多功能化纳米材料络合物体外特异性结合和调控结肠癌细胞的研究

 循环肿瘤细胞(CTCs)因携带原发肿瘤的一些生物特性以及自身独特的生物学功能,在癌症的诊断、治疗和转移预防方面发挥着重要作用.但外周血中CTCs 的低含量使其检测、分离和富集有一定技术难度.本文选取结肠癌HT29 细胞为CTCs 模型,以表面高表达的EpCAM 为生物标记物,选取纳米级高分子聚合物G6 PAMAM dendrimers 为基质,多价络合针对EpCAM的抗体来构建络合物,实现体外对HT29 细胞的特异性捕获及活性调控.应用红外、动态光散射、紫外和荧光等方法表征络合物的理化特性,荧光分析法考察络合物对HT29 细胞的识别和捕获,MTT、荧光拍照、流式分析法显示络合物对捕获的HT29 细胞的活性调控.结果表明,制备的络合物可以高特异性地识别和结合贴壁的和悬浮的HT29 细胞,从而对捕获的细胞产生一定的活性下调作用,但不产生严重的细胞毒效应.可见,利用具有多价络合效应的纳米材料来共价连接针对CTCs 表面标记物的靶向抗体,有望实现在病人血中对CTCs 的特异性捕获和活性调控.

Specificity of Capturing and Restraining Colon Cancer Cells in Vitro by Multifunctional Nanomaterial Conjugates

Circulating tumor cells (CTCs) have great significance in cancer diagnosis, therapy and metastasis prevention, owing to their biological characteristics derived from themselves and primary tumor. However, low concentrations of CTCs in peripheral blood made their detection, isolation and enrichment technically challenging. In this study, we selected colon cancer HT29 cell as a CTC model and took the nanoscale G6 PAMAM dendrimers as scaffolds for multivalent conjugation with antibody against EpCAM to realize the specific capture and activity regulation at HT29 cells in vitro. FTIR, DLS, UV and fluorescence measurements were made to show the physicochemical properties of conjugates. Microscopic analysis was performed to indicate the recognition and capture behaviors to target cells. MTT, fluorescence and flow cytometric analyses were made to demonstrate the regulation on the viability of captured cells. Our results showed that the prepared conjugates were able to specifically recognize and bind the adherent and floating HT29 cells, and down-regulate the activity of captured cells without producing significant cytotoxic effects. The present study may provide promise for capturing and restraining the rare CTCs in patient blood by using nanomaterials multivalently conjugated with targeting antibodies against biomarkers on CTC surface.