Synergistic Apoptotic Effect Of Naringenin On Enhancing The Anti-Glioma Efficacy Of Temozolomide In An In Vitro Experimental Model

Glioma is one of the most devastating and difficult-to-treat brain tumors with a very poor prognosis. Despite the current treatment modalities, the overall survival rate is only 5% contributing to a high mortality rate. Nevertheless, of emerging treatment strategies, there is still a rising need for novel mitigation strategies to counteract glioma aggressiveness. One attempt towards this long-term goal was made in this study to reveal the combined efficacy of naringenin, a bioactive flavonoid on enhancing the anti-glioma potency of temozolomide in C6 glioma cells. The cytotoxic effect of temozolomide and naringenin, both individually and in combination was assessed by employing MTT assay. The synergistic effect of the drugs temozolomide and naringenin was determined by calculating the combination index. To confirm the presence of apoptotic changes in the cells at morphological level, acridine orange/ethidium bromide staining was performed. Further, the modulatory effects of the drugs on apoptotic genes, caspase-3 and BCL-2 were evaluated using quantitative real time-PCR.Interestingly, we found that the combinatorial drug treatment was in consensus and effectively inhibited the growth of C6 glioma cells in a dose-dependent manner. Furthermore, this combinatorial drug treatment significantly up-regulated the expression of the proapoptotic gene, caspase-3 and down-regulated the anti-apoptotic gene BCL-2 suggesting a shift of equilibrium towards apoptosis. Our findings suggest that naringenin can be employed as a potent drug to enhance the anti-glioma efficacy of temozolomide and could be therapeutically exploited for the management of glioma.