Antimetastatic effect and mechanism of ovatodiolide in MDA-MB-231 human breast cancer cells

Cancer metastasis is a primary cause of cancer death. Ovatodiolide, a bioactive cembrane-type diterpenoid isolated from Anisomeles indica (L.) Kuntze (Labiatae), has been shown to inhibit the growth and proliferation of cancer cells. However, the anti-metastatic effects of ovatodiolide on highly metastatic human breast cancer MDA-MB-231 cells remain unclear. In this study, we first noted that ovatodiolide inhibited MDA-MB-231 cell migration and invasion by wound-healing assay and Boyden chamber assay. Western blot, gelatin zymography and reversed transcription-PCR analysis showed that ovatodiolide significantly and selectively suppressed the expression, activation, and mRNA of matrix metalloproteinase-9 (MMP-9) in a concentration-dependent manner. Ovatodiolide significantly decreased the nuclear level of nuclear factor kappaB (NF-κB), increased inhibitor of kappaBα (IκBα) through preventing phosphorylation of upstream signal IκB kinase (IKK). Pretreatment with a specific NF-κB inhibitor (PDTC) and an IκB protease inhibitor (TPCK) also reduced MMP-9 activity, cell migration and cell invasion. Moreover, ovatodiolide can suppress activation of c-Jun N-terminal kinase, p38 mitogen-activated protein kinase, phosphatidylinositol 3-kinase and Akt, while it did not affect phosphorylation of extracellular signal regulating kinases (ERK)1/2. Additionally, the treatment of inhibitors specific for PI3K (wortmannin), JNK (SP600125) or p38 MAPK (SB203580) to MDA-MB-231 cells could result in a reduced activation of MMP-9, concomitantly with a marked inhibition on cell migration and invasion. Taken together, these results demonstrate that ovatodiolide inhibits the metastatic ability of MDA-MB-231 cells by reducing MMP-9 activity through suppressing JNK, p38 MAPK and PI3K/Akt signaling pathways and inhibiting NF-κB activity. These results are the first to reveal the function of ovatodiolide in tumor metastasis and its underlying molecular mechanism, thus suggesting ovatodiolide to be a promising antimetastatic agent.

Ovatodiolide, a cembrane-type diterpenoid, is the major component of Anisomeles indica (L.) Kuntze (Labiatae). This plant has been traditionally used for treatment of gastric dysfunction, inflammatory disorders, and hypertension in China and India. The aim of this study is to determine whether ovatodiolide inhibited the metastasis in MDA-MB-231 cells and to further explain its possible mechanisms.Figure optionsDownload as PowerPoint slideHighlights
► Ovatodiolide inhibited MDA-MB-231 cell migration and invasion.
► Ovatodiolide suppressed the MMP-9 activity.
► Ovatodiolide decreased NF-κB activity.
► Ovatodiolide suppressed the activation of JNK, p38 MAPK, and PI3K/Akt.