Carcinoembryonic antigen and CD44 variant isoforms cooperate to mediate colon carcinoma cell adhesion to E- and L-selectin in shear flow
Carcinoembryonic antigen and CD44 variant isoforms cooperate to mediate colon carcinoma cell adhesion to E- and L-selectin in shear flow
复制标题
DOI：
10.1074/jbc.m800543200
复制
发表时间：
2008-06-06
影响因子：
4.8
通讯作者：
Konstantopoulos, Konstantinos
中科院分区：
文献类型：
--
作者：
Thomas, Susan N.;Zhu, Fei;Konstantopoulos, Konstantinos
选择素介导的肿瘤细胞与血小板、白细胞和内皮细胞的粘附可以调节它们在微血管系统中的血行播散。我们最近发现CD 44变体亚型（CD 44 v）是结肠癌细胞上功能性P-选择素配体，而不是E-或L-选择素配体。此外，一种类似于180-kDa的唾液酸岩藻糖基化糖蛋白介导了CD 44敲低细胞中的选择素结合。使用免疫亲和层析和串联质谱，我们确定这种糖蛋白的癌胚抗原（CEA）。使用包被有从LS 174 T结肠癌细胞免疫纯化的CEA的微珠和选择素作为底物的印迹滚动测定和基于流动的粘附测定揭示CEA具有E-和L-，但不是P-，选择素配体活性。CD 44敲低的LS 174 T细胞上的CEA表现出比野生型细胞上的CEA更高的HECA-452免疫反应性，表明CEA作为选择素结合聚糖的替代受体发挥作用。来自CD 44敲低细胞的CEA上HECA-452反应性表位的表达增强与CEA对E-而非L-选择素的亲合力增加相关。通过产生稳定的敲除细胞系，我们证明CEA作为一种辅助L-选择素配体，其稳定L-选择素依赖性细胞滚动对流体剪切。此外，CEA和CD 44 v合作介导结肠癌细胞粘附E-和L-选择素在升高的剪切应力。CEA是E-和L-选择素配体的新发现可以解释与肿瘤细胞CEA过表达相关的增强的转移潜力和选择素在转移中的支持作用。
Selectin-mediated adhesion of tumor cells to platelets, leukocytes, and endothelial cells may regulate their hematogenous dissemination in the microvasculature. We recently identified CD44 variant isoforms (CD44v) as functional P-, but not E- or L-, selectin ligands on colon carcinoma cells. Moreover, an similar to 180-kDa sialofucosylated glycoprotein(s) mediated selectin binding in CD44-knockdown cells. Using immunoaffinity chromatography and tandem mass spectrometry, we identify this glycoprotein as the carcinoembryonic antigen (CEA). Blot rolling assays and flow-based adhesion assays using microbeads coated with CEA immunopurified from LS174T colon carcinoma cells and selectins as substrate reveal that CEA possesses E- and L-, but not P-, selectin ligand activity. CEA on CD44-knockdown LS174T cells exhibits higher HECA-452 immunoreactivity than CEA on wild-type cells, suggesting that CEA functions as an alternative acceptor for selectin-binding glycans. The enhanced expression of HECA-452 reactive epitopes on CEA from CD44-knockdown cells correlates with the increased CEA avidity for E- but not L-selectin. Through the generation of stable knockdown cell lines, we demonstrate that CEA serves as an auxiliary L-selectin ligand, which stabilizes L-selectin-dependent cell rolling against fluid shear. Moreover, CEA and CD44v cooperate to mediate colon carcinoma cell adhesion to E- and L-selectin at elevated shear stresses. The novel finding that CEA is an E- and L-selectin ligand may explain the enhanced metastatic potential associated with tumor cell CEA overexpression and the supportive role of selectins in metastasis.