Sesamol inhibits proliferation, migration and invasion of triple negative breast cancer via inactivating Wnt/β-catenin signaling

Triple negative breast cancer (TNBC), a particularly aggressive breast cancer subtype without estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2) expression, possesses highly invasive capacity, uncontrolled proliferative phenotype and poor clinical prognosis. Sesamol enriched in sesame seeds has been widely reported as a metabolic modulator due to its anti-aging, anti-hepatotoxic and cardio-protective properties. In this study, we found that sesamol significantly inhibited proliferation, migration and invasion of TNBC cells via attenuating PCNA, CyclinD1 expression and reversion of epithelial-mesenchymal transition (EMT) characterized by increased epithelial marker E-cadherin and decreased mesenchymal marker N-cadherin, Vimentin, Snail expression. Moreover, sesamol inactivated Wnt/β-catenin signaling and Wnt agonist 1 AMBMP application reversed the inhibition of proliferation, migration and invasion of TNBC by sesamol administration. Subsequently, our data showed that sesamol induced Wnt inhibitory factor 1 (WIF1), an endogenous inhibitor of Wnt/β-catenin pathway, expression and WIF1 artificial knockdown abrogated the inactivation of Wnt/β-catenin signaling by sesamol exposure in TNBC cells. And we found that promoter region de-methylation was responsible for WIF1 up-regulation by sesamol administration. Finally, with the xenograft assay using nude mice, we also found that sesamol inhibited proliferation and metastasis of TNBC via WIF1-induced inactivation of Wnt/β-catenin signaling in vivo. Collectively, these data added novel understandings and evidences to the anti-cancer properties of sesamol.