Browsing by Author "Martinez, Mariane"

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    Hydrogel-Based 3D Model of Patient-Derived Prostate Xenograft Tumors Suitable for Drug Screening
    (American Chemical Society, 2014) Fong, Eliza L.S.; Martinez, Mariane; Yang, Jun; Mikos, Antonios G.; Navone, Nora M.; Harrington, Daniel Anton; Farach-Carson, Mary C.
    The lack of effective therapies for bone metastatic prostate cancer (PCa) underscores the need for accurate models of the disease to enable the discovery of new therapeutic targets and to test drug sensitivities of individual tumors. To this end, the patient-derived xenograft (PDX) PCa model using immunocompromised mice was established to model the disease with greater fidelity than is possible with currently employed cell lines grown on tissue culture plastic. However, poorly adherent PDX tumor cells exhibit low viability in standard culture, making it difficult to manipulate these cells for subsequent controlled mechanistic studies. To overcome this challenge, we encapsulated PDX tumor cells within a three-dimensional hyaluronan-based hydrogel and demonstrated that the hydrogel maintains PDX cell viability with continued native androgen receptor expression. Furthermore, a differential sensitivity to docetaxel, a chemotherapeutic drug, was observed as compared to a traditional PCa cell line. These findings underscore the potential impact of this novel 3D PDX PCa model as a diagnostic platform for rapid drug evaluation and ultimately push personalized medicine toward clinical reality.
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    Role of cell-extracellular matrix interactions on tissue morphology, cell phenotype and organization in a salivary gland regeneration model
    (2019-04-17) Martinez, Mariane; Harrington, Daniel A
    Head and neck cancer affects over 64,000 Americans every year. Most of these patients receive radiation therapy as part of their standard treatment, which leads to irradiation-induced xerostomia (dry mouth). Xerostomia drastically impairs these patients’ quality of life. Our lab proposes to develop a functional gland, suitable for re-implantation, from salivary-derived human stem/progenitor cells (hS/PCs) isolated from the patient before radiation therapy. Biocompatible hyaluronic acid (HA)-based hydrogels, functionalized with extracellular matrix (ECM)-derived peptides and seeded with hS/PCs and other support cells, will be used as a scaffold for bioengineering an autologous salivary gland replacement. The first part of this work showed that hydrogel porosity and peptide content impacted hS/PC viability and 3D organization. Peptide-modified hydrogels maintained high hS/PC viability and yielded larger multicellular structures that better resembled a developing salivary gland. Use of an integrin ligand led to a higher number of multicellular structures and enhanced hS/PC proliferation. Specifically, migration-permissive (MP-HA) hydrogels led to the highest activation of integrin β1. In short, these experiments defined a hydrogel parameter space for hS/PC encapsulation and 3D culture that avoids confined, spheroidal multicellular assemblies in favor of asymmetric structures with early peripheral buds. Such features bring the models closer to the observed behavior of branching epithelial buds during salivary morphogenesis. The second part of this work describes the isolation and characterization of human salivary-derived fibroblasts (hSFs), and their implementation in co-culture with hS/PCs. hSF-hS/PC 3D encapsulations were conducted either as fully mixed co-cultures, or as adjacent but discrete bilayers. Mixed co-cultures led to significantly higher overall cell viability and structure formation than discrete bilayer co-cultures and monocultures of either cell types. hSFs expressed basement membrane proteins in mixed co-cultures; basement membrane accumulated most in between single hSFs and multicellular hS/PC structures. Lastly, time-lapse imaging of mixed co-cultures illustrated that single cells and multicellular structures composed of either or both cell types were dynamically migrating and reorganizing in MP-HA over time. Thus, the use of MP-HA and a mesenchymal cell type enhanced overall cell viability, growth, and organization in a salivary gland regeneration model.
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    Three-dimensional (3D) culture of bone-derived human 786-O renal cell carcinoma retains relevant clinical characteristics of bone metastases
    (Elsevier, 2015) Pan, Tianhong; Fong, Eliza L.S.; Martinez, Mariane; Harrington, Daniel Anton; Lin, Sue-Hwa; Farach-Carson, Mary C.; Satcher, Robert L.
    Bone metastases from renal cell carcinoma (RCC) are typically lytic, destructive, and resistant to treatment regimens. Current in vitro models for studying metastasis introduce artifacts that limit their usefulness. Many features of tumors growing in bone are lost when human RCC cells are cultured in two-dimensional (2D) plastic substrata. In this study, we established that RCC spheroids, consisting of aggregates of cells, can be grown in a three-dimensional (3D) hyaluronate hydrogel-based culture system. The bone-derived human 786-O RCC subline proliferated and survived long term in these hydrogels. Additionally, RCC spheroids in 3D hydrogels demonstrated lower proliferation rates than their counterparts grown in 2D. Overall, gene expression patterns of RCC spheroids in 3D more closely mimicked those observed in vivo than did those of cells grown in 2D. Of particular importance, selected adhesion molecules, angiogenesis factors, and osteolytic factors that have been shown to be involved in RCC bone metastasis were found to be expressed at higher levels in 3D than in 2D cultures. We propose that the 3D culture system provides an improved platform for RCC bone metastasis studies compared with 2D systems.