Quantitative Analysis of Multiple Proteins of Different Invasive Tumor Cell Lines at the Same Single-Cell Level.

Tumor cell invasion is pivotal to the development, metastasis, and prognosis of tumors. It is reported that the invasive ability of tumor cells is mainly dependent on the expression levels of membrane type-1 matrix metalloproteinase (MT1-MMP) and integrin alpha(V)beta(3) proteins on cell membranes. To precisely distinguish between tumor cells with different invasive abilities, it is important to establish a highly sensitive and precise quantification method to differentiate the expression levels of MT1-MMP and integrin alpha(V)beta(3) in the same single tumor cell at the same time. Herein, two functional peptides to construct red-emissive Au-26 clusters and green-emissive Ag-12 clusters are reported. Moreover, the Au-26 clusters and Ag-12 clusters have the ability to specifically target MT1-MMP and integrin alpha(V)beta(3), respectively, in the same single cell at the same time. By utilizing the fluorescent properties and metallic compositions of metal clusters, the MT1-MMP and integrin alpha(V)beta(3) levels of the more invasive SiHa cells or the less invasive HeLa cells are simultaneously and quantitatively differentiated via laser ablation inductively coupled plasma mass spectrometry. This method of quantitatively detecting multiple invasive proteins on the same cell is of great value for accurately diagnosing aggressive tumors and monitoring the invasiveness of these tumors.