Small interfering RNA targeting Bcl-2 enhances the inhibitory effects of MTX on transplanted human lymphoma in nude mice / 第二军医大学学报

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 (P<0.05). The tumor weight of mice in Bcl-2 shRNA plus MTX group was significantly lower than those in negative shRNA and blank plasmid group (P<0.05). 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 (P< 0.05). 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 (P<0.05), 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.