The subcellular localization of IGFBP5 affects its cell growth and migration functions in breast cancer.
The subcellular localization of IGFBP5 affects its cell growth and migration functions in breast cancer.
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DOI：
10.1186/1471-2407-9-103
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发表时间：
2009-04-03
期刊：
影响因子：
3.8
通讯作者：
Zhang W
中科院分区：
文献类型：
--
作者：
Akkiprik M;Hu L;Sahin A;Hao X;Zhang W
临床标志物研究显示胰岛素样生长因子结合蛋白 5 (IGFBP5) 与乳腺癌转移相关。然而，理解 IGFBP5 如何发挥这种能力的一个主要困难是矛盾的观察，即乳腺癌细胞系中 IGFBP5 的异位过度表达导致细胞增殖受到抑制。在癌组织中，IGFBP5主要存在于细胞质中；然而，在转染的细胞中，IGFBP5主要位于细胞核中。我们假设 IGFBP5 的亚细胞定位影响其在宿主细胞中的功能。为了检验这一假设，我们生成了野生型和突变型 IGFBP5 表达构建体。该突变发生在蛋白质的核定位序列 (NLS) 内，并使用野生型 IGFBP5 表达构建体作为模板通过定点诱变产生。接下来，我们将每个表达构建体转染到 MDA-MB-435 乳腺癌细胞中，以建立过表达野生型或突变型 IGFBP5 的稳定克隆。功能分析显示，过表达野生型IGFBP5的细胞比载体转染的细胞具有显着更低的细胞生长速率和运动性，而过表达突变型IGFBP5的细胞表现出显着更高的增殖和迁移能力。为了说明蛋白质的亚细胞定位，我们生成了野生型和突变型 IGFBP5-pDsRed 荧光融合构建体。荧光显微镜成像显示，IGFBP5 中 NLS 的突变将 IGFBP5 的积累从蛋白质的细胞核转移到细胞质。总之，这些发现表明IGFBP5的突变形式增加了乳腺癌细胞的增殖和运动性，并且IGFBP5中的NLS突变导致IGFBP5定位在细胞质中，这表明IGFBP5的亚细胞定位影响其在乳腺癌细胞中的细胞生长和迁移功能。
Insulin-like growth factor binding protein 5 (IGFBP5) has been shown to be associated with breast cancer metastasis in clinical marker studies. However, a major difficulty in understanding how IGFBP5 functions in this capacity is the paradoxical observation that ectopic overexpression of IGFBP5 in breast cancer cell lines results in suppressed cellular proliferation. In cancer tissues, IGFBP5 resides mainly in the cytoplasm; however, in transfected cells, IGFBP5 is mainly located in the nucleus. We hypothesized that subcellular localization of IGFBP5 affects its functions in host cells. To test this hypothesis, we generated wild-type and mutant IGFBP5 expression constructs. The mutation occurs within the nuclear localization sequence (NLS) of the protein and is generated by site-directed mutagenesis using the wild-type IGFBP5 expression construct as a template. Next, we transfected each expression construct into MDA-MB-435 breast cancer cells to establish stable clones overexpressing either wild-type or mutant IGFBP5. Functional analysis revealed that cells overexpressing wild-type IGFBP5 had significantly lower cell growth rate and motility than the vector-transfected cells, whereas cells overexpressing mutant IGFBP5 demonstrated a significantly higher ability to proliferate and migrate. To illustrate the subcellular localization of the proteins, we generated wild-type and mutant IGFBP5-pDsRed fluorescence fusion constructs. Fluorescence microscopy imaging revealed that mutation of the NLS in IGFBP5 switched the accumulation of IGFBP5 from the nucleus to the cytoplasm of the protein. Together, these findings imply that the mutant form of IGFBP5 increases proliferation and motility of breast cancer cells and that mutation of the NLS in IGFBP5 results in localization of IGFBP5 in the cytoplasm, suggesting that subcellular localization of IGFBP5 affects its cell growth and migration functions in the breast cancer cells.
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DOI：
10.1186/bcr2116
发表时间：
2008
期刊：
Breast cancer research : BCR
影响因子：
--
作者：
Akkiprik M;Feng Y;Wang H;Chen K;Hu L;Sahin A;Krishnamurthy S;Ozer A;Hao X;Zhang W
通讯作者：
Zhang W
DOI：
10.1073/pnas.92.10.4407
发表时间：
1995-05-09
影响因子：
11.1
作者：
MOLL, UM;LAQUAGLIA, M;RIOU, G
通讯作者：
RIOU, G
DOI：
10.1016/s0006-291x(02)00570-3
发表时间：
2002-06-28
影响因子：
3.1
作者：
Perks, CM;McCaig, C;Holly, JMP
通讯作者：
Holly, JMP
影响因子：
21.3
作者：
Giannakakou, P;Sackett, DL;Fojo, T
通讯作者：
Fojo, T
DOI：
10.1083/jcb.150.3.433
发表时间：
2000-08-07
期刊：
The Journal of cell biology
影响因子：
--
作者：
Dundr M;Misteli T;Olson MO
通讯作者：
Olson MO