Engineering fibrotic tissue in pancreatic cancer: a novel three-dimensional model to investigate nanoparticle delivery.
ABSTRACT Pancreatic cancer contains both fibrotic tissue and tumor cells with embedded vasculature. Therefore anti-cancer nanoparticles need to extravasate from tumor vasculature and permeate thick fibrotic tissue to target tumor cells. To date, permeation of drugs has been investigated in vitro using monolayer models. Since three-dimensional migration of nanoparticles cannot be analyzed in a monolayer model, we established a novel, three-dimensional, multilayered, in vitro model of tumor fibrotic tissue, using our hierarchical cell manipulation technique with K643f fibroblasts derived from a murine pancreatic tumor model. NIH3T3 normal fibroblasts were used in comparison. We analyzed the size-dependent effect of nanoparticles on permeation in this experimental model using fluorescent dextran molecules of different molecular weights. The system revealed permeation decreased as number of layers of cultured cells increased, or as molecule size increased. Furthermore, we showed changes in permeation depended on the source of the fibroblasts. Observations of this sort cannot be made in conventional monolayer culture systems. Thus our novel technique provides a promising in vitro means to investigate permeation of nanoparticles in fibrotic tissue, when both type and number of fibroblasts can be regulated.
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ABSTRACT: Common methods to characterize treatment efficacy based on morphological imaging may misrepresent outcomes and exclude effective therapies. Using a three-dimensional model of ovarian cancer, two functional treatment response metrics are used to evaluate photodynamic therapy (PDT) efficacy: total volume, calculated from viable and nonviable cells, and live volume, calculated from viable cells. The utility of these volume-based metrics is corroborated using independent reporters of photodynamic activity: viability, a common fluorescence-based ratiometric analysis, and photosensitizer photobleaching, which is characterized by a loss of fluorescence due in part to the production of reactive species during PDT. Live volume correlated with both photobleaching and viability, suggesting that it was a better reporter of PDT efficacy than total volume, which did not correlate with either metric. Based on these findings, live volume and viability are used to probe the susceptibilities of tumor populations to a range of PDT dose parameters administered using 0.25, 1, and 10 μM benzoporphyrin derivative (BPD). PDT with 0.25 μM BPD produces the most significant reduction in live volume and viability and mediates a substantial shift toward small nodules. Increasingly sophisticated bioengineered models may complement current treatment planning approaches and provide unique opportunities to critically evaluate key parameters including metrics of therapeutic response.Journal of Biomedical Optics 09/2013; 18(9):98004. · 2.75 Impact Factor
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ABSTRACT: Three-dimensional (3D) hepatocyte cultures have attracted much attention to obtain high biological functions of hepatocyte for pharmaceutical drug assessment. However, maintaining the high functions for over one month is still a key challenge although many approaches have been reported. In this study, we demonstrate for the first time simple and rapid construction of 3D-hepatocyte constructs by our cell accumulation technique and their high biological functions for one month, without any medium change. The human hepatocyte carcinoma (HepG2) cells were coated with approximately 7 nm-sized extracellular matrix (ECM) films consisting of fibronectin (FN) and gelatin (G), and then incubated in cell culture insert to construct 3D-tissue constructs for 24 hours. The thickness of obtained 3D-HepG2 constructs was easily controlled by altering seeding cell number and the maximum is over 100 μm. When a large volume of culture media was employed, the 3D-constructs showed higher mRNA expression of albumin and some cytochrome P450 (CYP) enzymes as compared to general two-dimensional (2D) culture. Surprisingly, their high cell viabilities (over 80%) and high mRNA expressions were successfully maintained without medium change for at least 27 days. These results demonstrate novel easy and rapid technique to construct 3D-human liver tissue models which can maintain their high functions and viability for 1 month without medium change.Journal of Biomedical Materials Research Part A 08/2014; · 2.83 Impact Factor
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ABSTRACT: Three-dimensional (3D) tissue constructs consisting of human cells have opened a new avenue for tissue engineering, pharmaceutical and pathophysiological applications, and have great potential to estimate the dynamic pharmacological effects of drug candidates, metastasis processes of cancer cells, and toxicity expression of nano-materials, as a 3D-human tissue model instead of in vivo animal experiments. However, most 3D-cellular constructs are a cell spheroid, which is a heterogeneous aggregation, and thus the reconstruction of the delicate and precise 3D-location of multiple types of cells is almost impossible. In recent years, various novel technologies to develop complex 3D-human tissues including blood and lymph capillary networks have demonstrated that physiological human tissue responses can be replicated in the nano/micro-meter ranges. Here, we provide a brief overview on current 3D-tissue fabrication technologies and their biomedical applications. 3D-human tissue models will be a powerful technique for pathophysiological applications.Advanced drug delivery reviews 01/2014; · 11.96 Impact Factor