Publications by authors named "Martin Stuart"

Circulating tumor cells (CTCs) travel through the vasculature to seed secondary sites and serve as direct precursors of metastatic outgrowth for many solid tumors. Heterotypic cell clusters form between CTCs and white blood cells (WBCs) and recent studies report that a majority of these WBCs are neutrophils in patient and mouse models. The lab discovered that CTCs produce tubulin-based protrusions, microtentacles (McTNs), which promote reattachment, retention in distant sites during metastasis and formation of tumor cell clusters.

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We present the use of stimulated Brillouin scattering spectroscopy to achieve rapid measurements of cell biomechanics in a flow cytometer setup. Specifically, our stimulated Brillouin scattering flow cytometry can acquire at a rate of 200 Hz, with a spectral acquisition time of 5 ms, which marks a 10x improvement compared to previous demonstrations of spontaneous Brillouin scattering flow cytometry. We experimentally validate our stimulated Brillouin scattering flow cytometer by measuring cell populations of normal breast epithelial cells and metastatic breast epithelial cancer cells.

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Cellular mechanical properties influence cellular functions across pathological and physiological systems. The observation of these mechanical properties is limited in part by methods with a low throughput of acquisition or with low accessibility. To overcome these limitations, we have designed, developed, validated, and optimized a microfluidic cellular deformation system (MCDS) capable of mechanotyping suspended cells on a population level at a high throughput rate of ∼300 cells pers second.

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Article Synopsis
  • Cells in confined spaces face mechanical challenges that impact their migration, but the exact effects on their migration machinery are not fully understood.
  • Research shows that a protein called anillin, which regulates cytokinesis, is retained in the cytoplasm during interphase and is recruited to the edges of cells when they migrate in confined environments.
  • Anillin works alongside another protein, Ect2, to enhance muscle contractility inside cells, which is crucial for effective invasion and movement in cancer progression.
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Keratins are an integral part of cell structure and function. Here, it is shown that ectopic expression of a truncated isoform of keratin 81 (tKRT81) in breast cancer is upregulated in metastatic lesions compared to primary tumors and patient-derived circulating tumor cells, and is associated with more aggressive subtypes. tKRT81 physically interacts with keratin 18 (KRT18) and leads to changes in the cytosolic keratin intermediate filament network and desmosomal plaque formation.

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  • Metastasis is responsible for around 90% of breast cancer deaths, with microtentacles (McTNs) playing a key role in this process, particularly in the aggressive triple-negative breast cancer (TNBC) subtype which lacks effective targeted therapies.
  • The study focused on isolating viable circulating tumor cells (CTCs) from 20 TNBC patients to assess their response to the drug vinorelbine, finding that this treatment led to a significant increase in CTC numbers and induced apoptosis in these cancer cells.
  • Results indicated that vinorelbine not only triggered cell death but also decreased specific markers (like PD-L1) and disrupted McTNs, highlighting a promising method
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The histiocytoses comprise a histopathologically and clinically diverse group of disorders bearing recurrent genomic alterations, commonly involving the BRAF gene and mitogen-activated protein kinase pathway. In the current study, a novel CLTC :: SYK fusion in 3 cases of a histopathologically distinct histiocytic neoplasm arising as solitary soft tissue lesions in children identified by next-generation sequencing and fluorescence in situ hybridization is described. Morphologically, all 3 neoplasms were composed of sheets of cells with round-oval nuclei and vacuolated eosinophilic cytoplasm but, in contrast to classic juvenile xanthogranuloma (JXG), Touton giant cells were absent.

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Levels of hydrogen peroxide are highly elevated in the breast tumor microenvironment compared to normal tissue. Production of hydrogen peroxide is implicated in the mechanism of action of many anticancer therapies. Several lines of evidence suggest hydrogen peroxide mediates breast carcinogenesis and metastasis, though the molecular mechanism remains poorly understood.

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The tumor microenvironment and wound healing after injury both contain extremely high concentrations of the extracellular signaling molecule, adenosine triphosphate (ATP) compared to normal tissue. P2Y2 receptor, an ATP-activated purinergic receptor, is typically associated with pulmonary, endothelial, and neurological cell signaling. Here we report its role and importance in breast epithelial cell signaling and how it is altered in metastatic breast cancer.

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  • Recent findings suggest that the protein obscurin is linked to breast cancer development, with its loss leading to increased cell survival, resistance to treatment, and higher metastasis rates.
  • Analysis of patient data shows that lower obscurin levels are associated with worse survival outcomes in breast cancer.
  • A newly discovered long non-coding RNA (lncRNA) regulates obscurin expression and has potential as a therapeutic target, as restoring obscurin in certain breast cancer cells significantly reduces cell movement and spread.*
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Cytoskeletal remodeling in circulating tumor cells (CTCs) facilitates metastatic spread. Previous oncology studies examine sustained aberrant calcium (Ca) signaling and cytoskeletal remodeling scrutinizing long-term phenotypes such as tumorigenesis and metastasis. The significance of acute Ca signaling in tumor cells that occur within seconds to minutes is overlooked.

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Cell migration regulates diverse (patho)physiological processes, including cancer metastasis. According to the Osmotic Engine Model, polarization of NHE1 at the leading edge of confined cells facilitates water uptake, cell protrusion and motility. The physiological relevance of the Osmotic Engine Model and the identity of molecules mediating cell rear shrinkage remain elusive.

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Collective cell migration is an umbrella term for a rich variety of cell behaviors, whose distinct character is important for biological function, notably for cancer metastasis. One essential feature of collective behavior is the motion of cells relative to their immediate neighbors. We introduce an AI-based pipeline to segment and track cell nuclei from phase-contrast images.

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Post-translational modifications (PTMs) of the microtubule network impart differential functions across normal cell types and their cancerous counterparts. The removal of the C-terminal tyrosine of α-tubulin (deTyr-Tub) as performed by the tubulin carboxypeptidase (TCP) is of particular interest in breast epithelial and breast cancer cells. The recent discovery of the genetic identity of the TCP to be a vasohibin () coupled with a small vasohibin-binding protein () allows for the functional effect of this tubulin PTM to be directly tested for the first time.

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Upregulation of Vimentin (VIM), alpha-Tubulin (TUB) and Detyrosinated tubulin (GLU) in circulating tumor cells (CTCs) derived from breast cancer patients is related to poor prognosis. In the current study we evaluated for the first time, these cytoskeletal proteins in sixty Non-Small Cell Lung Cancer (NSCLC) patients' CTCs (33 treatment-naïve and 27 pre-treated). Samples were isolated using the ISET platform and stained with a pancytokeratin (CK)/CD45/TUB, CK/GLU/VIM and CK/programmed death ligand 1 (PD-L1) combination of antibodies.

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Article Synopsis
  • Clinical cancer imaging typically looks at tumor growth instead of how tumors spread (metastasis), but this study shifts the focus to metastatic behaviors.
  • The drug Vinorelbine was shown to significantly reduce metastatic features like microtentacle formation and tumor cell clustering, extending metastatic survival in mice from 8 to 30 weeks without affecting primary tumor survival.
  • This research suggests that FDA-approved drugs targeting microtubules (like Vinorelbine) could potentially help prevent metastasis, highlighting a new avenue for cancer treatment that is often overlooked because of the current focus on tumor growth.
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Background: The development of chemoresistance to paclitaxel and carboplatin represents a major therapeutic challenge in ovarian cancer, a disease frequently characterized by malignant ascites and extrapelvic metastasis. Microtentacles (McTNs) are tubulin-based projections observed in detached breast cancer cells. In this study, we investigated whether ovarian cancers exhibit McTNs and characterized McTN biology.

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Purpose: Surgeons now have a variety of treatment options for Dupuytren's contracture including traditional partial fasciectomy (PF), percutaneous needle aponeurotomy (PNA), and collagenase (CCH) injection. An important factor in clinical decision making is the cost-effectiveness of the various modalities, as will be discussed in this article.

Methods: A literature search was performed by 2 independent reviewers.

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Recent evidence suggests that groups of cells are more likely to form clinically dangerous metastatic tumors, emphasizing the importance of understanding mechanisms underlying collective behavior. The emergent collective behavior of migrating cell sheets in vitro has been shown to be disrupted in tumorigenic cells but the connection between this behavior and in vivo tumorigenicity remains unclear. We use particle image velocimetry to measure a multidimensional migration phenotype for genetically defined human breast epithelial cell lines that range in their in vivo behavior from non-tumorigenic to aggressively metastatic.

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Calcium is a versatile element that participates in cell signaling for a wide range of cell processes such as death, cell cycle, division, migration, invasion, metabolism, differentiation, autophagy, transcription, and others. Specificity of calcium in each of these processes is achieved through modulation of intracellular calcium concentrations by changing the characteristics (amplitude/frequency modulation) or location (spatial modulation) of the signal. Breast cancer utilizes calcium signaling as an advantage for survival and progression.

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Article Synopsis
  • Mammosphere assays help identify cancer-initiating stem cells that can form spheres in a lab setting, but traditional methods lead to cell clumping, making it hard to measure true efficiency.
  • A new technique using lipid anchors was developed to reduce cell aggregation while allowing for free-floating growth, improving the accuracy of monitoring mammosphere formation.
  • This method resulted in a significantly higher percentage of clonal mammospheres and better size correlation compared to traditional low-attachment approaches, indicating more reliable assay outcomes.
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  • Changes in mechanical signals during tumor progression suggest potential therapeutic targets related to mechanotransduction.
  • Normal breast epithelial cells respond to mechanical stimuli with a two-part calcium signaling mechanism involving immediate calcium rise and prolonged influx driven by NADPH oxidase 2 and TRPM8 channels.
  • The presence of an oncogenic KRas mutation suppresses this calcium signaling, which may affect cancer cell responses in the tumor microenvironment and predict poor outcomes in certain breast cancer patients.
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Clinical scores, molecular markers and cellular phenotypes have been used to predict the clinical outcomes of patients with glioblastoma. However, their clinical use has been hampered by confounders such as patient co-morbidities, by the tumoral heterogeneity of molecular and cellular markers, and by the complexity and cost of high-throughput single-cell analysis. Here, we show that a microfluidic assay for the quantification of cell migration and proliferation can categorize patients with glioblastoma according to progression-free survival.

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The technical challenges of imaging non-adherent tumor cells pose a critical barrier to understanding tumor cell responses to the non-adherent microenvironments of metastasis, like the bloodstream or lymphatics. In this study, we optimized a microfluidic device (TetherChip) engineered to prevent cell adhesion with an optically-clear, thermal-crosslinked polyelectrolyte multilayer nanosurface and a terminal lipid layer that simultaneously tethers the cell membrane for improved spatial immobilization. Thermal imidization of the TetherChip nanosurface on commercially-available microfluidic slides allows up to 98% of tumor cell capture by the lipid tethers.

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Mechanotransduction is the interpretation of physical cues by cells through mechanosensation mechanisms that elegantly translate mechanical stimuli into biochemical signaling pathways. While mechanical stress and their resulting cellular responses occur in normal physiologic contexts, there are a variety of cancer-associated physical cues present in the tumor microenvironment that are pathological in breast cancer. Mechanistic in vitro data and in vivo evidence currently support three mechanical stressors as mechanical modifiers in breast cancer that will be the focus of this review: stiffness, interstitial fluid pressure, and solid stress.

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