Biology subjects

Muir, M.

Publications and source records attributed to Muir, M..

16 recordsLinked to original sources

bioRxiv2026

FAK Inhibition Remodels the Metastatic ECM and Restores CD8+ T Cell Trafficking and Immunosurveillance

Metastatic breast cancer remains largely incurable, driven in part by immunosuppressive microenvironments that limit CD8+ T cell-mediated clearance. Using a murine pulmonary metastatic breast cancer model, we show that the focal adhesion kinase (FAK) inhibitor VS-4718 promotes a CD8+ T cell-dependent regression of metastatic lesions by reprograming the metastatic microenvironment. VS-4718 reduced immunosuppressive myeloid and regulatory T cells while increasing CD8+ T cell infiltration. Cellular and secreted proteome profiling revealed that VS-4718 downregulates ECM components such as laminin 5 and collagen VIII1, which we show impair CD8+ T cell migration and activity. In human breast cancer cohorts, elevated LAMA5/COL8A1 expression and a FAK-dependent ECM signature associate with poor outcome and prognostic for residual disease. Intravital imaging demonstrated that VS-4718 enhances CD8 T cell extravasation and induces T cell-tumor cell contacts necessary for cytotoxicity. Ex vivo lung slice cultures recapitulated these findings, showing enhanced T cell swarming, metastatic cluster shrinkage, and apoptosis. These findings reveal how FAK inhibition remodels the metastatic ECM to potentiate coordinated CD8+ T cell responses. VS-4718 might aid in clearing metastases in breast cancer patients through modulating both stromal and immune components. STATEMENT OF SIGNIFICANCEFocal adhesion kinase (FAK) inhibition remodels collagen- and laminin-rich extracellular matrix barriers and alleviates physical constraints that limit CD8 T cell access and activity in metastases. This enhances infiltration, migration, and tumor cell engagement, and synergizes with PD-1 blockade, supporting combined therapeutic strategies in metastatic breast cancer.

cancer biology↗

bioRxiv2025

FAK inhibitor treatment systemically regulates the glioblastoma immune environment via blocking monocyte trafficking

Glioblastoma (GBM) is the most common primary malignant brain tumour in adults with dismal survival rates, and current therapies, including most immunotherapies, are not efficacious due to the highly immunosuppressive microenvironment. Studies in other solid cancers report that impairment of the integrin effector pathway involving focal adhesion kinase (FAK) can promote anti-tumour immune responses. Therefore, we set out to address whether, and if so how, suppressing FAK function may influence GBM by using both tumour cell-specific FAK gene deletion and systemic delivery of a clinically relevant FAK kinase inhibitor (FAKi) VS-4718 in an orthotopic murine stem cell model of GBM. We found that treatment with the FAKi, but not tumour cell-specific FAK gene deletion, resulted in GBM clearance and improved survival. This was dependent on adaptive immunity, and tumour-infiltrating T cells in FAKi-treated tumours displayed increased cytotoxic potential and reduced exhaustion. We also found a significant reduction in immuno-suppressive peripherally-derived macrophages and FAKi treatment caused sequestration of inflammatory monocytes within the bone marrow, resulting in impaired monocyte trafficking to tumours as judged by adoptive transfer. This is due to suppression of key adhesion and migration signalling through 4{beta}1 integrin and CX3CR1 in peripheral monocytes. Our work here describes a previously unidentified role for FAK in trafficking of peripheral suppressive macrophages to GBM tumours, reducing T cell exhaustion and promoting anti-tumour immunity. This highlights a new way in which systemic FAK inhibitors can be used to provide a beneficial immune modulatory strategy for the treatment of GBM.

immunology↗

bioRxiv2025

Dysproteostasis primes pancreatic epithelial state changes in KRAS-mediated oncogenesis

Pre-malignant transformation of pancreatic acinar cells by oncogenic Kras is dependent upon stochastic emergence of metaplastic cell states, through unknown mechanisms. We reveal that an early, transcriptionally-mediated effect of Kras is sporadic failure of proteostatic ER-phagy. Genetically-altered mice deficient in ER-phagy demonstrate that this event co-operates with Kras to drive acinar-ductal metaplasia (ADM) and subsequent cancer. Mechanistically, proteomics and high-resolution imaging uncover pathologic aggregation of a subset of ER proteins, including the injury marker REG3B, resulting from failure to physically interact with the ER-phagy receptor CCPG1. Spatial transcriptomics demonstrate that the appearance of sporadic intracellular aggregates upon Kras activation marks rare acinar cells existing in an injured, ADM-primed state. Importantly, engineered mutants of REG3B establish that aggregate formation is sufficient to directly engender this epithelial cell state. Pancreatic cancer can thus arise from stochastic pathologic protein aggregates that are influenced by and co-operate with an oncogene.

cancer biology↗

bioRxiv2024

Non-Invasive Brain Mapping Localizes Essential Language Function in Surgical Glioma Patients

IntroductionGlioma patients with tumors near critical language regions present significant clinical challenges. Surgeons often lack the tools to understand how each unique surgical approach may impact linguistic ability, leading to subjective decisions and unpredictable outcomes. ObjectiveWe aim to develop an approach that uses data-driven preoperative brain mapping to quantitatively predict the impact of planned resections on long-term language function. MethodsThis study included 79 consecutive patients undergoing resection of language-eloquent gliomas. Patients underwent preoperative navigated transcranial magnetic stimulation (nTMS) language mapping to identify language-positive sites ("TMS points") and their associated white matter tracts ("TMS tracts") as well as formal language evaluations pre and postoperatively. The resection of regions identified by preoperative mapping was correlated with persistent postoperative language deficits (PLDs). ResultsThe resection of TMS points did not predict PLDs. However, a TMS point subgroup defined by white matter connectivity significantly predicted PLDs (OR=8.74, p<.01) and exhibited a canonical group-level anatomical distribution of cortical language sites. TMS-derived tracts recapitulated normative group-level patterns of white matter connectivity defined by the Human Connectome Project (HCP). Subcortical resection of TMS tracts predicted PLDs independently of cortical resection (OR=60, p<.001). The resected TMS tract segments in patients with PLDs co-localized with normative, language-associated subcortical pathways, in contrast to the resected TMS tract segments in non-aphasic patients (p<.05). Accordingly, resecting patient- specific co-localizations between TMS tracts and normative tracts in native space predicted PLDs with an accuracy of 94% (OR=134, p<.001). Co-localization between individualized and normative tracts precisely predicted the linguistic performance of a patient intraoperatively in response to direct electrophysiological stimulation of subcortical brain. ConclusionThis study outlines a data-driven brain mapping approach that provides surgical insight by preoperatively predicting the impact of individual glioma resection on long-term language function. Key PointsO_LIWhite matter connectivity determines the long-term functionality of cortical language sites mapped by TMS. C_LIO_LILong-term deficits in language processing result from resecting individualized subcortical regions within language-associated white matter tracts. C_LIO_LINon-invasive TMS language mapping combined with routine preoperative imaging can predict language outcomes of individual surgical approaches with an accuracy of 94%. C_LI

neuroscience↗

bioRxiv2023

Multidimensional proteomics identifies molecular trajectories of cellular aging and rejuvenation

The declining capacity of cells to maintain a functional proteome is a major driver of cellular dysfunction and decreased fitness in aging. Here we assess the impact of aging on multiple proteome dimensions, which are reflective of function, across the replicative lifespan of Saccharomyces cerevisiae. We quantified protein abundance, protein turnover, protein thermal stability, and protein phosphorylation in mother yeast cells and their derived progeny at different ages. We find progressive and cumulative proteomic alterations that are reflective of dysregulation of complex assemblies, mitochondrial remodeling, post-translational activation of the AMPK/Snf1 energy sensor in mother cells, and an overall shift from biosynthetic to energy-metabolic processes. Our multidimensional proteomic study systematically corroborates previous findings of asymmetric segregation and daughter cell rejuvenation, and extends these concepts to protein complexes, protein phosphorylation, and activation of signaling pathways. Lastly, profiling age-dependent proteome changes in a caloric restriction model of yeast provided mechanistic insights into longevity, revealing minimal remodeling of energy-metabolic pathways, improved mitochondrial maintenance, ameliorated protein biogenesis, and decreased stress responses. Taken together, our study provides thousands of age-dependent molecular events that can be used to gain a holistic understanding of mechanisms of aging.

systems biology↗

bioRxiv2022

Evidence that conserved essential genes are enriched for pro-longevity factors

At the cellular level, many aspects of aging are conserved across species. This has been demonstrated by numerous studies in simple model organisms like Saccharomyces cerevisiae, Caenorhabdits elegans, and Drosophila melanogaster. Because most genetic screens examine loss of function mutations or decreased expression of genes through reverse genetics, essential genes have often been overlooked as potential modulators of the aging process. By taking the approach of increasing the expression level of a subset of conserved essential genes, we found that 25% of these genes resulted in increased replicative lifespan in S. cerevisiae. This is greater than the [~]3.5% of genes found to affect lifespan upon deletion, suggesting that activation of essential genes may have a relatively disproportionate effect on increasing lifespan. The results of our experiments demonstrate that essential gene overexpression is a rich, relatively unexplored means of increasing eukaryotic lifespan.

cell biology↗

bioRxiv2022

Loss of the adhesion protein Kindlin-1 stimulates tumor clearance via modulation of Tregs

The adhesion protein Kindlin-1 is over-expressed in breast cancer where it has been shown to be associated with metastasis-free survival, however, the mechanisms involved are poorly understood. Here, we report that Kindlin-1 promotes anti-tumor immune evasion in a mouse model of breast cancer. Deletion of Kindlin-1 in Met-1 mammary tumor cells leads to tumor regression following injection into immunocompetent hosts. This was associated with a reduction in tumor infiltrating Tregs and impairment of their immune-suppressive activities in Kindlin-1 depleted tumors. Similar changes in T cell populations were seen following depletion of Kindlin-1 in the polyomavirus middle T antigen (PyV MT)-driven mouse model of mammary tumorigenesis. Analysis of cytokines secreted from the Met-1 cells identified a significant increase in IL-6 secretion when Kindlin-1 was depleted. Conditioned media from Kindlin-1 depleted cells lead to a decrease in the ability of Tregs to suppress the proliferation of CD8+ T cells, which was dependent on IL-6 and depletion of CD25+ Tregs resulted in a reduction of Met-1 tumor growth in mice. Overall, these data identify a novel function for Kindlin-1 in the regulation of anti-tumor immunity through cytokine regulation of Treg number and function.

cancer biology↗

bioRxiv2022

Deficiency of the RNA-binding protein Cth2 extends yeast replicative lifespan by alleviating its repressive effects on mitochondrial function

Iron dyshomeostasis contributes to aging, but little information is available about the molecular mechanisms. Here, we provide evidence that, in Saccharomyces cerevisiae, aging is associated with altered expression of genes involved in iron homeostasis. We further demonstrate that defects in the conserved mRNA-binding protein Cth2, which controls stability and translation of mRNAs encoding iron-containing proteins, increase lifespan by alleviating its repressive effects on mitochondrial function. Mutation of the conserved cysteine residue in Cth2 that inhibits its RNA-binding activity is sufficient to confer longevity, whereas Cth2 gain-of-function shortens replicative lifespan. Consistent with its function in RNA degradation, we demonstrate that Cth2 deficiency relieves Cth2-mediated post-transcriptional repression of nuclear-encoded components of the electron transport chain. Our findings uncover a major role of the RNA-binding protein Cth2 in the regulation of lifespan and suggest that modulation of iron starvation signaling can serve as a target for potential aging interventions.

genomics↗

bioRxiv2021

Pathway profiling of a novel SRC inhibitor, AZD0424, in combination with MEK inhibitors.

A more comprehensive understanding of how cells respond to drug intervention, the likely immediate signalling responses and how resistance may develop within different microenvironments allows us anticipate how cells adapt to targeted therapy enabling more informed prediction of rational drug combinations. The non-receptor tyrosine kinase SRC regulates many cellular signalling processes and pharmacological inhibition has long been a target of drug discovery projects for the treatment of cancer. Here we describe the in vitro and in vivo characterisation of the small molecule SRC inhibitor, AZD0424. We show that AZD0424 potently inhibits the phosphorylation of tyrosine-416 of SRC (IC50 [~] 100 nM) in many cancer cell lines; however inhibition of cell viability, via a G1 cell cycle arrest, was observed only in a sub-set of cancer cell lines in the low (on target) micromolar range. We profiled the changes in intracellular pathway signalling in cancer cells following exposure to AZD0424 and other targeted therapies using Reverse Phase Protein Array analysis. We demonstrate that SRC is activated in response to MEK inhibitor (trametinib or AZD6244)-treatment of KRAS mutant colorectal cell lines (HCT116 and DLD1) and that AZD0424 abrogates this. Cell lines treated with trametinib or AZD6244 in combination with AZD0424 revealed reduction of EGFR, FAK and SRC compensatory activation, and, synergistically inhibits cell viability in vitro. In vivo, trametinib-treatment of mice bearing HCT116 tumours increased phosphorylation of SRC on Tyr416, and when combined with AZD0424, inhibition of tumour growth is greater than trametinib alone. We also demonstrate that drug-induced resistance to trametinib is not re-sensitised by AZD0424 treatment in vitro, likely as a result of multiple compensatory signalling mechanisms; however inhibition of SRC remains an effective way to block invasion of trametinib resistant tumour cells. These data imply that inhibiting SRC may offer a useful addition to MEK inhibitor combination strategies.

cancer biology↗

bioRxiv2021

11β-HSD1 inhibition does not affect murine tumour angiogenesis but may exert a selective effect on tumour growth by modulating inflammation and fibrosis

Glucocorticoids inhibit angiogenesis by activating the glucocorticoid receptor. Inhibition of the glucocorticoid-activating enzyme 11{beta}-hydroxysteroid dehydrogenase type 1 (11{beta}-HSD1) reduces tissue-specific glucocorticoid action and promotes angiogenesis in murine models of myocardial infarction. Angiogenesis is important in the growth of some solid tumours. This study used murine models of squamous cell carcinoma (SCC) and pancreatic ductal adenocarcinoma (PDAC) to test the hypothesis that 11{beta}-HSD1 inhibition promotes angiogenesis and subsequent tumour growth. SCC or PDAC cells were injected into female FVB/N or C57BL6/J mice fed either standard diet, or diet containing the 11{beta}-HSD1 inhibitor UE2316. SCC tumours grew more rapidly in UE2316-treated mice, reaching a larger (P<0.01) final volume (0.158 {+/-} 0.037 cm3) than in control mice (0.051 {+/-} 0.007 cm3). However, PDAC tumour growth was unaffected. Immunofluorescent analysis of SCC tumours did not show differences in vessel density (CD31/alpha-smooth muscle actin) or cell proliferation (Ki67) after 11{beta}-HSD1 inhibition, and immunohistochemistry of SCC tumours did not show changes in inflammatory cell (CD3- or F4/80-positive) infiltration. In culture, the growth/viability (assessed by live cell imaging) of SCC cells was not affected by UE2316 or corticosterone. Second Harmonic Generation microscopy showed that UE2316 reduced Type I collagen (P<0.001), whilst RNA-sequencing revealed that multiple factors involved in the innate immune/inflammatory response were reduced in UE2316-treated SCC tumours. 11{beta}-HSD1 inhibition increases SCC tumour growth, likely via suppression of inflammatory/immune cell signalling and extracellular matrix deposition, but does not promote tumour angiogenesis or growth of all solid tumours.

cancer biology↗

bioRxiv2021

Toll-like receptor 2 orchestrates a potent anti-tumor response in non-small cell lung cancer

Targeting early-stage lung cancer is vital to improve overall survival. We previously identified Toll-like receptor 2 (TLR2) as a regulator of oncogene-induced senescence (OIS) and the senescence-associated secretory phenotype (SASP), both key for tumor suppression. Here, we demonstrate that TLR2 is widely expressed in human lung tumor epithelium where it correlates with improved survival and clinical regression. Using genetically engineered mouse models of lung cancer we have shown that Tlr2 is a tumor suppressor in lung cancer initiation via regulation of proliferation and the SASP. The SASP is integral in the regulation of immune surveillance of premalignant cells, and we observe impaired myeloid derived immune surveillance following Tlr2 loss. Lastly, we show that administration of a synthetic Tlr2 agonist significantly reduces preinvasive lung tumor growth. Our data highlight an unexpected tumor surveillance pathway in early-stage lung cancer with therapeutic potential. Statement of significanceLung cancer is a major cancer of unmet need. This study identifies a novel tumor suppressor mechanism in lung cancer. Not only does this highlight a potential therapeutic target for early-stage disease but also multiple secreted candidate biomarkers that could be exploited to augment lung cancer screening approaches.

cancer biology↗

bioRxiv2020

Cytoplasmic innate immune sensing by the caspase-4 non-canonical inflammasome promotes cellular senescence.

Cytoplasmic recognition of microbially derived lipopolysaccharides (LPS) in human cells is elicited by the inflammatory cysteine aspartic proteases caspase-4 and caspase-5, which activate non-canonical inflammasomes inducing a form of inflammatory programmed cell death termed pyroptosis. Here we show that LPS mediated activation of the non-canonical inflammasome also induces cellular senescence and the activation of tumour suppressor stress responses in human diploid fibroblasts. Interestingly, this LPS-induced senescence is dependent on caspase-4, the pyroptotic effector protein gasdermin-D and the tumour suppressor protein p53. Also, experiments with a catalytically deficient mutant suggest that caspase-4 proteolytic activity is not necessary for its role in senescence. Furthermore, we found that the caspase-4 non-canonical inflammasome is induced and assembled during Ras-mediated oncogene-induced senescence (OIS). Moreover, targeting caspase-4 in OIS showed that the non-canonical inflammasome is critical for SASP activation and contributes to reinforcing the cell cycle arrest in OIS. Finally, we observed that caspase-4 induction occurs in vivo in models of tumour suppression and ageing. Altogether, we are unveiling that cellular senescence is induced by cytoplasmic microbial LPS recognition by the caspase-4 non-canonical inflammasome and that this pathway is conserved in the senescence program induced by oncogenic stress.

cell biology↗

bioRxiv2020

Loss of vacuolar acidity results in iron sulfur cluster defects and divergent homeostatic responses during aging in Saccharomyces cerevisiae

The loss of vacuolar/lysosomal acidity is an early event during aging that has been linked to mitochondrial dysfunction. However, it is unclear how loss of vacuolar acidity results in age-related dysfunction. Through unbiased genetic screens, we determined that increased iron uptake can suppress the mitochondrial respiratory deficiency phenotype of yeast vma mutants, which have lost vacuolar acidity due to genetic disruption of the vacuolar ATPase proton pump. Yeast vma mutants exhibited nuclear localization of Aft1, which turns on the iron regulon in response to iron sulfur cluster (ISC) deficiency. This led us to find that loss of vacuolar acidity with age in wildtype yeast causes ISC defects and a DNA damage response. Using microfluidics to investigate aging at the single cell level, we observe grossly divergent trajectories of iron homeostasis within an isogenic and environmentally homogeneous population. One subpopulation of cells fails to mount the expected compensatory iron regulon gene expression program, and suffers progressively severe ISC deficiency with little to no activation of the iron regulon. In contrast, other cells show robust iron regulon activity with limited ISC deficiency, which allows extended passage and survival through a period of genomic instability during aging. These divergent trajectories suggest that iron regulation and ISC homeostasis represent a possible target for aging interventions.

molecular biology↗

bioRxiv2019

ISGylation drives basal breast tumour progression by promoting EGFR recycling and Akt signalling

ISG15 is an ubiquitin-like modifier that is associated with reduced survival rates in breast cancer patients. However, the mechanism by which ISG15 achieves this remains elusive. We demonstrate that modification of Rab GDP-Dissociation Inhibitor Beta (GDI2) by ISG15 (ISGylation) alters endocytic recycling of the EGF receptor (EGFR). By regulating EGFR trafficking, ISGylation sustains Akt-signalling in vitro and in vivo. Persistent and enhanced Akt activation explains the more aggressive tumour behaviour observed in animal models and human breast cancers. We show that ISGylation can act as driver of tumour progression rather than merely being a marker of it.

cancer biology↗

bioRxiv2019

A Synergistic Anti-Cancer FAK and HDAC Inhibitor Combination Discovered by a Novel Chemical-Genetic High Content Phenotypic Screen

We mutated the Focal Adhesion Kinase (FAK) catalytic domain to inhibit binding of the chaperone, Cdc37 and ATP, mimicking the actions of a FAK kinase inhibitor. We re-expressed mutant and wild-type FAK in squamous cell carcinoma (SCC) cells from which endogenous FAK had been deleted, genetically fixing one axis of a FAK inhibitor combination high-content phenotypic screen to discover drugs that may synergize with FAK inhibitors. HDAC inhibitors represented the major class of compounds that potently induced multi-parametric phenotypic changes when FAK was rendered kinase-defective, or inhibited pharmacologically in SCC cells. Indeed, combined FAK and HDAC inhibitors arrest proliferation and induce apoptosis in a sub-set of cancer cell lines in vitro and efficiently inhibits tumor growth in vivo. Mechanistically, HDAC inhibitors potentiate inhibitor-induced FAK inactivation and reverses FAK-associated nuclear YAP in sensitive cancer cell lines. Here we report the discovery of a new clinically actionable synergistic combination between FAK and HDAC inhibitors.\n\nSignificanceWe describe a chemical-genetic, high-content phenotypic screening approach to discover effective anti-cancer combinations of targeted therapeutics through which we identified a novel, synergistic and clinically actionable, combination of FAK and HDAC inhibitors.

cancer biology↗

bioRxiv2018

The innate immune sensor Toll-like receptor 2 controls the senescence-associated secretory phenotype.

Cellular senescence is a stress response program characterised by a robust cell cycle arrest and the induction of a pro-inflammatory senescence-associated secretory phenotype (SASP) that is triggered through an unknown mechanism. Here, we show that during oncogene-induced senescence (OIS), the Toll-like receptor TLR2 and its partner TLR10 are key mediators of senescence in vitro and in murine models. TLR2 promotes cell cycle arrest by regulating the tumour suppressors p53-p21CIP1, p16INK4a and p15INK4b, and regulates the SASP through the induction of the acute-phase serum amyloids A1 and A2 (A-SAA) that, in turn, function as the damage associated molecular patterns (DAMPs) signalling through TLR2 in OIS. Finally, we found evidence that the cGAS-STING cytosolic DNA sensing pathway primes TLR2 and A-SAA expression in OIS. In summary, we report that innate immune sensing of senescence-associated DAMPs by TLR2 controls the SASP and reinforces the cell cycle arrest program in OIS.

cell biology↗