title: Lipid tethering of breast tumor cells enables real-time imaging of free-floating cell dynamics and drug response.
abstract: Free-floating tumor cells located in the blood of cancer patients, known as circulating tumor cells (CTCs), have become key targets for studying metastasis. However, effective strategies to study the free-floating behavior of tumor cells in vitro have been a major barrier limiting the understanding of the functional properties of CTCs. Upon extracellular-matrix (ECM) detachment, breast tumor cells form tubulin-based protrusions known as microtentacles (McTNs) that play a role in the aggregation and re-attachment of tumor cells to increase their metastatic efficiency. In this study, we have designed a strategy to spatially immobilize ECM-detached tumor cells while maintaining their free-floating character. We use polyelectrolyte multilayers deposited on microfluidic substrates to prevent tumor cell adhesion and the addition of lipid moieties to tether tumor cells to these surfaces through interactions with the cell membranes. This coating remains optically clear, allowing capture of high-resolution images and videos of McTNs on viable free-floating cells. In addition, we show that tethering allows for the real-time analysis of McTN dynamics on individual tumor cells and in response to tubulin-targeting drugs. The ability to image detached tumor cells can vastly enhance our understanding of CTCs under conditions that better recapitulate the microenvironments they encounter during metastasis.
authors.affiliation: Medical Scientist Training Program, University of Maryland School of Medicine, Baltimore, MD 21201, USA.|Graduate Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.|Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Kristi R
authors.initials: KR
authors.lastname: Chakrabarti
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
authors.forename: James I
authors.initials: JI
authors.lastname: Andorko
authors.affiliation: Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.|Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Whipple
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
authors.forename: Peipei
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
authors.forename: Elisabeth L
authors.initials: EL
authors.lastname: Sooklal
authors.affiliation: Graduate Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.|Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.|Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Stuart S
authors.initials: SS
authors.lastname: Martin
authors.affiliation: Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.|Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.|Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Jewell
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000473:pathology*; D002448:Cell Adhesion / Q000502:physiology*; D002449:Cell Aggregation / Q000502:physiology*; D045744:Cell Line, Tumor; D022081:Cell Surface Extensions / Q000473:pathology; D003952:Diagnostic Imaging / Q000379:methods*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids; D061986:MCF-7 Cells; D009362:Neoplasm Metastasis / Q000473:pathology; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D059016:Tumor Microenvironment / Q000502:physiology
chemical_list: D000970:Antineoplastic Agents; D008055:Lipids
keywords: breast cancer; circulating tumor cells; microfluidics; microtentacles; polyelectrolyte multilayers