The rate of HT1080 invasion is dependent on MT1-MMP. HT1080 cells transfected with siRNA targeting Luciferase (A), MT1-MMP (custom) (B), or scrambled MT1-MMP (C) were seeded onto 3.75 mg/ml collagen gels in glass casings (see methods for details) and allowed to invade for 48 hours in the presence 1 μM LPA. Data were collected as in Fig. 3 and were plotted versus time (D). Rates of invasion were calculated using linear regression (see Table 1). Data are expressed as mean rate of invasion (n = 3 wells, ± S.D.) for each time point from triplicate experiments. Magnification = 10×. Scale bars = 200 μm. Dashed line indicates front of tumor cell invasion. si = siRNA; Luc = Luciferase, MT1-C = custom MT1-MMP, MT1-sc = scrambled MT1-MMP.