Molecular biology. A circuitous route to noncoding RNA

MVGNCDA: Identifying Potential circRNA-Disease Associations Based on Multi-view Graph Convolutional Networks and Network Embeddings

Increasing evidences have indicated that circular RNAs play a crucial role in the onset and progression of various diseases. However, exploring potential disease-associated circRNAs using conventional experimental techniques remains both time-intensive and costly. Recently, various computational approaches have been developed to detect the circRNA-disease associations. Nevertheless, due to the sparsity of the data and the inefficient utilization of similarity representation, it is still a challenge to effectively detect unknown circRNA-disease associations using multisource data. In this work, we propose an innovative computational framework, MVGNCDA, which merges a multi-view graph convolutional network (GCN) and biased random walk-based network embeddings to evaluate potential circRNA-disease associations from multisource data. First, we calculate disease semantic similarity, circRNA functional similarity, and their Gaussian interaction profile (GIP) kernel and cosine similarity. MVGNCDA utilizes multi-view GCNs to extract local node embeddings of diseases and circRNAs in the context of multisource information. Then, we construct a heterogeneous network utilizing integrated similarity and verified circRNA-disease associations, which is subsequently used to learn global node embeddings. Furthermore, the final fused local and global node embeddings are decoded to evaluate the circRNA-disease associations using a bilinear decoder. The fivefold cross-validation results demonstrate that MVGNCDA outperforms existing methods across five public datasets. Moreover, case study also confirms that MVGNCDA is capable of efficiently identifying unknown circRNA-disease associations.

Non-coding RNAs in plant stress responses: molecular insights and agricultural applications

Non-coding RNAs (ncRNAs) have emerged as crucial regulators in plant responses to environmental stress, orchestrating complex networks that finetune gene expression under both abiotic and biotic challenges. To elucidate this intricate ncRNA crosstalk, this review comprehensively summarizes recent advances in understanding the mechanisms of key regulatory ncRNAs including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), tRNA derived fragments (tRFs) and small interfering RNAs (siRNAs) in mediating plant adaptations to stress conditions. We discuss molecular insights into how these ncRNAs modulate stress signalling pathways, control hormonal responses and interact through elaborate crosstalk mechanisms. We also emphasize emerging biotechnological strategies that leverage both innate and artificial ncRNAs as well as potential approaches for finetuning ncRNA levels to engineer stress-resilient crops. Collectively, continued advances in high-throughput sequencing, functional genomics and computational modelling will deepen our understanding of ncRNA network mediated stress responses, ultimately guiding the design of robust climate-resilient crops.

CircZMYM2 Alleviates TGF-β1-Induced Proliferation, Migration and Activation of Fibroblasts via Targeting miR-199b-5p/KLF13 Axis

Dysregulated circular RNAs (circRNAs) has been revealed to be involved in pulmonary fibrosis progression. Herein, this study focused on exploring the function and mechanism of circRNA Zinc Finger MYM-Type Containing 2 (circZMYM2) on idiopathic pulmonary fibrosis (IPF) using transforming growth factor (TGF)-β1-stimulated fibroblasts. Human fibroblast cell lines IMR-90 and HFL1 were stimulated with TGF-β1 to mimic fibrosis condition in vitro. Levels of genes and proteins were detected by qRT-PCR and western blotting. Cell proliferation and migration were analyzed using cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine (EdU) and wound healing assays. The fibrosis progression was determined by the change of E-cadherin, α-smooth muscle actin (α-SMA), collagen type I α 1 (COL1A1) and collagen type III α 1 (COL3A1). The interaction between miR-199b-5p and circZMYM2 or KLF13 (Kruppel Like Factor 13) was analyzed using dual-luciferase reporter, RIP and RNA-pull-down assays. CircZMYM2 was decreased in TGF-β1-induced IMR-90 and HFL1 fibroblasts. Functionally, re-expression of circZMYM2 in IMR-90 and HFL1 cells could attenuate TGF-β1-evoked proliferation, migration and fibrosis in cells. Mechanistically, the circZMYM2/miR-199b-5p/KLF13 constituted a competing endogenous RNA (ceRNA). TGF-β1 reduced KLF13 expression and increased miR-199b-5p expression in IMR-90 and HFL1 cells. Further rescue experiments suggested that miR-199b-5p up-regulation or KLF13 knockdown reversed the anti-fibrotic effects of circZMYM2; moreover, silencing of miR-199b-5p exhibited anti-fibrotic effects, which was counteracted by KLF13 knockdown. CircZMYM2 had an anti-fibrotic effect that could suppress fibroblast activation via miR-199b-5p/KLF13 axis, pointing a novel perspective into the potential action pattern of circ_0022383 in IPF.

Plasmodium Infection Modulates Host Inflammatory Response through circRNAs during the Intracellular Stage in Red Blood Cells

The integration of RNA- and DNA-based assays enables the investigation of disease dynamics, specifically assessing the role of asymptomatic or subclinical infections in malaria transmission. Circular RNAs (circRNAs), a distinct category of noncoding RNAs, are implicated in numerous pathogenic mechanisms. As of now, research has yet to explore circRNAs' function in malaria infection. The findings revealed that Plasmodium infection upregulated 60 circRNAs and downregulated 71 in BALB/c mice. We selected 11 differentially expressed (DE) circRNAs according to function prediction of target miRNA-mRNA and coding protein, and these were further confirmed by validation experiments. IRESfinder, GO, and KEGG evaluations indicated that 7 DE circRNAs possess protein-coding potential and are enriched in the MAPK signaling cascade. In P.y17XL-infected BALB/c mouse models, the findings substantiated that the dynamic characteristics of DE circRNAs correlated with inflammation, and the MAPK and NF-κB signaling cascades were activated, also contributing to the inflammatory reaction during malaria infection. This study establishes Plasmodium-induced circRNA expression as a novel mechanism by which the parasite modulates host immune signaling, advancing the understanding of Plasmodium-host cell interactions. In addition, 42 circRNAs were found in normal BALB/c mice, and 25 circRNAs were discovered in P.y17XL-infected BALB/c mice, excluding 1238 circRNAs shared by normal and P.y17XL-infected BALB/c mice. Plasmodium infection changes the expression profile of circRNAs in the host, and these altered circRNAs are involved in the inflammatory response during malaria infection. In addition, Plasmodium possibly regulates the reverse splicing of pre-mRNA or m6A modification of RNA, inducing the production of novel circRNAs in the host.

Circular RNA in liver cancer research: biogenesis, functions, and roles

Liver cancer, characterized by its insidious nature, aggressive invasiveness, and propensity for metastasis, has witnessed a sustained increase in both incidence and mortality rates in recent years, underscoring the urgent need for innovative diagnostic and therapeutic approaches. Emerging research indicates that CircRNAs (circular RNAs) are abundantly and stably present within cells, with their expression levels closely associated with the progression of various malignancies, including hepatocellular carcinoma. In the context of liver cancer progression, circRNAs exhibit promising potential as highly sensitive diagnostic biomarkers, offering novel avenues for early detection, and also function as pivotal regulatory factors within the carcinogenic process. This study endeavors to elucidate the biogenesis, functional roles, and underlying mechanisms of circRNAs in hepatocellular carcinoma, thereby providing a fresh perspective on the pathogenesis of liver cancer and laying a robust foundation for the development of more precise and effective early diagnostic tools and therapeutic strategies.

Circular RNA circCLASP2 promotes nasopharyngeal carcinoma progression through binding to DHX9 to enhance PCMT1 translation

BACKGROUND

Circular RNAs (circRNAs), characterized by their covalently closed-loop structures, constitute a distinct class of non-coding RNAs. They play pivotal regulatory roles within cells and are intricately associated with the progression of malignant tumors. However, their roles and the underlying mechanisms in nasopharyngeal carcinoma (NPC) progression have yet to be fully uncovered and comprehensively understood.

METHODS

Employing RNA sequencing technology, high-abundance circular RNAs in NPC were identified. Expression analysis of circCLASP2 in NPC tissues was conducted using quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization experiments. Through in vitro and in vivo functional assays, the influence of circCLASP2 on the proliferation and metastasis of NPC was investigated. LC-MS/MS technology analyzed the binding partners of circCLASP2, its differentially regulated targets, and the associated proteins of PCMT1. Interactions among circCLASP2, DHX9 protein, and PCMT1 mRNA were elucidated through RNA immunoprecipitation and RNA pull-down techniques. The effects of circCLASP2 and DHX9 on RNA G-quadruplex (rG4) structures and PCMT1 mRNA translation were explored through immunofluorescence (IF), ribosomal gradient separation, and dual-luciferase reporter assays. Immunoprecipitation (IP) revealed the downstream effector of the circCLASP2-DHX9-PCMT1 regulatory axis and Phalloidin staining confirmed its ultimate effect on the cytoskeleton. PDS treatment was applied for interventions in NPC, demonstrating potential therapeutic avenues.

RESULTS

Our research revealed that circCLASP2, a novel circRNA that has not been reported in tumors, is upregulated in NPC and fosters cell proliferation and metastasis both in vitro and in vivo. Mechanistically, circCLASP2 acts as a molecular scaffold, facilitating the approximation of DHX9 to PCMT1 mRNA. DHX9 unwinds the inhibitory rG4 structure near the translation initiation site on PCMT1 mRNA, increasing PCMT1 expression. PCMT1 binds to and upregulates cytoskeleton-associated proteins, modulating cytoskeleton strength and dynamics and ultimately driving NPC cell proliferation and metastasis. In both in vitro and in vivo experiments, PDS significantly inhibits NPC growth and metastasis, showcasing promising therapeutic potential.

CONCLUSIONS

Our investigation pinpointed a circular RNA, circCLASP2, which is upregulated in NPC and augments cytoskeletal functions via the DHX9-PCMT1 axis, contributing to the malignancy progression of NPC. This pathway holds promise as a potential therapeutic target for NPC. Furthermore, these molecules could also serve as biomarkers for adjunct diagnosis and prognosis assessment in NPC.

CircMETTL6 Suppresses Ovarian Cancer Cell Growth and Metastasis Through Inhibition of GDF15 Transcription by Disrupting the NONO-POLR2A Complex

Circular RNAs (circRNAs) are a distinctive class of non-coding RNAs with covalent closed-loop structure, lacking 5' caps and 3' poly(A) tails. These molecules are prevalent in eukaryotes and play key roles in cancer. Here, the function of a new circRNA, circMETTL6, in ovarian cancer is identified and investigated. The prognostic significance of circMETTL6 is assessed using RNA in situ hybridization. Functional studies involving circMETTL6 overexpression are performed both in vitro and in vivo. Mechanistic investigations are performed using RNA-seq, RNA pull-down, RNA immunoprecipitation, co-immunoprecipitation, chromatin immunoprecipitation, protein degradation assay and dual-luciferase reporter assays. circMETTL6 is significantly downregulated in ovarian cancer, and its lower expression correlates with worse prognosis. Overexpression of circMETTL6 significantly inhibited proliferation, migration, and invasion of ovarian cancer cell in vitro, as well as tumor growth and metastasis in vivo. Mechanistically, circMETTL6 recruited the non-POU domain containing octamer binding protein (NONO) by binding to its Coiled-coil domain and disrupted its binding with RNA polymerase II subunit A (POLR2A), and consequently inhibiting growth differentiation factor 15 (GDF15) transcription, thereby suppressing ovarian cancer progression. These findings establish circMETTL6 as a novel tumor suppressor in ovarian cancer. Targeting the circMETTL6/NONO/GDF15 axis presents a potential therapeutic avenue for ovarian cancer treatment.

Genome-wide characterization of circular RNAs in three rat models of pulmonary hypertension reveals distinct pathological patterns

BACKGROUND

Pulmonary hypertension (PH) is a devastating disease marked by elevated pulmonary artery pressure, resulting in right ventricular (RV) failure and mortality. Despite the identification of several dysregulated genes in PH, the involvement of circular RNAs (circRNAs), a subset of long noncoding RNAs, remains largely unknown.

METHODS

In this study, high-throughput RNA sequencing was performed to analyze the genome-wide expression patterns of circRNAs in pulmonary arteries from three models of PH rats induced by hypoxia (Hyp), hypoxia/Sugen5416 (HySu), and monocrotaline (MCT). Differentially expressed circRNAs (DEcircRNAs) were identified, and a weighted gene coexpression network was constructed to explore circRNA networks associated with PH pathogenesis. A circRNA-miRNA-mRNA regulatory network was built, and the functional significance of targeted mRNAs was evaluated. Single-cell RNA sequencing provided insights into the distribution of cell type-specific circRNAs across PH progression.

RESULTS

Our analysis revealed 45 circRNAs exhibiting significant changes across all three PH rat models, with their host genes participating in the calcium signaling and muscle contraction. We identified 372 PH-related circRNA-miRNA-mRNA interactions, shedding light on the regulatory networks during PH development. Furthermore, we uncovered 186, 195 and 311 Hyp-, Hysu- and MCT-specific circRNAs, respectively. These circRNAs were enriched in distinct biological processes, emphasizing their unique regulatory roles. Single-cell spatial distribution analysis of these circRNAs in the pulmonary arteries of PH patients revealed that Hyp-specific circRNA predominantly appeared in the pulmonary vascular structural cells, while HySu- and MCT-specific circRNAs exhibited broader distribution, including significant enrichment in immune-related cells.

CONCLUSION

Our study presents the first comprehensive view of circRNA regulatory networks in the pulmonary arteries of three PH rat models. We provide insights into PH-associated circRNAs, particularly their involvement in calcium signaling and muscle contraction.

Has_circ_ASH1L acts as a sponge for miR-1254 to promote the malignant progression of cervical cancer by targeting CD36

Cervical cancer (CC) is a prevalent gynecological malignancy. Increasing evidence suggests that circular RNAs (circRNAs) play a pivotal role in the pathogenesis of CC. However, the regulatory function of circ_ASH1L in CC remains elusive. In this study, we aim to elucidate the precise role and underlying mechanism of circ_ASH1L in the malignant progression of CC. The human CC dataset GSE102686 was extracted from the Gene Expression Omnibus (GEO) database for the analysis of differentially expressed circRNAs. Target gene prediction softwares were utilized to predict the binding of miRNAs to circ_ASH1L sponge. The expression level of circ_ASH1L in CC tissues and cells was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The characteristics of circ_ASH1L were determined by RNase R digestion, actinomycin D, and nucleo-plasmic separation assays. The effects of circ_ASH1L, miR-1254, and CD36 gain-and-loss on the malignant progression of CC were investigated using Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, wound scratch, transwell, and Western blot assay. The effect of circ_ASH1L on tumorigenicity of CC cells in vivo was evaluated in nude mice through tumor xenograft assay. The targeted regulatory relationship between circ_ASH1L/miR-1254 as well as miR-1254/CD36 was validated by dual-luciferase reporter assay. We screened the differentially expressed circ_ASH1L from the GEO dataset GSE102686 and confirmed its circular structure. Furthermore, we observed a significant upregulation of circ_ASH1L in both CC tissues and cells. Overexpression of circ_ASH1L promotes proliferation, invasion, and migration of CC cells while inhibiting cell apoptosis. However, silencing circ_ASH1L showed opposite results and inhibited tumorigenicity of CC cells in nude mice. Furthermore, we have identified circ_ASH1L as a miR-1254 sponge in CC cells. Notably, our in vitro experiments demonstrated that exogenously modulating the expression of miR-1254 effectively counteracted the impact of circ_ASH1L on the malignant phenotypic characteristics of CC cells. Similarly, modulation of CD36 expression efficiently counteracted the effect of miR-1254 on the malignant biological behavior of CC cells. In conclusion, circ_ASH1L promoted the malignant progression of CC via upregulating CD36 expression through sponging miR-1254.

Circular RNAs as Biomarkers in Breast Cancer Diagnosis, Prognosis, Molecular Types, Metastasis and Drug Resistance

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide. Circular RNAs (circRNAs), a novel class of endogenous noncoding RNA with a covalently closed continuous loop that lacks the 5'-cap structure and the 3'-poly A tail, are more stable than linear RNAs and less susceptible to degradation by nucleases. CircRNAs are widespread in multiple mammalian genomes and have been detected in various tissues, cells and body fluids. Increasing evidence shows that abnormal expression of circRNAs is involved in the development of a variety of diseases, including breast cancer. Numerous studies have explored the potential of circRNAs as biomarkers in various malignant tumors. In this review, we aim to provide a comprehensive overview of the latest advances in circRNAs as promising biomarkers in the early diagnosis, prognosis, molecular type, metastasis and drug resistance of breast cancer.

Hsa_circ_0001278 Facilitates Colorectal Cancer Progression via Sponging miR-338-5p and Regulating AMOTL1 Expression

BACKGROUND

Colorectal cancer (CRC) ranks as the third most common cancer and is second in terms of mortality worldwide. Circular RNAs are involved in the occurrence and development of malignant tumors by functioning either as oncogenes or tumor suppressors.

METHOD

This study investigated the functions of hsa_circ_0001278 in CRC. We analyzed the expression of hsa_circ_0001278 in CRC tissues and adjacent normal tissues. In order to understand the roles of hsa_circ_0001278 in CRC in terms of cellular biological behavior, in vitro experiments were conducted. A mechanistic study was designed to investigate the regulatory effect of hsa_circ_0001278 on CRC.

RESULTS

Hsa_circ_0001278 was found to be significantly upregulated in CRC specimens. The functional analysis indicated that hsa_circ_0001278 promotes aggressive phenotypes of CRC cells. Further mechanistic studies revealed that hsa_circ_0001278 sponges miR-338-5p to regulate angiomotin-like 1 (AMOTL1), thereby facilitating CRC progression.

CONCLUSION

Our results demonstrate that hsa_circ_0001278 promotes malignant behaviors in CRC cells by sponging miR-338-5p to regulate AMOTL1 expression. This suggests that hsa_circ_0001278 may serve as a novel target for CRC treatment.

Hsa_circ_0043533 modulates apoptosis and viability of granulosa cells via miR-409-3p/BCL2 and EMT signalling in PCOS: Providing novel perspective of metformin

Polycystic ovary syndrome (PCOS) represents a significant cause of infertility among women of reproductive age. Studies have established a close association between granulosa cells (GCs) and the abnormal follicle formation and ovulation processes characteristic of PCOS. The interactions among hsa_circ_0043533, miR-409-3p, and BCL2 were verified through luciferase activity assays. In PCOS patients, granulosa cells exhibit notably reduced apoptosis but enhanced growth, leading to their accumulation and the development of polycystic ovaries. The involvement of non-coding RNAs in PCOS has been documented, with elevated levels of hsa_circ_0043533 observed in this condition. A comprehensive series of experiments were conducted to explore the role of hsa_circ_0043533 in PCOS and elucidate its underlying mechanisms. Silencing hsa_circ_0043533 was found to promote apoptosis and hinder the migration, proliferation, and viability of KGN cells. Furthermore, we uncovered the regulatory effects of hsa_circ_0043533 on the miR-409-3p/BCL2 axis and key markers of Epithelial-Mesenchymal Transition (EMT). Additionally, it was observed that metformin modulates the hsa_circ_0043533/miR-409-3p/BCL2 axis. Overall, this study provides novel insights into the molecular mechanisms regulating granulosa cell proliferation and apoptosis in PCOS, further elucidating the molecular pathogenesis of this condition.

Noncoding RNA, friend or foe for nephrolithiasis?

Nephrolithiasis is one of the most common diseases in urology, characterized by notable incidence and recurrence rates, leading to significant morbidity and financial burden. Despite its prevalence, the precise mechanisms underlying stone formation remain incompletely understood, thus hindering significant advancements in kidney stone management over the past three decades. Investigating the pivotal biological molecules that govern stone formation has consistently been a challenging and high-priority task. A significant portion of mammalian genomes are transcribed into noncoding RNAs (ncRNAs), which have the ability to modulate gene expression and disease progression. They are thus emerging as a novel target class for diagnostics and pharmaceutical exploration. In recent years, the role of ncRNAs in stone formation has attracted burgeoning attention. They have been found to influence stone formation by regulating ion transportation, oxidative stress injury, inflammation, osteoblastic transformation, autophagy, and pyroptosis. These findings contributes new perspectives on the pathogenesis of nephrolithiasis. To enhance our understanding of the diagnostic and therapeutic potential of nephrolithiasis-associated ncRNAs, we summarized the expression profiles, biological functions, and clinical significance of these ncRNAs in the current review.

Circular RNA circ_0022707 impedes the progression of preeclampsia via the miR-3135b/GHR/PI3K/Akt axis

Preeclampsia (PE) is a severe pregnancy complication linked to maternal and fetal health, yet its underlying causes and pathogenesis remain elusive. Circular RNA (circRNA), a form of non-coding RNA, is implicated in the progression of PE; nevertheless, the specific mechanism is not fully elucidated. This study aimed to identify and validate circRNAs that are pivotal in the pathophysiology of PE. Firstly, we constructed a ceRNA network using datasets from the GEO database and identified circ_0022707 as our study target. Then, using qRT-PCR analysis, we validated that circ_0022707 was downregulated in preeclamptic placentas compared to those of normal pregnant women. In situ hybridization assays revealed that circ_0022707 existed in placental villous trophoblast cells. Additionally, Pearson correlation analysis revealed a negative relationship between the expression of circ_0022707 and PE-related indicators (systolic and diastolic blood pressure, along with 24-h proteinuria levels). Furthermore, gain-of-function experiments confirmed that circ_0022707 could promote trophoblast cell proliferation and cell cycle progression while suppressing apoptosis. In vivo experiments using a preeclampsia-like mouse model also demonstrated that circ_0022707 administration could mitigate preeclampsia-like symptoms. Mechanistically, we confirmed that circ_0022707 functions through the miR-3135b/GHR/PI3K/Akt pathway in trophoblast cells. Overall, our study has provided insight into the important function of circ_002707 in the development of PE, enhancing our understanding of the disease's mechanism and proposing a viable therapeutic strategy for PE.

Emerging roles of noncoding RNAs in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic lung disease with limited treatment options and efficacy. Evidence suggests that IPF arises from genetic, environmental, and aging-related factors. The pathogenic mechanisms of IPF primarily involve dysregulated repeated microinjuries to epithelial cells, abnormal fibroblast/myofibroblast activation, and extracellular matrix (ECM) deposition, but thus far, the exact etiology remains unclear. Noncoding RNAs (ncRNAs) play regulatory roles in various biological processes and have been implicated in the pathophysiology of multiple fibrotic diseases, including IPF. This review summarizes the roles of ncRNAs in the pathogenesis of IPF and their potential as diagnostic and therapeutic targets.

Hsa-circ-ACSL1 Enhances Apoptosis and Autophagy in Myocarditis Cardiomyocytes Through the miR-7-5p/XBP1 Axis

BACKGROUND

Viral myocarditis (VMC) is a common cardiovascular disease, and circular RNAs (circRNAs) have been identified to play an important role in the pathophysiology of cardiovascular disease. However, the clinical significance, biological functions, and regulatory mechanisms of circRNAs in VMC remain poorly understood. Therefore, this study explored the biological functions and regulatory mechanisms of circ-ACSL1 in VMC.

METHODS

The animal and cell models of VMC were established by infecting BABL/C mice and interleukin-2 cells with coxsackievirus B3 (CVB3). Pro-inflammatory factors, markers of myocardial injury, apoptosis, and autophagy were detected to evaluate the degree of myocardial inflammation and myocardial injury after altering circ-ACSL1, microRNA-7-5p (miR-7-5p), and X-box binding protein 1 (XBP1) expression alone or in combination.

RESULTS

Knocking down circ-ACSL1 could inhibit inflammation, autophagy, and apoptosis in VMC animals and cells. Mechanistically, circ-ACSL1 targeted miR-7-5p to regulate the downstream target XBP1. In addition, depleting miR-7-5p rescued the therapeutic effect of depleting circ-ACSL1. Overexpression of circ-ACSL1 aggravated VMC; however, this effect was saved by knocking down XBP1.

CONCLUSION

By competitively absorbing miR-7-5p, circ-ACSL1 increases XBP1 expression and aggravates myocardial inflammation. Meaningfully, VMC treatment may benefit from circ-ACSL1 as a potential biomarker for precise diagnosis and as a potential therapeutic target.

Biomarkers and diagnostic significance of non-coding RNAs in extracellular vesicles of pathologic pregnancy

Intercellular communication is an important mechanism for the development and maintenance of normal biological processes in all organs, including the female reproductive system. Extracellular vesicles, as important carriers of intercellular communication, contain a variety of biologically active molecules, such as mRNAs, miRNAs, lncRNAs, and circRNAs, which are involved in cell-to-cell exchanges as well as in many physiological and pathological processes in the body. Compared with biomarkers found in tissues or body fluids, extracellular vesicles show better stability due to the presence of their envelope membrane which prevents the degradation of the RNA message in their vesicles. Therefore, the genomic and proteomic information contained in extracellular vesicles can serve as important markers and potential therapeutic targets for female reproductive system-related diseases or placental function. Moreover, changes in the expression of non-coding RNAs (mainly miRNAs, lncRNAs, and circRNAs) in maternal extracellular vesicles can accurately and promptly reflect the progress of female reproductive system diseases. The aim of this review is to collect information on different types of non-coding RNAs with key molecular carriers in female pathologic pregnancies (preeclampsia and recurrent spontaneous abortion), so as to explore the relevant molecular mechanisms in female pathologic pregnancies and provide a theoretical basis for clinical research on the pathogenesis and therapeutic approaches of reproductive system diseases. The current state of the art of exosome isolation and extraction is also summarized.

MicroRNA-155 and its exosomal form: Small pieces in the gastrointestinal cancers puzzle

Gastrointestinal (GI) cancers are common cancers that are responsible for a large portion of global cancer fatalities. Due to this, there is a pressing need for innovative strategies to identify and treat GI cancers. MicroRNAs (miRNAs) are short ncRNAs that can be considered either cancer-causing or tumor-inhibiting molecules. MicroRNA-155, also known as miR-155, is a vital regulator in various cancer types. This miRNA has a carcinogenic role in a variety of gastrointestinal cancers, including pancreatic, colon, and gastric cancers. Since the abnormal production of miR-155 has been detected in various malignancies and has a correlation with increased mortality, it is a promising target for future therapeutic approaches. Moreover, exosomal miR-155 associated with tumors have significant functions in communicating between cells and establishing the microenvironment for cancer in GI cancers. Various types of genetic material, such as specifically miR-155 as well as proteins found in cancer-related exosomes, have the ability to be transmitted to other cells and have a function in the advancement of tumor. Therefore, it is critical to conduct a review that outlines the diverse functions of miR-155 in gastrointestinal malignancies. As a result, we present a current overview of the role of miR-155 in gastrointestinal cancers. Our research highlighted the role of miR-155 in GI cancers and covered critical issues in GI cancer such as pharmacologic inhibitors of miRNA-155, miRNA-155-assosiated circular RNAs, immune-related cells contain miRNA-155. Importantly, we discussed miRNA-155 in GI cancer resistance to chemotherapy, diagnosis and clinical trials. Furthermore, the function of miR-155 enclosed in exosomes that are released by cancer cells or tumor-associated macrophages is also covered.

WTAP-mediated m6A modification of circ_0032463 promotes osteosarcoma progression by sponging miR-145-5p and regulating GFRA1 expression

Osteosarcoma (OS) is the most frequent bone malignancy in humans. Previous evidence suggest that circ_0032463 is an oncogenic circular RNA (circRNA) in various cancers, including OS. However, the molecular mechanism of circ_0032463 involved in OS is still unclear. Circ_0032463, microRNA-145-5p (miR-145-5p), GDNF receptor alpha 1 (GFRA1), and Wilms tumor 1-associated protein (WTAP) levels were determined using real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, migration, invasion, and angiogenesis were analyzed using 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and tube formation assays. Western blot analysis was performed to measure matrix metalloproteinase 2 (MMP2), MMP9, GFRA1, and WTAP protein levels. Binding between miR-145-5p and circ_0032463 or GFRA1 was confirmed using a dual-luciferase reporter and pull-down assay. The biological role of circ_0032463 on OS cell growth was also analyzed using a xenograft tumor model in vivo. Methylated RNA immunoprecipitation assay validated the interaction between WTAP and circ_0032463. Circ_0032463, GFRA1, and WTAP levels were increased, and miR-145-5p was decreased in OS tissues and cells. Circ_0032463 deficiency might hinder OS cell proliferation, migration, invasion, angiogenesis, and promote apoptosis in vitro. Mechanically, circ_0032463 worked as a miR-145-5p sponge to increase GFRA1 expression. Repression of circ_0032463 knockdown on tumor cell growth was proved in vivo. Besides, N6-methyladenosine (m6A) modification facilitates the biogenesis of circ_0032463. Taken together, m6A-mediated biogenesis of circ_0032463 facilitates OS cell malignant biological behavior partly via regulating the miR-145-5p/GFRA1 axis, suggesting a promising molecular marker for OS treatment.

An ensemble approach for circular RNA-disease association prediction using variational autoencoder and genetic algorithm

Circular RNAs (circRNAs) are endogenous non-coding RNAs with a covalently closed loop structure. They have many biological functions, mainly regulatory ones. They have been proven to modulate protein-coding genes in the human genome. CircRNAs are linked to various diseases like Alzheimer's disease, diabetes, atherosclerosis, Parkinson's disease and cancer. Identifying the associations between circular RNAs and diseases is essential for disease diagnosis, prevention, and treatment. The proposed model, based on the variational autoencoder and genetic algorithm circular RNA disease association (VAGA-CDA), predicts novel circRNA-disease associations. First, the experimentally verified circRNA-disease associations are augmented with the synthetic minority oversampling technique (SMOTE) and regenerated using a variational autoencoder, and feature selection is applied to these vectors by a genetic algorithm (GA). The variational autoencoder effectively extracts features from the augmented samples. The optimized feature selection of the genetic algorithm effectively carried out dimensionality reduction. The sophisticated feature vectors extracted are then given to a Random Forest classifier to predict new circRNA-disease associations. The proposed model yields an AUC value of 0.9644 and 0.9628 under 5-fold and 10-fold cross-validations, respectively. The results of the case studies indicate the robustness of the proposed model.

Hsa_circ_0064636 regulates voltage dependent anion channel 1/ubiquitination factor E4A through miR‑326/miR‑503‑5 in osteosarcoma

Circular RNAs (circRNAs) are a subclass of non-coding RNAs that are important for the regulation of gene expression in eukaryotic organisms. CircRNAs exert various regulatory roles in cancer progression. However, the role of hsa_circ_0064636 in osteosarcoma (OS) remains poorly understood. In the present study, the expression of hsa_circ_0064636 in OS cell lines was measured by reverse transcription-quantitative PCR (RT-qPCR). Differentially expressed mRNAs and microRNAs (miRNA or miRs) were screened using mRNA(GSE16088) and miRNA(GSE65071) expression datasets for OS. miRNAs that can potentially interact with hsa_circ_0064636 were predicted using RNAhybrid, TargetScan and miRanda. Subsequently, RNAhybrid, TargetScan, miRanda, miRWalk, miRMap and miRNAMap were used for target gene prediction based on the overlapping miRNAs to construct a circ/miRNA/mRNA interaction network. Target genes were subjected to survival analysis using PROGgeneV2, resulting in a circRNA/miRNA/mRNA interaction sub-network with prognostic significance. miRNA and circRNA in the subnetwork may also have survival significance, but relevant data are lacking and needs to be further proved. RT-qPCR demonstrated that hsa_circ_0064636 expression was significantly increased in OS cell lines. miR-326 and miR-503-5p were identified to be target miRNAs of hsa_circ_0064636. Among the target genes obtained from the miR-326 and miR-503-5p screens, ubiquitination factor E4A (UBE4A) and voltage dependent anion channel 1 (VDAC1) were respectively identified to significantly affect prognosis; only miR-326 targets UBE4A and only miR-503 targets VDAC1. To conclude, these aforementioned findings suggest that hsa_circ_0064636 may be involved in the development of OS by sponging miR-503-5p and miR-326to inhibit their effects, thereby regulating the expression of VDAC1 and UBE4A.

Investigation of the Circular Transcriptome in Alzheimer's Disease Brain

Circular RNAs (circRNAs) are a subclass of non-coding RNAs which have demonstrated potential as biomarkers for Alzheimer's disease (AD). In this study, we conducted a comprehensive exploration of the circRNA transcriptome within AD brain tissues. Specifically, we assessed circRNA expression patterns in the dorsolateral prefrontal cortex collected from nine AD-afflicted individuals and eight healthy controls. Utilising two circRNA detection tools, CIRI2 and CIRCexplorer2, we detected thousands of circRNAs and performed a differential expression analysis. CircRNAs which exhibited statistically significantly differential expression were identified as AD-specific differentially expressed circRNAs. Notably, our investigation revealed 120 circRNAs with significant upregulation and 1325 circRNAs displaying significant downregulation in AD brains when compared to healthy brain tissue. Additionally, we explored the expression profiles of the linear RNA counterparts corresponding to differentially expressed circRNAs in AD-afflicted brains and discovered that the linear RNA counterparts exhibited no significant changes in the levels of expression. We used CRAFT tool to predict that circUBE4B had potential to target miRNA named as hsa-miR-325-5p, ultimately regulated CD44 gene. This study provides a comprehensive overview of differentially expressed circRNAs in the context of AD brains, underscoring their potential as molecular biomarkers for AD. These findings significantly enhance our comprehension of AD's underlying pathophysiological mechanisms, offering promising avenues for future diagnostic and therapeutic developments.

Construction of competing endogenous RNA networks in systemic lupus erythematosus by integrated analysis

Objective

Systemic lupus erythematosus (SLE) is a disease characterised by immune inflammation and damage to multiple organs. Recent investigations have linked competing endogenous RNAs (ceRNAs) to lupus. However, the exact mechanism through which the ceRNAs network affects SLE is still unclear. This study aims to investigate the regulatory functions of the ceRNAs network, which are important pathways that control the pathophysiological processes of SLE.

Methods

CircRNA microarray for our tested assays were derived from bone marrow samples from three healthy individuals and three SLE patients in our hospital. The other sequencing data of circRNA, miRNA and mRNA were obtained from Gene Expression Omnibus (GEO) datasets. Using the limma package of R program, the differential expression of mRNA and miRNA in the GEO database was discovered. Then predicted miRNA-mRNA and circRNA-miRNA were established using miRMap, miRanda, miRDB, TargetScan, and miTarBase. CircRNA-miRNA-mRNA ceRNA network was constructed using Cytoscape, and hub genes were screened using a protein-protein interaction network. Immune infiltration analysis of the hub gene was also performed by CIBERSORT and GSEA.

Results

230 overlapped circRNAs, 86 DEmiRNAs and 2083 DEmRNAs were identified in SLE patients as compared to healthy controls. We constructed a circRNA-miRNA-mRNA ceRNAs network contained 11 overlapped circRNAs, 9 miRNAs and 51 mRNAs. ESR1 and SIRT1 were the most frequently associated protein-protein interactions in the PPI network. KEGG analysis showed that DEGs was enriched in FoxO signaling pathway as well as lipids and atherosclerosis. We constructed a novel circRNA-miRNA-mRNA ceRNA network (HSA circ 0000345- HSA miR-22-3-P-ESR1/SIRT1) that may have a major impact on SLE.

Conclusion

Through this bioinformatics and integrated analysis, we suggest a regulatory role for ceRNA network in the pathogenesis and treatment of SLE.

EIF4A3-negatively driven circular RNA β-catenin (circβ-catenin) promotes colorectal cancer progression via miR-197-3p/CTNND1 regulatory axis

BACKGROUND

Circβ-catenin, our first reported circRNA, has been reported to mediate tumorigenesis in various cancers. However, its biological functions and underlying mechanisms in colorectal cancer (CRC) remain unknown.

METHODS

The qRT-PCR examination was used to detect the expression of circβ-catenin, miR-197-3p, and CTNND1 in cells and human tissues. Western blot was conducted to detect the protein expression levels. The biological function of circβ-catenin was verified by MTT, colony formation, wound healing, and transwell assays. The in vivo effects of circβ-catenin were verified by nude mice xenograft and metastasis models. The regulatory network of circβ-catenin/miR-197-3p/CTNND1 was confirmed via dual-luciferase reporter and RIP assays.

RESULTS

In the present study, circβ-catenin was found to promote CRC cell proliferation and metastasis in vitro and in vivo. Mechanistically, circβ-catenin served as miRNA decoy to directly bind to miR-197-3p, then antagonized the repression of the target gene CTNND1, and eventually promoted the malignant phenotype of CRC. More interestingly, the inverted repeated Alu pairs termed AluJb1/2 and AluY facilitated the biogenesis of circβ-catenin, which could be partially reversed by EIF4A3 binding to Alu element AluJb2.

CONCLUSIONS

Our findings illustrated a novel mechanism of circβ-catenin in modulating CRC tumorigenesis and metastasis, which provides a potential therapeutic target for CRC patients.

CircFBXW4 Suppresses Colorectal Cancer Progression by Regulating the MiR-338-5p/SLC5A7 Axis

Dysregulated circular RNAs (circRNAs) contribute to tumourigenesis and cancer progression. However, the expression patterns and biological functions of circRNAs in colorectal cancer (CRC) remain elusive. Here, RNA sequencing and bioinformatics analyses are applied to screen for aberrantly expressed circRNAs. The expression of circFBXW4 in CRC tissues and cell lines is determined by quantitative real-time PCR. A series of in vitro and in vivo biological function assays are implemented to assess the functions of circFBXW4. The regulatory mechanisms linking circFBXW4, miR-338-5p, and SLC5A7 are explored by western blotting, dual luciferase reporter assays, and RNA pull-down assays. CircFBXW4 is dramatically downregulated in CRC tissues and cell lines. circFBXW4 downregulation is clearly correlated with malignant features and patient overall survival in CRC. Functionally, ectopic expression of circFBXW4 strikingly impairs the proliferation, migration, and invasion capacities of CRC cells in vitro and in vivo, whereas circFBXW4 knockdown has the opposite effects. Mechanistically, circFBXW4 competitively binds to miR-338-5p and prevents it from interacting with and repressing its target SLC5A7, thus suppressing the progression of CRC. This study reveals the specific critical role of circFBXW4 in inhibiting CRC progression via the miR-338-5p/SLC5A7 axis and provides an additional target for eradicating CRC.

The mechanisms behind the dual role of long non-coding RNA (lncRNA) metastasis suppressor-1 in human tumors: Shedding light on the molecular mechanisms

When the expression levels of metastasis suppressor-1 (MTSS1) were discovered to be downregulated in a metastatic cancer cell line in 2002, it was proposed that MTSS1 functioned as a suppressor of metastasis. The 755 amino acid long protein MTSS1 connects to actin and organizes the cytoskeleton. Its gene is located on human chromosome 8q24. The suppressor of metastasis in metastatic cancer was first found to be MTSS1. Subsequent reports revealed that MTSS1 is linked to the prevention of metastasis in a variety of cancer types, including hematopoietic cancers like diffuse large B cell lymphoma and esophageal, pancreatic, and stomach cancers. Remarkably, conflicting results have also been documented. For instance, it has been reported that MTSS1 expression levels are elevated in a subset of melanomas, hepatocellular carcinoma associated with hepatitis B, head and neck squamous cell carcinoma, and lung squamous cell carcinoma. This article provides an overview of the pathological effects of lncRNA MTSS1 dysregulation in cancer. In order to facilitate the development of MTSS1-based therapeutic targeting, we also shed light on the current understanding of MTS1.

CircALMS1 Alleviates Pulmonary Microvascular Endothelial Cell Dysfunction in Pulmonary Hypertension

BACKGROUND

Circular RNAs can serve as regulators influencing the development of pulmonary hypertension (PH). However, their function in pulmonary vascular intimal injury remains undefined. Thus, we aimed to identify specifically expressed circular RNAs in pulmonary microvascular endothelial cells (PMECs) under hypoxia and PH.

METHODS AND RESULTS

Deep RNA sequencing and quantitative real-time polymerase chain reaction revealed that circALMS1 (circular RNA Alstrom syndrome protein 1) was reduced in human PMECs under hypoxia (P<0.0001). Molecular biology and histopathology experiments were used to elucidate the roles of circALMS1 in regulating PMEC dysfunction among patients with PH. The circALMS1 expression was decreased in the plasma of patients with PH (P=0.0315). Patients with lower circALMS1 levels had higher risk of death (P=0.0006). Moreover, the circALMS1 overexpression of adeno-associated viruses improved right ventricular function and reduced pulmonary vascular remodeling in monocrotaline-PH and sugen/hypoxia-PH rats (P<0.05). Furthermore, circALMS1 overexpression promoted apoptosis and inhibited PMEC proliferation and migration under hypoxia by directly downregulating miR-17-3p (P<0.05). Dual luciferase assay confirmed the direct binding of circALMS1 to miR-17-3p and miR-17-3p binding to its target gene YT521-B homology domain-containing family protein 2 (YTHDF2) (P<0.05). The YTHDF2 levels were also downregulated in hypoxic PMECs (P<0.01). The small interfering RNA YTHDF2 reversed the effects of miR-17-3p inhibitors on PMEC proliferation, migration, and apoptosis. Finally, the results indicated that, although YTHDF2, as an N(6)-methyladenosine reader protein, contributes to the degradation of many circular RNAs, it could not regulate the circALMS1 levels in PMECs (P=0.9721).

CONCLUSIONS

Our study sheds new light on circALMS1-regulated dysfunction of PMECs by the miR-17-3p/YTHDF2 pathway under hypoxia and provides insights into the underlying pathogenesis of PH.

Suppression of circular RNA serum and glucocorticoid-induced kinase 1 elevates antioxidant molecules and angiogenesis in trophoblast cells to attenuate preeclampsia via microRNA-508-3p to target and restrain PUM homolog 1

AIM

Preeclampsia (PE) is a pregnancy-specific syndrome characterized by hypertension and proteinuria. Recently, multiple circular RNAs (circRNAs) were considered latent clinical diagnostic markers or therapeutic targets. This study was to explore the impact of circRNA serum and glucocorticoid-induced kinase 1 (SGK1) on PE via influencing the microRNA (miR)-508-3p/PUM homolog 1 (PUM1) axis.

METHODS

Placental tissues of 34 pregnant women with PE and 34 normal pregnant women were collected to measure circRNA SGK1 (circSGK1), miR-508-3p, and PUM1. Human placental trophoblasts HTR-8/SVneo were transfected with plasmids, thereafter to observe proliferation, migration, invasion, and apoptosis, analyze antioxidant molecules Troxerutin (TXN), Glutamate-cysteine ligase catalytic subunit (GCLC), NAD (P) H-quinone oxidoreductase 1 (NQO1), and determine angiogenesis. After the construction of the PE rat model, antioxidant molecules TXN, GCLC, and NQO1, vascular-associated factor vascular endothelial growth factor A (VEGF-A), and histopathological conditions were tested. Examination of the binding of circSGK1 and miR-508-3p with PUM1 was performed.

RESULTS

Our data showed that circSGK1 expression was elevated in the placenta of patients with PE. Silenced circSGK1 or elevated miR-508-3p promoted the growth and antioxidant molecules and angiogenesis in trophoblast cells; CircSGK1 combined with miR-508-3p, and miR-508-3p targeted PUM1.

CONCLUSIONS

In summary, suppression of circSGK1 augments antioxidant molecules and angiogenesis in trophoblast cells to attenuate PE via miR-508-3p to target PUM1.

Plant non-coding RNAs: The new frontier for the regulation of plant development and adaptation to stress

Most plant transcriptomes constitute functional non-coding RNAs (ncRNAs) that lack the ability to encode proteins. In recent years, more research has demonstrated that ncRNAs play important regulatory roles in almost all plant biological processes by modulating gene expression. Thus, it is important to study the biogenesis and function of ncRNAs, particularly in plant growth and development and stress tolerance. In this review, we systematically explore the process of formation and regulatory mechanisms of ncRNAs, particularly those of microRNAs (miRNAs), small interfering RNAs (siRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Additionally, we provide a comprehensive overview of the recent advancements in ncRNAs research, including their regulation of plant growth and development (seed germination, root growth, leaf morphogenesis, floral development, and fruit and seed development) and responses to abiotic and biotic stress (drought, heat, cold, salinity, pathogens and insects). We also discuss research challenges and provide recommendations to advance the understanding of the roles of ncRNAs in agronomic applications.

Circular RNA circWNK1 inhibits the progression of gastric cancer via regulating the miR-21-3p/SMAD7 axis

Gastric cancer (GC) is a highly aggressive malignancy with limited treatment options for advanced-stage patients. Recent studies have highlighted the role of circular RNA (circRNA) as a novel regulator of cancer progression in various malignancies. However, the underlying mechanisms by which circRNA contributes to the development and progression of GC remain poorly understood. In this study, we utilized microarrays and real-time quantitative polymerase chain reaction (qRT-PCR) to identify and validate a downregulated circRNA, hsa_circ_0003251 (referred to as circWNK1), in paired GC and normal tissues. Through a series of in vitro and in vivo gain-of-function and loss-of-function assays, we demonstrated that circWNK1 exerts inhibitory effects on the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of GC cells. Additionally, we discovered that circWNK1 acts as a competitive endogenous RNA (ceRNA) for SMAD7 by sequestering miR-21-3p. Our findings were supported by comprehensive biological information analysis, as well as RNA pull-down, luciferase reporter gene, and western blot assays. Notably, the downregulation of circWNK1 in GC cells resulted in reduced SMAD7 expression, subsequently activating the TGF-β signaling pathway. Collectively, our study reveals that circWNK1 functions as a tumor suppressor in GC by regulating the miR-21-3p/SMAD7-mediated TGF-β signaling pathway. Furthermore, circWNK1 holds promise as a potential biomarker for the diagnosis and treatment of GC.

Biological role and regulation of circular RNA as an emerging biomarker and potential therapeutic target for cancer

Circular RNAs (circRNAs) are a unique family of endogenous RNAs devoid of 3' poly-A tails and 5' end caps. These single-stranded circRNAs, found in the cytoplasm, are synthesized via back-splicing mechanisms, merging introns, exons, or both, resulting in covalently closed circular loops. They are profusely expressed across the eukaryotic transcriptome and offer heightened stability against exonuclease RNase R compared to linear RNA counterparts. This review endeavors to provide a comprehensive overview of circRNAs' characteristics, biogenesis, and mechanisms of action. Furthermore, aimed to shed light on the potential of circRNAs as significant biomarkers in various cancer types. It has been performed an exhaustive literature review, drawing on recent studies and findings related to circRNA characteristics, synthesis, function, evaluation techniques, and their associations with oncogenesis. CircRNAs are intricately associated with tumor progression and development. Their multifaceted roles encompass gene regulation through the sponging of proteins and microRNAs, controlling transcription and splicing, interacting with RNA binding proteins (RBPs), and facilitating gene translation. Due to these varied roles, circRNAs have become a focal point in tumor pathology investigations, given their promising potential as both biomarkers and therapeutic agents. CircRNAs, due to their unique biogenesis and multifunctionality, hold immense promise in the realm of oncology. Their stability, widespread expression, and intricate involvement in gene regulation underscore their prospective utility as reliable biomarkers and therapeutic targets in cancer. As our understanding of circRNAs deepens, advanced techniques for their detection, evaluation, and manipulation will likely emerge. These advancements might catalyze the translation of circRNA-based diagnostics and therapeutics into clinical practice, potentially revolutionizing cancer care and prognosis.

Biological landscape and nanostructural view in development and reversal of oxaliplatin resistance in colorectal cancer

The treatment of cancer patients has been mainly followed using chemotherapy and it is a gold standard in improving prognosis and survival rate of patients. Oxaliplatin (OXA) is a third-platinum anti-cancer agent that reduces DNA synthesis in cancer cells to interfere with their growth and cell cycle progression. In spite of promising results of using OXA in cancer chemotherapy, the process of drug resistance has made some challenges. OXA is commonly applied in treatment of colorectal cancer (CRC) as a malignancy of gastrointestinal tract and when CRC cells increase their proliferation and metastasis, they can obtain resistance to OXA chemotherapy. A number of molecular factors such as CHK2, SIRT1, c-Myc, LATS2 and FOXC1 have been considered as regulators of OXA response in CRC cells. The non-coding RNAs are able to function as master regulator of other molecular pathways in modulating OXA resistance. There is a close association between molecular mechanisms such as apoptosis, autophagy, glycolysis and EMT with OXA resistance, so that apoptosis inhibition, pro-survival autophagy induction and stimulation of EMT and glycolysis can induce OXA resistance in CRC cells. A number of anti-tumor compounds including astragaloside IV, resveratrol and nobiletin are able to enhance OXA sensitivity in CRC cells. Nanoparticles for increasing potential of OXA in CRC suppression and reversing OXA resistance have been employed in cancer chemotherapy. These subjects are covered in this review article to shed light on molecular factors resulting in OXA resistance.

Emerging role of microRNAs as regulators of protein kinase C substrate MARCKS and MARCKSL1 in cancer

MicroRNAs (miRNAs) have emerged as pivotal regulators of gene expression, playing essential roles in diverse cellular processes, including the development and progression of cancer. Among the numerous proteins influenced by miRNAs, the MARCKS/MARCKSL1 protein, a key regulator of cellular cytoskeletal dynamics and membrane-cytosol communication, has garnered significant attention due to its multifaceted involvement in various cancer-related processes, including cell migration, invasion, metastasis, and drug resistance. Motivated by the encouraging early clinical success of peptides targeting MARCKS in several pathological conditions, this review article delves into the intricate interplay between miRNAs and the MARCKS protein in cancer. Herein, we have highlighted the latest findings on specific miRNAs that modulate MARCKS/MARCKSL1 expression, providing a comprehensive overview of their roles in different cancer types. We have underscored the need for in-depth investigations into the therapeutic feasibility of targeting the miRNA-MARCKS axis in cancer, taking cues from the successes witnessed in related fields. Unlocking the full potential of miRNA-mediated MARCKS regulation could pave the way for innovative and effective therapeutic interventions against various cancer types.

A novel upregulated hsa_circ_0032746 regulates the oncogenesis of esophageal squamous cell carcinoma by regulating miR-4270/MCM3 axis

INTRODUCTION

Circular RNAs (CircRNA) have emerged as an interest of research in recent years due to its regulatory role in various kinds of cancers of human body. Esophageal squamous cell carcinoma (ESCC) is one of the major disease subtype in Asian countries, including China. CircRNAs are formed by back-splicing covalently joined 3'- and 5'- ends rather than canonical splicing and are found to have binding affinity with miRNAs that conjointly contribute to oncogenesis.

MATERIALS AND METHODS

4 pairs of normal, cancer adjacent tissues and cancer tissues were analyzed by high-throughput RNA sequencing and 84 differentially upregulated circRNAs were detected in cancer tissues. hsa_circ_0032746 was silenced by siRNA and lentivirus and then further proliferation, migration and invasion were performed by CCK-8 and transwell assays. Bioinformatic analysis  predicted binding affinity of circRNA/miRNA/mRNA axis.

RESULTS

After qPCR validation, we selected a novel upregulated hsa_circ_0032746 to explore its biogenetic functions which showed high expression in cancer tissues but not in cancer adjacent tissues. The clinicopathological relation of hsa_circ_0032746 showed positive correlation with the tumor location (P = 0.026) and gender (P = 0.05). We also predicted that hsa_circ_0032746 could sponge with microRNA. Bioinformatic analysis predicted 11 microRNA response element (MRE) sequences of hsa_circ_0032746 and dual luciferase reporter assay confirmed binding affinity with miR4270 evidencing further study of circRNA/miRNA role. The knockdown of hsa_circ_0032746 by siRNA and lentivirus demonstrated that proliferation, invasion and migration of ESCC were inhibited in vitro and vivo experiments. Bioinformatic analysis further predicted MCM3 as a target of miR-4270 and was found upregulated in ESCC upon validation. miR4270 mimic decreased the level of hsa_circ_0032746 and MCM3 while further rescue experiments demonstrated that hsa_circ_0032746 was dependent on miR4270/MCM3 axis on the development process of ESCC.

CONCLUSION

We revealed for the first time that circ_0032746/mir4270/MCM3 contributes in proliferation, migration and invasion of ESCC and could have potential prognostic and therapeutic significance.

Significant CircRNAs in liver cancer stem cell exosomes: mediator of malignant propagation in liver cancer?

Hepatocellular carcinoma (HCC), one of the most prevalent forms of cancer worldwide, presents a significant global healthcare challenge. Cancer stem cells (CSCs), which can influence neighboring non-CSCs, are believed to play a crucial role in tumor growth and resistance to treatment, but the specific mechanisms and mediators are not fully understood. Regulation of the CSC state is considered an ideal therapeutic strategy both in the early stages of tumor formation and within established tumors. Exosomes have emerged as key players in intercellular communication, similar to classical hormone signaling, and are essential for facilitating communication between cells in liver cancer. Here, by coupling immunomagnetic bead sorting and exosomal sequencing, we found that exosome-derived circRNAs enriched in liver cancer CSCs were the key subsets with stemness characteristics and ultimately promoted HCC development. Of interest, we found that circ-ZEB1 and circ-AFAP1 are strongly correlated with liver cancer stemness and a poor prognosis, and can regulate the epithelial-mesenchymal transition (EMT) process. Our novel exosome-derived circRNAs play a vital role as key components of various intercellular crosstalk and communication systems in malignant transmission. This finding not only provides valuable support for utilizing plasma exosomal circRNAs as clinical prognostic indicators for HCC patients but also highlights a new research direction in exploring the signaling between liver CSCs and the messenger molecules contained within exosomes.

ND630 controls ACACA and lipid reprogramming in prostate cancer by regulating the expression of circKIF18B_003

BACKGROUND

ND630 is believed to be a new therapy pharmacologic molecule in targeting the expression of ACACA and regulating the lipid metabolism. However, the function of ND630 in prostate cancer remains unknown. KIF18B, as an oncogene, plays a vital role in prostate cancer progression. circKIF18B_003 was derived from oncogene KIF18B and was markedly overexpressed in prostate cancer tissues. We speculated that oncoprotein KIF18B-derived circRNA circKIF18B_003 might have roles in prostate cancer promotion. The aim of this study was to validate whether ND630 could control ACACA and lipid reprogramming in prostate cancer by regulating the expression of circKIF18B_003.

METHODS

RT-qPCR was used to analyze the expression of circKIF18B_003 in prostate cancer cell lines and prostate cancer samples. circKIF18B_003 expression was modulated in prostate cancer cells using circKIF18B_003 interference or overexpression plasmid. We examined the function and effects of circKIF18B_003 in prostate cancer cells using CCK-8, colony formation, wound healing, and Transwell invasion assays and xenograft models. Fluorescence in situ hybridization (FISH) was performed to evaluate the localization of circKIF18B_003. RNA immunoprecipitation (RIP), RNA pull down, and luciferase reporter assay were performed to explore the potential mechanism of circKIF18B_003.

RESULTS

The function of ND630 was determined in this study. circKIF18B_003 was overexpressed in prostate cancer tissues, and overexpression of circKIF18B_003 was associated with poor survival outcome of prostate cancer patients. The proliferation, migration, and invasion of prostate cancer cells were enhanced after up-regulation of circKIF18B_003. circKIF18B_003 is mainly located in the cytoplasm of prostate cancer cells, and the RIP and RNA pull down assays confirmed that circKIF18B_003 could act as a sponge for miR-370-3p. Further study demonstrated that up-regulation of circKIF18B_003 increased the expression of ACACA by sponging miR-370-3p. The malignant ability of prostate cancer cells enhanced by overexpression of circKIF18B_003 was reversed by the down-regulation of ACACA. We found that overexpression of circKIF18B_003 was associated with lipid metabolism, and a combination of ND-630 and docetaxel markedly attenuated tumor growth.

CONCLUSION

ND630 could control ACACA and lipid reprogramming in prostate cancer by regulating the expression of circKIF18B_003. ND630 and circKIF18B_003 may represent a novel target for prostate cancer.

Circ_0004535/miR-1827/CASP8 network involved in type 2 diabetes mellitus with nonalcoholic fatty liver disease

Diagnostic delay in type 2 diabetes mellitus (T2DM) with nonalcoholic fatty liver disease (NAFLD) patients often leads to a serious public health problem. Understanding the pathophysiological mechanisms of disease will help develop more effective treatments. High-throughput sequencing was used to determine the expression levels of circRNAs, and mRNAs in health controls, T2DM patients, and T2DM with NAFLD patients. Differentially expressed genes (DEcircRs, DEmRs) in T2DM with NAFLD were identified by differential analysis. The miRNAs with targeted relationship with the DEcircRs and DEmRs were respectively predicted to construct a ceRNA regulatory network. In addition, enrichment analysis of DEmRs in the ceRNA network was performed. The expression of important DEcircRs was further validated by quantitative real-time PCR (qRT-PCR). The steatosis was detected in glucose treated LO2 cells by overexpressing circ_0004535, and CASP8. There were 586 DEmRs, and 10 DEcircRs in both T2DM and T2DM with NAFLD patients. Combined with predicted results and differential analysis, the ceRNA networks were constructed. The DEmRs in the ceRNA networks were mainly enriched in Toll-like receptor signaling pathway, and apoptosis. Importantly, dual luciferase experiments validated the targeted binding of hsa_circ_0004535 and hsa-miR-1827 or hsa-miR-1827 and CASP8. qRT-PCR experiments validated that hsa_circ_0004535, and CASP8 was downregulated and hsa-miR-1827 was upregulated expression in peripheral blood of T2DM with NAFLD patients. Abnormal cell morphology, and increased lipid droplet fusion were observed in the glucose treated LO2 cells, overexpression of circ_0004535 and CASP8 ameliorated these changes. Our work provides a deeper understanding of ceRNA mediated pathogenesis of T2DM with NAFLD and provides a novel strategy for treatment.

IL23R as an indicator of immune infiltration and poor prognosis in intrahepatic cholangiocarcinoma: a bioinformatics analysis

Background

Although the incidence of intrahepatic cholangiocarcinoma (CHOL) is low, the prognosis is very poor. The expression level of interleukin 23 receptor (IL23R) is linked to the occurrence and development of cancers. This study aimed to identify the role of IL23R in CHOL using bioinformatics tools and experimental validation.

Methods

Circular RNA (circRNA), microRNA (miRNA), and messenger RNA (mRNA) datasets were obtained from the Gene Expression Omnibus (GEO) database, and R software was used for data analysis and visualization. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to conduct functional enrichment analysis, which was verified with gene set enrichment analysis software. Clinical data were obtained from The Cancer Genome Atlas (TCGA), and survival analyses were performed using the DriverDBv3 database and the Gene Expression Profiling Interactive Analysis website. The TIMER2.0 database provided us for immune cell infiltration analysis results of IL23R. Real-time quantitative polymerase chain reaction (RT-qPCR) was used for IL23R expression verification.

Results

Differentially expressed (DE) mRNAs were enriched in phosphoinositide 3-kinase-serine/threonine kinase signaling pathway, immune-related tumor microenvironment (TME), and amino acid metabolism, etc. In addition, expression of IL23R was associated with immune infiltration-related cells. Furthermore, a circRNA-miRNA-IL23R network and a IL23R protein-protein interaction network were established. Most importantly, IL23R, as a prognostic gene, was found to have a low expression in CHOL.

Conclusions

A circRNA-miRNA-IL23R network was identified, and it was found that IL23R may be a prognostic and immune-related biomarker in CHOL, which is worthy of further exploration.

Hypoxic papillary thyroid carcinoma cells-secreted exosomes deliver miR-221-3p to normoxic tumor cells to elicit a pro-tumoral effect by regulating the ZFAND5

Papillary thyroid cancer (PTC) has seen a worldwide expansion in incidence in the past three decades. Tumor-derived exosomes have been associated with the metastasis of cancer cells and are present within the local hypoxic tumor microenvironment, where they mediate intercellular communication by transferring molecules including microRNAs (miRNAs) between cells. Although miRNAs have been shown to serve as non-invasive biomarkers for cancer diagnosis, the role of hypoxia-induced tumor-derived exosomes in PTC progression remains unclear. Herein, we investigated the differentially expressed miRNA expression profiles from GEO datasets (GSE191117 and GSE151180) by using the DESeq package in R and identified a novel role for miR-221-3p as an oncogene in PTC development. In vivo and in vitro loss and gain assays were used to clarify the mechanism of hypoxic PTC cells derived exosomal-miR-221-3p in PTC. miR-221-3p was upregulated in human PTC plasma exosomes, tissues and cell lines. We found that hypoxic PTC cells derived exosomal-miR-221-3p promoted normoxic PTC cells proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) in vitro, while inhibition of miR-221-3p limited PTC tumor growth in our PTC xenograft model in nude mice. We finally identified ZFAND5, to be a miR-221-3p target. Mechanistically, hypoxic PTC cell lines-derived exosomes carrying miR-221-3p promoted PTC tumorigenesis by regulating ZFAND5. Our findings further the understanding of the underlying mechanisms associated with PTC progression and identify exosomal-miR-221-3p as a potential biomarker for the diagnosis and prognosis of PTC patients. Our study also suggests that miR-221-3p inhibitors could be a potential treatment strategy for PTC.

Dynamic observation of circRNA and mRNA profiles in a rat model of deep vein thrombosis

The goal of the present study was to identify different transcriptome expression profiles involved in the pathogenesis of deep vein thrombosis (DVT), and to illustrate the diagnostic and therapeutic potential of circular RNAs (circRNAs) and mRNAs in DVT progression. A Sprague-Dawley rat model of DVT was successfully established through the stenosis method and samples were sequenced at four time points (1, 6 and 12 h, and 3 days after ligation) to observe the dynamic changes in circRNAs and mRNAs during DVT progression. RNA sequencing was used to analyze the circRNA and mRNA expression profiles, and associated functions and pathways, in the blood of DVT rats at the four time points. In addition, Short Time Series Expression Miner (STEM) analysis was performed to explore temporal gene expression. Differential expression of 1,680, 4,018, 3,724, and 3,036 circRNAs, and 400, 1,176, 373, and 573 mRNAs was observed in the 1, 6 and 12 h, and 3-day groups, respectively, compared with the sham group (fold change >2.0 or <-2.0, P<0.05). Functional enrichment analysis indicated that differentially expressed mRNAs were associated with the following terms: Immune response, cell activation, blood stasis facilitated organelle, extracellular membrane-bounded organelle, and blood microparticle, oxygen transporter activity. STEM analysis indicated that the expression of 366 circRNAs in circRNA profile 45 and 270 mRNAs in mRNA profile 45 was consistent with thrombus progression. Enrichment analysis was performed on mRNA profile 45. The main Gene Ontology annotations were chromosome segregation, mitotic sister chromatid segregation, cell cycle process, and ligand-dependent nuclear receptor transcription coactivator activity. Pathway enrichment analysis identified the platelet-associated pathway, immune-associated pathway, and inflammation-relation pathway. According to the enriched platelet-associated pathways, four mRNAs and ten candidate circRNAs were selected for reverse transcription-quantitative PCR verification. The expression of nine of the ten circRNAs and all four mRNAs was consistent with the sequencing results. In summary, differentially expressed circRNAs and mRNAs are dynamically involved in DVT development. Dysregulated transcriptome profiles and the corresponding functions and pathways may provide mechanistic insights into DVT diagnosis and treatment.

MicroRNAs as the critical regulators of Forkhead box protein family during gynecological and breast tumor progression and metastasis

Gynecological and breast tumors are one of the main causes of cancer-related mortalities among women. Despite recent advances in diagnostic and therapeutic methods, tumor relapse is observed in a high percentage of these patients due to the treatment failure. Late diagnosis in advanced tumor stages is one of the main reasons for the treatment failure and recurrence in these tumors. Therefore, it is necessary to assess the molecular mechanisms involved in progression of these tumors to introduce the efficient early diagnostic markers. Fokhead Box (FOX) is a family of transcription factors with a key role in regulation of a wide variety of cellular mechanisms. Deregulation of FOX proteins has been observed in different cancers. MicroRNAs (miRNAs) as a group of non-coding RNAs have important roles in post-transcriptional regulation of the genes involved in cellular mechanisms. They are also the non-invasive diagnostic markers due to their high stability in body fluids. Considering the importance of FOX proteins in the progression of breast and gynecological tumors, we investigated the role of miRNAs in regulation of the FOX proteins in these tumors. MicroRNAs were mainly involved in progression of these tumors through FOXM, FOXP, and FOXO. The present review paves the way to suggest a non-invasive diagnostic panel marker based on the miRNAs/FOX axis in breast and gynecological cancers.

Exosomal circBBS2 inhibits ferroptosis by targeting miR-494 to activate SLC7A11 signaling in ischemic stroke

Umbilical cord-mesenchymal stem cells (UC-MSCs)-derived exosomes have been considered as an effective treatment for ischemic stroke. CircRNA BBS2 (circBBS2) was demonstrated to be down-regulated in patients with ischemic stroke. However, the role of UC-MSCs-derived exosomal circBBS2 in ischemic stroke and potential mechanisms remain unclear. Hypoxia/reperfusion (H/R)-exposed SH-SY5Y cells and middle cerebral artery occlusion (MCAO)-treated rats were served as in vitro and in vivo models of ischemic stroke. Target gene expression was detected by qRT-PCR. Cell viability was assessed by MTT assay. Ferroptosis was determined by iron, MDA, GSH, and lipid ROS levels. Protein levels were measured by Western blotting. The target relationships among circBBS2, miR-494, and SLC7A11 were validated by RNA-pull down, RIP, and dual-luciferase reporter assays. TTC and HE staining were performed to evaluate cerebral infarction volume and neuropathological changes. circBBS2 was lowly expressed and ferroptosis was triggered in MCAO rats and H/R-stimulated SH-SY5Y cells. UC-MSCs-derived exosomes enhanced cell viability and restrained ferroptosis via increasing circBBS2 expression in SH-SY5Y cells. Mechanistically, circBBS2 sponged miR-494 to enhance the SLC7A11 level. Knockdown of miR-494 or SLC7A11 reversed the effects of silencing circBBS2 or miR-494 on ferroptosis of SH-SY5Y cells, respectively. Furthermore, UC-MSCs-derived exosomes attenuated ischemic stroke in rats via delivering circBBS2 to inhibit ferroptosis. UC-MSCs-derived exosomal circBBS2 enhanced SLC7A11 expression via sponging miR-494, therefore repressing ferroptosis and relieving ischemic stroke. Our findings shed light on a novel mechanism for UC-MSCs-derived exosomes in the treatment of ischemic stroke.

hsa_circ_0000519 promotes the progression of lung adenocarcinoma through the hsa-miR-1296-5p/DARS axis

Emerging research indicates that circRNAs serve a crucial role in occurrence and development of cancers. This study aimed to uncover the biological role of hsa_circ_0000519 in the progression of LUAD (lung adenocarcinoma). hsa_circ_0000519 was identified by bioinformatic analysis, and its differential expression was validated in LUAD tissues and cell lines. CCK8, colony formation, wound healing, transwell assays, and xenograft tumor models were used to observe the biological functions of hsa_circ_0000519. FISH, RIP, dual luciferase reporter assays, and recovery experiments were implemented to explore the underlying mechanisms of hsa_circ_0000519. hsa_circ_0000519 was significantly upregulated in LUAD tissues and cell lines. The expression of hsa_circ_0000519 was positively correlated with T grade and TNM stage in patients with LUAD. Downregulation of hsa_circ_0000519 remarkably reduced cell proliferation, migration, invasion in vitro, and tumor growth in vivo. Mechanistic investigation demonstrated that hsa_circ_0000519 directly sponged hsa-miR-1296-5p to reduce its repressive impact on DARS as well as activate the PI3K/AKT/mTOR signaling pathway. The malignant phenotypes of LUAD cells induced by upregulation of hsa_circ_0000519 could be rescued by hsa-miR-1296-5p overexpression or knockdown of DARS. In conclusion, hsa_circ_0000519 promotes LUAD progression through the hsa-miR-1296-5p/DARS axis and may be expected as a novel biomarker and therapeutic for LUAD.

CPSF3 Promotes Pre-mRNA Splicing and Prevents CircRNA Cyclization in Hepatocellular Carcinoma

CircRNAs are crucial in tumorigenesis and metastasis, and are comprehensively downregulated in hepatocellular carcinoma (HCC). Previous studies demonstrated that the back-splicing of circRNAs was closely related to 3'-end splicing. As a core executor of 3'-end cleavage, we hypothesized that CPSF3 modulated circRNA circularization. Clinical data were analyzed to establish the prognostic correlations. Cytological experiments were performed to determine the role of CPSF3 in HCC. A fluorescent reporter was employed to explore the back-splicing mechanism. The circRNAs regulated by CPSF3 were screened by RNA-seq and validated by PCR, and changes in downstream pathways were explored by molecular experiments. Finally, the safety and efficacy of the CPSF3 inhibitor JTE-607 were verified both in vitro and in vivo. The results showed that CPSF3 was highly expressed in HCC cells, promoting their proliferation and migration, and that a high CPSF3 level was predictive of a poor prognosis. A mechanistic study revealed that CPSF3 enhanced RNA cleavage, thereby reducing circRNAs, and increasing linear mRNAs. Furthermore, inhibition of CPSF3 by JET-607 suppressed the proliferation of HCC cells. Our findings indicate that the increase of CPSF3 in HCC promotes the shift of pre-mRNA from circRNA to linear mRNA, leading to uncontrolled cell proliferation. JTE-607 exerted a therapeutic effect on HCC by blocking CPSF3.

Roles of Non-Coding RNA in Alzheimer's Disease Pathophysiology

Alzheimer's disease (AD) is a chronic neurodegenerative disorder that is accompanied by deficits in memory and cognitive functions. The disease is pathologically characterised by the accumulation and aggregation of an extracellular peptide referred to as amyloid-β (Aβ) in the form of amyloid plaques and the intracellular aggregation of a hyperphosphorelated protein tau in the form of neurofibrillary tangles (NFTs) that cause neuroinflammation, synaptic dysfunction, and oxidative stress. The search for pathomechanisms leading to disease onset and progression has identified many key players that include genetic, epigenetic, behavioural, and environmental factors, which lend support to the fact that this is a multi-faceted disease where failure in various systems contributes to disease onset and progression. Although the vast majority of individuals present with the sporadic (non-genetic) form of the disease, dysfunctions in numerous protein-coding and non-coding genes have been implicated in mechanisms contributing to the disease. Recent studies have provided strong evidence for the association of non-coding RNAs (ncRNAs) with AD. In this review, we highlight the current findings on changes observed in circular RNA (circRNA), microRNA (miRNA), short interfering RNA (siRNA), piwi-interacting RNA (piRNA), and long non-coding RNA (lncRNA) in AD. Variations in these ncRNAs could potentially serve as biomarkers or therapeutic targets for the diagnosis and treatment of Alzheimer's disease. We also discuss the results of studies that have targeted these ncRNAs in cellular and animal models of AD with a view for translating these findings into therapies for Alzheimer's disease.

Circular RNAs drive oncogenic chromosomal translocations within the MLL recombinome in leukemia

The first step of oncogenesis is the acquisition of a repertoire of genetic mutations to initiate and sustain the malignancy. An important example of this initiation phase in acute leukemias is the formation of a potent oncogene by chromosomal translocations between the mixed lineage leukemia (MLL) gene and one of 100 translocation partners, known as the MLL recombinome. Here, we show that circular RNAs (circRNAs)-a family of covalently closed, alternatively spliced RNA molecules-are enriched within the MLL recombinome and can bind DNA, forming circRNA:DNA hybrids (circR loops) at their cognate loci. These circR loops promote transcriptional pausing, proteasome inhibition, chromatin re-organization, and DNA breakage. Importantly, overexpressing circRNAs in mouse leukemia xenograft models results in co-localization of genomic loci, de novo generation of clinically relevant chromosomal translocations mimicking the MLL recombinome, and hastening of disease onset. Our findings provide fundamental insight into the acquisition of chromosomal translocations by endogenous RNA carcinogens in leukemia.

CircRNA: a rising star in leukemia

Non-coding RNA are a class of RNA that lack the potential to encode proteins. CircRNAs, generated by a post-splicing mechanism, are a newly discovered type of non-coding RNA with multi-functional covalent loop structures. CircRNAs may play an important role in the occurrence and progression of tumors. Research has shown that circRNAs are aberrantly expressed in various types of human cancers, including leukemia. In this review, we summarize the expression and function of circRNAs and their impact on different types of leukemia. We also illustrate the function of circRNAs on immune modulation and chemoresistance in leukemia and their impact on its diagnosis and prognosis. Herein, we provide an understanding of recent advances in research that highlight the importance of circRNAs in proliferation, apoptosis, migration, and autophagy in different types of leukemia. Furthermore, circRNAs make an indispensable difference in the modulation of the immunity and chemoresistance of leukemia. Increasing evidence suggests that circRNAs may play a vital role in the diagnostic and prognostic markers of leukemia because of their prominent properties. More detailed preclinical studies on circRNAs are needed to explore effective ways in which they can serve as biomarkers for the diagnosis and prognosis of leukemia in vivo.

Paclitaxel inhibits hepatocellular carcinoma tumorigenesis by regulating the circ_0005785/miR-640/GSK3β

Paclitaxel (PTX) is an effective chemotherapeutic agent for cancer patients. It has been reported that circular RNA (circRNA) circ_0005785is involved in the progression of hepatocellular carcinoma (HCC). The purpose of this study is to explore the role and mechanism of circ_0005785 in the PTX resistance of HCC. Cell viability, proliferation, invasion, migration, apoptosis, and angiogenesis were detected using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), colony formation, transwell, wound-healing, flow cytometry, and tube formation assay. Circ_0005785, microRNA-640 (miR-640), and Glycogen synthase kinase-3 beta (GSK3β) levels were detected using real-time quantitative polymerase chain reaction. Protein levels of Proliferating cell nuclear antigen (PCNA), Bcl-2, and GSK3β were measured using western blot assay. After being predicted using Circular RNA interactome or TargetScan, binding between miR-640 and circ_0005785 or GSK3β was verified using dual-luciferase reporter and RNA Immunoprecipitation assay. PTX treatment could repress HCC cell viability, decrease circ_0005785 and GSK3β expression, and increase the miR-640 level in HCC cell lines. Furthermore, circ_0005785 and GSK3β were increased, and miR-640 was decreased in HCC tissues and cell lines. Moreover, circ_0005785 knockdown hindered proliferation, migration, invasion, angiogenesis, and boosted apoptosis in PTX-treated HCC cells in vitro. In addition, circ_0005785 silencing improved the PTX sensitivity of HCC in vivo. Mechanistically, circ_0005785 acted as a sponge of miR-640 to regulate GSK3β expression. PTX restrained HCC tumorigenesis partly via regulating the circ_0005785/miR-640/GSK3β axis, hinting at a promising therapeutic target for the HCC treatment.

Circular RNA circDLG1 contributes to HCC progression by regulating the miR-141-3p/WTAP axis

This study aims to explore novel and reliable biomarkers for predicting hepatocellular carcinoma (HCC) prognosis. Circular RNAs (circRNAs) were determined by analysis of human circRNA arrays and quantitative reverse transcription polymerase reactions. To test for an interaction between circDLG1, we used luciferase reporter assays, RNA immunoprecipitation, and fluorescence in situ hybridization assays that were employed to test the interaction between circDLG1, miR-141-3p, and WTAP. q-RT-PCR and western blot were used to evaluate the target regulation of miR-141-3p and WTAP. shRNA-mediated knockdown of circDLG1, proliferation, migration, and invasion experiment of metastasis were used to evaluate the function of circDLG. CircDLG1 rather than lining DLG1 was upregulated in HCC tissues, from HCC patients as well as HCC cell lines compared to normal controls. circDLG1 high expression in HCC patients was correlated with shorter overall survival. Knockdown of circDLG1 and miR-141-3p mimic could inhibit the tumorigenesis of HCC cells in vivo and in vitro. Importantly, we demonstrated that circDLG1 could act as a sponge of miR-141-3p to regulate the expression of WTAP, and further suppress the tumorigenesis of HCC cells. Our study reveals that circDLG1 can serve as a novel potential circulating biomarker for the detection of HCC. circDLG1 participates in the progression of HCC cells by sponging miR-141-3p with WTAP, providing new insight into the treatment of HCC.

Physiological and pathophysiological mechanisms of the molecular and cellular biology of angiogenesis and inflammation in moyamoya angiopathy and related vascular diseases

Rationale

The etiology and pathophysiological mechanisms of moyamoya angiopathy (MMA) remain largely unknown. MMA is a progressive, occlusive cerebrovascular disorder characterized by recurrent ischemic and hemorrhagic strokes; with compensatory formation of an abnormal network of perforating blood vessels that creates a collateral circulation; and by aberrant angiogenesis at the base of the brain. Imbalance of angiogenic and vasculogenic mechanisms has been proposed as a potential cause of MMA. Moyamoya vessels suggest that aberrant angiogenic, arteriogenic, and vasculogenic processes may be involved in the pathophysiology of MMA. Circulating endothelial progenitor cells have been hypothesized to contribute to vascular remodeling in MMA. MMA is associated with increased expression of angiogenic factors and proinflammatory molecules. Systemic inflammation may be related to MMA pathogenesis.

Objective

This literature review describes the molecular mechanisms associated with cerebrovascular dysfunction, aberrant angiogenesis, and inflammation in MMA and related cerebrovascular diseases along with treatment strategies and future research perspectives.

Methods and results

References were identified through a systematic computerized search of the medical literature from January 1, 1983, through July 29, 2022, using the PubMed, EMBASE, BIOSIS Previews, CNKI, ISI web of science, and Medline databases and various combinations of the keywords "moyamoya," "angiogenesis," "anastomotic network," "molecular mechanism," "physiology," "pathophysiology," "pathogenesis," "biomarker," "genetics," "signaling pathway," "blood-brain barrier," "endothelial progenitor cells," "endothelial function," "inflammation," "intracranial hemorrhage," and "stroke." Relevant articles and supplemental basic science articles almost exclusively published in English were included. Review of the reference lists of relevant publications for additional sources resulted in 350 publications which met the study inclusion criteria. Detection of growth factors, chemokines, and cytokines in MMA patients suggests the hypothesis of aberrant angiogenesis being involved in MMA pathogenesis. It remains to be ascertained whether these findings are consequences of MMA or are etiological factors of MMA.

Conclusions

MMA is a heterogeneous disorder, comprising various genotypes and phenotypes, with a complex pathophysiology. Additional research may advance our understanding of the pathophysiology involved in aberrant angiogenesis, arterial stenosis, and the formation of moyamoya collaterals and anastomotic networks. Future research will benefit from researching molecular pathophysiologic mechanisms and the correlation of clinical and basic research results.