Targeting Notch in oncology: the path forward Majumder, Samarpan; Crabtree, Judy S; Golde, Todd E ...
Nature reviews. Drug discovery,
02/2021, Letnik:
20, Številka:
2
Journal Article
Recenzirano
Notch signalling is involved in many aspects of cancer biology, including angiogenesis, tumour immunity and the maintenance of cancer stem-like cells. In addition, Notch can function as an oncogene ...and a tumour suppressor in different cancers and in different cell populations within the same tumour. Despite promising preclinical results and early-phase clinical trials, the goal of developing safe, effective, tumour-selective Notch-targeting agents for clinical use remains elusive. However, our continually improving understanding of Notch signalling in specific cancers, individual cancer cases and different cell populations, as well as crosstalk between pathways, is aiding the discovery and development of novel investigational Notch-targeted therapeutics.
Canonical Notch signaling is initiated by γ-secretase-mediated cleavage of the Notch receptor, leading to the release of the active intra-cellular domain of Notch that migrates to the nucleus and ...interacts with RBP-Jκ, resulting in the activation of downstream target genes. While canonical Notch signaling is well known to play an active role in several steps during development as well in multiple cell fate decisions, recent evidence from both invertebrate and vertebrate systems indicates that non-canonical, RBP-Jκ-independent signaling is important in several cellular processes including oncogenesis and activation of T lymphocytes. These observations raise the possibility that, through an understanding of non-canonical Notch signaling, novel strategies for inhibiting Notch signaling may prove useful in the design of therapies targeted to block aberrant Notch activity. In this mini-review, we will examine the current data demonstrating a non-canonical role for Notch signaling in both cancer and the immune system and suggest a better understanding of non-canonical signaling may reveal novel strategies to block Notch signaling in disease.
We report here on protein–antibody conjugates (PACs) that are used for antibody‐directed delivery of protein therapeutics to specific cells. PACs have the potential to judiciously combine the merits ...of two prolific therapeutic approaches—biologics and antibody–drug conjugates. We utilize spherical polymer brushes to construct PACs using the combination of two simple and efficient functionally orthogonal click chemistries. In addition to the synthesis and characterization of these nanoparticles, we demonstrate that PACs are indeed capable of specifically targeting cells based on the presence of target antigen on the cell surface to deliver proteins. The potentially broad adaptability of PACs opens up new opportunities for targeted biologics in therapeutics and sensing.
Protein–antibody conjugates (PACs) have the potential to judiciously combine the merits of two prolific therapeutic approaches—biologics and antibody–drug conjugates—for antibody‐directed delivery of protein therapeutics to specific cells.
γ‐Secretase inhibitors (GSIs) are being actively repurposed as cancer therapeutics based on the premise that inhibition of NOTCH1 signaling in select cancers is therapeutic. Using novel assays to ...probe effects of GSIs against a broader panel of substrates, we demonstrate that clinical GSIs are pharmacologically distinct. GSIs show differential profiles of inhibition of the various NOTCH substrates, with some enhancing cleavage of other NOTCH substrates at concentrations where NOTCH1 cleavage is inhibited. Several GSIs are also potent inhibitors of select signal peptide peptidase (SPP/SPPL) family members. Extending these findings to mammosphere inhibition assays in triple‐negative breast cancer lines, we establish that these GSIs have different functional effects. We also demonstrate that the processive γ‐secretase cleavage pattern established for amyloid precursor protein (APP) occurs in multiple substrates and that potentiation of γ‐secretase cleavage is attributable to a direct action of low concentrations of GSIs on γ‐secretase. Such data definitively demonstrate that the clinical GSIs are not biological equivalents, and provide an important framework to evaluate results from ongoing and completed human trials with these compounds.
Synopsis
γ‐Secretase inhibitors (GSIs) have been repurposed to treat various human cancers. Using newly developed γ‐secretase cleavage assays and a breast cancer cell mammosphere inhibition assay, this study demonstrates that four clinical GSIs are neither pharmacologically nor functionally equivalent.
In vitro and cell‐based assays for human NOTCH1–4 proteins enable facile study of γ‐secretase cleavage and the effects of GSIs, as well as establish sites of cleavage.
Dose–response studies with clinical GSIs reveal markedly different pharmacologic properties.
Studies in triple‐negative breast cancer cell lines show that the clinical GSIs are functionally distinct.
Uncertainty remains regarding the properties of a GSI that are associated with potency in the mammosphere inhibition assay, and might be predictive of a therapeutic effect in human cancer.
γ‐Secretase inhibitors (GSIs) have been repurposed to treat various human cancers. Using newly developed γ‐secretase cleavage assays and a breast cancer cell mammosphere inhibition assay, this study demonstrates that four clinical GSIs are neither pharmacologically nor functionally equivalent.
Notch drives critical decisions in a multitude of developmental decisions in many invertebrate and vertebrate organisms including flies, worms, fish, mice and humans. Therefore, it is not surprising ...that Notch family members also play a key role in cell fate choices in the vertebrate immune system. This review highlights the critical function of Notch in the development of mature T lymphocytes from hematopoietic precursors and describes the role of Notch in mature T cell activation, proliferation and differentiation.
Myeloid-derived suppressor cells (MDSC) are a major obstacle to promising forms of cancer immunotherapy, but tools to broadly limit their immunoregulatory effects remain lacking. In this study, we ...assessed the therapeutic effect of the humanized anti-Jagged1/2-blocking antibody CTX014 on MDSC-mediated T-cell suppression in tumor-bearing mice. CTX014 decreased tumor growth, affected the accumulation and tolerogenic activity of MDSCs in tumors, and inhibited the expression of immunosuppressive factors arginase I and iNOS. Consequently, anti-Jagged therapy overcame tumor-induced T-cell tolerance, increased the infiltration of reactive CD8
T cells into tumors, and enhanced the efficacy of T-cell-based immunotherapy. Depletion of MDSC-like cells restored tumor growth in mice treated with anti-Jagged, whereas coinjection of MDSC-like cells from anti-Jagged-treated mice with cancer cells delayed tumor growth. Jagged1/2 was induced in MDSCs by tumor-derived factors via NFkB-p65 signaling, and conditional deletion of NFkB-p65 blocked MDSC function. Collectively, our results offer a preclinical proof of concept for the use of anti-Jagged1/2 to reprogram MDSC-mediated T-cell suppression in tumors, with implications to broadly improve the efficacy of cancer therapy.
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Notch signaling is a well-conserved pathway involved in cell fate decisions, proliferation and apoptosis. We report on the involvement of Notch signaling in regulating gene expression in activated ...macrophages. Toll-like receptors (TLR) agonists such as bacterial lipopeptide, polyI:C, lipopolysaccharide and unmethylated CpG DNA all induced up-regulation of Notch1 in primary and macrophage-like cell lines. Notch1 up-regulation was dependent on the MyD88 pathway when stimulated through TLR2, but not TLR4. Activated Notch1 and expression of the Notch target genes, Hes1 and Deltex, were detected in activated macrophages, suggesting that Notch signaling was activated upon stimulation. Inhibiting processing of Notch receptor by γ-secretase using a γ-secretase inhibitor (GSI), the expression of Notch1 was down-regulated to basal levels. This treatment significantly modulated expression of TNF-α, IL-6, and IL-10. In addition, the amount of nitric oxide produced was significantly lower and the expression of MHC class II was up-regulated in GSI-treated cells. Treatment with GSI or silencing Notch1 resulted in decreased translocation of NF-κBp50 into nucleus upon stimulation. Taken together, stimulation of macrophages through the TLR signaling cascade triggered activation of Notch signaling, which in turn regulated gene expression patterns involved in pro-inflammatory responses, through activation of NF-κB.
Targeted delivery of chemotherapeutic drugs can improve their therapeutic efficiency by localizing their toxic effects at the diseased site. This is often achieved either by direct conjugation of ...drugs to antibodies targeting overexpressed receptors on cancer cells (antibody–drug conjugates/ADCs) or by conjugating antibodies to nanoparticles bearing drugs (antibody–nanoparticle conjugates/ANCs). Here, we report a platform for utilizing hinge cysteines on antigen-binding fragment (Fab′) of an anti-CD4 antibody for site-specific conjugation to nanoparticles giving rise to anti-CD4 Fab′-nanoparticle conjugates (Fab′-NCs). We demonstrate a convenient route for obtaining functional anti-CD4 Fab′ from full-length antibody and examine the targeted delivery efficiencies of anti-CD4 Fab′-NCs vs ANCs for selective delivery to CD4high mT-ALL cells. Our results indicate that higher avidity of full-length anti-CD4 antibody, i.e., protein alone translated to higher binding ability to CD4high mT-ALL cells in comparison with anti-CD4 Fab′ alone. However, the targeted delivery efficiency of anti-CD4 Fab′-NCs was comparable to ANCs indicating that the avidity of Fab′ is restored in a nanoparticle-conjugate format. Fab′-NCs are equally capable of achieving targeted drug delivery to CD4high T-cells as ANCs and are a versatile alternative to ANCs by offering site-selective modification strategy while retaining their advantages.
Notch receptors signaling is required for optimal T-cell activation and function. T-cell receptor (TCR) engagement can activate Notch receptors in T-cells in a ligand-independent fashion. In this ...study, we examined the role of adenosine A2A receptor (A2AR) signaling pathway in regulating the activity of Notch1 induced by TCR stimulation in CD8+T-cells. A selective A2AR agonist decreased Notch1 protein expression and Notch1 cleavage, and reduced transcripts of Notch1-target genes
and
in activated CD8+T-cells. Inhibition of TCR-induced Notch1 expression by an A2AR agonist was accompanied by increased cAMP concentration and mimicked by forskolin. This effect was associated with reduced IFN-γ and granzyme B production. The effect of an A2AR agonist was abrogated by a selective A2AR antagonist and absent in CD8+T-cells harvested from
-/- mice. Stimulation of A2AR reduced Notch1 receptor levels by inhibiting upstream TCR signals, including ZAP70 phosphorylation, in turn impairing the generation of the active Notch1 intracellular domain (N1ICD). Direct activation of PKC with PMA and ionomycin bypassed A2AR-induced Notch1 inhibition. Overexpression of N1ICD in CD8+T-cells prevented the suppressive effects of an A2AR agonist on proliferation and cytokine release during activation. Our results identify the A2AR signaling pathway as an important regulator of TCR-induced Notch1 receptor activation in CD8+T-cells, and Notch as an important target of the immune suppressive effects of A2AR. We propose a mechanism whereby A2AR impairs CD8 T-cells function through inhibition of Notch1 receptor activation.
Macrophages exhibit diverse effector phenotypes depending on the stimuli and their microenvironment. Classically activated macrophages are primed with interferon (IFN)γ and stimulated with ...pathogen-associated molecular patterns. They produce inflammatory mediators and inflammatory cytokines, such as IL-12. In the presence of immune complexes (ICs), activated macrophages have decreased IL-12 production and increased IL-10 production and presumably act as regulatory macrophages. Notch signaling has been shown to regulate the effector functions of classically activated macrophages. In this study, we investigated whether Notch signaling is active in lipopolysaccharide (LPS)-stimulated macrophages in the presence of ICs. LPS/IC stimulation increased the level of cleaved Notch1 in murine macrophages, while IC stimulation alone did not. Delta-like 4, but not Jagged1, was responsible for generating cleaved Notch1. The activation of Notch signaling by LPS/ICs depended upon NF-κB and MEK/Erk pathway activation. Macrophages with the targeted deletion of Rbpj, which encodes a DNA-binding protein central to canonical Notch signaling, produced significantly less IL-10 upon LPS/IC stimulation. A similar impact on IL-10 production was observed when Notch signaling was inhibited with a gamma-secretase inhibitor (GSI). Defects in NF-κB p50 nuclear localization were observed in GSI-treated macrophages and in Rbpj-/- macrophages, suggesting cross-regulation between the Notch and NF-κB pathways. Transcriptomic analysis revealed that Notch signaling regulates the transcription of genes involved in the cell cycle, macrophage activation, leukocyte migration and cytokine production in LPS/IC-stimulated macrophages. Taken together, these results suggest that the Notch signaling pathway plays an important role in regulating the functions of macrophages activated by LPS and ICs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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