Bowman-Birk protease inhibitor reduces the radiation-induced activation of the EGF receptor and induces tyrosine phosphatase activity.
OBJECTIVE
To investigate the molecular action of the radioprotective Bowman Birk protease inhibitor (BBI) on radiation-induced tyrosine kinase activity.


METHODS
Radiation-induced activation of tyrosine kinases and phosphatases was measured in normal human skin fibroblasts by in vitro kinase assays after pre-incubation with BBI.


RESULTS
Pre-incubation with BBI resulted in a time-dependent block of the radiation-induced activation of tyrosine kinases. Whilst radiation-induced pp60c-Src activity was not modulated due to BBI pre-treatment, activation of epidermal growth factor receptor (EGFR) was inhibited. Additionally, pre-incubation with BBI resulted in enhanced tyrosine specific phosphatase (PTP) activity.


CONCLUSIONS
BBI might exert its radioprotective activity by stabilizing specific tyrosine-phosphatases that interfere with EGFR activation in response to radiation exposure.
Gueven
N
N
Department of Radiotherapy, University of Tuebingen, Germany.
Dittmann
K
K
Mayer
C
C
Rodemann
H P
HP
D004790:Enzyme Induction / Q000187:drug effects / Q000528:radiation effects; D066246:ErbB Receptors / Q000187:drug effects* / Q000528:radiation effects*; D006801:Humans; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis* / Q000187:drug effects / Q000528:radiation effects; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000494:pharmacology*
D011837:Radiation-Protective Agents; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D066246:ErbB Receptors; D017027:Protein Tyrosine Phosphatases