Neddylation Inhibitor Research Articles

Transcriptional inhibition after irradiation occurs preferentially at highly expressed genes in a manner dependent on cell cycle progression

In response to DNA double-strand damage, ongoing transcription is inhibited to facilitate accurate DNA repair while transcriptional recovery occurs after DNA repair is complete. However, the mechanisms at play and the identity of the transcripts being regulated in this manner are unclear. In contrast to the situation following UV damage, we found that transcriptional recovery after ionizing radiation (IR) occurs in a manner independent of the HIRA histone chaperone. Sequencing of the nascent transcripts identified a programmed transcriptional response, where certain transcripts and pathways are rapidly downregulated after IR, while other transcripts and pathways are upregulated. Specifically, most of the loss of nascent transcripts occurring after IR is due to inhibition of transcriptional initiation of the highly transcribed histone genes and the rDNA. To identify factors responsible for transcriptional inhibition after IR in an unbiased manner, we performed a whole genome gRNA library CRISPR/Cas9 screen. Many of the top hits on our screen were factors required for protein neddylation. However, at short times after inhibition of neddylation, transcriptional inhibition still occurred after IR, even though neddylation was effectively inhibited. Persistent inhibition of neddylation blocked transcriptional inhibition after IR, and it also leads to cell cycle arrest. Indeed, we uncovered that many inhibitors and conditions that lead to cell cycle arrest in G1 or G2 phase also prevent transcriptional inhibition after IR. As such, it appears that transcriptional inhibition after IR occurs preferentially at highly expressed genes in cycling cells.

Transcriptional inhibition after irradiation occurs preferentially at highly expressed genes in a manner dependent on cell cycle progression.

In response to DNA double-strand damage, ongoing transcription is inhibited to facilitate accurate DNA repair while transcriptional recovery occurs after DNA repair is complete. However, the mechanisms at play and the identity of the transcripts being regulated in this manner are unclear. In contrast to the situation following UV damage, we found that transcriptional recovery after ionizing radiation (IR) occurs in a manner independent of the HIRA histone chaperone. Sequencing of the nascent transcripts identified a programmed transcriptional response, where certain transcripts and pathways are rapidly downregulated after IR, while other transcripts and pathways are upregulated. Specifically, most of the loss of nascent transcripts occurring after IR is due to inhibition of transcriptional initiation of the highly transcribed histone genes and the rDNA. To identify factors responsible for transcriptional inhibition after IR in an unbiased manner, we performed a whole genome gRNA library CRISPR/Cas9 screen. Many of the top hits on our screen were factors required for protein neddylation. However, at short times after inhibition of neddylation, transcriptional inhibition still occurred after IR, even though neddylation was effectively inhibited. Persistent inhibition of neddylation blocked transcriptional inhibition after IR, and it also leads to cell cycle arrest. Indeed, we uncovered that many inhibitors and conditions that lead to cell cycle arrest in G1 or G2 phase also prevent transcriptional inhibition after IR. As such, it appears that transcriptional inhibition after IR occurs preferentially at highly expressed genes in cycling cells.

Neddylation and Its Target Cullin 3 Are Essential for Adipocyte Differentiation.

The ongoing obesity epidemic has raised awareness of the complex physiology of adipose tissue. Abnormal adipocyte differentiation results in the development of systemic metabolic disorders such as insulin resistance and diabetes. The conjugation of NEDD8 (neural precursor cell expressed, developmentally downregulated 8) to target protein, termed neddylation, has been shown to mediate adipogenesis. However, much remains unknown about its role in adipogenesis. Here, we demonstrated that neddylation and its targets, the cullin (CUL) family members, are differentially regulated during mouse and human adipogenesis. Inhibition of neddylation by MLN4924 significantly reduced adipogenesis of 3T3-L1 and human stromal vascular cells. Deletion of NAE1, a subunit of the only NEDD8 E1 enzyme, suppressed neddylation and impaired adipogenesis. Neddylation deficiency did not affect mitotic cell expansion. Instead, it disrupted CREB/CEBPβ/PPARγ signaling, essential for adipogenesis. Interestingly, among the neddylation-targeted CUL family members, deletion of CUL3, but not CUL1, CUL2, or CUL4A, largely replicated the adipogenic defects observed with neddylation deficiency. A PPARγ agonist minimally rescued the adipogenic defects caused by the deletion of NAE1 and CUL3. In conclusion, our study demonstrates that neddylation and its targeted CUL3 are crucial for adipogenesis. These findings provide potential targets for therapeutic intervention in obesity and metabolic disorders.

An Anti-Invasive Role for Mdmx through the RhoA GTPase under the Control of the NEDD8 Pathway.

Mdmx (Mdm4) is established as an oncogene mainly through repression of the p53 tumour suppressor. On the other hand, anti-oncogenic functions for Mdmx have also been proposed, but the underlying regulatory pathways remain unknown. Investigations into the effect of inhibitors for the NEDD8 pathway in p53 activation, human cell morphology, and in cell motility during gastrulation in Xenopus embryos revealed an anti-invasive function of Mdmx. Through stabilisation and activation of the RhoA GTPase, Mdmx is required for the anti-invasive effects of NEDDylation inhibitors. Mechanistically, through its Zn finger domain, Mdmx preferentially interacts with the inactive GDP-form of RhoA. This protects RhoA from degradation and allows for RhoA targeting to the plasma membrane for its subsequent activation. The effect is transient, as prolonged NEDDylation inhibition targets Mdmx for degradation, which subsequently leads to RhoA destabilisation. Surprisingly, Mdmx degradation requires non-NEDDylated (inactive) Culin4A and the Mdm2 E3-ligase. This study reveals that Mdmx can control cell invasion through RhoA stabilisation/activation, which is potentially linked to the reported anti-oncogenic functions of Mdmx. As inhibitors of the NEDD8 pathway are in clinical trials, the status of Mdmx may be a critical determinant for the anti-tumour effects of these inhibitors.

The blockade of neddylation alleviates ventilator-induced lung injury by reducing stretch-induced damage to pulmonary epithelial cells

Ventilator-induced lung injury is a serious complication in mechanically ventilated patients. Neddylation, the post-translational modification of neural precursor cell-expressed developmentally down-regulated 8 (NEDD8) conjugation, regulates numerous biological functions. However, its involvement and therapeutic significance in ventilator-induced lung injury remains unknown. Therefore, this study aimed to examine the kinetics and contribution of activated neddylation and the impact of neddylation inhibition in mice subjected to high tidal volume (HTV) ventilation in vivo and human pulmonary alveolar epithelial cells stimulated through cyclic stretching (CS) in vitro. The neddylation and expression of ubiquitin conjugating enzyme 3 (UBA3), a NEDD8-activating enzyme (NAE) catalytic subunit, were time-dependently upregulated in HTV-ventilated mice. Additionally, the NAE inhibitor MLN4924 considerably attenuated acute lung injury induced by HTV ventilation, manifesting as reduced inflammation and oxidative stress. Furthermore, MLN4924 effectively reduced the secretion of inflammatory cytokines from Ly6Chigh monocytes and neutrophils, subsequently decreasing endothelial permeability. Moreover, our study revealed an upregulation of the neddylation pathway, oxidative stress, and apoptosis during CS of alveolar epithelial cells. However, blockade of neddylation via MLN4924 or through UBA3 knockdown suppressed this upregulation. Overall, the inhibition of neddylation may alleviate HTV-induced acute lung injury by preventing CS-induced damage to alveolar epithelial cells. This indicates that the neddylation pathway plays a critical role in the progression of ventilator-induced lung injury. These findings may provide a new therapeutic target for treating ventilator-induced lung injury.

Promising Therapeutic Strategies for Hematologic Malignancies: Innovations and Potential.

In this review we explore innovative approaches in the treatment of hematologic cancers by combining various therapeutic modalities. We discuss the synergistic potential of combining inhibitors targeting different cellular pathways with immunotherapies, molecular therapies, and hormonal therapies. Examples include combining PI3K inhibitors with proteasome inhibitors, NF-κB inhibitors with immunotherapy checkpoint inhibitors, and neddylation inhibitors with therapies targeting the tumor microenvironment. Additionally, we discuss the potential use of small molecules and peptide inhibitors in hematologic cancer treatment. These multidimensional therapeutic combinations present promising strategies for enhancing treatment efficacy and overcoming resistance mechanisms. However, further clinical research is required to validate their effectiveness and safety profiles in hematologic cancer patients.

Development of 4′-Oxo-MLN4924 as potential neddylation inhibitors: Design, synthesis, anti-HCMV evaluation, and molecular docking

MLN4924 (1), a neddylation inhibitor, has shown promising anticancer and antiviral properties. In this study, we designed and synthesized new derivatives of 4′-oxo-MLN4924, inspired by the structures of MLN4924 and another known neddylation inhibitor, referred to as compound 2. Like compound 2, we used a specific type of sugar molecule but incorporated a modified building block known as 7-deazapurine for the nucleobase part. Additionally, we arranged the sulfamate and 2′-hydroxyl as key functional groups. We found that the 2′-OH group is essential for activity against human cytomegalovirus (HCMV) using luciferase reporter assay. Molecular docking and molecular dynamics (MD) studies revealed that the conformation of the sugar moiety plays a crucial role in protein–ligand interactions. These studies suggest that derivatives with a bulky aromatic ring at the 6-position of the nucleobase are likely to have enhanced binding, which is supported by experimental findings.

Ubiquitination plays an important role during the formation of chicken primordial germ cells.

As an important posttranslational modification, ubiquitination plays an important role in regulating protein homeostasis in eukaryotic cells. In our previous studies, both the transcriptome and proteome suggested that ubiquitination is involved in the formation of chicken primordial germ cells (PGCs). Here, affinity enrichment combined with liquid chromatography-tandem mass spectrometry (MS/MS) was used to analyze the ubiquitome during the differentiation from embryonic stem cells to PGCs, and we identify that 724 lysine ubiquitinated sites were up-regulated in 558 proteins and 138 lysine ubiquitinated sites were down-regulated in 109 proteins. Furthermore, GO and KEGG enrichment analysis showed that ubiquitination regulates key proteins to participate in the progression of key events related to PGC formation and the transduction of key signals such as Wnt, MAPK, and insulin signals, followed by the detailed explanation of the specific regulatory mechanism of ubiquitination through the combined proteome and ubiquitome analysis. Moreover, both the activation and inhibition of neddylation were detrimental to the maintenance of the biological characteristics of PGCs, which also verified the importance of ubiquitination. In conclusion, this study provides a global view of the ubiquitome during the formation of PGCs by label-free quantitative ubiquitomics, which lays a theoretical foundation for the formation mechanism and specific application of chicken PGCs.

Targeted degradation of undruggable proteins using a novel heterobifunctional proteomimetic platform.

47 Background: Of the ~20,000 proteins in the human genome, only a subset can be modulated via traditional pharmacological approaches. “Undruggable” targets currently include proteins with pivotal roles in cancer pathogenesis. Our work aims to introduce a new paradigm for engaging these clinically relevant proteins using a modular platform we term the HYbrid DegRAding Copolymers (HYDRACs). HYDRACs multiplex targeting warheads with degradation inducers and have long circulation times plus high cell uptake. Preliminary studies on MYC and RAS, targets of great pharmaceutical interest, highlight the potential of this platform to revolutionize drug design. Methods: HYDRACs containing MYC or RAS targeting peptides randomly copolymerized with degrons were synthesized using ROMP. Fluorescent and biotin-tags were incorporated for use in uptake and pull-down assays. Viability following treatment with MYC-HYDRACs was performed in multiple cell lines with both cellular (MYC-independent lines) and polymer composition controls. Target engagement was assessed via immunoprecipitation and circular dichroism with protein degradation monitored by WB. Unbiased whole proteome analysis and RNAseq were done to confirm observed effects were selectively on-target. In vivo efficacy and biodistribution was assessed in tumor-bearing mice. Results: HYDRACs show high levels of cell uptake and antiproliferative effects at sub-micromolar concentrations in a formulation- and target-dependent manner. Cells treated with MYC-HYDRACs displayed reduced MYC protein levels, which were rescued by proteasome or neddylation inhibition. Swapping out the degron for various validated E3 ligase recruiters maintained MYC degradation, highlighting the “plug-and-play” nature of this approach. On-target activity was confirmed via RNAseq. Biophysical analysis showed strong HYDRAC-protein interactions, orthogonally supported by the presence of target protein following pull-down of biotin-terminated HYDRACs. Target protein degradation only occurred following treatment with an intact HYDRAC compound. Mice bearing MYC-CaP tumors showed delayed tumor growth following treatment with MYC-HYDRACs, with compound accumulation in the tumor for up to 72 h following a single injection. Generalizability was demonstrated against RAS, with RAS-HYDRACs capable of degrading KRAS across multiple different alleles, acting as a pan-KRAS degrader. Conclusions: We present a novel platform technology that addresses the challenges inherent to peptide delivery approaches. HYDRACs have the potential to dramatically alter the drug discovery landscape, allowing for the development of cancer-relevant target modulators for which there are no current viable therapies. We envision the HYDRAC platform as a generalizable approach to designing degraders of proteins of interest, greatly expanding the therapeutic armamentarium for TPD.

The CRL3KCTD10 ubiquitin ligase–USP18 axis coordinately regulates cystine uptake and ferroptosis by modulating SLC7A11

SLC7A11 is a cystine transporter and ferroptosis inhibitor. How the stability of SLC7A11 is coordinately regulated in response to environmental cystine by which E3 ligase and deubiquitylase (DUB) remains elusive. Here, we report that neddylation inhibitor MLN4924 increases cystine uptake by causing SLC7A11 accumulation, via inactivating Cullin-RING ligase-3 (CRL-3). We identified KCTD10 as the substrate-recognizing subunit of CRL-3 for SLC7A11 ubiquitylation, and USP18 as SLC7A11 deubiquitylase. Upon cystine deprivation, the protein levels of KCTD10 or USP18 are decreased or increased, respectively, contributing to SLC7A11 accumulation. By destabilizing or stabilizing SLC7A11, KCTD10, or USP18 inversely regulates the cystine uptake and ferroptosis. Biologically, MLN4924 combination with SLC7A11 inhibitor Imidazole Ketone Erastin (IKE) enhanced suppression of tumor growth. In human breast tumor tissues, SLC7A11 levels were negatively or positively correlated with KCTD10 or USP18, respectively. Collectively, our study defines how SLC7A11 and ferroptosis is coordinately regulated by the CRL3KCTD10/E3-USP18/DUB axis, and provides a sound rationale of drug combination to enhance anticancer efficacy.

NEDD8 enhances Hippo signaling by mediating YAP1 neddylation

The Hippo-YAP signaling pathway plays a central role in many biological processes such as regulating cell fate, organ size and tissue growth, and its key components are spatiotemporally expressed and post-translationally modified during these processes. Neddylation is a post-translational modification that involves the covalent attachment of NEDD8 to target proteins by NEDD8-specific E1-E2-E3 enzymes. Whether neddylation is involved in Hippo-YAP signaling remains poorly understood. Here, we provide evidence supporting the critical role of NEDD8 in facilitating the Hippo-YAP signaling pathway by mediating neddylation of the transcriptional coactivator Yes-associated protein 1 (YAP1). Overexpression of NEDD8 induces YAP1 neddylation and enhances YAP1 transactivity, but inhibition of neddylation suppresses YAP1 transactivity and attenuates YAP1 nuclear accumulation. Furthermore, inhibition of YAP1 signaling promotes MLN4924-induced GCs apoptosis and disruption of nedd8 in zebrafish results in downregulation of yap1-activated genes and upregulation of yap1-repressed genes. Further assays show that the xiap ligase promotes nedd8 conjugates to yap1 and that yap1 neddylation. In addition, we identify lysine 159 as a major neddylation site on YAP1. These findings reveal a novel mechanism for neddylation in the regulation of Hippo-YAP signaling.

Neddylation activated TRIM25 desensitizes triple-negative breast cancer to paclitaxel via TFEB-mediated autophagy

BackgroundPaclitaxel (PTX) treatment resistance is an important factor leading to poor prognosis in triple-negative breast cancer (TNBC), therefore there is an urgent need to identify new target for combination therapy. Neddylation is a post-translational process that introduces a ubiquitin-like protein called neural precursor cell expressed developmentally downregulated protein 8 (NEDD8). Previous studies have found that neddylation is activated in multiple tumors, but its relationship with PTX chemotherapy sensitivity has not been reported.MethodsDifferences in UBC12 and NEDD8 expression levels between PTX-sensitive and PTX-insensitive TNBC tissues were validated using public databases and immunohistochemistry. The in vitro and in vivo functional experiments were used to observe the effect of neddylation inhibition combined with PTX therapy on tumor progression. Co-IP, western blot and PCR assays were used to investigate the molecular mechanisms. Molecular docking was used to simulate the protein binding of UBC12 and TRIM25. Molecular dynamics simulation was used to observe the changes in TRIM25 protein conformation.ResultsWe found that in TNBC that is insensitive to PTX, NEDD8 and NEDD8 conjugating enzyme UBC12 are highly expressed. Treatment with the NEDD8-activating enzyme (NAE) inhibitor mln4924 or knockdown of UBC12 significantly increased the sensitivity of the tumor to PTX, and this increase in sensitivity is related to UBC12-mediated autophagy activation. Mechanistically, UBC12 can transfer NEDD8 to E3 ubiquitin ligase tripartite motif containing 25 (TRIM25) at K117. Molecular dynamics simulations indicate that the neddylation modification of TRIM25 reduces steric hindrance in its RING domain, facilitating the binding of TRIM25 and ubiquitylated substrates. Subsequently, TRIM25 promotes the nuclear translocation of transcription factor EB (TFEB) and transcription of autophagy related genes by increasing K63-polyubiquitination of TFEB, thereby reducing tumor sensitivity to PTX.ConclusionsNeddylation is activated in PTX-insensitive TNBC. Specifically, autophagy gene transcriptional activation mediated by the UBC12/TRIM25/TFEB axis reduces TNBC sensitivity to PTX. Neddylation suppression combination with PTX treatment shows a synergistic anti-tumor effect.

Genome-wide CRISPR screen identifies neddylation as a regulator of neuronal aging and AD neurodegeneration

Aging is the biggest risk factor for the development of Alzheimer's disease (AD). Here, we performed a whole-genome CRISPR screen to identify regulators of neuronal age and show that the neddylation pathway regulates both cellular age and AD neurodegeneration in a human stem cell model. Specifically, we demonstrate that blocking neddylation increased cellular hallmarks of aging and led to an increase in Tau aggregation and phosphorylation in neurons carrying the APPswe/swe mutation. Aged APPswe/swe but not isogenic control neurons also showed a progressive decrease in viability. Selective neuronal loss upon neddylation inhibition was similarly observed in other isogenic AD and in Parkinson's disease (PD) models, including PSENM146V/M146V cortical and LRRK2G2019S/G2019S midbrain dopamine neurons, respectively. This study indicates that cellular aging can reveal late-onset disease phenotypes, identifies new potential targets to modulate AD progression, and describes a strategy to program age-associated phenotypes into stem cell models of disease.

Inhibition of neddylation disturbs zygotic genome activation through histone modification change and leads to early development arrest in mouse embryos

Post-translational modification and fine-tuned protein turnover are of great importance in mammalian early embryo development. Apart from the classic protein degradation promoting ubiquitination, new forms of ubiquitination-like modification are yet to be fully understood. Here, we demonstrate the function and potential mechanisms of one ubiquitination-like modification, neddylation, in mouse preimplantation embryo development. Treated with specific inhibitors, zygotes showed a dramatically decreased cleavage rate and almost all failed to enter the 4-cell stage. Transcriptional profiling showed genes were differentially expressed in pathways involving cell fate determination and cell differentiation, including several down-regulated zygotic genome activation (ZGA) marker genes. A decreased level of phosphorylated RNA polymerase II was detected, indicating impaired gene transcription inside the embryo cell nucleus. Proteomic data showed that differentially expressed proteins were enriched in histone modifications. We confirmed the lowered in methyltransferase (KMT2D) expression and a decrease in histone H3K4me3. At the same time, acetyltransferase (CBP/p300) reduced, while deacetylase (HDAC6) increased, resulting in an attenuation in histone H3K27ac. Additionally, we observed the up-regulation in YAP1 and RPL13 activities, indicating potential abnormalities in the downstream response of Hippo signaling pathway. In summary, we found that inhibition of neddylation induced epigenetic changes in early embryos and led to abnormalities in related downstream signaling pathways. This study sheds light upon new forms of ubiquitination regulating mammalian embryonic development and may contribute to further investigation of female infertility pathology.

Transcriptional inhibition after irradiation occurs preferentially at highly expressed genes in a manner dependent on cell cycle progression.

In response to DNA double strand damage, ongoing transcription is inhibited to facilitate accurate DNA repair while transcriptional recovery occurs after DNA repair is complete. However, the mechanisms at play and identity of the transcripts being regulated in this manner are unclear. In contrast to the situation following UV damage, we found that transcriptional recovery after ionizing radiation (IR) occurs in a manner independent of the HIRA histone chaperone. Sequencing of the nascent transcripts identified a programmed transcriptional response, where certain transcripts and pathways are rapidly downregulated after IR, while other transcripts and pathways are upregulated. Specifically, most of the loss of nascent transcripts occurring after IR is due to inhibition of transcriptional initiation of the highly transcribed histone genes and the rDNA. To identify factors responsible for transcriptional inhibition after IR in an unbiased manner, we performed a whole genome gRNA library CRISPR / Cas9 screen. Many of the top hits in our screen were factors required for protein neddylation. However, at short times after inhibition of neddylation, transcriptional inhibition still occurred after IR, even though neddylation was effectively inhibited. Persistent inhibition of neddylation blocked transcriptional inhibition after IR, and it also leads to cell cycle arrest. Indeed, we uncovered that many inhibitors and conditions that lead to cell cycle arrest in G1 or G2 phase also prevent transcriptional inhibition after IR. As such, it appears that transcriptional inhibition after IR occurs preferentially at highly expressed genes in cycling cells.

Dysregulated NUB1 and Neddylation Enhances Rheumatoid Arthritis Fibroblast-Like Synoviocyte Inflammatory Responses.

Fibroblast-like synoviocytes (FLS) contribute to the pathogenesis of rheumatoid arthritis (RA), in part due to activation of the proinflammatory transcription factor NF-κB. Neddylation is modulated by the negative regulator of ubiquitin-like protein (NUB) 1. We determined whether NUB1 and neddylation are aberrant in the models with RA FLS, thereby contributing to their aggressive phenotype. Models with RA or osteoarthritis (OA) FLS were obtained from arthroplasty synovia. Real-time quantitative polymerase chain reaction and Western blot analysis assessed gene and protein expression, respectively. NUB1 was overexpressed using an expression vector. NF-κB activation was assessed by stimulating FLS with interleukin (IL)-1β. Neddylation inhibitor (MLN4924) and proteasome inhibitor were used in migration and gene expression assays. MLN4924 was used in the model with K/BxN serum-transfer arthritis. Enhanced H3K27ac and H3K27me3 peaks were observed in the NUB1 promoter in the OA FLS compared with the RA FLS. NUB1 was constitutively expressed by FLS, but induction by IL-1β was significantly greater in the OA FLS. The ratio of neddylated cullin (CUL) 1 to nonneddylated CUL1 was lower in the OA FLS than the RA FLS. NUB1 overexpression decreased NF-κB nuclear translocation and IL-6 messenger RNA (mRNA) in IL-1β-stimulated the RA FLS. MLN4924 decreased CUL1 neddylation, NF-κB nuclear translocation, and IL-6 mRNA in IL-1β-stimulated the RA FLS. MLN4924 significantly decreased arthritis severity in the model with K/BxN serum-transfer arthritis. CUL1 neddylation and NUB1 induction is dysregulated in the models with RA, which increases FLS activation. Inhibition of neddylation is an effective therapy in an animal model of arthritis. These data suggest that the neddylation system contributes to the pathogenesis of RA and that regulation of neddylation could be a novel therapeutic approach.

MSC-derived small extracellular vesicles mitigate diabetic retinopathy by stabilizing Nrf2 through miR-143-3p-mediated inhibition of neddylation

Diabetic retinopathy (DR) is a highly hazardous and widespread complication of diabetes mellitus (DM). The accumulated reactive oxygen species (ROS) play a central role in DR development. The aim of this research was to examine the impact and mechanisms of mesenchymal stem cell (MSC)-derived small extracellular vesicles (sEV) on regulating ROS and retinal damage in DR. Intravitreal injection of sEV inhibited Cullin3 neddylation, stabilized Nrf2, decreased ROS, reduced retinal inflammation, suppressed Müller gliosis, and mitigated DR. Based on MSC-sEV miRNA sequencing, bioinformatics software, and dual-luciferase reporter assay, miR-143-3p was identified to be the key effector for MSC-sEV's role in regulating neural precursor cell expressed developmentally down-regulated 8 (NEDD8)-mediated neddylation. sEV were able to be internalized by Müller cells. Compared to advanced glycation end-products (AGEs)-induced Müller cells, sEV coculture decreased Cullin3 neddylation, activated Nrf2 signal pathway to combat ROS-induced inflammation. The barrier function of endothelial cells was impaired when endothelial cells were treated with the supernatant of AGEs-induced Müller cells, but was restored when treated with supernatant of AGEs-induced Müller cells cocultured with sEV. The protective effect of sEV was, however, compromised when miR-143-3p was inhibited in sEV. Moreover, the protective efficacy of sEV was diminished when NEDD8 was overexpressed in Müller cells. These findings showed MSC-sEV delivered miR-143-3p to inhibit Cullin3 neddylation, stabilizing Nrf2 to counteract ROS-induced inflammation and reducing vascular leakage. Our findings suggest that MSC-sEV may be a potential nanotherapeutic agent for DR, and that Cullin3 neddylation could be a new target for DR therapy.

Abstract 4503: Preclinical characterization of PRT7732: A highly potent, selective, and orally bioavailable targeted protein degrader of SMARCA2

Abstract SWI/SNF (BAF) complexes play an important role in controlling gene expression by remodeling chromatin. SMARCA2 (BRM) and SMARCA4 (BRG1) are the core catalytic subunits of the SWI/SNF complexes, containing an ATPase domain and a bromodomain. SMARCA4 protein expression is lost in some cancers due to loss-of-function (LOF) mutations and homozygous deletions, and SMARCA4-deleted cancer cells are highly dependent on its paralog gene SMARCA2 for their survival. Therefore, targeting SMARCA2 in SMARCA4-deficient cancers using selective SMARCA2 degraders induces synthetic lethality while sparing SMARCA4 wild type (WT) normal cells. We have recently identified a series of orally bioavailable SMARCA2 selective degraders that demonstrate robust efficacy in pre-clinical animal models with favorable pharmacokinetic properties and safety profiles. Our nomination candidate PRT7732 exhibits >1000x selectivity for SMARCA2 over SMARCA4 in cell-based assays, with DC50 values in cancer cell lines in the low nanomolar range. The PRT7732-induced SMARCA2 degradation was rescued by a proteasome inhibitor and neddylation inhibitor, indicating ubiquitin-proteasome dependent degradation. Furthermore, PRT7732 does not change levels of known CRBN ligand neo-substrates such as IKZF2/3, GSPT1 and SALL4. PRT7732 inhibits only SMARCA4-deficient cancer cell proliferation with IC50 values ranging from 5.0-50 nM, but not SMARCA4 WT cells in vitro. Oral administration of PRT7732 resulted in near-total degradation of SMARCA2 protein with complete selectivity over SMARCA4 protein in a SMARCA4 WT lung cancer model in mice, consistent with the SMARCA2 degradation kinetics-based pharmacodynamic prediction model. PRT7732 oral daily administration showed significant tumor growth inhibition of SMARCA4-deficient lung cancer xenograft models at well tolerated doses. The treated tumor tissues show robust SMARCA2 protein reduction for 24h post dosing. In summary, our orally bioavailable SMARCA2 degraders induce synthetic lethality in SMARCA4-deficient cancers in vitro and in vivo. Efforts to further evaluate these compounds in additional models and in combination with other agents are ongoing. Citation Format: Artem Shvartsbart, Koichi Ito, Joseph Rager, Michael Hulse, Anjana Agarwal, Komali Vykuntam, Jessica Burtell, Min Wang, Justin Kurian, Miles Cowart, Joy Cote, Nick Stahl, Monisha Sivakumar, Anthony Reichelderfer, Jack Carter, Alexander Grego, Andrew Moore, Neha Bhagwat, Ross Kuskovsky, Shanthi Ganesan, Stefan Ruepp, Tom Emm, Philip Pitis, Corey Basch, Klare Bersch, Yongchun Pan, Song Mei, Raul Leal, John Rose, Dani Roth, Chaoyi Xu, Ganfeng Cao, Kris Vaddi, Sang Hyun Lee, Sandy Geeganage, Andrew Combs, Peggy Scherle. Preclinical characterization of PRT7732: A highly potent, selective, and orally bioavailable targeted protein degrader of SMARCA2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4503.

Abstract 2130: Glioblastoma-derived extracellular vesicle cargo as a reporter of drug delivery and effect

Abstract The selectivity of the blood-brain-barrier (BBB) can prevent therapeutics from reaching the brain, and this may contribute to the high failure rate of new drugs for tumors like glioblastoma (GBM) and brain metastasis. The capacity to detect BBB penetrance in real-time in a noninvasive manner would arguably aid the rate of therapeutic development. Extracellular vesicles, which are membrane bound particles secreted by all cell types in the body, have potential as a neuro pharmacodynamic reporter given that their protein and RNA cargo reflect the originating cell population. We hypothesized that the exposure of GBM cells to therapy results in altered EV cargo, and that the detection of this shift can be leveraged as a liquid biopsy from patients during early clinical trials to determine BBB penetrance and tumor engagement. To identify cargo shifts indicative of treatment, we exposed four short-term patient derived glioma cell lines to arsenic trioxide (an idiopathic toxin), MLN4924 (a neddylation inhibitor), and the alkylating agent temozolomide, then harvested EVs for unbiased mass spectrometry and RNA sequencing. Interestingly, we identified conserved upregulated and downregulated protein and RNA species across cell lines and across drug treatments, despite the diverse mechanisms of action. Candidate proteins were further validated by mesoscale immunoassays and exoview evaluation of tetraspanin-captured EVs. RNA species were validated by qRT-PCR. Overall, we demonstrate that GBM-derived EV cargo changes in response to therapy, supporting the development of EVs as a reporter of drug delivery in GBM. Ongoing and future work is focused on identifying enrichment handles in order to selectively evaluate GBM-derived EV cargo from patient biofluids. Thus far, B7H3, PTPRZ1, EGFRvII and IL13Ra2 have been screened as putative handles. Success in this pursuit could substantially enhance findings and accelerate drug testing in early-stage clinical trials in brain tumor patients by reporting drug accessibility to the tumor and engagement with drug targets. Citation Format: Valerie DeLuca, Nanyun Tang, Nathaniel Hansen, Anjali Raju, Charles Shaffer, Yue Hao, Terry C. Burns, Jann N. Sarkaria, Ian Parney, Patrick Pirrotte, Kendall Van Keuren-Jensen, Michael E. Berens. Glioblastoma-derived extracellular vesicle cargo as a reporter of drug delivery and effect [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2130.

Abstract 3882: Targeted degradation of undruggable proteins using a novel heterobifunctional proteomimetic platform

Abstract Of the ~20,000 unique proteins in the human genome, only a subset can be modulated via traditional pharmacological approaches. “Undruggable” targets currently include proteins with pivotal roles in cancer pathogenesis. Our work aims to introduce a new paradigm for engaging these clinically relevant proteins using a modular platform we term the HYbrid DegRAding Copolymers (HYDRACs). HYDRACs multiplex targeting warheads with degradation inducers and have long circulation times plus high cell uptake. Preliminary studies on MYC and RAS, targets of immense pharmaceutical interest, highlight the potential of this platform to revolutionize drug design. Methods: HYDRACs containing MYC- or RAS- targeting peptides randomly copolymerized with degrons were synthesized using ROMP. Fluorescent and biotin-tags were incorporated for use in uptake and pull-down assays. Viability following treatment with MYC-HYDRACs was performed in multiple cell lines with both cellular (MYC-independent lines) and polymer composition controls. Target engagement was assessed via immunoprecipitation and circular dichroism with protein degradation monitored by WB. Unbiased whole proteome analysis and RNAseq were done to confirm observed effects were selectively on-target. In vivo efficacy and biodistribution was assessed in tumor-bearing mice. Results: HYDRACs show high levels of cell uptake and antiproliferative effects at sub-micromolar concentrations in a formulation- and target-dependent manner. Cells treated with MYC-HYDRACs displayed reduced MYC protein levels, which were rescued by proteasome or neddylation inhibition. Swapping out the degron for various validated E3 ligase recruiters maintained MYC degradation, highlighting the “plug-and-play” nature of this approach. On-target activity was confirmed via RNAseq. Biophysical analysis showed strong HYDRAC-protein interactions, orthogonally supported by the presence of target protein following pull-down of biotin-terminated HYDRACs. Target protein degradation only occurred following treatment with an intact HYDRAC compound. Mice bearing MYC-CaP tumors showed delayed tumor growth following treatment with MYC-HYDRACs, with compound accumulation in the tumor for up to 72 h following a single injection. Generalizability was demonstrated against RAS, with RAS-HYDRACs capable of degrading KRAS across multiple different alleles, acting as a pan-KRAS degrader. Conclusions: We present a novel platform technology that addresses the challenges inherent to peptide delivery approaches. HYDRACs have the potential to dramatically alter the drug discovery landscape, allowing for the development of cancer-relevant target modulators for which there are no current viable therapies. We envision the HYDRAC platform as a generalizable approach to designing degraders of proteins of interest, greatly expanding the therapeutic armamentarium for TPD. Citation Format: Max Wang, Mihai Truica, Brayley Gattis, Xiaoyu Zhang, Sarki Abdulkadir, Nathan Gianneschi. Targeted degradation of undruggable proteins using a novel heterobifunctional proteomimetic platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3882.