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Studying the impact of physical forces on cancer cells Determining how cancer cells respond to physical forces in their cellular environment could improve cancer treatment, according to two UC researchers. Professor Maan Alkaisi and Dr Volker Nock (Electrical and Computer Engineering) have been investigating how physical forces in the micro-nano environment of the body influence how cells develop, spread and interact, in order to understand ways cancer treatment could be enhanced. “Cancers are more susceptible to metastasise and spread depending on the stiffness of tissue. It becomes almost an engineering problem if you can determine what forces cancer cells experience in the body,” Nock says. “We are trying to determine if there are ways of treating cancer from a different perspective, not from a mutation-based perspective. There seems to be a connection between mechanical stiffness and cancer development and, if we can determine that and how that affects the biochemistry of the cells, then there’s potential to develop drugs that will help.” Alkaisi and Nock, who have collaborated with Christchurch Hospital and researchers at Toulouse University in France, have developed cutting-edge “bioimprint” technology to find out how physical forces in the micro-nano environment influence cell behaviour. “Physical forces range from nano to microNewtons, so they are extremely small forces that we are talking about,” Alkaisi says. 24 University of Canterbury He says bioimprint technology enables researchers to mimic how cells react by recreating imitation cells in polymeric material with features of a similar size and shape to that of a cell’s morphology. “We can essentially replicate the micro-nano environment of the cell by replicating the cell itself in some polymer, which we use as a platform to culture cells and see how cells react to an environment that mimics the shape, topography and dimensions of an actual cell. We can do this in a variety of environments, both positive and negative, for the cell to grow and interact,” Alkaisi says. “We have results that show that forces do influence the morphology, including the shape or even genetic expression. What the cell secretes is also different on different topographies, which means the cell membrane can interact within an environment and produce different types of protein to deal with different situations.” Nock previously worked with a microscopic worm, C. elegans, to see how the environment the worm moves in influences forces exerted by it during locomotion. “We used a worm which is an excellent model for all sorts of diseases. We designed devices with arrays of miniature sensor pillars in which we could track its movement and every time it touches a pillar we can measure the force it exerts by recording the deflection of the pillar. “We can apply this to cancer cells. We have the system and we know it works; it is just a matter of making it smaller for individual cells. There are some interesting engineering challenges around the system but, in principle, we know it works,” Nock says. Alkaisi says bioimprint technology allows researchers to determine the difference in the role of the micro-nano environment and that of surface chemistry. “This is probably one of the best technologies to isolate these two factors. We have a topography that exactly mimics the environment so we can isolate the chemical from the physical influences,” he says. Alkaisi and Nock, whose research has been supported by the Marsden Fund, want to apply their discoveries to measure the forces cancer cells exert on the micro-nano environment, what size the forces are, how cancer cells grow and interact with their environment where tissue is both soft and hard. “First, we will measure the forces that cancer cells exert on the environment and what the size of those forces are,” Alkaisi says. “We will look at 3D clusters of cancer cells — spheroids — growing and see how they push the surrounding environment under different conditions. We are going to use the set of pillars developed by Volker and measure the deflection of these pillars. From these deflections we can extract the mechanical and physical forces the cancer is applying.” Alkaisi says the ultimate goal will then be to discover how to apply external forces on the cancer cells and look at any changes in genetic expression and changes in growth rate, spread or behaviour. “There is an argument in the scientific community that triggered this research which proposes that by applying certain forces, cancer cells can be reverted back to normal cells, which, if that could be achieved, would be pretty amazing,” Alkaisi says. “What we want to do is to build a model whereby we characterise, exactly, the magnitude and nature of the forces required to induce changes and possibly reverse cancer growth.” Alkaisi says they hope to focus on ovarian cancer, ultimately using live cancer cells from patients, because it prefers soft tissue whereas breast cancer prefers stiffer tissue. “There is certainly a response to the environment; this might explain why certain parts of the body are more vulnerable to cancer than others. I want to discover what is missing in cancer treatment. Once we know what impact mechanical forces could have on cancer cells then that might give us an idea for developing better, more effective treatment,” Alkaisi says. “Medical doctors cannot create devices on such a small scale to measure forces and detect these changes so we are hoping this is an area we can help in.” Research supported by: • Marsden Fund By Renee Jones (From left) Professor Maan Alkaisi and Dr Volker Nock Research Report 2014 25