Hepatitis C virus infection triggers a tumor-like glutamine metabolism.

Chronic infection with hepatitis C virus (HCV) is one of the main causes of hepatocellular carcinoma. However, the molecular mechanisms linking the infection to cancer development remain poorly understood. Here we used HCV-infected cells and liver biopsies to study how HCV modulates the glutaminolysis pathway, which is known to play an important role in cellular energetics, stress defense, and neoplastic transformation. Transcript levels of glutaminolytic factors were quantified in Huh7.5 cells or primary human hepatocytes infected with the Japanese fulminant hepatitis 1 HCV strain as well as in biopsies of chronic HCV patients. Nutrient deprivation, biochemical analysis, and metabolite quantification were performed with HCV-infected Huh7.5 cells. Furthermore, short hairpin RNA vectors and small molecule inhibitors were used to investigate the dependence of HCV replication on metabolic changes. We show that HCV modulates the transcript levels of key enzymes of glutamine metabolism in vitro and in liver biopsies of chronic HCV patients. Consistently, HCV infection increases glutamine use and dependence. We finally show that inhibiting glutamine metabolism attenuates HCV infection and the oxidative stress associated with HCV infection. CONCLUSION: Our data suggest that HCV establishes glutamine dependence, which is required for viral replication, and, importantly, that glutamine addiction is a hallmark of tumor cells. While HCV induces glutaminolysis to create an environment favorable for viral replication, it predisposes the cell to transformation. Glutaminolytic enzymes may be interesting therapeutic targets for prevention of hepatocarcinogenesis in chronic hepatitis C. (Hepatology 2017;65:789-803).

Micro RNAs mir-106a, mir-122 and mir-197 are increased in severe acute viral hepatitis with coagulopathy.

BACKGROUND & AIMS: The severity of acute viral hepatitis, which may be caused by several distinct viruses, varies among individual patients. In rare cases, severe hepatic injury with sudden loss of liver function may occur, which is clinically indicated by the occurrence of coagulopathy or encephalopathy. As the molecular mechanisms of this liver injury are largely unknown, we investigated extracellular micro RNA (miRNA) profiles in 54 patients acutely infected with one of four different hepatotropic viruses, in order to identify those miRNAs which indicate severe viral hepatitis associated with coagulopathy. METHODS: First, the profile of miRNAs was extensively analysed using a microarray-based approach in highly characterized 24 patients, matched in terms of sex, age and level of liver enzymes, as well as in three healthy controls. The cohort included samples from 18 patients with moderate and six individuals with severe hepatitis, indicated by abnormal prothrombin time and higher alanine aminotransferase and bilirubin levels. miRNAs found to be upregulated in severe hepatitis were then quantified by real-time PCR in the expanded cohort of 54 patients. RESULTS: Comprehensive microarray-based miRNA profiling identified upregulation of mir-106a, mir-122 and mir-197 in patients with severe acute viral hepatitis with coagulopathy, as compared to patients who did not develop coagulopathy. mir-106a, mir-122 and mir-197 were then proven to be significantly upregulated in patients with severe acute viral hepatitis by quantitative real-time PCR (P < 0.01, Mann-Whitney U-test). CONCLUSIONS: mir-106a, mir-122 and mir-197 could be potential markers for severe acute viral hepatitis associated with coagulopathy.

Control of mitogenic and motogenic pathways by miR-198, diminishing hepatoma cell growth and migration.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths, worldwide. MicroRNAs, inhibiting gene expression by targeting various transcripts, are involved in genomic dysregulation during hepatocellular tumorigenesis. In previous studies, microRNA-198 (miR-198) was shown to be significantly downregulated in HCV-positive hepatocellular carcinoma (HCC). Herein, the function of miR-198 in hepatocellular carcinoma cell growth and gene expression was studied. In hepatoma cell-types with low levels of liver-specific transcription factor HNF1α indicating a low differentiation grade, miR-198 expression was most downregulated. However, miR-198 treatment did not restore the expression of the liver-specific transcription factors HNF1α or HNF4α. Importantly, overexpression of miR-198 in Pop10 hepatoma cells markedly reduced cell growth. In agreement, comprehensive gene expression profiling by microarray hybridisation and real-time quantification revealed that central signal transducers of proliferation pathways were downregulated by miR-198. In contrast, genes mediating cellular adherence were highly upregulated by miR-198. Thus, the low expression of E-cadherin and claudin-1, involved in cell adhesion and cell-cell contacts, was abolished in hepatoma cells after miR-198 overexpression. This definite induction of both proteins by miR-198 was shown to be accompanied by a significantly impaired migration activity of hepatoma Pop10 cells. In conclusion, miR-198 acts as a tumor suppressor by repression of mitogenic and motogenic pathways diminishing cell growth and migration.

ESR1-promoter-methylation status in primary breast cancer and its corresponding metastases.

The role of ESR1 methylation in breast cancer and its influence on disease progression is not yet fully understood. Healthy breast tissue usually does not show ESR1 promoter methylation, whereas the frequency of ESR1 methylation appears to increase in primary breast cancer and in metastatic disease. Although women with ER positive breast cancer have a good prognosis, some will relapse. We aimed to evaluate the methylation status of ESR1 in primary breast cancer and its corresponding metastases by a methylation-specific real-time PCR and to correlate the methylation status with clinical outcome. Women who were treated for primary and metastatic breast cancer were included in the study. Tumor DNA was isolated from paraffin embedded tissue sections. After bisulfite treatment ESR1 promoter methylation was analyzed by real time-MSP of each tissue sample. Kaplan-Meier-Curves were drawn for survival. In the group of patients with positive ESR1 promoter methylation in the primary breast carcinoma survival was lower compared to the group of patients without methylation (38.1 months vs. 54.3 months, n.s.). Seven out of 19 (37%) of those patients with positive ESR1 promoter methylation developed loss of ER expression in metastatic disease. None of the patients who had primary tumours that were ESR1 methylation negative developed ER expression negative metastatic disease. The results underline the importance of the ESR1 promoter methylation and its potential application as a predictive marker. To improve the clinical outcome of patients with metastatic disease, those with initially positive ESR1 methylation status should undergo a tissue biopsy already at the beginning of metastatic disease to identify those with loss of ER expression and thus resitance to anti-endocrine therapy.

Evolution analysis of heterogeneous non-small cell lung carcinoma by ultra-deep sequencing of the mitochondrial genome.

Accurate assessment of tumour heterogeneity is an important issue that influences prognosis and therapeutic decision in molecular pathology. Due to the shortage of protective histones and a limited DNA repair capacity, the mitochondrial (mt)-genome undergoes high variability during tumour development. Therefore, screening of mt-genome represents a useful molecular tool for assessing precise cell lineages and tracking tumour history. Here, we describe a highly specific and robust multiplex PCR-based ultra-deep sequencing technology for analysis of the whole mt-genome (wmt-seq) on low quality-DNA from formalin-fixed paraffin-embedded tissues. As a proof of concept, we applied the wmt-seq technology to characterize the clonal relationship of non-small cell lung cancer (NSCLC) specimens with multiple lesions (N = 43) that show either different histological subtypes (group I) or pulmonary adenosquamous carcinoma as striking examples of a mixed-histology tumour (group II). The application of wmt-seq demonstrated that most samples bear common mt-mutations in each lesion of an individual patient, indicating a single cell progeny and clonal relationship. Hereby we show the monoclonal origin of histologically heterogeneous NSCLC and demonstrate the evolutionary relation of NSCLC cases carrying heteroplasmic mt-variants.

Circulating miRNA-122 levels are associated with hepatic necroinflammation and portal hypertension in HIV/HCV coinfection.

BACKGROUND: Introduction of combined antiretroviral therapy (cART) has improved survival of HIV infected individuals, while the relative contribution of liver-related mortality increased. Especially in HIV/HCV-coinfected patients hepatic fibrosis and portal hypertension represent the main causes of liver-related morbidity and mortality. Circulating miRNA-122 levels are elevated in HIV patients and have been shown to correlate with severity of liver injury. However, the association of miRNA-122 levels and hepatic fibrosis and portal hypertension remains to be explored in HIV/HCV coinfection. METHODS: From a total of 74 (31% female) patients with HIV/HCV coinfection were included. Serum levels of miRNA-122 were analyzed by quantitative polymerase chain reaction (PCR) and normalized to SV-40 spike-in RNA. Hepatic venous pressure gradient (HVPG) was measured in 52 (70%) patients and the fibrosis stage was determined in 63 (85%) patients using transient elastography. RESULTS: The levels of circulating miRNA-122 were increased in HIV/HCV coinfected patients and significantly correlated with the alanine aminotransferase (ALT) (rs = 0.438; p<0.001) and aspartate transaminase AST values (rs = 0.336; p = 0.003), but not with fibrosis stage (p = n.s.). Interestingly, miRNA-122 levels showed an inverse correlation with hepatic venous pressure gradient (HVPG) (rs = -0.302; p = 0.03). CONCLUSION: Elevated miRNA-122 levels are associated with liver injury, and with low HVPG. Though, miRNA-122 levels are not suitable to predict the degree of fibrosis, they might function as indicators for portal hypertension in HIV/HCV coinfected patients.

The role of miRNA-34a as a prognostic biomarker for cirrhotic patients with portal hypertension receiving TIPS.

BACKGROUND: Circulating miRNA-34a is increased in blood of patients with different liver diseases when compared to healthy controls. However, the origin of miRNA-34a and its possible relationship with hemodynamics and outcome in cirrhotic patients with portal hypertension is unknown. We analyzed the levels of miRNA-34a in cirrhotic patients with severe portal hypertension. METHODS: We included 60 cirrhotic patients receiving TIPS for prevention of rebleeding and/or therapy-refractory ascites. miRNA-34a levels were measured using qPCR and normalized by SV-40 in the portal and hepatic venous blood of these patients taken at TIPS procedure. Hemodynamic and clinical parameters were assessed before TIPS and during follow-up. RESULTS: Levels of miRNA-34a were higher in the hepatic vein than in the portal vein. Circulating miRNA-34a in the hepatic vein correlated with ALT, CHE and sodium excretion after TIPS. miRNA-34a showed no correlation with portal pressure, but its levels in the portal vein correlated inversely with the congestion index. Interestingly, the levels of miRNA-34a in the portal and hepatic vein showed inverse correlation with arterial pressure. Furthermore, levels of miRNA-34a in the hepatic vein had a predictive value for survival, but MELD, creatinine at short-time follow-up 14 days after TIPS-insertion and portal pressure after TIPS performed better. CONCLUSION: This study demonstrates for the first time, that miRNA-34a may originate to a large extent from the liver. Even though higher levels of miRNA-34a are possibly associated with better survival at long-term follow-up in cirrhotic patients with severe portal hypertension receiving TIPS, classical prognostic parameters predict the survival better.