Influence of tumor-specific epigenetic aberrations on platin resistance of ovarian cancer

卵巢癌患者的低存活率是由于错过了筛查机会，以及尽管一线治疗后应答率很高，但仍经常出现铂耐药。只有临床参数被确定为预后标记物，而没有已知的预测性标记物。该项目将收集数据以实现翻译和基本的科学目标。翻译部分将验证已经确定的II型上皮性卵巢癌预后和预测甲基化标志物，并建立新的标志物组合。受影响的表观基因将在项目的第二部分进行功能分析-旨在澄清前一个项目中确定的三个方面：(1)是什么机制导致RUNX3蛋白异构体在铂耐药和致癌特性方面的不同功能？全基因组ChIP-Seq和基因表达分析结合蛋白质-蛋白质相互作用图谱将确定依赖于异构体的转录及其调控。(2)TRIB2-a基因影响哪些DNA修复系统，介导DNA加合物积累、G2-M细胞周期停滞、细胞凋亡和顺铂敏感性。特定的环境刺激和处理将激活和调节DNA修复通路，并使识别TRIB2效应成为可能。(3)哪些影响具有与钙相关的信号通路及其对铂耐药的调制？我们已经确定了几种钙依赖蛋白，它们在存活时间较短的患者或对铂耐药的细胞中高度甲基化。在顺铂处理下，敏感细胞和耐药细胞中的细胞内钙离子水平的测量以及特定的钙离子流量调节的影响将得以实现。此外，使用的模型系统将进行优化，以提高与体内情况的可比性。除了阐明分子耐药机制外，所获得的数据还将有助于确定使细胞对铂重新敏感的策略，潜在地调节未来对铂化疗的长期反应。

Low survival rates of ovarian cancer patients are caused by missing screening opportunities and a frequent development of platin resistance despite high response rates after first-line treatment. Only clinical parameters are established as prognostic markers and no predictive markers are known. This project will gather data to realize both translational and basic scientific aims. The translational part will validate already identified prognostic and predictive methylation markers for type-II epithelial ovarian cancer and establish new marker combinations. Affected, epigenetically deregulated genes will be functionally analyzed in the second part of the project – aiming to clarify 3 aspects identified in the previous project:(1) Which mechanisms cause the different functions of RUNX3 protein isoforms regarding platin resistance and oncogenic properties? Genome wide ChIP-Seq and gene expression analyses combined with protein-protein interaction mapping will identify isoform-dependent transcriptomes and their regulation.(2) Which DNA repair-systems are affected by TRIB2 – a gene mediating DNA adduct accumulation, G2-M cell cycle arrest, apoptosis and cisplatin sensitivity. Specific environmental stimuli and treatments will activate and modulate DNA repair pathways and enable the identification of TRIB2 effects.(3) Which impacts have Ca2+-associated signaling pathways and their modulation on platin resistance? We have identified several Ca2+-dependent proteins which are hypermethylated in patients with short survival or in platin resistant cells. Measurements of cellular Ca2+-levels in sensitive and resistant cells under cisplatin treatment and the determination of the influence of specific modulations of Ca2+-fluxes will be realized. Moreover, used model systems will be optimized to improve the comparability to the in-vivo situation. Additional to the elucidation of molecular resistance mechanisms the obtained data will enable the identification of strategies to re-sensitize cells to platin potentially modulating the long-term response to platin chemotherapy in the future.