Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, 85721, USA.
Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, 85721, USA; National & Local Joint Engineering Research Center of Biodiagnosis and Biotherapy, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; International Joint Research Center on Cell Stress and Disease Diagnosis and Therapy, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Redox Biol. 2023 Sep;65:102839. doi: 10.1016/j.redox.2023.102839. Epub 2023 Aug 9.
p97 is a ubiquitin-targeted ATP-dependent segregase that regulates proteostasis, in addition to a variety of other cellular functions. Previously, we demonstrated that p97 negatively regulates NRF2 by extracting ubiquitylated NRF2 from the KEAP1-CUL3-RBX1 E3 ubiquitin ligase complex, facilitating proteasomal destruction. In the current study, we identified p97 as an NRF2-target gene that contains a functional ARE, indicating the presence of an NRF2-p97-NRF2 negative feedback loop that maintains redox homeostasis. Using CRISPR/Cas9 genome editing, we generated endogenous p97 ARE-mutated BEAS-2B cell lines. These p97 ARE-mutated cell lines exhibit altered expression of p97 and NRF2, as well as a compromised response to NRF2 inducers. Importantly, we also found a positive correlation between NRF2 activation and p97 expression in human cancer patients. Finally, using chronic arsenic-transformed cell lines, we demonstrated a synergistic effect of NRF2 and p97 inhibition in killing cancer cells with high NRF2 and p97 expression. Our study suggests dual upregulation of NRF2 and p97 occurs in certain types of cancers, suggesting that inhibition of both NRF2 and p97 could be a promising treatment strategy for stratified cancer patients.
p97 是一种泛素靶向的 ATP 依赖性分拣酶，除了各种其他细胞功能外，还调节蛋白质稳态。此前，我们证明 p97 通过从 KEAP1-CUL3-RBX1 E3 泛素连接酶复合物中提取泛素化的 NRF2，负调控 NRF2，促进蛋白酶体降解。在本研究中，我们确定 p97 是 NRF2 的靶基因，其中包含一个功能性 ARE，表明存在 NRF2-p97-NRF2 负反馈回路，以维持氧化还原平衡。使用 CRISPR/Cas9 基因组编辑，我们生成了内源性 p97 ARE 突变的 BEAS-2B 细胞系。这些 p97 ARE 突变的细胞系表现出 p97 和 NRF2 的表达改变，以及对 NRF2 诱导剂的反应受损。重要的是，我们还在人类癌症患者中发现了 NRF2 激活与 p97 表达之间的正相关。最后，使用慢性砷转化细胞系，我们证明了 NRF2 和 p97 抑制在杀死高表达 NRF2 和 p97 的癌细胞方面具有协同作用。我们的研究表明，某些类型的癌症中存在 NRF2 和 p97 的双重上调，这表明抑制 NRF2 和 p97 可能是分层癌症患者的一种有前途的治疗策略。
