Identification and characterization of autocrine‐motility‐factor‐like activity in oral squamous‐cell‐carcinoma cells

A human oral squamous‐cell‐carcinoma cell line, HOC313, was found to produce a factor which stimulates cell motility in an autocrine manner. The motility factor of HOC313 cells also promoted the locomotory activity of B16 murine melanoma cells reported to be sensitive to autocrine motility factor (AMF). HOC313 cells were found to express a large amount of AMF receptor mRNA. In addition, the cell motility activity of HOC313 cells was completely blocked by pertussis toxin, a known inhibitor of AMF activity, suggesting that the motility factor of HOC313 cells may be AMF or a closely related factor. Immunocytochemical analysis has revealed that the AMF‐like factor of HOC313 cells diminishes the cell‐surface expression of adhesive molecule E‐cadherin. These results suggest that down‐regulation of E‐cadherin may be involved in the cell‐motility activity induced by the AMF‐like factor of HOC313 cells.