Winkler Juliane, Roessler Stephanie, Sticht Carsten, DiGuilio Amanda L, Drucker Elisabeth, Holzer Kerstin, Eiteneuer Eva, Herpel Esther, Breuhahn Kai, Gretz Norbert, Schirmacher Peter, Ori Alessandro, Singer Stephan
Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany.
Medical Research Centre, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.
Oncotarget. 2016 Apr 19;7(16):22883-92. doi: 10.18632/oncotarget.8256.
Importins and exportins represent an integral part of the nucleocytoplasmic transport machinery with fundamental importance for eukaryotic cell function. A variety of malignancies including hepatocellular carcinoma (HCC) show de-regulation of nuclear transport factors such as overexpression of the exportin Cellular Apoptosis Susceptibility (CAS). The functional implications of CAS in hepatocarcinogenesis remain, however, poorly understood. Here we integrated proteomics, transcriptomics and functional assays with patient data to further characterize the role of CAS in HCC. By analyzing ~ 1700 proteins using quantitative mass spectrometry in HCC cells we found that CAS depletion by RNAi leads to de-regulation of integrins, particularly down-regulation of integrin β1. Consistent with this finding, CAS knockdown resulted in substantially reduced migration and invasion of HCC cell lines as analyzed by 2D 'scratch' and invasion chamber assays, respectively. Supporting the potential in vivo relevance, high expression levels of CAS in HCC tissue samples were associated with macroangioinvasion and poorer patient outcome. Our data suggest a previously unanticipated link between CAS and integrin signaling which correlates with an aggressive HCC phenotype.
输入蛋白和输出蛋白是核质运输机制不可或缺的一部分，对真核细胞功能至关重要。包括肝细胞癌（HCC）在内的多种恶性肿瘤显示出核运输因子的失调，如输出蛋白细胞凋亡敏感性蛋白（CAS）的过表达。然而，CAS在肝癌发生中的功能意义仍知之甚少。在此，我们将蛋白质组学、转录组学和功能分析与患者数据相结合，以进一步阐明CAS在HCC中的作用。通过在HCC细胞中使用定量质谱分析约1700种蛋白质，我们发现RNA干扰介导的CAS缺失导致整合素失调，尤其是整合素β1的下调。与此发现一致，分别通过二维“划痕”和侵袭小室试验分析，CAS敲低导致HCC细胞系的迁移和侵袭显著减少。支持其潜在的体内相关性，HCC组织样本中CAS的高表达水平与大血管侵犯和患者预后较差相关。我们的数据表明，CAS与整合素信号传导之间存在先前未预料到的联系，这与侵袭性HCC表型相关。
