Hepatoma cells are a promising cell source for the construction of bioartificial liver (BAL) systems owing to their high proliferative capability. However, their low liver function compared with primary hepatocytes is a major problem. In a previous study, we established a genetically modified hepatoma cell line, Hepa/8F5, in which eight liver-enriched transcription factor (LETF) genes were transduced into mouse hepatoma Hepa1-6 cells using a drug-inducible transactivator system. These cells proliferate actively under normal culture conditions, meaning that large quantities can be prepared easily. When the overexpression of the LETFs is induced by the addition of an inducer drug, cell growth stops and cell morphology changes with concomitant high expression of liver functions. However, the liver functions largely depend on the presence of the inducer drug, which must be continuously added to maintain these enhanced functions. In the present study, we attempted to modify the method of induction of LETF overexpression in Hepa/8F5 cells to remove the requirement for continual drug addition. To this end, we constructed a system in which the artificial transactivator was transcribed and amplified under the control of a heat-shock protein promoter, and introduced the system into the genome of Hepa/8F5 cells. In our modified cell line, heat-triggered LETF expression was confirmed to induce high liver function. After drug-screening of transfected cells, we established a hepatoma cell line (Hepa/HS), which exhibited high, heat-inducible liver functions. The Hepa/HS cells may represent a new cell source for hepatic studies such as the construction of BAL systems.

由于其高增殖能力，肝癌细胞是构建生物人工肝（BAL）系统的有前途的细胞来源。然而，与原代肝细胞相比，它们的低肝功能是一个主要问题。在之前的一项研究中，我们建立了一种转基因肝癌细胞系 Hepa/8F5，其中使用药物诱导的反式激活因子系统将八个富含肝脏的转录因子 (LETF) 基因转导到小鼠肝癌 Hepa1-6 细胞中。这些细胞在正常培养条件下活跃增殖，这意味着可以轻松制备大量细胞。当通过添加诱导剂药物诱导 LETF 的过表达时，细胞生长停止并且细胞形态发生变化，同时肝功能的高表达。然而，肝功能在很大程度上取决于诱导药物的存在，必须不断添加诱导药物以维持这些增强的功能。在本研究中，我们试图修改在 Hepa/8F5 细胞中诱导 LETF 过表达的方法，以消除持续添加药物的要求。为此，我们构建了一个系统，在该系统中，人工反式激活因子在热休克蛋白启动子的控制下进行转录和扩增，并将该系统引入到 Hepa/8F5 细胞的基因组中。在我们改良的细胞系中，证实热触发的 LETF 表达可诱导高肝功能。在对转染细胞进行药物筛选后，我们建立了肝癌细胞系 (Hepa/HS)，该细胞系表现出高热诱导肝功能。