Timosaponin AIII inhibits melanoma cell migration by suppressing COX‐2 and in vivo tumor metastasis

摘要

Melanoma is the leading cause of death from skin disease, due in large part to its propensity to metastasize. We examined the effects of timosaponin AIII, a compound isolated from Anemarrhena asphodeloides Bunge, on melanoma cancer cell migration and the molecular mechanisms underlying these effects using B16‐F10 and WM‐115 melanoma cells lines. Overexpression of COX‐2, its metabolite prostaglandin E2 (PGE 2), and PGE 2 receptors (EP2 and EP4) promoted cell migration in vitro. Exposure to timosaponin AIII resulted in concentration‐dependent inhibition of cell migration, which was associated with reduced levels of COX‐2, PGE 2, and PGE 2 receptors. Transient transfection of COX‐2 siRNA also inhibited cell migration. Exposure to 12‐O‐tetradecanoylphorbal‐13‐acetate enhanced cell migration, whereas timosaponin AIII inhibited 12‐O‐tetradecanoylphorbal‐13‐acetate‐induced cell migration and reduced basal levels of EP2 and EP4. Moreover, timosaponin style="fixed-case">AIII inhibited activation of nuclear factor‐kappa B ( style="fixed-case">NF‐κB), an upstream regulator of style="fixed-case">COX‐2 in B16‐F10 cells. Consistent with our in vitro findings, in vivo studies showed that timosaponin style="fixed-case">AIII treatment significantly reduced the total number of metastatic nodules in the mouse lung and improved histological alterations in B16‐F10‐injected C57 style="fixed-case">BL/6 mice. In addition, C57 style="fixed-case">BL/6 mice treated with timosaponin style="fixed-case">AIII showed reduced expression of style="fixed-case">COX‐2 and style="fixed-case">NF‐κB in the lung. Together, these results indicate that timosaponin style="fixed-case">AIII has the capacity to inhibit melanoma cell migration, an essential step in the process of metastasis, by inhibiting expression of style="fixed-case">COX‐2, style="fixed-case">NF‐κB, style="fixed-case">PGE 2, and style="fixed-case">PGE 2 receptors.