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result(s) for
"Doe, Aaron"
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Low HER2 expression in normal breast epithelium enables dedifferentiation and malignant transformation via chromatin opening
2023
Overexpression of the HER2 protein in breast cancer patients is a predictor of poor prognosis and resistance to therapies. We used an inducible breast cancer transformation system that allows investigation of early molecular changes. HER2 overexpression to similar levels as those observed in a subtype of HER2-positive breast cancer patients induced transformation of MCF10A cells and resulted in gross morphological changes, increased anchorage-independent growth of cells, and altered the transcriptional programme of genes associated with oncogenic transformation. Global phosphoproteomic analysis during HER2 induction predominantly detected an increase in protein phosphorylation. Intriguingly, this correlated with chromatin opening, as measured by ATAC-seq on acini isolated from 3D cell culture. HER2 overexpression resulted in opening of many distal regulatory regions and promoted reprogramming-associated heterogeneity. We found that a subset of cells acquired a dedifferentiated breast stem-like phenotype, making them likely candidates for malignant transformation. Our data show that this population of cells, which counterintuitively enriches for relatively low HER2 protein abundance and increased chromatin accessibility, possesses transformational drive, resulting in increased anchorage-independent growth in vitro compared to cells not displaying a stem-like phenotype.
Journal Article
Selective enrichment of plasma cell-free messenger RNA in cancer-associated extracellular vesicles
by
Demir, Emek
,
Spiliotopoulos, Elias
,
Mills, Gordon
in
631/67/1504/1610/4029
,
631/67/1612/1350
,
631/67/1857
2023
Extracellular vesicles (EVs) have been shown as key mediators of extracellular small RNA transport. However, carriers of cell-free messenger RNA (cf-mRNA) in human biofluids and their association with cancer remain poorly understood. Here, we performed a transcriptomic analysis of size-fractionated plasma from lung cancer, liver cancer, multiple myeloma, and healthy donors. Morphology and size distribution analysis showed the successful separation of large and medium particles from other soluble plasma protein fractions. We developed a strategy to purify and sequence ultra-low amounts of cf-mRNA from particle and protein enriched subpopulations with the implementation of RNA spike-ins to control for technical variability and to normalize for intrinsic drastic differences in cf-mRNA amount carried in each plasma fraction. We found that the majority of cf-mRNA was enriched and protected in EVs with remarkable stability in RNase-rich environments. We observed specific enrichment patterns of cancer-associated cf-mRNA in each particle and protein enriched subpopulation. The EV-enriched differentiating genes were associated with specific biological pathways, such as immune systems, liver function, and toxic substance regulation in lung cancer, liver cancer, and multiple myeloma, respectively. Our results suggest that dissecting the complexity of EV subpopulations illuminates their biological significance and offers a promising liquid biopsy approach.
Fractionation and characterization of cell-free mRNA carriers - mostly EVs - from various human plasma samples leads to identification of cancer-specific EV enrichment patterns
Journal Article
Single-cell RNA sequencing reveals different cellular states in malignant cells and the tumor microenvironment in primary and metastatic ER-positive breast cancer
2025
Metastatic breast cancer remains largely incurable, and the mechanisms driving the transition from primary to metastatic breast cancer remain elusive. We analyzed the complex landscape of estrogen receptor (ER)-positive breast cancer primary and metastatic tumors using scRNA-seq data from twenty-three female patients with either primary or metastatic disease. By employing single-cell transcriptional profiling of unpaired patient samples, we sought to elucidate the genetic and molecular mechanisms underlying changes in the metastatic tumor ecosystem. We identified specific subtypes of stromal and immune cells critical to forming a pro-tumor microenvironment in metastatic lesions, including CCL2+ macrophages, exhausted cytotoxic T cells, and FOXP3+ regulatory T cells. Analysis of cell-cell communication highlights a marked decrease in tumor-immune cell interactions in metastatic tissues, likely contributing to an immunosuppressive microenvironment. In contrast, primary breast cancer samples displayed increased activation of the TNF-α signaling pathway via NF-kB, indicating a potential therapeutic target. Our study comprehensively characterizes the transcriptional landscape encompassing primary and metastatic breast cancer.
Journal Article
Endogenous Osteocyte-Osteoclast Signaling Enables Growth Factor-Free Bone Remodeling, Drug Response, and Cancer Invasion in a Nanoscale Calcified Bone-on-a-Chip Model
2025
Bone homeostasis depends on spatially orchestrated interactions among osteoclasts, osteoblasts, and osteocytes that are embedded within a unique extracellular matrix that is mineralized on the nanoscale to define the structure and function of bone. Reconstructing these interactions to enable autonomous cell differentiation and tissue remodeling has remained a significant challenge towards mimicking adequate bone physiology in-vitro. Here, we present an engineered model that spatially defines the paracrine communication of heterogeneous cell populations within bone tissue that support the rapid maturation of primary osteoblasts into osteocytes, the differentiation of macrophages into osteoclasts, and calcified tissue resorption within a mineralized cell-laden bone-like tissue. We demonstrate that nanoscale mineralization of cell-laden collagen hydrogels on-a-chip enhances osteoblast to osteocyte differentiation, whereas osteocytes in the matrix accelerate osteoclastogenesis and remodeling in a spatially defined manner without the need for exogenous growth factors. Osteocyte-dependent osteoclastogenesis on-a-chip outperformed conventional stimulation with RANKL and M-CSF, reproduced the clinical response of anti-resorptive drugs, and mimicked established tumor-bone interactions observed in invasive oral cancer. By replicating essential aspects of bone composition and function, this system provides a robust, self-regulated microphysiologic model to investigate bone remodeling, cancer-bone crosstalk, and therapeutic interventions.
Journal Article
Selective enrichment of plasma cell-free messenger RNA in cancer-associated extracellular vesicles
2022
Extracellular vesicles (EVs) have been shown as key mediators of extracellular small RNA transport. However, carriers of cell-free messenger RNA (cf-mRNA) in human biofluid and their association with cancer remain poorly understood. Here, we performed a transcriptomic analysis of size-fractionated plasma from lung cancer, liver cancer, multiple myeloma, and healthy donors. Morphology and size distribution analysis showed the successful separation of medium and small EVs and non-vesicular carriers. We developed a strategy to purify and sequence ultra-low amounts of cf-mRNA from vesicular and non-vesicular subpopulations with the implementation of RNA spike-ins to control for technical variability and to normalize for intrinsic drastic differences in the amount of cf-mRNA carried in each plasma fraction. We found that the majority of cf-mRNA was enriched and protected in EVs with remarkable stability in RNase-rich environments. We observed specific enrichment patterns of cancer-associated cf-mRNA in each vesicular and non-vesicular subpopulation. The EV-enriched differentiating genes were associated with specific biological pathways, such as immune systems, liver function, and toxic substance regulation in lung cancer, liver cancer, and multiple myeloma, respectively. Our results suggest that dissecting the complexity of EVs subpopulations illuminates their biological significance and offers a promising liquid biopsy approach. Competing Interest Statement The authors have declared no competing interest.
Perivascular cells function as mechano-structural sensors of vascular capillaries
by
Dimitriadis, Emilios
,
Chen, Christopher S
,
Bays, Jennifer
in
Angiogenesis
,
Bioengineering
,
Blood vessels
2024
A wide range of conditions, including chronic inflammatory diseases and cancer, are characterized by the fibrotic microarchitecture and increased stiffness of collagen type I extracellular matrix. These conditions are typically accompanied by altered vascular function, including vessel leakiness, abnormal capillary morphology and stability. The dynamic cell-matrix interactions that regulate vascular function in healthy tissues have been well documented. However, our understanding of how the gradual mechanical and structural alterations in collagen type I affect vascular homeostasis remains elusive, especially as a function of the interactions between endothelial and perivascular cell with the altered matrix. Here we hypothesized that perivascular cells might function as mechano-structural sensors of the microvasculature by mediating the interaction between endothelial cells and altered collagen type I. To test that, we utilized an organotypic model of perivascular cell-supported vascular capillaries in collagen scaffolds of controlled microarchitecture and mechanics. Our results demonstrate that capillaries cultured in soft reticular collagen exhibited consistent pericyte differentiation, endothelial cell-cell junctions, and barrier function. In contrast, capillaries embedded in stiff and bundled collagen fibrils to mimic a more fibrotic matrix induced abluminal migration of perivascular cells, increased leakage, and marked expression of vascular remodeling and inflammatory markers. These patterns, however, were only observed when endothelial capillaries were engineered with perivascular cells. Silencing of NOTCH3, a mediator of endothelial-perivascular cell communication, largely re-established normal vascular morphology and function. In summary, our findings point to a novel mechanism of perivascular regulation of vascular dysfunction in fibrotic tissues which may have important implications for anti-angiogenic and anti-fibrotic therapies in cancer, chronic inflammatory diseases and regenerative medicine.Competing Interest StatementThe authors have declared no competing interest.
Unpiloted Aerial Systems (UASs) Application for Tornado Damage Surveys
2019
Specifically, flight operations can be conducted and automated using a variety of flights apps (e.g., Pix4D, DroneDeploy) and should be cognizant of lighting conditions to minimize data loss due to shadows. Because flight operations are often limited to a battery life of 30 min or less (fixed-wing UASs excluded), it is important to have several batteries and a charging platform on-site. Disaster zones are highly sensitive and stressful spaces where emergency managers and local law enforcement are often overloaded with incoming information while executing their operations. [...]coordinating with emergency managers, NOAA personnel, and other agencies is key to (a) assisting these organizations with regard to their specific needs, (b) gaining access in these sensitive areas, and (c) staying up to date on airspace restrictions and other emergency management operations. Policies outside the United States can be very restrictive, making it extremely difficult to operate in some countries (as seen in Europe). [...]organizations outside of the United States (e.g., TORRO) would need to consult their specific laws. [...]data-sharing and decision-support platforms should be easily accessible and capable of handling large volumes of data, and ideally would include a collaborative mapping platform for visualizing and sharing large datasets with multiple agencies to facilitate better decision-making.
Journal Article
Skin-interfaced biosensors for advanced wireless physiological monitoring in neonatal and pediatric intensive-care units
2020
Standard clinical care in neonatal and pediatric intensive-care units (NICUs and PICUs, respectively) involves continuous monitoring of vital signs with hard-wired devices that adhere to the skin and, in certain instances, can involve catheter-based pressure sensors inserted into the arteries. These systems entail risks of causing iatrogenic skin injuries, complicating clinical care and impeding skin-to-skin contact between parent and child. Here we present a wireless, non-invasive technology that not only offers measurement equivalency to existing clinical standards for heart rate, respiration rate, temperature and blood oxygenation, but also provides a range of important additional features, as supported by data from pilot clinical studies in both the NICU and PICU. These new modalities include tracking movements and body orientation, quantifying the physiological benefits of skin-to-skin care, capturing acoustic signatures of cardiac activity, recording vocal biomarkers associated with tonality and temporal characteristics of crying and monitoring a reliable surrogate for systolic blood pressure. These platforms have the potential to substantially enhance the quality of neonatal and pediatric critical care.
Soft electronic patches worn on the skin of infants or children in intensive-care units have a wide range of capabilities in aiding critical care, including monitoring of hemodynamic parameters, cardiac activity, movement and crying.
Journal Article
In-Datacenter Performance Analysis of a Tensor Processing Unit
by
Agrawal, Gaurav
,
Ho, C Richard
,
Bhatia, Suresh
in
Data centers
,
Graphics processing units
,
Inference
2017
Many architects believe that major improvements in cost-energy-performance must now come from domain-specific hardware. This paper evaluates a custom ASIC---called a Tensor Processing Unit (TPU)---deployed in datacenters since 2015 that accelerates the inference phase of neural networks (NN). The heart of the TPU is a 65,536 8-bit MAC matrix multiply unit that offers a peak throughput of 92 TeraOps/second (TOPS) and a large (28 MiB) software-managed on-chip memory. The TPU's deterministic execution model is a better match to the 99th-percentile response-time requirement of our NN applications than are the time-varying optimizations of CPUs and GPUs (caches, out-of-order execution, multithreading, multiprocessing, prefetching, ...) that help average throughput more than guaranteed latency. The lack of such features helps explain why, despite having myriad MACs and a big memory, the TPU is relatively small and low power. We compare the TPU to a server-class Intel Haswell CPU and an Nvidia K80 GPU, which are contemporaries deployed in the same datacenters. Our workload, written in the high-level TensorFlow framework, uses production NN applications (MLPs, CNNs, and LSTMs) that represent 95% of our datacenters' NN inference demand. Despite low utilization for some applications, the TPU is on average about 15X - 30X faster than its contemporary GPU or CPU, with TOPS/Watt about 30X - 80X higher. Moreover, using the GPU's GDDR5 memory in the TPU would triple achieved TOPS and raise TOPS/Watt to nearly 70X the GPU and 200X the CPU.