缺氧诱导鼻咽癌细胞株CNE2化疗耐药及其机制

目的：探讨缺氧环境下人鼻咽癌多药耐药相关基因和缺氧诱导因子1α（HIF-1α）的表达和意义,从而部分阐明鼻咽癌发生多药耐药的机制,为逆转鼻咽癌耐药提供新的分子靶点.方法：将人鼻咽癌细胞系CNE2分别行不同时间低氧培养,MTT法检测CNE2对紫杉醇、顺铂及5-氟尿嘧啶的耐药倍数;流式细胞仪检测缺氧与常氧下细胞的凋亡情况.应用RT-PCR和Western Blot分别检测每组CNE2细胞中多药耐药相关基因（mdr1）、多药耐药相关蛋白1（MRP1）和HIF-1α在mRNA和蛋白水平的表达.结果：缺氧培养48 h,CNE2对紫杉醇、顺铂和5-氟尿嘧啶的耐药倍数较常氧分别提高2.14,1.86,1.43倍,且药物引起的凋亡减少.在缺氧组,随着缺氧时间的延长,CNE2细胞中多药耐药相关基因mdr1,MRP1的表达均逐渐增高,而且这些多药耐药相关基因的表达与HIF-1α的表达呈同步化改变.结论：缺氧可上调鼻咽癌细胞内的核转录因子HIF-1α以及多药耐药相关基因的表达,从而诱导鼻咽癌产生多药耐药性.核转录因子HIF-1α和这些多药耐药相关基因可能成为逆转鼻咽癌耐药的新的分子靶点.

Hypoxia-induced chemotherapy resistance in nasopharyngeal carcinoma CNE2 cell line and its mechanism

AIM：To explore the mechanism of multidrug resistance of nasopharyngeal carcinoma induced by hypoxia and the potential role of hypoxia-inducible factor-1α（HIF-1α） and multidrug resistance related genes.METHODS：Human nasopharyngeal carcinoma cell lines CNE2 cells were exposed to hypoxia.MTT assay was used to investigate resistance index of CNE2 cells to paclitaxel,cisplatin and 5-FU.Cell apoptosis was measured by flow cytometry.The expressions of multidrug resistance gene（mdr1）,multidrug resistance protein（MRP1） gene and hypoxia-inducible factor-1α（HIF-1α） at the mRNA and the protein levels analyzed by RT-PCR and Western-blot technique.RESULTS：After exposed to hypoxia for 48 h,Paclitaxel,Cisplatin and 5-Fu resistance of CNE2 was increased 2.14,1.86 and 1.43 folds than that of in normoxia,respectively.The apoptosis of CNE2 cells in hypoxia was quite decreased after CNE2 exposed to Paclitaxel（8 nmol/L）.In the hypoxia group,the expressions of mdr1,MRP1 were stepped up correlating to the deg.ree of hypoxia,especially the prominent increase in the expression of MRP1.Furthermore,they were synchronous with the changes of the expression of HIF-1α.Also the increased expression of mdr1 and MRP1gene was observed.CONCLUSION：Resistance of nasopharyngeal carcinoma to chemotherapeutics could be induced by hypoxia.Hypoxia induced the expressions of HIF-1α and the related multidrug resistance genes.HIF-1α and these related multidrug resistance genes could be potential molecular targets for reversing multidrug resistance of nasopharyngeal carcinoma.