From the ‡Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania.
§Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts.
Mol Cell Proteomics. 2018 Apr;17(4):619-630. doi: 10.1074/mcp.RA117.000370. Epub 2018 Jan 20.
Breast cancer mortality predominantly results from dormant micrometastases that emerge as fatal outgrowths years after initial diagnosis. In order to gain insights concerning factors associated with emergence of liver metastases, we recreated spontaneous dormancy in an all-human hepatic microphysiological system (MPS). Seeding this MPS with small numbers (<0.05% by cell count) of the aggressive MDA-MB-231 breast cancer cell line, two populations formed: actively proliferating ("growing"; EdU), and spontaneously quiescent ("dormant"; EdU). Following treatment with a clinically standard chemotherapeutic, the proliferating cells were eliminated and only quiescent cells remained; this residual dormant population could then be induced to a proliferative state ("emergent"; EdU) by physiologically-relevant inflammatory stimuli, lipopolysaccharide (LPS) and epidermal growth factor (EGF). Multiplexed proteomic analysis of the MPS effluent enabled elucidation of key factors and processes that correlated with the various tumor cell states, and candidate biomarkers for actively proliferating (either primary or secondary emergence) dormant metastatic cells in liver tissue. Dormancy was found to be associated with signaling reflective of cellular quiescence even more strongly than the original tumor-free liver tissue, whereas proliferative nodules presented inflammatory signatures. Given the minimal tumor burden, these markers likely represent changes in the tumor microenvironment rather than in the tumor cells. A computational decision tree algorithm applied to these signatures indicated the potential of this MPS for clinical discernment of each metastatic stage from blood protein analysis.
乳腺癌死亡率主要源于休眠的微转移灶，这些转移灶在初始诊断多年后才会发展为致命性肿瘤。为了深入了解与肝转移出现相关的因素，我们在全人源肝脏微生理系统（MPS）中重现了自发休眠。在这个 MPS 中，我们以低细胞数（按细胞计数<0.05%）接种侵袭性 MDA-MB-231 乳腺癌细胞系，形成了两个群体：活跃增殖的（“生长”；EdU）和自发静止的（“休眠”；EdU）。用临床标准化疗药物处理后，增殖细胞被消除，只有静止细胞保留；然后，通过生理相关的炎症刺激（脂多糖[LPS]和表皮生长因子[EGF]）可以将这个残留的休眠群体诱导到增殖状态（“出现”；EdU）。对 MPS 流出物进行的多重蛋白质组学分析，阐明了与各种肿瘤细胞状态相关的关键因素和过程，以及候选生物标志物，用于鉴定肝组织中活跃增殖（原发性或继发性出现）休眠转移性细胞。休眠与细胞静止相关的信号比原始无肿瘤肝脏组织更强烈，而增殖性结节呈现出炎症特征。鉴于肿瘤负担极小，这些标志物可能代表肿瘤微环境的变化，而不是肿瘤细胞的变化。应用于这些特征的计算决策树算法表明，该 MPS 有潜力通过血液蛋白分析从临床角度区分每个转移阶段。
