Molecular Cancer

Circular RNAs (circRNAs) are an emerging class of RNAs with biomarker potential, but their detection in liquid biopsies is challenging due to low abundance. We developed Ouro-seq, a novel long-read sequencing protocol optimized for full-length circRNA recovery. Applied to urine, cervico-vaginal self-samples from cervical cancer patients, and plasma from lung cancer patients and controls, Ouro-seq recovered 2-5 times more and substantially longer circRNA molecules than conventional methods. Plasma contained predominantly exonic circRNAs, while urine and cervico-vaginal samples were dominated by previously undercharacterized intergenic circRNAs. We also identified extensive alternative circularization and splicing events. Functional analysis revealed distinct specialization patterns: exonic circRNAs showed enhanced miRNA sponging potential, while circRNAs from unplaced genomic scaffolds demonstrated greater peptide-coding capacity. This study establishes Ouro-seq as a valuable tool for comprehensive circRNA characterization in low-yield clinical samples and advances circRNA biology understanding with potential biomarker discovery and disease monitoring applications. MotivationWhile circular RNAs (circRNAs) constitute a minor fraction of total RNA, they may play critical roles in cancer development. CircRNA concentrations are typically too low for detection by Oxford Nanopore Long-Read Sequencing (LRS), particularly in samples with limited RNA content, such as liquid biopsies. Consequently, LRS-based circRNA analysis from liquid biopsies remains unexplored. To overcome these technical limitations, we developed an optimized circRNA enrichment method utilizing short-amplicon suppression, enabling circRNA profiling from urine, plasma, and cervico-vaginal samples.

BackgroundHER2-positive (HER2+) cancers are associated with aggressive tumor development but also high response rates to targeted blockade treatments of the HER-2/neu signaling pathway leading to improved clinical outcome for the patient. Current clinical analysis of the HER2 status primarily relies on solid tumor biopsies low-suitable for continuous real-time monitoring needed for possible adjustment of the treatment, while serum tests targeting blood-circulating HER-2/neu fragments often show conflicting tumor-serum relations. MethodsA cellulase-linked aptamer sandwich assay was used for detection of total urokinase plasminogen activator (uPA) and its different forms in serum of cancer patients and healthy individuals. Serum uPA levels were correlated with solid biopsy results and relevant clinical data extracted from electronic patient records, and FDG-PET/CT scanning. ResultsWe show that serum uPA allows precise stratification of patients with HER2+ cancers and cancers with HER2 borderline expression. Serum levels of total uPA 96.6% accurately informed about HER2+ tumor status in a cohort of 85 patients, with a HER2+ cut-off value of 0.976 ng mL-1. ConclusionsThe established liquid biopsy test for serum uPA has potential for accurate diagnosis and staging of patients with HER2+ cancers and "borderline" cancers requiring further confirmatory (or rejection) testing.

Resistance to cancer treatment remains the leading cause of cancer-related deaths. In tumors with low mutational burden such as pediatric cancers, alternative transcripts, including circular RNAs (circRNAs), have been identified as involved in treatment resistance. However, their isoforms are often missed by commonly used short-read sequencing. Here, we employ long-read sequencing to identify full-length circRNA isoforms associated with resistance in ALK -driven pediatric cancers. Using cell models and a cohort of ALK -translocated anaplastic large-cell lymphoma (ALK+ ALCL) patients, two circRNAs were detected as specifically upregulated in resistant cases and associated with worse disease outcomes. Similar findings were observed in the pediatric cancer neuroblastoma. These circRNAs were also more abundant in liquid biopsies from ALKi-resistant ALK+ ALCL and neuroblastoma patients. This demonstrates that long-read sequencing allows for uncovering disease-relevant circRNA isoforms that could serve as biomarkers for resistance detection in a clinical setting.

MiRNA Epitranscriptomics has placed a new layer of complexity in the cancer field. Despite the fast-growing interest in miRNA editing and shifted miRNA isoforms, a simultaneous study of both modifications in cancer is still missing. Here, we concurrently profiled multiple miRNA modifications, including A-to-I RNA editing and shifted miRNA isoforms, in >13K adult and pediatric tumor samples across 38 distinct cancer cohorts from The Cancer Genome Atlas and The Therapeutically Applicable Research to Generate Effective Treatments datasets. We investigated the differences among canonical miRNAs and the wider miRNAome in terms of expression, clustering, dysregulation, and prognostic standpoint. The combination of canonical miRNAs/miRNA isoforms boosted the quality of clustering results, outlining unique cohorts clinical-pathological features. We described modified miRNAs showing opposite dysregulation with respect to their canonical counterparts in cancer, potentially impacting their targetome and function. The abundance of expressed miRNA isoforms directly impacted the activation/deactivation of critical carcinogenesis pathways. Finally, we experimentally validated unique targeting for a shifted and edited miRNA isoform. Our findings outlined once more the importance of going beyond the well-established paradigm of one-mature-miRNA per miRNA arm to elucidate novel mechanisms related to cancer progression.

Pleural mesothelioma (PM) is a rare yet aggressive and heterogeneous cancer type with very poor survival rates. Due to its long latency period and nonspecific symptoms, the disease is usually detected at advanced stages, limiting available treatment options and leading to poor survival rates. So far, the disease can only be confirmed through invasive thoracoscopic biopsy. Moreover, the proposed circulating protein biomarkers lack sensitivity and specificity, highlighting the urgent need for novel approaches. In our previous work, we characterized the transcriptomic profile of extracellular vesicles secreted by PM cells and demonstrated their feasibility as a source of circulating biomarkers. To further investigate the role of circulating RNA in tumor progression and its potential use in non-invasive testing for PM, here we present a detailed characterization of RNA cargo carried by PM exosomes - a distinct subset of extracellular vesicles known to serve as key mediators of intercellular communication. By utilizing primary cell cultures established from tissue samples of 11 PM and 6 non-PM patients, followed by exosome isolation, and total RNA sequencing of RNA from isolated exosomes, matching cells, and tissues, we provide new evidence on exosomal RNA secretion, regulation of PM-exosome cargo genes, and their potential functions in recipient cells. We show that PM-exosomal cargo is enriched in genes associated with proliferation, whose key transcriptional factors are SETDB1, FOXM1 and GATA2. We identified Pcbp2, Srsf1 and Srsf9, RNA-binding proteins, which may be involved in selective cargo sorting into PM-exosomes. Our analysis identified six secreted genes, including GAS5, AL031666.3, RSLD1D1, AC103740.2, ADAM10, and AC020892.1, whose exosomal expression was associated with patient survival, as promising biomarkers for patient diagnosis, stratification, and prognosis assessment. Finally, we identify potential target genes of candidate LncRNAs biomarkers and processes in which they are involved.

BackgroundMulti-analyte liquid biopsies represents an emerging opportunity for non-invasive cancer assessment. We developed ONCE (ONe Aliquot for Circulating Elements), a novel multi-analytes liquid biopsy approach for the isolation of extracellular vesicles (EVs) and cell-free DNA (cfDNA) from a single aliquot of blood. MethodsWe assessed ONCE performance to classify HER2-positive early-stage breast cancer (BrCa) patients by combining RNA and DNA signals on n=64 healthy donors (HD) and non-metastatic BrCa patients. Specifically, we investigated EVs-derived RNA (EV-RNA) and cfDNA by next-generation sequencing (NGS) and by digital droplet PCR (ddPCR). Additionally, we utilized imaging flow cytometry to evaluate EVs as potential carriers of the HER2 protein. ResultsWestern blot analysis and immunocapture assay revealed that EVs-enriched proteins were detected at similar levels among the HER2+ and HER2- subtypes. Sequencing of cfDNA and EV-RNA from HER2- and HER2+ patients demonstrated concordance with in situ molecular analyses of matched tissues. Combined analysis of the two circulating analytes by ddPCR showed increased sensitivity in ERBB2/HER2 detection compared to single nucleic acid components. Multi-analyte liquid biopsy prediction performance was comparable to tissue-based sequencing results from TCGA. Also, we observed HER2 protein on the surface of EVs isolated from the HER2+ BrCa plasma, thus corroborating the potential relevance of studying EVs as companion analyte to cfDNA. ConclusionsThis data confirms the relevance of combining cfDNA and EV-RNA analytes for cancer assessment and supports the ONCE approach as a valuable tool for multi-analytes liquid biopsies clinical implementation.

H19, a lnc-pri-miRNA that encodes miR-675, is dysregulated in numerous cancers. However, the specific mechanisms underlying H19 processing, particularly miR-675 formation, remain unclear. Our study reveals that H19 is highly expressed and m6A modified in a METTL3-dependent manner in glioblastoma (GBM) and glioma stem cells (GSCs). Silencing METTL3 reduced both H19 and miR-675 levels, whereas overexpressing METTL3 promoted miR-675 processing without affecting H19 levels. Further, miR-675 derived from exogenously expressed H19 was affected considerably more in METTL3 silenced glioma cells compared to H19 levels, suggesting differential requirements in the processing of m6A modified H19 transcript. We demonstrate that H19 interacts with m6A reader proteins, IGF2BP2 and HNRNPA2B1, and silencing either reduced H19 and miR-675 levels. However, a high level of miR-675 seen in METTL3 overexpressing cells is severely affected in HNRNPA2B1-silenced compared to IGF2BP2-silenced glioma cells. Interestingly, IGF2BP2 silencing more significantly affected H19 stability from exogenous H19 construct, while HNRNPA2B1 silencing severely impacted miR-675 processing. Site-directed mutagenesis confirmed the presence of two m6A sites in the first exon of H19, with site #1 facilitating HNRNPA2B1 interaction to promote miR-675 processing. In contrast, the IGF2BP2 interaction is promoted by site #2, resulting in enhanced H19 stability. H19-METTL3-HNRNPA2B1-miR675 axis inhibited Calneuron 1 (CALN1), a known target of miR-675, to promote glioma cell migration. Notably, a low CALN1/high H19 predicted a poor prognosis in GBM patients and was further exacerbated by a high METTL3 or HNRNPA2B1 but not IGF2BP2 transcript levels. Thus, we found that the H19 transcript is highly expressed in GBM and m6A modified, and the m6A reader proteins, IGF2BP2 and HNRNPA2B1, regulate the H19 processing differently to promote glioma cell migration.

Neuroblastoma is a neural crest-derived pediatric malignancy characterized by marked cellular heterogeneity and variable differentiation status. Undifferentiated tumors are associated with aggressive clinical behavior, treatment resistance and poor outcome, highlighting the need to identify molecular mechanisms that sustain tumor cell plasticity and prevent differentiation. Vaccinia-related kinase 1 (VRK1) is a serine/threonine kinase involved in cell-cycle progression, DNA-damage responses and transcriptional regulation, and has previously been associated with neuroblastoma progression. However, its role in the control of neuroblastoma differentiation remains unclear. Here, we investigated the relationship between VRK1 expression, tumor differentiation and stem-like properties in human neuroblastoma. Analysis of patient tumor datasets and tissue microarrays showed that VRK1 expression is enriched in undifferentiated neuroblastoma and stage 4 tumors, and inversely correlates with established differentiation markers, including DDC, NCAM1 and S100B. This association was maintained in MYCN-non-amplified tumors, indicating that the relationship between VRK1 and differentiation is not dependent on MYCN status. Single-cell transcriptomic analyses further demonstrated elevated VRK1 expression in developmentally immature neural crest progenitor and Schwann cell precursor-like populations. Induction of neuronal or mesenchymal differentiation consistently reduced VRK1 expression in neuroblastoma cell lines and patient-derived cells. Conversely, VRK1 silencing promoted differentiation-marker expression, reduced nestin and Ki67 expression, and produced sustained differentiation-associated changes in xenograft tumors. VRK1 was also enriched in tumorsphere cultures that select for undifferentiated stem-like neuroblastoma cells. VRK1 depletion impaired tumorsphere growth, reduced intratumoral proliferation and altered the balance between undifferentiated cells and differentiated progeny, supporting a role for VRK1 in self-renewal and maintenance of progenitor-like tumor cells. Mechanistically, VRK1 expression positively correlated with the core stemness transcription factor SOX2 in neuroblastoma tumor cells. VRK1 knockdown reduced nuclear SOX2 abundance, whereas VRK1 overexpression increased SOX2 protein levels. In addition, analysis of the VRK1 locus identified an active chromatin configuration and potential SOX2-binding sites, consistent with a regulatory relationship between these factors. Together, these findings identify VRK1 as a regulator of the undifferentiated, proliferative and stem-like state in neuroblastoma. The VRK1-SOX2 axis may contribute to stabilizing tumor-cell immaturity and represents a potential target for differentiation based therapeutic strategies in high-risk neuroblastoma.

Cell-free DNA (cfDNA) methylation is a valuable biomarker in various cancers including colorectal cancer (CRC), but marker for both early diagnosis and prognostic prediction remain a critical unmet need. Here, we report the development of a 27-DMR (differentially methylated regions) plasma panel with dual diagnostic and prognostic functions. We first identified CRC-specific methylation features from 119 tissue samples and 161 plasma samples. Machine learning algorithms were then applied to develop diagnosis and prognosis models using the plasma samples in training cohort. In the tissue external validation cohort (GSE48684), the cfDNA methylation diagnosis model conducted with the panel, achieved an area under the curve (AUC) of 0.983, and for the plasma cfDNA model in the external validation cohort, the sensitivities for NAA, AA and CRC 0 - II are 48.4%, 52.2% and 66.7% respectively, with a specificity of 88%. Beyond its diagnostic capabilities, the methylation panel was also a powerful predictor of distant metastasis (AUC = 0.955) and patient prognosis (AUC = 0.867). Using normal samples as control, the changes in methylation score in both tissue and plasma were consistent across different lesions, although the degree of alterations varied with severity. The methylation scores vary between paired tissue and blood samples, suggesting distinct mechanisms of migration from tumor tissue to blood for the 27 DMRs. Together, our cfDNA methylation models based on 27 DMRs can identify different stages of CRC and predict metastasis and prognosis, ultimately enabling early intervention and risk stratification for CRC patients.

The role of red blood cells (RBCs) in tumorigenesis is poorly understood. We previously identified RBC-microRNAs with aberrations linked to lung cancer, including miR-93-5p. Here we find that miR-93-5p levels are elevated in RBC-derived exosomes among lung cancer patients and are associated with their shorter survivals. RBC-derived miR-93-5p transfers to cancer cells primarily through the exosomal pathway. The transferred RBC-miR-93-5p can target PTEN in cancer cells, and hence increase cell proliferation, invasion, and migration. RBC-derived miR-93-5p accelerates, whereas targeting miR-93-5p diminishes tumor growth in xenograft models. These findings reveal a novel biological function of RBCs in tumorigenesis, where they facilitate cancer progression by transferring the oncomiR via exosomes, thereby offering new diagnostic and treatment strategies for lung cancer.

Melanoma being one of the most common and deadliest skin cancers, has been rising since the past decade. Patients at advanced stages of the disease have very poor prognoses, as opposed to at the earlier stages. Nowadays the standard-of-care of advanced melanoma is resection followed by immune checkpoint inhibition based immunotherapy. However, a substantial proportion of patients either do not respond or develop resistances. This underscores a need for novel approaches and therapeutic targets as well as a better understanding of the mechanisms of melanoma pathogenesis. Long non-coding RNAs (lncRNAs) comprise a poorly characterized class of functional players and promising targets in promoting malignancy. Certain lncRNAs have been identified to play integral roles in melanoma progression and drug resistances, however systematic screens to uncover novel functional lncRNAs are scarce. Here, we profile differentially expressed lncRNAs in patient derived short-term metastatic cultures and BRAF-MEK-inhibition resistant cells. We conduct a focused growth-related CRISPR-inhibition screen of overexpressed lncRNAs, validate and functionally characterize lncRNA hits with respect to cellular growth, invasive capacities and apoptosis in vitro as well as the transcriptomic impact of our lead candidate the novel lncRNA XLOC_030781. In sum, we extend the current knowledge of ncRNAs and their potential relevance on melanoma. SignificancePreviously considered as transcriptional noise, lncRNAs have emerged as novel players in regulating many cellular aspects in health and disease including melanoma. However, the number and as well as the extent of functional significance of most lncRNAs remains elusive. We provide a comprehensive strategy to identify functionally relevant lncRNAs in melanoma by combining expression profiling with CRISPR-inhibition growths screens lowering the experimental effort. We also provide a larger resource of differentially expressed lncRNAs with potential implications in melanoma growth and invasion. Our results broaden the characterized of lncRNAs as potential targets for future therapeutic applications.

Recent studies have shown that the cell surface undergoes post-transcriptional modification by N-linked glycosylation. However, the question of whether RNA can be glycosylated by O-glycans remains to be explored. The presence of O-glycosylation in cells is indirectly revealed by the presence of O-glycans on RNAs following treatment with O-glycoproteases. To identify RNA O-glycosylation, we have developed a chemoenzymatic method for capturing and enriching O-glycosylated RNA (O-glycoRNA) using covalent immobilization on a solid support. GalNAcEXO selectively releases Tn-containing O-glycosylated RNAs (TnORNA). Using this method and SPCgRNA, we compared the expression of O-glycoRNAs and N-glycoRNAs in pancreatic cancer cell lines and tissues. We found that glycosylated miR-103a-3p, miR-122-5p, and miR-4492 regulate pancreatic cancer cell growth and proliferation through the PI3K-Akt pathway. In vitro assays and PDAC tissue analysis confirmed the potential regulatory roles of Tn-O-glycosylated miRNAs in pancreatic tumor growth and metastasis. Furthermore, a significant number (131) of miRNAs carrying both N- and Tn-O-glycosylation were identified, indicating the co-occurrence of N-linked and O-linked glycosylation on small RNAs. We have also developed PONglyRNA, an online bioinformatic tool for the site-specific prediction of RNA glycosylation. PONglyRNA identifies glycosylation motifs based on RNA sequence and has been validated using our glycoRNA data. In conclusion, this study establishes robust experimental and computational tools for identifying O-linked glycoRNAs. Additionally, it uncovers the novel role of glycosylation in PDAC development and progression through altered glycosylation of oncogenic miRNAs. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=195 HEIGHT=200 SRC="FIGDIR/small/599663v1_ufig1.gif" ALT="Figure 1"> View larger version (72K): org.highwire.dtl.DTLVardef@199511corg.highwire.dtl.DTLVardef@9c3338org.highwire.dtl.DTLVardef@e6d315org.highwire.dtl.DTLVardef@2c1fc1_HPS_FORMAT_FIGEXP M_FIG C_FIG

BackgroundThe mA modification is the most abundant RNA epigenetic mark in colorectal cancer (CRC). In this study, we focused on Hakai, a methyltransferase writer-associated protein whose molecular function within the complex and link to CRC immune regulation remain poorly characterized. MethodsWe performed RNA-seq to assess transcriptomic changes after Hakai silencing in CRC models and MeRIP-seq to profile methylation alterations. Validation was carried out by Western blot, flow cytometry, ELISA, and RT-qPCR. Protein interactions within the writer complex were analysed by co-immunoprecipitation, and changes in protein localization by cell fractionation assays. Peripheral blood from healthy donors and lamina propria mononuclear cells from CRC patients were incubated with supernatants from Hakai-silenced CRC cells to evaluate effects on immune responses. ResultsHakai silencing induced phenotypic changes in both monolayer and 3D CRC cultures, while its impact on the global transcriptome was limited. However, significant alterations in the methylation of immune response-related genes and reduced total mA levels were observed. Hakai interacted with the writer-associated protein VIRMA, and its silencing altered the subcellular localization of METTL3. Moreover, conditioned media from Hakai-silenced CRC cells modulated the expression of immune response markers in patient-derived gut immune cells. ConclusionsHakai acts as a component of the mA writer complex in CRC cells, influencing RNA methylation and the expression of immune-related genes. These findings suggest that Hakai silencing may enhance antitumour immune activity and represent a potential strategy to boost cancer immunity in colorectal cancer.

Lung cancer, the most lethal malignancy globally, urgently requires effective early detection methods. Current non-invasive approaches based on plasma cell-free DNA (cfDNA) fragmentomics are often constrained by limited sensitivity in early-stage patients due to low tumor DNA fraction. To overcome this, we introduce a novel computational feature--First-Order Transition Probability (FOTP)--to decode nucleotide sequential dependencies within cfDNA fragments. Through systematic analysis of 1,036 participants and low-pass whole-genome sequencing, we demonstrate that the first 10 bp at the 5' end harbor the most discriminative information for cancer detection. An SVM model leveraging FOTP achieved an AUC of 0.942, with 73.9% sensitivity for stage I and 81.8% for stage II lung cancer at 95% specificity, significantly outperforming existing fragmentomic features. Furthermore, the method generalized robustly across independent and multi-cancer validation sets, including HCC, CRC, and HNSCC, and exhibited potential for tissue-of-origin identification. These findings are supported by nucleotide frequency stability and entropy patterns beyond the initial 10 bp, reflecting underlying nuclease cleavage biases and chromatin features. This work establishes FOTP as a biologically interpretable and highly efficient feature for pan-cancer early detection, offering a scalable pathway toward population-wide screening programs.

A key limitation in cancer transcriptomics is the lack of accompanying genomic profiling such as whole-genome sequencing (WGS) or copy number alteration (CNA) data. Here we address this by showing that RNA-seq alone can be used to infer chromosomal aberrations and identify biologically meaningful patterns in lung cancer. Through a large-scale meta-analysis of publicly available RNA-seq datasets from non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), and matched controls, we reconstructed large scale CNA profiles and identified deletions in 3p, 9p, and 17p as the most frequent genomic events. Validation against paired WGS data confirmed a high degree of accuracy for RNA-seq-based inference. Our analyses revealed that while deletion-associated transcriptional heterogeneity exists, approximately 25% of differentially expressed genes were shared across all three deletion classes, indicating a conserved oncogenic program in lung cancer. Enrichment analysis linked these shared genes to pathways governing cell division, DNA replication, and extracellular matrix organization, while deletion-specific effects reflected disruption of tumor suppressor pathways, notably p53 signaling in 17p-deleted tumors, leading to deregulation of NOS2 and PLOD2. Integrating gene-level expression data, we identified both shared and deletion-specific biomarkers: TPX2 was consistently overexpressed across all deletion groups, while PTPRZ1 and CLDN9 were uniquely associated with del3p and del9p, respectively. Experimental validation in lung cancer cell lines confirmed these predictions, particularly the upregulation of CLDN9 in del9p carriers. By demonstrating that RNA-seq data can capture large-scale chromosomal events and reveal their transcriptional consequences, this study establishes an efficient framework for genomic inference and biomarker discovery, introducing CLDN9 as a novel, deletion-specific marker with potential prognostic and therapeutic value for 9p-deleted lung cancers.

Stem/progenitor-like cells are known drivers of tumor progression, chemoresistance, and relapse in Sonic-Hedgehog medulloblastoma (SHH-MB), yet the regulatory mechanisms that sustain these resilient cellular states remain incompletely defined. Here, we identify the RE1-silencing transcription factor (REST) as a key transcriptional regulator that preserves the progenitor compartment in SHH-MB through stabilization of the stemness factor SOX2. Mechanistically, REST activates AKT signaling, which in turn enhances SOX2 protein stability, revealing a REST-AKT-SOX2 axis that supports stem/progenitor identity and ongoing tumor maintenance. Beyond maintaining intrinsic stem-like programs, REST also orchestrates the extrinsic communication network of SHH-MB tumors. Single cell transcriptomic profiling and ligand-receptor interaction mapping highlight Midkine (MDK)-mediated signaling as one of the most upregulated intercellular communication routes in MB. We demonstrate that REST drives this signaling cascade through its control of SOX2. Perturbation of REST or SOX2 results in reduced MDK and its receptor, SDC2 expression, and chromatin immunoprecipitation assays show that SOX2 directly binds and regulates MDK/SDC2 expression, establishing and reinforcing a REST/SOX2 centered transcriptional mechanism that coordinates both progenitor maintenance and cell-cell communication in the malignant compartment. Together, these findings position REST as an integrator of intrinsic progenitor cell programs and extrinsic MDK-mediated signaling in SHH-MB. By linking stemness, communication and potential for therapeutic resistance, the REST-AKT-SOX2-MDK signaling axis emerges as a targetable vulnerability to suppress stem/progenitor driven tumor program in REST-driven SHH-MBs.

Gliomas are biologically heterogeneous brain tumors with marked differences in clinical behavior based on the IDH1 mutation status. While epigenetic dysregulation is well characterized, the contribution of RNA modifications, particularly N6-methyladenosine (m6A), remains underexplored. Using direct RNA nanopore sequencing of patient-derived gliomas, we generated the first isoform-resolved m6A maps across IDH1-mutant and wild-type tumors. IDH1-mutant gliomas exhibited globally elevated m6A methylation, along with increased expression of methyltransferases (METTL3, METTL14) and stabilizing readers (YTHDF3). In contrast, wild-type glioblastomas showed enhanced expression of m6A erasers (ALKBH5, FTO) and RNA decay factors (YTHDF2). These subtype-specific differences in m6A architecture impacted transcript stability, isoform usage, and gene expression. Isoform-level analyses revealed stronger prognostic associations than gene-level parameter, including for IGF2BP2-202, PUF60-202, and GLUL-203. Our study establishes m6A as a critical, subtype-specific layer of RNA regulation in glioma with clinical and therapeutic implications.

Metabolic reprogramming is a fundamental strategy that allows colorectal cancer (CRC) cells to endure microenvironmental constraints and sustain malignant progression. Here, we identify the transcription factor NF-Y as a master regulator of glutamine metabolism in CRC, with particular relevance to the aggressive CMS4 subtype. Loss of function experiments, integrated with metabolomic and transcriptomic analyses, reveal a critical role for NF-YA in regulating glutamine metabolism in CRC cells. Complementary gain of function studies pinpoint NF-YAl as the isoform specifically driving glutamine-centered rewiring. Mechanistically, NF-YAl directly binds the Glul promoter, inducing transcriptional upregulation of glutamine synthetase and increasing intracellular glutamine availability. This metabolic reprogramming enhances resistance to mechanical shear and oxidative stress under glutamine-limiting conditions, thereby promoting migratory and metastatic traits. Importantly, pharmacological inhibition of glutamine synthesis, but not uptake or downstream catabolism, selectively abrogates the survival and migratory advantage of NF-YAlhigh cells both in vitro and in vivo, highlighting a targetable vulnerability in aggressive CRC. Beyond CRC cell-autonomous advantage, NF-YAl-dependent glutamine biosynthesis reshapes the tumor microenvironment by promoting M2 macrophage polarization. Conditioned medium from NF-YAlhigh CRC cells is sufficient to induce human monocytes to adopt an M2-like phenotype. This effect is dependent on NF-YAlhigh tumor-derived glutamine, as inhibition of glutamine uptake by monocytes fully blocks their conversion to M2. In line with this, integrative analyses of patient-derived datasets underscore the predictive relevance of the NF-YAl-Glul-M2 axis in driving CRC aggressiveness. These findings define glutamine synthetase as a pivotal mediator of NF-YAl activity and a promising druggable metabolic Achilles heel in NF-YAlhigh CRC tumors.

ObjectiveRNA adenosine-to-inosine (A-to-I) editing, catalyzed by adenosine deaminases acting on RNA (ADARs), is a pervasive post-transcriptional mechanism that expands transcriptomic and proteomic diversity. However, the global landscape of RNA A-to-I editing, as well as its functional and clinical significance in esophageal squamous cell carcinoma (ESCC), remains largely unexplored. This study aimed to systematically characterize the RNA editome of ESCC and elucidate its biological and clinical significance. MethodsWhole-transcriptome sequencing was performed on 121 primary ESCC tumors, with or without lymph node metastasis, together with matched normal tissues, to construct a high-resolution RNA editome. ADAR1-regulated RNA editing events were identified, and their functional consequences were investigated using integrated transcriptomic, phosphoproteomic, and RNA immunoprecipitation sequencing (RIP-seq) analyses. Associations between CDK13 editing, cGAS-STING-interferon-stimulated gene (ISG) signaling, and patient survival were further evaluated. ResultsA total of 222,020 high-confidence RNA editing sites were identified, of which approximately 98% were A-to-I events, including 124,486 ESCC-specific edits predominantly enriched in introns, 3' untranslated regions, and non-coding RNAs, highlighting a pervasive post-transcriptional regulatory layer. RNA A-to-I editing was extensively remodeled and globally up-regulated in non-metastatic ESCC, whereas only minimal changes were observed during lymph node metastasis, indicating that RNA editing alterations predominantly occur during early tumorigenesis. CDK13 emerged as a recurrent ADAR1 target, with RNA editing inversely correlated with CDK13 expression. ADAR1-mediated CDK13 editing established a positive feedback loop associated with enhanced interferon-stimulated gene (ISG) signaling and poorer survival in non-metastatic ESCC. Mechanistically, partial attenuation of CDK13 induced chronic, tumor cell-intrinsic activation of the cGAS-STING-ISG pathway. Integrated multi-omics analyses further revealed that CDK13 regulates phosphorylation networks governing cytoskeleton organization, intracellular trafficking, RNA homeostasis, and immune signaling. ConclusionRNA A-to-I editing represents a dynamic regulatory mechanism driving early ESCC progression and remodeling tumor cell-intrinsic immune signaling. ADAR1-mediated editing of CDK13 provides a mechanistic link between RNA editing and cGAS-STING-ISG pathway activation, revealing potential therapeutic vulnerabilities and supporting its utility as an early prognostic biomarker in ESCC.

N6-methyladenosine (m6A) is the most prevalent internal mRNA modification, enriched in the CNS yet poorly characterized in glioma. Using long-read RNA sequencing, we mapped m6A in an in vitro glioma model following knockdown (KD) of the reader IGF2BP2, writer METTL3, and eraser ALKBH5, with naive glioma cells and astrocytes as controls. Glioma cells exhibited a two-fold reduction in global m6A, suggesting progressive loss from healthy to malignant states. Integrated analysis revealed that m6A mediated control of gene expression is influenced by modification topology (CDS:3'UTR), transcript biotype, and length. Regulator KD, particularly ALKBH5 induced redistribution of m6A toward 3'UTR with consequent gene upregulation. We also identified m6A-mediated isoform switching, with a higher usage of retained intron and nonsense-mediated decay isoforms. Structural and splicing alterations at the isoform level were identified unique to each KD condition indicating m6A driven aberrant alternative splicing. At the functional level, KD specific remodeling of oncogenic signaling was also observed. ALKBH5 KD suppressed MYC targets and pro-apoptotic signaling while METTL3 KD enhanced mTOR and PI3K-AKT signaling. Collectively, these results demonstrate that m6A mediated regulation in glioma is highly context-dependent, defining distinct clinically relevant phenotypes. This has implications for future biomarker discovery and development of targeted therapeutics.