Effect of resveratrol on the expression of anti-apoptotic genes in breast cancer cells

Background and Objectives Breast cancer remains the most frequent malignancy among women worldwide. The complex tumor microenvironment, aggressive behavior, heterogenous nature, high rate of proliferation, and treatment resistance are among breast cancer's most well-known characteristics. Most of these processes are related to the ability of cancer cells to evade apoptosis. One way cancer cells prevent apoptosis is by overexpressing anti-apoptotic genes. Therefore, reducing the expression of anti-apoptotic genes can activate the apoptosis mechanism and thus increase the sensitivity of cells to cancer treatment. Although chemical treatments are successful in treating cancer, their side effects and resistance often lead to treatment failure. Therefore plant-derived chemicals have attracted a lot of attention due to their ability to efficiently inhibit cancer cell survival and induce sensitivity to cancer treatment. One of these phytochemicals is resveratrol (RSV) which can be found in common foods, such as pistachios, peanuts, bilberries, blueberries, and grapes. RSV is a phytoestrogen that possesses antioxidant, antiinflammatory, cardioprotective, and anti-cancer properties. Several investigations demonstrated that RSV could trigger apoptosis and suppress the expression of genes specific to malignancy. Thus, this study aimed to investigate the in vitro effects of RSV on the expression of anti-apoptotic genes BCL-2, MCL-1 and BCL-XL in breast cancer cells. Material and Method In this study, cell lines from different subtypes of breast cancer were used: the MCF-7 cell line is the luminal A and the MDA-MB-231 cells are the triple negative subtype. To determine the expression of the anti-apoptotic BCL-2, MCL-1, and BCL-XL genes, we used reverse transcription-quantitative PCR (RT-qPCR). Cells were seeded in 6- well plates and incubated overnight. The next day, cells were treated with 50 µM and 80 µM concentrations of RSV or with DMSO as a control (0 µM). After 48 hours of incubation time, the total RNA was extracted from cells using the RNeasy Mini Kit according to the manufacturer’s instructions. The High-Capacity RNA-to-cDNA Kit was used to produce cDNA from 1 µg of total RNA. RT-qPCR analysis was performed on a QuantStudio3 Real-Time PCR System. Relative gene expression was normalized to β-actin. Statistical significance was established using Student's t-tests. The result was considered statistically significant if p<0.05. Results RT-qPCR analysis showed that RSV significantly reduced the expression of BCL-2, MCL-1 and BCL-XL genes in the MDA-MB-231 cell line. Compared with the untreated control group, after the treatment with 50 µM and 80 µM concentrations of RSV, the BCL-2 gene expression was reduced to 0.76 and 0.73, MCL-1 gene expression decreased to 0.41 and 0.42, BCL-XL gene expression was 0.38 and 0.40, respectively. In MCF-7 cells, only the BCL-2 gene expression decreased to 0.79 and 0.85 after the treatment with 50 µM and 80 µM concentrations of RSV, respectively. The expression of the MCL-1 and BCL-XL genes did not alter significantly. Our findings demonstrate that RSV had a stronger impact on anti-apoptotic genes expression in the MDA-MB-231 cell line, than in MCF-7. Conclusion and recommendations Our study results revealed that RSV reduced the expression of anti-apoptotic BCL-2, MCL-1, and BCL-XL genes in breast cancer cells. However, the effectiveness of RSV depends on the subtype of breast cancer. The triple negative breast cancer cell line MDA-MB-231 was more sensitive to the effects of RSV and may be a potential target for RSV therapy.