BACKGROUND AND OBJECTIVEThe expression levels of glucose-regulated protein 78 (GRP78) were elevated and correlated with resistance to chemotherapy drug VP-16 in lung cancer cells. However, little is known about the relationship between its expression and resistance to cisplatin in lung cancer cells. The aim of this study was to investigate the expression of GRP78 under the induction of A23187 and its significance in the resistance to anti-tumor drugs cisplatin in a human lung cancer SPCA-1 cell line.

METHODSRT-PCR and Western blot were used to analyze the expression of GRP78 at mRNA and protein levels in SPCA-1 cell line induced byA23187 at different concentrations (0, 1, 2, 4, 6 microM). MTT was used to determine the effect of cisplation on cell survival.

RESULTSThe expressions of GRP78 at both mRNA and protein levels were increased obviously in SPCA-1 cell line induced by A23187, with a manner of dose-dependent of A23187 to a great degree; MTT assay showed that the cell survival rate of the A23187-induced group decreased significantly compare to the control group, also with a concentration-dependent manner of A23187.

CONCLUSIONThe expression of GRP78 at both mRNA and protein levels were increased obviously in SPCA-1 cell line induced by A23187. The enhancement of GRP78 showed a negative correlation with the cell survival rate treated by cisplatin. All these indicated that overexpression of GRP78 can enhance the sensitivity to cisplatin and there is correlation between the expression of GRP78 and resistance to cisplatin of human lung cancer SPCA-1 cell line.