2D Matrigel protrusion assays (for floating cultured SCLC cells):
ibidi inserts (80209) were attached to a 12 well plate that was pre-coated with poly-lysine (Sigma P6407, following instruction, 15min coating is enough). After the plate was completely dried, each well could contain up to 2 independent inserts (alternatively, one insert per 24 well). 80 x104 cells in 100μl were then seeded to each chamber of the ibidi insert (cell number varies for cell types, but 80-90% confluence is desired). After 6 hours (or whenever the cells were attached, they should look like a monolayer now), ibidi insert was removed carefully (don’t disrupt the attached cells) and 1ml (can reduce to 0.75ml) of 1:1 matrigel (Corning)-cell culture media mix was gently and slowly added to cover each well and make sure you don’t disrupt the attached cells. Don’t shake the plate strongly. The plate was left in the incubator until the matrigel layer solidified and you could then add 1ml cell culture media to cover the matrigel (prevent drying). To quantify the level of migration, the number of cells that has migrated into the gap were counted in each field at 10x under the scope (potential timepoints: 0, 36, 48, 60, 72, 96h, depends on cell growth rate).