CK2α/CSNK2A1 Induces Resistance to Doxorubicin Through SIRT6 Mediated Activation of the DNA Damage Repair Pathway
Abstract BackgroundCK2α/CSNK2A1 is involved in cancer progression by phosphorylating various signaling molecules. Considering the role of CSNK2A1 in cancer progression and phosphorylation of SIRT6 and the role of SIRT6 in chemoresistance through the DNA damage repair pathway, CSNK2A1 and SIRT6 might be involved in resistance to the conventional anti-cancer therapies.MethodsWe evaluated the expression of CSNK2A1 in the 37 osteosarcoma patients and investigated the effects of CSNK2A1 and phosphorylation of SIRT6 on Ser338 on the resistance to the anti-cancer effects of doxorubicin. Results Higher expression of CSNK2A1 predicted shorter overall survival and relapse-free survival in both general osteosarcoma patients and sub-population of patients who received postoperative chemotherapies. U2OS and KHOS/NP osteosarcoma cells with induced overexpression of CSNK2A1 were resistant to cytotoxic effects of doxorubicin, and knock-down of CSNK2A1 potentiated the cytotoxic effects of doxorubicin. CSNK2A1 overexpression-mediated resistance to doxorubicin was associated with SIRT6 phosphorylation and induction of the DNA damage repair pathway molecules ATM and Chk2. CSNK2A1 and SIRT6 mediated resistance to doxorubicin in vivo was attenuated via mutation of SIRT6 at the Ser338 phosphorylation site. Emodin, a CSNK2A1 inhibitor, potentiated the cytotoxic effects of doxorubicin in osteosarcoma cells in vitro. ConclusionsThis study demonstrates that the expression of CSNK2A1 might be used as a prognostic indicator of osteosarcoma. In addition, it suggests that CSNK2A1 induces resistance to doxorubicin through phosphorylation of SIRT6-mediated activation of the DNA damage repair pathway. Therefore, blocking the CSNK2A1-SIRT6-DNA damage repair pathway might be a new therapeutic stratagem for the poor prognostic subgroup of osteosarcomas with high expression of CSNK2A1.