Figure 1.

Spheroids of self-renewing cells from established human cell lines of squamous carcinomas and adenocarcinomas of the cervix. A, Morphology of cells cultured in anchorage-independent conditions as non-adherent clusters one week after plating HeLa (a), SiHa (b), Ca Ski (c), and C-4 I (d) cells. Magnification is 10X, size bar = 100 μm. B, Serial photographs during culture demonstrated progressive increase diameter at 4 (a), 8 (b), 12 (c) and 16 days (d). Magnification is 10X, size bar = 100 μm. C, Sphere-forming efficiency (SFE) of spheroid cells on serial passage from first to fifth generation (G1-G5). Cells were plated at a density of 100 cells/well in 200-μl of serum-free medium (SFM), spheres were counted weekly. Bar graph represents the SFE mean calculated by counting the number of spheres formed in a given well and dividing by the total number of cells seeded in the well, represented as a percentage. Error bars represent standard deviation (SD) (n = 3); * p < 0.05 and ** p < 0.005