Kantara Carla, O'Connell Malaney Ravae, Luthra Gurinder, Gajjar Aakash, Sarkar Shubhashish, Ullrich Robert Leo, Singh Pomila
Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX, USA.
Department of Internal Medicine, The University of Texas Medical Branch, Galveston, TX, USA.
Lab Invest. 2015 Jan;95(1):100-12. doi: 10.1038/labinvest.2014.133. Epub 2014 Oct 27.
Cancer stem cells (CSCs) are believed to be resistant to currently available therapies and may be responsible for relapse of cancer in patients. Measuring circulating tumor cells (CTCs) in the blood of patients has emerged as a non-invasive diagnostic procedure for screening patients who may be at high risk for developing metastatic cancers or relapse of the cancer disease. However, accurate detection of CTCs has remained a problem, as epithelial-cell markers used to date are not always reliable for detecting CTCs, especially during epithelial-mesenchymal transition. As CSCs are required to initiate metastatic tumors, our goal was to optimize and standardize a method for identifying circulating CSCs (CCSCs) in patients, using established CSC markers. Here, we report for the first time the detection of CCSCs in the blood of athymic nude mice, bearing metastatic tumors, and in the blood of patients positive for colonic adenocarcinomas. Using a simple and non-expensive method, we isolated a relatively pure population of CSCs (CD45-/CK19+), free of red blood cells and largely free of contaminating CD45+ white blood cells. Enriched CCSCs from patients with colon adenocarcinomas had a malignant phenotype and co-expressed CSC markers (DCLK1/LGR5) with CD44/Annexin A2. CSCs were not found in the blood of non-cancer patients, free of colonic growths. Enriched CCSCs from colon cancer patients grew primary spheroids, suggesting the presence of tumor-initiating cells in the blood of these patients. In conclusion, we have developed a novel diagnostic assay for detecting CSCs in circulation, which may more accurately predict the risk of relapse or metastatic disease in patients. As CSCs can potentially initiate metastatic growths, patients positive for CCSCs can be treated with inhibitory agents that selectively target CSCs, besides conventional treatments, to reduce the risk of relapse/metastatic disease for improving clinical outcomes.
癌症干细胞（CSCs）被认为对目前可用的治疗方法具有抗性，并且可能是患者癌症复发的原因。检测患者血液中的循环肿瘤细胞（CTCs）已成为一种非侵入性诊断程序，用于筛查可能有发生转移性癌症或癌症疾病复发高风险的患者。然而，准确检测CTCs仍然是一个问题，因为迄今为止使用的上皮细胞标志物在检测CTCs时并不总是可靠的，尤其是在上皮-间质转化过程中。由于CSCs是启动转移性肿瘤所必需的，我们的目标是使用已建立的CSC标志物来优化和标准化一种识别患者循环CSCs（CCSCs）的方法。在这里，我们首次报告在患有转移性肿瘤的无胸腺裸鼠血液以及结肠腺癌阳性患者的血液中检测到CCSCs。使用一种简单且成本低廉的方法，我们分离出了相对纯净的CSCs群体（CD45-/CK19+），不含红细胞且基本不含污染的CD45+白细胞。来自结肠腺癌患者的富集CCSCs具有恶性表型，并与CD44/膜联蛋白A2共表达CSC标志物（DCLK1/LGR5）。在没有结肠生长物的非癌症患者血液中未发现CSCs。来自结肠癌患者的富集CCSCs形成了原发性球体，表明这些患者血液中存在肿瘤起始细胞。总之，我们开发了一种用于检测循环中CSCs的新型诊断方法，该方法可能更准确地预测患者复发或转移性疾病的风险。由于CSCs可能潜在地启动转移性生长，除了传统治疗外，CCSCs阳性的患者可以用选择性靶向CSCs的抑制剂进行治疗，以降低复发/转移性疾病的风险，从而改善临床结果。
