Genetic characteristics of the human hepatic stellate cell line LX–2

Based on their pivotal role in the initiation and progression of liver fibrogenesis, some major issues on fibrogenesis including the regulation of extracellular matrix (ECM) components, retinoid metabolism, and mechanisms of fibrogenic signalling are addressed in primary hepatic stellate cells (HSC) worldwide [1]. These cells execute a highly dynamic programme from quiescence to activation ending in a transdifferentiated phenotype termed myofibroblasts (MFB). Although the preparation of these primary cells is well established [2], the methodologies are time-consuming and most often require ethical and institutional approval by respective national and animal legislation committees, wasteful equipment and skilful assistants. To overcome these limitations, many investigators have transferred established concepts to develop permanent HSC cell lines [3]. The human HSC lines LX–1 and LX–2 were generated by either transformation with a plasmid encoding the SV40 large T antigen under the control of a Rous sarcoma virus promoter (LX–1) or by spontaneous immortalization of a subset of early LX–1 passages that were grown in low serum conditions (LX–2) [4]. Although this permanent line is used in many studies, a detailed genotypic characterisation of this cell line is still missing. Therefore, we performed an attempt to establish the karyotype of LX–2 cells by usage of different cytogenetic and molecular cytogenetic analyses techniques including chromosome multiprobe hybridisation and spectral karyotyping. We found that LX–2 cells encompass a complex karyotype with various numerical and structural abnormalities. However, despite the observed great genetic variability, we found a few cell line specific translocations that might be useful for cell line authentication and further might be of etiologic significance for the maintenance of an immortalized phenotype or in the control of other cellular features including partial serum independency.