食管癌细胞放射诱导前后化疗敏感性变化及相关机制研究

Change of chemosensitivity and mechanisms of human radioresistance esophageal carcinoma cells before and after induction by radiation

目的:探讨食管癌细胞放射诱导前后对化疗药物敏感性及耐药基因ERCC1表达的变化,分析ER-CC1的表达与化疗敏感性变化的关系。方法:采用[60Co]-γ射线反复多次照射食管癌细胞株EC9706,建立放射抗拒食管癌细胞株EC9706-R。MTT法测定EC9706和EC9706-R对顺铂的IC50,计算耐药指数。免疫细胞化学(SP)和RT-PCR法测定ERCC1蛋白和mRNA在2种细胞中的表达。结果:EC9706细胞对顺铂的IC50是(1.480±0.012)mg/L,EC9706-R细胞的IC50是1.836±0.008 mg/L(P<0.05),耐药指数为:1.240±0.015;ERCC1蛋白在2种细胞中染色强度指数分别为2.838±0.055和2.898±0.039,两者无统计学差异(P>0.05)。ERCC1在这2种细胞中mRNA表达的特异性基因条带与β-actin基因条带的密度比值分别为:1.168±0.068和1.143±0.089(P>0.05)。结论:诱导建立的食管癌放射抗拒细胞较亲本细胞的化疗敏感性下降,而耐药基因ERCC1的表达水平不随细胞对放化疗敏感性的变化而变化。

AIM ： To investigate the change of chemosensitivity of esophageal carcinoma cells before and after induction by radiation, and to detect the excision repair cross complementation group 1 （ERCC1） gene before and after induction, and further to analyze the relationship between ERCC1 expression and chemosensitivity. METHODS： The esophageal carcinoma cell EC9706 was radiated repeatedly by a long- term, intermittent [ 60Co ] -γ/radiation to induce the radioresistance esophageal carcinoma cell EC9706 -R. The IC50 and resistant index （RI） of EC9706 and EC9706 -R were detected by MTT assay. The expression of ERCC1 was examined by immunocytochemistry and RT -PCR. RESULTS： The IC50 of EC9706 and EC9706 - R cells to cisplatin were （ 1. 480±0. 012） mg/L and （ 1. 836 ±0. 008） rag/L, respectively （P 〈0.05）, and the RI was 1. 240 ±0. 015. The tinctorial scores of ERCC1 protein in EC9706 and EC9706- R were 2. 838 ±0. 055 and 2. 898 ± 0. 039 （ P 〉 0. 05 ）, and the relatively quantities （IDV） of ERCC1 mRNA in EC9706 and EC9706 -R cells were 1. 168 ±0. 068 and 1. 143±0. 089 （P 〉0. 05 ）. SP and RT- PCR did not display visible difference in protein level and mRNA level. CONCLUSION： The chemosensitivity of EC9706 - R cells to cisplatin is decreased compared with EC9706 cells, but ERCC1 expression does not change with the radioresistance and chemoresistance.