Characterization of Apoptosis in a Breast Cancer Cell Line after IL-10 Silencing

BACKGROUND: Breast cancer is affected by the immune system in that different cytokines play roles in its initiation and progression. Interleukin-10 (IL-10), an anti-inflammatory cytokine, is an immunosuppressive factor involved in tumorigenesis. The present study was conducted to investigate the gene silencing effect of a small interference RNA (siRNA) targeting IL-10 on the apoptotic pathway in breast cancer cell line. METHODS: The siRNA targeting IL-10 and a glyceraldehyde 3-phosphate dehydrogenase (GAPDH) clone were introduced into MDA-MB-231 cells. Real-time PCR assays were used to determine IL-10 and GAPDH gene expression levels, in addition to those for protein kinase B (AKT), phosphoinositide 3-kinase (PI3K), B-cell lymphoma 2 (Bcl2), caspase-3 and caspase-9 genes related to apoptosis. RESULTS: Inhibition of IL-10 by the siRNA accelerated apoptosis and was accompanied by significant increase in caspase-3 and caspase-9 and a significant decrease in PI3K, AKT and Bcl2 expression levels compared to the non-transfected case. CONCLUSIONS: In conclusion, the production of IL-10 may represent a new escape mechanism by breast cancer cells to evade destruction by the immune system. IL-10 gene silencing causes down regulation of both PI3K/AKT and Bcl2 gene expression and also increases the Bbc3, BAX caspase3, and caspase 3 cleavage expression levels. IL–10 might represent a promising new target for therapeutic strategies.