In vitro junction and tubule formation assay. Control and scNT-N-derived PUVECs formed an extensive capillary-like network 24 hr after plating onto Matrigel (a and b), while scNT-MUC PUVECs formed a truncated and abnormal network (c). Cells were viewed by phase-contrast microscopy. Magnification, 40×. Tubule length was measured under a microscope and then average tubule length was plotted. The data were expressed as the mean value of tubule length measured in individual control, scNT-N and scN-MUC with at least 3 independent experiments. * P < 0.05, ** P < 0.01.