Abstract LB-269: Engineering a vascularized 3D in vitro model of cancer progression

Abstract

Abstract Microenvironmental cues regulate the neo-vascularisation and angiogenic processes within a tumour. The hallmark of cancer is the ability of cancer cells to disseminate and invade to distant sites. The presence of a ‘leaky’ vasculature in the tumour microenvironment facilitates this migration of cancer cells. Using tissue-engineering strategies, we have developed a 3D in vitro cancer model (tumouroid), where we have engineered specific compartments for both the cancer mass and the surrounding stroma. We have utilized a biomimetic matrix for the cancer mass the stroma engineered of collagen I and laminin, and used plastic compression to increase the cell and matrix density by removal of interstitial fluid in collagen hydrogels. We created artificial cancer masses (ACMs) containing colorectal cancer cells (HT29 and HCT116) and nested them within collagen/laminin stromal surrounds (SS) (both ∼10% w/v collagen) containing human dermal fibroblasts (HDFs) and endothelial cells (HUVECs). We have delineated cell specific mechanisms to describe changes in the invasion pattern of cancer cells dependent upon the stromal composition and density. HT29 cells invaded as spherical aggregates of cells while HCT116 cells invaded as contiguous cell sheets. Multicellular cultures were maintained for up to 21 days and endothelial cell morphology was investigated using immunofluorescence of CD31. In HDF-HUVEC co-cultures, HUVECs formed highly branched (29.25 ± 3.86 branches) end-to-end networks with an average length and width of 197.4μm ± 87.5μm and 19μm ± 8.1μm respectively. In the presence of HT29 cancer cells, HUVEC network formation was considerably altered with HUVECs forming much longer and wider networks (456.8μm ± 136μm and 24.2μm ± 7μm) but significantly less interconnected (13.5 ± 5.1 branches). The loss of CK20 expression by the invading cancer epithelial cell sheet was also confirmed by immunofluorescence. The loss of CK20 expression has been known to correspond with high levels of microsatellite instability and overall poor prognosis1. These findings signify the importance of a biomimetic environment in which to culture cancer cells, to mimic the native physiological response of these cells. The tumouroid model is an important tool to study the effect of microenvironmental conditions on tumor malignancy in vitro and in vivo. 1. Kim, J. H., Rhee, Y., Bae, J. M., Cho, N. & Kang, G. H. Loss of CDX2/CK20 expression is associated with poorly differentiated carcinoma, the CpG island methylator phenotype, and adverse prognosis in microsatellite-unstable colorectal cancer. Am. J. Surg. Pathol. 37, 1532-41 (2013). Citation Format: Tarig Magdeldin, Mark Emberton, Marilena Loizidou, Umber Cheema. Engineering a vascularized 3D in vitro model of cancer progression. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-269.