RNA interference-mediated knockdown of insulin-like growth factor-1R inhibits proliferation of human gastric cancer cells

Objective To study the effects of insulin-like growth factor (IGF)-1R interference on proliferation of MKN28 gastric cancer cells.Methods Small interfering RNA (siRNA) targeting IGF-1 R mRNA was obtained by in vitro transcription and transfected into cells with lipofectin.The survival of the transfected cells was detected by using methyl thiazol tetrazolium (MTT) assay.The IGF-1R,phosphatidylinositol 3 kinase (PI3K),protein kinase B (Akt),p21 and integrase interacting molecule 1 (INI1) expression levels were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.Cell cycle of siRNA group was determined by flow cytometry (FCM).Results Inhibition of IGF-1R effectively inhibited the proliferation of MKN28 cells.The expression levels of IGF-1 R,PI3K and Akt mRNA and proteins were significantly inhibited,while those of p21 and INI1 were up-regulated in MKN28 cells in siRNA group as compared with control group.The percentage of cells in G0/G1 phase was significantly higher in siRNA group than in control group,2-4 d the cell proliferation rate of siRNA-IGF-1R were 31.12％,36.22％ and 42.03％,the difference has statistical significance (P ＜ 0.05).Conclusion IGF-I R gene interference could inhibit proliferation of MKN28 cells by regulating PI3K,Akt,p21 and INI1 expression. Key words: Gastric cancer;  Insulin-like growth factor-1 ;  Proliferation ;  Small interfering RNA