miRNA biogenesis: biological impact in the development of cancer

Therapeutic potential of SMAD7 targeting miRNA in the pathogenesis of diabetic nephropathy

Diabetic nephropathy (DN) is a common complication of diabetes and a leading cause of end-stage renal disease, characterized by progressive kidney fibrosis and inflammation. The transforming growth factor-beta (TGF-β) signaling pathway plays a crucial role in the pathogenesis of diabetes nephropathy, and SMAD7 is a key negative regulator of this pathway. Recent studies have highlighted the involvement of miRNA in the progression of DN. Computational analysis identified 11 potential miRNAs such as miR-424, miR-195, miR-216a, miR-503, miR-15a-5p, miR-15b-5p, miR-665, miR-520h, miR16-5p, miR-21 and miR-32-5p which are predicted to target 3'UTR of SMAD7 mRNA. This review aims to explore the role of these miRNAs in the progression of DN. Notably, these miRNAs have shown therapeutic potential in mitigating fibrosis and inflammation by modulating SMAD7 expression in DN. Future directions can be to investigate the mechanistic pathways through which these miRNAs exert their effects, as well as optimizing delivery systems for effective clinical application. Targeting miRNAs that modulate SMAD7 expression represents a promising strategy for developing specific and effective therapies for diabetic nephropathy.

MicroRNAs as behind-the-scenes molecules in breast cancer metastasis and their therapeutic role through novel microRNA-based delivery strategies

Breast cancer is the primary cause of cancer-related death and the most frequent malignancy among women in Western countries. Although there have been advancements in combination treatments and targeted therapies for the metastatic diseases management, metastatic breast cancer is still the second most common cause of cancer-related deaths among U.S. women. The routes of metastasis encompass invasion, intravasation, circulation, extravasation, infiltration into a remote location to establish a metastatic niche, and the formation of micro-metastases in a new environment. Each of these processes is regulated by changes in gene expression. MicroRNAs (miRNAs) are widely expressed by a variety of organisms and have a key role in cell activities including suppressing or promoting cancer through regulating various pathways. Target gene expression is post-transcriptionally regulated by miRNAs, which contribute to the development, spread, and metastasis of breast cancer. In this study, we comprehensively discussed the role of miRNAs as predictors of breast cancer metastasis, their correlation with the spread of the disease to certain organs, and their potential application as targets for breast cancer treatment. We also provided molecular mechanisms of miRNAs in the progression of breast cancer, as well as current challenges in miRNA-based therapeutic approaches. Furthermore, as one of the primary issues with the treatment of solid malignancies is the efficient delivery of miRNAs, we examined a number of cutting-edge carriers for miRNA-based therapies and CRISPR/Cas9 as a targeted therapy for breast cancer.

MiRNAs function in the development of resistance against doxorubicin in cancer cells: targeting ABC transporters

Resistance to chemotherapeutic agents poses a significant challenge in cancer treatment, particularly with doxorubicin, a widely used drug for various cancers, including breast cancer, leukaemia, osteosarcoma, and gastrointestinal cancers. This review aims to elucidate the critical role of microRNAs (miRNAs) in the development of doxorubicin resistance, focusing on their interactions with ATP-binding cassette (ABC) transporters. Despite extensive research, the molecular mechanisms governing doxorubicin resistance still need to be completed, particularly regarding the regulatory influence of miRNAs on ABC transporter expression. By analyzing current literature, this review identifies a notable gap: the lack of comprehensive insight into how specific miRNAs modulate the expression and activity of ABC transporters in cancer cells, contributing to doxorubicin resistance. We systematically examine recent findings on the interplay between miRNAs and ABC transporters, providing a detailed assessment of potential therapeutic strategies that leverage miRNA modulation to overcome drug resistance. Ultimately, this review underscores the significance of integrating miRNA research into existing therapeutic frameworks to enhance the efficacy of doxorubicin in cancer treatment.

MicroRNA in prostate cancer: from biogenesis to applicative potential

Prostate cancer is the most common solid malignant tumor in men, characterized by high morbidity and mortality. While current screening tools, such as prostate-specific antigen (PSA) testing and digital rectal examination, are available for early detection of prostate cancer, their sensitivity and specificity are limited. Tissue puncture biopsy, although capable of offering a definitive diagnosis, has poor positive predictive rates and burdens the patient more. Therefore, more reliable molecular diagnostic tools for prostate cancer urgently need to be developed. In recent years, microRNAs (miRNAs) have attracted much attention in prostate cancer research. miRNAs are extensively engaged in biological processes such as cell proliferation, differentiation, apoptosis, migration, and invasion by modulating gene expression post-transcriptionally. Dysregulation of miRNA expression in cancer is considered a critical factor in tumorigenesis and progression. This review first briefly introduces the biogenesis of miRNAs and their functions in cancer, then focuses on tumor-promoting miRNAs and tumor-suppressor miRNAs in prostate cancer. Finally, the potential application of miRNAs as multifunctional tools for cancer diagnosis, prognostic assessment, and therapy is discussed in detail. The concluding section summarizes the major points of the review and the challenges ahead.

RNA-Binding Proteins as Novel Effectors in Osteoblasts and Osteoclasts: A Systems Biology Approach to Dissect the Transcriptional Landscape

Bone health is ensured by the coordinated action of two types of cells-the osteoblasts that build up bone structure and the osteoclasts that resorb the bone. The loss of balance in their action results in pathological conditions such as osteoporosis. Central to this study is a class of RNA-binding proteins (RBPs) that regulates the biogenesis of miRNAs. In turn, miRNAs represent a critical level of regulation of gene expression and thus control multiple cellular and biological processes. The impact of miRNAs on the pathobiology of various multifactorial diseases, including osteoporosis, has been demonstrated. However, the role of RBPs in bone remodeling is yet to be elucidated. The aim of this study is to dissect the transcriptional landscape of genes encoding the compendium of 180 RBPs in bone cells. We developed and applied a multi-modular integrative analysis algorithm. The core methodology is gene expression analysis using the GENEVESTIGATOR platform, which is a database and analysis tool for manually curated and publicly available transcriptomic data sets, and gene network reconstruction using the Ingenuity Pathway Analysis platform. In this work, comparative insights into gene expression patterns of RBPs in osteoblasts and osteoclasts were obtained, resulting in the identification of 24 differentially expressed genes. Furthermore, the regulation patterns upon different treatment conditions revealed 20 genes as being significantly up- or down-regulated. Next, novel gene-gene associations were dissected and gene networks were reconstructed. Additively, a set of osteoblast- and osteoclast-specific gene signatures were identified. The consolidation of data and information gained from each individual analytical module allowed nominating novel promising candidate genes encoding RBPs in osteoblasts and osteoclasts and will significantly enhance the understanding of potential regulatory mechanisms directing intracellular processes in the course of (patho)physiological bone turnover.

MicroRNA Expression Profile in Patients Admitted to ICU as Novel and Reliable Approach for Diagnostic and Therapeutic Purposes

The ability to detect early metabolic changes in patients who have an increased mortality risk in the intensive care units (ICUs) could increase the likelihood of predicting recovery patterns and assist in disease management. Markers that can predict the disease progression of patients in the ICU might also be beneficial for improving their medical profile. Although biomarkers have been used in the ICU more frequently in recent years, the clinical use of most of them is limited. A wide range of biological processes are influenced by microRNAs (miRNAs) that modulate the translation and stability of specific mRNAs. Studies suggest that miRNAs may serve as a diagnostic and therapeutic biomarker in ICUs by profiling miRNA dysregulation in patient samples. To improve the predictive value of biomarkers for ICU patients, researchers have proposed both investigating miRNAs as novel biomarkers and combining them with other clinical biomarkers. Herein, we discuss recent approaches to the diagnosis and prognosis of patients admitted to an ICU, highlighting the use of miRNAs as novel and robust biomarkers for this purpose. In addition, we discuss emerging approaches to biomarker development and ways to improve the quality of biomarkers so that patients in ICU get the best outcomes possible.

MicroRNA-194 regulates parasitic load and IL-1β-dependent nitric oxide production in the peripheral blood mononuclear cells of dogs with leishmaniasis

Domestic dogs are the primary urban reservoirs of Leishmania infantum, the causative agent of visceral leishmaniasis. In Canine Leishmaniasis (CanL), modulation of the host's immune response may be associated with the expression of small non-coding RNAs called microRNA (miR). miR-194 expression increases in peripheral blood mononuclear cells (PBMCs) of dogs with leishmaniasis with a positive correlation with the parasite load and in silico analysis demonstrated that the TRAF6 gene is the target of miR-194 in PBMCs from diseased dogs. Here, we isolated PBMCs from 5 healthy dogs and 28 dogs with leishmaniasis, naturally infected with L. infantum. To confirm changes in miR-194 and TRAF6 expression, basal expression of miR-194 and gene expression of TRAF6 was measured using qPCR. PBMCs from healthy dogs and dogs with leishmaniasis were transfected with miR-194 scramble, mimic, and inhibitor and cultured at 37° C, 5% CO2 for 48 hours. The expression of possible targets was measured: iNOS, NO, T-bet, GATA3, and FoxP3 were measured using flow cytometry; the production of cytokines IL-1β, IL-4, IL-6, IL-10, TNF-α, IFN-γ, and TGF-β in cell culture supernatants was measured using capture enzyme-linked immunosorbent assays (ELISA). Parasite load was measured using cytometry and qPCR. Functional assays followed by miR-194 inhibitor and IL-1β blockade and assessment of NO production were also performed. Basal miR-194 expression was increased in PBMC from dogs with Leishmaniasis and was negatively correlated with TRAF6 expression. The mimic of miR-194 promoted an increase in parasite load. There were no significant changes in T-bet, GATA3, or FoxP3 expression with miR-194 enhancement or inhibition. Inhibition of miR-194 increased IL-1β and NO in PBMCs from diseased dogs, and blockade of IL-1β following miR-194 inhibition decreased NO levels. These findings suggest that miR-194 is upregulated in PBMCs from dogs with leishmaniasis and increases parasite load, possibly decreasing NO production via IL-1β. These results increase our understanding of the mechanisms of evasion of the immune response by the parasite and the identification of possible therapeutic targets.

LncRNA RUNX1-IT1 is downregulated in gastric cancer and suppresses the maturation of miR-20a by binding to its precursor

BACKGROUND

RUNX1-IT1 has been characterized as a tumor suppressive long non-coding RNA (lncRNA) in several types of cancer but not gastric cancer (GC). This study aimed to explore the role of RUNX1-IT1 in GC.

METHODS

The expression of RUNX1-IT1, microRNA (miR)-20a precursor and mature miR-20a in GC and healthy tissues donated by GC patients (n=62) were measured by RT-qPCR. Correlation analysis was performed by linear regression. The expression of mature miR-20a and miR-20a precursor in cells with overexpression of RUNX1-IT1 was also determined by RT-qPCR. Cell invasion and migration were evaluated by Transwell assays.

RESULTS

RUNX1-IT1 was downregulated in GC. Across GC tissues, RUNX1-IT1 and mature miR-20a were inversely correlated. However, RUNX1-IT1 and miR-20a precursor were not closely correlated. RUNX1-IT1 and miR-20a precursor were predicted to interact with each other, and overexpression of RUNX1-IT1 in GC cells decreased the expression levels of mature miR-20a. Transwell assay showed that the enhancing effect of miR-20a on cell invasion and migration was reduced by overexpression of RUNX1-IT1.

CONCLUSIONS

RUNX1-IT1 may suppress the GC cell movement by inhibiting the maturation of miR-20a.

The roles of different microRNAs in the regulation of cholesterol in viral hepatitis

Cholesterol plays a significant role in stabilizing lipid or membrane rafts, which are specific cellular membrane structures. Cholesterol is involved in numerous cellular processes, including regulating virus entry into the host cell. Multiple viruses have been shown to rely on cholesterol for virus entry and/or morphogenesis. Research indicates that reprogramming of the host's lipid metabolism is associated with hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in the progression to severe liver disease for viruses that cause chronic hepatitis. Moreover, knowing the precise mode of viral interaction with target cells sheds light on viral pathogenesis and aids in the development of vaccines and therapeutic targets. As a result, the area of cholesterol-lowering therapy is quickly evolving and has many novel antiviral targets and medications. It has been shown that microRNAs (miRNAs) either directly or indirectly target the viral genome, preventing viral replication. Moreover, miRNAs have recently been shown to be strong post-transcriptional regulators of the genes involved in lipid metabolism, particularly those involved in cholesterol homeostasis. As important regulators of lipid homeostasis in several viral infections, miRNAs have recently come to light. In addition, multiple studies demonstrated that during viral infection, miRNAs modulate several enzymes in the mevalonate/cholesterol pathway. As cholesterol metabolism is essential to the life cycle of viral hepatitis and other viruses, a sophisticated understanding of miRNA regulation may contribute to the development of a novel anti-HCV treatment. The mechanisms underlying the effectiveness of miRNAs as cholesterol regulators against viral hepatitis are explored in this review. Video Abstract.

The dysregulation of miRNAs in epilepsy and their regulatory role in inflammation and apoptosis

Epilepsy is a neurological disorder that impacts millions of people worldwide, and it is characterized by the occurrence of recurrent seizures. The pathogenesis of epilepsy is complex, involving dysregulation of various genes and signaling pathways. MicroRNAs (miRNAs) are a group of small non-coding RNAs that play a vital role in the regulation of gene expression. They have been found to be involved in the pathogenesis of epilepsy, acting as key regulators of neuronal excitability and synaptic plasticity. In recent years, there has been a growing interest in exploring the miRNA regulatory network in epilepsy. This review summarizes the current knowledge of the regulatory miRNAs involved in inflammation and apoptosis in epilepsy and discusses its potential as a new avenue for developing targeted therapies for the treatment of epilepsy.

MicroRNA‑153 may act as a potential biomarker and prognostic indicator of patients with gastric cancer

MicroRNA (miR/miRNA)-153, as a novel tumor-related miRNA, has been found to be aberrantly expressed in different types of cancer; however, to the best of our knowledge, the role of miR-153 in gastric cancer (GC) remains unclear. The present study demonstrated that miR-153 expression was markedly decreased in GC, including GC cell lines and culture medium, GC tissues, and serum samples, based on reverse transcription-quantitative PCR, and this was further confirmed by fluorescence in situ hybridization. Transfection with miR-153 mimics inhibited proliferation and migration, and promoted apoptosis in GC cells. The serum expression levels of miR-153 were decreased in 59 patients with GC compared with those of 9 healthy controls, and more decreased in advanced GC compared with early-stage GC, suggesting that miR-153 was associated with tumor progression. Furthermore, serum miR-153 was expressed at significantly lower levels in patients with GC with larger tumor size (≥4 cm; P=0.013), poor differentiation and signet histology (P=0.013), lymph node metastasis (P=0.025) and advanced tumor stage (TNM stage III and IV; P=0.048) compared with patients with a smaller tumor size (<4 cm), well and moderate differentiation, no lymph node metastasis, and TNM stage I and II, respectively. In conclusion, the present study revealed that low miR-153 expression was associated with poor prognosis in GC and miR-153 may potentially act as a tumor biomarker and therapeutic target in GC.

Regulation of the Cell Cycle by ncRNAs Affects the Efficiency of CDK4/6 Inhibition

Cyclin-dependent kinases (CDKs) regulate cell division at multiple levels. Aberrant proliferation induced by abnormal cell cycle is a hallmark of cancer. Over the past few decades, several drugs that inhibit CDK activity have been created to stop the development of cancer cells. The third generation of selective CDK4/6 inhibition has proceeded into clinical trials for a range of cancers and is quickly becoming the backbone of contemporary cancer therapy. Non-coding RNAs, or ncRNAs, do not encode proteins. Many studies have demonstrated the involvement of ncRNAs in the regulation of the cell cycle and their abnormal expression in cancer. By interacting with important cell cycle regulators, preclinical studies have demonstrated that ncRNAs may decrease or increase the treatment outcome of CDK4/6 inhibition. As a result, cell cycle-associated ncRNAs may act as predictors of CDK4/6 inhibition efficacy and perhaps present novel candidates for tumor therapy and diagnosis.

miRNAs as potential game-changers in melanoma: A comprehensive review

Melanoma is the sixth most frequent malignancy. It represents 1.7% of all cancer cases worldwide. Many risk factors are associated with melanoma including ultraviolet radiation skin phenotype, Pigmented Nevi, Pesticides, and genetic and epigenetic factors. Of the main epigenetic factors affecting melanoma are microribonucleic acids (miRNAs). They are short nucleic acid chains that have the potential to prevent the expression of a number of target genes. They could target a number of genes related to melanoma initiation, stemness, angiogenesis, apoptosis, proliferation, and potential resistance to treatment. Additionally, they can control several melanoma signaling pathways, including P53, WNT/-catenin, JAK/STAT, PI3K/AKT/mTOR axis, TGF- β, and EGFR. MiRNAs also play a role in the resistance of melanoma to essential treatment regimens. The stability and abundance of miRNAs might be important factors enhancing the use of miRNAs as markers of prognosis, diagnosis, stemness, survival, and metastasis in melanoma patients.

Arsenic resistance protein 2 and microRNA biogenesis: Biological implications in cancer development

Arsenic resistance protein 2 (Ars2) is a nuclear protein that plays a critical role in the regulation of microRNA (miRNA) biogenesis. Ars2 is required for cell proliferation and for the early stages of mammalian development through a possible effect on miRNA processing. Increasing evidence reveal that Ars2 is highly expressed in proliferating cancer cells, suggesting that Ars2 may be a potential therapeutic target for cancer. Therefore, development of the novel Ars2 inhibitors could represent the novel therapeutic strategies for treatment of cancer. In this review, we briefly discuss the mechanisms by which Ars2 regulates miRNA biogenesis and its impact on cell proliferation and cancer development. Particularly, we mainly discuss the role of Ars2 in the regulation of cancer development and highlight pharmacological targeting of Ars2 as a promising cancer therapeutic strategy.

The potential use of mesenchymal stem cells-derived exosomes as microRNAs delivery systems in different diseases

MicroRNAs (miRNAs) are a group of small non-coding RNAs that regulate gene expression by targeting mRNA. Moreover, it has been shown that miRNAs expression are changed in various diseases, such as cancers, autoimmune disease, infectious diseases, and neurodegenerative Diseases. The suppression of miRNA function can be easily attained by utilizing of anti-miRNAs. In contrast, an enhancement in miRNA function can be achieved through the utilization of modified miRNA mimetics. The discovery of appropriate miRNA carriers in the body has become an interesting subject for investigators. Exosomes (EXOs) therapeutic efficiency and safety for transferring different cellular biological components to the recipient cell have attracted significant attention for their capability as miRNA carriers. Mesenchymal stem cells (MSCs) are recognized to generate a wide range of EXOs (MSC-EXOs), showing that MSCs may be effective for EXO generation in a clinically appropriate measure as compared to other cell origins. MSC-EXOs have been widely investigated because of their immune attributes, tumor-homing attributes, and flexible characteristics. In this article, we summarized the features of miRNAs and MSC-EXOs, including production, purification, and miRNA loading methods of MSC-EXOs, and the modification of MSC-EXOs for targeted miRNA delivery in various diseases. Video abstract.

Long non-coding RNA SENCR alleviates endothelial-to-mesenchymal transition via targeting miR-126a

INTRODUCTION

Long non-coding RNAs (lncRNAs) constitute a growing class of non-coding genes with diverse cellular function. Recent studies have reported that lncRNA smooth muscle and endothelial cell-enriched (SENCR) was associated with the phenotype switch of vascular smooth muscle cells and participated in vascular homeostasis. However, the potential role of SENCR in endothelial-to-mesenchymal transition (EndMT) and the underlying mechanism remain unknown.

MATERIAL AND METHODS

Human carotid plaque samples and human coronary endothelial cells (HACECs) were collected to examine the expression of SENCR. Quantitative PCR and immunoblots were performed to evaluate the expression of SENCR and miR-126a in HACECs in response to TGF-β1 and transfected with small interfering RNA.

RESULTS

We found that SENCR was significantly decreased in carotid plaques as compared to normal carotids. Knockdown of SENCR in HACECs aggravated the expression of smooth muscle markers α-SMA and calponin induced by TGF-β1 but repressed the expression of endothelial markers platelet/endothelial cell adhesion molecule 1 (PECAM1) and VE-cadherin down-regulated by TGF-β1. Through bioinformatic analysis and Luciferase assay, miR-126a was identified as the direct target of SENCR. Further mechanistic experiments revealed that overexpression of miR-126a bound to the 3'UTR region of SMURF2 and inhibited the expression of SMURF2, which was considered as the negative regulator of TGF-β/Smad signaling. Finally, overexpression of miR-126a did not restore the decreased expression of the smooth muscle markers α-SMA and calponin under the condition of SMURF2 depletion, suggesting that the effect of miR-126a on EndMT progression is SMURF2 dependent.

CONCLUSIONS

SENCR alleviates TGF-β-induced EndMT and sponges miR-126a expression via direct inhibition of the negative regulator of TGF-β/Smad signaling SMURF2.

MicroRNAs as a Novel Player for Differentiation of Mesenchymal Stem Cells into Cardiomyocytes

Cardiovascular disease (CVD) is defined as a class of disorders affecting the heart and blood vessels. Cardiomyocytes and endothelial cells play important roles in cardiac regeneration and heart repair. However, the proliferating capacity of cardiomyocytes is limited. To overcome this issue, mesenchymal stem cells (MSCs) have emerged as an alternative strategy for CVD therapy. MSCs can proliferate and differentiate (or trans-differentiate) into cardiomyocytes. Several in vitro and in vivo differentiation protocols have been used to obtain MSCs-derived cardiomyocytes. It was recently investigated that microRNAs (miRNAs) by targeting several signaling pathways, including STAT3, Wnt/β-catenin, Notch, and TBX5, play a crucial role in regulating cardiomyocytes' differentiation of MSCs. In this review, we focused on the role of miRNAs in the differentiation of MSCs into cardiomyocytes.

Association of DROSHA rs6877842, rs642321 and rs10719 polymorphisms with increased susceptibility to breast cancer: A case-control study with genotype and haplotype analysis

BACKGROUND

Multiple lines of evidence suggest that single nucleotide polymorphisms (SNPs) in genes encoding components of the microRNA processing machinery may underlie susceptibility to various human diseases, including cancer.

OBJECTIVE

The present study aimed to investigate whether rs6877842, rs642321 and rs10719 SNPs of DROSHA, a key component of the miRNA biogenesis pathway, are associated with increased risk of breast cancer.

METHODS

A total of 100 patients diagnosed with breast cancer and 100 healthy women were included. Following extraction of DNA, genotyping was performed by tetra primer- amplification refractory mutation system-PCR (T-ARMS-PCR) technique. Under the co-dominant, dominant and recessive inheritance models, the association between DROSHA SNPs and breast cancer risk was determined by logistic regression analysis. The association of DROSHA SNPs with patients' clinicopathological parameters was assessed. Also, haplotype analysis was performed to evaluate the combined effect of DROSHA SNPs on breast cancer risk.

RESULTS

We observed a statistically significant association between DROSHA rs642321 polymorphism and breast cancer susceptibility (P < 0.05). Under the dominant inheritance model, DROSHA rs642321 polymorphism was significantly associated with increased risk of breast cancer (OR: 6.091; 95% CI: 3.291-11.26; P = 0.0001). Our findings demonstrated that DROSHA rs642321 T allele can contribute to the development of breast cancer (OR: 3.125; 95% CI: 1.984-4.923; P = 0.0001). We also found that GTC and GTT haplotypes conferred significant risk for breast cancer (OR: 2.367; 95% CI: 1.453-3.856; P = 0.0001 and OR: 7.944; 95% CI: 2.073-30.43; P = 0.0001, respectively).

CONCLUSIONS

These results provide the first evidence that DROSHA rs642321 polymorphism is associated with increased risk of breast cancer. However, further studies are needed to firmly validate these findings.

Inhibitory Effects of Ursolic Acid on the Stemness and Progression of Human Breast Cancer Cells by Modulating Argonaute-2

The stemness and metastasis of cancer cells are crucial features in determining cancer progression. Argonaute-2 (AGO2) overexpression was reported to be associated with microRNA (miRNA) biogenesis, supporting the self-renewal and differentiation characteristics of cancer stem cells (CSCs). Ursolic acid (UA), a triterpene compound, has multiple biological functions, including anticancer activity. In this study, we find that UA inhibits the proliferation of MDA-MB-231 and MCF-7 breast cancer cell lines using the CCK-8 assay. UA induced a significant decrease in the fraction of CSC in which it was examined by changes in the expression of stemness biomarkers, including the Nanog and Oct4 genes. UA altered invasion and migration capacities by significant decreases in the levels of epithelial-to-mesenchymal transition (EMT) proteins of slug and vimentin. Furthermore, the co-reduction in oncogenic miRNA levels (miR-9 and miR-221) was a result of the down-modulation in AGO2 in breast cancer cells in vitro. Mechanically, UA increases PTEN expression to inactivate the FAK/PI3K/Akt/mTOR signaling pathway and the decreased level of c-Myc in quantitative RT-PCR and Western blot imaging analyses. Our current understanding of the anticancer potential of UA in interrupting between EMT programming and the state of CSC suggests that UA can contribute to improvements in the clinical practice of breast cancer.

A domino-like localized cascade toehold assembly amplification-based DNA nanowire for microRNA imaging in living cells

High sensitivity and specificity imaging of miRNA in living cells plays an important role in understanding miRNA-related regulation and pathological research. Localized DNA circuits have shown good performance in reaction rate and sensitivity and have been proposed for sensitive imaging of miRNA in living cells. However, most reported localized DNA circuits have a high risk of derailment or a limited loading rate capacity, which hinder their further application. To solve these issues, we herein developed a domino-like localized cascade toehold assembly (LCTA) amplification-based DNA nanowire to achieve highly sensitive and highly specific imaging of miRNAs in living cells by using DNA nanowires as reactant delivery vehicles and confining both reactant probes in a compact space. The LCTA is constructed by interval hybridization of DNA double-stranded probe pairs to a DNA nanowire with multiplex footholds generated by alternating chain hybridization. Due to the localized effect, the LCTA showed high reaction kinetics and sensitivity, and the method could detect miRNAs as low as 51 pM. The LCTA was proven to be able to accurately distinguish the miRNA expression difference between normal cells and cancer cells. In particular, the developed LCTA could be used to construct an OR logic gate to simultaneously image the total amount of multiple miRNAs in living cells. We believe that the developed LCTA can be an effective intracellular nucleic acid imaging tool and can promote the development of nucleic acid-related clinical disease diagnosis and DNA logical sensors.

Therapeutic potential of targeting mirnas to prostate cancer tumors: using psma as an active target

Prostate cancer (PC) is a commonly diagnosed malignancy in men and is associated with high mortality rates. Current treatments for PC include surgery, chemotherapy, and radiation therapy. However, recent advances in targeted delivery systems have yielded promising new approaches to PC treatment. As PC epithelial cells express high levels of prostate-specific membrane antigen (PSMA) on the cell surface, new drug conjugates focused on PSMA targeting have been developed. microRNAs (miRNAs) are small noncoding RNAs that regulate posttranscriptional gene expression in cells and show excellent possibilities for use in developing new therapeutics for PC. PSMA-targeted therapies based on a miRNA payload and that selectively target PC cells enhances therapeutic efficacy without eliciting damage to normal surrounding tissue. This review discusses the rationale for utilizing miRNAs to target PSMA, revealing their potential in therapeutic approaches to PC treatment. Different delivery systems for miRNAs and challenges to miRNA therapy are also explored.

Inferring microRNA regulation: A proteome perspective

Post-transcriptional regulation in multicellular organisms is mediated by microRNAs. However, the principles that determine if a gene is regulated by miRNAs are poorly understood. Previous works focused mostly on miRNA seed matches and other features of the 3′-UTR of transcripts. These common approaches rely on knowledge of the miRNA families, and computational approaches still yield poor, inconsistent results, with many false positives. In this work, we present a different paradigm for predicting miRNA-regulated genes based on the encoded proteins. In a novel, automated machine learning framework, we use sequence as well as diverse functional annotations to train models on multiple organisms using experimentally validated data. We present insights from tens of millions of features extracted and ranked from different modalities. We show high predictive performance per organism and in generalization across species. We provide a list of novel predictions including Danio rerio (zebrafish) and Arabidopsis thaliana (mouse-ear cress). We compare genomic models and observe that our protein model outperforms, whereas a unified model improves on both. While most membranous and disease related proteins are regulated by miRNAs, the G-protein coupled receptor (GPCR) family is an exception, being mostly unregulated by miRNAs. We further show that the evolutionary conservation among paralogs does not imply any coherence in miRNA regulation. We conclude that duplicated paralogous genes that often changed their function, also diverse in their tendency to be miRNA regulated. We conclude that protein function is informative across species in predicting post-transcriptional miRNA regulation in living cells.

MicroRNA Processing Pathway-Based Polygenic Score for Clear Cell Renal Cell Carcinoma in the Volga-Ural Region Populations of Eurasian Continent

The polygenic scores (PGSs) are developed to help clinicians in distinguishing individuals at high risk of developing disease outcomes from the general population. Clear cell renal cell carcinoma (ccRCC) is a complex disorder that involves numerous biological pathways, one of the most important of which is responsible for the microRNA biogenesis machinery. Here, we defined the biological-pathway-specific PGS in a case-control study of ccRCC in the Volga-Ural region of the Eurasia continent. We evaluated 28 DNA SNP variants, located in microRNA biogenesis genes, in 464 individuals with clinically diagnosed ccRCC and 1042 individuals without the disease. Individual genetic risks were defined using the SNP-variant effects derived from the ccRCC association analysis. The final weighted and unweighted PGS models were based on 21 SNPs, and 7 SNPs were excluded due to high LD. In our dataset, microRNA-machinery-weighted PGS revealed 1.69-fold higher odds (95% CI [1.51–1.91]) for ccRCC risk in individuals with ccRCC compared with controls with a p-value of 2.0 × 10−16. The microRNA biogenesis pathway weighted PGS predicted the risk of ccRCC with an area under the curve (AUC) = 0.642 (95%nCI [0.61–0.67]). Our findings indicate that DNA variants of microRNA machinery genes modulate the risk of ccRCC in Volga-Ural populations. Moreover, larger powerful genome-wide association studies are needed to reveal a wider range of genetic variants affecting microRNA processing. Biological-pathway-based PGSs will advance the development of innovative screening systems for future stratified medicine approaches in ccRCC.

The Role of MicroRNAs in Hyperlipidemia: From Pathogenesis to Therapeutical Application

Hyperlipidemia is a common metabolic disorder with high morbidity and mortality, which brings heavy burden on social. Understanding its pathogenesis and finding its potential therapeutic targets are the focus of current research in this field. In recent years, an increasing number of studies have proved that miRNAs play vital roles in regulating lipid metabolism and were considered as promising therapeutic targets for hyperlipidemia and related diseases. It is demonstrated that miR-191, miR-222, miR-224, miR-27a, miR-378a-3p, miR-140-5p, miR-483, and miR-520d-5p were closely associated with the pathogenesis of hyperlipidemia. In this review, we provide brief overviews about advances in miRNAs in hyperlipidemia and its potential clinical application value.

Exploring the crosstalk between long non-coding RNAs and microRNAs to unravel potential prognostic and therapeutic biomarkers in β-thalassemia

β-thalassemia is a prevalent monogenic disorder characterized by reduced or absent synthesis of the β-globin chain. Although great effort has been made to ameliorate the disease severity of β-thalassemic patients, progress has been stymied due to limited understanding of the detailed molecular mechanism of disease pathogenesis. Recently, non-coding RNAs have been established as key players in regulating various physiological and pathological processes. Many ncRNAs are involved in hematopoiesis and erythroid development. Furthermore, various studies have also reported the complex interplay between different ncRNAs, such as miRNA, lncRNAs, etc. in regulating disease progression and pathogenesis. Both lncRNAs and miRNAs have been identified as independent regulators of globin gene expression and are intricately involved in disease pathogenesis; yet accumulating evidence suggests that the cross-talk between lncRNAs and miRNAs is intricately involved in the underlying globin gene expression, fine-tuning the effect of their independent regulation. In this review, we summarize the current progress of research on the roles of lncRNAs and miRNAs implicated in β-thalassemia disease, including their interactions and regulatory networks. This can provide important insights into the detailed epigenetic regulation of globin gene switching and has the potential to develop novel therapeutic approaches against β-thalassemia.

Role of the Ribonuclease ONCONASE in miRNA Biogenesis and tRNA Processing: Focus on Cancer and Viral Infections

The majority of transcribed RNAs do not codify for proteins, nevertheless they display crucial regulatory functions by affecting the cellular protein expression profile. MicroRNAs (miRNAs) and transfer RNA-derived small RNAs (tsRNAs) are effectors of interfering mechanisms, so that their biogenesis is a tightly regulated process. Onconase (ONC) is an amphibian ribonuclease known for cytotoxicity against tumors and antiviral activity. Additionally, ONC administration in patients resulted in clinical effectiveness and in a well-tolerated feature, at least for lung carcinoma and malignant mesothelioma. Moreover, the ONC therapeutic effects are actually potentiated by cotreatment with many conventional antitumor drugs. This review not only aims to describe the ONC activity occurring either in different tumors or in viral infections but also to analyze the molecular mechanisms underlying ONC pleiotropic and cellular-specific effects. In cancer, data suggest that ONC affects malignant phenotypes by generating tRNA fragments and miRNAs able to downregulate oncogenes expression and upregulate tumor-suppressor proteins. In cells infected by viruses, ONC hampers viral spread by digesting the primer tRNAs necessary for viral DNA replication. In this scenario, new therapeutic tools might be developed by exploiting the action of ONC-elicited RNA derivatives.

CircRNA circ-ATAD1 suppresses miR-618 maturation to participate in colorectal cancer

BACKGROUND

CircRNA circ-ATAD1 has been characterized as an oncogenic circRNA in gastric cancer, while its role in colorectal cancer (CRC) is unknown. This study was carried out to explore the role of circ-ATAD1 in CRC.

METHODS

Paired CRC and adjacent non-tumor tissue samples collected from 64 CRC patients were subjected to RNA extractions and RT-qPCRs to analyze the expression of circ-ATAD1, premature miR-618, and mature miR-618 in CRC. The effects of circ-ATAD1 overexpression on miR-618 maturation were analyzed by transfecting circ-ATAD1 expression vector into CRC cells, followed by determining the expression of premature miR-618 and mature miR-618 using RT-qPCR. The subcellular location of circ-ATAD1 was analyzed by nuclear fractionation assay, and the interaction between circ-ATAD1 and premature miR-618 was analyzed by RNA pull-down assay. The roles of circ-ATAD1, premature miR-618, and mature miR-618 in regulating CRC cell proliferation were explored by CCK-8 assay.

RESULTS

Circ-ATAD1 was upregulated in CRC and predicted poor survival. In addition, circ-ATAD1 was inversely correlated with mature miR-618 but not premature miR-618. In CRC cells, circ-ATAD1 overexpression decreased the level of mature miR-618 but not premature miR-618. Circ-ATAD1 was detected in both the nucleus and cytoplasm. A direct interaction between circ-ATAD1 and miR-618 was observed. Moreover, circ-ATAD1 overexpression reduced the inhibitory effects of miR-618 overexpression on cell proliferation.

CONCLUSION

Circ-ATAD1 is overexpressed in CRC and may suppress miR-618 maturation to participate in CRC.

Optimized Protocol for Plasma-Derived Extracellular Vesicles Loading with Synthetic miRNA Mimic Using Electroporation

Extracellular vesicles (EVs) are a population of particles naturally released by cells to transport biological messages, including nucleic acids. Thus, EVs represent an ideal vehicle to deliver therapeutic miRNAs. The current challenge is the development of efficient protocols to load EVs with exogenous miRNAs. Human plasma is an abundant source of EVs which can be manipulated for therapeutic applications. Despite numerous techniques are currently available to load EVs, all of them present issues which limit their clinical application. Among all, electroporation was shown to be superior to other protocols and to efficiently load plasma-derived EVs with miRNAs. However, also the electroporation procedure presents issues that can reduce the miRNA delivery. In this chapter, we describe a protocol to isolate EVs from human plasma, to load synthetic miRNA mimics using electroporation, to evaluate EV integrity and miRNA loading into EVs. Finally, the analysis of EV functionality allows to investigate the ability of engineered EVs to transfer the miRNAs to target cells and to exploit their biological effects.

CircPTK2 inhibits cell cisplatin (CDDP) resistance by targeting miR-942/TRIM16 axis in non-small cell lung cancer (NSCLC)

In recent years, the problem of cancer resistance has become more and more prominent, seriously affecting treatment efficiency. Circular RNAs (circRNAs) play an important role in cell progression and cancer mechanisms. However, there is a lack of systematic studies on its function in non-small cell lung cancer (NSCLC) resistance. CircPTK2, microRNA-942 (miR-942), and Tripartite motif 16 (TRIM16) levels were detected by Real-time quantitative reverse transcriptase PCR (qRT-PCR). Extracellular acidification rate (ECAR), glucose consumption, and lactate production were assessed using the Seahorse XF96 Glycolysis Analyzer, glucose, and lactate assay kits, respectively. The protein expression was measured with the western bolt Transwell assay was used to determine migration and invasion of transfected cells. (4-5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry were applied to carry out cell proliferation and apoptosis, respectively. The relationship among circPTK2, miR-942, and TRIM16 were determined by using the dual-luciferase reporter assay and RIP assay. circPTK2 (hsa_circ_0008305) and TRIM16 were low expressed, while miR-942 was significantly highly expressed in NSCLC tissues and cell lines. Moreover, overexpression of circPTK2 remarkably inhibited cell growth, metastasis, and glycolysis in A549/CDDP and H1299/CDDP cells. Promotion of miR-942 or inhibition of TRIM16 could reverse the effects of high circPTK2 expression on cell growth, metastasis, and glycolysis in A549/CDDP and H1299/CDDP cells. CircPTK2 overexpression inhibited the growth of A549/CDDP cells in vivo. Furthermore, circPTK2 weakened CDDP resistance of NSCLC through modulating miR-942/TRIM16 axis, providing a novel sight for the treatment of NSCLC and improving the understanding of the CDDP resistance mechanism of NSCLC.

Mapping Research on miRNAs in Cancer: A Global DataAnalysis and Bibliometric Profiling Analysis

miRNAs biomarkers are emerging as an essential part of clinical oncology. Their oncogenic and tumour suppressor properties playing a role in malignancy has generated interest in their potential for use in disease prognosis. While several studies on miRNA have been carried out across the globe, evaluating the clinical implications of miRNAs in cancer diagnosis and prognosis research has currently not been attempted. A study delineating the area of miRNA research, including the topics presently being focused on, the seminal papers in this field, and the direction of research interest, does not exist. This study aims to conduct a large-scale, global data analysis and bibliometric profiling analysis of studies to evaluate the research output of clinical implications of miRNAs in cancer diagnosis and prognosis listed in the SCOPUS database. A systematic search strategy was followed to identify and extract all relevant studies, subsequently analysed to generate a bibliometric map. SPSS software (version 27) was used to calculate bibliometric indicators or parameters for analysis, such as year and country of affiliation with leading authors, journals, and institutions. It is also used to analyse annual research outputs, including total citations and the number of times it has been cited with productive nations and H-index. The number of global research articles retrieved for miRNA-Cancer research over the study period 2003 to 2019 was 18,636. Between 2012 and 2019, the growth rate of global publications is six times (n = 15,959; 90.71 percent articles) that of 2003 to 2011. (2704; 9.29 per cent articles). China published the most publications in the field of miRNA in cancer (n = 7782; 41%), while the United States had the most citations (n = 327,538; 48%) during the time span. Of these journals, Oncotarget has the highest percentage of article publications. The journal Cancer Research had the most citations (n = 41,876), with 6.20 per cent (n = 41,876). This study revealed a wide variety of journals in which miRNA-Cancer research are published; these bibliometric parameters exhibit crucial clinical information on performance assessment of research productivity and quality of research output. Therefore, this study provides a helpful reference for clinical oncologists, cancer scientists, policy decision-makers and clinical data researchers.

Long Non-coding RNA CBR3 Antisense RNA 1 is Downregulated in Colorectal Cancer and Inhibits miR-29a-Mediated Cell Migration and Invasion

Although CBR3 Antisense RNA 1 (CBR3-AS1) has been characterized as an oncogenic long non-coding RNA (lncRNA) in several cancers, a recent study reported the downregulation of CBR3-AS1 in colorectal cancer (CRC). Therefore, we analyzed its role in CRC. CBR3-AS1 and microRNA-29a (miR-29a) expression in tissue samples from CRC patients were analyzed by RT-qPCR. The interaction between CBR3-AS1 and miR-29a was predicted by IntaRNA and validated by RNA pull-down assay. The location of CBR3-AS1 was analyzed by nuclear fractionation assay. CBR3-AS1 overexpression was performed to analyze its role in miR-29a expression. The roles of CBR3-AS1 and miR-29a in CRC cell migration and invasion were analyzed by Transwell assay. CBR3-AS1 was downregulated, and miR-29a was upregulated in CRC. CBR3-AS1 and miR-29a directly interacted with each other. CBR3-AS1 was localized in both nucleus and cytoplasm fractions. CBR3-AS1 overexpression failed to alter miR-29a expression but reduced its enhancing effects on cell invasion and migration. CBR3-AS1 is downregulated in CRC and inhibits miR-29a-mediated cell migration and invasion by sponging miR-29a.

The LOXL1 antisense RNA 1 (LOXL1-AS1)/microRNA-423-5p (miR-423-5p)/ectodermal-neural cortex 1 (ENC1) axis promotes cervical cancer through the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway

As the fourth commonest malignancy among females worldwide, cervical cancer (CC) poses a huge challenge to human health. The pivotal regulatory roles of lncRNAs in cancers have been highlighted. LOXL1 antisense RNA 1 (LOXL1-AS1) has been reported to play a key role in cervical squamous cell carcinoma and other various cancers. Thus, we investigated the roles and mechanisms of lncRNA LOXL1-AS1 in CC. The in vivo experiments demonstrated that LOXL1-AS1 downregulation inhibited tumor growth and metastasis and proliferation of CC cells. The results of RT-qPCR demonstrated that LOXL1-AS1 and ectodermal-neural cortex 1 (ENC1) expression levels were upregulated in CC cells and tissues, while microRNA-423-5p (miR-423-5p) level was downregulated. As subcellular fractionation assays, RNA pull down assays and luciferase reporter assays revealed, LOXL1-AS1 bound to miR-423-5p and miR-423-5p targeted ENC1. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, wound healing and colony formation assays demonstrated that miR-423-5p upregulation and LOXL1-AS1 downregulation inhibited CC cell proliferation and migration, while ENC1 upregulation attenuated the inhibitory effects of miR-423-5p upregulation on the malignant phenotypes of CC cells. Western blotting was conducted to measure protein levels and the results showed that ENC1 knockdown inhibited the activation of ERK/MEK pathway. In summary, the LOXL1-AS1/miR-423-5p/ENC1 axis accelerates CC development through the MEK/ERK pathway.

Characterization of the first microRNA in human CDH1 that affects cell cycle and apoptosis and indicates breast cancers progression

The E-cadherin protein (Cadherin 1, gene: CDH1), a master regulator of the human epithelial homeostasis, contributes to the epithelial-mesenchymal transition (EMT) which confers cell migratory features to the cells. The EMT is central to many pathophysiological changes in cancer. Therefore, a better understanding of this regulatory scenario is beneficial for therapeutic regiments. The CDH1 gene is approximately 100 kbp long and consists of 16 exons with a relatively large second intron. Since none microRNA (miRNA) has been identified in CDH1 up to now we screened the CDH1 gene for promising miRNA hairpin structures in silico. Out of the 27 hairpin structures we identified, one stable RNA fold with a promising sequence motive was selected for experimental verification. The exogenous validation of the hairpin sequence was performed by transfection of HEK293T cells and the mature miRNA sequences could be verified by quantitative polymerase chain reaction. The endogenous expression of the mature miRNA provisionally named CDH1-i2-miR-1 could be confirmed in two normal (HEK293T, HUVEK) and five cancer cell lines (MCF7, MDA-MB-231, SW480, HT-29, A549). The functional characterization by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed a suppression of HEK293T cell proliferation. A flow cytometry-based approach showed the ability of CDH1-i2-miR-1 to arrest transfected cells on a G2/M state while annexin staining exemplified an apoptotic effect. BAX and PTEN expression levels were affected following the overexpression with the new miRNA. The in vivo expression level was assessed in 35 breast tumor tissues and their paired nonmalignant marginal part. A fourfold downregulation in the tumor specimens compared to their marginal controls could be observed. It can be concluded that the sequence of the hub gene CDH1 harbors at least one miRNA but eventually even more relevant for the pathophysiology of breast cancer.

miR-671-5p Inhibition by MSI1 Promotes Glioblastoma Tumorigenesis via Radioresistance, Tumor Motility and Cancer Stem-like Cell Properties

MicroRNAs (miRNAs) could be potential biomarkers for glioblastoma multiforme (GBM) prognosis and response to therapeutic agents. We previously demonstrated that the cancer stem cell marker Musashi-1 (MSI1) is an RNA binding protein that promotes radioresistance by increasing downstream RNA stability. To identify that MSI1 interacts with miRNAs and attenuates their function, we also get candidate miRNAs from the mRNA seq by predicting with TargetScan software. miR-671-5p in GBM cells interacts with MSI1 by intersecting the precipitated miRNAs with the predicted miRNAs. Notably, overexpression of MSI1 reversed the inhibitory effect of miR-671-5p. The phenotype of miR-671-5p in GBM cells could affect radiosensitivity by modulating the posttranscriptional activity of STAT3. In addition, miR-671-5p could attenuate tumor migration and cancer stem cell (CSC) characteristics by repressing the posttranscriptional activity of TRAF2. MSI1 may regulate GBM radioresistance, CSCs and tumor motility through miR-671-5p inhibition to increasing STAT3 and TRAF2 presentation. In vivo, the GBM tumor size was inversely correlated with miR-671-5p expression, but tumorigenesis was promoted by STAT3 and TRAF2 activation in the miR-671-5p-positive GBM population. miR-671-5p could be activated as a novel therapeutic target for GBM and has potential application as a predictive biomarker of glioblastoma prognosis.

Long noncoding RNA Meg3 sponges miR-708 to inhibit intestinal tumorigenesis via SOCS3-repressed cancer stem cells growth

BACKGROUND

Colorectal cancer (CRC) remains the most common gastrointestinal cancer and a leading cause of cancer deaths worldwide, with most showing pathologies indicating the malignant transformation of early stage intestinal stem cells. The long non-coding RNA Meg3, which functions as a tumor suppressor, has been reported to be abnormal in multiple tumorigenesis events; however, the underlying mechanism by which Meg3 contributes to the malignant proliferation of colonic stem cells remains unclear.

METHODS

We analyzed the expression levels of Meg3, miR-708, and SOCS3 in samples from Apc loss-of-function (Apc^min) mice and patients with CRC, particularly in colonic crypt cells. Apc^min mice and AMO/DSS-induced mice model (in vivo) and organoid culture system (in vitro) were used to explore the effect of the Meg3/miR-708/SOCS3 axis on tumorigenesis in the colon. In vitro, we performed RNApull-down, RNA immunoprecipitation, and luciferase reporter assays using DLD1 and RKO cell lines.

FINDINGS

The Meg3/miR-708/SOCS3 signaling axis plays a critical role in the early stage of CRC development. Our data showed Meg3 levels negatively correlate with miR-708 levels both in clinical samples and in the Apc^min mouse model, which indicated that Meg3 acts as a competitive endogenous RNA (ceRNA) of miR-708. Then, miR-708 served as an oncogene, inducing neoplasia in both Apc^min mice and cultured colonic organoids. Put together, miR-708 appears to promote malignant proliferation of colonic stem cells by targeting SOCS3/STAT3 signaling.

INTERPRETATION

These data revealed that Meg3 sponges miR-708 to inhibit CRC development via SOCS3-mediated repression of the malignant proliferation of colonic stem cells. The Meg3/miR-708/SOCS3 signaling axis provides potential targets for the diagnosis and treatment of CRC, particularly early stage CRC.

CircNUP98 Suppresses the Maturation of miR-519a-3p in Glioblastoma

Circular RNA (circNUP98) has been reported to promote renal cancer; however, its role in other cancers is unknown. The function of circNUP98 in glioblastoma (GB) cancer was explored in this study. A total of 58 GB tissue samples were collected to study the expression of circNUP98 and miR-519a-3p [both the mature and pre-mature microRNA (miRNA)] by quantitative real-time PCR (RT-qPCR) and heatmap analysis. The subcellular location that expresses circNUP98 was analyzed by nuclear fractionation assay. RNA pull-down assay was performed to evaluate the interaction between circNUP98 and pre-mature miR-519a-3p. Overexpression assays were performed to investigate the role of circNUP98 in the regulation of both the mature and pre-mature miR-519a-3p. The role of circNUP98 and miR-519a-3p in GB cell proliferation was explored by 5-bromo-2-deoxyuridine (BrdU) assay and was assessed in mouse xenograft model. Heatmap analysis showed that circNUP98 and pre-mature miR-519a-3p were upregulated in GB, while mature miR-519a-3p was downregulated in GB. Across the cancer tissues, circNUP98 was inversely correlated with mature miR-519a-3p, but positively correlated with pre-mature miR-519a-3p. In GB cells, circNUP98 was localized to both the nucleus and cytoplasm and it interacted with pre-mature miR-519a-3p. In GB cells, circNUP98 increased the expression levels of pre-mature miR-519a-3p and decreased the expression levels of mature miR-519a-3p. BrdU and cholecystokinin octapeptide (CCK-8) assays illustrated that overexpression of circNUP98 reduced the inhibitory effects of miR-519a-3p on cell proliferation. CircNUP98 contributed to larger tumors, which resulted in significantly reduced mice survival. CircNUP98 suppresses the maturation of miR-519a-3p to promote GB cell proliferation.

Circ-ATAD1 is overexpressed in osteosarcoma (OS) and suppresses the maturation of miR-154-5p to increase cell invasion and migration

Background

Circ-ATAD1 plays an oncogenic role in gastric cancer. However, its roles in other cancers are unclear. We aimed to analyze the role of circ-ATAD1 in osteosarcoma (OS).

Methods

The expression levels of circ-ATAD1, mature miR-154-5p, and premature miR-154-5p in paired OS and non-tumor tissues from 56 OS patients were determined using RT-qPCR. Nuclear fractionation assay was performed to analyze the subcellular location of circ-ATAD1. The interaction between circ-ATAD1 and premature miR-154-5p was analyzed using RNA pull-down assay. The role of circ-ATAD1 in regulating miR-154-5p maturation was analyzed using RT-qPCR in cells with overexpression. Transwell assays were performed to analyze the roles of circ-ATAD1 and miR-154-5p in regulating OS cell invasion and migration.

Results

Circ-ATAD1 was overexpressed in OS compared to non-tumor tissues and was detected in the nuclei of OS cells. Mature miR-154-5p, but not premature miR-154-5p, was downregulated in OS tissues compared to non-tumor tissues and was inversely correlated with circ-ATAD1. In OS cells, circ-ATAD1 overexpression decreased the expression of mature miR-154-5p, but not premature miR-154-5p. Transwell assay analysis showed that circ-ATAD1 overexpression increased cell invasion and migration, and mature miR-154-5p overexpression suppressed these cell behaviors. In addition, circ-ATAD1 overexpression reduced the effects of mature miR-154-5p overexpression on cell behaviors.

Conclusions

Circ-ATAD1 is overexpressed in OS and suppresses miR-154-5p maturation to increase cell invasion and migration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02809-4.

MiR-1224 Acts as a Prognostic Biomarker and Inhibits the Progression of Gastric Cancer by Targeting SATB1

Objective

MiR-1224 has been reported to exhibit abnormal expression in several tumors. However, the expressing pattern and roles of miR-1224 in gastric cancer (GC) remain unclear. Our current research aimed to explore the potential involvement of miR-1224 in the GC progression.

Materials and Methods

The expression of miR-1224 was examined in tissue samples of 128 GC patients and cell lines by RT-PCR. Besides, the associations of miR-1224 expressions with clinicopathologic features and prognosis of GC patients were analyzed. Then, the possible influences of miR-1224 on cell proliferation and cell migration were determined. Afterward, the molecular target of miR-1224 was identified using bioinformatics assays and confirmed experimentally. Finally, RT-PCR and Western blot assays were performed to investigate the effect of the abnormal miR-1224 expression on the EMT and Wnt/β-catenin pathway.

Results

miR-1224 was lowly expressed in the GC specimens and cell lines due to T classification and TNM stage. Survival assays demonstrated that GC patients with low expressions of miR-1224 possessed poor overall survivals. Moreover, in vitro and in vivo assays revealed that the overexpression of miR-1224 inhibited cell proliferation, migration, and invasion in GC cells. SATB homeobox 1 (SATB1) was verified as a direct target of miR-1224 in GC. Furthermore, β-catenin and c-myc were significantly inhibited in miR-1224-overexpression cells.

Conclusions

Our findings highlight the potential of miR-1224 as a therapeutic target and novel biomarker for GC patients

The potential use of microRNAs as a therapeutic strategy for SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, there is no effective therapeutic approach for treating SARS-CoV-2 infections. MicroRNAs (miRNAs) have been recognized to target the viral genome directly or indirectly, thereby inhibiting viral replication. Several studies have demonstrated that host miRNAs target different sites in SARS-CoV-2 RNA and constrain the production of essential viral proteins. Furthermore, miRNAs have lower toxicity, are more immunogenic, and are more diverse than protein-based and even plasmid-DNA-based therapeutic agents. In this review, we emphasize the role of miRNAs in viral infection and their potential use as therapeutic agents against COVID-19 disease. The potential of novel miRNA delivery strategies, especially EDV™ nanocells, for targeting lung tissue for treatment of SARS-CoV-2 infection is also discussed.

Serum circulating miRNA-342-3p as a potential diagnostic biomarker in parathyroid carcinomas: A pilot study

Objective

To compare the serum miRNA expression profiles between patients with benign and malignant parathyroid tumours.

Background

Despite recent advances in molecular biology, a histological tissue biopsy is still the method of choice used to diagnose most cancers. The preoperative cytology is not an applicable method for diagnosis of parathyroid cancer (PC); therefore, huge interest exists in terms of finding alternative methodologies to seek specific cancer biomarkers.

Design

A retrospective cross‐sectional study.

Patients and Methods

Serum samples of patients with PC (n = 13) and parathyroid adenoma (PA) (n = 11), age (p = .999) and sex (p = .999) were matched and examined via the simultaneous comparative expression analysis of 754 microRNAs (miRNAs). The «TaqMan OpenArray Human MicroRNA Panel» (Applied Biosystems) was used to conduct real‐time PCRs using the «QuantStudio 12К Flex» station (Life Technologies).

Results

According to the results of a pilot study, significant changes in expression levels between the PC group and the PA group (control) (p < .05) were observed for 17 miRNAs. Among them, the downregulation of miRNA‐342‐3p met the Benjamini‐Hochberg adjustment criteria for multiple comparisons (p = .02).

Conclusions

Serum miRNA‐342‐3p could be a promising biomarker for PC to improve diagnosis and prognosis.

Novel miR-5088-5p promotes malignancy of breast cancer by inhibiting DBC2

Breast cancer is the most common female cancer in the world. Despite the active research on metastatic breast cancer, the treatment of breast cancer patients is still difficult because the mechanism is not well known. Therefore, research on new targets and mechanisms for diagnosis and treatment of breast cancer patients is required. On the other hand, microRNA (miRNA) has the advantage of simultaneously regulating the expression of many target genes, so it has been proposed as an effective biomarker for the treatment of various diseases including cancer. This study analyzed the role and mechanism of DBC2 (deleted in breast cancer 2), which is known to inhibit its expression in breast cancer, and proposed microRNA (miR)-5088-5p, which regulates its expression. It was revealed that the biogenesis of miR-5088-5p was upregulated by hypomethylation of its promoter, promoted by Fyn, and was involved in malignancy in breast cancer. With the use of the cellular level, clinical samples, and published data, we verified that the expression patterns of DBC2 and miR-5088-5p were negatively related, suggesting the potential as novel biomarkers for the diagnosis of breast cancer patients.

MicroRNAs as Potential Predictors of Response to CDK4/6 Inhibitor Treatment

Simple Summary

MicroRNAs are endogenous non-coding 20–22 nucleotide long RNAs that play a fundamental role in the post-transcriptional control of gene expression. Consequently, microRNAs are involved in multiple biological processes of cancer and could be used as biomarkers with prognostic and predictive significance. Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have become a mainstay of treatment for patients with advanced hormone receptor-positive (HR) breast cancer. Despite the initial high response rates, approximately 10% of patients demonstrate primary resistance to CDK4/6 inhibitors while acquired resistance is almost inevitable. Considering the fundamental role of miRNAs in tumorigenesis, we aimed to explore the potential involvement of microRNAs in response to CDK4/6 inhibition in solid tumors. A number of microRNAs were shown to confer resistance or sensitivity to CDK4/6 inhibitors in preclinical studies, although this remains to be proved in human studies.

Abstract

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have emerged as novel treatment options in the management of advanced or metastatic breast cancer. MicroRNAs are endogenous non-coding 19–22-nucleotide-long RNAs that regulate gene expression in development and tumorigenesis. Herein, we systematically review all microRNAs associated with response to CDK4/6 inhibitors in solid tumors and hematological malignancies. Eligible articles were identified by a search of the MEDLINE and ClinicalTrials.gov databases for the period up to1 January 2021; the algorithm consisted of a predefined combination of the words “microRNAs”, “cancer” and “CDK 4/6 inhibitors”. Overall, 15 studies were retrieved. Six microRNAs (miR-126, miR-326, miR3613-3p, miR-29b-3p, miR-497 and miR-17-92) were associated with sensitivity to CDK4/6 inhibitors. Conversely, six microRNAs (miR-193b, miR-432-5p, miR-200a, miR-223, Let-7a and miR-21) conferred resistance to treatment with CDK4/6 inhibitors. An additional number of microRNAs (miR-124a, miR9, miR200b and miR-106b) were shown to mediate cellular response to CDK4/6 inhibitors without affecting sensitivity to treatment. Collectively, our review provides evidence that microRNAs could serve as predictive biomarkers for treatment with CDK4/6 inhibitors. Moreover, microRNA-targeted therapy could potentially maximize sensitivity to CDK4/6 inhibition.

MiR-7-5p inhibits thyroid cell proliferation by targeting the EGFR/MAPK and IRS2/PI3K signaling pathways

The aberrant expression of miRNAs is often correlated to tumor development. MiR-7-5p is a recently discovered downregulated miRNA in thyroid papillary carcinoma (PTC). The goal of this project was to characterize its functional role in thyroid tumorigenesis and to identify the targeted modulated pathways. MiR-7-5p overexpression following transfection in TPC1 and HT-ori3 cells decreased proliferation of the two thyroid cell lines. Analysis of global transcriptome modifications showed that miR-7-5p inhibits thyroid cell proliferation by modulating the MAPK and PI3K signaling pathways which are both necessary for normal thyroid proliferation and play central roles in PTC tumorigenesis. Several effectors of these pathways are indeed targets of miR-7-5p, among which EGFR and IRS2, two upstream activators. We confirmed the upregulation of IRS2 and EGFR in human PTC and showed the existence of a negative correlation between the decreased expression of miR-7-5p and the increased expression of IRS2 or EGFR. Our results thus support a tumor-suppressor activity of miR-7-5p. The decreased expression of miR-7-5p during PTC tumorigenesis might give the cells a proliferative advantage and delivery of miR-7-5p may represent an innovative approach for therapy.

Recent development of bioinformatics tools for microRNA target prediction

MicroRNAs (miRNAs) are central players that regulate the post-transcriptional processes of gene expression. Binding of miRNAs to target mRNAs can repress their translation by inducing the degradation or by inhibiting the translation of the target mRNAs. High-throughput experimental approaches for miRNA target identification are costly and time-consuming, depending on various factors. It is vitally important to develop the bioinformatics methods for accurately predicting miRNA targets. With the increase of RNA sequences in the post-genomic era, bioinformatics methods are being developed for miRNA studies specially for miRNA target prediction. This review summarizes the current development of state-of-the-art bioinformatics tools for miRNA target prediction, points out the progress and limitations of the available miRNA databases, and their working principles. Finally, we discuss the caveat and perspectives of the next-generation algorithms for the prediction of miRNA targets.

Roles of miR-204 in retinal development and maintenance

The retina is the innermost part of the eye of most vertebrates and it is essential for vision. The development, maintenance, and function of this laminated structure is tightly regulated by numerous genes. Deficiencies in the expression of these genes as well as deregulation of various molecular mechanisms can cause retinopathies and blindness. MicroRNAs (miRNAs) are one of the most important and effective molecular regulatory mechanisms that underlie the biology of the retina. miRNAs have specific functional roles in the development and maintenance of different retinal layers and retinal cell types. While previous studies have reported a large number of miRNAs linked to development, maintenance and diseases of the retina, no comprehensive study has properly discussed and integrated data from these studies. Given the particular importance of miR-204 in retinal biology, we intend to critically discuss the expression and functional significance of this miRNA in the development, maintenance, and pathologies of the retina. Moreover, we explore biological processes through which miR-204 influences retinal pathophysiology. This review highlights the crucial functions of miR-204 in the retina and suggests the putative mechanism of miR-204 action in retinal biology.

Roles of exosomes in diagnosis and treatment of colorectal cancer

Exosomes are extracellular vesicles that mediate intercellular communication. They contain different molecules, such as DNA, RNA, lipid, and protein, playing essential roles in the pathogenesis of colorectal cancer (CRC). Exosomes derived from CRC are implicated in tumorigenesis, chemotherapy resistance, and metastasis. Besides, they can enhance CRC progression by increasing tumor cell proliferation, reducing apoptosis mechanistically through altering particular essential regulatory genes, or controlling several signaling pathways. Therefore, exosomes derived from CRC are essential biomarkers and can be used in the diagnosis. Indeed, it is crucial to understand the role of exosomes in CRC, which is necessary to develop diagnostic and therapeutic strategies for early detection and treatment. In the present review, we discuss the roles of exosomes in the diagnosis and treatment of CRC.

Knockdown of long non-coding RNA NEAT1 relieves the inflammatory response of spinal cord injury through targeting miR-211-5p/MAPK1 axis

Spinal cord injury (SCI) is a refractory disease often accompanied by inflammation. Long non-coding RNA NEAT1 (lncRNA NEAT1) was reported to be involved in the expression of the inflammasomes, while the regulatory effect of NEAT1 on SCI was poorly investigated. Herein, we carried out further studies on the pathogenesis of SCI. PC-12 cells were incubated with lipopolysaccharide (LPS) to induce inflammation. Western blotting assay was used to measure the protein expression levels. RNA expression levels were analyzed using RT-qPCR. Cell counting kit 8 and flow cytometry assays were used to separately determine the cell viability and apoptosis rate. The targeted relationships were verified by luciferase reporter and RNA pull-down assays. It was found that LPS induced inflammation in the PC-12 cells, leading to significantly higher cell apoptosis rate and lower viability, and the expression level of NEAT1 was elevated by LPS. However, knockdown of NEAT1 partially reversed the effects of LPS. Subsequently, the potential interaction between NEAT1 and miR-211-5p was validated and miR-211-5p inhibitor was further confirmed to antagonize the effects of NEAT knockdown. The downstream target gene of miR-211-5p was predicted and verified to be MAPK1. In addition, overexpression of MAPK1 was proved to antagonize the effects of NEAT1 knockdown. Taken together, the knockdown of NEAT1 remarkably alleviated the inflammation of SCI via miR-211-5p/MAPK1 axis.

CircCA12 Promotes Malignant Process via Sponging miR-1184 and Upregulating RAS Family in Bladder Cancer

Circular RNAs (circRNAs) are a panel of non-coding RNAs that mediate the regulation of gene expression, as well as pathological responses. Nonetheless, the function and expression pattern of circRNAs in urinary bladder cancer (UBC) remain unclear. Herein, we examined the function of circCA12 in UBC development. qRT-PCR results demonstrated remarkable circCA12 upregulation in UBC cell lines, as well as tissues. CCK-8, colony formation, and xenograft assays were employed to determine the effect of circCA12 on UBC. Our data illustrated silencing circCA12 repressed the proliferation along with the colony-formation capability of UBC cells. The migration and metastasis potential of UBC cells were remarkably abated in vivo, as well as in vitro after transfection with si-cirCA12 or sh-circCA12. Moreover, luciferase reporter and RIP assays indicated that circCA12 binds to miRNA-1184 through sponging miRNA, thereby up-regulating the expression of RAS family genes (NRAS, KRAS, and HRAS). In conclusion, the circCA12/miRNA-1184/RAS family was identified as a regulatory axis in UBC progression.