Characteristics of the bone-tumor cocultures. A. Schematic depicting the placement of the physical and biological components of the coculture system. The stainless steel ring encircles the outer perimeter of each well in a 6-well plate, with a wire protruding from one side into the center (1) that immobilizes a neonatal femur (2). Tumor cells are plated as a bead on the opposite side of the well shown as a shaded circle (3). B. Femur is shown in place under the wire with the proximal end (*), the distal end (#) and the diaphysis (arrowheads) visible, as well as the dark marrow cavity. C & D. One of the tumor cell lines used in the studies, NCTC 2472 fibrosarcoma cells, are pictured as plated, under brightfield (C) as well as under epifluorescence (D) showing expression of the DSR protein. Bars shown equal 150 μm.