New Way To Distinguish Cancerous From Normal Cells

The authors have identified a critical difference between the surface properties of normal and cancer cells: variation in brushes or tiny “hairs” that cover the cell surface.

The results imply that the brush layer cannot be ignored as was previously done when characterizing cells by mechanical methods. The authors suggest that the difference in the brush layers may have a biological significance, and can be used for detection of cancer.

Brushes on the cell surface, mostly consisting of microridges and tiny hairs called microvilli, are important for interacting with the external environment. Sokolov and his colleagues processed force measurements — taken from the cell surface using an atomic force microscope — according to a model that accounts for these brushes, to quantitatively show that cancerous cells are different. Normal cells have brushes of one length, whereas cancerous cells have mostly two brush lengths of significantly different densities.

The study is done with the help of a physical instrument, the atomic force microscope, which is not a conventional tool for biological research. As a result, the differences found were outside of what is conventionally measured in biology.

"Cancer cells are traditionally detected by biochemical means," says Sokolov. "However, despite many years of success, those methods have not resulted in defeating cancer. Therefore it is very important to search for alternative, nontraditional ways of looking at cancer. Investigation of the physical properties of cell surfaces might be one such nontraditional way."

The authors also demonstrated that the difference found in cell surface "brush" is practically impossible to find with other microscopic methods.

The research group consists of Sokolov, professor of physics and chemical & biomolecular science; Craig D. Woodworth, professor of biology; Swaminathan Iyer, a physics postdoctoral fellow; and Ravi M. Gaikwad and Venkatesh Subba-Rao, both physics graduate students.