IGHV Unmutated Chronic Lymphocytic Leukemia (CLL) B Cells Are More Susceptible to Spontaneous Apoptosis Than Mutated CLL B Cells and Are Subject to the Anti-Apoptotic Effect of Environmental Signals

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2431-2431
Author(s):  
Marta Coscia ◽  
Francesca Pantaleoni ◽  
Chiara Riganti ◽  
Candida Vitale ◽  
Micol Rigoni ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Board Of Directors ◽  
Stromal Cells ◽  
Peripheral Blood ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Spontaneous Apoptosis ◽  
Advisory Committees

Abstract Abstract 2431 Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease. A very reliable prognosticator is the mutational status of the tumor immunoglobulin heavy chain variable region (IGHV): patients with unmutated (UM) IGHV have a worse prognosis than patients with mutated (M) IGHV. Soluble factors (i.e. IL-4 and CD40L) and cellular components of the local microenvironment [i.e. bone marrow stromal cells (BMSC) and nurse-like cells (NLCs)] are important survival factors for CLL B cells. It is currently unknown to what extent UM and M CLL cells depend on the local microenvironment for their survival. We have evaluated the spontaneous apoptotic rate of tumor cells isolated by immunomagnetic selection from the peripheral blood (PB) of M and UM CLL patients. Both M and UM CLL B cells underwent spontaneous apoptosis throughout the culture period. However, the UM CLL B cells showed a significantly higher degree of apoptosis in 7-day cultures as compared to M CLL B cells. In both M and UM CLL B cells, high basal levels of Bcl-2 expression and NF-kB activity were detected. On day 7, the percentage of Bcl-2+ leukemic cells was significantly lower in UM than in M CLL B cells. EMSA test showed that NF-kB was totally inactivated in UM CLL B cells and only partially reduced in M CLL B cells. Quantitative analysis of RelA and RelB subunits showed that NF-kB inactivation in UM CLL B cells consisted in a strong reduction of both RelA and RelB nuclear expression. CD40L, IL-4 and stromal cells significantly improved UM CLL B cells viability and significantly recovered Bcl-2 expression. The protective effect exerted by these stimuli was totally independent from the recovery of NF-kB expression. Indeed, after 7 days of culture, the UM CLL B cells had completely lost the nuclear form of NF-kB, and none of the stimuli was capable of restoring it. We observed that UM CLL cells were less susceptible to spontaneous apoptosis when cultured as unfractionated peripheral blood mononuclear cells (M or UM PBMC) as compared to purified leukemic cells (M and UM CLL B cells). The reduced apoptosis detected in UM PBMC was accompanied by a retained expression of Bcl-2 and by a restored activity of NF-kB and suggested the presence of a pro-survival element in the peripheral blood of these patients. To investigate the role of NLC in rescuing UM CLL B cells from apoptosis we first evaluated whether M and UM PBMC generated NLC with the same efficiency. Unexpectedly, the former generated significantly higher numbers of NLC than UM PBMC. Despite the lack of generation of NLC, CLL B cells viability was very similar in the non-adherent fraction of M and UM PBMC on day 7 and 14 of culture. This observation ruled out a role for NLC in supporting UM CLL B cells survival. Conversely, a pro-survival effect on UM CLL B cells was exerted by autologous T cells. Indeed, a significant reduction in the apoptotic rate of leukemic cells was observed when purified UM CLL B cells were cultured in the presence of autologous peripheral blood T cells (UM CLL B cell/T cell co-cultures). NF-kB activity was completely lost in UM CLL B cells cultured for 7 days in medium alone whereas it was restored in UM CLL B cells / T cells co-cultures. The prosurvival effect of circulating T cells was exerted both in cell-to-cell contact and in trans-well condition and was associated to increased secretions of tumor necrosis factor-alpha (TNF-α), platelet-derived growth factor (PDGF)-BB and interleukin-8 (IL-8) as detected by analyses of supernatants through a Multiplex system. These data indicate that despite their more aggressive features, UM CLL B cells are more susceptible to spontaneous apoptosis and depend from environmental prosurvival signals. This vulnerability of UM CLL B cells can be exploited as a selective target of therapeutic interventions. Disclosures: Boccadoro: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Massaia: Novartis: Honoraria, Research Funding.

scholarly journals Synergistic Role of Leukemic and Non-Leukemic Immune Repertoires in CD8+ T-Cell Large Granular Lymphocytic Leukemia As Identified By Single-Cell Transcriptomics

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1318-1318
Author(s):  
Dipabarna Bhattacharya ◽  
Jani Huuhtanen ◽  
Matti Kankainen ◽  
Tapio Lönnberg ◽  
Cassandra M Kerr ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Healthy Controls ◽  
Advisory Committees ◽  
Cell Clones ◽  
Tcr Repertoire

Abstract Background: T-cell large granular lymphocytic leukemia (T-LGLL), a rare lymphoproliferative disorder of mature T cells, is characterized by the accumulation of activated effector T cells leading to a clonally restricted T-cell receptor (TCR) repertoire. Chronic antigen stimulation together with activating somatic STAT3 mutations have been proposed to lead to clonal expansion of leukemic cells. However, no holistic research has been done to show how leukemic and non-leukemic cells liaise to sustain abnormal immune reactivity in T-LGLL. Methods: We investigated the transcriptome and TCR repertoire in T-LGLL using: 1) single-cell RNA and TCR (scRNA+TCRαβ) sequencing from CD45+ sorted blood cells (T-LGLL n=11, healthy n=6), 2) TCRβ sequencing from blood mononuclear cells (T-LGLL n=48, healthy n=823), 3) bulk RNA sequencing (T-LGLL n=15, healthy n=5), 4) plasma cytokine profiling (T-LGLL n=9, healthy n=9), and 5) flow cytometry validations (T-LGLL n=6, healthy n=6) (Figure) Results: ScRNA+TCRαβ-seq data revealed that in healthy controls, hyperexpanded CD8+ T-cell clones (at least 10 cells with identical TCRs) preferentially had an effector memory phenotype, whereas in T-LGLL, the hyperexpanded clonotypes represented a more cytotoxic (increased expression of GZMB, PRF1, KLRB1) and exhausted (LAG3 and TIGIT) phenotype. Using flow cytometry, we confirmed that upon anti-CD3/CD28/CD49 antibody stimulation, T-LGLL clones (CD8+CD57+) expressed higher levels of cytotoxic proteins (GZMA /GZMB , PRF1) but were deficient in degranulation responses and cytokine secretion as measured by expression of CD107a/b and TNFα/IFNγ, respectively. Focused re-clustering of the extracted T-LGLL clones from the scRNA+TCRαβ-seq data revealed considerable heterogeneity among the T-LGLL clones and partly separated the mutated (mt) STAT3 and wild type (wt) STAT3 clones. STAT3wt clones upregulated T-cell activation and TCR signaling pathways, with a higher cytotoxicity and lower exhaustion score as compared to STAT3mt clones. This was validated with bulk RNA-seq data. To understand the antigen specificities of the T-LGLL clones, we combined previously profiled T-LGLL TCRs with our data to form the largest described dataset of 200 T-LGLL clones from 170 patients. Notably, T-LGLL clones were found to be private to each patient. Furthermore, the analysis by GLIPH2 algorithm grouping TCRs did not reveal detectable structural similarities, suggesting the absence of a unifying antigen in T-LGLL. However, in 67% of T-LGLL patients, the TCRs of leukemic clones shared amino acid level similarities with the rest of the non-leukemic TCR repertoire suggesting that the clonal and non-clonal immune repertoires are connected via common target antigens. To analyze the non-clonal immune repertoire in T-LGLL in detail, we compared our data to other published scRNAseq data from solid tumors (n=4) and hematologic cancers (n=8) and healthy controls (n=6). The analysis revealed that in T-LGLL also the non-leukemic CD8+ and CD4+ T cells were more mature, cytotoxic, and clonally restricted. When compared to healthy controls and other cancer patients, in non-leukemic T-LGLL the most upregulated pathway was IFNγ response. Finally, most of the upregulated cytokines in T-LGLL (e.g., CCL2/3/7, CXCL10/11, IL15RA) were secreted predominantly by monocytes and dendritic cells, which also had upregulated HLA class II expression and enhanced scavenging potential in T-LGLL patients. Ligand-receptor analysis with CellPhoneDB revealed that the number of predicted cell-cell interactions was significantly higher in T-LGLL as compared to reactive T-cell clones in healthy controls. The most co-stimulatory interactions (e.g., CD2-CD58, TNFSF14-TNFRSF14) occurred between the IFNγ secreting T-LGLL clones and the pro-inflammatory cytokine secreting monocytes. Conclusions: Our study shows a synergistic interplay between the leukemic and non-leukemic immune cell repertoires in T-LGLL, where an aberrant antigen-driven immune response including hyperexpanded CD8+ T-LGLL cells, non-leukemic CD8+ cells, CD4+ cells, and monocytes contribute to the persistence of the T-LGLL clones. Our results provide a rationale to prioritize therapies that target the entire immune repertoire and not only the T-LGLL clones in patients with T-LGLL. Figure 1 Figure 1. Disclosures Loughran: Kymera Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bioniz Therapeutics: Membership on an entity's Board of Directors or advisory committees; Keystone Nano: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. Maciejewski: Alexion: Consultancy; Novartis: Consultancy; Regeneron: Consultancy; Bristol Myers Squibb/Celgene: Consultancy. Mustjoki: Novartis: Research Funding; BMS: Research Funding; Janpix: Research Funding; Pfizer: Research Funding.

TRIS (DIBENZYLIDENEACETONE) Dipalladium a Small-Molecule Palladium Complex Is Effective in the Induction of Apoptosis for B-Chronic Lymphocytic Leukemia B-Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2851-2851
Author(s):  
Neil Kay ◽  
Traci Sassoon ◽  
Charla Secreto ◽  
Asish K Ghosh ◽  
Jack L Arbiser
Keyword(s):  
B Cells ◽  
B Cell ◽  
Board Of Directors ◽  
Stromal Cells ◽  
Research Funding ◽  
Palladium Complex ◽  
Lymphocytic Leukemia ◽  
Advisory Committees ◽  
Specific Antibodies ◽  
Induction Of Apoptosis

Abstract Abstract 2851 Background: In an attempt to better treat B-Chronic Lymphocytic Leukemia (CLL) patients, we have examined a unique organometallic complex called Tris (dibenzylideneacetone) dipalladium (Tris DBA). This novel agent is a small-molecule palladium complex shown to have antiproliferative activity against melanoma cells and possible antitumor activity. Tris DBA is known to inhibit activation of signaling molecules such as PI3K and STAT-3, critical factors in CLL B-cell survival and resistance to therapeutic agents. Because B-CLL remains incurable and treatment strategies challenging, our findings may be useful in pursing new therapies to improve patient care. Therefore, this information prompted us to investigate whether Tris DBA could induce apoptosis in CLL B-cells. Method of Approach: Primary leukemic B-cells from CLL patients were cultured in serum free media and treated at 2 × 106 cells per ml with vehicle or various doses of Tris DBA (1 – 10 μg/ml) for 24 – 72 hours. After treatment, cells were analyzed for apoptosis by a FITC-labeled annexin-V/propidium iodide assay using the FACScan. To assess changes in anti-apoptotic proteins, CLL-B cells were cultured for 24 hours with either vehicle or 2.5μg/mL of Tris DBA. Total protein extracts were used for immunoblot methodology with specific antibodies. In some experiments we developed primary marrow stromal cells (MSC) that when nearly confluent were used for co-culture experiments in the presence of freshly isolated CLL B-cells with various chemotherapeutic drugs and/or Tris DBA. Finally, we compared CLL patients with known immunoglobulin heavy chain variable region (IgVH) status because of the clear differences in clinical outcome for these two prognostic subgroups. Results: CLL B-cells were shown to be sensitive to Tris-DBA with a steep dose response curve that significantly increased apoptosis over control levels as early as 24 hours of culture. Thus the LD50 of Tris DBA was between 2.5 and 5.0 μg/ml for the CLL B-cells who were IgVH mutated while between 5 and 7.5μg/ml for the unmutated status CLL B cells (n=10). Normal B or T lymphocytes were found to be equally sensitive to Tris DBA when compared to CLL B-cells however mesenchymal stromal cells (MSC) from CLL marrow (CLL MSC) were far less sensitive to the Tris DBA drug. Thus the LD50 for normal T cells, B cells or NK cells was between 2.5 and 5.0 μg/ml while the LD50 for the MSC was not reached over the dose range of 1–10 μg/ml. When CLL B-cells were added to CLL derived primary MSC in the presence of increasing concentrations of Tris DBA (2.5–10 μg/ml), the cytotoxic impact of Tris DBA on CLL B-cells could be overcome in the presence of MSC. To delineate the mechanism of apoptosis induction of CLL B-cells, we treated CLL B-cells with sub-lethal dose of Tris DBA and prepared cell lysates for Western blot analyses. We found that the anti-apoptotic proteins XIAP and Bcl-2, but not Mcl-1, were down regulated in Tris- DBA-treated leukemic B-cells. In addition, phosphorylation levels of Akt and STAT-3 were inhibited with exposure to Tris DBA as measured by Western blot using specific antibodies. Finally, we studied if Tris DBA could be synergistic or additive with fludarabine in induction of apoptosis of CLL B- cells. Interestingly, we found that in 2 of 3 assays there was synergy between Tris DBA and fludarabine in the enhancement of CLL B-cell apoptosis. Conclusions: We have established that a unique compound, Tris dipalladium, is effective at inducing apoptosis in CLL B-cells whether these leukemic cells are IGVH mutated (low risk) or unmutated (high risk). In addition this compound can modify the levels of XIAP and Bcl-2, Akt and STAT3 activation in the leukemic B-cells. Importantly, by itself the Tris DBA is effective even in the presence of stromal cells albeit losing some effectiveness at high doses in the co-culture and can generate synergy when added to a purine nucleoside for induction of B-cell apoptosis. In total these findings support future clinical applications of this compound in treating CLL patients. Disclosures: Kay: Biothera: Research Funding; Clegene: Research Funding; Cephalon: Research Funding; Genentech: Research Funding; Glaxo Smith Kline: Research Funding; Hospira: Research Funding; Novartis: Research Funding; Supergen: Research Funding; Calistoga: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Emergent Biosolutions (Formerly Trubion): Membership on an entity's Board of Directors or advisory committees. Arbiser:Natuderm: Patents & Royalties.

scholarly journals Pre-Existing T Cell Subsets Determine Anti-PD1 Blockade Response in Richter's Transformation

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 42-43
Author(s):  
Prajish Iyer ◽  
Lu Yang ◽  
Zhi-Zhang Yang ◽  
Charla R. Secreto ◽  
Sutapa Sinha ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Single Cell ◽  
Board Of Directors ◽  
Peripheral Blood ◽  
Research Funding ◽  
Gene Signature ◽  
T Cell Subsets ◽  
Rna Seq ◽  
Advisory Committees

Despite recent developments in the therapy of chronic lymphocytic leukemia (CLL), Richter's transformation (RT), an aggressive lymphoma, remains a clinical challenge. Immune checkpoint inhibitor (ICI) therapy has shown promise in selective lymphoma types, however, only 30-40% RT patients respond to anti-PD1 pembrolizumab; while the underlying CLL failed to respond and 10% CLL patients progress rapidly within 2 months of treatment. Studies indicate pre-existing T cells in tumor biopsies are associated with a greater anti-PD1 response, hence we hypothesized that pre-existing T cell subset characteristics and regulation in anti-PD1 responders differed from those who progressed in CLL. We used mass cytometry (CyTOF) to analyze T cell subsets isolated from peripheral blood mononuclear cells (PBMCs) from 19 patients with who received pembrolizumab as a single agent. PBMCs were obtained baseline(pre-therapy) and within 3 months of therapy initiation. Among this cohort, 3 patients had complete or partial response (responders), 2 patients had rapid disease progression (progressors) (Fig. A), and 14 had stable disease (non-responders) within the first 3 months of therapy. CyTOF analysis revealed that Treg subsets in responders as compared with progressors or non-responders (MFI -55 vs.30, p=0.001) at both baseline and post-therapy were increased (Fig. B). This quantitative analysis indicated an existing difference in Tregs and distinct molecular dynamic changes in response to pembrolizumab between responders and progressors. To delineate the T cell characteristics in progressors and responders, we performed single-cell RNA-seq (SC-RNA-seq; 10X Genomics platform) using T (CD3+) cells enriched from PBMCs derived from three patients (1 responder: RS2; 2 progressors: CLL14, CLL17) before and after treatment. A total of ~10000 cells were captured and an average of 1215 genes was detected per cell. Using a clustering approach (Seurat V3.1.5), we identified 7 T cell clusters based on transcriptional signature (Fig.C). Responders had a larger fraction of Tregs (Cluster 5) as compared with progressors (p=0.03, Fig. D), and these Tregs showed an IFN-related gene signature (Fig. E). To determine any changes in the cellular circuitry in Tregs between responders and progressors, we used FOXP3, CD25, and CD127 as markers for Tregs in our SC-RNA-seq data. We saw a greater expression of FOXP3, CD25, CD127, in RS2 in comparison to CLL17 and CLL14. Gene set enrichment analysis (GSEA) revealed the upregulation of genes involved in lymphocyte activation and FOXP3-regulated Treg development-related pathways in the responder's Tregs (Fig.F). Together, the greater expression of genes involved in Treg activation may reduce the suppressive functions of Tregs, which led to the response to anti-PD1 treatment seen in RS2 consistent with Tregs in melanoma. To delineate any state changes in T cells between progressors and responder, we performed trajectory analysis using Monocle (R package tool) and identified enrichment of MYC/TNF/IFNG gene signature in state 1 and an effector T signature in state 3 For RS2 after treatment (p=0.003), indicating pembrolizumab induced proliferative and functional T cell signatures in the responder only. Further, our single-cell results were supported by the T cell receptor (TCR beta) repertoire analysis (Adaptive Biotechnology). As an inverse measure of TCR diversity, productive TCR clonality in CLL14 and CLL17 samples was 0.638 and 0.408 at baseline, respectively. Fifty percent of all peripheral blood T cells were represented by one large TCR clone in CLL14(progressor) suggesting tumor related T-cell clone expansion. In contrast, RS2(responder) contained a profile of diverse T cell clones with a clonality of 0.027 (Fig. H). Pembrolizumab therapy did not change the clonality of the three patients during the treatment course (data not shown). In summary, we identified enriched Treg signatures delineating responders from progressors on pembrolizumab treatment, paradoxical to the current understanding of T cell subsets in solid tumors. However, these data are consistent with the recent observation that the presence of Tregs suggests a better prognosis in Hodgkin lymphoma, Follicular lymphoma, and other hematological malignancies. Figure 1 Disclosures Kay: Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Rigel: Membership on an entity's Board of Directors or advisory committees; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Cytomx: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta Pharma: Research Funding; Sunesis: Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; MEI Pharma: Research Funding. Ansell:AI Therapeutics: Research Funding; Takeda: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Bristol Myers Squibb: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; ADC Therapeutics: Research Funding. Ding:Astra Zeneca: Research Funding; Abbvie: Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; DTRM: Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. OffLabel Disclosure: pembrolizumab

The Defective Proliferation of Vgamma9Vdelta2 T Cells to Zoledronic Acid In Chronic Lymphocytic Leukemia (CLL) Is a Powerful Time to First Treatment (TFT) Predictor Associated with the IGHV Mutational Status

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3602-3602
Author(s):  
Marta Coscia ◽  
Candida Vitale ◽  
Silvia Peola ◽  
Chiara Riganti ◽  
Daniela Angelini ◽  
...  
Keyword(s):  
T Cells ◽  
Zoledronic Acid ◽  
Board Of Directors ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Effector Memory ◽  
Advisory Committees ◽  
Mutational Status ◽  
Intermediate Metabolites ◽  
Stimulation Of

Abstract Abstract 3602 The clinical course of chronic lymphocytic leukemia (CLL) depends on the intrinsic tumor cell features but also on the interactions between tumor cells, local microenvironment and host immunity. The interplay between CLL cells and conventional αβ T cells has already been investigated in details, whereas very little is known about the role of Vgamma9Vdelta2 T cells. These cells have intrinsic antitumor properties which can be further enhanced by stimulation with aminobisphosphonates such as zoledronic acid (ZA) via monocytes or other antigen-presenting cells. ZA targets the mevalonate (Mev) pathway and induces the intracellular accumulation and release of intermediate metabolites, like isopentenyl pyrophosphate (IPP), which are very similar to the natural ligands of Vgamma9Vdelta2 T cells. In this study we have performed a phenotypic and functional analysis of Vgamma9Vdelta2 T cells in 93 untreated CLL patients and correlated the results with intrinsic CLL cell features and clinical outcome. Stimulation of peripheral blood mononuclear cells with ZA induced Vgamma9Vdelta2 T cell proliferation in 47/93 patients (responders, R), but not in 46/93 patients (non-responders, NR). Vgamma9Vdelta2 T-cell subset distribution of R CLL was similar to healthy donors, whereas effector memory (EM) and terminally differentiated effector memory (TEMRA) cells predominated in NR CLL. A significant association was found between the R/NR status of Vgamma9Vdelta2 T cells and the mutational status of the tumor IGHV genes: 77% of R patients were M, whereas 70% of UM patients were NR. To test the hypothesis that this difference reflected a different activity of the Mev pathway in M and UM CLL cells, we performed a bioinformatic elaboration of data obtained from gene expression profiling of CLL cells and a biochemical quantification of the Mev pathway in CLL cells including the intermediate metabolites farnesyl pyrophosphate (FPP) and IPP, and the final product cholesterol. The Mev pathway was significantly more active in UM than in M CLL cells, suggesting that the IPP overproduction by UM CLL cells is responsible for a chronic stimulation of Vgamma9Vdelta2 T cells leading to their differentiation into EM and TEMRA cells. This biochemical-driven immunoediting process has clinical implications. After a median follow-up of 46 months from diagnosis, univariate analysis identified R status as a predictor of reduced TFT (NR: 59 months vs R: not reached; p=0.01). The R/NR status also allows to further identify two subsets in UM CLL patients (R-UM and NR-UM) with significantly different TFT (NR-UM: 32 months vs R-UM: not reached; p=0.02). In multivariate analysis, Binet stage (P=0.027), IGHV mutational status (p=0.016), R/NR status (p=0.007), high and low-risk cytogenetic abnormalities (p<0.001) and lymphocytosis at the time of diagnosis (p<0.001) were independent TFT predictors. In conclusion, we have identified a novel TFT predictor based on a putative interaction between the Mev pathway of CLL cells and Vgamma9Vdelta2 T cells. These results further strengthen the importance of tumor-host immune interactions in CLL evolution. Disclosures: Boccadoro: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Massaia:Novartis: Honoraria, Research Funding.

Increased Activity of Aldehyde Dehydrogenase, a Stem/Progenitor Cell Marker, in Chronic Lymphocytic Leukemia,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3867-3867
Author(s):  
Raymond P. Wu ◽  
Christina C.N. Wu ◽  
Tomoko Hayashi ◽  
Laura Z. Rassenti ◽  
Thomas J. Kipps ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Board Of Directors ◽  
Research Funding ◽  
Progenitor Cell ◽  
Lymphocytic Leukemia ◽  
Cell Marker ◽  
Aldh Activity ◽  
Advisory Committees ◽  
Aldefluor Assay

Abstract Abstract 3867 Introduction: Despite their mature appearance, the B cells from chronic lymphocytic leukemia (CLL) possess immature characteristics both functionally and biochemically. CLL B cells display known biochemical markers characteristic of cells early in the blood lineage, including ROR1, Wnt16, and LEF1. In addition, CLL B cells have higher levels of Reactive Oxygen Species (ROS) and of the oxidant-induced transcription factor Nrf2 [NFE2L2], compared to normal peripheral blood mononuclear cells (PBMC). Intracellular ROS status has been suggested to be a marker of cancer stem/progenitor cells possibly due to their high expression of oncogenes. Downstream targets of Nrf2 include the Aldehyde dehydrogenase [ALDH] enzymes, which are believed to play a crucial role in stem cell biology because they protect the cells against oxidative stress caused by accumulation of aldehydes. Here, we use ALDH activity to visualize populations of CLL B cells that may have stem/progenitor properties. Materials and Methods: Isolated PBMC from normal donors and CLL patients with aggressive and indolent disease were stained for ALDH activity with an Aldefluor assay kit (StemCell Technologies). The ALDH inhibitor, diethylaminobenzaldehyde (DEAB), was used to confirm that the fluorescent activity was due to ALDH activity. At the end of the Aldefluor assay, the cells were stained for cell surface markers, CD19, CD5, CD38 and CD34. 50,000 total events were collected for FACS analysis. Normalized Mean Fluorescence Intensity (MFI) values were calculated by dividing each MFI value to average MFI value of normal CD19+ cells for each experiment. Data analyses were performed by FlowJo software and Prizm. P-values were calculated by One-Way ANOVA analysis with Post-Bonferroni's multiple comparison test. Results: We examine the level of ALDH expression and activity in CD19+ cells of healthy donors (n = 9), CLL samples that expressed unmutated IgVH and that were ZAP-70 positive (defined as “aggressive”, n = 14) or samples that expressed mutated IgVH and were ZAP-70 negative (defined as “indolent”, n=12). CLL B cells from patients with aggressive disease had significantly higher ALDH activities compared to normal B cells (p < 0.001) and indolent CLL B cells (p < 0.05) (Figure1). Indolent CLL B cells also have higher level of ALDH activities compared to normal B cells (p < 0.01) (Figure1). Treatment with the ALDH inhibitor, DEAB, suppressed the increased fluorescence observed in CLL B cells. In addition, ALDH high CLL B cells are CD34 negative. These data show that CLL B cells express a marker known to be associated with stem/progenitor cells, but these populations are different from CD34 positive hematopoietic stem cells. In addition, our data show that a stem/progenitor cell marker is associated with the pathogenesis of CLL. Disclosures: Kipps: Igenica: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Research Funding; Abbot Industries: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; GSK: Research Funding; Gilead Sciences: Consultancy, Research Funding; Amgen: Research Funding.

Persistent Impairments in Humoral and Cellular Immunity in Patients with Immune Thrombocytopenia Treated with Rituximab: A Sub-Study of a Randomized Controlled Trial

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 492-492
Author(s):  
Ishac Nazi ◽  
John G. Kelton ◽  
Mark Larche ◽  
Denis P. Snider ◽  
Jane C. Moore ◽  
...  
Keyword(s):  
T Cells ◽  
Placebo Group ◽  
B Cells ◽  
Antibody Response ◽  
Board Of Directors ◽  
Bactericidal Activity ◽  
Research Funding ◽  
Fold Increase ◽  
Advisory Committees ◽  
Adequate Antibody Response

Abstract Abstract 492 Background: The anti-CD20 antibody, rituximab, is increasingly being used as a treatment for immune thrombocytopenia (ITP). The concern about rare occurrences of progressive multifocal leukoencephalopathy in this population and the reliance on vaccine responses in patients who ultimately require splenectomy calls for additional studies into the integrity of the immune system after rituximab treatment. The objective of this study was to evaluate both the antibody and cellular responses to the Streptococcus pneumoniae polysaccharide vaccine and to the Haemophilus influenza type b (Hib) conjugate vaccine in rituximab-treated patients with ITP. Methods: Adults with primary ITP and a platelet count below 30 x109/L who had participated in a randomized trial of rituximab or placebo were eligible for this prospective sub-study. Six months after the study intervention, patients were given the S. pneumoniae polysaccharide vaccine (Pneumovax-23®, Merck) and the Hib conjugate vaccine (ActHIB®, Aventis). Antibodies against the pneumococcal capsular polysaccharide (anti-PCP) and Hib polyribosyl-ribitol phosphate (anti-PRP) were measured by EIA. A bactericidal assay was used to measure the ability to eradicate Hib in culture. An adequate antibody response was defined as a 4-fold increase in antibody concentration from baseline in the first month post vaccination. IgG anti-PRP ≥ 1 μg/mL was considered protective. For the bactericidal assay, a 4-fold increase from baseline was considered positive. CD3+ T-cells and total (CD19+), naïve (CD19+, CD27−), memory (CD19+, CD27+, CD38−) and pre-plasma (CD19low, CD27hi, CD38hi) B-cells were determined by flow cytometry before and after vaccinations. Interferon-γ (IFN-γ) secreting T-cells were measured by elispot. Results: Patients who had been randomized to receive rituximab (n=14) or placebo (n=6) participated in this prospective study. Compared with placebo, fewer patients in the rituximab group achieved an adequate antibody response to S. pneumonia vaccine (21.4% versus 66.7%) or the Hib vaccine (28.6% versus 83.3%). These results correlated with a reduced bactericidal effect of anti-PRP antibodies observed in patients treated with rituximab compared with placebo (14.2% versus 83.3%). Two patients in the rituximab group demonstrated an adequate rise in antibody titer but with no functional bactericidal activity. In addition, 3 patients who did not mount an adequate antibody response, had IgG anti-PRP titers below protective levels and did not demonstrate bactericidal activity in vitro were considered Hib vaccine failures. There were no Hib vaccine failures in the placebo group. In the rituximab group, total number of B-cells declined rapidly after treatment (1.895 × 104/mL) relative to the placebo group (5.65 × 104/mL) and never fully recovered even 1 year post-treatment. Resting memory B-cells were significantly reduced after rituximab and remained at low levels even up to 1 year. Conversely, naïve B-cells recovered to near normal levels within 6 months of treatment. Activated pre-plasma B-cells increased following vaccination in the placebo group; yet, this response was variable in patients who had received rituximab. CD3+ T-cell numbers were unaffected by rituximab and vaccination; however, the number of IFN-γ- secreting T-cells were lower in the rituximab group. Conclusions: Rituximab treatment was associated with an impaired antibody response to vaccination, which in some patients was only demonstrated by impaired bactericidal activity. The expected increase in B-cell subsets was not observed following vaccination in the rituximab group, and T-cells, while normal in number, demonstrated functional impairments. Our findings characterize subtle defects in immunity which may persist after rituximab treatment. Disclosures: Off Label Use: Rituximab is not licensed for use with ITP patient. Kelton:Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffman-LaRoche: Research Funding. Arnold:Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffman-LaRoche: Research Funding.

scholarly journals Targeting BTN2A1 By a Unique Activating Mab Improves Vγ9Vδ2 T Cell Cytotoxicity Against Primary Acute Lymphoblastic Blasts

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2302-2302
Author(s):  
Anne-Charlotte Le Floch ◽  
Caroline Imbert ◽  
Aude De Gassart ◽  
Florence Orlanducci ◽  
Aude Le Roy ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Board Of Directors ◽  
Cell Lines ◽  
Research Funding ◽  
Leukemic Cells ◽  
Target Cells ◽  
Advisory Committees ◽  
Vγ9vδ2 T Cells ◽  
Privately Held

Abstract Introduction Vγ9Vδ2 T cells are new promising cytotoxic effectors in hematological malignancies. In acute myeloid leukemia and in non-Hodgkin lymphomas, Vγ9Vδ2 T cells-based immunotherapy has shown encouraging results both in preclinical models and in early phase clinical trials. Acute lymphoblastic leukemia (ALL) includes very heterogeneous clinico-biological entities, for which recent immunotherapy approaches are currently being developed. Nevertheless, global prognosis of ALL patients still be poor with a 5 years-overall survival of less than 40% and therefore, treatments need to be improved. Very few data are currently available on susceptibility of ALL blasts to Vγ9Vδ2 T cell cytotoxic activity. Vγ9Vδ2 T cells are activated by phosphoantigens bound to BTN3A1 on target cells. BTN3A molecules are targeted at clinical level, with the ICT01 agonist monoclonal antibody (mAb), that is currently tested in a multicentric phase ½ study (EVICTION study). Biology of Vγ9Vδ2 T cells has recently undergone a new paradigm with the identification of BTN2A1 as the direct ligand for Vγ9 chain of γδ TCR. BTN2A1 is mandatory for Vγ9Vδ2 T cell activation but its precise role in modulating functions of Vγ9Vδ2 T cells remains unknown. Here, we show that allogenic and autologous Vγ9Vδ2 T cells exert cytolytic functions against ALL cell lines and primary ALL blasts, and we report that Vγ9Vδ2 T cell cytotoxic activity is enhanced after treatment with a unique agonist mAb targeting BTN2A1. Material and methods 5 ALL cell lines (697, RS4;11, NALM-6, HPB-ALL, SUP-T1) and PBMC from 11 adults ALL patients at diagnosis (B-ALL, T-ALL and Ph+ ALL) were tested in functional assays. We evaluated apoptosis of ALL cell lines and of primary ALL blasts after coculture with allogenic Vγ9Vδ2 T cells. ALL samples were also tested for their expansion capacities and a degranulation assay was performed at D14. We assessed in parallel relative quantification of the level expression of BTN2A1 (ICT0302 and 7.48 epitopes), and BTN3A (20.1 and 108.5 epitopes) on surface of ALL blasts. DAUDI-BTN2AKO+2A1 and HEK293-BTN2AKO+2A1 cells were used in binding assays, and modulation of TCR binding was assessed using recombinant tetramerized Vγ9Vδ2 TCR. Results We showed that Vγ9Vδ2 T cells exert spontaneous cytotoxicity against ALL cell lines and primary ALL blasts with a heterogeneous susceptibility depending on the target. We demonstrated that anti-BTN2A1 ICT0302 agonist mAb significantly enhanced Vγ9Vδ2 T cells mediated apoptosis in comparison to control condition, even for the less spontaneously susceptible cells. We confirmed these observations with degranulation of autologous Vγ9Vδ2 T cells expanded from 5 ALL patients at diagnosis that was increased after treatment with anti-BTN2A1 ICT0302 agonist mAb. BTN3A and BTN2A1 were detected on surface of ALL blasts, and BTN3A 108.5 was the most expressed epitope. Interestingly, we observed that anti-BTN2A1 ICT0302 strongly increased binding of a recombinant Vγ9Vδ2 TCR to target cells using with HEK293 and DAUDI cells. Discussion Our results highlighted that Vγ9Vδ2 T cells exert cytolytic functions against ALL cells, both in allogenic and autologous setting and demonstrated that BTN2A1 targeting with our unique agonist mAb could potentiate effector activities of Vγ9Vδ2 T cells against ALL blasts. These results indicate that the sensitization of leukemic cells can be induced by activation BTN3A as well as BTN2A1 mAbs. These data bring novel understanding on the biology of BTN2A1 on leukemic cells and our ability to enhance both binding and function. These findings could be of great interest for the design of innovative Vγ9Vδ2 T cells-based immunotherapy strategies for treating ALL that could be extended to other cancer types. Disclosures De Gassart: ImCheck Therapeutics: Current Employment, Current holder of individual stocks in a privately-held company. Vey: Amgen: Honoraria; BMS: Honoraria; BIOKINESIS: Consultancy, Research Funding; NOVARTIS: Consultancy, Honoraria, Research Funding; SERVIER: Consultancy; JAZZ PHARMACEUTICALS: Honoraria; JANSSEN: Consultancy. Cano: ImCheck Therapeutics: Current Employment, Current holder of individual stocks in a privately-held company. Olive: Emergence Therapeutics: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Alderaan Biotechnology: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; ImCheck Therapeutics: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Anti-BTN2A1 ICT0302 is a murine agonist monoclonal antibody targeting BTN2A1 whose aim is to increase Vgamma9Vdelta2 T cells functions.

scholarly journals Off-the-Shelf, Multiplexed-Engineered iPSC-Derived NK Cells Mediate Potent Multi-Antigen Targeting of B-Cell Malignancies with Reduced Cytotoxicity Against Healthy B Cells

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 407-407
Author(s):  
Frank Cichocki ◽  
Jode P Goodridge ◽  
Ryan Bjordahl ◽  
Svetlana Gaidarova ◽  
Sajid Mahmood ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Nk Cells ◽  
Board Of Directors ◽  
Research Funding ◽  
Nk Cell ◽  
Advisory Committees ◽  
Car T Cells ◽  
Car T

Abstract Treatments for B-cell malignancies have improved over the past several decades with clinical application of the CD20-specific antibody rituximab and chimeric antigen receptor (CAR) T cells targeting CD19. Despite the success of these therapies, loss of CD20 after rituximab treatment has been reported in leukemia and lymphoma patients. Additionally, up to 50% of all patients receiving anti-CD19 CAR T-cell therapy relapse within the first year with many of those patients exhibiting CD19 loss. Thus, new therapeutic approaches are needed to address tumor antigen escape. Accordingly, we generated triple gene-modified iPSC-derived NK (iNK) cells, termed "iDuo" NK cells, tailored to facilitate multi-antigen targeting. The iPSC line was clonally engineered to express high-affinity, non-cleavable CD16a (hnCD16), an anti-CD19 CAR optimized for NK cell signaling, and a membrane-bound IL-15/IL-15R fusion (IL-15RF) molecule to enhance NK cell persistence (Fig. 1A). To model antigen escape, we generated CD19 knockout AHR77 lymphoma cells alongside wild type AHR77 cells (both CD20 +) as targets in cytotoxicity assays. Activated peripheral blood NK (PBNK) cells, non-transduced iNK cells, and iDuo NK cells were tested as effectors. Unlike PBNK cells or non-transduced iNK cells, iDuo NK cells efficiently eliminated wild type AHR77 cells with or without the addition of rituximab at all tested E:T ratios. Similarly, iDuo NK cells in combination with rituximab were uniquely able to efficiently eliminate CD19 KO AHR77 cells due to enhanced antibody-dependent cellular cytotoxicity (ADCC) driven by hnCD16 (Fig. 1B-E). Cytotoxicity mediated by iDuo NK cells was also evaluated using primary chronic lymphocytic leukemia (CLL) cells. Compared to expanded PBNK cells and non-transduced iNK cells, only iDuo NK cells (in the absence of rituximab) were able to kill primary CLL cells (Fig. 1F). Expression of IL-15RF by iDuo NK cells uniquely supports in vitro expansion without the need for cytokine supplementation. To determine whether IL-15RF supports in vivo persistence of iDuo NK cells, CD19 CAR iNK cells (lacking IL-15RF) and iDuo NK cells were injected into NSG mice without the addition of cytokines or CD19 antigen availability. iDuo NK cell numbers peaked within a week after injection and persisted at measurable levels for ~5 weeks, in marked contrast to CD19 CAR iNK cell numbers that were undetectable throughout (Fig. 1G). To evaluate the in vivo function of iDuo NK cells, NALM6 leukemia cells were engrafted into NSG mice. Groups of mice received tumor alone or were treated with 3 doses of thawed iDuo NK cells. iDuo NK cells alone were highly effective in this model as evidenced by complete survival of mice in the treatment group (Fig. 1H). To assess iDuo NK cells in a more aggressive model, Raji lymphoma cells were engrafted, and groups of mice received rituximab alone, iDuo NK cells alone, or iDuo NK cells plus rituximab. Mice given the combination of iDuo NK cells and rituximab provided extended survival compared to all other arms in the aggressive disseminated Raji lymphoma xenograft model (Fig. 1I). One disadvantage of anti-CD19 CAR T cells is their inability to discriminate between healthy and malignant B cells. Because NK cells express inhibitory receptors that enable "self" versus "non-self" discrimination, we reasoned that iDuo NK cells could have higher cytotoxicity against tumor cells relative to healthy B cells. To address this, we labeled Raji cells, CD19 + B cells from healthy donor peripheral blood mononuclear cells (PBMCs) and CD19 - PBMCs. Labeled populations of cells were co-cultured with iDuo NK cells, and specific killing was analyzed. As expected, iDuo NK cells did not target CD19 - PBMCs. Intriguingly, iDuo NK cells had much higher cytotoxic activity against Raji cells compared to primary CD19 + B cells, suggesting a preferential targeting of malignant B cells compared to healthy B cells. Together, these results demonstrate the potent multi-antigen targeting capability and in vivo antitumor function of iDuo NK cells. Further, these data suggest that iDuo NK cells may have an additional advantage over anti-CD19 CAR T cells by discriminating between healthy and malignant B cells. The first iDuo NK cell, FT596, is currently being tested in a Phase I clinical trial (NCT04245722) for the treatment of B-cell lymphoma. Figure 1 Figure 1. Disclosures Cichocki: Gamida Cell: Research Funding; Fate Therapeutics, Inc: Patents & Royalties, Research Funding. Bjordahl: Fate Therapeutics: Current Employment. Gaidarova: Fate Therapeutics, Inc: Current Employment. Abujarour: Fate Therapeutics, Inc.: Current Employment. Rogers: Fate Therapeutics, Inc: Current Employment. Huffman: Fate Therapeutics, Inc: Current Employment. Lee: Fate Therapeutics, Inc: Current Employment. Szabo: Fate Therapeutics, Inc: Current Employment. Wong: BMS: Current equity holder in publicly-traded company; Fate Therapeutics, Inc: Current Employment. Cooley: Fate Therapeutics, Inc: Current Employment. Valamehr: Fate Therapeutics, Inc.: Current Employment. Miller: Magenta: Membership on an entity's Board of Directors or advisory committees; ONK Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Vycellix: Consultancy; GT Biopharma: Consultancy, Patents & Royalties, Research Funding; Fate Therapeutics, Inc: Consultancy, Patents & Royalties, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Wugen: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Bone Marrow Hematopoietic Dysfunction in Untreated Chronic Lymphocytic Leukemia Is Partially Mediated By Exposure to Constituents of the Leukemic Microenvironment

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3132-3132
Author(s):  
Bryce Manso ◽  
Kimberly Gwin ◽  
Charla R Secreto ◽  
Henan Zhang ◽  
Wei Ding ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Board Of Directors ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Healthy Controls ◽  
Advisory Committees ◽  
The Impact

Abstract Peripheral immune dysfunction in B-Chronic Lymphocytic Leukemia (CLL) is well-studied and likely relates to the incidence of serious recurrent infections and second malignancies that plague CLL patients. However, the current paradigms of known immune abnormalities are not able to consistently explain these complications and it is not easy to correct CLL patient immune status. Here, we expand on our preliminary reports that demonstrate bone marrow (BM) hematopoietic dysfunction in early and late stage untreated CLL patients. We found reduced short-term functional capacity of hematopoietic progenitors in BM using colony forming unit assays (Figure 1A-C) and flow cytometry revealed significant reductions in frequencies of hematopoietic stem and progenitor cell (HSPC) populations (exemplified by Lin-CD34+ HSPCs, Figure 1D). We further report that protein levels of the transcriptional regulators HIF-1α, GATA-1, PU.1, and GATA-2 are overexpressed in distinct HSPC subsets from CLL patient BM, providing molecular insight into the basis of HSPC dysfunction. Interestingly, sustained myelopoiesis, evaluated by limiting dilution analysis in long-term culture-initiating cell (LTC-IC) assays maintained for five weeks, revealed no difference between healthy controls and CLL patients. These new data indicate that when HSPCs are removed from the leukemic microenvironment for ample in vitro culture time, they recover the ability to sustain myelopoiesis. To further assess the impact of the CLL microenvironment on HSPC biology, isolated HSPCs (CD34+ BM cells) from healthy controls were exposed in vitro to known leukemic microenvironment constituents. Exposure to TNFα, a cytokine constitutively produced by CLL B cells, resulted in rapid increases in PU.1 and GATA-2 proteins (Figure 2A-D). Similarly, addition of TNFα to the LTC-IC assay resulted in a striking ablation of myelopoiesis, even at the highest input cell concentration. Further, overexpression of PU.1 and GATA-2 were observed in HSPCs following co-culture with CLL B cells, a result that was not recapitulated when cells were exposed to IL-10, another cytokine constitutively produced by CLL B cells. These findings indicate specific components of the leukemic microenvironment are involved in HSPC modulation. Together, these findings expand on our previous observations of BM hematopoietic dysfunction in untreated CLL patients and offer new molecular insights into the contribution of the leukemic microenvironment on immunodeficiency in CLL. Disclosures Ding: Merck: Research Funding. Parikh:Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; Janssen: Research Funding; Abbvie: Honoraria, Research Funding; Gilead: Honoraria; AstraZeneca: Honoraria, Research Funding. Kay:Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding.

scholarly journals Indoleamine 2,3-Dioxygenase Mediates Survival of Chronic Lymphocytic Leukemia B Cells through Aryl Hydrocarbon Receptor By Inducing Mcl1

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 19-19
Author(s):  
Claudio Giacinto Atene ◽  
Rossana Maffei ◽  
Stefania Fiorcari ◽  
Silvia Martinelli ◽  
Patrizia Zucchini ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Aryl Hydrocarbon Receptor ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Strong Increase ◽  
Indoleamine 2,3 Dioxygenase ◽  
Aryl Hydrocarbon

Introduction: Chronic lymphocytic leukemia (CLL) is a dynamic disease in which monoclonal B cells proliferate within the pseudo-follicular centers in lymphoid organs and then they accumulate due to an intrinsic defect of apoptosis. Leukemic cells are considered as "addicted to the host" since extrinsic signals from the microenvironment strongly influence the establishment of a progressive immunosuppression for malignant cell growth and survival. The cytoplasmic enzyme indoleamine 2,3-dioxygenase (IDO) mediates the conversion of the essential amino acid tryptophan (Trp) into metabolic byproducts such as kynurenine (Kyn). Kyn and other secondary metabolites are endogenous activators of the aryl hydrocarbon receptor (AHR), a ligand-controlled transcription factor that mediates cellular responses to toxins or endogenous ligands. The IDO-Kyn-AHR axis plays important roles in carcinogenesis and cancer progression. The mechanisms that promote inflammation around tumor tissues and determine immune tolerance consist in Trp depletion, which induces T cell apoptosis, and in Kyn-mediated AHR activation that inhibits effector T cells and promotes regulatory T cells differentiation. IDO protein is expressed in human hematologic malignancies and its level is correlated with a poor prognosis and chemoresistance. The IDO activity, measured as the Kyn/Trp ratio, was reported to be increased in CLL cases comparing to normal controls. Aim: We wondered to characterize the expression of IDO and AHR in CLL patients and to dissect the biological function of the IDO-Kyn-AHR axis. Methods: Gene transcription and protein expression were evaluated by real time PCR and western blot. Enzymatic activity was assessed through ELISA. Survival was measured with PI/annexin V assay. Overexpression and silencing of target genes was obtained by nucleofection. Results: Firstly, we observed that CLL cells expressed both IDO and AHR at variable levels. Moreover, we found that several microenvironmental signals such as IFNγ, LPS, anti-IgM, CpG oligo DNA, CD40L and TNFα were able to up-regulate IDO and AHR mRNA and protein. To characterize the pathways able to mediate IDO expression, we stimulated CLL cells with IFNγ and CD40L. Using ruxolitinib, an inhibitor of JAK-STAT pathway, we found that IFNγ induced IDO through STAT1 signaling. Again, CD40L stimulation determined IDO overexpression through the non-canonical NF-kB pathway, as assessed by treating cells with NF-κB inducing kinase inhibitor, NIK SMI1. We also confirmed that IFNγ-treated CLL cells were able to produce a functional IDO enzyme by measuring Kyn production and Trp consumption by ELISA. The strong increase in the Kyn/Trp ratio induced by IFNγ was significantly reduced by ruxolitinib treatment. To verify if Kyn produced by CLL cells could act through an autocrine loop on AHR, leukemic cells were treated with Kyn. We observed that Kyn mediated AHR translocation from the cytoplasm to the nuclei, inducing its activation as assessed by up-regulation of CYP1A1, a known AHR target gene. Of interest, we found that Kyn treatment improved CLL cells survival. Analyzing the anti-apoptotic proteins of the Bcl2 family after Kyn treatment, we found the induction of Mcl1, that was affected by adding CH-223191, an antagonist of AHR. Moreover, we transfected CLL cells with an IDO vector. The up-regulation of IDO increased CLL cells survival through the induction of Mcl1. Accordingly, when CLL cells were silenced for AHR, we observed a reduction of their survival. Conclusion: Our data demonstrate the constitutive expression of IDO and AHR in CLL cells. Furthermore, the tumor microenvironment promotes the induction of IDO and AHR through a complex signaling crosstalk with leukemic cells. Our findings underline that IDO-Kyn-AHR axis is active in CLL cells and promotes Mcl1 expression, sustaining the survival of CLL cells. Disclosures Luppi: Gilead Sci: Consultancy, Speakers Bureau; MSD: Consultancy; Sanofi: Consultancy; Abbvie: Consultancy; Daiichi-Sankyo: Consultancy; Novartis: Consultancy, Speakers Bureau. Marasca:Gilead Sci: Honoraria, Research Funding; Roche: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Janssen: Honoraria, Research Funding; Abbvie: Consultancy, Honoraria.

Sign in / Sign up

Export Citation Format

Share Document