Anti-erbB receptor strategy as a gene therapeutic intervention to improve radiotherapy in malignant human tumours.
OBJECTIVE
We explored and quantified the therapeutic potential of using dominant-negative EGFR transduction with replication-incompetent adenovirus (Ad-EGFR-CD533 or Ad-CD533) as a genetic approach for radiosensitization in different carcinoma and malignant glioma cell lines in vitro and in established tumour xenografts in vivo.


METHODS
The cell lines MDA-MB-231, A-431, U-373 MG, U-87 MG and T47D were used. The ErbB expression profiles were quantified by Western blotting. MAPK immune complex assay measured MAPK activity with or without EGFR-CD533 expression after ionizing radiation. Radiosensitization was determined and quantified in vitro by colony-formation assays, in vivo by use of an ex vivo-in vitro colony-formation assay after intratumoral infusion of the adenoviral vectors expressing EGFR-CD533 or the control LacZ.


RESULTS
Western blotting demonstrated widely varied expression levels of the ErbB receptors in the tested cell lines. Expression of EGFR-CD533 effectively blocked the radiation-induced activation of MAPK, leading to significant radiosensitization in vitro and in vivo.


CONCLUSIONS
The radiation-induced ErbB activation can be effectively modulated by a gene therapeutic approach of over-expressing EGFR-CD533 leading to tumour cell radiosensitization after single and repeated radiation exposures both in vitro and in vivo.
Lammering
G
G
Department of Radiation Oncology, University Hospital Dusseldorf, Germany. Guido.Lammering@uni-duesseldorf.de
Hewit
T H
TH
Valerie
K
K
Lin
P S
PS
Contessa
J N
JN
Schmidt-Ullrich
R K
RK
D000256:Adenoviridae / Q000235:genetics; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000032:analysis / Q000037:antagonists & inhibitors / Q000235:genetics*; D015316:Genetic Therapy; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009369:Neoplasms / Q000737:chemistry / Q000532:radiotherapy*; D011836:Radiation Tolerance; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D020893:Receptor, ErbB-3 / Q000032:analysis; D066247:Receptor, ErbB-4
D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D066247:Receptor, ErbB-4; C587689:ERBB4 protein, human