Small interfering RNA targeting Bcl-2 enhances the inhibitory effects of MTX on transplanted human lymphoma in nude mice

Abstract

Objective:To explore whether short hairpin RNA(shRNA) targeting Bcl-2 can enhance the inhibitory effect of methotrexate(MTX) on growth of subcutaneously-transplanted human lymphoma in nude mice.Methods: Recombinant shRNA expression vector targeting the coding region of Bcl-2 mRNA was constructed and preserved in our lab.Human lymphoma Raji cells were injected subcutaneously into 45 nude mice to establish lymphoma models.The polyethylenimine(PEI)/shRNA complex and(or) MTX were injected into tumors.The influence of Bcl-2 shRNA and(or) MTX on tumor growth was observed.The animals were sacrificed 21 days after administration of drugs and the tumors were removed and weighed;the tumor inhibitory rate was calculated.H-E staining was used to observe the pathological morphology of the tumor.The expression of Bcl-2 mRNA in the tumor tissues was examined by RT-PCR.Results: The tumor growth was significantly slower in Bcl-2 shRNA/MTX group than in Bcl-2 shRNA or MTX alone groups(P0.05).The tumor weight of mice in Bcl-2 shRNA plus MTX group was significantly lower than those in negative shRNA and blank plasmid group(P0.05).The inhibition rate of tumor growth in Bcl-2 shRNA/MTX was significantly higher than those in the Bcl-2 shRNA or MTX alone groups(P0.05).H-E staining showed obvious apoptosis and necrosis in Bcl-2 shRNA group and MTX group.RT-PCR result showed that the expression of Bcl-2 mRNA in tumor cell suspension was significantly decreased in Bcl-2 shRNA group(P0.05),and kept unchanged in the control group.Conclusion: The shRNA targeting Bcl-2 can enhance the inhibitory effect of MTX on the growth of subcutaneously-transplanted human lymphoma in nude mice.