Search

Matrix metalloproteinases (MMPs) play an active role in facilitating the invasion of cancer cells with excessive extracellular matrix (ECM) degradation. In the present study, we investigated the antiinvasive effects of isorhamnetin, a naturally occurring flavonoid, on MDA-MB-231 human breast carcinoma cells. The results indicated that isorhamnetin significantly inhibited the adhesion, migration, and invasion of the cells in vitro. Moreover, isorhamnetin suppressed the activity and expression of MMP-2 and MMP-9, which were determined by gelatin zymography, real-time PCR, and Western blot analysis, respectively. Besides, isorhamnetin had little effect on the secretion of urokinase plasminogen activator. Further elucidation of the mechanism revealed that isorhamnetin exerted an inhibitory effect on the phosphorylation of p38 and STAT3, although it had no effect on ERK1/2 and JNK. Taken together, these data demonstrated that isorhamnetin could significantly inhibit the invasion of MDA-MB-231 cells by downregulating the expression and activity of MMP-2 and MMP-9, which was potentially associated with the suppression of p38 MAPK and STAT3. Therefore, the findings provide new evidence for the anti-cancer activity of isorhamnetin. [ABSTRACT FROM PUBLISHER]

Abstract: Matrix metalloproteinases (MMPs) play important roles in the invasion and migration of cancer cells. In this study, we used in vitro and in vivo assays to examine the inhibitory effects of oroxylin A, one of the main bioactive flavonoid extracted from Scutellaria radix, on the human breast carcinoma cell MDA-MB-231 invasion and migration. We found that oroxylin A can suppress cell adhesion, invasion and migration in a concentration-dependent manner. Moreover, oroxylin A led to the reduction of the activity and expression levels of MMP-2 and MMP-9 in gelatin zymography, real-time PCR and western blotting analysis. Further elucidation of the mechanism revealed that oroxylin A increased the expression of tissue inhibitor of metalloproteinase-2 (TIMP-2), the endogenous inhibitor of MMP-2, and repressed the phorbol-12-myristate-13-acetate (PMA)-induced translocation of protein kinase Cδ (PKCδ), phosphorylation of extracellular signal-regulated kinase (ERK1/2) and binding activity of the transcription factor activator protein-1 (AP-1) which are upstream signaling molecules in MMP-9 expression. Our results also indicated that oroxylin A inhibited the lung metastasis of murine melanoma cell B16-F10 in vivo. Therefore, we proposed that oroxylin A might be developed as a therapeutic potential candidate for the treatment of cancer metastasis. [Copyright &y& Elsevier]