Identification of metastasis-related microRNAs in hepatocellular carcinoma

Controversies regarding and perspectives on clinical utility of biomarkers in hepatocellular carcinoma

The prevalence of hepatocellular carcinoma (HCC) worldwide parallels that of persistent infection with the hepatitis B virus (HBV) and/or hepatitis C virus (HCV). According to recommendations by the World Health Organization guidelines for HBV/HCV, alpha-fetoprotein (AFP) testing and abdominal ultrasound should be performed in routine surveillance of HCC every 6 mo for high-risk patients. These examinations have also been recommended worldwide by many other HCC guidelines over the past few decades. In recent years, however, the role of AFP in HCC surveillance and diagnosis has diminished due to advances in imaging modalities. AFP was excluded from the surveillance and/or diagnostic criteria in the HCC guidelines published by the American Association for the Study of Liver Diseases in 2010, the European Association for the Study of the Liver in 2012, and the National Comprehensive Cancer Network in 2014. Other biomarkers, including the Lens culinaris agglutinin-reactive fraction of AFP (AFP-L3), des-γ-carboxyprothrombin, Dickkopf-1, midkine, and microRNA, are being studied in this regard. Furthermore, increasing attention has focused on the clinical utility of biomarkers as pre-treatment predictors for tumor recurrence and as post-treatment monitors. Serum and tissue-based biomarkers and genomics may aid in the diagnosis of HCC, determination of patient prognosis, and selection of appropriate treatment. However, further studies are needed to better characterize the accuracy and potential role of these approaches in clinical practice.

miRNA for diagnosis and clinical implications of human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies, as a result of being asymptomatic at early stage, subsequent late clinical confirmation and poor prognosis. It is urgent to search more accurate biomarkers for diagnosing early HCC and predicting prognosis. Many factors participate in liver carcinogenesis, including dysregulation of miRNA. miRNA were endogenously expressed non-coding single-stranded small RNA with 19-25 nucleotides. Accumulating evidences have showed that miRNA from circulation and solitary tumors may be useful to classify the differentiation degree and stages of HCC, detect the hepatitis B/C virus-related HCC, and predict the survival rate after surgical resection or orthotopic liver transplantation. In this review, we summarize dysregulated miRNA, their roles in diagnosis and clinical implications of HCC.

Portal vein tumor thrombus is a bottleneck in the treatment of hepatocellular carcinoma

The effect of portal vein tumor thrombus (PVTT) on the prognosis of patients with hepatocellular carcinoma has become clear over the past several decades. However, identifying the mechanisms and performing the diagnosis and treatment of PVTT remain challenging. Therefore, this study aimed to summarize the progress in these areas. A computerized literature search in Medline and EMBASE was performed with the following combinations of search terms: “hepatocellular carcinoma” AND “portal vein tumor thrombus.” Although several signal transduction or molecular pathways related to PVTT have been identified, the exact mechanisms of PVTT are still largely unknown. Many biomarkers have been reported to detect microvascular invasion, but none have proved to be clinically useful because of their low accuracy rates. Sorafenib is the only recommended therapeutic strategy in Western countries. However, more treatment options are recommended in Eastern countries, including surgery, radiotherapy (RT), transhepatic arterial chemoembolization (TACE), transarterial radioembolization (TARE), and sorafenib. Therefore, we established a staging system based on the extent of portal vein invasion. Our staging system effectively predicts the long-term survival of PVTT patients. Currently, several clinical trials had shown that surgery is effective and safe in some PVTT patients. RT, TARE, and TACE can also be performed safely in patients with good liver function. However, only a few comparative clinical trials had compared the effectiveness of these treatments. Therefore, more randomized controlled trials examining the extent of PVTT should be conducted in the future.

Relevance of Rabbit VX2 Tumor Model for Studies on Human Hepatocellular Carcinoma: A MicroRNA-Based Study

MicroRNAs are small (~22 nt), noncoding RNA molecules that have critical cellular functions in proliferation, differentiation, angiogenesis and apoptosis. miRNA expression profiling has been used to create signatures of solid tumors and, in many cases, it has been shown to correlate with the severity of the disease. The rabbit VX2 tumor model has been used widely to study a number of human cancers. Our objective in this study is to generate an miRNA signature of the VX2 tumor and to identify miRNAs that are highly expressed in this aggressive tumor. In this study, we performed miRNA profiling of the rabbit VX2 tumor using a microarray that has probes for 1292 unique miRNAs. Their expression in tumor samples was quantified and analyzed. We found that 35 miRNAs were significantly up-regulated in the VX2 tumor. Among these, 13 human miRNAs and eight members of the let-7 family were previously identified in cancers. In addition, we show that the expression of three miRNAs (miR-923, miR-1275, and miR-1308) is novel for the rabbit VX2 tumor, and their expression was not previously shown to be associated with any type of cancer. For the first time, we show the miRNA signature profile for a solid tumor in a rabbit model. miRNAs highly expressed in the VX2 tumor may serve as novel candidates for molecular biomarkers and as potential drug targets.

H2.0-like homeobox 1 acts as a tumor suppressor in hepatocellular carcinoma

H2.0-like homeobox 1 (HLX1) is a homeobox transcription factor gene expressed primarily in cytotrophoblast cell types in the early pregnancy human placenta and involved in the development of enteric nervous system. However, the biological function of HLX1 in hepatocellular carcinoma (HCC) remains unclear. In the present study, semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), quantitative real-time RT-PCR, western blot, and immunohistochemical staining were used to examine the expression level of HLX1 in a total of 125 cases of HCC tissues and their matched adjacent nontumorous tissues (ANLTs), and its correlation with clinical features of HCC patients was analyzed. Our findings showed that the expression level of HLX1 was significantly reduced in HCCs compared to ANLTs. Besides, it was also remarkably downregulated in HCC cell lines compared to normal liver cell line. We further found that the HLX1 level was significantly associated with the tumor size (p = 0.016), tumor number (p = 0.004), vascular invasion (p = 0.031), Edmondson-Steiner grade (p = 0.041), tumor-node-metastasis (TNM) stage (p < 0.001), and Barcelona clinic liver cancer (BCLC) stage (p = 0.008). Moreover, HLX1 was an independent risk factor for overall survival (OS, p = 0.020) and disease-free survival (DFS, p = 0.024) of HCC patients. In vitro experiments showed that overexpression of HLX1 markedly suppressed the invasion, migration, proliferation, and colony formation of HCC cells; in contrast, downregulation of HLX1 significantly promoted the invasion, migration, proliferation, and colony formation of HCC cells. In vivo study indicated that overexpression of HLX1 significantly inhibited the tumorigenic capacity of HCC cells in nude mice. Based on these findings, we suggest that HLX1 acts as a tumor suppressor in HCC.

DNA methylation mediated silencing of microRNA-145 is a potential prognostic marker in patients with lung adenocarcinoma

The molecular mechanism of down-regulated microRNA-145 (miR-145) expression in lung adenocarcinoma (LAC) remains largely unknown. We hypothesized that aberrant hyper-methylation of the CpG sites silenced the expression of miR-145 in LAC. In consideration of its pivotal role in LAC development and progression, we also evaluated the clinical utility of miR-145 as a prognostic marker. We assessed the DNA methylation status of the miR-145 promoter region in 20 pairs of LAC and the matched non-tumor specimens. We subsequently applied our own LAC tissue microarray containing 92 pairs of tumor and non-tumor tissues with long time follow-up records to evaluate whether miR-145 is a potential prognostic marker in LAC. The Sequenom EpiTYPER MassArray analysis showed that miR-145 was down-regulated in human LAC tissues accompanied by increased DNA methylation of its upstream region, which was further validated by the data from TCGA database. Significance was observed between miR-145 expression and clinic-pathologic parameters. Univariate and multivariate analysis revealed that miR-145 expression level was an independent risk factor for both OS and DFS in LAC patients. Taken together, DNA hyper-methylation in the miR-145 promoter region reduced its expression in LAC and miR-145 expression level might serve as a novel prognostic biomarker.

Clinicopathological Significance of MicroRNA-20b Expression in Hepatocellular Carcinoma and Regulation of HIF-1α and VEGF Effect on Cell Biological Behaviour

miRNA-20b has been shown to be aberrantly expressed in several tumor types. However, the clinical significance of miRNA-20b in the prognosis of patients with hepatocellular carcinoma (HCC) is poorly understood, and the exact role of miRNA-20b in HCC remains unclear. The aim of the present study was to investigate the association of the expression of miR-20b with clinicopathological characteristics and overall survival of HCC patients analyzed by Kaplan-Meier analysis and Cox proportional hazards regression models. Meanwhile, the HIF-1α and VEGF targets of miR-20b have been confirmed. We found not only miR-20b regulation of HIF-1α and VEGF in normal but also regulation of miR-20b in hypoxia. This mechanism would help the tumor cells adapt to the different environments thus promoting the tumor invasion and development. The whole study suggests that miR-20b, HIF-1α, and VEGF serve as a potential therapeutic agent for hepatocellular carcinoma.

New Tools for Molecular Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common type of liver cancer, arising from neoplastic transformation of hepatocytes or liver precursor/stem cells. HCC is often associated with pre-existing chronic liver pathologies of different origin (mainly subsequent to HBV and HCV infections), such as fibrosis or cirrhosis. Current therapies are essentially still ineffective, due both to the tumor heterogeneity and the frequent late diagnosis, making necessary the creation of new therapeutic strategies to inhibit tumor onset and progression and improve the survival of patients. A promising strategy for treatment of HCC is the targeted molecular therapy based on the restoration of tumor suppressor proteins lost during neoplastic transformation. In particular, the delivery of master genes of epithelial/hepatocyte differentiation, able to trigger an extensive reprogramming of gene expression, could allow the induction of an efficient antitumor response through the simultaneous adjustment of multiple genetic/epigenetic alterations contributing to tumor development. Here, we report recent literature data supporting the use of members of the liver enriched transcription factor (LETF) family, in particular HNF4α, as tools for gene therapy of HCC.

MicroRNA panels as disease biomarkers distinguishing hepatitis B virus infection caused hepatitis and liver cirrhosis

An important unresolved clinical issue is to distinguish hepatitis B virus (HBV) infection caused chronic hepatitis and their corresponding liver cirrhosis (LC). Recent research suggests that circulating microRNAs are useful biomarkers for a wide array of diseases. We analyzed microRNA profiles in the plasmas of a total of 495 chronic hepatitis B (CHB) patients, LC patients and healthy donors and identified 10 miRNAs that were differentially expressed between CHB and LC patients. Our logistic models show that three panels of miRNAs have promising diagnostic performances in discriminating CHB from LC. Blinded tests were subsequently conducted to evaluate the diagnostic performances in clinical practice and a sensitivity of 85% and specificity of 70% have been achieved in separating CHB from LC pateints. The expression levels of some circulating miRNAs were significantly correlated with HBV DNA load and liver function, such as prothrombin activity (PTA) and levels of alanin aminotransferase (ALT), albumin (ALB) and cholinesterase (CHE). Our results provide important information for developing novel diagnostic tools for distinguishing chronic HBV hepatitis and their corresponding cirrhosis.

Genetic Landscape and Biomarkers of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has emerged as a major cause of cancer-related death. Its mortality has increased in Western populations, with a minority of patients diagnosed at early stages, when curative treatments are feasible. Only the multikinase inhibitor sorafenib is available for the management of advanced cases. During the last 10 years, there has been a clear delineation of the landscape of genetic alterations in HCC, including high-level DNA amplifications in chromosome 6p21 (VEGFA) and 11q13 (FGF19/CNND1), as well as homozygous deletions in chromosome 9 (CDKN2A). The most frequent mutations affect TERT promoter (60%), associated with an increased telomerase expression. TERT promoter can also be affected by copy number variations and hepatitis B DNA insertions, and it can be found mutated in preneoplastic lesions. TP53 and CTNNB1 are the next most prevalent mutations, affecting 25%-30% of HCC patients, that, in addition to low-frequency mutated genes (eg, AXIN1, ARID2, ARID1A, TSC1/TSC2, RPS6KA3, KEAP1, MLL2), help define some of the core deregulated pathways in HCC. Conceptually, some of these changes behave as prototypic oncogenic addiction loops, being ideal biomarkers for specific therapeutic approaches. Data from genomic profiling enabled a proposal of HCC in 2 major molecular clusters (proliferation and nonproliferation), with differential enrichment in prognostic signatures, pathway activation and tumor phenotype. Translation of these discoveries into specific therapeutic decisions is an unmet medical need in this field.

MiR-199a-5p is negatively associated with malignancies and regulates glycolysis and lactate production by targeting hexokinase 2 in liver cancer

Cancer cells possess a unique metabolic phenotype that allows them to preferentially utilize glucose through aerobic glycolysis. This phenomenon is referred to as the "Warburg effect." Accumulating evidence suggests that microRNAs (miRNAs), a class of small noncoding regulatory RNAs, interact with oncogenes/tumor suppressors and induce such metabolic reprograming in cancer cells. To systematically study the metabolic roles of miRNAs in cancer cells, we developed a gain-of-function miRNA screen in HeLa cells. Subsequent investigation of the characterized miRNAs indicated that miR-199a-5p acts as a suppressor for glucose metabolism. Furthermore, miR-199a-5p is often down-regulated in human liver cancer, and its low expression level was correlated with a low survival rate, large tumor size, poor tumor differentiation status, high tumor-node-metastasis stage and the presence of tumor thrombus of patients. MicroRNA-199a-5p directly targets the 3'-untranslated region of hexokinase 2 (HK2), an enzyme that catalyzes the irreversible first step of glycolysis, thereby suppressing glucose consumption, lactate production, cellular glucose-6-phosphate and adenosine triphosphate levels, cell proliferation, and tumorigenesis of liver cancer cells. Moreover, HK2 is frequently up-regulated in liver cancer tissues and associated with poor patient outcomes. The up-regulation of hypoxia-inducible factor-1α under hypoxic conditions suppresses the expression of miR-199a-5p and promotes glycolysis, whereas reintroduction of miR-199a-5p interferes with the expression of HK2, abrogating hypoxia-enhanced glycolysis.

CONCLUSION

miR-199a-5p/HK2 reprograms the metabolic process in liver cancer cells and provides potential prognostic predictors for liver cancer patients.

A Surgical Perspective on Targeted Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the second leading cause of cancer deaths worldwide, is difficult to treat and highly lethal. Since HCC is predominantly diagnosed in patients with cirrhosis, treatment planning must consider both the severity of liver disease and tumor burden. To minimize the impact to the patient while treating the tumor, techniques have been developed to target HCC. Anatomical targeting by surgical resection or locoregional therapies is generally reserved for patients with preserved liver function and minimal to moderate tumor burden. Patients with decompensated cirrhosis and small tumors are optimal candidates for liver transplantation, which offers the best chance of long-term survival. Yet, only 20%-30% of patients have disease amenable to anatomical targeting. For the majority of patients with advanced HCC, chemotherapy is used to target the tumor biology. Despite these treatment options, the five-year survival of patients in the United States with HCC is only 16%. In this review we provide a comprehensive overview of current approaches to target HCC. We also discuss emerging diagnostic and prognostic biomarkers, novel therapeutic targets identified by recent genomic profiling studies, and potential applications of immunotherapy in the treatment of HCC.

Hepatocellular carcinoma associated microRNA expression signature: integrated bioinformatics analysis, experimental validation and clinical significance

microRNA (miRNA) expression profiles varied greatly among current studies due to different technological platforms and small sample size. Systematic and integrative analysis of published datesets that compared the miRNA expression profiles between hepatocellular carcinoma (HCC) tissue and paired adjacent noncancerous liver tissue was performed to determine candidate HCC associated miRNAs. Moreover, we further validated the confirmed miRNAs in a clinical setting using qRT-PCR and Tumor Cancer Genome Atlas (TCGA) dataset. A miRNA integrated-signature of 5 upregulated and 8 downregulated miRNAs was identified from 26 published datesets in HCC using robust rank aggregation method. qRT-PCR demonstrated that miR-93-5p, miR-224-5p, miR-221-3p and miR-21-5p was increased, whereas the expression of miR-214-3p, miR-199a-3p, miR-195-5p, miR-150-5p and miR-145-5p was decreased in the HCC tissues, which was also validated on TCGA dataset. A miRNA based score using LASSO regression model provided a high accuracy for identifying HCC tissue (AUC = 0.982): HCC risk score = 0.180E_miR-221 + 0.0262E_miR-21 - 0.007E_miR-223 - 0.185E_miR-130a. E_miR-n = Log 2 (expression of microRNA n). Furthermore, expression of 5 miRNAs (miR-222, miR-221, miR-21 miR-214 and miR-130a) correlated with pathological tumor grade. Cox regression analysis showed that miR-21 was related with 3-year survival (hazard ratio [HR]: 1.509, 95%CI: 1.079-2.112, P = 0.016) and 5-year survival (HR: 1.416, 95%CI: 1.057-1.897, P = 0.020). However, none of the deregulated miRNAs was related with microscopic vascular invasion. This study provides a basis for further clinical application of miRNAs in HCC.

Low-level expression of microRNA-375 predicts poor prognosis in hepatocellular carcinoma

MicroRNAs are predicted to play fundamental roles in the tumorigenesis of hepatocellular carcinoma (HCC). MiR-375 is frequently downregulated in HCC and acts as a tumor suppressor by targeting multiple oncogenes. The objective of this study was to evaluate miR-375 expression and its relevance to the prognosis of HCC. MiR-375 expression was measured in cancerous tissues using qRT-PCR and dichotomized based on a median cutoff. The association between miR-375 expression and clinicopathological parameters and prognosis was subsequently determined. Expression levels of miR-375 were detected in a cohort of 38 HCC patients who underwent curative surgery. No significant correlations were observed between miR-375 expression and clinicopathological parameters, such as gender, age, performance status, preoperative serum AFP level, histological grade, HBV-DNA copy number, ascites, cirrhosis, tumor size, number of tumor nodules, and macrovascular invasion. However, miR-375 expression differs across CLIP scores significantly (p < 0.05). A trend toward poorer disease-free survival (DFS) was observed in patients with lower miR-375 expression compared to those with higher miR-375 expression (p = 0.307). Multivariate analysis demonstrated that low miR-375 expression was an independent prognostic predictor for progression (p = 0.032, risk ratio 3.273). Subgroup analysis revealed that low expression of miR-375 was significantly associated with adverse DFS in patients with poorly differentiated histology, higher serum AFP level (≥400 ng/ml), and advanced tumor stage (CLIP score 1∼3) (p = 0.017, 0.009, and 0.024, respectively). Our study demonstrates that miR-375 expression is significantly correlated with DFS and may be a potential prognostic biomarker of disease progression in HCC.

Identification of microRNAs specific for epithelial cell adhesion molecule-positive tumor cells in hepatocellular carcinoma

Therapies that target cancer stem cells (CSCs) hold promise in eliminating cancer burden. However, normal stem cells are likely to be targeted owing to their similarities to CSCs. It is established that epithelial cell adhesion molecule (EpCAM) is a biomarker for normal hepatic stem cells (HpSCs), and EpCAM(+) AFP(+) hepatocellular carcinoma (HCC) cells have enriched hepatic CSCs. We sought to determine whether specific microRNAs (miRNAs) exist in hepatic CSCs that are not expressed in normal HpSCs. We performed a pair-wise comparison of the miRNA transcriptome of EpCAM(+) and corresponding EpCAM(-) cells isolated from two primary HCC specimens, as well as from two fetal livers and three healthy adult liver donors by small RNA deep sequencing. We found that miR-150, miR-155, and miR-223 were preferentially highly expressed in EpCAM(+) HCC cells, which was further validated. Their gene surrogates, identified using miRNA and messenger RNA profiling in a cohort of 292 HCC patients, were associated with patient prognosis. We further demonstrated that miR-155 was highly expressed in EpCAM(+) HCC cells, compared to corresponding EpCAM(-) HCC cells, fetal livers with enriched normal hepatic progenitors, and normal adult livers with enriched mature hepatocytes. Suppressing miR-155 resulted in a decreased EpCAM(+) fraction in HCC cells and reduced HCC cell colony formation, migration, and invasion in vitro. The reduced levels of identified miR-155 targets predicted the shortened overall survival and time to recurrence of HCC patients.

CONCLUSION

miR-155 is highly elevated in EpCAM(+) HCC cells and might serve as a molecular target to eradicate the EpCAM(+) CSC population in human HCCs.

MicroRNAs: Emerging Novel Clinical Biomarkers for Hepatocellular Carcinomas

The discovery of small non-coding RNAs known as microRNAs has refined our view of the complexity of gene expression regulation. In hepatocellular carcinoma (HCC), the fifth most frequent cancer and the third leading cause of cancer death worldwide, dysregulation of microRNAs has been implicated in all aspects of hepatocarcinogenesis. In addition, alterations of microRNA expression have also been reported in non-cancerous liver diseases including chronic hepatitis and liver cirrhosis. MicroRNAs have been proposed as clinically useful diagnostic biomarkers to differentiate HCC from different liver pathologies and healthy controls. Unique patterns of microRNA expression have also been implicated as biomarkers for prognosis as well as to predict and monitor therapeutic responses in HCC. Since dysregulation has been detected in various specimens including primary liver cancer tissues, serum, plasma, and urine, microRNAs represent novel non-invasive markers for HCC screening and predicting therapeutic responses. However, despite a significant number of studies, a consensus on which microRNA panels, sample types, and methodologies for microRNA expression analysis have to be used has not yet been established. This review focuses on potential values, benefits, and limitations of microRNAs as new clinical markers for diagnosis, prognosis, prediction, and therapeutic monitoring in HCC.

NF-κB signaling relieves negative regulation by miR-194 in hepatocellular carcinoma by suppressing the transcription factor HNF-1α

Constitutive activation of the proinflammatory transcription factor nuclear factor κB (NF-κB) plays an important role in progression of hepatocellular carcinoma (HCC). Emerging modulators of NF-κB signaling are noncoding RNAs, especially microRNAs (miRNAs). We previously identified miRNAs that reduced the induction of NF-κB activity upon addition of tumor necrosis factor-α (TNFα) to HCC cells. We found that among these miRNAs, the abundance of liver-enriched miR-194 was decreased in HCC tissue and that low abundance of miR-194 correlated with a high occurrence of vascular invasion. Overexpressing miR-194 suppressed HCC cell migration and invasiveness in culture and metastatic seeding in mice. Transcripts encoding tripartite motif containing 23 (TRIM23), a ubiquitin ligase involved in NF-κB activation, and chromosome 21 open reading frame 91 (C21ORF91), a protein of unknown function, were identified as direct targets of miR-194 in HCC cells; knocking down either protein decreased the activity of a luciferase NF-κB reporter. Furthermore, the NF-κB pathway activator TNFα, an inflammatory cytokine, inhibited the transcription of miR-194 by decreasing the abundance of hepatocyte nuclear factor-1α (HNF-1α). The abundance of miR-194 positively correlated with that of HNF-1α and inversely correlated with that of TNFα in human HCC tissue. Thus, we identified a pathway in which TNFα-NF-κB signaling switches off negative regulation by suppressing HNF-1α-mediated expression of miR-194, revealing insight into the mechanisms linking inflammatory pathways, miRNA, and HCC metastasis.

Current issues on genomic heterogeneity in hepatocellular carcinoma and its implication in clinical practice

Hepatocellular carcinoma (HCC) is a highly heterogeneous disease leading to a major diversity. Since staging systems are used in patient care, molecular and histopathological features remain to be incorporated in management algorithms. HCC, as other malignant solid tumors, exhibit a complex genetic diversity and genomic instability, driving tumorigenesis. The recent development of deep sequencing techniques has revealed different subgroups of tumors defined by specific patterns of genomic alterations that are related to clinical and histopathological diversity in HCC. Additionally, several genomic defects identified in HCC will be used in the future to develop clinical trial design for tumorized treatment.

Translational progress on tumor biomarkers

There is an urgent need to apply basic research achievements to the clinic. In particular, mechanistic studies should be developed by bench researchers, depending upon clinical demands, in order to improve the survival and quality of life of cancer patients. To date, translational medicine has been addressed in cancer biology, particularly in the identification and characterization of novel tumor biomarkers. This review focuses on the recent achievements and clinical application prospects in tumor biomarkers based on translational medicine.

Functional microRNA high throughput screening reveals miR-9 as a central regulator of liver oncogenesis by affecting the PPARA-CDH1 pathway

Background

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths, reflecting the aggressiveness of this type of cancer and the absence of effective therapeutic regimens. MicroRNAs have been involved in the pathogenesis of different types of cancers, including liver cancer. Our aim was to identify microRNAs that have both functional and clinical relevance in HCC and examine their downstream signaling effectors.

Methods

MicroRNA and gene expression levels were measured by quantitative real-time PCR in HCC tumors and controls. A TargetScan algorithm was used to identify miR-9 downstream direct targets.

Results

A high-throughput screen of the human microRNAome revealed 28 microRNAs as regulators of liver cancer cell invasiveness. MiR-9, miR-21 and miR-224 were the top inducers of HCC invasiveness and also their expression was increased in HCC relative to control liver tissues. Integration of the microRNA screen and expression data revealed miR-9 as the top microRNA, having both functional and clinical significance. MiR-9 levels correlated with HCC tumor stage and miR-9 overexpression induced SNU-449 and HepG2 cell growth, invasiveness and their ability to form colonies in soft agar. Bioinformatics and 3′UTR luciferase analyses identified E-cadherin (CDH1) and peroxisome proliferator-activated receptor alpha (PPARA) as direct downstream effectors of miR-9 activity. Inhibition of PPARA suppressed CDH1 mRNA levels, suggesting that miR-9 regulates CDH1 expression directly through binding in its 3′UTR and indirectly through PPARA. On the other hand, miR-9 inhibition of overexpression suppressed HCC tumorigenicity and invasiveness. PPARA and CDH1 mRNA levels were decreased in HCC relative to controls and were inversely correlated with miR-9 levels.

Conclusions

Taken together, this study revealed the involvement of the miR-9/PPARA/CDH1 signaling pathway in HCC oncogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1562-9) contains supplementary material, which is available to authorized users.

MiR-324-5p Suppresses Hepatocellular Carcinoma Cell Invasion by Counteracting ECM Degradation through Post-Transcriptionally Downregulating ETS1 and SP1

Hepatocellular carcinoma (HCC) is one of the common malignancies, which is highly metastatic and the third common cause of cancer deaths in the world. The invasion and metastasis of cancer cells is a multistep and complex process which is mainly initiated by extracellular matrix (ECM) degradation. Aberrant expression of microRNA has been investigated in HCC and shown to play essential roles during HCC progression. In the present study, we found that microRNA-324-5p (miR-324-5p) was downregulated in both HCC cell lines and tissues. Ectopic miR-324-5p led to the reduction of HCC cells invasive and metastatic capacity, whereas inhibition of miR-324-5p promoted the invasion of HCC cells. Matrix metalloproteinase 2 (MMP2) and MMP9, the major regulators of ECM degradation, were found to be downregulated by ectopic miR-324-5p, while upregulated by miR-324-5p inhibitor. E26 transformation-specific 1 (ETS1) and Specificity protein 1 (SP1), both of which could modulate MMP2 and MMP9 expression and activity, were presented as the direct targets of and downregulated by miR-324-5p. Downregulation of ETS1 and SP1 mediated the inhibitory function of miR-324-5p on HCC migration and invasion. Our study demonstrates that miR-324-5p suppresses hepatocellular carcinoma cell invasion and might provide new clues to invasive HCC therapy.

Guide for diagnosis and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is ranked as the 5^th common type of cancer worldwide and is considered as the 3^rd common reason for cancer-related deaths. HCC often occurs on top of a cirrhotic liver. The prognosis is determined by several factors; tumour extension, alpha-fetoprotein (AFP) concentration, histologic subtype of the tumour, degree of liver dysfunction, and the patient’s performance status. HCC prognosis is strongly correlated with diagnostic delay. To date, no ideal screening modality has been developed. Analysis of recent studies showed that AFP assessment lacks adequate sensitivity and specificity for effective surveillance and diagnosis. Many tumour markers have been tested in clinical trials without progressing to routine use in clinical practice. Thus, surveillance is still based on ultrasound (US) examination every 6 mo. Imaging studies for diagnosis of HCC can fall into one of two main categories: routine non-invasive studies such as US, computed tomography (CT), and magnetic resonance imaging, and more specialized invasive techniques including CT during hepatic arteriography and CT arterial portography in addition to the conventional hepatic angiography. This article provides an overview and spotlight on the different diagnostic modalities and treatment options of HCC.

Increased miR-16 expression induced by hepatitis C virus infection promotes liver fibrosis through downregulation of hepatocyte growth factor and Smad7

Hepatitis C virus (HCV) is involved in the initiation and progression of liver fibrosis by regulating genes encoding host proteins. However, the underlying mechanism of HCV-induced liver fibrosis is still to be determined. Reverse transcription polymerase chain reaction (RT-PCR) and western blot were performed to investigate the effect of HCV infection on the expression of the cellular microRNA miR-16 and its target genes encoding hepatocyte growth factor (HGF) and Smad7 in patients infected with HCV and in a liver cell line, QSG-7701, transfected with Ad-HCV, a recombinant adenovirus construct for expression of the HCV core protein. Regulation of HGF and Smad7 expression by miR-16 was assessed using luciferase reporter construct assays and miR-16 mimic transfection. Interferon-α (IFN-α) was used to verify the alteration of gene expression induced by HCV in QSG-7701 cells. Here, we found that miR-16 levels were increased in patients with HCV infection and were correlated with HGF and Smad7 expression levels in patients with HCV infection. Furthermore, HGF and Smad7 were predicted by bioinformatics analysis to be targets of miR-16. Upregulation of miR-16 and decreased HGF and Smad7 expression were still shown in QSG-7701 cells infected with Ad-HCV. Additionally, interferon-α (IFN-α) could reverse the changes in gene expression induced by HCV infection. These results suggest that the upregulation of miR-16 expression induced by HCV infection is a novel mechanism that contributes to downregulation of HGF and Smad7 in the development of liver fibrosis.

A Seven-microRNA Expression Signature Predicts Survival in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth common cancer. The differential expression of microRNAs (miRNAs) has been associated with the prognosis of various cancers. However, limited information is available regarding genome-wide miRNA expression profiles in HCC to generate a tumor-specific miRNA signature of prognostic values. In this study, the miRNA profiles in 327 HCC patients, including 327 tumor and 43 adjacent non-tumor tissues, from The Cancer Genome Atlas (TCGA) Liver hepatocellular carcinoma (LIHC) were analyzed. The associations of the differentially expressed miRNAs with patient survival and other clinical characteristics were examined with t-test and Cox proportional regression model. Finally, a tumor-specific miRNA signature was generated and examined with Kaplan-Meier survival, univariate\multivariate Cox regression analyses and KEGG pathway analysis. Results showed that a total of 207 miRNAs were found differentially expressed between tumor and adjacent non-tumor HCC tissues. 78 of them were also discriminatively expressed with gender, race, tumor grade and AJCC tumor stage. Seven miRNAs were significantly associated with survival (P value <0.001). Among the seven significant miRNAs, six (hsa-mir-326, hsa-mir-3677, hsa-mir-511-1, hsa-mir-511-2, hsa-mir-9-1, and hsa-mir-9-2) were negatively associated with overall survival (OS), while the remaining one (hsa-mir-30d) was positively correlated. A tumor-specific 7-miRNAs signature was generated and validated as an independent prognostic predictor. Collectively, we have identified and validated an independent prognostic model based on the expression of seven miRNAs, which can be used to assess patients' survival. Additional work is needed to translate our model into clinical practice.

Non-Coding RNAs in Primary Liver Cancer

Hepatocellular carcinoma (HCC) is a primary malignancy of the liver with poor prognosis and limited therapeutic options. Over the past few years, many studies have evaluated the role of non-coding RNAs (ncRNAs) in hepatocarcinogenesis and tumor progression. ncRNAs were shown to have diagnostic, prognostic, and therapeutic potential in HCC. In this manuscript, we review the latest major discoveries concerning microRNAs and long ncRNAs in HCC pathogenesis, and discuss the potentials and the limitations for their use in clinical practice.

miR-744 is a potential prognostic marker in patients with hepatocellular carcinoma

Identification of new biomarkers for aggressiveness of hepatocellular carcinoma (HCC) to supplement the current group of prognosis algorithms is a significant clinical need. To clarify expression levels of microRNA-744 (miR-744) in HCC tissues and to explore its clinicopathological significance in HCC patients following liver transplantation (LT), we quantified miR-744 using real-time quantitative reverse transcription polymerase chain reaction in 96 paired cancerous tissues and para-cancerous normal liver tissues. We investigated relationships among miR-744 expression, clinicopathological parameters, and overall survival (OS). Of 96 paired samples, 68 cancer tissues expressed low miR-744 compared with their matched normal liver tissues. Patients with microvascular invasion or multi-tumor nodules showed significantly lower miR-744 expression; miR-744 was further decreased in patients with post-LT HCC recurrence compared with non-recurring patients. Patients with lower miR-744 expression showed significantly poorer recurrence-free survival and OS than individuals with higher miR-744 levels. Multivariate analysis revealed that lower miR-744 was an independent predictor of poor prognosis. Our results associate decreased miR-744 expression with HCC recurrence and prognosis, and also suggest that miR-744 is an independent predictor of survival in HCC patients after LT and may therefore be a potential biomarker for their prognosis.

A null model for Pearson coexpression networks

Gene coexpression networks inferred by correlation from high-throughput profiling such as microarray data represent simple but effective structures for discovering and interpreting linear gene relationships. In recent years, several approaches have been proposed to tackle the problem of deciding when the resulting correlation values are statistically significant. This is most crucial when the number of samples is small, yielding a non-negligible chance that even high correlation values are due to random effects. Here we introduce a novel hard thresholding solution based on the assumption that a coexpression network inferred by randomly generated data is expected to be empty. The threshold is theoretically derived by means of an analytic approach and, as a deterministic independent null model, it depends only on the dimensions of the starting data matrix, with assumptions on the skewness of the data distribution compatible with the structure of gene expression levels data. We show, on synthetic and array datasets, that the proposed threshold is effective in eliminating all false positive links, with an offsetting cost in terms of false negative detected edges.

Blockage of TGFβ-SMAD2 by demethylation-activated miR-148a is involved in caffeic acid-induced inhibition of cancer stem cell-like properties in vitro and in vivo

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Caffeic acid (CaA) attenuates CSCs-like properties in human cancer cells.

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CaA inhibits the activity/expression of SMAD2.

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CaA elevates the expression of miR-148a by inducing DNA demethylation.

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miR-148a targets SMAD2 in CaA-treated cells.

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CaA attenuates CSCs-like properties via miR-148a.

Current standard practices for treatment of cancers are less than satisfactory because of recurrence mediated by cancer stem cells (CSCs). Caffeic acid (CaA) is a novel anti-tumor agent that inhibits proliferation, migration, and invasion in human cancer cells. However, little is known about the functions of CaA in regulating CSCs-like properties and the potential molecular mechanisms. Here, we found that CaA attenuated the CSCs-like properties by the microRNA-148a (miR-148a)-mediated inhibition of transforming growth factor beta (TGFβ)-SMAD2 signaling pathway both in vitro and in vivo. CaA enhanced the expression of miR-148a by inducing DNA methylation. MiR-148a, which targeted the SMAD2-3′UTR, decreased the expression of SMAD2. Knockdown of miR-148a abolished the CaA-induced inhibition of TGFβ-SMAD2 signal pathway and the CSCs-like properties. Our study found a novel mechanism that CaA inhibits the CSCs-like properties via miR-148a-mediated inhibition of TGFβ-SMAD2 signaling pathway, which may help to identify a new approach for the treatment of human cancers.

Hepatocellular carcinoma: Advances in diagnosis, management, and long term outcome

Hepatocellular carcinoma (HCC) remains a common and lethal malignancy worldwide and arises in the setting of a host of diseases. The incidence continues to increase despite multiple vaccines and therapies for viruses such as the hepatitis B and C viruses. In addition, due to the growing incidence of obesity in Western society, there is anticipation that there will be a growing population with HCC due to non-alcoholic fatty liver disease. Due to the growing frequency of this disease, screening is recommended using ultrasound with further imaging using magnetic resonance imaging and multi-detector computed tomography used for further characterization of masses. Great advances have been made to help with the early diagnosis of small lesions leading to potential curative resection or transplantation. Resection and transplantation maybe used in a variety of patients that are carefully selected based on underlying liver disease. Using certain guidelines and clinical acumen patients may have good outcomes with either resection or transplantation however many patients are inoperable at time of presentation. Fortunately, the use of new locoregional therapies has made down staging patients a potential option making them potential surgical candidates. Despite a growing population with HCC, new advances in viral therapies, chemotherapeutics, and an expanding population of surgical and transplant candidates might all contribute to improved long-term survival of these patients.

miR-139-5p inhibits epithelial-mesenchymal transition, migration and invasion of hepatocellular carcinoma cells by targeting ZEB1 and ZEB2

Hepatocellular carcinoma (HCC) is the third most common cause of cancer deaths worldwide. miRNAs have been suggested to have important roles in HCC development. The purpose of this study was to determine the role of miR-139-5p in regulation of epithelial-mesenchymal transition (EMT) and metastasis of HCC cells. Expression levels of miR-139-5p in 49 HCC specimens with adjacent tissues and five HCC cell lines were assessed by quantitative RT-PCR. We found that miR-139-5p was down-regulated in 89.7% of the HCC tissue samples and all of the HCC cell lines. In addition, luciferase reporter assays validated direct binding of miR-139-5p to the 3' untranslated region of zinc finger E-box binding homeobox 1 (ZEB1) and ZEB2. Ectopic expression of miR-139-5p suppressed and miR-139-in promoted EMT, migration, and invasion in Hep3B and SMMC7721 cells. Furthermore, over-expression of ZEB1 and ZEB2 ablated the inhibitory effects of miR-139-5p on migration and invasion in HCC cells. Our study indicates that miR-139-5p functions as a suppressor of HCC EMT and metastasis by targeting ZEB1 and ZEB2, and it may be a therapeutic target for metastatic HCC.

MiR-940 inhibits hepatocellular carcinoma growth and correlates with prognosis of hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is among the leading causes of cancer-related death in China. Deregulation of microRNA (miRNA) contributes to HCC development by influencing cell growth, apoptosis, migration or invasion. It has been proved that miR-940 plays important roles in various cancers. Here we investigated the role of miR-940 in HCC. We found that miR-940 was remarkably decreased in HCC tissues and cell lines. Importantly, lower miR-940 expression in HCC tissues significantly correlated with the reduced patient's survival rate. Overexpression of miR-940 inhibited HCC cell line growth and induced cell apoptosis, and vice versa. Estrogen-related receptor gamma (ESRRG) was targeted by miR-940, and suppression of ESRRG inhibited HCC cell lines growth and induced cell apoptosis. In conclusion, we found that a lower level of miR-940 in HCC promoted cellular proliferation via ESRRG, which may lead to the short survival period of HCC patients.

Developing a prognostic micro-RNA signature for human cervical carcinoma

Cervical cancer remains the third most frequently diagnosed and fourth leading cause of cancer death in women worldwide. We sought to develop a micro-RNA signature that was prognostic for disease-free survival, which could potentially allow tailoring of treatment for cervical cancer patients. A candidate prognostic 9-micro-RNA signature set was identified in the training set of 79 frozen specimens. However, three different approaches to validate this signature in an independent cohort of 87 patients with formalin-fixed paraffin-embedded (FFPE) specimens, were unsuccessful. There are several challenges and considerations associated with developing a prognostic micro-RNA signature for cervical cancer, namely: tumour heterogeneity, lack of concordance between frozen and FFPE specimens, and platform selection for global micro-RNA expression profiling in this disease. Our observations provide an important cautionary tale for future miRNA signature studies for cervical cancer, which can also be potentially applicable to miRNA profiling studies involving other types of human malignancies.

Evolutionary Pattern and Regulation Analysis to Support Why Diversity Functions Existed within PPAR Gene Family Members

Peroxisome proliferators-activated receptor (PPAR) gene family members exhibit distinct patterns of distribution in tissues and differ in functions. The purpose of this study is to investigate the evolutionary impacts on diversity functions of PPAR members and the regulatory differences on gene expression patterns. 63 homology sequences of PPAR genes from 31 species were collected and analyzed. The results showed that three isolated types of PPAR gene family may emerge from twice times of gene duplication events. The conserved domains of HOLI (ligand binding domain of hormone receptors) domain and ZnF_C4 (C4 zinc finger in nuclear in hormone receptors) are essential for keeping basic roles of PPAR gene family, and the variant domains of LCRs may be responsible for their divergence in functions. The positive selection sites in HOLI domain are benefit for PPARs to evolve towards diversity functions. The evolutionary variants in the promoter regions and 3' UTR regions of PPARs result into differential transcription factors and miRNAs involved in regulating PPAR members, which may eventually affect their expressions and tissues distributions. These results indicate that gene duplication event, selection pressure on HOLI domain, and the variants on promoter and 3' UTR are essential for PPARs evolution and diversity functions acquired.

Decreased miR122 in hepatocellular carcinoma leads to chemoresistance with increased arginine

Reduced expression of microRNA122 (miR122), a liver-specific microRNA, is frequent in hepatocellular carcinoma (HCC). However, its biological significances remain poorly understood. Because deregulated amino acid levels in cancers can affect their biological behavior, we determined the amino acid levels in miR122-silenced mouse liver tissues, in which intracellular arginine levels were significantly increased. The increased intracellular arginine levels were through upregulation of the solute carrier family 7 (SLC7A1), a transporter of arginine and a direct target of miR122. Arginine is the substrate for nitric oxide (NO) synthetase, and intracellular NO levels were increased in miR122-silenced HCC cells, with increased resistance to sorafenib, a multikinase inhibitor. Conversely, maintenance of the miR122-silenced HCC cells in arginine-depleted culture media, as well as overexpression of miR122 in miR122-low-expressing HCC cells, reversed these effects and rendered the cells more sensitive to sorafenib. Using a reporter knock-in construct, chemical compounds were screened, and Wee1 kinase inhibitor was identified as upregulators of miR122 transcription, which increased the sensitivity of the cells to sorafenib. These results provide an insight into sorafenib resistance in miR122-low HCC, and suggest that arginine depletion or a combination of sorafenib with the identified compound may provide promising approaches to managing this HCC subset.

Extract of Zuojin Pill ([characters: see text]) induces apoptosis of SGC-7901 cells via mitochondria-dependent pathway

OBJECTIVE

To observe the effects of water extract of Zuojin Pill ([characters: see text], ZJP) on inhibiting the growth of human gastric cancer cell line SGC-7901 and its potential mechanism.

METHODS

Effects of ZJP on SGC-7901 cells growth were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, cell apoptosis and cell cycle were determined by flow cytometry, and apoptosis induction was detected by means of DNA gel electrophoresis. The cellular mechanism of drug-induced cell death was unraveled by assaying oxidative injury level of SGC-7901 cell, mitochondrial membrane potentials, expression of apoptosis-related genes, such as B cell lymphoma/lewkmia-2 (Bcl-2), Bcl-2 associated X protein (Bax) and cleaved caspase-3 and caspase-9.

RESULTS

ZJP exerted evident inhibitory effect on SGC-7901 cells by activating production of reactive oxygen species and elevating Bax/Bcl-2 ratio in SGC-7901 cells, leading to attenuation of mitochondrial membrane potential and DNA fragmentation.

CONCLUSIONS

ZJP inhibits the cancer cell growth via activating mitochondria-dependent apoptosis pathway. ZJP can potentially serve as an antitumor agent.

RIG-I suppresses the migration and invasion of hepatocellular carcinoma cells by regulating MMP9

The retinoic acid-induced protein I (Rig-I/Ddx58), (RIG-I) initiates a signaling cascade that induces innate immune defences which is associated with the production of type I interferons (IFNs) and inflammatory cytokines to establish an antiviral state. Aberrant RIG-I signaling leads to inflammation, autoimmune diseases and cancer. However, the role of RIG-I in hepatocellular carcinoma (HCC) is still unknown. Here, we observed that RIG-I expression was downregulated in HCC tissues and loss of RIG-I expression was correlated with poor clinicopathological features. Additionally, we demonstrated that patients with positive RIG-I expression had a better 3-year survival and RIG-I was an independent factor for predicting the prognosis of HCC patients. Elevated RIG-I expression inhibited the proliferation, migration, and invasion of HCC. Inhibiting RIG-I with its specific siRNA was able to attenuate the malignant behavior of HCC cells. Moreover, RIG-I inhibited the invasive behavior through downregulating matrix metalloproteinase-9 (MMP9). Mechanistically, RIG-I enhances IFN-α response by amplifying IFN-α effecter signaling via strengthening STAT1 activation. Addressing this pathway, we identified that RIG-I may serve as a prognostic marker and that MMP9 may be a potential target of RIG-I in HCC.

Distinct anti-oncogenic effect of various microRNAs in different mouse models of liver cancer

Deregulation of microRNAs (miRNAs) is a typical feature of human hepatocellular carcinoma (HCC). However, the in vivo relevance of miRNAs along hepatocarcinogenesis remains largely unknown. Here, we show that liver tumors induced in mice by c-Myc overexpression or AKT/Ras co-expression exhibit distinct miRNA expression profiles. Among the downregulated miRNAs, eight (miR-101, miR-107, miR-122, miR-29, miR-365, miR-375, miR-378, and miR-802) were selected and their tumor suppressor activity was determined by overexpressing each of them together with c-Myc or AKT/Ras oncogenes in mouse livers via hydrodynamic transfection. The tumor suppressor activity of these microRNAs was extremely heterogeneous in c-Myc and AKT/Ras mice: while miR-378 had no tumor suppressor activity, miR-107, mir-122, miR-29, miR-365 and miR-802 exhibited weak to moderate tumor suppressor potential. Noticeably, miR-375 showed limited antineoplastic activity against c-Myc driven tumorigenesis, whereas it strongly inhibited AKT/Ras induced hepatocarcinogenesis. Furthermore, miR-101 significantly suppressed both c-Myc and AKT/Ras liver tumor development. Altogether, the present data demonstrate that different oncogenes induce distinct miRNA patterns, whose modulation differently affects hepatocarcinogenesis depending on the driving oncogenes. Finally, our findings support a strong tumor suppressor activity of miR-101 in liver cancer models regardless of the driver oncogenes involved, thus representing a promising therapeutic target in human HCC.

MiR-520b suppresses proliferation of hepatoma cells through targeting ten-eleven translocation 1 (TET1) mRNA

Accumulating evidence indicates that microRNAs are able to act as oncogenes or tumor suppressor genes in human cancer. We previously reported that miR-520b was down-regulated in hepatocellular carcinoma (HCC) and its deregulation was involved in hepatocarcinogenesis. In the present study, we report that miR-520b suppresses cell proliferation in HCC through targeting the ten-eleven translocation 1 (TET1) mRNA. Notably, we identified that miR-520b was able to target 3'-untranslated region (3'UTR) of TET1 mRNA by luciferase reporter gene assays. Then, we revealed that miR-520b was able to reduce the expression of TET1 at the levels of mRNA and protein using reverse transcription-polymerase chain reaction and Western blotting analysis. In terms of function, 5-ethynyl-2-deoxyuridine (EdU) incorporation and colony formation assays demonstrated that the forced miR-520b expression remarkably inhibited proliferation of hepatoma cells, but TET1 overexpression could rescue the inhibition of cell proliferation mediated by miR-520b. Furthermore, anti-miR-520b enhanced proliferation of hepatoma cells, whereas silencing of TET1 abolished anti-miR-520b-induced acceleration of cell proliferation. Then, we validated that the expression levels of miR-520b were negatively related to those of TET1 mRNA in clinical HCC tissues. Thus, we conclude that miR-520b depresses proliferation of liver cancer cells through targeting 3'UTR of TET1 mRNA. Our finding provides new insights into the mechanism of hepatocarcinogenesis.

The "Macro" World of microRNAs in Hepatocellular Carcinoma

Hepatotropic viruses such as hepatitis B virus (HBV) and hepatitis C virus (HCV) are the major etiological agents associated with development of hepatocellular carcinoma (HCC). Progression of HCC is a multistep process that requires sequential or parallel deregulation of oncogenic and tumor suppressive pathways leading to chromosomal instability and neoplastic phenotype. In the recent years, microRNAs (miRNAs) have carved their own niche alongside oncogenes and tumor suppressors, owing to their innate ability to receive and relay multiple signals. Not surprisingly, miRNAs are fast emerging as central player in myriads of malignancies including HCC. miRNAs are reported to participate in initiation and progression of HCC, and have also been clinically correlated with risk assessment, disease grade, aggressiveness, and prognosis. Despite extensive data available on the role of miRNAs in HCC, there is a pressing need to integrate and evaluate these datasets to find its correlation, if any, with causal agents in order to devise novel interventional modalities. Through this review, we attempt to bridge the gap by consolidating the current knowledge and concepts in the field of HCC-related miRNAs with special emphasis on HBV and HCV. Further, we assess the potential of common as well as unique signatures that may be useful in developing novel biomarkers and therapeutics.

Wnt/β-Catenin activates MiR-183/96/182 expression in hepatocellular carcinoma that promotes cell invasion

Nearly 50% of known miRNAs are found in clusters and transcribed as polycistronic transcripts. In this study, we showed that over-expression of miR-183/96/182 cluster is frequent in hepatocellular carcinoma (HCC), a highly aggressive malignancy that is commonly fatal. In a cohort of HCC patients (n = 81), miR-183/96/182 up-regulation correlated with metastatic features including presence of microvascular invasion, advanced tumor differentiation, and shorter recurrence-free survival. Univariate and multivariate analyses further showed miR-183/96/182 over-expression represented an independent prognostic factor (Relative Risk: 2.0471; P = 0.0289). Functional investigation using siRNA against miR-183/96/182 in two invasive HCC cells indicated significant inhibition on cell migration and invasion without affecting cell viability. Forkhead boxO1 (FOXO1) was further validated as a downstream target of these three miRNAs. In investigating the regulatory mechanism underlining miR-183/96/182 over-expression, a direct interaction of CTNNB1 on the promoter region was confirmed by ChIP-PCR and luciferase reporter validations. Knockdown of CTNNB1 also showed concordant down-regulations of miR-183, -96 and -182, and the re-expression of FOXO1. Our findings demonstrated that over-expression of miR-183/96/182 confers an oncogenic function in HCC cell dissemination, and could serve as an independent prognostic predictor for HCC patients.

Role of microRNA-30c targeting ADAM19 in colorectal cancer

MicroRNAs (miRNAs) are deregulated in a number of cancers including colorectal cancer. MiR-30c belongs to miR-30 family, and is involved in a variety of malignant diseases. In this study, we detected the expression of miR-30c in colon cancer cell lines and clinical colon cancer specimens. MiR-30c was shown to be dramatically down-regulated both in cell lines and cancer tissues. Additionally, miR-30c could inhibit cancer cell growth, migration and invasion in vitro. Consistently, stable over-expression of miR-30c inhibited the growth and lung metastasis of colon cancer cell xenografts in vivo. Furthermore, bioinformatics algorithm and luciferase reporter assay indicated ADAM19 as a direct target of miR-30c. Of interest, further experiments demonstrated that inhibition of ADAM19 by miR-30c partially mediated the anti-tumor effect of miR-30c. Overall, our study provides the new insight that miR-30c inhibited colon cancer cells via targeting ADAM19. Thus, miR-30c might serve as a promising therapeutic strategy for colon cancer treatment.

Genome-Wide Expression of MicroRNAs Is Regulated by DNA Methylation in Hepatocarcinogenesis

Background. Previous studies, including ours, have examined the regulation of microRNAs (miRNAs) by DNA methylation, but whether this regulation occurs at a genome-wide level in hepatocellular carcinoma (HCC) is unclear. Subjects/Methods. Using a two-phase study design, we conducted genome-wide screening for DNA methylation and miRNA expression to explore the potential role of methylation alterations in miRNAs regulation. Results. We found that expressions of 25 miRNAs were statistically significantly different between tumor and nontumor tissues and perfectly differentiated HCC tumor from nontumor. Six miRNAs were overexpressed, and 19 were repressed in tumors. Among 133 miRNAs with inverse correlations between methylation and expression, 8 miRNAs (6%) showed statistically significant differences in expression between tumor and nontumor tissues. Six miRNAs were validated in 56 additional paired HCC tissues, and significant inverse correlations were observed for miR-125b and miR-199a, which is consistent with the inactive chromatin pattern found in HepG2 cells. Conclusion. These data suggest that the expressions of miR-125b and miR-199a are dramatically regulated by DNA hypermethylation that plays a key role in hepatocarcinogenesis.

Current biomarkers for hepatocellular carcinoma: Surveillance, diagnosis and prediction of prognosis

Biomarkers for surveillance, diagnosis and prediction of prognosis in patients with hepatocellular carcinoma (HCC) are currently not ready for introduction into clinical practice because of limited sensitivity and specificity. Especially for the early detection of small HCC novel biomarkers are needed to improve the current effectiveness of screening performed by ultrasound. The use of high-throughput technologies in hepatocellular research allows to identify molecules involved in the complex pathways in hepatocarcinogenesis. Several invasive and non-invasive biomarkers have been identified already and have been evaluated in different clinical settings. Gene signatures with prognostic potential have been identified by gene expression profiling from tumor tissue. However, a single "all-in-one" biomarker that fits all-surveillance, diagnosis, prediction of prognosis-has not been found so far. The future of biomarkers most probably lies in a combination of non-invasive biomarkers, imaging and clinical parameters in a surveillance setting. Molecular profiling of tumorous and non-tumorous liver tissue may allow a prediction of prognosis for the individual patient and hopefully clear the way for individual treatment approaches. This article gives an overview on current developments in biomarker research in HCC with a focus on currently available and novel biomarkers, in particular on microRNA.

microRNA-148a dysregulation discriminates poor prognosis of hepatocellular carcinoma in association with USP4 overexpression

Hepatocellular carcinoma (HCC) is classified as a poor prognostic tumor, and becomes frequently aggressive. MicroRNAs emerge as key contributors to tumor progression. This study investigated whether miR-148a dysregulation differentiates poor prognosis of HCC, exploring new targets of miR-148a. miR-148a dysregulation discriminated not only the overall survival and recurrence free survival rates of HCC, but the microvascular invasion. In the human HCC samples, ubiquitin specific protease 4 (USP4) and sphingosine 1-phosphate receptor 1 (S1P1) were up-regulated as the new targets of miR-148a. USP4 and S1P1 were up-regulated in mesenchymal-type liver-tumor cells with miR-148a dysregulation, facilitating migration and proliferation of tumor cells. The inverse relationship between miR-148a and the identified targets was verified in a tumor xenograft model. In the analysis of human samples, the expression of USP4, but not S1P1, correlated with the decrease of miR-148a. In a heterotropic patient-derived HCC xenograft model, USP4 was also overexpressed in G1 and G2 tumors when miR-148a was dysregulated, reflecting the closer link between miR-148a and USP4 for a shift in the expansion phase of tumorgraft. In conclusion, miR-148a dysregulation affects the poor prognosis of HCC. Of the identified targets of miR-148a, USP4 overexpression may contribute to HCC progression towards more aggressive feature.

Identification of a novel microRNA signature associated with intrahepatic cholangiocarcinoma (ICC) patient prognosis

Background

The clinical significance of microRNAs (miRNAs) in intrahepatic cholangiocarcinoma (ICC) is unclear. The objective of this study is to examine the miRNA expression profiles and identify a miRNA signature for the prognosis of ICC.

Methods

Using a custom microarray containing 1,094 probes, the miRNA expression profiles of 63 human ICCs and nine normal intrahepatic bile ducts (NIBD) were assessed. The miRNA signatures were established and their clinical significances in ICC were analyzed. The expression levels of some miRNAs were verified by quantitative real-time RT-PCR (qRT-PCR).

Results

Expression profile analysis showed 158 differentially expressed miRNAs between ICC and NIBD, with 77 up-regulated and 81 down-regulated miRNAs. From the 158 differentially expressed miRNAs, a 30-miRNA signature consisting of 10 up-regulated and 20 down-regulated miRNAs in ICC was established for distinguishing ICC from NIBD with 100% accuracy. A separate 3-miRNA signature was identified for predicting prognosis in ICC. Based on the 3-miRNA signature, a formula was constructed to compute a risk score for each patient. The patients with high-risk had significantly lower overall survival and disease-free survival than those with low-risk. The expression level of these three miRNAs detected by microarray was verified by qRT-PCR. Multivariate analysis indicated that the 3-miRNA signature was an independent prognostic predictor.

Conclusions

In this study, a 30-miRNA signature for distinguishing ICC from NIBD, and a 3-miRNA signature for evaluating prognosis of ICC were established, which might be able to serve as biomarkers for prognosis of ICC. Further studies focusing on these miRNAs may shed light on the mechanisms associated with ICC pathogenesis and progression.

Regulatory MiR-148a-ACVR1/BMP circuit defines a cancer stem cell-like aggressive subtype of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third most common cancer in Asia. HCC has heterogeneous etiologic and molecular profiles and a varied response to therapeutics. The high recurrence rate and curtailed survival in this cancer are attributed to its resistance to therapy. The ultimate goal is to develop a more effective personalized therapeutic strategy for HCC, but the first step is to develop a system for classifying the disease on the basis of molecular biomarkers. To that end, we performed mRNA and microRNA (miRNA) expression profiling in 100 HCC tissues. Clustering analysis of informative genes identified two robust subtypes, which were validated by an independent dataset. The subtype characterized by a cancer stem cell-like signature was clinically aggressive and associated with poor survival. Integrated analysis of miRNA and mRNA expression in this subtype showed that miR-148a was expressed at a significantly lower level in these tumors than in the other subtype. MiR-148a has been shown to directly suppress the expression of activin A receptor type 1 (ACVR1), a key receptor in the signaling pathway of the bone morphogenetic proteins (BMPs), which regulate many stem cell markers as well as the clinically important cytokine interleukin-8 (IL-8). Increased expression of ACVR1 and its downstream genes EPCAM, CD24, CD90, and IL-8 was associated with shorter survival in a larger cohort of 227 HCC cases. Introduction of miR-148a resulted in suppressed tumor phenotypes both in vitro and in vivo.

CONCLUSION

We identified a clinically aggressive stem cell-like subtype of HCC that is characterized by an miR-148a-ACVR1-BMP-Wnt circuit. We propose that miR-148a may serve as a prognostic biomarker and therapeutic target for this subtype of HCC.