Growth of normal oral keratinocytes and squamous cell carcinoma cells in a novel protein-free defined medium.

A novel protein-free synthetic medium was developed for the culture of normal human oral keratinocytes. This medium, designated PFM-7, supports the serial cultivation of primary or secondary normal oral keratinocytes in protein-free, chemically defined conditions. Normal oral keratinocytes in PFM-7 exhibited nearly equal growth in mass culture without noticeable changes in morphology, response to added growth factors, or gene expression of growth factors and their receptors, compared to cells in Keratinocyte-SFM containing epidermal growth factor and bovine pituitary extract. Furthermore, PFM-7 supported the serial subcultivation of human squamous cell carcinoma cells and enabled both normal and malignant oral squamous cells derived from the same patient to grow under the same protein-free defined conditions. These results indicate that PFM-7 can be used for precise investigations of growth mechanisms, cell products, and gene expression associated with carcinogenesis of human epidermal cells.