Effect of CD147 antagonistic peptide 9 (AP9) on the invasive ability of the co-culture cells. (a) The haematoxylin and eosin staining results of the lower surface filters show that the cells had invaded through the filter and attached to the lower side of the filter (× 150). In the co-culture of undifferentiated THP-1 cells and HFC, the number of cells was increased compared with the cultures of THP-1 cells or HFC alone. (b) Effect of AP9 on the number of cells that invaded through the Matrigel coated filter in the co-culture of undifferentiated or differentiated THP-1 cells and HFC. The number of cells that invaded through the filter was counted, showing that when AP9 was added the number of cells decreased. Asterisks indicate a p-value <0.01. (c) Effect of AP9 on the number of cells that invaded through the Matrigel coated filter in a co-culture of human CD14+ monocytes and HFC. The number of cells decreased when AP9 was added. Asterisks indicate a p-value < 0.05. HFC, Human fibroblast cells.