miRNA Biology Research Articles

A review on gut microbiota and miRNA crosstalk: implications for Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and progressive neuronal damage. Recent research has highlighted the significant roles of the gut microbiota and microRNAs (miRNAs) in the pathogenesis of AD. This review explores the intricate interaction between gut microbiota and miRNAs, emphasizing their combined impact on Alzheimer's progression. First, we discuss the bidirectional communication within the gut-brain axis and how gut dysbiosis contributes to neuroinflammation and neurodegeneration in AD. Changes in gut microbiota composition in Alzheimer's patients have been linked to inflammation, which exacerbates disease progression. Next, we delve into the biology of miRNAs, focusing on their roles in gene regulation, neurodevelopment, and neurodegeneration. Dysregulated miRNAs are implicated in AD pathogenesis, influencing key processes like inflammation, tau pathology, and amyloid deposition. We then examine how the gut microbiota modulates miRNA expression, particularly in the brain, potentially altering neuroinflammatory responses and synaptic plasticity. The interplay between gut microbiota and miRNAs also affects blood-brain barrier integrity, further contributing to Alzheimer's pathology. Lastly, we explore therapeutic strategies targeting this gut microbiota-miRNA axis, including probiotics, prebiotics, and dietary interventions, aiming to modulate miRNA expression and improve AD outcomes. While promising, challenges remain in fully elucidating these interactions and translating them into effective therapies. This review highlights the importance of understanding the gut microbiota-miRNA relationship in AD, offering potential pathways for novel therapeutic approaches aimed at mitigating the disease's progression.

Abstract PR011: Multipronged SMAD Pathway Targeting by LiPBAE miR-590-3p NanomiRs Inhibits Recurrent Glioblastoma Growth and Prolongs Survival

Abstract Despite aggressive therapy consisting of surgery followed by radio/chemotherapy Glioblastoma (GBM) recurs in almost all patients and, currently, there are no proven therapies to treat recurrent GBM (rGBM). Recent developments in nanomedicine provide new and promising opportunities to develop new targeted therapeutics to treat brain tumors. In this study we combine bioinformatics, forward-thinking understanding of miRNA biology and cutting-edge nucleic acid delivery vehicles to advance targeted therapeutics for rGBM. Bioinformatic analysis of RNA sequencing from GSCs and clinical rGBM specimens identified TGF-beta receptor II (TGFBR2) signaling as a targetable pathway in rGBM. Mechanistically, we show that alterations in chromatin state driven by stem-cell driving events are conducive to a therapy-resistant state induced by TGFBR2. We show that blocking TGFBR2 via molecular and pharmacological approaches decreases the stem cell capacity, cell viability and re-sensitizes clinical rGBM isolates to temozolomide (TMZ) in vitro. Network analysis of SMAD2/3 targets enriched in rGBM predicted a subset of miRNAs that can target multiple genes within this set. Notably, miR-590-3p was predicted to inhibit 37 SMAD 2/3 gene targets that are also enriched in rGBMs. Bioinformatics analysis also showed that expression of 24 of those 37 miR-590-3p targets are positively correlated with TGFBR2 expression in rGBM clinical specimens. Consistent with these predictions, miR-590-3p inhibited expression of 25 of the 37 targets across 3 distinct therapy-resistant GSC isolates. To translate these in vitro finding, we developed novel bioreducible Lipophilic poly(β-amino ester) nanoparticles (LiPBAEs) for in vivo miRNA delivery. Following direct intratumoral infusion, these nanomiRs efficiently distribute through the tumors and spatial transcriptomic analysis (STA) found a decrease in 34 out of the 37 miR- 590-3p targets in animals that received the active nanomiR compared to control miRNA. Furthermore, STA identified 3 cell populations with distinct transcriptomic profiles reflecting a gradient pharmacodynamic response within tumors that received miR-590-3p nanomiRs with decreasing target expression towards the core of the tumor closest to catheter tip placement. To test the effect of 590-3p nanomiR therapy on survival, animals bearing pre-established intracranial rGBM xenografts received three infusions of either control or miR-590-3p nanomiRs every other day beginning on post-implantation day 7. All 10 animals treated with control nanomiRs were either dead or premorbid requiring euthanasia by post-implantation day 23. In contrast, 3 of 10 animals treated with miR-590-3p nanomiRs remained alive and healthy by post-implantation day 45, at which time the experiment was terminated. These results show that miRNA-based targeted therapeutics provide new opportunities to treat rGBM and bypass the resistance that is developed to standard of care. Citation Format: Hernando Lopez-Bertoni, Jack Korleski, Sophie Sall, Kathryn Luly, Maya K Johnson, Amanda L Johnson, Harmon Khela, Bachchu Lal, TC Taylor, Jean Micheal Ashby, Hector Alonso, Alice Li, Stephany Tzeng, John Laterra, Jordan J Green. Multipronged SMAD Pathway Targeting by LiPBAE miR-590-3p NanomiRs Inhibits Recurrent Glioblastoma Growth and Prolongs Survival [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr PR011.

Harnessing natural compounds to modulate miRNAs in breast cancer therapy.

Breast cancer's complexity and heterogeneity continue to present significant challenges in its treatment and management. Emerging research has underscored the pivotal role of microRNAs (miRNAs) in breast cancer pathogenesis, acting as crucial regulators of gene expression. This review delivers an in-depth analysis of miRNAs, highlighting their dual functions as both oncogenes and tumor suppressors, and detailing their impact on key biological processes, including cell proliferation, apoptosis, and metastasis. The mechanisms underlying miRNA action, particularly their interactions with target mRNAs and the factors influencing these dynamics, are thoroughly explored. Additionally, the review discusses the therapeutic prospects of miRNAs, with a focus on innovative delivery systems like nanoparticles that improve the stability and effectiveness of miRNA-based therapies. It also addresses the anticancer effects of natural compounds, such as genistein, hesperidin, quercetin, curcumin, resveratrol, epigallocatechin-3-gallate (EGCG), and glyceollins, which modulate miRNA expression and contribute to tumor growth inhibition. These advances seek to address the limitations of conventional therapies, paving the way for targeted interventions in breast cancer. By integrating current insights on miRNA biology, therapeutic strategies, and the potential of natural products to regulate miRNA expression, this review aims to shed light on miRNA- and natural product-based approaches as promising avenues for enhancing breast cancer treatment outcomes.

Serum microRNA Biomarker Expression in HIV and TB: A Concise Overview.

Non-coding RNAs (ncRNAs), specifically MicroRNAs or miRNAs, are now under-stood to be essential regulators in the complex field of gene expression. By selectively bind-ing to certain mRNA targets, these tiny RNA molecules control the expression of genes., leading to mRNA degradation or translational repression. The discovery of miRNAs has sig-nificantly advanced biomedical research, particularly in elucidating the molecular mecha-nisms underlying various diseases and exploring innovative therapeutic approaches. Recent progress in miRNA research has provided insights into their biogenesis, functional roles, and potential clinical applications. Despite the absence of established methodologies for clinical implementation, miRNAs show great promise as diagnostic and therapeutic agents for a wide array of diseases. Their distinctive attributes, such as high specificity, sensitivity, and accessibility, position them as ideal candidates for biomarker development and targeted therapy. Achieving a comprehensive understanding of miRNA biology and functionality is crucial to fully harnessing their potential in medicine. Ongoing research efforts aim to un-ravel the intricate mechanisms of miRNA-mediated gene regulation and to develop novel approaches for utilizing miRNAs in disease diagnosis, prognosis, and treatment. This review provides a comprehensive analysis of current knowledge on miRNAs, focusing on their bio-genesis, regulatory mechanisms, and potential clinical applications. By synthesizing existing evidence and highlighting key research findings, this review aims to inspire further explora-tion into the diverse roles of miRNAs in health and disease. Ultimately, this endeavour could result in the development of innovative miRNA-based diagnostic and therapeutic strategies.

Abstract P418: Placental small-RNA sequencing reveals a distinct microRNA signature and its functional relevance in a preeclamptic rat model

Introduction: Despite considerable research over the last few decades, molecular mechanisms that govern preeclamptic (PE) pathogenesis are poorly understood. Recent studies focussed on mechanistic exploration documented that microRNAs (miRNAs) regulate critical processes (endothelial dysfunction, inflammation, oxidative stress) pertinent to PE pathology. However, to the best of our knowledge, a complete placental miRNA expression profiling has not been undertaken. Given the complexity surrounding miRNA biology, a comprehensive miRNA profiling would greatly aid our efforts in better understanding PE pathology. Objective: The objective of the current study was to perform a comprehensive profiling of placental miRNAs in PE rat (reduced perfusion pressure;RUPP) model, and identify their functional relevance. Methods: RUPP surgery was performed on gestational day (GD)14. Blood pressures (carotid catheterization) were collected on GD19, and placenta (~5mg) was used to isolate miRNA (Qiagen’s miRNeasy Micro Kit). Small RNA sequencing (s-RNA seq) was performed by Illumina sequencer(NEXTFLEX Kit). Enrichment analysis was performed using Cytoscape(BINGO, overrepresentation, p=0.05). Functional associations were retrieved using TAM2.0. Results: RUPP rats showed higher MAP (123.8±1.51 vs.98.70±1.53 mmHg, n=10, p<0.0001) vs.control rats. S-RNA seq revealed a total of 142 (40 up and 102 down) differentially regulated (diff-reg) miRNAs in RUPPs. Of these, the top 5 diff-reg miRNAs were; miR-211-3p, miR-628, miR-6324, miR-363-5p, miR-6329 (up) and miR-3587, miR-29b-3p, miR-3556a, miR-29a-3p, miR-21-3p (down). Interestingly, TAM2.0 revealed that these miRNAs are involved in immune response (miR-363, miR-21, miR-29), B-cell differentiation (miR-628), T-cell activation (miR-21), adipogenesis, lipid metabolism (miR-211, miR-29, miR-21), and angiogenesis (miR-363, miR-21) all of which are relevant to PE. Further, enrichment analysis revealed that the top 10 significantly enriched terms include, regulation of transport, cell-cell signaling, calcium ion-dependent exocytosis (BP); synaptic vesicle, perinuclear region of cytoplasm, membrane bound/clathrin-coated vesicle (CC); glycoprotein binding, protein dimerization activity, myosin head/neck binding (MF). Conclusions: Our findings demonstrate that dysregulated placental miRNAs may be involved in PE pathogenesis. Future studies building on these preliminary findings may help identify candidate miRNA for therapeutic manipulation.

Potential Use of MicroRNA Technology in Thalassemia Therapy.

Thalassemia encompasses a group of inherited hemoglobin disorders characterized by reduced or absent production of the α- or β-globin chains, leading to anemia and other complications. Current management relies on lifelong blood transfusions and iron chelation, which is burdensome for patients. This review summarizes the emerging therapeutic potential of modulating microRNAs (miRNAs) to treat thalassemia. MiRNAs are small non-coding RNAs that regulate gene expression through sequence-specific binding to messenger RNAs (mRNAs). While they commonly repress gene expression by binding to the 3' untranslated regions (UTRs) of target mRNAs, miRNAs can also interact with 5'UTRs and gene promoters to activate gene expression. Many miRNAs are now recognized as critical regulators of erythropoiesis and are abnormally expressed in β-thalassemia. Therapeutically restoring levels of deficient miRNAs or inhibiting overexpression through miRNA mimics or inhibitors (antagomir), respectively, has shown preclinical efficacy in ameliorating thalassemic phenotypes. The miR-144/451 cluster is especially compelling for targeted upregulation to reactivate fetal hemoglobin synthesis. Advances in delivery systems are addressing previous challenges in stability and targeting of miRNA-based drugs. While still early, gene therapy studies suggest combinatorial approaches with miRNA modulation may provide synergistic benefits. Several key considerations remain including enhancing delivery, minimizing off-target effects, and demonstrating long-term safety and efficacy. While no miRNA therapies have yet progressed to clinical testing for thalassemia specifically, important lessons are being learned through clinical trials for other diseases and conditions, such as cancer, cardiovascular diseases, and viral. If limitations can be overcome through multi-disciplinary collaboration, miRNAs hold great promise to expand and transform treatment options for thalassemia in the future by precisely targeting pathogenic molecular networks. Ongoing innovations, such as advancements in miRNA delivery systems, improved targeting mechanisms, and enhanced understanding of miRNA biology, continue to drive progress in this emerging field towards realizing the clinical potential of miRNA-based medicines for thalassemia patients.

BIOM-13. THE MIR-17/92 CO-EXPRESSED NETWORK IS ENRICHED IN AGGRESSIVE PEDIATRIC BRAIN TUMORS

Abstract BACKGROUND Over the past two decades, the understanding of miRNA biology has drastically increased as miRNAs have been found to pervade most aspects of molecular biology–from cellular growth to apoptosis. Nevertheless, there has been little understanding of the role of miRNAs in pediatric brain tumors. In this study, we sought to correlate miRNA expression with pediatric brain tumor histologies. METHODS Weighted gene co-expression network analysis (WGCNA) was performed to determine co-expressed miRNA networks that correlated with distinct brain tumor histologies. Our study cohort consisted of miRNA-sequencing of 262 pediatric brain tumor histologies consisting of Atypical Teratoid/Rhabdoid tumors, Craniopharyngioma, Ependymomas, Ganglioglioma, Low-grade astrocytic tumors, High-grade astrocytic tumors, and Medulloblastoma. We utilized associated multi-omics data from the Open Pediatric Brain Tumor Atlas to validate the results. RESULTS WGCNA analysis revealed a distinct miRNA network consisting of 32 miRNAs with miR-17-5p as the hub miRNA that was markedly upregulated in the aggressive brain tumor group (p<0.001). Interestingly, the majority of the miRNA network consisted of the miR-17/92 family of miRNAs, which are known for their oncogenic role in various cancers. To determine the transcriptional regulatory mechanism of miR-17/92 miRNAs, we first looked at sample-matched RNA-sequencing data. The gene encoding for the miR-17/92 miRNAs, MIR17HG, was significantly overexpressed (p<0.001). Further upstream, we observed that E2F1/2/3, known transcriptional regulators of MIR17HG, gene and protein expressions were significantly overexpressed (p<0.01). Sample-matched phospho-proteomics data indicated the E2F regulator, RB1, being hyperphosphorylated–additionally supporting the E2F activity in these samples. CONCLUSION These findings reveal a network of oncogenic miRNAs consisting of the miR-17/92 family that are distinctly overexpressed in aggressive pediatric brain tumors. Moreover, we suggest that the E2F-RB1 axis is the upstream regulator of the miR-17/92 family of miRNAs.

Genetic Alchemy unveiled: MicroRNA-mediated gene therapy as the Artisan craft in the battlefront against hepatocellular carcinoma-a comprehensive chronicle of strategies and innovations.

Investigating therapeutic miRNAs is a rewarding endeavour for pharmaceutical companies. Since its discovery in 1993, our understanding of miRNA biology has advanced significantly. Numerous studies have emphasised the disruption of miRNA expression in various diseases, making them appealing candidates for innovative therapeutic approaches. Hepatocellular carcinoma (HCC) is a significant malignancy that poses a severe threat to human health, accounting for approximately 70%-85% of all malignant tumours. Currently, the efficacy of several HCC therapies is limited. Alterations in various biomacromolecules during HCC progression and their underlying mechanisms provide a basis for the investigation of novel and effective therapeutic approaches. MicroRNAs, also known as miRNAs, have been identified in the last 20years and significantly impact gene expression and protein translation. This atypical expression pattern is strongly associated with the onset and progression of various malignancies. Gene therapy, a novel form of biological therapy, is a prominent research area. Therefore, miRNAs have been used in the investigation of tumour gene therapy. This review examines the mechanisms of action of miRNAs, explores the correlation between miRNAs and HCC, and investigates the use of miRNAs in HCC gene therapy.

MicroRNAs as promising biomarkers and potential therapeutic agents in breast cancer management: a comprehensive review

Breast cancer (BC), a complex and varied ailment, poses a significant global health burden. MicroRNAs (miRNAs) have emerged as vital regulators in BC progression, with potential implications for diagnosis and treatment. This review aims to synthesize current insights into miRNA dysregulation in BC. MiRNAs, small RNA molecules, govern gene expression post-transcriptionally and are implicated in BC initiation, metastasis, and therapy resistance. Differential expression of specific miRNAs in BC tissues versus normal breast tissue sheds light on underlying molecular mechanisms. MiRNAs also offer promise as diagnostic biomarkers due to their stable nature, accessibility in bodily fluids, and altered expression patterns in early-stage disease, augmenting conventional diagnostic methods. Beyond diagnosis, miRNAs also hold promise as therapeutic targets in BC. By modulating the expression of specific dysregulated miRNAs, it may be possible to restore normal cellular functions and overcome treatment resistance. However, several challenges need to be addressed before miRNA-based therapies can be translated into clinical practice, including the development of efficient delivery systems and rigorous evaluation through preclinical and clinical trials. MiRNAs represent a promising avenue in BC research, offering potential applications in diagnosis, prognosis, and therapeutic interventions. As our understanding of miRNA biology deepens and technology advances, further research and collaborative efforts are needed to fully exploit the diagnostic and therapeutic potential of miRNAs in BC management. Ultimately, the integration of miRNA-based approaches into clinical practice may lead to more personalized and effective strategies for combating this devastating disease.

MiRNA Biology in Chronic Lymphocytic Leukemia

microRNAs (miRNAs) are a class of small non-coding RNAs that play a crucial regulatory role in fundamental biological processes and have been implicated in various diseases, including cancer. The first evidence of the cancer-related function of miRNAs was discovered in chronic lymphocytic leukemia (CLL) in the early 2000s. Alterations in miRNA expression have since been shown to strongly influence the clinical course, prognosis, and response to treatment in patients with CLL. Therefore, the identification of specific miRNA alterations not only enhances our understanding of the molecular mechanisms underlying CLL but also holds promise for the development of novel diagnostic and therapeutic strategies. This review aims to provide a comprehensive summary of the current knowledge and recent insights into miRNA dysregulation in CLL, emphasizing its pivotal roles in disease progression, including the development of the lethal Richter syndrome, and to provide an update on the latest translational research in this field.

Sex-Biased Expression and Response of microRNAs in Neurological Diseases and Neurotrauma.

Neurological diseases and neurotrauma manifest significant sex differences in prevalence, progression, outcome, and therapeutic responses. Genetic predisposition, sex hormones, inflammation, and environmental exposures are among many physiological and pathological factors that impact the sex disparity in neurological diseases. MicroRNAs (miRNAs) are a powerful class of gene expression regulator that are extensively involved in mediating biological pathways. Emerging evidence demonstrates that miRNAs play a crucial role in the sex dimorphism observed in various human diseases, including neurological diseases. Understanding the sex differences in miRNA expression and response is believed to have important implications for assessing the risk of neurological disease, defining therapeutic intervention strategies, and advancing both basic research and clinical investigations. However, there is limited research exploring the extent to which miRNAs contribute to the sex disparities observed in various neurological diseases. Here, we review the current state of knowledge related to the sexual dimorphism in miRNAs in neurological diseases and neurotrauma research. We also discuss how sex chromosomes may contribute to the miRNA sexual dimorphism phenomenon. We attempt to emphasize the significance of sexual dimorphism in miRNA biology in human diseases and to advocate a gender/sex-balanced science.

Identification of MicroRNAs Binding Site in the 3’Untranslated Region of Long Non-Coding RNA, MIR497HG: A Bioinformatic Prediction

Introduction: Prediction and identification of miRNAs target genes are crucial for understanding the biology of miRNAs. Amidst reported long-coding RNA (lncRNA), the microRNA 195-497 cluster host gene (MIR497HG) regulation is mediated by multiple non-coding RNAs (ncRNAs) such as microRNAs (miRNAs). MIR497HG has been implicated as a tumour suppressor in various cancers. However, the impact of MIR497HG and its derived miRNAs is largely unknown and still needs to be further explored. Employing an experimental approach is often challenging since some lncRNAs are difficult to identify and isolate by the current isolation technique. Thus, bioinformatic tools are introduced to aid these problems. This study sought to search and identify the miRNAs targeting the 3’untranslated region (3’UTR) of MIR497HG. Methods: Here, bioinformatic tools were adopted to identify a unique list of miRNAs that potentially target the 3’UTR of MIR497HG. Results: A total of 57 candidate miRNAs that target the 3’UTR of MIR497HG were extracted using the miRDB. Meanwhile, STarMir predicted 291 miRNAs that potentially target the 3’UTR of MIR497HG. A common list of 36 miRNAs was obtained using the Venny 2.1.0 and further narrowed down using the LogitProb score of StarMir. Finally, a total 4 miRNAs (hsa-miR-3182, hsa-miR-7156-5p, hsa-miR-452-3p and hsa-miR-2117) were identified. The mRNA target of identified miRNAs was identified by TargetScan. Finally, Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of mRNA target was done using Enrichr. Conclusion: This finding could be useful in understanding the complex interaction between MIR497HG and its regulatory miRNA. In addition, a comparative analysis of computational miRNA-target predictions is provided in this study would potentially lay the foundations for miRNAs to be used for biomarkers in cancer research.

Exosome-Derived microRNA: Potential Target for Diagnosis and Treatment of Sepsis.

Exosome-derived microRNAs (miRNAs) are emerging as pivotal players in the pathophysiology of sepsis, representing a new frontier in both the diagnosis and treatment of this complex condition. Sepsis, a severe systemic response to infection, involves intricate immune and nonimmune mechanisms, where exosome-mediated communication can significantly influence disease progression and outcomes. During the progress of sepsis, the miRNA profile of exosomes undergoes notable alterations, is reflecting, and may affect the progression of the disease. This review comprehensively explores the biology of exosome-derived miRNAs, which originate from both immune cells (such as macrophages and dendritic cells) and nonimmune cells (such as endothelial and epithelial cells) and play a dynamic role in modulating pathways that affect the course of sepsis, including those related to inflammation, immune response, cell survival, and apoptosis. Taking into account these dynamic changes, we further discuss the potential of exosome-derived miRNAs as biomarkers for the early detection and prognosis of sepsis and advantages over traditional biomarkers due to their stability and specificity. Furthermore, this review evaluates exosome-based therapeutic miRNA delivery systems in sepsis, which may pave the way for targeted modulation of the septic response and personalized treatment options.

MiRNA-Based Technologies in Cancer Therapy.

The discovery of therapeutic miRNAs is one of the most exciting challenges for pharmaceutical companies. Since the first miRNA was discovered in 1993, our knowledge of miRNA biology has grown considerably. Many studies have demonstrated that miRNA expression is dysregulated in many diseases, making them appealing tools for novel therapeutic approaches. This review aims to discuss miRNA biogenesis and function, as well as highlight strategies for delivering miRNA agents, presenting viral, non-viral, and exosomic delivery as therapeutic approaches for different cancer types. We also consider the therapeutic role of microRNA-mediated drug repurposing in cancer therapy.

Near-Infrared Fluorescence Imaging of miRNA Using a Transmembrane Polypeptide-Based Genetic Reporter.

MicroRNAs (miRNAs) are small noncoding RNAs that play important regulatory roles in multiple biological processes. Many miRNAs exhibit unique expression patterns and are considered as theranostic biomarkers in a variety of human diseases. A reporter system that is capable of imaging miRNA in vivo is crucial for investigating miRNA biology. In the present study, an organic anion-transporting polypeptide 1B3 (OATP1B3)-based genetic switch system is designed and optimized to achieve near-infrared fluorescent imaging of miRNA by the uptake of indocyanine green (ICG) dye. The reporter system, named miR-ON-OB3, is shown to be efficient to regulate the expression of OATP1B3 in mammalian cells. Notably, the results indicate that the system is of high sensitivity for near-infrared fluorescence imaging of both exogenous and endogenous miRNA in mammalian cells. Moreover, the system is proved to be functional for real-time near-infrared fluorescence imaging of miRNA in living mice. This study establishes a novel genetic encoded reporter for near-infrared fluorescence imaging of miRNA, which may provide a potential tool for in vivo imaging of miRNA in clinical applications due to the clinical availability of ICG.

Circulating and extracellular vesicle-derived microRNAs as biomarkers in bone-related diseases.

MicroRNAs (miRNA) are small non-coding RNA molecules that regulate posttranscriptional gene expression by repressing messengerRNA-targets. MiRNAs are abundant in many cell types and are secreted into extracellular fluids, protected from degradation by packaging in extracellular vesicles. These circulating miRNAs are easily accessible, disease-specific and sensitive to small changes, which makes them ideal biomarkers for diagnostic, prognostic, predictive or monitoring purposes. Specific miRNA signatures can be reflective of disease status and development or indicators of poor treatment response. This is especially important in malignant diseases, as the ease of accessibility of circulating miRNAs circumvents the need for invasive tissue biopsy. In osteogenesis, miRNAs can act either osteo-enhancing or osteo-repressing by targeting key transcription factors and signaling pathways. This review highlights the role of circulating and extracellular vesicle-derived miRNAs as biomarkers in bone-related diseases, with a specific focus on osteoporosis and osteosarcoma. To this end, a comprehensive literature search has been performed. The first part of the review discusses the history and biology of miRNAs, followed by a description of different types of biomarkers and an update of the current knowledge of miRNAs as biomarkers in bone related diseases. Finally, limitations of miRNAs biomarker research and future perspectives will be presented.

Extrachromosomal circular MiR-17-92 amplicon promotes HCC.

Extrachromosomal circular DNAs (eccDNAs) are prevalent in cancer genomes and emerge as a class of crucial yet less characterized oncogenic drivers. However, the structure, composition, genome-wide frequency, and contribution of eccDNAs in HCC, one of the most fatal and prevalent cancers, remain unexplored. In this study, we provide a comprehensive characterization of eccDNAs in human HCC and demonstrate an oncogenic role of microRNA (miRNA)-17-92-containing eccDNAs in tumor progression. Using the circle-sequencing method, we identify and characterize more than 230,000 eccDNAs from 4 paired samples of HCC tumor and adjacent nontumor liver tissues. EccDNAs are highly enriched in HCC tumors, preferentially originate from certain chromosomal hotspots, and are correlated with differential gene expression. Particularly, a series of eccDNAs carrying the miRNA-17-92 cluster are validated by outward PCR and Sanger sequencing. Quantitative PCR analyses reveal that miRNA-17-92-containing eccDNAs, along with the expression of their corresponding miRNAs, are elevated in HCC tumors and associated with poor outcomes and the age of HCC patients. More intriguingly, exogenous expression of artificial DNA circles harboring the miR-17-92 cluster, which is synthesized by the ligase-assisted minicircle accumulation method, can significantly accelerate HCC cell proliferation and migration. These findings delineate the genome-wide eccDNAs profiling of HCC and highlight the functional significance of miRNA-containing eccDNAs in tumorigenesis, providing insight into HCC pathogenesis and cancer therapy, as well as eccDNA and miRNA biology.

Targeting miRNAs and Other Non-Coding RNAs as a Therapeutic Approach: An Update.

Since the discovery of the first microRNAs (miRNAs, miRs), the understanding of miRNA biology has expanded substantially. miRNAs are involved and described as master regulators of the major hallmarks of cancer, including cell differentiation, proliferation, survival, the cell cycle, invasion, and metastasis. Experimental data indicate that cancer phenotypes can be modified by targeting miRNA expression, and because miRNAs act as tumor suppressors or oncogenes (oncomiRs), they have emerged as attractive tools and, more importantly, as a new class of targets for drug development in cancer therapeutics. With the use of miRNA mimics or molecules targeting miRNAs (i.e., small-molecule inhibitors such as anti-miRS), these therapeutics have shown promise in preclinical settings. Some miRNA-targeted therapeutics have been extended to clinical development, such as the mimic of miRNA-34 for treating cancer. Here, we discuss insights into the role of miRNAs and other non-coding RNAs in tumorigenesis and resistance and summarize some recent successful systemic delivery approaches and recent developments in miRNAs as targets for anticancer drug development. Furthermore, we provide a comprehensive overview of mimics and inhibitors that are in clinical trials and finally a list of clinical trials based on miRNAs.

Abstract 6686: Tumor suppressor miRNA-665 based serum biomarker for detecting pancreatobiliary cancer

Abstract Background: MicroRNA-665 (miR-665), an intracellular inhibitor of pancreatic cancer (PC) cells, might be a potential biomarker to detect pancreatobiliary cancer (PBca). We sought to determine the diagnostic ability of miR-665 as a serum biomarker for PBca, and to explore the role of miR-665 in PC. Methods: This multicenter study enrolled patients with treatment-naïve PBca and healthy participants. PBca-related serum miRNAs were determined using weighted co-expression network analysis of a comprehensive serum miRNA microarray dataset in an exploratory cohort. Using various combinations of PBca-related serum miRNAs, Fisher’s linear discriminant analyses provided miRNA signatures to discriminate PBca from healthy controls. MiRNA signatures with a sensitivity/specificity (SN/SP) of ≥80/80% and high AUC in comparison with the AUC of CA19-9 were defined as the diagnostic miRNA signature in exploratory, validation and independent validation cohorts, whose accuracy was confirmed by 5-fold cross validation. Biology of the diagnostic miRNAs was evaluated using biopsy samples from liver metastasis of PC patients and human PC cells. Results: We analyzed 496 of 1487 enrolled subjects (150 healthy and 134 PBca, 50 healthy and 47 PBca, and 50 healthy and 46 PBca subjects in the exploratory, validation and independent validation cohorts, respectively). Among miRNA signatures from 82 PBca-related miRNAs, a five serum miRNA combination containing miR-665 was identified as the diagnostic miRNA signature in all three cohorts. SN/SP and AUC in the validation and independent validation cohorts were 92/88% and 0.95 (CA19-9: 81/92% and 0.94) and 87/80% and 0.91 (CA19-9: 80/98% and 0.87), respectively. In sub-population analysis for detecting 48 resectable PCs, the discriminative ability of the diagnostic miRNA signature plus CA19-9 (SN/SP: 90/78%) was superior in sensitivity to that of CA19-9 alone (60/94%). In seven PC patients with liver metastasis, high expression of intratumor miR-665 tended to correlate with high serum miR-665 level (r = 0.56) and low expression of intratumor phospho-Erk expression (r = 0.57). Transfection of miR-665 to a human PC cell led to cell growth suppression. Conclusions: This study identified the diagnostic ability of a tumor suppressor miR-665-based serum miRNA signature for PBca. For detecting resectable PC, a miR-665-based serum miRNA signature plus CA19-9 is a superior biomarker to CA19-9 alone. Citation Format: Shuichi Mitsunaga, Makoto Ueno, Masahiro Tsuda, Takamichi Kuwahara, Yukiko Takayama, Keiji Hanada, Hitoshi Yoshida, Kenji Takahashi, Kohei Nakata, Hideaki Iwama, Masafumi Ikeda, Satoshi Kobayashi, Ikuya Miki, Kazuo Hara, Ryota Higuchi, Akinori Shimizu, Tomohiro Nomoto, Hidetaka Iwamoto, Masafumi Nakamura, Etsuro Hatano, Hiroko Sudo, Satoko Takizawa, Atsushi Ochiai. Tumor suppressor miRNA-665 based serum biomarker for detecting pancreatobiliary cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6686.

Harnessing PUF-Based Reporters for Noninvasive Imaging of the MicroRNA Dynamics in Differentiation.

Precise characterization of miRNA expression patterns is critical to exploit the complexity of miRNA regulation in biology. Herein, we developed a Pumilio/FBF (PUF) protein-based engineering luciferase reporter system, PUF/miR, to quantitatively and non-invasively sense miRNA activity in living cells and animal models. We verified the feasibility of this reporter by monitoring the expression of several types of miRNAs (miRNA-9, 124a, 1, and 133a) in neural and muscle differentiated cells as well as subcutaneous or tibial anterior muscles in mice. The quantitative RT-PCR also validated the reliability and quantitative consistency of bioluminescence imaging in detecting miRNA expression. We further effectively employed this reporter system to visualize the expression of miRNA-1 and miRNA-133a in mouse models of skeletal muscle injury. As a non-invasive and convenient innovative approach, our results have realized the positive bioluminescence imaging of endogenous miRNAs in vitro and in vivo using the PUF/miR system. We believe that this approach would provide a potential means for noninvasive monitoring of disease-related miRNAs and could facilitate a deeper understanding of miRNA biology.