Defining NOTCH3 target genes in ovarian cancer.
Defining NOTCH3 target genes in ovarian cancer.
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DOI：
10.1158/0008-5472.can-11-2181
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发表时间：
2012-05-01
期刊：
影响因子：
11.2
通讯作者：
Wang TL
中科院分区：
文献类型：
--
作者：
Chen X;Thiaville MM;Chen L;Stoeck A;Xuan J;Gao M;Shih IeM;Wang TL
NOTCH3基因扩增在许多卵巢癌和乳腺癌的进展中起重要作用，但NOTCH3信号的靶点尚不清楚。在这里，我们报告了使用综合系统生物学方法来确定NOTCH3的直接靶基因。转录组分析显示，在卵巢癌和乳腺癌细胞中，NOTCH信号的抑制导致细胞周期调控和核苷酸代谢通路中基因的下调。ChIP-on-chip分析确定了NOTCH3/CSL转录复合物占用的启动子靶序列，除了规范的CSL结合基序外，还包括一个新的CSL结合基序（N1）。转录组和ChIP-on- ChIP数据的整合表明，ChIP靶基因与卵巢癌细胞中notch调控的转录组显著重叠。从鉴定的一组基因中，我们确定有丝分裂装置组织蛋白DLGAP5 （HURP/DLG7）是一个关键靶点。N1基序和典型的CSL结合基序都是激活DLGAP5转录所必需的。在癌细胞中沉默DLGAP5通过阻断G2/M期的细胞周期来抑制肿瘤的发生和细胞的增殖。相反，DLGAP5的强制表达部分抵消了药物或rnai介导的癌细胞抑制的生长抑制作用。我们的研究结果明确了NOTCH3的直接靶基因，并突出了DLGAP5在NOTCH3促肿瘤功能中的作用。
NOTCH3 gene amplification plays an important role in the progression of many ovarian and breast cancers, but the targets of NOTCH3 signaling are unclear. Here we report the use of an integrated systems biology approach to identify direct target genes for NOTCH3. Transcriptome analysis showed that suppression of NOTCH signaling in ovarian and breast cancer cells led to downregulation of genes in pathways involved in cell cycle regulation and nucleotide metabolism. ChIP-on-chip analysis defined promoter target sequences, including a new CSL binding motif (N1) in addition to the canonical CSL binding motif, that were occupied by the NOTCH3/CSL transcription complex. Integration of transcriptome and ChIP-on-chip data demonstrated that the ChIP target genes overlapped significantly with the NOTCH-regulated transcriptome in ovarian cancer cells. From the set of genes identified we determined that the mitotic apparatus organizing protein DLGAP5 (HURP/DLG7) was a critical target. Both the N1 motif and the canonical CSL binding motif were essential to activate DLGAP5 transcription. DLGAP5 silencing in cancer cells suppressed tumorigenicity and inhibited cellular proliferation by arresting the cell cycle at the G2/M phase. In contrast, enforced expression of DLGAP5 partially counteracted the growth inhibitory effects of a pharmacological or RNAi-mediated inhibition in cancer cells. Our findings define direct target genes of NOTCH3 and highlight DLGAP5 in the tumor-promoting function of NOTCH3.