Inhibition of neuroblastoma cell proliferation and invasion by a non-phosphorylable mutant of MT1-MMP. NB-10 and SK-N-SH neuroblastoma cells were transfected with either pcDNA, WT or Y573F forms of MT1-MMP. 24 h post-transfection, cells were harvested and transfection efficiency as well as MT1-MMP phosphorylation levels were determined by Western blot (A); IP: immunoprecipitation, ID: immunodection, H: immunoglobulin heavy chain. (B) 5 × 104 transfected cells were subjected to migration assays, using Transwells pre-coated with 10 μg/ml type I collagen and 10% serum as chemoattractant. (C) 2 × 104 transfected cells were embedded within type I collagen gels and allowed to grow during 5 days. Data are means ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001.