Abstract 3732: New aspirin analogs for targeted therapy of ER+ breast cancers with activated NFkB inflammatory pathway

Abstract

Abstract Approximately 75% of breast cancers express estrogen receptor (ER), classified as either ER+ luminal A or luminal B. Five year survival rate of luminal B breast cancers is ∼50% compared to ∼95% for luminal A, making luminal B subtype a target for better understanding the mechanisms of carcinogenicity and improved therapy. Inflammation and activation of its nuclear factor NFkB, is linked clinically and epidemiologically to cancer. Activation of NFkB in a subset of ER+ cancers is associated with poor prognosis and resistance to therapy. We were the first to show synergy between ER and NFkB in a specific gene signature that highly correlates with luminal B ER+ breast cancers, suggesting a potential functional role for NFkB inhibition in this subset. Based on these findings, we hypothesized that co-targeting ER and NFkB may achieve clinical efficacy in luminal B breast cancer. To target the ER, a selective estrogen receptor modulator (SERM) was employed. To target NFkB pathway, an NSAID-based therapy would be safe and, based on epidemiological data, is suggested to be chemopreventive in breast cancer. For NFkB targeting, we characterized a family of aspirin (ASA)-based analogs (x-ASA) that also serve as pro-drugs for quinone methide formation. We found that x-ASA analogs inhibited TNFa induction of NFkB via a reporter assay in a dose-dependent fashion in MCF-7 cells, and also shut down several genes typically up-regulated by the ER-NFkB crosstalk. Next we tested the co-targeting approach in mammosphere formation assays: the combination significantly reduced overall mammosphere number and size. While the mechanisms of action remains to be elucidated, the aspirin analogs in combination with a SERM show promise in treating ER+ breast cancers with activated NFkB where standard endocrine therapy alone fails. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3732. doi:1538-7445.AM2012-3732