Activation Of pSTAT3 Research Articles

Abstract 2972: Preclinical characterization of SAR445877, an anti-PD-1 antibody-IL-15 mutein fusion protein with robust anti-tumor efficacy as monotherapy and in combination with PD-L1 blockade

Abstract Immune checkpoint blockade elicits durable anti-cancer responses in the clinic, however a large proportion of patients do not benefit from treatment. A major unmet medical need in immuno-oncology (IO) is extending the benefits of these therapies to patients who never experience tumor regression (primary resistance) or who derive initial benefit followed by tumor progression (acquired resistance). To improve clinical benefits of anti-PD-1 antibody, we generated SAR445877 (formerly KD050), which is an antibody cytokine fusion molecule that combines a human anti-PD-1 antibody with a mutated fusion of human IL15 and human IL15Rα sushi domain. SAR445877 binds to human PD-1 and inhibits immunosuppressive signaling through the PD-1/PD-L1 pathway. The IL15-IL15Rα fusion contains a single amino acid mutation that confers reduced potency of IL2/15Rβγ stimulation relative to wild type IL-15, reduces binding to IL-2Rβ expressing HEK 293 cells, (EC50: >108 nM vs 4.05nM) and decreases pSTAT5 activation in HEK blue IL-2 reporter assay by more than 5-fold. Through its IL15-IL15Rα fusion moiety, SAR445877 stimulates cells expressing IL2/15Rβγ with much weaker activity than wild type IL-15 when measured by CTLL-2 cell proliferation in vitro (EC50: 398.8nM vs 1.68nM). Fusion of IL-15 to anti-PD-1 antibody mediates cis-activation of human PD-1+ cells, including both PD-1+ HEK blue reporter cell line and human primary T cells, with higher potency compared to non-targeted IL-15. This cis-activation could result in expansion and activation of antigen-specific CD8+ T cells with improved activity in the tumor microenvironment compared to non-targeted IL-15. Antitumor efficacy of SAR445877 was explored in the CT26 colorectal cancer model using the clinical candidate. Transgenic mice expressing human PD-1 and PD-L1 were implanted with CT26 tumors expressing human PD-L1 and treated with SAR445877. SAR445877 displayed a more potent antitumor efficacy than pembrolizumab. Further, treatment with SAR445877 increased the CD8/CD4 T cell ratio and significantly increased the percentage of effector memory CD8 T cells in tumors. In anti-PD-L1 antibody resistant Pan02 syngeneic tumor model, a murine surrogate molecule produced a remarkable antitumor activity and was well tolerated. Combination treatment of murine surrogate with anti-mPD-L1 displayed greater antitumor activity than single agent treatment (TGI = 99.30% vs 78.78%). In summary, SAR445877 can target potency-reduced IL-15 to PD-1+ T cells and induce cis-activation of T cells. SAR445877 exhibited potent anti-tumor efficacy in PD-1 resistant preclinical model with good tolerability. These results support further evaluation of SAR445877 in a phase I clinical trial (ClinicalTrials.gov #NCT05584670). Citation Format: Marie Bernardo, Yu-an Zhang, Dan Lu, Stella Martomo, Fatima Menas, Chen Zhu, Raymond Perez, Jeegar Patel, Donald Shaffer, Xiangming Li. Preclinical characterization of SAR445877, an anti-PD-1 antibody-IL-15 mutein fusion protein with robust anti-tumor efficacy as monotherapy and in combination with PD-L1 blockade [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 2972.

Valproic acid inhibits cell growth in both MCF-7 and MDA-MB231 cells by triggering different responses in a cell type-specific manner

BackgroundBreast cancer is the second leading cause of death among women after lung cancer. Despite the improvement in prevention and in therapy, breast cancer still remains a threat, both for pre- and postmenopausal women, due to the development of drug resistance. To counteract that, novel agents regulating gene expression have been studied in both hematologic and solid tumors. The Histone Deacetylase (HDAC) inhibitor Valproic Acid (VA), used for epilepsy and other neuropsychiatric diseases, has been demonstrated a strong antitumoral and cytostatic activity. In this study, we tested the effects of Valproic Acid on the signaling pathways involved in breast cancer cells viability, apoptosis and in Reactive Oxygen Species (ROS) production using ER-α positive MCF-7 and triple negative MDA-MB-231 cells.MethodsCell proliferation assay was performed by MTT Cell cycle, ROS levels and apoptosis were analyzed by flow cytometry, protein levels were detected by Western Blotting.ResultsCell treatment with Valproic Acid reduced cell proliferation and induced G0/G1 cell cycle arrest in MCF-7 and G2/M block in MDA-MB-231 cells. In addition, in both cells the drug enhanced the generation of ROS by the mitochondria. In MCF-7 treated cells, it has been observed a reduction in mitochondrial membrane potential, a down regulation of the anti-apoptotic marker Bcl-2 and an increase of Bax and Bad, leading to release of cytochrome C and PARP cleavage. Less consistent effects are recorded in MDA-MB-231 cells, in which the greater production of ROS, compared to MCF-7cells, involves an inflammatory response (activation of p-STAT3, increased levels of COX2).ConclusionsOur results have demonstrated that in MCF-7 cells the Valproic Acid is a suitable drug to arrest cell growth, to address apoptosis and mitochondrial perturbations, all factors that are important in determining cell fate and health. In a triple negative MDA-MB 231 cells, valproate directs the cells towards the inflammatory response with a sustained expression of antioxidant enzymes. Overall, the not always unequivocal data between the two cellular phenotypes indicate that further studies are needed to better define the use of the drug, also in combination with other chemotherapy, in the treatment of breast tumors.

P034 A common IL2RA polymorphism alters natural killer cell immunophenotype and function in Crohn’s disease, with implications for IL-2 based therapy

Abstract Background The single nucleotide polymorphism (SNP) rs61839660 lies within the IL2RA (CD25) intronic enhancer and has been identified as a causal variant in Crohn’s disease (CD), with a heterozygote frequency of 16.8% in a European population. CD25 is the high-affinity receptor for IL-2, and is constitutively expressed on regulatory T cells (Tregs). Low-dose IL-2 (LD-IL2) is under investigation in IBD, under the premise that it will expand a group of tolerising Tregs. However, finding a therapeutic dose which activates Tregs without activating effector T cells (Teffs) has proved challenging and activation of CD56dim NK cells has been linked to adverse events in trial subjects. We have demonstrated that the rs61839660 risk (T) allele carriers exhibit higher CD4+ T cell CD25 expression, enhanced pSTAT5 activation on stimulation with IL-2, and greater Teff release of pro-inflammatory cytokines. We sought to understand the impact of the risk allele on NK cell immunophenotype and function. Methods We recruited CD patients homozygous major allele (CC), or heterozygous (CT) at the rs61839660 locus. We extracted peripheral blood mononuclear cells and flow-sorted CD56dim (cytotoxic) and CD56bright (regulatory) NK subsets. Cells were stimulated with IL-2, then stained for intracellular pSTAT5. To assess cytotoxicity, NK cells were rested in media either with or without IL-2, before plating with CFSE-labelled K562 target cells. The proportion of K562 cells positive for dead cell marker was assessed for each condition. Results There was no difference in CD phenotype or severity between groups, in terms of age at diagnosis, sex distribution, presence of perianal disease or the proportion requiring surgery. CD25 expression was significantly enhanced on CD56Bright NK cells in CT subjects compared to CC subjects (1b). Enhanced CD25 expression was also seen in CD56Dim NK cells, though this did not reach statistical significance (1a). The concentration of IL-2 required to activate 50% intracellular STAT5 was lower in CT subjects’ CD56Bright NK cells compared to those from CC subjects (21.5IU/ml vs. 132.4IU/ml, p=0.039). The cytotoxicity of CT subjects’ CD56dim NK cells was significantly enhanced following exposure to IL-2, compared to CC subjects (1c). Conclusion Our findings suggest that risk (T) allele carriers have enhanced responsiveness to IL-2 signalling in NK cells, mediated by increased expression of CD25. We hypothesise that these subjects would be at greater risk of adverse events on exposure to LD-IL2, through enhanced CD56Dim NK cytotoxicity. Our results suggest that screening of subjects entering trials of IL-2-based therapy for the rs61839660 risk variant should be considered, as the threshold for adverse events in these subjects may be lower.

SOCS2 protects against chemical-induced hepatocellular carcinoma progression by modulating inflammation and cell proliferation in the liver

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers worldwide, but the precise intracellular mechanisms underlying the progression of this inflammation associated cancer are not well established. SOCS2 protein plays an important role in the carcinogenesis of different tumors by regulating cytokine signalling through the JAK/STAT axis. However, its role in HCC is unclear. Here, we investigate the role of SOCS2 in HCC progression and its potential as HCC biomarker. The effects of SOCS2 in HCC progression were evaluated in an experimental model of diethylnitrosamine (DEN)-induced HCC in C57BL/6 and SOCS2 deficient mice, in cultured hepatic cells, and in liver samples from HCC patients. Mice lacking SOCS2 showed higher liver tumor burden with increased malignancy grade, inflammation, fibrosis, and proliferation than their controls. Protein and gene expression analysis reported higher pSTAT5 and pSTAT3 activation, upregulation of different proteins involved in survival and proliferation, and increased levels of proinflammatory and pro-tumoral mediators in the absence of SOCS2. Clinically relevant, downregulated expression of SOCS2 was found in neoplasia from HCC patients compared to healthy liver tissue, correlating with the malignancy grade. In summary, our data show that lack of SOCS2 increases susceptibility to chemical-induced HCC and suggest the tumor suppressor role of this protein by regulating the oncogenic and inflammatory responses mediated by STAT5 and STAT3 in the liver. Hence, SOCS2 emerges as an attractive target molecule and potential biomarker to deepen in the study of HCC treatment.

Proteins from Modern and Ancient Wheat Cultivars: Impact on Immune Cells of Healthy Individuals and Patients with NCGS.

In non-celiac gluten sensitivity (NCGS), the elimination of wheat results in a clear symptom improvement, but gluten has still not been proven as (the sole) trigger. Due to the increase in the prevalence of gluten-related diseases, the breeding of high-performance wheat cultivars is discussed as a trigger. To analyze the immune stimulation and signal pathways, the immune cells of healthy subjects and patients with NCGS were stimulated with gliadins from wheat, and the expression and secretion of interleukin 1ß (IL1ß) and interleukin 6 (IL6) were studied. To determine the impact of wheat breeding, the monocyte cell line THP1 and human immune cells were stimulated with gliadin, glutenin, and albumin/globulin fractions of ancient and modern cereals, and expression of inflammatory molecules was checked. Immune cells of patients with NCGS showed an increased expression of IL1ß and IL6 after stimulation with gliadins compared to immune cells of healthy controls. Gliadins caused a strong activation of P-STAT3 in immune cells of healthy controls, and inhibitors of JAK and NFκB pathways considerably reduced this response. In addition to gliadins, we further showed that glutenins and albumin/globulins from all wheat cultivars from the last century, and especially from einkorn and spelt, also markedly induced the expression of inflammatory genes in THP1 and human immune cells. There was no correlation between enhanced immune stimulation and ancient or modern cultivars. This does not support the hypothesis that modern wheat breeding is responsible for the increase in gluten-related diseases. An altered immune situation is suggested in patients with NCGS.

Abstract 20 A Rapid and Sensitive IL-3-Based Assay Reveals How Various Pre-Processing Conditions Affect the Potency of Hematopoietic Stem Cells in Fresh Cord Blood Units

IntroductionOptimized procedures to collect, process, and store cord blood (CB) units are crucial to ensure stem cell product quality; however, current methods to assess hematopoietic stem cell (HSC) potency are time-consuming or lack sensitivity. Therefore, developing methods that rapidly and accurately portray HSC potency in fresh blood is important to help optimize clinical outcomes.ObjectiveWe sought to adapt to fresh CB a potency assay previously developed for HSCs contained in cryopreserved CB [Simard et al. Transfusion. 2019;59(6):2074-2083.]. We next used the assay to evaluate the impact of various CB processing conditions on HSC potency.MethodsFresh CB units were exposed to various pre-processing storage conditions (ie, temperature changes and various anticoagulants). Units were then analyzed at various time points up to 96 hours using traditional iShage and colony-forming assays, in parallel with the IL-3-based potency assay.ResultsFor CB units maintained at room temperature (RT), the potency measured with the IL-3-based assay (ie, the proportion of IL-3-responsive CD34+ cells as measured by pStat5 activation) linearly decreased over time. A potency of 69% was observed when tested within 0-24 hours, compared with 56% and 40% in the 24-48–hour and the 48-72–hour groups, respectively. In addition, the IL-3-based assay showed that pre-processing storage at 4°C prevented this loss of HSC potency. By contrast, the HSC count by iShage and the CFU numbers remained unchanged with time or temperature variations.DiscussionThe newly developed IL3-based assay appears reliable and sensitive to characterize the potency of CD34+ cells in fresh CB. In addition, this assay indicated that HSC potency linearly decreased with time when CB units were maintained at RT but remained stable when units were stored at 4°C pre-processing. This temperature-related difference was not observed with traditional assays, indicating that the test could be a complementary tool to characterize CB units in research and operational settings.

Axon guidance receptor ROBO3 modulates subtype identity and prognosis via AXL-associated inflammatory network in pancreatic cancer.

Metastatic pancreatic cancer (PDAC) has a poor clinical outcome with a 5-year survival rate below 3%. Recent transcriptome profiling of PDAC biopsies has identified 2 clinically distinct subtypes — the “basal-like” (BL) subtype with poor prognosis and therapy resistance compared with the less aggressive and drug-susceptible “classical” (CLA) subtype. However, the mechanistic events and environmental factors that promote the BL subtype identity are not very clear. Using preclinical models, patient-derived xenografts, and FACS-sorted PDAC patient biopsies, we report here that the axon guidance receptor, roundabout guidance receptor 3 (ROBO3), promotes the BL metastatic program via a potentially unique AXL/IL-6/phosphorylated STAT3 (p-STAT3) regulatory axis. RNA-Seq identified a ROBO3-mediated BL-specific gene program, while tyrosine kinase profiling revealed AXL as the key mediator of the p-STAT3 activation. CRISPR/dCas9-based ROBO3 silencing disrupted the AXL/p-STAT3 signaling axis, thereby halting metastasis and enhancing therapy sensitivity. Transcriptome analysis of resected patient tumors revealed that AXLhi neoplastic cells associated with the inflammatory stromal program. Combining AXL inhibitor and chemotherapy substantially restored a CLA phenotypic state and reduced disease aggressiveness. Thus, we conclude that a ROBO3-driven hierarchical network determines the inflammatory and prometastatic programs in a specific PDAC subtype.

Exploring the mechanism of berberine-mediated Tfh cell immunosuppression

BackgroundOur previous research revealed a novel function of berberine (BBR), a clinically relevant plant-derived alkaloid, as a suppressor of follicular T helper (Tfh) cell proliferation in secondary lymphoid organs of BBR-treated mice that underwent immunization for collagen-induced arthritis (CIA) in DBA1/J mice. Due to the importance of Tfh cell and B cell interactions in the generation of T cell-dependent humoral responses, the suppression of Tfh cell activity may have implications for the general safety of BBR as a prophylactic dietary supplement, and its potential use in antibody-driven autoimmune and hypersensitivity disorders. PurposeThis research aims to characterize BBR's impact on the activation, differentiation, and proliferation of Tfh cells by examining the expression of key extracellular signaling molecules, as well as the activity of intracellular signaling molecules involved in the Ca2+-calcineurin-NFAT pathway and STAT3 phosphorylation, following activation. Study designIn vitro experimental study using primary tissues. MethodsTo explore the direct effects of BBR on the proliferation and differentiation of Tfh cells, isolated naïve CD4+ T cells (>95% pure) were activated and differentiated into pre- Tfh cells in the presence or absence of BBR. The resulting Tfh cell populations and the expression of the key extracellular molecules CXCR5, ICOS, and PD-1 were measured. In addition, we examined the impact of BBR treatment on the activity of key intracellular signaling molecules involved in Tfh cell activation and differentiation following TCR ligation and/or CD28 signaling (p-ZAP-70, p-Lck, p-PLCγ1, NFATc1 and intracellular calcium, Ca2+, concentrations), as well as IL-6 signaling (p-STAT3). ResultsTreatment with BBR significantly reduced the expression of both CXCR5 (p < 0.01) and ICOS (p < 0.005), but not PD-1, and reduced the percentage of Tfh cells within the total CD4+ T cell population. BBR treatment also led to a reduction in intracellular Ca2+ flux, activation of p-STAT3, and IL-21 production. ConclusionOur observations provide insight into the mechanism of BBR-mediated Tfh cell suppression and suggest that BBR treatment can directly inhibit Tfh cell activity, perhaps through interfering with cytokine receptor or downstream signaling.

CHST15 gene germline mutation is associated with the development of familial myeloproliferative neoplasms and higher transformation risk

Herein, we describe the clinical and hematological features of three genetically related families predisposed to myeloproliferative neoplasms (MPNs). Using whole-exome sequencing, we identified a c.1367delG mutation(p.Arg456fs) in CHST15 (NM_001270764), a gene encoding a type II transmembraneglycoproteinthat acts as a sulfotransferase and participates in the biosynthesis of chondroitin sulfate E, in germline and somatic cells in familial MPN. CHST15defects caused an increased JAK2V617F allele burden and upregulated p-Stat3 activity,leading to an increase in the proliferative and prodifferentiation potential of transgenic HEL cells. We demonstrated that mutant CHST15 is able to coimmmunoprecipitate the JAK2 protein,suggesting the presence of a CHST15-JAK2-Stat3 signaling axis in familial MPN. Gene expression profiling showed that the FREM1, IFI27 and C4B_2 genes are overexpressed in familial MPN, suggesting the activation of an “inflammatory response-extracellular matrix-immune regulation” signaling network in the CHST15 mutation background.We thus concluded that CHST15 is a novel gene that predisposes to familial MPN and increases the probability of disease development or transformation.

Abstract LB218: A safe and highly potent anti-PD-1-IL-2c fusion that decouples efficacy and toxicity of IL-2 therapy

Abstract Interleukin 2 (IL-2) is a pivotal immune agonist for tumor immunotherapy that has produced impressive clinical efficacy in a number of cancer types. Nevertheless, its pleiotropic effect has led to prohibitory side effects and immune restraint. In contrast, the PD-1 blockade-based cancer immunotherapy has a good safety profile by targeting and sustaining the activity of tumor-antigen specific T cells within cancer tissues. To take full advantage of complementary antitumor activity of PD-1 monoclonal antibody (mAb) and IL-2 as well as supreme intratumoral T-cell-targeting property of PD-1, a bifunctional fusion protein composed of PD-1 mAb and IL-2 mutein (αPD-1-IL-2c) is designed. IL-2c is a chimeric molecule that contains a fragment from IL-15 and does not bind to IL-2 receptor alpha (IL-2Rα). αPD-1-IL-2c stimulated greater pSTAT5 activation and proliferation in PD-1+ T cells than PD-1- T cells. αPD-1-IL-2c also induced a much stronger anti-tumor immune response compared to PD-1 mAb, IL-2c, or PD-1 mAb in combination with IL-2c in multiple syngeneic models such as B16F10, CT26, and MC38. In CT26 and MC38 models, αPD-1-IL-2c achieved complete response starting from 0.3 mg/kg dosing. In B16F10 model, αPD-1-IL-2c showed greater than 70% tumor growth inhibition (TGI). Global gene expression profiling studies showed that PD-1-IL-2c treatment significantly elevated expression levels of Cd3d, Cd3e, Cd8a, Il2rα, Cxcr3, Cxcr6, Zap70, Lck, and Pdcd1 in tumor tissues compared to treatment with PD-1 mAbs or IL-2c, indicating a specific expansion and activation of T cell in the tumor microenvironment (TME). The safety profile of αPD-1-IL-2c was assessed and compared to WT IL-2 and a leading “No-α” αPD-1-IL-2 fusion protein (αPD-1-IL-2x). WT IL-2 and αPD-1-IL-2x induced significant body weight loss and severe splenomegaly when dosed at 1.25 mg/kg. In contrast, αPD-1-IL-2c dosed at 10 mg/kg did not cause appreciable body weight loss and only led to minimal splenomegaly. In summary, we have developed a safe and highly potent αPD-1-IL-2 mutein that achieves full PD-1 blockade and TME-specific T cell activation and expansion without appreciable toxicity. Citation Format: Fan Ye, Jianing Huang, Zoey Huang, Sandra Chen, Eric Liao, Ella Li, Allison Quach, Jenny Jiang, Hanna Lin, Michael Hua, Savannah Yung, Lili Cheng, Ziyang Zhong. A safe and highly potent anti-PD-1-IL-2c fusion that decouples efficacy and toxicity of IL-2 therapy [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 LB218.

Nifuroxazide in combination with CpG ODN exerts greater efficacy against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignant tumour in China that remains a major challenge to the medical community, and effective treatment is urgently needed. Due to complex tumorigenesis, monotherapy shows poor therapeutic effects, and combined treatment becomes a necessary option. YW002, a CpG ODN-containing sequence, has been proven to enhance antitumor effects in tumour-bearing mouse models. Moreover, as a broad-spectrum antimicrobial drug, nifuroxazide exhibited an anti-HCC effect through activation of p-Stat3. Here, we tested the effect of nifuroxazide on HCC in vitro and then explored the therapeutic effect of combined nifuroxazide and CpG ODN on HCC in vivo. Nifuroxazide inhibited proliferation, induced apoptosis and suppressed migration and invasion in HepG2 cells in vitro. The combination therapy using nifuroxazide and CpG ODN significantly suppressed the growth of tumours in tumour-bearing mice with few side effects and achieved better therapeutic effects on HCC than monotherapy. Moreover, combined nifuroxazide and CpG ODN therapy significantly induced apoptosis, enhanced the infiltration of CD4+ and CD8+ T lymphocytes and macrophages in tumour tissue, and increased the ratio of CD4+ and CD8+ T lymphocytes in the spleens of tumour-bearing mice. The introduction of this combination therapy combining nifuroxazide and CpG ODN provided a new strategy for HCC treatment.

SAHA Alleviates Diarrhea-Predominant Irritable Bowel Syndrome Through Regulation of the p-STAT3/SERT/5-HT Signaling Pathway.

ObjectiveIrritable bowel syndrome (IBS) is characterized by abdominal pain, bloating, and stool irregularity. However, its pathophysiological mechanisms, which trigger intestinal motility disorders and diarrhea leading to diarrhea-predominant IBS (D-IBS), remain largely unknown.MethodsIn the present study, we established a D-IBS rat model by mother–infant separation combined with restraint stress. Then we exposed the modelled rats to suberoylanilide hydroxamic acid (SAHA) treatment, followed by determination of their visceral sensitivity. Toluidine blue staining served to reveal the effects of SAHA treatment on mast cells of D-IBS model rats. Then we measured the expression of serotonin (5-hydroxytryptamine; 5-HT) and its receptors by ELISA.ResultsConstruction of short hairpin RNA (sh)-serotonin transporter (SERT) lentivirus vectors verified the regulation of the 5-HT signaling pathway by phosphorylated (p)-STAT/SERT. SAHA treatment of D-IBS model rats reduced the fecal water content, electromyography integral change rate, abdominal withdrawal reflex score, and number of mast cells, as well as the expression of 5-HT type 3A (5-HT3AR), 3B receptor (5-HT3BR), and 4 receptor (5-HT4R) receptors. The treatment also elevated the expression of signal transducer and activator for transcription 3 (STAT3) and SERT. Activation of p-STAT3 may reverse the inhibitory effect of SAHA on the elevated visceral sensitivity of D-IBS model rats. Moreover, SAHA promoted the transcription of SERT through repression of the p-STAT3/5-HT signaling, thereby inhibiting the visceral sensitivity of D-IBS model rats.ConclusionThis study highlights that SAHA treatment can alleviate D-IBS through regulation of the p-STAT3/SERT/5-HT signaling pathway.

Agnuside mitigates OVA-LPS induced perturbed lung homeostasis via modulating inflammatory, autophagy, apoptosis-fibrosis response and myeloid lineages in mice model of allergic asthma

Attributes of agnuside, a nontoxic, iridoid glycoside have been advocated for inflammatory disorders. However, information on its efficacy in alleviating allergic asthma largely remain ambiguous and yet to be deciphered. Present study aimed to assess efficacy of agnuside in targeting vicious circle of oxi-inflammation, autophagy and fibrosis, together with investigating its underlying molecular mechanism during OVA-LPS induced allergic asthma. Results revealed that agnuside showed prophylactic effect in assuaging asthmatic lung architecture impairment (p ≤ 0.01) as indicated by suppression of inflammatory cell infiltration, congestion, fibrosis, airway remodeling and alveolar collapse in OVA-LPS sensitized group. Decreased expression level (p ≤ 0.05) of allergic inflammatory mediators such as IgE, Th1/Th2, IL-4/IFN-γ, IL-4/IL-10, chemokines, endopeptidases and TGF-β, Smad2/4, Caspase9/3, connexin 43/50 observed in agnuside treatments. Analysis of redox molecular signaling cascade and autophagic proteins revealed concurrent upregulation in p-NF-κB, p-PI3K, p-Akt, p-p38, p-Stat3 activation, GATA3, LC3B expression and reduction in Bcl2/Bax, Beclin1 and p62 expression in sensitized mice (p ≤ 0.05) which were intensely counteracted by administration of agnuside. Suppression in myeloid cells activation and augmentation (p ≤ 0.001) of Tregs established modulatory attribute of agnuside for innate and adaptive immune response during allergic asthma. Collectively, these outcomes confer prophylactic attribute of agnuside and signify it as promising strategy to thwart allergic asthma.

The role of α5-nicotinic acetylcholine receptor/NLRP3 signaling pathway in lung adenocarcinoma cell proliferation and migration

α5-nicotinic acetylcholine receptor (α5-nAChR) is involved in tobacco smoking-induced lung carcinogenesis. Increasing evidence has highlighted the importance of inflammation in lung cancer and a strong relationship between smoking and the NLR family pyrin domain containing protein 3 (NLRP3) inflammasome. However, it is unclear whether an inflammation-related effect of α5-nAChR contributes to cigarette smoking-related lung cancer. Here, we identified a functional link between α5-nAChR and NLRP3 inflammasome activation in lung adenocarcinoma (LUAD). The expression of α5-nAChR was correlated with the expression of NLRP3 via STAT3 in LUAD tissues. In vitro, nicotine increased the levels of α5-nAChR, p-STAT3, and NLRP3 inflammasome expression, accompanied by the expression of caspase-1, IL-1β and IL-18. Nicotine-induced activation of p-STAT3 and NLRP3 inflammasome signaling were inhibited by the silencing of α5-nAChR. STAT3 binds to the NLRP3 promoter and α5-nAChR mediates NLRP3 expression via STAT3. Functionally, the combination of nicotine and LPS/ATP could significantly enhance cell proliferation and migration compared to nicotine or LPS/ATP alone. Furthermore, the functional link between α5-nAChR and NLRP3 was confirmed in chicken embryo chorioallantoic membrane (CAM) and mouse xenograft models. Together, these findings reveal a novel nicotine-mediated signaling pathway: nicotine promotes lung cell proliferation and migration via the α5-nAChR/STAT3/NLRP3 axis in lung cancer.

Myeloid Diagnostic and Prognostic Markers of Immune Suppression in the Blood of Glioma Patients

BackgroundAlthough gliomas are confined to the central nervous system, their negative influence over the immune system extends to peripheral circulation. The immune suppression exerted by myeloid cells can affect both response to therapy and disease outcome. We analyzed the expansion of several myeloid parameters in the blood of low- and high-grade gliomas and assessed their relevance as biomarkers of disease and clinical outcome.MethodsPeripheral blood was obtained from 134 low- and high-grade glioma patients. CD14+, CD14+/p-STAT3+, CD14+/PD-L1+, CD15+ cells and four myeloid-derived suppressor cell (MDSC) subsets, were evaluated by flow cytometry. Arginase-1 (ARG1) quantity and activity was determined in the plasma. Multivariable logistic regression model was used to obtain a diagnostic score to discriminate glioma patients from healthy controls and between each glioma grade. A glioblastoma prognostic model was determined by multiple Cox regression using clinical and myeloid parameters.ResultsChanges in myeloid parameters associated with immune suppression allowed to define a diagnostic score calculating the risk of being a glioma patient. The same parameters, together with age, permit to calculate the risk score in differentiating each glioma grade. A prognostic model for glioblastoma patients stemmed out from a Cox multiple analysis, highlighting the role of MDSC, p-STAT3, and ARG1 activity together with clinical parameters in predicting patient’s outcome.ConclusionsThis work emphasizes the role of systemic immune suppression carried out by myeloid cells in gliomas. The identification of biomarkers associated with immune landscape, diagnosis, and outcome of glioblastoma patients lays the ground for their clinical use.

Keratin 17 as a Marker of UVB-Induced Stress in Human Epidermis and Modulation by Vitis vinifera Extract

Human epidermis responds to ultraviolet (UV)B-induced damage by tolerating it, restoring it, or undergoing programmed cell death when the damage is massive. Recently, compounds rich in polyphenols, such as Vitis vinifera L. leaf extract (VVLe), have attracted a lot of interest for skin protection. We investigated the effect of VVLe pre-treatment (1 h) in a 2D model of HaCaT cells and in 3D organotypic cultures of normal human skin exposed to a single UVB dose to study the immediate specific events 1 h and the response orchestrated in the epidermal layer 24 h after irradiation, respectively. In both models, transmission electron microscopy analysis was carried out. The expression of the inducible keratin K17, the activation of both pSTAT3 and Nuclear Factor (NF)-κB signalling pathways, and the epidermal distribution of Toll-Like Receptor (TLR) 4 were assessed by immunofluorescence in the 2D and 3D model. In 3D organotypic cultures, thanks to the preservation of a multi-layered structure, the epidermal distribution of the differentiation biomarkers K10 and K14 as well as of K16 was analysed by immunofluorescence, while the release of interleukin (IL)-8 was evaluated by ELISA. In skin bioptic fragments, cytotoxicity and genotoxicity were investigated by LDH assay and Alkaline Comet assay, respectively, and then compared to cell proliferation. The epidermal distribution of the histone γ-H2AX, indicating the fragmented DNA, was analysed by immunofluorescence. In both experimental models, VVLe tuned UVB-induced K17 expression to a different extent in HaCaT cells and in the skin. In HaCaT cells, pSTAT3 activation was induced by UVB and reverted by VVLe pre-treatment. TLR4 expression was triggered by UVB in both models, but VVLe pre-treatment abolished this event only in HaCaT cells. NF-κB immunostaining increased both in the nucleus and in the cytoplasm only in HaCaT cells after UVB irradiation. In all irradiated skin samples, VVLe pre-treatment was not able to revert the inhibition of epidermal proliferation, K16 expression, and IL-8 secretion. The effectiveness of VVLe in contrasting the irradiation-induced genotoxicity still remains unclear. In conclusion, our study clearly shows that K17 is a robust marker induced in keratinocytes upon UVB stimulation and that this event can be reverted by a pre-treatment with VVLe. On the whole, these observations represent a novelty in the scenario of the complex relationships between the effects exerted by UVB rays on human skin and significantly improve the knowledge regarding the modulation of the early epidermal response induced by a single exposure to UVB in the presence of VVLe.

Receptor Tyrosine Kinase Inhibitor Sunitinib as Novel Immunotherapy to Inhibit Myeloid-Derived Suppressor Cells for Treatment of Endometriosis.

Endometriosis is a common, benign, and hormone-dependent gynaecological disorder that displays altered immunoinflammatory profiles. Myeloid-derived suppressor cells (MDSCs) suppressed immunosurveillance in endometriosis in human and mouse model. Receptor tyrosine kinase inhibitor Sunitinib can induce MDSC apoptosis and suppress the progression of cancer. However, the effects of Sunitinib on MDSCs in endometriosis and the underlying mechanism are not clear. In this study, we employed an animal study of the endometriosis model in mice for treatment of Sunitinib. After syngeneic endometrium transplantation and treatment, endometriotic lesion volume, weight, and histology were compared. Peritoneal fluid, peripheral blood, and bone marrow MDSC subsets and their molecular signaling were monitored by flow cytometry. Peritoneal cytokines were assayed by ELISA. The gene expression profiles of isolated CD11b+Ly6G+Ly6Clo cells were studied by RNA sequencing. We found that Sunitinib significantly decreased the endometriotic lesion size and weight after 1 and 3 weeks, and decreased p-STAT3 activation in MDSCs after 1 week of treatment. In the first week, Sunitinib specifically increased the G-MDSC population in peritoneal fluid but the isolated CD11b+Ly6G+Ly6Clo MDSCs after Sunitinib treatment were presented as mature polynuclear MDSCs, while the control group had immature mononuclear MDSCs. Importantly, we found Sunitinib differentially suppressed gene expressions of immunosuppressive function and differentiation in peritoneal G-MDSCs. Apelin signaling pathway associated genes and inflammation related genes were upregulated, and amino acid metabolism regulator genes were downregulated in bone marrow G-MDSCs. For endometriotic lesions, the PPARG gene governing glucose metabolism and fatty acid storage, which is important for the development of endometriosis was upregulated. In conclusion, Sunitinib inhibited endometriotic lesions, by promoting peritoneal fluid MDSCs maturation and inhibiting the immunosuppressive function. These findings suggest that Sunitinib changed the immune microenvironment and inhibited the development of endometriosis, which has potential therapeutic effects as novel immunotherapy to promote MDSCs maturation, differentiation, and metabolism for the treatment of endometriosis.

Transneuronal delivery of designer cytokines: perspectives for spinal cord injury.

Transneuronal delivery of designer cytokines: perspectives for spinal cord injury.

Abstract 1428: PARP inhibitor resensitizes TKI-resistant AML to TKI

Abstract Internal tandem duplications within the juxtamembrane domain of fms-like tyrosine kinase 3 (FLT3-ITD) are present in approximately 25% of patients with acute myeloid leukemia (AML) and is an independent predictor of poor prognosis. FLT3-ITD is a constitutively active form of the receptor and aberrantly signals through signal transducer and activator of transcription (STAT) 5 which feeds-back to stabilize FLT3 through the downstream effector, Pim-1 kinase. FLT3-specific tyrosine kinase inhibitors (TKI) have clinical effects in FLT3-ITD AML but responses are limited due to the development of resistance through various means, including point mutations in the FLT3 tyrosine kinase domain commonly at D835 in the activation loop and F691 in the gate-keeper residue. Novel therapeutic strategies are therefore required for overcoming TKI-resistance. Poly (ADP-ribose) polymerase (PARP) 1 functions by poly-ADP-ribosylating (PAR) itself and other proteins primarily to catalyze DNA repair, however, PARP can also regulate the activity and function of proteins involved in other various processes. Notably, PARP inhibitors (PARPi) are novel cancer therapeutics that induce synthetic lethality in cancers with BRCA mutations. Recent studies also show that concurrent treatment of PARPi and TKI can effectively induce synthetic lethality in BRCA-proficient TKI-sensitive FLT3-ITD AML. However, the effects of PARPi in TKI-resistant disease has yet to be explored. We previously reported elevated reactive oxygen species (ROS) in FLT3-ITD AML leading to upregulated PARP1 and we now show that, compared to parental TKI-sensitive Molm14 cells, D835Y and F691L point-mutated TKI-resistant forms have significantly increased ROS production, and subsequently increased DNA damage and PARP1 protein expression. Interestingly, TKI-resistant cells also have elevated phospho-STAT5 (pSTAT5) and subsequent CRISPR-Cas9 knockout of PARP1 leads to reduction in pSTAT5 as well as the downstream targets, Pim-1 and FLT3. Significantly, STAT5 protein was found to immunoprecipitate with PAR and PARP1, suggesting for the first time that PARP1 may play a direct role in regulating STAT5. Finally, we have found that low doses (5-50nM) of the potent PARPi, Talazoparib (Tal), in combination with low dose (10nM) of the TKIs, Quizartinib (Quiz) or Gilteritinib (Gilt), is synergistically lethal in the otherwise TKI-resistant cells. Additionally, sequential treatment of TKI-resistant cells with Tal (72hr) prior to treatment with Quiz (72hr) or Gilt (72hr) was still synergistic whereas the reverse is not. This suggests a novel model whereby Tal may resensitize cells to TKI by decreasing PARP1 effects on pSTAT5 activity which feeds back to reduce FLT3 receptor activation. Therefore, this combination has potential for treatment of TKI-resistant AML and studies are underway to translate these findings with the intent of developing an effective therapy for patients with this disease. Citation Format: Anna J. Dellomo, Rena G. Lapidus, Mariusz Karbowski, Maria R. Baer, Tami J. Kingsbury, Feyruz V. Rassool. PARP inhibitor resensitizes TKI-resistant AML to TKI [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1428.

Identification of Functional Determinants of Response and Resistance to CD19 Chimeric Antigen Receptor (CAR) T-Cell Therapy of Chronic Lymphocytic Leukemia

The adoptive transfer of autologous T cells genetically modified to express a chimeric antigen receptor (CAR) targeting CD19 has shown remarkable activity for patients with B cell malignancies. Using a second- generation CAR signaling through 4-1BB/CD3ζ, (CTL019), over 90% of patients with relapsed or refractory (R/R) acute lymphoblastic leukemia (ALL) will achieve complete remission (Maude, S.L. et. al. New England Journal of Medicine, 2014). Similar therapy can induce long-term remissions for R/R chronic lymphocytic leukemia (CLL), but only in a subset of patients (Porter, D.L. et. al. Science Transl. Medicine, 2015). The ability to identify individuals most likely to respond will have a dramatic impact on patient selection and provide critical information that may allow immune modification to enhance responses using this approach. We here present updated analyses and functional validation of our previously reported biomarker profiles of CTL019 cells in CLL (Fraietta, J.A. et. al., Blood, 2016). Retrospective samples of clinically manufactured CAR T cells from forty-one patients with advanced, heavily pre-treated and high-risk CLL were evaluated for functional determinants of potency. Transcriptomic analysis of CTL019 cells from subjects who had complete responses (CR) to this therapy revealed enrichment in early memory T cells and IL-6/STAT3 gene signatures, while T cells from non-responding (NR) patients were enriched in genes belonging to known pathways of terminal differentiation, exhaustion, apoptosis and glycolysis. Accordingly, CAR-stimulated T cells from NR relative to CR patents demonstrated an increased uptake of a glucose analog; inhibition of glycolysis using 2-deoxy-D-glucose resulted in the generation of early memory CAR T cells in culture. Furthermore, CTL019 cells that were highly functional in CLL patients had increased levels of phosphorylated STAT3 (pSTAT3) upon activation compared to CAR T cells from NR patients with poor anti-tumor activity. These data were concordant with the highly significant direct correlation between serum IL-6 and the degree of CTL019 proliferative capacity in patients. Increasing pSTAT3 activity by addition of exogenous IL-6 to culture media elevated the absolute numbers of CAR T cells following repeated stimulation with CD19-expressing tumor targets, while pSTAT3 inhibition diminished CTL019 cell growth.Single-cell proteomic analysis of CAR-stimulated CTL019 cells from CLL patients revealed marked heterogeneity in cytokine secretions and enhanced polyfunctional strength in CAR T cells from responding over non-responding patients. There were multiple contributors to CTL019 cell polyfunctional strength, including granzyme B, MIP-1α, IFNg, TNFα, IL-5, IL-8, MIP-1β and perforin. We next performed deep immunophenotyping on the above pre-infusion CAR T cells and, through unbiased computational analysis of the flow cytometry data, defined a single subset (CD8+CD27-PD1-) that segregated CRs from NRs. Importantly, we noted a highly significant association between the likelihood of having a response to CTL019 therapy and the infusion of CTL019 products containing a high dose of CD8+PD1-CD27+ CAR T cells. To confirm that this cell population drives the response to CTL019 therapy, we depleted it from CR patient CTL019 cells and observed loss of tumor control and decreased survival in leukemia-bearing NOD scid gamma (NSG) mice compared to animals treated with subject-matched unmanipulated cellular products. These findings, coupled with our previous results, reveal a functionally relevant T lymphocyte population that can serve as a novel predictive biomarker and a framework for future mechanistic dissection to enhance the efficacy of CAR T cell therapies. DisclosuresFraietta:Novartis: Patents & Royalties: patents, Research Funding. Lacey:Novartis: Research Funding; Genentech: Honoraria. Orlando:Novartis: Employment. Pruteanu:Novartis Pharmaceuticals Corporation: Employment. OConnor:Novartis: Research Funding. Chen:Novartis: Research Funding. Davis:Novartis: Research Funding. Young:Novartis: Research Funding. Levine:Brammer Bio: Consultancy; Tmunity Therapeutics: Equity Ownership, Research Funding; GE Healthcare: Consultancy; Novartis Pharmaceuticals Corporation: Patents & Royalties, Research Funding. Siegel:Novartis: Research Funding. Zhou:IsoPlexis: Employment, Equity Ownership. Paczkowski:IsoPlexis: Employment, Equity Ownership. Mackay:IsoPlexis: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Speakers Bureau. Brogdon:Novartis: Employment. Bitter:Novartis: Employment. Porter:Incyte: Honoraria; Novartis: Honoraria, Patents & Royalties, Research Funding; Servier: Honoraria, Other: Travel reimbursement; Genentech/Roche: Employment, Other: Family member employment, stock ownship - family member; Immunovative Therapies: Other: Member DSMB. June:Tmunity Therapeutics: Equity Ownership, Research Funding; WIRB/Copernicus Group: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celldex: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immune Design: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Novartis: Patents & Royalties, Research Funding. Melenhorst:Novartis: Research Funding.