Cells grown in three-dimensional spheroids mirror in vivo metabolic response of epithelial cells.

Metabolism in cells adapts quickly to changes in nutrient availability and cellular differentiation status, including growth conditions in cell culture settings. The last decade saw a vast increase in three-dimensional (3D) cell culture techniques, engendering spheroids and organoids. These methods were established to improve comparability to in vivo situations, differentiation processes and growth modalities. How far spheroids mimic in vivo metabolism, however, remains enigmatic. Here, to our knowledge, we compare for the first time metabolic fingerprints between cells grown as a single layer or as spheroids with freshly isolated in situ tissue. While conventionally grown cells express elevated levels of glycolysis intermediates, amino acids and lipids, these levels were significantly lower in spheroids and freshly isolated primary tissues. Furthermore, spheroids differentiate and start to produce metabolites typical for their tissue of origin. 3D grown cells bear many metabolic similarities to the original tissue, recommending animal testing to be replaced by 3D culture techniques. To investigate how far 3D cell culture techniques like spheroids mimic in vivo metabolism, Lagies et al. compare renal cell lines growing in conventional 2D culture and 3D spheroids with cells freshly isolated from murine kidney tissue. 3D grown cells bear many metabolic similarities to the original tissue, different from conventional 2D cell culture.