吉西他滨耐药胰腺癌细胞系的耐药机制  

The mechanism of resistance to 2′,2′-difluorodeoxycytidine (gemcitabine) in a pancreatic cancer cell line

作　　者：要洁[1] 冯奉仪[1] 林晨[2] 张雪燕[2] 付明[2] 梁萧[2] 杨莹[3] 

机构地区：[1]中国医学科学院中国协和医科大学肿瘤研究所肿瘤医院内科 [2]中国医学科学院中国协和医科大学肿瘤研究所分子肿瘤学国家重点实验室,北京100021 [3]首都医科大学附属复兴医院肿瘤内科

出　　处：《中华肿瘤杂志》2005年第12期721-726,共6页Chinese Journal of Oncology

摘　　要：目的探讨吉西他滨耐药胰腺癌细胞系的耐药机制。方法应用免疫组织化学方法和逆转录PCR法(RT-PCR),对吉西他滨耐药细胞系的耐药机制进行了研究。选用沙尔威辛(SAL)进行逆转耐药实验,采用了RT-PCR法、流式细胞仪和MTT法,评估SAL逆转耐药的效果。结果免疫组织化学法显示,耐药细胞SW1990-GEM的P-糖蛋白(P-gp)表达为弱阳性,其亲本细胞SW1990为阴性。多药耐药相关蛋白(MRP)在两细胞系表达均为阴性。SW1990-GEM的多药耐药基因(mdr-1)在mRNA水平上的转录比其亲本细胞系SW1990增强;脱氧胞苷激酶(dCK)基因的转录减少;核苷酸还原酶(RR)基因的转录增强。经过SAL作用后,mdr-1在mRNA水平上的转录减少。流式细胞仪显示,经过4,30,60,90nmol/L SAL作用后,细胞内罗丹明123的蓄积累分别增加1.04,1.16,1.39,1.72倍。用4nmol/L SAL进行逆转吉西他滨耐药实验,未接受SAL处理的对照组对吉西他滨的IC50为203.72μmol/L;经SAL作用1h后再加吉西他滨组的IC50为121.36μmol/L(P=0.219);经SAL作用24h后再加吉西他滨组的IC50为121.64μmol/L(P=0.167)。结论胰腺癌细胞对吉西他滨耐药的原因与dCK减少有关,同时也与mdr-1和RR升高相关。SAL能够下调SW1990-GEM耐药细胞的mdr-1和P-gp表达,但低浓度的SAL不能逆转SW1990-GEM对吉西他滨的耐药。Objective To study the mechanism of resistance and its reversal to 2＇, 2＇- difluorodeoxycytidine （ gemcitabine ） in a pancreatic cancer cell line SW1990. Methods Immunohistochemistry and RT-PCR techniques were used to investigate the mechanism of drug resistance. Salvicine （SAL） was used to reverse the drug resistance in a gemcitabine-resistant pancreatic cancer cell line （SW1990-GEM）. RT-PCR, flow cytometry and MTF assay were employed to evaluate the effect of reversing drug resistance by salvicine. Results SW1990-GEM cells showed weak expression of P-glycoprotein （ P- gp） revealed by immunohistochemistry, while its parental SW1990 cells were negative. Both cell lines did not express multidrug-resistance-related protein （MRP）. As compared to the parental SW1990 cells, the mRNA expression of deoxycytidine kinase （dCK） was decreased while that of ribonucleotide reductase （RR） and mdr-1 was increased. With a concentration of 4 nmol/L, at one hr and 24 hr after SAL treatment, there was no change in mdr-1 mRNA expression, and the IC50 of gemcitabine was 121.36μmol/L and 121.64μmol/L, respectively. However, when the concentration of SAL was increased to 30, 60, and 90 nmol/L, there was a dose-dependent down-regulation of mdr-1 mRNA expression in SW1990-GEM cells. The accumulation of rhodamine 123 was concomitantly increased, and the IC50 of gemcitabine was correspondingly decreased. Conclusion The resistance to gemcitabine of a pancreatic cancer cell line is due to decreased expression of dCK and increased expression of RR and mdr-1. Salvicine, only in toxic concentrations, can reverse the drug resistance by down-regulating mdr-1 gene and P-gp expression.

关 键 词：吉西他滨 胰腺肿瘤 沙尔威辛 药物耐受性 

分 类 号：R735.9[医药卫生—肿瘤] R734.2[医药卫生—临床医学]