211 Background: Importance of interaction between cancer and stromal cells has been widely recognized in tumor progression and tolerance against treatment. Although 2D culture and spheroid consisting only cancer cells still remains the preferred platform for most laboratory preclinical studies while these provide only limited information about tumor microenvironment. In order to mimic the patient tumor tissue, ex vivo model which recaptures the tumor microenvironment is required. Methods: Layered 3D stromal tissues comprising microvascular network were produced by culturing fibroblasts and endothelial cells coated with the extra-cellular matrix (ECM) and natural polysaccharide, namely collagen and heparin. The layered 3D stromal tissues and co-cultured tumor were morphologically evaluated by HE stain, immunohistochemistry and immunofluorescence (IF). Their gene expression and secretome profile were characterized by RNA-sequencing and bio-plex suspension array technologies. Furthermore, drug sensitivity assay were conducted using popular colorectal cancer cell lines, and patient-derived cell lines (PDCs) established in the laboratory of JFCR. Remaining cancer cells post drug treatment were quantified by IF and imaging analysis. Results: The 3D stromal tissues including CD31 positive luminal structure were multi-layered (approximately 20 layers), and the tendency that dense microvascular network was formed nearby cancer cells was observed. In comparison with 2D culture or 3D mono-cultured spheroid model, decreased drug sensitivities were represented in the layered 3D co-cultured model. Omics profiles difference among models suggest that our 3D model has some similarity to in vivo tumor. Conclusions: We developed the layered 3D stromal tissue culture system including blood micro-vessels. Drug sensitivity in the co-cultured tumors may reflect the response of cancer cells in in vivo. Our unique 3D ex vivo model appear to be a valuable tool for drug evaluation, and thus testing approved and/or developing compounds with patient-derived cells would enable better prediction their efficacy.
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