食管鳞癌细胞系核苷酸还原酶亚单位M1的表达水平与细胞对吉西他滨敏感性的关系

Relationship between the level of RRM1 expression and the sensitivity to gemcitabine in the esophageal squamous cell carcinoma cell lines

目的探讨食管鳞癌细胞系核苷酸还原酶亚单位M1（RRM1）表达水平与细胞对吉西他滨（GEM）敏感性的关系。方法选用4个人食管鳞癌细胞系Eca-109、Kyse-150、Kyse-450和9706，采用Western blot和逆转录聚合酶链反应（RT—PCR）检测各细胞系的RRM1表达水平，采用细胞毒性试验检测各细胞系对GEM的敏感性。以50nmoL／L GEM持续培养Kyse-450细胞，检测不同时点存活细胞RRM1表达水平的变化。应用RNA干扰技术下调RRMl表达水平后，检测细胞对GEM敏感性的变化。结果GEM作用48h，Eca-109、Kyse-150、Kyse-450和9706细胞的IC50分别为（0．92±0．17）、（0．48±0．11）、（0．29±0．06）和（0．02±0．01）mmol／L。RT—PCR和Western blot结果均显示，Eca-109细胞系的RRM1表达水平最高，其次是Kyse-150和Kyse-450，9706细胞系的RRM1表达水平最低。50nmol／L GEM持续培养Kyse-450细胞后，存活细胞的RRM1水平随着培养时间的延长而逐渐增高。转染RRM1 siRNA的Kyse-450细胞RRM1蛋白的表达水平显著降低，而对GEM的敏感性提高了4．26倍。结论食管鳞癌细胞系RRM1的表达水平与细胞对GEM的敏感性相关，RRM1表达水平低的细胞对GEM相对敏感。

Objective Ribonucleotide reductase subunit M1 （RRM1） is the intracellular target of gemcitabine （GEM）. The aim of this study is to explore the relationship between the level of RRM1 expression and the sensitivity to GEM in the esophageal squamous cell carcinoma cell lines. Methods Four esophageal squamous cell carcinoma cell lines （Kyse-150, Kyse-450,9706 and Eca-109） were cultured in vitro. In the same period, RRM1 expression level was measured by RT-PCR and Western blot, and cell sensitivity to GEM was determined by CCK-8 assay. The relation between cell sensitivity and RRM1 expression was further analyzed. Kyse-450 ceils were continuously cultured in the medium containing 50 nM GEM. RRM1 expression was measured at different time points to monitor the dynamic changes in the surviving cells. Inhibition of RRM1 expression by RNAi method was applied and the effect on GEM- sensitivity was further examined. Results The IC50 of Eca-109, Kyse-150, Kyse-450 and 9706 cells were （0.92 ±0. 17）, （0.48 ±0. 11）, （0.29±0.06） and （0.02±0.01） mmol/L, respectively. The expressions of RRM1 protein and mRNA of Eca-109 cell line were the highest detected by Western blot and RT-PCR, followed by Kyse-150 and Kyse-450, and the lowest one was 9706 cell line. When Kyse-450 cells were continuously treated with 50 nmol/L GEM, the level of RRM1 protein was increasing in the surviving cells. RRM1 siRNA could effectively knock down the expression of RRM1 and significantly increase the cell sensitivity to GEM （P = 0. 035 ）. Conclusion The level of RRM1 expression corelates with the cell sensitivity to gemcitabine. The cells with a lower level of RRM1 expression are more sensitive to gemcitabine.