scholarly journals Cyclin-A1 represents a new immunogenic targetable antigen expressed in acute myeloid leukemia stem cells with characteristics of a cancer-testis antigen

Blood ◽  
2012 ◽  
Vol 119 (23) ◽  
pp. 5492-5501 ◽  
Author(s):  
Sebastian Ochsenreither ◽  
Ravindra Majeti ◽  
Thomas Schmitt ◽  
Derek Stirewalt ◽  
Ulrich Keilholz ◽  
...  
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Myeloid Leukemia ◽  
High Expression ◽  
Target Cells ◽  
Cyclin A1 ◽  
Peripheral Tissues ◽  
Acute Myeloid

Abstract Targeted T-cell therapy is a potentially less toxic strategy than allogeneic stem cell transplantation for providing a cytotoxic antileukemic response to eliminate leukemic stem cells (LSCs) in acute myeloid leukemia (AML). However, this strategy requires identification of leukemia-associated antigens that are immunogenic and exhibit selective high expression in AML LSCs. Using microarray expression analysis of LSCs, hematopoietic cell subpopulations, and peripheral tissues to screen for candidate antigens, cyclin-A1 was identified as a candidate gene. Cyclin-A1 promotes cell proliferation and survival, has been shown to be leukemogenic in mice, is detected in LSCs of more than 50% of AML patients, and is minimally expressed in normal tissues with exception of testis. Using dendritic cells pulsed with a cyclin-A1 peptide library, we generated T cells against several cyclin-A1 oligopeptides. Two HLA A*0201-restricted epitopes were further characterized, and specific CD8 T-cell clones recognized both peptide-pulsed target cells and the HLA A*0201-positive AML line THP-1, which expresses cyclin-A1. Furthermore, cyclin-A1–specific CD8 T cells lysed primary AML cells. Thus, cyclin-A1 is the first prototypic leukemia-testis-antigen to be expressed in AML LSCs. The pro-oncogenic activity, high expression levels, and multitude of immunogenic epitopes make it a viable target for pursuing T cell–based therapy approaches.

scholarly journals L4 Synthetic agonistic receptor-activating BiTEs – a modular platform for the efficient targeting of acute myeloid leukemia

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A2.2-A3
Author(s):  
M Benmebarek ◽  
BL Cadilha ◽  
M Hermann ◽  
S Lesch ◽  
C Augsburger ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
T Cell Activation ◽  
Tumour Cell ◽  
Myeloid Leukemia ◽  
Cell Activation ◽  
Cell Lysis ◽  
Target Cells ◽  
Acute Myeloid

BackgroundTargeted immunotherapies have shown limited success in the context of acute myeloid leukemia (AML). Due to the mutational landscape and heterogeneity attributed to this malignancy and toxicities associated with the targeting of myeloid lineage antigens, it has become apparent that a modular and controllable cell therapy approach with the potential to target multiple antigens is required. We propose a controlled ACT approach, where T cells are armed with synthetic agonistic receptors (SARs) that are conditionally activated only in the presence of a target AML-associated antigen, and a cross-linking bispecific T cell engager (BiTE) specific for both (SAR) T cell and tumour cell.Materials and MethodsA SAR composed of an extracellular EGFRvIII, trans-membrane CD28, and intracellular CD28 and CD3z domains was fused via overlap-extension PCR cloning. T cells were retrovirally transduced to stably express our SAR construct. SAR-specific bispecific T cell engagers (BiTE) that target AML-associated antigens were designed and expressed in Expi293FTMcells and purified by nickel affinity and size exclusion chromatography (SEC). We validated our approach in three human cancer models and patient-derived AML blasts expressing our AML-associated target antigen CD33.ResultsCD33-EGFRvIII BiTE, monovalently selective for our SAR, induced conditional antigen-dependent activation, proliferation and differentiation of SAR-T cells. Further, SAR T cells bridged to their target cells by BiTE could form functional immunological synapses, resulting in efficient tumor cell lysis with specificity towards CD33-expressing AML cells. SAR.BiTE combination could also mediate specific cytotoxicity against patient-derived AML blasts whilst driving SAR T cell activation. In vivo, treatment with SAR.BiTE combination could efficiently eradicate leukemia and enhance survival in an AML xenograft model. Furthermore, we could show selective activation of SAR T cells, as well as a controllable reversibility of said activation upon depletion of the T cell engaging molecule.ConclusionsHere we apply the SAR x BiAb approach in efforts to deliver specific and conditional activation of agonistic receptor-transduced T cells, and targeted tumour cell lysis. The modularity of our platform will allow for a multi-targeting ACT approach with the potential to translate the ACT successes of B cell malignancies to AML. With a lack of truly specific AML antigens, it is invaluable that this approach possesses an intrinsic safety switch via its BiTE facet. Moreover, we are able to circumvent pan-T cell activation due to the specific targeting and activation of SAR T cells.Disclosure InformationM. Benmebarek: None. B.L. Cadilha: None. M. Hermann: None. S. Lesch: None. C. Augsburger: None. B. Brauchle: None. S. Stoiber: None. A. Darwich: None. F. Rataj: None. C. Klein: A. Employment (full or part-time); Significant; Roche. K. Hopfner: None. M. Subklewe: None. S. Endres: None. S. Kobold: None.

scholarly journals Multi-Antigen Primed T Cells Promote Apoptosis of Acute Myeloid Leukemia (AML)

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4794-4794
Author(s):  
Ebtesam Nafie ◽  
Mathias Oelke ◽  
Melissa Valerio ◽  
Sojung Kim ◽  
Ivan Rodriguez ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
Time Dependent ◽  
Target Cells ◽  
Ifn Γ ◽  
Acute Myeloid

Abstract Introduction Acute myeloid leukemia (AML), the most common acute leukemia in adults, is characterized by uncontrolled proliferation of immuature myeloid cells. Despite newly approved drugs, AML remains largely incurable due to the persistence of the leukemia stem cell (LSC) population which lie quiescent in the bone marrow niche. Immunotherapy has potential to eradicate LSCs, however, no unique LSC immunophenotype has been identified. Moreover, it is necessary to simultaneously target multiple antigens (Ags) to prevent immune escape and to overcome refractory disease. We present in vitro studies in support of a therapeutic platform capable of targeting multiple intracellular Ags which could meet this challenge. The adoptive transfer of activated T cells primed to engage diverse AML associated epitopes by ex vivo exposure to artificial Ag presenting cells (aAPC) has the potential to eliminate both primary leukemia blasts and LSCs. Hypothesis Ex vivo enrichment and expansion (E+E) of antigen-educated CD8+ T cells recognizing 5 peptides derived from 3 proteins, Cyclin A1, PRAME and WT1, can selectively identify, engage, and kill AML cell lines or patient-derived (PD) AML blasts in a HLA A*02:01 restricted manner in vitro. Materials and Methods T cells from the peripheral blood mononuclear cell fraction of a healthy HLA A*02:01 donor were enriched for antigen-educated CD8+/CD4 -T cells. These cells were cultured with nanoparticles decorated with the 5 peptides and a costimulatory protein, resulting in the activation and expansion of those T cells expressing the cognate T cell receptors. These cells are composed of ~97% abT cells, 3% gdT cells and ~13% T scm, 41.5% T cm, 39.5%T em, 6%T emra and 1% T n. Results Ex vivo expanded educated T cells exhibit target-specific anti-AML activity. T cell mediated cell apoptosis of HLA-matched THP1 cells is dose and time-dependent. At 10:1 effector to target (E:T) ratio, ~28% apoptosis occurred at 24 hrs, while apoptosis was at basal levels when antigen non-educated T cells were used (data not shown). Studies were extended to PD AML cells (Fig. 1A: 012; Fig. 1B: 415) where antigen educated T cells elicited rapid (<16 hrs) and extensive (~90%) apoptosis of target PD AML cells at all E:T ratios examined. Time lapse photography of T cell/PD AML incubations revealed antigen-educated T cells clustered around AML cells (Fig. 2A), a fraction of the latter disappearing over the course of 12 hrs while PD AML cells incubated with non-educated T cells (Fig. 2B) remained viable over 12 hrs. Furthermore, there is little or no T cell movement or clustering in the wells with unprimed, non-active T cells. Release of IFN-γ by educated T cells. T cells (Fig.3A: antigen-educated through E+E) were incubated at E:T::5:1 for 24 to 48 hrs and IFN-γ in supernatants measured. The fold difference over non-educated T cells incubated with AML cells for the same time is shown and can reach over 5-fold. IFN-γ accumulation was time-dependent where antigen-educated T cells were combined with HLA-A2 matched THP1 or PD AML cells (012, 415, 470). Educated T cells were not active against target cells lacking HLA-A2 (K562) demonstrating HLA restricted killing (Fig. 3B). Additionally, antigen-educated T cells incubated without any target released slightly more IFN-γ than non-educated T cells under similar conditions but AML cells fail to stimulate IFN-γ release from non-educated T cells (data not shown). Conclusions We demonstrate HLA restricted cytotoxic activity of antigen-educated T cells against THP1 AML cells and PD AML blasts as shown by flow cytometry and microscopy. Consistent with target cell death, the supernatants from assays with antigen-educated T cells and HLA A*02:01 AML target cells exhibited over 5-fold more IFN-γ than media from assays of non-educated cells under identical conditions. Under these in vitro conditions, PD AML blasts were more readily killed than THP1 cells perhaps due to higher target antigen density (data not shown). These results support the use of multi-antigen-educated T cells for adoptive transfer to treat AML. To investigate the safety and establish the recommended phase II dose, a multi-center Phase I clinical study is underway in relapsed AML post-allo-HCT (NCT 04284228). Future studies will incorporate new antigens to enable broader targeting of a heterogeneous population of AML within and across patients Figure 1 Figure 1. Disclosures Oelke: Neximmune, Inc: Current Employment. Kim: Neximmune, Inc: Current Employment. Marcucci: Agios: Other: Speaker and advisory scientific board meetings; Novartis: Other: Speaker and advisory scientific board meetings; Abbvie: Other: Speaker and advisory scientific board meetings. Al Malki: Jazz Pharmaceuticals, Inc.: Consultancy; Hansa Biopharma: Consultancy; Neximmune: Consultancy; CareDx: Consultancy; Rigel Pharma: Consultancy.

scholarly journals Identification and Isolation of Tumor-Specific Cytotoxic T Lymphocytes in Acute Myeloid Leukemia Patients through the Identification of T-Cells Capable to Establish Stable Interactions with Leukemic Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3336-3336
Author(s):  
Estefania Garcia-Guerrero ◽  
Luis I. Sanchez-Abarca ◽  
Esther Domingo ◽  
Teresa Ramos ◽  
Jose Antonio Bejarano-García ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
T Lymphocytes ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Myeloid Leukemia ◽  
Target Cells ◽  
Acute Myeloid

Abstract Introduction Autologous adoptive T cell therapies, based on the use of tumor infiltrating lymphocytes (TILs), have made great progress in recent years for the treatment of solid tumors, especially melanoma. However, further work is needed to isolate tumor-reactive T cells among patients diagnosed with hematologic malignancies. The dynamics of the interaction between T cells and antigen presenting cells (APC) dictate the quality of the immune responses. While stable joints between target cells and T lymphocytes lead to the induction of T cell activation and immune response, brief contacts contribute to the induction of immune-tolerance. Taking advantage of the strong interaction between target cell and activated T-cells, we show the feasibility to identify and isolate tumor-specific cytotoxic T lymphocytes (CTLs) from acute myeloid leukemia (AML) patients. Using this approach, CTLs stably bound through T cell receptor to tumor cells (doublet forming T-cells) can be identified in peripheral blood and bone marrow and subsequently selected and isolated by FACS-based cell sorting. Methods Co-cultures between PBMC from AML patients in complete remission and AML tumor cells (PKH-stained) from the same patient were performed to study the percentage of doublet-forming T cells (CD3+PKH+) (T cell bound to a tumor cell). After 15 hours of co-culture, cells were stained and sorted. Secondary co-cultures with autologous tumor cells (used in primary co-culture) were performed to study the cytotoxic activity and cytokine production of T-cells capable or not to form stable joints with the leukemic cells (doublet population vs non-doublet population). Results Doublet-forming T cells from AML patients were identified in a range of 2% to 6% (mean=3.83%, n=5). Immunophenotyping analysis showed differences between doublet-forming T cells (CD3+PKH+) and those T cells which did not form stable and strong interactions with target cells (CD3+PKH-). Doublet T cells displayed a higher percentage of CD8+ T cells and higher percentage of effector CD4+ and CD8+ T cells compared to non-doublet T cells. Next, we explored, among effector CD4+ and CD8+ cells, those with cytotoxic phenotype. As expected, a high percentage of effector CD8+ doublet T cells showed Granzyme B and perforin expression, thus corresponding with a cytotoxic immune-phenotype (n=3, mean 65.51%). Within effector CD4+ doublet T cells, a mean of 9.053 % showed expression of both Granzyme B and perforin corresponding with CD4+ CTL (n=3). Regarding CD57 and CD16 markers, a mean of 18.62% of effector CD4+ doublet T cells were positive for both markers, compared to 65.84% of effector CD8+ doublet T cells (n=3). Further, we performed secondary co-cultures to analyze the CD69 activation marker after 24h of co-culture. A high percentage of CD69+ cells was observed in co-cultures with doublet-forming T cells against target cells as compared to non-doublet T cells (n=3, p=0.0053). Finally, analysis of supernatants of co-culture of doublet T cells and non-doublet T cells with target cells revealed specific secretion of IFNγ and IL-2 (n=3, p=0.0001; p=0.0005, respectively). The cytolytic activity was evaluated comparing the viability of tumor cells cultured alone or with doublet-forming T cells or non-doublet T cells from the same patient. A significant increase of the specific lysis of AML cells was observed when doublet T cells were co-cultured as compared to non-doublet T cells (p=0.0424, n=5). This encouraged us to examine whether we were able to identify doublet-forming T cells from bone marrow of AML patients at diagnosis. Analyses of bone marrow by flow cytometry reveled a small percentage of CD3+CD34+ population corresponding with bone marrow-doublet-forming T cells (n=3, mean=2.9%). Interestingly, bone marrow-doublet-forming T cells show a higher percentage of CD4+ T cells, whereas bone marrow-non-doublet T cells show a higher percentage of CD8+ T cells. Conclusions Our data demonstrate that when T cells from AML patients are co-cultured with tumor cells, a "doublet T cell" population appears. This population consists of T cells capable to bind tumor cells. These CTLs display higher percentage of effector cells and a marked cytotoxic activity against AML blasts. In conclusion, we have developed a new procedure to identify and select specific cytotoxic T cells in both bone marrow and peripheral blood from patients diagnosed with acute myeloid leukemia. Figure. Figure. Disclosures Sanchez-Abarca: Virgen del Rocio University Hospital: Patents & Royalties. Ramos:Takeda Oncology: Research Funding.

The Genotype of T-Cell Costimulatory Molecule Is Associated with Relapse Incidence In Patients with Acute Myeloid Leukemia After Allogeneic Hematopoietic Cell Transplantation

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 684-684
Author(s):  
Haowen Xiao ◽  
Xiaoyu Lai ◽  
Yi Luo ◽  
Jimin Shi ◽  
Yamin Tan ◽  
...  
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Myeloid Leukemia ◽  
Costimulatory Molecule ◽  
Leukemia Relapse ◽  
The Media ◽  
Risk Of Relapse ◽  
Acute Myeloid

Abstract Abstract 684 Background: Disease relapse is one of the leading causes of death following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Donor T lymphocytes play a critical role in alloimmune recognition and their ability to detect non-self-antigens can lead to graft-versus-host disease (GVHD) or contribute to relapse prevention through recognition and elimination of minimal residual disease. CD28 is the primary T-cell costimulatory molecule constitutively expressed on the majority of T cells. Upon interaction with its ligands B7, CD28 transduces a signal that enhances the activation and proliferation of T cells. Another member of the CD28 family is inducible co-stimulator (ICOS). Although not constitutively expressed, ICOS is rapidly upregulated on T lymphocytes upon activation. Cytotoxic T-lymphocyte antigen 4 (CTLA-4), a homologous molecule of CD28, is a key factor in regulating and maintaining self-tolerance, providing a negative signal to T cells. Although several single-nucleotide polymorphisms (SNPs) within those costimulatory molecule genes have been identified to be associated with the risk of autoimmune disease, their association with outcome after allo-HSCT has yet to be explored. This present study was designed to investigate the influence of CD28, ICOS and CTLA-4 genes polymorphisms on the outcome of patients with acute myeloid leukemia (AML) after allo-HSCT. Methods: The entire study population consisted of 86 consecutive AML patients and their donors who were transplanted from 2001 to 2009 in our Unit. Genomic DNA was extracted from peripheral blood samples obtained from recipients and donors before transplantation. Five SNPs of CD28 -594(A/G), ICOS -693(G/A) and CTLA-4 -1722(A/G), +49(A/G) and CT60(A/G) were analyzed. Results: (1) The media age of the patients was 27 years (range, 12–49 years). At the time of transplantation, 70 patients were in first complete remission (CR), 10 patients in second CR, 3 patients in third CR and 3 patients in progressive status. 33 patients underwent HLA-matched sibling HSCT and 53 patients underwent unrelated HSCT. All patients received myeloablative conditioning based on busulfan/cyclophosphamide (BuCy) without total body irradiation (TBI). The GVHD prophylaxis is consisted of cyclosporin A, a short-term methotrexate and mycophenolate mofetil. (2) Only one patient experienced engraftment failure. 18(20.9%), 20(23.3%) and 3(3.5%) patients respectively developed grade I, II and severe acute GVHD (aGVHD). 16(18.6%) and 15(17.4%) patients developed limited and extensive chronic GVHD (cGVHD). (3) 17 patients (19.8%) experienced relapse, the media time was 15.6 months after allo-HSCT (range, 2–24 months). (4) Patients receiving stem cells from a donor with AA genotype in position +49 or CT60 of CTLA-4 gene relapsed more frequently than those with AG/GG genotypes (for +49: 50% vs 14.1%, P=0.012; for CT60: 80% vs 16%, P<0.0001). (5) Patients receiving stem cells from a donor with CD28 -594 AA genotype had a lower incidence of relapse than those with other genotypes (0 vs 25%, P=0.04), due to a higher incidence of aGVHD (83.3% vs 38.2%, P=0.004). (6) In multivariate analysis, donor with CTLA-4 CT60 AA genotype (RR=13.411, 95%CI: 3.808–47.233, P<0.0001), and absence of cGVHD (RR=2.12, 95%CI: 1.112–4.042, P=0.022) were found to significantly contribute to the risk of relapse after allo-HSCT. Furthermore, patients receiving CTLA-4 CT60 AA genotype donor had worse overall survival at 7 years (20% vs 77.8%, RR=10, 95%CI: 3.761–16.239, P<0.0001). The polymorphic sites CTLA-4 -1722 and ICOS -693 did not correlate with the risk of relapse. Nor did patient 5 polymorphic sites genotype. Conclusions: These results, which is the first report of T-cell costimulatory molecule genes polymorphic features with the risk of leukemia relapse in AML patients after allo-HSCT, suggest an interaction between donor CTLA-4 CT60 AA genotype and the risk of relapse. The CTLA-4 CT60 AA genotype has been reported to increase the production of soluble form of CTLA-4, suggesting that increased expression of CTLA-4 would be associated with a decrease ability of the immune system to detect and eliminate tumor associated antigens. According to our results, anti-CTLA-4 antibodies may be a promising therapeutic strategy in leukemia relapse after allo-HSCT at least in patients receiving CTLA-4 CT60 AA genotype donor. Disclosures: No relevant conflicts of interest to declare.

Chimeric Antigen Receptor for Specific Targeting of Acute Myeloid Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4225-4225
Author(s):  
Irene Pizzitola ◽  
Fernando Anjos-Afonso ◽  
Kevin Rouault-Pierre ◽  
Francois Lassailly ◽  
Sarah Tettamanti ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Cord Blood ◽  
Myeloid Leukemia ◽  
Genetically Modified ◽  
Target Cells ◽  
Cik Cells ◽  
Acute Myeloid

Abstract Abstract 4225 Despite the progress in the treatment of acute myeloid leukemia (AML) achieved in the last decades, a significant number of patients are still refractory to or relapse after conventional chemotherapy regimens. Therefore it is necessary to develop novel alternative approaches. Immunotherapy with T cells genetically modified to express chimeric antigen receptors (CARs) represent a valid option in this sense. CARs are artificial T-cell receptors constituted by a specific antigen-binding domain, and a signaling region, that, upon antigen recognition, leads to T-cell activation, and lysis of the target cells. AML is a potential optimal target for CAR strategy because of the over-expression of a number of surface antigens like CD33, CD123. Since CD33 is also expressed on normal hematopoietic stem/progenitors cells (HSPCs) resulting in a potential severe impairment of normal myelopoiesis, CD123 has recently emerged as new potential attractive molecules based on its differential expression pattern, being still wildly overexpressed by AML population, and at the same time less expressed on HSPCs. Here we describe the in vivo efficacy and the safety of this approach based on Cytokine-Induced-Killers (CIK) cells genetically modified to express CAR molecules specific for the CD33 or CD123 antigen. Once injected into low-level AML engrafted NSG mice (median of hCD45+CD33+ 0.6% before treatment), genetically modify T cells had a potent antitumor effect. Indeed, the bone marrow of control untreated animals or mice treated with un-manipulated CIK cells, was infiltrated by leukemic cells (86% and 81% leukemic engraftment), while in 7/8 anti-CD33-CD28-OX40-ζ and 8/10 anti-CD123-CD28-OX40-ζ treated mice we couldn't detect any AML cells. Similar results have been obtained when the treatment via T cell injection start when high AML burden has been obtained (median of hCD45+CD33+ 70% before treatment). One week after the last CIK's injection the level of AML engraftment was 96%, 87%, 0.35% and 0.34% for untreated mice, mice treated with un-manipulated CIK cells and with anti-CD33-CD28-OX40-ζ and anti-CD123-CD28-OX40-ζ transduced CIK-cells respectively. We performed secondary transplantation on the residual AML cells present in these animals and mice were treated again with transduced CIK cells. Residual AML cells were still sensitive to CARs approach, leading once again to an almost complete eradication of the disease (median level of hCD45+CD33+ engraftment was 98%, 0.02% and 0.04% respectively for untreated mice, anti-CD33-CD28-OX40-ζ and anti-CD123-CD28-OX40-ζ transduced CIK-cells). Furthermore, a fundamental issue was to determine the safety profile of such approach against normal hematopoietic precursors. In untreated mice injected with primary cord blood derived CD34+ cells the level of engraftment of hCD45 compartment was 42% whilst in mice treated with un-manipulated, anti-CD33-CD28-OX40-ζ or anti-CD123-CD28-OX40-ζ transduced CIK-cells the levels of human compartment was 40%, 11.7% and 26.3% respectively. Moreover when we consider specifically the CD34+CD38- compartment, enriched in HSC, the level of engraftment was 1.92%, 1.02%, 0.55% and 0.83%. Secondary transplantations are now ongoing to give a more complete profile about the remaining HSC repopulating capability after treatment. To more closely mimic a physiological context, similar experiments are ongoing using mice engrafted with normal adult bone marrow instead of umbilical cord blood. These experiments should offer relevant information concerning the efficacy and safety of the proposed strategy particularly in the context of minimal residual disease in high-risk transplanted AML patients. Moreover CAR approach could be potentially used to treat patients resistant to conventional chemotherapeutic approaches or for whom high dose chemotherapy treatment could not be proposed. Disclosures: No relevant conflicts of interest to declare.

Cyclin-A1 expression in acute myeloid leukemia stem cells and its representation as an immunogenic antigen that can be targeted by cytotoxic T cells.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 2523-2523
Author(s):  
Sebastian Ochsenreither ◽  
Ravindra Majeti ◽  
Keith Loeb ◽  
Derek L. Stirewalt ◽  
Ulrich Keilholz ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Stem Cell ◽  
T Cell ◽  
Myeloid Leukemia ◽  
Peptide Library ◽  
Cyclin A1 ◽  
T Cell Clones ◽  
Cell Clones ◽  
Acute Myeloid

2523 Background: Targeted T-cell therapy represents a more specific and less toxic alternative to allogeneic stem cell transplantation for providing a cytotoxic anti-leukemic response to eliminate the leukemic stem cell (LSC) compartment in acute myeloid leukemia (AML). The aim of this study was to identify a leukemia-associated antigen that is both immunogenic and exhibits selective high expression in AML LSCs. Methods: Expression microarrays of leukemic and normal cells were used to identify suitable candidate genes. Cyclin-A1 appeared to be differentially expressed, and was further analyzed by quantitative RT-PCR, intracellular FACS staining, and immunofluorescence microscopy. T-cell clones specific for cyclin-A1 were generated by stimulation in vitro with an overlapping peptide library, followed by cloning of responding cells. Specificity of the clones was documented by intracellular IFNg and tetramer staining. Cytotoxicity was determined by chromium release and caspase-3 cleavage assays. Results: To identify target candidates with a suitable expression pattern, microarray data from LSCs, hematopoietic cells and healthy tissues were compared. Cyclin-A1 was found to be selectively expressed in LSCs of >50% of AML patients, but minimally expressed in normal tissues with exception of testis. Using dendritic cells and monocytes pulsed with a cyclin-A1 peptide library, T-cells were generated against eight cyclin-A1 oligopeptides. Two HLA A2-restricted epitopes were further characterized, and specific T-cell clones recognized both peptide-pulsed target cells and the HLA A2-positive AML line THP-1. Furthermore, cyclin-A1-specific CD8 T-cells lysed primary AML cells. Conclusions: Cyclin-A1, known to be important in meiosis, is expressed in AML LSCs and testis and can be targeted by T-cells. Thus, cyclin-A1 is the first prototypic LSC-associated leukemia-testis-antigen. Cyclin-A1 already has been shown to be leukemogenic in mice and to promote proliferation and survival in AML blasts. This pro-oncogenic activity, together with high expression levels and a multitude of immunogenic epitopes, make it a promising target for T-cell based therapy approaches.

scholarly journals A modular and controllable T cell therapy platform for acute myeloid leukemia

Leukemia ◽  
2021 ◽  
Author(s):  
Mohamed-Reda Benmebarek ◽  
Bruno L. Cadilha ◽  
Monika Herrmann ◽  
Stefanie Lesch ◽  
Saskia Schmitt ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Cell Therapy ◽  
Myeloid Leukemia ◽  
Tumor Antigens ◽  
Adoptive T Cell Therapy ◽  
Single Chain ◽  
T Cell Therapy ◽  
Acute Myeloid

AbstractTargeted T cell therapy is highly effective in disease settings where tumor antigens are uniformly expressed on malignant cells and where off-tumor on-target-associated toxicity is manageable. Although acute myeloid leukemia (AML) has in principle been shown to be a T cell-sensitive disease by the graft-versus-leukemia activity of allogeneic stem cell transplantation, T cell therapy has so far failed in this setting. This is largely due to the lack of target structures both sufficiently selective and uniformly expressed on AML, causing unacceptable myeloid cell toxicity. To address this, we developed a modular and controllable MHC-unrestricted adoptive T cell therapy platform tailored to AML. This platform combines synthetic agonistic receptor (SAR) -transduced T cells with AML-targeting tandem single chain variable fragment (scFv) constructs. Construct exchange allows SAR T cells to be redirected toward alternative targets, a process enabled by the short half-life and controllability of these antibody fragments. Combining SAR-transduced T cells with the scFv constructs resulted in selective killing of CD33+ and CD123+ AML cell lines, as well as of patient-derived AML blasts. Durable responses and persistence of SAR-transduced T cells could also be demonstrated in AML xenograft models. Together these results warrant further translation of this novel platform for AML treatment.

Stimulation of autologous proliferative and cytotoxic T-cell responses by “leukemic dendritic cells” derived from blast cells in acute myeloid leukemia

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2764-2771 ◽  
Author(s):  
Beth D. Harrison ◽  
Julie A. Adams ◽  
Mark Briggs ◽  
Michelle L. Brereton ◽  
John A. Liu Yin
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Dendritic Cells ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Responses ◽  
Cell Responses ◽  
Antigen Presenting ◽  
Acute Myeloid ◽  
Stimulation Of

Abstract Effective presentation of tumor antigens is fundamental to strategies aimed at enrolling the immune system in eradication of residual disease after conventional treatments. Myeloid malignancies provide a unique opportunity to derive dendritic cells (DCs), functioning antigen-presenting cells, from the malignant cells themselves. These may then co-express leukemic antigens together with appropriate secondary signals and be used to generate a specific, antileukemic immune response. In this study, blasts from 40 patients with acute myeloid leukemia (AML) were cultured with combinations of granulocyte-macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor α, and development to DCs was assessed. After culture, cells from 24 samples exhibited morphological and immunophenotypic features of DCs, including expression of major histocompatibility complex class II, CD1a, CD83, and CD86, and were potent stimulators in an allogeneic mixed lymphocyte reaction (MLR). Stimulation of autologous T-cell responses was assessed by the proliferative response of autologous T cells to the leukemic DCs and by demonstration of the induction of specific, autologous, antileukemic cytotoxicity. Of 17 samples, 11 were effective stimulators in the autologous MLR, and low, but consistent, autologous, antileukemic cytotoxicity was induced in 8 of 11 cases (mean, 27%; range, 17%-37%). This study indicates that cells with enhanced antigen-presenting ability can be generated from AML blasts, that these cells can effectively prime autologous cytotoxic T cells in vitro, and that they may be used as potential vaccines in the immunotherapy of AML.

scholarly journals 871 Construction and evaluation of interleukin 3 (IL3)-zetakine redirected cytolytic T Cells for the treatment of CD123 expressing acute myeloid leukemia

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A912-A912
Author(s):  
Rebecca Moeller ◽  
Julian Scherer ◽  
Sadik Kassim
Keyword(s):  
Stem Cells ◽  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Myeloid Leukemia ◽  
Cell Activation ◽  
Jurkat Cells ◽  
Leukemic Stem Cells ◽  
Cd69 Expression ◽  
Acute Myeloid

BackgroundAcute Myeloid Leukemia (AML) is an aggressive bone marrow malignancy, characterized by the presence of leukemic blasts in the peripheral blood of patients. Poor AML prognoses1 are largely attributable to high rates of disease relapse, of which CD123+ leukemic stem cells (LSCs) are the primary cause.2 3 CD123, the alpha-chain of the IL3 cytokine receptor,6 has been identified as a favorable therapeutic AML target, overexpressed in both LSCs and blasts.4 5 We sought to direct T cells to CD123+ AML cells via cell surface tethered IL3 (termed ”IL3-zetakine”).7 The use of a zetakine instead of a chimeric antigen receptor (CAR) construct enables structure-guided site-directed mutagenesis to increase binding affinity and alter target cell signaling without detrimental T cell hyperactivation.MethodsZetakine constructs were designed using IL3 sequences bound to a transmembrane domain and intracellular costimulatory and CD3z signaling domains. The constructs were transduced into Jurkat cells with lentiviral vectors (LVV). T cell activation via CD69 expression was assessed via flow cytometry of sorted IL3 zetakine-positive Jurkat cells after co-culture with MOLM13 AML cells. Lead constructs were selected based on initial transduction percentage and activation response. In vitro functionality of each IL3 zetakine was tested with LVV transduced primary T cells by flow cytometry.ResultsZetakine constructs yielded a wide range of transduction percentages in Jurkat cells (0 – 98%) prior to sorting. In co-cultures with CD123+ MOLM13 AML cells, Jurkat cells expressing wildtype IL3 constructs lacking a costimulatory domain induced the highest level of CD69 expression (18.7% CD69+ T cells) in an antigen-specific manner (5.3-fold increase of CD69+ T cells over those cultured with MOLM13 CD123KO cells). The K110E mutant IL3 was reported to exhibit a 40-fold increased affinity over wildtype,8 but it showed no detectable zetakine function. However, additional mutant IL3 zetakines increased Jurkat cell activation up to 5.8-fold. Antigen-specific increases in CD69, as well as CD25, surface expression were also observed with zetakine-transduced primary T cells co-cultured with MOLM13 cells, in addition to target cell killing comparable to antibody-based CD123CAR T-cells.ConclusionsThis work establishes IL3 zetakines as a viable alternative to traditional CD123-targeted CAR constructs. Structure-guided IL3 zetakine mutants with altered affinity and activation profiles will further our understanding of CD123-specific cytotoxicity modulation without inducing acute T cell hyperactivation and exhaustion. These results indicate the ability of IL3 zetakine-expressing T cells to kill CD123-expressing AML cells and illustrate the potential of this novel class of therapeutics.ReferencesGanzel C, et al. Very poor long-term survival in past and more recent studies for relapsed AML patients: the ECOG-ACRIN experience. American journal of hematology 2018:10.1002/ajh.25162.Shlush LI, et al. Tracing the origins of relapse in acute myeloid leukaemia to stem cells. Nature 2017;547(7661):104–108.Hanekamp D, Cloos J, Schuurhuis GJ. Leukemic stem cells: identification and clinical application. International Journal of Hematology 2017;105(5):549–557.Bras AE, et al. CD123 expression levels in 846 acute leukemia patients based on standardized immunophenotyping. Cytometry part B: Clinical Cytometry 2019;96(2):134–142.Sugita M, Guzman ML. CD123 as a therapeutic target against malignant stem cells. Hematology/Oncology clinics of North America 2020;34(3):553–564.Mingyue S, et al. CD123: a novel biomarker for diagnosis and treatment of leukemia. Cardiovascular & Hematological Disorders-Drug Targets 2019;19(3):195–204.Kahlon KS, et al. Specific recognition and killing of glioblastoma multiforme by interleukin 13-zetakine redirected cytolytic T cells. Cancer Res 2004;64(24):9160–6.Bagley CJ, et al. A discontinuous eight-amino acid epitope in human interleukin-3 binds the alpha-chain of its receptor. J Biol Chem 1996;271(50):31922–8.

scholarly journals Checkpoint Blockade in Combination with CD33 Chimeric Antigen Receptor T Cell Therapy and Hypomethylating Agent Against Acute Myeloid Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1383-1383 ◽  
Author(s):  
Tongyuan Xue ◽  
Marissa Del Real ◽  
Emanuela Marcucci ◽  
Candida Toribio ◽  
Sonia Maryam Setayesh ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Therapy ◽  
Programmed Death ◽  
Car T ◽  
Acute Myeloid

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. The cure rate for primary AML patients is only 35% and decreases with age. Novel and effective immunotherapies for patients with relapsed and/or refractory (r/r) AML remain an urgent unmet need. CD33 is an attractive immunotherapeutic target for myeloid malignancies given its expression on more than 85% of AML patient samples. We therefore set out to design and test CD33 chimeric antigen receptor (CD33CAR) T cells preclinically as a single agent and in combinational therapy. To assess antileukemic responses of CD33CAR T cells in vitro and in vivo, we enriched CD4/CD8 T cells from peripheral blood mononuclear cells (PBMCs) and genetically modified them to express a second-generation CD33CAR. CD33CAR T cells exhibited potent antigen dependent CD107a degranulation, IFN-γ production and killing activities against AML cells in vitro. Using a NOD-SCID-IL2Rgnull (NSG) xenograft model engrafted with MOLM-14-ffluc, a CD33 expressing AML cell line transduced with lentivirus carrying firefly luciferase (ffluc) and enhanced green fluorescent protein (eGFP), 3 million CD33CAR or mock T cells were introduced intravenously. CD33 CAR T cell-treated group displayed 98.2% leukemic regression 4 days post CAR T infusion, and 99.6% reduction on day 31. Bioluminescent imaging (BLI) and Kaplan-Meier analysis demonstrated that CD33CAR T cells significantly decreased leukemic burden and prolonged overall survival compared to mock T cells in vivo. Decitabine, a DNA hypomethylating agent (HMA), is a main therapeutic agent for treating AML. We observed HMA treatment led to increased CD33 expression on MOLM-14 cells in vitro. We hypothesized that decitabine can potentiate CD33CAR T cell-mediated AML killing by increasing CD33 expression. MOLM-14 cells were treated with either decitabine alone, CD33CAR T cells alone, or sequential treatment using various concentrations of decitabine or DMSO followed by CD33CAR or mock T cells in an E:T ratio of 1:100. We determined the target specific killing activities in each group using flow cytometric based analysis 48 and 96 hours later. The decitabine followed by CD33CAR T cells treatment reproducibly resulted in the most robust antileukemic activity with 80.6% MOLM-14 cells killed. In comparison, CD33CAR T cells or decitabine monotherapy resulted in 11.5% and 50.9% killing, respectively. In vivo testing of the combinational effects of decitabine and CD33CAR T cells are underway and will be updated at the meeting. Finally, checkpoint blockade targeting programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) has shown survival benefits, particularly in combination with HMA, for patients with r/r AML (Daver et al. 2019). We observed elevated PD-L1 expression on residual AML blasts that survived the treatment with decitabine in combination with CD33CAR T cells. Therefore, we hypothesized that blockade of PD-1/PD-L1 interaction might further improve the antileukemic effect of CD33CAR T cells against AML cells post antigen induction by decitabine. MOLM-14 cells were treated with decitabine for 2 days and CD33CAR T cells were added in an E:T ratio of 1:75. Anti-PD-1 or IgG4 antibody was added to the culture at various concentrations. The most robust CD33 specific killing was seen in the culture with anti-PD-1 antibody added. Further characterization are underway and will be presented. Taken together, our preclinical findings have demonstrated the potency of the CD33CAR T cell therapy and ways to optimize its efficacy. Our results support clinical translation of CD33CAR T cells for patients with AML. Disclosures Budde: F. Hoffmann-La Roche Ltd: Consultancy.

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