This study aimed to reveal the pathophysiological signalling responsible for radiation-induced sensitization of hepatocytes to TNF-α-mediated apoptosis. IκB was upregulated in irradiated hepatocytes. Administration of IκB antisense oligonucleotides prior to irradiation inhibited occurrence of apoptosis after TNF-α administration. Caspases-8, -9 and -3 activities were increased in irradiated hepatocytes and downregulation of apoptosis by IκB antisense oligonucleotides was mediated by suppression of caspases-9 and -3 activation but not of caspase-8 activation, suggesting that radiation-induced sensitization of hepatocytes to TNF-α-mediated apoptosis additionally requires changes upstream of caspase-8 activation. Herein, upregulation of FLIP may play a crucial role. Cleavage of bid, upregulation of bax, downregulation of bcl-2 and release of cytochrome c after TNF-α-administration depend on radiation-induced upregulation of IκB, thus demonstrating an apoptosis permitting effect of IκB. © 2008 The Author(s).
CITATION STYLE
Gürleyen, H., Christiansen, H., Tello, K., Dudas, J., Hermann, R. M., Rave-Fränk, M., … Saile, B. (2009). Irradiation leads to sensitization of hepatocytes to TNF-α-mediated apoptosis by upregulation of IκB expression. Radiation and Environmental Biophysics, 48(1), 85–94. https://doi.org/10.1007/s00411-008-0200-1
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