Protein Tyrosine Phosphatase Non-receptor Type Research Articles

Structural analysis of the FERM domain of human protein tyrosine phosphatase non-receptor type 21.

Protein tyrosine phosphatase non-receptor type 21 (PTPN21) is a cytosolic protein tyrosine phosphatase that regulates cell growth and invasion. Due to its oncogenic properties, PTPN21 has recently emerged as a potential therapeutic target for cancer. In this study, the three-dimensional structure of the PTPN21 FERM domain was determined at 2.1 Å resolution by X-ray crystallography. The crystal structure showed that this domain harbors canonical FERM folding and consists of three subdomains that are tightly packed via highly conserved intramolecular hydrophobic interactions. Consistent with this, the PTPN21 FERM domain shares high structural homology with several other FERM domains. Moreover, structural superimposition demonstrated two putative protein-binding sites of the PTPN21 FERM domain, which are presumed to be associated with interaction with its binding partner, kinesin family member 1C. Thus, these data suggest that the FERM domain of PTPN21 serves as a module that mediates protein-protein interaction, like other FERM domains.

The Role of the Immune System in the Course of Hashimoto's Thyroiditis: The Current State of Knowledge.

The process of thyroid autoimmunization develops against the background of genetic predispositions associated with class II human leukocyte antigens (HLA-DR), as well as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), protein tyrosine phosphatase non-receptor type 22 (PTPN22), and forkhead transcription box protein P3 (FOXP3). Environmental factors, such as vitamin D deficiency, Zn, Se, and Mg, as well as infections, chronic stress, pregnancy, smoking, alcohol, medications, intestinal dysbiosis, and malnutrition, also play an important role. The first stage of autoimmunization involves the accumulation of macrophages and dendritic cells, as well as plasma cells. In the second stage, the mutual interactions of individual cells in the immune system lead to a decrease in the level of CD8+ in favor of CD4+, which intensifies the synthesis of T lymphocyte derivatives, especially Th1, Th17, Tfh, and Tc, reducing the level of Treg. Consequently, the number of the anti-inflammatory cytokines IL10 and IL2 decreases, and the synthesis of the pro-inflammatory cytokines IL-2, Il-12, Il-17, IL-21, IL-22, IFN-γ, and TNF-α increases. The latter two especially trigger the pyroptosis process involving the inflammasome. Activation of the inflammasome by IL-β and IL-18 produced by macrophages is one of the mechanisms of pyroptosis in the course of Hashimoto's thyroiditis, involving Gram-negative bacteria and NLRC4. In the next step, the apoptosis of thyroid cells is initiated by the intensification of perforin, granzyme, and proteoglycan synthesis by Tc and NK cells. The current findings raise many possibilities regarding interventions related to the inhibition of pro-inflammatory cytokines and the stimulation of anti-inflammatory cytokines produced by both T and B lymphocytes. Furthermore, since there is currently no effective method for treating thyroid autoimmunity, a summary of the review may provide answers regarding the treatment of not only Hashimoto's thyroiditis, but also other autoimmune diseases associated with autoimmunity.

MRNA-Lipid Nanoparticle-Mediated Restoration of PTPN14 Exhibits Antitumor Effects by Overcoming Anoikis Resistance in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) poses a challenging prognosis due to early metastasis driven by anoikis resistance. Identifying crucial regulators to overcome this resistance is vital for improving patient outcomes. In this study, a genome-wide CRISPR/Cas9 knockout screen in TNBC cells has identified tyrosine-protein phosphatase nonreceptor type 14 (PTPN14) as a key regulator of anoikis resistance. PTPN14 expression has shown a progressive decrease from normal breast tissue to metastatic tumors. Overexpressing PTPN14 has induced anoikis and inhibited cell proliferation in TNBC cells, while normal human breast cells are unaffected. Mechanistically, PTPN14 is identified as a key factor in dephosphorylating breast cancer antiestrogen resistance 3, a novel substrate, leading to the subsequent inhibition of PI3K/AKT and ERK signaling pathways. Local delivery of in vitro transcribed PTPN14 mRNA encapsulated by lipid nanoparticles in a TNBC mouse model has effectively inhibited tumor growth and metastasis, prolonging survival. The study underscores PTPN14 as a potential therapeutic target for metastatic TNBC, with the therapeutic strategy based on mRNA expression of PTPN14 demonstrating clinical application prospects in alleviating the burden of both primary tumors and metastatic disease.

Tumor microenvironment responsive nano-herb and CRISPR delivery system for synergistic chemotherapy and immunotherapy

Chemoresistance remains a significant challenge for effective breast cancer treatment which leads to cancer recurrence. CRISPR-directed gene editing becomes a powerful tool to reduce chemoresistance by reprogramming the tumor microenvironment. Previous research has revealed that Chinese herbal extracts have significant potential to overcome tumor chemoresistance. However, the therapeutic efficacy is often limited due to their poor tumor targeting and in vivo durability. Here we have developed a tumor microenvironment responsive nanoplatform (H-MnO2(ISL + DOX)-PTPN2@HA, M(I + D)PH) for nano-herb and CRISPR codelivery to reduce chemoresistance. Synergistic tumor inhibitory effects were achieved by the treatment of isoliquiritigenin (ISL) with doxorubicin (DOX), which were enhanced by CRISPR-based gene editing to target protein tyrosine phosphatase non-receptor type 2 (PTPN2) to initiate long-term immunotherapy. Efficient PTPN2 depletion was observed after treatment with M(I + D)PH nanoparticles, which resulted in the recruitment of intratumoral infiltrating lymphocytes and an increase of proinflammatory cytokines in the tumor tissue. Overall, our nanoparticle platform provides a diverse technique for accomplishing synergistic chemotherapy and immunotherapy, which offers an effective treatment alternative for malignant neoplasms.Graphical

Genetic and Epigenetic Etiologies of Type 1 Diabetes Mellitus

Numerous suspect genes associated with type 1 diabetes mellitus (T1DM) have been identified, suggesting a need to focus on the disease's causal genes and mechanisms. This necessitates an update to raise public awareness. This review articulates genes with mutations that predispose individuals to T1DM. We conducted a comprehensive search of academic databases, including Web of Science, Scopus, PubMed, and Google Scholar, for relevant materials. Available information indicates that at least 70 genes are suspected in the pathogenesis of T1DM. However, the most frequently implicated genes include human leukocyte antigen (HLA), insulin (INS), cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), and protein tyrosine phosphatase non-receptor type 22 (PTPN22). Mutations or variants in these genes may lead to insulin insufficiency and, consequently, T1DM by tricking immune cells, such as T-cells and B-cells, into attacking self-antigens and triggering the autoimmunity of beta cells. Furthermore, this pathophysiology can be mediated through aberrant epigenetic modifications, including DNA methylation, histone post-translational modifications, and noncoding RNAs, in the mentioned genes. Some of these pathophysiologies are gene-specific and may have an epigenetic origin that is reversible. In the event of an epigenetic origin, a treatment for T1DM that addresses the causal genes or reverses epigenetic changes and their mechanisms could yield improved outcomes. Medical professionals are encouraged to design therapeutic regimens that specifically target the mentioned genes and address the identified epigenetic alterations in individuals expressing such etiologies.

Imaging Assessment of Fetal Cerebrovascular Anomalies.

Four distinct vascular anomalies can be seen to affect the brain on fetal imaging: vein of Galen malformations, non-galenic arteriovenous pial fistulas, dural sinus malformations, and intracranial venous malformations. These congenital disorders affect the arteries and veins of the developing brain and are rarely seen beyond the neonatal stage. The four fetal cerebrovascular anomalies are associated with quite disparate natural histories and prognoses. MRI plays a pivotal role in the evaluation of fetuses with these conditions due to its ability to definitively establish the diagnosis, to detect subtle parenchymal injuries, to delineate the course of abnormal vessels in detail and to some extent the nature of vascular flow, and to identify ischemic, thrombotic, and hemorrhagic complications. Recently, an investigational transurterine embolization procedure targeted at treating fetuses with vein of Galen malformations who are at high risk for neonatal decompensation has emerged as a promising alternative to expectant management and post-natal embolization, with imaging being used to identify suitable patients for the intervention and in pre-procedural planning. This manuscript reviews the essential imaging and clinical features of these four fetal neurovascular anomalies and underscores the practical aspects related to counseling, prognosis, and the multidisciplinary management of these entities.ABBREVIATIONS: ACVRL1= activin A receptor like type 1; b-SSFP=Balanced Steady State Free precession; DSM= Dural Sinus Malformation; Ephrin B4= Ephrin type-B receptor 4; icVM= Intracranial Venous Malformation; ITGB1= Integrin Subunit Beta 1; NOTCH1= Neurogenic locus notch homolog protein 1; PTPN11= Protein Tyrosine Phosphatase Non-Receptor Type 11; RASA1= RAS P21 Protein Activator 1; SSFSE= Single-shot fast spin echo; VOGM=Vein of Galen Malformation.

Discovery of HDM2010, a highly potent PTPN2 inhibitor for immunotherapy.

e15021 Background: Protein tyrosine phosphatase non-receptor type 2 (PTPN2), a negative regulator of JAK–STAT pathways that plays a crucial role in the immune system, has been identified as a promising target for immunotherapy. Genetic deletion of PTPN2 in either tumor cells or host immune cells promotes the anti-tumor immunity. In addition, PTPN2 inhibitors, alone or in combination with anti-PD1 therapy, significantly reduced tumor growth and enhanced survival in several subcutaneous tumour models. These findings demonstrate that PTPN2 inhibitors may have clinical benefits for immunotherapy-resistant tumors. Herein, the discovery of a series of novel PTPN2 inhibitors and their implications for immunotherapy are reported. Methods: We have successfully developed a series of small molecule inhibitors that specifically target PTPN2/N1. Molecular design was based on a novel backbone and incorporating both structure-based drug design (SBDD) and computational chemistry techniques. To evaluate the efficacy of our inhibitors, PTPN2 phosphatase activity was monitored using the small-molecule substrate DiFMUP in a fluorescence assay format in vitro. Tumor cells were treated with IFNγ and the cell viability was measured. Pharmacokinetic studies were conducted in mice, with serial blood samples analyzed by liquid chromatography−mass spectrometry (LC−MS)/MS. Pharmacokinetic parameters were calculated by noncompartmental analysis. Results: Based on the co-crystal structure of this target reported and multiple previous research projects, we have designed a multitude of novel compounds with the employment of computer-aided drug design (CADD) and scaffold hopping. Through a comprehensive evaluation of the in vitro and in vivo parameters, we have identified a series of compounds displaying potent PTPN2 inhibition (IC50 < 10 nM). Moreover, the compounds displayed remarkable efficacy in killing tumor cells to IFNγ treatment (IC50 < 100 nM). Artificial intelligence was utilized to conduct assessment and prediction of ADME properties, improving the drug-ability including permeability and physicochemical properties. Currently, a series of compounds demonstrating outstanding potency and good pharmacokinetic profiles, with lower hERG blockage (hERG IC50 > 30 µM), were synthesized and characterized. Among these hit compounds, a leading compound with PTPN2 IC50 = 1.1 nM and tumor cells IC50 = 79.5 nM was identified for further optimization and evaluation. Conclusions: We reported our work on discovering HDM2010, in which a series of potent PTPN2 inhibitors with prominent PK and safety profile were synthesized and characterized. Further optimization including in vivo experiments will lead to a preclinical candidate (PCC) selection.

Melanin-based duplex Cas9 ribonucleoprotein nanomedicine for synergistic phototherapy and immunotherapy

Immune checkpoint blockade (ICB) has shown significant progress in treating triple negative breast cancer (TNBC). However, the standalone effectiveness of ICB is modest, offering patients only slight benefits. In this report, we utilize a hypoxia-responsive duplex genome editing strategy to target tumor cell programmed cell death ligand 1 (PD-L1) and protein tyrosine phosphatase non-receptor type 2 (PTPN2), which is synergized with photothermal therapy (PTT) to amplify the therapeutic effect of TNBC. In our approach, the melanin nanoparticles (MNP) serve as the delivery platform for transporting the CRISPR-CasPTPN2/PD-L1 (Cas-TD) system, which is cross-linked by a hypoxic-sensitive Azo linker and then further modified with tumor homing phenylboronic acid (PBA), resulting in a stimuli-responsive multifunctionality nanotheranostic platform (MPA@Cas-TD@PP). Aided by the guidance of PBA, nanoparticles selectively accumulate at tumor and then disintegrate with enhanced intracellular penetration. Importantly, PTT initiates the immunogenic cell death (ICD), turning the “cold” tumor into a “hot” one, laying the foundation for subsequent ICB. Inhibiting PTPN2 and PD-L1 can synergistically sensitize tumors to immunotherapy, which exhibit magnified immunotherapy effects by increasing activated cytotoxic CD8+ T cells and enhancing interferon-γ (IFN-γ)-mediated effects. In summary, this multifunctional nanotherapeutic platform provides a promising treatment approach for synergistic phototherapy and immunotherapy in TNBC.

Overexpression of PTPN21 promotes proliferation of EGF-stimulated acute lymphoblastic leukemia cells via the MAPK signaling pathways

ABSTRACT Objectives This study aims to investigate the role of excessive Protein Tyrosine Phosphatase Non-Receptor Type 21 (PTPN21) in the proliferation of Acute Lymphoblastic Leukemia (ALL) cells with EGF stimulation. Methods PTPN21 was overexpressed in ALL cell lines by lentiviral transfection. Apoptosis was assayed by Annexin V/7-AAD staining. The proliferation and cell cycle of EGF-treated ALL cells were assessed by MTT and Ki-67/7-AAD staining respectively. The phosphorylation of Src tyrosine kinase and mediators of distinct MAPK pathways were assessed by Western blot. Results Overexpression of PTPN21 had minimal effect on the apoptosis of ALL cells, but significantly promoted the proliferation and cell cycle progression of ALL cells stimulated with EGF. The activity of Src tyrosine kinase and the MAPK pathways was elevated. Inhibition of MAPK pathways by specific inhibitors mitigated this pro-proliferative effect of excessive PTPN21 on EGF-stimulated ALL cells. Conclusion PTPN21 may facilitate ALL progression by promoting cell proliferation via the Src/MAPK signaling pathways.

A novel gain-of-function phosphorylation site modulates PTPN22 inhibition of TCR signaling

Protein tyrosine phosphatase nonreceptor type 22 (PTPN22) is encoded by a major autoimmunity gene and is a known inhibitor of T cell receptor (TCR) signaling and drug target for cancer immunotherapy. However, little is known about PTPN22 posttranslational regulation. Here, we characterize a phosphorylation site at Ser325 situated C terminal to the catalytic domain of PTPN22 and its roles in altering protein function. In human T cells, Ser325 is phosphorylated by glycogen synthase kinase-3 (GSK3) following TCR stimulation, which promotes its TCR-inhibitory activity. Signaling through the major TCR-dependent pathway under PTPN22 control was enhanced by CRISPR/Cas9-mediated suppression of Ser325 phosphorylation and inhibited by mimicking it via glutamic acid substitution. Global phospho-mass spectrometry showed Ser325 phosphorylation state alters downstream transcriptional activity through enrichment of Swi3p, Rsc8p, and Moira domain binding proteins, and next-generation sequencing revealed it differentially regulates the expression of chemokines and T cell activation pathways. Moreover, invitro kinetic data suggest the modulation of activity depends on a cellular context. Finally, we begin to address the structural and mechanistic basis for the influence of Ser325 phosphorylation on the protein's properties by deuterium exchange mass spectrometry and NMR spectroscopy. In conclusion, this study explores the function of a novel phosphorylation site of PTPN22 that is involved in complex regulation of TCR signaling and provides details that might inform the future development of allosteric modulators of PTPN22.

Human T-cell lymphotropic virus type 1 (HTLV-1) grip on T-cells: investigating the viral tapestry of activation

IntroductionHuman T-cell Lymphotropic virus type 1 (HTLV-1) belongs to retroviridae which is connected to two major diseases, including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and Adult T-cell leukemia/lymphoma (ATLL). This study aims to investigate the mRNA expressions of key proteins correlated to T-cell activation in asymptomatic carriers (ACs) HTLV-1 infected patients, shedding light on early molecular events and T-cell activation following HTLV-1 infection.Material and MethodsThe study involved 40 participants, including 20 ACs and 20 healthy subjects. Blood samples were collected, ELISA assessment for screening and confirmation with PCR for Trans-activating transcriptional regulatory protein (Tax) and HTLV-1 basic leucine zipper factor (HBZ) of the HTLV-1 were done. mRNA expressions of C-terminal Src kinase (CSK), Glycogen Synthase Kinase-3 Beta (GSK3β), Mitogen-Activated Protein Kinase 14 (MAP3K14 or NIK), Phospholipase C Gamma-1 (PLCG1), Protein Tyrosine Phosphatase non-Receptor Type 6 (PTPN6) and Mitogen-Activated Protein Kinase Kinase Kinase-7 (SLP-76) and Mitogen-Activated Protein Kinase14 (MAP3K7 or TAK1) were assayed using RT-qPCR. Statistical analyses were performed using PRISM and SPSS software.ResultsWhile there were no significant upregulation in CSK and PTPN6 in ACs compared to healthy individuals, expression levels of GSK3β, MAP3K14, PLCG1, SLP-76, and TAK1 were significantly higher in ACs compared to healthy subjects which directly contributes to T-cell activation in the HTLV-1 ACs.ConclusionHTLV-1 infection induces differential mRNA expressions in key proteins associated with T-cell activation. mRNAs related to T-cell activation showed significant upregulation compared to PTPN6 and CSK which contributed to T-cell regulation. Understanding these early molecular events in ACs may provide potential markers for disease progression and identify therapeutic targets for controlling viral replication and mitigating associated diseases. The study contributes novel insights to the limited literature on T-cell activation and HTLV-1 pathogenesis.

Experience-dependent MAPK/ERK signaling in glia regulates critical period remodeling of synaptic glomeruli

Early-life critical periods allow initial sensory experience to remodel brain circuitry so that synaptic connectivity can be optimized to environmental input. In the Drosophila juvenile brain, olfactory sensory neuron (OSN) synaptic glomeruli are pruned by glial phagocytosis in dose-dependent response to early odor experience during a well-defined critical period. Extracellular signal-regulated kinase (ERK) separation of phases-based activity reporter of kinase (SPARK) biosensors reveal experience-dependent signaling in glia during this critical period. Glial ERK-SPARK signaling is depressed by removal of Draper receptors orchestrating glial phagocytosis. Cell-targeted genetic knockdown of glial ERK signaling reduces olfactory experience-dependent glial pruning of the OSN synaptic glomeruli in a dose-dependent mechanism. Noonan Syndrome is caused by gain-of-function mutations in protein tyrosine phosphatase non-receptor type 11 (PTPN11) inhibiting ERK signaling, and a glial-targeted patient-derived mutation increases experience-dependent glial ERK signaling and impairs experience-dependent glial pruning of the OSN synaptic glomeruli. We conclude that critical period experience drives glial ERK signaling that is required for dose-dependent pruning of brain synaptic glomeruli, and that altered glial ERK signaling impairs this critical period mechanism in a Noonan Syndrome disease model.

Protein tyrosine phosphatase 1B (PTP1B) function, structure, and inhibition strategies to develop antidiabetic drugs.

Tyrosine protein phosphatase non-receptor type 1 (PTP1B; also known as protein tyrosine phosphatase 1B) is a member of the protein tyrosine phosphatase (PTP) family and is a soluble enzyme that plays an essential role in different physiological processes, including the regulation of metabolism, specifically in insulin and leptin sensitivity. PTP1B is crucial in the pathogenesis of type 2 diabetes mellitus and obesity. These biological functions have made PTP1B validated as an antidiabetic and anti-obesity, and potentially anticancer, molecular target. Four main approaches aim to inhibit PTP1B: orthosteric, allosteric, bidentate inhibition, and PTPN1 gene silencing. Developing a potent and selective PTP1B inhibitor is still challenging due to the enzyme's ubiquitous expression, subcellular location, and structural properties. This article reviews the main advances in the study of PTP1B since it was first isolated in 1988, as well as recent contextual information related to the PTP family to which this protein belongs. Furthermore, we offer an overview of the role of PTP1B in diabetes and obesity, and the challenges to developing selective, effective, potent, bioavailable, and cell-permeable compounds that can inhibit the enzyme.

Myeloid Ptpn2 Deficiency in Mice Causes Functional Iron Deficiency

Background: Anemia is the most prevalent extraintestinal complication of inflammatory bowel disease (IBD) and is associated with the manifestation of Crohn’s disease. Anemia significantly reduces the quality of life, increases hospitalization visits, and increases medical care expenses of IBD patients. Iron deficiency is the leading cause of anemia in IBD; however, the physiological mechanisms involved are still poorly understood. Macrophages significantly contribute to iron homeostasis by mechanisms including iron recycling by phagocytosing senescent erythrocytes and damaged cells, and nurturing erythropoiesis in the bone marrow. In this study, we investigated the role of the IBD candidate gene, protein tyrosine phosphatase non-receptor type 2 ( PTPN2), in regulating macrophage iron homeostasis. Methods: Myeloid cell-specific knockout mice ( Ptpn2LysMCre) and control littermates ( Ptpn2fl/fl) were analyzed for serum iron content and liver and spleen non-heme iron. Duodenal epithelial cell (DEC) proteins were assayed by Western blotting. Localization of the brush border ferrous iron transporter, DMT1, and the coupled ferrous iron absorption driver, NHE3, in duodenal tissue was determined by immunohistochemistry (IHC). Gene expression profiles of macrophages were analyzed by Nanostring. Results: Ptpn2LysMCre mice had reduced serum iron ( p<0.0001; n=12) and reduced spleen non-heme iron (p=0.0017; n=6), whereas liver non-heme iron was unaltered (n=6), indicating iron deficiency in select tissues. DMT1 (n=8) and NHE3 (n=5) protein expression in DECs was unaltered and IHC confirmed the unaltered localization of DMT1 and NHE3 (n=6) in the duodenal epithelium of Ptpn2LysMCre mice, suggesting the reduction in serum iron was not due to an impairment in intestinal non-heme iron uptake. Nanostring analyses revealed that the gene expression of the iron transporter Dmt1, iron exporter Fpn, and iron importer Tfr1 were significantly downregulated (p<0.05; n=5) in macrophages from Ptpn2LysMCre mice, indicating an iron sequestering phenotype. Conclusions: Loss of myeloid Ptpn2 in mice causes functional iron deficiency. These findings indicate a major role of myeloid PTPN2 in regulating systemic iron homeostasis. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A genome-wide association study identified PTPN2 as a population-specific susceptibility gene locus for primary biliary cholangitis.

Previous genome-wide association studies (GWAS) have indicated the involvement of shared (population-nonspecific) and nonshared (population-specific) susceptibility genes in the pathogenesis of primary biliary cholangitis (PBC) among European and East-Asian populations. Although a meta-analysis of these distinct populations has recently identified more than 20 novel PBC susceptibility loci, analyses of population-specific genetic architecture are still needed for a more comprehensive search for genetic factors in PBC. Protein tyrosine phosphatase nonreceptor type 2 ( PTPN2) was identified as a novel PBC susceptibility gene locus through GWAS and subsequent genome-wide meta-analysis involving 2181 cases and 2699 controls from the Japanese population (GWAS-lead variant: rs8098858, p = 2.6 × 10 -8 ). In silico and in vitro functional analyses indicated that the risk allele of rs2292758, which is a primary functional variant, decreases PTPN2 expression by disrupting Sp1 binding to the PTPN2 promoter in T follicular helper cells and plasmacytoid dendritic cells. Infiltration of PTPN2-positive T-cells and plasmacytoid dendritic cells was confirmed in the portal area of the PBC liver by immunohistochemistry. Furthermore, transcriptomic analysis of PBC-liver samples indicated the presence of a compromised negative feedback loop in vivo between PTPN2 and IFNG in patients carrying the risk allele of rs2292758. PTPN2 , a novel susceptibility gene for PBC in the Japanese population, may be involved in the pathogenesis of PBC through an insufficient negative feedback loop caused by the risk allele of rs2292758 in IFN-γ signaling. This suggests that PTPN2 could be a potential molecular target for PBC treatment.

PTPN7 mediates macrophage-polarization and determines immunotherapy in gliomas: A single-cell sequencing analysis.

Protein tyrosine phosphatase non-receptor type 7 (PTPN7) is a signaling molecule that regulates a multitude of cellular processes, spanning cell proliferation, cellular differentiation, the mitotic cycle, and oncogenic metamorphosis. However, the characteristic of PTPN7 in the glioma microenvironment has yet to be elucidated. The prognostic value, genomic features, immune characteristics, chemotherapy prediction, and immunotherapy prediction of PTPN7 were systematically explored at the bulk sequencing level. The cell evolution trajectory, cell communication pattern, and cell metabolic activity related to PTPN7 were systematically explored at the single-cell sequencing level. HMC3 and M0 cells were cocultured with U251 and T98G cells, and flow cytometry was carried out to investigate the polarization of HMC3 and M0. Transwell assay and CCK-8 assay were performed to explore the migration and proliferation activity of U251 and T98G. The expression level of PTPN7 is significantly elevated in glioma and indicates malignant features. PTPN7 expression predicts worse prognosis of glioma patients. PTPN7 is associated with genome alteration and immune infiltration. Besides, PTPN7 plays a crucial role in modulating metabolic and immunogenic processes, particularly by influencing the activity of microglia and macrophages through multiple signaling pathways involved in cellular communication. Specifically, PTPN7 actively mediates inflammation-resolving-polarization of macrophages and microglia and protects glioma from immune attack. PTPN7 could also predict the response of immunotherapy. PTPN7 is critically involved in inflammation-resolving-polarization mediated by macrophage and microglia and promotes the immune escape of glioma cells.

Abstract 5306: PTPN22 targeting partners with 41BB/OX40 costimulation to overcome anti-PD1 resistance in pancreatic ductal adenocarcinoma

Abstract Background: The pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME) is notable for a scarcity of cytotoxic T cells and an overabundance of immunosuppressive myeloid and regulatory T cells. Checkpoint immunotherapies targeting PD/L1 or CTLA4 have shown efficacy in immunogenic cancers but remain ineffective in PDAC, highlighting a need for novel approaches. Abrogating protein tyrosine phosphatase non-receptor type 22 (PTPN22), a phosphatase in the TCR signaling cascade, has been shown to modulate multiple mechanisms of immune resistance. Furthermore, 41BB costimulatory pathway has recently been investigated as a potential strategy to enhance immunotherapy against PDAC. Using immune-resistant murine models of PDAC, we investigated PTPN22 as an immunotherapeutic target in combination with 41BB co-stimulation and PD1 inhibition against PDAC. Methods: We employed a well-characterized murine PDAC cell line expressing mutant KrasG12D and Trp53R172H under the Pdx1-cre promoter (KPCY 6419c5). This tumor line is resistant to combination immuno- and chemotherapies. To determine treatment efficacy, PTPN22 deficient mice (KO) were inoculated with KPCY6419c5 cells either subcutaneously or orthotopically into the pancreas. To extend the translatability of PTPN22 targeting, we also injected PTPN22 competent mice with the same tumor cells and treated them with our novel PTPN22 inhibitor L1. Harvested tumors were processed for FFPE and mass cytometry (CyTOF) analysis to track changes in the immune compartment. Results: When PTPN22 was abrogated, treatment with anti-PD1 and 41BB agonism led to a 10-day delay in substantial tumor formation and roughly 75% reduction in tumor volume by 21-days post treatment. These tumors showed elevated levels of OX40 and OX40L primarily in the setting of PTPN22 KO/PD1/41BB therapy. In a subsequent in vivo experiment using an OX40L neutralizing antibody, we found that OX40 signaling is essential for the efficacy of PTPN22 KO/PD1/41BB therapy. Furthermore, combining OX40 agonist with anti-PD1 in PTPN22 KO sufficiently mimicked the efficacy seen with the anti-PD-1 and 41BB combination. CyTOF analysis indicated that OX40 expression is enriched in Tregs and OX40L is enriched in myeloid derived suppressor cells (MDSCs). Moreover, combination therapy efficacy was reproduced using the PTPN22 inhibitor L1. Conclusions: PTPN22 abrogation enhances the success of PD-1 inhibition given with either OX-40 or 41BB agonist therapies. In addition, PTPN22 abrogation together with PD1 inhibition and 41BB costimulation reduces MDSC and Treg suppression of effector T cells via the OX40L-OX40 axis. Finally, PTPN22 can be blocked by a small molecule inhibitor strengthening its candidacy as a therapeutic target. Citation Format: Soren Charmsaz, Nicole E. Gross, Jae W. Lee, Jianping Lin, Alexei G. Hernandez, Erin M. Coyne, Sarah M. Shin, Courtney Cannon, Xuan Yuan, Zhong-Yin Zhang, Elizabeth M. Jaffee, Won Jin Ho. PTPN22 targeting partners with 41BB/OX40 costimulation to overcome anti-PD1 resistance in pancreatic ductal adenocarcinoma [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 5306.

5-AZA Upregulates SOCS3 and PTPN6/SHP1, Inhibiting STAT3 and Potentiating the Effects of AG490 against Primary Effusion Lymphoma Cells.

Epigenetic modifications, including aberrant DNA methylation occurring at the promoters of oncogenes and oncosuppressor genes and histone modifications, can contribute to carcinogenesis. Aberrant methylation mediated by histone methylatransferases, alongside histones, can affect methylation of proteins involved in the regulation of pro-survival pathways such as JAK/STAT and contribute to their activation. In this study, we used DNA or histone demethylating agents, 5-Azacytidine (5-AZA) or DS-3201 (valemetostat), respectively, to treat primary effusion lymphoma (PEL) cells, alone or in combination with AG490, a Signal transducer and activator of transcription 3 (STAT3) inhibitor. Cell viability was investigated by trypan blue assay and FACS analysis. The molecular changes induced by 5-AZA and/or AG490 treatments were investigated by Western blot analysis, while cytokine release by PEL cells treated by these drugs was evaluated by Luminex. Statistical analyses were performed with Graphpad Prism® software (version 9) and analyzed by Student's t test or a nonparametric one-way ANOVA test. The results obtained in this study suggest that 5-AZA upregulated molecules that inhibit STAT3 tyrosine phosphorylation, namely Suppressor of Cytokine Signaling 3 (SOCS3) and tyrosine-protein phosphatase non-receptor type (PTPN) 6/Src homology region 2 domain-containing phosphatase-1 (SHP-1), reducing STAT3 activation and downregulating several STAT3 pro-survival targets in PEL cells. As this lymphoma is highly dependent on the constitutive activation of STAT3, 5-AZA impaired PEL cell survival, and when used in combination with AG490 JAK2/STAT3 inhibitor, it potentiated its cytotoxic effect. Differently from 5-AZA, the inhibition of the EZH1/2 histone methyltransferase by DS-3201, reported to contribute to STAT3 activation in other cancers, slightly affected STAT3 phosphorylation or survival in PEL cells, either alone or in combination with AG490. This study suggests that 5-AZA, by upregulating the expression level of SOCS3 and PTPN6/SHP1, reduced STAT3 activation and improved the outcome of treatment targeting this transcription factor in PEL cells.

PTPN11/Corkscrew Activates Local Presynaptic Mapk Signaling to Regulate Synapsin, Synaptic Vesicle Pools, and Neurotransmission Strength, with a Dual Requirement in Neurons and Glia.

Cytoplasmic protein tyrosine phosphatase nonreceptor type 11 (PTPN11) and Drosophila homolog Corkscrew (Csw) regulate the mitogen-activated protein kinase (MAPK) pathway via a conserved autoinhibitory mechanism. Disease-causing loss-of-function (LoF) and gain-of-function (GoF) mutations both disrupt this autoinhibition to potentiate MAPK signaling. At the Drosophila neuromuscular junction glutamatergic synapse, LoF/GoF mutations elevate transmission strength and reduce activity-dependent synaptic depression. In both sexes of LoF/GoF mutations, the synaptic vesicles (SV)-colocalized synapsin phosphoprotein tether is highly elevated at rest, but quickly reduced with stimulation, suggesting a larger SV reserve pool with greatly heightened activity-dependent recruitment. Transmission electron microscopy of mutants reveals an elevated number of SVs clustered at the presynaptic active zones, suggesting that the increased vesicle availability is causative for the elevated neurotransmission. Direct neuron-targeted extracellular signal-regulated kinase (ERK) GoF phenocopies both increased local presynaptic MAPK/ERK signaling and synaptic transmission strength in mutants, confirming the presynaptic regulatory mechanism. Synapsin loss blocks this elevation in both presynaptic PTPN11 and ERK mutants. However, csw null mutants cannot be rescued by wild-type Csw in neurons: neurotransmission is only rescued by expressing Csw in both neurons and glia simultaneously. Nevertheless, targeted LoF/GoF mutations in either neurons or glia alone recapitulate the elevated neurotransmission. Thus, PTPN11/Csw mutations in either cell type are sufficient to upregulate presynaptic function, but a dual requirement in neurons and glia is necessary for neurotransmission. Taken together, we conclude that PTPN11/Csw acts in both neurons and glia, with LoF and GoF similarly upregulating MAPK/ERK signaling to enhance presynaptic Synapsin-mediated SV trafficking.

Abstract B069: Bone marrow-derived adipocytes promote ovarian cancer progression and metastasis

Abstract B069: Bone marrow-derived adipocytes promote ovarian cancer progression and metastasis