The role of microtubule dynamics in cell division and chromosome segregation

Cancer cells are more deformable than healthy cells and deformability is likely linked to their metastatic potential. For instance, it is well-known that stiffness and elasticity of tissues change upon the presence of a tumour; what is less clear is the origin of these changes at the subcellular level and how these relate to the biology of a tumour cell. The cytoskeleton is a complex composite of microtubules, actin and intermediate filaments which helps to maintain the rigidity of cells and is critical to processes requiring movement and deformation of cells. The stability of the cytoskeleton is controlled by a variety of regulatory proteins. The microtubule depolymerizing kinesin, MCAK (KIF2C) is a major regulator of the microtubule cytoskeleton. In healthy cells, MCAK plays an important role in regulating microtubule length, particularly during mitosis and meiosis, where it also has a role in correction of chromosome-microtubule attachment errors. Knockdown of MCAK has a greater impact on cancer cells than healthy cells and alteration in expression mediates sensitivity to anti-microtubule cancer therapies. MCAK is overexpressed in breast, colorectal and gastric cancers and elevated expression correlates with increased metastasis and poor patient prognosis. We hypothesise that elevated levels of MCAK in cancer cells leading to destabilisation of the microtubule cytoskeleton increases cell deformability and in turn, metastatic potential. Hence, the overall aim of this project is to study the effect of perturbing the microtubule cytoskeleton, through manipulation of MCAK activity, on the mechanical properties of cells. Two different but complementary physical techniques will be used to quantify the mechanical properties of individual cells and these measurements compared with results from established cell biological assays which report on cell motility, deformability and proliferation. Although a body of evidence exists to connect overexpression of MCAK to progression of cancer, the link between MCAK activity and the mechanical properties of cells has not been investigated. Therefore, it is necessary and timely to use the biological tools now available to titrate MCAK activity and combine these with cutting edge physical techniques that report on cell mechanics to uncover the relationship between MCAK expression in cancer cells and increased metastatic potential and/or poor patient prognosis. MCAK is a target for new chemotherapeutic development, particularly to combat resistance to current anti-microtubule cancer drugs. The proposed work will add to our knowledge of the impact of MCAK in cancer cells and assist the development of drugs targeting MCAK activity. Further, the project will aid development of cutting edge biophysical techniques which will advance the use of cell mechanical properties as a novel label-free biomarker and diagnostic tool in the treatment of cancer.