Abstract 1295: Evaluation of the efficacy of TRAIL plus quercetin as a potential breast carcinoma therapeutic
Authors: Manouchehri Jasmine M. , Kalafatis Michael , Lindner Daniel 
Published: July 2016

Breast cancer is the most commonly diagnosed cancer in women in the United States. There is a continued need for the development of selective and specific treatment options for all types of breast cancer, including hormone-dependent and triple-negative subtypes. Recombinant human Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (rhTRAIL), the optimized form of the endogenous death ligand, shows potential as an effective anti-cancer therapeutic due to its ability to induce apoptosis in cancer independent of wild-type p53 function, while displaying minimal toxicity to normal cells. However, a majority of breast cancer cell lines exhibit resistance to TRAIL treatment due to up-regulation of pro-apoptotic proteins, down-regulation of anti-apoptotic proteins, and/or up-regulation of death receptors 4 and 5. To overcome TRAIL resistance, a cotreatment option has been explored utilizing the natural compound Quercetin (Q). Q is a flavonol found in certain fruits, vegetables, and teas. As a single agent, Q has been shown to have antiproliferative and pro-apoptotic effects on a variety of cancer cell lines. The aim of this study is to examine the capacity of Q to enhance TRAIL's pro-apoptotic and antiproliferative effects on breast cancer cells. Sulphorhodamine B (SRB) assays were performed on hormone dependent (MCF-7) and triple negative (BT-20) breast cancer cell lines to determine if the cotreatment of Q and TRAIL hinders cell growth. Growth for both MCF-7 and BT-20 cells was substantially inhibited by single agent Q treatments (12.5 μM; ∼20%, 25 μM; ∼40%, 50 μM; ∼60%) but not by single agent TRAIL treatment (100 ng/mL; &lt;20%). Moreover, BT-20 and MCF-7 cell growth was further inhibited by cotreatment with both agents; for example, the cotreatment of 50 μM Q and 100 ng/mL TRAIL inhibited BT-20 and MCF-7 cell growth by 80% and 90%, respectively. As a single agent, Q was able to induce apoptosis in a dose-dependent manner in both breast cancer cells; thereafter, Q's ability to sensitize breast cancer cells to TRAIL-induced apoptosis was examined by western blot analysis. Compared to single agent treatments, the combination of Q and TRAIL enhanced the induction of apoptosis as indicated by increased PARP cleavage (a hallmark of apoptosis) and the activation of the executioner caspases 3 and 7. Furthermore, the cotreatment of breast cancer cells with Q and TRAIL enhanced the activation of the extrinsic and intrinsic apoptotic pathways, as assessed by the activation of caspase 8 and the release of cytochrome c from the mitochondria, respectively. Overall, these findings suggest that the cotreatment of Q and rhTRAIL possesses the potential to be an anti-breast cancer therapeutic by enhancing pro-apoptotic and anti-proliferative effects in hormone dependent and triple-negative breast cancer cells.

Citation Format: Jasmine M. Manouchehri, Michael Kalafatis, Daniel Lindner. Evaluation of the efficacy of TRAIL plus quercetin as a potential breast carcinoma therapeutic. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1295.