Control of smooth muscle cell function by membrane-type matrix metalloproteinases.

Vascular smooth muscle cells (SMCs) express membrane-type matrix metalloproteinases-1 and -3 (MT1- and MT3-MMPs). Expression is induced by PDGF in culture or by balloon injury in rat carotid arteries. In this study, we tried to define their functions in SMCs by transducing MT1- and MT3-MMP cDNAs into baboon-cultured SMCs, using adenoviral vectors. Overexpression of MT1-MMP increased the conversion of proMMP-2 to the activated form. In contrast, in MT3-MMP overexpressing cells, MMP-2 activation was partial. However, both MT1- and MT3-MMP overexpression elicited morphological alterations (cell rounding), which was prevented by BB94 addition. The cells, which underwent this change, showed reduced adhesion to matrices and increased migration in a Boyden chamber.