Lentiviral Vector-Mediated <i>In Vitro</i> Down-Regulation of Porcine Somatostatin Expression Using shRNA

Two shRNA sequences against porcine somatostatin (SST) were designed using software available on the NCBI website. The designed RNA sequences were chemically synthesized and cloned into lentiviral vectors (LV-siRNA1 and LV-siRNA2). Porcine somatostatin cDNA was amplified and cloned into pcDNA3.1 (pcDNA3.1-SST). LV-siRNA1 or LV-siRNA2 was cotransfected with pcDNA3.1-SST into NIH3T3 cells. Real-time RT-PCR for the detection of SST mRNA, revealed that LV-siRNA1 and LV-siRNA2 suppressed SST expression by 87.9% and 86.3% ( P < 0.01), respectively. In addition, radioimmunoassay (RIA) for direct detection of SST indicated that the suppression ratios for LV-siRNA1 and LV-siRNA2 were 55.1% and 51.6% ( P < 0.01), respectively. These data showed that the 2 shRNA sequences were effective in suppressing SST expression and may provide an approach to down-regulate both in vitro and in vivo expression of porcine SST.