The Role of MEK and Antizyme in Keratinocyte Stem Cell Expansion and Differentiation

The study used transgenic mice to explore the role of MEK and Antizyme (AZ) in skin tumorigenesis and keratinocyte differentiation. Mice overexpressing MEK showed increased epidermal hyperplasia, tumor development, and expansion of epidermal stem cells, with decreased keratinocyte differentiation. However, co-expression of AZ reduced tumor development and normalized the number of transient amplifying (TA) cells and stem cells, counteracting the effects of MEK. AZ also restored normal levels of differentiation markers in keratinocytes, suggesting that AZ can mitigate MEK-induced suppression of differentiation. The findings indicated that ornithine decarboxylase (ODC) and polyamines played crucial roles in regulating epidermal stem cell expansion and keratinocyte progenitor cell differentiation.