Over-expression of Raf kinase inhibitor protein (RKIP) inhibits the proliferation of LX-2 human hepatic stellate cells

Objective To investigate the effect of Raf kinase inhibitor protein (RKIP) over-expression on the proliferation of LX-2 human hepatic stellate cells. Methods Recombinant plasmid pcDNA3.1-RKIP was transfected into LX-2 cells. G418 was used to screen and culture stably infected cells. MTT assay and colony formation assay were used to examine the effect of RKIP over-expression on cell proliferation and colony formation, respectively. Western blotting was performed to assess the expressions of RKIP, α-smooth muscle actin (α-SMA), type 1 collagen (Col1) and matrix metalloproteinase 1(MMP-1) and MMP-2 as well as extracellular signal-regulated kinases/mitogen-activated protein kinase (ERK/MAPK) signaling pathway-related proteins. Results Compared with the control cells, RKIP over-expression significantly inhibited LX-2 cell proliferation and colony formation, and reduced the protein expressions of Col1, α-SMA, MMP-1 and MMP-2. Moreover, RKIP over-expression remarkably inhibited the phosphorylation of ERK/MAPK. Conclusion Over-expressed RKIP inhibits LX-2 cell proliferation and the mechanism is related to the inhibition of ERK/MAPK signaling pathway.