IL-2R Pathway Research Articles

Immunosuppressive effects of triptolide via interleukin-2/receptor signaling

Background Triptolide (TP) has been confirmed to possess many beneficial functions including anti-inflammation and immunosuppression. Objective The present study aimed to explore the potential involvement of IL-2/IL-2R pathway in the immunosuppressive activities of TP. Methods Cultured CTLL-2 cells were utilized to evaluate the potential benefits of TP. Then cell viability was determined by CCK-8 assay, IFN-γ level by ELISA assay, Annexin V-FITC/PI double-staining and CD25 expression by flow cytometry, and protein expression by western blotting. Additionally, rhIL-2–driven lymphocytes following ConA activation were investigated. The interactions of TP with IL-2 and IL-2Rα were investigated by binding assays and molecular dynamics simulations. Results TP treatment attenuated IFN-γ level and cell viability in both rhIL-2–induced CTLL-2 cells and rhIL-2–driven splenic lymphocytes. TP treatment increased cellular apoptosis/necrosis and cleaved PARP-1 level, while suppressed c-Myc level in rhIL-2–induced CTLL-2 cells. Additionally, TP treatment reduced CD25 expression on CTLL-2 cell surface. Notably, the phosphorylation protein levels in IL-2R signaling pathways were inhibited by TP exposure prior to rhIL-2 stimulation. SPR and BLI assays verified TP that directly bound to rhIL-2 and rmIL-2Rα, respectively. Molecular simulations suggested that TP bound at the interface of IL-2 and IL-2Rα near the hydrophobic patch composed of F62, L92 on IL-2 and L23, I46, V139 on IL-2Rα, resulting in decreased binding free energy between IL-2 and IL-2Rα. Conclusions These findings collectively emphasized that TP interfered IL-2/IL-2Rα interactions, down-regulated IL-2Rα expression, and inhibited IL-2R signaling pathways activation, thereby leading to the immune cells being desensitized to rhIL-2 and exhibiting immunosuppressive properties.

APOE ε4-associated downregulation of the IL-7/IL-7R pathway in effector memory T cells: Implications for Alzheimer's disease.

The apolipoprotein E (APOE) ε4 allele exerts a significant influence on peripheral inflammation and neuroinflammation, yet the underlying mechanisms remain elusive. The present study enrolled 54 patients diagnosed with late-onset Alzheimer's disease (AD; including 28 APOE ε4 carriers and 26 non-carriers). Plasma inflammatory cytokine concentration was assessed, alongside bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) analysis of peripheral blood mononuclear cells (PBMCs). Plasma tumor necrosis factor α, interferon γ, and interleukin (IL)-33 levels increased in the APOE ε4 carriers but IL-7 expression notably decreased. A negative correlation was observed between plasma IL-7 level and the hippocampal atrophy degree. Additionally, the expression of IL-7R and CD28 also decreased in PBMCs of APOE ε4 carriers. ScRNA-seq data results indicated that the changes were mainly related to the CD4+ Tem (effector memory) and CD8+ Tem T cells. These findings shed light on the role of the downregulated IL-7/IL-7R pathway associated with the APOE ε4 allele in modulating neuroinflammation and hippocampal atrophy. The apolipoprotein E (APOE) ε4 allele decreases plasma interleukin (IL)-7 and aggravates hippocampal atrophy in Alzheimer's disease. Plasma IL-7 level is negatively associated with the degree of hippocampal atrophy. The expression of IL-7R signaling decreased in peripheral blood mononuclear cells of APOE ε4 carriers Dysregulation of the IL-7/IL-7R signal pathways enriches T cells.

Single-cell RNA sequencing reveals Immune Education promotes T cell survival in mice subjected to the cecal ligation and puncture sepsis model.

Individual T cell responses vary significantly based on the microenvironment present at the time of immune response and on prior induced T cell memory. While the cecal ligation and puncture (CLP) model is the most commonly used murine sepsis model, the contribution of diverse T cell responses has not been explored. We defined T cell subset responses to CLP using single-cell RNA sequencing and examined the effects of prior induced T cell memory (Immune Education) on these responses. We hypothesized that Immune Education prior to CLP would alter T cell responses at the single cell level at a single, early post-CLP time point. Splenic T cells were isolated from C57BL/6 mice. Four cohorts were studied: Control, Immune-Educated, CLP, and Immune-Educated CLP. At age 8 weeks, Immune-Educated and Immune-Educated CLP mice received anti-CD3ϵ antibody; Control and CLP mice were administered an isotype control. CLP (two punctures with a 22-gauge needle) was performed at 12-13 weeks of life. Mice were sacrificed at baseline or 24-hours post-CLP. Unsupervised clustering of the transcriptome library identified six distinct T cell subsets: quiescent naïve CD4+, primed naïve CD4+, memory CD4+, naïve CD8+, activated CD8+, and CD8+ cytotoxic T cell subsets. T cell subset specific gene set enrichment analysis and Hurdle analysis for differentially expressed genes (DEGs) were performed. T cell responses to CLP were not uniform - subsets of activated and suppressed T cells were identified. Immune Education augmented specific T cell subsets and led to genomic signatures favoring T cell survival in unoperated and CLP mice. Additionally, the combination of Immune Education and CLP effected the expression of genes related to T cell activity in ways that differed from CLP alone. Validating our finding that IL7R pathway markers were upregulated in Immune-Educated CLP mice, we found that Immune Education increased T cell surface IL7R expression in post-CLP mice. Immune Education enhanced the expression of genes associated with T cell survival in unoperated and CLP mice. Induction of memory T cell compartments via Immune Education combined with CLP may increase the model's concordance to human sepsis.

High-content multimodal analysis supports the IL-7/IL-7 receptor axis as a relevant therapeutic target in primary Sjögren's syndrome

ObjectiveWhile the involvement of IL-7/IL-7R axis in pSS has been described in relation to T cells, little is known about the contribution of this pathway in relationship with other immune cells, and its implication in autoimmunity. Using high-content multiomics data, we aimed at characterizing IL-7R expressing cells and the involvement of IL-7/IL-7R pathway in pSS pathophysiology. MethodsAn IL-7 signature established using RNA-sequencing of human PBMCs incubated with IL-7 was applied to 304 pSS patients, and on RNA-Seq datasets from tissue biopsies. High-content immunophenotyping using flow and imaging mass cytometry was developed to characterize peripheral and in situ IL-7R expression. ResultsWe identified a blood 4-gene IL-7 module (IKZF4, KIAA0040, PGAP1 and SOS1) associated with anti-SSA/Ro positiveness in patients as well as disease activity, and a tissue 5-gene IL-7 module (IL7R, PCED1B, TNFSF8, ADAM19, MYBL1) associated with infiltration severity. We confirmed expression of IL-7R on T cells subsets, and further observed upregulation of IL-7R on double-negative (DN) B cells, and especially DN2 B cells. IL-7R expression was increased in pSS compared to sicca patients with variations seen according to the degree of infiltration. When expressed, IL-7R was mainly found on epithelial cells, CD4+ and CD8+ T cells, switched memory B cells, DN B cells and M1 macrophages. ConclusionThis exhaustive characterization of the IL-7/IL-7R pathway in pSS pathophysiology established that two IL-7 gene modules discriminate pSS patients with a high IL-7 axis involvement. Their use could guide the implementation of an anti-IL-7R targeted therapy in a precision medicine approach.

JAK2V617F Activates IL-10R Signalling Potentially through Transactivation of JAK1

Classical myeloproliferative neoplasms (MPNs) arise from somatic mutations in haematopoietic stem cells (HSCs) that lead to unregulated proliferation of mature myeloid cells. The most common mutation associated with MPNs is JAK2 V617F, this causes constitutive JAK-STAT signalling leading to excessive production of mature myeloid cells. In humans, for MPN to arise, a JAK2 V617F HSC must have a selective advantage over WT HSC. However, in mouse MPN models Jak2 V617F HSCs do not display an overt selective advantage. This suggests that unique selective pressures may be present among those predisposed to acquire MPN that allow for the emergence of Jak2 V617F clones. We have identified defects in the IL-10R signalling pathway among MPN patients, with evidence that this defect is an intrinsic not acquired abnormality. In mice, we found that the blockade of IL-10R extends the cycling of WT but not Jak2 V617FHSC in response to inflammatory stimuli and hastens proliferation-induced WT HSC exhaustion. We hypothesized that IL-10R blockade may create an environment that affords Jak2 V617F HSC a selective advantage, indeed we found that IL-10R blocking antibody allowed Jak2 V617F cells to outcompete WT cells in mouse transplant experiments. From these mouse data, we hypothesized that Jak2 V617Fenhances IL-10R signalling. To test this hypothesis, we created Ba/F3 cell lines co-expressing IL-10Rα and Jak2 V617F. We found that Jak2 V617F enhances growth at limiting concentrations of IL-10. We also found that cytokine-independent IL-10Rα Jak2 V617F clones (but never IL-10Rα Jak2 WTor IL-10Rα cells) emerge at day 8-10 in culture after withdrawal of cytokines. We performed a limiting dilution assay to pinpoint the proportion of IL-10R Jak2 V617F cells capable of surviving IL-3 withdrawal. One in 126 IL-10Rα Jak2 V617F cells has transforming ability, whereas 1 in 1.4 MPL Jak2 V617F has transforming ability. Together, these data support our hypothesis that Jak2 V617F enhances IL-10R signalling and can activate IL-10Rα, however with weaker transformation potential compared to Jak2V617F's activation of MPL signalling. JAK2 canonically does not participate in the IL-10R pathway. It has been previously shown that JAK1 can transactivate JAK2 when JAK2 V617F cells are under the stress of persistent JAK2 inhibitor exposure, and this is the purported mechanism of JAK inhibitor resistance among MPN patients. We hypothesized that JAK2 V617F can transactivate JAK1, leading to the activation of IL-10R. The same transfected BaF3 cells aforementioned were serum starved for 4 hours and stimulated with mIL-10 for 15 minutes to induce signalling. By way of Western Blot analysis, cytokine-independent Jak2 V617F IL-10Rα Ba/F3 cells showed constitutive activation of phosphorylated JAK1 and JAK2 as well as STAT3 and STAT5, consistent with transactivation. Studies to demonstrate direct interactions between JAK2 V617F and JAK1 are currently ongoing.

Abstract LB338: A novel class of T cell-activators targeting germline encoded TCRβ chains promotes antitumor activity in PD1-refractory models through expansion of a clonally enriched effector memory T cell subset

Abstract Background: Here we describe a new class of selective T cell activator molecule that combines antibody targeting of the variable (V) β regions of the T cell receptor (TCR) with a costimulatory cytokine. STAR0602, a molecule that selectively targets T cells expressing Vβ6 and Vβ10 TCRs and delivers IL-2R co-stimulation, activates and expands human Vβ6 and Vβ10 T cells that are enriched in tumor infiltrating lymphocytes (TIL) relative to other Vβ subsets. Using this molecular design, STAR0602 and molecules targeting other Vβ T cell subsets simultaneously engage a novel, non-clonal mode of TCR activation with cytokine co-stimulation. Methods: The effects of STAR0602 on activation and expansion of primary human T cells were assessed in vitro by flow cytometry, homogeneous time-resolved fluorescence, TCRseq, and NanoString. Several murine surrogate molecules targeting different Vβ T cell subsets with a range of baseline frequencies were tested in murine syngeneic tumor models. Tumors were excised for phenotyping of TILs including tetramer staining of antigen specific T cells using flow cytometry, and scRNAseq/TCRseq. Results: In vitro, STAR0602 induced TCR signaling and IL-2R pathway activation in human T cells that preceded expansion of Vβ6/Vβ10 T cells that acquired an atypical central memory T cell (TCM) phenotype. Across PD1-refractory syngeneic murine tumor models, monotherapy with fusion molecules targeting different Vβ TCR and delivering IL-2R co-stimulation induced potent anti-tumor activity that was associated with expansion and accumulation of targeted Vβ T cell subsets in blood and tumors. In vivo anti-tumor activity was dependent on the accumulation of effector memory T or TCM Vβ T cells expressing a novel effector gene signature. Additional analysis of TILs showed increased clonality in de novo expanded Vβ T cells compared to controls in addition to increased numbers of tumor-specific T cells. Conclusions: To our knowledge, the use of therapeutic antibodies to selectively target and expand Vβ T cell subsets and thereby modulate the germline TCR repertoire for therapeutic benefit is novel. Here we show that STAR0602 selectively binds and activates human Vβ6/Vβ10 T cells and promotes a novel TCM phenotype. Murine surrogate molecules targeting different Vβ T cell subsets demonstrated potent and durable single-agent anti-tumor activity even when targeting low frequency Vβ subsets. These expanded Vβ T cells appear to drive enhanced anti-tumor activity due to their increased effector potentials, novel memory phenotype, and a striking enrichment in clonal diversity. In summary, STAR0602 and similar Vβ TCR-targeting constructs have the potential to remodel the adaptive immune response to solid tumors that are refractory to anti-PD1 therapy. A Phase 1/2 clinical trial of STAR0602 is ongoing in patients with advanced metastatic cancers. Citation Format: Jacques Moisan, Madan Katraggada, Jonathan Hsu, Jessica Lowry, Wei Huang, Jian Tang, Roya Servattalab, Gurkan Guntas, Raj Chopra, Zhen Su, Andrew Bayliffe. A novel class of T cell-activators targeting germline encoded TCRβ chains promotes antitumor activity in PD1-refractory models through expansion of a clonally enriched effector memory T cell subset [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB338.

P721 Treatment of Ulcerative Colitis with OSE-127 (lusvertikimab), a Strict IL-7Rα Antagonist, Non-Cytotoxic Monoclonal Antibody

Abstract Background Key transcripts of the IL-7R pathway were shown to accumulate in inflamed colon tissues of severe IBD patients not responding to conventional or biologics therapies. Furthermore, high expression of both IL7R and IL-7R signaling signature in the colon before treatment is strongly associated with non-responsiveness to anti-TNF therapy. We have designed a humanized monoclonal antibody targeting the IL-7Rα chain, named OSE-127 (lusvertikimab), which displays strict antagonist activity without cytotoxicity nor internalizing properties. In an ex vivo culture system using colon biopsies from UC patients, OSE-127 altered synthesis of interferon γ by Teff. In addition, IL-7R blockade by OSE-127 in humanized mouse models reduced human T cell homing to the gut and colonic inflammation (Belarif L et al, 2019). Methods A first-in-human, phase I, randomized, double-blind, placebo-controlled, single-center study was carried out to determine the safety, pharmacokinetics and pharmacodynamics of OSE-127 administration. Results Sixty-three healthy subjects were randomly assigned to OSE-127 or placebo with 45 of them exposed to the active product in 9 groups: 6 single ascending dose groups with intravenous (IV) administration (0.002-10 mg/kg), 1 subcutaneous treatment group (1 mg/kg) and 2 double IV infusion groups (6 or 10 mg/kg). OSE-127 was well tolerated, with no evidence of cytokine-release syndrome and no significant alteration of blood lymphocyte counts or subset populations. OSE-127’s pharmacokinetic half-life after a single dose increased from 4.6 days (1mg/kg) to 11.7 days (10 mg/kg) and, after a second dose, from 12.5 days (6 mg/kg) to 16.25 days (10 mg/kg). Receptor occupancy was ≥ 95% at doses ≥ 0.02 mg/kg and this saturation level was maintained up to >100 days after 2 IV infusions at 10 mg/kg. Furthermore, a differential gene expression signature performed in peripheral leukocytes, pre- and post-OSE-127 administration, identified six IL-7 pathway-related genes (BCL2, CISH, PTGER2, DPP4, SOCS2 and FLT3LG). Interestingly, decreased expression of this signature was sustained overtime in accordance with the systemic drug exposure. The differential expression of 4 of these 6 genes (BCL2, CISH, PTGER2, DPP4) has been individually validated by quantitative RT-qPCR, and this novel 4-gene signature appears to follow a dose-dependent expression. Conclusion Our data provide evidence that IL-7 receptor can be blocked in humans without inducing serious adverse events. The signature identified in the peripheral leukocytes of subjects having received OSE-127 represents a robust and simple means to monitor target engagement in the clinical setting. OSE-127 is currently being evaluated in a Phase 2b study in UC patients (CoTikiS study: NCT04882007).

Exosomes derived from reparative M2-like macrophages prevent bone loss in murine periodontitis models via IL-10 mRNA

BackgroundPeriodontitis is characterized by progressive inflammation and alveolar bone loss resulting in tooth loss finally. Macrophages including pro-inflammatory M1-like macrophages and reparative M2-like macrophages play a vital role in inflammation and tissue homeostasis in periodontitis. Among them, reparative M2-like macrophages have been shown to promote tissue repair and prevent bone loss. However, the mechanism of reparative M2 macrophages-induced osteoprotective effect remains elusive.ResultsExosomes from reparative M2-like macrophages (M2-Exos) were isolated and identified successfully. M2-Exos could promote bone marrow stromal cells (BMSCs) osteogenic differentiation while suppressing bone marrow derived macrophage (BMDM) osteoclast formation, and prohibit pathological alveolar bone resorption because of the intercellular communication via exosomes. High expression level of IL-10 mRNA was detected not only in reparative M2-like macrophages but also in M2-Exos. Meanwhile, IL-10 expression level in BMSCs or BMDM was also upregulated significantly after co-culturing with M2-Exos in a concentration-dependent manner. In vitro, recombinant IL-10 proteins had the ability to selectively promote osteogenic differentiation of BMSCs and hinder osteoclast differentiation of BMDM. Moreover, after treatment with M2-Exos and IL-10R antibody together, the capacity of promoting osteogenesis and suppressing osteoclastogenesis of M2-Exos was significantly reversed. In vivo experiments further showed that M2-Exos reduced alveolar bone resorption in mice with periodontitis via IL-10/IL-10R pathway.ConclusionIn conclusion, our results demonstrate that the reparative M2-like macrophages could promote osteogenesis while inhibiting osteoclastogenesis in vitro as well as protect alveolar bone against resorption in vivo significantly. M2-Exos could upregulate the IL-10 cytokines expression of BMSCs and BMDM via delivering exosomal IL-10 mRNA to cells directly, leading to activation of the cellular IL-10/IL-10R pathway to regulate cells differentiation and bone metabolism. These results might partly account for the mechanism of osteoprotective effect of reparative M2-like macrophages and provide a novel perspective and a potential therapeutic approach on improving alveolar resorption by M2-Exos.Graphical

MicroRNA-10a Negatively Regulates CD4+ T Cell IL-10 Production through Suppression of Blimp1

An uncontrolled CD4+ T cell response is a critical hallmark of autoimmune diseases. IL-10, which can be produced by both effector and regulatory CD4+ T cells, plays an essential role in the inhibition of autoimmunity. MicroRNAs are key molecules involved in regulating immune responses. However, how miR-10a regulates CD4+ T cell function in the pathogenesis of intestinal immune responses is not fully understood. In this study, we show that the mice with deficient miR-10a in CD4+ T cells were more resistant to intestinal inflammation upon inflammatory insult. miR-10a-deficient CD4+CD45Rbhi T cells were less colitogenic in Rag -/- mice, in which CD4+ T cell production of IL-10 was increased. miR-10a-deficient CD4+ T cells expressed a higher expression of IL-10 in vitro. Blocking the IL-10/IL-10R pathway in vivo aggravated colitis induced by miR-10a-deficient CD4+CD45Rbhi T cells. Mechanically, miR-10a suppressed CD4+ T cell production of IL-10 through targeting Prdm1, which encodes Blimp1. We further show that that CD4+ T cells lacking Blimp1 produced lower levels of IL-10 and induced more severe colitis in Rag -/- mice. These data thus establish the role of miR-10a in the inhibition of IL-10 production in CD4+ T cells to regulate intestinal homeostasis.

Dual effect of IL-7/IL-7R signalling on the osteoimmunological system: a potential therapeutic target for rheumatoid arthritis.

The IL-7/IL-7R pathway plays a vital role in the immune system, especially in the inflammatory response. Monocytes/macrophages (osteoclast precursors) have been recently recognized as important participants in the osteoclastogenesis of rheumatoid arthritis (RA) patients. Here, we aimed to investigate the therapeutic potential of IL-7/IL-7R pathway in RA and to determine whether it could restrain osteoclastogenic functions and therefore ameliorate RA. Firstly, collagen-induced arthritis (CIA) mice were administered with IL-7Rα-target antibodies to assess their therapeutic effect on arthritis. We found that blockade of the IL-7/IL-7R pathway protected CIA mice from bone destruction in addition to inducing inflammatory remission, by altering the RANKL/RANK/OPG ratio and consequently decreasing osteoclast formation. To explore the effect and mechanism of this pathway, bone marrow cells were induced to osteoclasts and treated with IL-7, a STAT5 inhibitor or supernatants from T cells. The results showed that the IL-7/IL-7R pathway played a direct inhibitory role in osteoclast differentiation via STAT5 signalling pathway in a RANKL-induced manner. We applied flow cytometry to analyse the effect of IL-7 on T-cell RANKL expression and found that IL-7/IL-7R pathway had an indirect role in the osteoclast differentiation process by enhancing the RANKL expression on T cells. In conclusion, the IL-7/IL-7R pathway exhibited a dual effect on osteoclastogenesis of CIA mice by interacting with osteoimmunology processes and could be a novel therapeutic target for autoimmune diseases such as RA.

Randomized phase II study of pembrolizumab (P) alone versus pegilodecakin (PEG) in combination with P as first-line (1L) therapy in patients (pts) with stage IV non-small cell lung cancer (NSCLC) with high PD-L1 expression (CYPRESS 1).

9563 Background: Pembrolizumab (P) is an immune checkpoint inhibitor (CPI) approved to treat 1L advanced NSCLC pts with high PD-L1 expression. PEG + CPI has demonstrated promising efficacy in NSCLC pts in a phase I trial (IVY; NCT02009449; Naing et al., 2019 Lancet Oncol), providing rationale for this randomized phase II trial (CYPRESS 1; NCT03382899). Methods: CYPRESS 1 was an open label phase II trial, for treatment-naïve, ECOG 0-1, PD-L1 high (22C3 clone TPS ≥ 50%), Stage IV NSCLC pts, without known EGFR/ALK mutations. Pts were randomized 1:1 to arm P (received 200mg IV on day 1 of a 21-day cycle) v. arm PEG+P (received P as above + PEG daily of 0.8 mg if weight ≤80kg and 1.6mg if weight> 80 kg up to 35 cycles in each arm). Pts were stratified by tumor histology and must have no prior history of cancer or prior CPI therapy. Primary endpoint was ORR (per RECIST v1.1 by investigator) Secondary endpoints included PFS, OS, and safety. Exploratory endpoints included ORR and PFS by blinded independent central review (BICR). Immune activation biomarkers (baseline and change from baseline) were assessed by serum immunoassay, IHC, and sequencing. Results: As of Dec 6, 2019, 101 pts were randomized to PEG+P (n=51) or P (n=50). Median follow-up time was 10.0 months (95% CI [8.4, 11.1]). Results for PEG+P versus P were: ORR per investigator was 47% v. 44% (p=0.76), ORR per BICR was 53% v. 46%(p=0.78), mPFS per investigator was 6.3 v. 6.1 months with HR = 0.94 (95% CI [0.54, 1.63];p=0.82), mPFS per BICR was 6.4 v. 7.2 months with HR = 1.10 (95%CI [0.62, 1.96]; p=0.74), and mOS was 16.3 months v. not reached with HR = 1.36 (95% CI [0.66, 2.77]; p-value=0.40). Gr ≥3 treatment related adverse events (TRAEs) were 62% for PEG+P versus 19% for P. Gr ≥3 TRAEs with ≥10% incidence included anemia (20% vs. 0%) and thrombocytopenia (12% vs. 2%). Biomarker data on immunostimulatory signals of the IL-10R pathway will be included. Conclusions: Adding PEG to P did not lead to improvement in ORR, PFS, or OS, in 1L advanced NSCLC with high PD-L1 expression. PEG+P arm demonstrated expected safety profile but overall higher toxicity compared to pembrolizumab alone. Clinical trial information: NCT03382899 .

Randomized phase II study of nivolumab (N) alone versus with pegilodecakin (PEG) in combination with N in patients (pts) with post-platinum immunotherapy-naive stage IV non-small cell lung cancer (NSCLC) and no or low PD-L1 expression (CYPRESS 2).

e21744 Background: Nivolumab (N) is an immune checkpoint inhibitor (CPI) approved to treat post-platinum NSCLC as monotherapy. PEG in combination with N has demonstrated promising efficacy in NSCLC pts in a phase I trial (IVY; NCT02009449; Naing et al., 2019 Lancet Oncol), providing rationale for this randomized phase II trial (CYPRESS 2). Methods: CYPRESS 2 was an open label phase II trial, for ECOG 0-1, PD-L1 negative or low (TPS 0-49%), Stage IV NSCLC pts, without known EGFR/ALK mutations. Pts were randomized 1:1 to arm N (240 mg every 14-days or 480 mg every 28-days as decided by investigator) v. arm PEG+N (received N as above + PEG daily of 0.8 mg if weight ≤80kg and 1.6mg if weight > 80 kg). Pts were stratified by tumor histology and smoking history and must have no prior history of cancer or CPI therapy. Primary endpoint was ORR (per RECIST v 1.1 per investigator). Secondary endpoints included PFS, OS, and safety. Exploratory endpoints included immune activation biomarkers (baseline and change from baseline), assessed by immunoassay. Results: As of Aug 28, 2019, 52 pts were randomized to PEG+N (n=27) or N (n=25). Median follow-up time was 11.6 months. The following results were found for PEG+N versus N: ORR 14.8% v. 12.0%, mPFS 1.9 v. 1.9 months with HR = 1.01 (95% CI [0.52, 1.95]), mOS 6.7 v. 10.7 months with HR = 1.87 (95% CI [0.77, 4.53]). Gr ≥3 treatment related adverse events (TRAEs) for PEG+N versus N were 70.4% vs. 16.7%. Gr 3 TRAEs of ≥10% incidence included anemia (40.7% v. 0%), fatigue (18.5% v. 0%), and thrombocytopenia (14.8% v. 0%). In PEG+N arm, increased circulating IL-18, Granzyme B, FasL, and IFNg levels and decreased TGFb levels were observed on treatment. Conclusions: Exploratory pharmacodynamic results were consistent with immunostimulatory signals of the IL-10R pathway. Despite evidence of biological effect, adding PEG to N did not lead to improvement in ORR, PFS, or OS in post-platinum advanced NSCLC with no or low PD-L1 expression. PEG+N arm demonstrated expected safety profile but overall higher toxicity compared to nivolumab alone. Clinical trial information: NCT03382912.

IL-2/IL-2 Receptor Pathway Plays a Crucial Role in the Growth and Malignant Transformation of HTLV-1-Infected T Cells to Develop Adult T-Cell Leukemia.

T cells infected with human T-cell leukemia virus type 1 (HTLV-1) transform into malignant/leukemic cells and develop adult T-cell leukemia (ATL) after a long latency period. The tax (transactivator from the X-gene region) and HBZ (HTLV-1 bZIP factor) genes of HTLV-1 play crucial roles in the development of ATL. The process and mechanism by which HTLV-1-infected T cells acquire malignancy and develop ATL remain to be elucidated. Constitutive expression of interleukin-2 (IL-2) receptor α-chain (IL-2Rα/CD25), induced by the tax and HBZ genes of HTLV-1, on ATL cells implicates the involvement of IL-2/IL-2R pathway in the growth and development of ATL cells in vivo. However, the leukemic cells in the majority of ATL patients appeared unresponsive to IL-2, raising controversies on the role of this pathway for the growth of ATL cells in vivo. Here, we report the establishment of 32 IL-2-dependent T-cell lines infected with HTLV-1 from 26 ATL patients, including eight leukemic cell lines derived from five ATL patients, while no T-cell lines were established without IL-2. We have shown that the IL-2-dependent ATL cell lines evolved into IL-2-independent/-unresponsive growth phase, resembling ATL cells in vivo. Moreover, the IL-2-dependent non-leukemic T-cell lines infected with HTLV-1 acquired IL-2-independency and turned into tumor-producing cancer cells as with the ATL cell lines. HTLV-1-infected T cells in vivo could survive and proliferate depending on IL-2 that was produced in vivo by the HTLV-1-infected T cells of ATL patients and patients with HTLV-1-associated diseases and, acts as a physiological molecule to regulate T-cell growth. These results suggest that ATL cells develop among the HTLV-1-infected T cells growing dependently on IL-2 and that most of the circulating ATL cells progressed to become less responsive to IL-2, acquiring the ability to proliferate without IL-2.

Adult T-cell acute lymphoblastic leukemias with IL7R pathway mutations are slow-responders who do not benefit from allogeneic stem-cell transplantation.

The prognostic value of IL7-receptor pathway (IL7Rp) mutations in T-cell acute lymphoblastic leukemia (T-ALL) remains unclear. We performed a comprehensive study of 200 adult patients with T-ALL included in the GRAALL2003/2005 protocols to address the clinical significance of IL7Rp mutations. Next-generation sequencing of the IL7Rp (IL7R/JAK1/JAK3/STAT5B) revealed that IL7Rp mutations were frequent in adult T-ALL (28%) particularly in immature/early T-cell progenitor (ETP)-ALL. They were associated with mutations of NOTCH-pathway, PHF6, and PRC2 components but not with K/NRAS. IL7Rp mutated (IL7Rpmut) T-ALL were slow-responders, with a high rate of M2/M3 day-8 marrow compared with IL7Rp non-mutated (IL7RpWT) T-ALL (p = 0.002) and minimal residual disease positivity at 6-weeks (MRD1) (p = 0.008) but no difference in MRD2 positivity at 12-weeks. Despite this, no adverse prognosis was evidenced when censored for allogeneic hematopoietic stem cell transplantation (HSCT). In time-dependent analysis, HSCT did not benefit IL7Rpmut patients whereas it was of marked benefit to IL7RpWT cases. IL7Rp-mutations identify a subgroup of slow-responder T-ALLs which benefit from post-induction chemotherapy regimens but not from HSCT. Our data suggest that prior knowledge of the mutation status of IL7Rp may influence HSCT decision and help to guide therapy reduction.

TPD7 inhibits the growth of cutaneous T cell lymphoma H9 cell through regulating IL‐2R signalling pathway

IL‐2R pathway is a key regulator in the development of immune cells and has emerged as a promising drug target in cancer treatment, but there is a scarcity of related inhibitors. TPD7 is a novel biphenyl urea taspine derivate, which has been shown anti‐cancer effect. Here, we demonstrated the anti‐cancer activity of TPD7 in cutaneous T cell lymphoma and investigated the underlying mechanism of TPD7 through IL‐2R signalling. The inhibitory effect of TPD7 on cell viability exhibited a strong correlation with the expression level of IL‐2R, and cutaneous T cell lymphoma H9 and HUT78 cells were most sensitive to TPD7. TPD7 was nicely bound to IL‐2R and down‐regulated the mRNA and protein levels of IL‐2R. Furthermore, TPD7 suppressed the downstream cascades of IL‐2R including JAK/STAT, PI3K/AKT/mTOR and PLCγ/Raf/MAPK signalling, resulting in Bcl‐2 mitochondrial apoptosis pathway and cell cycle proteins CDK/Cyclins regulation. And, these were verified by flow cytometry analysis that TPD7 facilitated cell apoptosis in H9 cells via mitochondrial pathway and impeded cell cycle progression at G2/M phase. TPD7 is a novel anti‐cancer agent and may be a potential candidate for cutaneous T cell lymphoma treatment by regulating IL‐2R signalling pathway.

The Combination of Venetoclax and Tofacitinib Induced Hematological Responses in Patients with Relapse/ Refractory T-ALL with BCL2 Expression and Surface IL7R Expression or IL7R-Pathway Mutations (On behalf of the GRAALL)

Background. We previously reported that IL7R-pathway genes are mutated in 29% of T-ALL and that surface IL7R is expressed in 53% of T-ALL (Rathana K et al. abstract S131, EHA 2019). In these samples, in vitro and in vivo (IL7R+PDX T-ALL) sensitivity to JAK inhibitors is determined by the expression of IL7R regardless of the IL7Rp genomic status. BCL2 inhibition has been shown to be synergistic with the IL7R pathway inhibition (Degrise S et al., Leukemia 2018;32(3):788-800). We therefore explored whether the combination of tofacitinib, a potent JAK3 inhibitor, with venetoclax may improve the hematological status of patients with relapse/refractory T-ALL. Methods. Patients with relapse/refractory T-ALL, with surface IL7R expression or IL7R-pathway mutations and BCL2 expression were eligible if they had failed all available therapeutic options (including clofarabine and/or allogenic HSCT if eligible). Patients were offered to be treated with venetoclax, 100 mg/d day1; 200 mg/d day2; 300 mg/d day3 and 400 mg/day thereafter and for subsequent 28 days cycles combined with tofacitinib, 10mg twice a day started from day 5 cycle 1 (off-label use). Responses were assessed after cycle 1 and cycle 3. Responding patients may continue therapy until relapse, death or allogenic HSCT if eligible. Results. Eight patients were treated including 7 ETP-ALL and 1 T-cell lymphoblastic lymphoma. Median age was 56 years (27-69) and sex ratio (M/F) was 4/4. Four patients were refractory to at least 2 lines of therapy and 4 patients relapsed, all on therapy. Relapsing patients were in failure after at least one salvage therapy. All patients expressed BCL2. A mutation of JAK3 L857P was found in 5 cases including one patient with both JAK3 and JAK1 mutations. except one with a mutation of IL7-R. Other patients expressed IL7R. A response to therapy was observed in 5 out of seven evaluable cases (71%) including 2 CR associated with a negative MRD (sensitivity 10-4) and 3 partial responses (medullar blasts less than 15%). The remaining patient has just started the first cycle of therapy. Duration of responses was 10 months and +6 months (allo HSCT planned) for the 2 patients in CR and 3 months or less for the partial responders. No serious adverse event related to therapy was observed. Conclusion. IL7-pathway is a possible target for therapy with JAK inhibitors in patients with T-ALL in relapse or refractory to conventional therapy. A combination of venetoclax and tofacitinib may offer a potential savage for these patients with limited therapeutic options. Disclosures Chevallier: Daiichi Sankyo: Honoraria; Incyte: Consultancy, Honoraria; Jazz Pharmaceuticals: Honoraria. Dombret:Institut de Recherches Internationales Servier (IRIS): Research Funding; AGIOS: Honoraria; CELGENE: Consultancy, Honoraria. Boissel:NOVARTIS: Consultancy. Rousselot:Pfizer: Research Funding; Incyte: Research Funding. OffLabel Disclosure: Venetoclax in T-ALL Tofacitinib in T-ALL

S131 IL7R EXPRESSION PREDICTS T‐ALL SENSITIVITY TO JAK INHIBITORS REGARDLESS OF IL7R/JAK/STAT MUTATIONAL STATUS

Background:Normal T‐cell development is supported by cytokine signaling with IL7 as key player. This is highlighted by the absence of T‐cells in gamma‐chain SCID‐patients. T‐ALL represents a heterogeneous disease characterized by expansion of immature T‐cells blocked in their differentiation. Despite therapeutic improvements, it remains associated with a poor prognosis mainly due to relapses. This results in a medical need for new therapeutic approaches. Several studies reported the deregulation of IL7R signaling notably via genomic alterations accounting for ∼30% of T‐ALL. In keeping with this, preclinical models supported the possibility to target the IL7R‐pathway (IL7Rp) in IL7Rp‐mutated T‐ALL using pharmacological JAK inhibitors such as ruxolitinib. Moreover, ex vivo culture of primary T‐ALL samples requires addition of IL7 cytokine in culture medium to support leukemic cell survival. Altogether, this data supports a strong dependency of T‐ALL on IL7R signalling. However, the question of which T‐ALL patients may benefit from JAK inhibitors remains unclear.Aims:We aimed to investigate surface IL7R (sIL7R) expression and mutational status of IL7Rp in T‐ALL, and to identify a readout for patient JAK inhibitor sensitivity.Methods:159 T‐ALL samples were prospectively analyzed by FACS for IL7R expression. Genetic data of IL7R pathway genes (IL7R, JAK1/2, STAT5) were assessed on 87 adult T‐ALL enrolled in the ongoing GRAALL‐2014 trial by targeted‐sequencing. 21 patient derived xenograft (PDX) T‐ALL were generated for ex vivo studies including i) phosphoprotein flow analysis of pSTAT5 upon IL7 stimulation and JAK inhibition, ii) apoptosis assay by Annexin V‐PI staining, and iii) proliferation assay using Celltrace.Results:sIL7R was expressed at early stages of normal T‐cell development, downregulated during the cortical stage, and up‐regulated at the mature stage. In T‐ALL, sIL7R was expressed in 84/159 cases (53%). We found IL7Rp mutations in 29% of cases and all IL7Rmut cases expressed sIL7R defining 3 classes of T‐ALL depending on sIL7R expression and mutational status of IL7Rp: IL7R‐/WT, IL7R+/WT, IL7R+/mut. IL7R+ T‐ALLs were mainly of immature non‐ETP, cortical and TCRgd phenotype. These data support frequent and abnormal expression of sIL7R in T‐ALL as regard to normal expression pattern in thymocytes.sIL7R expression was always associated with functional signaling of the receptor: pSTAT5 was activated upon IL7 exposure and abrogated by the addition of ruxolitinib in both normal thymocytes and PDX T‐ALL. Constitutive STAT5 phosphorylation was observed in IL7R+/mut but not in IL7R+/WT PDX T‐ALL. However, pSTAT5 activation reached similar levels in both IL7R+/mut and IL7R+/WT PDX T‐ALL upon IL7 exposure regardless of their mutational status, which was completely reversed by ruxolitinib addition. Ex vivo treatment of PDX T‐ALL with increasing doses of ruxolitinib induced apoptosis and cytostatic effect in both IL7R+/WT and IL7R+/mut PDX T‐ALL.Summary/Conclusion:IL7Rp genes are mutated in 29% in T‐ALL and sIL7R is expressed in 53% of cases. Ruxolitinib induces apoptosis and impairs cell proliferation in sIL7R+ T‐ALL irrespective of IL7Rp mutational status. Our data shows that sensitivity to JAK inhibitors is determined by the expression of IL7R regardless of the IL7Rp genomic status. IL7R expression is a readout for JAK inhibitors sensitivity, and provides a fast and accurate companion theranostic tool using flow‐cytometry.

Inducible IL-7 Hyperexpression Influences Lymphocyte Homeostasis and Function and Increases Allograft Rejection.

The IL-7/IL-7R pathway is essential for lymphocyte development and disturbances in the pathway can lead to immune deficiency or T cell mediated destruction. Here, the effect of transient hyperexpression of IL-7 was investigated on immune regulation and allograft rejection under immunosuppression. An experimental in vivo immunosuppressive mouse model of IL-7 hyperexpression was developed using transgenic mice (C57BL/6 background) carrying a tetracycline inducible IL-7 expression cassette, which allowed the temporally controlled induction of IL-7 hyperexpression by Dexamethasone and Doxycycline treatment. Upon induction of IL-7, the B220+ c-kit+ Pro/Pre-B I compartment in the bone marrow increased as compared to control mice in a serum IL-7 concentration-correlated manner. IL-7 hyperexpression also preferentially increased the population size of memory CD8+ T cells in secondary lymphoid organs, and reduced the proportion of CD4+Foxp3+ T regulatory cells. Of relevance to disease, conventional CD4+ T cells from an IL-7-rich milieu escaped T regulatory cell-mediated suppression in vitro and in a model of autoimmune diabetes in vivo. These findings were validated using an IL-7/anti-IL7 complex treatment mouse model to create an IL-7 rich environment. To study the effect of IL-7 on islet graft survival in a mismatched allograft model, BALB/c mice were rendered diabetic by streptozotocin und transplanted with IL-7-inducible or control islets from C57BL/6 mice. As expected, Dexamethasone and Doxycycline treatment prolonged graft median survival as compared to the untreated control group in this transplantation mouse model. However, upon induction of local IL-7 hyperexpression in the transplanted islets, graft survival time was decreased and this was accompanied by an increased CD4+ and CD8+ T cell infiltration in the islets. Altogether, the findings show that transient elevations of IL-7 can impair immune regulation and lead to graft loss also under immune suppression.

Activation of CRLF2/IL7RA Signaling in Normal Human Cord Blood Hematopoietic Progenitors Induces Philadelphia-like B-Cell Precursor Pre-Leukemia and Leukemia In Vivo

Philadelphia-like (Ph-like) B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a subgroup of BCP-ALL with an expression pattern similar to BCR-ABL+ BCP-ALL that is associated with poor prognosis.Aberrant expression of CRLF2 in BCP-ALL constitutes the majority of Ph-like BCP-ALL cases. CRLF2 is a receptor subunit that together with the IL7RA subunit comprises the receptor of the proinflammatory cytokine TSLP. Though activation of the IL7R pathway is commonly associated with T-cell malignancies, we previously described IL7RA-activating mutations in BCP-ALL predominantly in the context of CRLF2 aberrant expression (Shochat C. et al. J. Exp. Med. 2011).Here we aimed to test the role of aberrations in CRLF2 and IL7RA in the development of Ph-Like BCP-ALL. Both CRLF2 and TSLP differ extensively between mice and human in amino acid sequence and in lineage expression pattern; loss-of-function germline mutations in IL7RA are associated with lack of B and T cells in mice but with lack of only T cells in humans. Hence, we chose to test the hypothesis that activation of CRLF2/IL7RA contributes to the development of Ph-like BCP-ALL in the context of human lymphopoiesis by using a human xenograft system.To aberrantly activate TSLP/IL7 signaling, we transduced cord-blood (CB) CD34+ hematopoietic progenitors with a set of lentiviral vectors carrying CRLF2 and/or IL7RA [(wild type (IL7RAwt) or IL7R bearing an activating mutation (IL7RAins)] under a B-cell promoter/enhancer (to accentuate B-cell lineage expression). The backbone vector (BB) expressing GFP was used as a control. Transduced CB cells were transplanted into NOD/LtSz-scid IL2Rγnull (NSG) mice and engrafted cells were analyzed 24-30 weeks after transplantation. To test for self-renewal capacity, BM cells from primary engrafted mice were serially transplanted into secondary recipients and the occurrence of human engraftment was tested 24-30 weeks after transplantation.Enforced expression of activated IL7RA with or without CRLF2 led to a significant block in B-cell development at the B-cell progenitor stage (CD19+CD10+sIgM-) in vivo resembling the differentiation stage of leukemic cells (figure Bi). Repertoire sequencing of CD10+CD19+-transduced cells that were sorted from BM of transplanted mice revealed a significantly higher population of DJ-rearranged cells in the CRLF2-IL7RAins-transduced population than in BB-transduced cells (mean ratio of DJ/total rearrangement: BB:0.35+/-0.024, CRLF2-IL7RAins:0.76+/- 0.07, p=0.039, n=3 paired cord blood), in agreement with the early differentiation block phenotype measured by immunophenotyping. These cells furthermore exhibited a Ph-like gene expression pattern when compared to BB-transduced cells in gene set enrichment analysis.Overexpression of IL7RA alone significantly enhanced the early-B fraction (CD19+CD10+CD34+) in the BM of transplanted mice (figure Bii). Additionally, aberrant expression of IL7RA enhanced self-renewal capacity as was evident by an increased ability of the transduced cells to engraft in secondary recipients (number of mice with detectable human engraftment out of secondary transplanted mice: BB:0/6, CRLF2-IL7RAwt:0/3, CRLF2-IL7RAinst:0/3, IL7RAwt-GFP:3/6, IL7RAins-GFP:5/8).Notably, in one case, secondary transplantation of IL7RAins-transduced CB triggered the development of acute BCP-ALL. The leukemic cells (CD19+CD10+CD34+sIgM-) were clonal as validated by V(D)J rearrangement (figure Cii), had the ability to further propagate in serial transplantations and gained secondary Ph-like BCP-ALL-characteristic chromosomal deletions in the short arm of chromosome 9 (in the region including the genes for CDKN2A/B, PAX5 and JAK2) and the short arm of chromosome 7 (the region including IKZF1) (figure Ciii).These results support the hypothesis that aberrant activation of the CRLF2/IL7RA pathway in human B-cell lineage progenitors creates a pre-leukemic state by arresting differentiation of B-cell progenitors, instating Ph-like expression pattern and inducing self-renewal. This is the first model of de novo Ph-like BCP-ALL development from normal human hematopoietic progenitors in vivo. Additionally, we present here a first direct in vivo demonstration of a role for IL7 in human B-cell development. DisclosuresNo relevant conflicts of interest to declare.

Inhibiting Janus Kinase 1 and BCL-2 to treat T cell acute lymphoblastic leukemia with IL7-Rα mutations.

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Current chemotherapy is quite toxic in growing children and more directed therapeutics are being sought. The IL-7R pathway is a major driver of ALL and here we evaluate two drugs directed to that pathway using a model of T cell ALL. Mutant gain-of-function IL-7Rα was transduced into an IL-7-dependent murine thymocyte line conferring ligand-independent survival and growth. JAK1 is associated with IL-7Rα and mediates signaling from the mutant receptor. In vitro, treating the transformed cell line with the JAK1/2 inhibitor ruxolitinib inhibited ligand-independent signaling and induced cell death. Transfer of the transformed cell line into mice resulted in aggressive leukemia and untreated mice succumbed in about three weeks. Treatment with ruxolitinib incorporated into chow showed a potent therapeutic benefit with reduction in leukemic burden and extension of survival. BCL-2 is an anti-apoptotic downstream mediator of the IL-7R survival mechanism. Venetoclax, an inhibitor of BCL-2, showed activity against the transformed cell line in vitro and could be combined with ruxolitinib in vivo. These findings support the therapeutic potential of treating T-ALL by targeting the IL-7R pathway.