Analysis of an alternative human CD133 promoter reveals the implication of Ras/ERK pathway in tumor stem-like hallmarks.
Analysis of an alternative human CD133 promoter reveals the implication of Ras/ERK pathway in tumor stem-like hallmarks.
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DOI：
10.1186/1476-4598-9-39
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发表时间：
2010-02-19
期刊：
影响因子：
37.3
通讯作者：
Tanaka S
中科院分区：
文献类型：
--
作者：
Tabu K;Kimura T;Sasai K;Wang L;Bizen N;Nishihara H;Taga T;Tanaka S
越来越多的研究支持干细胞在人类恶性肿瘤中的存在。这些细胞主要负责肿瘤的发生，因此被认为是根除肿瘤的潜在靶点。CD133已被确定为在各种人类肿瘤中丰富干细胞样群体的重要细胞表面标记物。为了揭示肿瘤细胞中干细胞样特征的分子机制，我们使用内源性表达CD133基因的人结肠癌Caco-2和滑膜肉瘤Fuji细胞分析了CD133基因的启动子。报道者分析显示，P5启动子位于人类CD133基因位点的远上游，在5个可能的启动子（P1至P5）中表现出最高的活性。缺失和突变分析发现P5区域的两个ETS结合位点对其启动子活性至关重要。电泳迁移率转移实验证明了核因子与ETS结合序列之间的特异性结合。过表达显性阴性形式的Ets2和Elk1导致P5活性显著降低。此外，用MEK/ERK特异性抑制剂U0126处理富士细胞也能显著降低CD133的表达，但对Caco-2细胞没有显著影响，提示CD133的表达有细胞类型特异性调节。相反，在Caco-2细胞中，U0126显著减少了TSLCs的另一个标志——侧群。最后，随着CD133 mRNA表达的增加，ras介导的正常人类星形胶质细胞的致癌转化赋予了干细胞样能力，形成神经球样集落。总之，Ras/ERK通路至少在一定程度上有助于维持和获得干细胞样标记，尽管其贡献的程度以细胞类型特异性的方式变化。这些发现有助于我们对肿瘤干性的全面认识，并促进人类恶性肿瘤根治性治疗的发展。
An increasing number of studies support the presence of stem-like cells in human malignancies. These cells are primarily responsible for tumor initiation and thus considered as a potential target to eradicate tumors. CD133 has been identified as an important cell surface marker to enrich the stem-like population in various human tumors. To reveal the molecular machinery underlying the stem-like features in tumor cells, we analyzed a promoter of CD133 gene using human colon carcinoma Caco-2 and synovial sarcoma Fuji cells, which endogenously express CD133 gene. A reporter analysis revealed that P5 promoter, located far upstream in a human CD133 gene locus, exhibits the highest activity among the five putative promoters (P1 to P5). Deletion and mutation analysis identified two ETS binding sites in the P5 region as being essential for its promoter activity. Electrophoretic mobility shift assays demonstrated the specific binding between nuclear factors and the ETS binding sequence. Overexpression of dominant-negative forms of Ets2 and Elk1 resulted in the significant decrease of P5 activity. Furthermore, treatment of Fuji cells with a specific MEK/ERK inhibitor, U0126, also markedly decreased CD133 expression, but there was no significant effect in Caco-2 cells, suggesting cell type-specific regulation of CD133 expression. Instead, the side population, another hallmark of TSLCs, was dramatically diminished in Caco-2 cells by U0126. Finally, Ras-mediated oncogenic transformation in normal human astrocytes conferred the stem-like capability to form neurosphere-like colonies with the increase of CD133 mRNA expression. In conclusion, the Ras/ERK pathway at least in part contributes to the maintenance and the acquisition of stem-like hallmarks, although the extent of its contribution is varied in a cell type-specific manner. These findings could help our comprehensive understanding of tumor stemness, and also improve the development of eradicative therapies against human malignancies.
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影响因子：
8.4
作者：
Monzani, Elena;Facchetti, Floriana;La Porta, Caterina A. M.
通讯作者：
La Porta, Caterina A. M.
影响因子：
64.8
作者：
O'Brien, Catherine A.;Pollett, Aaron;Dick, John E.
通讯作者：
Dick, John E.
DOI：
10.1016/j.bbrc.2007.11.005
发表时间：
2008-01-18
影响因子：
3.1
作者：
Lee, Joong-Seob;Gil, Jung-Eun;Kim, Hyunggee
通讯作者：
Kim, Hyunggee
影响因子：
11.2
作者：
Collins, AT;Berry, PA;Maitland, NJ
通讯作者：
Maitland, NJ
DOI：
10.1073/pnas.0307618100
发表时间：
2004-01-20
影响因子：
11.1
作者：
Kondo, T;Setoguchi, T;Taga, T
通讯作者：
Taga, T