NR3C1 promotes group 4 medulloblastoma invasion via activating VCAN

Approximately 30% of group 4 medulloblastomas (G4-MBs) present with metastasis at diagnosis, yet the molecular mechanisms remain unclear. To elucidate differences of genes' expression between primary tumors of metastatic (M+) and non-metastatic (M0) G4-MB, we performed multi-omics profiling, including RNA sequencing, proteomics, single-nucleus RNA sequencing (snRNA-seq), and spatial transcriptomics on tumor samples. Integrative analyses identified VCAN, a chondroitin sulfate proteoglycan, as the most significantly up-regulated gene in primary tumors of M+ G4-MB. High expression of this gene was correlated with poor patient prognosis. Functional assays demonstrated that VCAN promotes proliferation and invasion while inhibiting apoptosis. In addition, NR3C1 was predicted as the key activator of VCAN by Single-Cell Regulatory Network Inference and Clustering (SCENIC). High-definition spatial transcriptomics revealed that NR3C1 and VCAN are highly co-expressed within the same spatial domains. Multiplex immunofluorescence confirmed the co-localization, providing spatial evidence of their regulatory interaction. ChIP-qPCR subsequently confirmed direct binding of NR3C1 to the VCAN promoter. Knockdown of NR3C1 or VCAN suppressed invasion and proliferation and induced apoptosis of the tumor cells, which were partially reversed by VCAN overexpression. Together, these findings revealed that the NR3C1-VCAN axis played a pivotal role in the metastatic progression of G4-MB, highlighting a potential therapeutic target for high-risk patients.