Effect of Nck2 on human primary melanoma cell derived spheroid in type 1 collagen and invasion. (A) Spheroids of human primary WM278 melanoma cells overexpressing GFP (C2) or GFP-Nck2 (N14) and human metastatic WM1617 melanoma cells embedded in 3D type I collagen gel were analyzed for morphology and invading cells. Pictures (10X) were taken at time 0 and after 48 hours of culture. White bars = 200 μm or 50 μm for zoomed pictures. (B) Invasion of human primary WM278 melanoma cells overexpressing GFP (C2) or GFP-Nck2 (N14) was evaluated using Matrigel™ transwell assays. Results are expressed as the mean of invaded cells ± SD from one experiment performed in triplicate. * p < 0.01 vs C2 using Student's t-test. Similar results were observed in three independent experiments.