RAD9A promotes metastatic phenotypes through transcriptional regulation of anterior gradient 2 (AGR2)
RAD9A promotes metastatic phenotypes through transcriptional regulation of anterior gradient 2 (AGR2)
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DOI：
10.1093/carcin/bgy131
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发表时间：
2019-01-01
期刊：
影响因子：
4.7
通讯作者：
Lieberman, Howard B.
中科院分区：
文献类型：
--
作者：
Broustas, Constantinos G.;Hopkins, Kevin M.;Lieberman, Howard B.
RAD 9A在前列腺肿瘤发生和转移相关表型中起重要作用。该蛋白质典型地作为RAD 9A-HUS 1-RAD 1复合物的一部分起作用，但也可以独立地起作用。RAD 9A可以通过结合启动子中或附近的p53共有序列来选择性地反式激活多个基因，包括CDKN 1A和NEIL 1。RAD 9A在人前列腺癌标本和细胞系中过表达;其表达与肿瘤进展相关。在前列腺癌细胞中沉默RAD 9A削弱了它们在体内形成肿瘤和在体外独立迁移以及生长锚定的能力。我们在此证明，RAD 9A转录控制AGR 2，一种在转移性前列腺癌患者中异常过表达的基因。在PC-3细胞中短暂或稳定敲低RAD 9A导致AGR 2蛋白丰度下调。AGR 2蛋白水平降低是由于AGR 2 mRNA丰度降低。编码起始位点上游的AGR 2基因组区域含有几个p53共有序列。RAD 9A特异性结合于PC-3细胞中AGR 2的5 '非翻译区，在转录起始位点下游+3136位的部分p53共有序列处，通过染色质免疫沉淀，随后通过PCR扩增确定。RAD 9A与p53共有序列的结合足以驱动AGR 2基因转录，这通过荧光素酶报告基因测定显示。相反，当AGR 2上的RAD 9A结合序列突变时，没有检测到荧光素酶活性。敲低PC-3细胞中的RAD 9A会损害细胞迁移和锚定非依赖性生长。然而，在RAD 9A耗尽的PC-3细胞中异位表达的AGR 2恢复了这些表型。我们的结果表明，RAD 9A通过控制AGR 2丰度来驱动转移。
RAD9A plays an important role in prostate tumorigenesis and metastasis-related phenotypes. The protein classically functions as part of the RAD9A-HUS1-RAD1 complex but can also act independently. RAD9A can selectively transactivate multiple genes, including CDKN1A and NEIL1 by binding p53-consensus sequences in or near promoters. RAD9A is overexpressed in human prostate cancer specimens and cell lines; its expression correlates with tumor progression. Silencing RAD9A in prostate cancer cells impairs their ability to form tumors in vivo and migrate as well as grow anchorage independently in vitro. We demonstrate herein that RAD9A transcriptionally controls AGR2, a gene aberrantly overexpressed in patients with metastatic prostate cancer. Transient or stable knockdown of RAD9A in PC-3 cells caused downregulation of AGR2 protein abundance. Reduced AGR2 protein levels were due to lower abundance of AGR2 mRNA. The AGR2 genomic region upstream of the coding initiation site contains several p53 consensus sequences. RAD9A bound specifically to the 5'-untranslated region of AGR2 in PC-3 cells at a partial p53 consensus sequence at position +3136 downstream from the transcription start site, determined by chromatin immunoprecipitation, followed by PCR amplification. Binding of RAD9A to the p53 consensus sequence was sufficient to drive AGR2 gene transcription, shown by a luciferase reporter assay. In contrast, when the RAD9A-binding sequence on the AGR2 was mutated, no luciferase activity was detected. Knockdown of RAD9A in PC-3 cells impaired cell migration and anchorage-independent growth. However, ectopically expressed AGR2 in RAD9A-depleted PC-3 cells restored these phenotypes. Our results suggest RAD9A drives metastasis by controlling AGR2 abundance.