Biology subjects

Brunton, V. G.

Publications and source records attributed to Brunton, V. G..

5 recordsLinked to original sources

bioRxiv2021

Characterisation of a nucleo-adhesome

In addition to central functions in cell adhesion signalling, integrin-associated proteins have wider roles at sites distal to adhesion receptors. In experimentally defined adhesomes, we noticed that there is clear enrichment of proteins that localise to the nucleus, and conversely, we now report that nuclear proteomes contain a class of adhesome components that localise to the nucleus. We here defined a nucleo-adhesome, providing experimental evidence for a remarkable scale of nuclear localisation of adhesion proteins, establishing a framework for interrogating nuclear adhesion protein functions. In adding to nuclear FAKs known roles in regulating transcription, we now show that nuclear FAK regulates expression of many adhesion-related proteins that localise to the nucleus and that nuclear FAK binds to the adhesome component and nuclear protein Hic-5. FAK and Hic-C work together in the nucleus, co-regulating a subset of genes transcriptionally. We describe the first nucleo-adhesome using a squamous cancer cell model, and demonstrate the new principle that there are nuclear adhesion protein subcomplexes that cooperate to control transcription. O_FIG O_LINKSMALLFIG WIDTH=177 HEIGHT=200 SRC="FIGDIR/small/458428v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@1c841ceorg.highwire.dtl.DTLVardef@586a75org.highwire.dtl.DTLVardef@b54439org.highwire.dtl.DTLVardef@921537_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell 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↗

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

Identification of stromal genes differentially expressed in lobular breast cancer highlights role for pregnancy-associated-plasma protein-A

BackgroundInvasive lobular carcinoma (ILC) is the second most common histological subtype of breast cancer and exhibits a number of clinico-pathological characteristics that are distinct from the more common invasive ductal carcinoma (IDC). Despite these differences, ILC is treated in the same way as IDC. We set out to identify alterations in the tumor microenvironment (TME) of ILC with potential clinical significance. MethodsWe used laser-capture microdissection (LCM) to separate tumor epithelium from stroma in 23 ER+ ILC samples. Gene expression analysis was used to identify genes that are enriched in the stroma of ILC, but not IDC or normal breast. Results45 genes involved in regulation of the extracellular matrix (ECM) were enriched in the stroma of ILC, but not stroma from ER+ IDC or normal breast. Of these, 10 were expressed in cancer-associated fibroblasts (CAFs) and were increased in ILC compared to IDC in bulk gene expression datasets. PAPPA was the most enriched in the stroma compared to the tumor epithelial compartment in ILC. PAPPA encodes pregnancy-associated plasma protein-A (PAPP-A), a metalloproteinase that cleaves insulin-like binding protein-4 (IGFBP-4) increasing IGF-1 bioavailability and subsequent downstream signaling. Analysis of PAPPA and IGF1 associated genes identified a paracrine signaling pathway and active PAPP-A was shown to be secreted from primary CAFs. Comprehensive survival analysis across 3000 breast cancers identified PAPPA as a potential ILC-specific prognostic marker. ConclusionsThis is the first study to demonstrate molecular differences in the TME between ILC and IDC and identifies PAPP-A, a CAF-derived proteinase, as a potential prognostic marker.

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↗