Article
作者: Wasik, Mariusz ; Nieborowska-Skorska, Margaret ; Valent, Peter ; Caron, Marie-Christine ; Masson, Jean-Yves ; Le, Bac Viet ; Haydar, Zayd ; Ghosh, Jayashri ; Podszywalow-Bartnicka, Paulina ; Bellacosa, Alfonso ; Huntly, Brian J P ; Toma, Monika M ; Nejati, Reza ; Challen, Grant A ; Atkins, Jessica ; Gupta, Gaorav P ; Kukuyan, Anna-Mariya ; Chandramouly, Gurushankar ; Vekariya, Umeshkumar ; Piwocka, Katarzyna ; Vaughan-Williams, Elaine ; Walsh, Martin ; Vassiliou, George S ; Skorski, Tomasz ; Hadzijusufovic, Emir ; Pomerantz, Richard ; Ziolkowska, Sylwia ; Gozdecka, Malgorzata
Myeloid malignancies carrying somatic DNMT3A mutations (DNMT3Amut) are refractory to standard therapy. DNMT3Amut leukemia cells accumulate toxic DNA double-strand breaks (DSBs) and stalled replication forks, rendering them dependent on DNA damage response (DDR). We report here that DNA polymerase theta (Polθ), a key element in DSB repair by end-joining (Polθ-mediated end-joining [TMEJ]) and in fork restarting, promotes survival and proliferation of DNMT3Amut leukemia cells. Polθ is overexpressed in DNMT3Amut leukemia cells due to abrogation of PARP1 PARylation-dependent UBE2O E3 ligase-mediated ubiquitination and proteasomal degradation of Polθ. In addition, PARP1-mediated recruitment of the SMARCAD1-MSH2/MSH3 repressive complex to DSBs is diminished in DNMT3Amut leukemia cells, which facilitates association of Polθ with DNA damage. Polθ inhibitors enhance the anti-leukemic effects of standard drugs such as FLT3 kinase inhibitor quizartinib, cytarabine ± doxorubicin, and etoposide in vitro and in mice with DNMT3Amut leukemia. Altogether, Polθ is an attractive target in DNMT3Amut hematological malignancies.