| WANG Ruo-yu,WANG Hui,FAN Kai,et al.Expression of multidrug resistance gene and P-glycoprotein in nasopharyngealcarcinoma cells after irradiation[J].Chinese Journal of Radiological Medicine and Protection,2007,27(2):132-134 |
| Expression of multidrug resistance gene and P-glycoprotein in nasopharyngealcarcinoma cells after irradiation |
| Received:April 17, 2006 |
| DOI： |
| KeyWords:Nasopharyngeal neoplasm Fractionated irradiation Multidrug resistance gene P-glycoprotein |
| FundProject:辽宁省科技攻关基金资助项目(20004225004- 13) |
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| Abstract:: |
| 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 multidrug 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 both 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 term. |
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