HBx-mediated increase of activated MMP-2 and cell invasion is due to the induction of MT1-MMP expression. (a) MT1-MMP expression was analyzed by Western blot in CMO, CMX, HepG2, and 2.2.15 cells grown for 24 hours in the absence of serum. (b) CMO, CMX, HepG2, or 2.2.15 cells were allowed to invade a Matrigel-coated Transwell in the presence of the anti–MT1-MMP mAb LEM 1/58 or a control antibody. The invasion was quantified as in Figure 1. (c) CMO and CMX cells were incubated for 24 hours in the presence of the anti–MT1-MMP blocking mAb LEM 1/58 or a control mAb, and the presence of MMP-2 in the cell lysates was analyzed by Western blot. (d) The presence of MT1-MMP mRNA was studied by quantitative RT-PCR in CMO and CMX cells and in Chang liver cells (CHL) transiently transfected with an HBx-expression vector or a control plasmid.