Objective   To construct a recombinant lentiviral expression vector for RNA interference (RNAi) of human Snail gene and to study its effects on the proliferation and invasion of nasopharyngeal carcinoma cell line 5-8F.     Methods   The effective sequence of short hairpin RNAs (shRNA) targeting Snail gene was designed and cloned into the linear pLVTHM vector after enzyme digestion. After confirmation by DNA sequencing

5-8F cells were infected with the viral supernatants. The cells with stable Snail gene knock-down were separated by fluorescence activated cell sorter (FASC). The expression of Snail mRNA was detected by real time RT-PCR. MTT and cell invasion assay were used to detect the proliferation and invasion of 5-8F cells after plVTHM-siSnail transfection.     Results   The lentivirus vector plVTHM-siSnail was constructed successfully. The separated 5-8F-plVTHM-siSnail exhibited significant knock-down of Snail mRNA expression. Slower proliferation and decreased cells to permeate through the Matrigel were found after plVTHM-siSnail transfection (P0.05).    Conclusion   plVTHM-siSnail vector could down-regulate Snail gene expression in human nasopharyngeal carcinoma 5-8F cells and suppress its invasion and proliferation to some extent.