The importance of being a lumen

Advances in tissue engineering and microtechnology have enabled researchers to more easily generate in vitro tissue models that mimic the tissue geometry and spatial organization found in vivo ( e.g. , vessel or mammary duct models with tubular structures). However, the widespread adoption of these models for biological studies has been slow, in part due to the lack of direct comparisons between existing 2‐dimensional and 3‐dimensional cell culture models and new organotypic models that better replicate tissue structure. Using previously developed vessel and mammary duct models with 3‐dimensional lumen structures, we have begun to explore this question. In a direct comparison between these next generation organotypic models and more traditional methods, we observed differences in the levels of several secreted growth factors and cytokines. In addition, endothelial vessel geometry profoundly affects the phenotypic behavior of carcinoma cells, suggesting that more traditional in vitro assays may not capture in vivo events. Here, we seek to review and add to the increasing evidence supporting the hypothesis that using cell culture models with more relevant tissue structure influences cell fate and behavior, potentially increasing the relevance of biological findings.—Bischel, L. L., Sung, K. E., Jiménez‐Torres, J. A., Mader, B., Keely, P. J., Beebe, D. J., The importance of being a lumen. FASEB J. 28, 4583–4590 (2014). www.fasebj.org