Expression of the Clustered NeuAcα2-3Galβ O-Glycan Determines the Cell Differentiation State of the Cells
Expression of the Clustered NeuAcα2-3Galβ O-Glycan Determines the Cell Differentiation State of the Cells
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DOI：
10.1074/jbc.m114.550848
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发表时间：
2014-09-12
影响因子：
4.8
通讯作者：
Saito, Koichi
中科院分区：
文献类型：
--
作者：
Higashi, Kiyoshi;Asano, Kouji;Saito, Koichi
人胚胎干细胞（human embryonic stem cells，hESC）是来源于早期胚胎的多能干细胞，其自我更新能力依赖于hESC特异性分子的持续表达和分化相关基因的抑制表达。为了发现hESC上表达的新分子，我们产生了一组针对未分化hESC的单克隆抗体，并评估了它们标记癌细胞以及hESC的能力。MAb 7识别未分化的hESC，并在hESC的裂解物中显示分子量> 239 kDa的弥散带。尽管一些羊膜上皮细胞表达MAb 7抗原，但在正常人角质形成细胞、成纤维细胞或内皮细胞中几乎未检测到其表达。MAb 7抗原的表达仅在胰腺癌和胃癌细胞中观察到，并且其水平在转移性和低分化癌细胞系中升高。MAb 7抗原的分析表明，DMBT 1上成簇的NeuAc α 2-3Gal β O-连接的寡糖（在恶性脑肿瘤1中缺失）对于MAb 7在癌细胞中的结合至关重要。MAb 7抗原表位与TRA-1-60抗原表位相似，但在癌细胞中的分布与TRA-1-60抗原不同。暴露组蛋白去乙酰化酶抑制剂分化的胃癌MKN 74细胞诱发MAb 7抗原的表达，而DMBT 1表达保持不变。细胞分选后进行DNA微阵列分析鉴定了MKN 74细胞中负责MAb 7抗原生物合成的下调基因。此外，用MAb 7处理转移性胰腺癌细胞显著消除了对内皮细胞的粘附。这些结果提出了MAb 7表位是未分化细胞如hESC和癌症干细胞样细胞的新标记物的可能性，并且在未分化细胞中起可能的作用。
Human embryonic stem cells (hESCs) are pluripotent stem cells from early embryos, and their self-renewal capacity depends on the sustained expression of hESC-specific molecules and the suppressed expression of differentiation-associated genes. To discover novel molecules expressed on hESCs, we generated a panel of monoclonal antibodies against undifferentiated hESCs and evaluated their ability to mark cancer cells, as well as hESCs. MAb7 recognized undifferentiated hESCs and showed a diffuse band with molecular mass of > 239 kDa in the lysates of hESCs. Although some amniotic epithelial cells expressed MAb7 antigen, its expression was barely detected in normal human keratinocytes, fibroblasts, or endothelial cells. The expression of MAb7 antigen was observed only in pancreatic and gastric cancer cells, and its levels were elevated in metastatic and poorly differentiated cancer cell lines. Analyses of MAb7 antigen suggested that the clustered NeuAc alpha 2-3Gal beta O-linked oligosaccharides on DMBT1 (deleted in malignant brain tumors 1) were critical for MAb7 binding in cancer cells. Although features of MAb7 epitope were similar with those of TRA-1-60, distribution of MAb7 antigen in cancer cells was different from that of TRA-1-60 antigen. Exposure of a histone deacetylase inhibitor to differentiated gastric cancer MKN74 cells evoked the expression of MAb7 antigen, whereas DMBT1 expression remained unchanged. Cell sorting followed by DNA microarray analyses identified the down-regulated genes responsible for the biosynthesis of MAb7 antigen in MKN74 cells. In addition, treatment of metastatic pancreatic cancer cells with MAb7 significantly abrogated the adhesion to endothelial cells. These results raised the possibility that MAb7 epitope is a novel marker for undifferentiated cells such as hESCs and cancer stem-like cells and plays a possible role in the undifferentiated cells.