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

Abstract 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

SQSTM1/p62 promotes miR-198 loading into extracellular vesicles and its autophagy-related secretion

MicroRNA dysregulation is a hallmark of hepatocellular carcinoma (HCC), leading to tumor growth and metastasis. Previous screening on patient specimens identified miR-198 as the most downregulated miRNA in HCC. Here, we show that miR-198 compensation leads to self-release into extracellular vesicles (EVs). Importantly, the vesicular secretion is mediated by autophagy-related pathway, initiated by sequestration of p62/miR-198 complexes in autophagosome-associated vesicle fractions. miR-198 is selectively recognized and loaded by p62 into autophagosomal fractions, whereas mutated miR-198 forms neither induce autophagy and nor interact with p62. Gain and loss of function experiments, using a CRIPR/Cas knockout (KO) and transgenic site-specific p62 mutants, identified p62 as an essential repressor of cellular miR-198 abundancy. Notably, EVs, harboring miR-198/p62 protein complexes, can be uptaken by cells in the close vicinity, leading to change of gene expression in recipient cells. In conclusion, miR-198 enhances autophagy; conversely autophagic protein p62 reduces the miR-198 levels by sorting into extracellular space. [GRAPHICS]

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 (38.1months vs. 54.3months, 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

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

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

Background & AimsThe 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. MethodsFirst, 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. ResultsComprehensive 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). Conclusionsmir-106a, mir-122 and mir-197 could be potential markers for severe acute viral hepatitis associated with coagulopathy

LSD1 Inhibition Attenuates Tumor Growth by Disrupting PLK1 Mitotic Pathway

Lysine-specific demethylase 1 (LSD1) is a histone modifier that is highly overexpressed in lung adenocarcinoma, which results in aggressive tumor biology. Tumor cell proliferation and migration analysis after LSD1 inhibition in the lung adenocarcinoma cell line PC9, using the LSD1 inhibitor HCI-2509 and siRNA, demonstrated that LSD1 activity was essential for proliferation and migration capacities of tumor cells. Moreover, reduced proliferation rates after LSD1 inhibition were shown to be associated with a cell-cycle arrest of the tumor cells in the G2-M-phase. Expression profiling followed by functional classification and pathway analysis indicated prominent repression of the polo-like kinase 1 (PLK1) pathway upon LSD1 inhibition. In contrast, transient overexpression of exogenous PLK1 plasmid rescued the LSD1 inhibition-mediated downregulation of PLK1 pathway genes. Mechanistically, LSD1 directly regulates expression of PLK1 by binding to its promoter region that subsequently affects expression of its downstream target genes. Notably, using lung adenocarcinoma TCGA datasets a significant correlation between LSD1 and PLK1 along with its downstream targets was observed. Furthermore, the LSD1/ PLK1 linkage was confirmed by IHC analysis in a clinical lung adenocarcinoma cohort (n 1/4 43). Conclusively, this is the first study showing a direct transcriptional link between LSD1 and PLK1. Implications: These findings point to a role of LSD1 in regulating PLK1 and thus efficient G2-M-transitionmediating proliferation of tumor cells and suggest targeting the LSD1/ PLK1 axis as a novel therapeutic approach for lung adenocarcinoma treatment

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

Serum levels of miRNA-34a in portal and hepatic vein before TIPS placement and its correlation with ALT-levels.

<p>(A) The levels of miRNA-34a measured in portal vein and hepatic vein before TIPS showed significant increase of miRNA-34a levels across the liver (p = 0.019). Data were shown paired and analyzed by Wilcoxon test. Of note, data of six patients lay outside of the shown range, and were not shown to increase readibility. (B) Levels of circulating miRNA-34a in the hepatic vein correlated significantly with ALT before TIPS (r_s = 0.409; p = 0.001). Data are presented using Spearman coefficient r_s and p-values. The levels of miRNA-34a were normalized to SV40 and are displayed as the x-fold of SV40.</p

Biochemical and hemodynamic parameters before TIPS insertion and at a short-term follow-up after a median of fourteen days (n = 60) compared using with Wilcoxon test.

<p>BUN, blood urea nitrogen; AST, aspartate aminotransferase; ALT, alanine aminotransferase; γGT, gamma-glutamyl transpeptidase; INR, International Normalized Ratio; PHPG, portal hepatic pressure gradient.</p