Objective:To confirm feasibility of Cyclin D1 gene as a new target for cancer gene therapy and to verify the effectiveness of shRNA expression vector-mediated gene silencing.Methods:A RNA interference DNA template targeting Cyclin D1 gene was designed and synthesized.By ligation,the fragment was inserted into Pgenesil-1-U6 to constract the recombinant plasmid Pgenesil-shRNA-Cyclin D1.The identiffed recombinant plasmid was transfected into ACHN cells with lipofactamine.Cyclin D1 mRNA and protein expression was analyzed by RT-PCR and western-blotting.MTT method was used for observing cell proliferation and drawing growth curve.The cell cycle and ratios of apoptotic cell were assessed by flow cytometric detection.The ability of invasion of cell migration was detected by Transwell chamber invasive models.Results:The plasmid was constructed successfully.After interference,The expression rate of Cyclin D1 mRNA decreased to 0.10±0.04 in Cyclin D1-shRNA(experimental)group and were significantly lower than Pgenesil-NC(negative)group(0.92±0.03)and ACHN(blank control)group(0.94±0.04)(P