MicroRNA maturation and human disease

MicroRNA-1 targets ribosomal protein genes to regulate the growth, development and reproduction of Schistosoma japonicum

Eggs laid by mature female schistosomes are primarily responsible for the pathogenesis of schistosomiasis and critical for transmission. Consequently, elucidating the mechanism of sexual maturation as well as egg production may lead to new strategies for the control of schistosomiasis. MicroRNAs (miRNAs) are involved in multiple biological processes including reproduction in many organisms, yet their roles have not been well characterized in schistosomes. Here, we investigated microRNA-1 (miR-1), which was downregulated gradually in both male and female Schistosoma japonicum after they reached sexually maturity. The expression of miR-1, as shown with quantitative reverse transcription PCR (qRT-PCR), was lower in the reproductive organs of adult females compared with the somatic tissues. Overexpression of miR-1 in adult worms destroyed the morphological architecture of reproductive organs and reduced the subsequent oviposition, which may be due to the activation of apoptosis pathways. Through in silico analysis, 34 potential target genes of miR-1 were identified, including five ribosomal protein genes, called rp-s13, rp-l7ae, rp-l14, rp-l11 and rp-s24e. In vitro dual-luciferase reporter gene assays and miRNA overexpression experiments further validated that these ribosomal protein genes were directly regulated by miR-1. In contrast to the gene expression of miR-1, qRT-PCR and in situ hybridization experiments demonstrated these ribosomal protein genes were enriched in the sexual organs of adult females. Using RNA interference to silence the ribosomal protein genes in different developmental stages in a mouse model system, we demonstrated that these miR-1 target genes not only participated in the reproductive development of S. japonicum, but also were required for the growth and survival of the parasite in the early developmental stages. Taken together, our data suggested that miR-1 may affect the growth, reproduction and oviposition of S. japonicum by targeting the ribosomal protein genes, which provides insights for exploration of new anti-schistosome strategies.

Identification of key microRNAs regulating ELOVL6 and glioblastoma tumorigenesis

ELOVL fatty acid elongase 6 (ELOVL6) controls cellular fatty acid (FA) composition by catalyzing the elongation of palmitate (C16:0) to stearate (C18:0) and palmitoleate (C16:1n-7) to vaccinate (C18:1n-7). Although the transcriptional regulation of ELOVL6 has been well studied, the post-transcriptional regulation of ELOVL6 is not fully understood. Therefore, this study aims to evaluate the role of microRNAs (miRNAs) in regulating human ELOVL6. Bioinformatic analysis identified five putative miRNAs: miR-135b-5p, miR-135a-5p, miR-125a-5p, miR-125b-5p, and miR-22-3p, which potentially bind ELOVL6 3'-untranslated region (UTR). Results from dual-luciferase assays revealed that these miRNAs downregulate ELOVL6 by directly interacting with the 3'-UTR of ELOVL6 mRNA. Moreover, miR-135b-5p and miR-135a-5p suppress cell proliferation and migration in glioblastoma multiforme cells by inhibiting ELOVL6 at the mRNA and protein levels. Taken together, our results provide novel regulatory mechanisms for ELOVL6 at the post-transcriptional level and identify potential candidates for the treatment of patients with glioblastoma multiforme.

MicroRNAs: Small molecules with big impacts in liver injury

A type of small noncoding RNAs known as microRNAs (miRNAs) fine-tune gene expression posttranscriptionally by binding to certain messenger RNA targets. Numerous physiological processes in the liver, such as differentiation, proliferation, and apoptosis, are regulated by miRNAs. Additionally, there is growing evidence that miRNAs contribute to liver pathology. Extracellular vesicles like exosomes, which contain secreted miRNAs, may facilitate paracrine and endocrine communication between various tissues by changing the gene expression and function of distal cells. The use of stable miRNAs as noninvasive biomarkers was made possible by the discovery of these molecules in body fluids. Circulating miRNAs reflect the conditions of the liver that are abnormal and may serve as new biomarkers for the early detection, prognosis, and evaluation of liver pathological states. miRNAs are appealing therapeutic targets for a range of liver disease states because altered miRNA expression is associated with deregulation of the liver's metabolism, liver damage, liver fibrosis, and tumor formation. This review provides a comprehensive review and update on miRNAs biogenesis pathways and mechanisms of miRNA-mediated gene silencing. It also outlines how miRNAs affect hepatic cell proliferation, death, and regeneration as well as hepatic detoxification. Additionally, it highlights the diverse functions that miRNAs play in the onset and progression of various liver diseases, including nonalcoholic fatty liver disease, alcoholic liver disease, fibrosis, hepatitis C virus infection, and hepatocellular carcinoma. Further, it summarizes the diverse liver-specific miRNAs, illustrating the potential merits and possible caveats of their utilization as noninvasive biomarkers and appealing therapeutic targets for liver illnesses.

Exosomes derived from microRNA-129-5p-modified tumor cells selectively enhanced suppressive effect in malignant behaviors of homologous colon cancer cells

Exosome-encapsulated microRNAs (miRNAs) are novel diagnostic and predictive markers in colon cancer. Hence, the study of serum exosomal miRNAs in patients with colon cancer may help its diagnosis and treatment. PKH26-labeled exosomal uptake analysis identified whether exosomes transfer miRNA-129-5p to target cells. Transmission electron microscopy and dynamic light scattering analysis were applied to determine exosome morphology and size distribution. The Cell Counting Kit-8, wound healing assay and Transwell assays were used to detect cell proliferation, migration, and invasion after treatment with engineered exosomes. Moreover, the Western blotting was used to quantify the expression of proteins involved in cell apoptosis. In our study, hepatocellular liver carcinoma, cervical cancer and colon cancer cells were selected as the target cells of miRNA-129-5p exosomes. Exosomes containing miRNA-129-5p were found to be significantly more easily absorbed by colon cancer cells, presenting a stronger inhibitory effect on colon cancer cell proliferation. MiRNA-129-5p exosomes induced apoptosis in colon cancer cells while inhibiting their proliferation, migration, and invasion. In conclusion, exosomes derived from miRNA-129-5p-modified tumor cells selectively inhibited colon cancer progression, shedding new insights to therapeutic efficacy of this cancer.

Long non-coding RNA EWSAT1 promoted metastasis and actin cytoskeleton changes via miR-24-3p sponging in osteosarcoma

Non‐coding RNAs are closely associated with tumorigenesis in multiple malignant tumours, including osteosarcoma (OS). Long non‐coding RNA Ewing sarcoma‐associated transcript 1 (EWSAT1) plays a role in metastasis, and actin cytoskeletal changes in OS remain unclear. In the current study, we showed that EWSAT1 expression was up‐regulated in OS and that an elevation in the EWSAT1 expression level was correlated with poor prognosis in patients with OS. Functionally, we showed that knockdown of EWSAT1 suppressed migration and induced actin stress fibre degradation in MNNG/HOS and 143B cells. Moreover, we found that ROCK1 was a key downstream effector in EWSAT1‐mediated cell migration and actin stress fibre changes. Furthermore, we demonstrated that ROCK1 and EWSAT1 shared a similar microRNA response element of microRNA‐24‐3p (miR‐24‐3p). Moreover, we verified that miR‐24‐3p suppressed ROCK1 and its mediated migration and actin stress fibres change by direct targeting. EWSAT1 promoted ROCK1‐mediated migration and actin stress fibre formation through miR‐24‐3p sponging. Lastly, through an in vivo study, we demonstrated that EWSAT1 promoted lung metastasis in OS. According to the above‐mentioned results, we suggest that EWSAT1 acts as an oncogene and that EWSAT1/miR‐24‐3p/ROCK1 axial could be a new target in the treatment of OS.

miR-1272 Exerts Tumor-Suppressive Functions in Prostate Cancer via HIP1 Suppression

The development of novel therapies or the improvement of currently used approaches to treat prostate cancer (PCa), the most frequently diagnosed male tumor in developed countries, is an urgent need. In this regard, the functional characterization of microRNAs, molecules shown to regulate a number of cancer-related pathways, is instrumental to their possible clinical exploitation. Here, we demonstrate the tumor-suppressive role of the so far uncharacterized miR-1272, which we found to be significantly down-modulated in PCa clinical specimens compared to normal tissues. Through a gain-of-function approach using miRNA mimics, we showed that miR-1272 supplementation in two PCa cell models (DU145 and 22Rv1) reverted the mesenchymal phenotype by affecting migratory and invasive properties, and reduced cell growth in vitro and in vivo in SCID mice. Additionally, by targeting HIP1 encoding the endocytic protein HIP1, miR-1272 balanced EGFR membrane turnover, thus affecting the downstream AKT/ERK pathways, and, ultimately, increasing PCa cell response to ionizing radiation. Overall, our results show that miR-1272 reconstitution can affect several tumor traits, thus suggesting this approach as a potential novel therapeutic strategy to be pursued for PCa, with the multiple aim of reducing tumor growth, enhancing response to radiotherapy and limiting metastatic dissemination.

Long noncoding RNA KCNQ1OT1 promotes proliferation, migration, and invasion in maxillary sinus squamous cell carcinoma by regulating miR-204/EphA7 axis

Long noncoding RNAs have been demonstrated to contribute to the development and progression of various cancers. However, the underlying regulatory mechanisms of KCNQ1OT1 in tumorigenesis of maxillary sinus squamous cell carcinoma (MSSCC) remain unknown. Herein, we found that KCNQ1OT1 expression was markedly upregulated in MSSCC tissues and MSSCC cell line (IMC-3) by using quantitative reverse transcription-polymerase chain reaction. Loss-of-function experiments revealed that the deletion of KCNQ1OT1 inhibited cell proliferation, migration, and invasion. Moreover, we confirmed KCNQ1OT1 could directly interact with miR-204 by bioinformatic prediction and dual luciferase assay, and miR-204 inhibitor markedly reversed MSSCC tumor phenotypes induced by shKCNQ1OT1. Finally, we demonstrated that KCNQ1OT1/miR-204 facilitated MSSCC progression by regulating Eph receptor A7 (EphA7). Taken together, these results revealed a novel regulatory mechanism KCNQ1OT1/miR-204/EphA7 axis, which could provide a new understanding of MSSCC tumorigenesis and develop potential targets for MSSCC therapy.

Overexpression of microRNA-620 facilitates the resistance of triple negative breast cancer cells to gemcitabine treatment by targeting DCTD

Patients with triple negative breast cancer (TNBC) have a poor survival rate following chemotherapy due to drug resistance. Notably, the molecular mechanism of drug resistance remains elusive. Between December 2011 and December 2014, 36 TNBC samples were obtained from Liaocheng People's Hospital. Three gemcitabine-resistant MDA-MB-231 cell lines (MDA-MB-231rGEM1, MDA-MB-231rGEM2 and MDA-MB-231rGEM3) were obtained by exposure of MDA-MB-231 cells to increasing concentrations of gemcitabine for >12 months. Reverse transcription-quantitative polymerase chain reaction was performed to detect the expression levels of specific genes, including microRNA (miR)-620, ATP-binding cassette sub-family B member 1 (ABCB1), ABCC10, cytidine monophosphate kinase, deoxycytidine monophosphate deaminase (DCTD), nucleoside diphosphate kinase 1 (NME1), ribonucleoside-diphosphate reductase large subunit (RRM1) and RRMB2. Western blot analysis was performed to assess the protein expression levels of DCTD. Furthermore, cell proliferation was assessed using a Cell Counting Kit-8 assay and cell apoptosis was detected using an Annexin V/Dead Cell Apoptosis kit. Interactions between miR-620 and DCTD were predicted using TargetScan and detected with the dual luciferase reporter assay. Elevation of miR-620 expression levels were detected in two of the assessed gemcitabine-resistant MDA-MB-231 cell lines compared with MDA-MB-231 cells. Gemcitabine induced significant elevation of miR-620 in MDA-MB-231 cells. An increase of DCTD at mRNA and protein expression levels in MDA-MB-231rGEM1 cells was observed compared with those in MDA-MB-231 cells. Results suggested that DCTD was directly regulated by miR-620. Inhibition of miR-620 and overexpression of DCTD reversed gemcitabine resistance in MDA-MB-231rGEM1 cells via inducing cell apoptosis and cell growth arrest. A negative correlation was identified between miR-620 and DCTD mRNA expression levels in patients with TNBC. The present results demonstrated that overexpression of miR-620 could contribute to the development of gemcitabine resistance in patients with TNBC via the direct downregulation of DCTD.

PELI3 mediates pro-tumor actions of down-regulated miR-365a-5p in non-small cell lung cancer

Background

To analyze the relative expression of PELI3 and its mechanistic involvement in the non-small cell lung cancer (NSCLC).

Methods

PELI3 expression in NSCLC tissue samples was determined by the immunohistochemistry. The transcripts abundance of PELI3 was measured with real-time PCR. The protein intensity was analyzed by western blot. The overall survival in respect to PELI3 or miR-365a-5p expression was plotted by the Kaplan–Meier’s analysis. Cell growth was determined by colony formation assay. Cell viability was measured by MTT assay. The migration and invasion were evaluated by wound healing and transwell assay respectively. The regulatory effect of miR-365a-5p on PELI3 was interrogated with luciferase reporter assay. The direct binding between miR-365a-5p and PELI3 was analyzed by pulldown assay.

Results

PELI3 was aberrantly up-regulated in NSCLC both in vivo and in vitro. High level of PELI3 associated with poor prognosis. PELI3-deficiency significantly inhibited cell viability, colony formation, migration and invasion. We further identified that miR-365a-5p negatively regulated PELI3 in this disease. Ectopic expression of miR-365a-5p in both A549 and H1299 phenocopied PELI3-deficiency. Meanwhile, PELI3-silencing significantly abolished the pro-tumoral effect elicited by miR-365a-5p inhibition.

Conclusion

Our results highlighted the importance of dysregulated miR-365a-5p-PELI3 signaling axis in NSCLC.

Genome-wide profiling reveals novel microRNAs in hand-spinning-specific chrysotile exposure

Aim: We aimed to explore miRNA expression profiles in hand-spinning chrysotile exposed workers and their potential influencing factors. Methods: miRNA array technique was applied to screen differentially expressed miRNAs between plasma samples from three exposed workers and three controls. Then, seven selected miRNAs were validated in 143 workers and 100 controls, and the potential influencing factors were revealed by multiple linear regression. Finally, the expression levels of those seven miRNAs were evaluated in human mesothelial cells (Met-5A) that were exposed to chrysotile at 5 μg·cm-2 for 8, 24 and 48 h, respectively. Results & conclusion: Hand-spinning chrysotile exposure can result in differential expression of miRNAs. Several of those miRNAs have positive correlations with asbestos exposure.

Ciphers and Executioners: How 3'-Untranslated Regions Determine the Fate of Messenger RNAs

The sequences and structures of 3'-untranslated regions (3'UTRs) of messenger RNAs govern their stability, localization, and expression. 3'UTR regulatory elements are recognized by a wide variety of trans-acting factors that include microRNAs (miRNAs), their associated machinery, and RNA-binding proteins (RBPs). In turn, these factors instigate common mechanistic strategies to execute the regulatory programs encoded by 3'UTRs. Here, we review classes of factors that recognize 3'UTR regulatory elements and the effector machineries they guide toward mRNAs to dictate their expression and fate. We outline illustrative examples of competitive, cooperative, and coordinated interplay such as mRNA localization and localized translation. We further review the recent advances in the study of mRNP granules and phase transition, and their possible significance for the functions of 3'UTRs. Finally, we highlight some of the most recent strategies aimed at deciphering the complexity of the regulatory codes of 3'UTRs, and identify some of the important remaining challenges.

MiR‑495 suppresses cell proliferation by directly targeting HMGA2 in lung cancer

The present study aimed to investigate the expression of microRNA-495 (miR-495) in non-small cell lung cancer (NSCLC) tissues and cells, as well as its function on the proliferation of lung cancer cells. The expression of miR-495 in 122 pairs of NSCLC tissues and matched paracarcinoma tissues, as well as in human lung cancer cell lines (A549, H460, H1650, H520 and SK-MES-1) and the normal human pulmonary bronchial epithelial cell line 16HBE was determined using reverse transcription quantitative polymerase chain reaction (RT-qPCR). As predicted by bioinformatics analysis, high mobility group A2 (HMGA2) may be a potential target gene of miR-495. In addition, the regulatory function of miR-495 on its target gene HMGA2 was evaluated using a dual-luciferase reporter assay, RT-qPCR and western blotting. Furthermore, the effect of miR-495 on the proliferation of A549 lung cancer cells was investigated using a Cell Counting Kit-8 (CCK-8) assay. The results demonstrated that the expression of miR-495 in NSCLC tissues and cells was significantly downregulated compared with the control. In addition, downregulated expression of miR-495 was associated with tumor differentiation, lymph node metastasis and tumor, node and metastasis staging. Additionally, a dual-luciferase reporter assay revealed that miR-495 could directly associated with the 3′-untranslated region of HMGA2. Upregulated expression of miR-495 significantly downregulated the mRNA and protein expression levels of HMGA2 in A549 cells. Furthermore, the results of CCK-8 assay revealed that upregulated expression of miR-495 significantly suppressed the proliferation of A549 cells; HMGA2 overexpression reversed this inhibition. In summary, the findings of the present study demonstrated that miR-495 was downregulated in NSCLC tissues and cells. In addition, miR-495 suppressed the proliferation of lung cancer cells by directly targeting HMGA2.

MORC4 is a novel breast cancer oncogene regulated by miR-193b-3p

A better understanding of breast cancer pathogenesis would contribute to improved diagnosis and therapy and potentially decreased mortality rates. Here, we found that the MORC family CW-type zinc finger 4 (MORC4) overexpression in breast cancer tissues is associated with poor survival, and the short-interfering RNA knockdown of MORC4 suppresses the growth of breast cancer cells by promoting apoptosis. To investigate the mechanisms associated with MORC4 upregulation, microRNAs potentially targeting MORC4 were analyzed, with miR-193b-3p identified as the regulator and a negative correlation between miR-193b-3p and MORC4 expression determined in both breast cancer cell lines and tissues. Further analysis verified that MORC4 silencing did not affect miR-193b-3p expression, although altered miR-193b-3p expression attenuated MORC4 protein levels. Moreover, dual-luciferase reporter assays verified miR-193b-3p binding to the 3' untranslated region of MORC4. Furthermore, restoration of miR-193b-3p expression in breast cancer cells led to decreased growth and activation of apoptosis, which was consistent with results associated with MORC4 silencing in breast cancer cells. These results identified MORC4 as differentially expressed in breast cancer cells and tissues and its downregulation by miR-193b-3p, as well as its roles in regulating the growth of breast cancer cells via regulation of apoptosis. Our findings offer novel insights into potential mechanisms associated with breast cancer pathogenesis.

lncRNA HOTAIR upregulates COX-2 expression to promote invasion and migration of nasopharyngeal carcinoma by interacting with miR-101

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common type of head and neck cancers which is notable for its distinctive pattern of geographical distribution. HOTAIR has been reported to regulate nasopharyngeal carcinoma tumorigenesis and progression. However, the detailed mechanism underlying HOTAIR-promoted nasopharyngeal carcinoma remains not fully understood.

METHODS

We used RT-qPCR approach to examine genes expression and mRNA level. MTT assay and soft agar assay were used to detect cell growth rate in culture and under suspended condition, respectively. Besides, we employed wound healing assay and transwell invasion assay to determine migration and invasion ability of nasopharyngeal carcinoma cells. We predicted direct downstream targets of miR-101 by bioinformatic analysis, which was confirmed by dual luciferase reporter assay.

RESULTS

HOTAIR was upregulated in NPC tissues and cells. miR-101 inhibitor greatly enhanced HOTAIR knockdown-regulated cell proliferation, migration and invasion of CNE1 and CNE2 cells. miR-101 was shown to directly bind 3'-UTR of COX-2 and downregulate COX-2 expression. Finally, COX-2 overexpression was demonstrated to rescue the tumor phenotypes of nasopharyngeal carcinoma cells attenuated by HOTAIR knockdown or miR-101 mimic.

CONCLUSIONS

Here, we highlight the importance of HOTAIR/miR-101/COX-2 axis in progression of nasopharyngeal carcinoma cells. Our findings provide a novel mechanism for explaining HOTAIR-induced nasopharyngeal carcinoma and help developing the therapeutical strategies by targeting HOTAIR.

Do MicroRNAs Modulate Visceral Pain?

Visceral pain, a common characteristic of multiple diseases relative to viscera, impacts millions of people worldwide. Although hundreds of studies have explored mechanisms underlying visceral pain, it is still poorly managed. Over the past decade, strong evidence emerged suggesting that microRNAs (miRNAs) play a significant role in visceral nociception through altering neurotransmitters, receptors and other genes at the posttranscriptional level. Under pathological conditions, one kind of miRNA may have several target mRNAs and several kinds of miRNAs may act on one target, suggesting complex interactions and mechanisms between miRNAs and target genes lead to pathological states. In this review we report on recent progress in examining miRNAs responsible for visceral sensitization and provide miRNA-based therapeutic targets for the management of visceral pain.

miRNA‑328 overexpression confers cisplatin resistance in non‑small cell lung cancer via targeting of PTEN

Chemotherapy resistance, the molecular mechanism of which is complex and has not been fully understood, poses a major challenge in the treatment of patients with non‑small cell lung cancer (NSCLC). The dysregulation of microRNAs (miRs) has been reported to serve a pivotal role in the development of cancer and drug resistance. In the present study, reverse transcription‑quantitative polymerase chain reaction analysis revealed a significant increase in miR‑328 and a significant decrease in phosphatase and tensin homolog (PTEN) mRNA expression levels within tumor tissues from patients with cisplatin‑resistant NSCLC compared with those of cisplatin‑sensitive NSCLC patients. In addition, there was a negative correlation between PTEN mRNA and the miR‑328 expression levels. In addition, higher miR‑328 expression levels, and lower PTEN mRNA and protein expression levels, were detected in cisplatin‑resistant A549 (A549rCDDP) cells when compared with in their parental cells. A549rCDDP cells demonstrated significantly higher cell viability compared with A549 cells following treatment with all concentrations of cisplatin tested (2, 4, 6 and 8 µM). Additionally, transfection of miR‑328 inhibitor significantly increased PTEN mRNA and protein expression levels. Furthermore, the present study predicted and confirmed PTEN, a well‑known tumor suppressor, as a direct target of miR‑328 in NSCLC cells via the online tool MiRanda and a dual luciferase assay, respectively. Cell viability assay and flow cytometry analysis demonstrated that inhibition of miR‑328 also induced cellular apoptosis and decreased cell proliferation in A549rCDDP cells treated with cisplatin. In conclusion, these results suggested that abnormal expression of miR‑328 may contribute to cisplatin resistance in NSCLC, and may be considered to be a novel therapeutic target and indicator for the treatment and prognosis of patients with NSCLC treated with cisplatin‑based chemotherapy.

miR-106a Reduces 5-Fluorouracil (5-FU) Sensitivity of Colorectal Cancer by Targeting Dual-Specificity Phosphatases 2 (DUSP2)

BACKGROUND 5-Fluorouracil (5-FU)-based chemotherapy is a conventional therapeutic approach for the treatment of patients with colorectal cancer (CRC). However, development of 5-FU resistance frequently occurs. We explored a potential method for regulating the sensitivity to 5-FU-based chemotherapy in CRC patients. MATERIAL AND METHODS Cell viability was determined by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Gene expression levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Protein expression levels were evaluated by Western blot. TargetScan was used for the prediction of binding sites for miRNA in mRNAs. The interaction between mRNA 3'UTR and miRNA was verified by dual luciferase reporter assay. Tissue samples were obtained from 33 CRC patients who received surgery at Xingtai People's Hospital. RESULTS miR-106a level was associated with 5-FU sensitivity in CRC cells. Overexpression of miR-106a reduced 5-FU sensitivity of HCT116 and SW620 cells, and antagonist of miR-106a sensitized HCT116 and SW620 towards 5-FU. miR-106a overexpression decreased dual-specificity phosphatases 2 (DUSP2) expression at mRNA and protein levels in HCT116 and SW620 cells. Through downregulation of DUSP2, miR-106a elevation increased COX-2 expression and stemness-maintenance genes (SOX2 and OCT4). Furthermore, we predicted that miR-106a directly binds to 3'UTR of DUSP2 mRNA, which was confirmed by dual luciferase assay. Silencing of DUSP2 reversed elevated 5-FU sensitivity induced by miR-106a antagonist in HCT116 cells. A negative correlation was discovered between miR-106a and DUSP2 in tumor samples of CRC patients. CONCLUSIONS miR-106a plays an important role in mediating response to 5-FU-based chemotherapy in CRC and could serve as a potential target for CRC patients.

Targeting of G-Quadruplex Harboring Pre-miRNA 92b by LNA Rescues PTEN Expression in NSCL Cancer Cells

Since the elevated levels of microRNAs (miRNAs) often cause various diseases, selective inhibition of miRNA maturation is an important therapeutic strategy. Commonly used anti-miRNA strategies are limited to targeting of mature miRNAs, as the upstream targeting of miRNA maturation with an oligonucleotide is challenging due to the presence of a stable pre-miRNA stem-loop structure. Previously, we reported that about 16% of known human pre-miRNAs have the potential to adopt G-quadruplex (GQ) structures alternatively to canonical stem-loops. Herein, we showed that a rationally designed locked nucleic acid (LNA) binds specifically the GQ conformation of pre-miRNA 92b and inhibits pre-miRNA maturation. Further, we showed that the LNA treatment rescues PTEN expression in non-small-cell lung cancer (NSCLC) cells, which is suppressed by the elevated level of miRNA 92b. Treatment of LNA significantly decreases the IC₅₀ of doxorubicin for NSCLC cells. This strategy can be developed as a novel anti-miRNA therapeutic approach to target GQ harboring miRNAs. This can potentially be a more powerful approach than targeting of the mature miRNA, as it is an upstream targeting and can reduce both 3' and the 5' mature miRNA levels at once.

MicroRNA-101 inhibits angiogenesis via COX-2 in endometrial carcinoma

Abnormal angiogenesis is critically involved in tumor progression and metastasis including endometrial cancer and is regulated by microRNAs such as microRNA-101 (miR-101). We hypothesize that miR-101 expression is disrupted in endometrial cancer and modulation of miR-101 levels is sufficient to regulate tumor growth through angiogenesis. We examined the expression levels of miR-101 and factors involved in angiogenesis in the patients with endometrial cancer. We also overexpressed or inhibited miR-101 in RL-95-2 cells and examined their effects on cell toxicity and tumor growth. Finally, we determined if miR-101 regulated tumorigenesis through cyclooxygenase-2 (COX-2). We found that miR-101 levels were significantly reduced. Factors involved in angiogenesis included vascular endothelial growth factor-A (VEGF-A), thrombospondin-1 (TSP-1), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and aromatase (P450arom), which were increased in endometrial carcinoma. Modulation of miR-101 level was sufficient to affect tumor growth. Finally, we found that the effects of miR-101 inhibition on tumor growth were suppressed by COX-2 inhibition. Our results suggest that modulating miR-101 and COX-2 levels or their activity may be a potential therapeutic strategy for endometrial cancer.

Expression level and potential target pathways of miR-1-3p in colorectal carcinoma based on 645 cases from 9 microarray datasets

For the purpose of demonstrating the clinical value and unraveling the molecular mechanisms of micro RNA (miR)-1-3p in colorectal carcinoma (CRC), the present study collected expression and diagnostic data from Gene Expression Omnibus (GEO), ArrayExpress and existing literature to conduct meta-analyses and diagnostic tests. Furthermore, the potential targets of miR-1-3p were attained from datasets that transfected miR-1-3p into CRC cells, online prediction databases and differentially expressed genes from The Cancer Genome Atlas and literature. Subsequently, bioinformatics analysis was conducted based on the aforementioned selected target genes. As a result, downregulation of miR-1-3p was observed. The combined standardized mean difference was −0.51 with 95% confidence interval (CI) of −0.68 to −0.33 using a fixed effect model, which demonstrated a significant downregulation of miR-1-3p in CRC. The combined sensitivity, specificity, positive likelihood ratio, negative likelihood ratio diagnostic score and odds ratio were 0.74 (95%CI: 0.48, 0.90), 0.75 (95%CI: 0.35, 0.94), 2.94 (95%CI: 1.01, 8.55), 0.34 (95%CI: 0.19, 0.60), 2.15 (95%CI: 1.06, 3.23) and 8.57 (95%CI: 2.89, 25.36). The summarized receiver operating characteristic curve demonstrated that the area under the curve was 0.81. In bioinformatics analyses based on 30 promising targets, the most enriched terms in Gene Ontology were positive regulation of transcription from RNA polymerase II promoter, extracellular region and transcription factor binding. Kyoto Encyclopedia of Genes and Genomes pathway analysis highlighted the pathway termed cytokine-cytokine receptor interaction. In protein-protein interaction analysis, platelet factor 4 was selected as the hub gene. To conclude, miR-1-3p is downregulated in CRC and likely suppresses CRC via multiple biological approaches, which indicates the diagnostic potential and tumor suppressive efficacy.

Transcriptomics Evidence for Common Pathways in Human Major Depressive Disorder and Glioblastoma

Depression as a common complication of brain tumors. Is there a possible common pathogenesis for depression and glioma? The most serious major depressive disorder (MDD) and glioblastoma (GBM) in both diseases are studied, to explore the common pathogenesis between the two diseases. In this article, we first rely on transcriptome data to obtain reliable and useful differentially expressed genes (DEGs) by differential expression analysis. Then, we used the transcriptomics of DEGs to find out and analyze the common pathway of MDD and GBM from three directions. Finally, we determine the important biological pathways that are common to MDD and GBM by statistical knowledge. Our findings provide the first direct transcriptomic evidence that common pathway in two diseases for the common pathogenesis of the human MDD and GBM. Our results provide a new reference methods and values for the study of the pathogenesis of depression and glioblastoma.

MicroRNA-93 Regulates Hypoxia-Induced Autophagy by Targeting ULK1

The expression of the core autophagy kinase, Unc51-like kinase 1 (ULK1), is regulated transcriptionally and translationally by starvation-induced autophagy. However, how ULK1 is regulated during hypoxia is not well understood. Previously, we showed that ULK1 expression is induced by hypoxia stress. Here, we report a new ULK1-modulating microRNA, miR-93; its transcription is negatively correlated with the translation of ULK1 under hypoxic condition. miR-93 targets ULK1 and reduces its protein levels under hypoxia condition. miR-93 also inhibits hypoxia-induced autophagy by preventing LC3-I to LC3-II transition and P62 degradation; these processes are reversed by the overexpression of an endogenous miR-93 inhibitor. Re-expression of ULK1 without miR-93 response elements restores the hypoxia-induced autophagy which is inhibited by miR-93. Finally, we detected the effects of miR-93 on cell viability and apoptosis in noncancer cell lines and cancer cells. We found that miR-93 sustains the viability of MEFs (mouse embryonic fibroblasts) and inhibits its apoptosis under hypoxia. Thus, we conclude that miR-93 is involved in hypoxia-induced autophagy by regulating ULK1. Our results provide a new angle to understand the complicated regulation of the key autophagy kinase ULK1 during different stress conditions.

Differential expression of small RNA pathway genes associated with the Biomphalaria glabrata/Schistosoma mansoni interaction

The World Health Organization (WHO) estimates that approximately 240 million people in 78 countries require treatment for schistosomiasis, an endemic disease caused by trematodes of the genus Schistosoma. In Brazil, Schistosoma mansoni is the only species representative of the genus whose passage through an invertebrate host, snails of the genus Biomphalaria, is obligatory before infecting a mammalian host, including humans. The availability of the genome and transcriptome of B. glabrata makes studying the regulation of gene expression, particularly the regulation of miRNA and piRNA processing pathway genes, possible. This might assist in better understanding the biology of B. glabrata as well as its relationship to the parasite S. mansoni. Some aspects of this interaction are still poorly explored, including the participation of non-coding small RNAs, such as miRNAs and piRNAs, with lengths varying from 18 to 30 nucleotides in mature form, which are potent regulators of gene expression. Using bioinformatics tools and quantitative PCR, we characterized and validated the miRNA and piRNA processing pathway genes in B. glabrata. In silico analyses showed that genes involved in miRNA and piRNA pathways were highly conserved in protein domain distribution, catalytic site residue conservation and phylogenetic analysis. Our study showed differential expression of putative Argonaute, Drosha, Piwi, Exportin-5 and Tudor genes at different snail developmental stages and during infection with S. mansoni, suggesting that the machinery is required for miRNA and piRNA processing in B. glabrata at all stages. These data suggested that the silencing pathway mediated by miRNAs and piRNAs can interfere in snail biology throughout the life cycle of the snail, thereby influencing the B. glabrata/S. mansoni interaction. Further studies are needed to confirm the participation of the small RNA processing pathway proteins in the parasite/host relationship, mainly the effective participation of small RNAs in regulating their target genes.

Impact of microRNA dynamics on cancer hallmarks: An oral cancer scenario

MicroRNAs are endogenous small noncoding RNAs that negatively regulate gene expression at posttranscriptional level. The discovery of microRNAs has identified a new layer of gene regulation mechanisms, which play a pivotal role in development as well as in various cellular processes, such as proliferation, differentiation, cell growth, and cell death. Deregulated microRNA expression favors acquisition of cancer hallmark traits as well as transforms the tumor microenvironment, leading to tumor development and progression. Many recent studies have revealed altered expression of microRNAs in oral carcinoma with several microRNAs shown to have key biological role in tumorigenesis functioning either as tumor suppressors or as tumor promoters. MicroRNA expression levels correlate with clinicopathological variables and have a diagnostic and prognostic value in oral carcinoma. For these reasons, microRNA has been a hot topic in oral cancer research for the last few years. In this review, we attempt to summarize the present understanding of microRNA deregulation in oral carcinoma, their role in acquiring cancer hallmarks, and their potential diagnostic and prognostic value for oral cancer management.

Identification of microRNA signature and potential pathway targets in prostate cancer

Prostate cancer (PC) is the most common and the second leading cause of cancer-related death among American men. Early diagnosis is a prerequisite to improving therapeutic benefits. However, the current clinical biomarkers for PC do not reliably decipher indolent PC from other urogenital disorders. Thus, effective clinical intervention necessitates development of new biomarkers for early detection of PC. The present study aimed to identify the miRNA signature in organ-confined (Gleason Score 6) prostate tumors. MicroRNA (miRNA/miR) array analysis identified 118 upregulated and 73 downregulated miRNAs in microdissected tumors in comparison to matched neighboring normal prostate epithelium. The miRs-Plus-A1083, -92b-5p, -18a-3p, -19a-3p, -639, -3622b-3p, -3189-3p, -155-3p, -410, -1179, 548b-5p, and -4469 are predominantly expressed (7-11-fold), whereas miRs-595, 4490, -3120-5p, -1299, -21-5p, -3677-3, -let-7b-5p, -5189, 3-121-5p, -4518, -200a-5p, -3682-5p, -3689d, -3149 represent the most downregulated (12-113-fold) miRNAs in microdissected prostate tumors. The array expression profile of selected miRNA signature and their potential mRNA targets was validated by qRT-PCR analysis in PC cell lines. Integrated in silico and computational prediction analyses demonstrated that the dysregulated miRNA signature map to key regulatory factors involved in tumorigenesis, including cell cycle, apoptosis, and p53 pathways. The newly identified miRNA signature has potential clinical utility as biomarkers, prognostic indicators, and therapeutic targets for early detection of PC. Further studies are needed to assess the functional significance and clinical usefulness of the identified miRNAs. Impact Statement To our knowledge his is the first study of identifying miRNA signatures in microdissected indolent (Gleason score 6) prostate cancer in comparison to matched normal prostate epithelium. By employing in silico and computational prediction analysis, the study provides a landscape of potential miRNA targets and key cellular pathways involved in prostate tumorigenesis. Identification if miRNAs and their relevant targets and pathways pave the way for underpinning their mechanistic role of miRNAs in human prostate tumorigenesis, and possibly other human cancers. Importantly, the outcome of the study has important clinical implications for the management of prostate cancer, including the use of miRNA(s) as biomarkers for early detection of prostate cancer.

Site-Specific Labeling of MicroRNA Precursors: A Structure-Activity Relationship Study

Functionalized oligoribonucleotides are essential tools in RNA chemical biology. Various synthetic routes have been developed over recent years to conjugate functional groups to oligoribonucleotides. However, the presence of the functional group on the oligoribonucleotide backbone can lead to partial or total loss of biological function. The limited knowledge concerning the positioning of functional groups therefore represents a hurdle for the development of oligoribonucleotide chemical tools. Here we describe a systematic investigation of site-specific labeling of pre-miRNAs to identify positions for the incorporation of functional groups, in order not to hinder their processing into active mature miRNAs.

Towards a molecular understanding of microRNA-mediated gene silencing

MicroRNAs (miRNAs) are a conserved class of small non-coding RNAs that assemble with Argonaute proteins into miRNA-induced silencing complexes (miRISCs) to direct post-transcriptional silencing of complementary mRNA targets. Silencing is accomplished through a combination of translational repression and mRNA destabilization, with the latter contributing to most of the steady-state repression in animal cell cultures. Degradation of the mRNA target is initiated by deadenylation, which is followed by decapping and 5'-to-3' exonucleolytic decay. Recent work has enhanced our understanding of the mechanisms of silencing, making it possible to describe in molecular terms a continuum of direct interactions from miRNA target recognition to mRNA deadenylation, decapping and 5'-to-3' degradation. Furthermore, an intricate interplay between translational repression and mRNA degradation is emerging.

Point-of-care diagnostic tools to detect circulating microRNAS as biomarkers of disease

MicroRNAs or miRNAs are a form of small non-coding RNAs (ncRNAs) of 19–22 nucleotides in length in their mature form. miRNAs are transcribed in the nucleus of all cells from large precursors, many of which have several kilobases in length. Originally identified as intracellular modulators of protein synthesis via posttranscriptional gene silencing, more recently it has been found that miRNAs can travel in extracellular human fluids inside specialized vesicles known as exosomes. We will be referring to this miRNAs as circulating microRNAs. More interestingly, the miRNA content inside exosomes changes during pathological events. In the present review we analyze the literature about circulating miRNAs and their possible use as biomarkers. Furthermore, we explore their future in point-of-care (POC) diagnostics and provide an example of a portable POC apparatus useful in the detection of circulating miRNAs.