GRP78表达下调可降低肺腺癌细胞对VP-16的耐药

Down-regulation of GRP78 Enhances Chemotherapy Sensitivity to VP-16 in Lung Adenocarcinoma

背景与目的GRP78(Glucose-regu lated protein78)是GRPs家族的成员之一,其高表达与某些肿瘤细胞化疗耐药相关。本研究旨在探讨在BAPTA-AM作用下肺腺癌SPCA-1细胞GRP78表达水平的变化及GRP78表达下调与细胞对VP-16耐药的相关性。方法将SPCA-1细胞随机分为BAPTA-AM处理组、A23187处理组及对照组。采用RT-PCR和免疫荧光细胞化学方法分别检测各组细胞中GRP78在核酸和蛋白水平的表达。采用流式细胞仪测定细胞在化疗药物足叶乙甙(VP-16)作用下的细胞生存率。结果与对照组和A23187处理组相比,BAPTA-AM处理组细胞GRP78在核酸和蛋白水平的表达均明显降低,而其在VP-16作用下的细胞凋亡率则明显升高(细胞凋亡率:BAPTA-AM处理组为10.84±0.86;对照组为6.85±0.20;A23187处理组为4.95±0.19;P<0.01)。结论BAPTA-AM能够抑制SPCA-1细胞GRP78的表达,GRP78表达下调能够提高SPCA-1细胞对VP-16的敏感性。因此,采用化学药物或反义RNA等方法抑制GRP78的表达可能成为未来治疗肺癌的新手段。

Background and objective GRP78,a member of GRPs,plays a critical role in chemotherapy resistance in some cancers.To investigate the relationship between the expression of GRP78 and resistance to anti-cancer drug VP-16 in vitro in lung adenocarcinoma SPCA-1 cell line.Methods SPCA-1 cells were divided into three groups：BAPTA-AM-treated group,A23187-treated group and the control group.RT-PCR and immunofluorescence were used to analyze the expression of GRP78 at both mRNA and protein levels,respectively.Cell apoptosis was analyzed by flow cytometry in order to evaluate the therapeutic sensitivity to VP-16.Results The expression of GRP78 at both protein and mRNA levels in the BAPTA-AM-treated cells dramatically decreased as compared to that of both A23187-treated and control groups.After treatment by VP-16,the per-centages of apoptotic cells were 10.84±0.86,6.85±0.20,4.95±0.19 in BAPTA-M-treated group,the control group and A23187-treated group,respectively.Conclusion BAPTA-AM is highly effective in the inhibition of GRP78,down-regulation of GRP78 can significantly increase the sensitivity of adenocacinoma lung cancer to VP-16.All these suggest that inhibition of the expression of GRP78 by chemicals such as BAPTA-AM or anti-sense RNA may be a new therapeutic strategies to lung cancer.