Migration of cells is an initial step during metastasis of cancer. The Oris™ TriCoated Cell Migration Assay measures migration by using cell culture plates equipped with "stoppers": this way seeded cells adhere to the outer rim of a well but are stopped from growing in the center of the well. Upon removal of the stoppers, cells may migrate into the center where they can be stained and measured.
The osteosarcoma cell line U2OS was silenced in different genes known to control cell migration by siRNAs. Cells were kept in medium containing DiI-C16, a molecule which fluoresces if incorporated into membranes, to allow for monitoring of cell migration. Fluorescence measurements after stopper-removal on a BMG LABTECH microplate reader proved the impairment of migration by the knocked-down genes and, hence, the functionality of the Oris™ cell migration assay.