Ras pathway is required for the activation of MMP-2 secretion and for the invasion of src-transformed 3Y1

To search for the signaling pathway critical for tumor invasion, we examine d the effects of dominant negative ras (S17N ras) expression on the activat ion of matrix metalloproteinase-2 (MMP-2) in spc-transformed 3Y1, SR3Y1, un der the control of conditionally inducible promoter. In SR3Y1 clones transf ected with S17N pas, augmented secretion and proteolytic activation of MMP- 2 were dramatically suppressed by S17N Ras expression, while tyrosine phosp horylation of cellular proteins was not suppressed. We found that invasiven ess of SR3Y1 cells assayed by the modified Boyden Chamber method was strong ly suppressed by S17N Ras expression. In contrast, cell morphology reverted partially and glucose uptake remained unchanged by S17N Ras expression. In addition, treatment of SR3Y1 with manumycin A, a potent inhibitor of Ras f arnesyltransferase, strongly suppressed both augmented secretion and proteo lytic activation of MMP-2. Contrary, treatment of SR3Y1 with wortmannin or TPA showed no clear effect on MMP-2 activation. Thus, these results strongl y suggest that Ras-signaling, but neither P13 kinase- nor protein kinase C- signalings, plays a critical role in activation of MMP-2 and, subsequently, in the invasiveness of src-transformed cells.