Increased expression of the epidermal growth factor receptor in human epidermal keratinocytes after exposure to ionizing radiation

Radiat Res. 1993 Oct;136(1):65-70.


The effect of exposure of human epidermal keratinocytes to ionizing radiation, both in vivo and in vitro, on the expression of the epidermal growth factor receptor (EGF-R) was studied on the protein, mRNA, and functional levels. Quantitative fluorometry of short-term organ cultures incubated with a monoclonal antibody against human EGF-R revealed a dose-dependent increase of EGF-R expression 24 h after irradiation with 4 and 6 Gy, with an additional increase after 48 h. In biopsy specimens from patients undergoing radiation therapy a markedly increased expression could be determined by quantitative fluorometry during radiation therapy which wa still considerably above the baseline level 4 weeks after termination of treatment. Radioligand binding assays demonstrated a 50% increase in 125I-EGF binding to primary keratinocytes and A431 cells, at doses of 1 Gy, with a further increase after 72 and 96 h. Northern blots were performed with total RNA from two human epidermal cell lines (SCLII and A431). In A431 cells, increased EGF-R transcript levels could be detected 48 h after irradiation. In cells of the SCLII cell line, EGF-R expression was not affected by irradiation. These results were confirmed by semiquantitative polymerase chain reaction of primary cultured keratinocytes, demonstrating an increase of transcripts of EGF-R 24 h after irradiation with single doses of 6 Gy. Thus exposure to ionizing radiation leads to an increased expression of functionally intact EGF-R in human keratinocytes, at the protein and mRNA levels, both in vitro and in vivo; we hypothesize that this effect is part of a stress program of epidermal cells in response to ionizing radiation, ensuring rapid repopulation of irradiated areas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Blotting, Northern
  • Cells, Cultured
  • ErbB Receptors / analysis*
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism
  • Fluorometry
  • Humans
  • Infant, Newborn
  • Keratinocytes / chemistry
  • Keratinocytes / radiation effects*
  • Molecular Sequence Data
  • Organ Culture Techniques
  • Polymerase Chain Reaction
  • Radiation, Ionizing


  • ErbB Receptors