Abstract 2908: Function and regulation of peroxiredoxin proteins in doxorubicin-treated MCF-7 breast cancer cells.

Abstract

Abstract The Peroxiredoxin (Prdx) family of genes encodes thiol-specific antioxidant proteins that protect cells from oxidative stress. Mammalian cells express six different Prdx proteins, and these proteins play a role in cell signaling, proliferation and apoptosis. Recent studies have shown that Prdx levels are elevated in many cancers, suggesting that Prdx upregulation may be an advantageous adaptation to the cancerous state. In the present study we investigated the expression and function of different Prdx proteins in untreated and doxorubicin-treated MCF-7 breast cancer cells, as well as noncancerous MCF-10A cells. We used real-time PCR and western blotting to examine Prdx expression in both cell lines, and also measured Prdx protein expression in doxorubicin-treated MCF-7 cells. In addition, we suppressed Prdx expression using transiently transfected siRNA and measured cell proliferation and apoptosis. Our results show that MCF-7 cells are significantly more resistant to cell death induced by the chemotherapy agent doxorubicin. We also found that five of the six Prdxs are overexpressed in MCF-7 cells at the mRNA and protein levels, and that serum deprivation reduced Prdx expression. Treatment of MCF-7 cells with doxorubicin altered expression of specific Prdxs, demonstrating a specific effect on these antioxidants. Transient transfection of MCF-7 cells with Prdx6 siRNA resulted in a marked reduction in Prdx6 suppression, with no change in other Prdx proteins. Suppression of Prdx6 in these cells led to reduced cell proliferation and increased susceptibility to doxorubicin-induced death. Similar studies are currently underway for the other Prdx proteins. Together, these findings suggest that Prdx overexpression in MCF-7 cells may be cytoprotective and that Prdxs may contribute to doxorubicin-resistance in these and other breast cancer cells. Citation Format: Caitlin McDonald, Gregg Perlmutter, Kekoa Taparra, Jillian Muhlbauer, Julie Passarelli, Shelley A. Phelan. Function and regulation of peroxiredoxin proteins in doxorubicin-treated MCF-7 breast cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2908. doi:10.1158/1538-7445.AM2013-2908