The ubiquitin-conjugating enzyme UBE2O modulates c-Maf stability and induces myeloma cell apoptosis.
The ubiquitin-conjugating enzyme UBE2O modulates c-Maf stability and induces myeloma cell apoptosis.
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泛素结合酶 UBE2O 调节 c-Maf 稳定性并诱导骨髓瘤细胞凋亡
DOI：
10.1186/s13045-017-0499-7
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发表时间：
2017-07-03
影响因子：
28.5
通讯作者：
Mao X
中科院分区：
文献类型：
--
作者：
Xu Y;Zhang Z;Li J;Tong J;Cao B;Taylor P;Tang X;Wu D;Moran MF;Zeng Y;Mao X
背景UBE 2 O被认为是一种泛素结合酶，但其功能尚不清楚。免疫沉淀法用于c-Maf和UBE 2 O相互作用。免疫印迹用于Maf蛋白稳定性。荧光素酶测定用于c-Maf转录活性。将慢病毒感染应用于多发性骨髓瘤（MM）细胞中的UBE 20功能。结果亲和纯化/串联质谱法和免疫共沉淀法检测到UBE 2 O与MM中的关键转录因子c-Maf相互作用。随后的研究表明UBE 2 O介导c-Maf的多聚泛素化和降解。UBE 2 O还下调了c-Maf的转录活性和c-Maf调控的典型基因cyclin D2的表达。基因芯片显示UBE 2 O在正常骨髓细胞中表达，在MGUS、冒烟型MM和MM细胞中表达下调，在原代MM细胞中表达下调，提示UBE 2 O可能参与骨髓瘤的病理生理过程。当UBE 2 O恢复时，MM细胞中的c-Maf蛋白明显减少，MM细胞发生凋亡。结论UBE 2 O介导c-Maf多聚泛素化和降解，诱导MM细胞凋亡，抑制骨髓瘤生长，为进一步研究UBE 2 O的生物学机制提供了新的思路。
BackgroundUBE2O is proposed as a ubiquitin-conjugating enzyme, but its function was largely unknown.MethodsMass 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.ResultsUBE2O 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.ConclusionsUBE2O 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.