Loss of von Hippel-Lindau protein causes cell density dependent deregulation of CyclinD1 expression through Hypoxia-inducible factor
Loss of von Hippel-Lindau protein causes cell density dependent deregulation of CyclinD1 expression through Hypoxia-inducible factor
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DOI：
10.1038/sj.onc.1206373
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发表时间：
2003-05-08
期刊：
影响因子：
8
通讯作者：
Ohno, S
中科院分区：
文献类型：
--
作者：
Baba, M;Hirai, S;Ohno, S
von Hippel-Lindau 基因 (VHL) 表达的缺失会导致细胞生长的接触抑制失调，这可能是 VHL 肿瘤抑制功能的基础之一。在这里，我们表明 VHL 基因产物 (pVHL) 的这种功能取决于细胞自主事件。为了鉴定直接参与接触抑制的 pVHL 靶基因，我们比较了 VHL 缺陷的肾癌 786-O 细胞和感染编码 VHL 的腺病毒载体的细胞之间的基因表达谱。除了已知的 pVHL 调节基因（例如血管内皮生长因子和碳酸酐酶）外，我们还发现 cyclinD1 作为高细胞密度下 pVHL 的新靶标。在表达VHL的细胞（VHL（+）细胞）中，cyclinD1 mRNA表达水平在高细胞密度下降低，而在VHL缺陷细胞（VHL（-）细胞）中则保持在相对较高的水平。在高细胞密度的 VHL (-) 细胞中，cyclinD1 表达水平也异常高。因此，这些细胞中视网膜母细胞瘤（Rb）蛋白的磷酸化水平仍然很高，而在接触抑制下的VHL（+）细胞中没有磷酸化的Rb。即使在缺氧状态下的VHL(+)细胞中，也观察到高细胞密度下cyctinD1的异常表达。此外，对 pVHL 介导的蛋白水解具有抗性的 HIF 突变体的异位表达会导致 VHL (+) 细胞中的 cyclinD1 表达异常。综上所述，这些观察结果表明 VHL 是通过 HIF 在高细胞密度下下调 cyclinD1 所必需的。
Loss of the von Hippel-Lindau gene (VHL) expression causes deregulation of contact inhibition of cell growth, which might be one of the bases of the tumor suppressor function of VHL. Here we show that this function of the VHL gene product (pVHL) depends on cell autonomous events. To identify the target gene of pVHL, which is directly involved in the contact inhibition, we compared the gene expression profile between VHL-deficient renal carcinoma 786-O cells and those infected with an adenovirus vector encoding VHL. In addition to known pVHL-regulated genes, such as vascular endothelial growth factor and carbonic anhydrase, we found cyclinD1 as a new target of pVHL at a high cell density. In VHL-expressing cells (VHL (+) cells), the cyclinD1 mRNA expression level diminishes at a high cell density, while it remains at a relatively high level in VHL-deficient cells (VHL (-) cells). The cyclinD1 expression level was also abnormally high in VHL (-) cells at a high cell density. Consequently, the phosporylation level of the retinoblastoma (Rb) protein remained high in these cells, whereas there was no phosporylated Rb in VHL (+) cells under the contact inhibition. The abnormal expression of cyctinD1 at a high cell density was observed even in VHL (+) cells under the hypoxic state. Moreover, ectopic expression of a HIF mutant resistant to pVHL-mediated proteolysis causes the abnormal cyclinD1 expression in VHL (+) cells. Taken together, these observations indicate that VHL is required for the downregulation of cyclinD1 at a high cell density through HIF.