Quantitative assessment of melanoma single-cell motility in vitro

Cell motility is a crucial property of tumor cells during invasion and metastasis. In this study we developed a computer assisted system to measure translocation and stationary motility of single cells and used this procedure to evaluate the influence of cytochalasin A (CA) on single-cell motility parameters of K1735-M2 mouse melanoma cells. The cells were seeded at low density into a microincubator. Time lapse microcinematography was performed every 20 seconds from a high power field to assess stationary motility and every 10 minutes with a screening objective to measure translocation. 1 muMol CA was added to the medium 48 hours before measurement. Calculation of stationary motility was performed by subtraction of subsequent images and the resulting image difference was used for quantitative evaluation. Three different measuring windows were drawn to discriminate between membrane ruffling, intracellular organelle transport and overall stationary motility. For each cell we measured change of density (CD), area of change (AC), perimeter of area of change (PC), area of ruffling (AR), number of ruffling sites (NR), change of intracellular organelles (CIO) and number of changing intracellular organelles (NIO). In order to quantify translocation, the center of gravity of each cell was assessed subsequently and the velocity was calculated by connecting the centers of gravity. CA-treated cells showed a significantly lower stationary motility and membrane ruffling compared to the untreated cells (U-test: p < = 0.01), but there was not significant difference concerning the intracellular organelle transport.(ABSTRACT TRUNCATED AT 250 WORDS)