Both BRCA1-wild type and -mutant triple-negative breast cancers show sensitivity to the NAE inhibitor MLN4924 which is enhanced upon MLN4924 and cisplatin combination treatment

MLN4924 Suppresses head and neck squamous cell carcinoma progression by inactivating the mTOR signaling pathway via the NEDD8/CUL4/TSC2 axis

Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with a five-year survival rate below 50 %. Standard treatments for HNSCC include surgery, radiotherapy, chemotherapy, and targeted therapies, but they still have significant limitations. Neddylation, a post-translational modification involving the attachment of NEDD8 (neural precursor cells expressed developmentally down-regulated 8) to proteins, is frequently dysregulated in HNSCC, thereby promoting tumor growth. MLN4924, also known as Pevonedistat, is a Neddylation inhibitor that has shown promise in suppressing HNSCC cell proliferation and invasion, establishing it as a potential therapeutic option. However, its precise molecular mechanism remains unclear. This study aims to investigate the mechanism of MLN4924 in HNSCC. This study examined the effects of MLN4924 on HNSCC and its associated molecular pathways. Bioinformatic analysis indicated that NEDD8, a critical component of the Neddylation pathway, is linked to poor prognosis and the mTOR (mammalian target of rapamycin) signaling pathway in HNSCC. MLN4924 significantly suppressed cell migration, invasion, and the epithelial-mesenchymal transition (EMT) pathway, and downregulated NEDD8 expression. Mechanistic studies demonstrated that MLN4924 inhibited the binding of NEDD8 to cullin4 (CUL4) and prevented the Neddylation of tuberous sclerosis complex 2 (TSC2), leading to the inactivation of the mTOR pathway. These findings were confirmed in vivo, where MLN4924 effectively inhibited tumor growth. Overall, MLN4924 disrupted Neddylation pathway and stabilized TSC2, thereby inactivating the mTOR pathway. The study provided a theoretical basis for the clinical potential of MLN4924 in improving treatment outcomes for HNSCC patients, offering a novel strategy for addressing this challenging disease.

Protein neddylation and its role in health and diseases

NEDD8 (Neural precursor cell expressed developmentally downregulated protein 8) is an ubiquitin-like protein that is covalently attached to a lysine residue of a protein substrate through a process known as neddylation, catalyzed by the enzyme cascade, namely NEDD8 activating enzyme (E1), NEDD8 conjugating enzyme (E2), and NEDD8 ligase (E3). The substrates of neddylation are categorized into cullins and non-cullin proteins. Neddylation of cullins activates CRLs (cullin RING ligases), the largest family of E3 ligases, whereas neddylation of non-cullin substrates alters their stability and activity, as well as subcellular localization. Significantly, the neddylation pathway and/or many neddylation substrates are abnormally activated or over-expressed in various human diseases, such as metabolic disorders, liver dysfunction, neurodegenerative disorders, and cancers, among others. Thus, targeting neddylation becomes an attractive strategy for the treatment of these diseases. In this review, we first provide a general introduction on the neddylation cascade, its biochemical process and regulation, and the crystal structures of neddylation enzymes in complex with cullin substrates; then discuss how neddylation governs various key biological processes via the modification of cullins and non-cullin substrates. We further review the literature data on dysregulated neddylation in several human diseases, particularly cancer, followed by an outline of current efforts in the discovery of small molecule inhibitors of neddylation as a promising therapeutic approach. Finally, few perspectives were proposed for extensive future investigations.

Advancements in colorectal cancer research: Unveiling the cellular and molecular mechanisms of neddylation (Review)

Neddylation, akin to ubiquitination, represents a post‑translational modification of proteins wherein neural precursor cell‑expressed developmentally downregulated protein 8 (NEDD8) is modified on the substrate protein through a series of reactions. Neddylation plays a pivotal role in the growth and proliferation of animal cells. In colorectal cancer (CRC), it predominantly contributes to the proliferation, metastasis and survival of tumor cells, decreasing overall patient survival. The strategic manipulation of the NEDD8‑mediated neddylation pathway holds immense therapeutic promise in terms of the potential to modulate the growth of tumors by regulating diverse biological responses within cancer cells, such as DNA damage response and apoptosis, among others. MLN4924 is an inhibitor of NEDD8, and its combined use with platinum drugs and irinotecan, as well as cycle inhibitors and NEDD activating enzyme inhibitors screened by drug repurposing, has been found to exert promising antitumor effects. The present review summarizes the recent progress made in the understanding of the role of NEDD8 in the advancement of CRC, suggesting that NEDD8 is a promising anti‑CRC target.

Targeting cullin neddylation for cancer and fibrotic diseases

Protein neddylation is a post-translational modification, and its best recognized substrates are cullin family proteins, which are the core component of Cullin-RING ligases (CRLs). Given that most neddylation pathway proteins are overactivated in different cancers and fibrotic diseases, targeting neddylation becomes an emerging approach for the treatment of these diseases. To date, numerous neddylation inhibitors have been developed, of which MLN4924 has entered phase I/II/III clinical trials for cancer treatment, such as acute myeloid leukemia, melanoma, lymphoma and solid tumors. Here, we systematically describe the structures and biological functions of the critical enzymes in neddylation, highlight the medicinal chemistry advances in the development of neddylation inhibitors and propose the perspectives concerning targeting neddylation for cancer and fibrotic diseases.

Triple Negative Breast Cancer Treatment Options and Limitations: Future Outlook

Triple negative breast cancer (TNBC) has a negative expression of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptors (HER2). The survival rate for TNBC is generally worse than other breast cancer subtypes. TNBC treatment has made significant advances, but certain limitations remain. Treatment for TNBC can be challenging since the disease has various molecular subtypes. A variety of treatment options are available, such as chemotherapy, immunotherapy, radiotherapy, and surgery. Chemotherapy is the most common of these options. TNBC is generally treated with systemic chemotherapy using drugs such as anthracyclines and taxanes in neoadjuvant or adjuvant settings. Developing resistance to anticancer drugs and off-target toxicity are the primary hindrances to chemotherapeutic solutions for cancer. It is imperative that researchers, clinicians, and pharmaceutical companies work together to develop effective treatment options for TNBC. Several studies have suggested nanotechnology as a potential solution to the problem of suboptimal TNBC treatment. In this review, we summarized possible treatment options for TNBC, including chemotherapy, immunotherapy, targeted therapy, combination therapy, and nanoparticle-based therapy, and some solutions for the treatment of TNBC in the future. Moreover, we gave general information about TNBC in terms of its characteristics and aggressiveness.

Thioparib inhibits homologous recombination repair, activates the type I IFN response, and overcomes olaparib resistance

Poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have shown great promise for treating BRCA-deficient tumors. However, over 40% of BRCA-deficient patients fail to respond to PARPi. Here, we report that thioparib, a next-generation PARPi with high affinity against multiple PARPs, including PARP1, PARP2, and PARP7, displays high antitumor activities against PARPi-sensitive and -resistant cells with homologous recombination (HR) deficiency both in vitro and in vivo. Thioparib treatment elicited PARP1-dependent DNA damage and replication stress, causing S-phase arrest and apoptosis. Conversely, thioparib strongly inhibited HR-mediated DNA repair while increasing RAD51 foci formation. Notably, the on-target inhibition of PARP7 by thioparib-activated STING/TBK1-dependent phosphorylation of STAT1, triggered a strong induction of type I interferons (IFNs), and resulted in tumor growth retardation in an immunocompetent mouse model. However, the inhibitory effect of thioparib on tumor growth was more pronounced in PARP1 knockout mice, suggesting that a specific PARP7 inhibitor, rather than a pan inhibitor such as thioparib, would be more relevant for clinical applications. Finally, genome-scale CRISPR screening identified PARP1 and MCRS1 as genes capable of modulating thioparib sensitivity. Taken together, thioparib, a next-generation PARPi acting on both DNA damage response and antitumor immunity, serves as a therapeutic potential for treating hyperactive HR tumors, including those resistant to earlier-generation PARPi.

CEDA: integrating gene expression data with CRISPR-pooled screen data identifies essential genes with higher expression

MOTIVATION

Clustered regularly interspaced short palindromic repeats (CRISPR)-based genetic perturbation screen is a powerful tool to probe gene function. However, experimental noises, especially for the lowly expressed genes, need to be accounted for to maintain proper control of false positive rate.

METHODS

We develop a statistical method, named CRISPR screen with Expression Data Analysis (CEDA), to integrate gene expression profiles and CRISPR screen data for identifying essential genes. CEDA stratifies genes based on expression level and adopts a three-component mixture model for the log-fold change of single-guide RNAs (sgRNAs). Empirical Bayesian prior and expectation-maximization algorithm are used for parameter estimation and false discovery rate inference.

RESULTS

Taking advantage of gene expression data, CEDA identifies essential genes with higher expression. Compared to existing methods, CEDA shows comparable reliability but higher sensitivity in detecting essential genes with moderate sgRNA fold change. Therefore, using the same CRISPR data, CEDA generates an additional hit gene list.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

NPRL2 reduces the niraparib sensitivity of castration-resistant prostate cancer via interacting with UBE2M and enhancing neddylation

In this study, we explored the regulatory effects of nitrogen permease regulator 2-like (NPRL2) on niraparib sensitivity, a PARP inhibitor (PARPi) in castrate-resistant prostate cancer (CRPC). Data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) program were retrospectively examined. Gene-set enrichment analysis (GSEA) was conducted between high and low NRPL2 expression prostate adenocarcinoma (PRAD) cases in TCGA. CCK-8 assay, Western blot analysis of apoptotic proteins, and flow cytometric analysis of apoptosis were applied to test niraparib sensitivity. Immunofluorescent (IF) staining and co-immunoprecipitation (co-IP) were conducted to explore the proteins interacting with NPRL2. Results showed that the upregulation of a canonical protein-coding transcript of NPRL2 (ENST00000232501.7) is associated with an unfavorable prognosis. Bioinformatic analysis predicts a physical interaction between NPRL2 and UBE2M, which is validated by a following Co-IP assay. This interaction increases NPRL2 stability by reducing polyubiquitination and proteasomal degradation. Depletion of NPRL2 or UBE2M significantly increases the niraparib sensitivity of CRPC cells and enhances niraparib-induced tumor growth inhibition in vivo. NPRL2 cooperatively enhances UBE2M-mediated neddylation and facilitates the degradation of multiple substrates of Cullin-RING E3 ubiquitin ligases (CRLs). In conclusion, this study identified a novel NPRL2-UBE2M complex in modulating neddylation and niraparib sensitivity of CRPC cells. Therefore, targeting NPRL2 might be considered as an adjuvant strategy for PARPi therapy.