Kiss-1 expression had an significant impact on MMP-9. A and B. The overall MMP-9 gene expression was increased in HT115 Kiss-1 knockdown cells as shown by RT-PCR (A) and by real-time quantitative PCR (B). C. The enzyme activity of MMP-9 and MMP-2 in HT115 pEF and HT115 Kiss-1 knockdown cells, following treatment (no treatment, Kisspeptin-10 and Kisspeptin-234). (cells + ERK inhibitor vs control in the group of no treatment: p = 0.006577; cells + ERK inhibitor vs control in the group of Kisspeptin-10: p = 0.001839; cells + ERK inhibitor vs control in the group of Kisspeptin-234: p = 0.005935). D. The difference between MMP-9 enzyme activity in three groups of HT115 pEF cells (left) and HT115 Kiss-1 knockdown cells (right). + represents for corresponding treatment. Experiment was repeated three times and mean value taken.