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.

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.

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.

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.

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.

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.

Abnormalities of sodium and H2O handling in chronic obstructive lung disease.

The pathogenesis of edema and hyponatremia in chronic obstructive lung disease (COLD), is poorly understood. Previously, in nonedematous patients with hypercapnia, small increases in plasma renin activity occurred, which prompted this study. In 25 hypercapnic, edematous, often hyponatremic patients with COLD, we measured renal hemodynamics, H2O, and sodium (Na+) excretion, plasma levels of renin activity (PRA), plasma levels of aldosterone (PA), and the plasma arginine vasopressin (AVP)-osmolality relationship. A high prevalence of elevated PRA, PA, and AVP levels excessively high for plasma osmolality was observed. Elevated PRA and Pa correlated with the inability to excrete Na+; an elevated AVP level correlated with the inability to excrete H2). These data suggest that, in conjunction with the hypercapnia-hypoxia-mediated disturbance in renal function, stimulation of the renin-aldosterone level and of the AVP systems contributes, respectively, to edema formation and to hyponatremia in advanced COLD.

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.

Coordinate transcriptional regulation of the three fibrinogen subunit genes by glucocorticoids in cultured primary liver cells from Xenopus laevis.

Xenopus laevis primary hepatocytes in culture are induced by glucocorticoid hormones to synthesize and secrete fibrinogen. The increase in production of the protein is preceded by a 10-to 30-fold elevation of the mRNAs coding for the three fibrinogen subunits, A alpha, B beta, and gamma. To analyze the mechanisms underlying this coordinate control of independent genes in a common regulatory network, we show here that the steroid hormone induced simultaneous activation of transcription of the three fibrinogen subunit genes. Using an optimized transcription run-on assay for nuclei from Xenopus primary liver cells, we demonstrate that glucocorticoids rapidly stimulated transcription of the A alpha fibrinogen subunit gene by 15- to 20-fold, the B beta gene by 5- to 10-fold, and the gamma gene by 5- to 15-fold. The three genes exhibited a highly concerted response to the hormone, in which maximal stimulation occurred by 30 min and was maintained for at least 16 h. Blocking new protein synthesis before hormone treatment reduced total transcription by 45% and partially inhibited specific hormonal induction of all three fibrinogen subunit genes. The effect of glucocorticoids on fibrinogen transcription, therefore, was dependent in part on ongoing protein synthesis, suggesting that hormonal stimulation uses already synthesized stable factors, but also requires labile or newly synthesized factors for the full effect.

cDNA and amino-acid sequences and organization of the gene encoding the B beta subunit of fibrinogen from Xenopus laevis.

Fibrinogen, the major blood-clotting protein, is made up of three chains, A alpha, B beta and gamma, which are synthesized and secreted by the liver. In this communication, we describe the complete cDNA sequence, deduced amino acid (aa) sequence and organization of the gene encoding the B beta subunit of fibrinogen from Xenopus laevis (Xl). The cDNA representing the predominant form of the B beta mRNA comprises 2390 nucleotides (nt), with an open reading frame of 1467 nt coding for a 488-aa protein. The percent identity between Xl B beta and that of other animals ranges from 50% for lamprey to 66% for human. The Xl B beta gene consists of nine exons, one more than found in the human gene. The exon/intron boundaries in the frog and human B beta genes are in exactly conserved positions, except for junctions in the highly variable fibrinopeptide-encoding regions. Three of the exon/intron boundaries in the Xl B beta gene are also analogous to ones in A alpha and gamma genes of other species, supporting the notion of a close evolutionary relationship between the genes for all three subunits. This analysis of B beta from an amphibian provides the first complete description of the arrangement of exons and introns in any fibrinogen subunit gene from a non mammal and gives insight into the most highly conserved aspects of fibrinogen protein structure and gene organization.

Molecular cloning of cDNA for the B beta subunit of Xenopus fibrinogen, the product of a coordinately-regulated gene family.

Fibrinogen, the principal blood-clotting protein, is made up of three different subunits synthesized in the liver. In vitro administration of glucocorticoids to liver cells from the frog Xenopus laevis causes a dramatic increase in fibrinogen synthesis. Investigations of molecular mechanisms underlying this hormonal stimulation at the mRNA level require cDNA clones complementary to the mRNAs coding for the three fibrinogen subunits, called A alpha, B beta, and gamma. We describe here the isolation and characterization of cDNA clones for the B beta subunit of Xenopus fibrinogen. cDNA libraries in both plasmid (pBR322) and phage (lambda gt10) cloning vectors were constructed from frog liver mRNA and screened with a rat B beta cDNA. Clones thus isolated hybridized to two Xenopus liver mRNAs 2500 and 1800 bases long, the previously-determined sizes for B beta mRNAs. The identity of the plasmid clone B beta-27 was confirmed by hybridization-selection of complementary mRNA which translated in vitro into the B beta polypeptide, as determined by size and susceptibility to thrombin cleavage. lambda/B beta 10, a clone representing nearly all of the 2500-base B beta mRNA, was isolated from the phage cDNA library. The 3'-end of this clone includes a polyadenylation signal about 20 residues upstream of a stretch of 34 adenosine residues, which probably represents the 3'-poly(A) tail of the messenger RNA. lambda/B beta 10 lacks only 20 nucleotides of full-length B beta mRNA at the 5'-end and there is one major start site of transcription. The 2500-base B beta mRNA has a 700-base extension at the 3'-end that is not present in the 1800-base mRNA. The Xenopus laevis genome contains two or three genes for the B beta fibrinogen subunit. Using the cDNA clone as a probe, B beta mRNA was shown to be induced at least 20-fold by glucocorticoid treatment of purified parenchymal cells of Xenopus liver maintained in primary culture.

Pathophysiology and treatment of variceal hemorrhage.

Portal hypertension results from increases in portal flow and portal vascular resistance. Factors increasing portal blood flow are predominantly humoral. Resistance to portal flow has a fixed component due to distortion of the vasculature by cirrhotic nodules and a variable component that is related to vasoactive substances. Varices result from an increase in portal pressure. Factors predicting the risk of variceal bleeding include continued alcohol use, poor liver function, large varices, and red wale markings on varices at endoscopy. Octreotide is probably the drug of choice for pharmacologic management of bleeding esophageal varices. Propranolol has an established role in the prevention of variceal hemorrhage, and variceal band ligation may be the preferred endoscopic technique. Transjugular intrahepatic portosystemic shunts have emerged as an important treatment for patients in whom pharmacologic and endoscopic therapies have failed and are an effective bridge to liver transplantation.

Ascites and hepatorenal syndrome: pathophysiology and management.

Ascites, a late manifestation of cirrhosis of the liver, causes increased morbidity and mortality. The renin-angiotensin-aldosterone system, the sympathetic nervous system, and arginine vasopressin are responsible for sodium and water retention in patients with cirrhosis. Fluid localizes to the peritoneal cavity mainly as a result of portal hypertension. Recent developments in the understanding of the pathophysiologic mechanisms of ascites include the role of inadequate renal prostaglandin production in the development of the hepatorenal syndrome and the possible role of nitric oxide in the pathogenesis of the renal complications of cirrhosis. The aim of medical therapy is to achieve a negative sodium balance and, consequently, fluid loss. Large-volume paracentesis is safe and effective in the management of tense ascites, but use of diuretic agents should be continued to prevent reaccumulation of ascites. Liver transplantation, transjugular intrahepatic portosystemic shunts, or LeVeen shunts should be considered in selected patients with persistent ascites. In patients with diuretic-resistant or diuretic-refractory ascites, a thorough assessment must be performed to exclude potentially reversible causes. The hepatorenal syndrome has an associated grave prognosis, especially in patients who are not candidates for liver transplantation.

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.

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.

New evaluation of potential methylmercury scavengers.

A biological assay was developed to evaluate rapidly the relative efficacy of marketed and experimental mercurial scavengers. Rat liver mitochondrial protein (1.0 mg) was titrated against methyl-mercuric chloride to the inhibitory level of mitochondrial respiration. Respiration induced by adenosine 5'-diphosphate with succinate (plus rotenone) as the substrate was inhibited consistently by 20.7 +/- 3.9 nmoles of methylmercury/mg of protein. Adenosine 5'-diphosphate-stimulated respiration (State 3) was restored with dimercaprol, penicillamine, and cysteine but not with serine. The antagonists glutathione, 3-mercapto-propionic acid, 2-mercaptoethanol, dithiothreitol, thioglucose, mercaptosuccinic acid, and thiosalicylic acid and mercaptosuccinic acid. Sodium sulfide, thioacetamide, and ethylenediaminetetraacetic acid were completely inactive. Substitution of glutamate (plus malate) for succinate (plus rotenone) as the substrate did not alter the responses significantly. The rat liver mitochondrial assay provides preliminary information about the efficacy and toxicity of water-soluble thiols. Investigations utilizing encapsulated water- and lipid-soluble mercaptans are in progress.

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.