FIGURE 2.

Halo culture system. A: MUM2B metastatic melanoma cells were constrained on plastic culture dishes by a 3-mm-diameter cloning ring. B: Ten days after initial plating, the MUM2B cells did not form vasculogenic mimicry patterns and expanded from the initial constrained area to fill the well. C: MUM2B cells were seeded on a raft of Matrigel until vasculogenic mimicry patterns formed. A 3-mm-diameter punch was taken from the seeded raft and grafted onto a virgin recipient bed of Matrigel. D: Ten days after the graft in C was placed, MUM2B melanoma cells migrated only a short distance onto the recipient Matrigel bed. E: Higher magnification of the edge of the graft illustrated in D. The melanoma cells in the recipient bed are elongated in contrast to the normal epithelioid shape of MUM2B cells. The MUM2B cells formed reticulated looping patterns adjacent to the graft. Note that the cells formed patterns and retracted back toward the graft: impressions of the vacant patterns are visible in the top right area of the picture, just below and to the left of the label. Original magnifications: ×50 (A–D); ×200 (E).