Double-stranded RNA-binding protein regulates vascular endothelial growth factor mRNA stability, translation, and breast cancer angiogenesis
Double-stranded RNA-binding protein regulates vascular endothelial growth factor mRNA stability, translation, and breast cancer angiogenesis
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DOI：
10.1128/mcb.02078-06
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发表时间：
2008-01-01
影响因子：
5.3
通讯作者：
Claffey, Kevin P.
中科院分区：
文献类型：
--
作者：
Vumbaca, Frank;Phoenix, Kathryn N.;Claffey, Kevin P.
血管内皮生长因子(VEGF)是一种重要的血管生成因子，在大多数实体肿瘤中是在营养和氧气受限的条件下表达的。在低氧条件下，血管内皮生长因子的表达需要通过激活的低氧诱导因子1(HIF-1)进行转录，增加mRNA的稳定性，促进翻译。本研究发现DRBP家族的特异性亚型双链RNA结合蛋白76/NF90(DRBP76/NF90)是一种在低氧条件下对血管内皮生长因子mRNA的稳定性和蛋白质合成起关键作用的血管内皮生长因子信使核糖核酸结合蛋白。DRBP76/NF90蛋白与人VEGF3‘未翻译的mRNA稳定元件结合。针对DRBP76/NF90异构体的RNA干扰可在不改变HIF-1依赖的转录活性的情况下限制低氧诱导的VEGFmRNA和蛋白的表达。DRBP76/NF90在MDA-MB-435乳腺癌细胞中的稳定抑制显示，在低氧条件下，多聚体相关的VEGF mRNA水平降低，mRNA稳定性降低。DRBP76/NF90蛋白的瞬时过表达增加了常氧和低氧条件下合成的血管内皮生长因子的mRNA和蛋白水平。在原位乳腺肿瘤模型中，稳定抑制DRBP76/NF90亚型的细胞显示出降低的致瘤和血管生成潜力。这些数据表明，DRBP76/NF90亚型通过促进VEGF mRNA在低氧条件下负载到多聚体上并进行翻译来促进VEGF的表达，从而促进乳腺癌的生长和体内血管生成。
Vascular endothelial growth factor (VEGF) is a key angiogenic factor expressed under restricted nutrient and oxygen conditions in most solid tumors. The expression of VEGF under hypoxic conditions requires transcription through activated hypoxia-inducible factor 1 (HIF-1), increased mRNA stability, and facilitated translation. This study identified double-stranded RNA-binding protein 76/NF90 (DRBP76/NF90), a specific isoform of the DRBP family, as a VEGF mRNA-binding protein which plays a key role in VEGF mRNA stability and protein synthesis under hypoxia. The DRBP76/NF90 protein binds to a human VEGF 3' untranslated mRNA stability element. RNA interference targeting the DRBP76/NF90 isoform limited hypoxia-inducible VEGF mRNA and protein expression with no change in HIF-1-dependent transcriptional activity. Stable repression of DRBP76/NF90 in MDA-MB-435 breast cancer cells demonstrated reduced polysome-associated VEGF mRNA levels under hypoxic conditions and reduced mRNA stability. Transient overexpression of the DRBP76/NF90 protein increased both VEGF mRNA and protein levels synthesized under normoxic and hypoxic conditions. Cells with stable repression of the DRBP76/NF90 isoform showed reduced tumorigenic and angiogenic potential in an orthotopic breast tumor model. These data demonstrate that the DRBP76/NF90 isoform facilitates VEGF expression by promoting VEGF mRNA loading onto polysomes and translation under hypoxic conditions, thus promoting breast cancer growth and angiogenesis in vivo.