Abstract 5265: Development of a microfluidic device for tagless analysis of cell surface proteins directing lung metastasis

Abstract

Abstract Diagnostic analysis of the few tumor cells obtained by needle aspirates is currently limited to the cells’ morphologic characteristics. We are investigating tagless analysis of cell surface protein composition, when limited cell numbers are available, using a flow retardation microfluidic device. Expression of biologically significant cell surface proteins by individual cells is scored positive by achievement of flow retardation due to transient binding of cell surface proteins to cognizant antibodies immobilized on tandem patches of the channel. This permits repetitive queries of the same cell for several proteins that predict specific malignant behavior. We are adapting the model to LM2 cells, derived from lung metastases of MDA-MB-231 breast cancer cells, which selectively metastasize to the lung*. The original study identified 95 unique genes either overexpressed or underexpressed in LM2 cells compared to parental cells. Of these we identified three cell surface proteins, VCAM1, IL13RA2, and EMP1, as heterogeneously upregulated in a subset of LM2 cells and CXCR4, as downregulated in a subset of LM2 cells when compared with MDA-MB-231 cells. VCAM1 and IL13RA2 promote lung metastasis*. We sterile sorted LM2 cells into fractions expressing none, medium and high levels of these four proteins. We built a prototype microfluidic device able to retard the flow of streptavidin-coated silica oxide beads by immobilized biotin and used optical imaging and a tracking program for simultaneous analysis of multiple particles. We developed efficient and stable protein coating of microchannels and are generating patches with cognizant antibodies to these 4 antigens and to endothelial, macrophage, lymphocyte, fibroblast and endothelial cell markers as controls. We will correlate antigen expression levels with flow retardation efficiency. We will optimize shear rates affecting bond formation and shear stress affecting bond dissociation by optimizing velocity, viscosity, detergent and divalent cation concentrations to maximize cell separation. We will adapt the channel to select LM2 cells from excess controls in vitro and from tumor xenograft aspirates. *Minn AJ, Gupta GP, Siegel PM, Bos PD, Shu W, Giri DD, Viale A, Olshen AB, Gerald WL and Massague J (2005) Genes that mediate breast cancer metastasis to lung. Nature 436:518-524. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5265. doi:10.1158/1538-7445.AM2011-5265