Abstract: Genetically engineered endothelial cells which exhibit enhanced cell migration and enhanced urokinase-type plasminogen activator (u-PA) activity are provided. The cells are modified by incorporation of the coding sequence for the c-src gene so that the cells express elevated levels of the tyrosine kinase protein, pp60.sup.c-src. The C-src gene is a naturally occurring gene which appears to be present in all animal species and is highly conserved. Because of their enhanced migration rates, the modified cells can be used to efficiently seed denuded segments of vessels or natural or synthetic grafts prior to implantation. Because of their enhanced u-PA activity, the cells can reduce the probability of thrombus formation at sites of vessel damage, such as that produced during such surgical procedures as coronary angioplasty and vessel reconstruction with grafts, stents, or the like.