Figure 2.

Effects of human fibroblast-derived diffusible factors on growth and invasiveness of in vitro neoplastic oral epithelium reconstructed from partially transformed keratinocytes. Neoplastic oral epithelium was reconstructed by growing DOK cells on top of simple collagen gel (A), human fibroblast-containing matrix (B), or on sandwich models with a bottom layer of human fibroblast-containing matrix and an intermediate layer of simple collagen gel (C). Conditioned medium from parallel organotypic co-cultures of DOK on human fibroblast-containing matrices was added at day 3 of co-culture (D). H&E staining is shown (A–D). E: Epithelial growth (total epithelial thickness and cell proliferation index) and invasion (depth and area of invasion) were assessed. Data represent mean ± SEM of six different experiments. ^¤Statistically significant difference when compared with DOK cultures on human fibroblast-containing matrix; ^#statistically significant difference when compared with DOK cultures on simple collagen gels. Scale bar, 50 μm.