LGR5 positivity defines stem-like cells in colorectal cancer
LGR5 positivity defines stem-like cells in colorectal cancer
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DOI：
10.1093/carcin/bgt377
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发表时间：
2014-04-01
期刊：
影响因子：
4.7
通讯作者：
Gaiser, Timo
中科院分区：
文献类型：
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作者：
Hirsch, Daniela;Barker, Nick;Gaiser, Timo
像正常的结直肠上皮一样，结直肠癌（CRC）是分层组织的，包括具有干细胞样特性的细胞群。富含亮氨酸重复序列的G蛋白偶联受体5（LGR 5）与正常结直肠上皮中的这些干细胞相关;然而，LGR 5在CRC中的确切功能在很大程度上仍然未知。在这里，我们分析了短发夹RNA介导的LGR 5在CRC细胞系SW 480和HT-29中沉默的功能和分子后果。此外，我们将Lgr 5-EGFP-IRES-CreERT 2小鼠暴露于氧化偶氮甲烷/葡聚糖硫酸钠（AOM/DSS），其诱导炎症驱动的结肠肿瘤。然后将肿瘤流式分选成表达高或低水平Lgr 5的上皮细胞部分，并使用基因表达谱和阵列比较基因组杂交进行分子表征。SW 480 CRC细胞中LGR 5的沉默导致球体的耗尽，但不影响粘附生长的细胞。球体比贴壁细胞表达更高水平的几个干细胞相关基因，包括LGR 5。LGR 5的沉默降低了体外增殖、迁移和集落形成以及体内致瘤性。根据这些结果，NOTCH信号传导在LGR 5沉默后下调。在AOM/DSS诱导的结肠肿瘤中，Lgr 5高细胞显示出比Lgr 5低肿瘤细胞和Lgr 5高正常结肠细胞更高水平的几种干细胞相关基因和更高的Wnt信号传导。阵列比较基因组杂交显示，在任何肿瘤细胞组分中没有基因组不平衡。我们的数据阐明了LGR 5作为干细胞样细胞标记物在CRC中的作用机制。我们的功能和分子研究结果将肠道干细胞标记物LGR 5与干细胞样结直肠癌细胞联系起来。LGR 5沉默减少增殖、迁移和致瘤性以及NOTCH信号传导。原发性小鼠结肠肿瘤维持了基于Lgr 5的干细胞层次结构。
Like normal colorectal epithelium, colorectal carcinomas (CRCs) are organized hierarchically and include populations of cells with stem-like properties. Leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5) is associated with these stem cells in normal colorectal epithelium; however, the precise function of LGR5 in CRC remains largely unknown. Here, we analyzed the functional and molecular consequences of short hairpin RNA-mediated silencing of LGR5 in CRC cell lines SW480 and HT-29. Additionally, we exposed Lgr5-EGFP-IRES-CreERT2 mice to azoxymethane/dextrane sodium sulfate (AOM/DSS), which induces inflammation-driven colon tumors. Tumors were then flow-sorted into fractions of epithelial cells that expressed high or low levels of Lgr5 and were molecularly characterized using gene expression profiling and array comparative genomic hybridization. Silencing of LGR5 in SW480 CRC cells resulted in a depletion of spheres but did not affect adherently growing cells. Spheres expressed higher levels of several stem cell-associated genes than adherent cells, including LGR5. Silencing of LGR5 reduced proliferation, migration and colony formation in vitro and tumorigenicity in vivo. In accordance with these results, NOTCH signaling was downregulated upon LGR5 silencing. In AOM/DSS-induced colon tumors, Lgr5 high cells showed higher levels of several stem cell-associated genes and higher Wnt signaling than Lgr5 low tumor cells and Lgr5 high normal colon cells. Array comparative genomic hybridization revealed no genomic imbalances in either tumor cell fraction. Our data elucidate mechanisms that define the role of LGR5 as a marker for stem-like cells in CRC.Our functional and molecular findings link the intestinal stem cell marker LGR5 to stem-like colorectal cancer cells. LGR5 silencing reduced proliferation, migration and tumorigenicity, and NOTCH signaling. Primary mouse colon tumors maintained an Lgr5-based stem cell hierarchy.