Dose-dependent induction of distinct phenotypic responses to Notch pathway activation in mammary epithelial cells
Dose-dependent induction of distinct phenotypic responses to Notch pathway activation in mammary epithelial cells
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DOI：
10.1073/pnas.1000896107
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发表时间：
2010-03-16
影响因子：
11.1
通讯作者：
Brugge, Joan S.
中科院分区：
文献类型：
--
作者：
Mazzone, Marco;Selfors, Laura M.;Brugge, Joan S.
Notch受体的异常激活与乳腺癌有关;然而，导致Notch依赖性转化的机制仍然难以捉摸，因为Notch显示出二分的功能活性，促进增殖和生长停滞。我们研究了MCF-10A乳腺上皮细胞3D培养物中Notch通路激活的异质性反应的细胞基础。发现组成型活性Notch-1胞内结构域（NICD）的表达诱导两种不同类型的3D结构：大的过度增殖结构和小的生长停滞结构，细胞与基质的粘附减少。有趣的是，我们发现这些异质性表型反映了Notch途径激活水平的差异;高Notch活性导致多个基质粘附基因的下调和增殖抑制，而低Notch活性维持基质粘附并引起强烈的过度增殖反应。此外，微阵列分析暗示NICD诱导的p63下调基质粘附的损失。此外，基于反相蛋白阵列的分析和随后的功能丧失研究将STAT 3鉴定为NICD诱导的生长的主要下游介质。这些结果表明，对Notch的表型反应由途径激活的剂量决定;并且该剂量影响生长刺激和生长抑制效应之间的平衡。Notch信号传导的这种独特特征提供了对Notch在发育和肿瘤发生期间的二分效应的机制的见解。
Aberrant activation of Notch receptors has been implicated in breast cancer; however, the mechanisms contributing to Notch-dependent transformation remain elusive because Notch displays dichotomous functional activities, promoting both proliferation and growth arrest. We investigated the cellular basis for the heterogeneous responses to Notch pathway activation in 3D cultures of MCF-10A mammary epithelial cells. Expression of a constitutively active Notch-1 intracellular domain (NICD) was found to induce two distinct types of 3D structures: large, hyperproliferative structures and small, growth-arrested structures with reduced cell-to-matrix adhesion. Interestingly, we found that these heterogeneous phenotypes reflect differences in Notch pathway activation levels; high Notch activity caused down-regulation of multiple matrix-adhesion genes and inhibition of proliferation, whereas low Notch activity maintained matrix adhesion and provoked a strong hyperproliferative response. Moreover, microarray analyses implicated NICD-induced p63 down-regulation in loss of matrix adhesion. In addition, a reverse-phase protein array-based analysis and subsequent loss-of-function studies identified STAT3 as a dominant downstream mediator of the NICD-induced outgrowth. These results indicate that the phenotypic responses to Notch are determined by the dose of pathway activation; and this dose affects the balance between growth-stimulative and growth-suppressive effects. This unique feature of Notch signaling provides insights into mechanisms that contribute to the dichotomous effects of Notch during development and tumorigenesis.