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

Abstract

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