CD47 is an antiphagocytic ligand broadly expressed on normal and malignant tissues that delivers an inhibitory signal through the receptor signal regulatory protein alpha (SIRPα). Inhibitors of the ...CD47–SIRPα interaction improve antitumor antibody responses by enhancing antibody-dependent cellular phagocytosis (ADCP) in xenograft models. Endogenous expression of CD47 on a variety of cell types, including erythrocytes, creates a formidable antigen sink that may limit the efficacy of CD47-targeting therapies. We generated a nanobody, A4, that blocks the CD47–SIRPα interaction. A4 synergizes with anti–PD-L1, but not anti-CTLA4, therapy in the syngeneic B16F10 melanoma model. Neither increased dosing nor half-life extension by fusion of A4 to IgG2a Fc (A4Fc) overcame the issue of an antigen sink or, in the case of A4Fc, systemic toxicity. Generation of a B16F10 cell line that secretes the A4 nanobody showed that an enhanced response to several immune therapies requires near-complete blockade of CD47 in the tumor microenvironment. Thus, strategies to localize CD47 blockade to tumors may be particularly valuable for immune therapy.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer that is most frequently detected at advanced stages, limiting treatment options to systemic chemotherapy with modest clinical ...responses. Here, we review recent advances in targeted therapy and immunotherapy for treating subtypes of PDAC with diverse molecular alterations. We focus on the current preclinical and clinical evidence supporting the potential of these approaches and the promise of combinatorial regimens to improve the lives of patients with PDAC.
IL-3 finds its home in the brain Bertocchi, Alice; Dougan, Stephanie K.
Immunity (Cambridge, Mass.),
07/2023, Letnik:
56, Številka:
7
Journal Article
Recenzirano
Interleukin-3 (IL-3) induces emergency hematopoiesis in settings of acute inflammation. In this issue of Immunity, Kiss et al. find that IL-3 derived from astrocytes and CD4+ T cells is a key ...regulatory cytokine of the central nervous system, and increased IL-3 signaling exacerbates neuroinflammation.
Interleukin-3 (IL-3) induces emergency hematopoiesis in settings of acute inflammation. In this issue of Immunity, Kiss et al. find that IL-3 derived from astrocytes and CD4+ T cells is a key regulatory cytokine of the central nervous system, and increased IL-3 signaling exacerbates neuroinflammation.
LAG-3 is the third immune checkpoint pathway successfully targeted for cancer therapy. Although ineffective as a monotherapy, combination of LAG-3 and PD-1 blockade improves survival from advanced ...melanoma. In this issue of Cell, two studies in mice and a human clinical trial provide insights on LAG-3 in immune regulation.
LAG-3 is the third immune checkpoint pathway successfully targeted for cancer therapy. Although ineffective as a monotherapy, combination of LAG-3 and PD-1 blockade improves survival from advanced melanoma. In this issue of Cell, two studies in mice and a human clinical trial provide insights on LAG-3 in immune regulation.
Programmed death ligand 1 (PD-L1) is expressed on a number of immune and cancer cells, where it can downregulate antitumor immune responses. Its expression has been linked to metabolic changes in ...these cells. Here we develop a radiolabeled camelid single-domain antibody (anti-PD-L1 VHH) to track PD-L1 expression by immuno-positron emission tomography (PET). PET-CT imaging shows a robust and specific PD-L1 signal in brown adipose tissue (BAT). We confirm expression of PD-L1 on brown adipocytes and demonstrate that signal intensity does not change in response to cold exposure or β-adrenergic activation. This is the first robust method of visualizing murine brown fat independent of its activation state.Current approaches to visualise brown adipose tissue (BAT) rely primarily on markers that reflect its metabolic activity. Here, the authors show that PD-L1 is expressed on brown adipocytes, does not change upon BAT activation, and that BAT volume in mice can be measured by PET-CT with a radiolabeled anti-PD-L1 antibody.
Methods to introduce targeted double-strand breaks (DSBs) into DNA enable precise genome editing by increasing the rate at which externally supplied DNA fragments are incorporated into the genome ...through homologous recombination. The efficiency of these methods is limited by nonhomologous end joining (NHEJ), an alternative DNA repair pathway that competes with homology-directed repair (HDR). To promote HDR at the expense of NHEJ, we targeted DNA ligase IV, a key enzyme in the NHEJ pathway, using the inhibitor Scr7. Scr7 treatment increased the efficiency of HDR-mediated genome editing, using Cas9 in mammalian cell lines and in mice for all four genes examined, up to 19-fold. This approach should be applicable to other customizable endonucleases, such as zinc finger nucleases and transcription activator-like effector nucleases, and to nonmammalian cells with sufficiently conserved mechanisms of NHEJ and HDR.
Resolving how the early signaling events initiated by cell–cell interactions are transduced into diverse functional outcomes necessitates correlated measurements at various stages. Typical approaches ...that rely on bulk cocultures and population-wide correlations, however, only reveal these relationships broadly at the population level, not within each individual cell. Here, we present a microfluidics-based cell–cell interaction assay that enables longitudinal investigation of lymphocyte interactions at the single-cell level through microfluidic cell pairing, on-chip culture, and multiparameter assays, and allows recovery of desired cell pairs by micromanipulation for off-chip culture and analyses. Well-defined initiation of interactions enables probing cellular responses from the very onset, permitting single-cell correlation analyses between early signaling dynamics and later-stage functional outcomes within same cells. We demonstrate the utility of this microfluidic assay with natural killer cells interacting with tumor cells, and our findings suggest a possible role for the strength of early calcium signaling in selective coordination of subsequent cytotoxicity and IFN-gamma production. Collectively, our experiments demonstrate that this new approach is well-suited for resolving the relationships between complex immune responses within each individual cell.
We developed modified RBCs to serve as carriers for systemic delivery of a wide array of payloads. These RBCs contain modified proteins on their plasma membrane, which can be labeled in a ...sortase-catalyzed reaction under native conditions without inflicting damage to the target membrane or cell. Sortase accommodates a wide range of natural and synthetic payloads that allow modification of RBCs with substituents that cannot be encoded genetically. As proof of principle, we demonstrate site-specific conjugation of biotin to in vitro-differentiated mouse erythroblasts as well as to mature mouse RBCs. Thus modified, RBCs remain in the bloodstream for up to 28 d. A single domain antibody attached enzymatically to RBCs enables them to bind specifically to target cells that express the antibody target. We extend these experiments to human RBCs and demonstrate efficient sortase-mediated labeling of in vitro-differentiated human reticulocytes.
In this issue of Cancer Cell, Kumagai et al. reveal lactic acid as a mediator of checkpoint blockade resistance. Tumor-derived lactic acid promotes T regulatory cell (Treg) activity and impairs CD8+ ...T cell function. PD-1 blockade synergizes with lactic acid to enhance Treg suppression and impede antitumor immunity.
In this issue of Cancer Cell, Kumagai et al. reveal lactic acid as a mediator of checkpoint blockade resistance. Tumor-derived lactic acid promotes T regulatory cell (Treg) activity and impairs CD8+ T cell function. PD-1 blockade synergizes with lactic acid to enhance Treg suppression and impede antitumor immunity.
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