Chemotherapy-induced immunogenic cell death can favor dendritic cell (DC) cross-priming of tumor-associated antigens for T cell activation thanks to the release of damage-associated molecular ...patterns, including ATP. Here, we tested the hypothesis that in acute myeloid leukemia (AML), ATP release, along with its well-known immune stimulatory effect, may also contribute to the generation of an immune suppressive microenvironment. In a cohort of AML patients, undergoing combined daunorubicin and cytarabine chemotherapy, a population of T regulatory cells (Tregs) with suppressive phenotype, expressing the immune checkpoint programmed cell death protein 1 (PD-1), was significantly increased. Moving from these results, initial
data showed that daunorubicin was more effective than cytarabine in modulating DC function toward Tregs induction and such difference was correlated with the higher capacity of daunorubicin to induce ATP release from treated AML cells. DCs cultured with daunorubicin-treated AML cells upregulated indoleamine 2,3-dioxygenase 1 (IDO1), which induced anti-leukemia Tregs. These data were confirmed
as daunorubicin-treated mice show an increase in extracellular ATP levels with increased number of Tregs, expressing PD-1 and IDO1
CD39
DCs. Notably, daunorubicin failed to induce Tregs and tolerogenic DCs in mice lacking the ATP receptor P2X7. Our data indicate that ATP release from chemotherapy-treated dying cells contributes to create an immune suppressive microenvironment in AML.
High-grade sarcomas are a heterogeneous group of aggressive tumors arising in bone and soft tissues. After relapse, treatment options are limited. The multi-targeted receptor tyrosine kinase ...inhibitors (TKIs) sunitinib and inhibitor of PD-1 (anti-PD-1) nivolumab have shown antitumor activity in selected subtypes. In this study, we examine the role of TKIs and PD-1 based therapy in
cocultures of sarcoma.
The human osteosarcoma (SaOS-2) and synovial sarcoma (SYO-1) cell lines were treated with sunitinib. After cell death and proliferation assessment, expression of PD-L1 was analyzed by flow cytometry. Sunitinib-treated sarcoma cells were cocultured with dendritic cells (DCs), and the phenotype of mature DCs was determined by flow cytometry. Mature DCs were cultured with autologous T cells. PD-1 expression on T cells, their proliferation, T regulatory cell (Tregs) induction and IFN-γ production, before and after nivolumab exposure, were analyzed.
Along with its anti-proliferative and direct pro-apoptotic effect on sarcoma cell lines, sunitinib prompted PD-L1 upregulation on sarcoma cells. Interestingly, sunitinib-treated sarcoma cells drive DCs to full maturation and increase their capacity to induce sarcoma-reactive T cells to produce IFN-γ. Conversely, no effect on T cell proliferation and T cell subpopulation composition was observed. Moreover, both bone and synovial sarcoma cell lines induced Tregs through DCs but sunitinib treatment completely abrogated Treg induction. Finally, sarcoma cell lines induced PD-1 upregulation on both effector T cells and Tregs when loaded into DCs, providing a rationale for using PD-1 blockade. Indeed, PD-1 blockade by nivolumab synergized with sunitinib in inducing IFN-γ-producing effector T cells.
Taken together, our
data indicate that the treatment of sarcoma cells with sunitinib can exert significant changes on immune cell subsets toward immune activation, leading to DC-based cross-priming of IFN-γ-producing effector T cells and reduced Treg induction. PD-1 blockade with nivolumab has a synergistic effect with sunitinib, supporting the use of TKI and anti-PD-1 approach in sarcomas, and perhaps in other cancers. DC-targeted drugs, including toll-like receptor 3 inhibitors and CD47 inhibitors, are under development and our preclinical model might help to better design their clinical application.
In solid tumors and hematological malignancies, including acute myeloid leukemia, some chemotherapeutic agents, such as anthracyclines, have proven to activate an immune response via dendritic ...cell-based cross-priming of anti-tumor T lymphocytes. This process, known as immunogenic cell death, is characterized by a variety of tumor cell modifications, i.e., cell surface translocation of calreticulin, extracellular release of adenosine triphosphate and pro-inflammatory factors, such as high mobility group box 1 proteins. However, in addition to with immunogenic cell death, chemotherapy is known to induce inflammatory modifications within the tumor microenvironment, which may also elicit immunosuppressive pathways. In particular, DCs may be driven to acquire tolerogenic features, such as the overexpression of indoleamine 2,3-dioxygensase 1, which may ultimately hamper anti-tumor T-cells via the induction of T regulatory cells. The aim of this review is to summarize the current knowledge about the mechanisms and effects by which chemotherapy results in both activation and suppression of anti-tumor immune response. Indeed, a better understanding of the whole process underlying chemotherapy-induced alterations of the immunological tumor microenvironment has important clinical implications to fully exploit the immunogenic potential of anti-leukemia agents and tune their application.
Natural killer (NK) cells are circulating CD3
lymphocytes, which express CD56 or CD16 and an array of inhibitory receptors, called killer-immunoglobulin-like receptors (KIRs). Alloreactive KIR-ligand ...mismatched NK cells crucially mediate the innate immune response and have a well-recognized antitumor activity. Adoptive immunotherapy with alloreactive NK cells determined promising clinical results in terms of response in acute myeloid leukemia (AML) patients and several data demonstrated that response can be influenced by the composition of NK graft. Several data show that there is a correlation between NK alloreactivity and clinical outcome: in a cohort of AML patients who received NK infusion with active disease, more alloreactive NK cell clones were found in the donor repertoire of responders than in non-responders. These findings demonstrate that the frequency of alloreactive NK cell clones influence clinical response in AML patients undergoing NK cell immunotherapy. In this work, we will review the most recent preclinical and clinical data about the impact of alloreactive NK cells features other than frequency of alloreactive clones and cytokine network status on their anti-leukemic activity. A better knowledge of these aspects is critical to maximize the effects of this therapy in AML patients.
In the last years, dendritic cells (DC) have been evaluated for antitumor vaccination. Although DC-based vaccines have raised great expectations, their clinical translation has been largely ...disappointing. For these results, several explanations have been proposed. In particular, the concomitant expression by DCs of tolerogenic pathways, such as the immunosuppressive agent indoleamine 2,3-dioxygenase-1 (IDO1), has been demonstrated. The aim of this study is to evaluate both the stimulatory and the tolerogenic feature of monocyte-derived DCs (Mo-DCs) after maturation with PGE2. In particular, the role of IDO1 expression in PGE2-matured Mo-DCs has been addressed. Here we show that PGE2, which is required for full maturation of DCs, is one mediator of DC tolerance by enhancing IDO1. PGE2-mediated expression of IDO1 results in the production of kynurenine, in the generation of Tregs, and in the inhibition of either the allogeneic or the autologous antigen-specific stimulatory capacity of DCs. When pulsed with leukemic lysates and matured with PGE2, DCs are impaired in the induction of IFN-γ secreting CD4+ and CD8+ T cells due to IDO1 upregulation. Moreover, the inhibition of IDO1 enhances the antileukemic response. Overall, these results point toward the use of IDO1 inhibitors to enhance the vaccination capacity of DCs, matured with PGE2.
Acute myeloid leukemia (AML) is a disease, which mainly affects the elderly population. Unfortunately, the prognosis of patients aged >65 years is dismal, with 1-year overall survival approaching 10% ...with conventional therapies. The hypothesis of harnessing the immune system against cancer, including leukemia, has been postulated for a long time, and several clinical attempts have been made in this field. In the last years, we increased our knowledge about the interplay between AML and immune cells, but no major improvement has been translated, up to now, from bench to bedside. However, the outstanding results coming from the modern immuno-oncology trials with new drugs have granted a new interest for immunotherapy in AML. Accordingly, the elderly population represents an ideal target, given the low percentage of patients eligible for allogeneic stem cell transplant. With that in mind, in the era of immunotherapy, we consider immunosenescence as the optimal background to start investigating a biology-driven approach to AML therapy in the elderly. By taking into account the physiological age-related changes of immune response, more personalized and tailored use of the new drugs and strategies harnessing the immune system against AML, has the potential to increase their efficacy and impact on clinical outcomes.
Group 2 innate lymphoid cells (ILC2s) are involved in human diseases, such as allergy, atopic dermatitis and nasal polyposis, but their function in human cancer remains unclear. Here we show that, in ...acute promyelocytic leukaemia (APL), ILC2s are increased and hyper-activated through the interaction of CRTH2 and NKp30 with elevated tumour-derived PGD2 and B7H6, respectively. ILC2s, in turn, activate monocytic myeloid-derived suppressor cells (M-MDSCs) via IL-13 secretion. Upon treating APL with all-trans retinoic acid and achieving complete remission, the levels of PGD2, NKp30, ILC2s, IL-13 and M-MDSCs are restored. Similarly, disruption of this tumour immunosuppressive axis by specifically blocking PGD2, IL-13 and NKp30 partially restores ILC2 and M-MDSC levels and results in increased survival. Thus, using APL as a model, we uncover a tolerogenic pathway that may represent a relevant immunosuppressive, therapeutic targetable, mechanism operating in various human tumour types, as supported by our observations in prostate cancer.Group 2 innate lymphoid cells (ILC2s) modulate inflammatory and allergic responses, but their function in cancer immunity is still unclear. Here the authors show that, in acute promyelocytic leukaemia, tumour-activated ILC2s secrete IL-13 to induce myeloid-derived suppressor cells and support tumour growth.
In acute myeloid leukemia (AML), alloreactive natural killer (NK) cells are crucial mediators of immune responses after haploidentical stem cell transplantation. Allogeneic NK cell infusions have ...been adoptively transferred with promising clinical results. We aimed at determining whether the composition of NK graft in terms of frequency of alloreactive NK cells influence the clinical response in a group of elderly AML patients undergoing NK immunotherapy.
Seventeen AML patients, in first complete remission (CR; median age 64 years, range 53-73) received NK cells from haploidentical KIR-ligand-mismatched donors after fludarabine/cyclophosphamide chemotherapy, followed by IL2. To correlate donor NK cell activity with clinical response, donor NK cells were assessed before and after infusion.
Toxicity was moderate, although 1 patient died due to bacterial pneumonia and was censored for clinical follow-up. With a median follow-up of 22.5 months (range, 6-68 months), 9 of 16 evaluable patients (0.56) are alive disease-free, whereas 7 of 16 (0.44) relapsed with a median time to relapse of 9 months (range, 3-51 months). All patients treated with molecular disease achieved molecular CR. A significantly higher number of donor alloreactive NK cell clones was observed in responders over nonresponders. The infusion of higher number of alloreactive NK cells was associated with prolonged disease-free survival (0.81 vs. 0.14, respectively;P= 0.03).
Infusion of purified NK cells is feasible in elderly AML patients as post-CR consolidation strategy. The clinical efficacy of adoptively transferred haploidentical NK cells may be improved by infusing high numbers of alloreactive NK cells.
Recent studies have disclosed the involvement of T cells in narcolepsy type 1 pathogenesis. We characterized the T cell subsets distribution in a recent-onset child at two different time points, two ...months from disease onset (T0) and 10 months later (follow-up), respectively.
Peripheral blood mononuclear cells (PBMCs) and cerebrospinal fluid (CSF) lymphocytes were characterized by flow cytometry at both evaluations. The distribution of T cell subsets was compared between the two time points, and the fold change was calculated as the CSF/PBMC frequencies ratio.
The patient showed a 2-fold increase in the frequency of CD4+ EMRA T cells, and an increase of more than one and a half in the frequency of CD4+ CM T cells in CSF at follow-up compared to T0. Moreover, the distribution of CD4+ EM T cells was slightly increased at T0 compared to follow-up. In PBMCs, the CD4+ and CD8+ T cell subsets showed a slight decrease in CM cells at the follow-up. Finally, the CSF/PBMC fold-change ratio showed a 3-fold increase of CD4+ and CD8+ CM T cells at the follow-up, a rise up to 1.5-fold of CD4+ EMRA subsets and a slight decrease in CD4+ EM T cells.
Our data suggest that variations in the frequency of EM vs. CM of CD4+ and CD8+ T cell subsets in the CSF and in the CSF/PBMC fold change may represent a biological marker of disease progression.
•Narcolepsy Type 1 is a putative autoimmune-mediated disorder.•We characterized the peripheral and central T cell subsets in a recent onset patient initially and at follow up.•The variations in memory subsets of CD4+ and CD8+ T cells may mark the disease progression.•Further studies in larger childhood cohort may confirm the disease-specific T cells memory phenotype.
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