Isolation of Breast cancer CTCs with multitargeted buoyant immunomicrobubbles.
Circulating tumor cells (CTCs) are extremely rare cells found in blood of metastatic cancer patients. There is a need for inexpensive technologies for fast enrichment of CTCs from large blood volumes. Previous data showed that antibody conjugated lipid shell immuno microbubbles (MBs) bind and isolate cells from biological fluids by flotation. Here, blood stable MBs targeted to several surface markers for isolation of breast tumor cells were developed. MBs coated with anti human EpCAM antibodies showed efficient binding of EpCAM+ breast cancer cell lines SKBR 3, MCF 7, and MDA MB 453, whereas anti human EGFR MBs showed binding of EpCAMLOW/NEGATIVE cell lines MDA MB 231 and BT 549. Multitargeted anti human EpCAM/EGFR MBs bound all cell lines with over 95% efficiency. Highly concentrated MB bound tumor cells were collected in a microliter volume via an inverted vacuum assisted harvesting setup. Using anti EpCAM and/or anti EpCAM/EGFR MBs, an efficient (70 90% recovery and fast (30min) isolation of the above mentioned cells and cell clusters was achieved from 7.5mL of spiked human blood. Using anti EpCAM MBs and anti EpCAM/EGFR MBs, cytokeratin positive, CD45 negative CTCs were detected in 62.5% (10/16) of patients with metastatic breast cancer and CTC clusters were detected in 41.7% (5/12) of CTC positive samples. Moreover, in some samples MBs isolated cytokeratin positive, CD45 negative tumor derived microparticles. None of these structures were detected in blood from non epithelial malignancies. The fast and inexpensive multitargeted platform for batch isolation of CTCs can promote research and clinical applications involving primary tumors and metastases.
Colloids and surfaces. B, Biointerfaces