We performed transcriptome analysis of all known genes of peptidases also called proteases and their endogenous inhibitors in glioblastoma multiforme (GBM), which is one of the most aggressive and deadly types of brain cancers, where unbalanced proteolysis is associated with tumour progression. Publicly-available data sets and our own datasets were integrated and normalitzed using bioinformatics tools to reveal protease and protease inhibitor genes with deregulated expression in both malignant versus non-malignant tissues and cells. Of 311 protease genes identified to be differentially expressed in both GBM tissues and cells, 5 genes were highly overexpressed, among them was also lysosomal protease cathepsin K (CTSK). CTSK overexpression was validated using RT-qPCR in GBM tissues as well. Cathepsin K immunohistochemical staining and western blotting showed that only proteolytically inactive proforms of cathepsin k were overexpressed in GBM tissues and cells. In conclusion the presence of high levels of inactive pro-forms of cathepsin K in GBM tissues and cells indicate that in GBM the proteolytic/collagenolytic role is not its primary function but it plays rather a different yet unknown role.
Here we have investigated the potential use of human mesenchymal stem cells (MSC) for anticancer therapy of GBM, the most malignant brain tumour. We studied the mutual response of MSC and GBM cells in the indirect cultures in vitro at protein (cytokines) and transcription levels. we identified cytokines responsible for changed cocultured cells' phenotype, and revealed upregulated secretion of CCL2/MCP-1 cytokine from MSC. Other genes/proteins were identified for the first time to take part in MSC/GBM crosstalk. These results are useful for future gene targeting in cell-based anticancer therapy.
Despite improved treatment options, glioblastoma multiforme (GBM) remains the most aggressive brain tumour with the shoprtest survival. Arsenite is alreaedy being used in the treatment of acute promyelocytic leukaemia (APL), yet its effects on GBM have not been evaluated in detail. Using metabilic and cell viability assays, we demonstrated that long-zerm CatL silencing significantly increased arsenite cytotoxicity in U87 spheroids. Silenced CatL increased arsenite-mediated apoptosis in spheroids via elevated p53 expression, Bax/Bcl2 ratio and caspase 3/7 activity. The results have significant translational impact, since stable CatL silencing would enable the application of lower systemic doses of arsenite to achieve the desired cytotoxic effects on GBM in vivo.
In this study we have investigated the interaction of human mesenchymal stem cells (MSC) and tumor cells, fundamental for MSC' cellular treatment vectors' design. We demonstrated that in gliomas, the recruitment of MSC is driven by glioma-secreted factors. We showed that glioma cells as well as MSC differentially express connexins, by which they interact via gap-junctional coupling to form functional and structural sincytium, which is responsible for cells' phenotype change. The described phenomena provides new insight into the complexity of interactions between tumour cells and host MSCs.
This study is first to prove the prognostic value of Stefin A expression for GBM patients survival. We have previously demonstrated that the activity of cysteine cathepsins is elevated in invasive glioblastoma (GBM) cells in vitro, in part due to attenuation of their endogenous inhibitors, the cystatins. To prove that, we performed the in vivo experiments utilizing U87 xenograft NOD/SCID-eGFP mouse model. We were the first to confirm that in vivo growth of the tumour correlates with the increased cathepsin activity and decreased expression of their steffin inhibitor. By analysing primary human tissue, we managed to confirm expression of steffin A on mRNA level to associate significantly with GBM patients' survival.