Blocking SCF/c-Kit signal did not inhibit the proliferation of cultured liver progenitor cells

Oval cells are the putative liver stem cells that proliferate during hepatocarcinogenesis and chemically-induced severe liver injury. Antigens traditionally associated with haematopoietic cells, such as c-Kit, have been reported to be expressed by oval cells. Previous studies suggested that stem cell factor (SCF) and c-Kit were critical to oval cell development. However, the role of SCF/c-Kit signals in oval cell proliferation still remains unclear. Recently, we reported the establishment of oval cell-derived liver epithelial progenitor cells (LEPCs). In this work, we showed LEPCs co-expressed c-Kit and its ligand SCF. The involvement of SCF/c-Kit signals in LEPCs proliferation was investigated either by exposing LEPCs to c-Kit inhibitors (STI571 and AG1296), SCF, anti-SCF neutralized antibody or by using small interfering RNA to knock-down c-Kit expression. Our data demonstrate that blocking SCF/c-Kit signal did not inhibit the proliferation of LEPCs, which suggest SCF/c-Kit is not necessary for the proliferation of oval cells, at least for the cultured oval cell counterpart LEPCs.