FIG. 1.

Gas6 is a growth factor for C57MG cells. (A) Analysis of Gas6 growth-promoting effect on different cell lines. Cells representing REF, rat SMC, IMR90, SA0S, MCF7, NIH 3T3, and C57MG were seeded at 10⁴ cells per cm² in 6-cm petri dishes. After 24 h from plating in 10% FCS, 400 ng of recombinant Gas6/ml was added to the medium for 3 days. After this time, MTT was added to the medium to monitor the cell number for 4 h. All the experiments were performed in duplicate at least three times. The lower panel shows the morphology of Gemsa-stained Gas6-treated C57MG cells. (B) Analysis of C57MG growth rate in the presence of Gas6. C57MG cells were similarly seeded in 6-cm-diameter petri dishes and labeled with MTT on days 1, 2, 3, and 4 after seeding in the presence or absence of 400 ng of Gas6/ml in the culture medium. (C) Analysis of Gas6-induced increase of C57MG cell number. Cells were seeded as described above at half concentration, and the increase in cell number was evaluated after 1, 2, 3, and 4 days of culture in the presence or absence of 400 ng of Gas6/ml in complete medium. After trypsinization the cells were counted using a bright-light hemacytometer Neubauer chamber (Sigma). All the experiments shown were carried out in duplicate.