Glioblastoma multiforme (GBM) is the most aggressive form of brain tumour and contains a population of non-differentiated cells called glioblastoma stem cells (GSC). These cells are capable of self-renovation, they have unlimited capability to divide and the capacity to differentiate themselves into other tumour cells as well. It has also been proven that this population of cells can regenerate tumour mass after it has been removed. This leads to the presumption that they can become an important target in GBM treatment. The goal of the treatment is to eradicate every GSC, but because of their resistance to chemo- and radiotherapy, this issue remains unresolved.
In this master thesis research, we were investigating the role of cysteine peptidase cathepsin X in glioblastoma stem-like cells (GSCs). Cathepsin X impacts migration and invasion of GSCs and therefore plays an important role in tumour progression. We used glioblastoma cell line U87, which can form cell clusters, so called spheroids, which protect them from external stimuli. Our results indicate that the stimulation of U87 cells increases the expansion of GSCs. Moreover, we demonstrated overexpression and localization of cathepsin X in GSCs. We confirmed that cathepsin X has a significant role in GSCs and could be an important target in the GBM treatment.
To sum up the investigation we observed the expansion of GSCs by stimulating U87 cells with the presence of a specific inhibitor of cathepsin X. We showed that by the selective cathepsin X inhibition, there was observed a significant impact in the expansion of GSCs. In this context we believe that cathepsin X plays an important role in GBM tumour progression.