Selective and oxidative stress-mediated cell death of MCF-7 cell line induced by terpinolene

In this study, we compared the effects of terpinolene against the anti-cancer agent cisplatin on proliferation, apoptotic activity and intracellular ROS (reactive oxygen species) production in cancerous (MCF-7) and non-cancerous (HEK-293) cell lines. Cisplatin presented a strong growth-inhibitory effect on both MCF-7 (IC 25 : 18.77 µM) and HEK-293 (IC 25 : 15.03 µM) cell lines. The growth-inhibitory effect of terpinolene was found to be weaker than cisplatin (IC 25 : 291.18 µM for MCF-7 and 345.35 µM for HEK 293 cells). The expression levels of BAX (by 1.86-fold), cleaved-PARP (by 2.23-fold) and pro-caspase-8 (by 1.74-fold) proteins increased in response to terpinolene treatment in MCF-7 cells. Curiously, the increase in the expression levels of these apoptotic markers was less pronounced in terpinolene-treated non-cancerous HEK 293 cells. Terpinolene, promoted a higher rate of apoptotic and necrotic cell death on MCF-7 cells (apoptotic cells: 25.28 %; necrotic cells: 17.70 %) when compared with HEK-293 cell line (apoptotic cells: 15.47 %; necrotic cells: 9.42 %). Interestingly, terpinolene caused a marked increase (2.05-fold) in intracellular ROS production in MCF-7 cells while HEK-293 cells appeared to be resistant to terpinolene or cisplatin treatments. In conclusion, although terpinolene showed a weaker growth-inhibitory effect on MCF-7 cancer cells, it exhibited a better selectivity than cisplatin in inducing cell death and intracellular oxidative stress in MCF7 breast cancer cells.