30-40% of >5 microsatellite loci analyzed show instability. The MSI-H phenotype is associated with defective DNA mismatch repair (MMR) and is observed in the majority of tumors from patients with hereditary non-polyposis colon cancer (HNPCC) and also in 15% of sporadic CRCs. Inactivating mutations of the hMLH1 or hMSH2 genes lead to defects in MMR in HNPCC. In sporadic CRCs, MMR is usually due to hypermethylation of the hMLH-1 promoter. The role of defective MMR in hepatocellular carcinogenesis is controversial. Immunohistochemistry for hMLH1 and hMSH2 reliably indicates hMLH1 or hMSH2 loss in MSI-H CRC tumors. To investigate the role of defective MMR in HCC carcinogenesis, we performed immunohistochemistry for hMLH1 and hMSH2 on 36 HCCs. BAT26, a microsatellite marker that reliably predicts MSI-H was also examined. All 36 of the tumors stained positively for both hMLH1 and hMSH2, strongly suggesting an absence of either inactivating mutations of hMLH1 and hMSH2 or promoter hypermethylation of hMLH1. None of the tumors showed MSI at the BAT26 locus. These findings suggest that defective MMR does not contribute significantly to hepatocellular carcinogenesis.

The characterization of the common fragile site FRA16D and its involvement in multiple myeloma translocations.

Fragile sites appear as breaks, gaps, or decondensations on metaphase chromosomes when cells are grown under specific culture conditions. The breaks are nonrandom, appearing in defined, conserved locations throughout the mammalian genome. Common fragile sites, as their name implies, are present in virtually all individuals. With three common fragile sites cloned, their mechanism of expression and the role, if any, they play in human disease are still unclear. We have assembled a BAC contig of >1 Mb across the second most active common fragile site, FRA16D (16q23.2). We fluorescently labeled these BACs and used them as probes on metaphases from aphidicolin-induced lymphocytes and demonstrated that FRA16D decondensation/breakage occurs over a region of at least 1 Mb. Thus, this is the largest common fragile site cloned to date. Microsatellite markers that map within FRA16D show a very high loss in prostate, breast, and ovarian tumors, indicating that loss within this fragile site may be important in the development or progression of these tumors. In addition, a common t(14q32;16q23) translocation is observed in up to 25% of all multiple myelomas (MM). We localized four of four such cloned t(14;16) MM breakpoints within the FRA16D region. This work further demonstrates that the common fragile sites may play an important role in cancer development.

Pathophysiology of variceal bleeding.

A review of the pathophysiology of variceal bleeding, with a discussion of the pathogenesis of portal hypertension, formation of varices, and bleeding from varices. Portal hypertension results from increases in portal flow and portal vascular resistance. The factors increasing portal blood flow are primarily humoral. Resistance to portal flow has fixed and variable components. Elevated portal pressure leads to variceal formation. Variceal bleeding is dependent on portal pressure, variceal size, and variceal wall thickness.

Dysregulation of apoptosis as a mechanism of liver disease: an overview.

Apoptosis is a morphologically distinct form of cell death which occurs in a wide variety of liver diseases. In this overview chapter, we review: (1) the current definitions of apoptosis; (2) the biochemical pathways effecting apoptosis; and (3) the intracellular pathways regulating apoptosis. We also describe how apoptosis is identified in the liver and review the ligand/receptor interactions which trigger hepatobiliary apoptosis. Finally, we speculate on potential therapeutic applications for modulating apoptosis in human liver diseases. This information is meant to provide a foundation for the following chapters each focused on a specific role of apoptosis in liver diseases.