Biology subjects

Pedersen, M.

Publications and source records attributed to Pedersen, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Population-specific transcriptional-state remodeling of cortical and hypothalamic neurons in Alzheimer's disease

Selective neuronal vulnerability shapes Alzheimer's disease, but it is commonly inferred from changes in the relative representation of neuronal populations rather than from molecular changes within those populations. We mapped both dimensions across disease progression in amyloid, tau, and combined amyloid-tau mouse models, extended the analysis to cortex and hypothalamus in an independent tau model, and tested the resulting framework in human Alzheimer's disease. Populations with similar reductions in representation showed markedly different degrees of molecular remodeling, while substantial state changes also occurred in populations whose representation remained close to wild type. Disease altered excitability, synaptic, and regulatory programs and reshaped the distribution of cellular states within matched neuronal identities. A particularly recurrent excitatory state linked CAMKK2-AMPK signaling with microtubule regulation. It expanded in glutamatergic populations early in the combined amyloid-tau model, but its direction was not fixed: the same state reversed with age in dentate granule-like neurons and was reduced in corticothalamic neurons of an independent tau model. Remodeling extended beyond cortex to hypothalamic Hdc-positive tuberomammillary neurons, which showed focused excitability-associated changes despite representation close to wild type. In human Alzheimer's disease, remodeling was strongest in several deep-layer and RORB-positive excitatory populations independently associated with vulnerability. The CAMKK2-AMPK-associated state was predominantly reduced rather than increased. An independently defined human depletion-associated neuronal identity instead overlapped other synaptic and calcium-signaling components of the same broader remodeling architecture. Neuronal involvement in Alzheimer's disease is therefore expressed as structured, population-specific remodeling of molecular state, extending across cortical and hypothalamic identities and only partly reflected in relative representation.

neuroscience↗

bioRxiv2026

Multiscale harmonization and semantic integration of biomedical data enable biological insights through immersive exploration

Single-cell atlassing efforts like the Human BioMolecular Atlas Program (HuBMAP) and the Cellular Senescence Network (SenNet) are producing multiscale datasets across the healthy, adult, human body, but this data is typically explored only on 2D screens with limited 3D affordances, even though understanding a cells location within a tissue, organ, and body requires reasoning across many orders of spatial magnitude. The Human Reference Atlas (HRA) provides standard terminologies and a Common Coordinate Framework (CCF) for harmonizing such data spatially and semantically. Building on the HRA Organ Gallery in virtual reality (VR) application, we present "HRA: Powers of Ten," which integrates, harmonizes, and visualizes biological data from these efforts immersively in VR using a Multiscale Elevator System that lets users descend, like riding an elevator through an inverted skyscraper, from a whole body view of 81 reference organs to datasets across 5 organs (lymph node, brain, large intestine, small intestine, liver), 5 assay types (CODEX, Visium, v-CyCIF, Xenium, SBF-SEM), and 4 spatial scales. Contributed by Data Providers, these VR scenes enable biological insights into senescence patterns, cellular neighborhoods, 3D tissue reconstruction, and subcellular liver architecture. A standard operating procedure supports adding further datasets. Freely available on the Meta Store to over 20 million headset owners, the application, data, and code are open-source.

bioinformatics↗

bioRxiv2026

Intratumoural oncolytic HSV-1 reshapes the local and systemic immune landscape through CD8+ T cell reprogramming

Most oncolytic viruses are delivered by intratumoural injection, and local administration can induce regression of both injected and distant tumours in mice and patients. However, the mechanisms by which local viral infection reprograms systemic immunity remain poorly understood. Here we show that intratumoural RP1, an oncolytic HSV-1 encoding GM-CSF and GALV-GP-R-, drives regression of injected and uninjected murine melanoma tumours and prolongs survival. RP1 elicits coordinated CD4 and CD8 T cell infiltration accompanied by local cytokine remodelling, reshaping the immune landscape at both tumour sites. Leveraging the Timer of Cell Kinetics and Activity (Tocky) system and Kaede photoconvertible protein technology, we resolve the temporal dynamics of CD8 T cell responses following local virotherapy and identify two systemically induced, virus-driven CD8 T cell populations distinguished by TCR engagement kinetics: antigen-engaged Timer-positive viral-induced precursors (VIPs) and Timer-negative KLRG1 viral-induced terminal effectors (VITEs). Single-cell transcriptomic and pseudotime analyses reveal divergent differentiation trajectories; VIPs exhibit sustained antigen engagement within the tumour microenvironment (TME), a transcriptional programme associated with self-renewal, and preferential homing to draining lymph nodes. A VIP-associated gene signature correlates with clinical response to RP1 plus PD-1 blockade in the IGNYTE trial of RP1 and nivolumab in PD-1-refractory melanoma and is independently associated with response to immune checkpoint inhibitor (ICI) therapy in melanoma. These findings establish a mechanistic link between local oncolytic virotherapy, systemic CD8 T cell reprogramming, and durable regression of distant lesions in patients.

cancer biology↗

bioRxiv2026

Preclinical efficacy of a systemically-administered, second-generation STING agonist that promotes antitumour immunity in combination with radiotherapy

As potent triggers of innate immunity, STING agonists hold promise as active immunotherapeutic agents for cancer treatment. Second-generation STING agonists, suitable for systemic delivery, are being investigated in preclinical research and have entered clinical trials. Here, the novel synthetic STING agonist, BI-1703880 (STINGa), which was designed for intravenous delivery, was investigated for anti-tumour and immunological effects. We show that STINGa activates the STING pathway and results in a transient and dose-dependent upregulation and secretion of interferons and proinflammatory cytokines in vitro and in vivo. We show that intravenous administration of repeated dosing with low-dose STINGa is well tolerated. We report that radiotherapy (RT) and STING agonism synergizes to generate innate immune cell and CD8+ T cell responses that control tumour growth. Anti-tumour activity induced by combined RT / STINGa was reduced in mice lacking a functional immune system. RT / STINGa combination treatment also initiated development of protective immune memory. RT / STINGa upregulated PD-L1, PD-1 and CTLA-4 in the tumour microenvironment. Our findings show that combining RT / STINGa with immune checkpoint inhibitors further increases therapeutic benefit. Our data confirm STING as a therapeutic target in cancer and support the clinical development of BI-1703880 STING agonist, thereby suggesting radiotherapy as a potential combination for enhancing anti-tumour efficacy.

cancer biology↗

bioRxiv2026

Addition of chemotherapy to radiotherapy promotes progenitor-exhausted CD8⁺ T-cell clonal dominance in head and neck cancer

Concomitant chemoradiotherapy (CRT) is a standard-of-care for unresectable locally-advanced head and neck squamous cell carcinoma (LA-SCCHN), but its immune effects, particularly compared to radiotherapy (RT) alone, remain unclear. Using syngeneic murine models, we integrated Nr4a3-Tocky reporter analysis with single-cell transcriptomics and T-cell receptor clonotyping comprehensively to profile intratumoural CD8 T-cells following RT/CRT. We show that CRT uniquely drives robust antigen-specific clonal expansion and biases differentiation toward progenitor (or precursor) exhausted (TPEX) phenotypes, while RT favours terminal exhaustion (TEX). Single-cell analyses reveal CRT-induced clonal dominance within TPEX subsets, suggesting the potential for enhanced immune reinvigoration. In peripheral blood mononuclear cells (PBMCs) from patients treated with CRT, high levels of TEX cells were found early and at 3 months post-treatment, with delayed peripheral TPEX expansion at 3 months, indicating phased progenitor recovery. These findings demonstrate distinct immunological remodelling by CRT versus RT and underscore the critical importance of treatment timing for optimising combination immunotherapy strategies in LA-SCCHN.

cancer biology↗

bioRxiv2026

Temporal Mechanisms of T-Cell Fate Decisions under Immune Checkpoint Blockade Resolved by CanonicalTockySeq

In cancer immunotherapy, T-cell functional states change dynamically, and no single marker or gene fully defines them. Static molecular profiles may therefore be insufficient to resolve these states. Capturing signalling history together with ongoing activity could provide a temporal framework for their dissection. Here, we developed CanonicalTockySeq, which integrates a molecular clock of T-cell receptor (TCR) signalling based on the Fluorescent Timer reporter Nr4a3-Tocky (Timer-of-cell-kinetics-and-activity) with scRNA-seq to establish an experimentally anchored temporal reference. Using landmark Tocky fractions as biological ground truths, CanonicalTockySeq constructs a transcriptomic manifold in canonical space with conical geometry. In a murine melanoma model treated with combination anti-PD-L1 and anti-CTLA-4, this framework separates temporal progression (geodesic angle) from signalling strength (radial intensity), enabling time-resolved analysis of gene-expression programmes at single-cell resolution. Application to scRNA-seq data from patients with melanoma further identifies distinct temporal programmes associated with clinical response. These analyses indicate that effective combination immunotherapy is associated with decreased persistence of antigen engagement, suppression of exhaustion-associated TCR signalling programmes, and maintenance of progenitor-like features linked to durable antitumour responses. Collectively, our findings identify temporal-state control as a key component of immunotherapy outcome and establish CanonicalTockySeq as a framework for resolving T-cell response states in vivo.

immunology↗

bioRxiv2026

Multilayer Network Modelling of the Human Reading System

Reading is supported by rapid and flexible coordination of neural activity across distributed brain regions. We have previously shown that left fusiform gyrus (FusG) provides a bridge flexibly linking the visual form analysis required for reading with the language system. Here, we investigate the dynamic organisation of an extending reading network encompassing classical perisylvian language areas and FusG. We do so by applying multilayer network modelling to language fMRI data acquired through the Australian Epilepsy Project, using a paradigm that contrasts reading with visuospatial judgements. The dataset included 201 participants with left dominant language, both with and without seizure disorders. We hypothesised that the relative strength of dynamic inter-actions within this extended language network is associated with reading ability. Time resolved functional connectivity was estimated using a sliding window Pearsons correlation approach, and the resulting connectivity matrices were entered into a multilayer community detection algorithm to quantify spatiotemporal community structure within the reading network. We concentrate our analyses on allegiance, the probability that a pair of regions is assigned to the same community over time. Our results show that community structure within the reading network is characterised by a preference for within hemisphere assignment over cross hemisphere assignment, as well as higher nodal allegiance among left language regions compared with their right hemisphere homologues. As anticipated, within versus between network allegiance followed a similar gradient in both language and attention networks: lowest between left language and right attentional regions, intermediate between the left FusG and each respective network, and highest within-network (left language or right attention). Importantly, as hypothesised, reading ability was associated with FusG-inferior frontal gyrus (IFG) interactions: higher left FusG-left IFG allegiance correlated with better reading performance, whereas increased right FusG-left IFG allegiance correlated with poorer reading. These findings highlight hemispheric asymmetries in the dynamic organisation of the reading system and provide novel evidence linking individual differences in reading ability to network level dynamics. Our findings align with a developmental literature suggesting that as reading proficiency improves, there is a shift from bilateral to unilateral left occipitotemporal engagement.

neuroscience↗

bioRxiv2026

Longitudinal Plasma Proteome Changes Before and After Catheter Ablation in Atrial Fibrillation

BackgroundProteins in human plasma serve as critical markers for predicting disease risk and guiding therapeutic development. Current prediction models for atrial fibrillation (AF) largely rely on electronic health records; however, the plasma proteome of patients with AF reflects key biological processes, including inflammation, that are not captured by clinical variables alone. Circulating inflammatory mediators contribute to electrical and structural remodelling in the atria, thereby sustaining the AF phenotype. Identification of plasma proteins associated with AF may therefore improve understanding of the inflammatory and other biological processes underlying AF pathophysiology. ObjectiveIn this study, we profiled the plasma proteome of patients with paroxysmal AF (pxAF), persistent AF (persAF), and non-AF controls using Olink assay technology. MethodsPlasma samples from 30 individuals were analysed with the Olink Reveal panel. Differential expression analysis of normalised protein expression (NPX) values was performed between groups, with differentially expressed proteins (DEPs) defined by P < 0.05. ResultsWe identified 87 DEPs in pxAF and 107 DEPs in persAF compared with controls. From these, we shortlisted 11 candidate proteins that were upregulated in persAF at baseline and showed reduced expression 12 months after catheter ablation. This subset of proteins is implicated in the regulation of inflammation (CCL23, CXCL10, IL33), metabolism (ALDH3A1, NDUFS6), cell-matrix adhesion (AFAP1L1, LGALS7, SPOCK1), and physiological signalling (NOS1, PROK1, PTH). ConclusionCollectively, these plasma proteins highlight systemic molecular mechanisms contributing to AF pathogenesis and represent potential AF-specific biomarkers warranting further investigation in larger clinical cohorts and mechanistic studies.

molecular biology↗

bioRxiv2025

Aromatic lactic acid production by Bifidobacterium longum subsp. infantis is determined by cell density, substrate availability and pH in vitro

Bifidobacterium longum subsp. infantis (B. infantis) is an important colonizer of the infant gut. This species is known to produce a variety of health beneficial metabolites, including aromatic lactic acids (ALAs), supporting early life immune development. However, the regulation of ALA production in B. infantis remains poorly understood. In this study, we investigated how environmental factors, such as substrate availability and pH affect B. infantis DSM20088 growth and ALA production in vitro. Bacterial batch cultivations supplemented with different amino acid concentrations revealed a linear relationship between indole-3-lactic acid (ILA), 4-hydroxyphenyllactic acid (OH-PLA), and phenyllactic acid (PLA) production and exogenous concentrations of tryptophan, tyrosine and phenylalanine, respectively. Furthermore, chemostat cultivations at physiological relevant pH levels (4.5, 5.5 and 6.5) showed that an acidic pH slowed growth and shifted ALA production by B. infantis. Overall, ALA concentrations correlated strongly with bacterial abundance across and within pH levels, showing that cell density is a major determinant of ALA production. After considering the growth limiting effects of lower environmental pH, it had limited impact on the total production of ALAs, but the relative production of PLA was stepwise enhanced at more acidic pH at the expense of ILA, independent of cell density. In conclusion, this study shows that cell density, substrate availability and environmental pH determine aromatic lactic acid production by B. infantis. ImportanceBifidobacterium longum subsp. infantis is an abundant bacterial species in the infant gut microbiota where it supports immune development e.g. though the production of aromatic lactic acids. In this study we cultured Bifidobacterium longum subsp. infantis at different concentrations of aromatic amino acids and pH levels to investigate the effect of these environmental factors on aromatic lactic acid production. We show that there is a linear relationship between aromatic lactic acid production and the exogenous aromatic amino acid concentration, that the production strongly follows cell density, and that pH regulates the preference towards producing different aromatic lactic acids. This knowledge may help inform strategies to enhance or direct beneficial ALA production in the infant gut.

microbiology↗

bioRxiv2025

Rapid expansion of podoplanin-positive fibroblasts following radiation limits the anti-tumour CD8+ T-cell response to radiotherapy.

Radiotherapy is known to cause changes in the tumour stroma which can undermine treatment efficacy. Our understanding of this process has historically centred around effects driven by Transforming Growth Factor-beta (TGF-{beta}) and alpha-smooth muscle actin (-SMA)+ fibroblasts. Here, we identified a rapid expansion of podoplanin (PDPN)+ fibroblasts following radiotherapy in breast, head and neck and melanoma tumours. This fibrosis was not dependent on TGF-{beta}, but was downstream of a radiotherapy-induced adaptive immune response. CD8+ T-cells entering the tumour after radiation were sequestered at the interface between residual tumour cells and PDPN+ fibroblasts and failed to enter the tumour core. Genetic deletion of PDPN in fibroblasts impacted their cytoskeleton and ability to organise extracellular matrix. This was associated with increased CD8+ T-cell entry and spontaneous tumour regression. Overall, we identify a mechanism whereby PDPN+ fibrosis limits immune-mediated radiation cell kill and demonstrate that disruption of PDPN signalling favours tumour control. SignificanceIn this study we show that rapid podoplanin (PDPN)+ fibroblast expansion following radiotherapy limits immune-mediated radiation cell kill. Targeting PDPN and associated downstream signalling improves tumour control and is a promising strategy in combination with radiotherapy. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=175 SRC="FIGDIR/small/680949v1_ufig1.gif" ALT="Figure 1"> View larger version (61K): org.highwire.dtl.DTLVardef@1711bb0org.highwire.dtl.DTLVardef@d0c3a1org.highwire.dtl.DTLVardef@1db88adorg.highwire.dtl.DTLVardef@1ea3ab6_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2025

ARID1A stabilises non-homologous end joining factors at DNA breaks induced by the G4 ligand pyridostatin

ARID1A is a subunit of the BAF chromatin remodelling complex that is frequently mutated in cancer. It is challenging to predict how ARID1A loss impacts cancer therapy response because it participates in many different cellular pathways. G quadruplex (G4) binding ligands, such as pyridostatin, have shown anticancer effects, but the pathways and genetic determinants involved in the response to G4 ligands are still not fully understood. Here, we show that ARID1A deficient cells are selectively sensitive to pyridostatin when compared with isogenic controls. Sensitivity to pyridostatin was apparent in ovarian and colorectal cancer cell line models, and in vivo studies suggest that G4 ligands hold promise for treating ARID1A deficient cancers. While we find that ARID1A impacts on pyridostatin-induced transcriptional responses, we find that pyridostatin-mediated toxicity in ARID1A-deficient cells is driven by defective DNA repair of topoisomerase-induced breaks. We show that ARID1A-deficient cells are unable to efficiently accumulate non-homologous end joining proteins on chromatin following pyridostatin exposure. These data uncover a role for ARID1A in the cellular response to G4 ligands, and link remodelling to G4 ligand-induced transcriptional and DNA damage responses.

molecular biology↗

bioRxiv2025

Uncovering the Signatures of Cellular Senescence in the Human Dorsolateral Prefrontal Cortex

Identifying senescent cells poses challenges due to their rarity, heterogeneity, and lack of a definitive marker. We performed Visium spatial transcriptomics (ST) and single nucleus RNA sequencing (snRNA-seq) on non-pathological human tissue to build a transcriptomic atlas of aging and senescence in the dorsolateral prefrontal cortex (dlPFC). We identified markers characteristic of aging dlPFC cortical layers and cell types. We also observed an increase in astrocyte abundance and decrease in somatostatin expressing inhibitory neurons. Overall, the senescence profile in the dlPFC was highly heterogeneous and heavily influenced by cell type identity and cortical layer. Combined unbiased analysis of ST and snRNA-seq datasets revealed gene expression modules encoding for communities of microglia and endothelial cells in the white matter and regional astrocytes programs that were strongly enriched with age and for senescence-related genes. These findings will help facilitate future studies exploring the function of senescent cell subpopulations in the aging brain.

cell biology↗

bioRxiv2024

Silk-Ovarioids: Establishment and characterization of human ovarian primary cells 3D-model system

In vitro models that mimic ovaries are crucial for elucidating the biological mechanisms underlying follicle activation and growth. Three-dimensional (3D) systems are particularly relevant because they can replicate the heterogeneity and cell-cell communication between different ovarian cell types. However, complex models using human ovarian primary cells have not yet been established. In this study, we developed and characterized long-term cultured 3D models of primary ovarian somatic cells isolated from adult tissues, using Biosilk as a scaffold. We successfully established both ovarian cortex- and medulla-derived 3D systems, termed Silk-Ovarioids. The presence of key ovarian somatic cell types - including granulosa, stromal, endothelial, and perivascular cells - was confirmed by transcriptomics, proteomics, and immunostaining. Notably, Silk-Ovarioids exhibited the formation of a pro-angiogenic hypoxic core, as evidenced by the development of vessel-like structures after six weeks of culture. The Silk-Ovarioids demonstrated low intra-batch variability and long-term culture stability, underscoring their potential as a robust step towards creating a bioengineered, patient-specific artificial ovary.

cell biology↗

bioRxiv2024

National-scale acoustic monitoring of avian biodiversity and phenology

Billions of birds migrate annually, triggered by endogenous behaviors but also by ecoclimatic drivers which are shifting with climate change. These dynamics play out over huge spatiotemporal scales, making monitoring of phenology challenging with traditional biodiversity survey approaches. In this study, over a complete spring migration season (April through June), we collected 37,429 hours of audio from 28 networked sensors in forests across Norway using a nationwide passive acoustic monitoring (PAM) system. We applied an open-source detection algorithm to automatically classify bird vocalizations; through expert validation we found the algorithm classified 57 species (14 full migrants) with at least 80% precision. Using these automated detections, we developed regional arrival curves for three common migratory passerines: Willow Warbler, Common Chiffchaff, and Spotted Flycatcher. We then demonstrate that PAM detections can be used to train audio species distribution models that map how species vocalization probability changes across Norway during spring migration. Lastly, we discuss how PAM can complement existing manual surveys to support the design and implementation of effective policy and conservation measures.

ecology↗

bioRxiv2024

Combination of oncolytic Maraba virus with immune checkpoint blockade overcomes therapy resistance in an immunologically cold model of advanced melanoma with dysfunctional T cell receptor signalling.

BackgroundOver the past decade, cancer immunotherapies have revolutionised the treatment of melanoma; however, responses vary across patient populations. Recently, baseline tumour size has been identified as an independent prognostic factor for overall survival in melanoma patients receiving immune checkpoint inhibitors (ICIs). MG1 is a novel oncolytic agent with broad tumour tropism that has recently entered early phase clinical trials. The aim of this study was to characterise T cell responses in human and mouse melanoma models following MG1 treatment and to establish if features of the tumour immune microenvironment (TIME) at two distinct tumour burdens would impact the efficacy of oncolytic virotherapy. MethodsHuman 3D in vitro priming assays were performed to measure anti-tumour and anti-viral T cell responses following MG1 infection. TCR sequencing, T2 killing assay, and peptide recall assays were used to assess the evolution of the TCR repertoire, and measure specific T cell responses, respectively. In vivo, subcutaneous 4434 melanomas were characterised using RNAseq, immunohistochemistry (IHC), and flow cytometry. The effectiveness of intra-tumoural MG1 was assessed in advancing 4434 tumours and the generation of anti-tumour and anti-viral T cells measured by splenocyte recall assays. Finally, combination MG1 and -PD-1 therapy was investigated in advanced 4434 tumours. ResultsMG1 effectively primed functional cytotoxic T cells (CTLs) against tumour associated antigens (TAA) as well as virus-derived peptides, as assessed using peptide recall and T2 killing assays, respectively. TCR sequencing revealed that MG1-primed CTL comprised larger clusters of similar CDR3 amino acid sequences compared to controls. In vivo testing of MG1 demonstrated that MG1 monotherapy was highly effective at treating early disease, resulting in 90% cures; however, the efficacy of MG1 reduced as the disease burden (local tumour size) increased, and the addition of -PD-1 was required to overcome resistance in more advanced disease. Differential gene expression profiles revealed that increased tumour burden was associated with an immunologically colder TIME. Furthermore, analysis of TCR signalling in advancing tumours demonstrated a different dynamic of TCR engagement compared to smaller tumours, in particular a shift in antigen recognition by CD4+ cells, from conventional to regulatory subset. ConclusionCombination of MG1 with PD-1 overcomes therapy resistance in an immunologically cold model of advanced melanoma.

cancer biology↗

bioRxiv2024

Estimating Directed Connectivity with OPM-MEG: A Feasibility Study

We explored the directed connectivity of magnetoencephalography data recorded via Optically Pumped Magnetometers (OPM-MEG). Ten healthy adult participants were scanned twice while watching a movie in an OPM-MEG system. Beamformer source localisation was employed to obtain source time series within 62 cortical brain regions. Multivariate transfer entropy (mTE) was used to quantify directed connectivity. Our results suggest that out-degree connectivity (node-to-network) was stronger than in-degree (network-to-node). Out-degree display a more heavy-tailed distribution, indicative of brain hubs, whereas in-degree nodes had a distribution closer to a normal distribution. Although in-degree and out-degree nodes were positively correlated, we observed that out-degree connectivity was stronger in somatomotor and attention networks than in other resting-state networks. However, in- and out-degree were both inversely related to the physical distance between nodes, suggesting that directed connectivity is stronger between short-distanced nodes. As OPM-MEG research is likely to expand substantially in the future, we propose that directed connectivity measures may provide additional insights into the underlying mechanisms of brain communication.

neuroscience↗

bioRxiv2024

Investigating the ability of music to induce calm in young adults.

Withdrawal StatementThe authors have withdrawn their manuscript owing to reviewer feedback. A revised version of this work will be uploaded with significant changes. Therefore, the authors do not wish this work to be cited as a reference for the project. If you have any questions, please contact the corresponding author.

neuroscience↗

bioRxiv2023

PARP inhibitors enhance reovirus-mediated cell killing through the death-inducing signaling complex (DISC) with an associated NF-kappa B-regulated immune response.

Oncolytic Reovirus type 3 Dearing (RT3D), is a naturally occurring double-stranded (ds) RNA virus that is under development as an oncolytic immunotherapy We used an unbiased high-throughput cytotoxicity screen of different targeted therapeutic agents with the aim of identifying potential drug-viral sensitizers to enhance RT3D tumour killing. Talazoparib, a clinical poly(ADP)-ribose polymerase 1 (PARP-1) inhibitor, was identified as a top hit and found to cause profound sensitisation to RT3D. This effect was not seen with other classes of oncolytic virus and was not mediated by enhanced viral replication or PARP inhibitor-related effects on the DNA damage response. RT3D interacts with retinoic acid-induced gene-1 (RIG-I) and activates PARP-1, with consequent PARylation of components of the extrinsic apoptosis pathway. Pharmacological and genetic inhibition of PARP-1 abrogates this PARylation and increases levels of extrinsic apoptosis, NF-kB signalling and pro-inflammatory cell death. Direct interaction between PARP-1 and RIG-I following RT3D/talazoparib treatment is a key factor in activating downstream signaling pathways that lead to IFN-{beta} and TNF-/TRAIL production which, in turn, amplify the therapeutic effect through positive feedback. Critically, it was possible to phenocopy the effect of RT3D through the use of non-viral ds-RNA therapy and RIG-I agonism. In in vivo studies, we demonstrated profound combinatorial efficacy of RT3D and talazoparib in human A375 melanoma in immunodeficient mice. More impressively, in immunocompetent mouse models of 4434 murine melanoma, we achieved 100% tumour control and protection from subsequent tumour rechallenge with the combination regimen. Correlative immunophenotyping confirmed significant innate and adaptive immune activation with the combination of RT3D and PARP inhibition. Taken together, these data provide a clear line of sight to clinical translation of combined regimens of PARP inhibition or ds-RNA agonism, with either viral or non-viral agents, in tumour types beyond the relatively narrow confines of current licensed indications for PARP inhibition.

cancer biology↗