Inhibitory Signaling Pathways Research Articles

A Systematic Review of the Advances in the Study of T Lymphocyte Suppressor Receptors in HBV Infection: Potential Therapeutic Targets.

Background: HBV-specific T lymphocytes are pivotal in eliminating the hepatitis B virus (HBV) and regulating intrahepatic inflammatory reactions. Effective T cell responses curtail HBV infection; however, compromised immunity can result in persistent infection. Beyond the acute phase, the continued presence of antigens and inflammation leads to the increased expression of various inhibitory receptors, such as PD-1, CTLA-4, Tim-3, LAG3, 2B4, CD160, BTLA, and TIGIT. This escalates the dysfunction of and diminishes the immune and proliferative abilities of T cells. Methods: In this study, we reviewed English-language literature from PubMed, Web of Science, and Scopus up to 9 July 2023. This paper aims to elucidate the inhibitory effects of these receptors on HBV-specific T lymphocytes and how immune function can be rejuvenated by obstructing the inhibitory receptor signaling pathway in chronic HBV patients. We also summarize the latest insights into related anti-HBV immunotherapy. Result: From 66 reviewed reports, we deduced that immunotherapy targeting inhibitory receptors on T cells is a reliable method to rejuvenate T cell immune responses in chronic HBV patients. However, comprehensive combination therapy strategies are essential for a functional cure. Conclusions: Targeting T cell suppressor receptors and combining immunotherapy with antiviral treatments may offer a promising approach towards achieving a functional cure, urging future research to prioritize effective combination therapeutic strategies for chronic HBV infection.

In vitro re-challenge of CAR T cells.

Chimeric antigen receptor (CAR) T cells (CAR T) have emerged as a potential therapy for cancer patients. CAR T cells are capable of recognizing membrane proteins on cancer cells which initiates a downstream signaling in T cells that ends in cancer cell death. Continuous antigen exposure over time, activation of inhibitory signaling pathways and/or chronic inflammation can lead to CAR T cell exhaustion. In this context, the design of CARs can have a great impact on the functionality of CAR T cells, on their potency and exhaustion. Here, using CD19CAR as model, we provide a re-challenge protocol where CAR T cells are cultured weekly with malignant lymphoid cell lines BL-41 and Nalm-6 to simulate them with continuous antigen pressure over a four-week period. This protocol can be value for assessing CAR T cell functionality and for the comparison of different CAR constructs.

Antidiabetic Effect of Standardized Chrysanthemum rubellum Hydroethanolic Extract by Targeting α-Glucosidase and the PTP-1B Signaling Pathway for Alleviating Diabetes in Experimental Model.

The study's goal was to find out whether Chrysanthemum rubellum extract has anti-diabetic properties by concentrating on α-glucosidase and the PTP-1B signaling pathway. C. rubellum flowers were used for extraction using Methanol/water (80/20) as solvent. LC-MS techniques was used to check the presence of phytoconstituents present in C. rubellum extract. In vitro antidiabetic activity was evaluated using α-glucosidase inhibitory activity and PTP-1B signaling pathway. On Streptozotocin (STZ)-induced rats with diabetes, the in vivo antidiabetic efficacy was assessed using a test for oral glucose tolerance. The phytoconstituents identified in the extract of C. rubellum were apigenin, diosmin, myricetin, luteolin, luteolin-7-glucoside, and Quercitrin as compound 1-6, respectively. Results showed that diosmin exhibited highest α-glucosidase inhibitory activity i.e. 90.39%. The protein level of PTP-1B was lowered and the insulin signalling activity was directly increased by compounds 1-6. The maximum blood glucose levels were seen in all groups' OGTT findings at 30 minutes following glucose delivery, followed by gradual drops. In comparison to the control group, the extract's glucose levels were 141 mg/dL at 30 minutes before falling to 104 mg/dL after 120 minutes. The current study has demonstrated, in summary, that extract with phytoconstituents reduce blood sugar levels in rats. This finding suggests that extract may reduce the chance of insulin resistance and shield against disorders like hyperglycemia.

Wilforine inhibits rheumatoid arthritis pathology through the Wnt11/β-catenin signaling pathway axis

BackgroundWilforine (WFR) is a monomeric compound of the anti-RA plant Tripterygium wilfordii Hook. f. (TwHF). Whether WFR has anti-RA effect, its molecular mechanism has not been elucidated.Aim of the studyOur study aims to clarify how WFR inhibits fibroblast-like synovial cells (FLS) activation and improves RA through Wnt11 action on the Wnt11/β-catenin signaling pathway.MethodsThe therapeutic effect of WFR on collagen-induced arthritis (CIA) rats was evaluated using methods such as rat arthritis score. The inhibitory effects and signaling pathways of WFR on the proliferation and inflammatory response of CIA FLS and RA FLS were studied using ELISA, CCK-8, RT-qPCR, Western blot, and immunofluorescence methods.ResultsWFR could effectively alleviate the arthritis symptoms of CIA rats; reduce the levels of IL-6, IL-1β, and TNF-α in the peripheral blood of CIA rats; and inhibit the expression of MMP3 and fibronectin. The data showed that WFR has a significant inhibitory effect on FLS proliferation. Furthermore, WFR inhibited the activation of Wnt/β-catenin signaling pathway and decreased the expression of Wnt11, β-catenin, CCND1, GSK-3β, and c-Myc, while the effects of WFR were reversed after overexpression of Wnt11.ConclusionsWFR improves RA by inhibiting the Wnt11/β-catenin signaling pathway, and Wnt11 is the direct target of WFR. This study provides a new molecular mechanism for WFR to improve RA and contributes to the clinical promotion of WFR.

Platelets: Physiology and Biochemistry

AbstractThis manuscript represents a republication of a manuscript originally published in STH in 2005. This republication is to help celebrate 50 years of publishing for STH. The original abstract follows.Platelets are specialized blood cells that play central roles in physiologic and pathologic processes of hemostasis, inflammation, tumor metastasis, wound healing, and host defense. Activation of platelets is crucial for platelet function that includes a complex interplay of adhesion and signaling molecules. This article gives an overview of the activation processes involved in primary and secondary hemostasis, for example, platelet adhesion, platelet secretion, platelet aggregation, microvesicle formation, and clot retraction/stabilization. In addition, activated platelets are predominantly involved in cross-talk to other blood and vascular cells. Stimulated “sticky” platelets enable recruitment of leukocytes at sites of vascular injury under high shear conditions. Platelet-derived microparticles as well as soluble adhesion molecules, sP-selectin and sCD40L, shed from the surface of activated platelets, are capable of activating, in turn, leukocytes and endothelial cells. This article focuses further on the new view of receptor-mediated thrombin generation of human platelets, necessary for the formation of a stable platelet–fibrin clot during secondary hemostasis. Finally, special emphasis is placed on important stimulatory and inhibitory signaling pathways that modulate platelet function.

A high-throughput two-cell assay for interrogating inhibitory signaling pathways in T cells

The recent success of immunotherapies relying on manipulation of T-cell activation highlights the value of characterising the mediators of immune checkpoint signaling. CRISPR/Cas9 is a popular approach for interrogating signaling pathways; however, the lack of appropriate assays for studying inhibitory signaling in T cells is limiting the use of large-scale perturbation-based approaches. Here, we adapted an existing Jurkat cell-based transcriptional reporter assay to study both activatory and inhibitory (PD-1-mediated) T-cell signaling using CRISPR-based genome screening in arrayed and pooled formats. We targeted 64 SH2 domain-containing proteins expressed by Jurkat T cells in an arrayed screen, in which individual targets could be assessed independently, showing that arrays can be used to study mediators of both activatory and inhibitory signaling. Pooled screens succeeded in simultaneously identifying many of the known mediators of proximal activating and inhibitory T-cell signaling, including SHP2 and PD-1, confirming the utility of the method. Altogether, the data suggested that SHP2 is the major PD-1-specific, SH2 family mediator of inhibitory signaling. These approaches should allow the systematic analysis of signaling pathways in T cells.

Plant-derived Durvalumab variants show efficient PD-1/PD-L1 blockade and therapeutically favourable FcR binding.

Immune checkpoint blocking therapy targeting the PD-1/PD-L1 inhibitory signalling pathway has produced encouraging results in the treatment of a variety of cancers. Durvalumab (Imfinzi® ) targeting PD-L1 is currently used for immunotherapy of several tumour malignancies. The Fc region of this IgG1 antibody has been engineered to reduce FcγR interactions with the aim of enhancing blockade of PD-1/PD-L1 interactions without the depletion of PD-L1-expressing immune cells. Here, we used Nicotiana benthamiana to produce four variants of Durvalumab (DL): wild-type IgG1 and its 'Fc-effector-silent' variant (LALAPG) carrying further modifications to increase antibody half-life (YTE); IgG4S228P and its variant (PVA) with Fc mutations to decrease binding to FcγRI. In addition, DL variants were produced with two distinct glycosylation profiles: afucosylated and decorated with α1,6-core fucose. Plant-derived DL variants were compared to the therapeutic antibody regarding their ability to (i) bind to PD-L1, (ii) block PD-1/PD-L1 inhibitory signalling and (iii) engage with the neonatal Fc receptor (FcRn) and various Fcγ receptors. It was found that plant-derived DL variants bind to recombinant PD-L1 and to PD-L1 expressed in gastrointestinal cancer cells and are able to effectively block its interaction with PD-1 on T cells, thereby enhancing their activation. Furthermore, we show a positive impact of Fc amino acid mutations and core fucosylation on DL's therapeutic potential. Compared to Imfinzi® , DL-IgG1 (LALAPG) and DL-IgG4 (PVA)S228P show lower affinity to CD32B inhibitory receptor which can be therapeutically favourable. Importantly, DL-IgG1 (LALAPG) also shows enhanced binding to FcRn, a key determinant of serum half-life of IgGs.

Single-cell transcriptomics reveals ferrimagnetic vortex iron oxide nanoring-mediated mild magnetic hyperthermia exerts antitumor effects by alleviating macrophage suppression in breast cancer

The potential of Ferrimagnetic vortex iron oxide nanoring-mediated mild magnetic hyperthermia (FVIO-MHT) in solid tumor therapy has been demonstrated. However, the impact of FVIO-MHT on the tumor microenvironment (TME) remains unclear. This study utilized single-cell transcriptome sequencing to examine the alterations in the TME in response to FVIO-MHT in breast cancer. The results revealed the cellular composition within the tumor microenvironment (TME) was primarily modified due to a decrease in tumor cells and an increased infiltration of myeloid cells. Subsequently, an enhancement in active oxygen (ROS) metabolism was observed, indicating oxidative damage to tumor cells. Interestingly, FVIO-MHT reprogrammed the macrophages’ phenotypes, as evidenced by alterations in the transcriptome characteristics associated with both classic and alternative activated phenotypes. And an elevated level of ROS generation and oxidative phosphorylation suggested that activated phagocytosis and inflammation occurred in macrophages. Additionally, cell–cell communication analysis revealed that FVIO-MHT attenuated the suppression between tumor cells and macrophages by inhibiting phagocytic checkpoint and macrophage migration inhibitory factor signaling pathways. Inhibition of B2m, an anti-phagocytosis checkpoint, could promote macrophage-mediated phagocytosis and significantly inhibit tumor growth. These data emphasize FVIO-MHT may promote the antitumor capabilities of macrophages by alleviating the suppression between tumor cells and macrophages.

CRISPR-Cas9-Based Gene Knockout of Immune Checkpoints in Expanded NK Cells.

Natural killer (NK) cell immunotherapy has emerged as a novel treatment modality for various cancer types, including leukemia. The modulation of inhibitory signaling pathways in T cells and NK cells has been the subject of extensive investigation in both preclinical and clinical settings in recent years. Nonetheless, further research is imperative to optimize antileukemic activities, especially regarding NK-cell-based immunotherapies. The central scientific question of this study pertains to the potential for boosting cytotoxicity in expanded and activated NK cells through the inhibition of inhibitory receptors. To address this question, we employed the CRISPR-Cas9 system to target three distinct inhibitory signaling pathways in NK cells. Specifically, we examined the roles of A2AR within the metabolic purinergic signaling pathway, CBLB as an intracellular regulator in NK cells, and the surface receptors NKG2A and CD96 in enhancing the antileukemic efficacy of NK cells. Following the successful expansion of NK cells, they were transfected with Cas9+sgRNA RNP to knockout A2AR, CBLB, NKG2A, and CD96. The analysis of indel frequencies for all four targets revealed good knockout efficiencies in expanded NK cells, resulting in diminished protein expression as confirmed by flow cytometry and Western blot analysis. Our in vitro killing assays demonstrated that NKG2A and CBLB knockout led to only a marginal improvement in the cytotoxicity of NK cells against AML and B-ALL cells. Furthermore, the antileukemic activity of CD96 knockout NK cells did not yield significant enhancements, and the blockade of A2AR did not result in significant improvement in killing efficiency. In conclusion, our findings suggest that CRISPR-Cas9-based knockout strategies for immune checkpoints might not be sufficient to efficiently boost the antileukemic functions of expanded (and activated) NK cells and, at the same time, point to the need for strong cellular activating signals, as this can be achieved, for example, via transgenic chimeric antigen receptor expression.

Molecular and structural basis of TIGIT: Nectin-4 interaction, a recently discovered pathway crucial for cancer immunotherapy

TIGIT (T cell immunoglobulin and ITIM domain) is an inhibitory receptor expressed on T and NK cells that interact with cell surface glycoprotein belonging to the nectin and nectin-like family of cell adhesion molecules, particularly nectin-2 and nectin-like 5 (PVR). Nectin-4 has been recently identified as a novel ligand for TIGIT and the interaction among them inhibits NK cell cytotoxicity. In this study, biophysical experiments were conducted to decipher the mechanism of this novel interaction, followed by structure-guided mutagenesis studies to map the nectin-4 binding interface on TIGIT. Using surface plasmon resonance, we deduced that TIGIT recognizes the membrane distal ectodomain of nectin-4 and the interaction is weaker than the well-characterized TIGIT: nectin-2 interaction. Deciphering the molecular basis of this newly identified interaction between TIGIT and nectin-4 will provide us important insight into the manipulation of this inhibitory signaling pathway, especially targeting cancer cells overexpressing nectin-4 that evade the immune surveillance of the body.

Restraint stress promotes monobenzone-induced depigmentation in mice via the activation of glucocorticoid receptor/macrophage migration inhibitory factor signaling pathway

Psychological stress triggers onset and development of vitiligo in humans. However, the mechanism of psychological stress on vitiligo remains unclear. The study aims to investigate whether psychological stress promotes vitiligo and explore the underlying mechanism. A depigmentation mouse model induced by applying a skin-bleaching reagent monobenzone to dorsal skin and an in vitro HaCaT keratinocyte death model induced by monobenzone were employed to explore the effect of restraint stress, which mimics psychological stress, on depigmentation. The results indicated that restraint stress promoted vitiligo-related depigmentation, vacuolisation, spongiosis, CD8+ T lymphocyte infiltration, and loss of melanocytes in the skin. Restraint stress activated cutaneous NLR family containing pyrin domain protein 3 (NLRP3) inflammasome. In addition, restraint stress aggravated anxiety-like behaviors and increased levels of macrophage migration inhibitory factor (MIF) and corticosterone in the circulation, accompanied with decreasing the expression of cutaneous 8-oxoguanine DNA glycosylase (OGG1) in depigmentation mice. In vitro experiments demonstrated that activation of glucocorticoid receptor (GR) by cortisol upregulated NLRP3 expression dependent on MIF, and directly decreased the transcription of OGG1. Blockade of MIF reversed the NLRP3 signal in restraint stress-induced depigmentation mice. In conclusion, restraint stress promotes vitiligo-related depigmentation in mice via the activation of GR/MIF signaling pathway. The findings provide a theoretical basis for prevention and treatments of vitiligo with therapies of targeting GR, MIF, and OGG1.

Tackling of Immunorefractory Tumors by Targeting Alternative Immune Checkpoints.

Physiologically, well known or traditional immune checkpoints (ICs), such as CTLA-4 and PD-1, are in place to promote tolerance to self-antigens and prevent generation of autoimmunity. In cancer, the ICs are effectively engaged by the tumor cells or stromal ells from the tumor microenvironment through expression of cognate ligands for the ICs present on the cell surface of CD8+ T lymphocytes. The ligation of ICs on CD8+ T lymphocytes triggers inhibitory signaling pathways, leading to quiescence or an exhaustion of CD8+ T lymphocytes. This results in failure of immunotherapy. To overcome this, several FDA-approved therapeutic antibodies are available, but the clinical outcome is quite variable due to the resistance encountered through upregulated expression of alternate ICs such as VISTA, LAG-3, TIGIT and TIM-3. This review focuses on the roles played by the traditional as well as alternate ICs and the contribution of associated signaling pathways in generating such resistance to immunotherapy. Combinatorial targeting of traditional and alternate ICs might be beneficial for immune-refractory tumors.

The HDAC inhibitor domatinostat induces type I interferon α in Merkel cell carcinoma by HES1 repression

BackgroundClass I selective histone deacetylase inhibitors (HDACi) have been previously demonstrated to not only increase major histocompatibility complex class I surface expression in Merkel cell carcinoma (MCC) cells by restoring the antigen processing and presentation machinery, but also exert anti-tumoral effect by inducing apoptosis. Both phenomena could be due to induction of type I interferons (IFN), as has been described for HDACi. However, the mechanism of IFN induction under HDACi is not fully understood because the expression of IFNs is regulated by both activating and inhibitory signaling pathways. Our own preliminary observations suggest that this may be caused by suppression of HES1.MethodsThe effect of the class I selective HDACi domatinostat and IFNα on cell viability and the apoptosis of MCPyV-positive (WaGa, MKL-1) and -negative (UM-MCC 34) MCC cell lines, as well as, primary fibroblasts were assessed by colorimetric methods or measuring mitochondrial membrane potential and intracellular caspase-3/7, respectively. Next, the impact of domatinostat on IFNA and HES1 mRNA expression was measured by RT-qPCR; intracellular IFNα production was detected by flow cytometry. To confirm that the expression of IFNα induced by HDACi was due to the suppression of HES1, it was silenced by RNA interference and then mRNA expression of IFNA and IFN-stimulated genes was assessed.ResultsOur studies show that the previously reported reduction in viability of MCC cell lines after inhibition of HDAC by domatinostat is accompanied by an increase in IFNα expression, both of mRNA and at the protein level. We confirmed that treatment of MCC cells with external IFNα inhibited their proliferation and induced apoptosis. Re-analysis of existing single-cell RNA sequencing data indicated that induction of IFNα by domatinostat occurs through repression of HES1, a transcriptional inhibitor of IFNA; this was confirmed by RT-qPCR. Finally, siRNA-mediated silencing of HES1 in the MCC cell line WaGa not only increased mRNA expression of IFNA and IFN-stimulated genes but also decreased cell viability.ConclusionOur results demonstrate that the direct anti-tumor effect of HDACi domatinostat on MCC cells is at least in part mediated via decreased HES1 expression allowing the induction of IFNα, which in turn causes apoptosis.

Abstract 6372: In situ detection of various activated immune checkpoints via next-generation proximity ligation assays in tumor tissue

Abstract Immune checkpoints (ICs), which are inhibitory signaling pathways that can down-modulate the immune responses of T cells, are pivotal in peripheral tissues and for maintaining immune self-tolerance. Among the many molecularly defined IC proteins, some of the most studied ones are CTLA-4 and its binding partners important for early T-cell co-inhibition, along with the PD-1/PD-L1 axis proteins that carry out late co-inhibitory signals. Notably, in addition to antigen presenting and other immune cells, many tumors also express CTLA-4 and PD-L1, which facilitate tumor evasion from the immune system. The inhibition of these IC proteins has revolutionized the field of cancer therapy, but its efficiency has been limited to a poorly defined subset of patients. Patient outcomes are likely to have a stronger correlation to high levels of PD-1/PD-L1 interaction and other hallmarks of pathway activation, such as PD-1 phosphorylation and recruitment of SHP-2, than to the overexpression of a single IC protein alone. To improve the predictive value of tissue staining, we created an immuno-oncology line of ultrasensitive kits based on proximity ligation, which detect the activation of multiple ICs. Naveni™ PD1/PD-L1 is a tool for direct visualization of the interaction between PD-1 and PD-L1, and has been verified in various FFPE tumor tissues. Naveni™ pY PD1 sensitively detects PD1 phosphorylation, which is the first step in the PD-1/PD-L1 inhibitory pathway activation. To study the subsequent recruitment of SHP-2 to the activated PD-1 receptor, which is crucial in immune cells but dispensable when the pathway is activated between two tumor cells, one can use the upcoming Naveni™ PD1/SHP-2 kit. Furthermore, we are developing assays to observe the competing interactions of CTLA-4 and CD28 with their binding partners CD80 and CD86, the interplay of which is pivotal for the initiation of early co-inhibition. All kits can be used on consecutive tissue sections to obtain a comprehensive picture of tumor IC pathway activation, which may not always correspond to CTLA-4, PD-1 or PD-L1 overexpression. While these kits have a chromogenic readout applicable to brightfield microscopy, we also have preliminary data on a PD-1/PD-L1 assay with a fluorescent readout thanks to which it can also be multiplexed. The multiplex feature generates an immune profile which may help improve immunotherapeutic strategies. The Naveni™ assays can be applied in basic research to elucidate the interplay of IC axes and downstream molecules, in pre-clinical and clinical research to compare stainings with the existing IHC assays and evaluate the potential prognostic value of interaction detection, and in pharma, aiding the development of new drugs or bispecific antibodies. Citation Format: Desirée Edén, Ka I Au Ieong, Naomi Cook, Doroteya Raykova, Agata Zieba Wicher. In situ detection of various activated immune checkpoints via next-generation proximity ligation assays in tumor tissue. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6372.

Anti-Inflammatory and Anti-Thrombogenic Properties of Arterial Elastic Laminae

Elastic laminae, an elastin-based, layered extracellular matrix structure in the media of arteries, can inhibit leukocyte adhesion and vascular smooth muscle cell proliferation and migration, exhibiting anti-inflammatory and anti-thrombogenic properties. These properties prevent inflammatory and thrombogenic activities in the arterial media, constituting a mechanism for the maintenance of the structural integrity of the arterial wall in vascular disorders. The biological basis for these properties is the elastin-induced activation of inhibitory signaling pathways, involving the inhibitory cell receptor signal regulatory protein α (SIRPα) and Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1). The activation of these molecules causes deactivation of cell adhesion- and proliferation-regulatory signaling mechanisms. Given such anti-inflammatory and anti-thrombogenic properties, elastic laminae and elastin-based materials have potential for use in vascular reconstruction.

ULK1 Blockade Preferentially Targets Germinal Centre B-Cell - Diffuse Large B-Cell Lymphoma Subtype By Attenuating Autophagy, c-MYC and Inflammation

Diffuse Large B-cell Lymphoma (DLBCL) is a heterogeneous lymphoid malignancy. Gene Expression profiling (GEP) has characterized two distinct subsets: Germinal Centre B-cell (GCB) and Activated B-cell (ABC) DLBCL. Oncogenic PI3K-AKT signaling has been identified in primary DLBCL subtypes[1]. PI3K-AKT is activated in response to the loss of PTEN in GCB-DLBCL. In ABC-DLBCL the activation is associated with CD79B mutations and concomitant MYD88 alterations. The Bruton Tyrosine Kinase (BTK) functions as an intermediary kinase. Ibrutinib (BTK inhibitor) has demonstrated promising capability in ABC-DLBCL unlike GCB tumors, warranting further investigations[2]. PI3K-AKT-mTOR signaling is also a known regulator of macro-autophagy (herein referred to as autophagy). ULK1 complex is critical for the initiation of autophagy. Aberrant signaling in this pathway promotes nutritional adaptation to malignant cells and contributes to drug resistance. We hypothesize autophagy facilitates cytoprotection and contributes to drug resistance including R-CHOP and Ibrutinib in GCB-DLBCL. Dual targeting of the BTK with Ibrutinib and autophagy initiating complex(es) would be a strategic method to impair these oncogenic functions. To determine the presence of increased autophagy related genes (ATGs) and its association to R-CHOP treatment outcome, we analyzed the GEP of patients from the REMODL-B trial (R-CHOP: GCB n=240 and ABC n=121)[3]. Gene set enrichment analysis (GSEA) showed no difference between the DLBCL patients indicating mutual autophagy dependency. Genes associated to worst overall survival (OS) in autophagy initiating complex I/ ULK1 complex (ULK1, RB1CC1/FIP200 and ATG13) and complex II (AMBRA1, PIK3C3/VPS34, PIK3R4/VPS15 and USO1/p115) were identified using Kaplan-Meier curves and overlapped according to their respective complexes. Statistical analysis confirmed ULK1 complex was significantly dominate in response to R-CHOP treatment leading to poor OS (p=0.0403). These findings provide a rational to inhibit autophagy via the ULK1 complex in GCB patients. Alike, multiple GCB (n=7) and ABC (n=5) cell lines showed substantial autophagy dependency using LC3B autophagy marker expression. Ibrutinib treatment enhanced autophagic flux in GCB cell lines. Addition of ULK1 complex inhibitor (MRT68921) augmented the anti-tumor activity of Ibrutinib in HT, Oci-Ly1, Oci-Ly18 and SUDHL-6 GCB cell lines and activated caspase dependent apoptosis. Interestingly, ULK1 complex inhibitors (MRT68921/ ULK1-101) induced acute NF-ҡB activation in multiple GCB and ABC lymphoma lines irrespective of their NF-ҡB mutational status. RNA sequencing of GCB and ABC cell lines treated with MRT68921, or vehicle reported diverse ULK1 inhibitory signaling pathways. Oci-Ly1 (GCB, c-MYC amplification) treated cells significantly downregulated genes associated to PI3K-mTOR activity/ signaling, autophagy, metabolism, and IL-6. GSEA reported a substantial decrease in c-MYC transcriptional activation/ pathway and TNF signaling. Immunoblotting data confirmed ULK1 inhibition dephosphorylated c-myc(ser62) in a time dependent manner in Oci-Ly1 and Oci-Ly18. In contrast, Oci-Ly3 (ABC, c-MYC amplification) treated cells upregulated genes involved in JAK-STAT pathway, IL-6, and apoptosis. C-MYC remained unaffected. In summary, GCB-DLBCL patients treated with R-CHOP harbor increased autophagy signatures that potentially dictate treatment outcome. Our in vitro data demonstrates ULK1 inhibition sensitizes GCB cell lines to Ibrutinib due to diverse role in regulating NF-ҡB, c-MYC and inflammation. Unlike, ABC, where ULK1 blockade promotes immunogenic-dependent cell death.

HEMORRHAGIC PLEURAL EFFUSION IN A PATIENT WITH CHRONIC LYMPHOCYTIC LEUKEMIA ON IBRUTINIB THERAPY

SESSION TITLE: Problems in the Pleura Case Posters 1SESSION TYPE: Case Report PostersPRESENTED ON: 10/17/2022 12:15 pm - 01:15 pmINTRODUCTION: Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase (Btk), approved for treatment of a variety of B-cell malignancies, including chronic lymphocytic leukemia (CLL). There is an association of increased risk of bleeding with ibrutinib due to platelet dysfunction caused by the medication. Bleeding is usually non-life threating such as subcutaneous or mucosal bleeding, epistaxis, and ecchymosis. But major bleeding has been reported such as intracranial hemorrhage and gastrointestinal hemorrhage. Thoracic complications from ibrutinib are rare. Below is a case report discussing a hemorrhagic pleural effusion thought to be caused by Ibrutinib.CASE PRESENTATION: Patient is a 78-year-old male initially diagnosed with CLL on flow cytometry showing a low-grade B cell lymphoproliferative process. Patient was monitored by Hematology and when kappa light chain numbers began to rise, a bone marrow biopsy was performed showing 90% infiltration of the marrow with lymphoid cells. Patient was started on Ibrutinib therapy and responded well to treatment. A year after starting therapy, patient presented to the emergency room with increased shortness of breath and fatigue. Patient was found to be COVID-19 positive and chest x-ray showed a large right sided pleural effusion. Thoracentesis was performed draining 1650cc of bloody fluid. Fluid studies revealed a lymphocytic effusion with RBC count 1,185375, WBC of 1751. Cultures and cytology were negative. On further history, patient was without recent trauma or surgery, CTA chest was negative for pulmonary embolism. QuantiFERON Gold test was negative, indicating low likelihood of tuberculosis. Patient was not on any antiplatelet or systemic anticoagulation medications. Ibrutinib therapy was held during hospitalization and pleural effusion did not reaccumulate. Patient passed away during hospital stay secondary to respiratory failure due to COVID-19.DISCUSSION: Ibrutinib is an orally bioavailable bruton tyrosine kinase inhibitor (BTKi) and forms an irreversible covalent bound to BTK at the Cysteine-481 residue. Ibrutinib predisposes to bleeding by inhibiting BTK and Tec, which play a role in the inhibitory signaling pathway of platelet collagen receptors such as glycoprotein VI (GP VI) and C-type lectin-like receptor 2 (CLEC-2). Our patient had no other risk factors for developing a hemorrhagic effusion. CLL itself can cause malignant effusions, one study found the incidence of malignant effusions among patients with CLL to be 9%, but the effusion was noted to be serous or serosanguinous and there was pleural involvement in all patients which was not the case in our patient.CONCLUSIONS: There is currently a minimal amount of data to guide clinicians regarding the use of ibrutinib in patients at high risk of bleeding or on anticoagulant or antiplatelet therapy. It is important to realize bleeding complications related to ibrutinib therapy can occur.Reference #1: Shatzel JJ, Olson SR, Tao DL, McCarty OJT, Danilov AV, DeLoughery TG. Ibrutinib-associated bleeding: pathogenesis, management and risk reduction strategies. J Thromb Haemost. 2017;15(5):835-847. doi:10.1111/jth.13651Reference #2: Burger JA, Tedeschi A, Barr PM, et al. Ibrutinib as Initial Therapy for Patients with Chronic Lymphocytic Leukemia. N Engl J Med. 2015;373(25):2425-2437. doi:10.1056/NEJMoa1509388Reference #3: Paydas S. Management of adverse effects/toxicity of ibrutinib. Crit Rev Oncol Hematol. 2019;136:56-63. doi:10.1016/j.critrevonc.2019.02.001DISCLOSURES: No relevant relationships by fatima aliNo relevant relationships by Joan Wiley SESSION TITLE: Problems in the Pleura Case Posters 1 SESSION TYPE: Case Report Posters PRESENTED ON: 10/17/2022 12:15 pm - 01:15 pm INTRODUCTION: Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase (Btk), approved for treatment of a variety of B-cell malignancies, including chronic lymphocytic leukemia (CLL). There is an association of increased risk of bleeding with ibrutinib due to platelet dysfunction caused by the medication. Bleeding is usually non-life threating such as subcutaneous or mucosal bleeding, epistaxis, and ecchymosis. But major bleeding has been reported such as intracranial hemorrhage and gastrointestinal hemorrhage. Thoracic complications from ibrutinib are rare. Below is a case report discussing a hemorrhagic pleural effusion thought to be caused by Ibrutinib. CASE PRESENTATION: Patient is a 78-year-old male initially diagnosed with CLL on flow cytometry showing a low-grade B cell lymphoproliferative process. Patient was monitored by Hematology and when kappa light chain numbers began to rise, a bone marrow biopsy was performed showing 90% infiltration of the marrow with lymphoid cells. Patient was started on Ibrutinib therapy and responded well to treatment. A year after starting therapy, patient presented to the emergency room with increased shortness of breath and fatigue. Patient was found to be COVID-19 positive and chest x-ray showed a large right sided pleural effusion. Thoracentesis was performed draining 1650cc of bloody fluid. Fluid studies revealed a lymphocytic effusion with RBC count 1,185375, WBC of 1751. Cultures and cytology were negative. On further history, patient was without recent trauma or surgery, CTA chest was negative for pulmonary embolism. QuantiFERON Gold test was negative, indicating low likelihood of tuberculosis. Patient was not on any antiplatelet or systemic anticoagulation medications. Ibrutinib therapy was held during hospitalization and pleural effusion did not reaccumulate. Patient passed away during hospital stay secondary to respiratory failure due to COVID-19. DISCUSSION: Ibrutinib is an orally bioavailable bruton tyrosine kinase inhibitor (BTKi) and forms an irreversible covalent bound to BTK at the Cysteine-481 residue. Ibrutinib predisposes to bleeding by inhibiting BTK and Tec, which play a role in the inhibitory signaling pathway of platelet collagen receptors such as glycoprotein VI (GP VI) and C-type lectin-like receptor 2 (CLEC-2). Our patient had no other risk factors for developing a hemorrhagic effusion. CLL itself can cause malignant effusions, one study found the incidence of malignant effusions among patients with CLL to be 9%, but the effusion was noted to be serous or serosanguinous and there was pleural involvement in all patients which was not the case in our patient. CONCLUSIONS: There is currently a minimal amount of data to guide clinicians regarding the use of ibrutinib in patients at high risk of bleeding or on anticoagulant or antiplatelet therapy. It is important to realize bleeding complications related to ibrutinib therapy can occur. Reference #1: Shatzel JJ, Olson SR, Tao DL, McCarty OJT, Danilov AV, DeLoughery TG. Ibrutinib-associated bleeding: pathogenesis, management and risk reduction strategies. J Thromb Haemost. 2017;15(5):835-847. doi:10.1111/jth.13651 Reference #2: Burger JA, Tedeschi A, Barr PM, et al. Ibrutinib as Initial Therapy for Patients with Chronic Lymphocytic Leukemia. N Engl J Med. 2015;373(25):2425-2437. doi:10.1056/NEJMoa1509388 Reference #3: Paydas S. Management of adverse effects/toxicity of ibrutinib. Crit Rev Oncol Hematol. 2019;136:56-63. doi:10.1016/j.critrevonc.2019.02.001 DISCLOSURES: No relevant relationships by fatima ali No relevant relationships by Joan Wiley

Abstract 3608: Triple checkpoint blockade, but not anti-PD1 alone, enhances the efficacy of engineered adoptive T cell therapy in advanced ovarian cancer

Abstract Background: Less than half of ovarian cancer patients survive five years after diagnosis. This rate has changed little in the last 30 years, highlighting the need for novel therapies. A promising new strategy with the potential to control tumor growth without toxicity to healthy tissues employs immune T cells engineered to target proteins uniquely overexpressed in tumors. Mesothelin (Msln) is overexpressed in high grade serous ovarian cancer, contributes to the malignant and invasive phenotype, and has limited expression in healthy cells, making it a candidate immunotherapy target in these tumors. Methods: The ID8VEGF mouse cell line was used to evaluate if T cells engineered to express a mouse Msln-specific high-affinity T cell receptor (TCRMsln) can kill murine ovarian tumor cells in vitro and in vivo. Tumor-bearing mice were treated with TCRMsln T cells plus anti-PD-1, anti-Tim-3 or anti-Lag-3 checkpoint-blocking antibodies administered alone or in combination, ultimately allowing targeting up to three inhibitory receptors simultaneously. Single cell RNA sequencing was used to profile the impact of combination checkpoint blockade on both the engineered T cells and the tumor microenvironment. Results: In a disseminated ID8 tumor model, adoptively transferred TCRMsln T cells preferentially accumulated within established tumors, delayed ovarian tumor growth, and significantly prolonged mouse survival. However, our data also revealed that elements in the tumor microenvironment (TME) limited engineered T cell persistence and ability to kill cancer cells. Triple checkpoint blockade, but not single- or double-agent treatment, dramatically increased effector cytokine production by intratumoral TCRMsln T cells. Single cell RNA-sequencing revealed gene expression changes in engineered T cells and myeloid cells in the TME consistent with activation and inflammation. Moreover, combining adoptive immunotherapy with triple checkpoint blockade prolonged survival in the cohort of treated tumor-bearing mice, relative to TCRMsln with or without anti-PD1, or double-agent treatments. Conclusions: Inhibitory receptor/ligand interactions within the tumor microenvironment can dramatically reduce T cell function, suggesting tumor cells may increase expression of the ligands for PD-1, Tim-3 and Lag-3 for protection from tumor-infiltrating lymphocytes. In a model of advanced ovarian cancer, triple checkpoint blockade significantly improved the anti-tumor function of transferred engineered T cells and improved outcomes in mice in a setting in which single checkpoint blockade had no significant activity. These results suggest that disrupting multiple inhibitory signaling pathways simultaneously, which can be more safely pursued in a cell intrinsic form through genetic engineering, may be necessary for improved efficacy in patients. Citation Format: Kristin G. Anderson, Yapeng Su, Madison G. Burnett, Breanna M. Bates, Magdalia L. Rodgers Suarez, Susan L. Ruskin, Aesha Vakil, Valentin Voillet, Raphael Gottardo, Philip Greenberg. Triple checkpoint blockade, but not anti-PD1 alone, enhances the efficacy of engineered adoptive T cell therapy in advanced ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3608.

Correction to: Matrine Treatment Blocks NogoA-Induced Neural Inhibitory Signaling Pathway in Ongoing Experimental Autoimmune Encephalomyelitis

Correction to: Matrine Treatment Blocks NogoA-Induced Neural Inhibitory Signaling Pathway in Ongoing Experimental Autoimmune Encephalomyelitis

Engineering iPSC-derived neutrophils to fight infection

Abstract Neutrophils are the initial responders to infection and injury and are critical for host survival. Immunocompromised patients are prone to recurrent bacterial and fungal infections which may require granulocyte transfusion. However, these transfusions have minimal efficacy as donor material is limited and highly heterogeneous. Induced pluripotent stem cells (iPSCs) are a promising option for generating a defined therapeutic that can improve patient outcomes. Therefore, we aimed to engineer iPSC-derived neutrophils to improve recruitment and antimicrobial function. Prior research in the field has shown that iPSC-derived neutrophils have limited function compared to primary human neutrophils, likely due to inhibitory signaling pathways. To generate iPSC-derived neutrophils with enhanced capacity, we utilized CRISPR/Cas9 to delete the protein tyrosine phosphatase 1B (PTP1B), a negative regulator of neutrophil function. PTP1B−/− neutrophils displayed increased cellular migration and inflammatory cytokine signaling in response to bacterial stimuli versus WT cells. Additionally, upon selection of cells with mature neutrophil markers, these PTP1B−/− neutrophils show similar fungal killing ability and improved phagocytosis compared to WT. Thus, these data indicate that deletion of PTP1B can improve the antimicrobial function of iPSC neutrophils and highlights the value of our system for genetically engineering iPSC-derived neutrophils. Supported by grants from the NIH (5R01AI134749-03 and Microbes in Health and Disease T32 NIAID: T32AI055397)