Effects of IGF1R siRNA on chemosensitivity to gemcitabine in human pancreatic cancer cells

Abstract

Objective To construct the lentiviral expression vector for RNA interference of insulin like growth factor-1 receptor (IGF1R) gene in human pancreatic cancer cells and to evaluate its effect on chemosensitivity to gemcitabine.Methods Three sequences of RNA interference targeting IGF1R gene were designed, synthesized and cloned into the pFU-GW-RNAi vector. After transfection of 293T cells with lentiviral vector, the lentivirus was produced and the titer of virus was tested. Panc-1 cells were infected with the lentivirus and the expression of IGF1R mRNA in Panc-1 cells was detected by real-time quantitative polymerase chain reaction (PCR). The changes of gemcitabine sensitivity after RNA interference were examined by methyl thiazol tetrazolium (MTT) assay. In vivo nude mice tumorigenicity model was used to determine the effect of RNA interference targeting IGF1R gene combined with or without gemcitabine on growth inhibition of xenograft tumors.Results A recombinant lentiviral vector expressing shRNA against IGF1R gene was obtained. After RNA interference, the median inhibition concentration (IC50) of gemcitabine against Panc-1 cells was reduced from (0.774±0.001) mg/L to (0.330±0.003) mg/L, indicating that the sensitivity to gemcitabine was increased by 2.35 times after interference. In vivo xenograft formation assay resulted in a significant growth-inhibiting effect by IGF1R RNA interference. Furthermore, the RNA interference targeting IGF1R gene enhanced the antiproliferative effect of gemcitabine on nude mice xenografts.Conclusion The sensitivity of Panc-1 cells to gemcitabine could be enhanced by RNA interference targeting IGF1R gene. Key words: Insulin like growth factor-1 receptor; Gemcitabine; Pancreatic carcinoma; Lentivirus