%0 Journal Article %A FELIX ZWICKER %A HENRIK HAUSWALD %A KLAUS-JOSEF WEBER %A JÜRGEN DEBUS %A PETER E. HUBER %T In Vivo Evaluation of Combined CK2 Inhibition and Irradiation in Human WiDr Tumours %D 2021 %R 10.21873/invivo.12238 %J In Vivo %P 111-117 %V 35 %N 1 %X Background/Aim: Casein kinase 2 (CK2) which sustains multiple pro-survival functions in cellular DNA-damage response, is strictly regulated in normal cells but elevated in cancer. CK2 is considered as a potential therapeutic target, and its inhibition has been associated with radiosensitization in mammalian cells in vitro. Here, we investigated potential radiosensitization by CK2 inhibition in vivo. Materials and Methods: The effect of CK2 inhibition in vivo was investigated in human WiDr-xenograft tumours grown subcutaneously on BALB/c nu/nu mice with and without fractionated irradiation. CK2 inhibition was performed using the specific inhibitor tetra-bromobenzotriazole (TBB). Histological examinations included staining for apoptosis and double-strand breaks. Results: Both TBB treatment alone and radiation alone significantly reduced tumour growth, which was reflected by increased apoptosis rates. However, TBB treatment did not boost radiation-induced tumour growth suppression in combined treatment, although the apoptosis rate increased and repair of double-strand breaks was reduced. This was in stark contrast to previous data on in vitro radiosensitization. Conclusion: The absence of radiosensitization by CK2 inhibition should be investigated in different tumour models. %U https://iv.iiarjournals.org/content/invivo/35/1/111.full.pdf