Figure 1
Cell aggregation correlated with cell growth in suspension culture and in soft agar. A, Upper panel: Cell aggregation in polyHEMA-coated dishes (× 100). H1792, H460, A549, SK-LU-1, MDCK, and HBE cells were cultured on 60-mm polyHEMA-coated dishes (2.5 × 105/dish) for 8 hours and photographed. Lower panel: Colony-formation of cells in soft agar. 4 × 104 cells were seeded into 60 mm soft agar plates and incubated for 2 weeks and photographed. B, Correlation between cell aggregation and soft agar growth. The numbers of clonies formed in soft agar after 14 d incubation were plotted against the mean numbers of cell aggregates per 10 fields formed in polyHEMA-coated dishes. Pearson's correlation coefficient was used. N: Number C, Proliferation of tumor cells and normal cells in regular (left) and polyHEMA-coated (right) dishes. Cells as indicated from regular cell culture dishes were plated into regular or polyHEMA-coated dishes (4 × 104/dish) for 1, 2, 3, 4 or 5 d. At the end of each incubation viable cells were counted using trypan blue exclusion. D, Cell aggregation promoted tumor cell proliferation in suspension cultures. 2.5 × 104 tumor cells as indicated from regular cell culture dishes were plated into polyHEMA-coated or methyl cellulose plates for 1, 2, or 3 d. At the end of each incubation viable cells were counted using trypan blue exclusion. Data from at least three separate experiments were analyzed using Student's t test. "***": P < 0.001. S: Suspension culture in polyHEMA-coated dishes MS: Suspension culture in methyl cellulose dishes.