[The role of FAK-ERK signal transduction pathway in apoptosis of hepatic stellate cell].
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Shen
Jian-gang
JG
Department of Gastroenterology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, China.
Zhang
Xiao-lan
XL
Huo
Xiao-xia
XX
D017209:Apoptosis; D002460:Cell Line; D049109:Cell Proliferation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D055166:Hepatic Stellate Cells / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction
D012333:RNA, Messenger; C113183:FAK-related nonkinase; D011505:Protein-Tyrosine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases