CircBCAR3 accelerates esophageal cancer tumorigenesis and metastasis via sponging miR-27a-3p

RNA-binding protein quaking: a multifunctional regulator in tumour progression

BACKGROUND

Quaking (QKI) is a member of the signal transduction and activators of RNA (STAR) family, performing a crucial multifunctional regulatory role in alternative splicing, mRNA precursor processing, mRNA transport and localization, mRNA stabilization, and translation during tumour progression. Abnormal QKI expression or fusion mutations lead to aberrant RNA and protein expression, thereby promoting tumour progression. However, in many types of tumour, QKI played a role as tumour suppressor, the regulatory role of QKI in tumour progression remains ambiguous.

OBJECTIVES

This review aims to analyze the isoform and function of QKI, the impact of QKI-regulated gene expression or signalling pathway alterations on tumour progression, and its potential clinical applications as a predictive marker or target for tumour therapy.

METHODS

We reviewed recent studies and summarized the function of QKI alteration in tumour progression.

RESULTS

QKI mediate post-transcriptional gene regulation including alternative splicing, polyadenylation, mRNA stabilization, mRNA subcellular location, and noncoding RNA by binding to the QRE elements of targeted nucleotide. The dysregulation of QKI is intricately correlated to tumour proliferation, metastasis, angiogenesis, tumor stem cells, the tumour microenvironment, and treatment sensitivity, and represents as a potential biological predictor in tumour diagnosis and prognosis.

CONCLUSIONS

QKI play a critical role as tumour suppressor or an oncogene in tumour progression due to the different splicing sites and transcripts with various tumour subtype or tumor micorenvironment. Ongoing research about QKI's functions and mechanisms persist is required to conduct for better understanding the role of QKI in tumour regulation.

CircBRWD1 promotes hepatitis B virus replication and hepatocellular carcinoma progression by regulating the miR-513a-5p/TNPO1 axis

Hepatocellular carcinoma (HCC), primarily caused by chronic hepatitis B virus (HBV) infection, remains a leading cause of liver cancer worldwide. Despite advances in antiviral therapies, persistent HBV replication, mediated by covalently closed circular DNA (cccDNA), contributes to poor prognoses and frequent recurrence of HCC. This study investigates for the first time the role of circular RNA circBRWD1 in HBV-related HCC, aiming to elucidate its function and regulatory mechanism in HBV replication and hepatocarcinogenesis. Results showed that circBRWD1 was significantly overexpressed in HBV-positive HCC tissues and cell lines compared to HBV-negative controls and promoted HBV replication by increasing cccDNA accumulation. Silencing circBRWD1 markedly reduced the levels of HBV DNA, HBV surface antigen (HBsAg), HBV e antigen (HBeAg), and HBV core antigen (HBcAg), indicating its critical role in HBV replication. Functionally, circBRWD1 knockdown led to reduced cell proliferation, colony formation, and migration while increasing apoptosis in HCC cells. Mechanistic studies revealed that circBRWD1 acts as a sponge for miR-513a-5p, thereby upregulating TNPO1, a key player in promoting HCC malignancy. Rescue experiments confirmed that TNPO1 overexpression reversed the effects of circBRWD1 depletion, restoring cell proliferation, migration, and HBV replication. Additionally, circBRWD1 depletion significantly reduced tumor growth with reduced expression of TNPO1 and increased miR-513a-5p levels in a mouse xenograft model. Collectively, this study identifies circBRWD1 as a key oncogenic circRNA that facilitates HBV replication and HCC progression via the miR-513a-5p/TNPO1 axis. Targeting circBRWD1 may offer a novel therapeutic strategy for HBV-related HCC, potentially addressing the challenge of HBV persistence and improving patient outcomes.

Knockdown NEK7 stimulates anti-tumor immune responses by NLRP3/PD-L1 signaling in esophageal cancer

BACKGROUND

Esophageal cancer is a prevalent malignancy with limited treatment options. The study aimed to understand the role and mechanism of NEK7 in esophageal cancer development.

METHODS

RNA sequencing compared esophageal cancer tissues with adjacent tissues, and real-time PCR validated NEK7 expression. Co-IP identified NLRP3 as NEK7's binding partner. We also study the effects of NEK7 knockdown on cell viability, apoptosis, migration, invasion, and the expression of NLRP3/PD-L1 in esophageal carcinoma cell lines. TIMER 2.0 analyzed immune infiltration. An animal model was used to investigate the impact of NEK7 knockdown on tumor size, survival rates, and immune cell infiltration. Licochalcone B blocked NEK7/NLRP3, enhancing CD8 T cell-mediated tumor killing. PD-1's role in T cell viability was also assessed.

RESULTS

NEK7 was observed to be markedly elevated in both tumor tissues of esophageal cancer and EC109 cells. Moreover, silencing NEK7 reduced cell viability, migration, and invasion, while enhancing cell apoptosis in vitro. Knockdown of NEK7 caused a notable reduction in levels of NLRP3 and PD-L1 in EC109 cells. NEK7 expression showed a positive correlation with immune cell infiltration. Knockdown of NEK7 decreased PD-L1 expression, while upregulation of NEK7 increased PD-L1 expression, then reversed by NLRP3 knockdown. In animal studies, NEK7 knockdown reduced tumor size and volume while improving survival. It also promoted CD4 and CD8 T cell infiltration while inhibiting Treg cells and PD-1 + CD4 and CD8 T cells. Licochalcone B blocked NEK7/NLRP3 binding, decreased cell viability of EC109 cells, and enhanced the activity of co-cultured CD8 T cells. Furthermore, Licochalcone B and anti-PD-1 treatment increased the killing ratio of EC109 cells.

CONCLUSION

In conclusion, NEK7 is a key regulator in the progression of esophageal cancer and the immune evasion. Targeting the NEK7/NLRP3 pathway may have therapeutic potential for the treatment of esophageal cancer.

Deciphering the role of circular RNAs in cancer progression under hypoxic conditions

Hypoxia, characterized by reduced oxygen levels, plays a pivotal role in cancer progression, profoundly influencing tumor behavior and therapeutic responses. A hallmark of solid tumors, hypoxia drives significant metabolic adaptations in cancer cells, primarily mediated by hypoxia-inducible factor-1α (HIF-1α), a key transcription factor activated in low-oxygen conditions. This hypoxic environment promotes epithelial-mesenchymal transition (EMT), enhancing cancer cell migration, metastasis, and the development of cancer stem cell-like properties, which contribute to therapy resistance. Moreover, hypoxia modulates the expression of circular RNAs (circRNAs), leading to their accumulation in the tumor microenvironment. These hypoxia-responsive circRNAs regulate gene expression and cellular processes critical for cancer progression, making them promising candidates for diagnostic and prognostic biomarkers in various cancers. This review delves into the intricate interplay between hypoxic circRNAs, microRNAs, and RNA-binding proteins, emphasizing their role as molecular sponges that modulate gene expression and signaling pathways involved in cell proliferation, apoptosis, and metastasis. It also explores the relationship between circRNAs and the tumor microenvironment, particularly how hypoxia influences their expression and functional dynamics. Additionally, the review highlights the potential of circRNAs as diagnostic and prognostic tools, as well as their therapeutic applications in innovative cancer treatments. By consolidating current knowledge, this review underscores the critical role of circRNAs in cancer biology and paves the way for future research aimed at harnessing their unique properties for clinical advancements. Specifically, this review examines the biogenesis, expression patterns, and mechanistic actions of hypoxic circRNAs, focusing on their ability to act as molecular sponges for microRNAs and their interactions with RNA-binding proteins. These interactions impact key signaling pathways related to tumor growth, metastasis, and drug resistance, offering new insights into the complex regulatory networks governed by circRNAs under hypoxic stress.

The emerging functions and clinical implications of circRNAs in acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a prevalent haematologic malignancy characterized by significant heterogeneity. Despite the application of aggressive therapeutic approaches, AML remains associated with poor prognosis. Circular RNAs (circRNAs) constitute a unique class of single-stranded RNAs featuring covalently closed loop structures that are ubiquitous across species. These molecules perform crucial regulatory functions in the pathogenesis of various diseases through diverse mechanisms, including acting as miRNA sponges, interacting with DNA or proteins, and encoding functional proteins/polypeptides. Recently, numerous circRNAs have been confirmed to have aberrant expression patterns in AML patients. In particular, certain circRNAs are closely associated with specific clinicopathological characteristics and thus have great potential as diagnostic/prognostic biomarkers and therapeutic targets in AML. Herein, we systematically summarize the biogenesis, degradation, and functional mechanisms of circRNAs while highlighting their clinical relevance. We also outline a series of online databases and analytical tools available to facilitate circRNA research. Finally, we discuss the current challenges and future research priorities in this evolving field.

Identification of circRNA-Based Biomarkers and ceRNA Mechanism in Non-Small Cell Lung Cancer

We aimed to identify circRNA as a biomarker in non-small cell lung cancer (NSCLC) and explore the underlying mechanism. circRNA and mRNA data were retrieved from GEO database. A series of bioinformatics analyses including differentially expressed analysis, weighted gene co-expression network analysis (WGCNA), Random Forest, and support vector machine algorithm were applied to identify the key circRNAs in NSCLC. ROC curves were used to evaluate and distinguish the roles of key circRNAs in cancer. The expression levels of circRNAs were validated via qPCR analysis. Finally, a ceRNA network was constructed. Herein, si-hsa_circ_0084443 was transfected into NSCLC cells to investigate its function in NSCLC. Five circRNAs (hsa_circ_0049271, hsa_circ_0029426, hsa_circ_0084443, hsa_circ_0015278, and hsa_circ_0024731) were identified as biomarkers in NSCLC. They exhibited potent diagnostic ability in identifying NSCLC, with AUC > 0.85. qPCR results suggested that hsa_circ_0049271, hsa_circ_0029426, and hsa_circ_0015278 were significantly downregulated and hsa_circ_0084443 and hsa_circ_0024731 were significantly upregulated in tumor tissue compared with the levels in normal tissues (P < 0.05). A ceRNA network was finally constructed. Knockdown of hsa_circ_0084443 inhibited cell growth, migration, invasion, and colony formation, and promoted apoptosis in NSCLC cell line. Five circRNAs were identified as biomarkers and demonstrated abnormal expression in NSCLC. Furthermore, ceRNA network was constructed, which can aid the mechanism exploration in the future.

Circ_0098181 binds PKM2 to attenuate liver fibrosis

Background

Liver cirrhosis seriously harms human health and fibrosis is the essential pathological process of cirrhosis. Recently, circular RNAs (circRNAs) were found to play critical roles in liver fibrosis, but the key circRNAs and precise mechanisms remained unclear. This study aimed to investigate the effect of circ_0098181 in fibrogenesis and explore its mechanism.

Methods

RNA sequencing was conducted to identify circRNA signatures in human liver cirrhotic tissues. Hepatic stellate cells (HSCs) (including primary rat HSCs, LX2, HSC-T6) and carbon tetrachloride (CCl4) induced liver cirrhosis model were used to explore the role of circ_0098181 on HSC activation and liver fibrogenesis in vitro and in vivo. RNA sequencing, RNA pull-down, mass spectrometry, and RNA immunoprecipitation (RIP) experiments were performed to elucidate the mechanism.

Results

Circ_0098181 was obviously reduced in human fibrotic liver tissues and activated HSCs. Exogenous administration of circ_0098181 blocked the activation, proliferation, and migration of HSCs in vitro and mitigated the progression of CCl4-induced liver fibrosis in vivo. Mechanistically, adenosine deaminase acting on RNA1 (ADAR1) combined with the intronic complementary sequences (ICSs) in the flanking regions, thereby regulating the biogenesis of circ_0098181. RNA sequencing and qRT-PCR revealed the suppression of circ_0098181 on pro-inflammation cytokines expression (TNFα, Fas, Cxcl11, etc.). RNA pull-down, mass spectrometry, and RIP experiments indicated that pyruvate kinase M2 (PKM2) was the direct target of circ_0098181. Circ_0098181 bound to PKM2, restrained its nuclear translocation and phosphorylation.

Conclusion

In conclusion, circ_0098181 exerts a significant anti-fibrotic effect by binding PKM2 to repress its nuclear translocation and inhibiting hepatic inflammation, suggesting the promising therapeutic merit in liver cirrhosis.

Exploring the Role of Ferroptosis-Related Circular RNAs in Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular event associated with high mortality and significant morbidity. Recent studies have highlighted the emerging role of ferroptosis, a novel form of regulated cell death, in the pathogenesis of SAH. Circular RNAs (circRNAs), have been found to play essential roles in various cellular processes, including gene regulation and disease pathogenesis. The expression profile of circRNAs in neural tissues, particularly in the brain, suggests their critical role in synaptic function and neurogenesis. Moreover, the interplay between circRNAs and ferroptosis-related pathways, such as iron metabolism and lipid peroxidation, is explored in the context of SAH. Understanding the functional roles of specific circRNAs in the context of SAH may provide potential therapeutic targets to attenuate ferroptosis-associated brain injury. Furthermore, the potential of circRNAs as diagnostic biomarkers for SAH severity, prognosis, and treatment response is discussed. Overall, this review highlights the significance of studying the intricate interplay between circRNAs and ferroptosis in the context of SAH. Unraveling the mechanisms by which circRNAs modulate ferroptotic cell death may pave the way for the development of novel therapeutic strategies and diagnostic approaches for SAH management, ultimately improving patient outcomes and quality of life.

Circadian rhythm related genes identified through tumorigenesis and immune infiltration-guided strategies as predictors of prognosis, immunotherapy response, and candidate drugs in skin cutaneous malignant melanoma

Background

Skin cutaneous malignant melanoma (SKCM) is among the most aggressive forms of skin cancer, notorious for its rapid progression and poor prognosis under late diagnosis. This study investigates the role of circadian rhythm-related genes (CRGs) in SKCM addressing a gap in understanding how CRGs affect tumor progression and patient outcomes.

Methods

An analysis of CRGs expression was conducted on SKCM samples derived from The Cancer Genome Atlas datasets(TCGA). Moreover, a correlation between various subtypes and their clinical features was identified. The study employed various bioinformatics methods, including differential expression analysis, consensus clustering, and survival analysis, to investigate the role of CRGs. The functional consequences of various CRG expression patterns were further investigated using immune infiltration analysis and gene set variation analysis (GSVA). A scoring system based on CRGs was developed to predict overall survival (OS) and treatment responses in SKCM patients. The predictive accuracy of this score system was then tested, and a nomogram was used to improve its clinical usefulness.

Results

Key findings from this study include significant genetic alterations in circadian rhythm-related genes (CRGs) in skin cutaneous melanoma (SKCM), such as mutations and CNVs. Two molecular subtypes with distinct clinical outcomes and immune profiles were identified. A prognostic model based on six CRGs (CMTM, TNPO1, CTBS, UTRN, HK2, and LIF) was developed and validated with TCGA and GEO datasets, showing high predictive accuracy for overall survival (OS). A high CRGs score correlated with poor OS, immune checkpoint expression, and reduced sensitivity to several chemotherapeutics, including AKT inhibitor VIII and Camptothecin.

Conclusions

This work provides valuable insights into the circadian regulation of SKCM and underscores the potential of CRGs as biomarkers for prognosis and targets for therapeutic interventions. The novel molecular subtypes and CRGs prognostic scoring model introduced in this study offer significant contributions to the understanding and management of SKCM.

Perspectives of exosomal ncRNAs in the treatment of bone metabolic diseases: Focusing on osteoporosis, osteoarthritis, and rheumatoid arthritis

Bone metabolic disorders, constituting a group of prevalent and grave conditions, currently have a scarcity of therapeutic alternatives. Over the recent past, exosomes have been at the forefront of research interest, owing to their nanoparticulate nature and potential for therapeutic intervention. ncRNAs are a class of heterogeneous transcripts that they lack protein-encoding capacity, yet they can modulate the expression of other genes through multiple mechanisms. Mounting evidence underscores the intricate role of exosomes as ncRNAs couriers implicated in the pathogenesis of bone metabolic disorders. In this review, we endeavor to elucidate recent insights into the roles of three ncRNAs - miRNAs, lncRNAs, and circRNAs - in bone metabolic ailments such as osteoporosis, osteoarthritis, and rheumatoid arthritis. Additionally, we examine the viability of exosomal ncRNAs as innovative, cell-free modalities in the diagnosis and therapeutic management of bone metabolic disorders. We aim to uncover the critical function of exosomal ncRNAs within the context of bone metabolic diseases.

LncRNA-MEG3/miR-93-5p/SMAD7 axis mediates proliferative and inflammatory phenotypes of fibroblast-like synoviocytes in rheumatoid arthritis

Synovial hyperplasia, inflammation and immune cell infiltration are the central pathological basis of rheumatoid arthritis (RA). Nonetheless, the cellular, molecular and immunological mechanisms of RA remain poorly understood. An integrated analysis of single-cell RNA (scRNA) and bulk RNA sequencing datasets‌ aimed to unravel the cellular landscape, differentiation trajectory, transcriptome signature, and immunoinfiltration feature of RA synovium. Multilevel experiments were conducted to investigate the role and mechanism of MEG3 in the aggravation and reversal of RA. We screened 97 intergroup differential genes of single-cell transcriptome profiles in the RA versus PsA comparison, which were principally associated with metabolism, inflammation, and proliferation. Clustering and annotation analysis defined 7 key cell subpopulations (monocytes, epithelial cells, CD8+T cells, granulocytes, fibroblasts, HSC_CD34+, and B cells) and their marker genes. Pseudotime analysis demonstrated that fibroblasts could be the end-effector cells, and that downregulation of MEG3 may be responsible for cell differentiation and state transition, followed by the malignant manifestations in the RA synovium. Mechanistically, overexpression of MEG3 could alleviate the proliferative and inflammatory phenotypes of RA synovial fibroblasts by competitively sponging miR-93-5p to promote SMAD7 expression. Taken together, our findings underscore the biological significance of MEG3/miR-93-5p/SMAD7 axis, providing valuable insights into the pathogenesis of RA.

M2 Macrophage-Derived Exosomal circ_0088494 Inhibits Ferroptosis via Promoting H3K4me1 Modification of STEAP3 in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is a common type of cutaneous cancer globally. M2 macrophage-derived exosomes (M2 exosomes) facilitate the development of cancer. Ferroptosis, a newly uncovered form of cell death, is linked to cancer progression. The present research planned to study the function and potential mechanism of M2 exosomes on ferroptosis in cSCC. Patients with cSCC were recruited to gather adjacent noncancerous specimens and cSCC tissues. Mononuclear macrophage (THP-1) cells were differentiated into M2 macrophages before exosome extraction, and then the exosomes were added into cSCC cells (A431 and SCL-1). Erastin was applied to induce ferroptosis. Cell viability, mitochondrial superoxide, lipid-ROS, malondialdehyde (MDA), and iron level were detected to validate ferroptosis in cSCC cells. Proteins and RNAs were tested by applying western blot and RT-qPCR. The combination between molecules was validated by ChIP and RIP. Six-transmembrane epithelial antigen of the prostate 3 (STEAP3) was elevated in cSCC specimens, which correlated to reduced ferroptosis. cSCC tissues presented an increase in the number of M2 macrophages. Erastin-elicited ferroptosis was repressed by M2 macrophages, while exosome inhibitor GW4869 neutralized the outcome of M2 macrophages. Furthermore, M2 exosomes repressed ferroptosis of cSCC cells via circ_0088494, which might be related to the upregulation of STEAP3. M2 exosomes-derived circ_0088494 promoted histone 3 lysine 4 monomethylation (H3K4me1) modification of STEAP3 by recruiting histone-lysine N-methyltransferase 2D (KMT2D). The effect of circ_0088494-silenced M2 exosomes on ferroptosis was antagonized by STEAP3 overexpression. M2 exosomes-derived circ_0088494 recruited KMT2D to promote H3K4me1 modification of STEAP3, thereby inhibiting ferroptosis in cSCC. This study might provide a novel target for cSCC treatment.

N-Acetyltransferase 10 Promotes Gastric Cancer Progression by Mediating the N4-Acetylcytidine Modification of Lactate Dehydrogenase A

The N4-acetylcytidine (ac4C) modification, which is catalyzed by NAT10, represents a significant posttranscriptional modification of mRNA in multiple cancers. However, the significance of this modification in gastric cancer (GC) progression remains unclear. To evaluate the potential of differential NAT10 expression in GC, RT-qPCR and western blot were employed. Dot blot and acRIP were utilized for total ac4C and LDHA mRNA ac4C detection. Subsequently, the effects of NAT10 on GC cell viability and glycolysis were assessed by Cell Counting Kit-8 and glycolysis-related indicator detection Kits. Furthermore, rescue experiments and mice xenograft experiments were conducted to investigate the mechanism underlying the NAT10/LDHA signaling axis in GC. This study identified upregulated NAT10 and ac4C levels in GC. Knockdown of NAT10 led to inhibited cell viability and glycolysis. Additionally, NAT10 directly bound to LDHA mRNA. NAT10 silencing decreased the expression and stability of LDHA mRNA, as well as its ac4C modification level. Interestingly, LDHA overexpression partially reversed the effects of NAT10 knockdown on cell viability and glycolysis. Eventually, the oncogenic effect of NAT10/ac4C/LDHA axis was confirmed in xenograft experiments. NAT10 promoted the GC progression by mediating the ac4C modification of LDHA mRNA, which could serve as a potential therapeutic target for GC.

Role of circRNAs in regulating cell death in cancer: a comprehensive review

Despite multiple diagnostic and therapeutic advances, including surgery, radiation therapy, and chemotherapy, cancer preserved its spot as a global health concern. Prompt cancer diagnosis, treatment, and prognosis depend on the discovery of new biomarkers and therapeutic strategies. Circular RNAs (circRNAs) are considered as a stable, conserved, abundant, and varied group of RNA molecules that perform multiple roles such as gene regulation. There is evidence that circRNAs interact with RNA-binding proteins, especially capturing miRNAs. An extensive amount of research has presented the substantial contribution of circRNAs in various types of cancer. To fully understand the linkage between circRNAs and cancer growth as a consequence of various cell death processes, including autophagy, ferroptosis, and apoptosis, more research is necessary. The expression of circRNAs could be controlled to limit the occurrence and growth of cancer, providing a more encouraging method of cancer treatment. Consequently, it is critical to understand how circRNAs affect various forms of cancer cell death and evaluate whether circRNAs could be used as targets to induce tumor death and increase the efficacy of chemotherapy. The current study aims to review and comprehend the effects that circular RNAs exert on cell apoptosis, autophagy, and ferroptosis in cancer to investigate potential cancer treatment targets.

Circular RNA in Pancreatic Cancer: Biogenesis, Mechanism, Function and Clinical Application

Circular RNAs (circRNAs) are a class of novel RNA molecules featured by single-strand covalently closed circular structure, which not only are extensively found in eukaryotes and are highly conserved, but also conduct paramount roles in the occurrence and progression of pancreatic cancer (PC) through diverse mechanisms. As recent studies have demonstrated, circRNAs typically exhibit tissue-specific and cell specific expression patterns, with strong potential as biomarkers for disease diagnosis and prognosis. On the basis of their localization and specific interactions with DNA, RNA, and proteins, circRNAs are considered to possess specific biological functions by acting as microRNA (miRNA) sponges, RNA binding protein (RBP) sponges, transcriptional regulators, molecular scaffolds and translation templates. On that account, further addressing the technical difficulties in the detection and research of circRNAs and filling gaps in their biological knowledge will definitely push ahead this comparatively young research field and bring circRNAs to the forefront of clinical practice. Thus, this review systematically summarizes the biogenesis, function, molecular mechanisms, biomarkers and therapeutic targets of circRNAs in PC.

circZNF707 promoted glycolysis and tumor progression through miR-668-3p-PFKM axis in NSCLC

BACKGROUND

Circular RNA (circRNA) plays an important regulatory role in the development of human malignancies, but the potential mechanisms of circRNA in non-small cell lung cancer (NSCLC) remain largely unknown.

METHODS

Microarray analysis was used to test for circRNAs differing in expression between NSCLC tumors and healthy adjacent tissues. Using qRT-PCR, the expression of circZNF707 was determined. Through a number of loss-of-function and gain-of-function investigations, the biological behavior of NSCLC cells was evaluated. Finally, tests using Western blotting, RIP, qRT-PCR, and luciferase reporter gene detection and rescue assays revealed the potential mechanism of circZNF707.

RESULTS

Increased expression of circZNF707 was found in NSCLC tissues. Functionally, circZNF707 enhances proliferation, migration, invasion, and glycolysis of NSCLC cells. Mechanistically, circZNF707 can upregulate PFKM by acting as a sponge for miR-668-3p, thus contributing to the progression of NSCLC.

CONCLUSIONS

Through the circZNF707/miR-668-3p/PFKM axis, upregulation of circZNF707 promotes tumor development. CircZNF707 may provide new insights into the treatment and diagnosis of NSCLC.

Targeting ferroptosis in gastrointestinal tumors: Interplay of iron-dependent cell death and autophagy

Ferroptosis is a regulated cell death mechanism distinct from apoptosis, autophagy, and necroptosis, marked by iron accumulation and lipid peroxidation. Since its identification in 2012, it has developed into a potential therapeutic target, especially concerning GI disorders like PC, HCC, GC, and CRC. This interest arises from the distinctive role of ferroptosis in the progression of diseases, presenting a new avenue for treatment where existing therapies fall short. Recent studies emphasize the promise of focusing on ferroptosis to fight GI cancers, showcasing its unique pathophysiological mechanisms compared to other types of cell death. By comprehending how ferroptosis aids in the onset and advancement of GI diseases, scientists aim to discover novel drug targets and treatment approaches. Investigating ferroptosis in gastrointestinal disorders reveals exciting possibilities for novel therapies, potentially revolutionizing cancer treatment and providing renewed hope for individuals affected by these tumors.

Landscape of Noncoding RNA in the Hypoxic Tumor Microenvironment

Amidst the prevalent and notable characteristic of a hypoxic microenvironment present in the majority of solid tumors, a burgeoning number of studies have revealed the significance of noncoding RNAs (ncRNAs) in hypoxic tumor regions. The transcriptome of cancers is highly heterogeneous, with noncoding transcripts playing crucial roles. Long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) are two distinctive classes of ncRNA that are garnering increasing attention. Biologically, they possess intriguing properties and possess significant regulatory functions. Clinically, they present as promising biomarkers and therapeutic targets. Additionally, recent research has evaluated the clinical applications of these ncRNAs in RNA-based treatments and noninvasive liquid biopsies. This review provides a comprehensive summary of recent studies on lncRNAs and circRNAs within the hypoxic tumor microenvironment. Furthermore, the clinical significance of lncRNAs and circRNAs in cancer diagnosis and treatment is emphasized, which could pave the way for the development of effective targeted therapies.

CircRNA circ_0015278 induces ferroptosis in lung adenocarcinoma through the miR-1228/P53 axis

Background

Circular RNAs play an important role in regulating lung adenocarcinoma (LUAD). Bioinformatics analysis identified circ_0015278 as differentially expressed in LUAD. However, the biological mechanism of circ_0015278 in LUAD has not been fully clarified, especially in ferroptosis.

Materials and Methods

Bioinformatics analysis was employed to explore the downstream mechanisms of Circ_0015278, subsequently confirmed by luciferase reporter assays. The impact of Circ_0015278 on cell proliferation, migration, invasion, and ferroptosis was investigated through a loss-of-function experiment. A xenotransplantation mouse model elucidated the effect of Circ_0015278 on tumour growth.

Results

Circ_0015278 exhibited downregulation in LUAD. It inhibited cell proliferation, migration, and invasion while promoting ferroptosis by interacting with miR-1228 to regulate P53 expression through a competitive endogenous RNA mechanism. Moreover, circ_0015278 suppressed tumour growth in mice.

Conclusions

Circ_0015278 was identified as a novel factor promoting ferroptosis in LUAD. Furthermore, it suppressed the malignant progression of LUAD through the miR-1228/P53 axis.

miR-210 Mediated Hypoxic Responses in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one among the most lethal malignancies due to its aggressive behavior and resistance to conventional therapies. Hypoxia significantly contributes to cancer progression and therapeutic resistance of PDAC. microRNAs (miRNAs/miRs) have emerged as critical regulators of various biological processes. miR-210 is known as the "hypoxamir" due to its prominent role in cellular responses to hypoxia. In this study, we investigated the multifaceted role of miR-210 in PDAC using miR-210 knockout (KO) cellular models to elucidate its functions under hypoxic conditions. Hypoxia-inducible factor-1α (HIF1-α), a key transcription factor activated in response to low oxygen levels, upregulates miR-210. miR-210 maintains cancer stem cell (CSC) phenotypes and promotes epithelial-mesenchymal transition (EMT), which is essential for tumor initiation, metastasis, and therapeutic resistance. Our findings demonstrate that miR-210 regulates the expression of CSC markers, such as CD24, CD44, and CD133, and EMT markers, including E-cadherin, Vimentin, and Snail. Specifically, depletion of miR-210 reversed EMT and CSC marker expression levels in hypoxic Panc-1 and MiaPaCa-2 PDAC cells. These regulatory actions facilitate a more invasive and treatment-resistant PDAC phenotype. Understanding the regulatory network involving miR-210 under hypoxic conditions may reveal new therapeutic targets for combating PDAC and improving patient outcomes. Our data suggest that miR-210 is a critical regulator of HIF1-α expression, EMT, and the stemness of PDAC cells in hypoxic environments.

Dysregulated inclusion of BOLA3 exon 3 promoted by HNRNPC accelerates the progression of esophageal squamous cell carcinoma

Dysregulated RNA splicing events produce transcripts that facilitate esophageal squamous cell carcinoma (ESCC) progression, but how this splicing process is abnormally regulated remains elusive. Here, we unveiled a novel alternative splicing axis of BOLA3 transcripts and its regulator HNRNPC in ESCC. The long-form BOLA3 (BOLA3-L) containing exon 3 exhibited high expression levels in ESCC and was associated with poor prognosis. Functional assays demonstrated the protumorigenic function of BOLA3-L in ESCC cells. Additionally, HNRNPC bound to BOLA3 mRNA and promoted BOLA3 exon 3 inclusion forming BOLA3-L. High HNRNPC expression was positively correlated with the presence of BOLA3-L and associated with an unfavorable prognosis. HNRNPC knockdown effectively suppressed the malignant biological behavior of ESCC cells, which were significantly rescued by BOLA3-L overexpression. Moreover, BOLA3-L played a significant role in mitochondrial structural and functional stability. E2F7 acted as a key transcription factor that promoted the upregulation of HNRNPC and inclusion of BOLA3 exon 3. Our findings provided novel insights into how alternative splicing contributes to ESCC progression.

NRF1-induced mmu_circ_0001388/hsa_circ_0029470 confers ferroptosis resistance in ischemic acute kidney injury via the miR-193b-3p/TCF4/GPX4 axis

AIMS

Circular RNAs (circRNAs) are critical in the progression of ischemic acute kidney injury (AKI). Nevertheless, the specific functions and regulatory pathways of mmu_circ_0001388 and hsa_circ_0029470 remain elusive.

METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) was utilized to assess the expression patterns of mmu_circ_0001388, hsa_circ_0029470, and miR-139b-3p. Protein expressions of nuclear respiratory factor 1 (NRF1), transcription factor 4 (TCF4), glutathione peroxidase 4 (GPX4), and Acyl-CoA synthetase long-chain family member 4 (ACSL4) were identified via immunoblotting. Furthermore, the functions and control mechanisms of mmu_circ_003062 and hsa_circ_0075663 were examined via diverse cell and animal studies, encompassing bioinformatics prediction, dual-luciferase reporter (DLR), chromatin immunoprecipitation (ChIP), fluorescence in situ hybridization (FISH), flow cytometry (FCM), hematoxylin and eosin (H&E) staining, dihydroethidium (DHE), TUNEL, immunohistochemistry, and transmission electron microscopy (TEM), and Fe2+ assay.

KEY FINDINGS

Initially, the induction of mmu_circ_0001388 by NRF1 was observed in vitro and in vivo following ischemia/reperfusion (I/R) injury. Subsequently, knockdown or overexpression of mmu_circ_0001388 was found to either promote or inhibit ferroptosis caused by I/R in Boston University mouse proximal tubule (BUMPT) cells, respectively. From a mechanistic standpoint, mmu_circ_0001388 was found to function as a sponge for miR-193b-3p, which promoted TCF4 and subsequently enhanced GPX4, thereby suppressing ferroptosis. Finally, the overexpression of mmu_circ_0001388 was shown to ameliorate I/R-induced AKI in mice. In parallel, hsa_circ_0029470, homologous to mmu_circ_0001388, demonstrated an identical control pathway in human renal tubular epithelial (HK-2) cells.

SIGNIFICANCE

The NRF1/mmu_circ_0001388, hsa_circ_0029470/miR-193b-3p/TCF4/GPX4 axis is pivotal in regulating ferroptosis induced by ischemic AKI and holds potential as a therapeutic target.

miR-5100 Overexpression Inhibits Prostate Cancer Progression by Inducing Cell Cycle Arrest and Targeting E2F7

Despite advances in treatment, prostate cancer remains a leading cause of cancer-related deaths among men, highlighting the urgent need for innovative therapeutic strategies. MicroRNAs (miRNAs) have emerged as key regulatory molecules in cancer biology. In this research, we investigated the tumor-suppressive role of miR-5100 in PCa and its underlying molecular mechanism. By using RT-qPCR, we observed lower miR-5100 expression in PCa cell lines than in benign prostate cells. Functional assays demonstrated that miR-5100 overexpression significantly suppressed PCa cell proliferation, migration, and invasion. By using RNA-sequencing, we identified 446 down-regulated and 806 upregulated candidate miR-5100 target genes overrepresenting cell cycle terms. Mechanistically, E2F7 was confirmed as a direct target of miR-5100 using the reporter gene assay and RIP assay. By conducting flow cytometry analysis, cell cycle progression was blocked at the S phase. E2F7 overexpression partially mitigated the suppressive impact of miR-5100 in PCa cells. In conclusion, miR-5100 is a tumor suppressor in PCa by blocking cell cycle and targeting E2F7.

The crosstalk between alternative splicing and circular RNA in cancer: pathogenic insights and therapeutic implications

RNA splicing is a fundamental step of gene expression. While constitutive splicing removes introns and joins exons unbiasedly, alternative splicing (AS) selectively determines the assembly of exons and introns to generate RNA variants corresponding to the same transcript. The biogenesis of circular RNAs (circRNAs) is inextricably associated with AS. Back-splicing, the biogenic process of circRNA, is a special form of AS. In cancer, both AS and circRNA deviate from the original track. In the present review, we delve into the intricate interplay between AS and circRNAs in the context of cancer. The relationship between AS and circRNAs is intricate, where AS modulates the biogenesis of circRNAs and circRNAs in return regulate AS events. Beyond that, epigenetic and posttranscriptional modifications concurrently regulate AS and circRNAs. On the basis of this modality, we summarize current knowledge on how splicing factors and other RNA binding proteins regulate circRNA biogenesis, and how circRNAs interact with splicing factors to influence AS events. Specifically, the feedback loop regulation between circRNAs and AS events contributes greatly to oncogenesis and cancer progression. In summary, resolving the crosstalk between AS and circRNA will not only provide better insight into cancer biology but also provoke novel strategies to combat cancer.

The splicing factor QKI inhibits metastasis by modulating alternative splicing of E-Syt2 in papillary thyroid carcinoma

Alternative splicing (AS) plays a crucial role in the hallmarks of cancer and can open new avenues for targeted therapies. However, the aberrant AS events and the metastatic cascade in papillary thyroid carcinoma (PTC) remain largely unclear. Here, we identify the splicing factor, quaking protein (QKI), which was significantly downregulated in PTC and correlated with poor survival outcomes in patients with PTC. Functional studies indicated that low expression of QKI promoted the PTC cell growth and metastasis in vitro and in vivo. Mechanistically, low QKI induced exon 14 retention of extended synaptotagmin 2 (E-Syt2) and produced a long isoform transcript (termed E-Syt2L) that acted as an important oncogenic factor of PTC metastasis. Notably, overexpression of long non-coding RNA eosinophil granule ontogeny transcript (EGOT) physically binds to QKI and suppressed its activity by inhibiting ubiquitin specific peptidase 25 (USP25) mediated deubiquitination and subsequent degradation of QKI. Collectively, these data demonstrate the novel mechanistic links between the splicing factor QKI and splicing event in PTC metastasis and support the potential utility of targeting splicing events as a therapeutic strategy for PTC.

Critical role of non-coding RNA-mediated ferroptosis in urologic malignancies

Urologic malignancies, characterized by their high aggressiveness and metastatic potential, pose a significant public health challenge globally. Ferroptosis, a novel mode of cell death, typically arises from intracellular iron ion overload and the accumulation of lipid peroxides. This process has been shown to play a crucial regulatory role in various pathological conditions, particularly in cancer, including urologic cancers. However, the comprehensive regulatory mechanisms underlying ferroptosis remain poorly understood, which somewhat limits its broader application in cancer therapy. Non-coding RNAs (ncRNAs), which encompass microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are non-coding transcripts that play pivotal roles in various physiological processes, such as proliferation, differentiation, apoptosis, and cell cycle regulation, by modulating the expression of target genes. The biological functions and potential regulatory mechanisms of ncRNAs in the context of cancer-related ferroptosis have been partially elucidated. Research indicates that ncRNAs can influence the progression of urologic cancers by affecting cell proliferation, migration, and drug resistance through the regulation of ferroptosis. Consequently, this review aims to clarify the functions and mechanisms of the ncRNA-ferroptosis axis in urologic cancers and to evaluate the clinical significance of ferroptosis-related ncRNAs, thereby providing new insights into cancer biology and therapeutic strategies that may ultimately benefit a diverse range of cancer patients.

CircRNA_SLC8A1 alleviates hypertrophic scar progression by mediating the Nrf2-ARE pathway

BACKGROUND

Hypertrophic scar (HS) is associated with cosmetic defects, mobility, and functional impairments, pruritus, and pain. Previous circRNA microarray analysis identified reduced expression of circRNA_SLC8A1 in HS tissues. Therefore, this study aims to investigate the role of circRNA_SLC8A1 in modulating the abnormal behavior of HS-derived fibroblasts (HSFs) in vitro.

METHODS

RT-qPCR and FISH assays were used to assess the differential expression and localization of circRNA_SLC8A1 in normal and HS tissues. Following modulation of circRNA_SLC8A1 expression, CCK-8, flow cytometry, Transwell, and wound healing assays were employed to evaluate the effects of circRNA_SLC8A1 on the biological behaviors of HSFs. The Starbase database, dual-luciferase reporter assays, and Ago2-RIP assays were utilized to predict and validate the interaction between circRNA_SLC8A1 and downstream miRNAs.

RESULTS

CircRNA_SLC8A1 was found to be downregulated in HS tissues and was primarily localized in the cytoplasm. Overexpression of circRNA_SLC8A1 reduced cell viability, cell invasion, wound healing, and the expression of Vimentin, N-cadherin, Col I, and Col III, while enhancing apoptosis and E-cadherin expression in HSFs. CircRNA_SLC8A1 activates the Nrf2-ARE pathway by competitively binding to miRNA-27a-3p. miRNA-27a-3p and Nrf2 exhibited high and low expression, respectively in HS tissues, with an inverse correlation between their levels. Overexpression of miRNA-27a-3p counteracted the effects of circRNA_SLC8A1 in HSF proliferation, apoptosis, migration, EMT, collagen deposition, and Nrf2-ARE pathway activity.

CONCLUSION

CircRNA_SLC8A1 inhibits the proliferation, migration, EMT, and collagen deposition of HSF through competitive binding with miRNA-27a-3p, thereby activating the Nrf2-ARE pathway. The circRNA_SLC8A1/miRNA-27a-3p/Nrf2-ARE axis may offer a promising molecular target for HS therapy.

The multifaceted role of quaking protein in neuropsychiatric disorders and tumor progression

The Quaking protein (QKI) belongs to the STAR protein family and plays a significant role in the development of the nervous system. It serves as a crucial regulator in the processes of tumor progression and cardiovascular system development. Within the central nervous system, QKI has been associated with the onset and progression of numerous neuropsychiatric disorders, including schizophrenia, depression, ataxia, and Alzheimer's disease. In malignant tumors, the methylation of the QKI promoter inhibits its expression. QKI primarily involves in the generation, stability, and selective splicing of non-coding RNA, as well as in mRNA translation. The role of QKI in the tumor microenvironment should not be overlooked. Especially in Glioblastoma Multiforme (GBM), although QKI is not the primary mutation, it still plays a vital role in maintaining the stemness of GBM. However, the mechanisms and further studies on this topic demand extensive basic and clinical trials.

EIF4A3-mediated oncogenic circRNA hsa_circ_0001165 advances esophageal squamous cell carcinoma progression through the miR-381-3p/TNS3 pathway

Esophageal squamous cell carcinoma (ESCC) remains a major clinical challenge due to its poor prognosis and the scarcity effective therapeutic targets. Circular RNAs (circRNAs) are crucial in cancer progression. In this study, high-throughput sequencing was employed to profile ESCC tissues, revealing that hsa_circ_0001165 is notably elevated in both ESCC tumor samples and cell lines, with its expression is positively associated with patients' TNM staging. Knockdown of hsa_circ_0001165 resulted in reduced malignant biological behavior of ESCC cells in vitro and also inhibited tumor growth in vivo. Mechanism experimental analysis found that hsa_circ_0001165 expression is positively enhanced by eukaryotic translation initiation factor 4A3 (EIF4A3). Hsa_circ_0001165 acts as a miRNA sponge for miR-381-3p, increasing the expression of tensin-3 (TNS3) through a series of related mechanism assays include dual-luciferase reporter gene, RNA Immunoprecipitation and RNA-pulldown. The downregulation in miR-381-3p expression was observed in ESCC tissues, and the cell proliferation, invasion, and migration of ESCC were suppressed. The upregulated expression of hsa_circ_0001165 modulates the miR-381-3p/TNS3 axis and promotes aggressive phenotypes of ESCC. Hsa_circ_0001165 is regarded as a encouraging biomarker and potential therapeutic target for ESCC, presenting innovative options for both diagnostic and treatment approaches.

The role of epigenetics in women's reproductive health: the impact of environmental factors

This paper explores the significant role of epigenetics in women's reproductive health, focusing on the impact of environmental factors. It highlights the crucial link between epigenetic modifications-such as DNA methylation and histones post-translational modifications-and reproductive health issues, including infertility and pregnancy complications. The paper reviews the influence of pollutants like PM2.5, heavy metals, and endocrine disruptors on gene expression through epigenetic mechanisms, emphasizing the need for understanding how dietary, lifestyle choices, and exposure to chemicals affect gene expression and reproductive health. Future research directions include deeper investigation into epigenetics in female reproductive health and leveraging gene editing to mitigate epigenetic changes for improving IVF success rates and managing reproductive disorders.

Hsa_circ_0000520 suppresses vasculogenic mimicry formation and metastasis in bladder cancer through Lin28a/PTEN/PI3K signaling

BACKGROUND

Vasculogenic mimicry (VM) is a potential cause of resistance to antiangiogenic therapy and is closely related to the malignant progression of tumors. It has been shown that noncoding RNAs play an important role in the formation of VM in malignant tumors. However, the role of circRNAs in VM of bladder cancer and the regulatory mechanisms are unclear.

METHODS

Firstly, hsa_circ_0000520 was identified to have circular character by Sanger sequencing and Rnase R assays. Secondly, the potential clinical value of hsa_circ_0000520 was explored by quantitative real-time polymerase chain reaction (qRT-PCR) and fluorescence in situ hybridization (FISH) of clinical specimens. Thirdly, the role of hsa_circ_0000520 in bladder cancer invasion, migration, and VM formation was examined by in vivo and in vitro experiments. Finally, the regulatory mechanisms of hsa_circ_0000520 in the malignant progression of bladder cancer were elucidated by RNA binding protein immunoprecipitation (RIP), RNA pulldown, co-immunoprecipitation (co-IP), qRT-PCR, Western blot (WB), and fluorescence co-localization.

RESULTS

Hsa_circ_0000520 was characterized as a circular RNA and was lowly expressed in bladder cancer compared with the paracancer. Bladder cancer patients with high expression of hsa_circ_0000520 had better survival prognosis. Functionally, hsa_circ_0000520 inhibited bladder cancer invasion, migration, and VM formation. Mechanistically, hsa_circ_0000520 acted as a scaffold to promote binding of UBE2V1/UBC13 to Lin28a, further promoting the ubiquitous degradation of Lin28a, improving PTEN mRNA stability, and inhibiting the phosphorylation of the PI3K/AKT pathway. The formation of hsa_circ_0000520 in bladder cancer was regulated by RNA binding protein QKI.

CONCLUSIONS

Hsa_circ_0000520 inhibits metastasis and VM formation in bladder cancer and is a potential target for bladder cancer diagnosis and treatment.

Research status and potential applications of circRNAs affecting colorectal cancer by regulating ferroptosis

Ferroptosis is an emerging form of non-apoptotic programmed cell death (PCD), characterized by iron-mediated oxidative imbalance. This process plays a significant role in the development and progression of various tumors, including colorectal cancer, gastric cancer, and others. Circular RNA (circRNA) is a stable, non-coding RNA type with a single-stranded, covalently closed loop structure, which is intricately linked to the proliferation, invasion, and metastasis of tumor cells. Recent studies have shown that many circRNAs regulate various pathways leading to cellular ferroptosis. Colorectal cancer, known for its high incidence and mortality among cancers, is marked by a poor prognosis and pronounced chemoresistance. To enhance our understanding of how circRNA-mediated regulation of ferroptosis influences colorectal cancer development, this review systematically examines the mechanisms by which specific circRNAs regulate ferroptosis and their critical role in the progression of colorectal cancer. Furthermore, it explores the potential of circRNAs as biomarkers and therapeutic targets in colorectal cancer treatment, offering a novel approach to clinical management.

Advanced approaches of the use of circRNAs as a replacement for cancer therapy

Cancer is a broad name for a group of diseases in which abnormal cells grow out of control and are characterized by their complexity and recurrence. Although there has been progress in cancer therapy with the entry of precision medicine and immunotherapy, cancer incidence rates have increased globally. Non-coding RNAs in the form of circular RNAs (circRNAs) play crucial roles in the pathogenesis, clinical diagnosis, and therapy of different diseases, including cancer. According to recent studies, circRNAs appear to serve as accurate indicators and therapeutic targets for cancer treatment. However, circRNAs are promising candidates for cutting-edge cancer therapy because of their distinctive circular structure, stability, and wide range of capabilities; many challenges persist that decrease the applications of circRNA-based cancer therapeutics. Here, we explore the roles of circRNAs as a replacement for cancer therapy, highlight the main challenges facing circRNA-based cancer therapies, and discuss the key strategies to overcome these challenges to improve advanced innovative therapies based on circRNAs with long-term health effects.

Circular RNAs in tumor immunity and immunotherapy

Circular RNAs (circRNAs) are unique noncoding RNAs that have a closed and stable loop structure generated through backsplicing. Due to their conservation, stability and tissue specificity, circRNAs can potentially be used as diagnostic indicators and therapeutic targets for certain tumors. Many studies have shown that circRNAs can act as microRNA (miRNA) sponges, and engage in interactions with proteins and translation templates to regulate gene expression and signal transduction, thereby participating in the occurrence and development of a variety of malignant tumors. Immunotherapy has revolutionized the treatment of cancer. Early researches have indicated that circRNAs are involved in regulating tumor immune microenvironment and antitumor immunity. CircRNAs may have the potential to be important targets for increasing sensitivity to immunotherapy and expanding the population of patients who benefit from cancer immunotherapy. However, few studies have investigated the correlation between circRNAs and tumor immunity. In this review, we summarize the current researches on circRNAs involved in antitumor immune regulation through different mechanisms and their potential value in increasing immunotherapy efficacy with the goal of providing new targets for cancer immunotherapy.

Hypoxia exposure induces lactylation of Axin1 protein to promote glycolysis of esophageal carcinoma cells

The hypoxic microenvironment in esophageal carcinoma is an important factor promoting the rapid progression of malignant tumor. This study was to investigate the lactylation of Axin1 on glycolysis in esophageal carcinoma cells under hypoxia exposure. Hypoxia treatment increases pan lysine lactylation (pan-kla) levels of both TE1 and EC109 cells. Meanwhile, ECAR, glucose consumption and lactate production were also upregulated in both TE1 and EC109 cells. The expression of embryonic stem cell transcription factors NANOG and SOX2 were enhanced in the hypoxia-treated cells. Axin1 overexpression partly reverses the induction effects of hypoxia treatment in TE1 and EC109 cells. Moreover, lactylation of Axin1 protein at K147 induced by hypoxia treatment promotes ubiquitination modification of Axin1 protein to promote glycolysis and cell stemness of TE1 and EC109 cells. Mutant Axin1 can inhibit ECAR, glucose uptake, lactate secretion, and cell stemness in TE1 and EC109 cells under normal or hypoxia conditions. Meanwhile, mutant Axin1 further enhanced the effects of 2-DG on inhibiting glycolysis and cell stemness. Overexpression of Axin1 also inhibited tumor growth in vivo, and was related to suppressing glycolysis. In conclusion, hypoxia treatment promoted the glycolysis and cell stemness of esophageal carcinoma cells, and increased the lactylation of Axin1 protein. Overexpression of Axin1 functioned as a glycolysis inhibitor, and suppressed the effects of hypoxia exposure in vitro and inhibited tumor growth in vivo. Mechanically, hypoxia induces the lactylation of Axin1 protein and promotes the ubiquitination of Axin1 to degrade the protein, thereby exercising its anti-glycolytic function.

Baitouweng decoction suppresses growth of esophageal carcinoma cells through miR-495-3p/BUB1/STAT3 axis

BACKGROUND

Esophageal carcinoma (EC) is one of the most prevalent cancers in human populations worldwide. Baitouweng decoction is one of the most important Chinese medicine formulas, with the potential to treat cancer.

AIM

To investigate the role and mechanism of Baitouweng decoction on EC cells.

METHODS

Differentially expressed genes (DEGs) in EC tissues and normal tissues were screened by the cDNA microarray technique and by bioinformatics methods. The target genes of microRNAs were predicted based on the TargetScan database and verified by dual luciferase gene reporter assay. We used Baitouweng decoction to intervene EC cells, and detected the activity of EC9706 and KYSE150 cells by the MTT method. Cell cycle and apoptosis were measured by flow cytometry. The expression of BUB1 mRNA and miR-495-3p was measured by qRT-PCR. The protein levels of BUB1, STAT3, p-STAT3, CCNB1, CDK1, Bax, Caspase3, and Caspase9 were measured by Western blot analysis. The migration and invasion abilities of the cells were measured by wound-healing assay and Transwell invasion assay, respectively.

RESULTS

DEGs identified are involved in biological processes, signaling pathways, and network construction, which are mainly related to mitosis. BUB1 was the key hub gene, and it is also a target gene of miR-495-3p. Baitouweng decoction could upregulate miR-495-3p and inhibit BUB1 expression. In vitro experiments showed that Baitouweng decoction significantly inhibited the migration and invasion of EC cells and induced apoptosis and G2/M phase arrest. After treatment with Baitouweng decoction, the expression of Bax, Caspase 3, and Caspase 9 in EC cells increased significantly, while the expression of BUB1, CCNB1, and CDK1 decreased significantly. Moreover, the STAT3 signaling pathway may play an important role in this process.

CONCLUSION

Baitouweng decoction has a significant inhibitory effect on EC cell growth. BUB1 is a potential therapeutic target for EC. Further analysis showed that Baitouweng decoction may inhibit the growth of EC cells by upregulating miR-495-3p targeting the BUB1-mediated STAT3 signal pathway.

A miR-361-5p/ ORC6/ PLK1 axis regulates prostate cancer progression

Prostate cancer (PCa) is the most prevalent malignant tumor of the genitourinary system, and metastatic disease has a significant impact on the prognosis of PCa patients. As a result, knowing the processes of PCa development can help patients achieve better outcomes. Here, we investigated the expression and function of ORC6 in PCa. Our findings indicated that ORC6 was elevated in advanced PCa tissues. Patients with PCa who exhibited high levels of ORC6 had a poor prognosis. Following that, we investigated the function of ORC6 in PCa progression using a variety of functional experiments both in vivo and in vitro, and discovered that ORC6 knockdown inhibited PCa cell proliferation, growth, and migration. Furthermore, RNA-seq was employed to examine the molecular mechanism of PCa progression. The results revealed that ORC6 might promote the expression of PLK1, a serine/threonine kinase in PCa cells. We also discovered that ORC6 as a novel miR-361-5p substrate using database analysis, and miR-361-5p was found to lower ORC6 expression. Additionally, RNA immunoprecipitation (RIP) and luciferase reporter tests revealed that the transcription factor E2F1 could regulate ORC6 expression in PCa cells. PLK1 overexpression or miR-361-5p inhibitor treatment effectively removed the inhibitory effects caused by ORC6 silencing. Notably, our data showed that therapeutically targeting the miR-361-5p/ORC6/PLK1 axis may be a viable therapy option for PCa.

Exploring the oncogenic potential of circSOD2 in clear cell renal cell carcinoma: a novel positive feedback loop

BACKGROUND

Existing studies have found that circular RNAs (circRNAs) act as sponges for micro RNAs (miRNAs) to control downstream genes. However, the specific functionalities and mechanisms of circRNAs in human clear cell renal cell carcinoma (ccRCC) have yet to be thoroughly investigated.

METHODS

Patient cohorts from online databases were used to screen candidate circRNAs, while another cohort from our hospital was obtained for validation. CircSOD2 was identified as a potential oncogenic target, and its relevant characteristics were investigated during ccRCC progression through various assays. A positive feedback loop containing downstream miRNA and its target gene were identified using bioinformatics and validated by luciferase reporter assays, RNA pull-down, and high-throughput sequencing.

RESULTS

CircSOD2 expression was elevated in tumor samples and significantly correlated with overall survival (OS) and the tumor stage of ccRCC patients, which appeared in the enhanced proliferation, invasion, and migration of tumor cells. Through competitive binding to circSOD2, miR-532-3p can promote the expression of PAX5 and the progression of ccRCC, and such regulation can be salvaged by miR-532-3p inhibitor.

CONCLUSION

A novel positive feedback loop, PAX5/circSOD2/miR-532-3p/PAX5 was identified in the study, indicating that the loop may play an important role in the diagnosis and prognostic prediction in ccRCC patients.

circ_0000592 facilitates the progression of esophageal squamous cell carcinoma via miR-155-5p/FZD5 axis

Esophageal squamous cell carcinoma (ESCC) is one of the gastrointestinal malignancies with high prevalence and poor prognosis. Previous reports suggested that circular ribose nucleic acids might exert regulatory functions in ESCC. This study aims to explore the role of circ_0000592 in ESCC progression, providing novel insights into the diagnosis and therapeutic avenues for ESCC. The GSE131969 data set was utilized to assess circ_0000592 expression in ESCC. The validation was performed in the tumorous tissues of ESCC patients (n = 80) and human-immortalized ESCC cell lines. The correlation between circ_0000592 expression and prognosis was analyzed. The impact of circ_0000592 on ESCC cell activity was evaluated through downregulating circ_0000592, as well as encompassing cell viability, migration, and invasion abilities. The downstream pathway of circ_0000592 was explored by binding site prediction from the TargetScan database, followed by in vitro and in vivo experiments. An in vivo xenograft tumor model was established to highlight the role of circ_0000592 in ESCC. Patients with ESCC exhibited higher circ_0000592 expression levels compared to noncancerous patients, which were associated with reduced survival time, higher TNM stage, and increased lymph node metastasis. The circ_0000592 downregulation suppressed cell viability, migration, and invasion abilities in vitro. Mechanistically, circ_0000592 countered the inhibitory effects on the target gene Frizzled 5 (FZD5) through interactions with miR-155-5p. The overexpression of miR-155-5p curtailed the luciferase activity of circ_0000592 in ESCC cells, inhibiting downstream molecule FZD5 protein expression and subsequently mitigating the detrimental consequences of escalated circ_0000592 expression in ESCC cells. Consistently, circ_0000592 downregulation curbed proliferation and metastasis of ESCC tumors in vivo. In summary, circ_0000592 promoted the progress of ESCC by counteracting the inhibitory impact on FZD5 through its interaction with miR-155-5p. Together, our findings highlighted circ_0000592 as a prospective therapeutic target for ESCC.

Human circular RNA hsa_circ_0000231 clinical diagnostic effectiveness as a new tumor marker in gastric cancer

BACKGROUND

Owing to the subtlety of initial symptoms associated with gastric cancer (GC), the majority of patients are diagnosed at later stages. Given the absence of reliable diagnostic markers, it is imperative to identify novel markers that exhibit high sensitivity and specificity. Circular RNA, a non-coding RNA, plays an important role in tumorigenesis and development and is well expressed in body fluids.

AIMS

In this study, we aimed to identify hsa_circ_0000231 as a new biomarker for the diagnosis of GC and to assess its clinical diagnostic value in serum.

METHODS AND RESULTS

The stability and correctness of hsa_circ_0000231 was determined by agarose gel electrophoresis, Rnase R assay and Sanger sequencing. Real-time quantitative polymerase chain reaction (qRT-PCR) was designed to discover the expression level of hsa_circ_0000231 and whether it has dynamic serum monitoring capability. The correlation between hsa_circ_0000231 and clinicopathological parameters was analyzed by collecting clinical and pathological data from GC patients. In addition, diagnostic efficacy was assessed by constructing receiver operating characteristic curves (ROC). Hsa_circ_0000231 exhibits a stable and consistently expressed structure. In GC serum, cells, and tissues, it demonstrates reduced expression levels. Elevated expression levels observed postoperatively suggest its potential for dynamic monitoring. Additionally its expression level correlates with TNM staging and neuro/vascular differentiation. The area under ROC curve (AUC) for hsa_circ_0000231 is 0.781, indicating its superior diagnostic value compared to CEA, CA19-9, and CA72-4. The combination of these four indicators enhances diagnostic accuracy, with an AUC of 0.833.

CONCLUSIONS

The stable expression of hsa_circ_0000231 in the serum of gastric cancer patients holds promise as a novel biomarker for both the diagnosis and dynamic monitoring of GC.

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.

Potential therapeutic strategy for cancer: Multi-dimensional cross-talk between circRNAs and parental genes

In many ways, circular RNAs (circRNAs) have been demonstrated to be crucial in the onset and advancement of cancer throughout the last ten years and have become a new focus of intense research in the field of RNAs. Accumulating studies have demonstrated that circRNAs can regulate parental gene expression via a variety of biological pathways. Furthermore, research into the complex interactions between circRNAs and their parental genes will shed light on their biological roles and open up new avenues for circRNAs' potential clinical translational uses. However, to date, multi-dimensional cross-talk between circRNAs and parental genes have not been systematically elucidated. Particularly intriguing is circRNA's exploration of tumor targeting, and potential therapeutic uses based on the parental gene regulation perspective. Here, we discuss their biogenesis, take a fresh look at the molecular mechanisms through which circRNAs control the expression of their parental genes in cancer. We further highlight We further highlight the latest circRNA clinical translational applications, including prognostic diagnostic markers, cancer vaccines, gDNA, and so on. Demonstrating the potential benefits and future applications of circRNA therapy.

Deciphering the Role of BCAR3 in Cancer Progression: Gene Regulation, Signal Transduction, and Therapeutic Implications

This review comprehensively explores the gene BCAR3, detailing its regulation at the gene, mRNA, and protein structure levels, and delineating its multifunctional roles in cellular signaling within cancer contexts. The discussion covers BCAR3's involvement in integrin signaling and its impact on cancer cell migration, its capability to induce anti-estrogen resistance, and its significant functions in cell cycle regulation. Further highlighted is BCAR3's modulation of immune responses within the tumor microenvironment, a novel area of interest that holds potential for innovative cancer therapies. Looking forward, this review outlines essential future research directions focusing on transcription factor binding studies, isoform-specific expression profiling, therapeutic targeting of BCAR3, and its role in immune cell function. Each segment builds towards a holistic understanding of BCAR3's operational mechanisms, presenting a critical evaluation of its therapeutic potential in oncology. This synthesis aims to not only extend current knowledge but also catalyze further research that could pivotally influence the development of targeted cancer treatments.

Ferroptosis and circular RNAs: new horizons in cancer therapy

Cancer poses intricate challenges to treatment due to its complexity and diversity. Ferroptosis and circular RNAs (circRNAs) are emerging as innovative therapeutic avenues amid the evolving landscape of cancer therapy. Extensive investigations into circRNAs reveal their diverse roles, ranging from molecular regulators to pivotal influencers of ferroptosis in cancer cell lines. The results underscore the significance of circRNAs in modulating molecular pathways that impact crucial aspects of cancer development, including cell survival, proliferation, and metastasis. A detailed analysis delineates these pathways, shedding light on the molecular mechanisms through which circRNAs influence ferroptosis. Building upon recent experimental findings, the study evaluates the therapeutic potential of targeting circRNAs to induce ferroptosis. By identifying specific circRNAs associated with the etiology of cancer, this analysis paves the way for the development of targeted therapeutics that exploit vulnerabilities in cancer cells. This review consolidates the existing understanding of ferroptosis and circRNAs, emphasizing their role in cancer therapy and providing impetus for ongoing research in this dynamic field. See also the graphical abstract(Fig. 1).

BMSC-derived Exosomes Ameliorate Peritoneal Dialysis-associated Peritoneal Fibrosis via the Mir-27a-3p/TP53 Pathway

OBJECTIVE

Peritoneal fibrosis (PF) is the main cause of declining efficiency and ultrafiltration failure of the peritoneum, which restricts the long-term application of peritoneal dialysis (PD). This study aimed to investigate the therapeutic effects and mechanisms of bone marrow mesenchymal stem cells-derived exosomes (BMSC-Exos) on PF in response to PD.

METHODS

Small RNA sequencing analysis of BMSC-Exos was performed by second-generation sequencing. C57BL/6J mice were infused with 4.25% glucose-based peritoneal dialysis fluid (PDF) for 6 consecutive weeks to establish a PF model. A total of 36 mice were randomly divided into 6 groups: control group, 1.5% PDF group, 2.5% PDF group, 4.25% PDF group, BMSC-Exos treatment group, and BMSC-Exos+TP53 treatment group. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to measure the expression level of miR-27a-3p in BMSC-Exos and peritoneum of mice treated with different concentrations of PDF. HE and Masson staining were performed to evaluate the extent of PF. The therapeutic potential of BMSC-Exos for PF was examined through pathological examination, RT-qPCR, Western blotting, and peritoneal function analyses. Epithelial-mesenchymal transition (EMT) of HMrSV5 was induced with 4.25% PDF. Cells were divided into control group, 4.25% PDF group, BMSC-Exos treatment group, and BMSC-Exos+TP53 treatment group. Cell Counting Kit-8 assay was used to measure cell viability, and transwell migration assay was used to verify the capacity of BMSC-Exos to inhibit EMT in HMrSV5 cells.

RESULTS

Small RNA sequencing analysis showed that miR-27a-3p was highly expressed in BMSC-derived exosomes compared to BMSCs. The RT-qPCR results showed that the expression of miR-27a-3p was upregulated in BMSC-Exos, but decreased in PD mice. We found that PF was glucose concentration-dependently enhanced in the peritoneum of the PD mice. Compared with the control mice, the PD mice showed high solute transport and decreased ultrafiltration volume as well as an obvious fibroproliferative response, with markedly increased peritoneal thickness and higher expression of α-SMA, collagen-I, fibronectin, and ECM1. The mice with PD showed decreased miR-27a-3p. Peritoneal structural and functional damage was significantly attenuated after BMSC-Exos treatment, while PF and mesothelial damage were significantly ameliorated. Additionally, markers of fibrosis (α-SMA, collagen-I, fibronectin, ECM1) and profibrotic cytokines (TGF-β1, PDGF) were downregulated at the mRNA and protein levels after BMSC-Exos treatment. In HMrSV5 cells, BMSC-Exos reversed the decrease in cell viability and the increase in cell migratory capacity caused by high-glucose PDF. Western blotting and RT-qPCR analysis revealed that BMSC-Exos treatment resulted in increased expression of E-cadherin (epithelial marker) and decreased expression of α-SMA, Snail, and vimentin (mesenchymal markers) compared to those of the 4.25% PDF-treated cells. Importantly, a dual-luciferase reporter assay showed that TP53 was a target gene of miR-27a-3p. TP53 overexpression significantly reversed the decreases in PF and EMT progression induced by BMSC-Exos.

CONCLUSION

The present results demonstrate that BMSC-Exos showed an obvious protective effect on PD-related PF and suggest that BMSC-derived exosomal miR-27a-3p may exert its inhibitory effect on PF and EMT progression by targeting TP53.

Circular RNAs in glioma: Molecular functions and pathological implications

Circular RNAs (circRNAs) are a special class of non-coding RNAs with the ring structure. They are stable, abundant and conservative across mammals. The biogenesis and molecular properties of circRNAs are being elucidated, which exert regulatory functions not only through miRNA and protein sponge, but also via translation and exosomal interaction. Accumulating studies have demonstrated that circRNAs are aberrantly expressed in various diseases, especially in cancer. Glioma is one of the most common malignant cerebral neoplasms with poor prognosis. The accurate diagnosis and effective therapies of glioma have always been challenged, there is an urgent need for developing promising therapeutic intervention. Therefore, exploring novel biomarkers is crucial for diagnosis, treatment and prognosis of the glioma which can provide better assistance in guiding treatment. Recent findings found that circRNAs are systematically altered in glioma and may play critical roles in glioma tumorigenesis, proliferation, invasion and metastasis. Due to their distinct functional properties, they are considered as the potential therapeutic targets, diagnostic and prognostic biomarkers. This review elaborates on current advances towards the biogenesis, translation and interaction of circRNAs in many diseases and focused on the role of their involvement in glioma progression, highlighting the potential value of circRNAs in glioma.

Ferroptosis: Potential opportunities for natural products in cancer therapy

Cancer cells often exhibit defects in the execution of cell death, resulting in poor clinical outcomes for patients with many cancer types. Ferroptosis is a newly discovered form of programmed cell death characterized by intracellular iron overload and lipid peroxidation in the cell membrane. Increasing evidence suggests that ferroptosis is closely associated with a wide variety of physiological and pathological processes, particularly in cancer. Notably, various bioactive natural products have been shown to induce the initiation and execution of ferroptosis in cancer cells, thereby exerting anticancer effects. In this review, we summarize the core regulatory mechanisms of ferroptosis and the multifaceted roles of ferroptosis in cancer. Importantly, we focus on natural products that regulate ferroptosis in cancer cells, such as terpenoids, polyphenols, alkaloids, steroids, quinones, and polysaccharides. The clinical efficacy, adverse effects, and drug-drug interactions of these natural products need to be evaluated in further high-quality studies to accelerate their application in cancer treatment.

Wnt/β-catenin-driven EMT regulation in human cancers

Metastasis accounts for 90% of cancer-related deaths among the patients. The transformation of epithelial cells into mesenchymal cells with molecular alterations can occur during epithelial-mesenchymal transition (EMT). The EMT mechanism accelerates the cancer metastasis and drug resistance ability in human cancers. Among the different regulators of EMT, Wnt/β-catenin axis has been emerged as a versatile modulator. Wnt is in active form in physiological condition due to the function of GSK-3β that destructs β-catenin, while ligand-receptor interaction impairs GSK-3β function to increase β-catenin stability and promote its nuclear transfer. Regarding the oncogenic function of Wnt/β-catenin, its upregulation occurs in human cancers and it can accelerate EMT-mediated metastasis and drug resistance. The stimulation of Wnt by binding Wnt ligands into Frizzled receptors can enhance β-catenin accumulation in cytoplasm that stimulates EMT and related genes upon nuclear translocation. Wnt/β-catenin/EMT axis has been implicated in augmenting metastasis of both solid and hematological tumors. The Wnt/EMT-mediated cancer metastasis promotes the malignant behavior of tumor cells, causing therapy resistance. The Wnt/β-catenin/EMT axis can be modulated by upstream mediators in which non-coding RNAs are main regulators. Moreover, pharmacological intervention, mainly using phytochemicals, suppresses Wnt/EMT axis in metastasis suppression.

Hypoxia increases the biogenesis of IGF2BP3-bound circular RNAs

BACKGROUND

Insulin-like Growth Factor 2 Binding Protein 3 (IGF2BP3) promotes cancer migration and invasion by binding to several coding and non-coding RNAs. Hypoxia stimulates tumor progression by upregulating Hypoxia Inducible Factors and downstream signaling. Quaking (QKI) gene, which is upregulated in hypoxia and promotes epithelial to mesenchymal transition (EMT), induces circular RNAs. Therefore, the axis between IGF2BP3, QKI, circular RNAs and their respective host genes under hypoxia was studied.

METHODS AND RESULTS

Several IGF2BP3-bound circular RNAs were previously identified in HepG2. There were 13 circRNAs originating from 8 host genes bound to IGF2BP3. We confirmed their binding to IGF2BP3 in U87MG using an RNA Immunoprecipitation assay. MALAT1, an oncogenic lncRNA was also found to be associated with IGF2BP3. Three adherent cell lines expressing high levels of IGF2BP3 viz., HeLa, HepG2 and U87MG were cultured under normoxia (20%O2) and hypoxia (<0.2%O2) for 48-168 h. Expression of IGF2BP3, QKI, EMT markers, IGF2BP3-bound circRNAs and their host mRNAs expression were assessed by quantitative real-time PCR (qRT-PCR) in both normoxia and hypoxia. The hypoxia markers viz., VEGF and CA9 were upregulated in all the cell lines in hypoxia at all time points along with an increase in SNAIL. We found 6 genes, viz., PHC3, CDYL, ANKRD17, ARID1A, NEIL3 and FNDC3B with increased expression both at the mRNA and circRNA level indicating their synergistic role in tumor initiation. Overall, we found that circRNA to mRNA expression was observed to be increased for most of the genes and time points of hypoxia in all the cell lines. IGF2BP3 and QKI were also upregulated in hypoxia indicating their role in circRNA biogenesis and stability.

CONCLUSION

Our data implies that hypoxia augments circRNA biogenesis which might subsequently play a role in tumor progression.