A Curcumin Analog, 3,5-Bis(2′-ethoxybenzylidene)-piperidine-4-one (E145), Suppresses NF-<i>κ</i>B Signaling to Inhibit Breast Cancer Growth and Metastasis

Curcumin is a naturally occurring bioactive compound with well-characterized anti-inflammatory and antitumor properties; however, its clinical utility is limited by poor bioavailability and chemical instability. To overcome these limitations, various curcumin analogs have been developed. In this study, we investigated the antitumor and antimetastatic effects of 3,5-bis(2′-ethoxybenzylidene)-piperidine-4-one (E145), a monocarbonyl curcumin analog, with a particular focus on its ability to inhibit nuclear factor-kappaB (NF-κB) signaling in breast cancer cells. We first evaluated the effects of E145 on cell proliferation in murine 4T1 and human MDA-MB-231 breast cancer cell lines. E145 inhibited cell proliferation in a dose-dependent manner and suppressed phosphorylation of the NF-κB p65 subunit. Furthermore, E145 blocked tumor necrosis factor alpha–induced NF-κB activation by inhibiting both p65 phosphorylation and nuclear translocation. Consistently, E145 reduced the expression of NF-κB–regulated pro-tumorigenic factors, including vascular endothelial growth factor, matrix metalloproteinase-9, interleukin-1β (IL-1β), and IL-6. Functional assays demonstrated that E145 markedly suppressed the migration and invasion of breast cancer cells in vitro. In addition, experimental lung metastasis assays revealed that E145 treatment significantly reduced metastatic colonization of 4T1 cells in vivo. Collectively, these findings indicate that E145 exerts potent antimetastatic effects by inhibiting cell-intrinsic NF-κB activation and downstream inflammatory mediators. These results suggest that E145 is a promising therapeutic candidate for targeting NF-κB–driven breast cancer progression and metastasis.