Quantification of Cell Motility: Gold Colloidal Phagokinetic Track Assay and Wound Healing Assay

Cellular migration is an integral aspect in response to extracellular stimuli, which is fundamental to numerous biological processes such as embryogenesis, inflammation, wound healing, tissue regeneration, and tumor invasion and metastasis (1 ,2 ). Abundant studies centered on the identification and characterization of factors that regulate and direct cell movement have shown that host serum components and extracellular matrix breakdown products exert a chemotactic effect on various tumor cells (3 ) and that basement membrane and extracellular matrix components promote cellular haptotaxis (4 ). Furthermore, host growth factors influence recipient cells by modulating growth and motility independently or in a coordinated manner (2 ). Moreover, cellular migration in vitro has been reported to be correlated with tumor invasion and metastasis in vivo. A group of motility factors has been described, the primary function of which is thought to be the regulation of cellular kinesis. Motility factors have been originally distinguished by their ability to induce the random (chemoki-netic) and directional (chemotactic) migration of the cells (5 ). Therefore, quantitating the cell motility is one of the most important clues to comprehend the cellular characteristics of malignancy and/or the effect and activities of motility inducing properties. Gold colloidal method was invented to measure the random motility (chemokinesis) by Albrecht-Buehler, in which area of phagokinetic track cleared by a single cell is measured (6 ). The Boyden chamber method, described in Chapter 5 by Brown and Bicknell, was invented to quantitate the directional motility (chemotaxis) and was modified in various ways to