Adenovirus-mediated overexpression of dominant negative epidermal growth factor receptor-CD533 as a gene therapeutic approach radiosensitizes human carcinoma and malignant glioma cells

Int J Radiat Oncol Biol Phys. 2001 Nov 1;51(3):775-84. doi: 10.1016/s0360-3016(01)01714-x.


Purpose: Epidermal growth factor receptor (EGFR) and other members of the ErbB family of receptor tyrosine kinases (RTK) mediate autocrine growth regulation in a wide spectrum of human tumor cells. We have previously demonstrated that in stably transfected mammary carcinoma cells a dominant negative (DN) mutant of EGFR, EGFR-CD533 is a potent inhibitor of EGFR and its cytoprotective signaling after exposure to ionizing radiation. In the present study, we further investigate the capacity of a genetic approach, using replication-incompetent adenovirus (Ad)-mediated transfer of EGFR-CD533 (Ad-EGFR-CD533), to enhance the radiosensitivity in vitro of four cell lines representative of three major cancer phenotypes.

Methods and materials: The cell lines MDA-MB-231 and T-47D mammary carcinoma, A-431 squamous carcinoma, and U-373 MG malignant glioma cells were used. The ErbB expression profiles and the EGFR tyrosine phosphorylation (Tyr-P) levels following irradiation were quantified by Western blotting. The relative radiosensitivities of tumor cells were assessed by standard colony formation assays after infection with control vector (Ad-LacZ) or Ad-EGFR-CD533.

Results: The expression profiles demonstrated varying levels of EGFR, ErbB2, ErbB3, and ErbB4 expression. The overexpression of EGFR-CD533 after infection with Ad-EGFR-CD533 completely inhibited the radiation-induced stimulation of EGFR Tyr-P relative to the immediate 2.4- to 3.1-fold increases in EGFR Tyr-P in control infected cells (Ad-LacZ). Ad-EGFR-CD533-infected cells demonstrated significant (p < 0.001) radiosensitization over a range of radiation doses (1-8 Gy), yielding dose-enhancement ratios (DER) between 1.4 and 1.7. This radiosensitization was maintained under conditions of repeated radiation exposures, using 3 x 2 Gy, yielding DERs of 1.6 and 1.7 for MDA-MB-231 and U-373 cells, respectively.

Conclusions: Overexpression of EGFR-CD533 significantly sensitizes human carcinoma and glioma cells to single and repeated radiation exposures irrespective of their ErbB expression levels. Therefore, transduction of human tumor cells with EGFR-CD533 holds promise as a gene therapeutic approach for the radiosensitization of neoplastic cells that are growth-regulated by EGFR or other ErbB receptors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenoviridae / genetics
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / therapy
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / metabolism*
  • Carcinoma, Squamous Cell / therapy
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism*
  • Gene Expression Regulation, Neoplastic
  • Genes, Dominant
  • Genetic Therapy / methods*
  • Glioma / genetics
  • Glioma / metabolism*
  • Glioma / therapy
  • Humans
  • Phosphorylation
  • Radiation Tolerance
  • Receptor, ErbB-2 / genetics
  • Receptor, ErbB-2 / metabolism*
  • Receptor, ErbB-3 / genetics
  • Receptor, ErbB-3 / metabolism*
  • Receptor, ErbB-4
  • Tumor Cells, Cultured / radiation effects
  • Tumor Stem Cell Assay


  • ERBB4 protein, human
  • ErbB Receptors
  • Receptor, ErbB-2
  • Receptor, ErbB-3
  • Receptor, ErbB-4