Tumour cell invasion is one of the most critical steps in malignant progression. It includes a broad spectrum of mechanisms, including both individual and collective cell migration, which enables them to spread towards adjacent tissue, and form new metastases. Understanding the mechanisms of cell spreading, and invasion, is crucial for effective anticancer therapy. Two modes of individual migration of tumour cells have been established in a three-dimensional environment. Mesenchymally migrating cells use proteases to cleave collagen bundles, and thus overcome the ECM barriers. Recently described protease-independent amoeboid mode of invasion has been discovered in studies of cancer cells with protease inhibitors. During my PhD study, I have focused on determining the molecular mechanisms involved in amoeboid invasion of tumour cells. We have examined invasive abilities in non-metastatic K2 and highly metastatic A3 rat sarcoma cell lines. We have shown that even though highly metastatic A3 rat sarcoma cells are of mesenchymal origin, they have upregulated Rho/ROCK signalling pathway. Moreover, A3 cells generate actomyosin-based mechanical forces at their leading edges to physically squeeze through the collagen fibrils by adopting an amoeboid phenotype. Amoeboid invasiveness is also less dependent on...

Yes / Expression of the transmembrane NG2 chondroitin sulphate proteoglycan (CSPG) defines a distinct population of NG2-glia. NG2-glia serve as a regenerative pool of oligodendrocyte progenitor cells in the adult central nervous system (CNS), which is important for demyelinating diseases such as multiple sclerosis, and are a major component of the glial scar that inhibits axon regeneration after CNS injury. In addition, NG2-glia form unique neuron–glial synapses with unresolved functions. However, to date it has proven difficult to study the importance of NG2-glia in any of these functions using conventional transgenic NG2 ‘knockout’ mice. To overcome this, we aimed to determine whether NG2-glia can be targeted using an immunotoxin approach. We demonstrate that incubation in primary anti-NG2 antibody in combination with secondary saporin-conjugated antibody selectively kills NG2-expressing cells in vitro. In addition, we provide evidence that the same protocol induces the loss of NG2-glia without affecting astrocyte or neuronal numbers in cerebellar brain slices from postnatal mice. This study shows that targeting the NG2 CSPG with immunotoxins is an effective and selective means for killing NG2-glia, which has important implications for studying the functions of these enigmatic cells both in the normal CNS, and in demyelination and degeneration.