OBJECTIVETo construct a small interfering RNA (siRNA) targeting mouse vascular endothelial growth factor receptor-2 (VEGFR2) and study its serum stability and gene silencing efficiency in vitro.

METHODSThe synthesized siRNA targeting VEGFR2 (siVEGFR2) diluted in RNase-free water was mixed at a 1:1 ratio with fresh serum and incubated at 37 degrees celsius;. Gel electrophoresis was performed to determine the integrity of siVEGFR2 incubated for different time lengths. Oligofectamine 2000 was used to mediate siVEGFR2 transfection of MS1 cells, and semi-quantitative RT-PCR was used to evaluate VEGFR2 gene silencing effect induced by the siRNA.

RESULTSThe naked siRNA incubated in serum underwent gradual degradation with prolonged incubation time and became virtually undetectable after 24 h. Transfection of MS1 cells with siVEGFR2 significantly down-regulated the expression of VEGFR2 mRNA in comparison with the blank group and control siRNA transfection group (P<0.001), while no significant difference was found in VEGFR2 mRNA levels between the latter two groups (P=0.157).

CONCLUSIONThe naked siRNA is unstable in serum and not suitable for direct administration in vivo. The designed siRNA can effectively silence the VEGFR2 gene expression in MSI cells in vitro.