Semi-Automated Phenotypic Analysis of Functional 3D Spheroid Cell Cultures.

We present a protocol that describes the properties and advantages of using a standalone clinostat incubator for growing, treating, and monitoring 3D cell cultures. The clinostat mimics an environment where cells can assemble as highly reproducible spheroids with low shear forces and active nutrient diffusion. We demonstrate that both cancer and non-cancer hepatocytes (HepG2/C3A and THLE-3 cell lines) require 3 weeks of growth prior to achieving functionalities comparable to liver cells. This protocol highlights the convenience of utilizing incubators for 3D cells with cameras monitoring the cell growth, as snapshots can be taken to count and measure spheroids upon treatment. We describe the comparison of THLE-3 and HepG2/C3A cell lines, showing how non-cancerous cell lines can be grown as well as immortalized cancer cells. We demonstrate and illustrate how proteomics experiments can be conducted from a few spheroids, which can be collected without perturbing cell signaling, i.e., no trypsinization required. We show that proteomics analysis can be used to monitor the typical liver phenotype of respiratory chain metabolism and the production of proteins involved in metal detoxification and describe a semi-automated system to count and measure the spheroid's area. Altogether, the protocol presents a toolbox that comprises a phenotypic characterization via image capture and a proteomics pipeline to experiment on 3D cell culture models.

Mapping Proteome and Lipidome Changes in Early-Onset Non-Alcoholic Fatty Liver Disease Using Hepatic 3D Spheroids.

Non-alcoholic fatty liver disease affects one-fourth of the world's population. Central to the disease progression is lipid accumulation in the liver, followed by inflammation, fibrosis and cirrhosis. The underlying mechanism behind the early stages of the disease is poorly understood. We have exposed human hepatic HepG2/C3A cells-based spheroids to 65 µM oleic acid and 45 µM palmitic acid and employed proteomics and lipidomics analysis to investigate their effect on hepatocytes. The treatment successfully induced in vivo hallmarks of NAFLD, as evidenced by intracellular lipid accumulation and increased ATP levels. Quantitative lipidome analysis revealed an increase in ceramides, LPC and saturated triglycerides and a decrease in the ratio of PC/PE, similar to the changes observed in patients' liver biopsies. The proteomics analysis combined with qPCR showed increased epithelial to mesenchymal transition (EMT) signalling. Activation of EMT was further validated by transcriptomics in TGF-ß treated spheroids, where an increase in mesenchymal cell markers (N-cadherin and collagen expression) was found. Our study demonstrates that this model system thus closely echoes several of the clinical features of non-alcoholic fatty liver disease and can be used to investigate the underlying molecular changes occurring in the condition.

Clinostat 3D Cell Culture: Protocols for the Preparation and Functional Analysis of Highly Reproducible, Large, Uniform Spheroids and Organoids.

Growing cells as 3D structures need not be difficult. Often, it is not necessary to change cell type, additives or growth media used. All that needs to be changed is the geometry: cells (whether primary, induced pluripotent, transformed or immortal) simply have to be grown in conditions that promote cell-cell adhesion while allowing gas, nutrient, signal, and metabolite exchange. Downstream analysis can become more complicated because many assays (like phase contrast microscopy) cannot be used, but their replacements have been in use for many years. Most importantly, there is a huge gain in value in obtaining data that is more representative of the organism in vivo. It is the goal of the protocols presented here to make the transition to a new dimension as painless as possible. Grown optimally, most biopsy derived organoids will retain patient phenotypes, while cell (both stem cell, induced or otherwise or immortalized) derived organoids or spheroids will recover tissue functionality.

Method to Disassemble Spheroids into Core and Rim for Downstream Applications Such as Flow Cytometry, Comet Assay, Transcriptomics, Proteomics, and Lipidomics.

Cells cultured in a monolayer have been a central tool in molecular and cell biology, toxicology, biochemistry, and so on. Therefore, most methods for adherent cells in cell biology are tailored to this format of cell culturing. Limitations and disadvantages of monolayer cultures, however, have resulted in the ongoing development of advanced cell culturing techniques. One such technique is culturing cells as multicellular spheroids, that had been shown to mimic the physiological conditions found in vivo more accurately. This chapter presents a novel method for separation of the spheroid rim and core in mature spheroids (>21 days) for further analysis using advanced molecular biology techniques such as flow cytometry, viability estimations, comet assay, transcriptomics, proteomics and lipidomic. This fast and gentle disassembly of intact spheroids into rim and core fractions, and further into viable single-cell suspension provides an opportunity to bridge the gap from 3D cell culture to current state-of-the-art analysis methods.