Takamatsu K, Auerbach B, Gerardy-Schahn R, Eckhardt M, Jaques G, Madry N
Research Laboratories of Behringwerke AG, Marburg, Germany.
Cancer Res. 1994 May 15;54(10):2598-603.
In human serum, at least two molecular species of the neural cell adhesion molecule (NCAM) with molecular weights of 110,000-130,000 and 150,000-180,000, respectively, can be identified by Western blotting. Both are characterized by the absence of epitopes for monoclonal antibodies KD11 and MG5, which specifically recognize intracellular domains of the human NCAM transmembrane isoforms, NCAM-140 and NCAM-180. In contrast to the M(r) 110,000-130,000 molecule also detectable in serum samples from healthy blood donors, the M(r) 150,000-180,000 molecule appears to be tumor associated. The only difference between these two species is shown to be the presence of long chains of alpha-(2,8)-linked N-acetylneuraminic acids, which are characteristic for the so-called embryonic NCAM form. After treatment with endoneuraminidase N, the M(r) 150,000-180,000 molecule can no longer be discriminated from the M(r) 110,000-130,000 molecule in Western blotting as well as gel and anion exchange chromatography experiments. The experimental data clearly show that only the embryonic NCAM molecule carrying the poly-alpha-(2,8)-linked N-acetylneuraminic acid moiety can be regarded as a specific serum marker for small cell lung cancer.
在人血清中，通过蛋白质免疫印迹法可鉴定出至少两种分子量分别为110,000 - 130,000和150,000 - 180,000的神经细胞黏附分子（NCAM）分子种类。这两种分子的特征是不存在单克隆抗体KD11和MG5的表位，这两种单克隆抗体可特异性识别人类NCAM跨膜异构体NCAM - 140和NCAM - 180的胞内结构域。与在健康献血者血清样本中也可检测到的分子量为110,000 - 130,000的分子不同，分子量为150,000 - 180,000的分子似乎与肿瘤相关。已表明这两种分子之间的唯一区别在于存在α-(2,8)-连接的N-乙酰神经氨酸长链，这是所谓胚胎型NCAM形式的特征。用神经氨酸酶N处理后，在蛋白质免疫印迹以及凝胶和阴离子交换色谱实验中，分子量为150,000 - 180,000的分子与分子量为110,000 - 130,000的分子无法再区分开来。实验数据清楚地表明，只有携带多聚α-(2,8)-连接的N-乙酰神经氨酸部分的胚胎型NCAM分子可被视为小细胞肺癌的特异性血清标志物。
