Glioblastoma (GBM) is the most common and deadly primary brain tumor in adults. Understanding GBM pathobiology and discovering novel therapeutic targets are critical to finding efficient treatments. Upregulation of the lysosomal cysteine carboxypeptidase cathepsin X has been linked to immune dysfunction and neurodegenerative diseases, but its role in cancer and particularly in GBM progression in patients is unknown. In this study, cathepsin X expression and activity were found to be upregulated in human GBM tissues compared to low-grade gliomas and nontumor brain tissues. Cathepsin X was localized in GBM cells as well as in tumor-associated macrophages and microglia. Subsequently, potent irreversible (AMS36) and reversible (Z7) selective cathepsin X inhibitors were tested in vitro. Selective cathepsin X inhibitors decreased the viability of patient-derived GBM cells as well as macrophages and microglia that were cultured in conditioned media of GBM cells. We next examined the expression pattern of neuron-specific enzyme γ-enolase, which is the target of cathepsin X. We found that there was a correlation between high proteolytic activity of cathepsin X and C-terminal cleavage of γ-enolase and that cathepsin X and γ-enolase were colocalized in GBM tissues, preferentially in GBM-associated macrophages and microglia. Taken together, our results on patient-derived material suggest that cathepsin X is involved in GBM progression and is a potential target for therapeutic approaches against GBM.

Glioblastoma (GB) is an aggressive primary brain cancer with poor patient prognosis. Natural killer (NK) cells can recognise and eliminate a range of malignant cells, including GB stem cells, which drive GB recurrence. NK cell-based immunotherapy has emerged as a promising approach for GB treatment, but a better understanding of the complex crosstalk between GB and NK cells is needed, particularly within the immunosuppressive GB tumour microenvironment. In this study, we established a reproducible protocol for the production and dynamic culture of uniformly sized GB spheroids using the Celvivo Clinostar system. Our spheroids recapitulated the heterogeneous structure of GB and expressed ligands for NK cell receptors at levels distinct from those observed in corresponding GB cell lines in standard culture, implicating altered sensitivity of GB cells to NK cells in dynamic 3D cultures. GB-NK cell crosstalk was GB cell type dependent and the ability of NK cells to infiltrate GB did not necessarily correlate with their cytotoxicity against GB cells. Spheroids derived from differentiated GB cells secreted higher levels of immunomodulatory cytokines compared to spheroids from GB stem-like cells, and a prominent increase in the secretion of immune-attracting factors was observed in their co-cultures with NK cells. Finally, the CD155-DNAM1/TIGIT axis was indicated as an important regulator of NK cell cytotoxicity against GB stem-like cells. Collectively, our results highlight important factors in GB-NK cell communication and provide a groundwork for further targeted research as well as therapeutic evaluation of NK cell-based approaches in the established dynamic 3D cultures.

Glioblastoma (GB) is an aggressive primary brain cancer with poor patient prognosis. Natural killer (NK) cells can recognise and eliminate a range of malig

Glioblastoma (GBM) remains one of the most lethal human malignancies, yet extraneural metastases are exceptionally rare and poorly understood. Standard treatment-surgical resection followed by chemoradiotherapy-offers only modest survival benefits, and therapeutic options for metastatic GBM are limited. Here, we describe a rare clinical case of metastatic GBM and provide comprehensive molecular characterization alongside a potential targeted treatment strategy. The tumor exhibited several molecular features associated with aggressive behavior, including alterations in the tumor suppressor genes NF1, TP53, PTEN, and RB1, a mesenchymal DNA‑methylation subclass, and activation of the MAPK signaling pathway. To functionally evaluate therapeutic vulnerabilities, we developed tumor models using patient‑derived GBM cells and their assembloids with cerebral organoids that recapitulate patient‑specific tumor biology and the human brain microenvironment. We identified the MEK inhibitor trametinib as a promising candidate capable of selectively reducing viability and invasion of highly aggressive, stem‑like GBM cells within our personalized patient-derived tumor avatars. This work highlights the proof-of-concept evidence that MEK pathway inhibition may represent a potential therapeutic vulnerability to counteract rapid tumor spread and improve responsiveness to temzolomide in this individual metastatic GBM case. Study underscores the need for continued research to advance targeted, multi‑modal therapeutic approaches for GBM.