Induction of matrix metalloproteinase-9 by galectin-7 through p38 MAPK signaling in HeLa human cervical epithelial adenocarcinoma cells

The expression of matrix metalloproteinase-9 (MMP-9) has been reported in various cancers. Its expression is associated with tumorigenesis and tumor metastasis. Studies have shown that galectin-7, a beta-galactoside-binding animal lectin, is involved in various processes including the suppression of tumor growth. However, a recent study reported that the development of thymic lymphoma is accelerated by galectin-7 expression. In this report, we demonstrate that the expression of MMP-9 was increased by galectin-7 in human cervix epithelial cells (HeLa). When the galectin-7 gene was transfected to HeLa cells with the ECFP vector, the expression of MMP-9 mRNA increased, as compared to non-transfected cells. As a result, MMP-9 protein levels also increased, as indicated by Western blot and gelatin zymography. In addition, galectin-7-transfected cells exhibited increased invasion in the matrigel invasion system. Expression of MMP-9 is involved in several signaling pathways by various stimulation factors. Therefore, we investigated how the signaling pathway in galectin-7-transfected cells differs from that of non-transfected cells. Upon transfection of galectin-7, p38 MAPK was activated and SB203580, a chemical inhibitor of p38 MAPK, reversed the effects of galectin-7. These results indicate that galectin-7 increases the expression of MMP-9 through the p38 MAPK signaling pathway.