核酸适配子W3识别的外泌体靶标蛋白的鉴定及其在介导大肠癌转移微环境形成中的作用

转移是大肠癌患者致死的主要原因，发现和鉴定相关标志物对预测和治疗转移具有重要意义。近期研究显示，肿瘤细胞分泌的纳米级膜性囊泡-外泌体可通过介导细胞间的通讯参与肿瘤转移微环境形成，是肿瘤转移的潜在预测因子，但目前仍缺乏具有明确临床价值的特异性外泌体标志物。申请者前期采用Cell-SELEX技术筛选得到能够特异性识别转移性大肠癌细胞的核酸适配子W3，研究发现，W3靶蛋白可以外泌体形式进入患者外周血，体外、动物体内及肿瘤组织标本检测均显示W3靶蛋白表达水平与大肠癌转移特别是远端转移密切相关，由此推测，W3靶蛋白可能以外泌体形式参与肿瘤转移微环境形成。为此，本研究拟采用质谱技术从阳性外泌体中鉴定W3靶蛋白，并通过体内、体外实验及mRNA表达谱分析证实W3靶蛋白阳性外泌体通过与内皮细胞以及转移器官定居细胞的相互作用参与转移微环境重塑。通过血清学检测评价其临床应用价值，以期发现新的肿瘤转移相关标志物。

Metastasis is the leading cause of colorectal cancer related death. The identification of metastatic biomarkers is very important in cancer prognosis and therapy. Recent researches have demonstrated that the nanoscaled exosome secreted by tumor cells can participate in formation of tumor metastatic microenvironment by mediating intercellular communication and might be the potential prognostic factor of tumor metastasis. However, there have been few highly specific exosome markers with definite clinical value. We have previously selected the aptamer W3 that recognized metastatic colon cancer cells in highly specificity by Cell-SELEX. We also found that the target protein of aptamer W3 was secreted into blood circulation in form of exosome and the expression of target protein was significantly correlated with colon cancer metastasis in vitro and in vivo. Thus we assume that the target protein of aptamer W3 might participate in the formation of tumor metastatic microenvionment in form of exosome. In this study, we will identify target protein of aptamer W3 in exosome by mass-spectrometry technology. The interaction between target protein positive exosome with endothelial cells as well as resident cells in metastatic organs which participates in metastatic microenvironment remodeling will be investigate by in vitro, in vivo and mRNA expression profiling assays. The clinical value of target protein involved in the exsome will be evaluated by serological detection methods for the purpose of discovering novel metastatic biomarkers.