Abstract: This work aims to construct TOX3 gene lentiviral RNA interference（RNAi）vector and observe its effect on the proliferation of human breast cancer ZR-75-1cells. First,designing interference sequence targeting the TOX3,constructing vectors and then packaging lentiviral vectors and measuring the virus titer after sequence identification were conducted. Then the recombinant lentiviral vector was transfected into human ZR-75-1cells,the number of cells expressing GFP was observed under fluorescence microscope,and then the expression of TOX3 in the transfected ZR-75-1cells was detected by real time-PCR and Western blot. Finally,the effect of TOX3 on ZR-75-1 cells proliferation was measured by MTT assay and colony formation experiment. The results showed that the vector sequence of each group was confirmed correctly by gene sequencing,the virus titer was > 2×10⁸ TU/mL,and over 95% cells expressed GFP under the fluorescence microscope after being transfected,the expression of TOX3 mRNA and protein significantly reduced in the interference groups,particularly the interfere effect of TOX3-shRNA-3 group was the best,the proliferation and monoclonal ability of ZR-75-1cells decreased after the transfection. In sum,the study successfully constructed TOX3 gene lentiviral RNA interference vector,and the proliferation of ZR-75-1cells decreased after TOX3 was silenced.

Key words: TOX3 gene, lentiviralvector, RNA interference, ZR-75-1 cells