Proceedings of The Physiological Society
King's College London (2011) Proc Physiol Soc 22, C03
Blockade of ADAM10/17 impairs sphere growth and promotes neuronal differentiation from brain tumour stem cells.
H. Bulstrode1,2, W. P. Gray1,2, S. Willaime-Morawek1
1. Faculty of Medicine, University of Southampton, Southampton, United Kingdom. 2. Wessex Neurological Centre, Southampton University Hospital Trust, Southampton, United Kingdom.
High grade primary glial tumours are characterised by rapid proliferation and diffuse infiltration, contributing to a dismal prognosis. The recent concept of the tumour stem cell, able to proliferate indefinitely as well as generate progeny comprising the tumour bulk, leads us to the investigation of the niche within which these cells exist. Niche components include the ADAMs, cell surface proteins which contribute to cell-cell adhesion and have enzyme activity central to signalling, growth and invasion by tumours. We have derived sphere cultures derived from high grade tumour stem cells, and maintained these through multiple passages to amplify the stem cell component. Using RT-qPCR, we have established the expression profile of 10 ADAM molecules across 38 primary tumours and in sphere cultures developed from some of these. We have shown that compared to control adult and foetal neural tissue, ADAMs 10, 12, and 17 are over-expressed in low grade tumours, more so in high grade tumours, and to a greater degree still in the stem-cell-enriched sphere cultures. We have used immunohistochemistry to localise them within tissues and spheres. These tumours are known to be heterogeneous, and the pattern of ADAM overexpression differs from one sample to another, with a degree of overlap in function between ADAM family members. We have investigated the inhibition of ADAM function using pharmacological inhibitors, demonstrating an impact on sphere formation which correlates with the degree of over-expression in a given stem cell line. We have confirmed the specificity of the pharmacological inhibition with blocking antibodies. As well as impairing growth, we have observed marked effects on differentiation and resulting cell morphology, with potential implications for the pattern of invasion.ADAMs represent a promising therapeutic target in a group of tumours notoriously refractory to existing treatments.
Where applicable, experiments conform with Society ethical requirements