Heparan sulfate (HS) is a glycosaminoglycan found mainly in its protein-conjugated form at the cell surface and the extracellular matrix. Its high sulfation degree mediates functional interactions with positively charged amino acids in proteins. 2-O sulfation of iduronic acid and 3-O sulfation of glucosamine in HS are mediated by the sulfotransferases HS2ST and HS3ST, respectively, which are dysregulated in several cancers. Both sulfotransferases regulate breast cancer cell viability and invasion, but their role in cancer stem cells (CSCs) is unknown. Breast CSCs express characteristic markers such as CD44⁺/CD24^−/low, CD133 and ALDH1 and are involved in tumor initiation, formation, and recurrence. We studied the influence of HS2ST1 and HS3ST2 overexpression on the CSC phenotype in breast cancer cell lines representative of the triple-negative (MDA-MB-231) and hormone-receptor positive subtype (MCF-7). The CD44⁺/CD24^−/low phenotype was significantly reduced in MDA-MB-231 cells after overexpression of both enzymes, remaining unaltered in MCF-7 cells. ALDH1 activity was increased after HS2ST1 and HS3ST2 overexpression in MDA-MB-231 cells and reduced after HS2ST1 overexpression in MCF-7 cells. Colony and spheroid formation were increased after HS2ST1 and HS3ST2 overexpression in MCF-7 cells. Moreover, MDA-MB-231 cells overexpressing HS2ST1 formed more colonies and could not generate spheres. The phenotypic changes were associated with complex changes in the expression of the stemness-associated notch and Wnt-signaling pathways constituents, syndecans, heparanase and Sulf1. The results improve our understanding of breast CSC function and mark a subtype-specific impact of HS modifications on the CSC phenotype of triple-negative and hormone receptor positive breast cancer model cell lines.

硫酸乙酰肝素（HS）是一种糖胺聚糖，主要以蛋白结合的形式存在于细胞表面和细胞外基质中。它的高硫酸化度介导了蛋白质中带正电荷氨基酸的功能相互作用。在HS中，艾杜糖醛酸的2-O硫酸化和葡糖胺的3-O硫酸化分别由磺基转移酶HS2ST和HS3ST介导，它们在几种癌症中失调。两种磺基转移酶均调节乳腺癌细胞的生存能力和侵袭能力，但它们在癌症干细胞（CSC）中的作用尚不清楚。乳腺癌CSC表达特征性标志物，例如CD44 ⁺ / CD24- ^/低CD133和ALDH1与肿瘤的发生，形成和复发有关。我们研究了HS2ST1和HS3ST2过表达对代表三阴性（MDA-MB-231）和激素受体阳性亚型（MCF-7）的乳腺癌细胞系中CSC表型的影响。CD44 ⁺ / CD24- ^/低两种酶均过表达后，MDA-MB-231细胞的表型显着降低，而在MCF-7细胞中则保持不变。在MDA-MB-231细胞中HS2ST1和HS3ST2过表达后，ALDH1活性增加，而在MCF-7细胞中HS2ST1过表达后，ALDH1活性降低。HS2ST1和HS3ST2在MCF-7细胞中过表达后，集落和球状体的形成增加。此外，过表达HS2ST1的MDA-MB-231细胞形成更多的集落，并且无法生成球体。表型的变化与干性相关的缺口和Wnt信号通路的组成成分，Syndecans，乙酰肝素酶和Sulf1表达的复杂变化有关。