Genome-wide screening identified that miR-134 acts as a metastasis suppressor by targeting integrin β1 in hepatocellular carcinoma

MicroRNAs involved with hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is one of the most common malignancies, which accounts for 90% of primary liver cancer. HCC usually presents with poor outcomes due to the high rates of tumor recurrence and widespread metastasis. However, the underlying mechanism of HCC initiation and progression, which significantly hindered the development of valid approaches for early detection and treatment remain to be elucidated. As a group of small non-coding RNAs, microRNAs (miRNAs) have been demonstrated to be involved in many types of diseases especially human malignancies. Numerous miRNAs are deregulated in HCC, which may shed some light on current investigations. Since miRNAs are stable and detected easily, their ectopic expression has been reported in HCC tissues, serum/plasma and cell lines. As previously described, miRNAs serve as tumor suppressors or oncogenes, indicating that miRNAs may be useful as diagnostic, therapeutic and prognostic markers of HCC. In the present review, we assessed the latest data regarding dysregulated miRNAs in HCC and reviewed the reported functions of these miRNAs as they apply to the diagnosis and prognosis of HCC.

Detecting cancer biomarkers in blood: challenges for new molecular diagnostic and point-of-care tests using cell-free nucleic acids

As we move into the era of individualized cancer treatment, the need for more sophisticated cancer diagnostics has emerged. Cell-free (cf) nucleic acids (cf-DNA, cf-RNA) and other cellular nanoparticulates are now considered important and selective biomarkers. There is great hope that blood-borne cf-nucleic acids can be used for 'liquid biopsies', replacing more invasive tissue biopsies to analyze cancer mutations and monitor therapy. Conventional techniques for cf-nucleic acid biomarker isolation from blood are generally time-consuming, complicated and expensive. They require relatively large blood samples, which must be processed to serum or plasma before isolation of biomarkers can proceed. Such cumbersome sample preparation also limits the widespread use of powerful, downstream genomic analyses, including PCR and DNA sequencing. These limitations also preclude rapid, point-of-care diagnostic applications. Thus, new technologies that allow rapid isolation of biomarkers directly from blood will permit seamless sample-to-answer solutions that enable next-generation point-of-care molecular diagnostics.

Association of miR-193b down-regulation and miR-196a up-regulation with clinicopathological features and prognosis in gastric cancer

Dysregulated expression of microRNAs (miRNAs) has been shown to be closely associated with tumor development, progression, and carcinogenesis. However, their clinical implications for gastric cancer remain elusive. To investigate the hypothesis that genome-wide alternations of miRNAs differentiate gastric cancer tissues from those matched adjacent non-tumor tissues (ANTTs), miRNA arrays were employed to examine miRNA expression profiles for the 5-pair discovery stage, and the quantitative real-time polymerase chain reaction (qRT- PCR) was applied to validate candidate miRNAs for 48-pair validation stage. Furthermore, the relationship between altered miRNA and clinicopathological features and prognosis of gastric cancer was explored. Among a total of 1,146 miRNAs analyzed, 16 miRNAs were found to be significantly different expressed in tissues from gastric cancer compared to ANTTs (p<0.05). qRT-PCR further confirmed the variation in expression of miR-193b and miR-196a in the validation stage. Down-expression of miR-193b was significantly correlated with Lauren type, differentiation, UICC stage, invasion, and metastasis of gastric cancer (p<0.05), while over-expression of miR-196a was significantly associated with poor differentiation (p=0.022). Moreover, binary logistic regression analysis demonstrated that the UICC stage was a significant risk factor for down-expression of miR-193b (adjusted OR=8.69; 95%CI=1.06-56.91; p=0.043). Additionally, Kaplan-Meier survival curves indicated that patients with a high fold-change of down-regulated miR-193b had a significantly shorter survival time (n=19; median survival=29 months) compared to patients with a low fold-change of down-regulated miR-193b (n=29; median survival=54 months) (p=0.001). Overall survival time of patients with a low fold-change of up-regulated miR- 196a (n=27; median survival=52 months) was significantly longer than that of patients with a high fold-change of up-regulated miR-196a (n=21; median survival=46 months) (p=0.003). Hence, miR-193b and miR-196a may be applied as novel and promising prognostic markers in gastric cancer.

MiR-320a acts as a prognostic factor and Inhibits metastasis of salivary adenoid cystic carcinoma by targeting ITGB3

BACKGROUND

Salivary Adenoid cystic carcinoma (SACC) patients with local invasion and lung metastasis are often resistant to conventional therapy such as operation, chemotherapy and radiotherapy. To explore the underling mechanisms, we studied the roles of miRNA in regulating invasiveness of SACC cells.

METHODS

MicroRNA profiling was done in SACC cells with microarray. MiRNA mimics or antisense oligonucleotide was transfected and invasiveness of SACC cells was evaluated by adhesion assay and transwell assay. The target gene of miRNA was identified by luciferase reporter assay and "rescue" experiment. Tumor metastasis was evaluated by BALB/c-nu mice xenografts. MiRNA and its target gene expression were identified by in-situ hybridization and immunohistochemistry respectively, in 302 patients from affiliated hospitals of Sun Yat-sen University and in 148 patients from affiliated hospitals of Central South University, and correlated to the clinicopathological status of the patients.

RESULTS

MiR-320a was down-regulated in high lung metastatic ACCM and SACC-LM cells compared with the corresponding low metastatic ACC2 and SACC-83 cells, and inhibited adhesion, invasion and migration of SACC cells by targeting integrin beta 3 (ITGB3). In vivo, enforced miR-320a expression suppressed metastasis of SACC xenografts. In the two independent sets, miR-320a was downregulated in primary SACCs with metastasis compared to those without metastasis, and low expression of this miRNA predicts poor patient survival and rapid metastasis. Multivariate analysis showed that miR-320a expression was an independent indicator of lung metastasis.

CONCLUSIONS

MiR-320a inhibits metastasis in SACCs by targeting ITGB3 and may serve as a therapeutic target and prognostic marker in salivary cancers.

Altered levels of circulating miRNAs are associated Schistosoma japonicum infection in mice

Background

Dioecious flatworms of the genus Schistosoma causes schistosomiasis, which is a major public health problem in developing countries. Acquiring detailed knowledge of schistosome-host interactions may aid in the development of novel strategies for schistosomiasis control. MicroRNAs (miRNAs) are involved in processes such as development, cell proliferation, metabolism, and signal transduction. Circulating miRNAs not only serve as a novel class of biomarkers of many diseases but also regulate target gene expression in recipient cells, which are similar to hormones.

Methods

In the present study, we used miRNA microarrays to determine the profile of circulating miRNAs associated with S. japonicum infection of mice. The biological functions of the altered levels of miRNAs and their target genes were predicted using bioinformatics. Expression levels of selected miRNAs and their target genes were further analyzed by quantitative RT-PCR.

Results

Our study identified 294 and 189 miRNAs in infected mice that were expressed in two independent experiments at levels ≥ 2-fold higher or ≤ 0.5-fold lower, respectively, compared with uninfected mice. Thirty-six of the same miRNAs were detected in these analyses. Moreover, pathway analyses indicated that most of these miRNAs are putatively involved in signaling pathways associated with pathogenesis, such as Wnt and MAPK signaling. Further, we show an inverse correlation between the circulating levels of these miRNAs and their target genes, suggesting that changes in miRNA expression may cause aberrant expression of genes such as Creb1 and Caspase-3 in mice infected with S. japonicum.

Conclusions

Our study shows significant differences in the levels of circulating miRNAs between S. japonicum infected mice and uninfected mice. In particular, the altered levels of miR-706 and miR-134-5p were associated with altered levels of expression of the Caspase-3 and Creb1 genes, respectively, suggesting that circulating miRNAs may serve as important mediators of the pathology of hepatic schistosomiasis. Additionally, our results are expected to provide new insights for further understanding the mechanisms of schistosome-host interaction that may facilitate in the development of novel interventions for alleviating the symptom of S. japonicum infection as well as for preventing and treating schistosomiasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-0806-5) contains supplementary material, which is available to authorized users.

MicroRNA Screening and the Quest for Biologically Relevant Targets

MicroRNAs (miRNAs) are a class of genome-encoded small RNAs that post-transcriptionally regulate gene expression by repressing target transcripts containing partially or fully complementary binding sites.

Despite their relatively low number, miRNAs have been shown to directly regulate a large fraction of the transcriptome. In agreement with their pervasive role in the regulation of eukaryotic gene expression, miRNAs have been implicated in virtually all biological processes, including different pathologies.

The use of screening technologies to systematically analyze miRNA function in cell-based assays offers a unique opportunity to gain new insights into complex biological and disease-relevant processes. Given the low complexity of the miRNome and the similarities to small interfering RNA (siRNA) screening experimental approaches, phenotypic screening using genome-wide libraries of miRNA mimics or inhibitors is not, per se, technically challenging. The identification of miRNA targets and, more importantly, the characterization of their mechanisms of action through the identification of the key targets underlying observed phenotypes remain the major challenges of this approach.

This article provides an overview of cell-based screenings for miRNA function that were performed in different biological contexts. The advantages and limitations of computational and experimental approaches commonly used to identify miRNA targets are also discussed.

Marine bromophenol bis (2,3-dibromo-4,5-dihydroxy-phenyl)-methane inhibits the proliferation, migration, and invasion of hepatocellular carcinoma cells via modulating β1-integrin/FAK signaling

Bis (2,3-dibromo-4,5-dihydroxy-phenyl)-methane (BDDPM) is a natural bromophenol compound derived from marine algae. Previous reports have shown that BDDPM possesses antimicrobial activity. In the present study, we found that BDDPM has cytotoxic activity on a wide range of tumor cells, including BEL-7402 cells (IC₅₀ = 8.7 μg/mL). Further studies have shown that prior to the onset of apoptosis, the BDDPM induces BEL-7402 cell detachment by decreasing the adherence of cells to the extracellular matrix (ECM). Detachment experiments have shown that the treatment of BEL-7402 cells with low concentrations of BDDPM (5.0 μg/mL) significantly inhibits cell adhesion to fibronectin and collagen IV as well as cell migration and invasion. High doses of BDDPM (10.0 μg/mL) completely inhibit the migration of BEL-7402 cells, and the expression level of MMPs (MMP-2 and MMP-9) is significantly decreased. Moreover, the expression of β1-integrin and focal adhesion kinase (FAK) is found to be down-regulated by BDDPM. This study suggests that BDDPM has a potential to be developed as a novel anticancer therapeutic agent due to its anti-metastatic activity and also indicates that BDDPM, which has a unique chemical structure, could serve as a lead compound for rational drug design and for future development of anticancer agents.

Reduced expression of microRNA-134 correlates with malignancy and poor prognosis in human glioma

MicroRNA-134 (miR-134) has been demonstrated to be dysregulated in glioma tissues. However, its clinical significance in this tumor type has not been fully elucidated. This study was designed to explore the association of miR-134 expression with clinicopathological features and prognosis in human glioma. Using real-time quantitative polymerase chain reaction, miR-134 expression was detected in 162 glioma specimens with various World Health Organization (WHO) grades and compared to the expression in 36 normal brain tissue samples. Glioma tissues exhibited significantly reduced expression of miR-134 (mean 2.15 ± standard deviation 0.82 versus 4.37 ± 1.16, p<0.001) compared with normal brain tissues. In addition, miR-134 expression was notably associated with WHO grade (p<0.001) and Karnofsky Performance Scale score (KPS; p=0.02) in glioma tissues. Low miR-134 expression occurred more frequently in glioma tissues with high WHO grades and low KPS scores. In univariate analysis, both progression-free survival (PFS) and overall survival (OS) of glioma patients with low miR-134 expression were significantly shorter than those with high miR-134 expression (both p<0.001). Additionally, glioma patients with high WHO grades, low KPS scores and subtotal resection attained significantly poorer PFS (p<0.001, 0.02 and 0.01, respectively) and OS (p<0.001, 0.01 and 0.01, respectively). In multivariate analysis, miR-134 expression, WHO grade, KPS score and extent of resection were identified as the independent prognostic factors for both PFS and OS. Collectively, our data prove that the reduced expression of miR-134 may predict aggressive progression and poor prognosis in human gliomas. miR-134 may represent both a prognostic marker and a novel therapeutic target for this malignancy.

Dysregulated Serum MicroRNA Expression Profile and Potential Biomarkers in Hepatitis C Virus-infected Patients

OBJECTIVES

Circulating microRNAs (miRNAs) play critical roles in pathogen-host interactions. Aberrant miRNA expression profiles might have specific characteristics for virus strains, and could serve as noninvasive biomarkers for screening and diagnosing infectious diseases. In this study, we aimed to find new potential miRNA biomarkers of hepatitis C virus (HCV) infection.

METHODS

Expression levels of broad-spectrum miRNAs in serum samples from 10 patients with HCV viremia and 10 healthy volunteers were analyzed using miRNA PCR arrays. Subsequently, the differential expression of four selected miRNAs (miR-122, miR-134, miR-424-3p, and miR-629-5p) was verified by qRT-PCR in the serum of 39 patients compared with that in 29 healthy controls. Receiver operating characteristic (ROC) curve analysis was performed to evaluate their potential for the diagnosis of HCV infection.

RESULTS

miRNA PCR array assays revealed differential expression of 106 miRNAs in sera of HCV patients compared with that in healthy controls. Serum hsa-miR-122, miR-134, miR-424-3p, and miR-629-5p were well identified. The ROC curves showed that miR-122, miR-134, miR-424-3p, and miR-629-5p could distinguish HCV patients with preferable sensitivity and specificity. In addition, Correlation analysis indicated serum miR-122 expression was positive correlation with ALT/AST levels. Functional analysis of target proteins of these miRNAs indicated the involvement of viral replication, inflammation, and cell proliferation.

CONCLUSION

HCV patients have a broad 'fingerprint' profile with dysregulated serum miRNAs compared with that in healthy controls. Among these, serum hsa-miR-122, miR-134, miR-424-3p, and miR-629-5p are identified as promising indication factors of the serum miRNA profile of HCV infection. Particularly, miR-122 could be one of serum biomarkers for early pathological process of HCV. However, more miRNA biomarkers and biological functions of these miRNAs require further investigation.

MicroRNA-134 suppresses endometrial cancer stem cells by targeting POGLUT1 and Notch pathway proteins

We aimed to ascertain the role of microRNAs (miRNAs) in regulating human endometrial cancer stem cells (HuECSCs). The expression level of miRNA-134 (miR-134), a member of the DLK1-DIO3 genomic imprinted miRNA cluster, differed significantly between HuECSCs and human endometrial cancer cells (HuECCs). miR-134 inhibited HuECSCs proliferation and migration by targeting protein O-glucosyltransferase 1 (POGLUT1) expression. Exogenous miR-134 overexpression downregulated POGLUT1 and Notch pathway proteins in HuECSCs in vitro. miR-134 overexpression affected the G2/M phase of HuECSCs and suppressed the growth of xenograft tumours formed. Thus, endogenous miR-134 regulation in HuECSCs may suppress tumourigenesis in human endometrial carcinoma.

miRNome of inflammatory breast cancer

BACKGROUND

Inflammatory breast cancer (IBC) is an extremely malignant form of breast cancer which can be easily misdiagnosed. Conclusive prognostic IBC molecular biomarkers which are also providing the perspectives for targeted therapy are lacking so far. The aim of this study was to reveal the IBC-specific miRNA expression profile and to evaluate its association with clinicopathological parameters.

METHODS

miRNA expression profiles of 13 IBC and 17 non-IBC patients were characterized using comprehensive Affymetrix GeneChip miRNA 3.0 microarray platform. Bioinformatic analysis was used to reveal IBC-specific miRNAs, deregulated pathways and potential miRNA targets.

RESULTS

31 differentially expressed miRNAs characterize IBC and mRNAs regulated by them and their associated pathways can functionally be attributed to IBC progression. In addition, a minimal predictive set of 4 miRNAs characteristic for the IBC phenotype and associated with the TP53 mutational status in breast cancer patients was identified.

CONCLUSIONS

We have characterized the complete miRNome of inflammatory breast cancer and found differentially expressed miRNAs which reliably classify the patients to IBC and non-IBC groups. We found that the mRNAs and pathways likely regulated by these miRNAs are highly relevant to cancer progression. Furthermore a minimal IBC-related predictive set of 4 miRNAs associated with the TP53 mutational status and survival for breast cancer patients was identified.

A novel cancer-germline transcript carrying pro-metastatic miR-105 and TET-targeting miR-767 induced by DNA hypomethylation in tumors

Genome hypomethylation is a common epigenetic alteration in human tumors, where it often leads to aberrant activation of a group of germline-specific genes, commonly referred to as “cancer-germline” genes. The cellular functions and tumor promoting potential of these genes remain, however, largely uncertain. Here, we report identification of a novel cancer-germline transcript (CT-GABRA3) displaying DNA hypomethylation-dependent activation in various tumors, including melanoma and lung carcinoma. Importantly, CT-GABRA3 harbors a microRNA (miR-105), which has recently been identified as a promoter of cancer metastasis by its ability to weaken vascular endothelial barriers following exosomal secretion. CT-GABRA3 also carries a microRNA (miR-767) with predicted target sites in TET1 and TET3, two members of the ten-eleven-translocation family of tumor suppressor genes, which are involved in the conversion of 5-methylcytosines to 5-hydroxymethylcytosines (5hmC) in DNA. Decreased TET activity is a hallmark of cancer; here, we provide evidence that aberrant activation of miR-767 contributes to this phenomenon. We demonstrate that miR-767 represses TET1/3 mRNA and protein expression and regulates genomic 5hmC levels. Additionally, we show that high CT-GABRA3 transcription correlates with reduced TET1 mRNA levels in vivo in lung tumors. Together, our study identified a cancer-germline gene that produces microRNAs with oncogenic potential. Moreover, our data indicate that DNA hypomethylation in tumors can contribute to reduced 5hmC levels via activation of a TET-targeting microRNA.

MiR-525-3p enhances the migration and invasion of liver cancer cells by downregulating ZNF395

Liver cancer is one of leading causes of cancer-related deaths. A deeper mechanistic understanding of liver cancer could lead to the development of more effective therapeutic strategies. In our previous work, we screened 646 miRNAs and identified 11 that regulate liver cancer cell migration. The current study shows that miR-525-3p is frequently up-regulated in liver cancer tissues, and enhanced expression of miR-525-3p can promote liver cancer cell migration and invasion. Zinc finger protein 395 (ZNF395) is the direct functional target gene for miR-525-3p, and it is frequently down-regulated in liver cancer tissues. High expression of ZNF395 can significantly inhibit while knockdown of ZNF395 expression can markedly enhance the migration and invasion of liver cancer cells, suggesting that ZNF395 suppresses metastasis in liver cancer. Down-regulation of ZNF395 can mediate miR-525-3p induced liver cancer cell migration and invasion. In conclusion, miR-525-3p promotes liver cancer cell migration and invasion by directly targeting ZNF395, and the fact that miR-525-3p and ZNF395 both play important roles in liver cancer progression makes them potential therapeutic targets.