Browsing by Author "Bushnell, Grace G."

Now showing 1 - 7 of 7
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    Biomaterial Scaffolds as Pre-metastatic Niche Mimics Systemically Alter the Primary Tumor and Tumor Microenvironment
    (Wiley, 2018) Aguado, Brian A.; Hartfield, Rachel M.; Bushnell, Grace G.; Decker, Joseph T.; Azarin, Samira M.; Nanavati, Dhaval; Schipma, Matthew J.; Rao, Shreyas S.; Oakes, Robert S.; Zhang, Yining; Jeruss, Jacqueline S.; Shea, Lonnie D.; Northwestern University; University of Michigan; University of Alabama Tuscaloosa
    Primary tumor (PT) immune cells and pre-metastatic niche (PMN) sites are critical to metastasis. Recently, synthetic biomaterial scaffolds used as PMN mimics are shown to capture both immune and metastatic tumor cells. Herein, studies are performed to investigate whether the scaffold-mediated redirection of immune and tumor cells would alter the primary tumor microenvironment (TME). Transcriptomic analysis of PT cells from scaffold-implanted and mock-surgery mice identifies differentially regulated pathways relevant to invasion and metastasis progression. Transcriptomic differences are hypothesized to result from scaffold-mediated modulations of immune cell trafficking and phenotype in the TME. Culturing tumor cells with conditioned media generated from PT immune cells of scaffold-implanted mice decrease invasion in vitro more than two-fold relative to mock surgery controls and reduce activity of invasion-promoting transcription factors. Secretomic characterization of the conditioned media delineates interactions between immune cells in the TME and tumor cells, showing an increase in the pan-metastasis inhibitor decorin and a concomitant decrease in invasion-promoting chemokine (C-C motif) ligand 2 (CCL2) in scaffold-implanted mice. Flow cytometric and transcriptomic profiling of PT immune cells identify phenotypically distinct tumor-associated macrophages (TAMs) in scaffold-implanted mice, which may contribute to an invasion-suppressive TME. Taken together, this study demonstrates biomaterial scaffolds systemically influence metastatic progression through manipulation of the TME.
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    Engineering the pre-metastatic niche
    (Nature Portfolio, 2017) Aguado, Brian A.; Bushnell, Grace G.; Rao, Shreyas S.; Jeruss, Jacqueline S.; Shea, Lonnie D.; Northwestern University; University of Michigan; University of Alabama Tuscaloosa
    The pre-metastatic niche -the accumulation of aberrant immune cells and extracellular-matrix proteins in target organs primes the initially healthy organ microenvironment and renders it amenable for subsequent colonization by metastatic cancer cells. By attracting metastatic cells, mimics of the pre-metastatic niche offer both diagnostic and therapeutic potential. However, deconstructing the complexity of the niche by identifying the interactions between cell populations as well as the mediatory roles of the immune system, soluble factors, extracellular-matrix proteins and stromal cells has proved challenging. Experimental models are needed to recapitulate niche-population biology in situ and to mediate in vivo tumour-cell homing, colonization and proliferation. In this Review, we outline the biology of the pre-metastatic niche and discuss advances in the engineering of niche-mimicking biomaterials that regulate the behaviour of tumour cells at an implant site. Such 'oncomaterials' offer strategies for the early detection of metastatic events, the inhibition of the formation of the pre-metastatic niche and the attenuation of metastatic progression.
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    Enhanced Survival with Implantable Scaffolds That Capture Metastatic Breast Cancer Cells In Vivo
    (American Association of Cancer Research, 2016) Rao, Shreyas S.; Bushnell, Grace G.; Azarin, Samira M.; Spicer, Graham; Aguado, Brian A.; Stoehr, Jenna R.; Jiang, Eric J.; Backman, Vadim; Shea, Lonnie D.; Jeruss, Jacqueline S.; University of Alabama Tuscaloosa; University of Michigan; University of Minnesota Twin Cities; Northwestern University; University of Colorado Boulder
    The onset of distant organ metastasis from primary breast cancer marks the transition to a stage IV diagnosis. Standard imaging modalities often detect distant metastasis when the burden of disease is high, underscoring the need for improved methods of detection to allow for interventions that would impede disease progression. Here, microporous poly(e-caprolactone) scaffolds were developed that capture early metastatic cells and thus serve as a sentinel for early detection. These scaffolds were used to characterize the dynamic immune response to the implant spanning the acute and chronic foreign body response. The immune cell composition had stabilized at the scaffold after approximately 1 month and changed dramatically within days to weeks after tumor inoculation, with CD11b(+)Gr1(hi)Ly6C(-) cells having the greatest increase in abundance. Implanted scaffolds recruited metastatic cancer cells that were inoculated into the mammary fat pad in vivo, which also significantly reduced tumor burden in the liver and brain. Additionally, cancer cells could be detected using a label-free imaging modality termed inverse spectroscopic optical coherence tomography, and we tested the hypothesis that subsequent removal of the primary tumor after early detection would enhance survival. Surgical removal of the primary tumor following cancer cell detection in the scaffold significantly improved disease-specific survival. The enhanced disease-specific survival was associated with a systemic reduction in the CD11b(+)Gr1(hi)Ly6C(-) cells as a consequence of the implant, which was further supported by Gr-1 depletion studies. Implementation of the scaffold may provide diagnostic and therapeutic options for cancer patients in both the high-risk and adjuvant treatment settings. (C) 2016 AACR.
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    Extracellular matrix mediators of metastatic cell colonization characterized using scaffold mimics of the pre-metastatic niche
    (Elsevier, 2016) Aguado, Brian A.; Gaffe, Jordan R.; Nanavati, Dhaval; Rao, Shreyas S.; Bushnell, Grace G.; Azarin, Samira M.; Shea, Lonnie D.; Northwestern University; University of Alabama Tuscaloosa; University of Michigan; University of Minnesota Twin Cities
    Metastatic tumor cells colonize the pre-metastatic niche, which is a complex microenvironment consisting partially of extracellular matrix (ECM) proteins. We sought to identify and validate novel contributors to tumor cell colonization using ECM-coated poly(epsilon-caprolactone) (PCL) scaffolds as mimics of the pre metastatic niche. Utilizing orthotopic breast cancer mouse models, fibronectin and collagen IV-coated scaffolds implanted in the subcutaneous space captured colonizing tumor cells, showing a greater than 2-fold increase in tumor cell accumulation at the implant site compared to uncoated scaffolds. As a strategy to identify additional ECM colonization contributors, decellularized matrix (DCM) from lungs and livers containing metastatic tumors were characterized. In vitro, metastatic cell adhesion was increased on DCM coatings from diseased organs relative to healthy DCM. Furthermore, in vivo implantations of diseased DCM-coated scaffolds had increased tumor cell colonization relative to healthy DCM coatings. Mass-spectrometry proteomics was performed on healthy and diseased DCM to identify candidates associated with colonization. Myeloperoxidase was identified as abundantly present in diseased organs and validated as a contributor to colonization using myeloperoxidase-coated scaffold implants. This work identified novel ECM proteins associated with colonization using decellularization and proteomics techniques and validated candidates using a scaffold to mimic the pre-metastatic niche. Statement of Significance The pre-metastatic niche consists partially of ECM proteins that promote metastatic cell colonization to a target organ. We present a biomaterials-based approach to mimic this niche and identify ECM mediators of colonization. Using murine breast cancer models, we implanted microporous PCL scaffolds to recruit colonizing tumor cells in vivo. As a strategy to modulate colonization, we coated scaffolds with various ECM proteins, including decellularized lung and liver matrix from tumor-bearing mice. After characterizing the organ matrices using proteomics, myeloperoxidase was identified as an ECM protein contributing to colonization and validated using our scaffold. Our scaffold provides a platform to identify novel contributors to colonization and allows for the capture of colonizing tumor cells for a variety of downstream clinical applications. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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    High Frequency Spectral Ultrasound Imaging to Detect Metastasis in Implanted Biomaterial Scaffolds
    (Springer, 2020) Bushnell, Grace G.; Hong, Xiaowei; Hartfield, Rachel M.; Zhang, Yining; Oakes, Robert S.; Rao, Shreyas S.; Jeruss, Jacqueline S.; Stegemann, Jan P.; Deng, Cheri X.; Shea, Lonnie D.; University of Michigan; University of Alabama Tuscaloosa
    For most cancers, metastasis is the point at which disease is no longer curable. Earlier detection of metastasis, when it is undetectable by current clinical methods, may enable better outcomes. We have developed a biomaterial implant that recruits metastatic cancer cells in mouse models of breast cancer. Here, we investigate spectral ultrasound imaging (SUSI) as a non-invasive strategy for detecting metastasis to the implanted biomaterial scaffolds. Our results show that SUSI, which detects parameters related to tissue composition and structure, identified changes at an early time point when tumor cells were recruited to scaffolds in orthotopic breast cancer mouse models. These changes were not associated with acellular components in the scaffolds but were reflected in the cellular composition in the scaffold microenvironment, including an increase in CD31 + CD45- endothelial cell number in tumor bearing mice. In addition, we built a classification model based on changes in SUSI parameters from scaffold measurements to stratify tumor free and tumor bearing status. Combination of a linear discriminant analysis and bagged decision trees model resulted in an area under the curve of 0.92 for receiver operating characteristics analysis. With the potential for early non-invasive detection, SUSI could facilitate clinical translation of the scaffolds for monitoring metastatic disease.
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    Microporous scaffolds loaded with immunomodulatory lentivirus to study the contribution of immune cell populations to tumor cell recruitment in vivo
    (Wiley, 2020) Bushnell, Grace G.; Rao, Shreyas S.; Hartfield, Rachel M.; Zhang, Yining; Oakes, Robert S.; Jeruss, Jacqueline S.; Shea, Lonnie D.; University of Michigan; University of Alabama Tuscaloosa
    Metastases are preceded by stochastic formation of a hospitable microenvironment known as the premetastatic niche, which has been difficult to study. Herein, we employ implantable polycaprolactone scaffolds as an engineered premetastatic niche to independently investigate the role of interleukin-10 (IL10), CXCL12, and CCL2 in recruiting immune and tumor cells and impacting breast cancer cell phenotype via lentiviral overexpression. Lentivirus delivered from scaffolds in vivo achieved sustained transgene expression for 56 days. IL10 lentiviral expression, but not CXCL12 or CCL2, significantly decreased tumor cell recruitment to scaffolds in vivo. Delivery of CXCL12 enhanced CD45+ immune cell recruitment to scaffolds while delivery of IL10 reduced immune cell recruitment. CCL2 did not alter immune cell recruitment. Tumor cell phenotype was investigated using conditioned media from immunomodulated scaffolds, with CXCL12 microenvironments reducing proliferation, and IL10 microenvironments enhancing proliferation. Migration was enhanced with CCL2 and reduced with IL10-driven microenvironments. Multiple linear regression identified populations of immune cells associated with tumor cell abundance. CD45+ immune and CD8+ T cells were associated with reduced tumor cell abundance, while CD11b+Gr1+ neutrophils and CD4+ T cells were associated with enhanced tumor cell abundance. Collectively, biomaterial scaffolds provide a tool to probe the formation and function of the premetastatic niche.
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    Secretome identification of immune cell factors mediating metastatic cell homing
    (Nature Portfolio, 2015) Aguado, Brian A.; Wu, Jia J.; Azarin, Samira M.; Nanavati, Dhaval; Rao, Shreyas S.; Bushnell, Grace G.; Medicherla, Chaitanya B.; Shea, Lonnie D.; Northwestern University; University of Minnesota Twin Cities; University of Alabama Tuscaloosa; University of Michigan; Feinberg School of Medicine
    Metastatic cell homing is a complex process mediated in part by diffusible factors secreted from immune cells found at a pre-metastatic niche. We report on connecting secretomics and TRanscriptional Activity CEll aRray (TRACER) data to identify functional paracrine interactions between immune cells and metastatic cells as novel mediators of homing. Metastatic breast cancer mouse models were used to generate a diseased splenocyte conditioned media (D-SCM) containing immune cell secreted factors. MDA-MB-231 metastatic cell activity including cell invasion, migration, transendothelial migration, and proliferation were increased in D-SCM relative to control media. Our D-SCM secretome analysis yielded 144 secreted factor candidates that contribute to increased metastatic cell activity. The functional mediators of homing were identified using MetaCore software to determine interactions between the immune cell secretome and the TRACER-identified active transcription factors within metastatic cells. Among the 5 candidate homing factors identified, haptoglobin was selected and validated in vitro and in vivo as a key mediator of homing. Our studies demonstrate a novel systems biology approach to identify functional signaling factors associated with a cellular phenotype, which provides an enabling tool that complements large-scale protein identification provided by proteomics.