RNA-binding proteins and cancer metastasis

The regulatory roles of RNA-binding proteins in the tumour immune microenvironment of gastrointestinal malignancies

The crosstalk between the tumour immune microenvironment (TIME) and tumour cells promote immune evasion and resistance to immunotherapy in gastrointestinal (GI) tumours. Post-transcriptional regulation of genes is pivotal to GI tumours progression, and RNA-binding proteins (RBPs) serve as key regulators via their RNA-binding domains. RBPs may exhibit either anti-tumour or pro-tumour functions by influencing the TIME through the modulation of mRNAs and non-coding RNAs expression, as well as post-transcriptional modifications, primarily N6-methyladenosine (m6A). Aberrant regulation of RBPs, such as HuR and YBX1, typically enhances tumour immune escape and impacts prognosis of GI tumour patients. Further, while targeting RBPs offers a promising strategy for improving immunotherapy in GI cancers, the mechanisms by which RBPs regulate the TIME in these tumours remain poorly understood, and the therapeutic application is still in its early stages. This review summarizes current advances in exploring the roles of RBPs in regulating genes expression and their effect on the TIME of GI tumours, then providing theoretical insights for RBP-targeted cancer therapies.

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.

The role of RNA binding proteins in cancer biology: A focus on FMRP

RNA-binding proteins (RBPs) act as crucial regulators of gene expression within cells, exerting precise control over processes such as RNA splicing, transport, localization, stability, and translation through their specific binding to RNA molecules. The diversity and complexity of RBPs are particularly significant in cancer biology, as they directly impact a multitude of RNA metabolic events closely associated with tumor initiation and progression. The fragile X mental retardation protein (FMRP), as a member of the RBP family, is central to the neurodevelopmental disorder fragile X syndrome and increasingly recognized in the modulation of cancer biology through its influence on RNA metabolism. The protein's versatility, stemming from its diverse RNA-binding domains, enables it to govern a wide array of transcript processing events. Modifications in FMRP's expression or localization have been associated with the regulation of mRNAs linked to various processes pertinent to cancer, including tumor proliferation, metastasis, epithelial-mesenchymal transition, cellular senescence, chemotherapy/radiotherapy resistance, and immunotherapy evasion. In this review, we emphasize recent findings and analyses that suggest contrasting functions of this protein family in tumorigenesis. Our knowledge of the proteins that are regulated by FMRP is rapidly growing, and this has led to the identification of multiple targets for therapeutic intervention of cancer, some of which have already moved into clinical trials or clinical practice.

The RNA-Binding Proteins MCPIP2 and IGF2BP1 Competitively Modulate Breast Tumor Angiogenesis by Antagonizing VEGFA mRNA Stability and Expression

Tumor angiogenesis is essential for further growth and metastasis of solid tumors. However, the mechanisms underlying angiogenesis-related gene expression have yet to be clarified. Here, we discovered RNA-binding proteins monocyte chemotactic protein-induced protein 2 (MCPIP2) and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) function as a pair of antagonists that modulate breast tumor angiogenesis by competitively regulating mRNA stability of proangiogenic gene transcripts, including vascular endothelial growth factor A (VEGFA), Erb-B2 receptor tyrosine kinase 2 (ERBB2), interleukin-8 (IL8), C-X-C motif chemokine ligand 1 (CXCL1), and ephrin A1 (EFNA1). Mechanistically, MCPIP2 physically interacted with the stem-loop structures in the 3'-untranslated region of proangiogenic transcripts through its RNase domain to destabilize their mRNAs. Ribosomal proteins might be required for MCPIP2-mediated destabilization of proangiogenic mRNAs. On the other hand, IGF2BP1 can stabilize the proangiogenic mRNAs by binding to the common RNA stem-loop structures. Furthermore, we found that MCPIP2 expression in human breast tumors was repressed, whereas IGF2BP1 expression increased. Lower MCPIP2 expression and higher IGF2BP1 expression in human breast tumors were significantly associated with poor survival of breast cancer patients, respectively. Notably, there was a reversed correlation relationship between MCPIP2, IGF2BP1 expression, and proangiogenic gene expression in human breast tumor samples. Collectively, our results elucidate a novel mechanism by which MCPIP2 and IGF2BP1 competitively modulate the expression of proangiogenic transcripts, which provides new insights into antiangiogenic therapy of breast cancer.

Targeting metastasis in paediatric bone sarcomas

Paediatric bone sarcomas (e.g. Ewing sarcoma, osteosarcoma) comprise significant biological and clinical heterogeneity. This extreme heterogeneity affects response to systemic therapy, facilitates inherent and acquired drug resistance and possibly underpins the origins of metastatic disease, a key component implicit in cancer related death. Across all cancers, metastatic models have offered competing accounts on when dissemination occurs, either early or late during tumorigenesis, whether metastases at different foci arise independently and directly from the primary tumour or give rise to each other, i.e. metastases-to-metastases dissemination, and whether cell exchange occurs between synchronously growing lesions. Although it is probable that all the above mechanisms can lead to metastatic disease, clinical observations indicate that distinct modes of metastasis might predominate in different cancers. Around 70% of patients with bone sarcoma experience metastasis during their disease course but the fundamental molecular and cell mechanisms underlying spread are equivocal. Newer therapies such as tyrosine kinase inhibitors have shown promise in reducing metastatic relapse in trials, nonetheless, not all patients respond and 5-year overall survival remains at ~ 50%. Better understanding of potential bone sarcoma biological subgroups, the role of the tumour immune microenvironment, factors that promote metastasis and clinical biomarkers of prognosis and drug response are required to make progress. In this review, we provide a comprehensive overview of the approaches to manage paediatric patients with metastatic Ewing sarcoma and osteosarcoma. We describe the molecular basis of the tumour immune microenvironment, cell plasticity, circulating tumour cells and the development of the pre-metastatic niche, all required for successful distant colonisation. Finally, we discuss ongoing and upcoming patient clinical trials, biomarkers and gene regulatory networks amenable to the development of anti-metastasis medicines.

Anti-metastatic potential of flavonoids for the treatment of cancers: focus on epithelial-mesenchymal transition (EMT) process

The leading factor contributing to patient mortality is the local invasion and metastasis of tumors, which are influenced by the malignant progression of tumor cells. The epithelial-mesenchymal transition (EMT) is key to understanding malignancy development. EMT is a critical regulatory mechanism for differentiating cell populations initially observed during the neural crest and embryonic gastrulation formation. This process is closely associated with tumor metastasis in cancer and is also related to the maintenance of cancer stem cells. Flavonoids, known for their antioxidant properties, have been widely studied for their anticancer potential to protect plants from harmful environmental conditions. They have attracted considerable attention and have been the focus of numerous experimental and epidemiological studies to evaluate their potential in cancer treatment. In vitro and in vivo research has demonstrated that flavonoids can significantly impact cancer-related EMT. They may inhibit the EMT process by reducing the levels of Twist1, N-cadherin, ZEB1, integrins, SNAI1/2, CD44, MMPs, and vimentin while increasing E-cadherin levels and targeting the PI3K/AKT, NF-κB p65, and JAK2/STAT3 signaling pathways. In order to suppress the transcription of the E-cadherin promoter, several Zn-finger transcription factors, such as SNAI2, ZEB1, and ZEB2, and basic helix-loop-helix (bHLH) factors, such as Twist, may directly bind to its E-boxes. Overall, clinical cancer research should integrate the anticancer properties of flavonoids, which address all phases of carcinogenesis, including EMT, to improve the prospects for targeted cancer therapies in patients suffering from aggressive forms of tumors.

Biological function of RNA-binding proteins in myocardial infarction: a potential emerging therapeutic limelight

Myocardial infarction (MI) is currently one of the most fatal cardiovascular diseases worldwide. The screening, treatment, and prognosis of MI are top priorities for cardiovascular centers globally due to its characteristic occult onset, high lethality, and poor prognosis. MI is caused by coronary artery occlusion induced by coronary atherosclerotic plaque blockage or other factors, leading to ischemic necrosis and apoptosis of cardiomyocytes. Although significant advancements have been made in the study of cardiomyocytes at the cellular and molecular levels, RNA-binding proteins (RBPs) have not been extensively explored in the context of MI. RBPs, as key regulators coordinating cell differentiation and tissue homeostasis, exhibit specific functions in gene transcription, RNA modification and processing, and post-transcriptional gene expression. By binding to their target RNA, RBPs coordinate various RNA dynamics, including cellular metabolism, subcellular localization, and translation efficiency, thereby controlling the expression of encoded proteins. Classical RBPs, including HuR, hnRNPs, and RBM family molecules, have been identified as critical regulators in myocardial hypoxia, oxidative stress, pro-inflammatory responses, and fibrotic repair. These RBPs exert their effects by modulating key pathophysiological pathways in MI, thereby influencing specific cardiac outcomes. Additionally, specific RBPs, such as QKI and fused in sarcoma (FUS), are implicated in the apoptotic pathways activated during MI. This apoptotic pathway represents a significant molecular phenotype in MI, offering novel perspectives and insights for mitigating cardiomyocyte apoptosis and attenuating the progression of MI. Therefore, this review systematically summarizes the role of RBPs in the main pathophysiological stages of MI and explores their potential therapeutic prospects.

Advances in the role of baicalin and baicalein in colon cancer: mechanisms and therapeutic potential

Colorectal cancer (CRC) remains a malignancy with high incidence and mortality rates worldwide, necessitating the development of more effective therapeutic strategies due to the limitations of current treatments, including drug resistance and adverse effects. Scutellaria baicalensis, a traditional Chinese medicinal herb, contains baicalin and baicalein as its primary bioactive flavonoids, which exhibit notable pharmacological properties such as antibacterial, anti-inflammatory, antioxidant, and antitumor effects. Recent studies have demonstrated that baicalin and baicalein show promising antitumor activity in CRC treatment through mechanisms such as scavenging reactive oxygen species, immune regulation, and inhibition of tumor cell proliferation, induction of apoptosis, and modulation of the gut microenvironment. This study further investigates the molecular mechanisms underlying the therapeutic effects of baicalin and baicalein in CRC, aiming to provide new research perspectives and potential clinical applications for the integration of flavonoid-based compounds from Scutellaria baicalensis in CRC treatment.

IGF2BP3-regulated circPLEKHH2 promotes autophagy via AKT/mTOR signaling pathway to suppress lung adenocarcinoma progression

Lung adenocarcinoma (LUAD) is the most common malignant tumor in the lung. Circular RNAs (circRNAs) play critical roles in cancer progression. However, the functions and mechanisms of circPLEKHH2 in regulating cancer progression and autophagy in LUAD are largely unknown. Our research team identified circPLEKHH2 (annotated as hsa_circ_0120106) which is significantly down-regulated in LUAD via RNA-seq in 14 pairs of LUAD tissues. The expression level of circPLEKHH2 in patient tissue has potential diagnostic value to distinguish LUAD tissue from normal lung tissue. Functionally, circPLEKHH2 promoted autophagy and inhibited LUAD cell proliferation, invasion, migration, and tumor growth. Mechanistically, we identified that circPLEKHH2 promoted autophagy via the AKT/mTOR signaling pathway, and the mTOR inhibitor rapamycin can reverse the oncogenic effects of circPLEKHH2 silencing. IGF2BP3 can bind to circPLEKHH2 to inhibit its expression. These results revealed that as a tumor suppressor, IGF2BP3-regulated circPLEKHH2 promotes autophagy through the AKT/mTOR signaling pathway to inhibit the occurrence and progression of LUAD. Therefore, circPLEKHH2 could be a potential therapeutic target for LUAD.

Value of Bioinformatics Models for Predicting Translational Control of Angiogenesis

Angiogenesis, the formation of new blood vessels, is a fundamental biological process with implications for both physiological functions and pathological conditions. While the transcriptional regulation of angiogenesis, mediated by factors such as HIF-1α (hypoxia-inducible factor 1-alpha) and VEGF (vascular endothelial growth factor), is well-characterized, the translational regulation of this process remains underexplored. Bioinformatics has emerged as an indispensable tool for advancing our understanding of translational regulation, offering predictive models that leverage large data sets to guide research and optimize experimental approaches. However, a significant gap persists between bioinformatics experts and other researchers, limiting the accessibility and utility of these tools in the broader scientific community. To address this divide, user-friendly bioinformatics platforms are being developed to democratize access to predictive analytics and empower researchers across disciplines. Translational control, compared with transcriptional control, offers a more energy-efficient mechanism that facilitates rapid cellular responses to environmental changes. Furthermore, transcriptional regulators themselves are often subject to translational control, emphasizing the interconnected nature of these regulatory layers. Investigating translational regulation requires advanced, accessible bioinformatics tools to analyze RNA structures, interacting micro-RNAs, long noncoding RNAs, and RBPs (RNA-binding proteins). Predictive platforms such as RNA structure, human internal ribosome entry site Atlas, and RBPSuite enable the study of RNA motifs and RNA-protein interactions, shedding light on these critical regulatory mechanisms. This review highlights the transformative role of bioinformatics using widely accessible user-friendly tools with a Web-browser interface to elucidate translational regulation in angiogenesis. The bioinformatics tools discussed extend beyond angiogenesis, with applications in diverse fields, including clinical care. By integrating predictive models and experimental insights, researchers can streamline hypothesis generation, reduce experimental costs, and find novel translational regulators. By bridging the bioinformatics knowledge gap, this review aims to empower researchers worldwide to adopt bioinformatics tools in their work, fostering innovation and accelerating scientific discovery.

Understanding the Molecular Mechanisms of SORBS2 in TNBC Lung Metastasis

Metastasis is the leading cause of recurrence and mortality in triple-negative breast cancer (TNBC), an aggressive subtype that predominantly spreads to the lungs, brain, bones, and liver, with lung metastasis being particularly prevalent. Despite the clinical significance of TNBC metastasis, the molecular mechanisms that drive lung-specific metastasis remain poorly understood. RNA-binding proteins (RBPs) are crucial regulators of post-transcriptional gene expression and are frequently dysregulated in cancers. This study identifies SORBS2 as a critical RBP implicated in TNBC lung metastasis. Using RNA sequencing (RNA-seq) and LACE-seq, we demonstrate that SORBS2 regulates a specific set of genes through direct binding to coding sequences (CDS), introns, and 3' untranslated regions (UTRs), and its binding targets are linked to various pathways, including a possible association with Wnt/β-catenin signaling, among others. Functional assays confirm that SORBS2 knockdown inhibits proliferation, migration, and invasion in TNBC cells. These findings highlight SORBS2 as a key regulator of TNBC lung metastasis, with a context-dependent role that promotes metastatic behavior in highly metastatic TNBC cells, providing potential avenues for novel therapeutic strategies.

The Functional Diversity of Chromatin-Associated RNA Binding Proteins in Transcriptional and Post-Transcriptional Regulation

RNA-binding proteins (RBPs) are a diverse class of proteins that interact with their target RNA molecules to regulate gene expression at the transcriptional and post-transcriptional levels. RBPs contribute to almost all aspects of RNA processing with sequence-specific, structure-specific, and nonspecific binding modes. Advances in our understanding of the mechanisms of RBP-mediated regulatory networks consisting of DNAs, RNAs, and protein complexes and the association between these networks and human diseases have been made very recently. Here, we discuss the "unconventional" functions of RBPs in transcriptional regulation by focusing on the cutting-edge investigations of chromatin-associated RBPs (ChRBPs). We briefly introduce examples of how ChRBPs influence the genomic features and molecular structures at the level of transcription. In addition, we focus on the post-transcriptional functions of various RBPs that regulate the biogenesis, transportation, stability control, and translation ability of circular RNA molecules (circRNAs). Lastly, we raise several questions about the clinical significance and potential therapeutic utility of disease-relevant RBPs.

Emerging roles of exosomal circRNAs in non-small cell lung cancer

Despite the prevalence of non-small cell lung cancer (NSCLC) is high, the limited early detection and management of these tumors are restricted since there is an absence of reliable and precise diagnostic biomarkers and therapeutic targets. Exosomes transport functional molecules for facilitating intercellular communication, especially in the tumor microenvironment, indicating their potential as cancer biomarkers and therapeutic targets. Circular RNA (circRNA), a type of non-coding RNA possessing a covalently closed loop structure, substantial abundance, and tissue-specific expression patterns, is stably enriched in exosomes. In recent years, significant breakthroughs have been made in research on exosomal circRNA in NSCLC. This review briefly introduces the biogenesis, characterizations, and functions of circRNAs and exosomes, and systematically describes the biological functions and mechanisms of exosomal circRNAs in NSCLC. In addition, this study summarizes their role in the progression of NSCLC and discusses their clinical significance as biomarkers and therapeutic targets for NSCLC.

Engineered nanoparticles for imaging and targeted drug delivery in hepatocellular carcinoma

Liver cancer, notably hepatocellular carcinoma (HCC), poses a significant global health burden due to its high fatality rates. Conventional antitumor medications face challenges, including poor targeting, high toxicity, and drug resistance, leading to suboptimal clinical outcomes. This review focused on nanoparticle use in diagnosing and delivering medication for HCC, aiming to advance the development of nanomedicines for improved treatment outcomes. As an emerging frontier science and technology, nanotechnology has shown great potential, especially in precision medicine and personalized treatment. The success of nanosystems is attributable to their smaller size, biocompatibility, selective tumor accumulation, and lower toxicity. Nanoparticles, as a central part of nanotechnology innovation, have emerged in the field of medical diagnostics and therapeutics to overcome the various limitations of conventional chemotherapy, thus offering promising applications for improved selectivity, earlier and more precise diagnosis of cancers, personalized treatment, and overcoming drug resistance. Nanoparticles play a crucial role in drug delivery and imaging of HCC, with the body acting as a delivery system to target and deliver drugs or diagnostic reagents to specific organs or tissues, helping to accurately diagnose and target therapies while minimizing damage to healthy tissues. They protect drugs from early degradation and increase their biological half-life.

The anti-metastatic effect of elemene in human hepatocellular carcinoma is potentially mediated by inhibiting a novel driver-circBPTF

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide, with metastasis being one of the primary characteristics. Elemene, a natural product derived from Curcuma wenyujin, has been approved for treating advanced and metastasis HCC patients. However, the molecular mechanism of elemene in HCC is still unclear.

PURPOSE

Dysregulation circular RNA (circRNA) plays a critical role in the progression of HCC. This study aimed to evaluate the anti-HCC mechanism of elemene from circRNA point.

METHODS

Transwell and wound-healing assays were employed to evaluate the function of circBPTF and elemene in vitro. Orthotopic xenograft tumor mouse models were used to explore the metastatic impact of circBPTF in vivo and were evaluated by haematoxylin and eosin (H&E) and immunohistochemistry (IHC). To investigate the effects of elemene on circBPTF, RNA pulldown, western blotting, qPCR, transwell and RNA-seq assays were employed.

RESULTS

In this study, we demonstrated circBPTF (hsa_circ_0045431) was a previously uncharacterized pro-metastatic regulator in HCC, and elemene could significantly inhibit circBPTF expression and reduced lung metastasis. Mechanistically, circBPTF acted as a molecular sponge for miR-548m, thereby consequently upregulated the expression of RNA polymerase III subunit G (POLR3G) and zinc finger and BTB domain containing 41 (ZBTB41) in HCC cells. Additionally, the biosynthesis of circBPTF was further governed by RNA-binding proteins HNRNPC and HNRNPU. Furthermore, elemene suppressed circBPTF/miR-548m, leading to the downregulation of POLR3G via inhibition of HNRNPC.

CONCLUSION

This study elucidated that circBPTF could promote HCC lung metastasis and indicated that the downregulation of circBPTF was an important mechanism underlying the anti-HCC effects of elemene.

Pan-cancer analysis reveals immunological and prognostic significance of CCT5 in human tumors

The chaperonin containing TCP1 subunit 5 (CCT5) is believed to function as a tumor driver. However, a systematic pan-cancer analysis of CCT5 is still lacking. Therefore, this study aimed to identify the potential role of CCT5 in different types of tumors. This study comprehensively investigated the gene expression, proteomic expression, immune infiltration, DNA methylation, genetic alterations, correlation with TMB and MSI, drug sensitivity, enrichment analysis, and prognostic significance of CCT5 in 33 different tumors based on the TIMER2.0, GEPIA2, UALCAN, SMART, cBioPortal, GSCA databases, and TCGAplot R package. The results revealed significant CCT5 overexpression in most tumors and was significantly associated with poor OS and DFS in different tumor types. Reduced promoter and N-shore methylation of CCT5, indicating its potential oncogenic and epigenetic roles. Amplification was the most common type of CCT5 alterations. Immune infiltration analysis revealed a strong correlation between CCT5 and different immune cells. CCT5 exhibited a significant correlation with TMB and MSI in KIRC and STAD. Furthermore, enrichment analysis revealed associations between CCT5 and cell cycle pathway and various cellular functions. These findings suggested that CCT5 might serve as a potential prognostic biomarker and target for immunotherapy in various cancers.

RNA-binding proteins and autophagy in lung cancer: mechanistic insights and therapeutic perspectives

BACKGROUND

Lung cancer remains a leading cause of cancer-related mortality worldwide. Its progression is intricately associated with the dynamic regulation of autophagy and RNA-binding proteins (RBPs), which play crucial roles in mRNA stability, alternative splicing, and cellular stress responses.

OBJECTIVES

This review aims to systematically analyze the mechanisms through which RBPs and autophagy contribute to lung cancer progression and explore potential therapeutic strategies targeting these pathways.

METHODS

We reviewed recent studies on the molecular mechanisms by which RBPs regulate tumor proliferation, metabolic adaptation, and their interaction with autophagy. The review also examines the dual roles of autophagy in lung cancer, highlighting its context-dependent effects on cell survival and death.

RESULTS

The interactions and regulatory networks between RBPs and autophagy involve multiple levels of regulation. RBPs can directly influence autophagy processes and act as microRNA (miRNA) sponges to regulate mRNA stability. The modulation of RBPs affects the expression of autophagy-related genes (ATGs) and autophagosome formation. Additionally, RBPs participate in complex regulatory interactions with non-coding RNAs (ncRNAs), including long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and other proteins.

CONCLUSIONS

This review proposes innovative therapeutic strategies that combine RBP-targeting approaches (e.g., small molecule inhibitors, CRISPR gene editing) with autophagy modulators (e.g., mTOR inhibitors, chloroquine) to enhance treatment efficacy. Nanoparticle drug delivery systems and epigenetic regulation offer further opportunities for targeted interventions. This review lays a theoretical foundation for advancing lung cancer research and provides novel insights into synergistic therapies that target both RBPs and autophagy to improve treatment outcomes for lung cancer.

The impact of an RNA-binding protein group on regulating the RSPO-LGR4/5-ZNRF3/RNF43 module and the immune microenvironment in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality. RNA-binding proteins (RBPs) are potential therapeutic targets because of their role in tumor progression. This study investigated the interactions between specific HCC progression-associated RBPs (HPARBPs), namely, ILF3, PTBP1, U2AF2, NCBP2, RPS3, and SSB, in HCC and their downstream targets, as well as their impact on the immune microenvironment and their clinical value.

METHODS

Tissue samples from human HCC, collected from 28 patients who experienced recurrence following postoperative adjuvant therapy were examined. The mRNA levels of RBPs and their prospective targets were quantified through RNA isolation and quantitative real-time PCR. Data from two public datasets were scrutinized for both expression and clinical relevance. Through Student's t test and logistic regression, HPARBPs were identified. Enhanced cross-linking immunoprecipitation (eCLIP) experiments revealed RBP-RNA interactions in HepG2 cells. For functional enrichment, Metascape was used, whereas CIBERSORT was used to characterize the immune microenvironment.

RESULTS

Public database analysis confirmed widespread RBP expression abnormalities in HCC (false discovery rate < 0.00001 and fold change ≥ 1.15 or ≤ 0.85), leading to the identification of 42 HPARBPs and core modules. eCLIP data analysis revealed the specificity of downstream target genes and binding site features for core HPARBPs (signal value > 3, P value < 0.01). Four core HPARBPs may bind to RNAs of genes in the RSPO-LGR4/5-ZNRF3/RNF43 module, affecting the Wnt pathway and HCC progression. Immunoinfiltration analysis revealed changes in the HCC immune microenvironment due to altered expression of relevant genes.

CONCLUSION

In our study, we identified core HPARBPs that might contribute to HCC progression by binding to RNAs in the RSPO-LGR4/5-ZNRF3/RNF43 module. Changes in the expression of HPARBPs affect the HCC immune microenvironment. Our findings offer novel insights into the regulatory network of Wnt pathway-related RBPs and their potential clinical value in HCC.

ELK4 transcription promotes MSI2-mediated progression of non-small cell lung cancer through the TGF-β/SMAD3 pathway

Non-small cell lung cancer (NSCLC) is a primary contributor to global cancer-related mortality. Musashi-2 (MSI2), an RNA-binding protein (RBP), is upregulated in specific NSCLC tumor subgroups. The current investigation evaluated the role and underlying mechanism of MSI2 in NSCLC. The expression levels of ELK4, MSI2, SMAD3, p-SMAD3 and TGFβR1 were assessed via RT-qPCR or Western blot. Chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays were used to confirm the interaction between ELK4 and MSI2. The proliferation, migration and invasion of NSCLC cells were determined via MTT, colony formation, and transwell assays, respectively. A xenograft tumor model was established in BALB/c nude mice. Immunohistochemical (IHC) staining was used to test Ki67 expression. We found that MSI2 and ELK4 expression levels were increased in NSCLC tissues and cells. ELK4 depletion suppressed the proliferation, migration and invasion of NSCLC cells. ELK4 acts as a transcription factor and promotes the transcription of MSI2. MSI2 depletion repressed NSCLC cell proliferation, migration and invasion through the TGF-β/SMAD3 pathway. Overexpression of ELK4 reversed the inhibitory effect of MSI2 repression on NSCLC progression. These results confirmed that ELK4 is a direct regulator of MSI2 expression and that MSI2 promotes NSCLC progression through TGF-β/SMAD3 activation, suggesting the potential clinical value of inhibiting MSI2 in NSCLC.

Post-Transcriptional Regulation of Gene Expression and the Intricate Life of Eukaryotic mRNAs

In recent years, there has been a growing appreciation for how regulatory events that occur either co- or post-transcriptionally contribute to the control of gene expression. Messenger RNAs (mRNAs) are extensively regulated throughout their metabolism in a precise spatiotemporal manner that requires sophisticated molecular mechanisms for cell-type-specific gene expression, which dictates cell function. Moreover, dysfunction at any of these steps can result in a variety of human diseases, including cancers, muscular atrophies, and neurological diseases. This review summarizes the steps of the central dogma of molecular biology, focusing on the post-transcriptional regulation of gene expression.

Targeting RBM39 suppresses tumor growth and sensitizes osteosarcoma cells to cisplatin

Osteosarcoma is one of the most common malignant primary bone tumors and lacks effective therapeutic targets. Recent studies have reported that RNA binding proteins (RBPs) could serve as promising therapeutic targets for cancers, as their critical roles in transcriptional regulation and RNA splicing. Nevertheless, the potential of pharmacologically inhibiting RBPs as a therapeutic strategy for patients with osteosarcoma remains unclear. In this study, we identified the RNA-binding protein RBM39 as a promising therapeutic target for osteosarcoma. RBM39 is essential for cell viability, and a higher expression of RBM39 was associated with poor prognosis in osteosarcoma. Mechanistically, RBM39 served as a coactivator of c-Jun to transcriptionally upregulate DKK1, leading to the activation of the GSK3β-NF-κB pathway. Importantly, our results reveal that the pharmacological depletion of RBM39 by using the anti-cancer aryl sulfonamide (E7820), a drug known for its oral bioavailability and safe administration, effectively represses osteosarcoma growth and sensitizes osteosarcoma cells to cisplatin treatment both in vitro and in vivo. Our findings unveil the crucial role of RBM39 in modulating tumor growth and cisplatin sensitivity in osteosarcoma cells, suggesting that the combination of aryl sulfonamides with cisplatin may benefit patients with osteosarcoma.

Hsa_circ_0001756 drives gastric cancer glycolysis by increasing the expression and stability of PGK1 mRNA

Introduction

Strategies for preventing high glycolysis in tumour cells are urgently needed. CircRNAs (circRNAs) play important roles in glycolysis. However, the mechanism underlying the effects of hsa_circ_0001756 in gastric cancer (GC) remains unclear.

Methods

In this study, we detected the expression of hsa_circ_0001756 in GC tissues and cells using quantitative real-time polymerase chain reaction (qRT PCR). Construct a silencing and overexpression vector to validate the role of hsa_circ_0001756 in GC. Pulldown and RIP experiments were conducted to verify the identification of miRNA and protein binding to hsa_circ_0001756.

Results

The expression level of hsa_circ_0001756 in GC tissues and cells is significantly upregulated. The expression level of hsa_circ_0001756 is closely related to TNM stage and tumour size in patients with GC. The proliferation and migration of hsa_circ_0001756-expressing cells in vitro were assessed by functional experiments. Hsa_circ_0001756 was found to not only promote the expression and stability of PGK1 by binding with polypyrimidine tract-binding protein 1 (PTBP1) but also promote glycolysis through the miR-185-3P/PGK1 pathway. We found that the regulatory relationships of competing endogenous RNA (ceRNA) and RNA-binding proteins (RBPs) with hsa_circ_0001756may affect glycolysis in GC.

Conclusion

This study provides a theoretical basis for designing drugs that target molecules related to energy metabolism in tumours and provides a new strategy for the clinical treatment of GC.

ZCCHC4 regulates esophageal cancer progression and cisplatin resistance through ROS/c-myc axis

Zinc finger CCHC-type containing 4 (ZCCHC4) is a newly discovered N6-methyladenosine (m6A) RNA methyltransferase (MTase), which possesses an m6A MTase domain and an RNA-binding protein (RBP) Znf domain. Aberrantly expressed ZCCHC4 has been found to be correlated with poor prognosis and chemoresistance in various tumors, such as hepatocellular carcinoma, lung cancer and colorectal cancer. However, the expression and functional analysis of the role of ZCCHC4 in esophageal cancer (ESCA) is still elusive. The expression of ZCCHC4 in esophageal cancer tissues was evaluated by qPT-PCR and western blot. Serum esophageal tumor markers are detected by electrochemiluminescence immunoassay. Relationship between ZCCHC4 expression and pathway enrichment analysis were analyzed by R. The reactive oxygen species (ROS), cell proliferation, cell cycle and apoptosis of ZCCHC4 in esophageal squamous cell carcinoma (ESCC) cells tested by CCK8 assay and flow cytometry assay. Aberrant expression of ZCCHC4 is associated with cancer stages, lymph node metastasis (LNM), and tumor histology, and poorer Overall Survival (OS) in esophageal cancer. The mRNA level of ZCCHC4 in esophageal cancer patients correlates with serum carcinoembryonic antigen (CEA) levels, Squamous Cell Carcinoma (SCC) markers, and tissue polypeptide antigen (TPA) levels. Knockdown of ZCCHC4 induces DNA damage, leading to an elevation of reactive oxygen species (ROS), which in turn triggers S-phase arrest, enhances apoptosis, augments sensitivity to cisplatin treatment, and inhibits proliferation in esophageal cancer cells. Conversely, overexpression of ZCCHC4 promotes proliferation, inhibits apoptosis, and increases resistance to cisplatin in esophageal cancer cells. Furthermore, scavenging ROS reverses the effects of ZCCHC4 downregulation on both proliferation and apoptosis in esophageal cancer cells. Additionally, downregulation of ZCCHC4 inhibits the progression of esophageal cancer and reduces cisplatin resistance in vivo. In summary, downregulation of ZCCHC4 leads to increased sensitivity of ESCC cells to cisplatin, inhibits proliferation, and promotes apoptosis in esophageal cancer cells, potentially via the ROS/c-myc axis. The study suggests a potential adjunctive role for ZCCHC4 in the diagnosis and treatment of esophageal cancer and aids in further understanding the underlying mechanisms in ESCA progression.

Insulin-Like Growth Factor 2 mRNA-Binding Protein 2 (IGF2BP2) Promotes Castration-Resistant Prostate Cancer Progression by Regulating AR-V7 mRNA Stability

BACKGROUND

The emergence of constitutively active androgen receptor (AR) splice variant AR-V7 poses a formidable challenge in treating prostate cancer, as it lacks the ligand binding region targeted by androgen-deprivation therapies such as enzalutamide and abiraterone. AR-V7 is critical for castration-resistant prostate cancer (CRPC) development and progression; however, the molecular mechanisms regulating its expression and biological function remain poorly understood. Here, we investigate the role of IGF2BP2 in regulating AR-V7 expression and CRPC progression.

METHODS

To determine the clinical relevance of IGF2BP2 in CRPC, we analyzed the mRNA expression data for prostate cancer patients available in the Genomic Data Commons (GDC) Data Portal and cBioPortal. Next to investigate the role of IGF2BP2 in regulating AR-V7 expression and enzalutamide resistance, we performed shRNA-mediated IGF2BP2 knockdown and overexpression experiments followed by qRT-PCR, immunoblot, colony-formation, and MTT assays. Finally, we performed RIP-qPCR, actinomycin-D, and IGF2BP2 domain-deletion analysis to study the mechanism by which IGF2BP2 regulates AR-V7 stability, expression, and enzalutamide resistance in CRPC cells.

RESULTS

Our analysis revealed that IGF2BP2 is upregulated in CRPC patients and its expression positively correlates with increasing Gleason score in patients with CRPC. We demonstrate that IGF2BP2 silencing leads to downregulation of AR-V7 and its downstream target genes without affecting AR levels. Additionally, IGF2BP2 knockdown also enhances the sensitivity of CRPC cells to enzalutamide while overexpression increases AR-V7 expression and confers increased resistance to enzalutamide. Mechanistically, our experiments demonstrate that IGF2BP2 binds to the intronic splicing enhancer (ISE) region of AR-V7, thereby enhancing its mRNA stability. Furthermore, our domain-deletion analysis pinpoints the role of KH3 and KH4 domains of IGF2BP2 in regulating AR-V7 stability and enzalutamide resistance.

CONCLUSIONS

Taken together, our findings suggest that IGF2BP2 plays a critical role in regulating AR-V7 expression and stability, offering a novel target for developing therapeutic interventions for CRPC.

Regulatory roles of RNA binding proteins in the Hippo pathway

The Hippo pathway represents a highly conserved evolutionary pathway, dysfunction of which has been implicated in various diseases. RNA-binding proteins (RBPs) intricately modulate gene expression through interacting with non-coding RNAs or other proteins. To data, while an array of RBPs have been identified as modulators of the Hippo pathway, there remains a notable absence of a comprehensive review addressing the mechanistic regulations of RBPs in the transduction of Hippo signaling. Herein, this review aims to consolidate recent advances and elucidate the intricate mechanisms underlying RBPs binding to target RNA. It also explores the dynamic interplay between RBPs, non-coding RNAs, TFs, and DNA on chromatin. Additionally, it also outlines future perspectives, including the essential non-canonical functions of RBPs and emerging roles of non-canonical RBPs as transcription factors (TFs) in genes transcription. Overall, this review provides mechanistic insights into the roles of eukaryotic RBP proteins in the regulation of crucial signaling cascades.

RNA binding protein ILF3 increases CEP55 mRNA stability to enhance malignant potential of breast cancer cells and suppress ferroptosis

BACKGROUND

Ferroptosis has emerged as a promising therapeutic target in cancer treatment. CEP55, a key regulator of cell mitosis, plays a significant role in the tumorigenesis of many malignancies. In this study, we elucidated the function of CEP55 in the ferroptosis of breast cancer (BC).

METHODS

The protein levels of CEP55 and ILF3 were detected by immunoblotting or immunohistochemistry, and their mRNA levels were assessed by quantitative PCR. Cell invasion and migration were evaluated by transwell assay. Cell apoptosis and colony formation were tested by flow cytometry and colony formation assays, respectively. RNA immunoprecipitation (RIP) experiment and CEP55 mRNA stability assay were used to validate the relationship between ILF3 and CEP55 mRNA. Subcutaneous xenograft studies were performed to analyze the role of ILF3 depletion in tumor growth.

RESULTS

CEP55 and ILF3 were upregulated in most of human BC samples and MDA-MB-231 and MCF-7 BC cells. The depletion of CEP55 or ILF3 impaired the growth, invasion, and migration of MDA-MB-231 and MCF-7 cells, while promoted their ferroptosis and apoptosis. Mechanistically, ILF3 stabilized CEP55 mRNA to regulate CEP55 expression in BC cells. CEP55 restoration partially rescued the malignant potential defects of ILF3-depleted BC cells and attenuates their ferroptosis. Moreover, ILF3 depletion enhanced the anti-tumor growth activity of the ferroptosis inducer erastin in MDA-MB-231 subcutaneous xenograft tumors.

CONCLUSION

Our observations indicate that the depletion of ILF3 impairs the malignant potential of BC cells and promotes their ferroptosis by downregulating CEP55 expression. Silencing ILF3 or CEP55 could represent a potential therapeutic strategy for BC treatment.

mRNA Transcript Variants Expressed in Mammalian Cells

Gene expression or gene regulation studies often assume one gene expresses one mRNA. However, contrary to the conventional idea, a single gene in mammalian cells can express multiple transcript variants translated into several different proteins. The transcript variants are generated through transcription from alternative start sites and alternative post-transcriptional processing of the precursor mRNA (pre-mRNA). In addition, gene mutations and RNA editing further enhance the diversity of the transcript variants. The transcript variants can encode proteins with various domains, expanding the functional repertoire of a single gene. Some transcript variants may not encode proteins but function as non-coding RNAs and regulate gene expression. The expression level of the transcript variants may vary between cell types or within the same cells under different biological conditions. Transcript variants are characteristic of cell differentiation in a particular tissue, and the variants may play a key role in normal development and aging. Studies also reported that some transcript variants may have roles in disease pathogenesis. The biological significances urge studying the complexity of gene expression at the transcript level. This article updates the molecular basis of transcript variants in mammalian cells, including the formation mechanisms and potential roles in host biology. Gaining insight into the transcript variants will not only identify novel mechanisms of gene regulation but also unravel the role of the variants in health and disease.

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.

Exosomal lncRNAs as diagnostic and therapeutic targets in multiple myeloma

Multiple Myeloma (MM) is the second most common malignancy of the hematopoietic system, accounting for approximately 10% of all hematological malignancies, and currently, there is no complete cure. Existing research indicates that exosomal long non-coding RNAs (lncRNAs) play a crucial regulatory role in the initiation and progression of tumors, involving various interactions such as lncRNA-miRNA, lncRNA-mRNA, and lncRNA-RNA binding proteins (RBP). Despite the significant clinical application potential of exosomal lncRNAs, research in this area still faces challenges due to their low abundance and technical limitations. To our knowledge, this review is the first to comprehensively integrate and elucidate the three mechanisms of action of exosomal lncRNAs in MM, and to propose potential therapeutic targets and clinical cases based on these mechanisms. We highlight the latest advancements in the potential of exosomal lncRNAs as biomarkers and therapeutic targets, offering not only a comprehensive analysis of the role of exosomal lncRNAs in MM but also new perspectives and methods for future clinical diagnosis and treatment of multiple myeloma.

hnRNPLL regulates MYOF alternative splicing and correlates with early metastasis in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a deadly cancer known for its high rate of early metastasis, necessitating the discovery of the underlying mechanisms. Herein, we report that heterogeneous nuclear ribonucleoprotein L-like (hnRNPLL) expression significantly increases at the invasion forefront in PDAC and is associated with early metastasis and poor prognosis. Our findings revealed that hnRNPLL knockdown resulted in extensive exon skipping (ES) events. In particular, we identified myoferlin (MYOF), a member of the ferlin family involved in membrane processes, as a functional splicing target of hnRNPLL. hnRNPLL depletion stimulates MYOF exon 17 retention to reduce the short isoform of MYOF (MYOFb) and inhibit metastasis. In contrast, hnRNPLL or MYOFb overexpression promoted pancreatic cancer cell migration and invasion. These results suggest that hnRNPLL is a critical factor for early PDAC metastasis. hnRNPLL and MYOFb may be potential therapeutic targets for PDAC.

RBM19 promotes the progression of prostate cancer under docetaxel treatment via SNHG21/PIM1 axis

RBM family proteins plays the critical role in the progression of numerous tumors. However, whether RBM family proteins involved in prostate cancer (PCa) progression is remain elucidated. In our study, an RNAi screen containing shRNA library targeting 54 members of the RBM family was applied to identify the critical RBM proteins involved in prostate cancer progression under docetaxel treatment, and RBM19 was selected. RBM19 was up-regulated in PCa specimens and correlated with the prognosis and Gleason score of PCa patients. Functionally assays revealed that RBM19 promoted PCa progression under docetaxel treatment both in vivo and in vitro. Mechanistically, RBM19 could bind to LncRNA SNHG21, thereby increased SNHG21 expression through enhancing its stability. Furthermore, SNHG21 bind to PIM1 proteins and prevented it from ubiquitin-protease dependent degradation and ultimately enhancing mitochondrial homeostasis. Overall, our study indicates the RBM19/SNHG21/PIM1 axis may be the encouraging target for docetaxel-tolerance PCa treatment.

SNRNP70 regulates the splicing of CD55 to promote osteosarcoma progression

Osteosarcoma (OS) is the most common malignant bone tumor, characterized by a high propensity for metastasis. Recent studies have highlighted the role of alternative splicing in cancer metastasis, although the precise mechanisms underlying aberrant splicing in OS invasion and metastasis remain unclear. Here, we analyzed consistently differentially expressed genes and differentially alternative splicing events between primary and metastatic OS to identify potential genes associated with OS progression. U1 small nuclear ribonucleoprotein 70K (SNRNP70) emerged as both differentially expressed and spliced, with elevated SNRNP70 levels correlating with poor prognosis in pateints with OS. Functional experiments demonstrated that SNRNP70 overexpression enhanced the proliferation and metastasis of OS cells in vitro, while its depletion reduced these capabilities in vivo. Mechanistically, SNRNP70 directly interacted with CD55, modulating its alternative splicing and promoting tumor progression in OS. Additionally, metastatic OS samples exhibited increased infiltration of resting immune cells, and single-cell RNA sequencing revealed communication between SNRNP70-expressing osteoblastic cells and macrophages via the ADGRE5/CD55 signaling pathway. Overall, our results showed that SNRNP70 knockdown inhibited OS progression, which was associated with the splicing of CD55, indicating SNRNP70 as a promising target for OS treatment.

Identification of RNA-binding protein RBMS3 as a potential biomarker for immunotherapy in bladder cancer

RNA-binding protein (RBP) plays pivotal roles in the malignant progression of cancer by regulating gene expression. In this paper, we aimed to develop RBP-based prognostic signature and identify critical hub RBPs in bladder cancer (BLCA). Firstly, a risk model based on differentially expressed RBP gens (DERBPs) between normal and tumor tissues was successfully established, which can predict the tumor stromal score and drug sensitivity. Then two another RBP risk models based on miRNA-correlated RBPs or lncRNA-correlated RBPs were also established, and RBMS3 was identified as the overlapping gene in the three models. Data from multiple bioinformatics databases revealed that RBMS3 was an independent prognostic factor for overall survival (OS), and was associated with an immunosuppressive tumor microenvironment (TME) in BLCA. Further, Single-cell RNA-Seq (scRNA-Seq) data and the human protein altas (HPA) database showed that RBMS3 expression (both mRNA and protein) were up-regulated in BLCA tumor and tumor stromal cells. Finally, RBMS3 was shown to be associated with worse response to BLCA immunotherapy. Overall, RBMS3 is a key prognostic RBP with TME remodeling function and may serve as a target for BLCA immunotherapy.

Epithelial-mesenchymal transition to mitigate age-related progression in lung cancer

Epithelial-Mesenchymal Transition (EMT) is a fundamental biological process involved in embryonic development, wound healing, and cancer progression. In lung cancer, EMT is a key regulator of invasion and metastasis, significantly contributing to the fatal progression of the disease. Age-related factors such as cellular senescence, chronic inflammation, and epigenetic alterations exacerbate EMT, accelerating lung cancer development in the elderly. This review describes the complex mechanism among EMT and age-related pathways, highlighting key regulators such as TGF-β, WNT/β-catenin, NOTCH, and Hedgehog signalling. We also discuss the mechanisms by which oxidative stress, mediated through pathways involving NRF2 and ROS, telomere attrition, regulated by telomerase activity and shelterin complex, and immune system dysregulation, driven by alterations in cytokine profiles and immune cell senescence, upregulate or downregulate EMT induction. Additionally, we highlighted pathways of transcription such as SNAIL, TWIST, ZEB, SIRT1, TP53, NF-κB, and miRNAs regulating these processes. Understanding these mechanisms, we highlight potential therapeutic interventions targeting these critical molecules and pathways.

The noncanonical RNA-binding protein RAN stabilizes the mRNA of intranuclear stress granule assembly factor G3BP1 in nasopharyngeal carcinoma

RNA-binding proteins (RBPs) play critical roles in tumor progression by participating in the posttranscriptional regulation of RNA. However, the levels and function of RBPs in nasopharyngeal carcinoma (NPC) remain elusive. Here we identified a noncanonical RBP RAN that has the most significant role in NPC progression by a small siRNA pool screening. Functionally, RAN facilitates NPC proliferation and metastasis in vitro and in vivo. High levels of RAN are associated with poor prognosis of NPC patients and can be performed as a prognostic biomarker. Mechanistically, RAN increases the nucleus import of TDP43 and enhances TDP43 nuclear distribution. On the other hand, RAN is directly bound to the coding sequence of G3BP1 mRNA and serves as an adapter to facilitate TDP43 interacting with G3BP1 mRNA 3' UTR. These contribute to increasing G3BP1 mRNA stability in the nucleus and lead to upregulation of G3BP1, which further enhances AKT and ERK signaling and ultimately promotes NPC proliferation and metastasis. These findings reveal that RAN stabilizes intranuclear G3BP1 mRNA by dual mechanisms: recruiting TDP43 into the nucleus and enhancing its interaction with G3BP1 mRNA, suggesting a critical role of RAN in NPC progression and providing a new regulation framework of RBP-RNA.

RNA binding protein RBM22 suppresses non-small cell lung cancer tumorigenesis by stabilizing LATS1 mRNA

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related mortality worldwide. Despite advancements in diagnostics and therapeutics, the prognosis for NSCLC remains poor, highlighting the urgent need for novel treatment options. RNA binding proteins, particularly RBM22, have emerged as significant contributors to cancer progression by influencing RNA splicing and gene expression. This study investigates the role of RBM22 in NSCLC and its potential as a therapeutic target. We focus on the effects of RBM22 on cell proliferation, invasion, stemness, and its interaction with LATS1 mRNA. RBM22 expression was assessed in samples and cell lines of NSCLC through techniques such as real-time PCR and western blot analysis. To modify RBM22 levels, overexpression and knockdown methods were employed utilizing vectors and siRNAs. We conducted assays for cell proliferation, invasion, and stemness to evaluate the effects of altering RBM22. The interaction between RBM22 and LATS1 mRNA was investigated using RNA immunoprecipitation. In addition, in vivo studies involving subdermal tumor and lung metastasis models in athymic mice were carried out to evaluate how changes in RBM22 influence the tumorigenic and metastatic characteristics of NSCLC. Our analysis revealed a significant underexpression of RBM22 in NSCLC tissues compared to adjacent healthy tissues. Increasing RBM22 expression in NSCLC cell lines led to a marked decrease in cellular proliferation, invasiveness, and stemness, while silencing RBM22 produced opposing effects. Further investigations confirmed that RBM22 directly interacts with LATS1 mRNA, thereby stabilizing and enhancing its expression. In vivo studies validated that elevated RBM22 expression substantially reduced tumor formation and pulmonary metastases, as evidenced by decreased tumor size, mass, and Ki-67 proliferation marker expression, along with a significant reduction in the number of metastatic nodules in the lungs. Our study demonstrates that RBM22 suppresses NSCLC by stabilizing LATS1 mRNA, which in turn reduces tumor growth and metastasis. Consequently, RBM22 emerges as a valuable therapeutic target for NSCLC, offering new strategies for addressing this challenging condition.

circUBE2G1 interacts with hnRNPU to promote VEGF-C-mediated lymph node metastasis of lung adenocarcinoma

Background

Patients with lymph node(LN)metastasis-positive Lung adenocarcinoma(LUAD)suffer from a significantly reduced five-year survival rate. Increasing evidence indicates circular RNAs(circRNAs)play crucial roles in regulating cancer progression. However, the specific regulatory mechanisms of circRNAs in the LN metastasis of LUAD have not been fully explored.

Methods

GEO datasets and sequence analysis were applied for the identification of differentially expressed circRNAs between LUAD tissues and adjacent normal tissues. In vitro and in vivo experiments were performed to evaluate the function of circUBE2G1. The interaction between circUBE2G1 and VEGF-C was determined by RNA pulldown, ChIP, ChIRP and luciferase assays.

Results

In this study, we identified a novel circRNA, circUBE2G1 (hsa_circ_0041555), which is upregulated in LUAD and positively correlated with LN metastasis in patients with LUAD. Functionally, overexpression of circUBE2G1 promotes lymphangiogenesis and LN metastasis of LUAD both in vitro and in vivo. Mechanistically, circUBE2G1 activates the transcription of vascular endothelial growth factor C (VEGF-C) by recruiting hnRNPU to enhance H3K27ac on the VEGF-C promoter, thereby facilitating lymphangiogenesis and LN metastasis in LUAD.

Conclusion

Our findings offer new insights into the mechanisms behind circRNA-mediated LN metastasis in LUAD and suggest that circUBE2G1 may serve as a potential therapeutic target for LN metastasis in LUAD.

KHDRBS1 regulates the pentose phosphate pathway and malignancy of GBM through SNORD51-mediated polyadenylation of ZBED6 pre-mRNA

Glioblastoma is one of the most common and aggressive primary brain tumors. The aberration of metabolism is the important character of GBM cells and is tightly related to the malignancy of GBM. We mainly verified the regulatory effects of KHDRBS1, SNORD51 and ZBED6 on pentose phosphate pathway and malignant biological behavior in glioblastoma cells, such as proliferation, migration and invasion. KHDRBS1 and SNORD51 were upregulated in GBM tissues and cells. But ZBED6 had opposite tendency in GBM tissues and cells. KHDRBS1 may improve the stability of SNORD51 by binding to SNORD51, thus elevating the expression of SNORD51. More importantly, SNORD51 can competitively bind to WDR33 with 3'UTR of ZBED6 pre-mRNA which can inhibit the 3' end processing of ZBED6 pre-mRNA, thereby inhibiting the expression of ZBED6 mRNA. ZBED6 inhibited the transcription of G6PD by binding to the promoter region of G6PD. Therefore, the KHDRBS1/SNORD51/ZBED6 pathway performs an important part in regulating the pentose phosphate pathway to influence malignant biological behavior of GBM cells, providing new insights and potential targets for the treatment of GBM.

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.

Exploring the roles and molecular mechanisms of RNA binding proteins in the sorting of noncoding RNAs into exosomes during tumor progression

BACKGROUND

RNA binding proteins (RBPs) play a role in sorting non-coding RNAs (ncRNAs) into exosomes. These ncRNAs, carried by exosomes, are involved in regulating various aspects of tumor progression, including metastasis, angiogenesis, control of the tumor microenvironment, and drug resistance. Recent studies have emphasized the importance of the RBP-ncRNA-exosome mechanism in tumor regulation.

AIM OF REVIEW

This comprehensive review aims to explore the RBP-ncRNA-exosome mechanism and its influence on tumor development. By understanding this intricate mechanism provides novel insights into tumor regulation and may lead to innovative treatment strategies in the future.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The review discusses the formation of exosomes and the complex relationships among RBPs, ncRNAs, and exosomes. The RBP-ncRNA-exosome mechanism is shown to affect various aspects of tumor biology, including metastasis, multidrug resistance, angiogenesis, the immunosuppressive microenvironment, and tumor progression. Tumor development relies on the transmission of information between cells, with RBPs selectively mediating sorting of ncRNAs into exosomes through various mechanisms, which in turn carry ncRNAs to regulate RBPs. The review also provides an overview of potential therapeutic strategies, such as targeted drug discovery and genetic engineering for modifying therapeutic exosomes, which hold great promise for improving cancer treatment.

Circular RNA circWBSCR22 facilitates colorectal cancer metastasis by enhancing CHD4's protein stability

Widespread metastases continue to be a massive challenge for colorectal cancer (CRC) therapy and contribute to the high mortality rate in patients with CRC. Circular RNAs (circRNAs) are a novel group of endogenous RNAs identified as agents modulating tumorigenesis and aggressiveness with tissue heterogeneity. However, the biological functions of circRNAs in CRC metastasis remain largely unknown. Here, we identified that circWBSCR22, a novel circRNA back-spliced from the WBSCR22 pre-mRNA, was significantly elevated in CRC tissue compared with adjacent normal tissue. Further gain- and loss-of-function assays manifested that circWBSCR22 promotes epithelial-mesenchymal transition (EMT) and metastasis in vitro and in vivo, which are mediated by the chromodomain helicase-DNA-binding protein 4 (CHD4) protein. Mechanically, circWBSCR22 binds directly to up-frameshift protein 1 (UPF1), an RNA binding protein recognized for its function in RNA surveillance, and hinders its role in directing CHD4 protein ubiquitination for degradation. Consequently, by stabilizing the CHD4 protein, circWBSCR22 hastens the development and metastasis of CRC. Therefore, our findings first delineate the oncogenic role and mechanism of circWBSCR22 in CRC growth and metastasis and its potential to serve as a therapeutic target for CRC.

Fibrillarin reprograms glucose metabolism by driving the enhancer-mediated transcription of PFKFB4 in liver cancer

DNA- and RNA-binding proteins (DRBPs) are versatile proteins capable of binding to both DNA and RNA molecules. In this study, we identified fibrillarin (FBL) as a key DRBP that is upregulated in liver cancer tissues vs. normal tissues and is correlated with patient prognosis. FBL promotes the proliferation of liver cancer cells both in vitro and in vivo. Mechanistically, FBL interacts with the transcription factor KHSRP, thereby regulating the expression of genes involved in glucose metabolism and leading to the reprogramming of glucose metabolism. Specifically, FBL and KHSRP work together to transcriptionally activate the glycolytic enzyme PFKFB4 by co-occupying enhancer and promoter elements, thereby further promoting liver cancer growth. Collectively, these findings provide compelling evidence highlighting the role of FBL as a transcriptional regulator in liver cancer cells, working in conjunction with KHSRP. The FBL/KHSRP-PFKFB4 regulatory axis holds potential as both a prognostic indicator and a therapeutic target for liver cancer. SIGNIFICANCE: A novel role of FBL in the transcriptional activation of PFKFB4, leading to glucose metabolism reprogramming in liver cancer.

HNRNPC modulates PKM alternative splicing via m6A methylation, upregulating PKM2 expression to promote aerobic glycolysis in papillary thyroid carcinoma and drive malignant progression

The heterogeneous nuclear ribonucleoprotein C (HNRNPC) plays a crucial role in tumorigenesis, yet its role in papillary thyroid carcinoma (PTC) remains elusive. Herein, we elucidated the function and molecular mechanism of HNRNPC in PTC tumorigenesis and progression. Our study unveiled a significant upregulation of HNRNPC in PTC, and knockdown of HNRNPC markedly inhibited the proliferation, invasion, and metastasis of BCPAP cells. Furthermore, HNRNPC modulated PKM alternative splicing in BCPAP cells primarily through m6A modification. Additionally, by upregulating PKM2 expression, HNRNPC promoted aerobic glycolysis in BCPAP cells, thereby facilitating malignant progression in PTC. In summary, our findings demonstrate that HNRNPC regulates PKM alternative splicing through m6A methylation modification and promotes the proliferation, invasion and metastasis of PTC through glucose metabolism pathways mediated by PKM2. These discoveries provide new biomarkers for screening and diagnosing PTC patients and offer novel therapeutic targets for personalized treatment strategies.

Global RNA Interaction and Transcriptome Profiles Demonstrate the Potential Anti-Oncogenic Targets and Pathways of RBM6 in HeLa Cells

BACKGROUND

The fate and functions of RNAs are coordinately regulated by RNA-binding proteins (RBPs), which are often dysregulated in various cancers. Known as a splicing regulator, RNA-binding motif protein 6 (RBM6) harbors tumor-suppressor activity in many cancers; however, there is a lack of research on the molecular targets and regulatory mechanisms of RBM6.

METHODS

In this study, we constructed an RBM6 knock-down (shRBM6) model in the HeLa cell line to investigate its functions and molecular targets. Then we applied improved RNA immunoprecipitation coupled with sequencing (iRIP-seq) and whole transcriptome sequencing approaches to investigate the potential role and RNA targets of RBM6.

RESULTS

Using The Cancer Genome Atlas dataset, we found that higher expression of RBM6 is associated with a better prognosis in many cancer types. In addition, we found that RBM6 knockdown promoted cell proliferation and inhibited apoptosis, demonstrating that RBM6 may act as an anti-oncogenic protein in cancer cells. RBM6 can regulate the alternative splicing (AS) of genes involved in DNA damage response, proliferation, and apoptosis-associated pathways. Meanwhile, RBM6 knockdown activated type I interferon signaling pathways and inhibited the expression of genes involved in the cell cycle, cellular responses to DNA damage, and DNA repair pathways. The differentially expressed genes (DEGs) by shRBM6 and their involved pathways were likely regulated by the transcription factors undergoing aberrant AS by RBM6 knockdown. For iRIP-seq analysis, we found that RBM6 could interact with a large number of mRNAs, with a tendency for binding motifs GGCGAUG and CUCU. RBM6 bound to the mRNA of cell proliferation- and apoptosis-associated genes with dysregulated AS after RBM6 knockdown.

CONCLUSIONS

In summary, our study highlights the important role of RBM6, as well as the downstream targets and regulated pathways, suggesting the potential regulatory mechanisms of RBM6 in the development of cancer.

Hsa_circ_ROBO1 competes with miR-324-3p and upregulates NME1 to promote tumor metastasis in nasopharyngeal carcinoma

BACKGROUND

This work aims to explore circ_ROBO1's function in nasopharyngeal carcinoma (NPC).

METHODS

circ_ROBO1 expression in NPC tissues and cell lines was measured. The regulation of circ_ROBO1 and/or miR-324-3p on the proliferation, migration, invasion, and apoptosis of NPC cells was investigated by functional experiments. The interplay between circ_ROBO1, miR-324-3p, and NME1 was explored. Tumor growth and metastasis were studied in mice.

RESULTS

circ_ROBO1 was overexpressed in NPC. Knockdown of circ_ROBO1 repressed proliferation, migration, and invasion and induced apoptosis of NPC cells. Loss of circ_ROBO1 reduced tumor growth and metastasis in mice. circ_ROBO1 competed with miR-324-3p to upregulate NME1. Lowering miR-324-3p expression impaired the effect of knockdown of circ_ROBO1on NPC cells.

CONCLUSION

Overexpressed circ_ROBO1 promotes NPC development by modifying the miR-324-3p/NME1 axis.

The TDP-43/TP63 Positive Feedback Circuit Promotes Esophageal Squamous Cell Carcinoma Progression

Esophageal squamous cell carcinoma (ESCC) is one of the most prevalent malignancies with a 5-year survival rate of only 15% in patients with advanced diseases. Tumor protein 63 (TP63), a master transcription factor (TF) in ESCC, cooperates with other TFs to regulate enhancers and/or promoters of target oncogenes, which in turn promotes tumorigenesis. TAR-DNA-binding protein-43 (TDP-43) is an RNA/DNA binding protein with elevated expression in several neoplasms. However, it remains unclear how TDP-43 contributes to ESCC progression. In this study, TDP-43 is identified as a novel oncogene with markedly upregulated expression in ESCC tissues through profiling expression levels of one hundred and fifty canonical RNA binding protein (RBP) genes in multiple ESCC patient cohorts. Importantly, TDP-43 boosted TP63 expression via post-transcriptionally stabilizing TP63 mRNAs as a RBP and promoting TP63 transcription as a TF binding to the TP63 promoter in ESCC cells. In contrast, the master TF TP63 also bound to the TDP-43 promoter, accelerated TDP-43 transcription, and caused a noticeable increase in TDP-43 expression in ESCC cells. The findings highlight TDP-43 as a viable therapeutic target for ESCC and uncover a hitherto unrecognized TDP-43/TP63 circuit in cancer.

Long non-coding RNA TPT1-AS1 inhibits ferroptosis in ovarian cancer by regulating GPX4 via CREB1 regulation

BACKGROUND

Long non-coding RNAs (lncRNAs) play crucial roles in cellular processes, with dysregulation implicated in various diseases, including cancers. The lncRNA TPT1-AS1 (TPT1 Antisense RNA 1) promotes tumor progression in several cancers, including ovarian cancer (OC), but its influence on ferroptosis and interaction with other proteins remains underexplored.

METHODS

In this study, we employed a multi-faceted approach to investigate the functional significance of TPT1-AS1 in OC. We assessed TPT1-AS1 expression in OC specimens and cell lines using RT-qPCR, in situ hybridization (ISH), and fluorescence in situ hybridization (FISH) assays. Functional assays included evaluating the impact of TPT1-AS1 knockdown on OC cell proliferation, migration, invasiveness, and cell cycle progression. Further, we explored and validated the interaction of TPT1-AS1 with other proteins using bioinformatics. Finally, we investigated TPT1-AS1 involvement in erastin-induced ferroptosis using Iron Assay, Malondialdehyde (MDA) assay, and reactive oxygen species (ROS) detection.

RESULTS

Our findings revealed that TPT1-AS1 overexpression in OC correlated with an unfavorable prognosis. TPT1-AS1 knockdown suppressed cell proliferation, migration, and invasiveness. Additionally, TPT1-AS1 inhibited erastin-induced ferroptosis, and in vivo experiments confirmed its oncogenic impact on tumor development. Mechanistically, TPT1-AS1 was found to regulate Glutathione Peroxidase 4 (GPX4) transcription via CREB1 (cAMP response element-binding protein 1) and interact with RNA-binding protein (RBP) KHDRBS3 (KH RNA Binding Domain Containing, Signal Transduction Associated 3) to regulate CREB1.

CONCLUSION

TPT1-AS1 promotes OC progression by inhibiting ferroptosis and upregulating CREB1, forming a regulatory axis with KHDRBS3. These findings highlight the regulatory network involving lncRNAs, RBPs, and transcription factors in cancer progression.

17β-estradiol in colorectal cancer: friend or foe?

Colorectal cancer (CRC) is a common gastrointestinal malignancy with higher incidence and mortality rates in men compared to women, potentially due to the effects of estrogen signaling. There is substantial evidence supporting the significant role of 17β-Estradiol (E2) in reducing CRC risk in females, although this perspective remains debated. E2 has been demonstrated to inhibit CRC cell proliferation and migration at the cellular level by enhancing DNA mismatch repair, modulating key gene expression, triggering cell cycle arrest, and reducing activity of migration factors. Furthermore, E2 contributes to promote a tumor microenvironment unfavorable for CRC growth by stimulating ERβ expression, reducing inflammatory responses, reversing immunosuppression, and altering the gut microbiome composition. Conversely, under conditions of high oxidative stress, hypoxia, and nutritional deficiencies, E2 may facilitate CRC development through GPER-mediated non-genomic signaling. E2's influence on CRC involves the genomic and non-genomic signals mediated by ERβ and GPER, respectively, leading to its dual roles in anticancer activity and carcinogenesis. This review aims to summarize the potential mechanisms by which E2 directly or indirectly impacts CRC development, providing insights into the phenomenon of sexual dimorphism in CRC and suggesting potential strategies for prevention and treatment.

The oncogenic role and regulatory mechanism of ACAA2 in human ovarian cancer

Acetyl-CoAacyltransferase2 (ACAA2) is a key enzyme in the fatty acid oxidation pathway that catalyzes the final step of mitochondrial β oxidation, which plays an important role in fatty acid metabolism. The expression of ACAA2 is closely related to the occurrence and malignant progression of tumors. However, the function of ACAA2 in ovarian cancer is unclear. The expression level and prognostic value of ACAA2 were analyzed by databases. Gain and loss of function were carried out to explore the function of ACAA2 in ovarian cancer. RNA-seq and bioinformatics methods were applied to illustrate the regulatory mechanism of ACAA2. ACAA2 overexpression promoted the growth, proliferation, migration, and invasion of ovarian cancer, and ACAA2 knockdown inhibited the malignant progression of ovarian cancer as well as the ability of subcutaneous tumor formation in nude mice. At the same time, we found that OGT can induce glycosylation modification of ACAA2 and regulate the karyoplasmic distribution of ACAA2. OGT plays a vital role in ovarian cancer as a function of oncogenes. In addition, through RNA-seq sequencing, we found that ACAA2 regulates the expression of DIXDC1. ACAA2 regulated the malignant progression of ovarian cancer through the WNT/β-Catenin signaling pathway probably. ACAA2 is an oncogene in ovarian cancer and has the potential to be a target for ovarian cancer therapy.

CSDE1: a versatile regulator of gene expression in cancer

RNA-binding proteins (RBPs) have garnered significant attention in the field of cancer due to their ability to modulate diverse tumor traits. Once considered untargetable, RBPs have sparked renewed interest in drug development, particularly in the context of RNA-binding modulators of translation. This review focuses on one such modulator, the protein CSDE1, and its pivotal role in regulating cancer hallmarks. We discuss context-specific functions of CSDE1 in tumor development, its mechanisms of action, and highlight features that support its role as a molecular adaptor. Additionally, we discuss the regulation of CSDE1 itself and its potential value as biomarker and therapeutic target.