11 research outputs found
Immunotherapeutic targeting of tumor-associated macrophages
The development of CAR T cell technology allows for MHC-independent recognition of a native target antigen by T cells. In august 2017, the first CD19-specific CAR T cell therapy was approved in the U.S. for the treatment of B-lymphoid malignancies. However, the translation into solid tumors has proven more challenging. Main obstacles include a paucity of appropriate tumor-specific antigens, and difficulties in facilitating CAR T cell migration to the tumor site and survival in the hostile microenvironment of the tumor.
Based on previous work from our group showing that re-polarization of tumor-associated macrophages (TAMs) by CD4+ T cells can induce tumor regression, we hypothesized that CAR T cell targeting of TAM-specific antigens would lead to TAM re-polarization towards the tumoricidal phenotype with subsequent elimination of cancer cells. Given the abundance of
macrophages in most solid tumors, this identifies a novel approach to cancer immunotherapy.
In this study, we engineered a CAR construct specific for folate receptor beta (FRβ), a protein reported to be overexpressed that is overexpressed on TAMs, and investigated the use of FRβ-specific CAR T cells on TAMs in vitro and in vivo in established solid tumors. We found that CAR T binding activates and re-polarizes TAMs towards the pro-inflammatory and anti-tumor M1 phenotype, which are able to kill tumor cells in vitro. Re-educated TAMs secreted significantly higher amounts of pro-inflammatory cytokines and NO, and inhibition of iNOS activity completely abrogated macrophage-mediated killing, indicating that the anti-tumor effect triggered by FRβ-specific CAR T cells is dependent on iNOS activity in vitro. To fully assess the therapeutic potential of these CAR T cells, adoptive cell transfer experiments were performed in immunocompetent mouse tumor models. TAM-directed CAR T cell therapy slowed down tumor growth and led to regression of large, established tumors in models of melanoma and colon cancer and induced long-term remission in a subset of the treated animals.
Our findings highlight a novel approach to CAR T cell immunotherapy for solid tumors which is independent on the expression or secretion of tumor-specific antigens by the tumor cells, and which actively counteracts local immunosuppression at the tumor site.submittedVersionM-BIOTE
Tumor-derived GDF-15 blocks LFA-1 dependent T cell recruitment and suppresses responses to anti-PD-1 treatment
Immune checkpoint blockade therapy is beneficial and even curative for some cancer patients. However, the majority don't respond to immune therapy. Across different tumor types, pre-existing T cell infiltrates predict response to checkpoint-based immunotherapy. Based on in vitro pharmacological studies, mouse models and analyses of human melanoma patients, we show that the cytokine GDF-15 impairs LFA-1/β2-integrin-mediated adhesion of T cells to activated endothelial cells, which is a pre-requisite of T cell extravasation. In melanoma patients, GDF-15 serum levels strongly correlate with failure of PD-1-based immune checkpoint blockade therapy. Neutralization of GDF-15 improves both T cell trafficking and therapy efficiency in murine tumor models. Thus GDF-15, beside its known role in cancer-related anorexia and cachexia, emerges as a regulator of T cell extravasation into the tumor microenvironment, which provides an even stronger rationale for therapeutic anti-GDF-15 antibody development
Access to a Cu<sup>II</sup>–O–Cu<sup>II</sup> Motif: Spectroscopic Properties, Solution Structure, and Reactivity
We report a complex with a rare Cu<sup>II</sup>–O–Cu<sup>II</sup> structural motif that is
stable at room temperature, which
allows its in-depth characterization by a variety of spectroscopic
methods. Interest in such compounds is fueled by the recent discovery
that a Cu<sup>II</sup>–O–Cu<sup>II</sup> species on
the surface of Cu-ZSM-5 is capable of oxidizing methane to methanol,
and this in turn ties into mechanistic discussions on the methane
oxidation at the dicopper site within the particulate methane monooxygenase.
For the synthesis of our <b>Cu</b><sub><b>2</b></sub><b>O</b> complex we have developed a novel, neutral ligand system, <b>FurNeu</b>, exhibiting two <i>N</i>-(<i>N</i>′,<i>N</i>′-dimethylaminoethyl)Â(2-pyridylmethyl)Âamino
binding pockets connected by a dibenzofuran spacer. The reaction of <b>FurNeu</b> with CuCl yielded [<b>FurNeu</b>]Â(Cu<sub>2</sub>(μ-Cl))Â(CuCl<sub>2</sub>), <b>1</b>, demonstrating the
geometric potential of the ligand to stabilize Cu–X–Cu
moieties. A Cu<sup>I</sup> precursor with weakly coordinating anions
was chosen in the next step, namely [CuÂ(NCCH<sub>3</sub>)<sub>4</sub>]ÂOTf, which led to the formation of [<b>FurNeu</b>]Â(CuÂ(NCCH<sub>3</sub>))<sub>2</sub>(OTf)<sub>2</sub>, <b>3</b>. Treatment
of <b>3</b> with O<sub>2</sub> or PhIO led to identical green
solutions, whose UV–vis spectra were markedly different from
the one displayed by [<b>FurNeu</b>]Â(Cu)<sub>2</sub>(OTf)<sub>4</sub>, <b>4</b>, prepared independently from <b>FurNeu</b> and CuÂ(OTf)<sub>2</sub>. Further investigations including PhIO consumption
experiments, NMR and UV–vis spectroscopy, HR-ESI mass spectrometry,
and protonation studies led to the identification of the green product
as [<b>FurNeu</b>]Â(Cu<sub>2</sub>(μ-O))Â(OTf)<sub>2</sub>, <b>5</b>. DOSY NMR spectroscopy confirmed its monomeric character.
Over longer periods of time <b>5</b> decomposes to give [CuÂ(picoloyl)<sub>2</sub>], formed through an oxidative N-dealkylation reaction followed
by further oxidation of the ligand. Due to its slow decomposition
reaction, all attempts to crystallize <b>5</b> failed. However,
its structure in solution could be determined by EXAFS analysis in
combination with DFT calculations, which revealed a Cu–O–Cu
angle that amounts to 105.17°. Moreover, TDDFT calculations helped
to rationalize the UV–vis absorptions of <b>5</b>. The
reactivity of complex <b>5</b> with 2,4-di-<i>tert</i>-butylphenol, DTBP, was also investigated; the initially formed biphenol
product, TBBP, was found to further react in the presence of excessive
O<sub>2</sub> to yield 2,4,7,9-tetra-<i>tert</i>-butyloxepinoÂ[2,3-b]Âbenzofuran,
TBOBF, via an intermediate diphenoquinone. It turned out that <b>5</b>, or its precursor <b>3</b>, can even be employed as
a catalyst for the oxidation of DTBP to TBBP or for the oxidation
of TBBP to TBOBF
Neurodegeneration by α-synuclein-specific T cells in AAV-A53T-α-synuclein Parkinson’s disease mice
Background
Antigen-specific neuroinflammation and neurodegeneration are characteristic for neuroimmunological diseases. In Parkinson’s disease (PD) pathogenesis, α-synuclein is a known culprit. Evidence for α-synuclein-specific T cell responses was recently obtained in PD. Still, a causative link between these α-synuclein responses and dopaminergic neurodegeneration had been lacking. We thus addressed the functional relevance of α-synuclein-specific immune responses in PD in a mouse model.
Methods
We utilized a mouse model of PD in which an Adeno-associated Vector 1/2 serotype (AAV1/2) expressing human mutated A53T-α-Synuclein was stereotactically injected into the substantia nigra (SN) of either wildtype C57BL/6 or Recombination-activating gene 1 (RAG1) mice. Brain, spleen, and lymph node tissues from different time points following injection were then analyzed via FACS, cytokine bead assay, immunohistochemistry and RNA-sequencing to determine the role of T cells and inflammation in this model. Bone marrow transfer from either CD4/CD8, CD4/CD8, or CD4/CD8 (JHD) mice into the RAG-1 mice was also employed. In addition to the in vivo studies, a newly developed A53T-α-synuclein-expressing neuronal cell culture/immune cell assay was utilized.
Results
AAV-based overexpression of pathogenic human A53T-α-synuclein in dopaminergic neurons of the SN stimulated T cell infiltration. RNA-sequencing of immune cells from PD mouse brains confirmed a pro-inflammatory gene profile. T cell responses were directed against A53T-α-synuclein-peptides in the vicinity of position 53 (68–78) and surrounding the pathogenically relevant S129 (120–134). T cells were required for α-synuclein-induced neurodegeneration in vivo and in vitro, while B cell deficiency did not protect from dopaminergic neurodegeneration.
Conclusions
Using T cell and/or B cell deficient mice and a newly developed A53T-α-synuclein-expressing neuronal cell culture/immune cell assay, we confirmed in vivo and in vitro that pathogenic α-synuclein peptide-specific T cell responses can cause dopaminergic neurodegeneration and thereby contribute to PD-like pathology
Tumor-derived GDF-15 blocks LFA-1 dependent T cell recruitment and suppresses responses to anti-PD-1 treatment
Abstract Immune checkpoint blockade therapy is beneficial and even curative for some cancer patients. However, the majority don’t respond to immune therapy. Across different tumor types, pre-existing T cell infiltrates predict response to checkpoint-based immunotherapy. Based on in vitro pharmacological studies, mouse models and analyses of human melanoma patients, we show that the cytokine GDF-15 impairs LFA-1/β2-integrin-mediated adhesion of T cells to activated endothelial cells, which is a pre-requisite of T cell extravasation. In melanoma patients, GDF-15 serum levels strongly correlate with failure of PD-1-based immune checkpoint blockade therapy. Neutralization of GDF-15 improves both T cell trafficking and therapy efficiency in murine tumor models. Thus GDF-15, beside its known role in cancer-related anorexia and cachexia, emerges as a regulator of T cell extravasation into the tumor microenvironment, which provides an even stronger rationale for therapeutic anti-GDF-15 antibody development