The clinical potential of microRNAs

Advances in the role of microRNAs associated with the PI3K/AKT signaling pathway in lung cancer

Cancer has long been a topic of great interest in society and a major factor affecting human health. Breast, prostate, lung, and colorectal cancers are the top four tumor types with the greatest incidence rates in 2020, according to the most recent data on global cancer incidence. Among these, lung cancer had the highest fatality rate. Extensive research has shown that microRNAs, through different signaling pathways, play crucial roles in cancer development. It is considered that the PI3K/AKT signaling pathway plays a significant role in the development of lung cancer. MicroRNAs can act as a tumor suppressor or an oncogene by altering the expression of important proteins in this pathway, such as PTEN and AKT. In order to improve the clinical translational benefit of microRNAs in lung cancer research, we have generalized and summarized the way of action of microRNAs linked with the PI3/AKT signaling pathway in this review through literature search and data analysis.

Size-Controlled DNA Tile Self-Assembly Nanostructures Through Caveolae-Mediated Endocytosis for Signal-Amplified Imaging of MicroRNAs in Living Cells

Signal-amplified imaging of microRNAs (miRNAs) is a promising strategy at the single-cell level because liquid biopsy fails to reflect real-time dynamic miRNA levels. However, the internalization pathways for available conventional vectors predominantly involve endo-lysosomes, showing nonideal cytoplasmic delivery efficiency. In this study, size-controlled 9-tile nanoarrays are designed and constructed by integrating catalytic hairpin assembly (CHA) with DNA tile self-assembly technology to achieve caveolae-mediated endocytosis for the amplified imaging of miRNAs in a complex intracellular environment. Compared with classical CHA, the 9-tile nanoarrays possess high sensitivity and specificity for miRNAs, achieve excellent internalization efficiency by caveolar endocytosis, bypassing lysosomal traps, and exhibit more powerful signal-amplified imaging of intracellular miRNAs. Because of their excellent safety, physiological stability, and highly efficient cytoplasmic delivery, the 9-tile nanoarrays can realize real-time amplified monitoring of miRNAs in various tumor and identical cells of different periods, and imaging effects are consistent with the actual expression levels of miRNAs, ultimately demonstrating their feasibility and capacity. This strategy provides a high-potential delivery pathway for cell imaging and targeted delivery, simultaneously offering a meaningful reference for the application of DNA tile self-assembly technology in relevant fundamental research and medical diagnostics.

Analysis of Rare Alleles of miRNA-146a (rs2910164) and miRNA-34b/c (rs4938723) as a Prognostic Marker in Thyroid Cancer in Pakistani Population

Background: Rationale: The miRNAs are short non-coding functional RNAs that are involved in the regulation of transcriptomes. It was found that human miRNA-146a and miRNA34b/c are important microRNAs and are functioning either as onco-miRNAs, or acting as tumor suppressors, in different conditions. To date, no study has been performed to evaluate the alterations of miRNA-146ars2910164 and miRNA34b/crs4938723 polymorphism as a risk factor in the development of thyroid cancer in the Pakistani population. Mutational analysis of rs2910164 and rs4938723 of miRNA-146a and miRNA-34b/c was carried out to check their association with the development of thyroid carcinogenesis. Material and Methods: Papillary thyroid cancer (PTC) patients with age and gender-matched controls were recruited for the present study. DNA extraction, genotyping of rs2910164 and rs4938723 was carried out by ARMS-PCR. Statistical analyses were carried out using SPSS software (version 20). Results: The odds ratio for risk allele C of rs2910164 for patients and controls was 23.0168 (3.0321−174.7208) with a p-value of <0.0001, showing that the frequency of the major allele G was lower in patients while the frequency of minor allele C was higher in patients. Similarly, the odds ratio for risk allele C of rs4938723 was 1.8621 (1.0321−3.3596) with a p-value of <0.03788 showing significant association with the development of thyroid cancer. Conclusions: The study highlights the significant association of miRNAs SNPs as one of the genetic risk factor for PTC. It was concluded that miRNA-146a (rs2910164) showed higher frequency of minor allele C in patients. Similarly in miRNA-34b/c gene SNP rs4938723 was observed to have a strong association with the development of thyroid cancer as the frequency of rare allele C was higher in patients.

miR-342-5p inhibits odonto/osteogenic differentiation of human dental pulp stem cells via targeting Wnt7b

OBJECTIVE

Human dental pulp stem cells (hDPSCs) constitute a promising source of stem cells in tissue engineering. However, the molecular mechanism of differentiation in hDPSCs remains largely unclear. MicroRNAs (miRNAs) play crucial roles in lineage-specific differentiation of stem cells. The present study investigated the function of miRNA-342-5p in the odonto/osteogenic differentiation of hDPSCs.

METHODS

The miRNA array profiling and quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) revealed the expression of miR-342-5p during odonto/osteogenic differentiation of hDPSCs. hDPSCs were treated with miR-342-5p mimic and inhibitor to investigate the regulatory roles of miR-342-5p in the differentiation of hDPSCs. Moreover, miR-342-5p inhibitor and small interference RNA (siRNA) targeting Wnt7b were applied to explore the regulatory mechanism of miR-342-5p.

RESULTS

Downregulated miR-342-5p was observed during odonto/osteogenic differentiation of hDPSCs. The overexpression of miR-342-5p inhibited the odonto/osteogenic potential of DPSCs, as indicated by low levels of alkaline phosphatase activity, calcium deposition formation, and odonto/osteogenic differentiation markers, whereas silencing of miR-342-5p exhibited the opposite effect. When co-treated with siRNA targeting Wnt7b and miR-342-5p inhibitor in hDPSCs, the odonto/osteogenic potential and activation of Wnt7b/β-catenin pathway were attenuated.

CONCLUSIONS

This study showed that miR-342-5p inhibits the odonto/osteogenic differentiation of hDPSCs by interfering with Wnt/β-catenin signaling via targeting Wnt7b.

Long Non-Coding RNA OIP5-AS1 Inhibits the Proliferation and Migration of Esophageal Squamous Carcinoma Cells by Targeting FOXD1/miR-30a-5p Axis and the Effect of Micro- and Nano-Particles on Targeting Transfection System

Esophageal cancer is one of the most common human malignancies and ranks sixth for global mortality; the major histological type is esophageal squamous cell carcinoma (ESCC). Here we assessed the effect of long non-coding (lnc) RNA OIP5-AS1 on the miR-30a-5p/Forkhead box protein D1 (FOXD1) axis in ESCC and investigated the underlying mechanism involving the ERK1/2 signaling pathway. lnc RNA OIP5-AS1 was highly expressed in human ESCC tissues and cells, targeted miR-30a-5p, and inhibited miR-30a-5p expression. Additionally, in human ESCC tissues, miR-30a-5p was poorly expressed, whereas FOXD1 mRNA and protein were highly expressed, with a negative correlation between miR-30a-5p and FOXD1 expression. miR-30a-5p targeted and inhibited FOXD1 expression. FOXD1 promoted the proliferation and invasion of ESCC and was related to the ERK1/2 signaling pathway; ERK1/2 inhibitors (LY-3214996) reversed the biological function of FOXD1. miR-30a-5p combined with FOXD1 regulated ERK1/2 expression and inhibited tumor growth in vivo. In this study, micro- and nano-particles were used as carriers to construct Nanocapsules carrying miR-30a-5p mimics and miR-30a-5p inhibitor through self-assembly method, so as to realize an efficient Nanocapsules delivery system of miR-30a-5p to esophageal cancer cells. It provides insights into targeted drug therapy and the development of micro- and nano-particles carriers.

Silencing of Long Non-Coding RNA LINC00607 Prevents Tumor Proliferation of Osteosarcoma by Acting as a Sponge of miR-607 to Downregulate E2F6

Osteosarcoma (OS), a type of malignant bone tumor, is commonly found in children and adolescents. Although previous studies have identified that long non-coding RNAs (lncRNAs) regulate OS, it is unclear whether lncRNAs impact the progression of OS. Here, we identified LINC00607, a lncRNA that facilitates OS proliferation, migration, and invasion. Based on the RNA-sequencing results, LINC00607 expression was significantly upregulated in pulmonary metastasis within OS. Functional experiments revealed that LINC00607 promoted migration and invasion of endothelial cells to exacerbate epithelial-mesenchymal transition (EMT). Furthermore, the results of RNA pull-down assay and invasion assay suggested that the binding between LINC00607 and miR-607 promoted OS invasion. Bioinformatic analysis and rescue experiments demonstrated that E2F6, a transcriptional factor, functioned downstream of LINC00607/miR-607. Finally, we found that LINC00607 promoted OS progression in vivo. This work revealed that LINC00607 worked as an miR-607 sponge to upregulate E2F6 expression, which promoted tumor proliferation in OS. These results identified a novel therapeutic target for treating OS.

Recent trends in cancer therapy: A review on the current state of gene delivery

Cancer treatment has been always considered one of the most critical and vital themes of clinical issues. Many approaches have been developed, depending on the type and the stage of tumor. Gene therapy has the potential to revolutionize different cancer therapy. With the advent of recent bioinformatics technologies and genetic science, it become possible to identify, diagnose and determine the potential treatment using the technology of gene delivery. Several approaches have been developed and experimented in vitro and vivo for cancer therapy including: naked nucleic acids based therapy, targeting micro RNAs, oncolytic virotherapy, suicide gene based therapy, targeting telomerase, cell mediated gene therapy, and CRISPR/Cas9 based therapy. In this review, we present a straightforward introduction to cancer biology and occurrence, highlighting different viral and non-viral gene delivery systems for gene therapy and critically discussed the current and various strategies for cancer gene therapy.

Target-triggered entropy-driven amplification system-templated silver nanoclusters for multiplexed microRNA analysis

MicroRNAs (miRNAs) are important biomarkers for the diagnosis, prognosis, and treatment of human diseases. Sensitive and selective detection of multiple miRNAs simultaneously will greatly facilitate the early and accurate diagnosis of cancers. Herein, a novel entropy-driven amplification system-templated silver nanoclusters sensing platform was developed for the multiplexed analysis of tumor-associated miRNAs. The sensing platform was constructed by coupling target-triggered entropy-driven catalysis with luminescence adjustable DNA-templated silver nanoclusters (Ag NCs). In the presence of target miRNA, the sensing platform initiates the branch migration and strand displacement of the complex, which has a six-base cytosine loop for stabilizing the luminous Ag NCs. The target is cyclically generated for new catalysis while turning off the fluorescence of Ag NCs; this is accompanied by a significantly amplified optical readout. In this study, two different complex-stabilized Ag NCs systems were proposed, the yellow-emitting Ag NCs and red-emitting Ag NCs biosensors enabled the analysis of miRNA-141 and miRNA-155 with detection limits of 6.1 pM and 8.7 pM, respectively. Impressively, owing to the excellent selectivity, flexibility, and narrow-band excitation of the platform, the multiplexed synchronous detection of miRNA-141 and miRNA-155 were achieved in buffer, biological cell lysates and human serum samples with satisfactory results. The simple, flexible, and convenient strategy provides a powerful tool for multiple biomarkers analysis and related clinical applications.

The role of microRNAs in ovarian function and the transition toward novel therapeutic strategies in fertility preservation: from bench to future clinical application

BACKGROUND

New therapeutic approaches in oncology have converted cancer from a certain death sentence to a chronic disease. However, there are still challenges to be overcome regarding the off-target toxicity of many of these treatments. Oncological therapies can lead to future infertility in women. Given this negative impact on long-term quality of life, fertility preservation is highly recommended. While gamete and ovarian tissue cryopreservation are the usual methods offered, new pharmacological-based options aiming to reduce ovarian damage during oncological treatment are very attractive. In this vein, advances in the field of transcriptomics and epigenomics have brought small noncoding RNAs, called microRNAs (miRNAs), into the spotlight in oncology. MicroRNAs also play a key role in follicle development as regulators of follicular growth, atresia and steroidogenesis. They are also involved in DNA damage repair responses and they can themselves be modulated during chemotherapy. For these reasons, miRNAs may be an interesting target to develop new protective therapies during oncological treatment. This review summarizes the physiological role of miRNAs in reproduction. Considering recently developed strategies based on miRNA therapy in oncology, we highlight their potential interest as a target in fertility preservation and propose future strategies to make the transition from bench to clinic.

OBJECTIVE AND RATIONALE

How can miRNA therapeutic approaches be used to develop new adjuvant protective therapies to reduce the ovarian damage caused by cytotoxic oncological treatments?

SEARCH METHODS

A systematic search of English language literature using PubMed and Google Scholar databases was performed through to 2019 describing the role of miRNAs in the ovary and their use for diagnosis and targeted therapy in oncology. Personal data illustrate miRNA therapeutic strategies to target the gonads and reduce chemotherapy-induced follicular damage.

OUTCOMES

This review outlines the importance of miRNAs as gene regulators and emphasizes the fact that insights in oncology can inspire new adjuvant strategies in the field of onco-fertility. Recent improvements in nanotechnology offer the opportunity for drug development using next-generation miRNA-nanocarriers.

WIDER IMPLICATIONS

Although there are still some barriers regarding the immunogenicity and toxicity of these treatments and there is still room for improvement concerning the specific delivery of miRNAs into the ovaries, we believe that, in the future, miRNAs can be developed as powerful and non-invasive tools for fertility preservation.

Anti-Micro RNA-221 a Promising Genetic Therapy of Oral Squamous Cell Carcinoma (SCC-25)

Micro-RNA-221(miR-221) is one of oncogenic miRNAs that plays a vital role in the development and progression of oral cancers. The aim of this study is to introduce a new gene therapy for oral squamous cell carcinoma by blocking the expression of oncogenic miR-221 by its inhibitor. The present work was performed on squamous cell carcinoma cell line SCC-25 and anti-miR-221 was delivered to the cells using an ultrasound micro bubbles. Assessment of the effect of miR-221 inhibitor on SCC-25 cells was done using MTT assay, cell cycle analysis and apoptosis detection. In addition, reverse transcription-polymerase chain reaction was also used to detect the expression -miR-221 and its target genes. Using ANOVA, statistical analysis of the results showed significant inhibition of cell viability with and induction of cell apoptosis of SCC-25 cell line after transfection. Moreover, the expression of miR-221, Epidermal growth factor receptor (EGFR) and CDKNIB/p27 were downregulated without significant difference. Transfection of SCC-25 by inhibitor of miR-221 resulting in blockage of its expression leading to arresting of tumor growth. These results proved the effective role of micro-RNA inhibitors as novel therapeutic agent for oral cancers.

Long non-coding RNA UCA1 promotes breast cancer by upregulating PTP1B expression via inhibiting miR-206

Background

The long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) is involved in various cancers and often functions through microRNAs. The pro-survival protein PTP1B is known to play important roles in cancer development. However, the connection between UCA1 and PTP1B in breast cancer is not well studied.

Methods

In this study, we first evaluated the correlation between UCA1 level and PTP1B expression in breast tissues, which showed the expression of PTP1B were much higher in the breast tumor tissues than in the peritumor normal tissues. The UCA1 level was positively associated with PTP1B expression in breast tumor tissues.

Results

We observed that UCA1 could up-regulate PTP1B expression in breast cancer cells. We also found that miR-206 could inhibit the expression of PTP1B by directly binding to the 3′-UTR of its mRNA. Interestingly, UCA1 could increase the expression of PTP1B through sequestering miR-206 at post-transcriptional level. The results also suggested that UCA1-induced PTP1B expression facilitated the proliferation of breast cancer cells.

Conclusions

We conclude that UCA1 can up-regulates PTP1B to enhance cell proliferation through sequestering miR-206 in breast cancer. Our finding provides new insights into the mechanism of breast cancer regulation by UCA1, which could be a potential target for breast cancer treatment.

Trial registration 2012N5hSYSU48573. Registered at Oct 12, 2012

Validation of microRNA expression profile in Oral Lichenoid Disease through cytological samples

Background

To validate oral exfoliative cytology in the analysis of the microRNA expression profile in Oral Lichenoid Disease (OLD).

Material and Methods

The expression of 13 microRNAs identified and presented by our group in a previous study was analyzed in 26 cases, 16 diagnosed as OLD and 10 controls with no oral mucosal pathology. Cytological samples from the oral mucosa obtained using an Orcellex toothbrush were analyzed using RT-qPCR and TaqMan microRNA assays.

Results

The aberrant expression was validated for 2 microRNAs (miR-146a-5p and miR-7-1-3p) of those previously recognized in the biopsy study.

Conclusions

This is the first time that oral exfoliative cytology is validated in a study of the alterations of the expression of microRNAs in OLD. The alteration of miR-146a and miR-7 compared to controls was validated. These microRNAs are associated with both inflammatory and carcinogenic phenomena that are involved in the etiopathogenesis of this potentially malignant oral disorder.

Key words:microRNAs, lichen planus, epigenetics, cytological techniques.

Expression and clinicopathological role of miR146a in thyroid follicular carcinoma

PURPOSE

Dysregulation of microRNA expression has been involved in the development and progression of follicular thyroid carcinoma (FTC). The aim of this work was to study the expression of miRNA146a in FTC and the association with clinicopathological features of the disease.

METHODS

Thirty-eight patients affected by FTC were included in the study. Twenty patients carrying follicular thyroid adenoma (FA) were also enroled as the benign counterpart of FTC. Total RNA including miRNA146a was extracted from formalin-fixed paraffin-embedded (FFPE) pairs of affected/unaffected tissue and its expression was assessed by real-time PCR. Two selected target genes, TRAF6 (tumour necrosis factor receptor-associated factor 6) and IRAK1 (Il-1 receptor-associated kinase 1/2), were also analysed.

RESULTS

miR146a expression in FTC tissue was overall not downregulated in malignant versus unaffected tissue, but its expression was inversely correlated with clinicopathological features of FTCs at diagnosis. A decreased expression of miR146a became apparent in FTC thyroid tissue of widely compared to minimally invasive tumours. However, miR146a expression differences between contralateral unaffected tissue (extra-FTC) and FTC were not observed regardless of clinicopathological features. IRAK1, a known target for miR146a, was upregulated in FTC and the increase was mainly appreciable in Hurtle FTC variant. Unexpectedly, miR146a did not correlate with TRAF6 showing an inverse trend compared to IRAK1 although both genes regulate the activity of nuclear factor- kB (NF-kB).

CONCLUSION

The results of this study indicate that downregulation of miR146a, inversely correlated with clinicopathological features of FTCs at diagnosis and suggest a possible involvement of miR146a in FTC development. IRAK1 over-expression in FTC may be related to tumour development/progression. In vitro experiments are needed to support this hypothesis.

The expression level of hsa-miR-146a-5p in plasma-derived exosomes of patients with diffuse large B-cell lymphoma

Background:

The standard treatment for patients with diffuse large B-cell lymphoma (DLBCL) had been rituximab-based immunochemotherapy. However, the biological and clinical heterogeneity within DLBCL seems to affect treatment outcome. Therefore, the evaluation of miRNA levels might be useful in predicting treatment response and relapse risk. miR-146a is a modulator of innate and acquired immunity and may play an important role in predicting treatment response. The aim of the present study was to compare the expression level of miR-146a in plasma-derived exosomes of responsive DLBCL patients (response to R-CHOP (Rituximab, and Cyclophosphamide, Hydroxydaunorubicin, Oncovine and Prednisone)), refractory DLBCL patients (resistant to R-CHOP), patients receiving R-CHOP, and healthy donors.

Materials and Methods:

After the preparation of plasma and isolation of exosomes, the presence of plasma-derived exosome was confirmed by Zetaseizer, electron microscope, and Western blot. The patients’ medical records were collected and analyzed. The expression level of exosomal miR-146a was evaluated in DLBCL patients and healthy donors using real-time polymerase chain reaction (PCR). The −ΔCt values of miR-146a were compared among responsive patients (n = 17), refractory patients (n = 16), patients receiving R-CHOP therapy (n = 15), and healthy donors (n = 6).

Results:

The presence and size of plasma-derived exosomes were confirmed. Our findings did not show any significant difference in the expression level of exosomal miR-146a between DLBCL patients and healthy donors (P = 0.48). As well, the clinical and histopathological parameters were not correlated with the expression level of exosomal miR-146a or plasma miR-146a. The expression level of plasma miR-146 was lower than the expression level of exosomal miR-146 (P = 0.01).

Conclusion:

Exosomal miR-146a might be useful as a promising “liquid biopsy” biomarker in predicting treatment response and relapse risk; however, we could not find significant differences due to small sample size.

Hepatocellular Carcinoma: Causes, Mechanism of Progression and Biomarkers

Hepatocellular Carcinoma (HCC) is one of the most common malignant tumours in the world. It is a heterogeneous group of a tumour that vary in risk factor and genetic and epigenetic alteration event. Mortality due to HCC in last fifteen years has increased. Multiple factors including viruses, chemicals, and inborn and acquired metabolic diseases are responsible for its development. HCC is closely associated with hepatitis B virus, and at least in some regions of the world with hepatitis C virus. Liver injury caused by viral factor affects many cellular processes such as cell signalling, apoptosis, transcription, DNA repair which in turn induce important effects on cell survival, growth, transformation and maintenance. Molecular mechanisms of hepatocellular carcinogenesis may vary depending on different factors and this is probably why a large set of mechanisms have been associated with these tumours. Various biomarkers including α-fetoprotein, des-γ-carboxyprothrombin, glypican-3, golgi protein-73, squamous cell carcinoma antigen, circulating miRNAs and altered DNA methylation pattern have shown diagnostic significance. This review article covers up key molecular pathway alterations, biomarkers for diagnosis of HCC, anti-HCC drugs and relevance of key molecule/pathway/receptor as a drug target.

MicroRNA-494 acts as a tumor suppressor in pancreatic cancer, inhibiting epithelial-mesenchymal transition, migration and invasion by binding to SDC1

Pancreatic cancer (PC) is the fourth most common cause of cancer‑related mortality in the industrialized world. Emerging evidence indicates that a variety of microRNAs (miRNAs or miRs) are involved in the development of PC. The aim of the present study was to elucidate the mechanisms through which miR‑494 affects the epithelial‑mesenchymal transition (EMT) and invasion of PC cells by binding to syndecan 1 (SDC1). PC tissues and pancreatitis tissues were collected, and the regulatory effects of miR‑494 on SDC1 were validated using bioinformatics analysis and a dual‑luciferase report gene assay. The cell line with the highest SDC1 expression was selected for use in the following experiments. The role of miR‑494 in EMT was assessed by measuring the expression of SDC1, E‑cadherin and vimentin. Cell proliferation was assessed using a cell counting kit (CCK)‑8 assay, migration was measured using a scratch test, invasion was assessed with a Transwell assay and apoptosis was detected by flow cytometry. Finally, a xenograft tumor model was constructed in nude mice to observe tumor growth in vivo. We found that SDC1 protein expression was significantly higher in the PC tissues. SDC1 was verified as a target gene of miR‑494. The SW1990 cell line was selected for use in further experiments as it had the lowest miR‑494 expression and the highest SDC1 expression. Our results also demonstrated that miR‑494 overexpression and SDC1 silencing significantly decreased the mRNA and protein expression of SDC1 and vimentin in SW1990 cells, while it increased E‑cadherin expression and apoptosis, and inhibited cell growth, migration, invasion and tumor growth. On the whole, the findings of this study demonstrated that miR‑494 is able to downregulate SDC1 expression, thereby inhibiting the progression of PC. These findings reveal a novel mechanism through which miR‑494 affects the development of PC and may thus provide a basis for the application of miR‑494 in pancreatic oncology.

Down-regulation of NAMPT expression by mir-206 reduces cell survival of breast cancer cells

Nicotinamide adenine dinucleotide (NAD) is a critical coenzyme for all living cells. Nicotinamide phosphoribosyltransferase (NAMPT) functions as a key enzyme in the salvage pathway of NAD biosynthesis. Cancer cells have higher rate of NAD consumption and therefore NAMPT is essential for their survival. Thus, we investigated the effect of NAMPT inhibition by miR-206 on breast cancer cell survival. Breast cancer cells were transfected with miR-206 mimic, inhibitor and their negative controls. NAMPT levels were assessed by real-time PCR as well as western blotting. Cell survival assay and quantification of NAD level were performed by using colorimetric methods. Apoptosis assay was performed by labeling cells with Annexin V-FITC and propidium iodide followed by the flow cytometric analysis. Bioinformatics analysis was done to assess whether NAMPT 3'-UTR is a direct target of miR-206 and the results were confirmed by the luciferase reporter assay. NAMPT 3'-UTR was shown to be a direct target of miR-206. miR-206 reduced NAMPT expression at the protein level, leading to a significant decrease in the intracellular NAD level and subsequent decline in cell survival and induction of apoptosis. Targeting of NAMPT-mediated NAD salvage pathway by miR-206 might provide a new insight in the possible molecular mechanism of breast cancer cell growth regulation. This pathway might provide a new approach for breast cancer therapy.

New Perspectives on Diagnosis and Therapy of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, but severe form of cancer, with an incidence that varies significantly within and among different countries around the world. It develops in about one to two persons per million of the general population, leading to thousands of deaths every year worldwide. To date, the MPM is mostly associated with occupational asbestos exposure. Asbestos represents the predominant etiological factor, with approximately 70% of cases of MPM with well-documented occupational exposure to asbestos, with the exposure time, on average greater than 40 years. Environmental exposure to asbestos is increasingly becoming recognized as a cause of mesothelioma, together with gene mutations. The possible roles of other cofactors, such as viral infection and radiation exposure, are still debated. MPM is a fatal tumor. This cancer arises during its early phase without clinical signs. Consequently, its diagnosis occurs at advanced stages. Standard clinical therapeutic approaches include surgery, chemo- and radiotherapies. Preclinical and clinical researches are making great strides in the field of this deadly disease, identifying new biomarkers and innovative therapeutic approaches. Among the newly identified markers and potential therapeutic targets, circulating microRNAs and the Notch pathway represent promising avenues that could result in the early detection of the tumor and novel therapeutic approaches.

Serum miRNA-27a and miRNA-18b as potential predictive biomarkers of hepatitis C virus-associated hepatocellular carcinoma

Hepatitis C virus (HCV) infection remains the main risk factor for chronic hepatitis (CHC), liver cirrhosis, and hepatocellular carcinoma (HCC). Changes in microRNA (miRNA) profiles can be associated with HCV infection and may either favor or inhibit the virus and/or its complication. Moreover, miRNAs have emerged as key regulators of various cancers including HCC. The aim of this work was to investigate the potentail role of miRNA-27a and miRNA-18b expression levels as non-invasive predictive biomarkers of hepatitis C virus-associated HCC. Furthermore, we aimed to explore potential association of these miRNAs expressions with HCC clinicopathological features' in Egyptian cases. This case control study included 200 participants [60 CHC patients, 39 post-HCV cirrhosis patients, 51 HCC cases], and 50 healthy volunteers. The serum miRNA-27a and miRNA-18b expression profiles were measured using quantitative real time-polymerase chain reaction (qRT-PCR). miRNA-27a and miRNA-18b expression levels were significantly increased in post-hepatitis C cirrhosis cases compared to control and CHC groups. In HCC group, only miRNA-27a expression levels were significantly increased. Moreover, miRNA-27a and miRNA-18b expression levels were positively correlated with distant metastasis, Child-Pugh grade, and lymph node metastasis. Logistic regression analysis revealed that miRNA-27a expression was an independent predictor of cirrhosis among CHC. Receiver operating characteristic (ROC) analyses showed that miRNA-27a and miRNA-18b expression levels were useful biomarkers discriminating cirrhosis from CHC (AUC were 0.672 and 0.487, respectively), and in differentiating HCC from post-hepatitis C cirrhosis (AUC were 0.897 and 0.723, respectively). By combined ROC analysis, power of miRNA-27a and miRNA-18b expression levels as discriminator between HCC from post-hepatitis C cirrhosis was high (AUC = 0.0.821). Serum microRNA-27a and miRNA-18b expression levels are promising diagnostic and non-invasive biomarkers of CHC, post-CHC cirrhosis, and HCC.

The role of microRNAs in oral lichenoid disorders. Systematic review

Background

Certain changes in the microRNA expression are considered to be associated with chronic inflammatory processes and with the malignant transformation of oral potentially malignant disorders. The purpose of this systematic review is to update the existing data on the aberrant microRNA expression profiles identified in oral lichenoid disease (OLD).

Material and Methods

A search in PubMed-Medline and Scopus was performed on the English literature published between 2010 and August 2016 using the following keywords: oral lichenoid disease, oral lichen planus and microRNA.

Results

Originally, 25 articles were considered, of which 12 case-control articles were selected according to the inclusion/exclusion criteria.

Conclusions

OLD seems to have altered microRNA expression profile. Certain altered microRNAs (146a, 155) may be useful as biomarkers for this disorder. More studies including larger number of cases are needed in order to study further on the biological processes and on the regulation pathways of these altered microRNAs.

Key words:microRNAs, oral lichenoid disease, oral lichen planus.

MicroRNA-16-5p overexpression suppresses proliferation and invasion as well as triggers apoptosis by targeting VEGFA expression in breast carcinoma

MicroRNAs (miRNAs), a class of small noncoding RNA molecules, can manipulate the expressions of endogenous tumor-related genes, and are implicated in the development and progression of a wide type of tumors. In this study, the investigation from real-time quantitative PCR revealed that miRNA-16-5p was downregulated in breast carcinoma tissues and cells, coupled with the elevations of HIF-α and VEGFA protein expressions, compared with normal tissues. Lentiviral armed with miR-16-5p markedly increased the miR-16-5p levels in MCF-7 and MDA-MB-231 cells, compared to blank and NC groups, and miR-16-5p overexpression significantly inhibited the proliferation and colony formation in MCF-7 and MDA-MB-231 cells. Besides, miR-16-5p upregulation markedly induced apoptosis and reduced invasion ability in MCF-7 and MDA-MB-231 cells. Notably, VEGFA was direct target of miR-16-5p. Stepwise investigation from in vitro and in vivo experiments demonstrated that miR-16-5p overexpression suppressed tumor growth and reduced HIF-α and VEGFA expressions in breast carcinoma cells and nude mice tumor tissues. These findings provide novel insights into molecular mechanism involved in the roles of miR-16-5p in tumor development and progression of breast carcinoma, and thus manipulation of miR-16-5p may be a novel potential therapeutic target for future therapies of the patients with breast carcinoma.

MicroRNA-107-5p suppresses non-small cell lung cancer by directly targeting oncogene epidermal growth factor receptor

MicroRNAs (miRNAs) are dysregulated in cancers, including human non-small cell lung cancer (NSCLC). The function of MicroRNA-107-5p (miR-107-5p) in NSCLC is not fully elucidated. Epidermal growth factor receptor (EGFR) is a cancer-driven gene in tumorigenesis. In this study, we found that miR-107-5p was significantly decreased in NSCLC tissues and NSCLC cell lines. Moreover, our results indicated that miR-107-5p could suppress cell proliferation, inhibit metastasis, impede cell cycle, and promote apoptosis via directly targeting EGFR. We also investigated roles of miR-107-5p in vivo. The results showed that it could inhibit tumor growth. Therefore, our study demonstrated that miR-107-5p not only suppressed the progression in NSCLC cells by inhibiting the expression of EGFR, but also could be a promising and a new potential therapeutic target for lung cancer.

Genes directly regulated by NF-κB in human hepatocellular carcinoma HepG2

It has been well-known that over activation of NF-κB has close relationship with hepatitis and hepatocellular carcinoma (HCC). However, the complete and exact underlying molecular pathways and mechanisms still remain not fully understood. By manipulating NF-κB activity with its recognized activator TNFα and using ChIP-seq and RNA-seq techniques, this study identified 699 NF-κB direct target genes (DTGs) in a widely used HCC cell line, HepG2, including 399 activated and 300 repressed genes. In these NF-κB DTGs, 216 genes (126 activated and 90 repressed genes) are among the current HCC gene signature. In comparison with NF-κB target genes identified in LPS-induced THP-1 and TNFα-induced HeLa cells, only limited numbers (24-46) of genes were shared by the two cell lines, indicating the HCC specificity of identified genes. Functional annotation revealed that NF-κB DTGs in HepG2 cell are mainly related with many typical NF-κB-related biological processes including immune system process, response to stress, response to stimulus, defense response, and cell death, and signaling pathways of MAPK, TNF, TGF-beta, Chemokine, NF-kappa B, and Toll-like receptor. Some NF-κB DTGs are also involved in Hepatitis C and B pathways. It was found that 82 NF-κB DTGs code secretory proteins, which include CCL2 and DKK1 that have already been used as HCC markers. Finally, the NF-κB DTGs were further confirmed by detecting the NF-κB binding and expression of 14 genes with ChIP-PCR and RT-PCR. This study thus provides a useful NF-κB DTG list for future studies of NF-κB-related molecular mechanisms and theranostic biomarkers of HCC.

Targeting MicroRNAs in Cancer Gene Therapy

MicroRNAs (miRNAs) are a kind of conserved small non-coding RNAs that participate in regulating gene expression by targeting multiple molecules. Early studies have shown that the expression of miRNAs changes significantly in different tumor tissues and cancer cell lines. It is well acknowledged that such variation is involved in almost all biological processes, including cell proliferation, mobility, survival and differentiation. Increasing experimental data indicate that miRNA dysregulation is a biomarker of several pathological conditions including cancer, and that miRNA can exert a causal role, as oncogenes or tumor suppressor genes, in different steps of the tumorigenic process. Anticancer therapies based on miRNAs are currently being developed with a goal to improve outcomes of cancer treatment. In our present study, we review the function of miRNAs in tumorigenesis and development, and discuss the latest clinical applications and strategies of therapy targeting miRNAs in cancer.

Molecular mechanisms of HPV mediated neoplastic progression

Human Papillomavirus is the major etiological agent in the development of cervical cancer but not a sufficient cause. Despite significant research, the underlying mechanisms of progression from a low-grade squamous intraepithelial lesion to high grade squamous intraepithelial lesion are yet to be understood. Deregulation of viral gene expression and host genomic instability play a central role in virus-mediated carcinogenesis. Key events such as viral integration and epigenetic modifications may lead to the deregulation of viral and host gene expression. This review has summarized the available literature to describe the possible mechanism and role of viral integration in mediating carcinogenesis. HPV integration begins with DNA damage or double strand break induced either by oxidative stress or HPV proteins and the subsequent steps are driven by the DNA damage responses. Inflammation and oxidative stress could be considered as cofactors in stimulating viral integration and deregulation of cellular and viral oncogenes during the progression of cervical carcinoma. All these events together with the host and viral genetic and epigenetic modifications in neoplastic progression have also been reviewed which may be relevant in identifying a new preventive therapeutic strategy. In the absence of therapeutic intervention for HPV-infected individuals, future research focus should be directed towards preventing and reversing of HPV integration. DNA damage response, knocking out integrated HPV sequences, siRNA approach, modulating the selection mechanism of cells harboring integrated genomes and epigenetic modifiers are the possible therapeutic targets.

Switching off malignant mesothelioma: exploiting the hypoxic microenvironment

Malignant mesotheliomas are aggressive, asbestos-related cancers with poor patient prognosis, typically arising in the mesothelial surfaces of tissues in pleural and peritoneal cavity. The relative unspecific symptoms of mesotheliomas, misdiagnoses, and lack of precise targeted therapies call for a more critical assessment of this disease. In the present review, we categorize commonly identified genomic aberrations of mesotheliomas into their canonical pathways and discuss targeting these pathways in the context of tumor hypoxia, a hallmark of cancer known to render solid tumors more resistant to radiation and most chemo-therapy. We then explore the concept that the intrinsic hypoxic microenvironment of mesotheliomas can be Achilles' heel for targeted, multimodal therapeutic intervention.

Targeting MicroRNA in Cancer Using Plant-Based Proanthocyanidins

Proanthocyanidins are oligomeric flavonoids found in plant sources, most notably in apples, cinnamon, grape skin and cocoa beans. They have been also found in substantial amounts in cranberry, black currant, green tea, black tea and peanut skins. These compounds have been recently investigated for their health benefits. Proanthocyanidins have been demonstrated to have positive effects on various metabolic disorders such as inflammation, obesity, diabetes and insulin resistance. Another upcoming area of research that has gained widespread interest is microRNA (miRNA)-based anticancer therapies. MicroRNAs are short non-coding RNA segments, which plays a crucial role in RNA silencing and post-transcriptional regulation of gene expression. Currently, miRNA based anticancer therapies are being investigated either alone or in combination with current treatment methods. In this review, we summarize the current knowledge and investigate the potential of naturally occurring proanthocyanidins in modulating miRNA expression. We will also assess the strategies and challenges of using this approach as potential cancer therapeutics.

Initial research on the relationship between let-7 family members in the serum and massive cerebral infarction

Eighty-eight ischemic stroke patients with massive cerebral infarction (MCI) who met our selection criteria were included in this study. MCI was assessed using the Glasgow Coma Scale (GCS) at hospital admission and at 2 weeks. The sera of all patients and controls were sampled at 48 h after the patients' attacks, and the sera of patients with MCI who had no severe cardiopulmonary complications, including those with hemorrhagic transformation (HT), were sampled again at 2 weeks. The relative expression of let-7 miRNA in the serum was determined by real-time qRT-PCR, and the blood levels of lipids, glucose, high-sensitivity C-reactive protein (hs-CRP), homocysteine and blood pressure were measured at admission. Interleukin-6 (IL-6) levels were detected by ELISA, and a luciferase assay was performed to confirm that IL-6 was a gene target of let-7. The relative expression of let-7f was significantly down-regulated in MCI without HT patients compared with controls (P<0.001), and it was positively correlated with GCS (P<0.01) and negatively correlated with hs-CRP (P<0.01). The relative expression of let-7f was significantly up-regulated in MCI patients with HT (P<0.01). IL-6 is a direct target gene for let-7f, and IL-6 expression was increased in MCI without HT patients compared to controls (P<0.01). The expression of let-7f in serum is associated with MCI without HT, which specifically inhibits IL-6. This suggests that let-7f may control inflammation in patients with MCI without HT.

An Omics Perspective on Molecular Biomarkers for Diagnosis, Prognosis, and Therapeutics of Cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive biliary tract malignancy arising from the epithelial bile duct. The lack of early diagnostic biomarkers as well as therapeutic measures results in severe outcomes and poor prognosis. Thus, effective early diagnostic, prognostic, and therapeutic biomarkers are required to improve the prognosis and prolong survival rates in CCA patients. Recent advancement in omics technologies combined with the integrative experimental and clinical validations has provided an insight into the underlying mechanism of CCA initiation and progression as well as clues towards novel biomarkers. This work highlights the discovery and validation of molecular markers in CCA identified through omics approaches. The possible roles of these molecules in various cellular pathways, which render CCA carcinogenesis and progression, will also be discussed. This paper can serve as a reference point for further investigations to yield deeper understanding in the complex feature of this disease, potentially leading to better approaches for diagnosis, prognosis, and therapeutics.

Key nodes of a microRNA network associated with the integrated mesenchymal subtype of high-grade serous ovarian cancer

Metastasis is the main cause of cancer mortality. One of the initiating events of cancer metastasis of epithelial tumors is epithelial-to-mesenchymal transition (EMT), during which cells dedifferentiate from a relatively rigid cell structure/morphology to a flexible and changeable structure/morphology often associated with mesenchymal cells. The presence of EMT in human epithelial tumors is reflected by the increased expression of genes and levels of proteins that are preferentially present in mesenchymal cells. The combined presence of these genes forms the basis of mesenchymal gene signatures, which are the foundation for classifying a mesenchymal subtype of tumors. Indeed, tumor classification schemes that use clustering analysis of large genomic characterizations, like The Cancer Genome Atlas (TCGA), have defined mesenchymal subtype in a number of cancer types, such as high-grade serous ovarian cancer and glioblastoma. However, recent analyses have shown that gene expression-based classifications of mesenchymal subtypes often do not associate with poor survival. This “paradox” can be ameliorated using integrated analysis that combines multiple data types. We recently found that integrating mRNA and microRNA (miRNA) data revealed an integrated mesenchymal subtype that is consistently associated with poor survival in multiple cohorts of patients with serous ovarian cancer. This network consists of 8 major miRNAs and 214 mRNAs. Among the 8 miRNAs, 4 are known to be regulators of EMT. This review provides a summary of these 8 miRNAs, which were associated with the integrated mesenchymal subtype of serous ovarian cancer.

Expression of cancer stem cell biomarkers as a tool for a correct therapeutic approach to hepatocellular carcinoma

Liver cancer is the fifth most commonly diagnosed malignancy and the second most frequent cause of cancer death in men worldwide. Amongst liver cancers, hepatocellular carcinoma (HCC) represents the major histological subtype and it is one of the most common malignant human tumors worldwide. Research into the molecular biology of hepatocarcinogenesis has identified several biomarkers, which could provide additional informations in order to better understand the biology of HCC. A large number of biomarkers have been shown to have potential predictive significance and a wide variety of molecular markers have been proven to be excellent diagnostic tools for HCC but it is difficult to characterize HCC with a single biomarker. Thus, signatures of a combination of biomarkers may be more valuable for the diagnosis, staging and prognosis of HCC. Specifically, a correlation of HCC-CSCs phenotype to specific hepatic cancer subtypes and to specific clinical and pathological features has not yet been reported in human liver tumors. In this view we will first discuss the possible sources of liver stem cells and their relation with liver cancer development and we will secondly focus on the prognostic significance of clinical and pathological features of HCC.

The immune microenvironment of the colorectal tumor: Involvement of immunity genes and microRNAs belonging to the TH17 pathway

Colorectal cancer is a complex and multifactorial disease. Various factors such as genetic, immunological, epigenetic and environmental constitute minor risk factors with their additive effects contributing to the advent of colorectal cancer. In order to evaluate the role of innate and adaptive immunity in the susceptibility, the presentation and the development of colorectal cancer, we considered an immunogenetic approach on polymorphisms in the TLR4 gene and NOD2/CARD15 gene (receptors of innate immunity) as well as in cytokine genes of the TH17 pathway IL17A, IL17F and cytokine receptor IL23R. Then, we evaluated the expression of microRNAs regulated by TLR4 and NOD2/CARD15 or targeting TLR4, IL17 and proinflammatory cytokines (IL-6, TNF) induced by IL17. Through a case-control study, we showed that the polymorphism of IL17A is associated with its susceptibility to colorectal cancer. Considering the tumor location, we found that the mutated alleles of IL17A, IL17F and IL23R are rather associated with colon cancer and not with rectum cancer. This result confirms that the colon and rectum are two different physiological entities. This study shows that TLR4, IL17A/F and IL23R polymorphisms are involved in the presentation of the disease with regard to tumor architecture, histology, and differentiation, advanced stage of the disease and lymph node and metastasis. Overall, these polymorphisms are associated with a poor prognosis of the disease. Furthermore, in order to evaluate the involvement of epigenetic mechanisms in the occurrence of colorectal cancer, we aimed at analyzing the tumor compared to a normal adjacent tissue and the expression of miRNAs (miR21, miR146a, miR135a, miR147b and miR155) that regulate immunity genes especially the cytokines of the TH17 pathway. This research has shown that microRNAs 21, 135a and 146a are associated with colorectal cancer. Indeed, these three miRs are overexpressed in cancer tissue compared to healthy tissue. These results clearly confirm the involvement of epigenetics in colorectal cancer. In other words, this study reveals the importance of immunity and specifically the TH17 pathway in the development and presentation of colorectal cancer. These results suggest that TLR4, IL17A, IL17F and IL23R polymorphisms as well as the expression of microRNAs that regulate inflammation and the TH17 pathway are associated with the evolution and progression of the colorectal tumor that could be considered as biomarkers in colorectal cancer.

Utility of microRNAs and siRNAs in cervical carcinogenesis

MicroRNAs and siRNAs belong to a family of small noncoding RNAs which bind through partial sequence complementarity to 3'-UTR regions of mRNA from target genes, resulting in the regulation of gene expression. MicroRNAs have become an attractive target for genetic and pharmacological modulation due to the critical function of their target proteins in several signaling pathways, and their expression profiles have been found to be altered in various cancers. A promising technology platform for selective silencing of cell and/or viral gene expression using siRNAs is currently in development. Cervical cancer is the most common cancer in women in the developing world and sexually transmitted infection with HPV is the cause of this malignancy. Therefore, a cascade of abnormal events is induced during cervical carcinogenesis, including the induction of genomic instability, reprogramming of cellular metabolic pathways, deregulation of cell proliferation, inhibition of apoptotic mechanisms, disruption of cell cycle control mechanisms, and alteration of gene expression. Thus, in the present review article, we highlight new research on microRNA expression profiles which may be utilized as biomarkers for cervical cancer. Furthermore, we discuss selective silencing of HPV E6 and E7 with siRNAs which represents a potential gene therapy strategy against cervical cancer.

Serum interferon-related microRNAs as biomarkers to predict the response to interferon therapy in chronic hepatitis C genotype 4

Background

Hepatitis C virus genotype 4 (HCV-4) infection is common in the Middle East and Africa, with an extraordinarily high prevalence in Egypt. MicroRNAs (miRNAs) play an important role in various diseases, including HCV infection. The aim of the present study was to assess serum miR-122, miR-221 and miR-21 expression profiles in HCV-4 patients prior to treatment with HCV-4 combination therapy (pegylated alpha interferon and ribavirin) and to determine whether the miRNAs were associated with the drug response.

Methods

RNA was extracted from pretreatment serum samples, and miR-122, miR-221 and miR-21 levels were measured by quantitative PCR. The results were compared among patients with sustained virological responses (SVR) and non-responders (NR).

Results

The expression levels of miR-21 and miR-122 were significantly different between the SVR and NR groups. Receiver operator characteristic (ROC) analysis revealed that the sensitivity, specificity and positive predictive values of miR-21 were 82.2%, 77.3% and 88.1%, respectively, with a cut-off value of 1.7. The sensitivity, specificity and positive predictive values of miR-122 were 68.9%, 59.1% and 77.5%, respectively, with a cut-off value of 3.5.

Conclusion and Significance

miR-21 and miR-122 might be useful predictors for SVR in HCV-4 patients prior to the administration of combination therapy. A higher predictive response power was obtained for miR-21 than for miR-122. These results should reduce ineffective treatments.

Circulating miR-375 and miR-199a-3p as potential biomarkers for the diagnosis of hepatocellular carcinoma

Aiming to find novel non-invasive biomarkers with high accuracy for the detention of early-stage hepatocellular carcinoma (HCC), we examined the predictive power of two microRNAs (miR; miR-375 and miR-199a-3p) as potential biomarkers in early-stage HCC. A total of 234 serum samples (78 samples from HCC patients, 156 samples from healthy controls) were collected. We measured the levels of the two mature microRNAs (miRNAs) (miR-375 and miR-199a-3p) with probe-based stem-loop quantitative reverse-transcriptase PCR (RT-qPCR) in all subjects. In addition, the correlation between the expression levels of two miRs and clinicopathological factors was explored. Receiver operating characteristic curve (ROC) analyses revealed that the two serum miRs could be promising biomarkers for HCC, with relatively high area under the curve (AUC) values as follows: miR-375, 0. 637 with 95 % confidence interval (CI) of 0.560-0.741; miR-199a-3p, 0. 883 with 95 % CI of 0.827-0.938. Stratified analyses indicated that circulating miR-199a-3p showed better predictive value in patients with long-term drinking. Our data suggested that circulating miR-375 and miR-199a-3p could be a novel serum biomarker for HCC. Nevertheless, further validating and improving study with larger sample should be conducted to confirm our results.

Liver cancer oncogenomics: opportunities and dilemmas for clinical applications

Primary liver cancers are among the most rapidly evolving malignant tumors worldwide. An underlying chronic inflammatory liver disease, which precedes liver cancer development for several decades and frequently creates a pro-oncogenic microenvironment, impairs progress in therapeutic approaches. Molecular heterogeneity of liver cancer is potentiated by a crosstalk between epithelial tumor and stromal cells that complicate translational efforts to unravel molecular mechanisms of hepatocarcinogenesis with a drugable intend. Next-generation sequencing has greatly advanced our understanding of cancer development. With regards to liver cancer, the unprecedented coverage of next-generation sequencing has created a detailed map of genetic alterations and identified key somatic changes such as CTNNB1 and TP53 as well as several previously unrecognized recurrent disease-causing alterations that could contribute to new therapeutic approaches. Importantly, these investigations indicate that a classical oncogene addiction cannot be assumed for primary liver cancer. Therefore, hepatocarcinogenesis can be considered a paradigm suitable for individualized medicine.

MicroRNA-486-5p, which is downregulated in hepatocellular carcinoma, suppresses tumor growth by targeting PIK3R1

Deregulated microRNAs and their roles in carcinogenesis and cancer progression have attracted much attention. In previous studies conducted in our laboratory, the Illumina Solexa massively parallel signature sequencing of miRNomes in nontumor and hepatocellular carcinoma (HCC) tissues revealed that miR-486-5p was significantly downregulated in HCC, but its role in HCC development remains unknown. In this study, miR-486-5p levels in HCC tissues and matched control tissues, and in seven HCC cell lines (QGY-7701, QGY-7703, QGY-7404, SMMC-7721, Huh7, HepG2, and PCL/PRF/5) and human normal liver cells (HL-7702), were tested by real-time quantitative RT-PCR. We found that the level of miR-486-5p was significantly decreased in HCC tissue and in all seven HCC cell lines. Overexpression of miR-486-5p markedly suppressed HCC cell proliferation, migration and invasion in vitro, and inhibited HCC growth in vivo. Mechanistically, miR-486-5p was confirmed to directly target PIK3R1 expression, thereby suppressing phosphatidylinositol 3-kinase-AKT pathway activation, by dual luciferase reporter assay and real-time quantitative RT-PCR and western blot analysis. In addition, PIK3R1 knockdown mimicked the effects of miR-486-5p overexpression by inhibiting HCC growth, migration, and invasion. Furthermore, correlation analysis, Kaplan-Meier estimates and Cox proportional hazard models showed an inverse correlation between miR-486-5p and PIK3R1, as well as a shorter time to recurrence after HCC resection, in patients with lower miR-486-5p expression. Hence, we conclude that miR-486-5p, which is frequently downregulated in HCC, inhibits HCC progression by targeting PIK3R1 and phosphatidylinositol 3-kinase-AKT activation.

Emerging role of microRNAs in major depressive disorder: diagnosis and therapeutic implications

Major depressive disorder (MDD) is a major public health concern. Despite tremendous advances, the pathogenic mechanisms associated with MDD are still unclear. Moreover, a significant number of MDD subjects do not respond to the currently available medication. MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by modulating translation, messenger RNA (mRNA) degradation, or stability of mRNA targets. The role of miRNAs in disease pathophysiology is emerging rapidly. Recent studies demonstrating the involvement of miRNAs in several aspects of neural plasticity, neurogenesis, and stress response, and more direct studies in human postmortem brain provide strong evidence that miRNAs can not only play a critical role in MDD pathogenesis, but can also open up new avenues for the development of therapeutic targets. Circulating miRNAs are now being considered as possible biomarkers in disease pathogenesis and in monitoring therapeutic responses because of the presence and/or release of miRNAs in blood cells as well as in other peripheral tissues. In this review, these aspects are discussed in a comprehensive and critical manner.

MicroRNA expression profiling of diagnostic needle aspirates from surgical pancreatic cancer specimens

Purpose

MicroRNAs (miRNAs) have been widely investigated as potential biomarkers for several malignancies. To establish the feasibility of miRNA expression profiling of small biopsy samples of pancreatic cancers, we assessed expression profiles in freshly collected aspirates obtained immediately after surgical resection of the pancreas.

Methods

We used separate fine needles (20-23 gauge) to aspirate the pancreatic cancer and adjacent normal pancreatic tissue. miRNAs that were differentially expressed in pancreatic cancers and matched paraneoplastic normal pancreatic tissues were identified using an miRNA microarray.

Results

We identified 158 aberrantly expressed miRNAs in pancreatic cancers; 51 were overexpressed and 107 underexpressed compared with normal pancreatic tissue. To confirm the microarray findings, quantitative RT-PCR was performed on individual samples. We chose eight miRNAs for further analysis; of which five were overexpressed (miR-21, miR-27a, miR-146a, miR-200a, and miR-196a) and three underexpressed (miR-217, miR-20a, and miR-96) in pancreatic cancer samples compared to benign pancreatic tissue. Expression of miR-21, miR-27a, miR-146a, miR-200a, and miR-196a was significantly increased in cancer fine-needle aspirates relative to matched controls in all samples. Expression of miR-217, miR-20a, and miR-96 was significantly downregulated in almost all pancreatic cancer tissues.

Conclusion

We demonstrate the feasibility of performing miRNA profiling on very small specimens obtained using fine-needle aspiration of pancreatic cancers.

MicroRNA signatures as biomarkers and therapeutic target for CNS embryonal tumors: the pros and the cons

Embryonal tumors of the central nervous system represent a heterogeneous group of childhood cancers with an unknown pathogenesis; diagnosis, on the basis of histological appearance alone, is controversial and patients’ response to therapy is difficult to predict. They encompass medulloblastoma, atypical teratoid/rhabdoid tumors and a group of primitive neuroectodermal tumors. All are aggressive tumors with the tendency to disseminate throughout the central nervous system. The large amount of genomic and molecular data generated over the last 5–10 years encourages optimism that new molecular targets will soon improve outcomes. Recent neurobiological studies have uncovered the key role of microRNAs (miRNAs) in embryonal tumors biology and their potential use as biomarkers is increasingly being recognized and investigated. However the successful use of microRNAs as reliable biomarkers for the detection and management of pediatric brain tumors represents a substantial challenge. This review debates the importance of miRNAs in the biology of central nervous systemembryonal tumors focusing on medulloblastoma and atypical teratoid/rhabdoid tumors and highlights the advantages as well as the limitations of their prospective application as biomarkers and candidates for molecular therapeutic targets.

Modulation of miR-29 expression by α-fetoprotein is linked to the hepatocellular carcinoma epigenome

Globally, hepatocellular carcinoma (HCC) accounts for 70%-85% of primary liver cancers and ranks as the second leading cause of male cancer death. Serum alpha-fetoprotein (AFP), normally highly expressed in the liver only during fetal development, is reactivated in 60% of HCC tumors and associated with poor patient outcome. We hypothesize that AFP+ and AFP- tumors differ biologically. Multivariable analysis in 237 HCC cases demonstrates that AFP level predicts poor survival independent of tumor stage (P<0.043). Using microarray-based global microRNA (miRNA) profiling, we found that miRNA-29 (miR-29) family members were the most significantly (P<0.001) down-regulated miRNAs in AFP+ tumors. Consistent with miR-29's role in targeting DNA methyltransferase 3A (DNMT3A), a key enzyme regulating DNA methylation, we found a significant inverse correlation (P<0.001) between miR-29 and DNMT3A gene expression, suggesting that they might be functionally antagonistic. Moreover, global DNA methylation profiling reveals that AFP+ and AFP- HCC tumors have distinct global DNA methylation patterns and that increased DNA methylation is associated with AFP+ HCC. Experimentally, we found that AFP expression in AFP- HCC cells induces cell proliferation, migration, and invasion. Overexpression of AFP, or conditioned media from AFP+ cells, inhibits miR-29a expression and induces DNMT3A expression in AFP- HCC cells. AFP also inhibited transcription of the miR-29a/b-1 locus, and this effect is mediated through c-MYC binding to the transcript of miR-29a/b-1. Furthermore, AFP expression promotes tumor growth of AFP- HCC cells in nude mice.

CONCLUSION

Tumor biology differs considerably between AFP+ HCC and AFP- HCC; AFP is a functional antagonist of miR-29, which may contribute to global epigenetic alterations and poor prognosis in HCC.

Molecular pathogenesis of intrahepatic cholangiocarcinoma

Cholangiocarcinoma (CCA) is an orphan cancer of the hepatobiliary tract, the incidence of which has increased in the past decade. The molecular pathogenesis of this treatment-refractory disease is poorly understood. Desmoplasia is a key causal feature of CCA; however, a majority of tumors develop with no apparent etiological background. The impact of the stromal compartment on tumor progression as well as resistance to therapy is in vogue, and the epithelial-stromal crosstalk may present a target for novel treatment strategies. As such, the complexity of tumor cellularity and the molecular mechanisms underlying the diversity of growth patterns of this malignancy remain a clinical concern. It is crucial to advance our present understanding of the molecular pathogenesis of CCA to improve current clinical strategies and patient outcome. This will facilitate the delineation of patient subsets and individualization for precision therapies. Many questions persevere as to the evolutionary process and cellular origin of the initial transforming event, the context of intratumoral plasticity and the causal driver action. Next-generation sequencing has begun to underline the persistent alterations, which may be the trigger of acquired drug resistance, and the cause of metastasis and disease recurrence. A complex issue that remains is to account for the heterogeneous pool of "backseat" aberrations, which in chromosomal proximity to the causative variant are likely to influence, for example, drug response. This review explores the recent advances in defining the molecular pathways implicated in the development of this devastating disease and, which present putative clinical strategies.

lincRNA HOTAIR as a novel promoter of cancer progression

Large intergenic non-coding RNAs (lincRNA) regulate development and disease via interactions with their protein partners. Expression of the lincRNA HOX transcript antisense RNA (HOTAIR) is elevated in a variety of malignancies and linked to metastasis and poor prognosis. HOTAIR promotes proliferation, invasion, and metastasis in the preclinical studies of cancer through modulation of chromatin modifying complexes. In the current review we discuss the molecular mechanisms of HOTAIR-mediated aggressive phenotypes of cancer, HOTAIR's potential in cancer intervention, and challenges in exploration of HOTAIR in cancer biology.

MicroRNAs 146a and 147b biomarkers for colorectal tumor's localization

The recently identified class of microRNAs (miRs) provided a new insight into cancer research, since abnormalities of members of microRNAs family have been found in various types of cancer. However, the relationship between five miRNAs (miR146a, miR155, miR21, miR135a, and miR147b) and colorectal cancer remains unclear. In the present study, we examined expression of these miRNAs in 25 pair-matched colon cancer tissues and normal colon mucosa. The expression levels of miR146a, miR155, miR21, miR135a, and miR147b were quantified by real-time PCR. We found that miR21, miR146a, and miR135a were all expressed at higher levels in colon tumors. On the other hand, miR146a and miR147b expressions are significantly higher in left colon compared to right colon. These two miRs, especially miR146a, seemed to be markers for the left colon tumors. Moreover, significant proportional and inverse correlations were found between miR expressions in tumor and healthy tissue, and the correlations profiles were different depending on cancer localization. Taken together, these results lead us to suggest the presence of different mechanisms regulating miRs expression and consequently their target genes in left and right colon. So the pathway of colorectal carcinogenesis would be different according to the site of the tumor.

Overexpression of SLC25A38 protein on acute lymphoblastic leukemia cells

SLC25A38 is a recently identified protein that belongs to the mitochondrial solute carrier family, SLC25. Previous studies have shown that it is a pro-apoptotic protein, which regulates intrinsic caspase-dependent apoptosis. In order to clarify the effect of SLC25A38 protein expression on acute lymphoblastic leukemia (ALL) cells, we detected the expression of SLC25A38 in various cell lines (RPMI 8226, U266, Molt-4 and Jurkat) by western blot analysis. The results indicate that SLC25A38 is highly expressed in the four cell lines. Among 55 leukemia patients (adult, n=32 and infant, n=23), a high expression of SLC25A38 protein was observed in seven infant (7/23, 30.4%) and 15 adult (15/32, 46.9%) ALL patients. Two adult ALL patients that were positive for SLC25A38 were analyzed and the level of SLC25A38 significantly reduced or disappeared following combined chemotherapy, however, reappeared upon ALL recurrence. The expression level was identified to be associated with the proportion of blast cells in the bone marrow. Additionally, SLC25A38 and Notch1 were co-expressed in the four cell lines and the ALL patient samples. The present results show that expression of SLC25A38 is a common feature of ALL cells and may be a novel biomarker for diagnosis, as well as a potential therapeutic target for ALL.

Post-transcriptional regulatory network of epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions

Epithelial-to-mesenchymal transition (EMT) and its reverse process, mesenchymal-to-epithelial transition (MET), play important roles in embryogenesis, stem cell biology, and cancer progression. EMT can be regulated by many signaling pathways and regulatory transcriptional networks. Furthermore, post-transcriptional regulatory networks regulate EMT; these networks include the long non-coding RNA (lncRNA) and microRNA (miRNA) families. Specifically, the miR-200 family, miR-101, miR-506, and several lncRNAs have been found to regulate EMT. Recent studies have illustrated that several lncRNAs are overexpressed in various cancers and that they can promote tumor metastasis by inducing EMT. MiRNA controls EMT by regulating EMT transcription factors or other EMT regulators, suggesting that lncRNAs and miRNA are novel therapeutic targets for the treatment of cancer. Further efforts have shown that non-coding-mediated EMT regulation is closely associated with epigenetic regulation through promoter methylation (e.g., miR-200 or miR-506) and protein regulation (e.g., SET8 via miR-502). The formation of gene fusions has also been found to promote EMT in prostate cancer. In this review, we discuss the post-transcriptional regulatory network that is involved in EMT and MET and how targeting EMT and MET may provide effective therapeutics for human disease.

MicroRNAs and human diseases: diagnostic and therapeutic potential

MicroRNAs (miRNAs) are endogenous, non-coding small RNAs that regulate gene expression at the post-transcriptional level. Recent studies have shown that miRNAs are aberrantly expressed in various human diseases, ranging from cancer to cardiovascular hypertrophy. The expression profiles of the miRNAs clearly differentiate the normal from the pathological state and thus their potential as novel biomarkers in the diagnosis and prognosis of several human diseases is immense. Emerging data on the role of miRNAs in the pathogenesis of various human diseases have paved the way to test their ability to act as novel therapeutic tools. In the present review, we will explore the current knowledge about the role of miRNAs in various human diseases. In addition, we will focus on the emerging evidences demonstrating the potential of miRNAs as novel biomarkers and the strategies to use them as therapeutic tools.