Towards a predictive and deterministic understanding of transmitotic cell fates during TRAIL-induced cell death signalling

细胞增殖和细胞死亡之间的微妙平衡是许多生理过程的基础，其失调与癌症的发展有关。程序性细胞死亡，如细胞凋亡，可以由与细胞表面死亡受体结合的配体触发。我们最近发现，细胞周期进程调节癌细胞对TRAIL诱导的凋亡的易感性：有趣的是，大量通过有丝分裂的细胞遭受亚致死性凋亡DNA损伤，并最终逃离外源性凋亡。然而，在这种情况下，目前无法预测同基因群体中单个细胞的命运（死亡与逃逸/存活）。目前，我们对在这种情况下如何以及何时（预先）确定肿瘤坏死因子相关凋亡诱导配体治疗后的细胞命运缺乏了解。此外，我们目前不知道定量和动力学Mcl-1，主要的Bcl-2家族成员，赋予传递凋亡抗性，是如何通过有丝分裂正常进展后降解，以重新建立凋亡易感性。我们将通过详细的定量和动力学研究以及系统生物学方法来处理这些重要的开放问题，利用我们的创新工具来并行监测细胞周期进程和细胞死亡信号。此外，我们将验证在更复杂的细胞生长情况下，包括实验上可控的3D球状体和体内环境中，可以观察到对TRAIL诱导的细胞凋亡的传递抵抗或逃逸的程度。外源性细胞凋亡将由一个优越的上级第二代和与肿瘤相关的六聚体TRAIL变体触发，增加了研究计划的应用相关性。已经收集了大量非常有前途的数据，支持我们的研究目标。总的来说，我们相信，计划的工作将使我们能够从描述和观察过渡到预测和确定性的理解细胞命运的决定，在相互作用的外源性诱导的细胞死亡信号和细胞周期进程。我们的工作解决了一个目前很大程度上未研究但有影响力的主题，该主题与理解细胞死亡调节和逃逸的关键方面高度相关。

A subtle balance between cell proliferation and cell death is fundamental for many physiological processes and its dysregulation is implicated in the development of cancer. Programmed cell death, such as apoptosis, can be triggered by ligands that bind to cell-surface death receptors. We recently found that cell cycle progression modulates the susceptibility to TRAIL-induced apoptosis in cancer cells: Interestingly, substantial numbers of cells that progress through mitosis suffer sublethal apoptotic DNA damage and ultimately escape from extrinsic apoptosis. However, the fate (death vs. escape/survival) of individual cells within isogenic populations in this scenario currently cannot be predicted. At the present time, we lack an understanding for how and when cell fates are (pre-)determined following TRAIL treatment in this context. Additionally, we currently do not know quantitatively and kinetically how Mcl-1, the major Bcl-2 family member that confers transmitotic apoptosis resistance, is degraded after normal progression through mitosis to re-establish apoptosis susceptibility. We will approach these important open questions by detailed quantitative and kinetic studies and by systems biological approaches, taking advantage of our innovative tools to monitor cell cycle progression and cell death signalling in parallel. In addition, we will validate to which extent transmitotic resistance to or escape from TRAIL-induced apoptosis can be observed in more complex cell growth scenarios, including experimentally well controllable 3D spheroids and in vivo settings. Extrinsic apoptosis will be triggered by a superior 2nd generation and translationally relevant hexameric TRAIL variant, increasing the application relevance of the research programme. Substantial amounts of highly promising data have been collected that support our research objectives. Overall, we are convinced that the planned work will allow us to transition from description and observation towards a predictive and deterministic understanding of cell fate decision making in the interplay of extrinsically induced cell death signalling and cell cycle progression. Our work addresses a currently largely unstudied but impactful topic that is highly relevant for understanding a crucial facet of cell death-regulation and –escape.