In nasopharyngeal carcinoma cells, Epstein-Barr virus LMP1 interacts with galectin 9 in membrane raft elements resistant to simvastatin
In nasopharyngeal carcinoma cells, Epstein-Barr virus LMP1 interacts with galectin 9 in membrane raft elements resistant to simvastatin
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DOI：
10.1128/jvi.79.21.13326-13337.2005
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发表时间：
2005-11-01
影响因子：
5.4
通讯作者：
Busson, P
中科院分区：
文献类型：
--
作者：
Pioche-Durieu, C;Keryer, C;Busson, P
鼻咽癌（NPC）的病因学与eb病毒（EBV）有关，恶性鼻咽癌细胞具有EBV潜伏膜蛋白1 （LMP1）的一致表达，尽管表达不同。LMP1的运输和信号传递需要其结合到膜筏中。相反，筏环境可能会调节LMP1的活性。为了研究LMP1特异性的筏体伙伴，将C15鼻咽癌异种移植物的筏体提交LMP1的免疫沉淀制备，并结合质谱分析共免疫沉淀蛋白。通过这一过程，凝集素9（一种结合凝集素和霍奇金肿瘤抗原的β -半乳糖苷）被确定为LMP1的新伙伴。在NPC和ebv转化的B细胞（淋巴母细胞样细胞系[LCLs]）的全细胞提取物中，通过共免疫沉淀和Western blotting证实了LMP1与凝集素9的相互作用。利用HeLa细胞中表达的突变蛋白，LMP1以不依赖traf3的方式结合凝集素9。凝集素9在NPC活检和lcl中含量丰富，而在Burkitt淋巴瘤细胞中缺乏。在随后的实验中，用辛伐他汀处理鼻咽癌细胞，辛伐他汀是一种药物，据报道可以将LMP1从ebv转化的B细胞的膜筏中分离出来。我们发现辛伐他汀对鼻咽癌细胞筏中LMP1和凝集素9的分布没有显著影响。然而，辛伐他汀对鼻咽癌细胞具有高度的细胞毒性，无论LMP1是否存在。这表明辛伐他汀是治疗NPC的潜在有用药物，尽管它在NPC和LCL细胞中具有不同的作用机制。
Nasopharyngeal carcinomas (NPC) are etiologically related to the Epstein-Barr virus (EBV), and malignant NPC cells have consistent although heterogeneous expression of the EBV latent membrane protein 1 (LMP1). LMP1 trafficking and signaling require its incorporation into membrane rafts. Conversely, raft environment is likely to modulate LMP1 activity. In order to investigate NPC-specific raft partners of LMP1, rafts derived from the C15 NPC xenograft were submitted to preparative immunoprecipitation of LMP1 combined with mass spectrometry analysis of coimmunoprecipitated proteins. Through this procedure, galectin 9, a beta-galactoside binding lectin and Hodgkin tumor antigen, was identified as a novel LMP1 partner. LMP1 interaction with galectin 9 was confirmed by coimmunoprecipitation and Western blotting in whole-cell extracts of NPC and EBV-transformed B cells (lymphoblastoid cell lines [LCLs]). Using mutant proteins expressed in HeLa cells, LMP1 was shown to bind galectin 9 in a TRAF3-independent manner. Galectin 9 is abundant in NPC biopsies as well as in LCLs, whereas it is absent in Burkitt lymphoma cells. In subsequent experiments, NPC cells were treated with Simvastatin, a drug reported to dissociate LMP1 from membrane rafts in EBV-transformed B cells. We found no significant effects of Simvastatin on the distribution of LMP1 and galectin 9 in NPC cell rafts. However, Simvastatin was highly cytotoxic for NPC cells, regardless of the presence or absence of LMP1. This suggests that Simvastatin is a potentially useful agent for the treatment of NPCs although it has distinct mechanisms of action in NPC and LCL cells.