RESUMO
The low 5-year survival rate for patients with acute myeloid leukemia (AML), primarily caused due to disease relapse, emphasizes the need for better therapeutic strategies. Disease relapse is facilitated by leukemic stem cells (LSCs) that are resistant to standard chemotherapy and promote tumor growth. To target AML blasts and LSCs using natural killer (NK) cells, we have developed a trispecific killer engager (TriKETM) molecule containing a humanized anti-CD16 heavy chain camelid single-domain antibody (sdAb) that activates NK cells, an IL-15 molecule that drives NK-cell priming, expansion and survival, and a single-chain variable fragment (scFv) against human CLEC12A (CLEC12A TriKE). CLEC12A is a myeloid lineage antigen that is highly expressed by AML cells and LSCs, but not expressed by normal hematopoietic stem cells (HSCs), thus minimizing off-target toxicity. The CLEC12A TriKE induced robust NK-cell specific proliferation, enhanced NK-cell activation, and killing of both AML cell lines and primary patient-derived AML blasts in vitro while sparing healthy HSCs. Additionally, the CLEC12A TriKE was able to reduce tumor burden in preclinical mouse models. These findings highlight the clinical potential of the CLEC12A TriKE for the effective treatment of AML.
Assuntos
Imunoterapia/métodos , Interleucina-15/metabolismo , Células Matadoras Naturais/imunologia , Lectinas Tipo C/imunologia , Leucemia Mieloide Aguda/terapia , Receptores de IgG/imunologia , Receptores Mitogênicos/imunologia , Anticorpos de Domínio Único/farmacologia , Animais , Apoptose , Proliferação de Células , Feminino , Proteínas Ligadas por GPI/imunologia , Humanos , Lectinas Tipo C/antagonistas & inibidores , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Prognóstico , Receptores Mitogênicos/antagonistas & inibidores , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Altered BM hematopoiesis and immune suppression are hallmarks of myelodysplastic syndrome (MDS). While the BM microenvironment influences malignant hematopoiesis, the mechanism leading to MDS-associated immune suppression is unknown. We tested whether mesenchymal stromal cells (MSCs) contribute to this process. Here, we developed a model to study cultured MSCs from patients with MDS (MDS-MSCs) compared with those from aged-matched normal controls for regulation of immune function. MDS-MSCs and healthy donor MSCs (HD-MSCs) exhibited a similar in vitro phenotype, and neither had a direct effect on NK cell function. However, when MDS- and HD-MSCs were cultured with monocytes, only the MDS-MSCs acquired phenotypic and metabolic properties of myeloid-derived suppressor cells (MDSCs), with resulting suppression of NK cell function, along with T cell proliferation. A MSC transcriptome was observed in MDS-MSCs compared with HD-MSCs, including increased expression of the ROS regulator, ENC1. High ENC1 expression in MDS-MSCs induced suppressive monocytes with increased INHBA, a gene that encodes for a member of the TGF-ß superfamily of proteins. These monocytes also had reduced expression of the TGF-ß transcriptional repressor MAB21L2, further adding to their immune-suppressive function. Silencing ENC1 or inhibiting ROS production in MDS-MSCs abrogated the suppressive function of MDS-MSC-conditioned monocytes. In addition, silencing MAB21L2 in healthy MSC-conditioned monocytes mimicked the MDS-MSC-suppressive transformation of monocytes. Our data demonstrate that MDS-MSCs are responsible for inducing an immune-suppressive microenvironment in MDS through an indirect mechanism involving monocytes.
Assuntos
Células da Medula Óssea/patologia , Células Matadoras Naturais/imunologia , Células-Tronco Mesenquimais/metabolismo , Monócitos/imunologia , Síndromes Mielodisplásicas/patologia , Idoso , Idoso de 80 Anos ou mais , Células da Medula Óssea/imunologia , Estudos de Casos e Controles , Técnicas de Cocultura , Proteínas do Olho/genética , Perfilação da Expressão Gênica , Inativação Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas dos Microfilamentos/genética , Pessoa de Meia-Idade , Modelos Biológicos , Síndromes Mielodisplásicas/imunologia , Síndromes Mielodisplásicas/metabolismo , Neuropeptídeos/genética , Proteínas Nucleares/genética , Espécies Reativas de Oxigênio/metabolismo , Fator de Crescimento Transformador beta/metabolismoRESUMO
A major limitation of the use of cellular therapies is the loss of donor-derived cells because of immune incompatibility. While induced pluripotent stem (iPS) cells offer the potential for autologous transplant therapies, questions have been raised using a mouse model that specific antigens mediate the rejection of grafts after syngeneic transplants with iPS, but not embryonic stem (ES) cells. In this study, we examined whether the human homologs of these markers, HORMAD1, ZG16, and Cyp3A, are differentially expressed in human iPS versus ES cells, as well as undifferentiated and in vitro-differentiated cells. Both qRT-PCR and flow cytometric analyses demonstrated similar gene and protein expression profiles for iPS and ES cells regardless of differentiation state. Our data are consistent with a recent study in mice that showed no evidence of rejection of differentiated syngeneic iPS cells. Furthermore, our results suggest that expression of these gene products cannot predict differences in clinical outcomes between human iPS and ES-derived cells.