Bartkowiak Kai, Mossahebi Mohammadi Parinaz, Gärtner Sebastian, Kwiatkowski Marcel, Andreas Antje, Geffken Maria, Peine Sven, Verpoort Karl, Scholz Ursula, Deutsch Thomas M, Michel Laura L, Schneeweiss Andreas, Thewes Verena, Trumpp Andreas, Müller Volkmar, Riethdorf Sabine, Schlüter Hartmut, Pantel Klaus
Department of Tumour Biology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany.
Laboratory for Metabolic Signaling, Institute of Biochemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
J Proteome Res. 2023 Apr 7;22(4):1213-1230. doi: 10.1021/acs.jproteome.2c00739. Epub 2023 Mar 16.
In cancer metastasis, single circulating tumor cells (CTCs) in the blood and disseminated tumor cells (DTCs) in the bone marrow mediate cancer metastasis. Because suitable biomarker proteins are lacking, CTCs and DTCs with mesenchymal attributes are difficult to isolate from the bulk of normal blood cells. To establish a procedure allowing the isolation of such cells, we analyzed the cell line BC-M1 established from DTCs in the bone marrow of a breast cancer patient by stable isotope labeling by amino acids in cell culture (SILAC) and mass spectrometry. We found high levels of the transmembrane protein CUB domain-containing protein 1 (CDCP1) in breast cancer cell lines with mesenchymal attributes. Peripheral blood mononuclear cells were virtually negative for CDCP1. Confirmation by CellSearch revealed CDCP1-positive CTCs in 8 of 30 analyzed breast cancer patients. Only EpCam-positive CTCs were enriched by CellSearch. Using the extracellular domain of CDCP1, we established a magnetic-activated cell sorting (MACS) approach enabling also the enrichment of EpCam-negative CTCs. Thus, our approach is particularly suited for the isolation of mesenchymal CTCs with downregulated epithelial cancer that occur, for example, in triple-negative breast cancer patients who are prone to therapy failure.
在癌症转移过程中，血液中的单个循环肿瘤细胞（CTC）和骨髓中的播散肿瘤细胞（DTC）介导癌症转移。由于缺乏合适的生物标志物蛋白，具有间充质特性的CTC和DTC难以从大量正常血细胞中分离出来。为了建立一种能够分离此类细胞的方法，我们通过细胞培养中的氨基酸稳定同位素标记（SILAC）和质谱分析，对从一名乳腺癌患者骨髓中的DTC建立的细胞系BC-M1进行了分析。我们发现具有间充质特性的乳腺癌细胞系中跨膜蛋白含CUB结构域蛋白1（CDCP1）水平较高。外周血单核细胞几乎没有CDCP1。CellSearch检测证实，在30例分析的乳腺癌患者中有8例存在CDCP1阳性的CTC。CellSearch仅富集EpCam阳性的CTC。利用CDCP1的胞外结构域，我们建立了一种磁激活细胞分选（MACS）方法，也能够富集EpCam阴性的CTC。因此，我们的方法特别适用于分离上皮癌下调的间充质CTC，例如在易于治疗失败的三阴性乳腺癌患者中出现这种情况。
