Chimeric antigen receptor (CAR) T cells have shown great promise in the treatment of hematologic malignancies but more variable results in the treatment of solid tumors and the persistence and ...expansion of CAR T cells within patients has been identified as a key correlate of antitumor efficacy. Lack of immunological “space”, functional exhaustion, and deletion have all been proposed as mechanisms that hamper CAR T-cell persistence. Here we describe the events following activation of third-generation CAR T cells specific for GD2. CAR T cells had highly potent immediate effector functions without evidence of functional exhaustion in vitro, although reduced cytokine production reversible by PD-1 blockade was observed after longer-term culture. Significant activation-induced cell death (AICD) of CAR T cells was observed after repeated antigen stimulation, and PD-1 blockade enhanced both CAR T-cell survival and promoted killing of PD-L1+ tumor cell lines. Finally, we assessed CAR T-cell persistence in patients enrolled in the CARPETS phase 1 clinical trial of GD2-specific CAR T cells in the treatment of metastatic melanoma. Together, these data suggest that deletion also occurs in vivo and that PD-1-targeted combination therapy approaches may be useful to augment CAR T-cell efficacy and persistence in patients.
Abstract Cord blood (CB) natural killer (NK) cells are promising effector cells for tumor immunotherapy but are currently limited by immune-suppressive cytokines in the tumor microenvironment, such ...as transforming growth factor (TGF-β). We observed that TGF-β inhibits expression of activating receptors such as NKG2D and DNAM1 and decreases killing activity against glioblastoma tumor cells through inhibition of perforin secretion. To overcome the detrimental effects of TGF-β, we engrafted a dominant negative TGF-β receptor II (DNRII) on CB-derived NK cells by retroviral transduction and evaluated their ability to kill glioblastoma cells in the presence of TGF-β. After manufacture using Good Manufacturing Practice–compliant methodologies and transduction with DNRII, CB-derived DNRII-transduced NK cells expanded to clinically relevant numbers and retained both their killing ability and their secretion of interferon-γ upon activation. More important, these cells maintained both perforin expression and NKG2D/DNMA1 expression in the presence of TGF-β allowing for recognition and killing of glioblastoma tumor cells. Hence, NK cells expressing a DNRII should have a functional advantage over unmodified NK cells in the presence of TGF-β-secreting tumors and may be an important therapeutic approach for patients with cancer.
A subset of regulatory B cells (Bregs) in mice negatively regulate T-cell immune responses through the secretion of regulatory cytokines such as IL-10 and direct cell-cell contact and have been ...linked to experimental models of autoimmunity, inflammation, and cancer. However, the regulatory function of Bregs in human disease is much less clear. Here we demonstrate that B cells with immunoregulatory properties are enriched within both the CD19+IgM+CD27+ memory and CD19+CD24hiCD38hi transitional B-cell subsets in healthy human donors. Both subsets suppressed the proliferation and interferon-γ production of CD3/CD28-stimulated autologous CD4+ T cells in a dose-dependent manner, and both relied on IL-10 secretion as well as cell-cell contact, likely mediated through CD80 and CD86, to support their full suppressive function. Moreover, after allogeneic stem cell transplantation, Bregs from patients with chronic graft-versus-host disease (cGVHD) were less frequent and less likely to produce IL-10 than were Bregs from healthy donors and patients without cGVHD. These findings suggest that Bregs may be involved in the pathogenesis of cGVHD and support future investigation of regulatory B cell–based therapy in the treatment of this disease.
•Human IgM memory B cells possess immunoregulatory properties analogous to transitional B cells.•IL-10–producing B cells are deficient in cGVHD.
Medulloblastoma (MB), the most common pediatric brain cancer, presents with a poor prognosis in a subset of patients with high risk disease, or at recurrence, where current therapies are ineffective. ...Cord blood (CB) natural killer (NK) cells may be promising off-the-shelf effector cells for immunotherapy due to their recognition of malignant cells without the need for a known target, ready availability from multiple banks, and their potential to expand exponentially. However, they are currently limited by immune suppressive cytokines secreted in the MB tumor microenvironment including Transforming Growth Factor β (TGF-β). Here, we address this challenge in in vitro models of MB.
CB-derived NK cells were modified to express a dominant negative TGF-β receptor II (DNRII) using retroviral transduction. The ability of transduced CB cells to maintain function in the presence of medulloblastoma-conditioned media was then assessed.
We observed that the cytotoxic ability of nontransduced CB-NK cells was reduced in the presence of TGF-β-rich, medulloblastoma-conditioned media (21.21 ± 1.19% killing at E:T 5:1 in the absence vs. 14.98 ± 2.11% in the presence of medulloblastoma-conditioned media, n = 8, p = 0.02), but was unaffected in CB-derived DNRII-transduced NK cells (21.11 ± 1.84% killing at E:T 5:1 in the absence vs. 21.81 ± 3.37 in the presence of medulloblastoma-conditioned media, n = 8, p = 0.85. We also observed decreased expression of CCR2 in untransduced NK cells (mean CCR2 MFI 826 ± 117 in untransduced NK + MB supernatant from mean CCR2 MFI 1639.29 ± 215 in no MB supernatant, n = 7, p = 0.0156), but not in the transduced cells. Finally, we observed that CB-derived DNRII-transduced NK cells may protect surrounding immune cells by providing a cytokine sink for TGF-β (decreased TGF-β levels of 610 ± 265 pg/mL in CB-derived DNRII-transduced NK cells vs. 1817 ± 342 pg/mL in untransduced cells; p = 0.008).
CB NK cells expressing a TGF-β DNRII may have a functional advantage over unmodified NK cells in the presence of TGF-β-rich MB, warranting further investigation on its potential applications for patients with medulloblastoma.
Natural killer (NK) cells are important mediators of anti-tumor immunity and are active against several hematologic malignancies, including multiple myeloma (MM). Umbilical cord blood (CB) is a ...promising source of allogeneic NK cells but large scale ex vivo expansion is required for generation of clinically relevant CB-derived NK (CB-NK) cell doses. Here we describe a novel strategy for expanding NK cells from cryopreserved CB units using artificial antigen presenting feeder cells (aAPC) in a gas permeable culture system. After 14 days, mean fold expansion of CB-NK cells was 1848-fold from fresh and 2389-fold from cryopreserved CB with >95% purity for NK cells (CD56(+)/CD3(-)) and less than 1% CD3(+) cells. Though surface expression of some cytotoxicity receptors was decreased, aAPC-expanded CB-NK cells exhibited a phenotype similar to CB-NK cells expanded with IL-2 alone with respect to various inhibitory receptors, NKG2C and CD94 and maintained strong expression of transcription factors Eomesodermin and T-bet. Furthermore, CB-NK cells formed functional immune synapses with and demonstrated cytotoxicity against various MM targets. Finally, aAPC-expanded CB-NK cells showed significant in vivo activity against MM in a xenogenic mouse model. Our findings introduce a clinically applicable strategy for the generation of highly functional CB-NK cells which can be used to eradicate MM.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
T cell factor 1 (TCF1) is required for memory and stem-like CD8
T cell functions. How TCF1 partners with other transcription factors to regulate transcription remains unclear. Here we show that ...negative elongation factor (NELF), an RNA polymerase II (Pol II) pausing factor, cooperates with TCF1 in T cell responses to cancer. Deletion of mouse Nelfb, which encodes the NELFB subunit, in mature T lymphocytes impairs immune responses to both primary tumor challenge and tumor antigen-mediated vaccination. Nelfb deletion causes more exhausted and reduced memory T cell populations, whereas its ectopic expression boosts antitumor immunity and efficacy of chimeric antigen receptor T-cell immunotherapy. Mechanistically, NELF is associated with TCF1 and recruited preferentially to the enhancers and promoters of TCF1 target genes. Nelfb ablation reduces Pol II pausing and chromatin accessibility at these TCF1-associated loci. Our findings thus suggest an important and rate-limiting function of NELF in anti-tumor immunity.
Despite the promise of immunotherapy such as the immune checkpoint inhibitors (ICIs) anti-PD-1 and anti-CTLA-4 for advanced melanoma, only 26%–52% of patients respond, and many experience grade ...III/IV immune-related adverse events. Motivated by the need for an effective therapy for patients non-responsive to clinically approved ICIs, we have developed a novel nanoimmunotherapy that combines locally administered Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) with systemically administered agonistic anti-CD137 monoclonal antibody therapy (aCD137). PBNP-PTT was administered at various thermal doses to melanoma cells
in vitro
, and was combined with aCD137
in vivo
to test treatment effects on melanoma tumor progression, animal survival, immunological protection against tumor rechallenge, and hepatotoxicity. When administered at a melanoma-specific thermal dose, PBNP-PTT elicits immunogenic cell death (ICD) in melanoma cells and upregulates markers associated with antigen presentation and immune cell co-stimulation
in vitro.
Consequently, PBNP-PTT eliminates primary melanoma tumors
in vivo
, yielding long-term tumor-free survival. However, the antitumor immune effects generated by PBNP-PTT cannot eliminate secondary tumors, despite significantly slowing their growth. The addition of aCD137 enables significant abscopal efficacy and improvement of survival, functioning through activated dendritic cells and tumor-infiltrating CD8
+
T cells, and generates CD4
+
and CD8
+
T cell memory that manifests in the rejection of tumor rechallenge, with no long-term hepatotoxicity. This study describes for the first time a novel and effective nanoimmunotherapy combination of PBNP-PTT with aCD137 mAb therapy for melanoma.
Cancer immunotherapy has long been used in the treatment of metastatic melanoma, and an anti-CTLA-4 monoclonal antibody treatment has recently been approved by the US Food and Drug Administration. ...Targeted therapies such as small molecule kinase inhibitors targeting deregulated mitogen-activated protein kinase (MAPK) signaling have markedly improved melanoma control in up to 50% of metastatic disease patients and have likewise been recently approved. Combination therapies for melanoma have been proposed as a way to exploit the high-level but short-term responses associated with kinase inhibitor therapies and the low-level but longer-term responses associated with immunotherapy. Cancer immunotherapy now includes adoptive transfer of autologous tumor-specific chimeric antigen receptor (CAR) T cells and this mode of therapy is a candidate for combination with small molecule drugs. This paper describes CART cells that target GD2-expressing melanoma cells and investigates the effects of approved MAPK pathway-targeted therapies for melanoma vemurafenib (Vem), dabrafenib (Dab), and trametinib (Tram) on the viability, activation, proliferation, and cytotoxic T lymphocyte activity of these CAR T cells, as well as on normal peripheral blood mononuclear cells. We report that, although all these drugs lead to inhibition of stimulated T cells at high concentrations in vitro, only Vem inhibited T cells at concentrations equivalent to reported plasma concentrations in treated patients. Although the combination of Dab and Tram also resulted in inhibition of T-cell effector functions at some therapeutic concentrations, Dab itself had little adverse effect on CAR T-cell function. These findings may have implications for novel therapeutic combinations of adoptive CAR T-cell immunotherapy and MAPK pathway inhibitors.
Purpose: Genetic engineering of human T lymphocytes to express tumor-directed chimeric antigen receptors (CAR) can produce antitumor
effector cells that bypass tumor immune escape mechanisms that are ...due to abnormalities in protein-antigen processing and
presentation. Moreover, these transgenic receptors can be directed to tumor-associated antigens that are not protein-derived,
such as the ganglioside GD2, which is expressed in a high proportion of melanoma cells.
Experimental Design: We generated chimeric T cells specific for the ganglioside GD2 by joining an extracellular antigen-binding domain derived
from the GD2-specific antibody sc14.G2a to cytoplasmic signaling domains derived from the T-cell receptor ζ-chain, with the
endodomains of the costimulatory molecules CD28 and OX40. We expressed this CAR in human T cells and assessed the targeting
of GD2-positive melanoma tumors in vitro and in a murine xenograft.
Results: Upon coincubation with GD2-expressing melanoma cells, CAR-GD2 T lymphocytes incorporating the CD28 and OX40 endodomains secreted
significant levels of cytokines in a pattern comparable with the cytokine response obtained by engagement of the native CD3
receptor. These CAR-T cells had antimelanoma activity in vitro and in our xenograft model, increasing the survival of tumor-bearing animals.
Conclusion: Redirecting human T lymphocytes to the tumor-associated ganglioside GD2 generates effector cells with antimelanoma activity
that should be testable in subjects with disease. (Clin Cancer Res 2009;15(18):5852â60)
The synovial sarcoma X breakpoint 2 (SSX2) belongs to a multigene family of cancer-testis antigens and can be found overexpressed in multiple malignancies. Its restricted expression in ...immune-privileged normal tissues suggest that SSX2 may be a relevant target antigen for chimeric antigen receptor (CAR) therapy. We have developed a T cell receptor (TCR)-like antibody (Fab/3) that binds SSX2 peptide 41-49 (KASEKIFYV) in the context of HLA-A∗-0201. The sequence of Fab/3 was utilized to engineer a CAR with the CD3 zeta intra-cellular domain along with either a CD28 or 4-1BB costimulatory endodomain. Human T cells from HLA-A2+ donors were transduced to mediate anti-tumor activity against acute myeloid leukemia (AML) tumor cells. Upon challenge with HLA-A2+/SSX2+ AML tumor cells, CAR-expressing T cells released interferon-γ and eliminated the tumor cells in a long-term co-culture assay. Using the HLA-A2+ T2 cell line, we demonstrated a strong specificity of the single-chain variable fragment (scFv) for SSX2 p41-49 and the closely related SSX3 p41-49, with no response against the others SSX-homologous peptides or unrelated homologous peptides. Since SSX3 has not been observed in tumor cells and expression cannot be induced by pharmacological intervention, SSX241-49 represents an attractive target for CAR-based cellular therapy to treat multiple types of cancer.
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The TCR-like antibody engineered as a chimeric antigen receptor (CAR) is able to target the cancer-testis antigen (CTA) SSX2 peptide 41-49 in an HLA-A∗0201 context. Because of the SSX2 expression pattern in cancers, a cell-therapy approach using T cells expressing the SSX241-49 CAR can be readily deployed to treat patients.
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