NF-kB and poly (ADP-ribose) polymerase 1 form a positive feedback loop that regulates DNA repair in acute myeloid leukemia cells

Abstract

NF-kB mediates acquired resistance in acute myeloid leukemia (AML) cells treated with DNA-damaging agents. Because DNA repair is the major molecular shift that alters sensitivity to DNA-damaging agents, we explored whether activation of the NF-kB pathway promotes AML cell survival by regulating DNA repair after chemotherapy. Our results showed that RELA, an important subunit of NF-kB, regulated DNA repair by binding to the promoter region of the PARP1 gene and affecting PARP1 gene transcription. Conversely, PARP1 knockdown reduced NF-kB activity, indicating that NF-kB and PARP1 create a positive feedback loop in DNA repair. Simultaneous treatment with the NF-kB inhibitor BMS-345541 and the PARP1 inhibitor olaparib resulted in robust killing of AML cells. This dual inhibition significantly suppressed tumor growth and extended survival times in xenograft tumor models. Implications: RELA and PARP1 form a positive feedback loop to regulate DNA damage repair, simultaneous inhibition of NF-kB and PARP1 increases the antileukemic efficacy of daunorubicin in vitro and in vivo, broadening the use of PARP1 inhibitors.