Abstract
Orostachys japonicus has been used in traditional medicine as an anticancer agent. The present study aimed to investigate the mechanism by which O. japonicus extract affects the expression of matrix metalloproteinase (MMP)-2 and MMP-9, its association with the expression of the inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) genes in phorbol myristate acetate-differentiated THP-1 human monocytic leukemia cells and how it mediates the nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) pathways. Cell proliferation was analyzed by MTT assay, mRNA expression was detected by quantitative polymerase chain reaction and protein expression was measured by western blot analysis. It was demonstrated that O. japonicus suppressed the mRNA expression of MMP-2 and MMP-9. In addition, O. japonicus was found to downregulate iNOS and COX-2 transcription and translocation. Furthermore, O. japonicus inhibited NF-κB p65 activity as well as the phosphorylation of p38 MAPK, MAPK kinase (MEK) and extracellular signal regulated kinase (ERK). The present results suggested that O. japonicus inhibited not only MMP-2 and MMP-9 mRNA expression, but also iNOS and COX-2 gene expression, suppressed NF-κB activation and reduced phosphorylation of p38 MAPK, MEK and ERK. The present results therefore indicated that O. japonicus was able to inhibit the expression of MMP-2 and MMP-9 and suppress the transcription and translocation of iNOS and COX-2 by directly inhibiting the activation of NF-κB and the phosphorylation of the MAPK pathway in THP-1 cells.