Defined Media for Extended Growth of Human Keratinocytes

The overall goal of Phases I and II is to obtain the benefits of feeder layer cultures of normal hu(NHEK) in a highly defined medium without feeder cells. Feeder layer cultures support robust growth150 population doublings, but the need for serum and a second cell type makes them inconvenient andapplications. Current feeder-free systems support far less doublings and require undefined supplemenThe immediate goal of Phase I is to develop improved assays, to test substances previously reportedNHEK, and to identify roles played by components of the feeder system (feeder cells, serum, etc.) inextending growth of NHEK. We will determine whether serum is needed for feeder effects in an optimizmedium and whether the feeder cells play an active role by supplying growth-promoting substances forpermissive role by neutralizing inhibitory effects and thus unmasking beneficial effects of serum, omuch preliminary purification and characterization of each undefined beneficial activity as time perdevelopment of assays to be used during Phase II for precise biochemical identification of all needecombination into a new highly defined medium for NHEK.