This study examined the effects of over-expression of leucine-rich repeats and immunoglobulin-like domains 3 (LRIG3) on the cell cycle and survival of human glioma cell line U87 and U251 and explored the possible mechanisms.The LRIG3 gene was transduced into U87 and U251 cells respectively by using lentivirus and the transduced cells were selected by puromycin.The changes in LRIG3 mRNA and protein levels were measured by RT-PCR and Western blotting.The apoptosis rate was detected by Annexin V-FITC/PI double labeling and the cell cycle was flow cytometrically analyzed.Compared with control cells,LRIG3 mRNA expression in U251 and U87 cells transduced with pLVX-DsRed-LRIG3-Monomer-N1 were increased by 77.6％ and 129.7％,and LRIG3 protein expression was raised by 141.3％ and 322.7％,respectively.Cell cycle analysis showed that LRIG3 over-expression increased the percentage of cells at G0/G1 phase (P＜0.01).Over-expressed LRIG3 could significantly promote the apoptosis of U87 and U251 cells (P＜0.05).These findings suggest that the over-expression of LRIG3 could arrest the cell cycle in G0/G1 phase,and promote apoptosis of U87 and U251 cells.