Evaluation of Apoptotic and Autophagic Effects of Thioridazine in Monolayer and Spheroid Cell Cultures

INTRODUCTION: Glioblastoma (GBM) is the most frequently seen brain tumor in adults. It is clear that new therapeutic agents are needed in this area. Spheroid cell cultures have advantages on imitating in vivo environment. Therefore, we investigated apoptotitac and autophagic effects of Thioridazine (THZ) which is a potential anti-cancer agent on GBM cell lines, T98G and U-87 MG, comparatively in monolayer and spheroid cell cultures.
METHODS: The cytotoxic effect of THZ on cells was evaluated by MTT method. Besides, apoptotic and autophagic effects of THZ were determined by Annexin V and LC-3 antibody based methods. Validation performed also by assessment of apoptosis and autophagy with specific inhibitors.
RESULTS: The analysis has revealed that IC50 values at 24 h were 12,67 μM (T98G) and 12.80 μM (U-87 MG) in monolayer cell culture, 29.30 μM (T98G) and 28.68 μM (U-87 MG) in spheroid cell culture. While apoptotic cell rate was determined at 24 h approximate 15% in both cell lines and cell cultures, autophagy induction rate was increased by 6.5- (T98G) and 5.6- (U-87 MG) fold in monolayer cell culture and by 3.3- (T98G) and 4.5- (U-87 MG) fold in spheroid cell culture.
DISCUSSION AND CONCLUSION: In our study THZ stimulates mostly autophagy rather than apoptosis. In addition, it can be suggested that in vitro cytotoxicity studies should perform with not only monolayer cell cultures but also with spheroid cell cultures for obtaining in vivo-like data. When all the evaluations are considered, THZ might be thought as a potential chemotherapeutic agent in the treatment of GBM.