Systems biological analysis of mitochondrial apoptosis synergies evoked by 2nd generation TRAIL receptor agonists and cardic glycosides

TRAIL受体激动剂是一种肿瘤细胞选择性药物，通过激活BH3-Only蛋白BID来触发线粒体凋亡，但到目前为止临床疗效有限。我们发现，与治疗相关的心脏糖苷(CGs)的无毒浓度，如洋地黄毒素，可引起复杂的凋亡蛋白数量变化，并通过线粒体Bcl2家族依赖的途径协同促进细胞死亡。在这里，我们将使用综合实验和数学分析的系统生物学方法来研究这些过程。我们将开发原型工具，用于预测结直肠癌(CRC)细胞系和活体模型中使用高级第二代TRAIL受体激动剂(IZI1551)和CGs联合治疗的病例特异性应答。为此，我们将(I)研究在CG暴露下控制TRAIL和Bcl-2家族信号的信号网络的定量组成的变化，(Ii)研究哪些信号级联驱动CG诱导的凋亡蛋白的去调控，(Iii)使用数学途径模型来预测这些变化将对凋亡信号转导产生的后果并确定最佳的治疗方案，以及(Iv)通过流式细胞仪和细胞内的显微实时测量以及体内的CRC异种移植模型来验证关于凋亡反应性的数学预测。除了对细胞凋亡信号转导和细胞死亡调控的复杂性有了详细的新见解外，本工作还将为进一步开发和利用IZI1551/CG共处理引起的线粒体凋亡协同效应提供基础，为未来的翻译研究奠定基础。

TRAIL receptor agonists are cancer cell-selective agents that trigger mitochondrial apoptosis through the activation of the BH3-only protein Bid, but so far demonstrated limited clinical efficacy. We found that non-toxic concentrations of therapeutically relevant cardiac glycosides (CGs), such as digitoxin, cause complex changes in apoptosis protein amounts and synergistically enhance cell death via the mitochondrial Bcl-2 family-dependent pathway. Here, we will investigate these processes, using a systems biological approach of integrated experimental and mathematical analyses. We will develop prototype tools for case-specifically predicting responsiveness to combination treatments with a superior 2nd generation TRAIL receptor agonist (IZI1551) and CGs in cell lines and in vivo models of colorectal cancer (CRC). To this end, we will (i) study changes in the quantitative composition of the signalling networks that control TRAIL and Bcl-2 family signalling in well characterised CRC model cell lines upon CG exposure, (ii) investigate which signalling cascades drive CG-induced apoptosis protein deregulation, (iii) employ mathematical pathway models to predict the consequences that these changes will have for apoptosis signal transduction and to identify optimal treatment schedules, and (iv) validate mathematical predictions on apoptosis responsiveness by flow-cytometric and microscopic real-time measurements in cellulo and by CRC xenograft models in vivo. Besides detailed novel insight into the complexity of apoptosis signal transduction and cell death regulation, this work will also provide the basis for the optimal further development and exploitation of mitochondrial apoptosis synergies evoked by IZI1551/CG co-treatments for future translational studies.