Metabolic liver cancer: associations of rare and common germline variants in one-carbon metabolism and DNA methylation genes

Animal studies implicate one-carbon metabolism and DNA methylation genes in hepatocellular carcinoma (HCC) development in the setting of metabolic perturbations. Using human samples, we investigated the associations between common and rare variants in these closely related biochemical pathways and risk for metabolic HCC development in a multicenter international study. We performed targeted exome sequencing of 64 genes among 556 metabolic HCC cases and 643 cancer-free controls with metabolic conditions. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for multiple comparisons. Gene-burden tests were used for rare variant associations. Analyses were performed in the overall sample and among non-Hispanic whites. The results show that among non-Hispanic whites, presence of rare functional variants in ABCC2 was associated with 7-fold higher risk of metabolic HCC (OR = 6.92, 95% CI: 2.38-20.15, P = 0.0004), and this association remained significant when analyses were restricted to functional rare variants observed in ≥2 participants (cases 3.2% versus controls 0.0%, P = 1.02 × 10-5). In the overall multiethnic sample, presence of rare functional variants in ABCC2 was nominally associated with metabolic HCC (OR = 3.60, 95% CI: 1.52-8.58, P = 0.004), with similar nominal association when analyses were restricted to functional rare variants observed in ≥2 participants (cases 2.9% versus controls 0.2%, P = 0.006). A common variant in PNPLA3 (rs738409[G]) was associated with higher HCC risk in the overall sample (P = 6.36 × 10-6) and in non-Hispanic whites (P = 0.0002). Our findings indicate that rare functional variants in ABCC2 are associated with susceptibility to metabolic HCC in non-Hispanic whites. PNPLA3-rs738409 is also associated with metabolic HCC risk.

GPR15-mediated T cell recruitment during acute viral myocarditis is associated with improved virus elimination and outcome

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK

Ernst und Berta Grimmke Stiftung

Background

Myocarditis is an inflammatory disease of the myocardium indicated by mononuclear cell infiltration. It is predominantly caused by infectious agents such as coxsackievirus B3 (CVB3). Especially in young adults, myocarditis is a major source of sudden cardiac arrest. However, its clinical course has a broad spectrum of outcomes, ranging from mild symptoms and complete recovery to cardiac dysfunction and dilated cardiomyopathy. G protein-coupled receptor 15 (GPR15) was identified as a T cell homing receptor in the context of inflammatory intestine and skin diseases. We found Gpr15 to be highly upregulated in the left ventricle (LV) 7 days after CVB3 infection in wild type (WT) mice.

Purpose

GPR15 has not been described in a cardiac context, yet. Our aim was to investigate the role of GPR15 in recruiting immune cell subsets and later in virus elimination during viral myocarditis.

Methods

Gpr15 deficient (Gpr15gfp/gfp) and WT mice were infected intraperitoneal with CVB3 to investigate the acute (6 & 7 days post infection(p.i.)) and the subacute phase (16 days p.i.) of myocarditis. To study differentially expressed genes, LV tissue was used for TaqMan analysis and RNA-sequencing. Inflammation and fibrosis were evaluated on histological level. For functional characterization, healthy and diseased mice were hemodynamically characterized 16 days p.i.. Furthermore, in vitro migration assays were used to study the interaction between GPR15 and its ligands in vitro.

Results

Infected Gpr15gfp/gfp mice exhibited higher upregulation of immune response related genes on mRNA level in the acute phase of myocarditis 7 days p.i.. For instance, Cd8a, a cytotoxic T cell marker, and Foxp3, a regulatory T cell marker, were significantly higher in infected Gpr15gfp/gfp compared to infected WT mice. Bulk RNA-sequencing confirmed that the response to virus did not decline from day 6 to 7 in infected GPR15-deficient mice as observed in infected WT mice. Subsequent gene ontology (GO) term analyses reveled enhanced chemotaxis and cytotoxic T cell-related GO terms in GPR15-deficient mice on day 7.

Among investigated T cell subsets, GPR15 was highest expressed on CD8+ T cell. Its deficiency abolished chemotaxis of T cells, especially of cytotoxic T cells, towards GPR15 ligand in vitro.

In the subacute phase of myocarditis 16 days p.i., viral persistence was observed in more than 85 % of Gpr15gfp/gfp mice. In contrast, more than 70 % of WT mice with verified viremia cleared the virus successfully. Furthermore, Gpr15gfp/gfp mice demonstrated a decreased cardiac function accompanied by increased fibrosis in comparison to WT mice.

Conclusion

Our findings indicate that despite the prolonged inflammatory response, scant virus elimination was presumably caused by decelerated recruitment of cytotoxic T cells leading to impaired outcome in the GPR15-deficient mice.

Extracellular RNA transfer from non-malignant human cholangiocytes can promote cholangiocarcinoma growth

Extracellular vesicles (EV) within the cellular secretome are emerging as modulators of pathological processes involved in tumor growth through their ability to transfer donor‐derived RNA into recipient cells. While the effects of tumor and stromal cell EVs within the tumor microenvironment have been studied, less is known about the contributions of normal, nontransformed cells. We examined the impact of EVs within the cellular secretome from nonmalignant cells on transformed cell growth and behavior in cholangiocarcinoma cells. These effects were enhanced in the presence of the pro‐fibrogenic mediator TGF‐β. We identified miR‐195 as a TGF‐β responsive miRNA in normal cells that can be transferred via EV to tumor cells and regulate cell growth, invasion, and migration. The effects of miR‐195 involve modulation of the epithelial–mesenchymal transition through direct effects on the transcription factor Snail. These studies provide in vitro and in vivo evidence for the impact of normal cellular secretome on transformed cell growth, show the importance of EV RNA transfer, and identify mechanisms of EV‐mediated transfer of miRNA as a contributor to tumor development, which may provide new therapeutic opportunities for targeting human cholangiocarcinoma.

Presentation characteristics, use of treatments and outcomes in patients with ischaemic vs. non-ischaemic cardiogenic shock

Aim

Evidence on non-ischaemic cardiogenic shock (CS) is scarce. The aim of this study was to investigate differences in presentation characteristics, use of treatments and outcomes in patients with ischaemic vs. non-ischaemic CS.

Methods

Patients with CS admitted to a tertiary care hospital between October 2009 and October 2017 were identified and stratified as ischaemic CS/non-ischaemic CS based on the presence/absence of acute myocardial infarction. Missing data was handled by chained equation multiple imputation. Logistic and Cox regression models were fitted to investigate the association of non-ischaemic CS with presentation characteristics (adjusted for all baseline variables), and use of treatments as well as30-day in-hospital mortality (adjusted for relevant confounders including age, sex, prior cardiac arrest, haemodynamics, pH and lactate).

Results

A total of 978 patients were enrolled in this study; median age was 70 (interquartile range 58, 79) years and 70% were male. 505 patients (43%) had non-ischaemic CS. Patients with non-ischaemic CS were more likely younger and female; were less likely to be active smokers or to have diabetes, but more likely to have chronic renal disease and history of myocardial infarction; and were more likely to present with unfavourable haemodynamics and with mechanical ventilation. Regarding use of treatments, patients with non-ischaemic CS were more likely to be treated with catecholamines [odds ratio (OR) 1.58, 95% confidence interval (CI) 1.11–2.27, p0.01], but less likely to be treated with extracorporeal membrane oxygenation (OR 0.66, 95% CI 0.48–0.92, p=0.02) or percutaneous left ventricular assist devices (OR 0.51, 0.35–0.74, p<0.01). Unadjusted survival probabilities in patients with non-ischaemic vs. ischaemic CS were 36% (95% CI 32–42%) vs. 39% (95% CI 35–45%). After adjustment for multiple relevant confounders, non-ischaemic CS was associated with a significant increase in the risk of 30-day in-hospital mortality (hazard ratio 1.30, 95% CI 1.09–1.55, p<0.01, Figure 1).

Conclusion

In this large study, non-ischaemic CS accounted for almost 50% of all CS cases. Non-ischaemic CS was not only associated with relevant differences in presentation characteristics and use of treatments, but also with a worse prognosis. These findings highlight the need for effective treatment strategies for patients with non-ischaemic CS.

Figure 1

Funding Acknowledgement

Type of funding source: None

P1642High-sensitivity cardiac troponin I and NT-proBNP and their relationship to heart failure in the European BiomarCaRE population

Aims

Heart failure (HF) is an increasingly important contributor to the overall burden of cardiovascular disease in the population. We aimed to determine the distribution of the cardiac biomarkers high-sensitivity cardiac troponin I (hs-cTnI) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentrations across the European population to characterize the association with incident HF.

Methods and results

Based on the Biomarkers for Cardiovascular Risk Assessment in Europe (BiomarCaRE)-project, we analysed data of 48,455 individuals from four prospective population-based cohort studies (DanMONICA, FINRISK, Moli-Sani, Northern Sweden MONICA study) across Europe with a maximum follow-up of 27 years. The median age of the participants was 50.7 years (25th percentile: 40.0 years, 75th percentile: 61.7 years) and 49.1% (25,146) were men. Considered endpoints were incident HF and all-cause mortality. The median follow-up time for occurrence of HF was 6.61 (6.55; 6.66) years. We found that cardiovascular risk factors (CVRFs), especially diabetes with HR of 2.11 (95% CI 1.8, 2.5) and smoking status with HR of 1.79 (95% CI 1.59, 2.1) (Figure 1) were associated with incident HF. Furthermore, beyond the CVRFs, elevated hs-cTnI and NT-proBNP concentrations contributed to risk of HF in the general population with HR of 1.49 (95% CI 1.21, 1.9) and HR of 2.37 (95% CI 1.97, 3.0) respectively. As a cut-off value to select individuals, who would benefit most from preventive strategies, a hs-cTnI concentration of 2.8 ng/L was calculated using the optimal cut-off methodology by Contal and O'Quigley in CSDA 1999.

Hazard ratio for incident HF

Conclusion

In our large population-based cohort, hs-cTnI and NT-proBNP were independently associated with incident HF. Use of biomarkers for HF screening thus may help to select those individuals in the general population who would benefit most from preventive strategies. Based on the cut-off value future studies are needed to evaluate therapeutic options.

Long noncoding RNA in liver diseases

The identification of the presence of large RNA transcripts that do not code for proteins but that may have biological functions has provided an important new perspective in gene regulation. These long noncoding RNAs (lncRNAs) are being increasingly recognized to contribute to many biological processes through diverse mechanisms. The roles of these emerging genes are being recognized across kingdoms. These findings are profoundly altering our understanding of disease pathobiology and leading to the emergence of new biological concepts underlying human diseases. Strategies for the discovery and characterization of lncRNAs are highlighted. Several lncRNAs have been described in liver disease, and in liver cancers in particular. Their molecular mechanisms of action, function, and contributions to disease pathophysiology are reviewed. LncRNA genes associated with liver diseases have potential roles as biomarkers of disease diagnosis, prognosis, or therapeutic response as well as direct targets for therapeutic intervention.

CONCLUSION

The emerging knowledge in this rapidly advancing field offers promise for new fundamental knowledge and clinical applications that will be relevant for human liver diseases.

Hepatic miR-29ab1 expression modulates chronic hepatic injury

MicroRNAs (miRNAs) are small, regulatory non-coding RNAs that have potent effects on gene expression. Several miRNA are deregulated in cellular processes involved in human liver diseases and regulation of cellular processes. Recent studies have identified the involvement of miR-29 in hepatic fibrosis and carcinogenesis. Although several targets of miR-29 have been identified, there is limited information regarding the cell-type specific roles of miR-29 in the liver, and we sought to evaluate the role of this miRNA in hepatic pathobiology. We report the generation of a tissue–specific knockout mouse to evaluate the role of miR-29 in hepatic fibrosis and carcinogenesis in response to injury. We hypothesized that miR-29 contributes to the hepatocyte driven response to chronic cellular injury that results in fibrosis. In support of this hypothesis, fibrosis and mortality were enhanced in miR29 knockout mice in response to carbon tetrachloride. Genome-wide gene expression analysis identified an over-representation of genes associated with fibrosis. The oncofetal RNA H19 was modulated in a miR-29 dependent manner following exposure to carbon tetrachloride in vivo. The impact of a hepatocyte specific miR-29 knockout on survival following chronic hepatic injury in vivo implicates this miRNA as a potential target for intervention. These results provide evidence of the involvement of miR-29 in chronic hepatic injury, and suggest a role for deregulated hepatocyte expression of miR-29 in the response to hepatic injury, fibrosis and carcinogenesis.

Emerging insights into the role of microRNAs in the pathogenesis of cholangiocarcinoma

The microRNAs (miRNAs) are small noncoding RNAs that are potent regulators of gene expression and can regulate several diverse biological functions. This minireview provides an overview of recent studies that have examined the role and involvement of miRNAs in cholangiocarcinomas. These studies provide evidence for deregulated expression of miRNA and are providing new insights into the potential contribution of these in the pathogenesis of cholangiocarcinoma.

Therapeutic potential of the translation inhibitor silvestrol in hepatocellular cancer

BACKGROUND & AIMS

Although hepatocellular cancers (HCC) frequently arise in the setting of fibrosis and a hepatic regenerative response requiring new cell growth, therapeutic strategies for these cancers have not targeted protein synthesis. Silvestrol, a rocaglate isolated from Aglaiafoveolata, can inhibit protein synthesis by modulating the initiation of translation through the eukaryotic initiation factor 4A. In this study, we evaluated the therapeutic efficacy of silvestrol for HCC.

METHODS

The efficacy of silvestrol was examined using human HCC cells in vitro using an orthotopic tumor cell xenograft model in a fibrotic liver. The impact of silvestrol on the liver was assessed in vivo in wild-type mice.

RESULTS

Silvestrol inhibited cell growth with an IC50 of 12.5-86 nM in four different HCC cell lines. In vitro, silvestrol increased apoptosis and caspase 3/7 activity accompanied by loss of mitochondrial membrane potential and decreased expression of Mcl-1 and Bcl-xL. A synergistic effect was observed when silvestrol was combined with other therapeutic agents, with a dose-reduction index of 3.42-fold with sorafenib and 1.75-fold with rapamycin at a fractional effect of 0.5. In vivo, an antitumor effect was observed with 0.4 mg/kg silvestrol compared to controls after one week, and survival of tumor-bearing mice was improved with a median survival time of 42 and 28 days in the silvestrol and control groups, respectively. The effect on survival was not observed in orthotopic xenografts in non-fibrotic livers. Silvestrol treatment in vivo did not alter liver structure.

CONCLUSIONS

These data identify silvestrol as a novel, structurally unique drug with potent anticancer activity for HCC and support the potential value of targeting initiation of translation in the treatment of HCC.

microRNAs in liver disease: from diagnostics to therapeutics

There is a need to identify effective biomarkers for diagnosis, prognosis and prediction of treatment efficacy for many liver diseases such as hepatocellular cancer, and chronic viral hepatitis. The identification of disease-specific alterations in microRNA expression and the ability to detect microRNAs in the circulation provide the basis for identifying novel clinically effective treatments and biomarkers. Knowledge regarding miRNA in human liver disease may eventually lead to serum or tissue biomarkers with clinical utility. A selection of relevant studies is reviewed. There are major challenges that need to be addressed prior to clinical application such as the need for careful validation of diagnostic miRNA candidates in well described clinical cohorts, and technical issues such as quantitation and standardization of assays. The rapid progress in therapeutic interventions using miRNA based strategies for chronic hepatitis C and hepatocellular cancer provides optimism for novel approaches that will build on the existing and emerging knowledge regarding miRNA in liver diseases.

microRNAs in liver disease: from diagnostics to therapeutics

There is a need to identify effective biomarkers for diagnosis, prognosis and prediction of treatment efficacy for many liver diseases such as hepatocellular cancer, and chronic viral hepatitis. The identification of disease-specific alterations in microRNA expression and the ability to detect microRNAs in the circulation provide the basis for identifying novel clinically effective treatments and biomarkers. Knowledge regarding miRNA in human liver disease may eventually lead to serum or tissue biomarkers with clinical utility. A selection of relevant studies is reviewed. There are major challenges that need to be addressed prior to clinical application such as the need for careful validation of diagnostic miRNA candidates in well described clinical cohorts, and technical issues such as quantitation and standardization of assays. The rapid progress in therapeutic interventions using miRNA based strategies for chronic hepatitis C and hepatocellular cancer provides optimism for novel approaches that will build on the existing and emerging knowledge regarding miRNA in liver diseases.