Characterizing Cancer Cells Using Gedi Microdevices: Capture, In-Situ Analysis And Elution For Ex-Situ Analysis And Culture

Abstract

Several methodologies exist for the isolation of circulating tumor cells (CTCs) from cancer patient blood samples. However, there are few straightforward functional analyses for these cells, either downstream or in-situ, particularly in immunocapture-based systems. My thesis work has focused on two methods of cell extraction, and one in-situ assay, that can enable single-cell CTC interrogation using Geometrically Enhanced Differential Immunocapture (GEDI) microdevices. I will also present a non-mechanical, non-enzymatic, method of whole-cell release by substituting standard biotin-avidin immunochemistry with reversible biotin analogues. These data are one of the first demonstration of linker chemistry substitution for release of cancer cells, and can be combined with various biomechanical assays (e.g. traction force microscopy) to quantify an individual cells properties. Together, these methods provide a toolbox for straightforward extraction of cancer cells from CTC-capture devices, which can enable characterization of individual cell genotype and phenotype. I will also outline experiments which combine high-efficiency, high-purity GEDI cell capture with single-nucleus sequencing (SNS) for single-cell copy-number variation analyses (GEDI-SNS). I will show that GEDI-SNS is comparable to standard methods, can be used to identify key cancer-related genetic variations, and can differentiate between different cancer cell populations of the same tissue ori- gin. Finally, I will present the development of an on-chip assay to monitor Ca2+ homeostasis, which has been shown to be critical in taxane chemoresistance, as well as acquisition of a hormonally-independent phenotype. Using real-time, time-lapse, microscopy, I will monitor Ca2+ flux in cancer cells as a functional assay to inform drug treatment.