Description:
<jats:title>Abstract</jats:title>
<jats:p>Pulmonary microvascular endothelial cells are critically involved in development of radiation-induced acute inflammation and late fibrosis often limiting the delivery of sufficient dose to optimally treat lung cancer. Moreover, tumor-endothelium communication has emerged as a key target to augment radiotherapy by resensitizing endothelial-specific survival signals. Therefore, we aimed to employ high-throughput genome-wide gene expression and whole proteome analysis to uncover the molecular mechanisms governing tumor-vessel communication and radiation-induced normal tissue toxicity.</jats:p>
<jats:p>Human primary isolated pulmonary microvascular endothelial cells (HPMEC) were irradiated with 0 or 6Gy. Cells were harvested two hours (acute) and six days (late) after irradiation and proteins as well as RNA were extracted. Gene expression analysis was performed using 47k Illumina microarray (HumanHT-12 v4) platform. Mass spectrometry on an LTQ-Orbitrap instrument was employed for protein identification and relative quantification using label-free quantification techniques. An IMAC/TiO2 enrichment step to obtain phosphorylated peptides was carried out and analyzed by mass spectrometry as well. The regulation of candidate radiation-regulated genes and proteins were confirmed in-vitro and in irradiated lung specimen (C57BL/6 mouse) by real-time qRT-PCR, western blot and ELISA.</jats:p>
<jats:p>At the early timepoint a strong induction of genes involved in apoptosis and DNA-damage response such as GADD45A, PARP3 and DDB2 was identified. In contrast to the acute radiation response, cell adhesion (Integrins), pro-inflammatory (Interleukines), pro-angiogenic and matrix-remodeling related genes (MMPs, PDGFs, VEGFs) were induced late after irradiation. Integrative analysis of protein quantification, phosphorylation and gene-expression further revealed novel insights to an intricate gene/protein regulatory network underlying late radiation response in microvascular endothelium. The here identified genes and proteins involved in late radiation response constitute attractive targets for modulation of radiotherapy effects in tumor-endothelium or prevention of undesired radiotherapy-induced late side effects.</jats:p>
<jats:p>Citation Format: Tilmann Rackwitz, Philipp Seidel, Martin Winter, Cheng Zhou, Ramona Mayer, Uwe Warnken, Peter Hofner, Jürgen Debus, Martina Schnölzer, Amir Abdollahi. Integrative analysis of acute and late radiotherapy effects using genome-wide transcriptomics and quantitative proteomics. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3950. doi:10.1158/1538-7445.AM2014-3950</jats:p>