Peptide microarray-based fluorescence assay for quantitatively monitoring the tumor-associated matrix metalloproteinase-2 activity

Matrix metalloproteinases (MMPs) are important biomarkers of various tumors. Herein, a peptide microarray-based fluorescence assay is developed for quantitatively profiling of MMP-2 activity in different matrices through the binding of the immobilized biotinylated peptides on the microarray with the fluorescein isothiocyanate (FITC) modified neutravidins. In the presence of MMP-2, the biotin moiety is released from microarray by enzymatic cleavage of peptide substrate, resulting in the decrease of fluorescence signal. The change of fluorescence intensity is correlated with MMP-2 activity. The detection limit down to 14 pg mL(-1) in buffer solution is obtained by a selected peptide substrate for MMP-2 from eleven peptide substrate candidates. The cellular secreted MMP-2 activity levels of different living cells are further successfully quantitatively evaluated by the selected peptide substrate. Using mouse-bearing MG-63 human osteosarcoma as a model system, we also demonstrate that the activity of MMP-2 in serum is closely related with the cancer progression.