Hildebrandt H, Becker C, Glüer S, Rösner H, Gerardy-Schahn R, Rahmann H
Institut für Zoologie (220), Universität Hohenheim, Stuttgart, Germany.
Cancer Res. 1998 Feb 15;58(4):779-84.
Neuroblastomas and cell lines derived from these tumors bear the oncodevelopmental antigen polysialic acid (PSA) bound to the neural cell adhesion molecule. Polysialyation of neural cell adhesion molecule can be achieved by two different polysialyltransferases, ST8SiaII and ST8SiaIV. This study was undertaken to investigate the pattern of polysialyltransferases expressed in the human neuroblastoma cell line SH-SY5Y. Reverse transcription-PCR showed simultaneous expression of the two enzymes, and in situ hybridization demonstrated that the polysialyltransferase mRNA expression parallels immunoreactivity with the PSA-specific monoclonal antibody 735. After retinoic acid-induced differentiation, only the PSA-positive, neuron-like cell type gave clear signals for ST8SiaII and ST8SiaIV in in situ hybridization, whereas both signals were drastically reduced in the weakly PSA-positive substrate adherent phenotype. Like the SH-SY5Y cells, a primary, PSA-positive neuroblastoma specimen revealed expression of the two polysialyltransferases. To investigate the role of PSA for cell growth and differentiation, SH-SY5Y cells were treated with the PSA-specific endo-N-acetylneuraminidase E. Although loss of PSA was accompanied with a marked reduction of cell growth, it did not interfere with retinoic acid-induced differentiation. Together, our results suggest that PSA surface expression is regulated on the level of polysialyltransferase transcription. Moreover, the similarity to the primary neuroblastoma tissue makes SH-SY5Y cells a suitable model system to examine further the role of polysialylation in tumor cell growth and the orchestration of PSA synthesis in neuroblastoma.
神经母细胞瘤以及源自这些肿瘤的细胞系表达与神经细胞黏附分子结合的肿瘤发生相关抗原多唾液酸（PSA）。神经细胞黏附分子的多唾液酸化可由两种不同的多唾液酸转移酶ST8SiaII和ST8SiaIV实现。本研究旨在调查人神经母细胞瘤细胞系SH-SY5Y中多唾液酸转移酶的表达模式。逆转录聚合酶链反应显示这两种酶同时表达，原位杂交表明多唾液酸转移酶mRNA表达与PSA特异性单克隆抗体735的免疫反应性平行。维甲酸诱导分化后，仅PSA阳性的神经元样细胞类型在原位杂交中给出ST8SiaII和ST8SiaIV的清晰信号，而在PSA弱阳性的贴壁底物表型中两种信号均显著降低。与SH-SY5Y细胞一样，一个原发性PSA阳性神经母细胞瘤标本显示两种多唾液酸转移酶的表达。为了研究PSA对细胞生长和分化的作用，用PSA特异性内切N-乙酰神经氨酸酶E处理SH-SY5Y细胞。尽管PSA的缺失伴随着细胞生长的显著减少，但它并不干扰维甲酸诱导的分化。总之，我们的结果表明PSA表面表达在多唾液酸转移酶转录水平上受到调控。此外，与原发性神经母细胞瘤组织的相似性使SH-SY5Y细胞成为一个合适的模型系统，可进一步研究多唾液酸化在肿瘤细胞生长中的作用以及神经母细胞瘤中PSA合成的调控。
