Selection and Molecular Profiling of Circulating Tumor Cell (CTC) Sub-populations: Single-Cell Studies of Epithelial-to-Mesenchymal Transitions

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SELECTBIO

While metastic disease causes 90% of all cancer deaths, determining the role of various cancer cells in the metastatic process has been difficult due to the rare nature of these cells and the continuum of phenotypes they possess. To assist in studies based on the use of rare CTCs that may be involved in metastasis, an integrated system was designed, fabricated and evaluated. The system consisted of a cell selection unit, an electrical detector for enumeration, an imaging unit for phenotyping single cells and a molecular analysis unit for detecting mutations. The integrated system could correlate a cell’s phenotype to its genotype. The cell selection unit contained a series of 190 nL fluidic channels. The walls of the channels were decorated with antibodies used to recognize and select various sub-populations of CTCs. The cell selection unit could process 7.5 mL of whole blood in ~20 min with a selection efficiency of 97% and purity >80%. The CTCs were subsequently released from the surface-immobilized antibodies and enumerated by measuring impedance signatures of single cells that traversed through a pair of electrodes. The CTCs were then stained and phenotyped with the appropriate cells selected for molecular analysis. The CTCs were molecularly profiled by expression profiling certain genes from selected single cells. The use of the system for determining the molecular characteristics of CTC sub-populations involved in an epithelial-to-mesenchymal transition were evaluated using pancreatic cancer as the example disease.