Methylation-regulated miR-124-1 suppresses tumorigenesis in hepatocellular carcinoma by targeting CASC3

The Epigenetic Role of miR-124 in HIV-1 Tat- and Cocaine-Mediated Microglial Activation

HIV-1 and drug abuse have been indissolubly allied as entwined epidemics. It is well-known that drug abuse can hasten the progression of HIV-1 and its consequences, especially in the brain, causing neuroinflammation. This study reports the combined effects of HIV-1 Transactivator of Transcription (Tat) protein and cocaine on miR-124 promoter DNA methylation and its role in microglial activation and neuroinflammation. The exposure of mouse primary microglial cells to HIV-1 Tat (25 ng/mL) and/or cocaine (10 μM) resulted in the significantly decreased expression of primary (pri)-miR-124-1, pri-miR-124-2, and mature miR-124 with a concomitant upregulation in DNMT1 expression as well as global DNA methylation. Our bisulfite-converted genomic DNA sequencing also revealed significant promoter DNA methylation in the pri-miR-124-1 and pri-miR-124-2 in HIV-1 Tat- and cocaine-exposed mouse primary microglial cells. We also found the increased expression of proinflammatory cytokines such as IL1β, IL6 and TNF in the mouse primary microglia exposed to HIV-1 Tat and cocaine correlated with microglial activation. Overall, our findings demonstrate that the exposure of mouse primary microglia to both HIV-1 Tat and cocaine could result in intensified microglial activation via the promoter DNA hypermethylation of miR-124, leading to the exacerbated release of proinflammatory cytokines, ultimately culminating in neuroinflammation.

Changes in miR-124-1, miR-212, miR-132, miR-134, and miR-155 Expression Patterns after 7,12-Dimethylbenz(a)anthracene Treatment in CBA/Ca Mice

Specific gene and miRNA expression patterns are potential early biomarkers of harmful environmental carcinogen exposures. The aim of our research was to develop an assay panel by using several miRNAs for the rapid screening of potential carcinogens. The expression changes of miR-124-1, miR-212, miR-132, miR-134, and miR-155 were examined in the spleen, liver, and kidneys of CBA/Ca mice, following the 20 mg/bwkg intraperitoneal 7,12-dimethylbenz(a)anthracene (DMBA) treatment. After 24 h RNA was isolated, the miRNA expressions were analyzed by a real-time polymerase chain reaction and compared to a non-treated control. DMBA induced significant changes in the expression of miR-134, miR-132, and miR-124-1 in all examined organs in female mice. Thus, miR-134, miR-132, and miR-124-1 were found to be suitable biomarkers for the rapid screening of potential chemical carcinogens and presumably to monitor the protective effects of chemopreventive agents.

Tumor Suppressive Effects of miR-124 and Its Function in Neuronal Development

MicroRNA-124 (miR-124) is strongly expressed in neurons, and its expression increases as neurons mature. Through DNA methylation in the miR-124 promoter region and adsorption of miR-124 by non-coding RNAs, miR-124 expression is known to be reduced in many cancer cells, especially with high malignancy. Recently, numerous studies have focused on miR-124 due to its promising tumor-suppressive effects; however, the overview of their results is unclear. We surveyed the tumor-suppressive effect of miR-124 in glial cell lineage cancers, which are the most frequently reported cancer types involving miR-124, and in lung, colon, liver, stomach, and breast cancers, which are the top five causes of cancer death. Reportedly, miR-124 not only inhibits proliferation and accelerates apoptosis, but also comprehensively suppresses tumor malignant transformation. Moreover, we found that miR-124 exerts its anti-tumor effects by regulating a wide range of target genes, most notably STAT3 and EZH2. In addition, when compared to the original role of miR-124 in neuronal development, we found that the miR-124 target genes that contribute to neuronal maturation share similarities with genes that cause cancer cell metastasis and epithelial-mesenchymal transition. We believe that the two apparently unrelated fields, cancer and neuronal development, can bring new discoveries to each other through the study of miR-124.

miR-660 promotes liver cancer cell proliferation by targeting PPP2R2A

Liver cancer (LC) is the leading cause for tumor-related death worldwide, and microRNAs (miRs) have been demonstrated to regulate the progression of LC. In the current study, the function of miR-660 in LC cells was investigated, and the results indicated that miR-660 was highly expressed in LC tissues and cells. This increased expression promoted LC cell proliferation and increased the percentage of S phase cells, while miR-660 knockdown inhibited cell proliferation and increased the percentage of G₀/G₁ phase cells. A Ser/Thr phosphatase protein phosphatase 2 regulatory subunit βα (PPP2R2A) was indicated as the target of miR-660, and miR-660 could inhibit PPP2R2A levels. The luciferase reporter assay suggested that miR-660 directly bound to the 3'-untranslated region of PPP2R2A. Additionally, it was revealed that miR-660 inhibited p21 expression and promoted cyclin D1 expression, confirming that miR-660 regulated LC cell proliferation by regulating cell cycle progression. The double knockdown of miR-660 and PPP2R2A promoted LC cell proliferation, suggesting that miR-660 promoted LC proliferation by targeting PPP2R2A.

The construction and validation of an RNA binding protein-related prognostic model for bladder cancer

Background

RNA-binding proteins (RBPs) play crucial and multifaceted roles in post-transcriptional regulation. While RBPs dysregulation is involved in tumorigenesis and progression, little is known about the role of RBPs in bladder cancer (BLCA) prognosis. This study aimed to establish a prognostic model based on the prognosis-related RBPs to predict the survival of BLCA patients.

Methods

We downloaded BLCA RNA sequence data from The Cancer Genome Atlas (TCGA) database and identified RBPs differentially expressed between tumour and normal tissues. Then, functional enrichment analysis of these differentially expressed RBPs was conducted. Independent prognosis-associated RBPs were identified by univariable and multivariable Cox regression analyses to construct a risk score model. Subsequently, Kaplan–Meier and receiver operating characteristic curves were plotted to assess the performance of this prognostic model. Finally, a nomogram was established followed by the validation of its prognostic value and expression of the hub RBPs.

Results

The 385 differentially expressed RBPs were identified included 218 and 167 upregulated and downregulated RBPs, respectively. The eight independent prognosis-associated RBPs (EFTUD2, GEMIN7, OAS1, APOBEC3H, TRIM71, DARS2, YTHDC1, and RBMS3) were then used to construct a prognostic prediction model. An in-depth analysis showed lower overall survival (OS) in patients in the high-risk subgroup compared to that in patients in the low-risk subgroup according to the prognostic model. The area under the curve of the time-dependent receiver operator characteristic (ROC) curve were 0.795 and 0.669 for the TCGA training and test datasets, respectively, showing a moderate predictive discrimination of the prognostic model. A nomogram was established, which showed a favourable predictive value for the prognosis of BLCA.

Conclusions

We developed and validated the performance of a prognostic model for BLCA that might facilitate the development of new biomarkers for the prognostic assessment of BLCA patients.

Circular RNA circ_0091579 Promotes Hepatocellular Carcinoma Proliferation, Migration, Invasion, and Glycolysis Through miR-490-5p/CASC3 Axis

Background: Hepatocellular carcinoma (HCC) is one of the most common malignancies with high invasion and metastasis capacities. Circular RNAs (circRNAs) were evidenced to take part in the progression of multifarious cancers, including HCC. However, the role of circ_0091579 in HCC progression has not been fully described. This study aimed to explore the function of circ_0091579 and its potential regulatory mechanism in the progression of HCC. Materials and Methods: The expression of circ_0091579, microRNA-490-5p (miR-490-5p), and cancer susceptibility candidate 3 (CASC3) in HCC tissues and cells was detected by quantitative real-time polymerase chain reaction. The circular characteristic and stability of circ_0091579 were verified by RNase R digestion and actinomycin D reaction assays. Cell proliferation, migration, and invasion were determined by methyl thiazolyl tetrazolium assay and Transwell assay, respectively. The level of glycolysis was evaluated by glucose consumption and lactate production. The levels of proteins were examined by Western blot. The interaction between miR-490-5p and circ_0091579 or CASC3 was certified by Dual-luciferase reporter assay. Results: circ_0091579 and CASC3 were upregulated, while miR-490-5p was downregulated in HCC tissues and cells. Silencing of either circ_0091579 or CASC3 suppressed cell proliferation, migration, invasion, and glycolysis in HCC cells. Moreover, miR-490-5p was verified to directly bind to circ_0091579 and CASC3. Circ_0091579 upregulated CASC3 by sponging miR-490-5p in HCC cells to promote cell proliferation, invasion, and migration. Conclusion: circ_0091579 promoted cell proliferation, migration, invasion, and glycolysis partially through miR-490-5p/CASC3 axis in HCC cells.

Expression and gene regulation network of RBM8A in hepatocellular carcinoma based on data mining

RNA binding motif protein 8A (RBM8A) is an RNA binding protein in a core component of the exon junction complex. Abnormal RBM8A expression is associated with carcinogenesis. We used sequencing data from the Cancer Genome Atlas database and Gene Expression Omnibus, analyzed RBM8A expression and gene regulation networks in hepatocellular carcinoma (HCC). Expression was analyzed using Oncomine^TM and Gene Expression Profiling Interactive Analysis tools, while RBM8A alterations and related functional networks were identified using cBioPortal. LinkedOmics was used to identify differential gene expression with RBM8A and to analyze Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. Gene enrichment analysis examined target networks of kinases, miRNAs and transcription factors. We found that RBM8A is overexpressed and the RBM8A gene often amplified in HCC. Expression of this gene is linked to functional networks involving the ribosome and RNA metabolic signaling pathways. Functional network analysis suggested that RBM8A regulates the spliceosome, ribosome, DNA replication and cell cycle signaling via pathways involving several cancer-related kinases, miRNAs and E2F Transcription Factor 1. Our results demonstrate that data mining efficiently reveals information about RBM8A expression and potential regulatory networks in HCC, laying a foundation for further study of the role of RBM8A in carcinogenesis.

Comprehensive analysis of biological networks and the eukaryotic initiation factor 4A-3 gene as pivotal in hepatocellular carcinoma

Eukaryotic initiation factor 4A-3 (EIF4A3) is a core component of the exon junction complex (EJC). Abnormalities in EIF4A3 are associated with carcinogenesis. The present study aimed to determine the biological role of EIF4A3 in hepatocellular carcinoma (HCC). Our study is based on the analysis of HCC sequencing data from public databases. We first used the Gene Expression Profiling Interactive Analysis tool and ONCOMINE to analyze the EIF4A3 expression, and the results were validated in human clinical tissues by a quantitative real-time polymerase chain reaction, Western blot, and immunohistochemical. Then, we used cBioPortal to identify EIF4A3 alterations and function networks. Finally, we created a network of genes that were positively correlated with EIF4A3 using LinkedOmics, and analyzed this network using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. For the genes identified, we also analyzed the relevant kinase and transcription factor target networks as well as the protein-protein interaction networks. Our results show that EIF4A3 was overexpressed in HCC tissues in comparison with normal tissues, and high EIF4A3 expression was significantly associated with poor prognosis. Analysis of the functional networks of genes that were co-occurring with EIF4A3 amplification revealed connections with several chemokine signaling pathways. Furthermore, genes that positively correlated with EIF4A3 were mainly related to cell cycle and spliceosome pathways, several cell cycle regulatory kinases, and tumor-associated transcription factors. Finally, crosslinking-immunoprecipitation and high-throughput sequencing (CLIP-seq) data showed that EIF4A3 protein binds to multiple exon regions of the cell cycle regulatory genes cyclin-dependent kinases 1 and 2 and transcription factor E2F1. Our study unveils potential biological networks in HCC and the pivotal role of EIF4A3 as a bridging protein, highlighting the need for an in-depth study of EIF4A3 in carcinogenesis.

The circular RNA HIPK3 (circHIPK3) and its regulation in cancer progression: Review

Circular RNAs (circRNAs) are a class of covalently closed continuous loops of single-stranded RNA molecules, and broadly expressed in the cytoplasm of eukaryotic cells. CircRNAs have attracted considerable research attention in recent years, an attention primarily attributed to their critical roles in the development and progression of diseases, especially in cancers. The circRNA homeodomain-interacting protein kinase 3 (circHIPK3) is a recently identified circRNA, acknowledged to be relevant to human pathology and cancer progression. Here, we summarize the origin and functions of the circHIPK3 and its target molecules in cancer, and thus, providing a broader knowledge to our current understanding of circRNAs. This review will therefore be essential to enriching our knowledge on the roles of circRNAs in cancers by outlining their potential values and application in the diagnosis and treatment of cancer.

Role of MicroRNA-124 as a Prognostic Factor in Multiple Neoplasms: A Meta-Analysis

Objective

MicroRNA-124 (miR-124) was revealed to be an attractive prognostic tumour biomarker in recent studies. However, the results remain inconclusive. Hence, this meta-analysis was carried out to clarify the precise predictive value of miR-124.

Materials and Methods

Relevant studies were searched in PubMed, EMBASE, Web of Science, and the Cochrane Library up to October 2018. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were extracted from the selected studies.

Results

A total of 29 articles investigating the correlation between miR-124 expression and prognosis were initially identified. The pooled HR for overall survival (OS) of high miR-124 expression in multiple cancers was 0.55 (95%CI = 0.50–0.61). Disease-free survival (DFS)/progression-free survival (HR = 0.48, 95%CI = 0.38–0.61) revealed a protective role of increased miR-124 expression. Epigenetic hypermethylation of miR-124 mediated the silencing of its expression, which is correlated significantly with unfavourable survival (OS: HR = 2.06, 95%CI = 1.68–2.53; DFS/recurrence-free survival: HR = 2.77, 95%CI = 1.85–4.16).

Conclusions

Taken together, our results suggest that miR-124 plays an antioncogenic role in various tumors, such as lung cancer and colorectal cancer. If methylation of miR-124 could be prevented, progression and metastasis would be improved; thus, miR-124 may be a promising biomarker and novel therapeutic target. Further large-scale studies are needed to confirm this possible effect.

MicroRNA-124: An emerging therapeutic target in cancer

MicroRNAs (miRNAs) are noncoding single‐stranded RNAs, approximately 20‐24 nucleotides in length, known as powerful posttranscriptional regulators. miRNAs play important regulatory roles in cellular processes by changing messenger RNA expression and are widely involved in human diseases, including tumors. It has been reported in the literature that miRNAs have a precise role in cell proliferation, programmed cell death, differentiation, and expression of coding genes. MicroRNA‐124 (miR‐124) has reduced exparession in various human neoplasms and is believed to be related to the occurrence, development, and prognosis of malignant tumors. In our review, we focus on the specific molecular functions of miR‐124 and the downstream gene targets in major cancers, which provide preclinical evidence for the treatment of human cancer. Although some obstacles exist, miR‐124 is still attracting intensive research focus as a promising and effective anticancer weapon.

Interaction of transforming growth factor-β-Smads/microRNA-362-3p/CD82 mediated by M2 macrophages promotes the process of epithelial-mesenchymal transition in hepatocellular carcinoma cells

Abnormal tumor microenvironment and the epithelial‐mesenchymal transition (EMT) are important features of tumor metastasis. However, it remains unknown how signals can form complicated networks to regulate the sustainability of the EMT process. The aim of our study is to explore the possible interaction between tumor‐associated macrophages and tumor cells in the EMT process mediated by microRNA (miR)‐362‐3p. In this study, we found that by releasing TGF‐β, M2 macrophages mediate binding of Smad2/3 to miR‐362‐3p promoter, leading to overexpression of miR‐362‐3p. MicroRNA‐362‐3p maintains EMT by regulating CD82, one of the most important members of the family of tetraspanins. Our finding suggests that miR‐362‐3p can serve as a core factor mediating cross‐talk between the TGF‐β pathway in tumor‐associated macrophages and tetraspanins in tumor cells, and thus facilitates the EMT process.

Regulatory Network of Two Tumor-Suppressive Noncoding RNAs Interferes with the Growth and Metastasis of Renal Cell Carcinoma

Noncoding RNAs (ncRNAs) such as microRNAs (miRNAs) and long ncRNAs (lncRNAs) have been shown to function as pivotal regulators in the carcinogenesis of renal cell carcinoma (RCC). However, the functions and underlying mechanisms of most ncRNAs in RCC are still elusive, and the crosstalks of different layers of ncRNAs are seldom reported. Here we showed that miR-124 and maternally expressed gene 3 (MEG3) were both significantly reduced in RCC, and combined expression of miR-124 and MEG3 emerged as an independent prognostic factor in our RCC cohort. Overexpression of miR-124 or MEG3 inhibited cell proliferation, migration, and invasion in vitro, and restrained tumor growth in vivo. EZH2 knockdown induced the epigenetic silencing of miR-124 and MEG3 expression by H3K27me3. Besides, miR-124 directly targeted the TET1 transcript, and then the interaction resulted in the upregulation of MEG3. Furthermore, we demonstrated that MEG3 induced p53 protein accumulation, whereas p53 was a positive transcriptional regulator of the miR-124. In addition, tumor-suppressive PTPN11 was identified as a direct target of miR-124, as well as the MEG3- and p53-regulated gene. Our study identifies three crosstalks between miR-124 and MEG3, which provide a plausible link for these two ncRNAs in RCC. Both ncRNAs exert important antitumor effects in RCC pathogenesis and might serve as prognostic biomarkers and molecular therapeutic targets.

Interaction of lncRNA-MALAT1 and miR-124 regulates HBx-induced cancer stem cell properties in HepG2 through PI3K/Akt signaling

BACKGROUND

Hepatitis B virus X protein (HBx) plays a crucial role in initiating and promoting HBV-induced hepatocellular carcinoma (HCC) development. Reports indicated that HBx promotes cancer stem cell (CSC) generation, which may be associated with HBV-related HCC. Noncoding RNA miR-124 and long noncoding RNA (lncRNA)-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) were considered to be involved deeply in the progress of HBx-related HCC. Hence, the underlying mechanism of miR-124 and lncRNA-MALAT1 in regulating HBx-promoted CSC needs to be studied.

MATERIALS AND METHODS

In present study, HepG2-X cell line was induced by transfect HBx into HepG2 cells. Overexpressing of miR-124 or silencing of lncRNA-MALAT1 was completed by transfecting miR-124 mimic or shMALAT1 into HepG2-X cells. HBx-induced CSC properties and tumorigenic potential of HepG2 cells were determined by detecting CSC marker expression, colony formation assay, and xenograft tumorigenesis. The mechanism of HBx-induced CSC properties was explored by PI3K/Akt inhibitor. Interaction of miR-124 and lncRNA-MALAT1 was detected by luciferase reporter assay.

RESULTS

HBx promoted CSC properties through upregulating stemness markers and reprogramming proteins, and contributed to tumorigenicity of HepG2-X cells both in vivo and in vitro. Inhibition of Akt activation blocked the HBx-stimulated reprogramming proteins and stemness markers. HBx upregulated lncRNA-MALAT1 expression while downregulating miR-124 expression in HepG2-X cells. miR-124 interacts with lncRNA-MALAT1 by direct targeting. Overexpression of miR-124 or silencing of lncRNA-MALAT1 both blocked HBx-induced CSC generation, stemness-related factor activation and tumorigenicity via PI3K/Akt signaling.

CONCLUSION

Our results demonstrated that miR-124 interact with lncRNA-MALAT1 and involve in regulating HBx-induced CSC properties via PI3K/Akt signaling.

Identification of microRNA-124 in regulation of Hepatocellular carcinoma through BIRC3 and the NF-κB pathway

MicroRNAs (miRNAs) being proved to be involved in the carcinogenesis of numerous tumors. MicroRNA-124 (miR-124), identified as a tumor suppressor, has been demonstrated to exert pivotal roles in multiple processes of tumorigenesis. The present study demonstrated that miR-124 was low-expressed in human hepatocellular carcinoma (HCC) tissues and cell lines. In addition, overexpression of miR-124 through infected with miR-124 lentivirus inhibited the proliferation and migration of HCC in vitro and tumorigenesis in vivo, whereas inhibition of miR-124 expression can reverse the process. Moreover, Baculoviral IAP Repeat Containing 3 (BIRC3) was identified as a target gene of miR-124. The BIRC3 mRNA expression was increased in HCC tissues and negatively correlated with miR-124 expression. Knockdown of BIRC3 recovered the miR-124-induced inhibiting effect on HCC progression. Furthermore, we found that up-regulation of miR-124 significantly inhibited p-P65, p-IκBα and c-Myc proteins expression. However, the effect of miR-124 up-regulation on HCC development was partly reversed by BIRC3 restoration. In conclusion, our data proved that miR-124 inhibits the proliferation and migration of HCC at least partly through targeting BIRC3 and regulating NF-κB signaling pathway, and it may be a therapeutic target for HCC prognosis.

Involvement of anti-tumor miR-124-3p and its targets in the pathogenesis of pancreatic ductal adenocarcinoma: direct regulation of ITGA3 and ITGB1 by miR-124-3p

MicroRNAs (miRNAs) are unique in that a single miRNA molecule regulates a vast number of RNA transcripts. Thus, aberrantly expressed miRNAs disrupt tightly controlled RNA networks in cancer cells. Our functional screening showed that expression of miR-124-3p was downregulated in pancreatic ductal adenocarcinoma (PDAC) tissues. Here, we aimed to investigate the anti-tumor roles of miR-124-3p in PDAC cells and to identify miR-124-3p-mediated oncogenic signaling in this disease. Ectopic expression of miR-124-3p inhibited cancer cell migration and invasion in PDAC cells. Moreover, restoration of miR-124-3p suppressed oncogenic signaling, as demonstrated by reduced phosphorylation of focal adhesion kinase, AKT, and extracellular signal-regulated kinase, in PDAC cells. Our in silico database analyses and luciferase reporter assays showed that two cell-surface matrix receptors, integrin α3 (ITGA3) and integrin β1 (ITGB1), were directly regulated by miR-124-3p in PDAC cells. Overexpression of ITGA3 and ITGB1 was confirmed in PDAC clinical specimens. Interestingly, a large number of cohort analyses from TCGA database showed that high expressions of ITGA3 and ITGB1 were significantly associated with poor prognosis of patients with PDAC. Knockdown of ITGA3 and ITGB1 by siRNAs markedly suppressed the migration and invasion abilities of PDAC cells. Moreover, downstream oncogenic signaling was inhibited by ectopic expression of miR-124-3p or knockdown of the two integrins. The discovery of anti-tumor miRNAs and miRNA-mediated oncogenic signaling may provide novel therapeutic targets for the treatment of PDAC.

Epigenetic Promoter DNA Methylation of miR-124 Promotes HIV-1 Tat-Mediated Microglial Activation via MECP2-STAT3 Axis

The present study demonstrates HIV-1 Tat-mediated epigenetic downregulation of microglial miR-124 and its association with microglial activation. Exposure of mouse primary microglia isolated from newborn pups of either sex to HIV-1 Tat resulted in decreased expression of primary miR-124-1, primary miR-124-2 as well as the mature miR-124. In parallel, HIV-1 Tat exposure to mouse primary microglial cells resulted in increased expression of DNA methylation enzymes, such as DNMT1, DNMT3A, and DNMT3B, which were also accompanied by increased global DNA methylation. Bisulfite-converted genomic DNA sequencing in the HIV-1 Tat-exposed mouse primary microglial cells further confirmed increased DNA methylation of the primary miR-124-1 and primary miR-124-2 promoters. Bioinformatic analyses identified MECP2 as a novel 3'-UTR target of miR-124. This was further validated in mouse primary microglial cells wherein HIV-1 Tat-mediated downregulation of miR-124 resulted in increased expression of MECP2, leading in turn to further repression of miR-124 via the feedback loop. In addition to MECP2, miR-124 also modulated the levels of STAT3 through its binding to the 3'-UTR, leading to microglial activation. Luciferase assays and Ago2 immunoprecipitation determined the direct binding between miR-124 and 3'-UTR of both MECP2 and STAT3. Gene silencing of MECP2 and DNMT1 and overexpression of miR-124 blocked HIV-1 Tat-mediated downregulation of miR-124 and microglial activation. In vitro findings were also confirmed in the basal ganglia of SIV-infected rhesus macaques (both sexes). In summary, our findings demonstrate a novel mechanism of HIV-1 Tat-mediated activation of microglia via downregulation of miR-124, leading ultimately to increased MECP2 and STAT3 signaling.SIGNIFICANCE STATEMENT Despite the effectiveness of combination antiretroviral therapy in controlling viremia, the CNS continues to harbor viral reservoirs. The persistence of low-level virus replication leads to the accumulation of early viral proteins, including HIV-1 Tat protein. Understanding the epigenetic/molecular mechanism(s) by which viral proteins, such as HIV-1 Tat, can activate microglia is thus of paramount importance. This study demonstrated that HIV-1 Tat-mediated DNA methylation of the miR-124 promoter leads to its downregulation with a concomitant upregulation of the MECP2-STAT3-IL6, resulting in microglial activation. These findings reveal an unexplored epigenetic/molecular mechanism(s) underlying HIV-1 Tat-mediated microglial activation, thereby providing a potential target for the development of therapeutics aimed at ameliorating microglial activation and neuroinflammation in the context of HIV-1 infection.

Methyl jasmonate leads to necrosis and apoptosis in hepatocellular carcinoma cells via inhibition of glycolysis and represses tumor growth in mice

Methyl jasmonate has recently been found to have anti-cancer activity. Methyl jasmonate detached hexokinase 2 from a voltage dependent anion channel causing a reduction in mitochondrial transmembrane potential that led to the release of cytochrome C and apoptosis inducing factor resulting in intrinsic apoptosis. Blocked adenosine triphosphate synthesis caused by mitochondrial injury hampered oxidative phosphorylation and led to cell necrosis. The results were applied to the in vivo treatment of nude mice with a satisfactory effect. Collectively, our results suggest that methyl jasmonate may be an adjuvant therapy for liver tumors due to its mechanism in cancer cells compared to that in normal cells: The major function is to inhibit glycolysis instead of changing aerobic metabolism.

Hypermethylation of NF-κB-Activating Protein-Like (NKAPL) Promoter in Hepatocellular Carcinoma Suppresses Its Expression and Predicts a Poor Prognosis

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is a complicated disease with low survival rate partially due to frequent recurrence and no efficient therapy. Promoter hypermethylation of tumor suppressor genes has been demonstrated as one of the molecular mechanisms contributing to tumorigenesis and progression in HCC. This study aims to investigate regulation of NKAPL expression by promoter methylation and its clinical relevance as a biomarker for HCC.

METHODS

We measured mRNA expression of NKAPL in 5 HCC cell lines and a cohort of 62 pairs of primary HCC tumor and their adjacent non-cancer liver tissues. NKAPL protein expression on HCC cell lines and clinical samples was assessed by Western blot and immunohistochemistry, respectively. Association analyses between NKAPL expression and clinicopathologic characteristics in the cohort were conducted. Methylation statuses of NKAPL promoter in 18 pairs of tumor and adjacent non-tumor HCC samples were studied using methylation-specific PCR. Biological functions of NKAPL in HCC were investigated by ectopic expression of NKAPL in HCC cells, and cell viability and cell cycle analyses were performed.

RESULTS

Our present study showed suppressed expression and promoter hypermethylation are common events in HCC. Demethylation experiment in HCC cells demonstrated that the NKAPL expression was regulated by promoter methylation. In addition, high methylation level of NKAPL and its low expression predict poor outcome. Furthermore, ectopic expression of NKAPL in the HCC cells inhibited cell growth.

CONCLUSIONS

Our findings suggest that methylation of NKAPL is a frequent event and is a potential prognosis biomarker in HCC.

MicroRNA-124-3p expression and its prospective functional pathways in hepatocellular carcinoma: A quantitative polymerase chain reaction, gene expression omnibus and bioinformatics study

The present study aimed to explore the potential clinical significance of microRNA (miR)-124-3p expression in the hepatocarcinogenesis and development of hepatocellular carcinoma (HCC), as well as the potential target genes of functional HCC pathways. Reverse transcription-quantitative polymerase chain reaction was performed to evaluate the expression of miR-124-3p in 101 HCC and adjacent non-cancerous tissue samples. Additionally, the association between miR-124-3p expression and clinical parameters was also analyzed. Differentially expressed genes identified following miR-124-3p transfection, the prospective target genes predicted in silico and the key genes of HCC obtained from Natural Language Processing (NLP) were integrated to obtain potential target genes of miR-124-3p in HCC. Relevant signaling pathways were assessed with protein-protein interaction (PPI) networks, Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Protein Annotation Through Evolutionary Relationships (PANTHER) pathway enrichment analysis. miR-124-3p expression was significantly reduced in HCC tissues compared with expression in adjacent non-cancerous liver tissues. In HCC, miR-124-3p was demonstrated to be associated with clinical stage. The mean survival time of the low miR-124-3p expression group was reduced compared with that of the high expression group. A total of 132 genes overlapped from differentially expressed genes, miR-124-3p predicted target genes and NLP identified genes. PPI network construction revealed a total of 109 nodes and 386 edges, and 20 key genes were identified. The major enriched terms of three GO categories included regulation of cell proliferation, positive regulation of cellular biosynthetic processes, cell leading edge, cytosol and cell projection, protein kinase activity, transcription activator activity and enzyme binding. KEGG analysis revealed pancreatic cancer, prostate cancer and non-small cell lung cancer as the top three terms. Angiogenesis, the endothelial growth factor receptor signaling pathway and the fibroblast growth factor signaling pathway were identified as the most significant terms in the PANTHER pathway analysis. The present study confirmed that miR-124-3p acts as a tumor suppressor in HCC. miR-124-3p may target multiple genes, exerting its effect spatiotemporally, or in combination with a diverse range of processes in HCC. Functional characterization of miR-124-3p targets will offer novel insight into the molecular changes that occur in HCC progression.

circHIPK3 regulates cell proliferation and migration by sponging miR-124 and regulating AQP3 expression in hepatocellular carcinoma

Noncoding RNAs plays an important role in hepatocellular carcinoma (HCC). Here, we show that miR-124 was downregulated in HCC tissues and that the ectopic expression of miR-124 inhibited the proliferation and migration of HCC cells. We proposed that aquaporin 3 (AQP3) is a direct target of miR-124. AQP3 was upregulated in HCC tissues and inversely correlated with miR-124 expression. The overexpression of miR-124 decreased AQP3 expression. Indeed, AQP3 overexpression promoted cell proliferation and migration, whereas miR-124 knockdown suppressed cell proliferation and migration. Furthermore, we found that circular RNA HIPK3 (circHIPK3) acted as a miR-124 sponge and regulated the expression of the miR-124 target gene AQP3. circHIPK3 was upregulated in HCC tissues and positively correlated with AQP3 expression. Thus, silencing circHIPK3 inhibited cell proliferation and migration by downregulating AQP3 expression. Moreover, miR-124 inhibition rescued circHIPK3 knockdown induced reduction in cell proliferation and migration, as well as AQP3 expression. In vivo experiments also confirmed that circHIPK3 regulated xenograft tumor growth via the miR-124-AQP3 axis. These observations indicate a possible novel therapeutic strategy involving circular RNAs in HCC.

Salidroside ameliorates autophagy and activation of hepatic stellate cells in mice via NF-κB and TGF-β1/Smad3 pathways

PURPOSE

Liver fibrosis is commonly seen and a necessary stage in chronic liver disease. The aim of this study was to explore the effect of salidroside on liver fibrosis in mice and its potential mechanisms.

MATERIALS AND METHODS

Two mouse liver fibrosis models were established by intraperitoneal injection of carbon tetrachloride (CCl₄) for 8 weeks and bile duct ligation for 14 days. Salidroside was injected intraperitoneally at doses of 10 and 20 mg/kg once a day. Gene and protein expression levels were determined by quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, Western blot, immunohistochemistry, and immunofluorescence.

RESULTS

Salidroside inhibited the production of extracellular matrix (ECM) and regulated the balance between MMP2 and TIMP1 and, therefore, alleviated liver fibrosis in the two fibrosis models. Salidroside reduced the production of transforming growth factor (TGF)-β1 in Kupffer cells and hepatic stellate cells (HSCs) via the nuclear factor-κB signaling pathway and, therefore, inhibited the activation of HSCs and autophagy by downregulation of the TGF-β1/Smad3 signaling pathway.

CONCLUSION

Salidroside can effectively attenuate liver fibrosis by inhibiting the activation of HSCs in mice.

Clinical value of urinary retinol-binding protein in ascites due to cirrhosis

The aim of the present study was to explore the clinical value of urinary retinol-binding protein (RBP) level in the prognosis of cirrhotic ascites by assessment of the RBP levels prior to and following ascites treatment. The levels of urinary RBP, urinary microalbumin (mAlb), serum urea nitrogen (urea) and serum creatinine (Cr), and the estimated glomerular filtration rate (eGFR) were measured in 90 patients with cirrhosis and ascites hospitalized in a single institution between May 2011 and January 2012, and in 30 healthy controls. The levels of urinary mAlb, serum urea and serum Cr were higher in the cirrhotic patients compared with the healthy controls (P<0.05). Urinary RBP levels were significantly higher and eGFR was significantly lower in the liver cirrhosis group compared with the healthy control group (P<0.01). Urinary RBP, urinary mAlb, serum urea and serum Cr increased and eGFR decreased as the severity of the ascites increased (P<0.05). Urinary RBP was significantly higher in patients whose ascites did not respond or was refractory compared with those in whom it subsided (P<0.05), exhibiting a gradual increase over time in the former and a gradual reduction over time in the latter group (P<0.05). Increased urinary RBP and decreased eGFR in the early stage of cirrhosis ascites suggested impaired renal function, which serves a role in the process of ascites formation. These results indicated that urinary RBP is a sensitive indicator of early renal injury in patients with ascites due to cirrhosis and is closely associated with the progression of cirrhotic ascites.

By inhibiting PFKFB3, aspirin overcomes sorafenib resistance in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the few cancers with a continuous increase in incidence and mortality. Drug resistance is a major problem in the treatment of HCC. In this study, two sorafenib-resistant HCC cell lines and a nude mouse subcutaneously tumor model were used to explore the possible mechanisms leading to sorafenib resistance, and to investigate whether aspirin could increase the sensitivity of hepatoma cells to sorafenib. The combination of aspirin and sorafenib resulted in a synergistic antitumor effect against liver tumors both in vitro and in vivo. High glycolysis and PFKFB3 overexpression occupied a dominant position in sorafenib resistance, and can be targeted and overcome by aspirin. Aspirin plus sorafenib induced apoptosis in tumors without inducing weight loss, hepatotoxicity or inflammation. Our results suggest that aspirin overcomes sorafenib resistance and their combination may be an effective treatment approach for HCC.

Prognostic value of microRNAs in hepatocellular carcinoma: a meta-analysis

Background

Numerous articles reported that dysregulated expression levels of miRNAs correlated with survival time of HCC patients. However, there has not been a comprehensive meta-analysis to evaluate the accurate prognostic value of miRNAs in HCC.

Design

Meta-analysis.

Materials and Methods

Studies, published in English, estimating expression levels of miRNAs with any survival curves in HCC were identified up until 15 April, 2017 by performing online searches in PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews by two independent authors. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used to estimate the correlation between miRNA expression and overall survival (OS).

Results

54 relevant articles about 16 miRNAs, with 6464 patients, were ultimately included. HCC patients with high expression of tissue miR-9 (HR = 2.35, 95% CI = 1.46–3.76), miR-21 (HR = 1.76, 95% CI = 1.29–2.41), miR-34c (HR = 1.64, 95% CI = 1.05–2.57), miR-155 (HR = 2.84, 95% CI = 1.46–5.51), miR-221 (HR = 1.76, 95% CI = 1.02–3.04) or low expression of tissue miR-22 (HR = 2.29, 95% CI = 1.63–3.21), miR-29c (HR = 1.35, 95% CI = 1.10–1.65), miR-34a (HR = 1.84, 95% CI = 1.30–2.59), miR-199a (HR = 2.78, 95% CI = 1.89–4.08), miR-200a (HR = 2.64, 95% CI = 1.86–3.77), miR-203 (HR = 2.20, 95% CI = 1.61–3.00) have significantly poor OS (P < 0.05). Likewise, HCC patients with high expression of blood miR-21 (HR = 1.73, 95% CI = 1.07–2.80), miR-192 (HR = 2.42, 95% CI = 1.15–5.10), miR-224 (HR = 1.56, 95% CI = 1.14–2.12) or low expression of blood miR-148a (HR = 2.26, 95% CI = 1.11–4.59) have significantly short OS (P < 0.05).

Conclusions

In conclusion, tissue miR-9, miR-21, miR-22, miR-29c, miR-34a, miR-34c, miR-155, miR-199a, miR-200a, miR-203, miR-221 and blood miR-21, miR-148a, miR-192, miR-224 demonstrate significantly prognostic value. Among them, tissue miR-9, miR-22, miR-155, miR-199a, miR-200a, miR-203 and blood miR-148a, miR-192 are potential prognostic candidates for predicting OS in HCC.

Quercetin prevents hepatic fibrosis by inhibiting hepatic stellate cell activation and reducing autophagy via the TGF-β1/Smads and PI3K/Akt pathways

The aim of this study was to investigate the effect of quercetin on hepatic fibrosis, a characteristic response to acute or chronic liver injury. Mice were randomized to bile duct ligation (BDL) or carbon tetrachloride (CCl₄) cirrhosis models. Quercetin (100 mg/kg or 200 mg/kg daily) was administered by gavage for 2 or 4 weeks. Liver tissue and blood samples were collected for histological and molecular analysis. The results of our experiments showed that quercetin reduced BDL or CCl₄ liver fibrosis, inhibited extracellular matrix formation, and regulated matrix metallopeptidase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1. Quercetin attenuated liver damage by suppressing the TGF-β1/Smads signaling pathway and activating the PI3K/Akt signaling pathway to inhibit autophagy in BDL- or CCl₄- induced liver fibrosis. Quercetin prevented hepatic fibrosis by attenuating hepatic stellate cell activation and reducing autophagy through regulating crosstalk between the TGF-β1/Smads and PI3K/Akt pathways.

The long noncoding RNA TUG1 acts as a competing endogenous RNA to regulate the Hedgehog pathway by targeting miR-132 in hepatocellular carcinoma

Emerging evidence shows that the Hedgehog pathway and the long noncoding RNA TUG1 play pivotal roles in cell proliferation, migration, and invasion in tumors. However, the mechanism underlying the effect of TUG1 and the Hedgehog pathway in hepatoma remains undefined. In the present study, we showed that the expression of TUG1 was negatively correlated with that of microRNA (miR)-132, and depletion of TUG1 inhibited the activation of the Hedgehog pathway in vitro and in vivo. We showed that TUG1 functions as a competing endogenous (ceRNA) by competing with miR-132 for binding to the sonic hedgehog protein in HCC, thereby suppressing the activation of Hedgehog signaling and its tumorigenic effect. These data indicate that targeting the TUG1-miR132-Hedgehog network could be a new strategy for the treatment of HCC.

Methyl jasmonate leads to necrosis and apoptosis in hepatocellular carcinoma cells via inhibition of glycolysis and represses tumor growth in mice

Methyl jasmonate has recently been found to have anti-cancer activity. Methyl jasmonate detached hexokinase 2 from a voltage dependent anion channel causing a reduction in mitochondrial transmembrane potential that led to the release of cytochrome C and apoptosis inducing factor resulting in intrinsic apoptosis. Blocked adenosine triphosphate synthesis caused by mitochondrial injury hampered oxidative phosphorylation and led to cell necrosis. The results were applied to the in vivo treatment of nude mice with a satisfactory effect. Collectively, our results suggest that methyl jasmonate may be an adjuvant therapy for liver tumors due to its mechanism in cancer cells compared to that in normal cells: The major function is to inhibit glycolysis instead of changing aerobic metabolism.

Epigenetic basis of cancer health disparities: Looking beyond genetic differences

Despite efforts at various levels, racial health disparities still exist in cancer patients. These inequalities in incidence and/or clinical outcome can only be explained by a multitude of factors, with genetic basis being one of them. Several investigations have provided convincing evidence to support epigenetic regulation of cancer-associated genes, which results in the differential transcriptome and proteome, and may be linked to a pre-disposition of individuals of certain race/ethnicity to early or more aggressive cancers. Recent technological advancements and the ability to quickly analyze whole genome have aided in these efforts, and owing to their relatively easy detection, methylation events are much well-characterized, than the acetylation events, across human populations. The early trend of investigating a pre-determined set of genes for differential epigenetic regulation is paving way for more unbiased screening. This review summarizes our current understanding of the epigenetic events that have been tied to the racial differences in cancer incidence and mortality. A better understanding of the epigenetics of racial diversity holds promise for the design and execution of novel strategies targeting the human epigenome for reducing the disparity gaps.

Cocaine-mediated downregulation of microglial miR-124 expression involves promoter DNA methylation

Neuroinflammation plays a critical role in the development of reward-related behavior in cocaine self-administration rodents. Cocaine, one of most commonly abused drugs, has been shown to activate microglia both in vitro and in vivo. Detailed molecular mechanisms underlying cocaine-mediated microglial activation remain poorly understood. microRNAs (miRs) belonging to a class of small noncoding RNA superfamily have been shown to modulate the activation status of microglia. miR-124, one of the microglia-enriched miRs, functions as an anti-inflammatory regulator that maintains microglia in a quiescent state. To date, the possible effects of cocaine on microglial miR-124 levels and the associated underlying mechanisms have not been explored. In the current study, we demonstrated that cocaine exposure decreased miR-124 levels in both BV-2 cells and rat primary microglia. These findings were further validated in vivo, wherein we demonstrated decreased abundance of miR-124 in purified microglia isolated from cocaine-administered mice brains compared with cells from saline administered animals. Molecular mechanisms underlying these effects involved cocaine-mediated increased mRNA and protein expression of DNMTs in microglia. Consistently, cocaine substantially increased promoter DNA methylation levels of miR-124 precursors (pri-miR-124-1 and -2), but not that of pri-miR-124-3, both in vitro and in vivo. In summary, our findings demonstrated that cocaine exposure increased DNA methylation of miR-124 promoter resulting into its downregulation, which, in turn, led to microglial activation. Our results thus implicate that epigenetic modulation of miR-124 could be considered as a potential therapeutic approach to ameliorate microglial activation and, possibly, the development of cocaine addiction.