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Saitoh Y, Hamano A, Mochida K, Kakeya A, Uno M, Tsuruyama E, Ichikawa H, Tokunaga F, Utsunomiya A, Watanabe T, Yamaoka S. A20 targets caspase-8 and FADD to protect HTLV-I-infected cells. Leukemia 2015; 30:716-27. [PMID: 26437781 DOI: 10.1038/leu.2015.267] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 08/31/2015] [Accepted: 09/18/2015] [Indexed: 12/15/2022]
Abstract
Adult T-cell leukemia (ATL) arises from a human T-cell leukemia virus type I (HTLV-I)-infected cell and has few therapeutic options. Here, we have uncovered a previously unrecognized role for a ubiquitin-editing enzyme A20 in the survival of HTLV-I-infected cells. Unlike in lymphomas of the B-cell lineage, A20 is abundantly expressed in primary ATL cells without notable mutations. Depletion of A20 in HTLV-I-infected cells resulted in caspase activation, cell death induction and impaired tumorigenicity in mouse xenograft models. Mechanistically, A20 stably interacts with caspase-8 and Fas-associated via death domain (FADD) in HTLV-I-infected cells. Mutational studies revealed that A20 supports the growth of HTLV-I-infected cells independent of its catalytic functions and that the zinc-finger domains are required for the interaction with and regulation of caspases. These results indicate a pivotal role for A20 in the survival of HTLV-I-infected cells and implicate A20 as a potential therapeutic target in ATL.
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Affiliation(s)
- Y Saitoh
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - A Hamano
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - K Mochida
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - A Kakeya
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - M Uno
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Comprehensive Reproductive Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - E Tsuruyama
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - H Ichikawa
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - F Tokunaga
- Laboratory of Molecular Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - A Utsunomiya
- Department of Hematology, Imamura Bun-in Hospital, Kagoshima, Japan
| | - T Watanabe
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - S Yamaoka
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
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