iProXProteomicsJie ZhaoHomo Sapienshttp://www.iprox.org/page/project.html?id=IPX0004756000prozhaojie@126.comShanghai Jiao Tong University School of MedicineiProXChemoresistance is the main obstacle in osteosarcoma (OS) treatment; however, the underlying mechanism remains unclear. In this study, it is discovered that DDRGK domain-containing protein 1 (DDRGK1) plays a fundamental role in chemoresistance induced in OS. Bioinformatic and tissue analyses indicate that higher expression of DDRGK1 correlates with advanced tumor stage and poor clinical prognosis of OS. Quantitative proteomic analyses suggest that DDRGK1 plays a critical role in mitochondrial oxidative phosphorylation. DDRGK1 knockout trigger the accumulation of reactive oxygen species (ROS) and attenuate the stability of nuclear factor erythroid-2-related factor 2 (NRF2), a major antioxidant response element. Furthermore, DDRGK1 inhibits ubiquitin-proteasome-mediated degradation of NRF2 via competitive binding to the Kelch-like ECH-associated protein 1 (KEAP1) protein, which recruits NRF2 to CULLIN(CUL3). DDRGK1 knockout attenuates NRF2 stability, contributing to ROS accumulation, which promotes apoptosis and enhanced chemosensitivity to doxorubicin (DOX) and etoposide in cancer cells. Indeed, DDRGK1 knockout significantly enhances osteosarcoma chemosensitivity to DOX in vivo. The combination of DDRGK1 knockdown and DOX treatment provides a promising new avenue for the effective treatment of OS.DDRGK1 Enhances Osteosarcoma Chemoresistance via Inhibiting KEAP1-Mediated NRF2 Ubiquitination.Wang Xin X, Zhou Tangjun T, Yang Xiao X, Cao Xiankun X, Jin Gu G, Zhang Pu P, Guo Jiadong J, Rong Kewei K, Li Baixing B, Hu Yibin Y, Liu Kexin K, Ma Peixiang P, Qin An A, Zhao Jie JfalseQuantitative proteomic analysis reveals novel function of DDRGK1 in osteosarcomaDDRGK1 is identified as a target of ufymaltion, while its function in tumor is still largely unknown and even controversial according to recent study. To invesgate the role of DDRGK1 in osteosarcoma, DDRGK1 gene was knockout in 143B cells by CRISPR/cas9, and recombinant DDRGK1 protein was added in the cell culture medium and stimulated for 24h. whole cell protein extracts were harvested and TMT-labelled proteomics analysis was performed.Thu Jul 21 00:00:00 BST 2022PXD035473960636965071