Study of autophagy and cell death induction in MCF-7 cells in the presence of quercetin

In this study, induction of death autophagy in the presence of quercetin was investigated in MCF-7 cells. At first, the effective dose of quercetin, resulting in 50 percent death in cellular population (LC50), was determined as 220 M using MTT assay. Ascertaining of the main type of cellular death was carried out using flow cytometry and its usual probes including Annexin-FITC and PI. Accordingly, the main type of cellular death mechanism in quercetin treatment was apoptosis with total percent value of 54%.Determination of effective mechanisms for cell death induction was performed using real time RT-PCR. Selected apoptotic genes in this study were p53, Bax, Bcl-2, Casp-3. Significant decrease in Bcl-2 expression, with respect to its anti-apoptotic effects, showed that the breast cancer cells were being sensitized for apoptosis in the presence of quercetin. Increasing the Bax/Bcl-2 ratio shows that, despite of the constant expression of Bax gene, the increased sensitivity of the cells for apoptosis is occurred via decreasing of the expression level of Bcl-2 gene. Study of quercetin effects for autophagy induction was carried out after nominating of mTOR, LC3, Beclin1 and DRAM genes and analysing their expression variations in the presence of quercetin. Decreased expression of mTOR alongside rigorous increase in LC3 expression totally supports autophagy induction. This notion was also confirmed by LC3II antibody and immunocytochemistry investigations. Our results showed that quercetin is able to induce death autophagy to kill breast cancer cells.