Biology subjects

O'Toole, S.

Publications and source records attributed to O'Toole, S..

12 recordsLinked to original sources

bioRxiv2026

Highly resolved tumor architecture via matched spatial and nucleus transcriptomics from a single tissue section

Spatial transcriptomics often relies on reference-based deconvolution to infer cell types in a tissue context; however, public single-cell datasets can miss patient-specific biology. Here we introduce SIMPlex, a method that generates matched spatial and single-nucleus gene-expression profiles from the same 5 um FFPE section. We demonstrate context-matched profiles across mouse brain, breast cancer and prostate cancer tissues, resolving fine-grained cell-states with distinct spatial signatures. By extracting both spatial and nuclear layers, SIMPlex maximises the information recovered from a single tissue section, an advantage for scarce archival and clinical specimens.

molecular biology↗

bioRxiv2025

ROCK2 inhibition has a dual role in reducing ECM remodelling and cell growth, while impairing migration and invasion

The Rho-associated coiled-coil containing protein kinases 1/2 (ROCK1/2) are key signalling proteins involved in the regulation of the actin cytoskeleton and control a variety of cellular processes. This includes cell proliferation, stemness, cell migration and invasion as well as actomyosin contraction and extracellular matrix (ECM) remodelling. Due to a lack of ROCK2 specific inhibitors, previous pharmacological studies of ROCK function have relied on pan-ROCK1/2 inhibition. Here, we use the ROCK2 specific inhibitor, GV101, in the context of breast cancer (BC) models to uncouple the effects of ROCK2 pharmacological inhibition on both epithelial and stromal fibroblast cell populations. We demonstrate that ROCK2 inhibition with GV101 reduces fibroblast-mediated remodelling of pre-existing and de novo synthesised ECM resulting in a reduction in biomechanical stiffness, while also limiting epithelial cell growth in 2D and 3D settings. We also demonstrate that ROCK2 inhibition exposes epithelial cell vulnerability to fluid flow-induced shear stress. Furthermore, using 3D co-cultures we reveal that GV101 reduces single-cell migratory capacity, while the disruption of stromal ECM architecture is sufficient to impede collective cell migration and invasion. Finally, we assessed ROCK2 expression in human BC patient tumours revealing that ROCK2 expression is up-regulated during BC progression and that high ROCK2 expression correlates with poor patient outcome in the triple-negative subtype of BC. Together, these results demonstrate that ROCK2 specific inhibition disrupts key functions in both epithelial cell and stromal fibroblast compartments warranting further assessment of ROCK2 in highly proliferative, fibrotic or metastatic diseases, such as BC. HighlightsO_LIFibroblast-mediated remodelling of pre-existing and de novo synthesised extracellular matrix is reduced upon ROCK2 specific targeting. C_LIO_LIROCK2 inhibition impairs epithelial cancer cell growth and colony formation in 2D and 3D contexts, while also limiting single-cell migration and cell survival upon fluid flow-induced shear stress. C_LIO_LIROCK2 targeting during fibroblast-mediated ECM remodelling is sufficient to disrupt collective cell migration as well as 3D invasion into organotypic fibroblast-contracted collagen matrices. C_LIO_LIROCK2 expression is up-regulated during breast cancer progression and high expression correlates with poor patient outcome in triple-negative breast cancer. C_LI

cell biology↗

bioRxiv2025

A selective inhibitor of oncogenic JNK signalling perturbs metastatic outgrowth of triple-negative breast cancer through metabolic blockade

Although c-Jun N-terminal Kinase (JNK) represents an attractive anti-cancer target, its pleiotropic functionality limits the use of direct JNK inhibitors. Here, we identify a distinct subcellular pattern of JNK activity as a therapeutic vulnerability in breast cancer, where cytoplasmic JNK activity predicts poor survival outcomes, is elevated in triple-negative breast cancers (TNBC) and is essential for metastatic outgrowth. Mechanistic analyses reveal cytoplasmic JNK acts through multiple mechanisms, with downstream targets involved in cellular metabolism and cytoskeletal regulation. On this basis, we leveraged actin-based phenotypic drug-screening and identified K12, an indirect but selective inhibitor of cytoplasmic JNK that blocks TNBC metastatic outgrowth in vivo. We reveal that K12 inhibits glutaminase-1 and the pyruvate dehydrogenase complex, and that this poly-pharmacology overcomes pyruvate anaplerosis, a known resistance mechanism of existing glutaminase inhibitors. These findings demonstrate the potential of selectively targeting the oncogenic function of JNK, offering new treatment options for early-stage metastatic TNBC.

cancer biology↗

bioRxiv2024

Design, Synthesis, and Efficacy of Novel Trojan Horse Compounds Targeting Metabolic Vulnerabilities in Prostate Cancer

Background and purposeProstate cancer (PCa) remains a significant global health concern, warranting the development of new therapeutic strategies.1 Metabolic reprogramming, an emerging hallmark of PCa progression characterized by aberrant nutrient utilization, has become a focus area in developing new treatments. Among these metabolic alterations, the Warburg effect--a shift towards aerobic glycolysis-- has garnered significant attention as a potential therapeutic target. 2 To explore this, we synthesised a novel class of Trojan Horse compounds designed to exploit the unique metabolic profile of cancer cells and investigated their therapeutic potential using cell based models of PCa, as a proof of principle strategy. Experimental approachPreliminary cytotoxicity analysis revealed that native menadione had low efficacy against PCa cells. Consequently, we developed glucose and fatty acid conjugated TH compounds based on a menadione backbone. A library of six novel menadione-glucose and fatty acid-based TH compounds were synthesized through copper-catalysed click chemistry. These compounds were designed to mimic a desirable fuel source (sugar or fatty acid) acting as a "Trojan Horse" for PCa cells to modulate their metabolism. The cytotoxic and selective effects of the TH compounds were evaluated in PCa and non-malignant cell lines cultured under varying glucose conditions. To elucidate the mechanisms of action, mitochondrial bioenergetics, metabolic phenotyping, and metabolomic profiling were employed to assess the impact of each TH compound on cellular metabolism. Key resultsTH3 (glucose) and TH5 (fatty acid) compounds demonstrated promising cytotoxicity for PCa cell lines, with TH5 exhibiting superior selectivity compared to TH3 and particularly over native menadione. Despite these results, alterations in metabolic phenotypes were only modest. Mitochondrial bioenergetics were notably impacted by TH5, while ROS levels remained stable post-treatment, likely due to an increase in ROS scavenging amino acids as a compensatory antioxidant response. Conclusion and ImplicationsThis study demonstrates the potential of employing glucose and fatty acid-conjugated compounds to target the unique metabolic features of PCa. These findings offer promising new avenues for further investigation, aimed at optimizing efficacy and selectivity of these compounds for clinical translation. The intricate relationship between ROS production and antioxidant defence mechanisms emphasizes the complex nature of metabolic interventions in cancer. Elucidating the mode of action and exploring molecular modifications may pave the way for personalised and targeted PCa therapies, ultimately improving patient outcomes and mitigating the global burden of this disease. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/610353v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1af7915org.highwire.dtl.DTLVardef@1368f16org.highwire.dtl.DTLVardef@ebfe63org.highwire.dtl.DTLVardef@18a181b_HPS_FORMAT_FIGEXP M_FIG C_FIG Significance statementThis body of work gives critical insights into the metabolic vulnerabilities of prostate cancer (PCa), particularly of androgen-independent and metastatic disease, which currently present significant treatment challenges. By designing, synthesising and testing innovative menadione-based Trojan Horse compounds that target altered cancer cell metabolism, this research highlights a promising new therapeutic strategy against malignant cells. The findings underscore the potential for metabolic reprogramming to combat treatment resistance in advanced PCa, paving the way forward for the development of new drugs and personalised treatment approaches. This could lead to improved outcomes for patients with currently untreatable forms of the disease.

cancer biology↗

bioRxiv2024

Macropinocytosis mediates resistance to loss of glutamine transport in triple-negative breast cancer

Triple-negative breast cancer (TNBC) relies on glutamine uptake by the transporter ASCT2 to sustain their unique glutamine metabolism and growth. Despite previous data showing cell growth inhibition after ASCT2 knockdown, ASCT2 CRISPR knockout was well-tolerated by breast cancer cell lines. Despite the loss of a glutamine transporter and low rate of glutamine uptake, intracellular glutamine steady state levels were higher in ASCT2 knockout compared to control TNBC cells. Proteomics data revealed upregulation of macropinocytosis, reduction in glutamine efflux and glutamine synthesis in ASCT2 knockout cells. Loss of ASCT2 in TNBC cell line HCC1806 induced a 5-10-fold increase in macropinocytosis across 5 separate ASCT2 knockout clones, compared to a modest 2-fold increase in the shRNA ASCT2 knockdown. By comparison, ASCT2 knockout impaired cell proliferation in a non-macropinocytic breast cancer cell line, HCC1569. These data suggest that macropinocytosis provides a novel resistance mechanism to strategies targeting glutamine uptake alone. Despite this adaptation, TNBC cells continue to rely on glutamine metabolism for their growth, which suggests therapeutic targeting may need to focus on downstream glutamine metabolism pathways.

cancer biology↗

bioRxiv2024

A comparative study of circulating tumor cell isolation and enumeration technologies in lung cancer

Circulating tumor cells (CTCs) have potential as diagnostic, prognostic and predictive biomarkers in solid tumors. Despite FDA approval of CTC devices in various cancers, their rarity and limited comparison between analysis methods hinder their clinical integration for lung cancer. This study aimed to evaluate five CTC isolation technologies using a standardized spike-in protocol: the CellMag (EpCAM-based enrichment), EasySep and RosetteSep (blood cell depletion), and the Parsortix(R) PR1 and next generation Parsortix(R) Plus (PX+) (size-based enrichment). The Parsortix(R) systems were also evaluated for any difference in recovery rates between cell harvest versus in- cassette staining. Healthy donor blood (5 mL) was spiked with 100 fluorescently labeled H1975 lung adenocarcinoma cell line, processed through each system and the isolation efficiency was calculated. All tested systems yielded discordant recovery rates with the CellMag having the highest mean recovery (70 {+/-} 14%) followed by the PR1 (in-cassette staining) with a recovery of 49 {+/-} 2% while the EasySep had the lowest recovery (18 {+/-} 8%). The CellMag and Parsortix(R) PR1 may have potential clinical applications for lung cancer patients, albeit needing further optimization and validation.

cancer biology↗

bioRxiv2023

snPATHO-seq: unlocking the pathology archives

Formalin-fixed paraffin-embedded (FFPE) samples are valuable but underutilized in single-cell omics research due to their low DNA and RNA quality. In this study, leveraging recent single-cell genomic technology advances, we introduce a versatile method to derive high-quality single-nucleus transcriptomic data from FFPE samples.

molecular biology↗

bioRxiv2023

An experimental comparison of the Digital Spatial Profiling and Visium spatial transcriptomics technologies for cancer research

BackgroundSpatial transcriptomic technologies are powerful tools for resolving the spatial heterogeneity of gene expression in tissue samples. However, little evidence exists on relative strengths and weaknesses of the various available technologies for profiling human tumour tissue. In this study, we aimed to provide an objective assessment of two common spatial transcriptomics platforms, 10X Genomics Visium and Nanostrings GeoMx DSP. MethodThe abilities of the DSP and Visium platforms to profile transcriptomic features were compared using matching cell line and primary breast cancer tissue samples. A head-to-head comparison was conducted using data generated from matching samples and synthetic tissue references. Platform specific features were also assessed according to manufacturers recommendations to evaluate the optimal usage of the two technologies. ResultsWe identified substantial variations in assay design between the DSP and Visium assays such as transcriptomic coverage and composition of the transcripts detected. When the data was standardised according to manufacturers recommendations, the DSP platform was more sensitive in gene expression detection. However, its specificity was diminished by the presence of non-specific detection. Our results also confirmed the strength and weakness of each platform in characterising spatial transcriptomic features of tissue samples, in particular their application to hypothesis generation versus hypothesis testing. ConclusionIn this study, we share our experience on both DSP and Visium technologies as end users. We hope this can guide future users to choose the most suitable platform for their research. In addition, this dataset can be used as an important resource for the development of new analysis tools.

cancer biology↗

bioRxiv2020

Cryopreservation of human cancers conserves tumour heterogeneity for single-cell multi-omics analysis

BackgroundHigh throughput single-cell RNA sequencing (scRNA-Seq) has emerged as a powerful tool for exploring cellular heterogeneity amongst complex human cancers. scRNA-Seq studies using fresh human surgical tissue is logistically difficult, precludes histopathological triage of samples and limits the ability to perform batch processing. This hinderance can often introduce technical biases when integrating patient datasets and increase experimental costs. Although tissue preservation methods have been previously explored to address such issues, it is yet to be examined on complex human tissues, such as solid cancers, and on high throughput scRNA-Seq platforms. ResultsWe show that the viable cryopreservation of human cancers provides high quality single-cell transcriptomes using the Chromium 10X platform. We sequenced a total of [~]120,000 cells from fresh and cryopreserved replicates across three breast cancers, two prostate cancers and a cutaneous melanoma. Importantly, tumour heterogeneity identified from fresh tissues was largely conserved in cryopreserved replicates. We show that sequencing of single cells prepared from cryopreserved tissue fragments or from cryopreserved cell suspensions is comparable to sequenced cells prepared from fresh tissue, with cryopreserved cell suspensions displaying higher correlations with fresh tissue in gene expression. We then show that cryopreservation had minimal impacts on results of downstream analyses such as biological pathway enrichment. Further, we demonstrate the advantage of cryopreserving whole-cells for immunophenotyping methods such as CITE-Seq, which is impossible using other preservation methods such as single nuclei-sequencing. ConclusionsOur study guides new experimental designs for tissue biobanking for future clinical single-cell RNA sequencing studies.

cancer biology↗

bioRxiv2020

Single-cell analysis reveals diverse stromal subsets associated with immune evasion in triple-negative breast cancer

The tumour stroma regulates nearly all stages of carcinogenesis. Stromal heterogeneity in human triple-negative breast cancers (TNBCs) remains poorly understood, limiting the development of stromal-targeted therapies. Single cell RNA-sequencing of five TNBCs revealed two cancer-associated fibroblast (CAF) and two perivascular-like (PVL) subpopulations. CAFs clustered into two states, the first with features of myofibroblasts and the second characterised by high expression of growth factors and immunomodulatory molecules. PVL cells clustered into two states consistent with a differentiated and immature phenotype. We showed that these stromal states have distinct morphologies, spatial relationships and functional properties in regulating the extracellular matrix. Using cell-signalling predictions, we provide evidence that stromal-immune crosstalk acts via a diverse array of immunoregulatory molecules. Importantly, the investigation of gene signatures from inflammatory-CAFs and differentiated-PVL cells in independent TNBC patient cohorts revealed strong associations with cytotoxic T-cell dysfunction and exclusion, respectively. Such insights present promising candidates to further investigate for new therapeutic strategies in the treatment of TNBCs.

cancer biology↗

bioRxiv2018

A novel role for the HLH protein Inhibitor of Differentiation 4 (ID4) in the DNA damage response in basal-like breast cancer.

Basal-like breast cancer (BLBC) is a poorly characterised, heterogeneous disease. Patients are diagnosed with aggressive, high-grade tumours and often relapse with chemotherapy resistance. Detailed understanding of the molecular underpinnings of this disease is essential to the development of personalised therapeutic strategies. Inhibitor of Differentiation 4 (ID4) is a helix-loop-helix transcriptional regulator required for mammary gland development. ID4 is overexpressed in a subset of BLBC patients, associating with a stem-like poor prognosis phenotype, and is necessary for the growth of cell line models of BLBC, through unknown mechanisms. Here, we have defined a molecular mechanism of action for ID4 in BLBC and the related disease highgrade serous ovarian cancer (HGSOV), by combining RIME proteomic analysis and ChIP-Seq mapping of genomic binding sites. Remarkably, these studies have revealed novel interactions with DNA damage response proteins, in particular, mediator of DNA damage checkpoint protein 1 (MDC1). Through MDC1, ID4 interacts with other DNA repair proteins ({gamma}H2AX and BRCA1) at fragile chromatin sites. ID4 does not affect transcription at these sites, instead binding to chromatin following DNA damage and regulating DNA damage signalling. Clinical analysis demonstrates that ID4 is amplified and overexpressed at a higher frequency in BRCA1-mutant BLBC compared with sporadic BLBC, providing genetic evidence for an interaction between ID4 and DNA damage repair pathways. These data link the interactions of ID4 with MDC1 to DNA damage repair in the aetiology of BLBC and HGSOV.

cancer biology↗

bioRxiv2017

Targeting stromal remodeling and cancer stem cell plasticity to overcome chemoresistance in triple negative breast cancer

The cellular and molecular basis of stromal cell recruitment, activation and crosstalk in carcinomas is poorly understood, limiting the development of targeted anti-stromal therapies. In mouse models of triple negative breast cancer (TNBC), Hh ligand produced by neoplastic cells reprogrammed cancer-associated fibroblast (CAF) gene expression, driving tumor growth and metastasis. Hh-activated CAFs upregulated expression of FGF5 and production of fibrillar collagen, leading to FGFR and FAK activation in adjacent neoplastic cells, which then acquired a stem-like, drug-resistant phenotype. Treatment with smoothened inhibitors (SMOi) reversed these phenotypes. Stromal treatment of TNBC patient-derived xenograft (PDX) models with SMOi downregulated the expression of cancer stem cell markers and sensitized tumors to docetaxel, leading to markedly improved survival and reduced metastatic burden. In the phase I clinical trial EDALINE, 3 of 12 patients with metastatic TNBC derived clinical benefit from combination therapy with the SMOi Sonidegib and docetaxel chemotherapy, with one patient experiencing a complete response. Markers of pathway activity correlated with response. These studies identify Hh signaling to CAFs as a novel mediator of cancer stem cell plasticity and an exciting new therapeutic target in TNBC.\n\nSIGNIFICANCECompared to other breast cancer subtypes, TNBCs are associated with significantly worse patient outcomes. Standard of care systemic treatment for patients with non-BRCA1/2 positive TNBC is cytotoxic chemotherapy. However, the failure of 70% of treated TNBCs to attain complete pathological response reflects the relative chemoresistance of these tumors. New therapeutic strategies are needed to improve patient survival and quality of life. Here, we provide new insights into the dynamic interactions between heterotypic cells within a tumor. Specifically, we establish the mechanisms by which CAFs define cancer cell phenotype and demonstrate that the bidirectional CAF-cancer cell crosstalk can be successfully targeted in mice and humans using anti-stromal therapy.

cancer biology↗