Suppression of glioblastoma by targeting the overactivated protein neddylation pathway
Neuro-Oncology
Suppression of glioblastoma by targeting the overactivated protein neddylation pathway
Wei Hua 0
Chunjie Li 0
Zixiao Yang 0
Lihui Li 0
Yanan Jiang 0
Guangyang Yu 0
Wei Zhu 0
Zhengyan Liu 0
Shengzhong Duan 0
Yiwei Chu 0
Meng Yang 0
Yanmei Zhang 0
Ying Mao () 0
Lijun Jia () 0
0 Department of Neurosurgery, Huashan Hospital, Fudan University , Shanghai, China (W.H., Z.Y., W.Z., Z.L., Y.M. ); Cancer Institute, Fudan University Shanghai Cancer Center; Collaborative Innovation Center of Cancer Medicine; and Department of Oncology, Shanghai Medical College , Shanghai, China (W.H., C.L., L.L., Y.J., G.Y., L.J. ); Department of Immunology, School of Basic Medical Sciences, Fudan University , Shanghai, China (C.L., Y.J., G.Y. , Y.C.); Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China (S.D. ); AntiCancer Biotech Beijing Co. Ltd. , Beijing , China ( M.Y.); Shanghai Shines Clinical Laboratories, Inc., The Research base of MDT, DCMST, Ministry of Health , Shanghai , China (Y.Z.); The Collaborative Innovation Center for Brain Science, Fudan University , Shanghai, China, Y.M.
†These authors contributed equally to this work. Background. The neddylation pathway has been recently identified as an attractive anticancer target, and MLN4924, a specific NEDD8-activating enzyme inhibitor, has been developed as a first-in-class anticancer agent. However, neither the status of the neddylation pathway in glioblastoma (GBM) nor the effect of MLN4924 against GBM has been systematically investigated yet. Methods. To measure the activation state of the neddylation pathway in GBM, expression of the NEDD8-activating enzyme (E1), NEDD8-conjugating enzyme (E2), and global protein neddylation in GBM tumor tissues versus adjacent tissues were examined by immunoblotting analysis and immunohistochemistry staining. To assess the therapeutic efficacy of neddylation inhibition in GBM, cell proliferation in vitro and tumor growth in vivo were determined upon neddylation inhibition by MLN4924, an investigational NEDD8-activating enzyme inhibitor. Results. The neddylation pathway was overactivated in a majority of GBM tumor tissues when compared with adjacent normal tissues. The upregulation of this pathway in GBM tissues was positively correlated with high-grade disease and postoperative recurrence but was negatively associated with patient overall survival. MLN4924 treatment inhibited cullin neddylation, inactivated cullin-RING E3 ligase, and led to the accumulation of tumor-suppressive cullin-RING E3 ligase substrates to trigger cell-cycle arrest and senescence or apoptosis in a cell-line dependent manner. Moreover, inhibition of neddylation by MLN4924 significantly suppressed tumor growth in an orthotopic xenograft model of human GBM. Conclusion. Our study indicates that an overactivated neddylation pathway may be involved in GBM progression and that inhibition of this oncogenic pathway is a potentially new therapeutic approach for GBM.
cullin-RING E3 ligase; glioblastoma; MLN4924; neddylation; NEDD8
Introduction
Glioblastoma (GBM) is the most malignant primary brain tumor.
The prognosis for patients with GBM remains unsatisfactory as
they are frequently treated with a combination of surgery,
radiation, and traditional chemotherapy.1,2 In the last decades,
great effort has been focused on understanding the molecular
mechanisms of the initiation and progression of GBM.3
However, little progress has been achieved in the transition from
understanding this disease to successfully treating it.4 Thus, it
is urgent to identify novel anti-GBM targets and develop more
effective therapeutic strategies for the treatment of GBM.
Protein homeostasis maintains normal cellular function. The
ubiquitin-proteasome system (UPS) is responsible for regulating
multiple biological processes through timely degradation of
unwanted proteins. Because of its essential role in maintaining
intracellular homeostasis, dysregulation of UPS is involved in
the development of many diseases including cancer.5,6
Therefore, targeting UPS represents an attractive therapeutic strategy
for human cancers. Bortezomib (also known as Velcade or
PS-341) is a first-in-class general proteasome inhibitor, approved
by the FDA for the treatment of patients with multiple myeloma
or mantle cell lymphoma.7,8 However, the drug lacks specificity
due to overall inhibition on the degradation of
proteasomemediated proteins, which may contribute to clinical toxicity.
Thus, numerous efforts have been focused on improving
specificity by targeting the components upstream of the proteasome,
especially substrate-specific E3 ubiquitin ligase.9
Neddylation is a recently identified protein posttranslational
modification pathway through which NEDD8 (neural precursor
cell expressed, developmentally downregulated 8) is
conjugated to target proteins for the regulation of protein (...truncated)