Cancer medicine would benefit greatly from a practical technology that accurately predicts the sensitivity of individual patient tumors to drugs. Previously developed in vitro chemosensitivity models have generally failed to do this because they do not incorporate key aspects of the tumor microenvironment (TME), which clearly plays a role in drug resistance. There has been significant interest in patient-derived xenograft (PDX) chemosensitivity testing as an alternative to in vitro models, but the applicability of this approach is limited by engraftment percentages and growth rates.
We have developed an in vitro technology that is designed to recapitulate the 3D tissue architecture of patient-derived colorectal tumors including accessory (endothelial and immune) cells, starting with freshly excised tumor specimens. The system incorporates: 1) low-sheer, tangential flow of nutrient medium above and below an open, synthetic 3D cell scaffold; and 2) exchange of metabolic gasses via permeable membranes which separate the culture chamber core from gassing chambers located above and below the nutrient flow compartments. This design allows establishment of gas and nutrient gradients across the cell scaffold that closely mimic conditions in vivo.
Aliquots of mechanically and enzymatically dissociated, freshly excised, primary human colorectal adenocarcinomas were introduced into the 3D culture system and maintained for up to 3 weeks. Routine maintenance of the cultures involved partial medium exchanges as needed based on glucose concentrations in the circulating medium. The proportions and arrangement of key cell types (e.g., normal muscularis, tumor epithelium, stromal fibroblasts, endothelial cells, and immune cells) in the cultured explants were compared to those of the original tumor by standard histological techniques. Results revealed good agreement between the histology of the original tumor and that of the in vitro model. These results suggest that this model technology could be applied to individual patient drug selection as well as studies of colorectal cancer biology that are not feasible or practical in vivo.
Citation Format: William P. Pfund, Paul A. Neeb. A patient-derived in vitro model of colorectal cancer: a perfusion culture system that recapitulates patient tumor composition and structure in 3-dimensions. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-37. doi:10.1158/1538-7445.AM2014-LB-37