Deciphering the role of neddylation in tumor microenvironment modulation: common outcome of multiple signaling pathways

Abstract

Neddylation is a post-translational modification process, similar to ubiquitination, that controls several biological processes. Notably, it is often aberrantly activated in neoplasms and plays a critical role in the intricate dynamics of the tumor microenvironment (TME). This regulatory influence of neddylation permeates extensively and profoundly within the TME, affecting the behavior of tumor cells, immune cells, angiogenesis, and the extracellular matrix. Usually, neddylation promotes tumor progression towards increased malignancy. In this review, we highlight the latest understanding of the intricate molecular mechanisms that target neddylation to modulate the TME by affecting various signaling pathways. There is emerging evidence that the targeted disruption of the neddylation modification process, specifically the inhibition of cullin-RING ligases (CRLs) functionality, presents a promising avenue for targeted therapy. MLN4924, a small-molecule inhibitor of the neddylation pathway, precisely targets the neural precursor cell-expressed developmentally downregulated protein 8 activating enzyme (NAE). In recent years, significant advancements have been made in the field of neddylation modification therapy, particularly the integration of MLN4924 with chemotherapy or targeted therapy. This combined approach has demonstrated notable success in the treatment of a variety of hematological and solid tumors. Here, we investigated the inhibitory effects of MLN4924 on neddylation and summarized the current therapeutic outcomes of MLN4924 against various tumors. In conclusion, this review provides a comprehensive, up-to-date, and thorough overview of neddylation modifications, and offers insight into the critical importance of this cellular process in tumorigenesis.

Keywords: Clinical trials; MLN4924; NEDD8; Neddylation; Signaling pathway; TME.

Fig. 1

Neddylation, a complex multi-step process involving the post-translational attachment of the NEDD8 protein to target proteins, carries out various cellular functions and protein degradation. This process involves the maturation, activation, conjugation, ligation, and deneddylation stages and is conducted by specialized enzymes such as NEDP1, UBA3, and UBE2M. On the other hand, the neddylation modification significantly influences on the tumor microenvironment. This modification can impact various factors, including VEGF, PDGFB, ANGPT2, the EMT process, CAFs, and the ECM. Together, these two figures highlight the critical role of neddylation in both general cell function and the specific context of tumor progression. NEDD8, neural precursor cell expressed developmentally downregulated protein 8; UCH-L3, ubiquitin C-terminal hydrolase-L3; NEDP1, NEDD8 Protease 1; NAE1, NEDD8-activating enzyme 1; UBA3, ubiquitin-like modifier activating enzyme 3; UBE2 M/F, ubiquitin conjugating enzyme E2 M/F, CSN, COP9 signalosome; VEGF, vascular endothelial growth factor; PDGFB, platelet-derived growth factor B; ANGPT2, angiopoietin 2; EMT, epithelial-to-mesenchymal transition; CAFs, cancer-associated fibroblasts; ECM, extracellular matrix. Created with BioRender.com

Fig. 2

The interplay between the RPL11-MDM2-p53 and PI3K/AKT/mTOR pathways can be regulated by neddylation. The binding of RPL11 to MDM2 inhibits MDM2’s E3 ligase activity, preventing p53 degradation, but neddylation can hinder this binding, indirectly causing p53 degradation and affecting the expression of various target genes. On the other hand, the PI3K/AKT/mTOR pathway activation initiates when growth factors or hormones bind to cell surface receptors like RTKs or GPCRs, leading to the recruitment and activation of PI3K, which then turns PIP2 into PIP3. PIP3 acts as a docking site for proteins such as AKT and PDK1, allowing PDK1 to activate AKT. Activated AKT inhibits the TSC, a negative regulator of mTORC1, thus enabling Rheb to activate mTORC1. This pathway can be negatively regulated by PTEN, which dephosphorylates PIP3 back to PIP2, removing AKT’s activation signal. Neddylation can enhance PTEN’s nuclear translocation, strengthening the pathway’s signal transduction, while deneddylation of PTEN, dependent on NEDP1, can inhibit the PI3K/AKT/mTOR pathway. MDM2, mouse double minute 2 homolog; RPL11, ribosomal Protein L11; Ub, ubiquitin; NEDD8, neural precursor cell expressed developmentally downregulated protein 8; RTKs, receptor tyrosine kinases; GPCRs, G protein-coupled receptors; PI3K, phosphoinositide 3-kinases; PIP2, Phosphatidylinositol 4,5-bisphosphate; PIP3, Phosphatidylinositol 3,4,5-trisphosphate; TSC, tuberous sclerosis complex; mTORC1, mTOR complex 1; AKT, AKT serine/threonine kinase; PDK1, 3-Phosphoinositide Dependent Protein Kinase-1; Rheb, Ras homolog enriched in brain. Created with BioRender.com

Fig. 3

Neddylation plays a crucial role in the regulation of the NF-κB pathway and EGFR pathway, affecting several immune cells. In the NF-κB pathway, IκB inhibition and subsequent proteasomal degradation occur via IKK complex activation. The SCF complex, whose function is enhanced by neddylation, is instrumental in IκB ubiquitination. In the EGFR pathway, neddylation helps regulate the function of Tregs, dendritic cells, M2 macrophages, and CD8 + T cells. NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells; IκB, inhibitor of κB; IKK, IκB kinase; TLRs, Toll-like receptors; c-Rel, proto-oncogene c-Rel; SCF, Skp1-Cul1-F-box protein; Skp1, S-phase kinase-associated protein 1; Rbx1, ring-box 1; ROC1, regulator of Cullins 1; NEDD8, neural precursor cell expressed developmentally downregulated protein 8; UBE2M, ubiquitin-conjugating enzyme E2 M; c-CBL, casitas B-lineage lymphoma; Tregs, regulatory T cells. Created with BioRender.com

Fig. 4

The HIF signaling pathway plays a vital role in tumor angiogenesis by adjusting HIF-1α levels based on oxygen availability, leading to angiogenesis-related gene activation under hypoxic conditions, while neddylation, by inhibiting HIF-1α degradation, can promote tumor growth and angiogenesis. HIF, hypoxia-inducible factor; VHL, von Hippel-Lindau; HREs, hypoxia response elements; VEGF, vascular endothelial growth factor; PDGFB, platelet-derived growth factor B; ANGPT2, angiopoietin 2; NEDD8, neural precursor cell expressed developmentally downregulated protein 8. Created with BioRender.com

Fig. 5

The TGF-β pathway, modulated by NEDD8, contributes to tumor progression by increasing ECM protein production, regulating ECM remodeling enzymes, promoting epithelial-to-mesenchymal transition, and activating CAFs. Furthermore, neddylation, facilitated by NEDD8, indirectly regulates the TGF-β pathway by stabilizing its signaling through c-CBL, potentially enhancing tumor invasiveness and malignancy. Simultaneously, the Hippo pathway, through the ubiquitination of MST1 and LATS1/2 by CUL7 and CUL4 respectively, plays a crucial role in tumorigenesis. MST1 inhibits the kinase cascade, including LATS1 and LATS2 activation, leading to the phosphorylation of the transcriptional co-activators YAP and TEAD, key downstream effectors of the Hippo pathway, thereby modulating tumor cell growth. Thus, both the TGF-β and Hippo pathways together form a complex network influencing tumor development. N8, neural precursor cell expressed developmentally downregulated protein 8; TGF-β, transforming growth factor-β; CAFs, cancer-associated fibroblasts; c-CBL, casitas b-lineage lymphoma; UBE2M, ubiquitin-conjugating enzyme E2 M; ECM, extracellular matrix; MST1, mammalian STE20-like protein kinase 1; LATS1 and LATS2, Large tumor suppressor kinase 1 and 2; YAP, Yes-associated protein; TEAD, TEA domain. Created with BioRender.com.