Transactivation of the human NME5 gene by Sp1 in pancreatic cancer cells
Transactivation of the human NME5 gene by Sp1 in pancreatic cancer cells
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DOI：
10.1016/j.gene.2012.04.088
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发表时间：
2012-07-25
期刊：
影响因子：
3.5
通讯作者：
Zhang, Luyong
中科院分区：
文献类型：
--
作者：
Li, Fu;Jiang, Zhenzhou;Zhang, Luyong
非转移细胞5(NME5)是新近发现的属于NDPK样分子基因家族的基因，在睾丸和某些类型的人类肿瘤中高表达。目前的研究已经揭示了NME5的多种潜在功能，我们在以前的研究中已经报道了NME5与人胰腺癌细胞对吉西他滨的先天耐药有关。然而，NME5转录调控的机制尚未阐明。在本研究中，我们分析了人NME5基因的5‘侧翼区，发现其转录起始点(TSS)相对于其翻译起始密码子ATG有-35个碱基。5‘端单向缺失分析表明，NME5基因启动子近端位于-1051~+35个碱基之间。在启动子区域发现了两个功能GC盒(-300bp和-323bp)。在MIA Paca-2和293T细胞中，任一GC-box突变导致NME5启动子活性显著降低，而Sp1过表达则激活NME5启动子活性。电子计算机分析预测转录因子Sp1与两个GC盒结合，EMSA和CHIP证实了这一点。此外，我们还发现，与MIA Paca-2相比，Sp1在PAXC002中高表达，PAXC002是一种具有天然吉西他滨耐药的人胰腺癌细胞株，据报道NME5在PAXC002细胞中高表达，这表明Sp1诱导了PAXC002细胞中NEM5的表达。总之，我们的研究首次确定了胰腺癌中受Sp1转录因子调控的人NME5启动子。(C)2012爱思唯尔B.V.保留所有权利。
Non-metastatic cells 5 (NME5), a recently found gene belonging to the NDPK-like molecules gene family, is highly expressed in testis and some types of human cancer. Current studies have revealed diverse potential functions of NME5 and we have reported that NME5 is associated with innate resistance to gemcitabine in human pancreatic cancer cells in previous study. However, the mechanism underlying the transcriptional regulation of NME5 has not been elucidated yet. In this study, we analyzed the 5'-flanking region of the human NME5 gene and revealed its transcription start site (TSS) at -35 bp relative to its translation start codon ATG. Using 5' unidirectional deletion analysis, we demonstrated that the proximal promoter of NME5 is located within -1051 bp to +35 bp. Two functional GC-boxes (-300 bp and -323 bp) were identified within the promoter region. Mutation of either GC-box led to significant reduction in NME5 promoter activity, whereas overexpression of Sp1 activated NME5 promoter activity in MIA PaCa-2 and 293T cells. In silico analysis predicted that transcription factor Sp1 binds to both GC-boxes, which were confirmed by EMSA and ChIP. In addition, we found that compared with MIA PaCa-2, Sp1 was highly expressed in PAXC002, a well characterized human pancreatic cancer cell line with innate gemcitabine resistance where NME5 was reported to be highly expressed, indicating that Sp1 induces NEM5 expression in PAXC002 cells. In conclusion, our study characterized for the first time the human NME5 promoter which is controlled by Sp1 transcription factor in pancreatic cancer. (C) 2012 Elsevier B.V. All rights reserved.