Contact of sarcoma cells with aligned fibroblasts accelerates their displacement: computer-assisted analysis of tumour cell locomotion in co-culture.

The shape and locomotion of rat sarcoma XC cells on glass, polystyrene, and confluent monolayer cultures of aligned human skin fibroblasts were studied with quantitative, computer-assisted methods. The cell shape depended upon the substratum; the sarcoma cells seeded on fibroblasts assumed polarized shapes. The tumour cells emigrating from aggregates and in sparse cultures showed random locomotion when plated on glass or on the polystyrene surface of tissue culture dishes in isotropic conditions. However, when sarcoma cell aggregates were plated onto underlying aligned fibroblasts, the sarcoma cells showed contact guidance, migrating along the long axes of fibroblasts. Simultaneously, suppression of migration normal to the axis of fibroblasts orientation was observed. The sarcoma cells displaced a few times faster on aligned fibroblasts than under isotropic conditions in control cultures. This fast displacement was found to result from the less frequent cell turnings and straightening of cell trajectories (i.e., from klinokinesis), and not from an acceleration of cell movement and the longer cell tracks (i.e., not from orthokinesis). The presented results support the suggestion of Abercrombie (M. Abercrombie. 1979. Nature (London). 281: 259-262.) that tumour cells may be guided by the underlying normal cells when invading surrounding tissues and forming metastases.