Abstract 89P
Background
Glioblastoma multiforme (GBM) is one of the most common and aggressive primary brain tumors in adults with very poor prognosis. The treatment is complex and consists of the surgical resection followed by chemoradiotherapy using alkylating drug temozolomide (TMZ), which is problematic due to fast developing chemoresistance. Novel therapeutic approaches for GBM treatment are needed such as combination therapy where TMZ effect might be potentiated by other useful compound/s. The aim of this study was to investigate the effect of potential anticancer drug flubendazole (FLU) on TMZ treated GBM cell lines A172 and T98G and to verify potential improved efficiency of this combination towards GBM cells.
Methods
The effect of TMZ, FLU and their combination on GBM cell lines was evaluated by cell proliferation assay (WST-1) and changes in cellular morphology (phase contrast microscopy). Morphology and organization of microtubules in treated cells were examined by fluorescence microscopy. Selected tubulins as well as markers of STAT3 signaling and cell cycle regulation were determined by western blotting and IHC analysis. Quantification of TMZ and FLU in exposed cells was carried out by LC/MS analysis.
Results
In both tested cell lines, combination of TMZ + FLU showed a more significant inhibitory effect on the GBM cells proliferation as compared to single FLU and TMZ. Moreover, combined use of FLU and TMZ enhanced accumulation of both compounds inside the cells and produced significant changes in cell morphology and microtubule structure. In addition, in thus treated cells the expression and activation of STAT3 was inhibited resulting in a decrease in cdc2 and cyclin B1 levels, suggesting possible G2/M cell cycle arrest. Since STAT3 and its activated form were also found in clinical samples, it can be discussed as a relevant marker and possible target.
Conclusions
The use of FLU significantly improved TMZ effect in tested GBM cell lines. The employed drug combination markedly altered cellular microtubule network and STAT3 signaling pathway, resulting in cell cycle arrest at G2/M phase and subsequent mitotic catastrophe.
Editorial acknowledgement
This study was supported by Ministry of Health, Czech Republic, project No. NU20-03-00360.
Legal entity responsible for the study
The authors.
Funding
Ministry of Health, Czech Republic, project No. NU20-03-00360.
Disclosure
All authors have declared no conflicts of interest.