circNDUFB2 inhibits non-small cell lung cancer progression via destabilizing IGF2BPs and activating anti-tumor immunity

CircATP5C1 promotes triple-negative breast cancer progression by binding IGF2BP2 to modulate CSF-1 secretion

Triple-negative breast cancer (TNBC) is a common malignant disease among females and severely threatens the health of women worldwide. Nowadays, circular RNAs (circRNAs) aroused our interest for their functions in human cancers, including TNBC. However, the mechanism of most circRNAs in the progression of TNBC remains unclear. We found a novel circRNA named circATP5C1, whose function in TNBC remains uncovered. Tissue microarray was used to analyze the association between the expression of circATP5C1 and the prognoses of TNBC patients. Gain-and loss-of-function experiments were performed to validate the biological functions of circATP5C1 in different TNBC cell lines. RNA-seq analyses were conducted to find out the target genes regulated by circATP5C1. RNA pull-down assay and mass spectrometry were used to select the proteins associated with circATP5C1. RNA FISH-immunofluorescence and RNA immunoprecipitation (RIP) were complemented to validate the interaction between circATP5C1 and its binding protein. CircATP5C1 was identified to have predictive function in prognosis of TNBC patients. CircATP5C1 advanced the progression of TNBC cells. Mechanistically, Colony stimulating factor 1 (CSF-1) is a vital downstream gene regulated by circATP5C1. The alteration of CSF-1 expression level was validated due to the interaction between circATP5C1 and insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2). Rescue experiments demonstrated that circATP5C1 accelerates the progression of TNBC partly via binding with IGF2BP2 to increase the secretion of CSF-1. This study uncovers a novel mechanism of circATP5C1/IGF2BP2/CSF-1 pathway in regulating progression of TNBC.

Expanded insights into the mechanisms of RNA-binding protein regulation of circRNA generation and function in cancer biology and therapy

RNA-binding proteins (RBPs) regulate the generation of circular RNAs (circRNAs) by participating in the reverse splicing of circRNA and thereby influencing circRNA function in cells and diseases, including cancer. Increasing evidence has demonstrated that the circRNA-RBP network plays a complex and multifaceted role in tumor progression. Thus, a better understanding of this network may provide new insights for the discovery of cancer drugs. In this review, we discuss the characteristics of RBPs and circRNAs and how the circRNA-RBP network regulates tumor cell phenotypes such as proliferation, metastasis, apoptosis, metabolism, immunity, drug resistance, and the tumor environment. Moreover, we investigate the factors that influence circRNA-RBP interactions and the regulation of downstream pathways related to tumor development, such as the tumor microenvironment and N6-methyladenosine modification. Furthermore, we discuss new ideas for targeting circRNA-RBP interactions using various RNA technologies.

RNA methylation: A new promising biomaker in cancer liquid biopsy

RNA methylation is a vital epigenetic modification that regulates gene expression by influencing RNA processes such as transcription, degradation, translation, and transport. Aberrant methylation, including modifications like m6A, m5C, m1A, m7G, and m3C, is closely linked to tumorigenesis and progression. Liquid biopsy, a non-invasive technique analyzing tumor markers in body fluids, offers significant potential for early diagnosis and dynamic monitoring. In this context, RNA methylation, due to its tumor-specific properties, is emerging as a valuable marker. However, significant challenges remain in its clinical application. This review explores the roles of RNA methylation in cancer, recent advances in detection technologies, and its potential as a liquid biopsy marker in tumor management. It highlights its promising applications in cancer diagnosis, prognosis, and personalized treatment in the era of precision oncology.

Advances in molecular pathology and therapy of non-small cell lung cancer

Over the past two decades, non-small cell lung cancer (NSCLC) has witnessed encouraging advancements in basic and clinical research. However, substantial unmet needs remain for patients worldwide, as drug resistance persists as an inevitable reality. Meanwhile, the journey towards amplifying the breadth and depth of the therapeutic effect requires comprehending and integrating diverse and profound progress. In this review, therefore, we aim to comprehensively present such progress that spans the various aspects of molecular pathology, encompassing elucidations of metastatic mechanisms, identification of therapeutic targets, and dissection of spatial omics. Additionally, we also highlight the numerous small molecule and antibody drugs, encompassing their application alone or in combination, across later-line, frontline, neoadjuvant or adjuvant settings. Then, we elaborate on drug resistance mechanisms, mainly involving targeted therapies and immunotherapies, revealed by our proposed theoretical models to clarify interactions between cancer cells and a variety of non-malignant cells, as well as almost all the biological regulatory pathways. Finally, we outline mechanistic perspectives to pursue innovative treatments of NSCLC, through leveraging artificial intelligence to incorporate the latest insights into the design of finely-tuned, biomarker-driven combination strategies. This review not only provides an overview of the various strategies of how to reshape available armamentarium, but also illustrates an example of clinical translation of how to develop novel targeted drugs, to revolutionize therapeutic landscape for NSCLC.

A novel peptide MIB1-223aa encoded by exosomal circMIB1 from cancer-associated fibroblasts drives triple-negative breast cancer metastasis and stemness via stabilizing MIB1 to activate Notch signaling

INTRODUCTION

Emerging evidence has indicated that the complex interactions between tumor microenvironment (TME) and cancer cells play a pivotal role in driving tumor initiation and metastasis. Cancer associated fibroblasts (CAFs), major cell components in the TME, exert significant effects on malignant behaviors of various cancers. Triple negative breast cancer (TNBC) is the most malignant subtype of breast cancer with a high metastatic potential and poorer prognosis. However, the underlying mechanism by which CAFs promote TNBC development has not been sufficiently studied.

OBJECTIVES

The study aims to elucidate how CAFs promote TNBC aggressiveness by delivering protein-coding circMIB1 to activate MIB1/DLL4/Notch pathway, and provide a potential clinical biomarker for TNBC management.

METHODS

The oncogenic exosomal circMIB1 with protein-coding potential was identified through high-throughput RNA sequencing and ribosome nascent-chain complex sequencing (RNC-seq). The enrichment of circMIB1 in CAFs was confirmed using in situ hybridization (ISH) and qRT-PCR. The protein-coding capacity of circMIB1 was validated based on the polysome profiling, and luciferase assays. Functional roles of circMIB1 were explored using in vitro and in vivo models, while the underlying mechanism was dissected via co-immunoprecipitation (Co-IP) and western blotting.

RESULTS

CAF-secreted exosomal circMIB1 promoted TNBC metastasis and stemness by translating a functional peptide, MIB1-223aa. Mechanistically, MIB1-223aa competitively bound to the E3 ubiquitin ligase RNF213, which blocked the RNF213-mediated K48-linked ubiquitination and degradation of MIB1. Moreover, the stabilized MIB1 enhanced the Notch signaling via a ubiquitination-dependent activation of the ligand DLL4, thereby driving TNBC malignancy. Clinically, high expression of circMIB1 or MIB1-223aa in TNBC tissues was correlated with poor clinical prognosis, as evidenced by reduced overall survival, shortened disease-free survival, and elevated lymphatic metastasis rates.

CONCLUSION

This study provides the first evidence of exosome-transmitted protein-coding circRNAs in CAF-TNBC crosstalk, offering novel insights into the TME-driven metastasis and providing promising biomarker for TNBC management.

CircSLC22A3 inhibits the invasion and metastasis of ESCC via the miR-19b-3p/TRAK2 axis and by reducing the stability of m6A-modified ACSBG1 mRNA

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a major contributor to cancer-related deaths, driven by its invasive and metastatic nature. Circular RNAs (circRNAs) are increasingly recognized as regulators of cancer progression, primarily through miRNA sponging and interactions with RNA-binding proteins. Their dysregulation has been linked to the development of in various cancers. The present study aimed to investigate the potential involvement of circSLC22A3 in the pathogenesis of ESCC.

METHODS

CircSLC22A3 expression in ESCC tissues and cells was analyzed using transcriptome sequencing and RT-qPCR. Its circular structure was validated through Sanger sequencing, agarose gel electrophoresis, RNase R digestion, and random priming assays. Subcellular localization was determined by nucleoplasmic separation and fluorescence in situ hybridization (FISH). Clinical correlations were assessed via tissue microarrays. Functional roles of circSLC22A3 in ESCC progression were investigated through in vitro and in vivo assays. Downstream miR-19b-3p and target gene TRAK2 were screened by bioinformatics analysis and RT-qPCR, with binding confirmed via luciferase reporter assays. RNA pulldown combined with RNA immunoprecipitation (RIP) identified IGF2BP1 as a circSLC22A3-interacting protein. RNA-seq and RT-qPCR revealed ACSBG1 as a key downstream effector. IGF2BP1-mediated m6A modification of ACSBG1 was mapped by MeRIP-seq and RIP, with mRNA stability assessed via Actinomycin D assay. ACSBG1 expression and biological function in ESCC were confirmed by immunohistochemistry, RT-qPCR, and functional assays.

RESULTS

Significant downregulation of circSLC22A3 was observed in both ESCC tissues and cell lines. Overexpression of circSLC22A3 significantly reduced ESCC cells' migration and invasion capabilities. Mechanistic investigation revealed that circSLC22A3 played a pivotal role in the invasion and metastasis of esophageal cancer through distinct pathways. On one hand, circSLC22A3 functioned as a miR-19b-3p sponge to augment trafficking kinesin protein 2 (TRAK2) expression, while, on the other hand, circSLC22A3 formed a protein-RNA complex with IGF2BP1, resulting in the degradation of acyl-CoA synthetase bubblegum family member 1 (ACSBG1) mRNA through the recognition of m6A modification, thereby suppressing invasion and metastasis of ESCC.

CONCLUSIONS

The present study identified circSLC22A3 as a new tumor suppressor that inhibited ESCC progression through both the circSLC22A3/ miR-19b-3p/ TRAK2 and circSLC22A3/ IGF2BP1/ ACSBG1 axes.

Reciprocal regulation between m6 A modifications and non-coding RNAs: emerging roles in cancer therapeutic resistance

In recent years, the interplay between N6-methyladenosine (m6A) modifications and non-coding RNAs (ncRNAs) has emerged as a pivotal research area, owing to their crucial involvement in the pathophysiological mechanisms underlying various diseases. A significant hurdle in cancer therapy is therapeutic resistance, which frequently contributes to adverse patient outcomes. Recent investigations have underscored the vital role that interactions between m6A modifications and ncRNAs play in mediating cancer therapeutic resistance via the MAPK, PI3K/Akt/mTOR, Wnt/β-catenin, HIPPO, and NF-κB pathways. This review elucidates how these interactions drive tumor therapeutic resistance by modulating these pathways. By dissecting the regulatory dynamics between m6A and ncRNAs in the context of cancer therapeutic resistance, this review aims to deepen the understanding of m6A-ncRNA interaction in cancer therapeutic resistance and identify potential therapeutic targets to improve cancer treatment efficacy.

Circ_0002638 drives squamous cell lung cancer (LUSC) progression and chemotherapy resistance by inhibiting ferroptosis via SENP1-mediated deSUMOylation of ACSL4

AIMS

Chemotherapy is the first-line treatment for LUSC, but chemotherapy resistance often leads to tumor recurrence, significantly affecting the prognosis of patients. We sought to investigate the potential involvement of circRNAs in chemotherapy-resistant LUSC.

MAIN METHODS

qRT-PCR and circRNA sequencing were employed to assess the level of circRNAs in LUSC patients treated with chemotherapy, and the role of circ_0002638 in LUSC was explored in vivo and in vitro. RNA pulldown, mass spectrometry, and co-IP assays were performed to evaluate the underlying mechanism by which circ_0002638 promotes the progression of LUSC.

KEY FINDINGS

The expression of circ_0002638 is significantly upregulated in LUSC patients with PD (progressive disease) compared to those with PR (partial remission) after chemotherapy. Furthermore, upregulation of circ_0002638 enhanced the tumor progression. Mechanistically, circ_0002638 acts as a scaffold promoting the binding of SENP1 to ACSL4 and facilitates the process of deSUMOylation of ACSL4 was shown to protect LUSC from ferroptosis. Importantly, a combination of SENP1-IN-1 with chemotherapy has a synergistic effect in inhibiting tumor growth.

SIGNIFICANCE

This study offers novel perspectives on the function of circ_0002638 in LUSC, and provided a therapeutic target to enhance the chemotherapy sensitivity of LUSC.

Tumor cell-intrinsic circular RNA circFNDC3B attenuates CD8+ T cells infiltration in non-small cell lung cancer

Tumor-infiltrating CD8+ T cells are critical for anti-tumor immunity and positively associated with patient survival. However, the mechanisms governing CD8+ T cell infiltration remain incompletely elucidated, particularly those involving circular RNAs (circRNAs). In this study, we characterized circRNA expression profiles in four paired normal and tumor tissues of non-small-cell lung cancer (NSCLC) and identified that circFNDC3B, a circular transcript derived from exons 2 and 3 of the fibronectin type III domain containing 3B (FNDC3B) gene, as significantly upregulated in NSCLC tissues. Mechanistic investigations revealed that circFNDC3B directly binds to transcription factor II-I (TFII-I), forming an RNA-protein complex that competitively disrupts the interaction between TFII-I and STAT1. This sequestration abrogates the transcriptional activation of CXCL10 and CXCL11, two critical chemokines governing CD8+ T cell chemoattraction. Consequently, reduced CXCL10/11 expression significantly impairs CD8+ T cell infiltration into the tumor microenvironment. Consistently, the murine ortholog circFndc3b expression exhibits an inverse correlation with CD8+ T cell infiltration in tumors. Our study uncovers a crucial circRNA-mediated regulatory axis wherein circFNDC3B impedes anti-tumor immunity by suppressing chemokine-dependent CD8+ T cell recruitment, positioning circFNDC3B as a potential therapeutic target to enhance CD8+ T cell-mediated anti-tumor responses in NSCLC.

LncRNA HOTAIR Interaction With WTAP Promotes m6A Methyltransferase Complex Assembly and Posterior Capsule Opacification Formation by Increasing THBS1

Purpose

To explore the role of long non-coding RNAs (lncRNAs) and N6-methyladenosine (m6A) in posterior capsule opacification (PCO) and their underlying mechanisms.

Methods

The localization of lncRNAs and proteins was analyzed using fluorescence in situ hybridization and immunofluorescence staining. RNA m6A quantification, RNA immunoprecipitation, co-immunoprecipitation, MeRIP-seq, MeRIP-qPCR, western blotting, wound healing, and Transwell assays were applied to elucidate the underlying mechanisms.

Results

The levels of lncRNA HOX transcript antisense intergenic RNA (HOTAIR) and m6A methylation increased significantly during epithelial-mesenchymal transition (EMT) in lens epithelial cells (LECs). HOTAIR promoted EMT and m6A methyltransferase activity but had no effect on methyltransferase activity and was not modified by m6A. Nevertheless, HOTAIR interacted with WT1-associated protein (WTAP), a key m6A writer protein, facilitating WTAP-mediated recruitment of METTL3-METTL14 heterodimers and enhancing m6A modification. The HOTAIR/WTAP complex elevated m6A levels, thrombospondin 1 (THBS1) expression, and EMT in LECs.

Conclusions

LncRNA HOTAIR enhances the assembly of the WTAP/METTL3/METTL14 complex and promotes EMT in LECs by upregulating m6A modification and THBS1 expression. Targeting the HOTAIR/WTAP/THBS1 pathway may prevent or treat PCO.

NSUN2-mediated m5C modification of circFAM190B promotes lung cancer progression by inhibiting cellular autophagy

5-Methylcytosine (m5C) modification is an important type of RNA methylation. Diverse noncoding RNAs can undergo m5C modification and play important roles in tumour development, but circRNA m5C modifications have not been fully revealed in tumours. Here, circFAM190B, which was significantly overexpressed in lung cancer cells and tissues, was identified by constructing a differential expression profile of m5C-modified circRNAs. circFAM190B was found to be associated with lung cancer stage and prognosis. Moreover, we proposed the novel hypothesis that NSUN2 can mediate circFAM190B m5C modification and enhance circFAM190B stability in an m5C-dependent manner. We also clarified the biological function of circFAM190B in significantly promoting the development of lung cancer. Mechanistically, circFAM190B targets SFN and regulates its ubiquitination, thereby inhibiting cellular autophagy through the SFN/mTOR/ULK1 pathway and ultimately promoting lung cancer development. This study reveals the existence of m5C modification of circRNAs, and circRNAs modified by m5C can play important roles in the development of lung cancer, which provides a new theoretical basis for elucidating the molecular mechanism of lung cancer development.

Acetylated KIAA1429 by TIP60 facilitates metastasis and immune evasion of hepatocellular carcinoma via N6-methyladenosine-KDM5B-mediated regulation of FoxO1

Hepatocellular carcinoma (HCC) is characterized by programmed cell death ligand-1 (PD-L1)-mediated immune escape. This study aimed to elucidate the function and mechanism behind KIAA1429, a component of N6-methyladenosine (m6A) complex, in immune escape of HCC. PD-L1 expression was assessed through immunofluorescence staining, and flow cytometry was used to determine CD8+ T cell percentage. The level of IFN-γ was detected using enzyme-linked immunosorbent assay. Cell proliferation, migration, and invasion were evaluated through CCK-8, colony formation, and Transwell assays, respectively. The m6A modification level was measured using an RNA methylation quantification assay, m6A dot blot, and methylated RNA immunoprecipitation-qPCR. Molecule interaction was validated using RNA pulldown, RNA immunoprecipitation, chromatin immunoprecipitation, and co-immunoprecipitation assays. In vivo HCC growth was evaluated in NOD/SCID mice. We found that TIP60, KIAA1429 and KDM5B were highly expressed in HCC cells, while FoxO1 was poorly expressed. Functionally, TIP60/KIAA1429 silencing inhibited PD-L1-mediated HCC immune evasion, growth, migration, and invasion. Mechanistically, TIP60 led to acetylation of KIAA1429, which promoted KDM5B expression in an m6A-YTHDF1-dependent manner, and subsequently restrained the transcription and expression of FoxO1. Enforcing YTHDF1 expression or depleting FoxO1 expression markedly reversed the suppressive effect of shKIAA1429 on HCC immune evasion, growth, migration, and invasion. Overall, these findings suggest that acetylated KIAA1429-mediated m6A modification endows HCC cells with immune evasion through regulation of KDM5B/FoxO1 axis, which provide a treatment option for HCC by targeting KIAA1429.

QKI-induced circ_0001766 inhibits colorectal cancer progression and rapamycin resistance by miR-1203/PPP1R3C/mTOR/Myc axis

Colorectal cancer (CRC) is the third most common cancer and remains a significant challenge due to high rates of drug resistance and limited therapeutic options. Circular RNAs (circRNAs) are increasingly recognized for their roles in CRC initiation, progression, and drug resistance. However, no circRNA-based therapies have yet entered clinical development, underscoring the need for comprehensive detection and mechanistic studies of circRNAs in CRC. Here, we identified and characterized a circular RNA, circ_0001766 (hsa_circ_0001766), through microarray analysis of CRC tissues. Our results showed that circ_0001766 is downregulated in CRC tissues and closely associated with patient survival and metastasis. Functional experiments demonstrated that circ_0001766 inhibits CRC cell proliferation, migration and invasion both in-vitro and in-vivo. Mechanistically, hypoxia downregulates Quaking (QKI), an RNA-binding protein essential for the biogenesis of circ_0001766 by binding to introns 1 and 3 of PDIA4 pre-mRNA. Reduced QKI expression under hypoxic conditions leads to decreased circ_0001766 levels in CRC. Circ_0001766 acts as a competitive endogenous RNA, sponging miR-1203 to prevent the degradation of PPP1R3C mRNA. Loss of circ_0001766 results in decreased PPP1R3C expression, leading to the activation of mTOR signaling and increased phosphorylation of Myc, which promotes CRC progression and rapamycin resistance. Our study reveals that overexpression of circ_0001766 or PPP1R3C in CRC cells inhibits the mTOR and Myc pathway, thereby resensitizing cells to rapamycin. The combination of circ_0001766 or PPP1R3C with rapamycin markedly inhibits CRC cell proliferation and induces apoptosis by reducing rapamycin-induced Myc phosphorylation. In summary, our study elucidates a critical circ_0001766/miR-1203/PPP1R3C axis that modulates CRC progression and rapamycin resistance. Our findings highlight circ_0001766 as a promising therapeutic target in CRC, providing a new avenue for enhancing the efficacy of existing treatments and overcoming drug resistance.

The role of circular RNA in immune response to tuberculosis and its potential as a biomarker and therapeutic target

Circular RNA (circRNA) is a new type of non-coding RNA that has gained significant attention in recent years, especially in tuberculosis research. Tuberculosis poses a major global public health threat. Its complex pathological mechanisms and worsening drug resistance urgently necessitate new research breakthroughs. The role of circRNA in mycobacterium tuberculosis infection is being gradually revealed, highlighting its importance in regulating gene expression, immune response, and inflammation. Additionally, researchers are interested in circRNA because of its potential for early tuberculosis diagnosis and its role as a biomarker. This article systematically analyzes existing literature to provide new insights into early tuberculosis diagnosis and personalized treatment. We also emphasize the need for future research to enhance the application of circRNA in tuberculosis prevention and control.

Circular RNAs perspective: exploring the direction of immunotherapy for colorectal cancer

Circular RNAs (circRNAs) are multifaceted molecules that play a pivotal role in regulating gene expression at both transcriptional and post-transcriptional levels. Their expression is highly tissue-specific and developmentally regulated, making them critical players in various physiological processes and diseases, particularly cancer. In colorectal cancer, circRNAs exhibit significantly dysregulated expression patterns and profoundly influence disease progression through diverse molecular mechanisms. Unraveling the complex roles of circRNAs in modulating colorectal cancer immunotherapy outcomes highlights their potential as both promising biomarkers and therapeutic targets. Moving forward, advancements in circRNA-based therapeutic strategies and delivery systems are poised to transform precision medicine, enabling early colorectal cancer diagnosis and improving patient prognosis.

CircDNA2-Educated YTHDF2 Phase Separation Promotes PM2.5-Induced Malignant Transformation Through the Blunting of GADD45A Expression

Substantial epidemiological evidence suggests a significant correlation between particulate matter 2.5 (PM2.5) and lung cancer. However, the mechanism underlying this association needs to be further elucidated. Circular RNAs (circRNAs) have emerged as an important topic in the field of epigenetics and are involved in various cancers. This study aimed to explore the molecular basis of PM2.5-induced lung cancer from an epigenetic perspective and identify potential biomarkers. Initially, the construction of a chronic PM2.5 exposure model confirmed that PM2.5 exposure promoted the malignant transformation of human bronchial epithelial (HBE) cells. Mechanistically, abnormally upregulated circDNA2 inhibited the tumor suppressor gene growth arrest and DNA damage 45 alpha (GADD45A) mRNA in an N6-methyladenosine (m6A)-dependent manner, mediated by YTH N6-Methyladenosine RNA Binding Protein F2 (YTHDF2) after PM2.5 exposure. Further analyses revealed that circDNA2 can specifically bind to the YTHDF2 LC domain to promote YTHDF2 protein liquid-liquid phase separation (LLPS), providing sufficient evidence linking LLPS and particulate pollutant-induced tumorigenesis. In conclusion, this study provides new insights into the role of circDNA2 in PM2.5-induced lung cancer and confirms its clinical value as a potential prognostic biomarker for lung cancer.

Circular RNAs modulate cancer drug resistance: advances and challenges

Acquired drug resistance is a main factor contributing to cancer therapy failure and high cancer mortality, highlighting the necessity to develop novel intervention targets. Circular RNAs (circRNAs), an abundant class of RNA molecules with a closed loop structure, possess characteristics including high stability, which provide unique advantages in clinical application. Growing evidence indicates that aberrantly expressed circRNAs are associated with resistance against various cancer treatments, including targeted therapy, chemotherapy, radiotherapy, and immunotherapy. Therefore, targeting these aberrant circRNAs may offer a strategy to improve the efficiency of cancer therapy. Herein, we present a summary of the most recently studied circRNAs and their regulatory roles on cancer drug resistance. With the advances in artificial intelligence (AI)-based bioinformatics algorithms, circRNAs could emerge as promising biomarkers and intervention targets in cancer therapy.

CircITGA7 overexpression suppresses HCC progression via miR-330/BCL11B axis regulation

As a kind of prevalent malignancy globally, hepatocellular carcinoma (HCC) is characterized by significant morbidity and mortality due to the difficulties in early diagnosis and limited treatment options. Circular RNAs (circRNAs) are a type of circular single-stranded RNA molecule formed by the back-splicing of the 5' end and the 3' end of linear RNA, possessing multiple biological functions. In recent years, numerous reports have demonstrated that circRNAs are potential biomarkers and therapeutic targets for HCC. In this study, we found that circITGA7 is significantly downregulated in HCC tissue compared to adjacent non-tumor tissue. Functional experiments such as CCK8, EdU, colony formation and wound healing assays proved that overexpression of circITGA7 can effectively inhibit the proliferation, migration and invasion of HCC cells. Further research found that circITGA7 can inhibit miR-330 to release BCL11B expression, thereby promoting P53 expression, blocking the cell cycle and promoting apoptosis in HCC cells. In addition, circITGA7 can impede the proliferation of HCC cells in vivo. Therefore, circITGA7 is a potential biomarker for the diagnosis of HCC development and a potential target for the treatment of HCC.

Circular RNA circDCUN1D4 suppresses hepatocellular carcinoma development via targeting the miR-590-5p/ TIMP3 axis

Hepatocellular carcinoma (HCC) is a major global health concern, necessitating innovative therapeutic strategies. In this study, we investigated the functional role of circular RNA circDCUN1D4 in HCC progression and its potential therapeutic implications. It was found that HCC patients exhibiting higher levels of circDCUN1D4 demonstrated a more favorable survival rate. Furthermore, we revealed that circDCUN1D4 suppressed HCC cell proliferation, migration, and invasion. Mechanistically, circDCUN1D4 was identified as a sponge for miR-590-5p, leading to the downregulation of its downstream target, Tissue Inhibitor of Metalloproteinase 3 (TIMP3). Importantly, circDCUN1D4 administration through In vivo jet-PEI exhibited a robust inhibitory effect on tumor progression without causing notable toxicity in mice. Overall, our findings highlight circDCUN1D4 as a promising therapeutic candidate for HCC, unraveling its intricate regulatory role through the miR-590-5p/TIMP3 axis. This study contributes valuable insights into the potential clinical applications of circRNA-based therapies for HCC.

o8G-modified circPLCE1 inhibits lung cancer progression via chaperone-mediated autophagy

BACKGROUND

Lung cancer poses a serious threat to human health, but its molecular mechanisms remain unclear. Circular RNAs (circRNAs) are closely associated with tumour progression, and the important role of 8-oxoguanine (o8G) modification in regulating the fate of RNA has been gradually revealed. However, o8G modification of circRNAs has not been reported. We identified circPLCE1, which is significantly downregulated in lung cancer, and further investigated the o8G modification of circPLCE1 and the related mechanism in lung cancer progression.

METHODS

We identified differentially expressed circRNAs by RNA high-throughput sequencing and then conducted methylated RNA immunoprecipitation (MeRIP), immunofluorescence (IF) analysis, crosslinking immunoprecipitation (CLIP) and actinomycin D (ActD) assays to explore circPLCE1 o8G modification. The biological functions of circPLCE1 in vivo and in vitro were clarified via establishing a circPLCE1 silencing/overexpression system. Tagged RNA affinity purification (TRAP), RNA Immunoprecipitation (RIP) and coimmunoprecipitation (Co-IP) assays, and pSIN-PAmCherry-KFERQ-NE reporter gene were used to elucidate the molecular mechanism by which circPLCE1 inhibits lung cancer progression.

RESULTS

This study revealed that reactive oxygen species (ROS) can induce circPLCE1 o8G modification and that AUF1 can mediate a decrease in circPLCE1 stability. We found that circPLCE1 significantly inhibited lung cancer progression in vitro and in vivo and that its expression was associated with tumour stage and prognosis. The molecular mechanism was elucidated: circPLCE1 targets the HSC70 protein, increases its ubiquitination level, regulates ATG5-dependent macroautophagy via the chaperone-mediated autophagy (CMA) pathway, and ultimately inhibits lung cancer progression.

CONCLUSION

o8G-modified circPLCE1 inhibits lung cancer progression through CMA to inhibit macroautophagy and alter cell fate. This study provides not only a new theoretical basis for elucidating the molecular mechanism of lung cancer progression but also potential targets for lung cancer treatment.

Potential role of lactylation in intrinsic immune pathways in lung cancer

Lung cancer, one of the most lethal malignancies, has seen its therapeutic strategies become a focal point of significant scientific attention. Intrinsic immune signaling pathways play crucial roles in anti-tumor immunity but face clinical application challenges despite promising preclinical outcomes. Lactylation, an emerging research focus, may influences lung cancer progression by modulating the functions of histones and non-histone proteins. Recent findings have suggested that lactylation regulates key intrinsic immune molecules, including cGAS-STING, TLR, and RIG-I, thereby impacting interferon expression. However, the precise mechanisms by which lactylation governs intrinsic immune signaling in lung cancer remain unclear. This review presents a comprehensive and systematic analysis of the relationship between lactylation and intrinsic immune signaling pathways in lung cancer and emphasizes the innovative perspective of linking lactylation-mediated epigenetic modifications with immune regulation. By thoroughly examining current research findings, this review uncovers potential regulatory mechanisms and highlights the therapeutic implications of targeting lactylation in lung cancer. Future investigations into the intricate interactions between lactylation and intrinsic immunity are anticipated to unveil novel therapeutic targets and strategies, potentially improving patient survival outcomes.

IMPlications of IMP2 in RNA Biology and Disease

Insulin-like growth factor 2 mRNA-binding protein 2 (IMP2) is an RNA-binding protein that positively regulates m6A-modified RNAs involved in critical cellular processes such as metabolism, oncogenesis, and immune function. Here, we elucidate facets of IMP2 biology, including several mechanisms of action on RNA, factors that regulate IMP2 expression, its relevant biological target RNAs, its role in normal development and disease, and its potential as a therapeutic target. IMP2 is a multi-level regulator of metabolism, influencing pathways linked to diabetes, obesity, and adipose function. Through genomic amplification and transcriptional overexpression in cancer cells, IMP2 can drive the initiation and progression of multiple cancer types, and high expression is associated with decreased overall survival of patients with cancer. IMP2 influences normal immune function, inflammation, macrophage polarization, and tumor immune evasion. IMP2 has emerged as a promising therapeutic target, particularly for cancers and metabolic diseases.

MAVS: The next STING in cancers and other diseases

The mitochondrial antiviral signaling protein (MAVS) is a pivotal adaptor in the antiviral innate immune signaling pathway and plays a crucial role in the activation of antiviral defences. This comprehensive review delves into the multifaceted functions of MAVS, spanning from its integral role in the RIG-I-like receptor (RLR) pathway to its emerging roles in tumor biology and autoimmune diseases. We discuss the structural and functional aspects of MAVS, its activation mechanisms, and the intricate regulatory networks that govern its activity. The potential of MAVS as a therapeutic target has been explored, highlighting its promise in personalized cancer therapy and developing combination treatment strategies. Additionally, we compare it with the STING signaling pathway and discuss the synergistic potential of targeting both pathways in immunotherapy. Our review underscores the importance of MAVS in maintaining immune homeostasis and its implications for a broad spectrum of diseases, offering new avenues for therapeutic intervention.

circFOXK2 Stabilizes STMN1 mRNA via PABPC1 to Promote the Progression of NSCLC

BACKGROUND

Lung cancer has a notably high incidence and mortality rate, and understanding its occurrence and development is crucial for effective treatment. Circular RNA is closely associated with tumor progression, playing a role in tumorigenesis and development by regulating gene expression and influencing cell proliferation and apoptosis. This study aims to explore the circFOXK2 role in NSCLC occurrence and development and to elucidate its underlying mechanisms.

METHODS

qRT-PCR and Western Blot analyzed the expressions of circFOXK2, STMN1, and PABPCA in NSCLC cell lines, as well as their relationships. The roles of circFOXK2 and STMN1 in the proliferation, invasion, and migration of NSCLC cells were assessed through CCK8, EDU, and Transwell experiments. RNA pulldown assays with mass spectrometry elucidated the RNA-binding proteins of circFOXK2. Subcutaneous tumorigenesis and tail vein lung metastasis experiments analyzed the impact of circFOXK2 on tumor growth and metastasis in vivo.

RESULTS

In this study, we identified circFOXK2, which is significantly overexpressed in NSCLC, through bioinformatics screening. Elevated levels of circFOXK2 enhance the growth and metastasis of NSCLC cells. Furthermore, through experiments such as co-IP and mass spectrometry, we found that circFOXK2 interacts with PABPC1 to form a complex, which correlates positively with the progression and metastasis of tumors. Simultaneously, the circFOXK2/PABPC1 complex increases the stability of STMN1 mRNA, thereby promoting the transcription and translation of STMN1. Our experimental results indicate that the oncogenic effect of circFOXK2 requires the assistance of STMN1.

CONCLUSIONS

In summary, we have demonstrated the significant role of circFOXK2/PABPC1 in regulating STMN1 expression in NSCLC.

Hsa_circ_0087784 enhances non-small cell lung cancer progression via the miR-576-5p/CDCA4 axis

BACKGROUND

Circular RNAs (circRNAs) belong to a family of covalently closed single-stranded RNAs that have been implicated in cancer progression. Previous studies have reported that hsa_circ_0087784 was abnormally expressed in breast cancer. However, the role of hsa_circ_0087784 in non-small cell lung cancer (NSCLC) is unknown.

METHODS

Here, we used RT-qPCR and FISH to examine hsa_circ_0087784 expression in NSCLC cells and tissue samples. The dual-luciferase reporter assay was used to identify downstream targets of hsa_circ_0087784. Transwell migration, 5-ethynyl-2´-deoxyuridine, and CCK-8 assays were used to examine migration and proliferation. Tumorigenesis and metastasis assays were used to determine the role of hsa_circ_0087784 in NSCLC progression in a mouse tumor xenograft model in vivo.

RESULTS

We found that hsa_circ_0087784 was expressed at significantly high levels in NSCLC tissue samples and cell lines. Downregulation of hsa_circ_0087784 suppressed NSCLC cellular proliferation, as well as migration. Our dual-luciferase reporter assay revealed that miR-576-5p and CDCA4 were downstream targets of hsa_circ_0087784. CDCA4 overexpression or miR-576-5p suppression reversed the effects of hsa_circ_0087784 silencing on NSCLC cell migration, and EMT-related protein expression levels.

CONCLUSION

Our findings suggested that downregulation of hsa_circ_0087784 inhibited NSCLC metastasis and progression through the regulation of CDCA4 expression and miR-576-5p sponging.

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.

EIF4E-mediated biogenesis of circPHF14 promotes the growth and metastasis of pancreatic ductal adenocarcinoma via Wnt/β-catenin pathway

BACKGROUND

CircRNAs are critically involved in the development and progression of various cancers. However, their functions and mechanisms in pancreatic ductal adenocarcinoma (PDAC) remain largely unknown.

METHODS

CircPHF14 (hsa_circ_0079440) was identified through the analysis of RNA sequencing data from PDAC and normal adjacent tissues. The biological functions of circPHF14 were then evaluated using CCK8, EdU, transwell, colony formation, wound healing assays, as well as pancreatic orthotopic xenograft and liver metastasis models. The interaction mechanisms between circPHF14 and PABPC1, which enhance the stability of WNT7A mRNA, were investigated through RNA pull-down, mass spectrometry, RNA Immunoprecipitation (RIP), and actinomycin D assays. The role of EIF4E in promoting circPHF14 biogenesis was examined using RIP, and western blotting.

RESULTS

In this study, we observed a significant upregulation of circPHF14 in both clinical PDAC samples and cell lines. Functionally, circPHF14 enhanced PDAC proliferation and metastasis both in vitro and in vivo. Mechanistically, circPHF14 interacted with PABPC1 to stabilize WNT7A mRNA, thereby activating the Wnt/β-catenin pathway, which subsequently upregulated SNAI2 and initiated Epithelial-Mesenchymal Transition (EMT) in PDAC. Additionally, EIF4E was found to bind PHF14 pre-mRNA, facilitating circPHF14 biogenesis. Finally, we developed a lipid nanoparticle (LNP) formulation encapsulating sh-circPHF14 plasmids and confirmed its anti-tumor efficacy in a patient-derived xenograft (PDX) model.

CONCLUSION

EIF4E-mediated biogenesis of circPHF14 stabilizes WNT7A mRNA via interaction with PABPC1, which subsequently activates the Wnt/β-catenin pathway, promoting the growth and metastasis of PDAC. These findings indicate that circPHF14 holds promise as a biomarker and therapeutic target for PDAC.

Identification of IGF2BPs-related mRNA signature for predicting the overall survival of lung adenocarcinoma

Insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs) are m⁶A readers that stabilize target mRNAs by recognizing the GG(m⁶A)C sequence. While previous studies have explored the biological mechanisms of IGF2BPs in lung cancer, their prognostic value remains unclear. This study investigated the expression, molecular mechanisms, and prognostic significance of IGF2BPs in lung adenocarcinoma (LUAD) using TCGA and GEO datasets. IGF2BP1/2/3 were found to be highly expressed in LUAD, with high mRNA stability scores (RS) associated with shorter overall survival (OS) and linked to hypoxia, EMT, IL2-STAT5 signaling, immune suppression, and decreased gefitinib sensitivity. In cell-based experiments, siRNA knockdown of IGF2BPs in LUAD cell lines reduced TGF-β signaling pathway-related genes and inhibited cell proliferation. Our findings suggest that the IGF2BPs gene signature is a prognostic biomarker in LUAD, contributing to tumor progression, immune escape, and poor prognosis by activating specific pathways.

Innovating non-small cell lung cancer treatment with novel TM-GL/NPs nanoparticles for Glycitin delivery

Sojae semen praeparatum is a traditional Chinese medicine, and its active component, Glycitin, has shown potential in the treatment of non-small cell lung cancer (NSCLC). The purpose of this investigation is to examine the mechanism of action of the effective components of sojae semen praeparatum in the treatment of NSCLC, with a special emphasis on Glycitin, and to explore the integration of nanotechnology in delivering pharmaceutical agents. Key effective components were selected through network pharmacology analysis and functional analysis, and protein-protein interaction analysis and functional enrichment were performed using transcriptomics and metabolomics data to identify the key NSCLC-related target genes and regulatory mechanisms of action of the active components of sojae semen praeparatum. Glycitin-loaded NPs encapsulated in tumor-associated fibroblast membranes were developed to verify their characterization and safety, and their therapeutic effects in inhibiting the malignant phenotype of NSCLC cells through targeting the DNA topoisomerase II alpha (TOP2A) protein were validated. The results indicate that Glycitin exhibits significant anti-tumor activity by affecting the function of the TOP2A protein, thereby inhibiting tumor proliferation and metastasis. This research presents proof of the crucial function of Glycitin in managing NSCLC using sojae semen praeparatum, and sheds light on the possibilities of nanotechnology in drug delivery mechanisms, offering a novel avenue for NSCLC therapy research.

CircPRMT5, a Potential Salivary Biomarker, Facilitates the Progression of Head and Neck Squamous Cell Carcinoma via the IGF2BP3-SERPINE1 Pathway

Purpose

Circular RNAs (circRNAs) are associated with the progression of tumors and hold promise as potential biomarkers for liquid biopsy. Among these, the role of circPRMT5 in head and neck squamous cell carcinoma (HNSCC) remains to be elucidated. This study aims to examine the role and underlying mechanisms of circPRMT5 in the progression of HNSCC and to assess its potential diagnostic value in saliva exosomes.

Methods

The expression of circPRMT5 and its clinical significance in HNSCC were investigated. Both in vitro and in vivo studies were performed to elucidate the biological role of circPRMT5 in HNSCC. RNA sequencing was utilized to identify downstream mechanisms. To evaluate and validate these mechanisms, Western blotting, RNA-FISH, immunofluorescence, immunohistochemistry, RIP, and rescue experiments were employed. Finally, salivary exosomes were isolated, and the expression levels of circPRMT5 were assessed using qRT-PCR.

Results

The upregulation of circPRMT5 in HNSCC tissues was identified to be correlated with cervical lymph node metastasis and advanced clinical T stage. Both in vitro and in vivo experiments manifested that circPRMT5 promoted the proliferation and metastasis of HNSCC. Mechanistically, circPRMT5 was demonstrated to directly bind to and stabilize the insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), which, subsequently, binds to and stabilizes the serpin family E member 1 (SERPINE1) mRNA, thereby enhancing SERPINE1 expression. Furthermore, rescue experiments indicated that the proliferative, invasive, and migratory effects of circPRMT5 in HNSCC were dependent on the involvement of IGF2BP3 and SERPINE1. Notably, circPRMT5 levels were significantly elevated in the saliva exosomes of HNSCC patients, exhibiting substantial diagnostic value.

Conclusion

CircPRMT5 exhibits significant diagnostic utility through salivary exosomes and plays a crucial role in promoting the progression of HNSCC via the IGF2BP3-SERPINE1 pathway. These findings highlight the potential of circPRMT5 as a noninvasive diagnostic biomarker and a therapeutic target for patients with HNSCC.

Circular RNAs in cancer

Circular RNA (circRNA), a subtype of noncoding RNA, has emerged as a significant focus in RNA research due to its distinctive covalently closed loop structure. CircRNAs play pivotal roles in diverse physiological and pathological processes, functioning through mechanisms such as miRNAs or proteins sponging, regulation of splicing and gene expression, and serving as translation templates, particularly in the context of various cancers. The hallmarks of cancer comprise functional capabilities acquired during carcinogenesis and tumor progression, providing a conceptual framework that elucidates the nature of the malignant transformation. Although numerous studies have elucidated the role of circRNAs in the hallmarks of cancers, their functions in the development of chemoradiotherapy resistance remain unexplored and the clinical applications of circRNA-based translational therapeutics are still in their infancy. This review provides a comprehensive overview of circRNAs, covering their biogenesis, unique characteristics, functions, and turnover mechanisms. We also summarize the involvement of circRNAs in cancer hallmarks and their clinical relevance as biomarkers and therapeutic targets, especially in thyroid cancer (TC). Considering the potential of circRNAs as biomarkers and the fascination of circRNA-based therapeutics, the "Ying-Yang" dynamic regulations of circRNAs in TC warrant vastly dedicated investigations.

CircRNF13 enhances IGF2BP1 phase separation-mediated ITGB1 mRNA stabilization in an m6A-dependent manner to promote oral cancer cisplatin chemoresistance

Oral cancer ranks among the most common malignancies within the head and neck region; however, its etiology remains inadequately understood despite substantial research advances in recent years. Many studies highlight the regulatory role of circular RNAs (circRNAs) in human cancers, suggesting their potential as cancer biomarkers. However, their specific mechanisms in oral cancer are not well understood. This study analyzed circRNAs expression in oral cancer, identifying circRNF13 (circbaseID: has_circ_0006801) as having elevated expression in oral cancer cells and tissues. Our study demonstrated that circRNF13 is correlated with increased tumor grade and stage in oral cancer. Results from both in vitro and in vivo experiments indicated that circRNF13 enhances cancer cell proliferation and tumor growth, while concurrently diminishing tumor sensitivity to cisplatin. Mechanistically, circRNF13 interacts with the m6A "reader" protein IGF2BP1, inhibiting its ubiquitin-mediated degradation and promoting its phase separation formation. Subsequently, circRNF13 augments the stability of ITGB1 mRNA via IGF2BP1 in a manner dependent on m6A modification. The m6A modification of ITGB1 mRNA is modulated by the phase separation of IGF2BP1, thereby promoting the malignant progression of oral cancer cells. This evidence positions circRNF13 as a crucial regulatory molecule in the pathogenesis of oral cancer and suggests its potential as a therapeutic target. This discovery enriches our understanding of the mechanistic role of circRNAs.

Mechanisms and therapeutic implications of gene expression regulation by circRNA-protein interactions in cancer

Circular RNAs (circRNAs) have garnered substantial attention due to their distinctive circular structure and gene regulatory functions, establishing them as a significant class of functional non-coding RNAs in eukaryotes. Studies have demonstrated that circRNAs can interact with RNA-binding proteins (RBPs), which play crucial roles in tumorigenesis, metastasis, and drug response in cancer by influencing gene expression and altering the processes of tumor initiation and progression. This review aims to summarize the recent advances in research on circRNA-protein interactions (CPIs) and discuss the functions and mode of action of CPIs at various stages of gene expression, including transcription, splicing, translation, and post-translational modifications in the context of cancer. Additionally, we explore the role of CPIs in tumor drug resistance to gain a deeper understanding of their potential applications in the development of new anti-cancer therapeutic approaches.

EIF4A3-Mediated circ_0008126 Inhibits the Progression and Metastasis of Gastric Cancer by Modulating the APC/β-Catenin Pathway

BACKGROUND

Mounting evidence exhibits circRNAs as critical regulators in the progression of many tumors. The regulatory function and potential mechanism by which circ_0008126 in gastric cancer (GC) is unknown.

METHODS

To validate and analyze the expression levels and clinical values of circ_0008126 in GC patients, the biological phenotypes of circ_0008126 in GC were investigated in vitro and in vivo. The roles and effects of circ_0008126 on miR-502-5p, EIF4A3, and APC in GC cells were explored using rescue experiment, RNA stability assay, RNA pull-down, dual-luciferase reporter, RNA immunoprecipitation (RIP), RNA FISH, immunofluorescence (IF), and TOP/Flash and FOP/Flash assays.

RESULTS

Circ_0008126 expression levels were prominently down-regulated in GC tissues and cells. Importantly, low expression of circ_0008126 was relevant to the more lymphatic metastasis, advanced TNM stage, and poor survival period in patients with GC. Functionally, circ_0008126 inhibited GC cell proliferative activity, metastatic ability, and epithelial-mesenchymal transition (EMT) in vitro and vivo. Mechanistically, we verified that EIF4A3 can mediate the formation of circ_0008126, and circ_0008126 could competitively bind miR-502-5p and alleviate its role and effect on APC, thus inactivating the β-catenin pathway in GC. Additionally, circ_0008126 was determined to increase the stability of APC mRNA by interacting with cytoplasmic EIF4A3 protein and then enhancing the APC expression.

CONCLUSIONS

These data demonstrate that EIF4A3-mediated circ_0008126 could regulate the APC expression and inactivate the β-catenin pathway partly by binding to miR-502-5p and EIF4A3, thus inhibiting the tumorigenesis and development of GC.

circ-ZEB1 Enhances NSCLC Metastasis and Proliferation by Modulating the miR-491-5p/EIF5A Axis

Background: Circular RNAs (circRNAs), covalently closed single-stranded RNAs, have been implicated in cancer progression. A previous investigation revealed that circ-ZEB1 is expressed abnormally in liver cancer. However, the roles of circ-ZEB1 in non-small cell lung cancer (NSCLC) are unknown. Methods: In this study, we used fluorescence in situ hybridization (FISH) and RT-qPCR to study circ-ZEB1 expression in NSCLC cells and tissues. A luciferase reporter assay was performed to validate downstream targets of circ-ZEB1. Transwell migration, 5-ethynyl-20-deoxyuridine (EdU), and cell counting kit-8 (CCK8) assays were performed to assess proliferation and migration. In vivo metastasis and tumorigenesis assays were also performed to investigate circ-ZEB1 functions during NSCLC. Results: Our results showed that circ-ZEB1 expression was increased in NSCLC tissues and cells. circ-ZEB1 downregulation suppressed NSCLC cell proliferation as well as migration in vitro and in vivo. Luciferase data confirmed EIF5A and miR-491-5p as downstream targets of circ-ZEB1. EIF5A overexpression and miR-491-5p suppression reversed NSCLC cell migration post circ-ZEB1 silencing. Conclusion: Our collective findings advised that circ-ZEB1 takes part in the malignant progression through regulating the miR-491-5p/EIF5A axis, highlighting its potential as an effective NSCLC therapeutic target.

Expanding the Potential of Circular RNA (CircRNA) Vaccines: A Promising Therapeutic Approach

In recent years, circular RNAs (circRNAs) have garnered significant attention due to their unique structure and function, positioning them as promising candidates for next-generation vaccines. The circRNA vaccine, as an RNA vaccine, offers significant advantages in preventing infectious diseases by serving as a vector for protein expression through non-canonical translation. Notably, circRNA vaccines have demonstrated enduring antigenic expression and generate a larger percentage of neutralizing antibodies compared to mRNA vaccines administered at the same dosage. Furthermore, circRNA vaccines can elicit robust cellular and humoral immunity, indicating their potential for tumor vaccine development. However, certain challenges must be addressed to facilitate the widespread use of circRNA vaccines in both infectious disease prevention and tumor treatment. These challenges include the low efficiency of linear RNA circularization, the suboptimal targeting of delivery systems, and the assessment of potential side effects. This work aims to describe the characteristics and functions of circRNAs, elucidate the mechanism behind circRNA vaccines, and discuss their applications in the prevention of infectious diseases and the treatment of tumors, along with their potential future applications.

Emerging roles of circular RNAs on the regulation of production traits in chicken

Chickens are vital agricultural animals that supply a significant portion of the protein consumed by humans. In society today, enhancing the productive performance of chickens in a safe and efficient manner has become a central focus of research. This performance is determined by various production traits that are primarily influenced by multiple factors, including epigenetics-a critical aspect of gene regulation. Circular RNAs (circRNAs), a unique class of non-coding RNAs, have emerged as key epigenetic regulators. Recent studies have demonstrated that circRNAs are extensively engaged in numerous production traits, which include skeletal muscle formation, fat deposition, ovarian follicle development, liver function, bone development, immunity, and resistance to environmental stress. These processes play crucial roles in determining the overall productivity of chickens. Given the significance of circRNAs in these various traits, this article provides a comprehensive review of the functional circRNAs associated with different traits in chickens, serving as a valuable theoretical reference for future research. Further investigation into the role of circRNAs may reveal novel insights into the molecular mechanisms underlying key economic traits in chickens and pave the way for innovative strategies in molecular breeding aimed at enhancing chicken productive performance.

Circular RNA SPECC1 promoted tumorigenesis and osimertinib resistance in lung adenocarcinoma via a circular RNA-microRNA network

Background

Tyrosine kinase inhibitors (TKIs) are the first-line therapy for patients with non-small cell lung cancer (NSCLC) with sensitized mutations in the epidermal growth factor receptor (EGFR). However, resistance to TKIs is a major clinical issue that affects the survival and prognosis of the patients, with the mechanisms underlying this resistance remaining elusive. Circular RNAs (circRNAs) are a class of single-stranded, covalently closed RNA molecules, which are generated from pre-messenger RNAs (mRNAs) through back splicing. The aim of this study was to investigate the role of cRNA SPECC1 in promoting resistance to TKIs in NSCLC and to explore its potential involvement in tumorigenesis and metastasis of lung adenocarcinoma (LUAD).

Methods

In this study, we identified differentially expressed genes through RNA sequencing from three tumor samples obtained from patients with poor postoperative TKI treatment outcomes. Validation was performed using quantitative real-time polymerase chain reaction (qRT-PCR) and cell function experiments. We further constructed a competing endogenous RNA (ceRNA) network and performed Gene Ontology (GO) analysis to explore the underlying mechanisms of circRNA.

Results

SPECC1 circular RNA (circSPECC1) was found to be significantly upregulated in tumors as compared to adjacent tissues. Knockdown of circSPECC1 in NSCLC cell lines resulted in decreased proliferation, migration, and invasion. Additionally, apoptosis was increased in cell lines with TKI-sensitive EGFR mutations when treated with osimertinib.

Conclusions

circSPECC1 may promote TKI resistance and contribute to the tumorigenesis and metastasis of NSCLC. This study offers a novel perspective on TKI resistance research at the RNA level.

The therapeutic potential of RNA m(6)A in lung cancer

Lung cancer (LC) is a highly malignant and metastatic form of cancer. The global incidence of and mortality from LC is steadily increasing; the mean 5-year overall survival (OS) rate for LC is less than 20%. This frustrating situation may be attributed to the fact that the pathogenesis of LC remains poorly understood and there is still no cure for mid to advanced LC. Methylation at the N6-position of adenosine (N6mA) of RNA (m(6)A) is widely present in human tissues and organs, and has been found to be necessary for cell development and maintenance of homeostasis. However, numerous basic and clinical studies have demonstrated that RNA m(6)A is deregulated in many human malignancies including LC. This can drive LC malignant characteristics such as proliferation, stemness, invasion, epithelial-mesenchymal transition (EMT), metastasis, and therapeutic resistance. Intriguingly, an increasing number of studies have also shown that eliminating RNA m(6)A dysfunction can exert significant anti-cancer effects on LC such as suppression of cell proliferation and viability, induction of cell death, and reversal of treatment insensitivity. The current review comprehensively discusses the therapeutic potential of RNA m(6)A and its underlying molecular mechanisms in LC, providing useful information for the development of novel LC treatment strategies.

Novel insights into the interaction between IGF2BPs and ncRNAs in cancers

Insulin-like growth factor II mRNA-binding proteins (IGF2BPs), a family of RNA-binding proteins, are pivotal in regulating RNA dynamics, encompassing processes such as localization, metabolism, stability, and translation through the formation of ribonucleoprotein complexes. First identified in 1999 for their affinity to insulin-like growth factor II mRNA, IGF2BPs have been implicated in promoting tumor malignancy behaviors, including proliferation, metastasis, and the maintenance of stemness, which are associated with unfavorable outcomes in various cancers. Additionally, non-coding RNAs (ncRNAs), particularly long non-coding RNAs, circular RNAs, and microRNAs, play critical roles in cancer progression through intricate protein-RNA interactions. Recent studies, predominantly from 2018 onward, indicate that IGF2BPs can recognize and modulate ncRNAs via N6-methyladenosine (m6A) modifications, enriching the regulatory landscape of RNA-protein interactions in the context of cancer. This review explores the latest insights into the interplay between IGF2BPs and ncRNAs, emphasizing their potential influence on cancer biology.

Knockdown of IGF2BP2 overcomes cisplatin-resistance in lung cancer through downregulating Spon2 gene

BACKGROUND

Cisplatin (DDP) resistance has long posed a challenge in the clinical treatment of lung cancer (LC). Insulin-like growth factor 2 binding protein 2 (IGF2BP2) has been identified as an oncogenic factor in LC, whereas its specific role in DDP resistance in LC remains unclear.

RESULTS

In this study, we investigated the role of IGF2BP2 on DDP resistance in DDP-resistant A549 cells (A549/DDP) in vitro and in a DDP-resistant lung tumor-bearing mouse model in vivo. Additionally, methylated RNA immunoprecipitation sequencing (MeRIP-seq) was conducted to identify the potential mRNAs regulated by IGF2BP2, an N6-methyladenosine (m6A) regulator, in the tumor tissues of mice. Compared to normal tissues, IGF2BP2 levels were increased in LC tissues and in relapsed/resistant LC tissues. Most importantly, IGF2BP2 levels were significantly higher in relapsed/resistant LC tissues than in LC tissues. Significantly, knockdown of IGF2BP2 or DDP treatment inhibited A549 cell viability, migration, and cell cycle progression. Consistently, DDP treatment suppressed the viability and migration and triggered cell cycle arrest in A549/DDP cells in vitro, as well as reduced tumor volume and weight of A549/DDP tumor-bearing mice; meanwhile, the combination of DDP and IGF2BP2 siRNA further significantly inhibited A549/DDP cell growth in vitro and in vivo compared to DDP treatment alone. Furthermore, MeRIP-seq data showed that IGF2BP2 downregulation remarkably elevated m6A levels of spondin 2 (Spon2) and reduced mRNA levels of Spon2 in tumor tissues from A549 tumor-bearing mice. Meanwhile, the combination of DDP and IGF2BP2 siRNA notably reduced Spon2 levels, as well as inhibited the viability and induced apoptosis in A549/DDP cells; however, these effects were reversed by Spon2 overexpression.

CONCLUSION

Collectively, downregulation of IGF2BP2 could overcome DDP resistance in LC through declining the Spon2 gene expression in an m6A-dependent manner. These results may provide a new strategy for overcoming DDP resistance in LC.

Molecular Biology of Cancer-Interplay of Malignant Cells with Emerging Therapies

Cancer is currently one of the leading causes of death worldwide, and according to data from the World Health Organization reported in 2020, it ranks as the second leading cause of death globally, accounting for 10 million fatalities [...].

Hsa_circ_0002346 inhibits proliferation, invasion, and migration of breast cancer cells and promotes apoptosis: A novel potential biomarker for breast cancer

BackgroundCircular RNA hsa_circ_0002346 has been implicated in the progression of various tumors, yet the functional role in breast cancer remains poorly understood. This study aimed to investigate the significance of hsa_circ_0002346 in breast cancer (BC).MethodsQuantitative reverse transcriptase polymerase chain reaction assays were performed to detect hsa_circ_0002346 expression in BC cell lins and 27 patients with BC. Then, siRNAs were used to knock down hsa_circ_0002346. And detecting function of downregulated hsa_circ_0002346 by proliferation colony formation, apoptosis assays, wound-healing assays and Transwell assays. Finally, we assess the levels of the EMT-associated proteins.ResultsOur findings suggest that hsa_circ_0002346 levels were significantly downregulated in breast cancer and may play a crucial role in regulating key cellular processes associated with cancer progression. The expression level of hsa_circ_0002346 was correlated with lymph node metastasis. The knockdown of hsa_circ_0002346 resulted in increased tumor cell proliferation, invasion, migration and decreased apoptosis. Additionally, alterations in the expression of EMT-associated proteins further support the hypothesis that hsa_circ_0002346 is implicated in the metastatic processes of breast cancer.Conclusionhsa_circ_0002346 emerges as a promising biomarker for breast cancer and a potential therapeutic target for future treatment strategies.

Circular RNA circRANGAP1/miR-512-5p/SOD2 Axis Regulates Cell Proliferation and Migration in Non-small Cell Lung Cancer (NSCLC)

Non-small cell lung cancer (NSCLC) is the most prevalent histology type of lung cancer worldwide, accounting for 18% of total cancer-related deaths estimated by GLOBOCAN in 2020. CircRNAs have emerged as potent regulators of NSCLC development. CircRANGAP1 (hsa_circ_0001235/hsa_circ_0063526) is a potential biomarker for NSCLC identified by microarray dataset analysis. Here, we investigated the biological functions of circRANGAP1 in NSCLC development and elucidated the associated competing endogenous RNA (ceRNA) mechanisms. We found that circRANGAP1 expression was upregulated in NSCLC tissues and cells, which was inversely correlated with carcinogenesis and poor clinical outcome of NSCLC patients. CircRANGAP1 knockdown inhibited NSCLC migration by regulating miR-512-5p/SOD2 axis. In conclusion, circRANGAP1 facilitated NSCLC tumorigenesis and development by sponging miR-512-5p to upregulate SOD2 expression. Suppression of circRANGAP1 expression by si-circRANGAP1 treatment could be a strategy to inhibit NSCLC development and metastasis.

WTAP-Mediated m6A Modification of circSMOC1 Accelerates the Tumorigenesis of Non-Small Cell Lung Cancer by Regulating miR-612/CCL28 Axis

Accumulating evidence reveals that deregulated N6-methyladenosine (m6A) RNA methylation and circular RNAs (circRNAs) are required for the tumorigenesis of non-small cell lung cancer (NSCLC). We aimed to uncover the underlying mechanisms by which WTAP-mediated m6A modification of circRNA contributes to NSCLC. The differentially-expressed circRNAs were identified by a circRNA profiling microarray. The association of circSMOC1 with clinicopathological features and prognosis in patients with NSCLC was estimated by fluorescence in situ hybridization. WTAP-mediated m6A modification of circRNA was validated by RNA immunoprecipitation (RIP) and methylated RIP (MeRIP) assays. The role of circSMOC1 in NSCLC cells was validated by in vitro functional experiments and in vivo tumorigenesis models. CircSMOC1-specific binding with miR-612 was verified by RIP, luciferase gene report and RT-qPCR assays. The effect of circSMOC1 and/or miR-612 on CCL28 expression was detected by RT-qPCR and Western blotting analysis. We found that the expression levels of circSMOC1 were elevated in NSCLC tissues and associated with TNM stage and poor survival in patients with NSCLC. Knockdown of circSMOC1 impaired the tumorigenesis of NSCLC in vitro and in vivo, whereas restored expression of circSMOC1 displayed the opposite effect. Furthermore, WTAP was upregulated in NSCLC and mediated m6A modification of circSMOC1 and circSMOC1 abolished WTAP knockdown-caused tumour-suppressive effects. Then, circSMOC1 acted as a sponge of miR-612 to upregulate CCL28 and miR-612 inhibitors abrogated circSMOC1 knockdown-caused anti-proliferation effects and CCL28 downregulation in NSCLC cells. Knockdown of CCL28 inhibited cell proliferation and invasion and counteracted miR-612 inhibitor-caused tumour-promoting effects. Our findings unveil that WTAP-mediated m6A modification of circSMOC1 facilitates the tumorigenesis of NSCLC by regulating the miR-612/CCL28 axis.

The potential of circular RNAs as biomarkers and therapeutic targets for gastric cancer: A comprehensive review

BACKGROUND

Gastric cancer (GC) is a global health concern, contributing significantly to cancer-related mortality rates. Early detection is vital for improving patient outcomes. Recently, circular RNAs (circRNAs) have emerged as crucial players in the development and progression of various cancers, including GC.

AIM

This comprehensive review underscores the promising potential of circRNAs as innovative biomarkers for the early diagnosis of GC, as well as their possible utility as therapeutic targets for this life-threatening disease. Specifically, the review focuses on recent findings, mechanistic insights, and clinical applications of circRNAs in GC.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Dysregulation of circRNAs has been consistently observed in GC tissues, offering potential diagnostic value due to their stability in bodily fluids such as blood and urine. For instance, circPTPN22 and hsa_circ_000200. Furthermore, the expression levels of circRNAs such as circCUL2, hsa_circ_0000705 and circSHKBP1 have shown strong associations with critical clinical features of GC, including diagnosis, prognosis, tumor size, lymph node metastasis, tumor-node-metastasis (TNM) stage, and treatment response. Additionally, circRNAs such as circBGN, circLMO7, and circMAP7D1 have shown interactions with specific microRNAs (miRNAs), proteins, and other molecules that play key roles in development and progression of GC. This further highlighting their potential as therapeutic targets. Despite their potential, several challenges need to be addressed to effectively apply circRNAs as GC biomarkers. These include standardizing detection methods, establishing cutoff values for diagnostic accuracy, and validating findings in larger patient cohorts. Moreover, the functional mechanisms by which circRNAs contribute to GC pathogenesis and therapeutic resistance warrant further investigation. Advances in circRNAs research could provide valuable insights into the early detection and targeted treatment of GC, ultimately improving patient outcomes.

NSUN4-mediated m5C modification of circERI3 promotes lung cancer development by altering mitochondrial energy metabolism

As a highly important methylation modification, the 5-methyladenosine (m5C) modification can profoundly affect RNAs by regulating their transcription, structure and stability. With the continuous development of high-throughput technology, differentially expressed circular RNAs (circRNAs) have been increasingly discovered, and circRNAs play unique roles in tumorigenesis and development. However, the regulatory mechanism of the m5C modification of circRNAs has not yet been revealed. In this study, circERI3, which is highly expressed in lung cancer tissue and significantly correlated with the clinical progression of lung cancer, was initially identified through differential expression profiling of circRNAs. A combined m5C microarray analysis revealed that circERI3 contains the m5C modification and that the NSUN4-mediated m5C modification of circERI3 can increase its nuclear export. The important function of circERI3 in promoting lung cancer progression in vitro and in vivo was clarified. Moreover, we elucidated the novel mechanism by which circERI3 targets DNA binding protein 1 (DDB1), regulates its ubiquitination, enhances its stability, and in turn promotes the transcription of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) through DDB1 to affect mitochondrial function and energy metabolism, which ultimately promotes the development of lung cancer. This study not only revealed the reasons for the abnormal distribution of circERI3 in lung cancer tissues from the perspective of methylation and clarified the important role of circERI3 in lung cancer progression but also described a novel mechanism by which circERI3 promotes lung cancer development through mitochondrial energy metabolism, providing new insights for the study of circRNAs in lung cancer.

Constructing and identifying an eighteen-gene tumor microenvironment prognostic model for non-small cell lung cancer

BACKGROUND

The tumor microenvironment (TME) plays a crucial role in tumorigenesis and tumor progression. This study aimed to identify novel TME-related biomarkers and develop a prognostic model for patients with non-small-cell lung cancer (NSCLC).

METHODS

After downloading and preprocessing data from The Cancer Genome Atlas (TCGA) data portal and Gene Expression Omnibus (GEO) datasets, we classified the molecular subtypes using the "NMF" R package. We performed survival analysis and quantified immune scores between clusters. A Cox proportional hazards model was then constructed, and its formula was produced. We assessed model performance and clinical utility. A prediction nomogram was also constructed and validated. Additionally, we explored the potential regulatory mechanisms of our TME gene signature using Gene Set Enrichment Analysis (GSEA).

RESULTS

From data processing and univariate Cox regression analysis, 57 TME-related prognostic genes were identified, and two significantly distinct clusters were established. Using Cox regression and Lasso regression, an 18-gene TME-related prognostic model was developed. Patients were stratified into high- and low-risk groups based on the risk score, with survival analysis showing that the low-risk group had significantly better outcomes than the high-risk group (P < 0.01). ROC curve analysis demonstrated strong predictive performance, with 1-year, 3-year, and 5-year AUC values ranging from 0.654 to 0.702 across different cohorts. The model accurately predicted survival outcomes across subgroups with varying clinical features, and its predictive accuracy was validated through a nomogram.

CONCLUSIONS

We developed a prognostic model based on TME-related genes in NSCLC. Our 18-gene TME signature can effectively predict the prognosis of NSCLC with high accuracy.

Circ_0001944 Targets the miR-1292-5p/FBLN2 Axis to Facilitate Sorafenib Resistance in Hepatocellular Carcinoma by Impeding Ferroptosis

BACKGROUND

Sorafenib, an orally active potent tyrosine kinase inhibitor (TKI), represented a primary treatment in patients with advanced hepatocellular carcinoma (HCC). Unfortunately, sorafenib resistance was regarded as a huge obstacle for HCC treatment.

METHODS

RNA-sequencing including circRNA Sequencing (circRNA-Seq) for circular RNAs (circRNAs), miRNA Sequencing (miRNA-Seq) for microRNAs (miRNAs), as well as mRNA Sequencing (mRNA-Seq) for mRNAs in sorafenib-resistant HCC cells vs sorafenib-sensitive HCC cells, were performed. Then, interaction correlation analysis between differentially expressed circRNAs and miRNAs and their target genes in Huh7/SOR and SMMC7721/SOR cells was exhibited. The "circRNA-miRNA-mRNA" network was constructed through the Cytoscape software application, Circular RNA Interactome and Targetscan prediction, RNA binding protein immunoprecipitation (RIP), RNA pull-down, and Dual luciferase reporter assay. Furthermore, mRNA-Seq, Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis for the downstream genes involved in the "circRNA-miRNA-mRNA" network was implemented. Iron detection assay, Lipid peroxidation quantification assay, ROS measurement assay, CCK-8 assay, and tumor challenge in vivo were used to determine the mechanisms promoting sorafenib resistance in HCC, where the "circRNA-miRNA-mRNA" network is clearly involved in.

RESULTS 

circ_0001944 and circ_0078607 with upregulation and 2 downregulated expressed circRNAs (circ_0002874 and circ_0069981), as well as 11 upregulated miRNAs including miR-193a-5p, miR-197-3p, miR-27a-5p, miR-551b-5p, miR-335-3p, miR-767-3p, miR-767-5p, miR-92a-1-5p, miR-92a-3p, miR-3940-3p, and miR-664b-3p and 3 downregulated expressed miRNAs (miR-1292-5p, let-7c-5p, and miR-99a-5p) in sorafenib-resistant HCC cells were determined. Among these non-coding RNAs (ncRNAs), circ_0001944 and miR-1292-5p should not be drop out of sight; circ_0001944 has been proved to target miR-1292-5p to inhibit its expression in HCC. Subsequent findings also raise that miR-1292-5p directly targeted the 3'-noncoding region (3'-UTR) of Fibulin 2 (FBLN2) mRNA. Furthermore, circ_0001944 targets the miR-1292-5p/FBLN2 axis to inhibit cell ferroptosis in which the indicated regulators associated with iron overload and lipid peroxidation were "rearranged". Most importantly, circ_0001944 advanced sorafenib resistance in HCC through mitigating ferroptosis, where the miR-1292-5p/FBLN2 axis cannot be left unrecognized.

CONCLUSION 

Circ_0001944 is a putative target for reversing sorafenib resistance in HCC. Our findings are expected to provide new targets and new directions for sorafenib sensitization in the treatment of HCC.

m6A regulator-mediated methylation modifications define the immune infiltration characteristics of the tumor microenvironment in prostate adenocarcinoma

Prostate adenocarcinoma (PRAD) persists as the predominant non-cutaneous malignancy diagnosed in males, which is a primary contributor to cancer-related mortality globally. It is reported that the progression of prostate adenocarcinoma is associated with various factors, including genetics, age, obesity, etc. Contemporary research indicates that epigenetic inheritance is a leading factor in the initiation and progression of cancer. RNA methylation modification is the most prevalent form of RNA modification, with N6-methyladenosine (m6A) representing the most common modification on mRNA and lncRNAs. However, the biological mechanisms underpinning this association in prostate adenocarcinoma and its correlation with patients' prognostic survival outcomes remain elusive. Our study elucidates the roles of the tumor microenvironment (TME) and genetic mutations during the initiation and progression of prostate adenocarcinoma. Additionally, we stratify prostate adenocarcinoma into distinct subtypes based on m6A scoring. This approach enhances our comprehension of the functional role of m6A in the development of prostate adenocarcinoma, offering novel insights into the clinical strategies and understanding the biological significance between prostate adenocarcinoma and m6A modification.