ABSTRACT
Objective To construct short hairpin RNA (shRNA) expression plasmids against the inhibitor of differentiation 2 (Id2) gene and establish a suitable cell model for the role of Id2 in proliferation and differentiation of human Ewing sarcoma cell.Methods Three shRNA sequences targeting Id2 gene were designed and inserted into the pGPU6/GFP/Neo (-shRNA-Id2) expression vectors.The recombinant pGPU6/GFP/Neo-shRNA-Id2 plasmids were introduced into Ewing sarcoma RD-ES cells by liposome-mediated transfection.The knock-down efficiency of Id2 in infected RD-ES cells was verified by Western blot assay.The cell growth and cell cycle changes were evaluated by cell counting and flow cytometry between transfected cells and control cells.Results The Id2 expression decreased 54 ％ and 57 ％,respectively,in RD-ES cell line which were transfected with the shRNA-Id2-543 and shRNA-Id2-593 plasmids compared with the control group cells by Western blot analysis.The cell growth assay demonstrated that the cell number in transfected cells was significantly decreased during 6-7 d compared with the control group (P ＜ 0.05).The cells at the S-phase of cell cycle were increased [(36.60±1.53) ％ and (44.89E2.46) ％ vs (29.73±2.03) ％,P ＜ 0.05],and no significant changes at the G2 phase or even reduction in the transfected cells.Conclusions Id2 stable knock-down cell lines are successfully established.The reduced expression of Id2 is related with decreased cell growth and cell cycle arrest in the S-phase.Id2 maybe plays an important role in proliferation of Ewing sarcoma cell.