目的：观察siRNA沉默COX-2基因增强口腔癌耐长春新碱细胞株KB/VCR对长春新碱的敏感性。方法将KB/VCR细胞分为COX-2 siRNA组、阴性对照组及空白对照组，RT-PCR检测COX-2 mRNA和MDR-1 mRNA的表达，流式细胞术检测细胞内Rho-123的蓄积量，MTT法检测细胞活力。结果 COX-2 siRNA能增强长春新碱对KB/VCR细胞的生长抑制作用（P<0.01），同时有效地抑制COX-2 mRNA和MDR-1 mRNA的表达及抑制P-糖蛋白（P-gp）的功能。COX-2 siRNA抑制COX-2基因表达与抑制P-gp的外排功能及与抑制MDR-1 mRNA的表达均呈正相关。结论 siRNA沉默COX-2基因可显著增强KB/VCR细胞对长春新碱的敏感性，其作用与下调节MDR-1基因表达及抑制P-gp功能有关。%Objective To investigate the effect of small interfering RNA (siRNA)-mediated COX-2 gene silencing in enhancing the chemosensitivity of KB/VCR cell lines. Methods KB/VCR cells were trasnfected with COX-2 siRNA were examined for expressions of COX-2 and MDR-1 mRNAs with RT-PCR and for Rho-123 accumulation using flow cytometry. MTT assay was used to analyze the proliferation of the transfected KB/VCR cells. Results Compared with the negative and blank control groups, COX-2 siRNA transfection resulted in significant growth inhibition of KB/VCR cells exposed to vincristine (P<0.01), down-regulated the expressions of COX-2 and MDR-1 mRNAs, and obviously increased Rho-123 accumulation in KB/VCR cells. Conclusion COX-2 gene silencing can enhance the chemosensitivity of KB/VCR cells to vincristine, the mechanism of which may involve down-regulated MDR-1 gene expression and inhibition of P-glycoprotein activity.
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