Impact of the physical cellular microenvironment on the structure and function of a hepatocytes for drug toxicity applications
It is widely recognised that cells respond to their microenvironment, which has particular implications for in vitro cell culture practices. Namely, growth cues provided by traditional 2D cell culture substrates are far removed from the native 3D structure of in vivo tissues. Culture geometry is one of many factors that differs between in vitro culture and in vivo cellular environments. This results in in vitro studies being so far removed from their native counterpart, that they lose some of their predictive capability and reliability. In this study we examine the cellular processes that occur when a cell is cultured on 2D or 3D surfaces for a short period of 8 days prior to use in functional assays, which we term: priming. We follow the process of mechanotransduction from cytoskeletal alterations, to changes to nuclear structure leading to alterations in gene expression. These changes in gene expression ultimately resulting in enhanced expression of functional proteins and improved functional capabilities. In this study, we use hepatocytes (HepG2 cells) as a model cell line, due to their commonplace use and robustness for drug toxicity screening. We demonstrate enhanced functionality and improved drug toxicity profiles that better reflect the clinical response in vivo. However, we expect these findings more broadly reflect in vitro cell culture practises across all areas of cell biology, demonstrating the fundamental impact of mechanotransduction in bioengineering, cell biology and in vitro assays. Overall design: HepG2 (hepatocellular carcinoma) cells were grown for 8 days either on conventional 2D cell culture ware, or on a 3D topography using a porous, biologically inert polystyrene membrane. There are four replicates in each treatment.