Schwartz-Albiez R, Steffen I, Lison A, Güttler N, Schirrmacher V, Keller R
German Cancer Research Center, Institute of Immunology and Genetics, Heidelberg, Federal Republic of Germany.
Br J Cancer. 1988 Jun;57(6):569-75. doi: 10.1038/bjc.1988.130.
Even though many studies suggest that proteoglycans with their structurally determinative polysaccharide chains, the glycosaminoglycans (GAGs), are important mediators of cellular interactions, little is known about expression and possible functions of these macromolecules expressed by tumour cells during the transition from low to highly metastatic behaviour. Therefore, we investigated the cellular expression and secretion of GAGs in a syngeneic tumour system of DBA/2 mice consisting of a methylcholanthrene-induced low metastatic T lymphoma (Eb), its highly metastatic spontaneous variant (ESb), and a low metastatic derivative of ESb (ESb-MP), selected by its adherent growth properties. The [35S]-sulphate-labelled GAGs were isolated from in vitro cultivated cells and further characterized by separation on Sepharose CL 6B, on Mono-Q ion exchange chromatography, and alkali- and enzymatic digestion. In contrast to Eb-cells which produce chondroitin/dermatan sulphate (CS/DS) and heparan sulphate (HS) (cellular extract: CS/DS 67%, HS 33%; culture medium: CS/DS 61%, HS 39%) ESb- and ESb-MP-cells only express and secrete CS/DS. For ESb cells the CS portions consisted of 42% chondroitin-4-sulphate (CS-4) and 58% chondroitin-6-sulphate (CS-6), for ESb-MP cells of 23% CS-4 and 77% CS-6, for Eb cells of 16% CS-4 and 84% CS-6. The cell surface GAGs of the adherent variant ESb-MP contained a significantly higher portion of DS (65%) compared to ESb cells (25%). GAGs of all tumour cell lines studied had a mol. wt ranging from 35-40 kD compared to GAG molecular weight standards. Ion exchange chromatography indicated that differences in charge density between GAGs of these cell lines were minimal. These findings suggest that the different biological behaviour of the cell lines cannot be attributed to altered size and charge density of their GAG chains. However, highly metastatic ESb-cells secreted significantly more GAG than low metastatic Eb- and ESb-MP-cells. The possible consequences of the enhanced secretion of CS/DS by ESb-cells are discussed in terms of the postulated role of CS/DS in cellular adhesion, growth regulation and interactions with the immune system.
尽管许多研究表明，带有结构决定性多糖链的蛋白聚糖，即糖胺聚糖（GAGs），是细胞间相互作用的重要介质，但对于肿瘤细胞在从低转移行为向高转移行为转变过程中所表达的这些大分子的表达情况及可能的功能却知之甚少。因此，我们在DBA/2小鼠的同基因肿瘤系统中研究了GAGs的细胞表达和分泌情况，该系统由甲基胆蒽诱导的低转移性T淋巴瘤（Eb）、其高转移性自发变体（ESb）以及ESb的低转移性衍生物（ESb-MP，根据其贴壁生长特性选择）组成。从体外培养的细胞中分离出[35S] - 硫酸盐标记的GAGs，并通过在琼脂糖CL 6B上分离、Mono-Q离子交换色谱以及碱和酶消化进一步进行表征。与产生硫酸软骨素/硫酸皮肤素（CS/DS）和硫酸乙酰肝素（HS）的Eb细胞（细胞提取物：CS/DS 67%，HS 33%；培养基：CS/DS 61%，HS 39%）不同，ESb和ESb-MP细胞仅表达和分泌CS/DS。对于ESb细胞，CS部分由42%的硫酸软骨素-4-硫酸盐（CS-4）和58%的硫酸软骨素-6-硫酸盐（CS-6）组成；对于ESb-MP细胞，CS-4为23%，CS-6为77%；对于Eb细胞，CS-4为16%，CS-6为84%。与ESb细胞（25%）相比，贴壁变体ESb-MP的细胞表面GAGs中硫酸皮肤素（DS）的比例显著更高（65%）。与GAG分子量标准相比，所有研究的肿瘤细胞系的GAGs分子量范围为35 - 40 kD。离子交换色谱表明，这些细胞系的GAGs之间的电荷密度差异极小。这些发现表明，细胞系不同的生物学行为不能归因于其GAG链大小和电荷密度的改变。然而，高转移性的ESb细胞分泌的GAG比低转移性的Eb和ESb-MP细胞显著更多。根据CS/DS在细胞黏附、生长调节以及与免疫系统相互作用中的假定作用，讨论了ESb细胞增强分泌CS/DS的可能后果。
