Anti-glioma effect of Turkish propolis in C6 cells via regulation of COX-2 and NF-κB mRNA expression and redox homeostasis.

This study aims to determine whether Turkish propolis applied to C6 glioma cells has an anti-glioma effect. To investigate this, C6 glioma cells were treated with propolis extract concentrations of 100, 250 and 500 µg/ml. COX-2 and NF-κB mRNA expressions in the cells were detected by using qPCR. The levels of TNFα, MMP-2, -9 and JNK/SAPK in the cells were analyzed by using ELISA. The changes in redox status biomarkers as oxidant and antioxidant status and cell injury biomarkers were detected by using colorimetric methods or ELISA. COX-2 and NF-κB mRNA expression levels were decreased in glioma cells treated with propolis extract at concentrations of 100, 250 and 500 µg/ml as compared to control cells. MMP-2 and -9 levels were unchanged, while TNFα levels decreased in C6 glioma cells treated with propolis extract at concentrations of 100, 250, 500 µg/ml compared to control cells. While the levels of dityrosine, kynurenine, AOPP, advanced glycation end products and lipid hydroperoxides were significantly decreased in C6 glioma cells treated with 100µg/ml propolis compared to control cells, it increased significantly in cells treated with propolis extract at 500µg/ml concentration. These findings suggest that Turkish propolis may exert anti-glioma effects on C6 glioma cells by dose-dependently regulating COX-2 and NF-κB mRNA expressions and promoting oxidative stress-induced cell damage and death.