Glycoprotein NMB Research Articles

Expression of Potential Antibody-Drug Conjugate Targets in Cervical Cancer.

(1) Background: There is a huge unmet clinical need for novel treatment strategies in advanced and recurrent cervical cancer. Several cell membrane-bound molecules are up-regulated in cancer cells as compared to normal tissue and have revived interest with the introduction of antibody-drug conjugates (ADCs). (2) Methods: In this study, we characterize the expression of 10 potential ADC targets, TROP2, mesotheline, CEACAM5, DLL3, folate receptor alpha, guanylatcyclase, glycoprotein NMB, CD56, CD70 and CD138, on the gene expression level. Of these, the three ADC targets TROP2, CEACAM5 and CD138 were further analyzed on the protein level. (3) Results: TROP2 shows expression in 98.5% (66/67) of cervical cancer samples. CEACAM5 shows a stable gene expression profile and overall, 68.7% (46/67) of cervical cancer samples are CEACAM-positive with 34.3% (23/67) of cervical cancer samples showing at least moderate or high expression. Overall, 73.1% (49/67) of cervical cancer samples are CD138-positive with 38.8% (26/67) of cervical cancer samples showing at least moderate or high expression. (4) Conclusions: TROP2, CEACAM5 or CD138 do seem suitable for further clinical research and the data presented here might be used to guide further clinical trials with ADCs in advanced and recurrent cervical cancer patients.

Fructose regulates the pentose phosphate pathway and induces an inflammatory and resolution phenotype in Kupffer cells

Over-consumption of fructose in adults and children has been linked to increased risk of non-alcoholic fatty liver disease (NAFLD). Recent studies have highlighted the effect of fructose on liver inflammation, fibrosis, and immune cell activation. However, little work summarizes the direct impact of fructose on macrophage infiltration, phenotype, and function within the liver. We demonstrate that chronic fructose diet decreased Kupffer cell populations while increasing transitioning monocytes. In addition, fructose increased fibrotic gene expression of collagen 1 alpha 1 (Col1a1) and tissue metallopeptidase inhibitor 1 (Timp1) as well as inflammatory gene expression of tumor necrosis factor alpha (Tnfa) and expression of transmembrane glycoprotein NMB (Gpnmb) in liver tissue compared to glucose and control diets. Single cell RNA sequencing (scRNAseq) revealed fructose elevated expression of matrix metallopeptidase 12 (Mmp12), interleukin 1 receptor antagonist (Il1rn), and radical S-adenosyl methionine domain (Rsad2) in liver and hepatic macrophages. In vitro studies using IMKC and J774.1 cells demonstrated decreased viability when exposed to fructose. Additionally, fructose increased Gpnmb, Tnfa, Mmp12, Il1rn, and Rsad2 in unpolarized IMKC. By mass spectrometry, C13 fructose tracing detected fructose metabolites in glycolysis and the pentose phosphate pathway (PPP). Inhibition of the PPP further increased fructose induced Il6, Gpnmb, Mmp12, Il1rn, and Rsad2 in nonpolarized IMKC. Taken together, fructose decreases cell viability while upregulating resolution and anti-inflammatory associated genes in Kupffer cells.

Roles of Activin A and Gpnmb in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD).

Metabolic dysfunction-associated steatotic liver disease (MASLD, formerly known as nonalcoholic fatty liver disease (NAFLD)) and metabolic dysfunction-associated steatohepatitis (MASH, formerly known as nonalcoholic steatohepatitis (NASH)) are leading chronic liver diseases, driving cirrhosis, hepatocellular carcinoma, and mortality. MASLD/MASH is associated with increased senescence proteins, including Activin A, and senolytics have been proposed as a therapeutic approach. To test the role of Activin A, we induced hepatic expression of Activin A in a murine MASLD/MASH model. Surprisingly, overexpression of hepatic Activin A dramatically mitigated MASLD, reducing liver steatosis and inflammation as well as systemic fat accumulation, while improving insulin sensitivity. Further studies identified a dramatic decrease in the lipid-associated macrophages (LAM) marker glycoprotein NMB (Gpnmb) by Activin A and Gpnmb knockdown in the same model produced similar benefits and transcriptional changes to Activin A expression. These studies reveal a surprising protective role for Activin A in MASLD and the potential for SASP proteins to have context-specific beneficial effects. Moreover, they implicate both Activin A and Gpnmb as potential therapeutic targets for this condition.

Single-cell transcriptome sequencing–based analysis: probing the mechanisms of glycoprotein NMB regulation of epithelial cells involved in silicosis

Chronic exposure to silica can lead to silicosis, one of the most serious occupational lung diseases worldwide, for which there is a lack of effective therapeutic drugs and tools. Epithelial mesenchymal transition plays an important role in several diseases; however, data on the specific mechanisms in silicosis models are scarce. We elucidated the pathogenesis of pulmonary fibrosis via single-cell transcriptome sequencing and constructed an experimental silicosis mouse model to explore the specific molecular mechanisms affecting epithelial mesenchymal transition at the single-cell level. Notably, as silicosis progressed, glycoprotein non-metastatic melanoma protein B (GPNMB) exerted a sustained amplification effect on alveolar type II epithelial cells, inducing epithelial-to-mesenchymal transition by accelerating cell proliferation and migration and increasing mesenchymal markers, ultimately leading to persistent pulmonary pathological changes. GPNMB participates in the epithelial-mesenchymal transition in distant lung epithelial cells by releasing extracellular vesicles to accelerate silicosis. These vesicles are involved in abnormal changes in the composition of the extracellular matrix and collagen structure. Our results suggest that GPNMB is a potential target for fibrosis prevention.

Gene expression profiling of the masticatory muscle tendons and Achilles tendons under tensile strain in the Japanese macaque Macaca fuscata.

Both Achilles and masticatory muscle tendons are large load-bearing structures, and excessive mechanical loading leads to hypertrophic changes in these tendons. In the maxillofacial region, hyperplasia of the masticatory muscle tendons and aponeurosis affect muscle extensibility resulting in limited mouth opening. Although gene expression profiles of Achilles and patellar tendons under mechanical strain are well investigated in rodents, the gene expression profile of the masticatory muscle tendons remains unexplored. Herein, we examined the gene expression pattern of masticatory muscle tendons and compared it with that of Achilles tendons under tensile strain conditions in the Japanese macaque Macaca fuscata. Primary tenocytes isolated from the masticatory muscle tendons (temporal tendon and masseter aponeurosis) and Achilles tendons were mechanically loaded using the tensile force and gene expression was analyzed using the next-generation sequencing. In tendons exposed to tensile strain, we identified 1076 differentially expressed genes with a false discovery rate (FDR) < 10-10. To identify genes that are differentially expressed in temporal tendon and masseter aponeurosis, an FDR of < 10-10 was used, whereas the FDR for Achilles tendons was set at > 0.05. Results showed that 147 genes are differentially expressed between temporal tendons and masseter aponeurosis, out of which, 125 human orthologs were identified using the Ensemble database. Eight of these orthologs were related to tendons and among them the expression of the glycoprotein nmb and sphingosine kinase 1 was increased in temporal tendons and masseter aponeurosis following exposure to tensile strain. Moreover, the expression of tubulin beta 3 class III, which promotes cell cycle progression, and septin 9, which promotes cytoskeletal rearrangements, were decreased in stretched Achilles tendon cells and their expression was increased in stretched masseter aponeurosis and temporal tendon cells. In conclusion, cyclic strain differentially affects gene expression in Achilles tendons and tendons of the masticatory muscles.

A Multiplex Biomarker Assay Improves the Prediction of Survival in Epithelial Ovarian Cancer.

Epithelial ovarian cancer (EOC) is usually diagnosed in advanced stages and has a high mortality rate. In this study, we used the proximity extension assay from Olink Proteomics to search for new plasma protein biomarkers to predict overall survival (OS) in patients with EOC. Peripheral blood samples were obtained preoperatively from 116 EOC patients undergoing primary debulking surgery: 28 early EOC cases (FIGO stage I-II) and 88 advanced EOC cases (FIGO stage III-IV). Proteins were measured using the Olink Oncology II and Inflammation panels. In total, 177 unique protein biomarkers were analysed. Cross-validation and LASSO regression were combined to select prediction models for OS. The model including age and the three-biomarker combination of neurotrophin-3 (NT-3)+transmembrane glycoprotein NMB (GPNMB)+mesothelin (MSLN) predicted worse OS with AUC=0.79 (p=0.004). Adding cancer antigen 125 (CA125) and human epididymis protein 4 (HE4) to the model further improved performance (AUC=0.83; p=0.003). In a postoperative model including age and stage (III+IV vs. I+II), the three-biomarker panel of chemokine (C-C motif) ligand 28 (CCL28)+T-cell leukaemia/lymphoma protein 1A (TCL1A)+GPNMB improved the prediction of OS (from AUC=0.83 to AUC=0.90; p=0.05). In the postoperative model including age and dichotomized stage (III vs. I+II), the biomarkers CCL28 and GPNMB1 improved the prediction of OS (AUC=0.86; p<0.001). The combination of high levels of both CA125 and HE4 predicted worse survival (p=0.05). In this explorative study evaluating the performance of plasma protein biomarkers in predicting OS, we found that adding biomarkers, especially NT-3, to the panel improved the prediction of OS.

Pleiotropic effect of LRRK2 on Parkinson‐associated proteins and processing of pathological alpha‐synuclein in myeloid cells

AbstractBackgroundMutations in the LRRK2 gene, which encodes leucine‐rich repeat kinase 2 (LRRK2), are a cause of autosomal dominant Parkinson’s disease (PD). Single‐nucleotide polymorphisms (SNP) in the LRRK2 locus are one of the most consistently replicated in multiple genome‐wide association studies in sporadic PD and with inflammatory diseases. We recently found that a PD‐associated risk SNP (rs76904798, p = 2.0×10−28) in the LRRK2 locus is also associated with cerebrospinal fluid (CSF) levels of granulins (PGRN, p = 8.6×10−9), glycoprotein nmb (GPNMB, p = 2.3×10−9), Ectonucleoside triphosphate diphosphohydrolase‐1 (ENTPD1, p = 2.3×10−9) also known as CD39 and Cathepsin B (CTSB, p = 2.5×10−4). Yet, functional validation in cellular models is lacking.MethodsHuman monocytic cells (U937) were differentiated (dU937) into macrophages to test the effect of LRRK2 on CTSB, CD39, GPNMB, PGRN and alpha‐synuclein (aSyn). LRRK2 kinase activity and expression level were modulated using pharmacological inhibitors and lentivirus‐mediated overexpression. Protein levels were assessed using western blotting and ELISA. dU937 cells were treated with human aSyn pre‐formed fibrils (haSyn PFFs). We analyzed CSF somaLogic data from the Parkinson’s Progression Marker’s Initiative (PPMI) cohort (Data accessed November 2021).Results LRRK2 mutation (G2019S and R1441G) carriers from the PPMI cohort exhibit significantly increased CSF levels of PGRN (p = 2.1×10−22), GPNMB (p = 1.6×10−29), CTSB (p = 2.5×10−16) and CD39 (p = 1.8×10−18) compared to age and gender‐matched non‐carriers (N = 1158). dU937 cells overexpressing LRRK2 showed an increase in the phosphorylation of LRRK2‐Ser935 and Rab10‐T73 and intracellular levels of lysosomal proteins CTSB and Saposin D without affecting LAMP1 or M6PR. LRRK2 also reduced extracellular CD39, PGRN and GPNMB levels and the levels of intracellular endogenous aSyn dimers in dU937 cells. HaSyn PFF treatment induced a time‐dependent reduction of CTSB and GPNMB levels, increased PGRN levels and altered intracellular aSyn processing pattern in dU937 cells overexpressing LRRK2. Pharmacological LRRK2 kinase inhibition decreased intracellular CTSB levels. LRRK2 co‐immunoprecipitates with PGRN in cells and in human brain.ConclusionsLRRK2 modifies lysosome‐associated proteins and regulate aSyn proteostasis. Pathogenic LRRK2 mutations increased CSF levels of PGRN, GPNMB, CTSB and CD39 in the PPMI cohort. Our in vivo and in vitro data supports a pleotropic role of the LRRK2 locus as a genetic modifier of PD‐associated proteins.

In this Issue

HomeCirculation ResearchVol. 131, No. 8In this Issue Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIn this Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published29 Sep 2022https://doi.org/10.1161/RES.0000000000000573Circulation Research. 2022;131:651is related toExtracellular Vesicles Regulate Sympatho-Excitation by Nrf2 in Heart FailureImpaired Dynamic Sarcoplasmic Reticulum Ca Buffering in Autosomal Dominant CPVT2is related toTranscriptional and Immune Landscape of Cardiac SarcoidosisCardiac Sarcoidosis Immune Landscape (p 654)Download figureDownload PowerPointLiu et al examine the transcriptional and cellular composition of cardiac sarcoidosis.Sarcoidosis is a rare inflammatory disease in which granulomas—small, localized sites of inflammation—afflict various parts of the body, most commonly the lungs, skin and lymph nodes. While sarcoidosis can be managed, there is no cure for the condition and, if it manifests in the heart, it can be deadly. Because little is known about the specific pathology of cardiac sarcoidosis (CS), and because it can resemble other forms of heart inflammation, Liu and colleagues set out to map the specific transcriptional and cellular landscape of CS lesions. Using a combination of spatial transcriptomics, single-nucleus RNA sequencing and immunofluorescence, the team compared tissue samples from CS patients with those from patients with other types of myocarditis. CS granulomas had a particular cellular arrangement, the team found, with HLA-DR+ macrophages immediately adjacent to and surrounding multinucleated giant cells. The giant cells expressed transmembrane glycoprotein NMB—a novel marker of these cells—while activation of mTOR genes was a feature of the surrounding macrophages. These analyses were carried out on a small number of patient samples but, if further studies validate the findings, they could form the basis of future diagnostic tests for CS, say the team.Impaired Dynamic SR Ca Buffering Causes AD-CPVT2 (p 673)Download figureDownload PowerPointWleklinski et al reveal the molecular effects of a dominant CPVT-causing mutation.Exercise or emotional stress can prompt the release of catecholamine hormones, which induce a fast heart rate, increased blood pressure and other features of the fight-or-flight response. For people with catecholaminergic polymorphic ventricular tachycardia (CPVT), however, physical activity or stress can cause potentially lethal arrythmias. Mutation of calsequestrin-2 (CASQ2)—a sarcoplasmic reticulum (SR) calcium binding protein—is a major cause of CPVT and can be recessive or dominant in nature. For many recessive mutations, disease occurs due to loss of CASQ2 protein. Wleklenski and colleagues have investigated a dominant lysine-to-arginine mutation (K180R) and find, by contrast, protein levels remain normal. In mice carrying the mutation, not only was the level of CASQ2 comparable to that in control animals, but so too was the protein’s subcellular localization. The mutation instead interfered with CASQ2’s calcium binding, or buffering, capability within the SR. The result was that, upon catecholamine injection or exercise, the unbound calcium released prematurely from the SR triggering spontaneous cell contractions. In uncovering this novel molecular etiology of CPVT, the work provides a basis for studying the consequences of other dominant CASQ2 mutations, say the team.EV-Mediated Heart Brain Communication in CHF (p 687)Download figureDownload PowerPointTian et al discover signals from the failing heart to the brain that may further exacerbate cardiac dysfunction.After a myocardial infarction, increased oxidative stress in the heart can contribute to adverse cardiac remodeling and ultimately heart failure. Nrf2 is a master activator of antioxidant genes, suggesting a protective role, but studies in rats have shown its expression to be suppressed after MI—likely due to upregulation of Nrf2-targeting microRNAs. These miRNAs can also be packaged into vesicles and released from stressed heart cells, and now Tian and colleagues show that rats and humans with chronic heart failure (CHF) have an abundance of these miRNA-containing EVs in their blood. In the rats with CHF, these EVs were found to be taken up by neurons of the rostral ventrolateral medulla (RVLM) wherein the miRNAs suppressed Nrf2 expression. The RVLM is a brain region that controls the sympathetic nervous system and, in the presence of the EVs, it ramped up sympathetic excitation. Because such elevated sympathetic activity can induce the fight-or-flight response—including increased heart rate and blood pressure—this would likely worsen heart failure progression. The team found, however, that inhibiting the miRNAs in the EVs prevented Nrf2 suppression in the RVLM and sympathetic activation, suggesting the pathway could be targeted therapeutically. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesExtracellular Vesicles Regulate Sympatho-Excitation by Nrf2 in Heart FailureChanghai Tian, et al. Circulation Research. 2022;131:687-700Impaired Dynamic Sarcoplasmic Reticulum Ca Buffering in Autosomal Dominant CPVT2Matthew J. Wleklinski, et al. Circulation Research. 2022;131:673-686Transcriptional and Immune Landscape of Cardiac SarcoidosisJing Liu, et al. Circulation Research. 2022;131:654-669 September 30, 2022Vol 131, Issue 8 Advertisement Article InformationMetrics © 2022 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000573 Originally publishedSeptember 29, 2022 PDF download Advertisement

Transcriptional and Immune Landscape of Cardiac Sarcoidosis.

Background:Cardiac involvement is an important determinant of mortality among sarcoidosis patients. Although granulomatous inflammation is a hallmark finding in cardiac sarcoidosis, the precise immune cell populations that comprise the granuloma remain unresolved. Furthermore, it is unclear how the cellular and transcriptomic landscape of cardiac sarcoidosis differs from other inflammatory heart diseases.Methods:We leveraged spatial transcriptomics (GeoMx digital spatial profiler) and single-nucleus RNA sequencing to elucidate the cellular and transcriptional landscape of cardiac sarcoidosis. Using GeoMX digital spatial profiler technology, we compared the transcriptomal profile of CD68+ rich immune cell infiltrates in human cardiac sarcoidosis, giant cell myocarditis, and lymphocytic myocarditis. We performed single-nucleus RNA sequencing of human cardiac sarcoidosis to identify immune cell types and examined their transcriptomic landscape and regulation. Using multichannel immunofluorescence staining, we validated immune cell populations identified by single-nucleus RNA sequencing, determined their spatial relationship, and devised an immunostaining approach to distinguish cardiac sarcoidosis from other inflammatory heart diseases.Results:Despite overlapping histological features, spatial transcriptomics identified transcriptional signatures and associated pathways that robustly differentiated cardiac sarcoidosis from giant cell myocarditis and lymphocytic myocarditis. Single-nucleus RNA sequencing revealed the presence of diverse populations of myeloid cells in cardiac sarcoidosis with distinct molecular features. We identified GPNMB (transmembrane glycoprotein NMB) as a novel marker of multinucleated giant cells and predicted that the MITF (microphthalmia-associated transcription factor) family of transcription factors regulated this cell type. We also detected additional macrophage populations in cardiac sarcoidosis including HLA-DR (human leukocyte antigen-DR)+ macrophages, SYTL3 (synaptotagmin-like protein 3)+ macrophages and CD163+ resident macrophages. HLA-DR+ macrophages were found immediately adjacent to GPMMB+ giant cells, a distinct feature compared with other inflammatory cardiac diseases. SYTL3+ macrophages were located scattered throughout the granuloma and CD163+ macrophages, CD1c+ dendritic cells, nonclassical monocytes, and T cells were located at the periphery and outside of the granuloma. Finally, we demonstrate mTOR (mammalian target of rapamycin) pathway activation is associated with proliferation and is selectively found in HLA-DR+ and SYLT3+ macrophages.Conclusions:In this study, we identified diverse populations of immune cells with distinct molecular signatures that comprise the sarcoid granuloma. These findings provide new insights into the pathology of cardiac sarcoidosis and highlight opportunities to improve diagnostic testing.

GPNMB: a potent inducer of immunosuppression in cancer.

The immune system is comprised of both innate and adaptive immune cells, which, in the context of cancer, collectively function to eliminate tumor cells. However, tumors can actively sculpt the immune landscape to favor the establishment of an immunosuppressive microenvironment, which promotes tumor growth and progression to metastatic disease. Glycoprotein-NMB (GPNMB) is a transmembrane glycoprotein that is overexpressed in a variety of cancers. It can promote primary tumor growth and metastasis, and GPNMB expression correlates with poor prognosis and shorter recurrence-free survival in patients. There is growing evidence supporting an immunosuppressive role for GPNMB in the context of malignancy. This review provides a description of the emerging roles of GPNMB as an inducer of immunosuppression, with a particular focus on its role in mediating cancer progression by restraining pro-inflammatory innate and adaptive immune responses.

Glycoprotein NMB promotes tumor formation and malignant progression of laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma (LSCC), although one of the most common head and neck cancers, has a static or slightly decreased survival rate because of difficulties in early diagnosis, lack of effective molecular targeting therapy, and severe dysfunction after radical surgical treatments. Therefore, a novel therapeutic target is crucial to increase treatment efficacy and survival rates in these patients. Glycoprotein NMB (GPNMB), whose role in LSCC remains elusive, is a type 1 transmembrane protein involved in malignant progression of various cancers, and its high expression is thought to be a poor prognostic factor. In this study, we showed that GPNMB expression levels in LSCC samples are significantly higher than those in normal tissues, and GPNMB expression is observed mostly in growth‐arrested cancer cells. Furthermore, knockdown of GPNMB reduces monolayer cellular proliferation, cellular migration, and tumorigenic growth, while GPNMB protein displays an inverse relationship with Ki‐67 levels. Therefore, we conclude that GPNMB may be an attractive target for future LSCC therapy.

Proteomic analysis of alcohol-associated hepatitis reveals glycoprotein NMB (GPNMB) as a novel hepatic and serum biomarker.

Alcohol consumption remains a leading cause of liver disease worldwide, resulting in a complex array of hepatic pathologies, including steatosis, steatohepatitis, and cirrhosis. Individuals who progress to a rarer form of alcohol-associated liver disease (ALD), alcohol-associated hepatitis (AH), require immediate life-saving intervention in the form of liver transplantation. Rapid onset of AH is poorly understood and the metabolic mechanisms contributing to the progression to liver failure remain undetermined. While multiple mechanisms have been identified that contribute to ALD, no cures exist and mortality from AH remains high. To identify novel pathways associated with AH, our group utilized proteomics to investigate AH-specific biomarkers in liver explant tissues. The goal of the present study was to determine changes in the proteome as well as epigenetic changes occurring in AH. Protein abundance and acetylomic analyses were performed utilizing nHPLC-MS/MS, revealing significant changes to proteins associated with metabolic and inflammatory fibrosis pathways. Here, we describe a novel hepatic and serum biomarker of AH, glycoprotein NMB (GPNMB). The anti-inflammatory protein GPNMB was significantly increased in AH explant liver and serum compared to healthy donors by 50-fold and 6.5-fold, respectively. Further, bioinformatics analyses identified an AH-dependent decrease in protein abundance across fatty acid degradation, biosynthesis of amino acids, and carbon metabolism. The greatest increases in protein abundance were observed in pathways for focal adhesion, lysosome, phagosome, and actin cytoskeleton. In contrast with the hyperacetylation observed in murine models of ALD, protein acetylation was decreased in AH compared to normal liver across fatty acid degradation, biosynthesis of amino acids, and carbon metabolism. Interestingly, immunoblot analysis found epigenetic marks were significantly increased in AH explants, including Histone H3K9 and H2BK5 acetylation. The increased acetylation of histones likely plays a role in the altered proteomic profile observed, including increases in GPNMB. Indeed, our results reveal that the AH proteome is dramatically impacted through unanticipated and unknown mechanisms. Understanding the origin and consequences of these changes will yield new mechanistic insight for ALD as well as identify novel hepatic and serum biomarkers, such as GPNMB.

HSP90 inhibitors induce GPNMB cell-surface expression by modulating lysosomal positioning and sensitize breast cancer cells to glembatumumab vedotin.

Transmembrane glycoprotein NMB (GPNMB) is a prognostic marker of poor outcome in patients with triple-negative breast cancer (TNBC). Glembatumumab Vedotin, an antibody drug conjugate targeting GPNMB, exhibits variable efficacy against GPNMB-positive metastatic TNBC as a single agent. We show that GPNMB levels increase in response to standard-of-care and experimental therapies for multiple breast cancer subtypes. While these therapeutic stressors induce GPNMB expression through differential engagement of the MiTF family of transcription factors, not all are capable of increasing GPNMB cell-surface localization required for Glembatumumab Vedotin inhibition. Using a FACS-based genetic screen, we discovered that suppression of heat shock protein 90 (HSP90) concomitantly increases GPNMB expression and cell-surface localization. Mechanistically, HSP90 inhibition resulted in lysosomal dispersion towards the cell periphery and fusion with the plasma membrane, which delivers GPNMB to the cell surface. Finally, treatment with HSP90 inhibitors sensitizes breast cancers to Glembatumumab Vedotin in vivo, suggesting that combination of HSP90 inhibitors and Glembatumumab Vedotin may be a viable treatment strategy for patients with metastatic TNBC.

GPNMB mitigates Alzheimer’s disease and enhances autophagy via suppressing the mTOR signal

Alzheimer’s disease (AD) is a common neurodegenerative disease which is characterized by amyloid beta (Aβ) accumulation. We found that glycoprotein NMB (GPNMB) was highly expressed in the brain of APP/PS1 mice, a mouse model of AD. However, its role in AD remains unclear. In this study, we aimed to explore the function of GPNMB in AD. The expression of GPNMB in the brain was detected by immunofluorescence and western blot. In addition, the role of GPNMB in AD was explored through gain-of-function. Autophagy, which is beneficial to Aβ clearance, was evaluated by transmission electron microscope and immunofluorescence with beclin-1. Furthermore, 3-MA, an autophagy inhibitor, was employed to evidence whether GPNMB reduced the level of Aβ through autophagy. We found that over-expression of GPNMB improved AD-like behaviors in APP/PS1 mice and reduced Aβ deposition. Further study showed that GPNMB enhanced autophagy, reduced microglial cells and inhibited the activation of the mTOR signal. Additionally, treatment with 3-MA abolished the beneficial effect of GPNMB on Aβ clearance. This study revealed that the high level of GPNMB in AD brain may help Aβ clearance and improve AD-like behaviors through enhancing autophagy via suppressing the mTOR signal. This beneficial role of GPNMB provides us novel strategies for the prevention and treatment of AD.

Adaptive resistance in tumors to anti-PD-1 therapy through re-immunosuppression by upregulation of GPNMB expression

Acquired resistance to the antitumor activity of antibodies targeting the programmed death 1 (PD-1): programmed death ligand 1 (PD-L1) immune checkpoint in various types of cancers has increasingly been observed during treatment. To gain insight into the molecular mechanism underlying anti-PD-1 therapy resistance, we developed a mouse MC38 colon adenocarcinoma cell line that was made resistant to anti-PD-1 treatment through repeated in vivo selection. We compared the transcriptomic profiles of anti-PD-1 therapy-resistant and -sensitive tumors using RNA sequencing analysis. The immunosuppressive molecule transmembrane glycoprotein NMB (GPNMB) was significantly upregulated in resistant tumor cells, as determined using quantitative real-time polymerase chain reaction and immunofluorescence analyses. Furthermore, deletion of GPNMB in resistant cells successfully restored sensitivity to anti-PD-1 treatment in vivo. Collectively, our results indicate that tumors may develop resistance to anti-PD-1 therapy by upregulating their expression of the immunosuppressive molecule GPNMB. Furthermore, GPNMB is a potential, targetable biomarker for monitoring adaptive resistance to therapeutic PD-1 blockade, and identification of this immunosuppressive molecule may be a breakthrough for new therapies.

Evaluation of cerebrospinal fluid glycoprotein NMB (GPNMB) as a potential biomarker for Alzheimer\u2019s disease

BackgroundAlzheimer’s disease (AD) is a neurodegenerative disorder associated with extracellular amyloid-β peptide deposition and progressive neuron loss. Strong evidence supports that neuroinflammatory changes such as the activation of astrocytes and microglia cells are important in the disease process. Glycoprotein nonmetastatic melanoma protein B (GPNMB) is a transmembrane glycoprotein that has recently been associated with an emerging role in neuroinflammation, which has been reported to be increased in post-mortem brain samples from AD and Parkinson’s disease patients.MethodsThe present study describes the partial “fit for purpose” validation of a commercially available immunoassay for the determination of GPNMB levels in the cerebrospinal fluid (CSF). We further assessed the applicability of GPNMB as a potential biomarker for AD in two different cohorts that were defined by biomarker-supported clinical diagnosis or by neuroimaging with amyloid positron emission tomography, respectively.ResultsThe results indicated that CSF GPNMB levels could not distinguish between AD or controls with other neurological diseases but correlated with other parameters such as aging and CSF pTau levels.ConclusionsThe findings of this study do not support GPNMB in CSF as a valuable neurochemical diagnostic biomarker of AD but warrant further studies employing healthy control individuals.

Efficacy and Safety of Glembatumumab Vedotin in Patients With Advanced or Metastatic Squamous Cell Carcinoma of the Lung (PrECOG 0504)

IntroductionGlycoprotein NMB is a transmembrane protein linked with poor prognosis and is expressed in most squamous lung cancer. Glembatumumab vedotin is an antibody-drug conjugate targeting glycoprotein NMB, administered intravenously every 3 weeks in this phase 1 study to determine the safety, tolerability, and maximum tolerated dose in patients who had progressed on any number of previous therapies. ResultsA total of 13 patients were enrolled; adverse events (of any grade) including dyspnea, neutropenia, respiratory failure, anemia, increased aspartate transaminase/alanine transaminase, diarrhea, and hypophosphatemia were seen in 15% of patients. Grade 5 events included two cases of respiratory failure, either completely or partially attributed to cancer progression. The only other grade 5 event was “disease progression.” The most common adverse events (23%) were decreased appetite, fatigue, rash, and weight loss.The median overall and progression-free survivals were 5.7 months (90% confidence interval: 2.5–16.8) and 2.5 months (90% confidence interval: 1.6–5.8) respectively. ConclusionsGlembatumumab vedotin exhibited no serious or unexpected toxicity in this heavily pretreated population, except those caused by disease progression. Modest anticancer activity was observed with a recommendation for a phase 2 dose of 1.9 mg/kg. This portion of the study was not undertaken owing to the company’s decision to discontinue drug development.

Proteogenomic analysis of cerebrospinal fluid reveals causal role of proteins from the autophagy‐lysosome pathway in Parkinson’s disease

AbstractBackgroundIntegrating genetic variants associated with protein levels (protein quantitative trait loci; pQTLs) with variants from genome‐wide association studies (GWAS) using Mendelian randomization approaches has uncovered a causal role of previously unsuspected proteins in several diseases. We have successfully applied a combination of targeted proteomic and genomic approaches to the cerebrospinal fluid (CSF) of Alzheimer Disease (AD) patients to identify multiple novel genetic associations. However, there are currently no proteogenomic studies in Parkinson’s Disease (PD).MethodsWe used the SOMAscan 1.3k Assay (∼1,305 SOMAmers) in ∼1015 samples from the ADRC‐WUSTL. SOMAscan data from the Parkinson's Progression Markers Initiative cohort and Sasayama D, et al 2017 were used as replication cohorts. After stringent QC steps were applied to SOMA data, each SOMAmer was log10 transformed and standardized to zero. We used linear additive genetic regression models adjusted for age, sex, genotyping array and the first two principal components using Plink 1.9. We used the R package MendelianRandomization to integrate our CSF pQTL variants with PD‐related SNPs from the 2019 METAPD GWAS.ResultsWe found significant cis‐pQTLs for Cathepsin B (p = 3.6 × 10−27), Alpha‐L‐iduronidase (p = 3.4 × 10−41) and Galactin‐3 (p = 2.7 × 10−41). MR found significant causal associations of PD risk with pQTLs for IDUA (b = 1.2, p = 5.0 × 10−6), CSTB (b = ‐1.4, p = 2.7 × 10−4) and Galactin‐3 (b = ‐1, p = 4.0 × 10−2). Most importantly, we found an association with progranulin (PGRN) trans‐pQTLs (p = 2.5 × 10−9). This association was replicated in the PPMI cohort (p = 1.9 × 10−9), and MR confirmed the significant causal link of PGRN (b = 4.6, p = 1.0 × 10−4) with PD. The PGRN pQTL in CSF is located in the LRRK2 gene locus. This SNP is also associated with the CSF levels of proteins from two additional PD‐associated genes CTSB (p = 1.6 × 10−3) and glycoprotein nmb (GPNMB, p = 1.5 × 10−4).ConclusionOur proteogenomic approach identified LRRK2 as a genetic modifier of three additional PD‐associated proteins in CSF. MR analyses confirmed the causal link of proteins from the autophagy‐lysosome pathway with PD. Our data provide new biological insights into how LRRK2 modifies PD risk and novel markers for screening of LRRK2 kinase activity.

A Phase II Study of Glembatumumab Vedotin for Metastatic Uveal Melanoma.

Glembatumumab vedotin (CDX-011, GV) is a fully human Immunoglobulin G2 monoclonal antibody directed against glycoprotein NMB coupled via a peptide linker to monomethyl auristatin E (MMAE), a potent cytotoxic microtubule inhibitor. This phase II study evaluated the overall response rate and safety of GV, glycoprotein NMB (GPNMB) expression, and survival in patients with metastatic uveal melanoma. Eligible patients with metastatic uveal melanoma who had not previously been treated with chemotherapy received GV 1.9 mg/kg every three weeks. The primary endpoint was the objective response rate (ORR). Secondary endpoints included GPNMB expression, progression-free survival (PFS), overall survival (OS), and toxicity analysis. GPNMB expression was assessed pre- and post-treatment via immunohistochemistry for patients with available tumor tissue. Out of 35 patients who received treatment, two patients had confirmed partial responses (PRs; 6%), and 18 patients had a stable disease (SD; 51%) as the best objective response. 38% of the patients had stable disease >100 days. The grade 3 or 4 toxicities that occurred in two or more patients were neutropenia, rash, hyponatremia, and vomiting. The median progression-free survival was 3.1 months (95% CI: 1.5–5.6), and the median overall survival was 11.9 months (95% CI 9.0–16.9) in the evaluable study population. GV is well-tolerated in metastatic uveal melanoma. The disease control rate was 57% despite a low objective response rate. Exploratory immune correlation studies are underway to provide insight into target saturation, combination strategies, and antigen release.

The soluble glycoprotein NMB (GPNMB) produced by macrophages induces cancer stemness and metastasis via CD44 and IL-33.

In cancer, myeloid cells have tumor-supporting roles. We reported that the protein GPNMB (glycoprotein nonmetastatic B) was profoundly upregulated in macrophages interacting with tumor cells. Here, using mouse tumor models, we show that macrophage-derived soluble GPNMB increases tumor growth and metastasis in Gpnmb-mutant mice (DBA/2J). GPNMB triggersin the cancer cells the formation of self-renewing spheroids, which are characterized by the expression of cancer stem cell markers, prolonged cell survival and increased tumor-forming ability. Through the CD44 receptor, GPNMB mechanistically activates tumor cells to express the cytokine IL-33 and its receptor IL-1R1L. We also determined that recombinant IL-33 binding to IL-1R1L is sufficient to induce tumor spheroid formation with features of cancer stem cells. Overall, our results reveal a new paracrine axis, GPNMB and IL-33, which is activated during the cross talk of macrophages with tumor cells and eventually promotes cancer cell survival, the expansion of cancer stem cells and the acquisition of a metastatic phenotype.