MiR-192-Mediated Positive Feedback Loop Controls the Robustness of Stress-Induced p53 Oscillations in Breast Cancer Cells.
MiR-192-Mediated Positive Feedback Loop Controls the Robustness of Stress-Induced p53 Oscillations in Breast Cancer Cells.
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DOI：
10.1371/journal.pcbi.1004653
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发表时间：
2015-12
影响因子：
4.3
通讯作者：
Ma L
中科院分区：
文献类型：
--
作者：
Moore R;Ooi HK;Kang T;Bleris L;Ma L
p53 肿瘤抑制蛋白在细胞应激和癌症预防中发挥着关键作用。许多转录后调节因子（称为 microRNA）与 p53 介导的细胞网络密切相关。虽然 p53 和 microRNA 之间的分子相互作用已经出现，但对调节机制以及 microRNA 与 p53 核心形成反馈环的作用的系统级理解仍然难以捉摸。在这里，我们从文献中发现，存在三类围绕p53的microRNA介导的反馈环路，它们都具有正反馈的性质。为了探索 p53 的细胞性能与 microRNA 反馈途径之间的关系，我们开发了核心 p53-MDM2 模块的数学模型，该模型与涉及 miR-192、miR-34a 和 miR-29a 的三个 microRNA 介导的正反馈环相结合。与外在噪声相关的模拟和分叉分析再现了单细胞中 DNA 损伤下 p53 的振荡行为，并且值得注意的是，当考虑到普遍存在的细胞间变异性时，特定的 microRNA 废除可以破坏野生型细胞表型。为了评估这些计算机结果，我们在 MCF7 乳腺癌细胞中进行了 microRNA 扰动实验。通过延时显微镜观察细胞群对 DNA 双链断裂的反应，以及对群体中单细胞表型的图像分类，证实细胞 p53 振荡在 miR-192 扰动后受到损害，与模型预测相匹配。我们的研究通过建模与定量实验相结合，为 microRNA 介导的正反馈环路在赋予 p53 应激诱导反应的系统性能稳健性方面的作用提供了新的证据。 DNA 损伤引发的肿瘤抑制蛋白 p53 的活性可能是显着动态的。 p53 振荡在癌症发展过程中细胞决策中的功能作用已得到认可。最近的一系列研究揭示了 p53 网络和 microRNA 之间的广泛串扰，但 microRNA 参与 p53 信号通路调节的具体细节仍然很大程度上难以捉摸。在这里，我们研究了与 p53 形成反馈调节的 microRNA。我们列举了这些 microRNA 和 p53 核心之间的分子相互作用，并开发了一个数学模型来重现单细胞中 DNA 损伤诱导的 p53 振荡。我们结合实验评估进行了计算机模拟和系统分析，以探究 p53 在 microRNA 抑制条件下的行为。我们发现乳腺癌细胞系中 p53 应激反应的强大细胞性能是由 miR-192 控制的，miR-192 与 p53 形成正反馈环。
The p53 tumor suppressor protein plays a critical role in cellular stress and cancer prevention. A number of post-transcriptional regulators, termed microRNAs, are closely connected with the p53-mediated cellular networks. While the molecular interactions among p53 and microRNAs have emerged, a systems-level understanding of the regulatory mechanism and the role of microRNAs-forming feedback loops with the p53 core remains elusive. Here we have identified from literature that there exist three classes of microRNA-mediated feedback loops revolving around p53, all with the nature of positive feedback coincidentally. To explore the relationship between the cellular performance of p53 with the microRNA feedback pathways, we developed a mathematical model of the core p53-MDM2 module coupled with three microRNA-mediated positive feedback loops involving miR-192, miR-34a, and miR-29a. Simulations and bifurcation analysis in relationship to extrinsic noise reproduce the oscillatory behavior of p53 under DNA damage in single cells, and notably show that specific microRNA abrogation can disrupt the wild-type cellular phenotype when the ubiquitous cell-to-cell variability is taken into account. To assess these in silico results we conducted microRNA-perturbation experiments in MCF7 breast cancer cells. Time-lapse microscopy of cell-population behavior in response to DNA double-strand breaks, together with image classification of single-cell phenotypes across a population, confirmed that the cellular p53 oscillations are compromised after miR-192 perturbations, matching well with the model predictions. Our study via modeling in combination with quantitative experiments provides new evidence on the role of microRNA-mediated positive feedback loops in conferring robustness to the system performance of stress-induced response of p53. DNA damage triggered activities of the tumor suppressor protein p53 could be significantly dynamical. The functional role of p53 oscillations in cellular decision making during cancer development has been appreciated. A set of recent studies have revealed extensive crosstalk between the p53 network and microRNAs, but the specifics of the participation of microRNAs in the regulation of the p53 signaling pathway remains largely elusive. Here we investigated microRNAs that form feedback regulation with p53. We enumerated the molecular interactions among these microRNAs and the p53 core and developed a mathematical model to reproduce the DNA damage induced p53 oscillations in single cells. We performed computer simulations and system analysis in combination with experimental assessment to probe the behavior of p53 under microRNA-inhibited conditions. We show that the robust cellular performance of the stress response of p53 in a breast cancer cell line is controlled by miR-192, which forms positive feedback loops with p53.