Rapid, reliable and unbiased circulating tumor cell (CTC) isolation and molecular characterization methods are urgently required for implementation in routine clinical diagnostic and prognostic procedures. We report on the development of a novel unbiased CTC detection approach that combines high-throughput automated microscopy with a simple yet efficient approach for achieving a high level of tumor cell binding in standard tissue culture polystyrene (PS) well plates. A single 5 min high-power oxygen plasma treatment was used to create homogeneous nanoscale roughness on standard PS tissue culture plates and, in turn, drastically enhance the binding of a range of tumor cells. After physical adsorption of an adlayer of poly-l-lysine, binding yields above 97% were obtained at 2 h for all tumor cell lines used in the study. Morphological analysis of the cells confirmed strong adherence to the nanorough PS substrates. Clinically relevant concentrations of a highly metastatic breast cancer cell line, used as model for CTCs, could be reliably detected among blood cells on the nanorough polystyrene plates using an automated microscopy system. The approach was then successfully used to detect CTCs in the blood of a stage IIIc colorectal cancer patient. By combining the high binding abilities of nanorough PS well plates with the high-throughput nature of high-content analysis systems, this methodology has great potential toward enabling unbiased routine clinical analysis of CTCs. It could be applied, once clinically validated, in any clinical center equipped with an automated microscopy facility at a fraction of the cost of current CTC isolation technologies.
Keywords: circulating tumor cells; colorectal cancer; high throughput microscopy; nanostructure; oxygen plasma; polystyrene.