S1P-stimulated MT1-MMP–dependent morphogenic differentiation and EC migration proceed through S1P₁ and S1P₃ receptors. (A) Sixteen hours after transfection with MT1-MMP, BAECs were incubated with either S1P₁ and S1P₃ antisense PTOs (S1P₁ and S1P₃ AS) or their respective scrambled controls (S1P₁ and S1P₃ S; 200 nM, 24 h). (i) Cells were plated on Matrigel in serum-free media and stimulated with 1 μM S1P or 10 μM LPA. Original magnification, × 50. (ii) Formation of capillary-like structures was recorded after 6 hours and quantified. Results are expressed as a percentage of capillary-like structure formed by cells treated with S1P₁ and S1P₃ antisense PTOs compared with cells treated with scrambled oligonucleotides controls. Results are the means of 2 independent experiments. (B) Sixteen hours after transfection, BAECs were incubated with the S1P₁ and S1P₃ antisense PTOs or their respective scrambled controls, as described above. (i) Cells were allowed to migrate for 3 hours in media containing either 1 μM S1P or 10 μM. Results are expressed as a percentage of serum factor–induced cell migration of cells treated with S1P₁ and S1P₃ antisense PTOs compared with cells treated with scrambled oligonucleotides controls. Results are the means of 3 independent experiments.