Facilitation of in vitro angiogenesis by PTK7 overexpression. (A-B) Endothelial tube formation was compared in shFlt-1, shKDR, and siPTK7 transfection conditions. Cells were seeded at 4 × 104/mL into Matrigel-coated wells of a 48-well plate. A camera-equipped inverted microscope was used for photography. Total tube length (A) and branches (B) were counted at 3 high-magnification images from different areas of each condition; the tube lengths were measured with an image-analysis program (Image Grabbor Version 1.4, Scion Corp; **P < .01 compared with shNeg). All the experiments were performed 3 times with triplicated samples. (C) In vitro tube formation was compared using cells transfected with mock, pPTK7, or PTK7-silenced vascular endothelial cells. Twenty-four hours after transductions, cells were collected and seeded at 4 × 104/mL into Matrigel-coated wells of a 48-well plate. Analysis of tube length was the same method used in panel A. All the experiments were done 3 times with triplicated samples.
