www.impactjournals.com/oncotarget/ Oncotarget, Vol. 7, No. 24 Research Paper OTUB1-catalyzed deubiquitination of FOXM1 facilitates tumor progression and predicts a poor prognosis in ovarian cancer Yiqin Wang1, Xianrong Zhou1, Midie Xu2,3,4,5, Weiwei Weng2,3,4,5, Qiongyan Zhang2,3,4,5, Yusi Yang2,3,4,5, Ping Wei2,4,6, Xiang Du2,3,4,5 1Department of Pathology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200044, China 2Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai 200032, China 3Department of Pathology, Shanghai Medical College, Fudan University, Shanghai 200032, China 4Institute of Pathology, Fudan University, Shanghai 200032, China 5Institute of Biomedical Sciences, Fudan University, Shanghai 200032, China 6Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai 200032, China Correspondence to: Ping Wei, e-mail:
[email protected] Xiang Du, e-mail:
[email protected] Keywords: OTUB1, FOXM1, ovarian carcinoma, ubiquitination, deubiquitination Received: August 12, 2015 Accepted: April 22, 2016 Published: May 4, 2016 ABSTRACT Ubiquitination is essential for regulation of cell physiology, protein stability, and signal transduction [1]. Its dysregulation is an important factor in many diseases, including cancer. We explored the potential OTUB1-catalyzed deubiquitination of FOXM1, a transcription factor linked to carcinogenesis, and the biological consequence of that interaction in ovarian cancer. We found that FOXM1 is ubiquitinated by multiple polyUb chains and targeted for proteosomal degradation in a reaction dependent on its ubiquitination-required KEN box. Additionally, the OTUB1 N-terminus and catalytic triad bind to FOXM1, specifically catalyzing cleavage of the K48-specific ubiquitin linkage from FOXM1. Moreover, OTUB1-FOXM1 interaction drives tumor progression and OTUB1 expression predicts a poor prognosis in ovarian cancer.