胃癌耐药细胞多药耐药基因表达上调中AP-1作用的研究

The Role of AP-1 in the Upregulation of the Multidrug Resistance Gene MDR1 in a Drug-Resistant Gastric Carcinoma Cell Line

目的:探讨人胃腺癌阿霉素耐药细胞系SGC7901/ADR中多药耐药(multi drug resistance,MDR)产生机制,为胃癌多药耐药机制的研究提供新靶点。方法:采用MTT法测定3种常用化疗药物顺铂、表柔比星、5-氟尿嘧啶在人胃癌细胞系SGC7901及其阿霉素耐药细胞系SGC7901/ADR中的作用;应用反转录聚合酶链反应(RT-PCR)技术检测SGC7901和SGC7901/ADR中mdr1、c-Jun的mRNA表达情况;转录因子AP-1分别转染入SGC7901和SGC7901/ADR中,应用双荧光素报告基因检测系统(Dual-Luciferase reporter assay system)检测其活性;Western Blot法检测P-gp、c-Jun在蛋白水平的表达。结果:SGC7901与SGC7901/ADR在化疗药物顺铂、表柔比星、5-氟尿嘧啶的不同浓度下作用72小时后,发现SGC7901/ADR中细胞的生存率无明显改变,而SGC7901的生存率却有显著的下降趋势;在mRNA水平对mdr1基因进行检测,SGC7901/ADR中的多药耐药基因的表达显著高于SGC7901,而P-gp在蛋白水平的检测中显示SGC7901/ADR相对与SGC7901,表达活性有明显升高;转录因子AP-1的表达分别在SGC7901及SGC7901/ADR中检测到,但SGC7901/ADR中AP-1的活性明显高于SGC7901;AP-1的主要组成成份c-Jun在SGC7901和SGC7901/ADR做mRNA及蛋白水平的检测,结果显示在SGC7901中未发现c-Jun的明显表达,而SGC7901/ADR中c-Jun的表达活性均显著升高。结论:在人胃腺癌阿霉素耐药细胞系SGC7901/ADR中有MDR的产生,同时伴多药耐药基因上调;转录因子AP-1的活性表达与胃癌细胞的多药耐药性密切相关,AP-1的表达高低可能是其形成机制之一。

Objective： To investigate the role of the muhi-drug resistanee gene MDRI in the Doxorubicin-resistant SGC7901/ADR gastric adenocarcinoma cell line. Methods： We used the MTT assay to determine the cell survival rate of SGC7901 human gastric careinoma cells and Doxorubicin-resistant SGC7901/ADR cells ＇after treatment with three kinds of commonly used chemotherapeutic drugs. Reverse transcription-polymerase chain reaction （RT-PCR） was employed to detect the mRNA level of mdrl and c-Jun in SGC7901 and SGC7901/ADR cells. Transcription factor AP-1 was transfected into SGC7901 and SGC7901/ADR cells, and tire transcription activity was assayed by a dual-luciferase reporter assay. The protein expression of P-gp and c-Jun was detected by Western blot, Results： The survival rate of SGC7901/ADR cells was significantly higher than that of SGC7901 cells. The mRNA level of mdrl and c-Jun was significantly higher in SGC7901/ADR cells than in SGC7901 cells. The transcription activity of transcription factor AP-1 was different between the two cell lines. The levels of P-gp anti c-Jun were higher in SGC7901/ADR cells. Conclusion： In the SGC7901/ADR cell line.multiple-drug resistance is increased and an upregulation of the MDR1 gene is observed. In gastric cancer, the activity of transcription factor AP-1 is related to the MDR of cancer cells. The expression of AP-1 may be involved in the mechanism of Doxorubicin resistance in gastric carcinoma cells.