Modulation of fibroblast motility by a cytosolic extract of Cyanobacteria

Proliferation and migratory behavior of L929 murine fibroblasts were shown to be modified in the presence of a cytosolic extract of Phormidium sp. (Cyanobacteria). The addition of Phormidium extract to the growth medium (Dulbecco's modified Eagle's medium) supplemented with 0.5% newborn calf serum increased cell proliferation. The effect was shown to be cell line specific. A quantitative analysis performed according to De Laat, Tertoolen, and Bluemink (1981, Eur. J. Cell Biol., 23, 273-279), showed that Phormidium extract was a potential aggregative effector for fibroblasts. Heating (100 degrees C, 4 min) inactivated the clustering effect of the extract, but the effect on cell proliferation was retained. A video analysis of cells after divisions showed that the extract activated cell migration in the same way as 5% serum did during the first 24 h of treatment. Between 24 and 48 h of treatment, cell migration in the presence of the extract was inhibited when compared to migration in 0.5 or 5% serum. We have shown that Phormidium extract may contain two or three kinds of effectors which acted as exogenous growth factors (allowing attachment and proliferation) and as modulator(s) of the cell migratory behavior (activator of migration in early times of the growth and inhibitor later).