Abstract：
Epithelial-mesenchymal transition (EMT) promotes tumor cell infiltration and metastasis. Tracking the progression of EMT could potentially indicate early cancer metastasis. A key characteristic of EMT is the dynamic alteration in the molecular levels of E-cadherin and N-cadherin. Traditional assays have limited sensitivity and multiplexing capabilities, relying heavily on cell lysis. Here, we developed a multiplex electrochemical biosensor to concurrently track the upregulation of N-cadherin expression and reduction of E-cadherin in breast cancer cells undergoing EMT. Small-sized gold nanoparticles (Au NPs) tagged with redox probes (thionin or amino ferrocene) and bound to two types of antibodies were used as distinguishable signal tags. These tags specifically recognized E-cadherin and N-cadherin proteins on the tumor cell surface without cross-reactivity. The diphenylalanine dipeptide (FF)/chitosan (CS)/Au NPs (FF-CS@Au) composites with high surface area and good biocompatibility were used as the sensing platforms for efficiently fixing cells and recording the dynamic changes in electrochemical signals of surface proteins. The electrochemical immunosensor allowed for simultaneous monitoring of E- and N-cadherins on breast cancer cell surfaces in a single run, enabling tracking of the EMT dynamic process for up to 60 h. Furthermore, the electrochemical detection results are consistent with Western blot analysis, confirming the reliability of the methodology. This present work provides an effective, rapid, and low-cost approach for tracking the EMT process, as well as valuable insights into early tumor metastasis.
摘要：
上皮-间质转化（EMT）促进肿瘤细胞浸润和转移。跟踪EMT的进展可能提示早期癌症转移。EMT的关键特征是E-cadherin和N-cadherin分子水平的动态改变。传统的测定具有有限的灵敏度和多路复用能力,严重依赖细胞裂解。这里,我们开发了一种多重电化学生物传感器，以同时追踪接受EMT的乳腺癌细胞中N-cadherin表达的上调和E-cadherin的减少。用氧化还原探针(硫素或氨基二茂铁)标记并与两种类型的抗体结合的小尺寸金纳米颗粒(AuNP)用作可区分的信号标签。这些标签特异性识别肿瘤细胞表面上的E-钙黏着蛋白和N-钙黏着蛋白而没有交叉反应性。利用具有高表面积和良好生物相容性的二苯丙氨酸二肽（FF）/壳聚糖（CS）/AuNPs（FF-CS@Au）复合材料作为传感平台，有效地固定细胞并记录表面蛋白质电化学信号的动态变化。电化学免疫传感器允许在单次运行中同时监测乳腺癌细胞表面上的E-和N-钙黏着蛋白，能够跟踪EMT动态过程长达60小时。此外，电化学检测结果与Westernblot分析一致,确认方法的可靠性。目前的工作提供了一种有效的，快速,以及跟踪EMT过程的低成本方法，以及对早期肿瘤转移的有价值的见解。
