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Understanding the complex biomechanical tumor microenvironment (TME) is of critical importance in developing the next generation of anti-cancer treatment strategies. This is especially true in epithelial ovarian cancer (EOC), the deadliest of the gynecologic cancers due to recurrent disease or chemoresistance. However, current models of EOC progression provide little control or ability to monitor how changes in biomechanical parameters alter EOC cell behaviors. In this study, we present a microfluidic device designed to permit biomechanical investigations of the ovarian TME. Using this microtissue system, we describe how biomechanical stimulation in the form of tensile strains upregulate phosphorylation of HSP27, a heat shock protein implicated in ovarian cancer chemoresistance. Furthermore, EOC cells treated with strain demonstrate decreased response to paclitaxel in the in vitro vascularized TME model. The results provide a direct link to biomechanical regulation of HSP27 as a mediator of EOC chemoresistance, possibly explaining the failure of such therapies in some patients. The work presented here lays a foundation to elucidating mechanobiological regulation of EOC progression, including chemoresistance and could provide novel targets for anti-cancer therapeutics.
Assuntos
Neoplasias Epiteliais e Glandulares , Neoplasias Ovarianas , Feminino , Humanos , Carcinoma Epitelial do Ovário/patologia , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP27/metabolismo , Neoplasias Ovarianas/patologia , Paclitaxel/farmacologia , Microambiente TumoralRESUMO
With the increasing prevalence of antimicrobial-resistant bacterial infections, there is great interest in using lytic bacteriophages (phages) to treat such infections. However, the factors that govern bacteriophage pharmacokinetics in vivo remain poorly understood. Here, we have examined the contribution of neutrophils, the most abundant phagocytes in the body, to the pharmacokinetics of intravenously administered bacteriophage in uninfected mice. A single dose of LPS-5, an antipseudomonal bacteriophage recently used in human clinical trials, was administered intravenously to both wild-type BALB/c and neutropenic ICR mice. Phage concentrations were assessed in peripheral blood and spleen at 0.5, 1, 2, 4, 8, 12, and 24 hours after administration by plaque assay and qPCR. We observed that the phage clearance is only minimally affected by neutropenia. Indeed, the half-life of phages in blood in BALB/c and ICR mice is 3.45 and 3.66 hours, respectively. These data suggest that neutrophil-mediated phagocytosis is not a major determinant of phage clearance. Conversely, we observed a substantial discrepancy in circulating phage levels over time when measured by qPCR versus plaque assay, suggesting that substantial functional inactivation of circulating phages occurs over time. These data indicate that circulating factors, but not neutrophils, inactivate intravenously administered phages.
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BACKGROUND: Angiogenesis, or the growth of new vasculature from existing blood vessels, is widely considered a primary hallmark of cancer progression. When a tumor is small, diffusion is sufficient to receive essential nutrients; however, as the tumor grows, a vascular supply is needed to deliver oxygen and nutrients into the increasing mass. Several anti-angiogenic cancer therapies target VEGF and the receptor VEGFR-2, which are major promoters of blood vessel development. Unfortunately, many of these cancer treatments fail to completely stop angiogenesis in the tumor microenvironment (TME). Since these therapies focus on the biochemical activation of VEGFR-2 via VEGF ligand binding, we propose that mechanical cues, particularly those found in the TME, may be a source of VEGFR-2 activation that promotes growth of blood vessel networks even in the presence of VEGF and VEGFR-2 inhibitors. RESULTS: In this paper, we analyzed phosphorylation patterns of VEGFR-2, particularly at Y1054/Y1059 and Y1214, stimulated via either VEGF or biomechanical stimulation in the form of tensile strains. Our results show prolonged and enhanced activation at both Y1054/Y1059 and Y1214 residues when endothelial cells were stimulated with strain, VEGF, or a combination of both. We also analyzed Src expression, which is downstream of VEGFR-2 and can be activated through strain or the presence of VEGF. Finally, we used fibrin gels and microfluidic devices as 3D microtissue models to simulate the TME. We determined that regions of mechanical strain promoted increased vessel growth, even with VEGFR-2 inhibition through SU5416. CONCLUSIONS: Overall, understanding both the effects that biomechanical and biochemical stimuli have on VEGFR-2 activation and angiogenesis is an important factor in developing effective anti-angiogenic therapies. This paper shows that VEGFR-2 can be mechanically activated through strain, which likely contributes to increased angiogenesis in the TME. These proof-of-concept studies show that small molecular inhibitors of VEGFR-2 do not fully prevent angiogenesis in 3D TME models when mechanical strains are introduced.
Assuntos
Neoplasias , Receptor 2 de Fatores de Crescimento do Endotélio Vascular , Humanos , Células Endoteliais/metabolismo , Neoplasias/metabolismo , Transdução de Sinais , Microambiente Tumoral , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
Extensive efforts are underway to develop bacteriophages as therapies against antibiotic-resistant bacteria. However, these efforts are confounded by the instability of phage preparations and a lack of suitable tools to assess active phage concentrations over time. In this study, we use dynamic light scattering (DLS) to measure changes in phage physical state in response to environmental factors and time, finding that phages tend to decay and form aggregates and that the degree of aggregation can be used to predict phage bioactivity. We then use DLS to optimize phage storage conditions for phages from human clinical trials, predict bioactivity in 50-y-old archival stocks, and evaluate phage samples for use in a phage therapy/wound infection model. We also provide a web application (Phage-Estimator of Lytic Function) to facilitate DLS studies of phages. We conclude that DLS provides a rapid, convenient, and nondestructive tool for quality control of phage preparations in academic and commercial settings.
RESUMO
The RNA-binding protein TDP-43 is associated with mRNA processing and transport from the nucleus to the cytoplasm. TDP-43 localizes in the nucleus as well as accumulating in cytoplasmic condensates such as stress granules. Aggregation and formation of amyloid-like fibrils of cytoplasmic TDP-43 are hallmarks of numerous neurodegenerative diseases, most strikingly present in >90% of amyotrophic lateral sclerosis (ALS) patients. If excessive accumulation of cytoplasmic TDP-43 causes, or is caused by, neurodegeneration is presently not known. In this work, we use molecular dynamics simulations at multiple resolutions to explore TDP-43 self- and cross-interaction dynamics. A full-length molecular model of TDP-43, all 414 amino acids, was constructed from select structures of the protein functional domains (N-terminal domain, and two RNA recognition motifs, RRM1 and RRM2) and modeling of disordered connecting loops and the low complexity glycine-rich C-terminus domain. All-atom CHARMM36m simulations of single TDP-43 proteins served as guides to construct a coarse-grained Martini 3 model of TDP-43. The Martini model and a coarser implicit solvent C⺠model, optimized for disordered proteins, were subsequently used to probe TDP-43 interactions; self-interactions from single-chain full-length TDP-43 simulations, cross-interactions from simulations with two proteins and simulations with assemblies of dozens to hundreds of proteins. Our findings illustrate the utility of different modeling scales for accessing TDP-43 molecular-level interactions and suggest that TDP-43 has numerous interaction preferences or patterns, exhibiting an overall strong, but dynamic, association and driving the formation of biomolecular condensates.
Assuntos
Esclerose Lateral Amiotrófica , Humanos , Domínios Proteicos , Esclerose Lateral Amiotrófica/metabolismo , Proteínas de Ligação a DNA/metabolismo , Simulação de Dinâmica Molecular , AmiloideRESUMO
Polymorphic 2D materials have recently emerged as promising candidates for use in nanoelectronic devices by way of their ability to undergo structural phase transformations induced by external fields. Under cyclic transformations, however, induced interfacial defects may proliferate and compromise the system properties. Herein, we first employ geometric analysis to classify such defects generated during the 2H â 1T and 2H â 1T' transformations in group VI transition-metal dichalcogenide monolayers. Then, simulations of a mesoscale model with atomistic spatial resolution are conducted to assess the proliferation of such defects during cyclic 2H â 1T transformations. It is shown that defect densities reach a steady state, with the 2H phase remaining more pristine than the 1T and 1T' states. We expect that the effects of these defects on the device performance are application-dependent and will require further inquiry.
RESUMO
Extensive efforts are underway to develop bacteriophages as therapies against antibiotic-resistant bacteria. However, these efforts are confounded by the instability of phage preparations and a lack of suitable tools to assess active phage concentrations over time. Here, we use Dynamic Light Scattering (DLS) to measure changes in phage physical state in response to environmental factors and time, finding that phages tend to decay and form aggregates and that the degree of aggregation can be used to predict phage bioactivity. We then use DLS to optimize phage storage conditions for phages from human clinical trials, predict bioactivity in 50-year-old archival stocks, and evaluate phage samples for use in a phage therapy/wound infection model. We also provide a web-application (Phage-ELF) to facilitate DLS studies of phages. We conclude that DLS provides a rapid, convenient, and non-destructive tool for quality control of phage preparations in academic and commercial settings.
RESUMO
Jumbo phages such as Pseudomonas aeruginosa ФKZ have potential as antimicrobials and as a model for uncovering basic phage biology. Both pursuits are currently limited by a lack of genetic engineering tools due to a proteinaceous 'phage nucleus' structure that protects from DNA-targeting CRISPR-Cas tools. To provide reverse-genetics tools for DNA jumbo phages from this family, we combined homologous recombination with an RNA-targeting CRISPR-Cas13a enzyme and used an anti-CRISPR gene (acrVIA1) as a selectable marker. We showed that this process can insert foreign genes, delete genes and add fluorescent tags to genes in the ФKZ genome. Fluorescent tagging of endogenous gp93 revealed that it is ejected with the phage DNA while deletion of the tubulin-like protein PhuZ surprisingly had only a modest impact on phage burst size. Editing of two other phages that resist DNA-targeting CRISPR-Cas systems was also achieved. RNA-targeting Cas13a holds great promise for becoming a universal genetic editing tool for intractable phages, enabling the systematic study of phage genes of unknown function.
Assuntos
Bacteriófagos , Bacteriófagos/genética , Sistemas CRISPR-Cas , Edição de Genes , Engenharia Genética , RNARESUMO
Multi-specific and long-lasting T cell immunity have been recognized as indicators for long term protection against pathogens including the novel coronavirus SARS-CoV-2, the causative agent of the COVID-19 pandemic. Functional significance of peripheral memory T cells in individuals recovering from COVID-19 (COVID-19 + ) are beginning to be appreciated; but little is known about lung resident memory T cells (lung TRM) in SARS-CoV-2 infection. Here, we utilize a perfused three dimensional (3D) human lung tissue model and identify pre-existing local T cell immunity against SARS-CoV-2 proteins in lung tissues. We report ex vivo maintenance of functional multi-specific IFN-γ secreting lung TRM in COVID-19 + and their induction in lung tissues of vaccinated COVID-19 + . Importantly, we identify SARS-CoV-2 peptide-responding B cells and IgA + plasma cells in lung tissues of COVID-19 + in ex vivo 3D-tissue models. Our study highlights the importance of balanced and local anti-viral immune response in the lung with persistent induction of TRM and IgA + plasma cells for future protection against SARS-CoV-2 infection. Further, our data suggest that inclusion of multiple viral antigens in vaccine approaches may broaden the functional profile of memory T cells to combat the severity of coronavirus infection.
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Among gynecologic malignancies, ovarian cancer (OC) has the poorest survival rate, and its clinical management remains challenging due to the high rate of recurrence and chemoresistance. Improving survival for these patients is critical, although this requires the ability to translate preclinical studies to actual patient care: bench to bedside and back. Our objective was to develop a preclinical model that accurately represents tumor biology and its microenvironment. We utilized SKOV-3, OVCAR-8, and CS-99 cell lines to show that this model was suitable for in vitro assessment of cell proliferation. We tested OC cells independently and in co-culture with cancer associated fibroblasts (CAFs) or immune cells. Additionally, we used patient-derived ovarian carcinoma and carcinosarcoma samples to show that the system maintains the histologic morphology of the primary tissue after 7 days. Moreover, we tested the response to chemotherapy using both cell lines and patient-derived tumor specimens and confirmed that cell death was significantly higher in the treated group compared to the vehicle group. Finally, we immune profiled the 3-D model containing patient tissue after several days in the bioreactor system and revealed that the immune populations are still present. Our data suggest that this model is a suitable preclinical model to aid in research that will ultimately impact the treatment of patients with gynecologic cancer.
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INTRODUCTION: Wound healing affects millions of people annually. After injury, keratinocytes from the wound edge proliferate, migrate, and differentiate to recapitulate the 3-dimensional (3D) structure needed to provide a barrier function. If the wound is too large, skin grafting may be required. We are interested in discovering novel strategies to enhance the wound healing process. It may be possible to recreate a viable and histologically accurate skin tissue using 3D printing. We hypothesize that keratinocytes and dermal fibroblasts can be bioprinted into a viable skin substitute. METHODS: Adult human dermal fibroblasts (HDFa) and adult human epidermal keratinocytes (HEKa) were cultured and subsequently printed with a 3D bioprinter within a hydrogel scaffold. After printing the HDFa and HEKa separately, cell viability and histological appearance were determined by sectioning the printed tissue and performing hematoxylin and eosin staining. The stained histological sections were analyzed for tissue morphology. RESULTS: The HEKa and HDFa cells suspended in the hydrogel were successfully printed into 3D scaffolds that resembled skin with hematoxylin and eosin staining. CONCLUSIONS: The HEKa and HDFa cells can be grown on 3D-printed hydrogels successfully. In addition, HEKa and HDFa cells can survive and grow when suspended in a hydrogel and 3D printed. Future potential applications of these results could lead to the creation of viable skin tissue for wound healing and surgical repair.
Assuntos
Pele Artificial , Células Cultivadas , Fibroblastos , Humanos , Queratinócitos , Impressão Tridimensional , Pele , Engenharia TecidualRESUMO
Human induced-pluripotent stem cells (hiPSCs) can be efficiently differentiated into cardiomyocytes (hiPSC-CMs) via the GiWi method, which uses small-molecule inhibitors of glycogen synthase kinase (GSK) and tankyrase to first activate and then suppress Wnt signaling. However, this method is typically conducted in 6-well culture plates with two-dimensional (2D) cell sheets, and consequently, cannot be easily scaled to produce the large numbers of hiPSC-CMs needed for clinical applications. Cell suspensions are more suitable than 2D systems for commercial biomanufacturing, and suspended hiPSCs form free-floating aggregates (i.e., spheroids) that can also be differentiated into hiPSC-CMs. Here, we introduce a protocol for differentiating suspensions of hiPSC spheroids into cardiomyocytes that is based on the GiWi method. After optimization based on cardiac troponin T staining, the purity of hiPSC-CMs differentiated via our novel protocol exceeded 98% with yields of about 1.5 million hiPSC-CMs/mL and less between-batch purity variability than hiPSC-CMs produced in 2D cultures; furthermore, the culture volume could be increased â¼10-fold to 30 mL with no need for re-optimization, which suggests that this method can serve as a framework for large-scale hiPSC-CM production.
RESUMO
Tumor-stromal interactions within the tumor microenvironment (TME) influence lung cancer progression and response to therapeutic interventions, yet traditional in vitro studies fail to replicate the complexity of these interactions. Herein, we developed three-dimensional (3D) lung tumor models that mimic the human TME and demonstrate tumor-stromal crosstalk mediated by extracellular vesicles (EVs). EVs released by tumor cells, independent of p53 status, and fibroblasts within the TME mediate immunomodulatory effects; specifically, monocyte/macrophage polarization to a tumor-promoting M2 phenotype within this 3D-TME. Additionally, immune checkpoint inhibition in a 3D model that included T cells showed an inhibition of tumor growth and reduced hypoxia within the TME. Thus, perfused 3D tumor models incorporating diverse cell types provide novel insights into EV-mediated tumor-immune interactions and immune-modulation for existing and emerging cancer therapies.
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The ability to tune the local electronic transport properties of group VI transition metal dichalcogenide (TMD) monolayers by strain-induced structural phase transformations ("phase programming") has stimulated much interest in the potential applications of such layers as ultrathin programmable and dynamically switchable nanoelectronics components. In this manuscript, we propose a new approach toward controlling TMD monolayer phases by employing macroscopic in-plane strains to amplify heterogeneous strains arising from tailored, spatially extended defects within the monolayer. The efficacy of our proposed approach is demonstrated via numerical simulations of emerging domains localized around arrays of holes, grain boundaries, and compositional heterointerfaces. Quantitative relations between the macroscopic strains required, spatial resolution of domain patterns, and defect configurations are developed. In particular, the introduction of arrays of holes is identified as the most feasible phase programming route.
RESUMO
Engineered cardiac tissues fabricated from human induced pluripotent stem cells (hiPSCs) show promise for ameliorating damage from myocardial infarction, while also restoring function to the damaged left ventricular (LV) myocardium. For these constructs to reach their clinical potential, they need to be of a clinically relevant volume and thickness, and capable of generating synchronous and forceful contraction to assist the pumping action of the recipient heart. Design prerequisites include a structure thickness sufficient to produce a beneficial contractile force, prevascularization to overcome diffusion limitations and sufficient structural development to allow for maximal cell communication. Previous attempts to meet these prerequisites have been hindered by lack of oxygen and nutrient transport due to diffusion limits (100-200 µm) resulting in necrosis. This study employs a layer-by-layer (LbL) fabrication method to produce cardiac tissue constructs that meet these design prerequisites and mimic normal myocardium in form and function. Thick (>2 mm) cardiac tissues created from hiPSC-derived cardiomyocytes, -endothelial cells (ECs) and -fibroblasts (FBs) were assessed, in vitro, over a 4-week period for viability (<6% necrotic cells), cell morphology and functionality. Functional performance assessment showed enhanced t-tubule network development, gap junction communication as well as previously unseen, physiologically relevant conduction velocities (CVs) (>30 cm/s). These results demonstrate that LbL fabrication can be utilized successfully to create prevascularized, functional cardiac tissue constructs from hiPSCs for potential therapeutic applications.
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Cellular exosome-mediated crosstalk in tumor microenvironment (TME) is a critical component of anti-tumor immune responses. In addition to particle size, exosome transport and uptake by target cells is influenced by physical and physiological factors, including interstitial fluid pressure, and exosome concentration. These variables differ under both normal and pathological conditions, including cancer. The transport of exosomes in TME is governed by interstitial flow and diffusion. Based on these determinants, mathematical models were adapted to simulate the transport of exosomes in the TME with specified exosome release rates from the tumor cells. In this study, the significance of spatial relationship in exosome-mediated intercellular communication was established by treating their movement in the TME as a continuum using a transport equation, with advection due to interstitial flow and diffusion due to concentration gradients. To quantify the rate of release of exosomes by biomechanical forces acting on the tumor cells, we used a transwell platform with confluent triple negative breast cancer cells 4T1.2 seeded in BioFlex plates exposed to an oscillatory force. Exosome release rates were quantified from 4T1.2 cells seeded at the bottom of the well following the application of either no force or an oscillatory force, and these rates were used to model exosome transport in the transwell. The simulations predicted that a larger number of exosomes reached the membrane of the transwell for 4T1.2 cells exposed to the oscillatory force when compared to controls. Additionally, we simulated the interstitial fluid flow and exosome transport in a 2-dimensional TME with macrophages, T cells, and mixtures of these two populations at two different stages of a tumor growth. Computational simulations were carried out using the commercial computational simulation package, ANSYS/Fluent. The results of this study indicated higher exosome concentrations and larger interstitial fluid pressure at the later stages of the tumor growth. Quantifying the release of exosomes by cancer cells, their transport through the TME, and their concentration in TME will afford a deeper understanding of the mechanisms of these interactions and aid in deriving predictive models for therapeutic intervention.
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Few models exist for studying neuroendocrine tumors (NETs), and there are mounting concerns that the currently available array of cell lines is not representative of NET biology. The lack of stable patient-derived NET xenograft models further limits the scientific community's ability to make conclusions about NETs and their response to therapy in patients. To address these limitations, we propose the use of an ex vivo 3D flow-perfusion bioreactor system for culturing and studying patient-derived NET surrogates. Herein, we demonstrate the utility of the bioreactor system for culturing NET surrogates and provide methods for evaluating the efficacy of therapeutic agents on human NET cell line xenograft constructs and patient-derived NET surrogates. We also demonstrate that patient-derived NET tissues can be propagated using the bioreactor system and investigate the near-infrared (NIR) dye IR-783 for its use in monitoring their status within the bioreactor. The results indicate that the bioreactor system and similar 3D culture models may be valuable tools for culturing patient-derived NETs and monitoring their response to therapy ex vivo.
Assuntos
Reatores Biológicos/estatística & dados numéricos , Técnicas de Cultura de Células/métodos , Neoplasias Intestinais/patologia , Neoplasias Pulmonares/patologia , Modelos Biológicos , Tumores Neuroendócrinos/patologia , Neoplasias Pancreáticas/patologia , Neoplasias Gástricas/patologia , Neoplasias da Glândula Tireoide/patologia , Animais , Humanos , Camundongos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cardiac tissue surrogates show promise for restoring mechanical and electrical function in infarcted left ventricular (LV) myocardium. For these cardiac surrogates to be usefulin vivo, they are required to support synchronous and forceful contraction over the infarcted region. These design requirements necessitate a thickness sufficient to produce a useful contractile force, an area large enough to cover an infarcted region, and prevascularization to overcome diffusion limitations. Attempts to meet these requirements have been hampered by diffusion limits of oxygen and nutrients (100-200 µm) leading to necrotic regions. This study demonstrates a novel layer-by-layer (LbL) fabrication method used to produce tissue surrogates that meet these requirements and mimic normal myocardium in form and function. Thick (1.5-2 mm) LbL cardiac tissues created from human induced pluripotent stem cell-derived cardiomyocytes and endothelial cells were assessed,in vitro, over a 4-week period for viability (<5.6 ± 1.4% nectrotic cells), cell morphology, viscoelastic properties and functionality. Viscoelastic properties of the cardiac surrogates were determined via stress relaxation response modeling and compared to native murine LV tissue. Viscoelastic characterization showed that the generalized Maxwell model of order 4 described the samples well (0.7 Assuntos
Células Endoteliais
, Células-Tronco Pluripotentes Induzidas
, Animais
, Humanos
, Camundongos
, Miocárdio
, Miócitos Cardíacos
, Engenharia Tecidual/métodos
RESUMO
CRISPR-Cas technologies have enabled programmable gene editing in eukaryotes and prokaryotes. However, the leading Cas9 and Cas12a enzymes are limited in their ability to make large deletions. Here, we used the processive nuclease Cas3, together with a minimal Type I-C Cascade-based system for targeted genome engineering in bacteria. DNA cleavage guided by a single CRISPR RNA generated large deletions (7-424 kilobases) in Pseudomonas aeruginosa with near-100% efficiency, while Cas9 yielded small deletions and point mutations. Cas3 generated bidirectional deletions originating from the programmed site, which was exploited to reduce the P. aeruginosa genome by 837 kb (13.5%). Large deletion boundaries were efficiently specified by a homology-directed repair template during editing with Cascade-Cas3, but not Cas9. A transferable 'all-in-one' vector was functional in Escherichia coli, Pseudomonas syringae and Klebsiella pneumoniae, and endogenous CRISPR-Cas use was enhanced with an 'anti-anti-CRISPR' strategy. P. aeruginosa Type I-C Cascade-Cas3 (PaeCas3c) facilitates rapid strain manipulation with applications in synthetic biology, genome minimization and the removal of large genomic regions.
Assuntos
Proteína 9 Associada à CRISPR/metabolismo , Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , DNA Helicases/metabolismo , Proteínas de Escherichia coli/metabolismo , Edição de Genes/métodos , Engenharia Genética/métodos , Sequência de Bases/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Escherichia coli/genética , Genoma Bacteriano/genética , Klebsiella pneumoniae/genética , Pseudomonas aeruginosa/genética , Pseudomonas syringae/genética , Deleção de Sequência/genéticaRESUMO
Breast cancer (BCa) proliferates within a complex, three-dimensional microenvironment amid heterogeneous biochemical and biophysical cues. Understanding how mechanical forces within the tumor microenvironment (TME) regulate BCa phenotype is of great interest. We demonstrate that mechanical strain enhanced the proliferation and migration of both estrogen receptor+ and triple-negative (TNBC) human and mouse BCa cells. Furthermore, a critical role for exosomes derived from cells subjected to mechanical strain in these pro-tumorigenic effects was identified. Exosome production by TNBC cells increased upon exposure to oscillatory strain (OS), which correlated with elevated cell proliferation. Using a syngeneic, orthotopic mouse model of TNBC, we identified that preconditioning BCa cells with OS significantly increased tumor growth and myeloid-derived suppressor cells (MDSCs) and M2 macrophages in the TME. This pro-tumorigenic myeloid cell enrichment also correlated with a decrease in CD8+ T cells. An increase in PD-L1+ exosome release from BCa cells following OS supported additive T cell inhibitory functions in the TME. The role of exosomes in MDSC and M2 macrophage was confirmed in vivo by cytotracking fluorescent exosomes, derived from labeled 4T1.2 cells, preconditioned with OS. In addition, in vivo internalization and intratumoral localization of tumor-cell derived exosomes was observed within MDSCs, M2 macrophages, and CD45-negative cell populations following direct injection of fluorescently-labeled exosomes. Our data demonstrate that exposure to mechanical strain promotes invasive and pro-tumorigenic phenotypes in BCa cells, indicating that mechanical strain can impact the growth and proliferation of cancer cell, alter exosome production by BCa, and induce immunosuppression in the TME by dampening anti-tumor immunity.