中文摘要：

目的研究鞘磷脂合酶2（sphingomyelin syndmse2，SMS2）缺损对人结肠癌细胞（colon cancer cell．Caco-2）中药物转运体P-精蛋白（P-glycoprotein，P-gp）及多药耐药相关蛋白2（multidrug resistance-associated protein2．MRP2）的表达与功能的影响。方法SMS2特异性siRNA转染至Caco-2细胞。采用RT-PCR和realtime PCR检测SMS2-特异性siRNA的干扰效率；采用Western blot法检测siRNA转染后P-gp和MRP2蛋白表达的变化；采用胞内蓄积试验。通过HPLC检测P-gp及MRP2专一性底物罗丹明123及普伐他汀的蓄积含量，分析下涮SMS2水平对Caco-2细胞中Pgp及MRP2功能的影响。结果应用siRNA下调SMS2水平后．P-gp和MRP2的蛋白质水平均显著下调；胞内蓄积实验结果挂示罗丹明123及普伐他汀的蓄积量明显增加，说明P-gp和MRP2的外排功能减弱。结论SMS2基因表达下调对Caco-2细胞中P-gp和MRP2的表达以及功能均有显著影响。

英文摘要：

Objective To study the effect of sphingomyelin synthase 2 （SMS2） defect on the expression and function of drug transporters P-glycoprotein （P-gp） and multidrug resistance-associated protein 2 （MRP2） in human colon cancer （Caco-2） cells. Methods SMS2-specific siRNA was transfected into Caco- 2 cell. RT-PCR and real-time PCR were employed to detect the efficiency of siRNA. Western blot was used to examine the protein expressions of P-gp and MRP2. Intracellular accumulation experiment was carried out to evaluate the effect of SMS2 down-regulation level on the functions of P-gp and MRP2 in Caco-2 cells. HPI.C analysis was used to deeect the accumulation amounts of parvastain and rhodamine 123,the specific substrates of P-gp and MRP2. Results The expressions of P-gp and MRP2 were down-regulated in SMS2 knockdown cells treated by siRNA. Cellular accumulation experiments revealed that the excretion function of P-gp and MRP2 in SMS2 deficient cells was decreased,as the accumulation of rhodamine 123 and parvastain was increased significantly. Conclusions The down-regulation of SMS2 gene on the expression and function of P-gp,MRP2 in Caco-2 cell.