A novel microchannel-based device to capture and analyze circulating tumor cells (CTCs) of breast cancer

Abstract

Circulating tumor cells (CTCs) have been shown in many studies as a possible biomarker for metastasis and may be instrumental for the spread of the disease. Despite advances in CTC capturing technologies, the low frequency of CTCs in cancer patients and the heterogeneity of the CTCs have limited the wide application of the technology in clinic. In this study, we investigated a novel microfluidic technology that uses a size- and deformability-based capture system to characterize CTCs. This unique platform not only allows flexibility in the selection of antibody markers but also segregates the CTCs in their own chambers, thus, enabling morphological, immunological and genetic characterization of each CTC at the single cell level. In this study, different breast cancer cell lines including MCF7, MDA-MB-231 and SKBR3, as well as a panel of breast cancer biomarkers were used to test the device. The technology can capture a wide range of cells with high reproducibility. The capturing efficiency of the cells is greater than 80%. In addition, the background of leukocytes is minimized because individual cells are segregated in their own chambers. The device captured both epithelial cancer cells such as MCF7 and SKBR3 and mesenchymal cells such as MDA-MB-231. Immunostaining of the captured cells on the microchannel device suggests that a panel of breast cancer biomarkers can be used to further characterize differential expression of the captured cells.

Size-Based Differentiation of Cancer and Normal Cells by a Particle Size Analyzer Assisted by a Cell-Recognition PC Software

“…[22][23][24] The capture, isolation and enrichment of non-adherent abnormal CTC are based on their difference from hematologic cells in size and biophysical deformities such as such as shape, stiffness and electrical polarizability. [13][14][15][16][17][18][25][26][27][28][29] Many studies have reported that tumor cells are larger in size as compared to hematologic cells and this difference accounts for the…”

“…8) On the other hand, it has been reported that non-adherent abnormal CTCs can be detected based on the expression of tumor antigens and biophysical deformities. 9,[11][12][13][14][15][16][17][18] The positive expression of CTC protein markers such as cytokeratin -8, -18 and -19, CD44 and the epithelial cell adhesion molecule (EpCAM) is often found in a CTC. 10) To date, the CellSearch system (Veridex, LLC, USA), which is based on immunostaining for CKs + , CD45 -and nucleus + , is the only device that is currently approved by the Food and Drug Administration for CTC detection,.…”

Circulating Tumor Cells: A Window into Tumor Development and Therapeutic Effectiveness

“…A thin plastic laminate was then laminated against the cyclic olefin polymer to create the final microchip that allowed blood cells to flow through, leaving the larger CTCs in the chamber. 110 Using the breast cancer cell lines MCF7, MDA-MB-231, and SK-BR-3 spiked into phosphate-buffered solution and human blood, the researchers captured more than 80% of the CTCs. 110 They were also able to show the differential expression of the cancer biomarkers PanCK, ERBB2 (formally known as HER2), ER, PI3K, E-cadherin, and vimentin in the cell lines tested by immunostaining antibodies and fluorescence microscopy.…”

“…110 Using the breast cancer cell lines MCF7, MDA-MB-231, and SK-BR-3 spiked into phosphate-buffered solution and human blood, the researchers captured more than 80% of the CTCs. 110 They were also able to show the differential expression of the cancer biomarkers PanCK, ERBB2 (formally known as HER2), ER, PI3K, E-cadherin, and vimentin in the cell lines tested by immunostaining antibodies and fluorescence microscopy. 110 The second study was conducted by a group from Japan who developed a novel, rapid CTC isolation device using a 3-dimensional palladium filter.…”

“…110,111 The first used photolithography and deep-reactive ion etching to create a micronetwork of cell-trapping chambers of 20 × 25 × 30 microns containing 8 to 10 micron pore channels. 110 From this master silicon template, a soft, elastomeric negative mold was forged by pouring and curing against the silicon master. The final microsubstrate was created by hot embossing a plastic plate made of cyclic olefin polymer against the elastomeric negative mold.…”