Differentiated Human Colorectal Cancer Cells Protect Tumor-Initiating Cells From Irinotecan
Differentiated Human Colorectal Cancer Cells Protect Tumor-Initiating Cells From Irinotecan
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DOI：
10.1053/j.gastro.2011.03.052
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发表时间：
2011-07-01
期刊：
影响因子：
29.4
通讯作者：
Kranenburg, Onno
中科院分区：
文献类型：
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作者：
Emmink, Benjamin L.;Van Houdt, Winan J.;Kranenburg, Onno
背景与目的：正常组织的干细胞具有抵抗机制，使其能够在遗传毒性损伤中存活。肿瘤的干细胞样细胞由它们的肿瘤起始能力定义，并且可能保留了这些抗性机制，使它们对化疗具有抗性。我们研究了对拓扑异构酶I抑制剂伊立替康的耐药性与人类结肠球培养物和结肠直肠异种移植瘤小鼠的肿瘤启动潜力之间的关系。方法：结肠球培养物是从因原发性或转移性腺癌而接受结肠或肝脏切除术的患者获得的人类结直肠肿瘤标本中建立的。通过免疫印迹和荧光激活细胞分选分析干细胞和分化标志物。通过单细胞克隆和免疫缺陷小鼠评估克隆和肿瘤起始能力。在体外和荷瘤小鼠中评估了对伊立替康的敏感性。基于ABCB 1表达和乙醛脱氢酶（ALDH）活性，通过结肠球细胞的荧光激活细胞分选来测试耐药性和肿瘤起始能力之间的关系。结果：结肠球培养物在小鼠中具有高的引发肿瘤的能力，并且对伊立替康具有耐药性。PSC-833对药物外排泵ABCB 1的抑制使伊立替康能够根除肿瘤起始细胞。然而，ABCB 1仅由不形成克隆或肿瘤的分化肿瘤细胞亚群表达。相反，肿瘤起始细胞是ABCB 1阴性的，并通过高ALDH活性鉴定。致瘤性ALDH（高）/ABCB 1（阴性）细胞在体外和肿瘤异种移植物中产生非致瘤性ALDH（低）/ABCB 1（阳性）子细胞。PSC-833增加了伊立替康在小鼠中的抗肿瘤疗效。结论：结直肠肿瘤对伊立替康的耐药性需要肿瘤起始ALDH（高）/ABCB 1（阴性）细胞及其分化的药物驱逐ALDH（低）/ABCB 1（阳性）子细胞的协同作用。
BACKGROUND & AIMS: Stem cells of normal tissues have resistance mechanisms that allow them to survive genotoxic insults. The stem cell-like cells of tumors are defined by their tumor-initiating capacity and may have retained these resistance mechanisms, making them resistant to chemotherapy. We studied the relationship between resistance to the topoisomerase I inhibitor irinotecan and tumor-initiating potential in human colonosphere cultures and in mice with colorectal xenograft tumors. METHODS: Colonosphere cultures were established from human colorectal tumor specimens obtained from patients who underwent colon or liver resection for primary or metastatic adenocarcinoma. Stem cell and differentiation markers were analyzed by immunoblotting and fluorescence-activated cell sorting. Clone- and tumor-initiating capacities were assessed by single-cell cloning and in immune-deficient mice. Sensitivity to irinotecan was assessed in vitro and in tumor-bearing mice. The relationship between drug resistance and tumor-initiating capacity was tested by fluorescence-activated cell sorting of colonosphere cells, based on expression of ABCB1 and aldehyde dehydrogenase (ALDH) activity. RESULTS: Colonosphere cultures had a high capacity to initiate tumors in mice and were resistant to irinotecan. Inhibition of the drug-efflux pump ABCB1 by PSC-833 allowed irinotecan to eradicate tumor-initiating cells. However, ABCB1 was expressed only by a subpopulation of differentiated tumor cells that did not form clones or tumors. Conversely, tumor-initiating cells were ABCB1-negative and were identified by high ALDH activity. Tumorigenic ALDH(high)/ABCB1(negative) cells generated nontumorigenic ALDH(low)/ABCB1(positive) daughter cells in vitro and in tumor xenografts. PSC-833 increased the antitumor efficacy of irinotecan in mice. CONCLUSIONS: The resistance of colorectal tumors to irinotecan requires the cooperative action of tumor-initiating ALDH(high)/ABCB1(negative) cells and their differentiated, drug-expelling, ALDH(low)/ABCB1(positive) daughter cells.