[Suppression of insulin-like growth factor-1 receptor by RNA interference inhibits cell growth in vitro and induces chemosensitization of HO8910PM cell to cisplatin].

OBJECTIVE: To assess the effect of suppression of insulin-like growth factor-1 receptor (IGF1R) in HO8910PM cell line by small interference RNA (siRNA). METHODS: Transfection of siRNA using lipofectamine 2000 was conducted to silence IGF1R gene expression, the expression levels of IGF1R mRNA and protein were evaluated, and the effects on the cell cycles at 48 hours of transfection were assessed by real-time PCR, western blot and flow cytometry (FCM) assay respectively. The cell growth was detected by cell counting kit-8 (CCK-8) at 24, 48, 72, 96 hours of transfection. After 24 hours of transfection, the cells were cultured with different concentrations of cisplatin (DDP) for 24 hours, the cell growth inhibition rate was evaluated by CCK-8. Following incubation with 10 microg/ml DDP for 24 hours after 24 hours of transfection, the apoptosis cells and the protein expression level of apoptosis-related gene, B cell leukemia/lymphoma 2 (Bcl-2), were identified by FCM and western blot respectively. RESULTS: (1) Expression levels of IGF1R mRNA and protein were markedly decreased respectively at 48 hours of transfection IGF1R siRNA. (2) Suppression of IGF1R accompanied the reduction of cell growth at 48, 72, 96 hours of transfection with IGF1R siRNA, absorbance were 1.71+/-0.13, 2.32+/-0.23, 2.79+/-0.28 respectively (P<0.01). (3) IGF1R siRNA induces arrest of G2 phase, the G2 phase rate of cells were 24.37% (P<0.05). (4) Following treatment with 2.5, 5, 10, 20 microg/ml DDP for 24 hours after 24 hours of transfection, the cell growth inhibition rates were (25.94+/-0.08)%, (40.25+/-0.05)%, (59.48+/-0.03)% and (74.18+/-0.08)% respectively (P<0.01). (5) Treatment with 10 microg/ml DDP for 24 hours after 24 hours of transfection, induces 17.95% of cells apoptosis (P<0.05), and decreases Bcl-2 protein level. CONCLUSION: RNA interference of IGF1R gene induces the IGF1R silence in HO8910PM cell line significantly, inhibits cell growth in vitro, arrests the G2 phase, and enhances the chemosensitization to DDP.