Cannabinoids reduce melanoma cell viability and do not interfere with commonly used targeted therapy in metastatic melanoma in vivo and in vitro

Background: Cannabinoids are mainly used for recreational purposes, but also made their way into oncology, since these substances can be taken to increase appetite in tumour cachexia. Since there are some hints in the literature that cannabinoids might have some anti-cancerous effects, the aim of this study was to study if and how cannabinoids mediate pro-apoptotic effects in metastatic melanoma in vivo and in vitro and its value besides conventional targeted therapy in vivo. Methods: Several melanoma cell lines were treated with different concentrations of cannabinoids, and anti-cancerous efficacy was assessed by proliferation and apoptosis assays. Subsequent pathway analysis was performed using apoptosis, proliferation, flow cytometry and confocal microscopy data. The efficacy of cannabinoids in combination with trametinib was studied in NSG mice in vivo. Results: Cannabinoids reduced cell viability in multiple melanoma cell lines in a dose-dependent way. The effect was mediated by CB1, TRPV1 and PPARα receptors, whereby pharmacological blockade of all three receptors protected from cannabinoid-induced apoptosis. Cannabinoids initiated apoptosis by mitochondrial cytochrome c release with consecutive activation of different caspases. Essentially, cannabinoids significantly decreased tumour growth in vivo and were as potent as the MEK inhibitor trametinib. Conclusions: We could demonstrate that cannabinoids reduce cell viability in several melanoma cell lines, initiate apoptosis via the intrinsic apoptotic pathway by cytochrome c release and caspase activation and do not interfere with commonly used targeted therapy

Myelin repair in vivo is increased by targeting oligodendrocyte precursor cells with nanoparticles encapsulating leukaemia inhibitory factor (LIF)

AbstractMultiple sclerosis (MS) is a progressive demyelinating disease of the central nervous system (CNS). Many nerve axons are insulated by a myelin sheath and their demyelination not only prevents saltatory electrical signal conduction along the axons but also removes their metabolic support leading to irreversible neurodegeneration, which currently is untreatable. There is much interest in potential therapeutics that promote remyelination and here we explore use of leukaemia inhibitory factor (LIF), a cytokine known to play a key regulatory role in self-tolerant immunity and recently identified as a pro-myelination factor. In this study, we tested a nanoparticle-based strategy for targeted delivery of LIF to oligodendrocyte precursor cells (OPC) to promote their differentiation into mature oligodendrocytes able to repair myelin. Poly(lactic-co-glycolic acid)-based nanoparticles of ∼120 nm diameter were constructed with LIF as cargo (LIF-NP) with surface antibodies against NG-2 chondroitin sulfate proteoglycan, expressed on OPC. In vitro, NG2-targeted LIF-NP bound to OPCs, activated pSTAT-3 signalling and induced OPC differentiation into mature oligodendrocytes. In vivo, using a model of focal CNS demyelination, we show that NG2-targeted LIF-NP increased myelin repair, both at the level of increased number of myelinated axons, and increased thickness of myelin per axon. Potency was high: a single NP dose delivering picomolar quantities of LIF is sufficient to increase remyelination.Impact statementNanotherapy-based delivery of leukaemia inhibitory factor (LIF) directly to OPCs proved to be highly potent in promoting myelin repair in vivo: this delivery strategy introduces a novel approach to delivering drugs or biologics targeted to myelin repair in diseases such as MS

Monocytes and Macrophages Serve as Potent Prostaglandin D2 Sources during Acute, Non-Allergic Pulmonary Inflammation

Acute respiratory inflammation, most commonly resulting from bacterial or viral infection, is one of the leading causes of death and disability worldwide. The inflammatory lipid mediator prostaglandin D2 (PGD2) and its rate-limiting enzyme, hematopoietic PGD synthase (hPGDS), are well-known drivers of allergic pulmonary inflammation. Here, we sought to investigate the source and role of hPGDS-derived PGD2 in acute pulmonary inflammation. Murine bronchoalveolar monocytes/macrophages from LPS- but not OVA-induced lung inflammation released significant amounts of PGD2. Accordingly, human monocyte-derived macrophages expressed high basal levels of hPGDS and released significant levels of PGD2 after LPS/IFN-γ, but not IL-4 stimulation. Human peripheral blood monocytes secreted significantly more PGD2 than monocyte-derived macrophages. Using human precision-cut lung slices (PCLS), we observed that LPS/IFN-γ but not IL-4/IL-13 drive PGD2 production in the lung. HPGDS inhibition prevented LPS-induced PGD2 release by human monocyte-derived macrophages and PCLS. As a result of hPGDS inhibition, less TNF-α, IL-6 and IL-10 could be determined in PCLS-conditioned medium. Collectively, this dataset reflects the time-dependent release of PGD2 by human phagocytes, highlights the importance of monocytes and macrophages as PGD2 sources and suggests that hPGDS inhibition might be a potential therapeutic option for acute, non-allergic lung inflammation

Therapeutic Potential of Hematopoietic Prostaglandin D2 Synthase in Allergic Inflammation

Worldwide, there is a rise in the prevalence of allergic diseases, and novel efficient therapeutic approaches are still needed to alleviate disease burden. Prostaglandin D2 (PGD2) has emerged as a central inflammatory lipid mediator associated with increased migration, activation and survival of leukocytes in various allergy-associated disorders. In the periphery, the hematopoietic PGD synthase (hPGDS) acts downstream of the arachidonic acid/COX pathway catalysing the isomerisation of PGH2 to PGD2, which makes it an interesting target to treat allergic inflammation. Although much effort has been put into developing efficient hPGDS inhibitors, no compound has made it to the market yet, which indicates that more light needs to be shed on potential PGD2 sources and targets to determine which particular condition and patient will benefit most and thereby improve therapeutic efficacy. In this review, we want to revisit current knowledge about hPGDS function, expression in allergy-associated cell types and their contribution to PGD2 levels as well as beneficial effects of hPGDS inhibition in allergic asthma, rhinitis, atopic dermatitis, food allergy, gastrointestinal allergic disorders and anaphylaxis

Targeting the P2Y13 Receptor Suppresses IL-33 and HMGB1 Release and Ameliorates Experimental Asthma

Rationale: The alarmins IL-33 and HMGB1 (high mobility group box 1) contribute to type 2 inflammation and asthma pathogenesis. Objectives: To determine whether P2Y13-R (P2Y13 receptor), a purinergic GPCR (G protein–coupled receptor) and risk allele for asthma, regulates the release of IL-33 and HMGB1. Methods: Bronchial biopsy specimens were obtained from healthy subjects and subjects with asthma. Primary human airway epithelial cells (AECs), primary mouse AECs, or C57Bl/6 mice were inoculated with various aeroallergens or respiratory viruses, and the nuclear-to-cytoplasmic translocation and release of alarmins was measured by using immunohistochemistry and an ELISA. The role of P2Y13-R in AEC function and in the onset, progression, and exacerbation of experimental asthma was assessed by using pharmacological antagonists and mice with P2Y13-R gene deletion. Measurements and Main Results: Aeroallergen exposure induced the extracellular release of ADP and ATP, nucleotides that activate P2Y13-R. ATP, ADP, and aeroallergen (house dust mite, cockroach, or Alternaria antigen) or virus exposure induced the nuclear-to-cytoplasmic translocation and subsequent release of IL-33 and HMGB1, and this response was ablated by genetic deletion or pharmacological antagonism of P2Y13. In mice, prophylactic or therapeutic P2Y13-R blockade attenuated asthma onset and, critically, ablated the severity of a rhinovirusassociated exacerbation in a high-fidelity experimental model of chronic asthma. Moreover, P2Y13-R antagonism derepressed antiviral immunity, increasing IFN-l production and decreasing viral copies in the lung. Conclusions: We identify P2Y13-R as a novel gatekeeper of the nuclear alarmins IL-33 and HMGB1 and demonstrate that the targeting of this GPCR via genetic deletion or treatment with a small-molecule antagonist protects against the onset and exacerbations of experimental asthma.</p