Development of Mucin-mimetics to Study the Role of the Glycocalyx in Oncogenesis

 描述（由申请人提供）：粘蛋白在超过90%的乳腺癌和许多其他癌症中上调，并且它们与肿瘤发生的联系是明确的。尽管如此，他们的作用 大的细胞外结构域-糖萼的主要结构成分-在这种肿瘤发生中的作用还有待阐明。因为已知整合素介导的粘附在分化、增殖、迁移和凋亡等多种细胞过程中起关键作用， 异常的整联蛋白功能以多种方式与肿瘤发生有关。初步研究表明，粘蛋白可以通过改变糖萼的物理性质在促进整合素信号传导的促恶性功能中发挥作用。粘蛋白是高度O-糖基化的膜相关蛋白，参与保护上皮细胞免受管腔损伤。因为它们通常由大于50%的聚糖组成，所以它们的结构不容易使用标准分子生物学技术进行操作。研究这些分子的方法依赖于合成的粘蛋白模拟糖共聚物已被证明是克服这一障碍的一种易处理的方法。具有侧基酮的定义明确的聚合烷烃主链容易用氨氧基聚糖修饰。聚合物的一端含有用于显微镜检查的探针，另一端含有用于自发插入细胞膜的疏水尾。在这个建议中，我们将测试的假设，糖萼影响整合素介导的粘附在结构依赖性的方式，从而驱动转移表型，通过利用这些粘蛋白模拟。在具体目标1中，拟粘蛋白糖基共聚物将通过化学修饰其疏水锚而增加其在细胞表面上驻留更长时间的能力来改善。增加细胞表面半衰期将大大改善这些聚合物作为研究糖萼及其组分的工具。在特定目标2中，将使用这些工具研究糖萼的结构变异，并表征其对整合素驱动的转移表型的影响。如果得到证实，这一假设将提出一个范式转变的作用，粘蛋白和糖萼，在肿瘤发生。

 DESCRIPTION (provided by applicant): Mucins are upregulated in more than 90% of breast cancers and many other carcinomas, and their link to oncogenesis is clear. Still, the role of their large extracellular domains-a major structural component of the glycocalyx-in this oncogenesis has yet to be elucidated. Because it is known that integrin-mediated adhesion can play a critical role in such diverse cellular processes as differentiation, proliferation, migration and apoptosis, aberrant integrin function has been linked to oncogenesis in myriad ways. Preliminary studies suggest that mucins could play a role in boosting the pro-malignant functions of integrin signaling by changing the physical properties of the glycocalyx. Mucins are heavily O-glycosylated membrane-associated proteins involved in the protection of epithelia from luminal insults. Because they often consist of greater than 50% glycan by mass, their structures are not easily manipulated using standard molecular biology techniques. An approach to studying these molecules relying on synthetic mucin-mimetic glycopolymers has proven a tractable method to overcome this obstacle. Well-defined, polymeric alkane backbones with pendant ketones are easily decorated with aminooxy-glycans. One end of the polymer contains a probe for microscopy and the other a hydrophobic tail for spontaneous insertion into cell membranes. In this proposal we will test the hypothesis that the glycocalyx affects integrin-mediated adhesion in a structure dependent manner, and thus drives a metastatic phenotype, by utilizing these mucin-mimetics. In Specific Aim 1, mucin-mimetic glycopolymers will be improved by increasing their ability to reside on cell surfaces for longer periods of time by chemically modifying their hydrophobic anchors. Increasing cell-surface half-lives will vastly improve these polymers as tools with which to study the glycocalyx and its components. In Specific Aim 2, structural variation of the glycocalyx will be studied using these tools and its effect on integrin- driven metastatic phenotype will be characterized. If confirmed, this hypothesis would present a paradigm shift for the role of the mucins, and the glycocalyx, in oncogenesis.