Regulation of epidermal growth factor receptor expression in normal and transformed keratinocytes

✍ Scribed by M. F. W. Pas; P. M. P. Bergen en Henegouwen; J. Boonstra; M. Ponec

• Publisher: Springer-Verlag
• Year: 1991
• Tongue: English
• Weight: 926 KB
• Volume: 283
• Category: Article
• ISSN: 0340-3696
• DOI: 10.1007/bf00371621

✦ Synopsis

Transformed keratinocytes (SCC-4, SCC-15, SCC-12F2, SVK14) or normal keratinocytes which differ in their differentiation programme were used to study the regulation of EGF-receptor expression. The capacity of the cells to differentiate was modulated by changing the extracellular calcium concentration. We were able to demonstrate that EGF-receptor expression in normal and transformed keratinocytes depends upon the cell type and one or more levels of regulatory control. At the DNA level, EGF-receptor gene amplification occurred in poorly differentiating cells. At the mRNA level, cells showing EGF-receptor gene amplification expressed elevated mRNA and protein levels when cultured under low Ca2+ conditions. Cells not exhibiting EGF-receptor gene amplification showed equal mRNA expression, regardless the Ca2+ concentration in the culture medium. At the protein level, EGF-receptor protein was decreased in cells exhibiting EGF-receptor gene amplification when extracellular Ca2+ was increased (to 1.6 mM) to stimulate differentiation, the decrease in protein being comparable to mRNA expression. Cells not exhibiting EGF-receptor gene amplification showed equal protein expression, regardless of the Ca2+ concentration in the culture medium. Under the same conditions, SV40 transformed keratinocytes showed equal mRNA but elevated protein expression in cells grown under low Ca2+ conditions. At the membrane level, normal keratinocytes and SCC-17F2 cells showed elevated numbers of cell surface exposed EGF-receptors in cells grown under low Ca2+ conditions, but equal mRNA and protein expression.(ABSTRACT TRUNCATED AT 250 WORDS)