Presence Of IL-2 Research Articles

Fatty acid metabolism constrains Th9 cell differentiation and antitumor immunity via the modulation of retinoic acid receptor signaling

T helper 9 (Th9) cells are interleukin 9 (IL-9)-producing cells that have diverse functions ranging from antitumor immune responses to allergic inflammation. Th9 cells differentiate from naïve CD4+ T cells in the presence of IL-4 and transforming growth factor-beta (TGF-β); however, our understanding of the molecular basis of their differentiation remains incomplete. Previously, we reported that the differentiation of another subset of TGF-β–driven T helper cells, Th17 cells, is highly dependent on de novo lipid biosynthesis. On the basis of these findings, we hypothesized that lipid metabolism may also be important for Th9 cell differentiation. We therefore investigated the differentiation and function of mouse and human Th9 cells in vitro under conditions of pharmacologically or genetically induced deficiency of the intracellular fatty acid content and in vivo in mice genetically deficient in acetyl-CoA carboxylase 1 (ACC1), an important enzyme for fatty acid biosynthesis. Both the inhibition of de novo fatty acid biosynthesis and the deprivation of environmental lipids augmented differentiation and IL-9 production in mouse and human Th9 cells. Mechanistic studies revealed that the increase in Th9 cell differentiation was mediated by the retinoic acid receptor and the TGF-β–SMAD signaling pathways. Upon adoptive transfer, ACC1-inhibited Th9 cells suppressed tumor growth in murine models of melanoma and adenocarcinoma. Together, our findings highlight a novel role of fatty acid metabolism in controlling the differentiation and in vivo functions of Th9 cells.

AtRA Attenuates High Salt-Driven EAE Mainly Through Suppressing Th17-Like Regulatory T Cell Response Mediated by the Inhibition of IL-23R Signaling Pathway.

High salt diet (HSD) is implicated in numerous disorders, which boosts Th17 cell development and weakens immunosuppressive function of regulatory T cells (Treg cells) Treg cells, leading to the exacerbation of EAE. However, little is known regarding the harness of excessive proinflammatory responses evoked by HSD. Here we show that atRA, a key vitamin A metabolite with multifaceted immunoregulatory properties has the potential in inhibiting the proinflammatory reaction of high salt. Treatment with atRA in vivo elicited the Treg generation in cervical and axillary lymph nodes (CALs), and in CNS of experimental autoimmune encephalomyelitis (EAE). Meanwhile, the proportion of Th17-like Treg cells (RORγt-positive or GM-CSF-positive Treg cells) decreased in CALs. atRA also inhibited IL-17A expression in CD4+ effector T cells. In-vitro mechanistic studies showed that atRA inhibit IL-23R but not SGK1 expression in Treg cells and this results in maintained immunosuppressive function of Treg cells even in the presence of IL-6 and high salt. Furthermore, treatment of EAE with anti-IL-23R mAb attenuated HSD-provoked EAE progress. This was associated with a reduction in the number of CNS-infiltrating Th17 cells and an increase of CAL-Treg cells. Mechanically, treatment with atRA significantly promoted LP-CD103+CD11c+ dendritic cells, a subgroup of cells most closely involved in endogenous retinoic acid metabolism, and enhanced intestinal Aldh1a1 and Rdh10 expression from HSD-fed EAE mice. Interestingly, anti-IL-23R mAb administration also reduced IL-23R expression in Treg cells, along with the increased proportion of LP-CD103+CD11c+ dendritic cells and Rdh10 mRNA expression. In conclusion, administration of atRA might be a way to combat the proinflammatory effects of HSD. Meanwhile, systematic inhibition of IL-23R also had a moderate therapeutic potential in inhibiting inflammatory effects of high salt, which may serve as a basis for the identification of novel therapeutic strategies against HSD-driven autoimmune disorders.

Anakinra-Loaded Sphingomyelin Nanosystems Modulate In Vitro IL-1-Dependent Pro-Tumor Inflammation in Pancreatic Cancer.

Pancreatic cancer is a very aggressive disease with a dismal prognosis. The tumor microenvironment exerts immunosuppressive activities through the secretion of several cytokines, including interleukin (IL)-1. The IL-1/IL-1 receptor (IL-1R) axis is a key regulator in tumor-promoting T helper (Th)2- and Th17-type inflammation. Th2 cells are differentiated by dendritic cells endowed with Th2-polarizing capability by the thymic stromal lymphopoietin (TSLP) that is secreted by IL-1-activated cancer-associated fibroblasts (CAFs). Th17 cells are differentiated in the presence of IL-1 and other IL-1-regulated cytokines. In pancreatic cancer, the use of a recombinant IL-1R antagonist (IL1RA, anakinra, ANK) in in vitro and in vivo models has shown efficacy in targeting the IL-1/IL-1R pathway. In this study, we have developed sphingomyelin nanosystems (SNs) loaded with ANK (ANK-SNs) to compare their ability to inhibit Th2- and Th17-type inflammation with that of the free drug in vitro. We found that ANK-SNs inhibited TSLP and other pro-tumor cytokines released by CAFs at levels similar to ANK. Importantly, inhibition of IL-17 secretion by Th17 cells, but not of interferon-γ, was significantly higher, and at lower concentrations, with ANK-SNs compared to ANK. Collectively, the use of ANK-SNs might be beneficial in reducing the effective dose of the drug and its toxic effects.

The safety and efficacy of adipose tissue-derived exosomes in treating mild to moderate plaque psoriasis: A clinical study

AimThis study evaluates the safety and efficacy of autologous adipose-derived mesenchymal stem cell-derived exosomes as a treatment for Psoriasis, a chronic immune-related skin and joint disorder, compared to current treatments like topicals, phototherapy, and systemic. Materials and methodsThe study isolated exosomes from Mesenchymal Stem Cells(MSCs) of healthy adipose tissue using ultracentrifugation. 12 patients with plaque psoriasis were divided into three groups and given single doses of exosomes. Tissue samples were collected pre- and post-treatment and examined for inflammatory(TNFα, IL23, IL17, IFNγ, CD3) and anti-inflammatory (FOXP3, IL10) markers. The severity of the lesion was also evaluated. Key findingsIn this study, it was found that erythema and induration (P < 0.05) decreased significantly in patients receiving 200 μg. Still, this reduction in scaling was not significant, the thickness was significantly reduced in patients receiving 100 and 200 μg doses (P < 0.05). H&E evaluation showed that the decreasing trend in these patients was not significant (P > 0.05). IHC evaluation in patients receiving doses of 100 and 200 μg showed a decrease in the presence of IL17 (P < 0.05, <0.001) & CD3(P < 0.001, <0.05) and a considerable increase in FOXP3(P ≤ 0.001), in the tissue samples of the patients. Examining the expression of inflammatory factors also shows that dose 200 μg decreased the expression of IL17(P > 0.05), IFNγ(P > 0.05), IL23(P < 0.05), & TNFα(P ≤ 0.05) and increased the expression of the anti-inflammatory factor IL10(P < 0.05). SignificanceThe study indicates that a 200 μg dose is optimal for patients, but a larger patient population is needed for more reliable results. Additionally, higher doses or multiple injections with specific intervals can increase confidence.

Prevalence of type 2 inflammation in patients with chronic rhinosinusitis with nasal polyps in Saudi Arabia.

Chronic Rhinosinusitis (CRS) is a common condition causing a significant worldwide burden, affecting 5%-12% of the general population. CRS is classified into type 2 and non-type 2 disease based on endotype dominance. Type 2 inflammation is distinguished by the presence of IL-4, IL-5, and IL-13 cytokines, along with eosinophil and mast cell activation and recruitment. Evidence of type 2 inflammation is ascertained by tissue eosinophil count >10/high-power field (HPF) or serum eosinophil >250 cells/mcL or total immunoglobulin E (IgE) > 100 IU/ml. To investigate the prevalence and characteristics of type 2 inflammation in patients who presented with nasal polyps and underwent Endoscopic Sinus Surgery (ESS) in Saudi Arabia. A retrospective cross-sectional Study. This study was conducted among patients who presented with nasal polyps and underwent ESS at King Saud University Medical City (KSUMC) from 2015 to 2020. Patients with nasal/sinus diseases other than Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) were excluded. Demographic data, olfaction status, and co-morbidities were collected, and radiological images were evaluated. Type 2-CRS was determined by meeting at least one of three predictor criteria (blood eosinophils ≥250 cells/mcL, tissue eosinophils ≥10/HPF, or total IgE levels ≥100 IU/ml). Blood parameters and histopathologic analysis were obtained for each patient. Of the 381 patients included in the study, the prevalence of type 2-CRS, based on the EPOS2020 criteria, was 99.7% in our population. Among these patients, 47.5% had hyposmia, 38.8% had anosmia, and 13.6% had normal olfaction. The most prevalent co-morbidity was allergic rhinitis, followed by bronchial asthma. This study aimed to determine the prevalence of type 2 inflammation among patients Diagnosed with CRSwNP and underwent ESS in Saudi Arabia. The results showed a prevalence of 99.7%, indicating that almost all recorded patients with CRSwNP in our population had type 2 inflammation.

Multiomics analysis identified IL-4–induced IL1RL1high eosinophils characterized by prominent cysteinyl leukotriene metabolism

BackgroundClinical studies demonstrated that IL-4, a type 2 cytokine, plays an important role in the pathogenesis of chronic rhinosinusitis (CRS) and eosinophilic asthma (EA). However, the direct effect of IL-4 on eosinophils remains unclear. ObjectiveWe aim to elucidate the inflammatory effects of IL-4 on the functions of human eosinophils. MethodsMulti-omics analysis comprising transcriptomics, proteomics, lipidomics, quantitative RT-PCR, and flow cytometry was performed using blood eosinophils from healthy subjects stimulated with IL-4, IL-5, or their combination. ResultsTranscriptomic and proteomic analyses revealed that both IL-4 and IL-5 upregulate the expression of gamma-gultamyl transferase 5 (GGT5), a fatty acid-metabolizing enzyme that converts leukotriene C4 (LTC4) into LTD4. In addition, IL-4 specifically upregulates the expression of IL1RL1, a receptor for IL-33 and transglutaminase 2 (TGM2). Additional transcriptomic analysis of cells stimulated with IL-13 revealed altered gene expression profiles, characterized by the upregulation of GGT5, TGM2, and IL1RL1. IL-13-induced changes were not totally different from IL-4-induced one. Lipidomic analysis revealed that IL-5 and IL-4 additively increased the extracellular release of LTD4. In vitro experiments revealed that STAT6 and IL-4 receptor α control the expression of these molecules in the presence of IL-4 and IL-13. Analysis of eosinophils derived from patients with allergic disorders indicated the involvement of IL-4 and IL-13 at the inflamed sites. ConclusionsIL-4 induces the pro-allergic phenotype of IL1RL1high eosinophils with prominent cysteinyl leukotriene metabolism via STAT6. These cellular changes represent potential therapeutic targets for CRS and EA.

Myelin Oligodendrocyte Glycoprotein (MOG)35-55 Mannan Conjugate Induces Human T-Cell Tolerance and Can Be Used as a Personalized Therapy for Multiple Sclerosis.

We have previously performed preclinical studies with the oxidized mannan-conjugated peptide MOG35-55 (OM-MOG35-55) in vivo (EAE mouse model) and in vitro (human peripheral blood) and demonstrated that OM-MOG35-55 suppresses antigen-specific T cell responses associated with autoimmune demyelination. Based on these results, we developed different types of dendritic cells (DCs) from the peripheral blood monocytes of patients with multiple sclerosis (MS) or healthy controls presenting OM-MOG35-55 or MOG-35-55 to autologous T cells to investigate the tolerogenic potential of OM-MOG35-55 for its possible use in MS therapy. To this end, monocytes were differentiated into different DC types in the presence of IL-4+GM-CSF ± dexamethasone (DEXA) ± vitamin D3 (VITD3). At the end of their differentiation, the DCs were loaded with peptides and co-cultured with T cells +IL-2 for 4 antigen presentation cycles. The phenotypes of the DC and T cell populations were analyzed using flow cytometry and the secreted cytokines using flow cytometry or ELISA. On day 8, the monocytes had converted into DCs expressing the typical markers of mature or immature phenotypes. Co-culture of T cells with all DC types for 4 antigen presentation cycles resulted in an increase in memory CD4+ T cells compared to memory CD8+ T cells and a suppressive shift in secreted cytokines, mainly due to increased TGF-β1 levels. The best tolerogenic effect was obtained when patient CD4+ T cells were co-cultured with VITD3-DCs presenting OM-MOG35-55, resulting in the highest levels of CD4+PD-1+ T cells and CD4+CD25+Foxp3+ Τ cells. In conclusion, the tolerance induction protocols presented in this work demonstrate that OM-MOG35-55 could form the basis for the development of personalized therapeutic vaccines or immunomodulatory treatments for MS.

Involvement of Janus kinase-dependent Bcl-xL overexpression in steroid resistance of group 2 innate lymphoid cells in asthma.

The mechanisms underlying the development of steroid resistance in asthma remain unclear. To establish whether as well as the mechanisms by which the activation of Janus kinases (JAKs) is involved in the development of steroid resistance in asthma, murine steroid-resistant models of the proliferation of group 2 innate lymphoid cells (ILC2s) in vitro and asthmatic airway inflammation in vivo were analysed. ILC2s in the lungs of BALB/c mice were sorted and then incubated with IL-33, thymic stromal lymphopoietin (TSLP), and/or IL-7 with or without dexamethasone (10 nM), the pan-JAK inhibitor, delgocitinib (1-10 000 nM), and/or the Bcl-xL inhibitor, navitoclax (1-100 nM), followed by the detection of viable and apoptotic cells. The anti-apoptotic factor, Bcl-xL was detected in ILC2s by flow cytometry. As a steroid-resistant asthma model, ovalbumin (OVA)-sensitized BALB/c mice were intratracheally challenged with OVA at a high dose of 500 μg four times. Dexamethasone (1 mg/kg, i.p.), delgocitinib (3-30 mg/kg, p.o.), or navitoclax (30 mg/kg, p.o.) was administered during the challenges. Cellular infiltration into the lungs was analysed by flow cytometry. Airway remodelling was histologically evaluated. The following results were obtained. (1) Cell proliferation concomitant with a decrease in apoptotic cells was induced when ILC2s were cultured with TSLP and/or IL-7, and was potently inhibited by dexamethasone. In contrast, when the culture with TSLP and IL-7 was performed in the presence of IL-33, the proliferative response exhibited steroid resistance. Steroid-resistant ILC2 proliferation was suppressed by delgocitinib in a concentration-dependent manner. (2) The culture with IL-33, TSLP, and IL-7 induced the overexpression of Bcl-xL, which was clearly inhibited by delgocitinib, but not by dexamethasone. When ILC2s were treated with navitoclax, insensitivity to dexamethasone was significantly cancelled. (3) The development of airway remodelling and the infiltration of ILC2s into the lungs in the asthma model were not suppressed by dexamethasone, but were dose-dependently inhibited by delgocitinib. Combination treatment with dexamethasone and either delgocitinib or navitoclax synergistically suppressed these responses. Therefore, JAKs appear to play significant roles in the induction of steroid resistance by up-regulating Bcl-xL in ILC2s. The inhibition of JAKs and Bcl-xL has potential as pharmacotherapy for steroid-resistant asthma, particularly that mediated by ILC2s.

Conditionally immortalized cell lines with mast cell potential

Abstract Prior to the establishment of definitive hematopoiesis, mast cells (MCs) derived from the yolk sac and fetal liver colonize diverse tissues, maintaining a presence throughout life. Following the establishment of definitive hematopoiesis, hematopoietic stem cells from the bone marrow (BM) also contribute to the MC pool. The diverse origins and tissue-resident nature of MCs complicate their study. Therefore, a system facilitating the expansion of MC progenitors and their controlled differentiation becomes crucial. This report outlines the development of conditionally immortalized MC progenitor cell lines based on two tissue sources, i.e. mouse fetal liver and adult bone marrow. To obtain cell lines, retroviral vectors encoding an estrogen-regulated Hox gene were introduced into progenitor cells derived from both tissues. These transduced cells can be expanded in their non-differentiated state for extended periods and upon estrogen removal, these cells differentiate into MCs in the presence of IL-3 and SCF. Resulting mast cells are functionally comparable to BM-derived MCs, initiating degranulation upon IgE cross-linking. Likewise, these MCs express MC-specific proteases such as chymase 1 and MCPT4. In conclusion, our findings highlight the efficacy of estrogen-regulated Hox genes in targeting MC progenitors in both fetal liver and adult BM. The established cell lines serve as reliable tools for studying MC biology, ontogeny and, possibly, disease conditions, such as allergies.

Self-sufficient primary natural killer cells engineered to express T cell receptors and interleukin-15 exhibit improved effector function and persistence.

NK cells can be genetically engineered to express a transgenic T-cell receptor (TCR). This approach offers an alternative strategy to target heterogenous tumors, as NK:TCR cells can eradicate both tumor cells with high expression of HLA class I and antigen of interest or HLA class I negative tumors. Expansion and survival of NK cells relies on the presence of IL-15. Therefore, autonomous production of IL-15 by NK:TCR cells might improve functional persistence of NK cells. Here we present an optimized NK:TCR product harnessed with a construct encoding for soluble IL-15 (NK:TCR/IL-15), to support their proliferation, persistence and cytotoxic capabilities. Expression of tumor-specific TCRs in peripheral blood derived NK-cells was achieved following retroviral transduction. NK:TCR/IL-15 cells were compared with NK:TCR cells for autonomous cytokine production, proliferation and survival. NK:BOB1-TCR/IL-15 cells, expressing a HLA-B*07:02-restricted TCR against BOB1, a B-cell lineage specific transcription factor highly expressed in all B-cell malignancies, were compared with control NK:BOB1-TCR and NK:CMV-TCR/IL-15 cells for effector function against TCR antigen positive malignant B-cell lines in vitro and in vivo. Viral incorporation of the interleukin-15 gene into engineered NK:TCR cells was feasible and high expression of the TCR was maintained, resulting in pure NK:TCR/IL-15 cell products generated from peripheral blood of multiple donors. Self-sufficient secretion of IL-15 by NK:TCR cells enables engineered NK cells to proliferate in vitro without addition of extra cytokines. NK:TCR/IL-15 demonstrated a marked enhancement of TCR-mediated cytotoxicity as well as enhanced NK-mediated cytotoxicity resulting in improved persistence and performance of NK:BOB1-TCR/IL-15 cells in an orthotopic multiple myeloma mouse model. However, in contrast to prolonged anti-tumor reactivity by NK:BOB1-TCR/IL-15, we observed in one of the experiments an accumulation of NK:BOB1-TCR/IL-15 cells in several organs of treated mice, leading to unexpected death 30 days post-NK infusion. This study showed that NK:TCR/IL-15 cells secrete low levels of IL-15 and can proliferate in an environment lacking cytokines. Repeated in vitro and in vivo experiments confirmed the effectiveness and target specificity of our product, in which addition of IL-15 supports TCR- and NK-mediated cytotoxicity.

235 IL-4/13 Blocking Peptide (KROS-401) Inhibits M2 Macrophage Polarization in vitro and Demonstrates Anti-tumor Activity in a Murine Model of Glioblastoma

INTRODUCTION: Glioblastoma (GBM) is the most aggressive primary brain malignancy with a median survival of 14 months. Tumor-associated macrophages (TAMs) comprise up to 40% of the GBM tumor mass and are significant enablers of an immunosuppressive tumor microenvironment (TME), limiting immunotherapeutic efficacy. TAMs are generally classified as M2 macrophages that demonstrate a pro-tumor phenotype and increased CD206 surface marker expression. Reducing the M2 macrophage population in tumors has shown benefit in preclinical studies across various cancers. Interleukins (IL)-4 and -13 both play a role in polarizing macrophages to an M2 state. We developed a peptide inhibitor (KROS-401) that targets the shared IL-4Ra subunit of the IL-4 and -13 receptor complex to inhibit macrophage polarization to an M2 phenotype and reprogram the immunosuppressive TME. METHODS: Human peripheral blood mononuclear cell (PBMC)-derived macrophages were isolated and treated with KROS-401 in the presence of IL-4 and IL-13 cytokines. M2 (CD206) surface markers were assessed by flow cytometry. The efficacy of KROS-401 peptide was examined using an intracranially implanted syngeneic murine model with luciferase-expressing GL261, a glioma cell line. Mice were inspected daily for survival and tumor growth was tracked by non-invasive in vivo bioluminescent imaging (BLI). RESULTS: Human PBMC-derived macrophages treated with KROS-401 displayed a dose-dependent decrease in M2 (CD206) cell surface markers. KROS-401 peptide inhibitor demonstrated anti-tumor activity in GL261 glioma-bearing mice with a significantly increased probability of survival compared to control (p = 0.0046) with a median survival of &gt;40 days versus 27 days, respectively. CONCLUSIONS: KROS-401 inhibits M2 polarization of human macrophages in vitro and tumor growth in vivo. These findings highlight this IL-4/IL-13 peptide inhibitor as a potential immunomodulator of the TME for the treatment of GBM.

Abstract 7307: Silibinin regulates glucocorticoid signaling via mast cells: Potential treatment of androgen-resistant prostate cancer

Abstract Prostate cancer (PCa) is the second most common cancer in American men. The American Cancer Society estimates that in 2023 there have been ~288,300 new cases of PCa and ~34,700 deaths from PCa in the United States. We previously showed that silibinin (SB; a natural flavonolignan from milk thistle seeds) is an effective therapeutic against PCa that inhibits cell growth and mitogenic cell survival via EGFR, IGFR-1, and NFκB signaling. However, the effect of SB on the tumor immunological microenvironment has not been elucidated. Mast cells (MCs) are archetypal solider of the immune system. The dynamics of PCa and MCs are complex, where they may contribute to tumor transformation/progression/regression; furthermore, their role in PCa is poorly understood. To address this gap and understand the role of SB in MC regulation, MCs were derived from the bone marrow (BMMCs) of C57BL/6 mice. BMMCs were generated in the presence of IL-3 and SCF, and were confirmed to be BMMCs using flow cytometry (dual staining: cKit/Fc€RI). Thereafter, the BMMCs were exposed to different doses of SB (25-100 µM) and two concentrations (25 µM; SB 25 and 100 µM; SB 100) were selected for further experiments. BMMCs treated with SB 25, SB 100, and untreated (control) were subjected to proteomic analysis using LCMS on Fusion Lumos mass spectrometer. A total of 3575 proteins were identified using the annotated mouse proteome. Statistical analysis was performed using ANOVA followed by Fisher’s posthoc analysis (p&amp;lt;0.05, FDR&amp;lt;0.01) and 166 proteins were found to be have statistically significant differential expression amongst the three groups (n=4/group). These 166 proteins were selected for further pathway analysis using Ingenuity Pathway Analysis (IPA; Qiagen). Only pathways specifically demonstrated experimentally in prostatic tissues/cells were selected for further analysis. Important nodes found for SB regulation of MCs in PCa were androgen receptor (AR), transmembrane serine protease (TMPRSS), and NK3 Homeobox 1 (NKX3-1). AR, TMPRSS, and NkX3-1 are well established in PCA. Most important pathway found was glucocorticoid receptor (GR) signaling; nuclear receptor subfamily 3 group C member 1 (NR3C1) and HS90 were the most important proteins identified in GR signaling. GR signaling may cause androgen deprivation therapy (ADT)-resistance by directly activating AR-target genes (including TMPRSS2) and/or activating an independent transcriptome. NR3C1 has been shown to share target specificity with AR and is highly upregulated in the resistant tumors. Thus, SB could play an important therapeutic role, specifically in ADT-resistant tumors via regulation of MCs. Further studies are warranted to delineate these mechanisms. Understanding these mechanistic could also potentially aid to decipher a general mechanism of resistance to antiandrogens and potential of SB in treating ADT-resistant tumors. Citation Format: Neha Mishra, Sandeep Paudel, Komal Raina, Paul Maroni, Chapla Agarwal, Rajesh Agarwal. Silibinin regulates glucocorticoid signaling via mast cells: Potential treatment of androgen-resistant prostate cancer [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 7307.

Abstract 1240: Enhancing NK cell function in the ‘cold’ tumor microenvironment of prostate cancer with a novel tri-specific killer engager

Abstract Introduction: Natural killer (NK) cells are associated with good prognosis in patients with metastatic castration-resistant prostate cancer (mCRPC). However, NK cell function is hindered in the immunosuppressive and hypoxic tumor microenvironment (TME) of mCRPC. To improve NK cell-mediated responses against mCRPC, we designed a novel Tri-specific Killer Engager (TriKE®) that engages with NK cell activating receptor CD16, binds to prostate-specific membrane antigen (PSMA) that is highly and specifically expressed on mCRPC, and has an interleukin (IL)-15 moiety that is essential for NK cell survival, proliferation, and priming. Methods: PSMA TriKE was produced using the mammalian expression system and tested using healthy donor and prostate cancer patient-derived NK cells. Flow cytometry-based functional and dye dilution proliferation assays were used to compare activation and proliferation of NK cells treated with PSMA TriKE or IL-15. NK cell cytolytic capacity against C4-2 cells, a PSMA-expressing prostate cancer line, was measured using IncuCyte live cell imaging. In various assays, hypoxic (1% oxygen) culture condition and cytokine-induced myeloid-derived suppressor cells (MDSC) were incorporated to better examine PSMA TriKE function in the physiological setting of mCRPC. In vivo testing of the PSMA TriKE was performed using C4-2 xenograft model and expanded NK cells in NSG mice. Results: PSMA TriKE significantly enhanced expansion of peripheral blood NK cells derived from healthy donors up to 8-fold. Additionally, PSMA TriKE induced significantly higher NK cell degranulation and intracellular IFNγ and TNFα buildup, when compared to IL-15 treatment, after incubation with C4-2 cells. Responses of NK cells derived from prostate cancer patients were equivalent to healthy controls. Although NK cell activation was not observed against PSMA knockout (KO) C4-2, indicating specificity of PSMA TriKE treatment, bystander killing of PSMA-KO C4-2 was achieved with PSMA TriKE treatment when wildtype C4-2 cells were cocultured. This suggests potential PSMA TriKE benefit in controlling tumor antigen escape, through natural cytotoxicity once primed. In settings that mimic the TME of mCRPC, NK cells treated with PSMA TriKE in prolonged exposure to hypoxia showed retention of cytotoxicity against C4-2 while IL-15 treated NK cells showed greatly impaired cytotoxicity. Similarly, MDSC suppressed NK cell cytotoxicity in the presence of IL-15, but PSMA TriKE treatment abrogated MDSC-induced suppression. Finally, PSMA TriKE enhanced tumor control and improved survival of mice as compared to IL-15 and no treatment groups in vivo. Conclusion: PSMA TriKE demonstrates potential in overcoming suppression of NK cells in the TME of mCRPC and is a promising candidate for advanced prostate cancer therapy. Citation Format: Shee Kwan Phung, Yvette Soignier, Nicholas Zorko, Rhett L. Waller, Josh Walker, Trygve Nelson, Carly Selleck, Laura Bendzick, Philippa Kennedy, Jeffrey S. Miller, Martin Felices. Enhancing NK cell function in the ‘cold’ tumor microenvironment of prostate cancer with a novel tri-specific killer engager [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 1240.

Abstract 18: The polyamine-hypusine axis is a promising avenue to improve T-cell metabolism and persistence for adoptive cell therapy

Abstract There are significant barriers to the application of Adoptive Cell Therapy (ACT) to many cancer types. One of these barriers is a result of poor metabolic fitness of T cells, leading to poor proliferation, persistence, and dampened anti-tumor function. Leveraging T-cell metabolism to improve their function is becoming increasingly important to make significant strides in immunotherapy. Stat5a has been shown to be a master regulator of energy and metabolism in T cells, highlighting it as a promising avenue to improve T-cell metabolism for ACT. We have established that the expression of Constitutively Active Signal Transducer and Activator of Transcription 5A (CASTAT5) on tumor-specific CD4+ T cells improves their persistence, polyfunctionality, and anti-tumor effects in a mouse model. This study further examines Stat5a and its downstream metabolic targets in the context of ACT. We carried out scRNAseq analysis and found that Stat5a directly interacts with genes involved in polyamine metabolism. More specifically, Stat5a activation increases the expression of ornithine decarboxylase (Odc1), spermidine synthase (Srm), deoxyhypusine synthase (Dhps), and deoxyhypusine hydroxylase (Dohh) in a subset of CD4+ T cells expressing CASTAT5. Cleavage Under Targets and Tagmentation (Cut&amp;Tag) analysis of histone H3K27ac also demonstrated increased H3K27ac at promoter and enhancer regions of polyamine pathway genes in CASTAT5 compared to control CD4+ T cells. To further examine the function of Stat5a, the murine pro-B cell line, Ba/F3, is being used as a model to study Stat5a-mediated signaling. We have found that upon withdrawal of IL-3 from Ba/F3 cells, Stat5a activation is significantly downregulated. Our scRNA-seq-based metabolic flux estimation showed a significant reduction in metabolic fluxes and related genes, including polyamines, following IL-3 withdrawal. Correspondingly, Stat5a ChIP-Seq and Cut&amp;Tag analyses of H3K27ac revealed Stat5a binding to active enhancer regions in the presence of IL-3 that are lost following its withdrawal. Untargeted metabolomics confirmed the marked Stat5a-mediated reduction in metabolite abundance after IL-3 deprivation, in a time-dependent manner. The polyamine-hypusine axis revealed in our studies is a promising avenue to improve T-cell function. This axis has been shown to regulate T-cell function, and potentially modulate mitochondrial respiration and T-cell activation. Hence, our studies have identified polyamine supplementation and gene modulation as promising strategies to improve the metabolism of Adoptive T cells in a Stat5a-mediated manner. Further studies will evaluate the effectiveness of this avenue in improving T-cell function, improving their efficacy for ACT, and improving patient outcomes. Citation Format: Mercy Kehinde-Ige, Ogacheko Okoko, Gang Zhou, Huidong Shi. The polyamine-hypusine axis is a promising avenue to improve T-cell metabolism and persistence for adoptive cell therapy [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 18.

Abstract 1332: Allogeneic CD19-directed CAR-iNKT cells and their phenotypic subsets for the treatment of CD19+ hematological malignancies

Abstract Invariant Natural Killer T (iNKT) cells are a unique subset of innate lymphocytes, constituting &amp;lt;1% of human T cells. iNKT cells express a semi-invariant TCR (iTCR) recognizing glycolipids presented by the monomorphic, MHC-like molecule CD1d. Previous studies indicate that due to distinctive TCR constitution and antigen recognition properties, iNKT cells do not induce acute graft-versus-host disease. Based on the CD4 and CD8 expression, mature human iNKT cells can be classified into CD4+CD8-, CD4-CD8- &amp; CD4-CD8+ subsets with overlapping and distinct functions. The functional profiling of CAR19-iNKT cell subsets serves the dual purpose of ensuring their safety and efficacy as a therapeutic intervention. Here we characterized the phenotypic and functional profile of CD4+ and CD4- CAR19-iNKT cells. iNKT cells were isolated with &amp;gt;99% purity from healthy donors' peripheral blood and were transduced with a CD19 CAR-encoding 3rd generation lentivirus. After expansion, the CAR19-iNKT cells were cryopreserved and later analyzed post-thawing. Differential expression of CD27 and PD1 was noted in CAR+CD4+ and CAR+CD4- iNKT cells compared to other markers. For functional profiling, CAR+CD4+ iNKT cells were positively selected, and 24h cytotoxicity assays were performed using several tumor cell lines including SEM, Ramos and C1R-CD1d (+/- α-GalCer). The CAR+CD4- iNKT cells exhibited superior cytotoxicity to multiple tumor cell lines compared to that of CAR+CD4+ iNKT cells from two donors. However, both subsets lysed α-GalCer pulsed C1R-CD1d cells in a comparable manner indicating the potential of these subsets to recognize antigen through the iTCR. Subsequently, we assessed the proliferation ability of the CAR+CD4+ and CAR+CD4- subsets by exposing the cells to three rounds of stimulation, 24h apart, using SEM (CD19+CD1d-) or K562 (CD19-CD1d-) tumor cells with or without IL-15. Proliferation was assessed seven days following the first stimulation. The CAR+CD4+ subset of CAR19-iNKT cells demonstrated faster proliferation than CAR+CD4- cells in the presence of IL-15 after repeated exposure to tumor cells. Ongoing RNA seq analysis of CAR+CD4+/CAR+CD4- cells will further elucidate differences between these subsets. The outcomes of these studies have shown encouraging results, indicating the potential benefit of having diverse subsets among CAR19-iNKT cells for treating CD19+ cancers. The therapeutic potential of CAR+CD4+ iNKT cell subset could be enhanced to match that of CAR+CD4- subset with the use of α-GalCer. In summary, inclusion of both CD4+ and CD4- iNKT cells is critical for the functionality of allogeneic CAR-iNKT cell therapy. Extensive characterization is crucial for clinical translation, but additional research, including preclinical and clinical trials, is essential to determine the safety and effectiveness of CAR19-iNKT cell therapy in real-world applications. Citation Format: Kanagaraju Ponnusamy, Simon Poon, Nicole van der Weerden, Robson Dossa, Michael J. Baker, Mini Bharathan, Anastasios Karadimitris. Allogeneic CD19-directed CAR-iNKT cells and their phenotypic subsets for the treatment of CD19+ hematological malignancies [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 1332.

Abstract 57: Ibrutinib improves chimeric antigen receptor T cell control of leukemia by inhibiting myeloid-derived suppressor cells

Abstract Background: In patients with chronic lymphocytic leukemia (CLL), we and others have shown that the addition of the BTK inhibitor ibrutinib to CART cells increases the rates of durable complete responses. The mechanism for this remains unknown. Lymphodepletion (LD) is considered critical for CART cell therapy success, yet emergency myelopoiesis during recovery from LD may induce a surge of myeloid-derived suppressor cells (MDSC), particularly in patients with advanced cancer. BTK inhibition has been shown to inhibit MDSC function in vitro. We therefore hypothesized that administration of ibrutinib during and following LD could reduce MDSC-mediated suppression of CART cells and thereby improve CART cell outcomes. Methods: To explore the effects of ibrutinib on human MDSCs, we engineered suppressive monocytes through in vitro culture of CD14+ cells in the presence of IL-6 and GM-CSF. We added ibrutinib to the culture on Days 0-4 and compared the ability of the monocytes to inhibit proliferation of human CAR-T cells. To model CLL treatment with CART in immunocompetent mice, we used the Em-TCL1 adaptive transfer model of CLL. Mice were treated with ibrutinib (I), cyclophosphamide and fludarabine (FC), or ibrutinib + FC (FC+I). MDSCs were isolated from these mice for in vitro function studies. In subsequent experiments mice were also treated with syngeneic CART19 with or without FC or FC+I. Results: In vitro generated human MDSC suppressed CART19 function, and this was prevented by pre-treatment of MDSC with ibrutinib. Myeloid cells from the spleens of CLL-bearing mice inhibited syngeneic CART19 function ex vivo regardless of treatment with FC or I alone, but myeloid cells harvested from CLL-bearing mice treated with FC+I lost suppressive function. Finally, mice treated with CART19 after a LD regimen resembling that in our recently reported clinical trial (FC+I) showed a survival advantage over all other groups. Conclusions: BTK inhibition with ibrutinib prevents myeloid cell suppression of CART cells in vitro in human and murine systems. When combined with lymphodepleting chemotherapy (FC), ibrutinib enhances CART cell control of CLL in vivo, possibly by preventing MDSC-mediated suppression of CART cells. Citation Format: Benjamin F. Frost, Olga Shestova, Feng Shen, Chia Sharpe, John C. Byrd, Saar I. Gill. Ibrutinib improves chimeric antigen receptor T cell control of leukemia by inhibiting myeloid-derived suppressor cells [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 57.

IL7 increases targeted lipid nanoparticle–mediated mRNA expression in T cells in vitro and in vivo by enhancing T cell protein translation

The use of lipid nanoparticles (LNP) to encapsulate and deliver mRNA has become an important therapeutic advance. In addition to vaccines, LNP-mRNA can be used in many other applications. For example, targeting the LNP with anti-CD5 antibodies (CD5/tLNP) can allow for efficient delivery of mRNA payloads to T cells to express protein. As the percentage of protein expressing T cells induced by an intravenous injection of CD5/tLNP is relatively low (4-20%), our goal was to find ways to increase mRNA-induced translation efficiency. We showed that T cell activation using an anti-CD3 antibody improved protein expression after CD5/tLNP transfection in vitro but not in vivo. T cell health and activation can be increased with cytokines, therefore, using mCherry mRNA as a reporter, we found that culturing either mouse or human T cells with the cytokine IL7 significantly improved protein expression of delivered mRNA in both CD4+ and CD8+ T cells in vitro. By pre-treating mice with systemic IL7 followed by tLNP administration, we observed significantly increased mCherry protein expression by T cells in vivo. Transcriptomic analysis of mouse T cells treated with IL7 in vitro revealed enhanced genomic pathways associated with protein translation. Improved translational ability was demonstrated by showing increased levels of protein expression after electroporation with mCherry mRNA in T cells cultured in the presence of IL7, but not with IL2 or IL15. These data show that IL7 selectively increases protein translation in T cells, and this property can be used to improve expression of tLNP-delivered mRNA in vivo.

Bacterial antigens and asthma: a comparative study of common respiratory pathogenic bacteria

Objective: In a previous study we have shown that, in the presence of interleukin (IL)-33, repeated, per-nasal challenge of murine airways with Streptococcus pneumoniae (S. pneumoniae) organisms induces human asthma-like airways inflammation. It is not clear, however, whether this effect is unique or manifest in response to other common respiratory pathogens.Methods: To explore this, airways of BALB/c mice were repeatedly challenged per-nasally with formaldehyde-inactivated bacterial bodies in the presence or absence of murine recombinant IL-33. Serum concentrations of S.pneumoniae, Moraxella catarrhalis (M.catarrhalis) and Haemophilus influenzae (H.influenzae) lysates-specific IgE were measured in patients with asthma and control subjects.Results: We showed that in the presence of IL-33, repeated, per-nasal airways exposure to the bodies of these bacteria induced airways hyperresponsiveness (AHR) in the experimental mice. This was accompanied by cellular infiltration into bronchoalveolar lavage fluid (BALF), eosinophilic infiltration and mucous hypertrophy of the lung tissue, with elevated local expression of some type 2 cytokines and elevated, specific IgG and IgE in the serum. The precise characteristics of the inflammation evoked by exposure to each bacterial species were distinguishable.Conclusions: These results suggest that in the certain circumstances, inhaled or commensal bacterial body antigens of both Gram-positive (S. pneumoniae) and Gram-negative (M. catarrhalis and H. influenzae) respiratory tract bacteria may initiate type 2 inflammation typical of asthma in the airways. In addition, we demonstrated that human asthmatic patients manifest elevated serum concentrations of M.catarrhalis- and H.influenzae-specific IgE.

Building a Better Defense: Expanding and Improving Natural Killer Cells for Adoptive Cell Therapy.

Natural killer (NK) cells have gained attention as a promising adoptive cell therapy platform for their potential to improve cancer treatments. NK cells offer distinct advantages over T-cells, including major histocompatibility complex class I (MHC-I)-independent tumor recognition and low risk of toxicity, even in an allogeneic setting. Despite this tremendous potential, challenges persist, such as limited in vivo persistence, reduced tumor infiltration, and low absolute NK cell numbers. This review outlines several strategies aiming to overcome these challenges. The developed strategies include optimizing NK cell expansion methods and improving NK cell antitumor responses by cytokine stimulation and genetic manipulations. Using K562 cells expressing membrane IL-15 or IL-21 with or without additional activating ligands like 4-1BBL allows "massive" NK cell expansion and makes multiple cell dosing and "off-the-shelf" efforts feasible. Further improvements in NK cell function can be reached by inducing memory-like NK cells, developing chimeric antigen receptor (CAR)-NK cells, or isolating NK-cell-based tumor-infiltrating lymphocytes (TILs). Memory-like NK cells demonstrate higher in vivo persistence and cytotoxicity, with early clinical trials demonstrating safety and promising efficacy. Recent trials using CAR-NK cells have also demonstrated a lack of any major toxicity, including cytokine release syndrome, and, yet, promising clinical activity. Recent data support that the presence of TIL-NK cells is associated with improved overall patient survival in different types of solid tumors such as head and neck, colorectal, breast, and gastric carcinomas, among the most significant. In conclusion, this review presents insights into the diverse strategies available for NK cell expansion, including the roles played by various cytokines, feeder cells, and culture material in influencing the activation phenotype, telomere length, and cytotoxic potential of expanded NK cells. Notably, genetically modified K562 cells have demonstrated significant efficacy in promoting NK cell expansion. Furthermore, culturing NK cells with IL-2 and IL-15 has been shown to improve expansion rates, while the presence of IL-12 and IL-21 has been linked to enhanced cytotoxic function. Overall, this review provides an overview of NK cell expansion methodologies, highlighting the current landscape of clinical trials and the key advancements to enhance NK-cell-based adoptive cell therapy.

IL-21 conditions antigen-presenting human γδ T-cells to promote IL-10 expression in naïve and memory CD4+ T-cells.

Direct interaction between T-cells exerts a major influence on tissue immunity and inflammation across multiple body sites including the human gut, which is highly enriched in 'unconventional' lymphocytes such as γδ T-cells. We previously reported that microbial activation of human Vγ9/Vδ2+ γδ T-cells in the presence of the mucosal damage-associated cytokine IL-15 confers the ability to promote epithelial barrier defence, specifically via induction of IL-22 expression in conventional CD4+ T-cells. In the current report, we assessed whether other cytokines enriched in the gut milieu also functionally influence microbe-responsive Vγ9/Vδ2 T-cells. When cultured in the presence of IL-21, Vγ9/Vδ2 T-cells acquired the ability to induce expression of the immunoregulatory cytokine IL-10 in both naïve and memory CD4+ T-cells, at levels surpassing those induced by monocytes or monocyte-derived DCs. These findings identify an unexpected influence of IL-21 on Vγ9/Vδ2 T-cell modulation of CD4+ T-cell responses. Further analyses suggested a possible role for CD30L and/or CD40L reverse signalling in mediating IL-10 induction by IL-21 conditioned Vγ9/Vδ2 T-cells. Our findings indicate that the local microenvironment exerts a profound influence on Vγ9/Vδ2 T-cell responses to microbial challenge, leading to induction of distinct functional profiles among CD4+ T-cells that may influence inflammatory events at mucosal surfaces. Targeting these novel pathways may offer therapeutic benefit in disorders such as inflammatory bowel disease.