Inhibitions of epithelial to mesenchymal transition and cancer stem cells-like properties are involved in miR-148a-mediated anti-metastasis of hepatocellular carcinoma

MicroRNA as Key Players in Hepatocellular Carcinoma: Insights into Their Role in Metastasis

Liver cancer or hepatocellular carcinoma (HCC) remains the most common cancer in global epidemiology. Both the frequency and fatality of this malignancy have shown an upward trend over recent decades. Liver cancer is a significant concern due to its propensity for both intrahepatic and extrahepatic metastasis. Liver cancer metastasis is a multifaceted process characterized by cell detachment from the bulk tumor, modulation of cellular motility and invasiveness, enhanced proliferation, avoidance of the immune system, and spread either via lymphatic or blood vessels. MicroRNAs (miRNAs) are small non-coding ribonucleic acids (RNAs) playing a crucial function in the intricate mechanisms of tumor metastasis. A number of miRNAs can either increase or reduce metastasis via several mechanisms, such as control of motility, proliferation, attack by the immune system, cancer stem cell properties, altering the microenvironment, and the epithelial-mesenchymal transition (EMT). Besides, two other types of non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) can competitively bind to endogenous miRNAs. This competition results in the impaired ability of the miRNAs to inhibit the expression of the specific messenger RNAs (mRNAs) that are targeted. Increasing evidence has shown that the regulatory axis comprising circRNA/lncRNA-miRNA-mRNA is correlated with the regulation of HCC metastasis. This review seeks to present a thorough summary of recent research on miRNAs in HCC, and their roles in the cellular processes of EMT, invasion and migration, as well as the metastasis of malignant cells. Finally, we discuss the function of the lncRNA/circRNA-miRNA-mRNA network as a crucial modulator of carcinogenesis and the regulation of signaling pathways or genes that are relevant to the metastasis of HCC. These findings have the potential to offer valuable insight into the discovery of novel therapeutic approaches for management of liver cancer metastasis.

Potential targets and therapeutics for cancer stem cell-based therapy against drug resistance in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common digestive malignancyin the world, which is frequently diagnosed at late stage with a poor prognosis. For most patients with advanced HCC, the therapeutic options arelimiteddue to cancer occurrence of drug resistance. Hepatic cancer stem cells (CSCs) account for a small subset of tumor cells with the ability of self-renewal and differentiationin HCC. It is widely recognized that the presence of CSCs contributes to primary and acquired drug resistance. Therefore, hepatic CSCs-targeted therapy is considered as a promising strategy to overcome drug resistance and improve therapeutic outcome in HCC. In this article, we review drug resistance in HCC and provide a summary of potential targets for CSCs-based therapy. In addition, the development of CSCs-targeted therapeuticsagainst drug resistance in HCC is summarized in both preclinical and clinical trials. The in-depth understanding of CSCs-related drug resistance in HCC will favor optimization of the current therapeutic strategies and gain encouraging therapeutic outcomes.

Paclitaxel-induced inhibition of NSCLC invasion and migration via RBFOX3-mediated circIGF1R biogenesis

We previously reported that circIGF1R is significantly downregulated in non-small cell lung cancer (NSCLC) cells and tissues. It inhibits cancer cell invasion and migration, although the underlying molecular mechanisms remain elusive. The invasion and migration of NSCLC cells was analyzed by routine in vivo and in vitro functional assays. Fluorescent in situ hybridization, luciferase reporter assay, RNA pull-down assay and RNA immunoprecipitation (RIP) assay were performed to explore the molecular mechanisms. Mechanism of action of paclitaxel-induced RBFOX3-mediated inhibition of NSCLC invasion and migration was investigated through in vitro and in vivo experiments.Our study reveals that circIGF1R acts as a Competing Endogenous RNA (ceRNA) for miR-1270, thereby regulating Van-Gogh-like 2 (VANGL2) expression and subsequently inhibiting NSCLC cell invasion and migration via the Wnt pathway. We also found that RNA binding protein fox-1 homolog 3 (RBFOX3) enhances circIGF1R biogenesis by binding to IGF1R pre-mRNA, which in turn suppresses migration and invasion in NSCLC cells. Additionally, the chemotherapeutic drug paclitaxel was shown to impede NSCLC invasion and migration by inducing RBFOX3-mediated circIGF1R biogenesis.RBFOX3 inhibits the invasion and migration of NSCLC cells through the circIGF1R/ miR-1270/VANGL2 axis, circIGF1R has the potential to serve as a biomarker and therapeutic target for NSCLC.

Wnt/β-Catenin Signaling as a Driver of Stemness and Metabolic Reprogramming in Hepatocellular Carcinoma

Simple Summary

Aberrant Wnt/β-catenin signaling has been reported to play crucial role in pathogenesis of hepatocellular carcinoma (HCC). In this review, we focus on the regulatory role of Wnt/β-catenin signaling in cancer stemness and metabolic reprogramming, which are two emerging hallmarks of cancer. Understanding the role of Wnt/β-catenin signaling in regulation of the above processes reveals novel therapeutic strategy against this deadly disease.

Abstract

Hepatocellular carcinoma (HCC) is a major cause of cancer death worldwide due to its high rates of tumor recurrence and metastasis. Aberrant Wnt/β-catenin signaling has been shown to play a significant role in HCC development, progression and clinical impact on tumor behavior. Accumulating evidence has revealed the critical involvement of Wnt/β-catenin signaling in driving cancer stemness and metabolic reprogramming, which are regarded as emerging cancer hallmarks. In this review, we summarize the regulatory mechanism of Wnt/β-catenin signaling and its role in HCC. Furthermore, we provide an update on the regulatory roles of Wnt/β-catenin signaling in metabolic reprogramming, cancer stemness and drug resistance in HCC. We also provide an update on preclinical and clinical studies targeting Wnt/β-catenin signaling alone or in combination with current therapies for effective cancer therapy. This review provides insights into the current opportunities and challenges of targeting this signaling pathway in HCC.

Inverse relationship between the level of miRNA 148a-3p and both TGF-β1 and FIB-4 in hepatocellular carcinoma

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is a major health burden globally. Dysregulation of miRNA 148a-3p is engaged in carcinogenesis. TGF-β is a profibrogenic cytokine. This study assesses the expression level of miRNA 148a-3p and its relationship with serum TGF-β1 and fibrosis index based on four factors (FIB-4) in Egyptian patients with HCV-associated HCC.

SUBJECTS

and Methods: The study included 72 HCC patients with HCV, 48 HCV cirrhotic patients, and 47 healthy controls. Serum TGF-β1 was assessed by ELISA and the expression of miRNA 148a-3p was measured by RT-PCR.

RESULTS

Patients with HCC had lower plasma miRNA 148a-3p, higher serum TGF-β1, and higher FIB-4 levels than patients with cirrhosis and controls. miRNA 148a-3p discriminated HCC either from control (AUC: 0.997, 95.83% sensitivity, 85.11% specificity) or from cirrhosis (AUC: 0.943, 91.67% sensitivity, 81.25% specificity). Moreover, it distinguished metastatic from nonmetastatic patients (AUC: 0.800, 88.89% sensitivity, 60.0% specificity). The decreased miRNA 148a-3p and the increased TGF-β1 levels were related to distant metastasis, multinodular lesions, advanced TNM stage, and BCLC score (C). A negative correlation between miRNA 148a-3p and each of FIB-4 and TGF-β1 was detected. The decreased miRNA 148a-3p was associated with poor overall survival and poor progression-free survival.

CONCLUSION

An inverse relationship between miRNA 148a-3p and both TGF-β1 and FIB-4 was observed, which could be involved in HCC pathogenesis. Moreover, this miRNA is a potential diagnostic and prognostic biomarker for HCC.

27-Hydroxycholesterol is a specific factor in the neoplastic microenvironment of HCC that causes MDR via GRP75 regulation of the redox balance and metabolic reprogramming

OBJECTIVE

Due to the tissue specificity of the liver, long-term exposure to a high concentration of 27-hydroxycholesterol (27HC) is a special characteristic of the tumour microenvironment in hepatocellular carcinoma (HCC). However, what occurs after HCC cells are long-term exposure to 27HC and the molecular mechanisms involved remain largely unexamined.

METHODS

A long-term 27HC-treated HepG2 cell line and the xenografts in nude mice were used as experimental models. Molecular mechanisms were investigated using bioinformatics analysis and molecular biological experiments.

RESULTS

Here, we found that by inducing an increase in oxidative stress signalling, 27HC activated glucose-regulated protein 75 (GRP75). On the one hand, GRP75 resulted in a change in the redox balance by regulating ROS generation and antioxidant system activity via affecting MMP, NRF2, HO-1, and NQO1 levels. On the other hand, GRP75 modified the metabolic reprogramming process by regulating key factors (HIF-1α, p-Akt, and c-myc) and glucose uptake, facilitating HCC cell growth in the inhospitable microenvironment. These two factors caused HCC cells to resist 27HC-induced cytotoxicity and attain multidrug resistance (MDR).

CONCLUSIONS

Our present study not only identified 27HC, a characteristic component of the neoplastic microenvironment of HCC that causes MDR via GRP75 to regulate the redox balance and metabolic reprogramming, but also revealed that targeted intervention by the "switch"-like molecule GRP75 could reverse the effect of 27HC from cancer promotion to cytotoxicity in HCC, suggesting a new strategy for specific intervention of HCC.

Advances in Liver Cancer Stem Cell Isolation and their Characterization

Over the last decade research on cancer stem cells (CSC) significantly contributed to a better understanding of tumor biology. Given their similarity to normal stem cells, i.e. self-renewal and pluripotency the need arises to develop robust protocols for the isolation and characterization of CSCs. As with other malignancies, hepatic tumors are composed of a heterogeneous population of cells including liver cancer stem cells (LCSC). Yet, a precise understanding of why stem cells become cancerous is still lacking. There is unmet need to develop robust protocols for the successful isolation of LCSCs from human tissue resection material as to assist in the development of molecular targeted therapies. Here we review the research progress made in the isolation and characterization of LCSCs by considering a wide range of cell surface markers and sorting methods, as applied to side populations, microsphere cultures and the gradient centrifugation method. We emphasize the different fluorescence activated cell sorting methods and the possibility to enrich LCSCs by immunomagnetic beads. We review the specificity of functional assays by considering ABCG transporter and ALDH1 enzyme activities and evaluate the in vivo tumorigenicity of LCSCs in highly sensitive bioassays. Finally, we evaluate different LCSC markers in association with viral and non-viral liver disease and explore the potential of novel drug delivery systems targeting CD133, EpCAM, CD13 and CD90 for the development of molecular targeted therapies. Graphical Abstract.

Regulators at Every Step-How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial-mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Regulators at Every Step—How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

MicroRNA-148a-3p suppresses epithelial-to-mesenchymal transition and stemness properties via Wnt1-mediated Wnt/β-catenin pathway in pancreatic cancer

Although miR-148a-3p has been reported to function as a tumour suppressor in various cancers, the molecular mechanism of miR-148a-3p in regulating epithelial-to-mesenchymal transition (EMT) and stemness properties of pancreatic cancer (PC) cells remains to be elucidated. In the present study, we demonstrated that miR-148a-3p expression was remarkably down-regulated in PC tissues and cell lines. Moreover, low expression of miR-148a-3p was associated with poorer overall survival (OS) in patients with PC. In vitro, gain-of-function and loss-of-function experiments showed that miR-148a-3p suppressed EMT and stemness properties as well as the proliferation, migration and invasion of PC cells. A dual-luciferase reporter assay demonstrated that Wnt1 was a direct target of miR-148a-3p, and its expression was inversely associated with miR-148a-3p in PC tissues. Furthermore, miR-148a-3p suppressed the Wnt/β-catenin pathway via down-regulation of Wnt1. The effects of ectopic miR-148a-3p were rescued by Wnt1 overexpression. These biological functions of miR-148a-3p in PC were also confirmed in a nude mouse xenograft model. Taken together, these findings suggest that miR-148a-3p suppresses PC cell proliferation, invasion, EMT and stemness properties via inhibiting Wnt1-mediated Wnt/β-catenin pathway and could be a potential prognostic biomarker as well as a therapeutic target in PC.

MicroRNA-148a-3p inhibits progression of hepatocelluar carcimoma by repressing SMAD2 expression in an Ago2 dependent manner

Background

Hepatocellular carcinoma (HCC) is one of the most prevalent common cancer worldwide with high mortality. Transforming growth factor-β (TGF-β) signaling pathway was reported dysregulated during liver cancer formation and progression. As a key component of TGF-β signaling, the role of SMAD2 and its regulatory mechanisms in HCC remain unclear.

Methods

SMAD2 expression in paired HCC specimens were determined by western blot and immunohistochemistry (IHC). quantitative real-time PCR (qRT-PCR) was used to measure mRNA and microRNA (miRNA) expression level. Cell migration, invasion and proliferation ability were evaluated by transwell, CCK8 and EdU assay. In silico websites were used to manifest overall survival rates of HCC patients or to predict miRNAs targeting SMAD2. Dual luciferase reporter assay and anti-Ago2 immunoprecipitation assay were performed to confirm the binding between SMAD2 mRNA and miRNA-148a-3p (miR-148a). Tumorigenesis and lung metastasis mouse model were used to explore the role of miR-148a in vivo. In situ hybridization (ISH) was conducted to determine the expression of miR-148a in liver tissues.

Results

In this study, we found that SMAD2 was highly expressed in HCC and elevated SMAD2 expression predicted shorter overall survival (OS) time for HCC patients. SMAD2 promoted mobility and proliferation of HCC cells in vitro. We further revealed that the expression of miR-148a was negatively correlated with SMAD2 and found that miR-148a repressed SMAD2 expression by downregulating its mRNA through binding with Argonaute 2 (Ago2) in HCC. Transwell, CCK8 and animal experiments exhibited miR-148a inhibited metastasis and proliferation of HCC in vitro and in vivo. Moreover, the phenotype changes caused by miR-148a manipulation were recovered by rescuing SMAD2 expression in HCC cells. ISH assay indicated miR-148a was downregulated in HCC and low expression of miR-148a associated with more aggressive clinic features and poor prognosis.

Conclusion

miR-148a was identified as a repressor of HCC progression by downregulating SMAD2 in an Ago2 dependent manner.

MicroRNAs target the Wnt/β‑catenin signaling pathway to regulate epithelial‑mesenchymal transition in cancer (Review)

Epithelial‑mesenchymal transition (EMT), during which cancer cells lose the epithelial phenotype and gain the mesenchymal phenotype, has been verified to result in tumor migration and invasion. Numerous studies have shown that dysregulation of the Wnt/β‑catenin signaling pathway gives rise to EMT, which is characterized by nuclear translocation of β‑catenin and E‑cadherin suppression. Wnt/β‑catenin signaling was confirmed to be affected by microRNAs (miRNAs), several of which are down‑ or upregulated in metastatic cancer cells, indicating their complex roles in Wnt/β‑catenin signaling. In this review, we demonstrated the targets of various miRNAs in altering Wnt/β‑catenin signaling to promote or inhibit EMT, which may elucidate the underlying mechanism of EMT regulation by miRNAs and provide evidence for potential therapeutic targets in the treatment of invasive tumors.

Identification of plasma miR-148a as a noninvasive biomarker for hepatocellular carcinoma

BACKGROUND

The detection of microRNA (miRNA) markers in plasma is a potential strategy for hepatocellular carcinoma (HCC) screening. The aim of this study was to characterize miR-148a in the peripheral plasma as a non-invasive biomarker for the diagnosis of HCC.

METHODS AND METHODS

Quantification of miR-148a was performed on 346 plasma samples, including 155 patients with HCC, 96 patients with liver cirrhosis and 95 healthy controls using quantitative real-time PCR (qRT-PCR). Plasma miR-148a was compared before and after the removal of the tumor in 97 cases of HCC. Receiver operating characteristic (ROC) curves were generated to analyze predictive value of plasma miR148a in HCC.

RESULTS

Plasma miR-148a levels were significantly lower in HCC patients compared to those with liver cirrhosis (P < 0.01) or healthy controls (P < 0.01). The area under receiver operating characteristic (AUROC) curve for plasma miR-148a was 0.919, with a sensitivity of 89.6 % and a specificity of 89.0% for HCC patients compared with liver cirrhosis. In HCC patients with negative or low AFP, AUROC values for plasma miR-148a were 0.949, with a sensitivity of 90.6% and a specificity of 92.6%. The removal of primary HCC tumor led to increased plasma miR-148a levels (P < 0.0001), indicating that miR-148a is a HCC-specific biomarker.

CONCLUSION

Plasma miR-148a is a potential non-invasive biomarker for HCC screening, especially for those with negative or low AFP. Detection of miR-148a might be a complementary approach to AFP for predicting HCC occurrence.

Interplay of Wnt β-catenin pathway and miRNAs in HBV pathogenesis leading to HCC

The prevalence of Hepatocellular carcinoma (HCC) has been identified world-wide. Plethora of factors including chronic infection of HBV/HCV has been characterized for the development of HCC. Although the onset and progression of HCC has been linked with awry of various signaling pathways but precise mechanism, still lies under the multitude layers of curiosity. HBV is spreading with insane speed throughout the world and has been found a main culprit in HCC development after regulating the several cellular pathways including Wnt/β-catenin, Raf/MAPK, Akt and affecting cell multiplication to genomic instability. The role of Wnt/FZD/β-catenin signaling pathway is centralized in liver functions and its anomalous activation leads to HCC development. β-catenin mainly plays a pivotal role in canonical pathway of the system. Altered mainly overexpression of β-catenin along its nuclear localization tunes the aberrations in liver functions and set disease progression. In the development of HCC, modulation of Wnt/FZD/β-catenin signaling pathway by HBV has been established. As HBV infects the cell it affects the miRNAs, the master regulators of cell. Previous studies showed the connection between HBV and cellular miRNAs. In the present review, we unveiled how HBV is deciphering the cellular miRNAs like miR-26a, miR-15a, miR-16-1, miR-148a, miR-132, miR-122, miR-34a, miR-21, miR-29a, miR-222 and miR-199a/b-3p to modulate the Wnt/FZD/β-catenin signaling pathway and develop HCC. These HBV mediated miRNAs may prove future therapeutic options to treat HBV-Wnt/FZD/β-catenin associated HCC.

Reversal of sorafenib resistance in hepatocellular carcinoma: epigenetically regulated disruption of 14-3-3η/hypoxia-inducible factor-1α

Sorafenib resistance is one of the main obstacles to the treatment of advanced/recurrent hepatocellular carcinoma (HCC). Here, sorafenib-resistant HCC cells and xenografts in nude mice were used as experimental models. A cohort of patients with advanced recurrent HCC who were receiving sorafenib therapy was used to assess the clinical significance of this therapy. Our data showed that 14-3-3η maintained sorafenib resistance in HCC. An analysis of the underlying molecular mechanisms revealed that 14-3-3η stabilizes hypoxia-inducible factor 1α (HIF-1α) through the inhibition of ubiquitin-dependent proteasome protein degradation, which leads to the maintenance of cancer stem cell (CSC) properties. We further found that microRNA-16 (miR-16) is a competent miRNA that reverses sorafenib resistance by targeting the 3'-UTR of 14-3-3η and thereby inhibits 14-3-3η/HIF-1α/CSC properties. In HCC patients, significant negative correlations were found between the expression of miR-16 and 14-3-3η, HIF-1α, or CSC properties. Further analysis showed that low miR-16 expression but high 14-3-3η expression can prognosticate sorafenib resistance and poor survival. Collectively, our present study indicated that miR-16/14-3-3η is involved in sorafenib resistance in HCC and that these two factors could be potential therapeutic targets and biomarkers for predicting the response to sorafenib treatment.

Role of non-coding RNAs in liver disease progression to hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a tumor with poor prognosis and frequently aggressive. The development of HCC is associated with fibrosis and cirrhosis, which mainly results from nonalcoholic fatty liver disease, excessive alcohol consumption, and viral infections. Non-coding RNAs (ncRNAs) are RNAs transcribed from the genome, but are not translated into proteins. Recently, ncRNAs emerged as key contributors to tumor development and progression because of their abilities to regulate various targets and modulate cell proliferation, differentiation, apoptosis, and development. In this review, we summarize the frequently activated pathways in HCC and discuss the pathological implications of ncRNAs in the context of human liver disease progression, in particular HCC development and progression. This review aims to summarize the role of ncRNA dysregulation in the diseases and discuss the diagnostic and therapeutic potentials of ncRNAs.

The Epigenetic Regulation of HCC Metastasis

Epigenetic alterations, such as histone modification, DNA methylation, and miRNA-mediated processes, are critically associated with various mechanisms of proliferation and metastasis in several types of cancer. To overcome the side effects and limited effectiveness of drugs for cancer treatment, there is a continuous need for the identification of more effective drug targets and the execution of mechanism of action (MOA) studies. Recently, epigenetic modifiers have been recognized as important therapeutic targets for hepatocellular carcinoma (HCC) based on their reported abilities to suppress HCC metastasis and proliferation in both in vivo and in vitro studies. Therefore, here, we introduce epigenetic modifiers and alterations related to HCC metastasis and proliferation, and their molecular mechanisms in HCC metastasis. The existing data suggest that the study of epigenetic modifiers is important for the development of specific inhibitors and diagnostic targets for HCC treatment.

H19/miR-148a/USP4 axis facilitates liver fibrosis by enhancing TGF-β signaling in both hepatic stellate cells and hepatocytes

Liver fibrosis is a wound-healing response represented by excessive extracellular matrix deposition. Activation of hepatic stellate cell (HSC) is the critical cellular basis for hepatic fibrogenesis, whereas hepatocyte undergoes epithelial-mesenchymal transition (EMT) which is also involved in chronic liver injury. Long noncoding RNA H19 has been found to be associated with cholestatic liver fibrosis lately. However, the role of H19 in liver fibrosis remains largely to be elucidated. In this study, we found that the expression of H19 was significantly upregulated in the liver tissue of CCl₄ -induced mice, a toxicant-induced liver fibrogenesis model. Overexpression of H19 significantly aggravated activation of HSC and EMT of hepatocyte both by stimulating transforming growth factor-β (TGF-β) pathway. In terms of mechanism, H19 functioned as a competing endogenous RNA to sponge miR-148a and subsequently sustained the level of ubiquitin-specific protease 4 (USP4), which was an identified target of miR-148a and was able to stabilize TGF-β receptor I. In conclusion, our findings revealed a novel H19/miR-148a/USP4 axis which promoted liver fibrosis via TGF-β pathway in both HSC and hepatocyte, indicating that H19 could become a promising target for the treatment of liver fibrosis.

Interplay of miRNAs and Canonical Wnt Signaling Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the leading causes of cancer death worldwide and the activation of canonical Wnt signaling pathway is universal in hepatocellular carcinoma patients. MicroRNAs are found to participate in the pathogenesis of hepatocellular carcinoma by activating or inhibiting components in the canonical Wnt signaling pathway. Meanwhile, transcriptional activation of microRNAs by canonical Wnt signaling pathway also contributes to the occurrence and progression of hepatocellular carcinoma. Pharmacological inhibition of hepatocellular carcinoma pathogenesis and other cancers by microRNAs are now in clinical trials despite the challenges of identifying efficient microRNAs candidates and safe delivery vehicles. The focus of this review is on the interplay mechanisms between microRNAs and canonical Wnt signaling pathway in hepatocellular carcinoma, and a deep understanding of the crosstalk will promote to develop a better management of this disease.

Small but Heavy Role: MicroRNAs in Hepatocellular Carcinoma Progression

Hepatocellular carcinoma (HCC), which accounts for 85-90% of primary liver cancer, is the fifth most common malignant tumor and the third leading cause of cancer-related deaths worldwide, but the pathological mechanism of HCC is still not fully elucidated. miRNAs are evolutionarily endogenous small noncoding RNAs that negatively regulate gene expression via posttranscriptional inhibition or target mRNA degradation in several diseases, especially human cancer. Therefore, discovering the roles of miRNAs is appealing to scientific researchers. Emerging evidence has shown that the aberrant expressions of numerous miRNAs are involved in many HCC biological processes. In hepatocarcinogenesis, miRNAs with dysregulated expression can exert their function as oncogenes or tumor suppressors depending on their cellular target during the cell cycle, and in tumor development, differentiation, apoptosis, angiogenesis, metastasis, and progression of the tumor microenvironment. In this review, we summarize current findings on miRNAs and assess their functions to explore the molecular mechanisms of tumor progression in HCC.

MiR-148a increases glioma cell migration and invasion by downregulating GADD45A in human gliomas with IDH1 R132H mutations

High-grade gliomas are severe tumors with poor prognosis. An R132H mutation in the isocitrate dehydrogenase (IDH1) gene prolongs the life of glioma patients. In this study, we investigated which genes are differentially regulated in IDH1 wild type (IDH1^WT) or IDH1 R132H mutation (IDH1^R132H) glioblastoma cells. Growth arrest and DNA-damage-inducible protein (GADD45A) was downregulated and microRNA 148a (miR-148a) was upregulated in in IDH1^R132H human glioblastomas tissues. The relationship between GADD45A and miR-148a is unknown. In vitro experiments showed that GADD45A negatively regulates IDH1^R132H glioma cell proliferation, migration, and invasion, and neurosphere formation in IDH1^R132H glioblastoma stem cells (GSC). In addition, a human orthotopic xenograft mouse model showed that GADD45A reduced tumorigenesis in vivo. Our findings demonstrated that miR-148a promotes glioma cell invasion and tumorigenesis by downregulating GADD45A. Our findings provide novel insights into how GADD45A is downregulated by miR-148a in IDH1^R132H glioma and may help to identify therapeutic targets for the effective treatment of high-grade glioma.

Serum exosomal microRNAs combined with alpha-fetoprotein as diagnostic markers of hepatocellular carcinoma

Exosomal microRNAs have recently been studied as the potential diagnostic marker for various malignancies, including hepatocellular carcinoma (HCC). The aim of this study was to investigate serum exosomal microRNA profiles as HCC diagnostic marker. Transmission electron microscopy and Western blot were used to identify serum exosomes. Deep sequencing was performed to screen differentially expressed microRNAs between HCC (n = 5) and liver cirrhosis (LC, n = 5) groups. Three upregulated and two downregulated microRNAs were selected for qPCR analysis. The levels of selected microRNAs were normalized to Caenorhabditis elegans miR-39 microRNA mimics. Serum exosomal level of miR-122, miR-148a, and miR-1246 was further analyzed and significantly higher in HCC than LC and normal control (NC) groups (P < 0.001), but not different from chronic hepatitis group (P > 0.05). The receiver operating characteristic curve was used to evaluate the diagnostic performance of candidate microRNAs. Area under the curve (AUC) of miR-148a was 0.891 [95% confidence interval (CI), 0.809-0.947] in discriminating HCC from LC, remarkably higher than alpha-fetoprotein (AFP) (AUC: 0.712, 95% CI: 0.607-0.803). Binary logistic regression was adopted to establish the diagnostic model for discriminating HCC from LC. And the combination of miR-122, miR-148a, and AFP increased the AUC to 0.931 (95% CI, 0.857-0.973), which can also be applied for distinguishing early HCC from LC. miR-122 was the best for differentiating HCC from NC (AUC: 0.990, 95% CI, 0.945-1.000). These data suggest that serum exosomal microRNAs signature or their combination with traditional biomarker may be used as a suitable peripheral screening tool for HCC.

The crosstalk between microRNAs and the Wnt/β-catenin signaling pathway in cancer

Mounting evidence has indicated microRNA (miR) dysregulation and the Wnt/β-catenin signaling pathway jointly drive carcinogenesis, cancer metastasis, and drug-resistance. The current review will focus on the role of the crosstalk between miRs and the Wnt/β-catenin signaling pathway in cancer development. MiRs were found to activate or inhibit the canonical Wnt pathway at various steps. On the other hand, Wnt activation increases expression of miR by directly binding to its promoter and activating transcription. Moreover, there are mutual feedback loops between some miRs and the Wnt/β-catenin signaling pathway. Clinical trials of miR-based therapeutic agents are investigated for solid and hematological tumors, however, challenges concerning low bioavailability and possible side effects must be overcome before the final clinical application. This review will describe current understanding of miR crosstalk with the Wnt/β-catenin signaling cascade. Better understanding of the regulatory network will provide insight into miR-based therapeutic development.

Alterations of microRNAs throughout the malignant evolution of cutaneous squamous cell carcinoma: the role of miR-497 in epithelial to mesenchymal transition of keratinocytes

Skin carcinogenesis is known to be a multi-step process with several stages along its malignant evolution. We hypothesized that transformation of normal epidermis to cutaneous squamous cell carcinoma (cSCC) is causally linked to alterations in microRNAs (miRNA) expression. For this end we decided to evaluate their alterations in the pathologic states ending in cSCC. Total RNA was extracted from formalin fixed paraffin embedded biopsies of five stages along the malignant evolution of keratinocytes towards cSCC: Normal epidermis, solar elastosis, actinic keratosis KIN1-2, advanced actinic keratosis KIN3 and well-differentiated cSCC. Next-generation small RNA sequencing was performed. We found that 18 miRNAs are overexpressed and 28 miRNAs are underexpressed in cSCC compared to normal epidermis. miR-424, miR-320, miR-222 and miR-15a showed the highest fold change among the overexpressed miRNAs. And miR-100, miR-101 and miR-497 showed the highest fold change among the underexpressed miRNAs. Heat map of hierarchical clustering analysis of significantly changed miRNAs and principle component analysis disclosed that the most prominent change in miRNAs expression occurred in the switch from 'early' stages; normal epidermis, solar elastosis and early actinic keratosis to the 'late' stages of epidermal carcinogenesis; late actinic keratosis and cSCC. We found several miRNAs with 'stage specific' alterations while others display a clear 'gradual', either progressive increase or decrease in expression along the malignant evolution of keratinocytes. The observed alterations focused in miRNAs involved in the regulation of AKT/mTOR or in those involved in epithelial to mesenchymal transition. We chose to concentrate on the evaluation of the molecular role of miR-497. We found that it induces reversion of epithelial to mesenchymal transition. We proved that SERPINE-1 is its biochemical target. The present study allows us to further study the pathways that are regulated by miRNAs along the malignant evolution of keratinocytes towards cSCC.

Exosomal miRNAs and miRNA dysregulation in cancer-associated fibroblasts

Purpose

The present review aimed to assess the role of exosomal miRNAs in cancer-associated fibroblasts (CAFs), normal fibroblasts (NFs), and cancer cells. The roles of exosomal miRNAs and miRNA dysregulation in CAF formation and activation were summarized.

Methods

All relevant publications were retrieved from the PubMed database, with key words such as CAFs, CAF, stromal fibroblasts, cancer-associated fibroblasts, miRNA, exosomal, exosome, and similar terms.

Results

Recent studies have revealed that CAFs, NFs, and cancer cells can secrete exosomal miRNAs to affect each other. Dysregulation of miRNAs and exosomal miRNAs influence the formation and activation of CAFs. Furthermore, miRNA dysregulation in CAFs is considered to be associated with a secretory phenotype change, tumor invasion, tumor migration and metastasis, drug resistance, and poor prognosis.

Conclusions

Finding of exosomal miRNA secretion provides novel insights into communication among CAFs, NFs, and cancer cells. MicroRNA dysregulation is also involved in the whole processes of CAF formation and function. Dysregulation of miRNAs in CAFs can affect the secretory phenotype of the latter cells.

MicroRNA-148a deficiency promotes hepatic lipid metabolism and hepatocarcinogenesis in mice

miRNAs are involved in many physiologic and disease processes by virtue of degrading specific mRNAs or inhibiting their translation. miR-148a has been implicated in the control of tumor growth and cholesterol and triglyceride homeostasis using in vitro or in vivo gene expression- and silencing-based approaches. Here miR-148a knockout (KO) mice were used to investigate the intrinsic role of miR-148a in liver physiology and hepatocarcinogenesis in mice. miR-148a downregulation was found to be correlated with poor clinical outcomes in hepatocellular carcinoma (HCC) patients. Under regular chow diet (RCD) or high fat diet (HFD), miR-148a deletion significantly accelerated DEN-induced hepatocarcinogenesis in mice. Mechanistically, miR-148a deletion promotes lipid metabolic disorders in mice. Moreover, restoration of miR-148a reversed these defects. Finally, miR-148a was found to directly inhibit several key regulators of hepatocarcinogenesis and lipid metabolism. These findings reveal crucial roles for miR-148a in the hepatic lipid metabolism and hepatocarcinogenesis. They further identify miR-148a as a potential therapeutic target for certain liver diseases, including cancer.

The repressive effect of miR-148a on Wnt/β-catenin signaling involved in Glabridin-induced anti-angiogenesis in human breast cancer cells

Background

Glabridin (GLA), a major component extracted from licorice root, has anti-inflammatory and antioxidant activities, but few studies report its mechanism of inhibition of angiogenesis. This study was an extension of our previous work, which demonstrated that GLA suppressed angiogenesis in human breast cancer (MDA-MB-231 and Hs-578T) cells. Breast cancer is one of the most common malignant diseases in females worldwide, and the major cause of mortality is metastasis that is primarily attributed to angiogenesis. Thus, anti-angiogenesis has become a strategy for the treatment of breast cancer.

Methods

Cell viability of different concentration treatment groups were detected by Cell Counting Kit-8 assay. The expression of several related genes in the Wnt1 signaling pathway in MDA-MB-231 and Hs-578T cells treated with GLA were measured at both the transcription and translation levels using quantitative real-time PCR analyses and western blotting. Immunofluorescence assay analyzed the nuclear translocation of β-catenin. The microRNA-inhibitor was used to knockdown microRNA-148a (miR-148a) expression. Angiogenic potentials of breast cancer cells were analyzed by enzyme-linked immunosorbent assay (ELISA) and tube formation in vitro.

Results

GLA attenuated angiogenesis by the suppression of miR-148a-mediated Wnt/β-catenin signaling pathway in two human breast cancer cell lines (MDA-MB-231 and Hs-578T). GLA also upregulated the expression of miR-148a in a dose-dependent manner, miR-148a, which could directly target Wnt-3′-untranslated regions (UTRs), and decreased the expression of Wnt1, leading to β-catenin accumulation in the membranes from the cytoplasm and nucleus. Downregulation of miR-148a contributed to the reduction of GLA-induced suppression of the Wnt/β-catenin signaling pathway, the angiogenesis and vascular endothelial grow factor (VEGF) secretion.

Conclusions

Our study identified a molecular mechanism of the GLA inhibition of angiogenesis through the Wnt/β-catenin signaling pathway via miR-148a, suggesting that GLA could serve as an adjuvant chemotherapeutic agent for breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3298-1) contains supplementary material, which is available to authorized users.

miRNA-148a serves as a prognostic factor and suppresses migration and invasion through Wnt1 in non-small cell lung cancer

Lung cancer is the leading cause of cancer death in the world, and aberrant expression of miRNA is a common feature during the cancer initiation and development. Our previous study showed that levels of miRNA-148a assessed by quantitative real-time polymerase chain reaction (qRT-PCR) were a good prognosis factor for non-small cell lung cancer (NSCLC) patients. In this study, we used high-throughput formalin-fixed and paraffin-embedded (FFPE) lung cancer tissue arrays and in situ hybridization (ISH) to determine the clinical significances of miRNA-148a and aimed to find novel target of miRNA-148a in lung cancer. Our results showed that there were 86 of 159 patients with low miRNA-148a expression and miRNA-148a was significantly down-regulated in primary cancer tissues when compared with their adjacent normal lung tissues. Low expression of miRNA-148a was strongly associated with high tumor grade, lymph node (LN) metastasis and a higher risk of tumor-related death in NSCLC. Lentivirus mediated overexpression of miRNA-148a inhibited migration and invasion of A549 and H1299 lung cancer cells. Furthermore, we validated Wnt1 as a direct target of miRNA-148a. Our data showed that the Wnt1 expression was negatively correlated with the expression of miRNA-148a in both primary cancer tissues and their corresponding adjacent normal lung tissues. In addition, overexpression of miRNA-148a inhibited Wnt1 protein expression in cancer cells. And knocking down of Wnt-1 by siRNA had the similar effect of miRNA-148a overexpression on cell migration and invasion in lung cancer cells. In conclusion, our results suggest that miRNA-148a inhibited cell migration and invasion through targeting Wnt1 and this might provide a new insight into the molecular mechanisms of lung cancer metastasis.

MetastamiRs: A promising choice for antihepatocellular carcinoma nucleic acid drug development

Hepatocellular carcinoma (HCC) is the third leading cause of cancer mortality worldwide, which can be explained at least in part by its propensity towards metastasis and the limited efficacy of adjuvant therapy. MetastamiRs are miRNAs that promote or suppress migration and metastasis of cancer cells, and their functional status is significantly correlated with HCC prognosis. Unlike targeted therapy, metastamiRs have the potential to target multiple genes and signaling pathways and dramatically suppress cancer metastasis. In this review, we discuss the regulatory role of metastamiRs in the HCC invasion-metastasis cascade. Moreover, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis has shown that many extensively studied metastamiRs target several critical signaling pathways and these have remarkable therapeutic potential in HCC. The information reviewed here may assist in further anti-HCC miRNA drug screening and development.

CD90 a potential cancer stem cell marker and a therapeutic target

Cancer Stem Cells (CSCs) have been recently identified and their role in carcinogenesis has been ascertained. CSCs have been correlated with high relapse in certain cancers, multiple drug resistance against chemotherapy and metastasis. Several markers such as CD133, CD24, CD44, EpCAM, and CD26 have been identified to isolate and characterize CSCs. None of these markers or their combinations are universal in nature and can be used to isolate CSCs from all types of cancer. CD90 is one such marker whose expression has been extensively studied in recent years. CD90+ cells have been isolated from several types of tumors and shown to exhibit cardinal properties of CSCs such as proliferation, differentiation, spheroid formation, metastasis and ability to form tumor xenograft in immunodeficient mice. It is also found to be co-expressed with several other CSC markers. CD90 is therefore, suggested as a candidate marker as well as a potential therapeutic target for elimination of CSCs.

miR-148a-3p represses proliferation and EMT by establishing regulatory circuits between ERBB3/AKT2/c-myc and DNMT1 in bladder cancer

miR-148a-3p downregulation has emerged as a critical factor in cancer progression yet, the underlying mechanisms of miR-148a-3p expression pattern and its function in bladder cancer remains to be elucidated. Here, we illustrate that miR-148a-3p is frequently downregulated in bladder cancer and that its expression may be regulated by DNA methylation. DNA methyltransferase 1 (DNMT1) and miR-148a-3p function in a positive feedback loop in bladder cancer. miR-148a-3p overexpression functions as a tumor suppressor in bladder cancer cells. miR-148a-3p inhibits bladder cancer cell proliferation and epithelial–mesenchymal transition (EMT) by regulating ERBB3/AKT2/c-myc and ERBB3/AKT2/Snail signaling. ERBB3, DNMT1 and AKT2 are downstream miR-148a-3p target genes. Furthermore, the miR-148a-3p/ERBB3/AKT2/c-myc signaling axis establishes a positive feedback loop in the regulation of bladder cancer. Taken together, our study demonstrates novel regulatory circuits involving miR-148a-3p/ERBB3/AKT2/c-myc and DNMT1 that controls bladder cancer progression, which may be useful in the development of more effective therapies against bladder cancer.

MicroRNA-206 attenuates the growth and angiogenesis in non-small cell lung cancer cells by blocking the 14-3-3ζ/STAT3/HIF-1α/VEGF signaling

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality worldwide. Angiogenesis is the major hallmark in NSCLC. So, further elucidation of molecular mechanisms underlying the angiogenesis of NSCLC is urgently needed. Here, we found that microRNA-206 (miR-206) decreased the angiogenic ability in NSCLC via inhibiting the 14-3-3ζ/STAT3/HIF-1α/VEGF pathway. Briefly, 14-3-3ζ bond with phosphorylated-STAT3, and in turn, elevated the expression of HIF-1α. Then, by enhancing the recruitment of HIF-1α to VEGF promoter, 14-3-3ζ increased the angiogenesis. However, miR-206 decreased the angiogenesis by targeting 14-3-3ζ, and inhibiting the STAT3/HIF-1α/VEGF pathway. In NSCLC cell xenograft model, either overexpression of miR-206 or inhibition of 14-3-3ζ inhibited the STAT3/HIF-1α/VEGF pathway and decreased the tumor growth and angiogenesis. Furthermore, there was a negative correlation between miR-206 and 14-3-3ζ in NSCLC specimens. NSCLC patients with low expressions of miR-206 but high expressions of 14-3-3ζ had the worst survival. Collectively, our findings provided the underlying mechanisms of miR-206/14-3-3ζ in tumor growth and angiogenesis, and implicated miR-206 and 14-3-3ζ as potential therapeutic targets for NSCLC.

Induction of hepatocyte-like cells from human umbilical cord-derived mesenchymal stem cells by defined microRNAs

Generating functional hepatocyte‐like cells (HLCs) from mesenchymal stem cells (MSCs) is of great urgency for bio‐artificial liver support system (BALSS). Previously, we obtained HLCs from human umbilical cord‐derived MSCs by overexpressing seven microRNAs (HLC‐7) and characterized their liver functions in vitro and in vivo. Here, we aimed to screen out the optimal miRNA candidates for hepatic differentiation. We sequentially removed individual miRNAs from the pool and examined the effect of transfection with remainder using RT‐PCR, periodic acid—Schiff (PAS) staining and low‐density lipoprotein (LDL) uptake assays and by assessing their function in liver injury models. Surprisingly, miR‐30a and miR‐1290 were dispensable for hepatic differentiation. The remaining five miRNAs (miR‐122, miR‐148a, miR‐424, miR‐542‐5p and miR‐1246) are essential for this process, because omitting any one from the five‐miRNA combination prevented hepatic trans‐differentiation. We found that HLCs trans‐differentiated from five microRNAs (HLC‐5) expressed high level of hepatic markers and functioned similar to hepatocytes. Intravenous transplantation of HLC‐5 into nude mice with CCl₄‐induced fulminant liver failure and acute liver injury not only improved serum parameters and their liver histology, but also improved survival rate of mice in severe hepatic failure. These data indicated that HLC‐5 functioned similar to HLC‐7 in vitro and in vivo, which have been shown to resemble hepatocytes. Instead of using seven‐miRNA combination, a simplified five‐miRNA combination can be used to obtain functional HLCs in only 7 days. Our study demonstrated an optimized and efficient method for generating functional MSC‐derived HLCs that may serve as an attractive cell alternative for BALSS.

The Role of Mir-148a in Cancer

MicroRNAs (miRNAs) are highly conserved noncoding RNAs of about 19-25 nucleotides. Through specifically pairing with complementary sites in 3' untranslated regions (UTRs) of target mRNAs, they mediate post-transcriptional silencing. MicroRNAs have been implicated in many physiological processes including proliferation, differentiation, development, apoptosis, and metabolism. In recent years many studies have revealed that the aberrant expression of miRNA is closely related to oncogenesis and is now an intense field of study. Mir-148a is aberrantly expressed in various cancers and has been identified as an oncogenic or tumor suppressor with crucial roles in the molecular mechanisms of oncogenesis. In this review, we have summarized the role of mir-148a in the oncogenic pathways of gastric, liver, breast and urogenital cancers, and in neurogliocytoma oncogenesis. Studying the functional role of mir-148a is crucial in discovering novel tumor molecular markers and identifying potential therapeutic targets.

microRNA changes in liver tissue associated with fibrosis progression in patients with hepatitis C

BACKGROUND & AIMS

Accumulating evidence indicates that microRNAs play a role in a number of disease processes including the pathogenesis of liver fibrosis in hepatitis C infection. Our goal is to add to the accruing information regarding microRNA deregulation in liver fibrosis to increase our understanding of the underlying mechanisms of pathology and progression.

METHODS

We used next generation sequencing to profile all detectable microRNAs in liver tissue and serum from patients with hepatitis C, stages F1-F4 of fibrosis.

RESULTS

We found altered expression of several microRNAs, in particular, miR-182, miR199a-5p, miR-200a-5p and miR-183 were found to be significantly upregulated in tissue from liver biopsies of hepatitis C patients with advanced fibrosis, stage F3 and F4, when compared with liver biopsies from patients with early fibrosis, stages F1 and F2. We also found miR-148-5p, miR-1260b, miR-122-3p and miR-378i among the microRNAs most significantly down-regulated from early to advanced fibrosis of the liver. We also sequenced the serum microRNAs; however, we were not able to detect significant changes in circulating microRNAs associated with fibrosis stage after adjusting for multiple tests.

CONCLUSIONS

Adding measurements of tissue microRNAs acquired during routine biopsies will continue to increase our knowledge of underlying mechanisms of fibrosis. Our goal is that these data, in combination with studies from other researchers and future long-term studies, could be used to enhance the staging accuracy of liver biopsies and expand the surveillance of patients at increased risk for cancer and progression to advanced fibrosis.

Dysregulated miRNA in progression of hepatocellular carcinoma: A systematic review

Hepatocellular carcinoma (HCC) is the fifth most frequent cancer and the third cause of cancer-related mortality worldwide. The primary risk factor for HCC is liver cirrhosis secondary to persistent infection with hepatitis B virus or hepatitis C virus. Although a number of cellular phenomena and molecular events have been reported to facilitate tumor initiation, progression and metastasis, the exact etiology of HCC has not yet been fully uncovered. miRNA, a class of non-coding RNA, negatively regulate post-transcriptional processes that participate in crucial biological processes, including development, differentiation, apoptosis and proliferation. In the liver, specific miRNA can be negative regulators of gene expression. Recent studies have uncovered the contribution of miRNA to cancer pathogenesis as they can function as oncogenes or tumor suppressor genes. In addition, other studies have demonstrated their potential value in the clinical management of patients with HCC as some miRNA may be used as prognostic or diagnostic markers. In this review, we summarize the current knowledge about the roles of miRNA in the carcinogenesis and progression of HCC.

The PDGF-D/miR-106a/Twist1 pathway orchestrates epithelial-mesenchymal transition in gemcitabine resistance hepatoma cells

Emerging evidence demonstrates that platelet-derived growth factor-D (PDGF-D) plays a critical role in epithelial-mesenchymal transition (EMT) and drug resistance in hepatocellular carcinoma (HCC) cells. However, the underlying mechanism has not been fully elucidated. The objective is to explore the molecular mechanism of PDGF-D-mediated EMT in drug resistance HCC cells. To achieve our goal, we used multiple approaches including Western blotting, real-time RT-PCR, wound healing assay, invasion assay, luciferase activity assay, transfection, and immunohistochemistry. We found that PDGF-D is highly expressed in gemcitabine-resistant (GR) HCC cells. Moreover, PDGF-D markedly inhibited miR-106a expression and subsequently upregulated Twist1 expression. Notably, PDGF-D expression was associated with miR-106a and Twist1 in HCC patients. Our findings provide a possible molecular mechanism for understanding GR chemoresistance in HCC cells. Therefore, inactivation of PDGF-D/Twist or activation of miR-106a could be a novel strategy for the treatment of HCC.

MicroRNA-148a represents an independent prognostic marker in bladder cancer

A previous study has demonstrated the roles of microRNA-148a (miR-148a) on apoptosis of bladder cancer cells. The goal of this study was to investigate whether the miR-148a expression level could serve as a new biomarker for the prognosis of bladder cancer patients. We collected a total of 126 bladder cancer samples. The expression level of miR-148a was determined with quantitative real-time polymerase chain reaction (qRT-PCR). Kaplan-Meier method was used to analyze the overall survival. Cox regression analysis was further used to identify prognostic factors. The expression levels of miR-148a in bladder cancer tissues were identified (1.5 ± 0.3; P < 0.001). The bladder cancer patients in the low-expression group more frequently had a high tumor grade (P = 0.025), increased tumor recurrence (P = 0.002), and advanced lymph node (LN) metastasis (P = 0.001). Patient survival analysis revealed a clear positive correlation between miR-148a expression level and survival time of bladder cancer patients (P = 0.005, log-rank = 7.714). In univariate Cox proportional hazards regression analysis, we found that a low-expression level of miR-148a (P = 0.018), tumor grade (P = 0.006), lymph node metastasis (P = 0.001), and recurrence (P < 0.001) were associated with the prognosis of bladder cancer. In multivariate analysis, we found that miR-148a expression (RR = 0.206, 95 % CI 0.095-0.813, P = 0.029), tumor grade (RR = 0.714, 95 % CI 0.224-0.958, P = 0.714), lymph node metastasis (RR = 6.604, 95 % CI 3.192-12.547, P < 0.001), and recurrence (RR = 15.126, 95 % CI 6.714-22.025, P < 0.001) retained significance as an independent prognostic factor of bladder cancer survival (Table 3). All results have showed that miR-148a expression was decreased in bladder cancer specimens and reduced miR-148a expression was associated with poorer survival time, indicating that miR-148a may become a candidate factor for predicting the prognosis of bladder cancer.

MicroRNA-148a inhibits breast cancer migration and invasion by directly targeting WNT-1

Wnt/β-catenin signaling pathway influences embryonic development, cell polarity and adhesion, apoptosis and tumorigenesis. MicroRNAs (miRNAs) function as important regulators of the tumorigenesis and metastasis. In the present study, we aimed to find novel targets and mechanisms of microRNA-148a (miR-148a) in regulating the migration and invasion of breast cancer cells. In the present study, miR-148a was found downregulated in human breast cancer tissues and cell lines. The ectopic miR-148a expression inhibited the migration and invasion of MCF-7 and MDA-MB-231 breast cancer cells. Furthermore, we demonstrated that WNT-1, one of the ligands of Wnt/β-catenin signaling pathway, was a direct target of miR-148a. The overexpression of miR-148a reduced the mRNA and protein expression levels of WNT-1, also decreased the expression levels of the key components of Wnt/β-catenin pathway, including β-catenin, metalloproteinase-7 (MMP-7) and T-cell factor-4 (TCF-4) in MCF-7 and MDA-MB-231 cells. In addition, the data showed that the expression of WNT-1 was significantly higher in human breast cancer tissues compared with the adjacent normal tissues and the expression of miR-148a was negatively correlated with the WNT-1 expression in human breast cancer tissues. Taken together, our results suggest that miR-148a can suppress the migration and invasion of breast cancer cells by targeting WNT-1 and inhibiting Wnt/β-catenin signaling pathway and this will provide new insights into the molecular mechanisms of breast cancer metastasis.

Bioinformatics identification of potentially involved microRNAs in Tibetan with gastric cancer based on microRNA profiling

OBJECTIVE

The incidence of gastric cancer is high in Chinese Tibetan. This study aimed to identify the differentially expressed microRNAs (miRNAs) and further explore their potential roles in Tibetan with gastric cancer so as to predict potential therapeutic targets.

METHODS

A total of 10 Tibetan patients (male:female = 6:4) with gastric cancer were enrolled for isolation of matched gastric cancer and adjacent non-cancerous tissue samples. Affymetrix GeneChip microRNA 3.0 Array was employed for detection of miRNA expression in samples. Differential expression analysis between two sample groups was analyzed using Limma package. Then, MultiMiR package was used to predict targets for miRNAs. Following, the target genes were put into DAVID (Database for Annotation, Visualization and Integrated Discovery) to identify the significant pathways of miRNAs.

RESULTS

Using Limma package in R, a total of 27 differentially expressed miRNAs were screened out in gastric cancer, including 25 down-regulated (e.g. hsa-miR-148a-3p, hsa-miR-148b-3p and hsa-miR-363-3p) and 2 up-regulated miRNAs. According to multiMiR package, a number of 1445 target genes (e.g. Wnt1, KLF4 and S1PR1) of 13 differentially expressed miRNAs were screened out. Among those miRNAs, hsa-miR-148a-3p, hsa-miR-148b-3p and hsa-miR-363-3p were identified with the most target genes. Furthermore, three miRNAs were significantly enriched in numerous common cancer-related pathways, including "Wnt signaling pathway", "MAPK signaling pathway" and "Jak-STAT signaling pathway".

CONCLUSIONS

The present study identified a downregulation and enrichment in cancer-related pathways of hsa-miR-148a-3p, hsa-miR-148b-3p and hsa-miR-363-3p in Tibetan with gastric cancer, which can be suggested as therapeutic targets.

Circulating miR-148/152 family as potential biomarkers in hepatocellular carcinoma

Aberrant expressions of the miR-148/152 family (miR-148a, miR-148b, and miR-152) have been documented in many tumor tissues, including hepatocellular carcinoma (HCC). However, the expression pattern and clinical significance of circulating miR-148/152 family in HCC remain elusive. In this study, we conducted quantitative real-time polymerase chain reaction (qRT-PCR) to examine the levels of serum miR-148a, miR-148b, and miR-152 in 76 HCC cases, as well as 62 controls with benign liver diseases and 55 healthy volunteers. Our results showed that serum levels of three microRNAs (miRNAs) were significantly decreased in HCC cases than those in benign and healthy controls (all P < 0.05). Moreover, they showed strong correlations with each other in HCC group (r = 0.6716, 0.5381, and 0.7712; all P < 0.001). Receiver operating characteristic (ROC) analysis revealed that the combination of circulating miR-148/152 family had an increased area under the curve (AUC) = 0.940 (95 % confidence interval (CI), 0.886-0.973) with the sensitivity of 96.1 % and the specificity of 91.9 %, which were significantly higher than those of serum alpha-fetoprotein (AFP) and three miRNAs alone in differentiating HCC from benign liver diseases. In addition, serum miR-148a and miR-148b were significantly associated with tumor size (P = 0.011 and 0.037) and tumor-node-metastasis (TNM) stage (P < 0.001 and P = 0.034), yet serum miR-152 was only correlated with TNM stage (P = 0.009). Also, dynamic monitoring three miRNAs can help us predict recurrence or metastasis in HCC cases after surgical resection. Besides, Kaplan-Meier analyses demonstrated that the decreased serum miR-148a (P < 0.001) and miR-152 (P = 0.012) was closely correlated with shorten overall survival of HCC patients. Additionally, Cox regression model further indicated that serum miR-148a was strongly associated with the prognosis of HCC patients. Our study suggests that downregulated circulating miR-148/152 family can provide positive diagnostic value for HCC. Moreover, serum miR-148a might be as independent prognostic factor for HCC patients.

Advances in differentiation therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignancy of the digestive system, which shows obvious disorders of differentiation. Currently, its pathogenesis is still elusive. Therefore, to figure out the mechanism of disturbed differentiation in HCC is the key to finding out precise therapeutic targets for differentiation therapy. Differentiation therapy of hepatocellular carcinoma refers to making hepatocellular carcinoma cells differentiate into mature hepatocytes, and rebuilding their normal phenotype and normal biological function through promoting HCC cell apoptosis and inhibiting their proliferation in the presence of specific differentiation-inducing agents or signals. In recent years, increasing research results about HCC differentiation therapy have been reported. This article reviews differentiation-inducing agents or targets, differentiation-related signaling pathways and microRNAs, with an aim to provide some clues for HCC differentiation therapy.

MicroRNA-148a inhibits migration of breast cancer cells by targeting MMP-13

Breast cancer is a threat to the health of women, and metastasis of breast cancer cells plays an important role in the deterioration of breast cancer. MicroRNAs play a critical role in the tumorigenesis and development of breast cancer. MicroRNA-148a (miR-148a) is associated with the growth and metastasis of tumor cells. In the present study, we investigated the role of miR-148a in migration of breast cancer cells as well as the underlying mechanism. MiR-148a was found to inhibit the proliferation and migration of breast cancer cells. To further explore the mechanism through which miR-148a plays its antitumor role, matrix metalloproteinase-13 (MMP-13) was identified as a target of miR-148a by western blot and luciferase reporter assay. Moreover, silence of MMP-13 mimicked the effect of miR-148a, whereas overexpression of MMP-13 rescued the impaired migration caused by miR-148a. Our study demonstrates that miR-148a inhibits the migration of breast cancer cells by targeting MMP-13 and also lays theoretical foundation for further exploration for the function of miR-148a.

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

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

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CaA inhibits the activity/expression of SMAD2.

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

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

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

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