Investigation of TGF‐α‐overexpressing mouse hepatocytes (TAMH) cultured as spheroids for use in hepatotoxicity screening of drug candidates

• Published in: Journal of applied toxicology 2024-02, Vol.44 (2), p.272-286
• Main Authors: Beirow, Kristin, Schmidt, Christian, Jürgen, Britta, Schlüter, Rabea, Schweder, Thomas, Bednarski, Patrick J.
• Format: Article
• Language: English
• Subjects: Acetaminophen; Animals; Cell culture; Chemical and Drug Induced Liver Injury - metabolism; Drug development; Electrons; Enzymes; flupirtine; Gene expression; Hepatocytes; Hepatocytes - metabolism; Hepatotoxicity; HepG2; Humans; Injury prevention; Liver; Liver - metabolism; Mice; Monolayers; retigabine; RT‐qPCR; Spheroids; Spheroids, Cellular; TAMH; Transforming Growth Factor alpha - metabolism; Transmission electron microscopy
• ISSN: 0260-437X; 1099-1263
• DOI: 10.1002/jat.4538

The immortalized mouse liver cell line TAMH has been described as a valuable tool for studying hepatotoxic mechanisms, but until now, it has only been reported to grow as a monolayer in culture. However, culturing hepatocytes as three‐dimensional (3D) spheroids has been shown to result in improved liver‐specific functions (e.g., metabolic capacity) by better mimicking the in vivo environment. This approach may lead to more reliable detection of drug‐induced liver injury (DILI) in the early phase of drug discovery, preventing post‐marketing drug withdrawals. Here, we investigated the cultivation of TAMH as 3D spheroids, characterizing them with optical and transmission electron microscopy as well as analyzing their gene expression at mRNA level (especially drug‐metabolizing enzymes) compared to TAMH monolayer. In addition, comparisons were made with spheroids grown from the human hepatoblastoma cell line HepG2, another current spheroid model. The results indicate that TAMH spheroids express hepatic structures and show elevated levels of some of the key phase I and II drug‐metabolizing enzymes, in contrast to TAMH monolayer. The in vitro hepatotoxic potencies of the drugs acetaminophen and flupirtine maleate were found to be very similar between TAMH spheroidal and the monolayer cultures. Both the advantages and disadvantages of TAMH spheroids as an in vitro hepatotoxicity model compared to monolayer model are discussed. 3D, or not 3D, that is the question! The TGF‐α‐overexpressing mouse hepatocyte cell line TAMH had been used as a monolayer (2D) in several studies to evaluate the hepatotoxicity of drugs in vitro. Here, we investigated whether TAMH cultured as three‐dimensional (3D) spheroids showed improved liver‐specific properties and could function as an in vitro model to study drug‐induced liver injury with comparison to other current spheroid models.