Abstract: Objective To construct recombinant plasmids containing microRNA targeting the Pokemon gene and investigate the effects of miRNA-mediated downregulation of the Pokemon gene on the proliferation and cell-cycle progression of colorectal cancer cells,Lovo.Methods Four miRNAs were designed according to the coding sequence of the Pokemon gene and used to construct recombinant plasmids.The recombinant plasmids were transfected into Lovo cells using Lipofectamine 2000.The expression of Pokemon mRNA was detected by Quantitative polymerase chain reaction(qPCR)assays.Cellular proliferation was measured by methyl thiazolyl tetrazolium(MTT)assay.Cell-cycle progression was analyzed by flow cytometry.Results Four recombinant plasmids were successfully constructed,named mR22-1,mR22-2,mR22-3 and mR22-4.The expression of Pokemon mRNA was obviously downregulated in Lovo cells transfected with the recombinant plasmids.The best silencing effect was achieved in cells transfected with the mR22-1 plasmid.The expression levels of Pokemon mRNA were downregulated by 50%±2.7%.MTT assay indicated that mR22-1 transfection could inhibit cellular proliferation.Flow cytometry assay indicated that mR22-1 transfection lead to Lovo cell cycle arrest in G1-phase.Conclusion The recombinant plasmids containing miRNA targeting the Pokemon gene specifically downregulate Pokemon expression.Pokemon gene can promote proliferation in Lovo cells.Results suggest that the microRNA interference developed in this study represents a novel anti-tumor strategy that may be applicable to most research involving cancer therapy and,thus,has promising potential as a colorectal cancer treatment.