Bendinelli Paola, Maroni Paola, Matteucci Emanuela, Luzzati Alessandro, Perrucchini Giuseppe, Desiderio Maria Alfonsina
Dipartimento di Scienze Biomediche per la Salute, Molecular Pathology Laboratory, Università degli Studi di Milano, Italy.
Istituto Ortopedico Galeazzi, IRCCS, Milano, Italy.
Biochim Biophys Acta. 2014 Apr;1843(4):815-26. doi: 10.1016/j.bbamcr.2013.12.015. Epub 2013 Dec 27.
The present study was undertaken to clarify the function(s) of Endothelin-1 and its receptors ETAR and ETBR in osteolytic-bone metastasis from breast cancer, and their regulation by hepatocyte and transforming growth factors (HGF, TGF-β) and hypoxia. The aim was to evaluate the adaptability of bone metastasis to microenvironmental stimuli through Endothelin-1-mediated epithelial-mesenchymal transition (EMT), or the reverse process MET, and through osteomimicry possible key features for bone colonization. We compared low (MCF-7) and high (MDA-MB231) invasive-breast carcinoma cells, and 1833-bone metastatic clone, with human pair-matched primary breast-carcinomas and bone metastases. Parental MDA-MB231 and the derived 1833-clone responded oppositely to the stimuli. In 1833 cells, TGF-β and hypoxia increased Endothelin-1 release, altogether reducing invasiveness important for engraftment, while Endothelin-1 enhanced MDA-MB231 cell invasiveness. The Endothelin-1-autocrine loop contributed to the cooperation of intracellular-signaling pathways and extracellular stimuli triggering MET in 1833 cells, and EMT in MDA-MB231 cells. Only in 1833 cells, HGF negatively influenced transactivation and release of Endothelin-1, suggesting a temporal sequence of these stimuli with an initial role of HGF-triggered Wnt/β-catenin pathway in metastatization. Then, Endothelin-1/ETAR conferred MET and osteomimetic phenotypes, with Runt-related transcription factor 2 activation and metalloproteinase 9 expression, contributing to colonization and osteolysis. Findings with human pair-matched primary ductal carcinomas and bone metastases gave a translational significance to the molecular study. Endothelin-1, ETAR and ETBR correlated with the acquisition of malignant potential, because of high expression already in the in situ carcinoma. These molecular markers might be used as predictive index of aggressive behavior and invasive/metastatic phenotype.
本研究旨在阐明内皮素-1及其受体ETAR和ETBR在乳腺癌溶骨性骨转移中的作用，以及它们如何受肝细胞生长因子和转化生长因子（HGF、TGF-β）及缺氧的调节。目的是通过内皮素-1介导的上皮-间质转化（EMT）或其逆过程间质-上皮转化（MET），以及通过骨模拟来评估骨转移对微环境刺激的适应性，并探讨骨定植的可能关键特征。我们将低侵袭性（MCF-7）和高侵袭性（MDA-MB231）乳腺癌细胞以及1833骨转移克隆与配对的人原发性乳腺癌和骨转移灶进行了比较。亲本MDA-MB231细胞及其衍生的1833克隆对刺激的反应相反。在1833细胞中，TGF-β和缺氧增加了内皮素-1的释放，总体上降低了对植入很重要的侵袭性，而内皮素-1增强了MDA-MB231细胞的侵袭性。内皮素-1自分泌环促进了细胞内信号通路与细胞外刺激的协同作用，触发了1833细胞中的MET和MDA-MB231细胞中的EMT。仅在1833细胞中，HGF对内皮素-1的反式激活和释放产生负面影响，这表明这些刺激存在时间顺序，其中HGF触发的Wnt/β-连环蛋白通路在转移过程中起初始作用。然后，内皮素-1/ETAR赋予MET和骨模拟表型，激活了与Runx相关的转录因子2并表达金属蛋白酶9，促进了定植和骨溶解。对配对的人原发性导管癌和骨转移灶的研究结果为该分子研究提供了转化意义。内皮素-1、ETAR和ETBR与恶性潜能的获得相关，因为原位癌中已高表达。这些分子标志物可作为侵袭行为和侵袭/转移表型的预测指标。
