The oncogenic microRNA-27a targets genes that regulate specificity protein transcription factors and the G2-M checkpoint in MDA-MB-231 breast cancer cells
The oncogenic microRNA-27a targets genes that regulate specificity protein transcription factors and the G2-M checkpoint in MDA-MB-231 breast cancer cells
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DOI：
10.1158/0008-5472.can-07-2416
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发表时间：
2007-11-15
期刊：
影响因子：
11.2
通讯作者：
Safe, Stephen
中科院分区：
文献类型：
--
作者：
Mertens-Talcott, Susanne U.;Chintharlapalli, Sudhakar;Safe, Stephen
有证据表明，特异性蛋白 (Sp)，例如 Sp1、Sp3 和 Sp4，在肿瘤中过度表达，并有助于与癌细胞相关的增殖和血管生成表型。 Sp1、Sp3 和 Sp4 在一组雌激素受体 (ER) 阳性和 ER 阴性乳腺癌细胞系中表达，我们假设它们的表达调节可能是由于 microRNA-27a (miR-27a)，它也在这些细胞系中表达，并已被报道调节锌指 ZBTB10 基因（一种推定的 Sp 阻遏物）。用反义 miR-27a (as-miR-27a) 转染 ER 阴性 MDA-MB-231 乳腺癌细胞，导致 ZBTB10 mRNA 表达增加，mRNA 和蛋白质水平上 Sp1、Sp3 和 Sp4 表达减少，并且用含有 Sp1 和 Sp3 启动子插入片段的构建体转染的细胞活性也降低。此外，这些反应还伴随着 Sp 依赖性生存和血管生成基因表达的减少，包括生存素、血管内皮生长因子 (VEGF) 和 VEGF 受体 I (VEGFR1)。此外，在用ZBTB10表达质粒转染的MDA-MB-231细胞中观察到类似的结果。 as-miR-27a 和 ZBTB10 过表达均降低了处于细胞周期 S 期的 MDA-MB-231 细胞的百分比；然而，ZBTB10 增加了 G(0)-G(1) 中的细胞百分比，而 as-miR-27a 增加了 G(2)-M 中的细胞百分比。后一种反应与 Myt-1（另一个 miR-27a 靶基因）的诱导有关，Myt-1 通过增强磷酸化和 cdc2 失活来抑制 G2-M。因此，MDA-MB-231 细胞中 miR-27a 的致癌活性部分归因于 ZBTB10 和 Myt-1 的抑制。
There is evidence that specificity proteins (Sp), such as Sp1, Sp3, and Sp4, are overexpressed in tumors and contribute to the proliferative and angiogenic phenotype associated with cancer cells. Sp1, Sp3, and Sp4 are expressed in a panel of estrogen receptor (ER)-positive and ER-negative breast cancer cell lines, and we hypothesized that regulation of their expression may be due to microRNA-27a (miR-27a), which is also expressed in these cell lines and has been reported to regulate the zinc finger ZBTB10 gene, a putative Sp repressor. Transfection of ER-negative MDA-MB-231 breast cancer cells with antisense miR-27a (as-miR-27a) resulted in increased expression of ZBTB10 mRNA and decreased expression of Sp1, Sp3, and Sp4 at the mRNA and protein levels and also decreased activity in cells transfected with constructs containing Sp1 and Sp3 promoter inserts. In addition, these responses were accompanied by decreased expression of Sp-dependent survival and angiogenic genes, including survivin, vascular endothelial growth factor (VEGF), and VEGF receptor I (VEGFR1). Moreover, similar results were observed in MDA-MB-231 cells transfected with ZBTB10 expression plasmid. Both as-miR-27a and ZBTB10 overexpression decreased the percentage of MDA-MB-231 cells in S phase of the cell cycle; however, ZBTB10 increased the percentage of cells in G(0)-G(1), whereas as-miR-27a increased the percentage in G(2)-M. This latter response was associated with induction of Myt-1 (another miR-27a target gene), which inhibits G2-M through enhanced phosphorylation and inactivation of cdc2. Thus, the oncogenic activity of miR-27a in MDA-MB-231 cells is due, in part, to suppression of ZBTB10 and Myt-1.