RT Journal Article SR Electronic T1 In Vivo Evaluation of Combined CK2 Inhibition and Irradiation in Human WiDr Tumours JF In Vivo JO In Vivo FD International Institute of Anticancer Research SP 111 OP 117 DO 10.21873/invivo.12238 VO 35 IS 1 A1 FELIX ZWICKER A1 HENRIK HAUSWALD A1 KLAUS-JOSEF WEBER A1 JÜRGEN DEBUS A1 PETER E. HUBER YR 2021 UL http://iv.iiarjournals.org/content/35/1/111.abstract AB 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.