Regulation of multidrug resistance by ribosomal protein L6 in gastric cancer cells

Ribosomal proteins (RP) L6 was previously identified as an up-regulated gene in multidrug-resistant gastric cancer cells SGC7901/ADR comparing to its parental cells SGC7901 by subtractive hybridization. The aim of this study was to explore the roles of RPL6 in multidrug resistance (MDR) in gastric cancer cells. Northern and Western blot analysis confirmed that RPL6 was overexpressed in SGC7901/ADR cells. By gene transfection, RPL6 was genetically up-regulated in SGC7901 or down-regulated in SGC7901/ADR cells. Up-regulation of RPL6 was associated with enhanced resistance to multiple anticancer drugs (adriamycin, vincristine, etoposide, 5-fludrouracil and cisplatin) and to adriamycin-induced apoptosis. Down-regulation of RPL6 reversed MDR and sensitized cells to adriamycin-induced apoptosis. Alteration of RPL6 showed no obvious influence on intracellular adriamycin accumulation, glutathione content and expression of glutathione S-transferase. RPL6 could up-regulate Bcl-2 and down-regulate Bax in cells. Toge...