The role of FAK-ERK signal transduction pathway in apoptosis of hepatic stellate cell / 中华肝脏病杂志

ABSTRACT

<p><b>OBJECTIVES</b>To investigate the effects of FAK-related non-kinase (FRNK) on the apoptosis of hepatic stellate cells (HSC) in vitro and on the extracellular signal-regulated kinase (ERK) signal transduction pathway.</p><p><b>METHODS</b>HSC were stimulated by fibronectin (FN), and then they were transfected with FAK-related non-kinase (FRNK) plasmids mediated by cationic liposome. The apoptosis of FRNK-induced HSC was examined by annexin-V/propidium iodide double-labeled flow cytometry (FCM), gel electrophoresis and transmission electron microscopy. Levels of FRNK, FAK, p-FAK (Tyr397), ERK1 and p-ERK in HSC were assayed by Western blot on the protein level, and by RT-PCR on the mRNA level.</p><p><b>RESULTS</b>The expression of FRNK was enhanced after FRNK plasmids were transiently transfected into the HSC. The apoptotic rate of the HSC exposed to FRNK plasmids for 48 h was higher than that in the non-FRNK plasmid group (25.37%+/-1.92% vs 9.28%+/-1.05%, P less than 0.01), and was accompanied by a significantly higher activity of caspase-3 both in the protein and in the mRNA levels [(264.17+/-12.60 vs 185.82+/-9.69), P less than 0.01; (4.19+/-0.48 vs 1.07+/-0.27), P less than 0.01]. After exposure of HSC to FRNK plasmids, compared with the non-FRNK plasmid group, the expressions of p-FAK, ERK1 and p-ERK in protein and mRNA levels were lower; on the contrary, compared with the control group, the expressions of p-FAK, ERK1 and p-ERK in the FN group were higher.</p><p><b>CONCLUSION</b>The expression of FRNK was enhanced and the phosphorylation of FAK was inhibited after FRNK was transiently transfected into HSC in vitro. FRNK induces apoptosis of HSC. FAK-ERK signal transduction pathway perhaps is involved in the process.</p>