Objective: To explore the regulatory mechanism of matrix metalloproteinase-9 (MMP-9) gene expression induced by phorbol 12-myristate 13-acetate (PMA) in cytotrophoblastic cells.
Methods: Enzyme-linked immunosorbent assay (ELISA) was used to determine the kinase activity, and MMP-9 gene expression was detected by semi-quantitative reverse transcription (RT)-PCR in the cytotrophoblastic cells.
Results: Cytotrophoblastic cells treated with PMA showed markedly increased MMP-9 mRNA level. PMA treatment caused an increase in extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK) activities. Both SB203580 (specific inhibitor of the p38 MAPK) and PD98059 (specific inhibitor of the ERK), when preincubated for 30 min with the cytotrophoblastic cells, substantially reduced MMP-9 mRNA accumulation in PMA-primed cells. However, neither SB203580 nor PD98059 used alone, or their combination, was able to completely inhibit MMP-9 mRNA expression.
Conclusion: Both p38 MAPK and ERK pathways are involved in the regulation of MMP-9 gene expression in the cytotrophoblastic cells induced by PMA, and both signaling pathways are indispensable for full activation of MMP-9 gene expression.