A Cytosolic ATM/NEMO/RIP1 Complex Recruits TAK1 To Mediate the NF-κB and p38 Mitogen-Activated Protein Kinase (MAPK)/MAPK-Activated Protein 2 Responses to DNA Damage

Abstract

In multiple tumor types, activation of the transcription factor NF-B increases the resistance of tumor cells to anticancer therapies and contributes to tumor progression. Genotoxic stress induced by chemotherapy or radiation therapy triggers the ATM-dependent translocation of NF-B essential modifier (NEMO), also designated I B kinase ␥ (IKK␥), from the nucleus to the cytosol, resulting in I B kinase activation by mechanisms not yet fully understood. RIP1 has been implicated in this response and found to be modified in cells with damaged DNA; however, the nature of the RIP1 modification and its precise role in the pathway remain unclear. Here, we show that DNA damage stimulates the formation of a cytosolic complex containing ATM, NEMO (IKK␥), RIP1, and TAK1. We find that RIP1 is modified by SUMO-1 and ubiquitin in response to DNA damage and demonstrate that modified RIP1 is required for NF-B activation and tumor cell survival. We show that ATM activates TAK1 in a manner dependent on RIP1 and NEMO. We also reveal TAK1 as a central mediator of the alternative DNA damage response pathway mediated by the p38 mitogen-activated protein kinase (MAPK)/MAPK-activated protein 2 (MAPKAP-2) kinases. These findings have translational implications and reveal RIP1 and TAK1 as potential therapeutic targets in chemoresistance.The DNA damage response activates cell cycle checkpoint and survival pathways that function to prevent DNA replication until damaged DNA is repaired. These pathways include the well-characterized ATM (ataxia telangiectasia mutated)/ CHK2 and ATR (ataxia telangiectasia and Rad-3 related)/ CHK1 pathways and the more recently identified ATM/ ATR/p38 mitogen-activated protein kinase (MAPK)/MAPKactivated protein 2 (MAPKAP-2; hereinafter called MK2) checkpoint that is active in p53-deficient tumor cells (15,19). The transcription factor NF-B regulates apoptosis induced by genotoxic stress and is an attractive therapeutic target in tumor cells whose response to DNA-damaging agents is impaired due to compromised p53 function. Moreover, constitutive NF-B activity is a hallmark of several cancers, and mutations in NF-B pathway components have been associated with the activated B cell (ABC) subtype of diffuse large B cell lymphoma (DLBCL), breast cancer, and multiple myeloma (3, 6). Thus, the inclusion of NF-B inhibitors in cancer therapy could have antioncogenic activities as well as augment the tumor chemotherapeutic response.NF-B is normally held in the cytoplasm in an inactive form bound to inhibitor proteins, such as I B␣. Diverse stimuli, such as infection, proinflammatory cytokine production, or treatment with agents that induce DNA damage elicit NF-B-mediated transcriptional activity by activating the cytosolic I B kinase (IKK) complex, consisting of IKK␣ and IKK␤ and a regulatory subunit designated IKK␥ or NF-B essential modifier (NEMO) (hereinafter referred to as NEMO). IKK activation results in I B␣ phosphorylation, ubiquitination, and subsequent degradation. The NF-B (p65/p50) heterodimer is then free to en...

Receptor-interacting Protein 1 Increases Chemoresistance by Maintaining Inhibitor of Apoptosis Protein Levels and Reducing Reactive Oxygen Species through a microRNA-146a-mediated Catalase Pathway

“…RIP1 knockdown significantly increased cisplatin-induced apoptosis and cytotoxicity in human lung cancer cells. These results are in agreement with the observations that RIP1 knockout mouse embryonic fibroblast cells are more susceptible to doxorubicin-induced cytotoxicity (29). However, a prodeath role for RIP1 has also been reported.…”

PACS-2 mediates the ATM and NF-κB-dependent induction of anti-apoptotic Bcl-xL in response to DNA damage

“…[17][18][19]43 Following DNA damage, a small pool of nuclear ATM translocates to the cytoplasm where it initiates formation of signalosome complexes required for IκK-mediated NF-κB activation. 16,28,31,43 However, little is known about the mechanism of the ATM 'nucleus-to-cytoplasm' translocation and its cytoplasmic trafficking to drive NF-κB activation in response to DNA damage.…”

“…16 Current models suggest that DNA damage triggers activation of ATM in the nucleus followed by the translocation of this DNA repair kinase to the cytoplasm where it supports IκK activation. [16][17][18][19] However, little is known about the cell machinery involved in the 'nucleus-to-cytoplasm' translocation and cytoplasmic trafficking of ATM that drives DNA damage-triggered NF-κB activation.…”

Contribution of RIP3 and MLKL to immunogenic cell death signaling in cancer chemotherapy

“…41 In that paper, RIP3 activation by dimerization was shown to lead to the activation of RIP1, which in turn stimulated an NF-kB-mediated transcriptional program that contributed to the immunogenicity of dying cells. 41 Anthracyclines potently induce the NF-kB pathway in a RIP1-dependent fashion, 42,43 suggesting that this pathway may contribute to chemotherapy-elicited ICD as well.…”