The ubiquitin-conjugating enzyme UBE2O modulates c-Maf stability and induces myeloma cell apoptosis

Journal of Hematology & Oncology

Depei Wu¹  Xiaowen Tang¹  Yujia Xu²  Zubin Zhang²  Yuanying Zeng²  Xinliang Mao²  Jie Li²  Biyin Cao²  Jiefei Tong³  Michael F. Moran³  Paul Taylor³ 

[1] Department of Hematology, The First Affiliated Hospital of Soochow University;Jiangsu Key Laboratory for Translational Research and Therapeutics of Neuro-Psycho- Diseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University;Program in Molecular Structure and Function, The Hospital for Sick Children, Department of Molecular Genetics, University of Toronto;

关键词: c-Maf;    UBE2O;    Ubiquitin proteasome pathway;    Multiple myeloma;   

DOI  :  10.1186/s13045-017-0499-7

来源: DOAJ

【 摘 要 】

Abstract Background UBE2O is proposed as a ubiquitin-conjugating enzyme, but its function was largely unknown. Methods Mass spectrometry was applied to identify c-Maf ubiquitination-associated proteins. Immunoprecipitation was applied for c-Maf and UBE2O interaction. Immunoblotting was used for Maf protein stability. Luciferase assay was used for c-Maf transcriptional activity. Lentiviral infections were applied for UBE2O function in multiple myeloma (MM) cells. Flow cytometry and nude mice xenografts were applied for MM cell apoptosis and tumor growth assay, respectively. Results UBE2O was found to interact with c-Maf, a critical transcription factor in MM, by the affinity purification/tandem mass spectrometry assay and co-immunoprecipitation assays. Subsequent studies showed that UBE2O mediated c-Maf polyubiquitination and degradation. Moreover, UBE2O downregulated the transcriptional activity of c-Maf and the expression of cyclin D2, a typical gene modulated by c-Maf. DNA microarray revealed that UBE2O was expressed in normal bone marrow cells but downregulated in MGUS, smoldering MM and MM cells, which was confirmed by RT-PCR in primary MM cells, suggesting its potential role in myeloma pathophysiology. When UBE2O was restored, c-Maf protein in MM cells was significantly decreased and MM cells underwent apoptosis. Furthermore, the human MM xenograft in nude mice showed that re-expression of UBE2O delayed the growth of myeloma xenografts in nude mice in association with c-Maf downregulation and activation of the apoptotic pathway. Conclusions UBE2O mediates c-Maf polyubiquitination and degradation, induces MM cell apoptosis, and suppresses myeloma tumor growth, which provides a novel insight in understanding myelomagenesis and UBE2O biology.

【 授权许可】

Unknown