The presence of cancer biomarkers in peripheral blood creates an opportunity for diagnosis and monitoring of disease via a simple blood draw – a liquid biopsy. Circulating tumor cells (CTCs) are cells that have escaped into the bloodstream, a fraction of which have the potential to seed metastatic tumors. CTCs are exceedingly rare (about one in billion cells in blood) and heterogeneous, which both complicates their detection and motivates single-cell analysis to identify invasive or resistant subpopulations. Previously, we reported the selective capture of CTCs through dielectrophoresis (DEP) at wireless bipolar electrodes (BPEs) within a microfluidic device. Alignment of these electrodes to cell-sized pockets allows for cells to be isolated individually and then transferred into nanoliter-scale chambers for subsequent biomolecular analysis.<br/>Here, we report a method for single-cell protease activity assay following individual isolation of CTCs on this platform. Matrix metalloprotease 9 (MMP9) is a cell secreted proteolytic enzyme that facilitates increased invasiveness of CTCs by cleaving proteins of the extracellular matrix. Increased MMP9 activity is therefore an important indicator of the invasive potential of CTCs. Our method evaluates MMP9 activity at the single-cell level, which allows for identification of invasive subpopulations. We report the development and validation of this method using cultured tumor cell lines in the presence and absence of a stimulant for MMP9 secretion and then preliminary application of this method to analysis of CTCs from patient-derived samples.

Label-free selection of circulating tumor cells by dielectrophoresis and evaluation of invasive potential by single-cell protease activity assay

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.