Fluorinated Cell Surfaces to Modulate Biological Function

描述（由申请人提供）：拟议研究的目标是探索表面装饰有非天然氟化碳水化合物的活细胞的生物学和生物物理特性。已经发现这种细胞表面修饰减少了细胞粘附，因此可能为治疗由细胞粘附介导的人类疾病过程（如肿瘤转移和炎症）提供了一种手段。该项目的部分目的是确定细胞表面氟修饰对与细胞粘附相关的生物功能的影响。氟化唾液酸降低肿瘤转移率或程度的能力将在小鼠模型中通过生物发光成像进行研究。用化学合成的氟化唾液酸类似物孵育细胞，使氟化分子附着在细胞表面，这些类似物被吸收并加工成在细胞糖萼上表达的氟化糖蛋白和糖脂。该项目的一部分工作是确定在细胞表面表达氟化唾液酸类似物的结构要求。此外，修饰分子在细胞表面的分布和性质将通过二次离子质谱法、选择性切割细胞表面分子的比色测定和化学遗传学方法来确定。由于未经修饰的细胞中几乎不存在氟化分子，因此氟原子的结合为非侵入性技术的低背景成像提供了机会。用含氟唾液酸处理荷瘤小鼠，用19F核磁共振成像成像。由于许多肿瘤细胞是高唾液化的，这项技术可能有助于在肿瘤通过其他方法可见之前定位肿瘤。本研究的具体目的是：(1)确定在培养细胞上耐受表达的氟化唾液酸类似物的范围；(2)评价氟化唾液酸表达细胞的静态粘附特性，研究其粘附改变的机制；(3)表征表达氟化碳水化合物的细胞表面；(4)评价细胞表面氟化对小鼠肿瘤转移的影响；(5)评价表达氟化碳水化合物的含瘤小鼠的19F MRI。公共卫生相关性：这项拟议的研究与癌症治疗有关，并可能与炎症性疾病有关，因为它探索了一种减少细胞粘附的新策略。这项研究也与癌症诊断有关，因为它可能提供一种通过MRI成像肿瘤的方法。

DESCRIPTION (provided by applicant): The goal of the proposed study is to explore the biological and biophysical properties of living cells that are decorated with unnatural fluorinated carbohydrates on their surfaces. It has been found that this cell-surface modification reduces cell adhesion, and therefore may provide a means to treat human disease processes that are mediated by cell adhesion such as tumor metastasis and inflammation. Part of this project is designed to determine the effect of cell-surface fluorine modification on biological functions related to cellular adhesion. The ability of fluorinated sialic acids to reduce the rate or extent of tumor metastasis will be studied by bioluminescent imaging in a murine model. The attachment of fluorinated molecules to the cell surface is accomplished by incubating the cells with chemically synthesized fluorinated sialic acid analogues that are taken up and processed into fluorinated glycoproteins and glycolipids expressed on the cell glycocalyx. Part of this project is to determine what the structural requirements are for a fluorinated sialic acid analogue to be expressed on the cell surface. Also, the distribution and nature of modified molecules on the cell surface will be determined by secondary ion mass spectrometry, by colorimetric assay of selectively cleaved cell-surface molecules, and by a chemical genetics approach. Since fluorinated molecules are virtually absent in unmodified cells, the incorporation of fluorine atoms provides an opportunity for low-background imaging by non-invasive techniques. Tumor bearing mice treated with fluorinated sialic acids will be imaged by 19F MRI. Since many tumor cells are hypersialylated, this technique may be useful for locating tumors before they are visible by other means. The Specific Aims for this study are to: (1) determine the scope of fluorinated sialic acid analogues tolerated for expression on cultured cells; (2) evaluate the static adhesion characteristics of cells expressing fluorinated sialic acids and study the mechanism of altered adhesion; (3) characterize the surfaces of cells expressing fluorinated carbohydrates; (4) evaluate the effect of cell-surface fluorination on tumor metastasis in mice; and (5) evaluate 19F MRI of tumor-containing mice expressing fluorinated carbohydrates. PUBLIC HEALTH RELEVANCE: The proposed study is relevant to cancer therapy and potentially to inflammatory disease because it explores a new strategy for reducing cell adhesion. The study is also relevant for cancer diagnosis because it may provide a way to image tumors by MRI.