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.

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.

SummaryA catch-all intronic guide RNA pair excises the KIAA1549--BRAF oncofusion across its major variants, with productive junction excision confirmed by gain-of-function PCR in patient-derived glioma cells. An allele-specific guide selectively disrupts BRAF V600E, in patient-derived pediatric low-grade glioma cells. Pediatric low-grade glioma (pLGG) is the most common brain tumor of childhood, accounting for 30--50% of all pediatric central nervous system malignancies1. The disease is almost universally driven by activating mutations in the BRAF serine/threonine kinase: a chromosomal tandem duplication generating the KIAA1549--BRAF oncofusion in approximately 70% of cases, or the BRAF V600E gain-of-function point mutation in approximately 15%2. Current targeted pharmacotherapies, including the RAF inhibitor tovorafenib, require continuous dosing, are not allele-specific, and carry risks of long-term toxicity in children. A one-time genomic intervention that permanently disables the oncogenic BRAF alteration while preserving wild-type BRAF signaling represents a compelling therapeutic alternative. In this study, we describe the design and experimental validation of allele-specific CRISPR guide RNAs targeting both the KIAA1549--BRAF oncofusion and the BRAF V600E point mutation. For the oncofusion, we developed a double-cut intronic excision strategy in which a guide RNA targeting KIAA1549 intron 14 is paired with a guide RNA targeting BRAF intron 11. Because the genomic breakpoints of all four major fusion variants (KB 16:9, 15:9, 16:11, and 15:11) fall within these introns, a single guide pair can address the full landscape of fusion heterogeneity in a single intervention. For BRAF V600E, we exploited a unique PAM sequence created by the pathogenic TBA transversion at codon 600, enabling allele-specific SpCas9 and AsCas12a guide designs that distinguish the mutant from the wild-type allele at single-nucleotide resolution. We screened guide RNA candidates by ribonucleoprotein (RNP) nucleofection in A375 human melanoma cells (BRAF V600E homozygous) and in patient-derived 3635 PXA glioma cells (BRAF V600E heterozygous). The top KIAA1549 intron 14 guide, K9_i14_A_Cas9, achieved 66% indel frequency in A375 cells. The top BRAF intron 11 guides, B_i11_A_Cas9 and B_i11_D_Cas9, achieved 84% and 85% indel frequency, respectively. For BRAF V600E, the best allele-specific SpCas9 guide achieved l57% editing in A375 cells and l74% editing in 3635 PXA patient-derived glioma cells. Dual-cut excision of the KIAA1549--BRAF junction was confirmed by a gain-of-function PCR assay designed to detect the excision junction amplicon ([~]191 bp) produced by NHEJ-mediated rejoining of the KIAA1549 intron 14 and BRAF intron 11 cut ends.

Head and neck squamous cell carcinoma (HNSCC) remains clinically challenging, with limited molecularly targeted options and a strong dependence on the tumor microenvironment. Cancer-associated fibroblasts (CAFs) are major stromal regulators that shape tumor progression, extracellular matrix remodeling, invasion, and therapeutic response. However, how CAF heterogeneity and plasticity translate into distinct tumor-promoting functions and targetable vulnerabilities remains insufficiently defined. Here, we integrated patient-matched primary CAFs and normal fibroblasts with 3D functional assays, tumor-stroma co-culture models, quantitative extracellular matrix analysis, whole-proteome profiling, and pharmacological perturbation. Primary fibroblast populations displayed marked interpatient heterogeneity and context-dependent plasticity in invasion, contractility, and responsiveness to tumor-derived signals, whereas enhanced fibronectin-rich matrix deposition and disorganization emerged as a conserved CAF-associated feature. Both normal fibroblasts and CAFs promoted HNSCC cell invasion in a population-dependent manner, whereas CAFs consistently induced less compact and more dispersed tumor nest architectures. Integrative functional analyses identified distinct CAF phenotypes characterized by either invasive and matrix-remodeling activity or high responsiveness to tumor-derived cues. Proteomic profiling revealed recurrent enrichment of adhesion, cytoskeletal, and extracellular matrix programs and guided the selection of pharmacological inhibitors aimed at modulating specific CAF-mediated pro-tumoral functions. Pharmacological targeting selectively altered these functions: CHI3L1 inhibition disrupted fibronectin matrix deposition, broad phosphodiesterase inhibition increased matrix alignment, and FZD7 inhibition consistently blocked tumor-induced CAF invasion across all tested populations. These findings define functionally distinct and pharmacologically targetable CAF programs in HNSCC and support stromal-directed interventions as a rational component of future combination treatment strategies.

Colorectal cancer (CRC) screening remains limited by patient adherence and sub-optimal sensitivity for early-stage disease. While liquid biopsy has revolutionized cancer diagnostics, cfDNA-based methods often struggle with early-stage detection due to low analyte levels. Here, we present a robust cell-free RNA (cfRNA) platform for the early detection of CRC. Using a retrospective cohort of 255 healthy controls and 250 CRC patients, we implemented an optimized workflow featuring a RUVg-based normalization strategy to remove platelet-driven transcriptomic noise. We identified differentially expressed genes enriched in key CRC-associated biological pathways, including inflammation, EMT, and metabolic dysregulation. An XGBoost classifier trained on these features achieved a mean AUC of 0.92 in cross-validation and 0.89 in a validation cohort, demonstrating 67% sensitivity at 90% specificity. Notably, our platform showed particular efficacy in identifying early stage cancer (stage I and II), achieving 73.7% sensitivity at 90% specificity. These findings suggest that cfRNA profiling offers a powerful, non-invasive orthogonal approach to CRC screening, capable of overcoming the sensitivity limitations of DNA-based assays in early-stage disease.

Alternative splicing coupled to nonsense-mediated mRNA decay (AS-NMD) evolved as a master regulator of gene expression. Dysregulated AS-NMD has been identified as the root of many human maladies, from developmental defects to deadly cancer. Poison exons (PEs) are highly conserved alternative exons that contain a premature termination codon and elicit AS-NMD when included in a transcript. Cancer cells often exploit the inclusion of PEs to downregulate tumor suppressors or the exclusion of PEs to upregulate oncoproteins. Therefore, PEs have drawn significant attention as a novel therapeutic avenue for cancer and other diseases. Here, we examine a therapeutic proof-of-concept for manipulating PE-mediated oncogenic AS-NMD using a CRISPR-based approach. Using paired guide RNA, we successfully deleted a PE of a tumor suppressor (EZH2) from the genome of SRSF2-mutated leukemia. This editing resulted in EZH2 mRNAs without a PE, escaped AS-NMD, and restored the protein expression. This subsequently reinstated H3K27 histone methylation and rescued defective chromatin regulation associated with impaired hematopoietic stem cell differentiation. Finally, we showed the preferential advantages of CRISPR over the antisense technology we recently developed targeting the PE of EZH2. Therefore, the CRISPR strategy shows compelling evidence as a therapeutic approach targeting PE in cancer and other human diseases.

Copy number variations (CNVs) can serve as important clinical biomarkers for tumor classification and stratification. However, the utility of these CNV biomarkers for intraoperative tumor assessment within the timeframe of neurosurgical procedures has remained elusive due to the protracted duration of conventional CNV characterization methods. Here, we introduce CNVisor, a statistical framework for reliable and robust CNV detection from long-read sequencing, even under ultra-low coverage. Applied to neurosurgical tumor specimens, the proposed method enabled genome-wide CNV profiling and identified clinically relevant CNVs using roughly 60,000 reads within 20 minutes of sequencing. Integrating CNVisor with methylation-based classifiers can further reduce turnaround time and increase the accuracy of glioma subtype stratification. Together, these findings establish real-time CNV profiling using ultra-low coverage nanopore sequencing as a feasible strategy for intraoperative, genomics-informed assessment of CNS tumors.

WNT11, a non-canonical WNT ligand, plays well-defined roles in development and tissue architecture; however, its function in cancer remains ambiguous. Here, we characterize WNT11 as a context-dependent suppressor of cancer stemness, invasion, and in vivo tumor formation in human epithelial cancer models. We show that WNT11 upregulation reduces the expression of stemness-promoting genes, suppresses epithelial-to-mesenchymal transition, and inhibits sphere formation and tumor growth. Conversely, downregulation of WNT11 enhances these aggressive malignant properties of cancer cells. Mechanistically, we found that the ability of WNT11 to inhibit RAC1 GTPase activation is essential for its regulation of invasion and self-renewal. In cells unresponsive to WNT11, the connectivity between WNT11 and RAC1 activity is disengaged. Direct manipulation of RAC1 activity in these cells recapitulates the phenotype and molecular signature of WNT11-responsive cells, establishing RAC1 as a critical effector of WNT11-mediated tumor suppression. Taken together, these findings identify the cellular context in which WNT11 suppresses RAC1 activation as a key determinant of its anti-tumor effects and provide a mechanistic framework for understanding the diverse, and sometimes opposing, roles of WNT11 reported in cancer.

Ewing Sarcoma (ES) is an aggressive neoplasm arising in bones and soft tissues driven by the oncogenic fusion EWSR1::FLI1. Through epigenetic deregulation, EWSR1::FLI1 generates de novo super-enhancers that control the expression of key genes for tumor cell maintenance. By an integrative in silico analysis, we identified the subunit of the Mediator complex MED13L and RERE, a member of the atrophin family of arginine-glutamic acid dipeptide repeat-containing proteins, as genes regulated by EWSR1::FLI1-bound super-enhancers. We confirmed that EWSR1::FLI1 regulates MED13L and RERE expression in ES cell lines and showed that these proteins are highly expressed in Ewing primary tumors. Besides the well-established role of the Mediator complex in transcriptional regulation given its association with the RNA polymerase II, in ES cells the DNA binding sites of MED13L overlap with those of RERE and EWSR1::FLI1 in genes that control protein translation and alternative splicing (AS). Accordingly, the expression of various spliceosome components is co-regulated by MED13L, RERE and the oncogene, leading to AS in ES cells. We identified RBM39, a splicing factor downregulated after MED13L and RERE depletion, as a direct transcriptional target of EWSR1::FLI1. Consistently, in vitro viability experiments using indisulam, which induces selective DCAF15-dependent proteosome degradation of RBM39, demonstrate ES cells highly and specifically sensitive to RBM39 inhibition. In vivo experiments with mice xenografted with ES cells show complete tumor regression with indisulam, highlighting the potential of this approach as a novel and promising therapeutic strategy for Ewing sarcoma. STATEMENT OF SIGNIFICANCEEwing sarcoma (ES) is characterized by FET::ETS oncoproteins that act as pioneer transcription factors. Here, we identified two genes controlled by EWSR1::FLI1-bound super-enhancers, MED13L and RERE, and characterized the mechanism by which these proteins cooperate with the oncogene to regulate RNA metabolism and ribosomal processes in ES cells. These findings have led to the identification of the splicing factor RBM39 as a vulnerability in ES, as supported by the extraordinary sensitivity of these tumors to monotherapy with RBM39 degrader indisulam.

This study proposes a novel therapeutic strategy to suppress cancer growth by modulating the MDM2-p53 axis via Alternative Polyadenylation (APA). MDM2 normally promotes tumorigenesis by ubiquitinating and degrading the tumor suppressor p53. In cancer cells, preferential use of proximal polyadenylation signals (PAS) results in shortened 3'UTRs, allowing oncogenic transcripts like MDM2 to evade nuclear sequestration mediated by Inverted Alu (IRAlu) double-stranded RNA structures. We hypothesized that forcing distal PAS usage would elongate the MDM2 mRNA, promoting its nuclear retention and reducing protein translation, thereby restoring p53 activity. Using CRISPR-Cas9, we targeted and deleted the most frequent proximal PAS in the MDM2 3'UTR of A549 cells. Successful genome editing was confirmed via PCR. As expected, Western blot analysis showed a significant reduction in MDM2 expression in PAS-edited cells. However, experimental outcomes contradicted our initial hypothesis: edited cells exhibited higher viability under doxorubicin treatment compared to wild-type cells. Furthermore, despite decreased MDM2 levels, a concurrent reduction in phosphorylated p53 (p-p53) was observed. These unexpected results suggest that MDM2 3'UTR elongation may trigger a non-canonical regulatory mechanism that bypasses the traditional MDM2-p53 interaction. This study highlights the complexity of post-transcriptional regulation and suggests that APA-mediated gene modulation can induce unforeseen compensatory survival pathways in cancer cells, necessitating further investigation into the broader functional landscape of elongated 3'UTRs.

Despite significant advancements in microsurgical techniques in recent years, the treatment and prognosis of craniopharyngiomas remain unsatisfactory. As a central nervous system tumor located adjacent to important brain structures such as the hypothalamus-pituitary axis and accompanied by a highly inflammatory microenvironment, the tumor heterogeneity and tumor microenvironment characteristics of papillary craniopharyngiomas (PCPs) remain unclear. In this study, we integrated multimodal single-cell and spatial profiling from PCP tissue and peripheral blood mononuclear cells (PBMCs) to elucidate the tumor heterogeneity and microenvironment characteristics of PCP. Our single-cell and spatial analyses defined four specific tumor cell states in PCP, representing specific transcriptional regulatory programs and spatial heterogeneity characteristics during tumor progression. By constructing a spatial niche composed of tumor, immune, and stromal cells, we analyzed the cellular and spatial ecosystem of PCP at multiple levels to further assess the communication relationships between different tumor cell states and microenvironment cells. This study established a multidimensional molecular atlas of PCP from the perspectives of cell state, spatial structure, and microenvironment interactions, providing a foundation for understanding its biological behavior and exploring new intervention strategies.

Primary tumor biopsy in retinoblastoma carries an unacceptable risk of extraocular dissemination. As a result, children treated with eye-sparing approaches currently lack access to tumor-derived genomic information at diagnosis, limiting accurate risk stratification, preventing subtype-guided therapy, and obscuring insight into tumor evolution during conservative treatment. Aqueous humor (AH) liquid biopsy has emerged as a promising window into circulating tumor DNA (ctDNA) from eyes managed conservatively, yet its ability to comprehensively capture the genomic and epigenomic landscape of retinoblastoma and to deliver clinically actionable molecular stratification has not been rigorously evaluated. We analyzed 18 matched AH-tumor pairs using genome-wide methylation profiling, copy-number analysis, and targeted sequencing. AH samples consistently contained high ctDNA fractions (median 0.65), enabling robust detection of single-nucleotide variants, canonical copy-number alterations, and methylation signatures defining established retinoblastoma subtypes. Importantly, promoter methylation patterns associated with RB1 inactivation and optic nerve invasion were confidently detected in AH, highlighting that liquid biopsy enables functional interrogation of disease-relevant genes and pathways. To enable biopsy-independent molecular classification, we developed a methylation-based machine learning classifier trained on combined AH and tumor datasets (n=114). The classifier demonstrated exceptional performance, with AUCs of 0.96-1.00 in cross-validation and 0.97-1.00 in independent validation across 63 additional retinoblastoma cases. Together, these findings position AH liquid biopsy as powerful, minimally invasive platform for comprehensive molecular profiling in retinoblastoma. This work establishes the first clinically viable non-invasive molecular stratification tool for the disease, enabling pretreatment risk assessment and paving the way for next-generation precision diagnostics in eye-preserving care.

Abstract Background: Intraductal papillary mucinous neoplasms (IPMNs) are recognized as precursor lesions to pancreatic ductal adenocarcinoma (PDAC). However, the molecular programs underlying progression from low-grade dysplasia to advanced disease remain incompletely characterized. Herein, we performed an integrated plasma and tissue-proteomic analyses coupled with spatial and single-cell transcriptomics to identify biologically coherent remodeling programs reflected in circulation that distinguish IPMN by dysplasia grade and invasive disease. Methods: Using the O-link proximity extension assay platform, a panel of 1,104 proteins were quantified in plasma samples collected from patients with low-grade (LG) IPMN (n=30), high-grade (HG) IPMN with or without associated PDAC (IPMN/PDAC; n=40) and PDAC without IPMN (n=8). Predictive performance of individual biomarkers were assessed; likelihood ratio testing was performed to identify protein biomarkers that were complementarity with CA19-9 for risk of malignancy of IPMN. Findings were intersected with available spatial (N= 13) and single-cell (N= 6) transcriptomic datasets of IPMN tissues as well as mass spectrometry-based proteomic profiles of an independent set of resected human IPMN tissues (N= 9). Results: A total of 28, 43, and 35 circulating proteins were found to be differential in HG, IPMN/PDAC, and HG + IPMN/PDAC cases compared to LG IPMN. Among differential proteins were known PDAC-associated markers CEACAM5, CTRC, and REG3A as well as several biomarkers reflecting cytoskeletal and extracellular matrix remodeling and inflammatory processes. Focusing on cytoskeletal and ECM-related proteins and using likelihood ratio testing, an OR rule considering CA19-9, BGN, and ITGB1BP1 achieved overall sensitivity of 48.7% for HG + IPMN/PDAC, including 38.1% sensitivity for HG IPMN, at an overall specificity of 90%, which was improved compared to that of CA19-9 alone (overall sensitivity of 28.2%; McNemar Exact test 1-sided p-value: 0.011). Integrated proteomic and spatial transcriptomic datasets of IPMN tissues revealed coordinated alterations cytoskeletal and ECM remodeling and elevated matrix stiffness as prominent features associated with IPMN/PDAC, which paralleled concordant increases in BGN and ITGB1BP1. Cell-type of origin analyses based on spatial and single-cell data further revealed fibroblasts and myeloid cells as primary contributors to expression levels of BGN whereas ITGB1BP1 was primarily expressed in neoplastic epithelium. Conclusion: Advanced IPMN dysplasia and invasive disease are characterized by coordinated tissue remodeling programs that are systemically reflected in circulating proteomic profiles. Blood-based biomarkers identified through our study, such as BGN and ITB1BP1, have potential to improve upon CA19-9 for risk stratification of IPMN to better guide clinical management.

The spatial architecture of the tumor microenvironment (TME) is pivotal in the progression of colorectal cancer (CRC) liver metastasis. By applying high-plex spatial multi-omic mapping and neighborhood analysis to a discovery cohort of colorectal cancer primary tumor (PT) and paired liver metastases (LM), we identified a specialized vimentin-high macrophages-endothelial cells niche that orchestrates cancer-associated fibroblast (CAF) phenotypes. Mechanistically, in primary tumors, vimentin-high macrophages secrete INHBA to activate the ACVR2/TGF-{beta} axis in endothelial cells, driving CAFs toward a myCAF phenotype. Conversely, in liver metastases, these macrophages secrete CXCL9 to trigger the PI3K-Akt/NF-[kcy]B/CXCL12 cascade in endothelial cells, directing CAFs toward an iCAF state. Clinically, high niche activity predicts poor survival. Divergent endothelial signaling in primary versus metastatic lesions exposes site-specific stromal vulnerabilities for therapeutic targeting, with architectural features discernible from routine histopathology. These findings reveal a site-specific regulatory mechanism of the macrophage-endothelial niche, offering a novel and clinically significant biomarker for CRC prognosis.

Circular RNAs (circRNAs) are ubiquitous in eukaryotes; dysregulated circRNA expression is linked to diseases, including lung cancer. In contrast to canonical circRNAs arising from exon-intron boundaries, noncanonical circRNAs originating within exonic, intronic, and intergenic regions have typically been dismissed as transcriptional noise or technical artifacts. To explore circRNA diversity and appreciate their functions, we developed an algorithm to identify both canonical and noncanonical circRNAs without relying on genome annotation, enabling the identification of circRNAs of all types and in newly sequenced or poorly annotated species. Results from lung cancer cells revealed that noncanonical circRNAs constituted over two-thirds of the circRNA population and were expressed more abundantly than canonical circRNAs, and genes with fewer and shorter exons were hotspots for noncanonical circRNA and circRNA isoform production. Further analyses showed that many noncanonical circRNAs were indeed endogenous circRNAs transcribed within cells rather than experimental artifacts, were potentially translated into proteins or peptides, and were conserved across species. Moreover, we validated 65 noncanonical circRNAs in NCI-H23 cells using multiple bioassays and demonstrated that both exonic and intergenic noncanonical circRNAs influenced cell viability. CircRNA profiles in tumor and tumor-adjacent tissues of lung cancer patients revealed tissue-specific expression and differentially expressed canonical and noncanonical circRNAs from cognate genes involved in cancer-related pathways, indicating their potential clinical relevance. This study confirmed the authenticity of noncanonical circRNAs and provided the first experimental evidence that noncanonical circRNAs influence cancer cell phenotypes. These findings broaden our understanding of circRNA biology, highlighting their widespread genomic distribution, diverse functions, and potential clinical relevance.

The human genome is pervasively transcribed into protein-coding and regulatory non-coding RNAs whose functions are coordinated within higher-order nuclear architectures. However, direct mapping of RNA-RNA and DNA-DNA interaction networks in complex human tissues at single-cell resolution has remained a major challenge. Here, we present SCIENCE-seq, a multimodal single-cell interactomics platform enabling simultaneous detection of RNA-RNA interactions and chromatin DNA-DNA contacts within individual cells. Applied to primary glioma specimens, SCIENCE-seq reveals cancer-specific interactions organized by lncRNAs and centered on key oncogenic drivers, including EGFR, hTERT, SOX2, CDK6, CDC42, CD47, and HOX loci. These datasets uncover previously unrecognized molecular relationships between premature lncRNAs and pre-mRNAs that regulate transcription, alternative splicing, and polyadenylation. Notably, we identify a glioma-specific trans-chromosomal HOX hub driven by five interacting lncRNAs. Targeting specific RNA and DNA interactions using steric antisense oligonucleotides (ASOs) or CRISPRi selectively suppresses oncogenic programs in malignant cells while sparing normal tissue, establishing chromatin interactomes as actionable therapeutic targets.

Lung cancer remains the leading cause of cancer-related mortality worldwide, with cigarette smoking (CS) representing its primary risk factor. In addition to promoting tumorigenesis, chronic CS exposure contributes to chemotherapy resistance, although the underlying mechanisms remain poorly understood. Here, we established a long-term CS exposure model by repeatedly treating Lewis lung carcinoma (LLC) cells with cigarette smoke extract (CSE). After 4 months of exposure, CSE-treated cells exhibited enhanced proliferation, migration, and resistance to chemotherapy-induced cell death. Mechanistically, chronic CSE exposure suppressed receptor-interacting protein kinase 3 (RIPK3) expression by upregulating the epigenetic regulator enhancer of zeste homolog 2 (EZH2), which promoted repressive histone methylation at the RIPK3 promoter. Loss of RIPK3 impaired chemotherapy-induced cell death primarily by inhibiting ferroptosis rather than necroptosis. Importantly, genetic depletion or pharmacological inhibition of EZH2 restored RIPK3 expression and sensitized lung cancer cells to gemcitabine treatment both in vitro and in vivo. Furthermore, analysis of human lung cancer datasets revealed an inverse correlation between EZH2 and RIPK3 expression, with RIPK3 levels progressively decreasing with smoking history. Collectively, these findings identify the EZH2/RIPK3 axis as a critical mediator of smoking-associated chemoresistance and uncover a previously unrecognized role for RIPK3 in ferroptosis regulation. Targeting EZH2-mediated RIPK3 suppression may represent a promising therapeutic strategy to overcome chemoresistance in lung cancer patients with a history of smoking.

Despite continuous progress in diagnosis and therapy, breast carcinoma (BC) remains a major health problem. Triple-negative (Estrogen Receptor-/Progesterone Receptor-/HER2-) breast cancer (TNBC) is the most aggressive subtype due to its high metastatic potential and resistance to chemotherapy. The Y-box binding protein 1 (YB-1) transcription factor, a protein present in both cytoplasm and nucleus, is a driver of TNBC malignancy as it stimulates its cancer stem cell phenotype and disrupts cell cycle progression. Here, we hypothesized that YB-1-containing sEVs deliver YB-1 to the nuclear compartment of recipient cancer cells and play a major role in the activation of the metastatic process. We found a selective enrichment of YB-1 in sEVs from MDA and 4T1 cells, with [~]65% and 50% of all sEVs positive for YB-1 by d-STORM. Administration of sEVs from wild-type MDA and 4T1 to their YB-1 knockout counterparts resulted in nuclear translocation of sEV-associated YB-1 and increased tumorsphere formation. Pharmacological blockade of the nuclear transport machinery based on the inhibition of the formation of the "VOR" complex (VAP-A-ORP3-Rab7) by PRR851 impaired both nuclear translocation and the YB-1-induced increase in tumorsphere formation. YB-1 phosphorylation at S102 was required for nuclear localization. In fact, loss of YB-1 phosphorylation inhibited tumorsphere growth and stemness of cancer cells and YB-1-positive sEVs restored the oncogenic behavior of cancer cells expressing phospho-mutant YB-1. Moreover, PRR851 inhibited the nuclear translocation of the phosphorylated form of YB-1 and the oncogenic behavior of the TNBC cells. These data support the conclusion that the nuclear translocation of sEV-associated phosphorylated YB-1 is an important factor in the malignant behavior of TNBC and a potential therapeutic target.

Comprehensive analyses of whole-genome and exome sequencing data from high-risk neuroblastoma tumors have revealed relatively few recurrent, clinically actionable protein-coding driver mutations at initial diagnosis. This observation suggests that noncoding genetic variation, which can alter regulatory sequences like promoters, enhancers and insulators and influence gene expression, may play a critical role in neuroblastoma tumorigenesis. By integrating allele-specific expression (ASE) with somatic mutation profiles from two independent neuroblastoma patient cohorts, we identified a significant and reproducible enrichment of noncoding single-nucleotide variants (SNVs) within regulatory regions of neuroblastoma-specific ASE (NB-ASE) genes. Notably, 63% of these variants disrupted transcription factor binding sites (TFBSs), with FOXJ2 being the most frequently affected transcription factor (TF) across both cohorts. Supporting a functional link between FOXJ2 TFBS SNVs and gene expression dysregulation, NB-ASE genes harboring these variants were significantly enriched among FOXJ2 co-expression partners. These findings nominate FOXJ2 dysregulation via TFBS mutations as a potentially crucial molecular mechanism contributing to aberrant gene expression profiles of neuroblastoma. To prioritize high-impact regulatory mutations associated with NB-ASE genes, we also performed extensive deep learning-based functional predictions and identified 297 TFBS mutations predicted to significantly alter chromatin state. Among these were variants predicted to deactivate enhancers regulating the tumor suppressor genes CASZ1 and PRDM11, both detected in tumors lacking copy-number alteration at the locus, suggesting an alternative, copy number-independent mechanism of downregulation. Collectively, our findings demonstrate that integrating ASE with somatic mutation profiles is a powerful strategy for detecting and interpreting regulatory variations in cancer genomes.

MYCN amplification drives replication stress in high-risk neuroblastoma, yet how MYCN-amplified tumour cells tolerate this stress to sustain proliferation remains poorly understood. Here we show that FBXL12, an SCF ubiquitin ligase substrate receptor that targets the Fanconi anaemia protein FANCD2 for degradation at replication forks, as well as the broader Fanconi anaemia and replication stress transcriptional program are elevated in high-risk and MYCN-amplified neuroblastoma. High FBXL12 expression independently predicts poor survival across neuroblastoma patient cohorts. FBXL12 loss stabilizes FANCD2 on chromatin, elevates ATR-dependent replication stress signalling and DNA damage during S phase, and impairs proliferation of MYCN-amplified neuroblastoma cells in vitro and in vivo. Mechanistically, MYCN directly engages the FBXL12-FANCD2 complex and antagonises FBXL12-mediated degradation of FANCD2 at replication forks, revealing that the oncogenic driver of replication stress also actively preserves the chromatin-bound FANCD2 pool required to tolerate it. Beyond S phase, FBXL12 loss disrupts FANCD2-dependent mitotic DNA synthesis and transmits unresolved replication intermediates into daughter cells. FBXL12-deficient cells consequently show transcriptional activation of MYC target gene, ATR, and mTOR signalling programs, and this pathway-concordant state confers differential sensitivity to ATR, and mTOR-targeting compounds, nominating candidate therapeutic strategies for this disease subset. Together, these findings define a MYCN-FBXL12-FANCD2 axis as a clinically relevant vulnerability in high-risk neuroblastoma.