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

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.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.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 with out transfection or transfected with invalid vector, LR down-regulated transfectants (SGC7901/VCR-anLRP) showed higher sensitivity to vincristine, adriamycin, 5-fluodrouracil and cisplatin, and increased accumulation and retention of adriamycin. Cell cycle analysis suggested G1 block and spontaneous apoptosis of SGC7901/VCR-anLRP cells.LR might take part in mediation of MDR in gastric cancer cells through interfering with drug accumulation and cell apoptosis.