Anti-invasive effect of β-myrcene, a component of the essential oil from Pinus koraiensis cones, in metastatic MDA-MB-231 human breast cancer cells

The invasive potential of malignant tumor cells is critical for their metastasis. This study was undertaken to evaluate the anti-invasive activity of β-myrcene, a natural compound found in the essential oil from Pinus koraiensis cones (EOPC), in metastatic MDA-MB-231 human breast cancer cells. Among four major constituents that included α-pinene, β-myrcene, 3-carene, and d-limonene, β-myrcene showed the most potent inhibition of tumor necrosis factor-α (TNFα)-induced nuclear factor κB (NF-κB) activity. Pretreatment with β-myrcene suppressed TNFα-induced phosphorylation of inhibitor of κB kinase and NF-κB as well as matrix metalloproteinase-9 (MMP-9) gene expression in a dose-dependent fashion. Furthermore, β-myrcene inhibited TNFα-induced invasion of MDA-MB-231 cells as determined by three-dimensional spheroid invasion assays. These findings suggest that EOPC may promote anti-metastatic activity in breast cancer cells through its downregulation of NF-κB-mediated MMP-9 expression.