Polysaccharide from Inonotus obliquus inhibits migration and invasion in B16-F10 cells by suppressing MMP-2 and MMP-9 via downregulation of NF-κB signaling pathway

Polysaccharides derived from Inonotus obliquus (PIO) are known to possess multiple pharmacological activities including antitumor activity. However, the possible molecular mechanisms of these activities are unknown. In the present study, we determined the anti-metastatic potential and signaling pathways of PIO in the highly metastatic B16-F10 mouse melanoma cell line in vitro. We found that PIO suppressed the migration and invasive ability of B16-F10 cells and decreased the expression levels and activities of matrix metalloproteinase (MMP)-2 and MMP-9. In addition, PIO decreased the phosphorylation levels of extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK); PIO also decreased the expression level of cyclooxygenase (COX)‑2 and inhibited the nuclear translocation of nuclear factor κB (NF-κB) in B16-F10 melanoma cells. These results suggest that PIO could suppress the invasion and migration of B16-F10 melanoma cells by reducing the expression levels and activities of MMP-2 and MMP-9 through suppressing MAPK, COX-2 and NF-κB signaling pathways.