Single-Cell Tracking of Breast Cancer Cells Enables Prediction of Sphere Formation from Early Cell Divisions
Patrick C. Bailey,
Rachel M. Lee,
Michele I. Vitolo,
Stephen J.P. Pratt,
Eleanor Ory,
Kristi Chakrabarti,
Cornell J. Lee,
Keyata N. Thompson,
Stuart S. Martin
Affiliations
Patrick C. Bailey
Graduate Program in Biochemistry, University of Maryland School of Medicine, 800 W. Baltimore St., Baltimore, MD 21201, USA
Rachel M. Lee
University of Maryland School of Medicine, Bressler Research Building Rm 10-29, 655 W. Baltimore St., Baltimore, MD 21201, USA; University of Maryland College Park, College Park, MD 20742, USA
Michele I. Vitolo
University of Maryland School of Medicine, Bressler Research Building Rm 10-29, 655 W. Baltimore St., Baltimore, MD 21201, USA; Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, 22 S. Greene St., Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore St., Baltimore, MD 21201, USA
Stephen J.P. Pratt
Graduate Program in Biochemistry, University of Maryland School of Medicine, 800 W. Baltimore St., Baltimore, MD 21201, USA
Eleanor Ory
University of Maryland School of Medicine, Bressler Research Building Rm 10-29, 655 W. Baltimore St., Baltimore, MD 21201, USA
Kristi Chakrabarti
University of Maryland School of Medicine, Bressler Research Building Rm 10-29, 655 W. Baltimore St., Baltimore, MD 21201, USA
Cornell J. Lee
University of Maryland School of Medicine, Bressler Research Building Rm 10-29, 655 W. Baltimore St., Baltimore, MD 21201, USA
Keyata N. Thompson
Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, 22 S. Greene St., Baltimore, MD 21201, USA
Stuart S. Martin
Graduate Program in Biochemistry, University of Maryland School of Medicine, 800 W. Baltimore St., Baltimore, MD 21201, USA; University of Maryland School of Medicine, Bressler Research Building Rm 10-29, 655 W. Baltimore St., Baltimore, MD 21201, USA; Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, 22 S. Greene St., Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore St., Baltimore, MD 21201, USA; Corresponding author
Summary: The mammosphere assay has become widely employed to quantify stem-like cells in a population. However, the problem is there is no standard protocol employed by the field. Cell seeding densities of 1,000 to 100,000 cells/mL have been reported. These high densities lead to cellular aggregation. To address this, we have individually tracked 1,127 single MCF-7 and 696 single T47D human breast tumor cells by eye over the course of 14 days. This tracking has given us detailed information for the commonly used endpoints of 5, 7, and 14 days that is unclouded by cellular aggregation. This includes mean sphere sizes, sphere-forming efficiencies, and a well-defined minimum size for both lines. Importantly, we have correlated early cell division with eventual sphere formation. At 24 hr post seeding, we can predict the total spheres on day 14 with 98% accuracy in both lines. This approach removes cell aggregation and potentially shortens a 5- to 14-day assay to a 24 hours. : Biology Experimental Methods; Cancer Subject Areas: Biology Experimental Methods, Cancer
