The increase in cytosolic levels of protein kinase C precedes the growth factor requirements during the transition stem cells to differentiated progeny in the MCF‐7 breast tumor cells.

Abstract

The expression of regulatory genes within the context of a differentiation program can have profound long-term consequences in tissues with permanent renewing populations. The breast tumor cell line MCF-7 retains in culture some of the characteristics of a unidirectional differentiation pathway. We show that the cytosolic activity of the regulatory enzyme protein kinase C (PKC) precedes and continues the sequence of maturation in pre-differentiated subpopulations derived from a stem cell fraction. However, the activity declines in the most differentiated, postmitotic fraction. These results indicate that PKC may be considered among the regulatory genes in MCF-7 cells that specify maturation of the stem cell progeny.