MMP9 and glioma: Matrix metalloproteinases (MMPs), such as MMP-2 and MMP-9, play important roles in the invasion and malignancy of glioma cells.19 After U87 and U251 cells were treated with amlexanox at various concentrations for 72 h, the protein expression levels of MMP-2 and MMP-9 were checked by western blot (Figure 3g).