MicroRNA-122, a tumor suppressor microRNA that regulates intrahepatic metastasis of hepatocellular carcinoma

Overexpression of a disintegrin and metalloproteinase 21 is associated with motility, metastasis, and poor prognosis in hepatocellular carcinoma

Cell motility plays an important role in intrahepatic metastasis of hepatocellular carcinoma (HCC), and predicts poor prognosis in patients. The present study investigated the role of a disintegrin and metalloproteinases (ADAMs) in HCC, since these proteins are known to be associated with cell motility. We confirmed the expression of 12 ADAMs with putative metalloproteinase activity in HCC cells, and established a KYN-2 HCC cell line stably expressing short interfering RNA against ADAM21 to investigate the effect of ADAM21 deficiency on HCC cell motility and metastasis in vitro and in vivo. We also examined ADAM21 expression in a cohort of 119 HCC patients by immunohistochemistry. ADAM21 was overexpressed in KYN-2 cells, and its knockdown reduced invasion, migration, proliferation, and metastasis relative to controls. In clinical specimens, ADAM21 positivity was associated with vascular invasion, large tumor size, high histological grade, and lower overall and recurrence-free survival as compared to cases that were negative for ADAM21 expression. A multivariate analysis revealed that ADAM21 positivity was an independent risk factor for overall (P = 0.003) and recurrence-free (P = 0.001) survival. These results suggest that ADAM21 plays a role in HCC metastasis and can serve as a prognostic marker for disease progression.

Metabolic Circuit Involving Free Fatty Acids, microRNA 122, and Triglyceride Synthesis in Liver and Muscle Tissues

BACKGROUND & AIMS

Effective treatments are needed for hepatic steatosis characterized by accumulation of triglycerides in hepatocytes, which leads to hepatocellular carcinoma. MicroRNA 122 (MIR122) is expressed only in the liver, where it regulates lipid metabolism. We investigated the mechanism by which free fatty acids (FFAs) regulate MIR122 expression and the effect of MIR122 on triglyceride synthesis.

METHODS

We analyzed MIR122 promoter activity and validated its target mRNAs by transfection of Luciferase reporter plasmids into Huh7, BNL-1ME, and HEK293 cultured cell lines. We measured levels of microRNAs and mRNAs by quantitative real-time PCR analysis of RNA extracted from plasma, liver, muscle, and adipose tissues of C57BL/6 mice given the FFA-inducer CL316243. MIR122 was inhibited using an inhibitor of MIR122. Metabolic profiles of mice were determined using metabolic chambers and by histologic analyses of liver tissues. We performed RNA sequence analyses to identify metabolic pathways involving MIR122.

RESULTS

We validated human Agpat1 and Dgat1 mRNAs, involved in triglyceride synthesis, as targets of MIR122. FFAs increased MIR122 expression in livers of mice by activating the retinoic acid-related orphan receptor alpha, and induced secretion of MIR122 from liver to blood. Circulating MIR122 entered muscle and adipose tissues of mice, reducing mRNA levels of genes involved in triglyceride synthesis. Mice injected with an inhibitor of MIR122 and then given CL316243, accumulated triglycerides in liver and muscle tissues, and had reduced rates of β-oxidation. There was a positive correlation between level of FFAs and level of MIR122 in plasma samples from 6 healthy individuals, collected before and during fasting.

CONCLUSIONS

In biochemical and histologic studies of plasma, liver, muscle, and adipose tissues from mice, we found that FFAs increase hepatic expression and secretion of MIR122, which regulates energy storage vs expenditure in liver and peripheral tissues. Strategies to reduce triglyceride levels, by increasing MIR122, might be developed for treatment of metabolic syndrome.

Involvement of inflammation and its related microRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most commonly diagnosed type of cancer. The tumor inflammatory microenvironment regulates almost every step towards liver tumorigenesis and subsequent progression, and regulation of the inflammation-related signaling pathways, cytokines, chemokines and non-coding RNAs influences the proliferation, migration and metastasis of liver tumor cells. Inflammation fine-tunes the cancer microenvironment to favor epithelial-mesenchymal transition, in which cancer stem cells maintain tumorigenic potential. Emerging evidence points to inflammation-related microRNAs as crucial molecules to integrate the complex cellular and molecular crosstalk during HCC progression. Thus understanding the mechanisms by which inflammation regulates microRNAs might provide novel and admissible strategies for preventing, diagnosing and treating HCC. In this review, we will update three hypotheses of hepatocarcinogenesis and elaborate the most predominant inflammation signaling pathways, i.e. IL-6/STAT3 and NF-κB. We also try to summarize the crucial tumor-promoting and tumor-suppressing microRNAs and detail how they regulate HCC initiation and progression and collaborate with other critical modulators in this review.

The Plasticizer Bisphenol A Perturbs the Hepatic Epigenome: A Systems Level Analysis of the miRNome

Ubiquitous exposure to bisphenol A (BPA), an endocrine disruptor (ED), has raised concerns for both human and ecosystem health. Epigenetic factors, including microRNAs (miRNAs), are key regulators of gene expression during cancer. The effect of BPA exposure on the zebrafish epigenome remains poorly characterized. Zebrafish represents an excellent model to study cancer as the organism develops a disease that resembles human cancer. Using zebrafish as a systems toxicology model, we hypothesized that chronic BPA-exposure impacts the miRNome in adult zebrafish and establishes an epigenome more susceptible to cancer development. After a 3 week exposure to 100 nM BPA, RNA from the liver was extracted to perform high throughput mRNA and miRNA sequencing. Differential expression (DE) analyses comparing BPA-exposed to control specimens were performed using established bioinformatics pipelines. In the BPA-exposed liver, 6188 mRNAs and 15 miRNAs were differently expressed (q ≤ 0.1). By analyzing human orthologs of the DE zebrafish genes, signatures associated with non-alcoholic fatty liver disease (NAFLD), oxidative phosphorylation, mitochondrial dysfunction and cell cycle were uncovered. Chronic exposure to BPA has a significant impact on the liver miRNome and transcriptome in adult zebrafish with the potential to cause adverse health outcomes including cancer.

microRNA-34a overexpression inhibits cell migration and invasion via regulating SIRT1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most common types of malignancy with high mortality and morbidity rates. Previous studies have suggested that microRNAs (miRs) serve pivotal functions in various types of tumor. The aim of the present study was to assess the association between miR-34a expression and HCC cell migration and invasion, and the potential underlying mechanisms. The miR-34a overexpression vector or scramble control was transfected into human Hep3B and Huh7 cell lines. Transwell assays, and Matrigel and wound healing assays were used to detect the effects of miR-34a expression on HCC cell invasion and migration, respectively. The expression of miR-34a and the mRNA expression of other associated proteins were detected using quantitative reverse transcription polymerase chain reaction, and protein levels were measured using western blot analysis. Compared with the control, miR-34a expression was significantly downregulated in Hep3B and Huh7 cells, but this was reversed by the transfection with exogenous miR-34a (P<0.01). The number of migrated or invaded cells was significantly reduced by the overexpression of miR-34a in Hep3B or Huh7 cells (P<0.01). The expression of sirtuin 1 was upregulated, while the level of acetylate-p53 was downregulated by overexpression of miR-34a. Taken together, the results of the present study suggested that the overexpression of miR-34a may have suppressed HCC metastasis via inhibited cell migration and invasion.

MiR-199a-5p and let-7c cooperatively inhibit migration and invasion by targeting MAP4K3 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a high recurrence rate, and patients exhibit poor survival mainly because intrahepatic metastasis is common. We previously reported that let-7c down-regulation is significantly associated with poor differentiation level in HCC. In the present study, we demonstrate that miR-199a-5p and let-7c are frequently down-regulated in HCC cells and tissues, and low expression of miR-199a-5p is correlated with tumor size, liver envelope invasion. Furthermore, miR-199a-5p and let-7c cooperatively inhibit HCC cell migration and invasion in vitro. MAP4K3 is identified as the direct target of miR-199a-5p and let-7c and this regulation is further confirmed by luciferase reporter assays and Western blotting. In addition, MAP4K3 functions as a metastasis promoter since the results demonstrate that MAP4K3 could promote HCC cell migration and invasion. We also find that miR-199a-5p and let-7c increase the sensitivity of HCC cells to sorafenib.

Non-coding RNA in hepatocellular carcinoma: Mechanisms, biomarkers and therapeutic targets

The majority of the human genome is not translated into proteins but can be transcribed into RNA. Even though the resulting non-coding RNAs (ncRNAs) do not encode for proteins, they contribute to diseases such as cancer. Here, we review examples of the functions of ncRNAs in liver cancer and their potential use for the detection and treatment of liver cancer.

Immune responses in DAA treated chronic hepatitis C patients with and without prior RG-101 dosing

Background & aims

With the introduction of DAA’s, the majority of treated chronic hepatitis C patients (CHC) achieve a viral cure. The exact mechanisms by which the virus is cleared after successful therapy, is still unknown. The aim was to assess the role of the immune system and miRNA levels in acquiring a sustained virological response after DAA treatment in CHC patients with and without prior RG-101 (antimiR-122) dosing.

Methods

In this multicenter, investigator-initiated study, 29 patients with hepatitis C virus (HCV) genotype 1 (n = 11), 3 (n = 17), or 4 (n = 1) infection were treated with sofosbuvir and daclatasvir ± ribavirin. 18 patients were previously treated with RG-101. IP-10 levels were measured by ELISA. Ex vivo HCV-specific T cell responses were quantified in IFN-γ-ELISpot assays. Plasma levels of miR-122 were measured by qPCR.

Results

All patients had an SVR12. IP-10 levels rapidly declined during treatment, but were still elevated 24 weeks after treatment as compared to healthy controls (median 53.82 and 39.4 pg/mL, p = 0.02). Functional IFN-γ HCV-specific T cell responses did not change by week 12 of follow-up (77.5 versus 125 SFU/106 PBMC, p = 0.46). At follow-up week 12, there was no difference in plasma miR-122 levels between healthy controls and patients with and without prior RG-101 dosing.

Conclusions

Our data shows that successful treatment of CHC patients with and without prior RG-101 dosing results in reduction of broad immune activation, and normalisation of miR-122 levels (EudraCT: 2014-002808-25).

Argonaute CLIP Defines a Deregulated miR-122-Bound Transcriptome that Correlates with Patient Survival in Human Liver Cancer

MicroRNA-122, an abundant and conserved liver-specific miRNA, regulates hepatic metabolism and functions as a tumor suppressor, yet systematic and direct biochemical elucidation of the miR-122 target network remains incomplete. To this end, we performed Argonaute crosslinking immunoprecipitation (Argonaute [Ago]-CLIP) sequencing in miR-122 knockout and control mouse livers, as well as in matched human hepatocellular carcinoma (HCC) and benign liver tissue to identify miRNA target sites transcriptome-wide in two species. We observed a majority of miR-122 binding on 3' UTRs and coding exons followed by extensive binding to other genic and non-genic sites. Motif analysis of miR-122-dependent binding revealed a G-bulged motif in addition to canonical motifs. A large number of miR-122 targets were found to be species specific. Upregulation of several common mouse and human targets, most notably BCL9, predicted survival in HCC patients. These results broadly define the molecular consequences of miR-122 downregulation in hepatocellular carcinoma.

Pivotal roles of glycogen synthase-3 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world, and represents the second most frequently cancer and third most common cause of death from cancer worldwide. At advanced stage, HCC is a highly aggressive tumor with a poor prognosis and with very limited response to common therapies. Therefore, there is still the need for new effective and well-tolerated therapeutic strategies. Molecular-targeted therapies hold promise for HCC treatment. One promising molecular target is the multifunctional serine/threonine kinase glycogen synthase kinase 3 (GSK-3). The roles of GSK-3β in HCC remain controversial, several studies suggested a possible role of GSK-3β as a tumor suppressor gene in HCC, whereas, other studies indicate that GSK-3β is a potential therapeutic target for this neoplasia. In this review, we will focus on the different roles that GSK-3 plays in HCC and its interaction with signaling pathways implicated in the pathogenesis of HCC, such as Insulin-like Growth Factor (IGF), Notch, Wnt/β-catenin, Hedgehog (HH), and TGF-β pathways. In addition, the pivotal roles of GSK3 in epithelial-mesenchymal transition (EMT), invasion and metastasis will be also discussed.

Joint Covariate Detection on Expression Profiles for Identifying MicroRNAs Related to Venous Metastasis in Hepatocellular Carcinoma

Expression profiles of cancer are generally composed of three dimensions including gene probes, patients (e.g., metastasis or non-metastasis) and tissues (i.e., cancer or normal cells of a patient). In order to combine these three dimensions, we proposed a joint covariate detection that not only considered projections on gene probes and tissues simultaneously, but also concentrated on distinguishing patients into different groups. Due to highly lethal malignancy of hepatocellular carcinoma, we chose data GSE6857 to testify the effectiveness of our method. A bootstrap and accumulation strategy was introduced in, which could select candidate microRNAs to distinguish metastasis from non-metastasis patient group. Two pairs of microRNAs were further selected. Each component of either significant microRNA pair was derived from different cliques. Targets were sought and pathway analysis were made, which might reveal the mechanism of venous metastasis in primary hepatocellular carcinoma.

Flux balance analysis predicts Warburg-like effects of mouse hepatocyte deficient in miR-122a

The liver is a vital organ involving in various major metabolic functions in human body. MicroRNA-122 (miR-122) plays an important role in the regulation of liver metabolism, but its intrinsic physiological functions require further clarification. This study integrated the genome-scale metabolic model of hepatocytes and mouse experimental data with germline deletion of Mir122a (Mir122a^–/–) to infer Warburg-like effects. Elevated expression of MiR-122a target genes in Mir122a^–/–mice, especially those encoding for metabolic enzymes, was applied to analyze the flux distributions of the genome-scale metabolic model in normal and deficient states. By definition of the similarity ratio, we compared the flux fold change of the genome-scale metabolic model computational results and metabolomic profiling data measured through a liquid-chromatography with mass spectrometer, respectively, for hepatocytes of 2-month-old mice in normal and deficient states. The Ddc gene demonstrated the highest similarity ratio of 95% to the biological hypothesis of the Warburg effect, and similarity of 75% to the experimental observation. We also used 2, 6, and 11 months of mir-122 knockout mice liver cell to examined the expression pattern of DDC in the knockout mice livers to show upregulated profiles of DDC from the data. Furthermore, through a bioinformatics (LINCS program) prediction, BTK inhibitors and withaferin A could downregulate DDC expression, suggesting that such drugs could potentially alter the early events of metabolomics of liver cancer cells.

For almost a century, researchers have known that cancer cells have an abnormal metabolism and utilize glucose differently than normal cells do. Aerobic glycolysis or the Warburg effect in cancer cells involves elevated glucose uptake with lactic acid production in the presence of oxygen. MicroRNAs have recently been discovered to be key metabolic regulators that mediate the fine tuning of genes that are involved directly or indirectly in cancer metabolism. MicroRNA-122 (miR-122) plays an important role in the regulation of liver metabolism, but its intrinsic physiological functions require further clarification. This study integrated the genome-scale metabolic modeling (GSMM) of hepatocytes and mouse experimental data with germline deletion of Mir122a (Mir122a^–/–) to infer Warburg-like effects. In silico and in vivo observations indicated that DDC overexpression induced Warburg effect in hepatocyte. Furthermore, through a bioinformatics prediction, BTK inhibitors and withaferin A could downregulate DDC expression, suggesting that such drugs could potentially alter the early events of metabolomics of liver cancer cells.

The hepatocyte-specific HNF4α/miR-122 pathway contributes to iron overload-mediated hepatic inflammation

Hepatic iron overload (IO) is a major complication of transfusional therapy. It was generally thought that IO triggers substantial inflammatory responses by producing reactive oxygen species in hepatic macrophages. Recently, a decrease in microRNA-122 (miR-122) expression was observed in a genetic knockout (Hfe^-/-) mouse model of IO. Because hepatocyte-enriched miR-122 is a key regulator of multiple hepatic pathways, including inflammation, it is of interest whether hepatocyte directly contributes to IO-mediated hepatic inflammation. Here, we report that IO induced similar inflammatory responses in human primary hepatocytes and Thp-1-derived macrophages. In the mouse liver, IO resulted in altered expression of not only inflammatory genes but also >230 genes that are known targets of miR-122. In addition, both iron-dextran injection and a 3% carbonyl iron-containing diet led to upregulation of hepatic inflammation, which was associated with a significant reduction in HNF4α expression and its downstream target, miR-122. Interestingly, the same signaling pathway was changed in macrophage-deficient mice, suggesting that macrophages are not the only target of IO. Most importantly, hepatocyte-specific overexpression of miR-122 rescued IO-mediated hepatic inflammation. Our findings indicate the direct involvement of hepatocytes in IO-induced hepatic inflammation and are informative for developing new molecular targets and preventative therapies for patients with major hemoglobinopathy.

MicroRNA-493 suppresses hepatocellular carcinoma tumorigenesis through down-regulation of anthrax toxin receptor 1 (ANTXR1) and R-Spondin 2 (RSPO2)

Hepatocellular carcinoma (HCC) is known as a highly prevalent cancer with a poor prognosis and short survival time, despite intensive research and clinical efforts. Increasing numbers of studies have reported that microRNAs are involved in the malignant behavior of hepatocellular carcinoma cells via directly targeting multiple oncogenes or tumor suppressors. Here, we report that the expression of microRNA-493 (miR-493) is decreased in HCC cell lines and in tumor tissues. Overexpression of miR-493 in HCC cells dramatically inhibited cell proliferation and colony-formation in vitro and inhibited tumor formation of HCC cell xenografts in vivo. miR-493 also suppressed cell migration and invasion in HCC cell lines. Novel targets ANTXR1 and RSPO2 were confirmed to be suppressed by miR-493 directly, and overexpression of ANTXR1 and RSPO2 could restore tumorigenesis in miR-493 treated HCC cell. Moreover, Wnt/β-catenin signaling pathway, which was reported to be activated by ANTXR1 and RSPO2, was also inhibited by miR-493 overexpression and might be involved in anti-tumor function of miR-493. These findings suggest that miR-493 acts as a negative regulator in hepatocellular carcinoma progression and may be a potential therapeutic target for HCC.

Biomarkers in hepatocellular carcinoma: an overview

Current methods for HCC diagnosis have not an optimal diagnostic accuracy. The detection of more than one biomarker seems to improve their individual performance and provide an accurate HCC diagnosis approach. Individual gene expression seems to influence whether or not the treatment is successful, since several molecules have interfere with cancer associated pathways and have been related to poor prognosis which condition the lack of effective treatment options. Areas covered: Novel biomarkers have been proposed as a useful tool in each patient prognosis. This article aims to review the recent evidence based on HCC biomarkers which seems to have a regulative role according to tumor cell development leading to a specific biological response. Epigenetic regulation, miRNAs, and genome sequencing analysis propose molecular expression signatures as novel biomarkers which allowed achieve the major goal for the use of biomarkers in clinical practice. Moreover, a deeper analysis for determine the diagnostic accuracy of biomarkers has been made. Expert commentary: To improve of methodological designs and sample sizes are needed in order to support the role of biomarkers in HCC. Furthermore, is necessary to consider HCC etiologies and all clinic disease context to carried out clinical phase studies to thrust biomarkers application.

Liver physiological polyploidization: MicroRNA-122 a key regulator

Polyploidy is defined as an increase in genome DNA content and is observed in all mammalian species. Polyploidy is a common characteristic of hepatocytes. Polyploidization occurs mainly during liver development, but also in adults with increasing age or due to cellular stress. During liver development, hepatocytes polyploidization occurs through cytokinesis failure leading to the genesis of binucleate hepatocytes. Recently, Hsu et al. demonstrated that miR-122 is a key regulator of hepatic binucleation. In fact, during liver development, miR-122 directly antagonizes procytokinesis targets and thus induces cytokinesis failure leading to the genesis of binucleate hepatocytes.

Regulation of hepatic microRNA expression by hepatocyte nuclear factor 4 alpha

AIM

To uncover the role of hepatocyte nuclear factor 4 alpha (HNF4α) in regulating hepatic expression of microRNAs.

METHODS

Microarray and real-time PCR were used to determine hepatic expression of microRNAs in young-adult mice lacking Hnf4α expression in liver (Hnf4α-LivKO). Integrative genomics viewer software was used to analyze the public chromatin immunoprecipitation-sequencing datasets for DNA-binding of HNF4α, RNA polymerase-II, and histone modifications to loci of microRNAs in mouse liver and human hepatoma cells. Dual-luciferase reporter assay was conducted to determine effects of HNF4α on the promoters of mouse and human microRNAs as well as effects of microRNAs on the untranslated regions (3’UTR) of two genes in human hepatoma cells.

RESULTS

Microarray data indicated that most microRNAs remained unaltered by Hnf4α deficiency in Hnf4α-LivKO mice. However, certain liver-predominant microRNAs were down-regulated similarly in young-adult male and female Hnf4α-LivKO mice. The down-regulation of miR-101, miR-192, miR-193a, miR-194, miR-215, miR-802, and miR-122 as well as induction of miR-34 and miR-29 in male Hnf4α-LivKO mice were confirmed by real-time PCR. Analysis of public chromatin immunoprecipitation-sequencing data indicates that HNF4α directly binds to the promoters of miR-101, miR-122, miR-194-2/miR-192 and miR-193, which is associated with histone marks of active transcription. Luciferase reporter assay showed that HNF4α markedly activated the promoters of mouse and human miR-101b/miR-101-2 and the miR-194/miR-192 cluster. Additionally, miR-192 and miR-194 significantly decreased activities of luciferase reporters for the 3’UTR of histone H3F3 and chromodomain helicase DNA binding protein 1 (CHD1), respectively, suggesting that miR-192 and miR-194 might be important in chromosome remodeling through directly targeting H3F3 and CHD1.

CONCLUSION

HNF4α is essential for hepatic basal expression of a group of liver-enriched microRNAs, including miR-101, miR-192, miR-193a, miR-194 and miR-802, through which HNF4α may play a major role in the post-transcriptional regulation of gene expression and maintenance of the epigenome in liver.

Hypoxia Causes Downregulation of Dicer in Hepatocellular Carcinoma, Which Is Required for Upregulation of Hypoxia-Inducible Factor 1α and Epithelial-Mesenchymal Transition

Purpose: A role of Dicer, which converts precursor miRNAs to mature miRNAs, in the tumor-promoting effect of hypoxia is currently emerging in some tumor entities. Its role in hepatocellular carcinoma (HCC) is unknown.Experimental Design: HepG2 and Huh-7 cells were stably transfected with an inducible Dicer expression vector and were exposed to hypoxia/normoxia. HepG2-Dicer xenografts were established in nude mice; hypoxic areas and Dicer were detected in HCC xenografts and HCCs from mice with endogenous hepatocarcinogenesis; and epithelial-mesenchymal transition (EMT) markers were analyzed by immunohistochemistry or by immunoblotting. The correlation between Dicer and carbonic anhydrase 9 (CA9), a marker of hypoxia, was investigated in resected human HCCs.Results: Hypoxia increased EMT markers in vitro and in vivo and led to a downregulation of Dicer in HCC cells. The levels of Dicer were downregulated in hypoxic tumor regions in mice with endogenous hepatocarcinogenesis and in HepG2 xenografts. In human HCCs, the levels of Dicer correlated inversely with those of CA9, indicating that the negative regulation of Dicer by hypoxia also applies to HCC patients. Forced expression of Dicer prevented the hypoxia-induced increase in hypoxia-inducible factor 1α (HIF1α), HIF2α, hypoxia-inducible genes (CA9, glucose transporter 1), EMT markers, and cell migration.Conclusions: We here identify downmodulation of Dicer as novel essential process in hypoxia-induced EMT in HCC and demonstrate that induced expression of Dicer counteracted hypoxia-induced EMT. Thus, targeting hypoxia-induced downmodulation of Dicer is a promising novel strategy to reduce HCC progression. Clin Cancer Res; 23(14); 3896-905. ©2017 AACR.

High expression of micro RNA-135A in hepatocellular carcinoma is associated with recurrence within 12 months after resection

BACKGROUND

Hepatocellular carcinoma has a dismal prognosis due to recurrence rates of up to 70% after curative resection. Early recurrence is driven by synchronous microscopic intrahepatic metastases. The predictive value of histological parameters is discussed controversially and adjuvant therapy is not established. The aim of this study was to identify patients at high risk for early intrahepatic recurrence by expression profiling of selected micro RNAs.

METHODS

In 52 patients undergoing HCC resection between 2011 and 2014, liver and tumor tissue was collected during surgery. Twelve patients with incomplete data regarding HCC recurrence, secondary liver transplantation, or perioperative death were excluded, leaving 40 patients with early recurrence <12 months (R+) or without recurrence for >24 months (R-) to compare grading, T, L, V, and R status. If tissue quality permitted, micro RNAs were measured in HCC and liver tissue.

RESULTS

Ten women and 30 men (64.0 ± 10.2 years) were analyzed. R+ occurred in 29 patients 6.2 ± 4.5 months after resection. Surveillance of R- was 26.2 ± 5.2 months. High intratumoral expression of miR-135a was associated with high risk of recurrence (HR = 4.2, p = 0.024, time to recurrence 8.8 ± 2.0 vs. 24.8 ± 4.4 months in patients with low miR-135a expression). As expected, T3 status was correlated with early recurrence, while other histological parameters and expression of miR-21, miR-122, and miR-125a did not.

CONCLUSIONS

We show a significant association between high expression of miR-135a and early HCC recurrence. Therefore, high intratumoral miR-135a expression might serve as a novel biomarker to identify patients urgently requiring adjuvant therapy post resection.

Regulation of miRNAs by herbal medicine: An emerging field in cancer therapies

MicroRNAs' expression profiles have recently gained major attention as far as cancer research is concerned. MicroRNAs are able to inhibit target gene expression via binding to the 3' UTR of target mRNA, resulting in target mRNA cleavage or translation inhibition. MicroRNAs play significant parts in a myriad of biological processes; studies have proven, on the other hand, that aberrant microRNA expression is, more often than not, associated with the growth and progression of cancers. MicroRNAs could act as oncogenes (oncomir) or tumor suppressors and can also be utilized as biomarkers for diagnosis, prognosis, and cancer therapy. Recent studies have shown that such herbal extracts as Shikonin, Sinomenium acutum, curcumin, Olea europaea, ginseng, and Coptidis Rhizoma could alter microRNA expression profiles through inhibiting cancer cell development, activating the apoptosis pathway, or increasing the efficacy of conventional cancer therapeutics. Such findings patently suggest that the novel specific targeting of microRNAs by herbal extracts could complete the restriction of tumors by killing the cancerous cells so as to recover survival results in patients diagnosed with malignancies. In this review, we summarized the current research about microRNA biogenesis, microRNAs in cancer, herbal compounds with anti-cancer effects and novel strategies for employing herbal extracts in order to target microRNAs for a better treatment of patients diagnosed with cancer.

Control of HCV Replication With iMIRs, a Novel Anti-RNAi Agent

MicroRNAs (miRNAs) serve important roles in regulating various physiological activities through RNA interference (RNAi). miR-122 is an important mediator of RNAi that is known to control hepatitis C virus (HCV) replication and is being investigated in clinical trials as a target for anti-HCV therapy. In this study, we developed novel oligonucleotides containing non-nucleotide residues, termed iMIRs, and tested their abilities to inhibit miR-122 function. We compared the inhibitory effects of iMIRs and locked nucleic acids (LNAs) on HCV replication in OR6 cells, which contained full-length HCV (genotype 1b) and a luciferase reporter gene. We found that RNA-type iMIRs with bulge-type, imperfect complementarity with respect to miR-122 were 10-fold more effective than LNAs in inhibiting HCV replication and functioned in a dose-dependent manner. Moreover, iMIR treatment of OR6 cells reduced HCV replication without inducing interferon responses or cellular toxicity. Based on these results, we suggest that iMIRs can inhibit HCV replication more effectively than LNAs and are therefore promising as novel antiviral agents.

Inflammation-Induced Expression and Secretion of MicroRNA 122 Leads to Reduced Blood Levels of Kidney-Derived Erythropoietin and Anemia

BACKGROUND & AIMS

Anemia is associated commonly with acute and chronic inflammation, but the mechanisms of their interaction are not clear. We investigated whether microRNA 122 (MIR122), which is generated in the liver and is secreted into the blood, is involved in the development of anemia associated with inflammation.

METHODS

We characterized the primary transcript of the human liver-specific MIR122 using Northern blot, quantitative real-time polymerase chain reaction, and 3' and 5' rapid amplification of cDNA ends analyses. We studied regulation of MIR122 in human hepatocellular carcinoma cell lines (Huh7 and HepG2) as well as in C57BL/6 and mice with disruption of the tumor necrosis factor (Tnf) gene. Liver tissues were collected and analyzed by bioluminescence imaging or immunofluorescence. Inflammation in mice was induced by lipopolysaccharide (LPS) or by cerulein injections. Mice were given 4 successive injections of LPS, leading to inflammation-induced anemia. Steatohepatitis was induced with a choline-deficient, high-fat diet. Hemolytic anemia was stimulated by phenylhydrazine injection. MIR122 was inhibited in mice by tail-vein injection of an oligonucleotide antagonist of MIR122. MicroRNA and messenger RNA levels were determined by quantitative real-time polymerase chain reaction.

RESULTS

The primary transcript of MIR122 spanned 5 kb, comprising 3 exons; the third encodes MIR122. Within the MIR122 promoter region we identified a nuclear factor-κB binding site and showed that RELA (NF-κB p65 subunit), as well as activators of NF-κB (TNF and LPS), increased promoter activity of MIR122. Administration of LPS to mice induced secretion of MIR122 into blood, which required TNF. Secreted MIR122 reached the kidney and reduced expression of erythropoietin (Epo), which we identified as a MIR122 target gene. Injection of mice with an oligonucleotide antagonist of MIR122 increased blood levels of EPO, reticulocytes, and hemoglobin. We found an inverse relationship between blood levels of MIR122 and EPO in mice with acute pancreatitis or steatohepatitis, and also in patients with acute inflammation.

CONCLUSION

In mice, we found that LPS-induced inflammation increases blood levels of MIR122, which reduces expression of Epo in the kidney; this is a mechanism of inflammation-induced anemia. Strategies to block MIR122 in patients with inflammation could reduce the development or progression of anemia.

The liver-specific microRNA-122*, the complementary strand of microRNA-122, acts as a tumor suppressor by modulating the p53/mouse double minute 2 homolog circuitry

The tumor suppressor p53 is a central regulator of signaling pathways that controls the cell cycle and maintains the integrity of the human genome. p53 level is regulated by mouse double minute 2 homolog (Mdm2), which marks p53 for proteasomal degradation. The p53-Mdm2 circuitry is subjected to complex regulation by a variety of mechanisms, including microRNAs (miRNAs). We found a novel effector of this regulatory circuit, namely, miR-122*, the passenger strand of the abundantly expressed liver-specific miR-122. Here, we demonstrate that miR-122* levels are reduced in human hepatocellular carcinoma (HCC). We found that miR-122* targets Mdm2, thus participating as an important player in the p53-Mdm2 circuitry. Moreover, we observed significant negative correlation between levels of miR-122* and Mdm2 in a large set of human HCC samples. In vivo tumorigenicity assays demonstrate that miR-122* is capable of inhibiting tumor growth, emphasizing the tumor-suppressor characteristics of this miRNA. Furthermore, we show that blocking miR-122 in murine livers with an antagomiR-122 (miRNA inhibitor) results in miR-122* accumulation, leading to Mdm2 repression followed by elevated p53 protein levels.

CONCLUSION

miR-122*, the passenger strand of miR-122, regulates the activity of p53 by targeting Mdm2. Importantly, similarly to miR-122, miR-122* is significantly down-regulated in human HCC. We therefore propose that miR-122* is an important contributor to the tumor suppression activity previously attributed solely to miR-122. (Hepatology 2016;64:1623-1636).

Insights for hepatitis C virus related hepatocellular carcinoma genetic biomarkers: Early diagnosis and therapeutic intervention

The current review explores the role of emerging molecular contributing factors in liver carcinogenesis on top of hepatitis C virus (HCV). Here we will try to discuss the role genetic and epigenetic factors in pathogenesis of hepatocellular carcinoma. Understanding the role of these factors will help in discovering the mystery of liver carcinogenesis on top of chronic HCV infection. Moreover, use of the studied molecular factors will provide the hepatologists with tailored diagnostic promising biomarkers and flatten the way for establishment of emerging molecular treatment based on exploring the molecular subscription of this aggressive liver cancer.

Plasma miR-122 and miR-200 family are prognostic markers in colorectal cancer

Circulating microRNAs (miRNAs) have been proposed as minimally invasive prognostic markers for various types of cancers, including colorectal cancer (CRC), the third most diagnosed cancer worldwide. We aimed to evaluate the levels of circulating miRNAs that might serve as markers for CRC prognosis and survival. We included plasma samples of 543 CRC patients with stage I-IV disease from a population-based study carried out in Germany. After comprehensive evaluation of current literature, 95 miRNAs were selected and measured with Custom TaqMan® Array MicroRNA Cards. Plasma samples of non-metastatic and metastatic colon cancer patients, each group consisting of ten patients with 'good' and ten patients with 'bad' prognosis were screened. Identified candidate miRNAs were further validated by RT-qPCR in the whole study cohort. The association of the miRNA levels with patients' survival and the prognostic subtypes was analyzed with uni- and multivariate logistic regression and Cox proportional hazards regression models. Increased miR-122 levels were associated with a 'bad' prognostic subtype in metastatic CRC (Odds ratio: 1.563, 95% confidence interval (CI): 1.038-2.347) and a shorter relapse-free survival and overall survival for non-metastatic (Hazard ratio (HR): 1.370, 95% CI: 1.028-1.825; HR: 1.353, 95% CI: 1.002-1.828) and metastatic (HR: 1.264, 95% CI: 1.050-1.520; HR: 1.292, 95% CI: 1.078-1.548) CRC patients. Additionally, several members of the miR-200 family showed associations with patients' prognosis and correlations to clinicopathological characteristics. The here identified miRNA markers, miR-122 and the miR-200 family members, could be of use in the development of a multi-marker blood test for CRC prognosis.

Molecular alterations in the carcinogenesis and progression of hepatocellular carcinoma: Tumor factors and background liver factors

Although hepatocellular carcinoma (HCC) is associated with poor prognosis worldwide, the molecular mechanisms underlying the carcinogenesis and progression of this disease remain unclear. Several tumor characteristics have previously been demonstrated to be prognostic factors of survival following hepatic resection, or the recurrence of HCC or other types of cancer. Comparisons of normal tissues and HCC tumor tissues have revealed the presence of numerous molecular alterations in HCC, including genetic and epigenetic mechanisms, particularly mutations in certain genes and DNA methylation in the promoter regions of tumor-suppressor genes. A number of studies have previously used array analysis to detect variations in the expression levels of cancer-associated genes and microRNAs, and in DNA methylation. However, an investigation of HCC tumor tissues may not determine the effect of noncancerous liver tissues (background liver) in patients with HCC. As HCC may recur multicentrically following resection, a damaged or chronically diseased HCC background liver may be considered as a pre-cancerous organ. Therefore, the influence of the background liver on HCC requires further study. Detailed studies regarding the background liver may be essential for the improved understanding of the carcinogenesis and progression of this malignancy; however only a few studies have investigated the microenvironment of the HCC background liver. The present review discusses prior molecular studies of hepatocarcinogenesis that focus on HCC and background liver tissues.

Upregulated in Hepatitis B virus-associated hepatocellular carcinoma cells, miR-331-3p promotes proliferation of hepatocellular carcinoma cells by targeting ING5

Hepatitis B virus (HBV) is a major risk factor for development and progression of hepatocellular carcinoma (HCC). It has been reported that viral infection can interfere with cellular microRNA (miRNA) expression and participate in the pathogenesis of oncogenicity. Our miRNAs array data indicated that miR-331-3p expression in HCC cell lines increased, but the relationship between miR-331-3p expression and HBV activity is unclear. Here, we observed elevated expression of miR-331-3p in different HCC cell lines expressing HBV. HBV, especially HBx, promotes miR-331-3p expression by enhancing its promoter activity. Using a miRNA target prediction database miRBase, we identified ING5 to be a novel target gene of miR-331-3p. miR-331-3p could inhibit ING5 expression by directly targeting its 3′-untranslated region (3′-UTR). As predicted, HBV was confirmed to repress ING5 at both mRNA and protein levels by promoting miR-331-3p expression. Our result indicated that miR-331-3p expression promotes proliferation of SMMC7721 cells by inhibiting ING5. ING5 overexpression promoted cell apoptosis in HCC cell lines. We also found ING5 expression was decreased in tumor tissue of HCC patient with HBV infection compared to its expression in para-carcinoma tissues. Conclusion: These results showed that miR-331-3p is upregulated by HBV and promotes proliferation of HCC cells though repression of ING5 expression. These data provide new insights for understanding the mechanisms of HBV-related HCC pathogenesis.

Unraveling the Mysterious Interactions Between Hepatitis C Virus RNA and Liver-Specific MicroRNA-122

Many viruses encode or subvert cellular microRNAs (miRNAs) to aid in their gene expression, amplification strategies, or pathogenic signatures. miRNAs typically downregulate gene expression by binding to the 3' untranslated region of their mRNA targets. As a result, target mRNAs are translationally repressed and subsequently deadenylated and degraded. Curiously, hepatitis C virus (HCV), a member of the Flaviviridae family, recruits two molecules of liver-specific microRNA-122 (miR-122) to the 5' end of its genome. In contrast to the canonical activity of miRNAs, the interactions of miR-122 with the viral genome promote viral RNA accumulation in cultured cells and in animal models of HCV infection. Sequestration of miR-122 results in loss of viral RNA both in cell culture and in the livers of chronic HCV-infected patients. This review discusses the mechanisms by which miR-122 is thought to enhance viral RNA abundance and the consequences of miR-122-HCV interactions. We also describe preliminary findings from phase II clinical trials in patients treated with miR-122 antisense oligonucleotides.

Hepatitis B virus X protein mediated suppression of miRNA-122 expression enhances hepatoblastoma cell proliferation through cyclin G1-p53 axis

Background

Hepatitis B virus (HBV) X protein (HBx) reported to be associated with pathogenesis of hepatocellular carcinoma (HCC) and miR-122 expression is down regulated in HCC. Previous studies reported miR-122 targets cyclin G1 (CCNG1) expression and this in turn abolishes p53-mediated inhibition of HBV replication. Here we investigated the involvement of HBx protein in the modulation of miR-122 expression in hepatoblastoma cells.

Methods

Expression of miR-122 was measured in HepG2 cells transfected with HBx plasmid (HBx-HepG2), full length HBV genome (HBV-HepG2) and in constitutively HBV synthesizing HepG2.2.15 cells. CCNG1 mRNA (a direct target of miR-122) and protein expressions were also measured in both HBx-HepG2, HBV-HepG2 cells and in HepG2.2.15 cells. miR-122 expressions were analyzed in HBx-HepG2, HBV-HepG2 and in HepG2.2.15 cells after treatment with HBx mRNA specific siRNA. Expressions of p53 mRNA and protein which is negatively regulated by CCNG1 were analyzed in HBx transfected HepG2 cells; X silenced HBx-HepG2 cells and X silenced HepG2.2.15 cells. HBx induced cell proliferation in HepG2 cells was measured by cell proliferation assay. Flow cytometry was used to evaluate changes in cell cycle distribution. Expression of cell cycle markers were measured by real time PCR.

Results

Expression of miR-122 was down regulated in HBx-HepG2, HBV-HepG2 and also in HepG2.2.15 cell line compared to control HepG2 cells. CCNG1 expression was found to be up regulated in HBx-HepG2, HBV-HepG2 cells and in HepG2.2.15 cells. Following siRNA mediated silencing of HBx expression; increased miR-122 levels were documented in HBx-HepG2, HBV-HepG2 and in HepG2.2.15 cells. HBx silencing in HBx-HepG2 and HepG2.2.15 cells also resulted in increased p53 expression. FACS analysis and assessment of expressions of cell cycle markers revealed HBx induced a release from G1/S arrest in HepG2 cells. Further, cell proliferation assay showed HBx promoted proliferation of HepG2 cell.

Conclusion

Our study revealed that HBx induced down regulation of miR-122 expression that consequently increased CCNG1 expression. This subsequently caused cell proliferation and release from G1/S arrest in malignant hepatocytes. The study provides the potential to utilize the HBx-miR-122 interaction as a therapeutic target to limit the development of HBV related HCC.

Combined low miR-34s are associated with unfavorable prognosis in children with hepatoblastoma: A Chinese population-based study

PURPOSE

The aim of this study is to identify the association between miR-34's family and the prognosis of HB in a large Asian cohort and to explore the interaction of miR-34 with other independent risk factors in the process of affecting prognosis of HB.

METHODS

We retrospectively reviewed 78 children with HB (36 female, 42 male) managed in our institutions between 2007 and 2014. The expression of miR-34 was detected by real-time PCR. Prognostic factors were evaluated using Kaplan-Meier curves and Cox proportional hazards models.

RESULTS

For the entire cohort of 76 patients, The normalized real-time PCR results showed that all three miRNAs were deregulated in tumor tissues as compared with corresponding noncancerous tissue samples. Descriptive survival statistics and Kaplan-Meier curves suggested that AFP levels, metastases, vascular invasion, PRETEXT stage and miR-34 had prognostic significance in this relatively selected cohort. After that we made miR-34 into different combinations. The results demonstrated that combined low miR-34a and miR-34b (HR:2.212, P=0.016), combined low miR-34a and miR-34c (HR:1.984, P=0.025) and combined low miR-34a, miR-34b and miR-34c (HR:3.569, P=0.001) were independent prognostic factors of HB. We further conduct stratified analysis of the impact of other identified risk factors on the combined low of three miR-34.

CONCLUSIONS

In this study, we found that miR-34s were deregulated in tumor tissues compared with corresponding noncancerous tissue samples. We also confirmed that combined low miR-34 is an independent prognostic factor related with HB.

miR-122-mediated translational repression of PEG10 and its suppression in human hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC), a primary liver malignancy, is the most common cancer in males and fourth common cancer in females in Taiwan. HCC patients usually have a poor prognosis due to late diagnosis. It has been classified as a complex disease because of the heterogeneous phenotypic and genetic traits of the patients and a wide range of risk factors. Micro (mi)RNAs regulate oncogenes and tumor suppressor genes that are known to be dysregulated in HCC. Several studies have found an association between downregulation of miR-122, a liver-specific miRNA, and upregulation of paternally expressed gene 10 (PEG10) in HCC; however, the correlation between low miR-122 and high PEG10 levels still remains to be defined and require more investigations to evaluate their performance as an effective prognostic biomarker for HCC.

Methods

An in silico approach was used to isolate PEG10, a potential miR-122 target implicated in HCC development. miR-122S binding sites in the PEG10 promoter were evaluated with a reporter assay. The regulation of PEG10 by miR-122S overexpression was examined by quantitative RT-PCR, western blotting, and immunohistochemistry in miR-122 knockout mice and liver tissue from HCC patients. The relationship between PEG10 expression and clinicopathologic features of HCC patients was also evaluated.

Results

miR-122 downregulated the expression of PEG10 protein through binding to 3′-untranslated region (UTR) of the PEG10 transcript. In miR-122 knockout mice and HCC patients, the deficiency of miR-122 was associated with HCC progression. The expression of PEG10 was increased in 57.3 % of HCC as compared to paired non-cancerous tissue samples. However, significant upregulation was detected in 56.5 % of patients and was correlated with Okuda stage (P = 0.05) and histological grade (P = 0.001).

Conclusions

miR-122 suppresses PEG10 expression via direct binding to the 3′-UTR of the PEG10 transcript. Therefore, while PEG10 could not be an ideal diagnostic biomarker for HCC but its upregulation in HCC tissue still has predictive value for HCC prognosis.

Hepatitis C Virus Core Protein Promotes miR-122 Destabilization by Inhibiting GLD-2

The liver-specific microRNA miR-122, which has essential roles in liver development and metabolism, is a key proviral factor for hepatitis C virus (HCV). Despite its crucial role in the liver and HCV life cycle, little is known about the molecular mechanism of miR-122 expression regulation by HCV infection. Here, we show that the HCV core protein downregulates the abundance of miR-122 by promoting its destabilization via the inhibition of GLD-2, a non-canonical cytoplasmic poly(A) polymerase. The decrease in miR-122 expression resulted in the dysregulation of the known functions of miR-122, including its proviral activity for HCV. By high-throughput sequencing of small RNAs from human liver biopsies, we found that the 22-nucleotide (nt) prototype miR-122 is modified at its 3' end by 3'-terminal non-templated and templated nucleotide additions. Remarkably, the proportion of miR-122 isomers bearing a single nucleotide tail of any ribonucleotide decreased in liver specimens from patients with HCV. We found that these single-nucleotide-tailed miR-122 isomers display increased miRNA activity and stability over the 22-nt prototype miR-122 and that the 3'-terminal extension is catalyzed by the unique terminal nucleotidyl transferase activity of GLD-2, which is capable of adding any single ribonucleotide without preference of adenylate to the miR-122 3' end. The HCV core protein specifically inhibited GLD-2, and its interaction with GLD-2 in the cytoplasm was found to be responsible for miR-122 downregulation. Collectively, our results provide new insights into the regulatory role of the HCV core protein in controlling viral RNA abundance and miR-122 functions through miR-122 stability modulation.

Gα12 overexpressed in hepatocellular carcinoma reduces microRNA-122 expression via HNF4α inactivation, which causes c-Met induction

MicroRNA-122 (miR-122) is implicated as a regulator of physiological and pathophysiological processes in the liver. Overexpression of Gα₁₂ is associated with overall survival in patients with hepatocellular carcinoma (HCC). Array-based miRNA profiling was performed on Huh7 stably transfected with activated Gα₁₂ to find miRNAs regulated by the Gα₁₂ pathway; among them, miR-122 was most greatly repressed. miR-122 directly inhibits c-Met expression, playing a role in HCC progression. Gα₁₂ destabilized HNF4α by accelerating ubiquitination, impeding constitutive expression of miR-122. miR-122 mimic transfection diminished the ability of Gα₁₂ to increase c-Met and to activate ERK, STAT3, and Akt/mTOR, suppressing cell proliferation with augmented apoptosis. Consistently, miR-122 transfection prohibited tumor cell colony formation and endothelial tube formation. In a xenograft model, Gα₁₂ knockdown attenuated c-Met expression by restoring HNF4α levels, and elicited tumor cell apoptosis but diminished Ki67 intensities. In human HCC samples, Gα₁₂ levels correlated to c-Met and were inversely associated with miR-122. Both miR-122 and c-Met expression significantly changed in tumor node metastasis (TNM) stage II/III tumors. Moreover, changes in Gα₁₂ and miR-122 levels discriminated recurrence-free and overall survival rates of HCC patients. Collectively, Gα₁₂ overexpression in HCC inhibits MIR122 transactivation by inactivating HNF4α, which causes c-Met induction, contributing to cancer aggressiveness.

MicroRNA-548a-5p promotes proliferation and inhibits apoptosis in hepatocellular carcinoma cells by targeting Tg737

AIM: To investigate whether Tg737 is regulated by microRNA-548a-5p (miR-548a-5p), and correlates with hepatocellular carcinoma (HCC) cell proliferation and apoptosis.

METHODS: Assays of loss of function of Tg737 were performed by the colony formation assay, CCK assay and cell cycle assay in HCC cell lines. The interaction between miR-548a-5p and its downstream target, Tg737, was evaluated by a dual-luciferase reporter assay and quantitative real-time polymerase chain reaction. Tg737 was then up-regulated in HCC cells to evaluate its effect on miR-548a-5p regulation. HepG2 cells stably overexpressing miR-548a-5p or miR-control were also subcutaneously inoculated into nude mice to evaluate the effect of miR-548a-5p up-regulation on in vivo tumor growth. As the final step, the effect of miR-548a-5p on the apoptosis induced by cisplatin was evaluated by flow cytometry.

RESULTS: Down-regulation of Tg737, which is a target gene of miR-548a-5p, accelerated HCC cell proliferation, and miR-548a-5p promoted HCC cell proliferation in vitro and in vivo. Like the down-regulation of Tg737, overexpression of miR-548a-5p in HCC cell lines promoted cell proliferation, increased colony forming ability and hampered cell apoptosis. In addition, miR-548a-5p overexpression increased HCC cell growth in vivo. MiR-548a-5p down-regulated Tg737 expression through direct contact with its 3’ untranslated region (UTR), and miR-548a-5p expression was negatively correlated with Tg737 levels in HCC specimens. Restoring Tg737 (without the 3’UTR) significantly hampered miR-548a-5p induced cell proliferation, and rescued the miR-548a-5p induced cell proliferation inhibition and apoptosis induced by cisplatin.

CONCLUSION: MiR-548a-5p negatively regulates the tumor inhibitor gene Tg737 and promotes tumorigenesis in vitro and in vivo, indicating its potential as a novel therapeutic target for HCC.

OncomiR or Tumor Suppressor? The Duplicity of MicroRNAs in Cancer

MicroRNAs (miRNA) are short, noncoding RNAs whose dysregulation has been implicated in most, if not all, cancers. They regulate gene expression by suppressing mRNA translation and reducing mRNA stability. To this end, there is a great deal of interest in modifying miRNA expression levels for the treatment of cancer. However, the literature is fraught with inconsistent accounts as to whether various miRNAs are oncogenic or tumor suppressive. In this review, we directly examine these inconsistencies and propose several mechanisms to explain them. These mechanisms include the possibility that specific miRNAs can simultaneously produce competing oncogenic and tumor suppressive effects by suppressing both tumor suppressive mRNAs and oncogenic mRNAs, respectively. In addition, miRNAs can modulate tumor-modifying extrinsic factors, such as cancer-immune system interactions, stromal cell interactions, oncoviruses, and sensitivity to therapy. Ultimately, it is the balance between these processes that determines whether a specific miRNA produces a net oncogenic or net tumor suppressive effect. A solid understanding of this phenomenon will likely prove valuable in evaluating miRNA targets for cancer therapy. Cancer Res; 76(13); 3666-70. ©2016 AACR.

Serum microRNA panels as potential biomarkers for early detection of hepatocellular carcinoma on top of HCV infection

The identification of new high-sensitivity and high-specificity markers for hepatocellular carcinoma (HCC) is essential. We aimed at identifying serum microRNAs (miRNAs) as potential biomarkers for early detection of HCC on top hepatitis C virus (HCV) infection. We investigated serum expression of 13 miRNAs in 384 patients with HCV-related chronic liver disease (192 with HCC, 96 with liver cirrhosis (LC), and 96 with chronic hepatitis C (CHC)) in addition to 96 healthy participants enrolled as a control group. The miRNA expression was performed using real-time quantitative PCR-based SYBR Green custom miRNA arrays. The area under the receiver operating characteristic curve (AUC) was used to evaluate the diagnostic performance of miRNA panels for early detection of HCC. Using miRNA panel of miR-122, miR-885-5p, and miR-29b with alpha fetoprotein (AFP) provided high diagnostic accuracy (AUC = 1) for early detection of HCC in normal population while using miRNA panel of miR-122, miR-885-5p, miR-221, and miR-22 with AFP provided high diagnostic accuracy (AUC = 0.982) for early detection of HCC in LC patients. However, using miRNA panel of miR-22 and miR-199a-3p with AFP provided high diagnostic accuracy (AUC = 0.988) for early detection of HCC in CHC patients. We identified serum miRNA panels that could have a considerable clinical use in early detection of HCC in both normal population and high-risk patients.

HCBP6 Modulates Triglyceride Homeostasis in Hepatocytes Via the SREBP1c/FASN Pathway

Hypertriglyceridemia leads to liver steatosis, cardiovascular disease, and type 2 diabetes. Although HCBP6 (hepatitis C virus core-binding protein 6) was previously shown to be an HCV (hepatitis C virus) core-binding protein, its biological function remains unclear. Here, we demonstrate that HCBP6 negatively regulates intracellular triglyceride (TG) levels in hepatocytes. We found that bidirectional manipulation of hepatocyte HCBP6 expression by knockdown or overexpression results in increased or decreased TG accumulation, respectively. In addition, HCBP6 mRNA and protein levels exhibited significant time- and dose-dependent increases in a cellular model of lipid-overload hepatic steatosis. Furthermore, TG levels are regulated by HCBP6-sterol regulatory element binding protein 1c (SREBP1c)-mediated fatty acid synthase (FASN) expression. We also demonstrate that HCBP6 mRNA and protein expression is inhibited by microRNA-122 (miR-122), and miR-122 overexpression elicited more robust translational repression of luciferase activity driven by the full 3'-UTR of HCBP6. Taken together, our results provide new evidence that miR-122-regulated HCBP6 functions as a sensor protein to maintain intrahepatocyte TG levels.

Cross Talk between Cancer and Mesenchymal Stem Cells through Extracellular Vesicles Carrying Nucleic Acids

Extracellular vesicles (EVs) are considered to be a novel complex mechanism of cell communication within the tumor microenvironment. EVs may act as vehicles for transcription factors and nucleic acids inducing epigenetic changes in recipient cells. Since tumor EVs may be present in patient biological fluids, it is important to investigate their function and molecular mechanisms of action. It has been shown that tumor cells release EVs, which are capable of regulating cell apoptosis, proliferation, invasion, and epithelial-mesenchymal transition, as well as to suppress activity of immune cells, to enhance angiogenesis, and to prepare a favorable microenvironment for metastasis. On the other hand, EVs derived from stromal cells, such as mesenchymal stem cells (MSCs), may influence the phenotype of tumor cells through reciprocal cross talk greatly influenced by the transcription factors and nucleic acids they carry. In particular, non-coding RNAs (ncRNAs), including microRNAs and long ncRNAs, have recently been identified as the main candidates for the phenotypic changes induced in the recipient cells by EVs. ncRNAs, which are important regulators of mRNA and protein expression, can function either as tumor suppressors or as oncogenes, depending on their targets. Herein, we have attempted to revise actual evidence reported in the literature on the role of EVs in tumor biology with particular regard to the cross talk of ncRNAs between cancer cells and MSCs.

Molecular pathogenesis of hepatocellular carcinoma and impact of therapeutic advances

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality and has an increasing incidence worldwide. HCC can be induced by multiple etiologies, is influenced by many risk factors, and has a complex pathogenesis. Furthermore, HCCs exhibit substantial heterogeneity, which compounds the difficulties in developing effective therapies against this highly lethal cancer. With advances in cancer biology and molecular and genetic profiling, a number of different mechanisms involved in the development and progression of HCC have been identified. Despite the advances in this area, the molecular pathogenesis of hepatocellular carcinoma is still not completely understood. This review aims to elaborate our current understanding of the most relevant genetic alterations and molecular pathways involved in the development and progression of HCC, and anticipate the potential impact of future advances on therapeutic drug development.

MiR-122 Reverses the Doxorubicin-Resistance in Hepatocellular Carcinoma Cells through Regulating the Tumor Metabolism

Doxorubicin (DOX) is one of the most commonly used anticancer drugs in the treatment of hepatoma. However, acquired drug resistance is one of the major challenges for the chemotherapy. In this study, a down-regulation of miR-122 was observed in doxorubicin-resistant Huh7 (Huh7/R) cells compared with its parental Huh7 cells, suggesting miR-122 is associated with the chemoresistance. Meanwhile, luciferase reporter assay proved that the PKM2 is the target of miR-122, and we reported that the glucose metabolism is significantly up-regulated in Huh7/R cells. Importantly, overexpression of miR-122 in Huh7/R cells reversed the doxorubicin-resistance through the inhibition of PKM2, inducing the apoptosis in doxorubicin-resistant cancer cells. Thus, this study revealed that the dysregulated glucose metabolism contributes to doxorubicin resistance, and the inhibition of glycolysis induced by miR-122 might be a promising therapeutic strategy to overcome doxorubicin resistance in hepatocellular carcinoma.