Cell Counting Kit-8 br Highlights br d SPOP
d SPOP targets NANOG for degradation
d Cancer-associated SPOP mutants lost the ability to degrade NANOG
d NANOG stability is regulated by AMPK-BRAF-mediated phosphorylation
d SPOP represses prostate cancer stemness via targeting NANOG
Developmental Cell Article
AMPK Promotes SPOP-Mediated NANOG Degradation to Regulate Prostate Cancer Cell Stemness
Xinbo Wang,1, 4,5,9 Jiali Jin,1,5,9 Fangning Wan,2,3,9 Linlin Zhao,1,5,9 Hongshang Chu,5 Cong Chen,5 Guanghong Liao,5 Jian Liu,7 Yue Yu,5 Hongqi Teng,1 Lan Fang,1 Cong Jiang,5 Weijuan Pan,5 Xin Xie,7 Jia Li,7 Xiaolin Lu,2,3 Xuejun Jiang,8 Xin Ge,6,* Dingwei Ye,2,3,* and Ping Wang1,10,* 1Tongji University Cancer Center, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai 200072, China 2Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032, China 3Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China 4Shanghai Putuo People’s Hospital, School of Medicine, Tongji University, Shanghai 200060, China 5Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China 6Department of Clinical Medicine, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai 200072, China 7National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China 8Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA 9These authors contributed equally 10Lead Contact *Correspondence: [email protected] (X.G.), [email protected] (D.Y.), [email protected] (P.W.)
NANOG is an essential transcriptional factor for the maintenance of embryonic stem Cell Counting Kit-8 (ESCs) and cancer stem cells (CSCs) in prostate cancer (PCa). However, the regulation mechanism of NANOG pro-tein stability in cancer progression is still elusive. Here, we report that NANOG is degraded by SPOP, a frequently mutated tumor suppressor of PCa. Can-cer-associated mutations of SPOP or the mutation of NANOG at S68Y abrogates the SPOP-mediated NANOG degradation, leading to elevated PCa cancer stemness and poor prognosis. In addition, SPOP-mediated NANOG degradation is controlled by the AMPK-BRAF signal axis through the phosphorylation of NANOG at Ser68, which blocked the interaction be-tween SPOP and NANOG. Thus, our study provides a regulation mechanism of PCa stemness controlled by phosphorylation-mediated NANOG stability, which helps to identify novel drug targets and improve ther-apeutic strategy for PCa.
Most cancers have a small population of cells with stem cell-like properties, termed as cancer stem cells (CSCs) that are capable of self-renewal and tumor-initiation (O’Brien et al., 2007; Patrawala et al., 2006; Singh et al., 2003). Moreover, CSCs express pluripotency-related transcription factors of embryonic stem cells (ESCs), such as NANOG, OCT3/4, and SOX2 (Pece et al., 2010; Wong et al., 2008; Chambers and Tomlinson, 2009). The expression levels of these pluripotency transcriptional factors in cancers are tightly related to the development and progression of various cancers (Po et al., 2010; Suva` et al., 2013; Boumahdi et al., 2014). PCa is one
of the most common cancers in the world and the second lead-ing cause of cancer-related deaths in men (Siegel et al., 2013). Accumulating evidence indicates that the presence of CSCs is responsible for PCa initiation, progression and chemotherapy resistance (Jeter et al., 2011; Liu et al., 2010b). Therefore, in-depth understanding of the molecular underpinnings in PCa stem cell-like traits may shed light on the development of CSC-specific targeted therapy for PCa.
NANOG, an ESC transcription factor, maintains the self-renewal and pluripotency of ESCs (Chambers et al., 2003; Mitsui et al., 2003). NANOG is highly expressed in various cancers and plays a pleiotropic role in the tumorigenesis cascade, such as chemotherapy and radiation resistance, metabolism reprogram-ming and CSC population modulation (Santaliz-Ruiz et al., 2014; Chen et al., 2016). Additionally, NANOG is a critical regulator for PCa progression (Ugolkov et al., 2011), and its overexpression promotes the tumorigenesis in both androgen-sensitive and androgen-insensitive PCa cells (Zhang et al., 2014a), indicative of poor prognosis (Mathieu et al., 2011; Miyazawa et al., 2014). It has been reported that PCa cells are endowed with the stem-like properties by NANOG expression, especially under the stabilized and accumulated condition (Jeter et al., 2011; Ka-wamura et al., 2015). However, the regulatory mechanism of NANOG stability in cancers remains unclear.