OBJECTIVEHepatic stellate cells (HSC) in hepatocellular carcinoma (HCC) transdifferentiate into extracellular matrix-producing myofibroblasts. Activated HSC can promote invasion and metastasis of HCC. To understand the differences of HSC in normal liver and HCC, we compared the gene expression patterns in HCC cell induction-activated and culture-activated rat HSC.

METHODSHSC were isolated by density centrifugation and exposed to conditioned medium from rat HCC cell line C5F. Expression of 22 012 genes in quiescent HSC, culture-activated HSC and HCC induction-activated HSC was analyzed by cDNA microarray and confirmed by real-time RT-PCR and Western blot.

RESULTS1672 genes were differentially expressed in culture-activated HSC, including proinflammatory factors, cell adhesion molecules, cell surface receptors, signaling transduction molecules and immune factors. 711 genes were differentially expressed in HCC induction-activated HSC. Some of them were identical to those in culture-activated HSC. HCC Induction-activated HSC showed specific gene expression patterns, including Raf1, Rac2, Adam17, Wnt6, MMP-9 and TNF, suggesting that HCC cells can specifically induce HSC activation.

CONCLUSIONThe gene expression patterns in HCC induction-activated HSC are different from those in culture-activated HSC. HCC induction-activated HSC may play a major role in the invasion and metastasis of HCC. In vivo activation should be considered as the standard for the study of HSC biology. HCC induction-activated HSC should be considered as the standard for HSC biology studies.