Biology subjects

O'Brien, B.

Publications and source records attributed to O'Brien, B..

10 recordsLinked to original sources

bioRxiv2026

Serial Thermal Ablation Induces Abscopal Antitumor Immunity and Reveals Targetable CSF1R-Dependent Resistance in Pancreatic Cancer

Thermal ablation is increasingly used for local control of pancreatic ductal adenocarcinoma (PDAC), but its capacity to induce systemic antitumor immunity and the mechanisms limiting this response remain incompletely defined. Using a bilateral LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) flank tumor model, we show serial radiofrequency ablation (RFA) enhances local tumor control and induces a robust abscopal response. This effect was associated with increased activation of CD8 T cells and natural killer cells, and was abrogated by CD8 T cell depletion. Single-cell RNA sequencing revealed expansion of cytotoxic immune programs alongside induction of a CSF1R-driven myeloid response consistent with adaptive immune resistance. Although combinatorial blockade of PD-L1 and CD73 augmented systemic antitumor responses, and the addition of CSF1R inhibition in this context further enhanced both local and distant tumor control. These findings identify a CSF1R-dependent myeloid resistance program which constrains ablation-induced systemic immunity and demonstrate that rational combination immunotherapy can potentiate the systemic efficacy of tumor ablation in PDAC. STATEMENT OF TRANSLATIONAL RELEVANCERadiofrequency ablation is a local thermal therapy that induces tumor destruction and modulation of the tumor microenvironment used for treatment of many solid tumors, including pancreatic cancer. Serial thermal ablations induce a CD8+ T cells and NK cell antitumor immunological response; however, Nt5e (CD73) is increased in tumor cells, PD-1 is increased in CD8+ T cells, and serial ablations increase a CSF1R+ macrophage cluster in ablated tumors. Combinational targeting of CD73, PD-L1, and CSF1R alleviates CSF1R-dependent therapeutic resistance and enhances local and systemic tumor control. This study identifies targetable countervailing mechanisms to local ablation therapy and provides a rationale for combinatorial strategies integrating serial tumor ablation with systemic immunomodulatory agents. Future prospective studies should evaluate the influence of timing, dosage, and sequence of ablation on immune priming to improve clinical interventions in pancreatic cancer.

cancer biology↗

bioRxiv2025

Dietary Fat Content Influences PanIN Progression and Pancreatic Cancer Development in Mice

Dietary macronutrient composition has emerged as a key modulator of pancreatic tumorigenesis, yet the impact of lipid-rich diets, particularly ketogenic diets (KD) on the earliest stages of pancreatic cancer development remains unclear. To investigate how dietary lipids shape the initiation and progression of Kras-driven neoplasia, we examined the effects of low-fat diet (LFD), high-fat diet (HFD), and KD in the Ptf1aCreERT2;KrasG12V (AcinarKrasG12V) mouse model. KD-fed mice showed the shortest survival (median 26 {+/-} 7 days) compared with SD (87 {+/-} 29; p = 0.02) and LFD (57 {+/-} 27; p = 0.02), while HFD-fed mice also exhibited reduced survival relative to SD (35 {+/-} 25; p = 0.05). KD feeding induced severe glucose intolerance and elevated circulating {beta}-hydroxybutyrate levels. Histologically, KD-fed AcinarKrasG12V mice developed invasive, sarcomatoid-like pancreatic ductal adenocarcinoma (PDAC), while HFD-fed mice showed increased poorly differentiated PDAC; in both groups these aggressive tumors were associated with extensive fibrosis and increased stromal CD39 expression relative to tumor compartments. Proteomic analysis demonstrated activation of PI3K-Akt-mTOR and EGFR signaling in KD and HFD-fed AcinarKrasG12V mice. Serum cytokines/chemokines profiling revealed pro-inflammatory and pro-angiogenic milieu in KD-fed AcinarKrasG12Vmice. Collectively, these results show that dietary lipid enrichment prior to oncogenic Kras activation may accelerate early pancreatic neoplasia and foster a microenvironment conducive to tumor progression. These findings underscore the need for careful consideration of KD use in individuals at elevated risk for pancreatic cancer.

cancer biology↗

bioRxiv2025

Integrating 12 Spatial and Single Cell Technologies to Characterise Tumour Neighbourhoods and Cellular Interactions in three Skin Cancer Types

Cutaneous squamous cell carcinoma (cSCC), basal cell carcinoma (BCC), and melanoma - the three major skin cancers - collectively comprise over 70% of all cancer cases. Despite their prevalence, much understanding of cellular interactions in the skin cancer microenvironment is needed, both in the outer skin layer where the cancer originates and at the deeper junctional and dermal layers into which it progresses. To address this gap, we integrated 12 complementary spatial and single-cell technologies to generate orthogonally-validated cell signatures, spatial maps, and interactomes for cSCC, BCC, and melanoma. Through comprehensive comparisons and integrating these spatial methods, we provided practical benchmarking guidelines for experimental design and analysis. By identifying keratinocyte cancer cells and melanomas, we found distinct signatures of these cells compared to non-cancer keratinocytes and melanocytes. Spatial integration of transcriptomics, proteomics and glycomics uncovered cancer niches enriched for cancer initiating cells (melanocytes or keratinocytes) and fibroblast and T-cell (MKFT) clusters, with altered tyrosine and pyrimidine metabolism. Ligand-receptor analysis across >700 cell-type combinations and >1.5 million interactions highlighted key roles for CD44, integrins, and collagens, with CD44-FGF2 emerging as a potential therapeutic target. Consistently, melanoma showed strong MFT interactions, validated by Opal Polaris, RNAScope, Proximal Ligation Assay and two additional single-cell spatial platforms (making a total of 14 technologies). For population-scale generalisation, genetic associations from >500,000 individuals were mapped onto spatial skin tissues, identifying SNPs enriched in domains containing melanocytes and T cells and their ligand-receptor pairs, shedding light on functional mechanisms linking genetic heritability to cells within cancer tissue. We built an interactive multiomics resource for exploring spatially-resolved molecular signatures and cellular crosstalk in skin cancer, available at https://skincanceratlas.com.

cancer biology↗

bioRxiv2025

Canonical nuclear envelope protein emerin regulates structure and integrity of the erythrocyte plasma membrane

Red blood cells (RBC) are essential for the survival of aerobic organisms. Mutations in RBC plasma membrane proteins can give rise to a spectrum of diseases characterized by hemolysis, inefficient gas exchange, and anemia. We tested whether emerin (EMD), a nuclear envelope (NE) protein, is also expressed in anuclear cell types to regulate membrane structure and function. We find that emerin is localized to the RBC plasma membrane and regulates the localization of other membrane proteins involved in actin branching and cytoskeletal dynamics. Additionally, we find that loss of Emd in mice results in decreased RBC corpuscular volume and hemoglobin content in both sexes, as well as a male-specific increase in RBC number and hematocrit, consistent with other male-dominated EMD phenotypes. Along with decreased RBC size, we observed a reduction in the rate of osmotic lysis in Emd KO animals, particularly males. We found that human EMD mutations also have a statistically significant association with RBC phenotypes, namely MCV. Individuals with emerin-related Emery-Dreifuss muscular dystrophy (EDMD) also demonstrate a mild yet consistent RBC phenotype according to patient CBC data. Together, these data suggest that emerin can have cell-specific localization and functions independent of its canonical repertoire in nucleated cells.

cell biology↗

bioRxiv2024

The Composition of the Bacterial Community in Raw Milk from Holstein Dairy Cattle Correlated with the Occurrence of Klebsiella pneumoniae Clinical Mastitis Infections

Klebsiella pneumoniae is a common, opportunistic bacterial pathogen that can cause severe clinical mastitis in dairy cattle. Optimizing the bovine udder microbiome to resist mastitis pathogens is a growing area of research; however, previous work has not examined which members of the mammary microbiome may have antagonistic interactions with K. pneumoniae. In this study, we collected quarter-level milk samples from Holstein dairy cows in Quebec, Canada every two weeks for 14 months and analyzed differences in the milk microbiome between samples that were collected from healthy quarters, quarters that developed subclinical mastitis, and quarters that experienced K. pneumoniae clinical mastitis (KP-CM) (n = 512 milk samples). The occurrence of subclinical mastitis did not cause significant differences in the alpha-diversity of the milk microbiome, nor did subclinical mastitis alter the interactions between taxa in the microbiome. However, the occurrence of KP-CM caused reductions in Shannon diversity in raw milk relative to healthy milk and altered the interactions between taxa. Specifically, K. pneumoniae showed negative interactions with the genus Aerococcus. The negative interactions between Aerococcus spp. and K. pneumoniae in the context of the bovine milk microbiome should be analyzed further.

microbiology↗

bioRxiv2023

Biocompatible hydrogel electrodeposition enables the simultaneous preparation of multi-microinterfaces for ligand bioconjugation and multiplexed electrochemical detection

Affinity based electrochemical biosensing systems with integrated miniaturised interfaces has enabled key advancement toward rapid, sensitive, precise and deployable detection platforms. Manufacturing silicon micro/nano devices for biology interface has been a highly promising platform to design and develop electrochemical sensors for the detection of very low concentrations of the target molecules. However, the biofouling challenge of the biosensors when the surface is exposed to a complex matrix such as blood, serum, milk, has been a road blocker. Here we introduce a simple, rapid formation of an anti-biofouling coating onto several electroactive surface areas present on a single chip simultaneously. Using such a multiplexed surface, we were able to investigate the optimum working conditions on-chip. Concentrating on two individual bioassay platforms for stress biomarkers, haptoglobin and cortisol, we demonstrate the broad applicability of the developed universal platform with excellent performance in bovine serum and correlation with conventional ELISA using milk samples.

bioengineering↗

bioRxiv2022

Radiofrequency ablation remodels the tumor microenvironment and promotes systemic immunomodulation in pancreatic cancer

Background and AimsPancreatic ductal adenocarcinoma (PDAC) is characterized by resistance to therapy. A major contributing factor to therapeutic failure is profound desmoplasia and a well-documented hypoxic tumor microenvironment (TME). In PDAC, several therapeutic approaches, including chemotherapy and radiation alone or combined with immune checkpoint inhibitors, have shown minimal therapeutic success, placing an imperative need for the discovery and application of innovative treatments. Endoscopic ultrasound guided radiofrequency ablation (EUS-RFA) is a promising immunomodulator therapy for PDAC. In this work, we hypothesized RFA promotes local and systemic stromal and immunomodulating effects that can be identified for new combination therapeutic strategies. MethodsTo test our hypothesis, a syngeneic PDAC mouse model was performed by symmetrically injecting 100k murine KPC cells in bilateral flanks of C57BL/6 female mice. RFA treatment initiated when tumors reached 200-500 mm3 and was performed only in the right flank. The left flank tumor (non-RFA contralateral side) was used as a paired control for further analysis. ResultsRFA promoted a significant reduction in tumor growth rate 4 days after treatment in RFA treated and non-RFA side contralateral tumors from treated mice when compared to controls. Histological analysis revealed a significant increase in expression of cleaved Caspase3 in RFA treated tumors. In addition, collagen deposition and CD31+ cells were significantly elevated in RFA side and non-RFA contralateral tumors from RFA treated mice. Proteome profiling showed changes in C5a and IL-23 in RFA responsive tumors, indicating a role of RFA in modulating intratumoral inflammatory responses. ConclusionsThese data indicate RFA promotes local and systemic anti-tumor responses in a syngeneic mouse model of PDAC implicating RFA treatment for local tumors as well as metastatic disease. Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

cancer biology↗

bioRxiv2020

Pan-resistant Candida auris: New York Sub-cluster Susceptible to Antifungal Combinations

Four pan-resistant Candia auris strains from New York outbreak were 100% inhibited in vitro by combinations of two antifungal drugs using fixed concentrations achievable in vivo. Pan-resistant C. auris strains have mutations in eleven gene targets associated with major antifungal drugs, and constituted a distinct sub-cluster among NY strains.

microbiology↗

bioRxiv2019

Laboratory Analysis of an Outbreak of Candida auris in New York from 2016 to 2018-Impact and Lessons Learned

Candida auris is a multidrug-resistant yeast which has emerged in healthcare facilities worldwide, however little is known about identification methods, patient colonization, spread, environmental survival, and drug resistance. Colonization on both biotic and abiotic surfaces, along with travel, appear to be the major factors for the spread of this pathogen across the globe. In this investigation, we present laboratory findings from an ongoing C. auris outbreak in NY from August 2016 through 2018. A total of 540 clinical isolates, 11,035 patient surveillance specimens, and 3,672 environmental surveillance samples were analyzed. Laboratory methods included matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for yeast isolate identification, real-time PCR for rapid surveillance sample screening, culture on selective/non-selective media for recovery of C. auris and other yeasts from surveillance samples, antifungal susceptibility testing to determine the C. auris resistance profile, and Sanger sequencing of ribosomal genes for C. auris genotyping. Results included: a) identification and confirmation of C. auris in 413 clinical isolates and 931 patient surveillance isolates, as well as identification of 277 clinical cases and 350 colonized cases from 151 healthcare facilities including 59 hospitals, 92 nursing homes, 1 long-term acute care hospital (LTACH), and 2 hospices, b) successful utilization of an in-house developed C. auris real-time PCR assay for the rapid screening of patient and environmental surveillance samples, c) demonstration of relatively heavier colonization of C. auris in nares compared to the axilla/groin, and d) predominance of the South Asia Clade I with intrinsic resistance to fluconazole and elevated minimum inhibitory concentration (MIC) to voriconazole (81%), amphotericin B (61%), 5-FC (3%) and echinocandins (1%). These findings reflect greater regional prevalence and incidence of C. auris and the deployment of better detection tools in an unprecedented outbreak.

microbiology↗

bioRxiv2019

Efficacy of antifungal drug combinations against widespread primary resistance, cross-resistance, and multidrug-resistance in Candida auris from New York Hospitals and Healthcare Facilities

Since 2016, New York hospitals and healthcare facilities have faced an unprecedented outbreak of pathogenic yeast Candida auris. We tested over one thousand C. auris isolates from affected facilities and found high-resistance to fluconazole (FLC, MIC50>256 mg/L), and variable resistance to other antifungal drugs. Therefore, we evaluated if two-drug combinations are effective in vitro against multidrug-resistant C. auris. Broth micro-dilution (BMD) plates were custom-designed, and quality controlled by TREK Diagnostic System. We used MIC100 endpoints for the drug combination readings as reported earlier for the intra- and inter-laboratory agreements against Candida species and Aspergillus fumigatus. The study results were derived from 12,960 MIC100 readings, for fifteen C. auris isolates tested against 864 possible two-drug antifungal combinations for nine antifungal drugs. Flucytosine (5FC) at 1.0 mg/L potentiated the most successful combinations with other drugs. Micafungin (MFG), Anidulafungin (AFG), Caspofungin (CAS) at individual concentrations of 0.25 mg/L in combination with 5FC (1.0 mg/L) yielded MIC100 for 14, 13, and 12 of 15 C. auris test isolates. AMB / 5FC (0.25/1.0 mg/L) yielded MIC100 for 13 isolates. None of the combinations were effective for C. auris 18-1, which tested resistant against FLC and 5FC, except POS/5FC (0.12/1.0 mg/L). The simplified two-drug combination susceptibility test format would permit laboratories to provide clinicians and public health experts with additional data to deal with multidrug-resistant C. auris.

microbiology↗