We previously described a novel in vitro culture technique for dedifferentiated human
adult skin melanocytes. Melanocytes cultured in a defined, cholera toxin and PMA free
medium became bipolar, unpigmented, and highly proliferative. Furthermore, TRP-1 and
c-Kit expression disappeared and EGFR receptor and nestin expression were induced
in the cells. Here, we further characterized the phenotype of these dedifferentiated
cells and by comparing them to mature pigmented melanocytes we detected crucial steps
in their phenotype change. Our data suggest that normal adult melanocytes easily dedifferentiate
into pluripotent stem cells given the right environment. This dedifferentiation process
described here for normal melanocyte is very similar to what has been described for
melanoma cells, indicating that phenotype switching driven by environmental factors
is a general characteristic of melanocytes that can occur independent of malignant
transformation.
