人层粘连蛋白受体调节胃癌细胞多药耐药性的实验研究

目的：探讨相对分子质量为67000的人层粘连蛋白受体（LR）对胃癌细胞多药耐药性（MDR）的调节作用及其机制。方法：应用DNA重组技术构建LR前体蛋白（LRP）的反义RNA表达载体,并借助脂质体将其导入胃癌MDR细胞SGC7901／VCR中。用Western印迹法检测ＬＲ在胃癌细胞中的表达,ＭＴＴ法测定细胞对化疗药物的敏感性,流式细胞仪测定细胞周期以及阿霉素在细胞内的蓄积和潴留。结果：转染LRP反义RNA表达载体显著降低了LR在SGC7901／VCR细胞中的表达。转染细胞（SGC7901／VCR－anLRP)对长春新碱、阿霉素、5－氟尿嘧啶和顺铂的敏感性明显升高,细胞内蓄积和潴留的阿霉素也明显增多。细胞周期分析表明,SGC7901／VCR－anLRP细胞发生了G1期阻滞,并出现了自发性凋亡。结论：LR可能通过影响药物蓄积和细胞凋亡参与对胃癌细胞MDR的调节。

Experimental study of multidrug resistance mediated by human laminin receptor in gastric cancer cells

Objective To study the mechanisms of multidrug resistance (MDR) mediated by human 67 000 laminin receptor (LR) with a relative molecular mas of 67 000 in gastric cancer cells. Methods Antisense RNA expression vector corresponding to LR precursor (LRP) was constructed by DNA recombinant technique, and transferred into gastric cancer MDR cells SGC7901/VCR with Lipofect AMINE. Western blot was employed to determine the LR expression level in gastric cancer cells. The sensitivity of gastric cancer cells to chemotherapeutic drugs was evaluated with MTT assay. Flow cytometry was used to analyze the cell cycle and to assess the mean fluorescence intensity of intracellular adriamycin in gastric cancer cells. Results Western blotting analysis demonstrated a decreased expression level of LR in SGC7901/VCR cells transfected with LRP antisense RNA expression vector. In comparison with the gastric cancer cells without transfection or transfected with invalid vector, LR down regulated transfectants (SGC7901/VCR anLRP) showed higher sensitivity to vincristine, adriamycin, 5 fludrouracil and cisplatin, and increased accumulation and retention of adriamycin. Cell cycle analysis suggested G1 block and spontaneous apoptosis of SGC7901/VCR anLRP cells. Conclusion LR might take part in mediation of MDR in gastric cancer cells through interfering with drug accumulation and cell apoptosis.