Ito Hiromi, Hoshi Kyoka, Osuka Fumihiko, Gotoh Mitsukazu, Saito Takuro, Hojo Hiroshi, Suzuki Rei, Ohira Hiromasa, Honda Takashi, Hashimoto Yasuhiro
Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima City, Japan.
Department of Regenerative Surgery, Fukushima Medical University School of Medicine, Fukushima City, Japan.
Proteomics. 2016 Dec;16(24):3081-3084. doi: 10.1002/pmic.201600117. Epub 2016 Sep 15.
Carcinoembryonic antigen (CEA) is a glycoprotein marker, which is widely used for diagnosing various cancers, especially colon adenocarcinoma. In addition, CEA mediates homotypic adhesion of colon adenocarcinoma cells, which appears to favor hematogenous metastasis. CEA carries α2,6sialyl residues on its N-glycans whereas a normal counterpart, normal fecal antigen-2, does α2,3sialyl residues, suggesting that cancer-specific α2,6sialylation on CEA may play a role for cell invasion and metastasis. A simple and rapid estimation of α2,6sialyled CEA in detergent extracts from formalin-fixed colon adenocarcinoma by "lectin inhibition" is reported. In the lectin inhibition method, Sambucus sieboldiana Agglutinin (SSA) lectin, an α2,6sialic acid binder, was used as a glycoform-specific inhibitor for antigen-antibody reaction in ELISA. Detergent extracts from colon adenocarcinoma showed a fair amount of ELISA signal in the absence of SSA whereas the signal was markedly reduced (45≈74%) in the presence of SSA, suggesting that the extracts contains α2,6sialyled CEA. The presence of α2,6sialyled CEA in the extracts was confirmed by lectin microarray, in which SSA, Sambucus nigra agglutinin, and Trichosanthes japonica agglutinin I lectins were used as α2,6sialyl binders. Thus lectin inhibition is a simple and rapid method for detecting α2,6sialyled CEA even in crude detergent extracts from formalin-fixed adenocarcinoma tissue.
癌胚抗原（CEA）是一种糖蛋白标志物，广泛用于诊断各种癌症，尤其是结肠腺癌。此外，CEA介导结肠腺癌细胞的同型黏附，这似乎有利于血行转移。CEA在其N聚糖上带有α2,6唾液酸残基，而正常对应物正常粪便抗原-2带有α2,3唾液酸残基，这表明CEA上癌症特异性的α2,6唾液酸化可能在细胞侵袭和转移中起作用。本文报道了一种通过“凝集素抑制”对福尔马林固定的结肠腺癌去污剂提取物中α2,6唾液酸化CEA进行简单快速估算的方法。在凝集素抑制法中，黑接骨木凝集素（SSA），一种α2,6唾液酸结合剂，被用作ELISA中抗原-抗体反应的糖型特异性抑制剂。在没有SSA的情况下，结肠腺癌的去污剂提取物显示出相当量的ELISA信号，而在有SSA的情况下，信号明显降低（45%≈74%），这表明提取物中含有α2,6唾液酸化CEA。提取物中α2,6唾液酸化CEA的存在通过凝集素微阵列得到证实，其中SSA、黑接骨木凝集素和日本栝楼凝集素I被用作α2,6唾液酸结合剂。因此，凝集素抑制是一种简单快速的方法，即使在福尔马林固定的腺癌组织的粗去污剂提取物中也能检测到α2,6唾液酸化CEA。
