Molecular mechanisms governing microRNA-125a expression in human hepatocellular carcinoma cells

Potential roles of exosomes in the initiation and metastatic progression of lung cancer

Lung cancer (LC) incidence and mortality continue to increase annually worldwide. LC is insidious and readily metastasizes and relapses. Except for its early diagnosis and surgical resection, there is no effective cure for advanced metastatic LC, and the prognosis remains dismal. Exosomes, a class of nano-sized extracellular vesicles produced by healthy or diseased cells, are coated with a bilayer lipid membrane and contain various functional molecules such as proteins, lipids, and nucleic acids. They can be used for intracellular or intercellular signaling or the transportation of biological substances. A growing body of evidence supports that exosomes play multiple crucial roles in the occurrence and metastatic progression of many malignancies, including LC. The elucidation of the potential roles of exosomes in the initiation, invasion, and metastasis of LC and their underlying molecular mechanisms may contribute to improved early diagnosis and treatment.

Prognostic value of microRNA-125a expression status in molecular groups of pediatric medulloblastoma

PURPOSE

Medulloblastoma (MB) is the most common malignant pediatric brain tumor. Current treatment allows decent survival rates but often with life-long morbidity. Molecular classification provides a base for novel therapeutic approaches. However, these groups are heterogeneous. MicroRNA-125a has a tumor suppressor function. It is downregulated in several tumors. The expression of microRNA-125a in MB patients remains unclear. Therefore, this study was designed to evaluate the expression of microRNA-125a in molecular groups of pediatric MB patients in Egyptian population and its clinical significance.

METHODS

Formalin-fixed, paraffin-embedded tissue blocks from 50 pediatric MB patients were retrospectively collected. Immunohistochemistry for β-catenin, GAB1, YAP1, and p53 was done for molecular classification. MicroRNA-125a expression analysis was done using qRT-PCR. Follow-up data were obtained from patients' records.

RESULTS

MicroRNA-125a expression was significantly lower in MB patients showing large cell/anaplastic (LC/A) histology and in the non-WNT/non-SHH group. Lower levels of microRNA-125a showed a tendency toward poor survival rates; however, difference was not significant. Infants and larger preoperative tumor size were significantly associated with lower survival rates. On a multivariate analysis, preoperative tumor size was an independent prognostic factor.

CONCLUSION

MicroRNA-125a expression was significantly lower in categories of pediatric MB patients with worse prognosis namely LC/A histology and the non-WNT/non-SHH group suggesting a pathogenetic role. MicroRNA-125a expression could represent a promising prognostic factor and a potential therapeutic target in the non-WNT/non-SHH group which represents the most common and the most heterogeneous group of pediatric MBs coupled with the highest rates of disseminated disease. Preoperative tumor size represents an independent prognostic factor.

Equine mesenchymal stem cell derived extracellular vesicle immunopathology biomarker discovery

The use of mesenchymal stem cells (MSCs) in human and veterinary clinical applications has become a subject of increasing importance due to their roles in immunomodulation and regenerative processes. MSCs are especially relevant in equine medicine because they may have the ability to treat prevalent musculoskeletal disorders, among other conditions. However, recent evidence suggests that the components secreted by MSCs, particularly extracellular vesicles (EVs), are responsible for these properties. EVs contain proteins and nucleic acids, which possess an active role in intercellular communication and can be used as therapeutics. However, because the intersection of equine veterinary medicine with EVs remains a relatively new field, there is a demand to identify biomarkers that can discern and enrich for therapeutic EVs, progressing their clinical efficacy. In this study, we identified and characterized 84 miRNAs, between three equine donors involved in immunomodulation in cell and EV subjects. We discovered distinct groups of shared miRNAs, like miR-21-5p and miR-451a, that are abundant and enriched between the donors' EVs, respectively. By mapping and comparing the MSC-EV miRNA expression, we discovered many pathways that are involved in immunomodulation and tissue regenerative processes related to equine clinical applications. Therefore, the miRNAs highlighted in this article can be used as valuable biomarkers for screening MSC-derived EVs for potential equine therapy.

Role of sirtuins in hepatocellular carcinoma progression and multidrug resistance: Mechanistical and pharmacological perspectives

Hepatocellular carcinoma (HCC) is the third most common cause of death from cancer worldwide. Therapeutic strategies are still challenging due to the high relapse rate after surgery and multidrug resistance (MDR). It is essential to better understand the mechanisms for HCC progression and MDR for the development of new therapeutic strategies. Mammalian sirtuins (SIRTs), a family of seven members, are related to tumor progression, MDR and prognosis and were proposed as potential prognostic markers, as well as therapeutic targets for treating cancer. SIRT1 is the most studied member and is overexpressed in HCC, playing an oncogenic role and predicting poor prognosis. Several manuscripts describe the role of SIRTs2-7 in HCC; most of them report an oncogenic role for SIRT2 and -7 and a suppressive role for SIRT3 and -4. The scenario is more confusing for SIRT5 and -6, since information is contradictory and scarce. For SIRT1 many inhibitors are available and they seem to hold therapeutic promise in HCC. For the other members the development of specific modulators has just started. This review is aimed to describe the features of SIRTs1-7 in HCC, and the role they play in the onset and progression of the disease. Also, when possible, we will depict the information related to the SIRTs modulators that have been tested in HCC and their possible implication in MDR. With this, we hope to clarify the role of each member in HCC and to shed some light on the most successful strategies to overcome MDR.

Replication of association at the LPP and UBASH3A loci in a UK autoimmune Addison's disease cohort

Autoimmune Addison's disease (AAD) arises from a complex interplay between multiple genetic susceptibility polymorphisms and environmental factors. The first genome wide association study (GWAS) with patients from Scandinavian Addison's registries has identified association signals at four novel loci in the genes LPP, SH2B3, SIGLEC5, and UBASH3A. To verify these novel risk loci, we performed a case-control association study in our independent cohort of 420 patients with AAD from the across the UK. We report significant association of alleles of the LPP and UBASH3A genes [odds ratio (95% confidence intervals), 1.46 (1.21-1.75)and 1.40 (1.16-1.68), respectively] with AAD in our UK cohort. In addition, we report nominal association of AAD with SH2B3 [OR 1.18 (1.02-1.35)]. We confirm that variants at the LPP and UBASH3A loci confer susceptibility to AAD in a UK population. Further studies with larger patient cohorts are required to robustly confirm the association of SH2B3 and SIGLEC5/SPACA6 alleles.

Histone deacetylase HDAC2 regulates microRNA-125a expression in neuroblastoma

BACKGROUND

Neuroblastoma (NB) is an infrequent childhood malignancy of the peripheral sympathetic nervous system and is accountable for about 10% of pediatric tumors. microRNA (miR)-125a has been implicated to serve as a tumor suppressor in various cancers. Herein, we set out to ascertain whether miR-125a exerts antitumor effects in NB.

METHODS

Downregulated miRNAs were identified by miRNA microarray analysis of NB tissues and paracancerous tissues. The expression of miR-125a in NB tissues and cells was detected by reverse transcription-quantitative (RT-q) PCR, followed by prognostic analysis. Gene Ontology (GO) enrichment analysis was performed on target genes of differentially expressed miRNAs. Cell proliferation, apoptosis, and differentiation were detected by cell counting kit-8 (CCK-8), Hoechst staining, immunofluorescence, and western blot. NB cells were injected into nude mice to detect tumorigenic, apoptotic, and differentiation activities in vivo. Dual-luciferase assay and chromatin immunoprecipitation (ChIP) were carried out to verify the binding relationship between miR-125a and PHOX2B or histone deacetylases 2 (HDAC2), respectively. Finally, rescue experiments were conducted.

RESULTS

miR-125a was downregulated in NB tissues and cells, which was associated with poor prognosis. miR-125a reduced NB cell proliferation and augmented apoptosis and differentiation. NB cells with miR-125a overexpression decreased cell tumorigenesis and increased apoptosis and differentiation in xenograft tumor tissues. miR-125a targeted PHOX2B, which was highly expressed in NB tissues and cells. HDAC2, highly expressed in NB tissues and cells, repressed miR-125a transcription through histone deacetylation. Overexpression of HDAC2 or PHOX2B rescued the effects of miR-125a on NB cell proliferation, apoptosis, and differentiation.

CONCLUSION

HDAC2 inhibited miR-125a transcription through deacetylation, and miR-125a suppressed NB development through binding to PHOX2B.

Chromatin accessibility and microRNA expression in nephron progenitor cells during kidney development

Mammalian nephrons originate from a population of nephron progenitor cells, and changes in these cells' transcriptomes contribute to the cessation of nephrogenesis, an important determinant of nephron number. To characterize microRNA (miRNA) expression and identify putative cis-regulatory regions, we collected nephron progenitor cells from mouse kidneys at embryonic day 14.5 and postnatal day zero and assayed small RNA expression and transposase-accessible chromatin. We detect expression of 1104 miRNA (114 with expression changes), and 46,374 chromatin accessible regions (2103 with changes in accessibility). Genome-wide, our data highlight processes like cellular differentiation, cell migration, extracellular matrix interactions, and developmental signaling pathways. Furthermore, they identify new candidate cis-regulatory elements for Eya1 and Pax8, both genes with a role in nephron progenitor cell differentiation. Finally, we associate expression-changing miRNAs, including let-7-5p, miR-125b-5p, miR-181a-2-3p, and miR-9-3p, with candidate cis-regulatory elements and target genes. These analyses highlight new putative cis-regulatory loci for miRNA in nephron progenitors.

Micro-RNA-125a mediates the effects of hypomethylating agents in chronic myelomonocytic leukemia

BACKGROUND

Chronic myelomonocytic leukemia (CMML) is an aggressive hematopoietic malignancy that arises from hematopoietic stem and progenitor cells (HSPCs). Patients with CMML are frequently treated with epigenetic therapeutic approaches, in particular the hypomethylating agents (HMAs), azacitidine (Aza) and decitabine (Dec). Although HMAs are believed to mediate their efficacy via re-expression of hypermethylated tumor suppressors, knowledge about relevant HMA targets is scarce. As silencing of tumor-suppressive micro-RNAs (miRs) by promoter hypermethylation is a crucial step in malignant transformation, we asked for a role of miRs in HMA efficacy in CMML.

RESULTS

Initially, we performed genome-wide miR-expression profiling in a Kras^G12D-induced CMML mouse model. Selected candidates with prominently decreased expression were validated by qPCR in CMML mice and human CMML patients. These experiments revealed the consistent decrease in miR-125a, a miR with previously described tumor-suppressive function in myeloid neoplasias. Furthermore, we show that miR-125a downregulation is caused by hypermethylation of its upstream region and can be reversed by HMA treatment. By employing both lentiviral and CRISPR/Cas9-based miR-125a modification, we demonstrate that HMA-induced miR-125a upregulation indeed contributes to mediating the anti-leukemic effects of these drugs. These data were validated in a clinical context, as miR-125a expression increased after HMA treatment in CMML patients, a phenomenon that was particularly pronounced in cases showing clinical response to these drugs.

CONCLUSIONS

Taken together, we report decreased expression of miR-125a in CMML and delineate its relevance as mediator of HMA efficacy within this neoplasia.

A Novel ceRNA Regulatory Network Involving the Long Non-Coding Antisense RNA SPACA6P-AS, miR-125a and its mRNA Targets in Hepatocarcinoma Cells

MicroRNAs (miRNA), and more recently long non-coding RNAs (lncRNA), are emerging as a driving force for hepatocellular carcinoma (HCC), one of the leading causes of cancer-related death. In this work, we investigated a possible RNA regulatory network involving two oncosuppressive miRNAs, miR-125a and let-7e, and a long non-coding antisense RNA, SPACA6P-AS (SP-AS), all transcribed from the same locus, with SP-AS in the opposite direction and thus carrying complementary sequences to the miRNAs. In vitro experiments validated the binding of the miRNAs to SP-AS. Then, the boosting of either the miRNAs or SP-AS levels demonstrated their reciprocal inhibition. In addition, overexpression of SP-AS resulted in a reduced silencing activity of miR-125a and let-7e toward their key oncogenic targets, i.e., Lin28b, MMP11, SIRT7, Zbtb7a, Cyclin D1, CDC25B, HMGA2, that resulted significantly upregulated. Finally, the analysis of 374 HCC samples in comparison to 50 normal liver tissues showed an upregulation of SP-AS and a reverse expression of miR-125a, not observed for let-7e; consistently, miR-125a oncogenic targets were upregulated. Overall, the data depict a novel competing endogenous RNA (ceRNA) network, ceRNET, whereby miR-125a can regulate the expression of SP-AS, which in turn regulates the miRNA by competing with the binding to the mRNA targets. We speculate that the unbalancing of any network component may contribute to hepatocarcinogenesis.

Long Non-coding RNA MRUL Contributes to Osteosarcoma Progression Through the miR-125a-5p/FUT4 Axis

Osteosarcoma (OS) originates in the skeletal system and has a rising global incidence. Long Non-coding RNAs (lncRNAs) are key regulators of human cancers development and progression. However, their roles in the development of OS are not well understood. This research aimed to investigate the effect of a long non-coding RNA (lncRNA), MRUL, on OS and revealed its potential molecular mechanisms. The bioinformatics analysis demonstrated that lncRNA MRUL was involved in regulating nucleic acid-templated transcription, cellular macromolecule biosynthetic process, immune response, and inflammatory response. In this work, the expression of lncRNA MRUL was detected by quantitative real-time polymerase chain reaction (qRT-RCR) in both cancer tissues and cell lines. We found that lncRNA MRUL was up-regulated in cancer tissues and cell lines. Functional experiments showed that knockdown of lncRNA MRUL inhibited OS cell proliferation, and metastasis. At the same time, we found that lncRNA MRUL interacted with miR-125a-5p to suppress FUT4 expression. Moreover, inhibition of miR-125a-5p abrogated the biological roles of lncRNA MRUL knockdown on OS cell proliferation, migration, and invasion. In conclusion, these results demonstrated that OS-upregulated lncRNA MRUL promoted cell proliferation, and metastasis via negatively regulating miR-125a-5p, and imply that lncRNA MRUL may be a potential biomarker for OS.

Proto-oncogene Zbtb7a represses miR-125a-5p transcription in hepatocellular carcinoma cells

Zbtb7a is a transcription factor whose dysfunction is correlated to the development of several types of cancer, including hepatocellular carcinoma (HCC). It generally acts as a repressor of transcription downregulating the expression of several target genes including oncosuppressors ARF and Rb. In this study, Zbtb7a was found to suppress the expression of miR-125a, an oncosuppressive miRNA that is often downregulated in HCC. This effect is mediated by the binding of the transcription factor to a regulatory sequence in the promoter of the transcription unit of miR-125a located 14 bp upstream of the transcription start site. Consistent with this observation, the analysis of 370 HCC samples showed an upregulation of Zbtb7a compared to 50 normal liver tissues and a reverse correlation with miR-125a expression. These data suggest that miR-125a may support the oncogenic potential of Zbtb7a.

Circular RNA MAPK4 (circ-MAPK4) inhibits cell apoptosis via MAPK signaling pathway by sponging miR-125a-3p in gliomas

Background

Recent evidences have shown that circular RNAs (circRNAs) are frequently dysregulated and play paramount roles in various cancers. circRNAs are abundant in central nervous system (CNS); however, few studies describe the clinical significance and role of circRNAs in gliomas, which is the most common and aggressive primary malignant tumor in the CNS.

Methods

A bioinformatics analysis was performed to profile and screen the dyregulated circRNAs during early neural development. Quantitative real-time PCR was used to detect the expression of circ-MAPK4 and target miRNAs. Glioma cells were transfected with circ-MAPK4 siRNAs, then cell proliferation, apoptosis, transwell assays, as well as tumorigenesis and TUNEL assays, were performed to examine effect of circ-MAPK4 in vitro and vivo. Biotinylated-circ-MAPK4 probe based pull-down assay was conducted to confirm the relationship between circ-MAPK4 and miR-125-3p.

Results

In this study, we identified a circRNA, circ-MAPK4 (has_circ_0047688), which was downregulated during early neural differentiation. In gliomas, circ-MAPK4 acted as an oncogene, was inversely upregulated and linked to clinical pathological stage of gliomas (P < 0.05). Next, we verified that circ-MAPK4 promoted the survival and inhibited the apoptosis of glioma cells in vitro and in vivo. Furthermore, we proved that circ-MAPK4 was involved in regulating p38/MAPK pathway, which affected glioma proliferation and apoptosis. Finally, miR-125a-3p, a miRNA exhibited tumor-suppressive function through impairing p38/MAPK pathway, which was increased by inhibiting circ-MAPK4 and could be pulled down by circ-MAPK4. Inhibition of miR-125a-3p could partly rescue the increased phosphorylation levels of p38/MAPK and the elevated amount of apoptosis inducing by knockdown of circ-MAPK4.

Conclusions

Our findings suggest that circ-MAPK4 is a critical player in glioma cell survival and apoptosis via p38/MAPK signaling pathway through modulation of miR-125a-3p, which can serve as a new therapeutic target for treatment of gliomas.

Genome-wide miRNA profiling and pivotal roles of miRs 125a-5p and 17-92 cluster in human neutrophil maturation and differentiation of acute myeloid leukemia cells

MicroRNAs (miRNAs, miRs) are short non-coding post-transcriptional regulators of gene expression in normal physiology and disease. Acute myeloid leukemia is characterized by accumulation of malignantly transformed immature myeloid precursors, and differentiation therapy, used to overcome this differentiation blockage, has become a successful therapeutic option. The human HL-60 acute leukemia cell line serves as a cell culture model for granulocytic maturation, and dimethyl sulfoxide (DMSO) incubation leads to its differentiation towards neutrophil-like cells, as assessed by biochemical, functional and morphological parameters. DMSO-induced HL-60 cell differentiation constitutes an excellent model to examine molecular processes that turn a proliferating immortal leukemic cell line into mature non-proliferating and apoptosis-prone neutrophil-like end cells. By performing genome-wide miRNA profiling and functional assays, we have identified a signature of 86 differentially expressed canonical miRNAs (51 upregulated; 35 downregulated) during DMSO-induced granulocytic differentiation of HL-60 cells. Quantitative real-time PCR was used to validate miRNA expression. Among these differentially expressed canonical miRNAs, we found miR-125a-5p upregulation and miR-17-92 cluster downregulation acted as major regulators of granulocytic differentiation in HL-60 cells. Enforced expression of miR-125a-5p promoted granulocytic differentiation in HL-60 cells, whereas miR-17-92 ectopic expression inhibited DMSO-induced HL-60 granulocytic differentiation. Ectopic expression of miR-125a-5p also promoted granulocytic differentiation in human acute promyelocytic leukemia NB4 cells, as well as in naïve human primary CD34⁺-hematopoietic progenitor/stem cells. These findings provide novel molecular insights into the identification of miRNAs regulating granulocytic differentiation of human leukemia cells and normal CD34⁺-hematopoietic progenitor/stem cells, and may assist in the development of novel miRNA-targeted therapies for leukemia.

miR-125a-5p: a novel regulator of SLC26A6 expression in intestinal epithelial cells

Putative anion transporter 1 (PAT1, SLC26A6), an intestinal epithelial Cl^-/ HCO3- exchanger, also plays a key role in oxalate homeostasis via mediating intestinal oxalate secretion. Indeed, Slc26a6-null mice showed defect in intestinal oxalate secretion and high incidence of kidney stones. Recent emergence of PAT-1 as a novel therapeutic target for nephrolithiasis warrants detailed understanding of the mechanisms of PAT-1 regulation in health and disease. Therefore, we investigated the regulation of PAT-1 expression by microRNAs (miRNA), as they have been shown to play key role in modulating expression of other ion transporters. In silico analysis of PAT-1 3'-untranslated region (UTR) revealed potential binding sites for several miRNAs, suggesting the role of miRNAs in modulating PAT1 expression. miRNAs showing highest context scores (125a-5p, 339-5p, 423-5p, 485-5p, and 501-3p) were selected as candidates for their effects on the activity of a 263-bp PAT-1 3'-untranslated region (UTR) fragment cloned into pmirGLO vector upstream of luciferase. The 3'-UTR activity was measured by dual luciferase reporter assay in Caco-2, T-84, HT-29, and SK-CO15 cells. Transient transfection of PAT-1 3'-UTR significantly decreased the relative luciferase activity compared with the empty vector suggesting binding of potential miRNA(s) to the PAT-1 3'-UTR. Among all the selected candidates, cotransfection with miRNA mimics 125a-5p and 423-5p further decreased PAT-1 3'-UTR activity. Furthermore, increasing miR-125a-5p abundance via mimic transfection in Caco-2 cells decreased both mRNA and protein levels of PAT-1. Our results demonstrate a novel regulatory mechanism of intestinal PAT-1 expression via miR-125a-5p that could be of therapeutic importance in disorders associated with decreased PAT-1 expression and function.

Antiproliferative Activity of microRNA-125a and its Molecular Targets

BACKGROUND

MicroRNA-125a is present in all animals with bilateral symmetry and displays a conserved nucleotide sequence with a section of 11 bases including the seed region that is identical in all considered species. It primarily downregulates the expression of LIN28, thereby promoting cell differentiation and larval phase transitions in nematodes, mammals and insects.

OBJECTIVE

In this review, we focus on the cellular control of miR-125a expression and its antiproliferative activity.

RESULTS

In mammalians, microRNA-125a is present in most adult organs and tissues in which it targets proteins involved in the mitogenic response, such as membrane receptors, intracellular signal transducers, or transcription factors, with the overall effect of inhibiting cell proliferation. Tissue levels of miR-125a generally raise during differentiation but it is often downregulated in cancers, e.g. colon, cervical, gastric, ovarian, lung, and breast cancers, osteosarcoma, neuroblastoma, glioblastoma, medulloblastoma, retinoblastoma and hepatocellular carcinoma.

CONCLUSION

The antiproliferative activity of miR-125a, demonstrated in many cell types, together with the notion that this miRNA is downregulated in several kinds of cancers, give a substantial support to the concept that miR-125a plays an oncosuppressive role.

miR-125a Promotes the Progression of Giant Cell Tumors of Bone by Stimulating IL-17A and β-Catenin Expression

Giant cell tumors of bone (GCTBs) exhibit high recurrence and aggressive bone lytic behavior; but, the mechanism of GCTB progression is largely unknown. In GCTB, we detected abundant levels of miR-125a, which were associated with tumor extension, grade, and recurrence. miR-125a stimulates stromal cell tumorigenicity and growth in vivo by promoting the expression of interleukin-17A (IL-17A) and β-catenin. In contrast, inhibition of miR-125a suppressed stromal cell tumorigenicity and growth. Then, we found that miR-125a stimulates IL-17A by targeting TET2 and Foxp3, and it stimulates β-catenin expression by targeting APC and GSK3β in stromal cells. Furthermore, we identified that IL-17A stimulates miR-125a by activating nuclear factor κB (NF-κB) signaling in stromal cells. Finally, our data show that simultaneous inhibition of IL-17A signaling and miR-125a more significantly inhibits stromal cell growth than miR-125a inhibition alone. miR-125a stimulates the progression of GCTB, and it might represent a useful candidate marker for progression. Simultaneously blocking miR-125a and IL-17A might represent a new therapeutic strategy for GCTB.

Micro-RNAs in hepatitis B virus-related chronic liver diseases and hepatocellular carcinoma

MicroRNAs (miRNAs) are small non-coding RNAs that modulate gene expression at the post-transcriptional level by affecting both the stability and translation of complementary mRNAs. Several studies have shown that miRNAs are important regulators in the conflicting efforts between the virus (to manipulate the host for its successful propagation) and the host (to inhibit the virus), culminating in either the elimination of the virus or its persistence. An increasing number of studies report a role of miRNAs in hepatitis B virus (HBV) replication and pathogenesis. In fact, HBV is able to modulate different host miRNAs, particularly through the transcriptional transactivator HBx protein and, conversely, different cellular miRNAs can regulate HBV gene expression and replication by a direct binding to HBV transcripts or indirectly targeting host factors. The present review will discuss the role of miRNAs in the pathogenesis of HBV-related diseases and their role as a biomarker in the management of patients with HBV-related disease and as therapeutic targets.

Correlation Between the Hepatic Expression of Human MicroRNA hsa-miR-125a-5p and the Progression of Fibrosis in Patients With Overt and Occult HBV Infection

Aims

To evaluate the correlation between the hepatic expression pattern of hsa-miR-125a-5p and HBV-DNA and the progression of fibrosis in patients with overt or occult HBV infection.

Methods

We enrolled all the HBsAg-positive treatment naive patients (overt HBV group) and all the HBsAg-negative patients with hepatocellular carcinoma and with a positive HBV-DNA in their hepatic tissue (occult HBV group), who underwent a diagnostic liver biopsy between April 2007 and April 2015. Tissue concentrations of HBV-DNA and hsa-miR-125a-5p were then analyzed by real-time quantitative PCR. Necroinflammatory activity and fibrosis were evaluated according to the Ishak score.

Results

During the study period, we enrolled 64 patients with overt and 10 patients with occult HBV infection. In the overt HBV group, 35 of 64 (54.7%) showed a mild fibrosis (staging 0–2), 17 (26.6%) a moderate fibrosis (staging 3–4), while the remaining 12 (18.7%) had a cirrhosis. All patients in the occult HBV group were cirrhotic. Patients with more advanced fibrosis stage showed a higher mean age when compared with those with mild (p < 0.00001) or moderate fibrosis (p < 0.00001) and were more frequently male than patients with staging 0–2 (p = 0.04). Similarly, patients with occult B infection were older than HBsAg-positive patients. Liver concentrations of miR-125a-5p were significantly higher in patients with cirrhosis (9.75 ± 4.42 AU) when compared with patients with mild (1.39 ± 0.94, p = 0.0002) or moderate fibrosis (2.43 ± 2.18, p = 0.0006) and were moderately higher in occult than in overt HBV infection (p = 0.09). Moreover, we found an inverse correlation, although not statistically significant, between the tissue HBV-DNA levels and the staging of fibrosis.

Conclusion

This study suggests a correlation between the tissue expression of hsa-miR-125a-5p and the progression of liver damage in a group of patients with occult or overt HBV infection. If confirmed, these data suggest the hsa-miR-125a-5p may be a novel biomarker of hepatic damage.

MiR-23a transcriptional activated by Runx2 increases metastatic potential of mouse hepatoma cell via directly targeting Mgat3

MicroRNAs (miRNAs) and aberrant glycosylation both play important roles in tumor metastasis. In this study, the role of miR-23a in N-glycosylation and the metastasis of mouse hepatocellular carcinoma (HCC) cells was investigated. The miRNA expression array profiles that were confirmed by qPCR and Western blot analyses revealed higher miR-23a expression levels in Hca-P cells (with lymphatic metastasis potential) than in Hepa1-6 cells (with no lymphatic metastasis potential), while the expression of mannoside acetylglucosaminyltransferase 3 (Mgat3) was negatively associated with metastasis potential. Mgat3 is a key glycosyltransferase in the synthesis of the bisecting (β1,4GlcNAc branching) N-glycan structure. Bioinformatics analysis indicated that Mgat3 may be a target of miR-23a, and this hypothesis was verified by dual-luciferase reporter gene assays. Furthermore, we found that the transcription factor Runx2 can directly bind to the miR-23a gene promoter and promote its expression, as shown in dual-luciferase reporter gene assays and ChIP assays. Collectively, these results indicate that miR-23a might increase the metastatic potential of mouse HCC by affecting the branch formation of N-glycan chains presented on the cell surface through the targeting of the glycosyltransferase Mgat3. These findings may provide insight into the relationship between abnormal miRNA expression and aberrant glycosylation during tumor lymphatic metastasis.

Mutual suppression of miR-125a and Lin28b in human hepatocellular carcinoma cells

MicroRNA-125a exhibits an antiproliferative activity and is downregulated in several types of tumors, including hepatocellular carcinoma where it targets sirtuin-7, matrix metalloproteinase-11, and c-Raf. Another target of miR-125a is Lin28, a pluripotency factor that is generally undetectable in differentiated cells but is often upregulated/reactivated in tumors where it acts as an oncogenic factor promoting cell proliferation and tumor progression. In this study we show that downregulation of Lin28b by miR-125a partially accounts for its antiproliferative activity toward hepatocellular carcinoma cells. We also found that Lin28b is able to bind a conserved GGAG motif of pre-miR-125a and to inhibit its maturation in hepatocellular carcinoma cells. Reciprocal inhibition between miR-125a and Lin28b reasonably generates a positive feedback loop where reactivation of Lin-28b inhibits the expression of both miR-125a and let-7, reinforcing its own expression and leading to a marked overexpression of the mitogenic targets of the two miRNAs. On the other hand, perturbation of these circuits by overexpression of miR-125a suppresses Lin28b leading to a decreased cell proliferation. Overall, these data support a tumor suppressive role for miR-125a and contribute to the elucidation of its molecular targets.