摘要
目的模拟临床放射方法对人鼻咽鳞癌CNE细胞分次照射，检测照射前、后CNE细胞肿瘤多药耐药蛋白P-gp及其编码的基因MDR1的表达和功能。方法对人鼻咽鳞癌CNE细胞进行体外培养，待细胞进入指数生长期后模拟临床放疗方法进行X射线分割照射，2Gy／（d·f^-1），连续5d，总剂量10Gy。于照射前、照射后4、8、13、17和21d分别收取标本进行检测。利用RT-PCR、免疫细胞化学检测照射前、后人鼻咽鳞癌CNE细胞MDR1及P-gp的表达；MTT法检测其耐药指数（RI）的变化，评价P-gp的功能。结果人鼻咽鳞癌CNE细胞MDR1基因照射前呈弱表达，照后4d过度表达，8d到21d表达逐渐降低，与照射前比较，差异有统计学意义（P〈0．05）；其编码的蛋白产物P-gp照射前、照射后4和8d呈弱表达，13至21d表达增高，P-gp迟于MDR1基因高表达。MTT法检测耐药指数结果显示：照射前、照射后4和8d RI值均为1，13、17和21d RI分别增高为8、10和11．2，RI值变化的情况与P-gp的变化情况相一致。结论人鼻咽鳞癌CNE细胞照射前MDR1及P-gp呈弱表达，有原始的低度耐药性；照射后MDR1及功能性P-gp高表达并且持续一段时间。
Objective To mimick a clinical fractionated protocol of exposure to X-radiation in vitro in order to investigate the changes in the function of MDR1 and P-gp in nasopharyngeal carcinoma （NPC） CNE cell before and after irradiation to determine the sequential order of radiotherapy and chemotherapy or the time of chemotherapy after radiotherapy in the treatment of NPC. Methods Exponentially growing CNE cells were treated with fractionated X-radiation with total dose of 10 Gy （2 Gy per day for 5 days consecutively） in vitro. The expression of MDR1 gene was examined in CNE cells before irradiation and on days 4,8,13,17 and 21 after irradiation by RT-PCR, and its protein P-gp were detected by immunocytochemistry. The function of muhidrug resistance protein P-gp was examined by MTT method. Results Expression of MDR1 gene was below the level of detection before irradiation. Irradiation induced an overexpression of MDR1 gene on day 4, expression of MDR1 was decreased from day 8 to day 21. The overall expression of MDR1 was significantly more than that before irradiation（ P 〈 0.05） . Expression of P-gp was below the level of detection before irradiation, which demonstrated that irradiation induced an overexpression of P-gp. This overexpression was increasd from day 8 to day 21. The overpression of MDR1 gene was maintained druing a short period, however, the emergence of overpression of protein P-gp was later than that of MDR1 gene. Resistance index was 1 for beth pre-irradiation and on day 8, and up to 8,10,11.2 on days 13, 17 and 21, respectively. The change of resistance index was accordant with the condition of overexpression of P-gp . Conclusions Expression of P-gp in nasopharyngeal carcinoma （NPC） CNE cell was below the level of detection before irradiation. Irradiation can induce an overexpression of MDR1 gene and its protein P-gp in CNE cells. The overexpression of MDR1 gene and its protein P-gp lasted a long tenn.
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2007年第2期132-135,共4页
Chinese Journal of Radiological Medicine and Protection
基金
辽宁省科技攻关基金资助项目（20004225004-13）
