Strong inverse correlation between microRNA-125b and human papillomavirus DNA in productive infection

The microRNA Let-7 and its exosomal form: Epigenetic regulators of gynecological cancers

Many types of gynecological cancer (GC) are often silent until they reach an advanced stage, and are therefore often diagnosed too late for effective treatment. Hence, there is a real need for more efficient diagnosis and treatment for patients with GC. During recent years, researchers have increasingly studied the impact of microRNAs cancer development, leading to a number of applications in detection and treatment. MicroRNAs are a particular group of tiny RNA molecules that regulate regular gene expression by affecting the translation process. The downregulation of numerous miRNAs has been observed in human malignancies. Let-7 is an example of a miRNA that controls cellular processes as well as signaling cascades to affect post-transcriptional gene expression. Recent research supports the hypothesis that enhancing let-7 expression in those cancers where it is downregulated may be a potential treatment option. Exosomes are tiny vesicles that move through body fluids and can include components like miRNAs (including let-7) that are important for communication between cells. Studies proved that exosomes are able to enhance tumor growth, angiogenesis, chemoresistance, metastasis, and immune evasion, thus suggesting their importance in GC management.

Characterizing the Inflammatory Microenvironment in K14-HPV16 Transgenic Mice: Mast Cell Infiltration and MicroRNA Expression

High-risk human papillomavirus (HPV) is the etiologic agent of several types of cancer. Mast cells’ role as either a driving or opposing force for cancer progression remains controversial. MicroRNAs are dysregulated in several HPV-induced cancers, and can influence mast cell biology. The aim of this study was to evaluate mast cell infiltration and to identify microRNAs potentially regulating this process. Transgenic male mice (K14-HPV16; HPV+) and matched wild-type mice (HPV−) received 7,12-Dimethylbenz[a]anthracene (DMBA) (or vehicle) over 17 weeks. Following euthanasia, chest skin and ear tissue samples were collected. Mast cell infiltration was evaluated by immunohistochemistry. MicroRNAs associated with mast cell infiltration were identified using bioinformatic tools. MicroRNA and mRNA relative expression was evaluated by RT-qPCR. Immunohistochemistry showed increased mast cell infiltration in HPV+ mice (p < 0.001). DMBA did not have any statistically significant influence on this distribution. Ear tissue of HPV+ mice showed increased mast cell infiltration (p < 0.01) when compared with chest skin samples. Additionally, reduced relative expression of miR-125b-5p (p = 0.008, 2−ΔΔCt = 2.09) and miR-223-3p (p = 0.013, 2−ΔΔCt = 4.42) seems to be associated with mast cell infiltration and increased expression of target gene Cxcl10. These results indicate that HPV16 may increase mast cell infiltration by down-regulating miR-223-3p and miR-125b-5p.

MicroRNA-Mediated Regulation of the Virus Cycle and Pathogenesis in the SARS-CoV-2 Disease

In the last few years, microRNA-mediated regulation has been shown to be important in viral infections. In fact, viral microRNAs can alter cell physiology and act on the immune system; moreover, cellular microRNAs can regulate the virus cycle, influencing positively or negatively viral replication. Accordingly, microRNAs can represent diagnostic and prognostic biomarkers of infectious processes and a promising approach for designing targeted therapies. In the past 18 months, the COVID-19 infection from SARS-CoV-2 has engaged many researchers in the search for diagnostic and prognostic markers and the development of therapies. Although some research suggests that the SARS-CoV-2 genome can produce microRNAs and that host microRNAs may be involved in the cellular response to the virus, to date, not enough evidence has been provided. In this paper, using a focused bioinformatic approach exploring the SARS-CoV-2 genome, we propose that SARS-CoV-2 is able to produce microRNAs sharing a strong sequence homology with the human ones and also that human microRNAs may target viral RNA regulating the virus life cycle inside human cells. Interestingly, all viral miRNA sequences and some human miRNA target sites are conserved in more recent SARS-CoV-2 variants of concern (VOCs). Even if experimental evidence will be needed, in silico analysis represents a valuable source of information useful to understand the sophisticated molecular mechanisms of disease and to sustain biomedical applications.

Polyphenols Could Prevent SARS-CoV-2 Infection by Modulating the Expression of miRNAs in the Host Cells

Coronaviruses (CoVs) are single-stranded RNA viruses which following virus attachment and entry into the host cell, particularly type 2 pneumocytes but also endothelial cells, release RNA into cytosol where it serves as a matrix for the host translation machinery to produce viral proteins. The viral RNA in cytoplasm can interact with host cell microRNAs which can degrade viral RNA and/or prevent viral replication. As such host cellular miRNAs represent key cellular mediators of antiviral defense. Polyphenols, plant food bioactives, exert antiviral properties, which is partially due to their capacity to modulate the expression of miRNAs. The objective of this work was to assess if polyphenols can play a role in prevention of SARS-CoV-2 associated complications by modulating the expression of host miRNAs. To test this hypothesis, we performed literature search to identify miRNAs that could bind SARS-CoV-2 RNA as well as miRNAs which expression can be modulated by polyphenols in lung, type 2 pneumocytes or endothelial cells. We identified over 600 miRNAs that have capacity to bind viral RNA and 125 miRNAs which expression can be modulated by polyphenols in the cells of interest. We identified that there are 17 miRNAs with both the capacity to bind viral RNA and which expression can be modulated by polyphenols. Some of these miRNAs have been identified as having antiviral properties or can target genes involved in regulation of processes of viral replication, apoptosis or viral infection. Taken together this analysis suggests that polyphenols could modulate expression of miRNAs in alveolar and endothelial cells and exert antiviral capacity.

Human MicroRNAs Interacting With SARS-CoV-2 RNA Sequences: Computational Analysis and Experimental Target Validation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel RNA virus affecting humans, causing a form of acute pulmonary respiratory disorder named COVID-19, declared a pandemic by the World Health Organization. MicroRNAs (miRNA) play an emerging and important role in the interplay between viruses and host cells. Although the impact of host miRNAs on SARS-CoV-2 infection has been predicted, experimental data are still missing. This study started by a bioinformatics prediction of cellular miRNAs potentially targeting viral RNAs; then, a number of criteria also based on experimental evidence and virus biology were applied, giving rise to eight promising binding miRNAs. Their interaction with viral sequences was experimentally validated by transfecting luciferase-based reporter plasmids carrying viral target sequences or their inverted sequences into the lung A549 cell line. Transfection of the reporter plasmids resulted in a reduction of luciferase activity for five out of the eight potential binding sites, suggesting responsiveness to endogenously expressed miRNAs. Co-transfection of the reporter plasmids along with miRNA mimics led to a further and strong reduction of luciferase activity, validating the interaction between miR-219a-2-3p, miR-30c-5p, miR-378d, miR-29a-3p, miR-15b-5p, and viral sequences. miR-15b was also able to repress plasmid-driven Spike expression. Intriguingly, the viral target sequences are fully conserved in more recent variants such as United Kingdom variant B.1.1.7 and South Africa 501Y.V2. Overall, this study provides a first experimental evidence of the interaction between specific cellular miRNAs and SARS-CoV-2 sequences, thus contributing to understanding the molecular mechanisms underlying virus infection and pathogenesis to envisage innovative therapeutic interventions and diagnostic tools.

Epstein-Barr virus, human papillomavirus and herpes simplex virus 2 co-presence severely dysregulates miRNA expression

This cross-sectional study evaluated the expression of miR-let-7b, miR-21, miR-125b, miR-143, miR-145, miR-155, miR-182, miR-200c, p53 gene, Ki67, SCCA1 and CD4+ T-cell counts among 319 women, to Epstein-Barr virus, human papillomavirus and herpes simplex virus 2 mono-infections and co-infections, using enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction methods. This study suggests that malignancies associated with viral co-infection could be diagnosed early by monitoring cluster of differentiation 4+ T-cell counts and serum expression of miR-145 and miR-182.

MicroRNA-101-3p, MicroRNA-195-5p, and MicroRNA-223-3p in Peripheral Blood Mononuclear Cells May Serve as Novel Biomarkers for Syphilis Diagnosis

OBJECTIVES

Syphilis is a sexually transmitted disease of global prevalence. Current diagnostic methods lack sensitivity and specificity, which limits the early diagnosis and prognosis of the disease. MiRNAs hold great promise as potential biomarkers for infectious diseases diagnosis. We previously profiled the expression of miRNAs in PBMCs from patients with different stages of syphilis. We aimed to further confirm the miR-101-3p, miR-195-5p, and miR-223-3p expression profiles and evaluate their diagnostic value in syphilis infection.

METHODS

The expression levels of PBMC-derived miR-101-3p, miR-195-5p, and miR-223-3p were analyzed in 133 syphilis patients, 18 non-syphilis patients, and 23 healthy controls by RT-qPCR. ROC analysis was used to evaluate the differentiation power of these miRNAs in syphilis diagnosis, while the correlation between the expression of these miRNAs and TRUST titer was also statistically analyzed.

RESULTS

These miRNAs were significantly upregulated in syphilis patients in a stage-specific manner. ROC analysis indicated that miR-223-3p was powerful in discriminating between controls and patients with early, primary, secondary, and latent syphilis, as well as serological cure; the miR-195-5p/miR-223-3p panel showed an improved capacity to differentiate between syphilis patients, primary, or serofast-stage syphilis and controls, while the three miRNAs combined showed an improved capacity to differentiate latent syphilis or serological cure from controls. Importantly, miR-101-3p and miR-223-3p singly or jointly could specifically distinguish syphilis from non-syphilis patients. Moreover, TRUST titer was significantly correlated with miR-101-3p expression.

CONCLUSIONS

MiR-101-3p, miR-195-5p, and miR-223-3p might singly or jointly be potential diagnostic biomarkers at different stages of syphilis.

A Novel Circulating MiRNA-Based Signature for the Diagnosis and Prognosis Prediction of Early-Stage Cervical Cancer

Background:

MicroRNAs (miRNAs) have been shown to play a key role in regulating the progression of cervical cancer (CC). This study aimed to develop a circulating miRNA-based molecular signature for the diagnosis and prognosis prediction of early-stage CC.

Methods:

This study included 112 patients diagnosed with early-stage CC, 45 patients confirmed with cervical intraepithelial neoplasia (CIN) and 90 healthy subjects. Compared to the normal controls, the expression level of miR-21 was increased, while the levels of miR-125b and miR-370 were decreased in CC in both GSE30656 and The Cancer Genome Atlas (TCGA) cohort. The expression levels and diagnostic value of these candidate miRNAs were then validated through qRT-PCR. Their diagnostic and prognostic values for early-stage CC were further explored.

Results:

Compared to the patients with CIN and healthy subjects, serum miR-21 was increased, while serum miR-125b and serum miR-370 were reduced in early-stage CC. In addition, combining these molecules yielded good performance for differentiating early-stage CC from CIN or healthy subjects. Moreover, strong association was found between serum miR-21 and lymph node metastasis (LNM) as well as recurrence-free survival of early-stage CC. Similar observations were found for serum miR-125b and serum miR-370. Patients with simultaneously high serum miR-21 + low serum miR-125b + low serum miR-370 suffered a high risk of LNM and recurrence, while those with low serum miR-21 + high serum miR-125b + high serum miR-370 had little risk for LNM and recurrence.

Conclusions:

Combining serum miR-21, miR-125b and miR-370 as a miRNA-based signature is promising for the detection and prognosis prediction of early-stage CC.

The Role of Ataxia Telangiectasia Mutant and Rad3-Related DNA Damage Response in Pathogenesis of Human Papillomavirus

Human papillomavirus (HPV) infection leads to a variety of benign lesions and malignant tumors such as cervical cancer and head and neck squamous cell carcinoma. Several HPV vaccines have been developed that can help to prevent cervical carcinoma, but these vaccines are only effective in individuals with no prior HPV infection. Thus, it is still important to understand the HPV life cycle and in particular the association of HPV with human pathogenesis. HPV production requires activation of the DNA damage response (DDR), which is a complex signaling network composed of multiple sensors, mediators, transducers, and effectors that safeguard cellular DNAs to maintain the host genome integrity. In this review, we focus on the roles of the ataxia telangiectasia mutant and Rad3-related (ATR) DNA damage response in HPV DNA replication. HPV can induce ATR expression and activate the ATR pathway. Inhibition of the ATR pathway results in suppression of HPV genome maintenance and amplification. The mechanisms underlying this could be through various molecular pathways such as checkpoint signaling and transcriptional regulation. In light of these findings, other downstream mechanisms of the ATR pathway need to be further investigated for better understanding HPV pathogenesis and developing novel ATR DDR-related inhibitors against HPV infection.

Transcription factors in SOX family: Potent regulators for cancer initiation and development in the human body

Transcription factors (TFs) have a key role in controlling the gene regulatory network that sustains explicit cell states in humans. However, an uncontrolled regulation of these genes potentially results in a wide range of diseases, including cancer. Genes of the SOX family are indeed crucial as deregulation of SOX family TFs can potentially lead to changes in cell fate as well as irregular cell growth. SOX TFs are a conserved group of transcriptional regulators that mediate DNA binding through a highly conserved high-mobility group (HMG) domain. Accumulating evidence demonstrates that cell fate and differentiation in major developmental processes are controlled by SOX TFs. Besides; numerous reports indicate that both up- and down-regulation of SOX TFs may induce cancer progression. In this review, we discuss the involvement of key TFs of SOX family in human cancers.

Comparable expression of miR-let-7b, miR-21, miR-182, miR-145, and p53 in serum and cervical cells: Diagnostic implications for early detection of cervical lesions

OBJECTIVE

The high mortality associated with cervical cancer is due to low uptake of Pap smear test, lack of early diagnostic biomarkers and less-invasive approach, and late presentation of the disease. This study evaluated the expression of hsa-miR-let-7b, hsa-miR-21, hsa-miR-125b, hsa-miR-143, hsa-miR-145, hsa-miR-146a, hsa-miR-155, hsa-miR-182, hsa-miR-200c, and p53 in serum and cervix in relation to classes of Pap smear, in a bid to identify a serum panel for early diagnosis of cervical lesions.

METHODOLOGY

This study included 329 women; 159 healthy women (HW), 46 cervicitis, 46 atypical squamous cells of undetermined significance (ASCUS), 40 low-grade squamous cell intraepithelial lesion (LSIL), 28 high-grade squamous cell intraepithelial lesion (HSIL), and 10 squamous cell carcinoma (SCC). Expression of microRNAs (miRNAs) and p53 was assessed using reverse transcriptase polymerase chain reaction.

RESULTS

Except for miR-143 and miR-146a, significant correlations were observed between serum and cervix expression of miRNAs and p53 in relation to levels and classes of Pap smear (P < 0.05). Relatively, higher expression of miR-21, miR-146a, miR-155, miR-182, and miR-200c and lower expression of let-7b and miR-145 were observed in sera associated with cervical abnormalities than in sera associated with normal cervix (P < 0.0001, P = 0.001, P < 0.0001, P = 0.003, P = 0.007, P = 0.036, and P = 0.046, respectively). Higher and lower expression of p53 was observed in women diagnosed of LSIL and SCC, respectively, than in HW (P < 0.0001).

CONCLUSION

This study suggests that serum expression of miR-21, miR-182, let-7b, miR-145, and p53 is comparable to cervical cell expression and could be useful in differentiating abnormal cervix from the healthy cervix.

Interaction of miR-125b-5p with Human antigen R mRNA: Mechanism of controlling HCV replication

Cellular miRNAs influence Hepatitis C virus (HCV) infection in multiple ways. In this study, we demonstrate that miR-125b-5p is upregulated in HCV infected patient serum samples as well as in HCV infected liver carcinoma cells and is involved in translational regulation of one of its predicted targets, Human antigen R (HuR). We used miRNA mimics and antagomiRs to confirm that HuR is a bonafide miR-125b target. Previously, we have shown that HuR is a positive regulator of HCV replication, whereas we noticed that miR-125b is a negative regulator of HCV infection. As a connecting link between these two observations, we showed that knockdown of miR-125b-5p increased HuR protein levels and rescued HCV replication when the availability of HuR in the cytoplasm was compromised using siRNAs against HuR or an inhibitor of HuR export to the cytoplasm. Overall, the study sheds light on the ability of host cell to use a miRNA as a tool to control virus propagation.

Loss of miR-143 and miR-145 in condyloma acuminatum promotes cellular proliferation and inhibits apoptosis by targeting NRAS

The expression profile of miRNAs and their function in condyloma acuminatum (CA) remains unknown. In this study, we aimed to detect the effects of miR-143 and miR-145, the most downregulated in CA samples using high-throughput sequencing, on cell proliferation and apoptosis, to determine a novel therapeutic target for CA recurrence. RT-qPCR was used to validate the lower expression of miR-143 and miR-145 in a larger size of CA samples, and the expression of NRAS in CA samples was significantly higher than self-controls as determined by western blotting assay. Luciferase assay was performed to confirm that miR-143 or miR-145 targeted NRAS directly. Transduction of LV-pre-miR-143 or LV-pre-miR-145 to human papilloma virus (HPV)-infected SiHa cells led to reduced proliferation, greater apoptosis and inhibition of expression of NRAS, PI3 K p110α and p-AKT. However, knockout of miR-143 or miR-145 in human epidermal keratinocytes by delivery of CRISPR/CAS9-gRNA for target miRNAs protected cells from apoptosis and upregulated expression of target genes as described above. MiR-143 and miR-145 sensitized cells to nutlin-3a, a p53 activator and MDM2 antagonist, while their loss protected cells from the stress of nutlin-3a. Furthermore, siRNA targeting NRAS showed similar effects on proliferation and apoptosis as miR-143 or miR-145. Taken together, our results suggest that loss of miR-143 or miR-145 in CA protects HPV-infected cells from apoptosis induced by environmental stress, in addition to promoting cellular proliferation and inhibiting apoptosis by targeting NRAS/PI3 K/ATK. Restoration of miR-143 or miR-145 might provide an applicable and novel approach to block the recurrence and progression of CA.

DNA methylation regulated microRNAs in HPV-16-induced head and neck squamous cell carcinoma (HNSCC)

INTRODUCTION

Epigenetic modifications have been reported to play an important role in regulating gene expression and these modifications become critical when they have a role in controlling another important layer of epigenetic regulation namely microRNAs. In the present study, we have identified the microRNAs that may be regulated by promoter DNA methylation and histone acetylation in Human papilloma virus-positive head and neck squamous cell carcinoma.

METHODOLOGY

HPV-negative cell line (UPCI:SCC-116) and HPV-16 +ve cell line (UPCI:SCC-090) were treated with methylation inhibitor (5-aza-2'-deoxycytidine, AZA) and acetylation inhibitor (Trichostatin-A, TSA), followed by micro-array analysis. The differentially expressed miRNAs were validated in control (n = 10), HPV-16 +ve (n = 30), and HPV -ve (n = 30) HNC, TCGA (n = 529) tissue samples, and two HPV -ve (SCC116 and Hacat) and two HPV +ve (SCC090 and SiHa) cell lines. Methylation-specific PCR (MSP) and chromatin immunoprecipitation assay (CHIP) were performed to validate their regulation. In silico and in vitro analyses of identified miRNAs were done to study putative pathways they target and their possible role in carcinogenesis.

RESULTS

Among 10 miRNAs specifically up-regulated in microarray analysis of AZA-treated SCC090 cells, we observed significantly decreased expression of hsa-miR-181c-5p, hsa-miR-132-5p, hsa-miR-658 in HPV +ve HNC cohort, TCGA tissue samples, and cell lines as compared to their HPV -ve counterpart, and their promoter region also possesses CpG islands. MSP and analysis of TCGA data (MethHC) revealed increased frequency of methylation at the promoter of hsa-miR-132-5p that is negatively correlated with its expression. In TSA-treated SCC090 cells, out of 7 miRNAs, two namely Hsa-miR-129-2-3p and Hsa-miR-449a were found to be up-regulated as compared to HPV -ve cells. However, the levels of enrichment by anti-acetyl-H3 and anti-acetyl-H4 were significantly low in cell lines compared to respective controls and both were up-regulated in HPV +ve compared to HPV -ve TCGA tissue samples. In silico analysis revealed hsa-miR-132-5p targeted canonical β-catenin/wnt pathway and modulation of down-stream genes of the pathway was observed on over-expression/inhibition of hsa-miR-132-5p.

CONCLUSION

This study suggests the role of epigenetic modifications in regulating expression of miRNAs in HPV +ve HNSCC.

Role of non-coding RNAs in head and neck squamous cell carcinoma: A narrative review

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide with high recurrence, metastasis, and poor treatment outcome. Recent studies have reported that non-coding RNA (ncRNA) might play critical role in regulating different types of cancer. MicroRNAs (miRs) are short ncRNAs (20-25 nucleotides) responsible for post-transcriptional regulation of gene expression and may have a role in oncogenesis by acting as oncomiRs or tumor suppressor miRs. Long non-coding RNAs (lncRNAs) are heterogenous group of ncRNAs more than 200 nucleotides long, can act in cis and/or in trans, and have been also implicated in carcinogenesis. These molecules have been suggested to be promising candidates as diagnostic and prognostic biomarkers and for development of novel therapeutic approaches. In this review, we have summarized recent findings on role of these ncRNAs in HPV-negative (HPV-ve) and HPV-positive (HPV+ve) HNSCC. The available literature supports differential expression of both microRNAs and long non-coding RNAs, which include oncogenic ncRNAs (miR-21, miR-31, miR-155, miR-211, HOTAIR, and MALAT1) and tumor suppressor ncRNAs (let7d, miR-17, miR-375, miR-139, and MEG3) in HPV+ve HNSCC tumors as compared to HPV-ve tumors and they have distinct role in the pathophysiology of these two types of HNSCCs.

DNA damage response is hijacked by human papillomaviruses to complete their life cycle

The DNA damage response (DDR) is activated when DNA is altered by intrinsic or extrinsic agents. This pathway is a complex signaling network and plays important roles in genome stability, tumor transformation, and cell cycle regulation. Human papillomaviruses (HPVs) are the main etiological agents of cervical cancer. Cervical cancer ranks as the fourth most common cancer among women and the second most frequent cause of cancer-related death worldwide. Over 200 types of HPVs have been identified and about one third of these infect the genital tract. The HPV life cycle is associated with epithelial differentiation. Recent studies have shown that HPVs deregulate the DDR to achieve a productive life cycle. In this review, I summarize current findings about how HPVs mediate the ataxia-telangiectasia mutated kinase (ATM) and the ATM-and RAD3-related kinase (ATR) DDRs, and focus on the roles that ATM and ATR signalings play in HPV viral replication. In addition, I demonstrate that the signal transducer and activator of transcription-5 (STAT)-5, an important immune regulator, can promote ATM and ATR activations through different mechanisms. These findings may provide novel opportunities for development of new therapeutic targets for HPV-related cancers.

Plasma MicroRNA Levels Are Associated With Hepatitis B e Antigen Status and Treatment Response in Chronic Hepatitis B Patients

Background

Hepatitis B virus (HBV) modulates microRNA (miRNA) expression to support viral replication. The aim of this study was to identify miRNAs associated with hepatitis B e antigen (HBeAg) status and response to antiviral therapy in patients with chronic hepatitis B (CHB) , and to assess if these miRNAs are actively secreted by hepatoma cells.

Methods

Plasma miRNA levels were measured by reverse-transcription quantitative polymerase chain reaction in healthy controls (n = 10) and pretreatment samples of an identification cohort (n = 24) and a confirmation cohort (n = 64) of CHB patients treated with peginterferon/nucleotide analogue combination therapy. Levels of HBV-associated miRNAs were measured in cells, extracellular vesicles, and hepatitis B surface antigen (HBsAg) particles of hepatoma cell lines.

Results

HBeAg-positive patients had higher plasma levels of miR-122-5p, miR-125b-5p, miR-192-5p, miR-193b-3p, and miR-194-5p compared to HBeAg-negative patients, and levels of these miRNAs were associated with HBV DNA and HBsAg levels. Pretreatment plasma levels of miR-301a-3p and miR-145-5p were higher in responders (combined response or HBsAg loss) compared to nonresponders. miR-192-5p, miR-193b-3p, and miR-194-5p were present in extracellular vesicles and HBsAg particles derived from hepatoma cells.

Conclusions

We identified miRNAs that are associated with HBeAg status, levels of HBV DNA and HBsAg, and treatment response in CHB patients. We demonstrated that several of these miRNAs are present in extracellular vesicles and HBsAg particles secreted by hepatoma cells.

Differential expression of plasma microRNA-125b in hepatitis B virus-related liver diseases and diagnostic potential for hepatitis B virus-induced hepatocellular carcinoma

AIM

Acting as a tumor suppressor, microRNA (miR)-125b shows aberrant low expression in hepatocellular carcinoma (HCC), and researchers have found that its dysregulation has a close relationship with hepatitis B virus (HBV) infection. Here, we investigated the expression profile of this miRNA in the plasma of healthy subjects and patients with chronic HBV-related liver diseases in order to confirm the feasibility of this circulating miRNA as a differential diagnostic biomarker for HBV-induced HCC (HBV-HCC).

METHODS

A total of 242 individuals were enrolled in this study. The expression levels of plasma miR-125b were examined using quantitative real-time polymerase chain reaction technology.

RESULTS

The levels of plasma miR-125b were remarkably decreased in HBV-HCC patients compared to healthy controls and HBV subjects without HCC (all P < 0.001), and the low plasma miR-125b levels in HBV-HCC patients were associated with higher prevalence of metastasis (P = 0.021). The receiver-operating characteristic curve analyses indicated that plasma miR-125b presented a high accuracy (area under the curve = 0.891, 0.958, 0.958) for diagnosing HBV-HCC cases from healthy controls and patients with chronic hepatitis B and HBV-related liver cirrhosis, respectively. In addition, our study found that the expression levels of plasma miR-125b in HBV patients without HCC were higher than those in healthy subjects (P < 0.001); it yielded an area under the curve of 0.691 in discriminating patients with chronic HBV infection who were negative for HCC from healthy controls.

CONCLUSION

The measurement of plasma-based miR-125b holds promise as a diagnostic marker for HBV-HCC differential diagnosis and for chronic HBV viral infection. Those HBV-infected individuals with increased risk of HCC would be detected early through monitoring the changes in this circulating miRNA.

Comparison of the miRNA profiles in HPV-positive and HPV-negative tonsillar tumors and a model system of human keratinocyte clones

BACKGROUND

Better insights into the molecular changes involved in virus-associated and -independent head and neck cancer may advance our knowledge of HNC carcinogenesis and identify critical disease biomarkers. Here we aimed to characterize the expression profiles in a matched set of well-characterized HPV-dependent and HPV-independent tonsillar tumors and equivalent immortalized keratinocyte clones to define potential and clinically relevant biomarkers of HNC of different etiology.

METHODS

Fresh frozen tonsillar cancer tissues were analyzed together with non-malignant tonsillar tissues and compared with cervical tumors and normal cervical tissues. Furthermore, relative miRNAs abundance levels of primary and immortalized human keratinocyte clones were evaluated. The global quantitation of miRNA gene abundance was performed using a TaqMan Low Density Array system. The confirmation of differentially expressed miRNAs was performed on a set of formalin-fixed paraffin-embedded tumor samples enriched for the tumor cell fraction by macrodissection.

RESULTS

We defined 46 upregulated and 31 downregulated miRNAs characteristic for the HPV-positive tonsillar tumors and 42 upregulated miRNAs and 42 downregulated miRNAs characteristic for HPV-independent tumors. In comparison with the expression profiles in cervical tumors, we defined miR-141-3p, miR-15b-5p, miR-200a-3p, miR-302c-3p, and miR-9-5p as specific for HPV induced malignancies. MiR-335-5p, miR-579-3p, and miR-126-5p were shared by the expression profiles of HPV-positive tonsillar tumors and of the HPV immortalized keratinocyte clones, whereas miR-328-3p, miR-34c-3p, and miR-885-5p were shared by the miRNA profiles of HPV-negative tonsillar tumors and the HPV-negative keratinocytes.

CONCLUSIONS

We identified the miRNAs characteristic for HPV-induced tumors and tonsillar tumors of different etiology, and the results were compared with those of the model system. Our report presents the basis for further investigations leading to the identification of clinically relevant diagnostic and/or therapeutic biomarkers for tumors of viral and non-viral etiology.

MicroRNA-125a-5p modulates human cervical carcinoma proliferation and migration by targeting ABL2

Background

In this study, we intended to understand the regulatory mechanisms of microRNA-125a-5p (miR-125a-5p) in human cervical carcinoma.

Methods

The gene expressions of miR-125a-5p in seven cervical carcinoma cell lines and 12 human cervical carcinoma samples were evaluated by quantitative real-time reverse transcription polymerase chain reaction. Ca-Ski and HeLa cells were transduced with lentivirus carrying miR-125a-5p mimics, and the effects of lentivirus-induced miR-125a-5p upregulation on cervical carcinoma proliferation and migration were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and transwell assays, respectively. In additional, HeLa cells were inoculated into null mice to evaluate the effect of miR-125a-5p upregulation on in vivo cervical carcinoma growth. The direct regulation of miR-125a-5p on its target gene, ABL proto-oncogene 2 (ABL2), in cervical carcinoma was evaluated by quantitative real-time reverse transcription polymerase chain reaction, Western blotting and luciferase reporter assays, respectively. ABL2 was then downregulated by small interfering RNA to examine its effect on cervical carcinoma proliferation and migration.

Results

miR-125a-5p was downregulated in both cervical carcinoma cell lines and human cervical carcinomas. In Ca-Ski and HeLa cells, lentivirus-mediated miR-125a-5p upregulation inhibited cancer proliferation and migration in vitro and cervical carcinoma transplantation in vivo. ABL2 was shown to be directly targeted by miR-125a-5p. In cervical carcinoma, ABL2 gene and protein levels were both downregulated by miR-125a-5p. Small interfering RNA-mediated ABL2 downregulation also had tumor-suppressive effects on cervical carcinoma proliferation and migration.

Conclusion

The molecular pathway of miR-125a-5p/ABL2 plays an important role in human cervical carcinoma. Targeting miR-125a-5p/ABL2 pathway may provide a new treatment strategy for patients with cervical carcinoma.

HPV-16 E6 promotes cell growth of esophageal cancer via downregulation of miR-125b and activation of Wnt/β-catenin signaling pathway

High-risk human papillomavirus (HPV) is a possible cause of esophageal cancer. However, the molecular pathogenesis of HPV-infected esophageal cancer remains unclear. The expression levels of some microRNAs including miR-125b have been negatively correlated with HPV infection, and miR-125b downregulation is associated with tumorigenesis. In addition, Wnt/β-catenin signaling pathway has been suggested to play an important role in esophageal cancer (EC). We examined miR-125b and Wnt/β-catenin signaling pathway in HPV-16 E6 promoted tumor progression in EC. HPV-16 E6 transfection decreased markedly the expression levels of miR-125b and promoted the colony formation in the Eca 109 and Kyse 150 cell lines, and restoration of miR-125b expression level antagonized the increased colony formation in HPV-16 E6 transfected cell lines. We also demonstrated that overexpression of E6 upregulated the Wnt/β-catenin signaling activity via modulating the multiple regulators including TLE1, GSK3β, and sFRP4. Overexpression of miR-125b restored the expression levels of these proteins. Expression of miR-125b was lower in HPV-16 E6 positive esophageal cancer tissues, and was negatively correlated with E6 mRNA levels. Our results indicate that HPV-16 E6 promotes tumorigenesis in EC via down-regulation of miR-125b, and this underlying mechanism may be involved in the activation of the Wnt/β-catenin signaling pathway.

Role of miRNA in cancer diagnosis, prognosis, therapy and regulation of its expression by Epstein-Barr virus and human papillomaviruses: With special reference to oral cancer

MicroRNAs (miRNAs) belong to class of small non-coding RNAs that regulate numerous biological processes by targeting broad set of messenger RNAs. Research on miRNA-based biomarkers has witnessed phenomenal growth, owing to non-invasive nature of miRNA based screening assays and their sensitivity and specificity in detecting cancers. Their discovery in humans in 2000 has led to an explosion in research in terms of their role as biomarker, therapeutic target and trying to elucidate their function. This review aims to summarize the function of microRNAs as well as to examine how dysregulation at any step in their biogenesis or functional pathway can play a role in development of cancer, together with its possible involvement in oral cancer. Overexpression of oncogenic miRNA may reduce protein products of tumor-suppressor genes but loss of tumor-suppressor miRNA expression may cause elevated levels of oncogenic protein. One or both of these alterations could represent new targets for cancer diagnosis and treatment in future. Many researchers have focused on genetic and epigenetic alterations in OSCC cells. The genetic susceptibility, endemic environment factors, and Epstein-Barr virus (EBV) infection are believed to be the major etiologic factors of OSCC. Once metastasis occurs, prognosis is very poor. It is urgently needed to develop biomarkers for early clinical diagnosis/prognosis, and novel effective therapies for oral carcinoma. High-risk HPV infection leads to aberrant expression of cellular oncogenic and tumor suppressive miRNAs. The emergence of miRNA knowledge, and its potential interactive action with such alterations, therefore creates new understanding of cell transformation.

miR-34a and miR-125b Expression in HPV Infection and Cervical Cancer Development

We aimed to characterize miR-125b and miR-34a expression in 114 women with different cervical lesions: normal epithelium with (n = 20) and without (n = 29) HPV infection; LSIL (n = 28); HSIL (n = 29); and ICC (n = 8). miRNA expression analysis was performed by comparing the distinct groups with the reference group (women with normal epithelium without HPV). For miR-125b, we observed a twofold (2^−ΔΔCt = 2.11; P = 0.038) increased expression among women with normal epithelium with HPV infection and a trend of downregulation in different cervical lesions including an 80% reduction (2^−ΔΔCt = 0.21; P = 0.004) in ICC. Similarly, miR-34a expression analysis revealed an increased expression (2^−ΔΔCt = 1.69; P = 0.049) among women with normal cervix and HPV infection, and despite no significant correlation with cervical lesions, its expression was increased by twofold (2^−ΔΔCt = 2.08; P = 0.042) in ICC. Moreover, miR-125b levels were able to predict invasive cancers with 88% sensitivity and 69% specificity. Results showed that while miR-34a expression seems to be correlated with invasive cervical cancer, miR-125b expression is significantly changed within the different cervical lesions and their levels should be further investigated as possible predictive/prognostic biomarkers using a noninvasive approach.

Two less common human microRNAs miR-875 and miR-3144 target a conserved site of E6 oncogene in most high-risk human papillomavirus subtypes

Human papillomaviruses (HPVs) including high-risk (HR) and low-risk (LR) subtypes have distinguishable variation on both genotypes and phenotypes. The co-infection of multiple HR-HPVs, headed by HPV16, is common in cervical cancer in female. Recently accumulating reports have focused on the interaction between virus and host, particularly the role of human microRNAs (miRNAs) in anti-viral defense by targeting viral genome. Here, we found a well-conserved target site of miRNAs in the genomes of most HR-HPVs, not LR-HPVs, by scanning all potential target sites of human miRNAs on 24 HPVs of unambiguous subtypes of risk. The site is targeted by two less common human miRNAs, miR-875 and miR-3144, and is located in E6 oncogene open reading frame (ORF) and overlap with the first alternative splice exon of viral early transcripts. In validation tests, miR-875 and miR-3144 were identified to suppress the target reporter activity markedly and inhibit the expression of both synthetically exogenous E6 and endogenous E6 oncogene. High level of two miRNAs can inhibit cell growth and promote apoptosis in HPV16-positive cervical cancer cells. This study provides a promising common target of miRNAs for most HR-HPVs and highlights the effects of two low expressed human miRNAs on tumour suppression.

Fluctuating expression of microRNAs in adenovirus infected cells

The changes in cellular microRNA (miRNA) expression during the course of an adenovirus type 2 infection in human lung fibroblast were studied by deep RNA sequencing. Expressions of 175 miRNAs with over 100 transcripts per million nucleotides were changed more than 1.5-fold. The expression patterns of these miRNAs changed dramatically during the course of the infection, from upregulation of the miRNAs known as tumor suppressors (such as miR-22, miR-320, let-7, miR-181b, and miR-155) and down-regulation of oncogenic miRNAs (such as miR-21 and miR-31) early to downregulation of tumor suppressor miRNAs (such as let-7 family, mir-30 family, 23/27 cluster) and upregulation of oncogenic miRNAs (include miR-125, miR-27, miR-191) late after infection. The switch in miRNA expression pattern occurred when adenovirus DNA replication started. Furthermore, deregulation of cellular miRNA expression was a step-wise and special sets of miRNAs were deregulated in different phases of infection.

MicroRNAs in virus-induced tumorigenesis and IFN system

Numerous microRNAs (miRNAs), small non-coding RNAs encoded in the human genome, have been shown to be involved in cancer pathogenesis and progression. There is evidence that some of these miRNAs possess proapoptotic or proliferation promoting roles in the cell by negatively regulating target mRNAs. Oncogenic viruses are able to produce persistent infection, favoring tumor development by deregulating cell proliferation and inhibiting apoptosis. It has been recently suggested that cellular miRNAs may participate in host-virus interactions, influencing viral replication. Many mammalian viruses counteract this cellular antiviral defense by using viral proteins but also by encoding viral miRNAs involved in virus-induced tumorigenesis. Interferons (IFNs) modulate a number of non-coding RNA genes, especially miRNAs, that may be used by mammalian organisms as a mechanism of IFN system to combat viral infection and related diseases. In particular, IFNs might induce specific cellular miRNAs that target viral transcripts thereby using this strategy as part of their effectiveness against invading viruses. Therefore IFNs, interferon stimulated genes and miRNAs could act synergistically as innate response to virus infection to induce a potent non-permissive cellular environment for virus replication and virus-induced cancer. The relevance of this reviewed research topic is clearly related to the observation that although virus infections are responsible of specific tumors, other unidentified genetic alterations are likely involved in the induction of malignant transformation. The identification of such genetic alterations, i.e. miRNA expression in transformed cells, would be of considerable importance for the analysis of the pathogenesis and for the treatment of cancer induced by specific viruses as well as for the advancement of the current knowledge on the molecular mechanisms underlying virus-host interaction. In this respect, we will review also the important, still little explored, roles of miRNAs acting both as IFN-stimulated anti-viral molecules and as critical regulators of IFNs and IFN-stimulated genes.

Multistep model of cervical cancer: participation of miRNAs and coding genes

Aberrant miRNA expression is well recognized as an important step in the development of cancer. Close to 70 microRNAs (miRNAs) have been implicated in cervical cancer up to now, nevertheless it is unknown if aberrant miRNA expression causes the onset of cervical cancer. One of the best ways to address this issue is through a multistep model of carcinogenesis. In the progression of cervical cancer there are three well-established steps to reach cancer that we used in the model proposed here. The first step of the model comprises the gene changes that occur in normal cells to be transformed into immortal cells (CIN 1), the second comprises immortal cell changes to tumorigenic cells (CIN 2), the third step includes cell changes to increase tumorigenic capacity (CIN 3), and the final step covers tumorigenic changes to carcinogenic cells. Altered miRNAs and their target genes are located in each one of the four steps of the multistep model of carcinogenesis. miRNA expression has shown discrepancies in different works; therefore, in this model we include miRNAs recording similar results in at least two studies. The present model is a useful insight into studying potential prognostic, diagnostic, and therapeutic miRNAs.

miR-125b inhibits hepatitis B virus expression in vitro through targeting of the SCNN1A gene

microRNAs (miRNAs) are small noncoding RNAs that modulate gene expression at the posttranscriptional level, playing an important role in many diseases. However, reports concerning the role of miRNA in hepatitis B virus (HBV) infection are limited. miRNA chips were used to investigate miRNA changes during HBV infection in vitro. Bioinformatics analysis was used to explore possible miRNA and target genes during HBV infection. The expression of miR-125b and its potential target gene, sodium channel, non-voltage-gated 1 alpha (SCNN1A), was further analyzed. A total of 136 miRNAs were analyzed in an HBV transient transfection model (HepG2-HBV1.3), and 78 miRNAs were differentially expressed in HepG2.2.15 cells compared with HepG2 cells. miR-125b expression was decreased in both HepG2-HBV1.3 and HepG2.2.15 cells, and ectopic expression of miR-125b inhibited HBV DNA intermediates and secretion of HBsAg and HBeAg. miR-125b also inhibited the mRNA and protein levels of SCNN1A. Using a dual luciferase reporter system, we found that SCNN1A was one of the targets of miR-125b. In this study, we found that miR-125b inhibits HBV expression in vitro by regulating SCNN1A expression.

miR-375 activates p21 and suppresses telomerase activity by coordinately regulating HPV E6/E7, E6AP, CIP2A, and 14-3-3ζ

Background

While microRNAs (miRNAs) are extensively studied in post-transcriptional regulation of gene expressions in many biological processes, cellular miRNA-mediated regulation of viral genes remains unclear. In particular, the interplay between human papillomavirus (HPV) genes and miRNAs and how these interactions contribute to HPV-associated cancers remain elusive.

Methods

Transient transfection of miR-375-mimic was used to compensate the loss-of-function of miR-375 in HPV-positive cancer. Regulation of oncogenic molecules and their downstream molecules via miR-375 in HPV-positive cancer was investigated using qRT-PCR, western blot, dual luciferase assay, indirect immunofluorescence analysis. All experiments were conducted at least three times to achieve statistical significance determined by Student t-test.

Results

In this study, we demonstrated how miR-375 negatively regulates HPV16 and 18 transcripts. We also found a cellular protein, E6-associated protein (E6AP), directly regulated by miR-375. miR-375-mediated repression of HPV transcripts and E6AP elevated major tumor suppressors p53, p21, and retinoblastoma protein 1 (RB). Cooperative regulation of miR-375 targets along with the increase of tumor suppressors led to ~60% reduction of telomerase reverse transcriptase (TERT) transcription followed by ~35% decrease of telomerase activity. Furthermore, miR-375-mediated regulation of 14-3-3ζ contributes to decrease telomerase activity by altering nuclear translocation of TERT.

Conclusion

Taken together, miR-375-mediated suppression of multiple oncogenic components in HPV-associated carcinogenesis generates a cumulative biological response to rescue key tumor suppressors and diminish telomerase activity, which results in cell cycle arrest and cell proliferation inhibition.

MicroRNAs as biomarkers of cervical cancer development: a literature review on miR-125b and miR-34a

MicroRNAs are non-coding RNAs with important functions in several biological processes, such as, regulation of cell cycle, immune response, inflammation, and apoptosis. In fact, deregulation and abnormal expression of these molecules is associated with human pathologies including cancer and several have already emerged as potential prognostic biomarkers in different neoplasias. miR-34a is directly regulated by p53 and acts as tumor suppressor while miR-125b plays a significant role in immune response and apoptosis. In cervical carcinogenesis, HPV proteins seem to interact with both miR-34a and miR-125b changing its expression and promoting persistent infection and cervical cancer development. In this review we describe the potential role of miR-125b and miR-34a in cervical carcinogenesis, including interaction with HPV and mechanism of deregulation. Additionally, their clinical applications in cervical cancer as prognostic/predictive biomarkers are also briefly discussed.

Multispectral Imaging

The field of anatomic pathology has changed significantly over the last decades and, as a result of the technological developments in molecular pathology and genetics, has had increasing pressures put on it to become quantitative and to provide more information about protein expression on a cellular level in tissue sections. Multispectral imaging (MSI) has a long history as an advanced imaging modality and has been used for over a decade now in pathology to improve quantitative accuracy, enable the analysis of multicolor immunohistochemistry, and drastically reduce the impact of contrast-robbing tissue autofluorescence common in formalin-fixed, paraffin-embedded tissues. When combined with advanced software for the automated segmentation of different tissue morphologies (eg, tumor vs stroma) and cellular and subcellular segmentation, MSI can enable the per-cell quantitation of many markers simultaneously. This article covers the role that MSI has played in anatomic pathology in the analysis of formalin-fixed, paraffin-embedded tissue sections, discusses the technological aspects of why MSI has been adopted, and provides a review of the literature of the application of MSI in anatomic pathology.

microRNA portraits in human vulvar carcinoma

Unregulated expression of microRNAs is well known and has already been demonstrated in many tumor types. However, in vulvar carcinoma this field has been unknown territory. Our study characterizes microRNA in vulvar tumors through an expression profile of 754 miRNAs, relating this with clinical and anatomopathologic data, and presence of HPV infection. Twenty HPV-negative and 20 HPV-positive samples, genotyped for high-risk HPVs (HPV16, 18, 31, 33) and a pool of seven normal vulvar skin samples were used for the identification of differentially expressed miRNAs by TLDA Quantitative Real Time PCR (qRT-PCR). Twenty-five differentially expressed microRNAs between HPV-positive and HPV-negative groups and 79 differentially expressed on the tumor compared with normal samples were obtained. A network between microRNA expression profiles and putative target mRNAs predicted by target prediction algorithms and previously demonstrated as relevant in vulvar carcinomas, such as TP53, RB, PTEN, and EGFR was constructed. Downregulation of both miR-223-5p and miR-19-b1-5p were correlated with the presence of lymph node metastasis; downregulation of miR-100-3p and miR-19-b1-5p were correlated with presence of vascular invasion; overexpression of miR-519b and miR-133a were associated with advanced FIGO staging. In conclusion, our study demonstrates that microRNAs may be clinically important in vulvar carcinomas and our findings may help for further studies on functional implications of miRNA deregulation in this type of cancer.

MicroRNA expression profiles in Kaposi's sarcoma

Kaposi's sarcoma (KS) is a mesenchymal tumor, caused by Human herpesvirus 8 (HHV8) with molecular and cytogenetic changes poorly understood. To gain further insight on the underlying molecular changes in KS, we performed microRNA (miRNA) microarray analysis of 17 Kaposi's sarcoma specimens. Three normal skin specimens were used as controls. The most significant differentially expressed miRNA were confirmed by quantitative reverse transcriptase polymerase chain reaction (RT-PCR). We detected in KS versus normal skin 185 differentially expressed miRNAs, 76 were upregulated and 109 were downregulated. The most significantly downregulated miRNAs were miR-99a, miR-200 family, miR-199b-5p, miR-100 and miR-335, whereas kshv-miR-K12-4-3p, kshv-miR-K12-1, kshv-miR-K12-2, kshv-miR-K12-4-5p and kshv-miR-K12-8 were significantly upregulated. High expression levels of kshv-miR-K12-1 (p = 0.004) and kshv-miR-K12-4-3p (p = 0.001) was confirmed by RT-PCR. The predicted target genes for differentially expressed miRNAs included genes which are involved in a variety of cellular processes such as angiogenesis (i.e. THBS1) and apoptosis (i.e. CASP3, MCL1), suggesting a role for these miRNAs in Kaposi's sarcoma pathogenesis.

Nip the HPV encoded evil in the cancer bud: HPV reshapes TRAILs and signaling landscapes

HPV encoded proteins can elicit ectopic protein–protein interactions that re-wire signaling pathways, in a mode that promotes malignancy. Moreover, accumulating data related to HPV is now providing compelling substantiation of a central role played by HPV in escaping immunosurveillance and impairment of apoptotic response. What emerges is an intricate network of Wnt, TGF, Notch signaling cascades that forms higher-order ligand–receptor complexes routing downstream signaling in HPV infected cells. These HPV infected cells are regulated both extracellularly by ligand receptor axis and intracellularly by HPV encoded proteins and impair TRAIL mediated apoptosis. We divide this review into different sections addressing how linear signaling pathways integrate to facilitate carcinogenesis and compounds that directly or indirectly reverse these aberrant interactions offer new possibilities for therapy in cancer. Although HPV encoded proteins mediated misrepresentation of pathways is difficult to target, improved drug-discovery platforms and new technologies have facilitated the discovery of agents that can target dysregulated pathways in HPV infected cervical cancer cells, thus setting the stage for preclinical models and clinical trials.

A baculovirus-encoded MicroRNA (miRNA) suppresses its host miRNA biogenesis by regulating the exportin-5 cofactor Ran

MicroRNAs have emerged as key players in the regulation of various biological processes in eukaryotes, including host-pathogen interactions. Recent studies suggest that viruses encode miRNAs to manipulate their host gene expression to ensure their effective proliferation, whereas the host limits virus infection by differentially expressing miRNAs that target essential viral genes. Here, we demonstrate that an insect virus, Bombyx mori nucleopolyhedrosis virus (BmNPV), modulates the small-RNA-mediated defense of its host, B. mori, by encoding an miRNA (bmnpv-miR-1) that downregulates the expression of the host GTP-binding nuclear protein Ran, an essential component of the exportin-5-mediated nucleocytoplasmic transport machinery mainly involved in small-RNA transport from the nucleus to the cytoplasm. We demonstrate the sequence-dependent interaction of bmnpv-miR-1 with Ran mRNA using cell culture and in vivo assays, including RNA interference (RNAi) of Ran. Our results clearly show that bmnpv-miR-1 represses Ran, leading to reduction in the host small-RNA population, and consequently, the BmNPV load increases in the infected larvae. Blocking of bmnpv-miR-1 resulted in higher expression levels of Ran and a decrease in BmNPV proliferation. In contrast, blockage of host miRNA, bmo-miR-8, which targets the immediate-early gene of the virus and whose production was repressed upon bmnpv-miR-1 and Ran dsRNA administration, resulted in a significant increase in the virus load in the infected B. mori larvae. The present study provides an insight into one of the evasion strategies used by the virus to counter the host defense for its effective proliferation and has relevance to the development of insect virus control strategies.

Serum microRNA expression profile distinguishes enterovirus 71 and coxsackievirus 16 infections in patients with hand-foot-and-mouth disease

Altered circulating microRNA (miRNA) profiles have been noted in patients with microbial infections. We compared host serum miRNA levels in patients with hand-foot-and-mouth disease (HFMD) caused by enterovirus 71 (EV71) and coxsackievirus 16 (CVA16) as well as in other microbial infections and in healthy individuals. Among 664 different miRNAs analyzed using a miRNA array, 102 were up-regulated and 26 were down-regulated in sera of patients with enteroviral infections. Expression levels of ten candidate miRNAs were further evaluated by quantitative real-time PCR assays. A receiver operating characteristic (ROC) curve analysis revealed that six miRNAs (miR-148a, miR-143, miR-324-3p, miR-628-3p, miR-140-5p, and miR-362-3p) were able to discriminate patients with enterovirus infections from healthy controls with area under curve (AUC) values ranged from 0.828 to 0.934. The combined six miRNA using multiple logistic regression analysis provided not only a sensitivity of 97.1% and a specificity of 92.7% but also a unique profile that differentiated enterovirial infections from other microbial infections. Expression levels of five miRNAs (miR-148a, miR-143, miR-324-3p, miR-545, and miR-140-5p) were significantly increased in patients with CVA16 versus those with EV71 (p<0.05). Combination of miR-545, miR-324-3p, and miR-143 possessed a moderate ability to discrimination between CVA16 and EV71 with an AUC value of 0.761. These data indicate that sera from patients with different subtypes of enteroviral infection express unique miRNA profiles. Serum miRNA expression profiles may provide supplemental biomarkers for diagnosing and subtyping enteroviral HFMD infections.

Reduced miR-100 expression in cervical cancer and precursors and its carcinogenic effect through targeting PLK1 protein

AIM

Although aberrant miRNAs expression has been documented, altered miR-100 expression in cervical cancer and precursor tissues and its carcinogenic effect and mechanism remain unexplored. The aim of our study was to investigate the role of miR-100 alteration in cervical carcinogenesis.

METHODS

The expression of miR-100 was examined by quantitative real-time reverse transcriptase PCR (qRT-PCR) in 125 cervical tissues including normal cervical epithelium, cervical intraepithelial neoplasia (CIN), and cervical cancer, as well as in five cervical cell lines. Through modulating miR-100 expression using miR-100 inhibitor or mimic in vitro, cell growth, cycle and apoptosis were tested separately by MTT or flow cytometry and meanwhile Polo-like kinase1 (PLK1) mRNA and protein expressions were detected by qRT-PCR and immunoblotting. The expression of PLK1 in 125 cervical tissues was also examined by immunohistochemical staining and the correlation between miR-100 and PLK1 expression in the same tissues was analysed. Finally, HPV-16 E6/E7 expression was modulated by gene transfection and subsequently the level of miR-100 was examined by qRT-PCR.

RESULTS

The miR-100 expression showed a significantly and gradually reduced tendency from low-grade CIN, high-grade CIN to cervical cancer tissues and a significant decrease in HPV positive cervical cancer cell lines. The modulation of miR-100 expression remarkably influenced cell proliferation, cycle and apoptosis, as well as the level of PLK1 protein, but not mRNA, in vitro experiments. PLK1 expression was negatively correlated with miR-100 expression in CIN3 and cervical cancer tissues. The modulation of HR-HPV E6/E7 expression did not change miR-100 level.

CONCLUSIONS

The reduced miR-100 expression participates in the development of cervical cancer at least partly through loss of inhibition to target gene PLK1, which probably occurs in a relative late phase of carcinogenesis. HR-HPV E6/E7 may not directly regulate miR-100 expression in cervical cells.

Antiviral effects of human microRNAs and conservation of their target sites

MicroRNAs are small non-coding RNAs that modulate gene expression at post-transcriptional level, playing a crucial role in cell differentiation and development. Recently, some reports have shown that a limited number of mammalian microRNAs also display antiviral effects. This article summarizes the data in the field paying a special attention to the conservation of the microRNA target sequences in the viral populations. This issue is relevant both for the evaluation of the biological significance of the antiviral effects and for the development of microRNA-based strategies for antiviral intervention.

Adenovirus and miRNAs

Adenovirus infection has a tremendous impact on the cellular silencing machinery. Adenoviruses express high amounts of non-coding virus associated (VA) RNAs able to saturate key factors of the RNA interference (RNAi) processing pathway, such as Exportin 5 and Dicer. Furthermore, a proportion of VA RNAs is cleaved by Dicer into viral microRNAs (mivaRNAs) that can saturate Argonaute, an essential protein for miRNA function. Thus, processing and function of cellular miRNAs is blocked in adenoviral-infected cells. However, viral miRNAs actively target the expression of cellular genes involved in relevant functions such as cell proliferation, DNA repair or RNA regulation. Interestingly, the cellular silencing machinery is active at early times post-infection and can be used to control the adenovirus cell cycle. This is relevant for therapeutic purposes against adenoviral infections or when recombinant adenoviruses are used as vectors for gene therapy. Manipulation of the viral genome allows the use of adenoviral vectors to express therapeutic miRNAs or to be silenced by the RNAi machinery leading to safer vectors with a specific tropism. This article is part of a "Special Issue entitled:MicroRNAs in viral gene regulation".

Regulation of cellular miRNA expression by human papillomaviruses

High-risk HPV infection leads to aberrant expression of cellular oncogenic and tumor suppressive miRNAs. A large number of these miRNA genes are downstream targets of the transcription factors c-Myc, p53, and E2F and their expression can therefore be modulated by oncogenic HPV E6 and E7. Cervical cancer represents a unique tumor model for understanding how viral E6 and E7 oncoproteins deregulate the expression of the miR-15/16 cluster, miR-17-92 family, miR-21, miR-23b, miR-34a, and miR-106b/93/25 cluster via the E6-p53 and E7-pRb pathways. Moreover, miRNAs may influence the expression of papillomavirus genes in a differentiation-dependent manner by targeting viral RNA transcripts. Cellular miRNAs affecting HPV DNA replication are of great interest and will be a future focus. We are entering an era focusing on miRNA and noncoding RNA, and the studies on HPV and host miRNA interactions will continue shedding more light on our understanding of the HPV life cycle and the mechanistic underpinnings of HPV-induced oncogenesis. This article is part of a Special Issue entitled: "MicroRNAs in viral gene regulation".

Human microRNA hsa-miR-125a-5p interferes with expression of hepatitis B virus surface antigen

MicroRNAs are small non-coding RNAs that modulate gene expression at post-transcriptional level, playing a crucial role in cell differentiation and development. Recently, some reports have shown that a limited number of mammalian microRNAs are also involved in anti-viral defense. In this study, the analysis of the hepatitis B virus (HBV) genome by the computer program MiRanda led to the identification of seven sites that are potential targets for human liver microRNAs. These sites were found to be clustered in a 995-bp segment within the viral polymerase ORF and the overlapping surface antigen ORF, and conserved among the most common HBV subtypes. The HBV genomic targets were then subjected to a validation test based on cultured hepatic cells (HepG2, HuH-7 and PLC/PRF/5) and luciferase reporter genes. In this test, one of the selected microRNAs, hsa-miR-125a-5p, was found to interact with the viral sequence and to suppress the reporter activity markedly. The microRNA was then shown to interfere with the viral translation, down-regulating the expression of the surface antigen. Overall, these results support the emerging concept that some mammalian microRNAs play a role in virus-host interaction. Furthermore, they provide the basis for the development of new strategies for anti-HBV intervention.

The search for an optimal DNA, RNA, and protein detection by in situ hybridization, immunohistochemistry, and solution-based methods

Clinical trials and correlative laboratory research are increasingly reliant upon archived paraffin-embedded samples. Therefore, the proper processing of biological samples is an important step to sample preservation and for downstream analyses like the detection of a wide variety of targets including micro RNA, DNA and proteins. This paper analyzed the question whether routine fixation of cells and tissues in 10% buffered formalin is optimal for in situ and solution phase analyses by comparing this fixative to a variety of cross linking and alcohol (denaturing) fixatives. We examined the ability of nine commonly used fixative regimens to preserve cell morphology and DNA/RNA/protein quality for these applications. Epstein-Barr virus (EBV) and bovine papillomavirus (BPV)-infected tissues and cells were used as our model systems. Our evaluation showed that the optimal fixative in cell preparations for molecular hybridization techniques was "gentle" fixative with a cross-linker such as paraformaldehyde or a short incubation in 10% buffered formalin. The optimal fixatives for tissue were either paraformaldehyde or low concentration of formalin (5% of formalin). Methanol was the best of the non cross-linking fixatives for in situ hybridization and immunohistochemistry. For PCR-based detection of DNA or RNA, some denaturing fixatives like acetone and methanol as well as "gentle" cross-linking fixatives like paraformaldehyde out-performed other fixatives. Long term fixation was not proposed for DNA/RNA-based assays. The typical long-term fixation of cells and tissues in 10% buffered formalin is not optimal for combined analyses by in situ hybridization, immunohistochemistry, or--if one does not have unfixed tissues--solution phase PCR. Rather, we recommend short term less intense cross linking fixation if one wishes to use the same cells/tissue for in situ hybridization, immunohistochemistry, and solution phase PCR.