Minxuan Sun

Background: Colorectal cancer (CRC) exhibits substantial metabolic and transcriptomic heterogeneity, but the relationship between sulphur-handling transcriptional programmes and consensus molecular subtypes (CMS) remains incompletely resolved. Methods: We analysed a predefined 14-gene sulphur-handling panel across The Cancer Genome Atlas colon and rectal adenocarcinoma cohorts (TCGA-COAD/READ) and six independent HG-U133 validation cohorts ( n = 1,337 tumours). Analytical workflows integrated differential expression comparing tumours with adjacent-normal mucosa, CMS association modelling, random-effects meta-analysis, adjustment for three orthogonal tumour-purity estimators (ESTIMATE, consensus purity estimates, and ABSOLUTE), reference-based single-cell deconvolution with independent cross-atlas verification, and direction-aware therapeutic triage. Results: Colorectal tumours demonstrated branch-specific transcriptional alterations, marked by coordinated downregulation of sulphur oxidation and clearance genes ( SQOR , ETHE1 , TST ) and of the cysteine-catabolism genes CDO1 and CTH , and selective upregulation of SLC7A11 and AHCY , whereas CBS was not significantly altered. The composite programme score differed across CMS subtypes and was consistently lower in mesenchymal CMS4 tumours than in non-CMS4 tumours across all discovery and validation series. This association remained statistically detectable after adjustment for three global tumour-purity metrics. The programme score showed no statistically detectable independent association with overall, recurrence-free, or disease-free survival. Single-cell deconvolution supported expression across epithelial, stromal, and immune compartments. Direction-aware therapeutic triage prioritised SLC7A11/xCT inhibition as an exploratory candidate for preclinical testing. Conclusion: Sulphur-handling transcriptional architecture is reproducibly linked to CRC molecular taxonomy and is not fully explained by measured tumour purity variation, providing a computational framework for future functional and compartment-resolved investigation of sulphur metabolism in stratified CRC populations.

Background: Although nucleophosmin (NPM1) is a well-characterized oncogene in acute myeloid leukemia, much less is known about its role in solid tumor immunity. Here, we examined the function of NPM1 in regulating anti-tumor immunity within the tumor microenvironment. Methods: The proportion and functional changes of macrophages and T cells were detected by flow cytometry, the downstream regulatory genes of NPM1 were detected by RNA-seq, the binding ability of NPM1 and STAT3 was analyzed by Chip and luciferase assay. Results: NPM1 inhibition or genetic deficiency promoted tumor growth in MC38 colon cancer and LLC lung cancer mice models. Npm1 ^+/- mice exhibited enhanced infiltration and polarization of immunosuppressive M2-like tumor-associated macrophages (TAMs) and impaired CD8 ⁺ T cell function. Mechanistically, NPM1 bound to p-TAT3/STAT3 and promoted transcription of CCRL2, a key regulator of macrophage polarization. Overexpression of Npm1 in mice suppressed tumor growth, reduced M2 TAMs polarization, and enhanced CD8 ⁺ T cell-mediated anti-tumor immunity. Conclusion: Our findings revealed that NPM1 protects against tumor progression by regulating TAMs polarization and T cell function via the STAT3-CCRL2 axis.

While the RNA modification N⁶-methyladenosine (m⁶A) is known to influence immune cell function, its specific role in regulating macrophage migration and invasion remains poorly defined. This study aimed to elucidate the function and mechanism of the core m⁶A methyltransferase METTL3 in the migratory and invasive capacities of macrophages. A macrophage-specific METTL3-knockdown model was established. The functional effects of METTL3 deficiency were systematically evaluated using migration, invasion, phagocytosis, and polarization assays. Subsequent transcriptome sequencing (RNA-seq) and methylated RNA immunoprecipitation-quantitative PCR (MeRIP-qPCR) were employed to identify the key differentially expressed gene, lysyl oxidase-like 2 (LOXL2). This mechanistic link was ultimately confirmed through functional rescue experiments and reconstitution assays. METTL3 deficiency significantly increased the migratory and invasive capacities of macrophages but attenuated their phagocytic activity, promoting a shift toward an M2-like polarization state. Mechanistically, METTL3 knockdown reduced m⁶A modification at a specific site of LOXL2 mRNA, thereby decreasing its RNA stability and leading to decreased expression. Importantly, this phenotype was validated through functional inhibition assays. Reconstitution of LOXL2 in METTL3-deficient macrophages substantially reversed the enhanced migratory and invasive phenotypes. This study reveals a novel METTL3-m⁶A-LOXL2 signaling axis that posttranscriptionally fine-tunes macrophage migration and invasion by regulating gene expression. These findings provide a mechanistic explanation for the functional dynamics of macrophage migration and invasion and underscore that m⁶A modification is a key regulator of innate immune cell behavior.

Isocitrate dehydrogenase (IDH) mutations are associated with better prognosis and longer survival in gliomas. In contrast, multifocal glioma is a rare intracranial tumor, primarily affecting middle-aged and elderly individuals. While recurrence is common due to the complex tumor microenvironment, cellular heterogeneity, and clonal evolution, multifocal recurrence originating from an initially unifocal, low-grade glioma has been rarely reported. We present the case of a 36-year-old male initially diagnosed with oligodendroglioma, IDH-mutant and 1p/19q-codeleted, CNS WHO grade 3. After gross total resection and standard chemoradiotherapy, the patient developed multifocal recurrence after three years, with new lesions in the left temporal and frontal lobes. Histopathological analysis revealed divergent progression: the distal temporal lesion demonstrated glioblastoma-like features, whereas the in situ frontal recurrence retained characteristics of oligodendroglioma. To investigate the mechanism of multifocal tumor recurrence, we performed single-cell sequencing analysis on both foci, revealing distinct cellular compositions and hidden lineage relationships among malignant cells. We describe a rare case of multifocal glioma recurrence in a middle-aged adult, highlighting the cellular heterogeneity and lineage relationships between distinct tumor foci. This case contributes to the limited literature on multifocal glioma recurrence and provides a well-characterized specimen for investigating the molecular distinctions between IDH-mutant and IDH-wildtype gliomas.

Nucleophosmin 1 (NPM1) is commonly mutated in myelodysplastic syndrome (MDS) and acute myeloid leukemia. Concurrent inflammatory bowel diseases (IBD) and MDS are common, indicating a close relationship between IBD and MDS. Here we examined the function of NPM1 in IBD and colitis-associated colorectal cancer (CAC). NPM1 expression was reduced in patients with IBD. Npm1 ^+/− mice were more susceptible to acute colitis and experimentally induced CAC than littermate controls. Npm1 deficiency impaired the function of interleukin-22 (IL-22)-producing group three innate lymphoid cells (ILC3s). Mice lacking Npm1 in ILC3s exhibited decreased IL-22 production and accelerated development of colitis. NPM1 was important for mitochondrial biogenesis and metabolism by oxidative phosphorylation in ILC3s. Further experiments revealed that NPM1 cooperates with p65 to promote mitochondrial transcription factor A (TFAM) transcription in ILC3s. Overexpression of Npm1 in mice enhanced ILC3 function and reduced the severity of dextran sulfate sodium-induced colitis. Thus, our findings indicate that NPM1 in ILC3s protects against IBD by regulating mitochondrial metabolism through a p65-TFAM axis.