Plasma Membrane Proteins in Myeloid-Derived Suppressor Cells

描述(申请人提供)：髓系来源的抑制细胞(MDSC)抑制对肿瘤生长的自然免疫反应，并阻止抗癌免疫治疗的临床效果。MDSC是由炎症诱导的，通过抑制肿瘤反应性T淋巴细胞的激活和利用巨噬细胞的功能来调节其作用。该项目将确定MDSC识别和附着T淋巴细胞和巨噬细胞的分子机制，并阐明炎症和癌症之间的分子联系。初步证据支持这一假设，即肿瘤患者的MDSC通过质膜受体接收促进激活和积聚的信号。我们将通过识别潜在的受体来测试这一点，并确定通过这些受体的激活是否会增加MDSC的抑制活性，并促进MDSC的积累和/或滞留。将对植入乳腺癌的小鼠的低水平和高水平炎症的MDS细胞的蛋白质表达/丰度进行定量比较。将实施新技术，以方便地分离质膜，并广泛识别表面受体和其他差异表达的蛋白质。这些措施包括开发一种重金属纳米线薄膜以简化离心分离；通过化学切割步骤消除凝胶电泳；通过磁性纳米管去除双层脂类；以及为含有跨膜结构域的中长肽定制的化学和生物信息处理。

DESCRIPTION (provided by applicant): Myeloid-derived suppressor cells (MDSC) suppress the natural immune-response to tumor growth, and prevent the clinical effectiveness of immunotherapy against cancer. MDSC are induced by inflammation and mediate their effects by inhibiting the activation of tumor-reactive T-lymphocytes and by co-opting macrophage function. This project will identify molecular mechanisms by which MDSC recognize and attach to T- lymphocytes and macrophages, and illuminate the molecular connection between inflammation and cancer. Preliminary evidence supports the hypothesis that MDSC in tumor-bearing individuals receive signals promoting activation and accumulation through plasma membrane receptors. We will test this by identifying potential receptors and determining if activation through these receptors increases MDSC suppressive activity, and facilitates MDSC accumulation and/or retention. Protein expression/abundance will be compared quantitatively in MDS cells with low and high levels of inflammation from mice implanted with mammary carcinomas. New technologies will be implemented to enable facile isolation of the plasma membrane and extensive identification of surface receptors and other differentially expressed proteins. These include development of a heavy metal nanowire pellicle to simplify centrifugal isolation; elimination of gel electrophoresis with a chemical cleavage step; removal of bilayer lipids by magnetic nanotubes; and chemical and bioinformatic processing customized for mid-length peptides containing trans-membrane domains.