Understanding the Role of the Solid Tumour Microenvironment in Brain Tumour Progression



Richards, R
(2017) Understanding the Role of the Solid Tumour Microenvironment in Brain Tumour Progression. PhD thesis, University of Liverpool.

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Abstract

Glioblastoma (GBM) is the most common malignant brain tumour and has an extremely poor prognosis. The invasion of tumour cells into normal brain tissue makes complete surgical removal impossible; GBM is also resistant to treatment with chemotherapy and radiotherapy. Our aim was to investigate how GBM cell proliferation, survival and invasion is affected by the solid tumour microenvironment. Although GBM is highly vascularised, the abnormal structure and function of tumour blood vessels results in an inadequate supply of oxygen (hypoxia). Hypoxia is known to promote tumour progression; however, the effect of hypoxia on cell proliferation has not been well characterised. We performed a systematic investigation into the effects of different oxygen levels on the cell cycle. In contrast to the prevailing hypothesis, we found that long-term exposure to pathophysiological levels of hypoxia (1–8% O2) does not affect cell proliferation and viability and that even severe hypoxia (0.1% O2) has only minimal effects. We next sought to characterise the effect of hypoxia in multicellular tumour spheroids: 3D cell clusters that replicate important aspects of the tumour microenvironment. We characterised spheroids in terms of proliferation, survival and oxygenation and found that, in this more complex model, hypoxia was associated with reduced proliferation. We then used spheroids to develop a novel method for imaging cellular migration and invasion in 3D using lightsheet fluorescence microscopy (LSFM). We imaged spheroids over 24 h and then quantified the movements of up to 1200 cells per spheroid in terms of speed and straightness of movement. We were able to compare the movement of cells in different regions of spheroids, gaining insight into the behaviour of quiescent cells in the core of large (~500 μm), heterogeneous spheroids that had been exposed to hypoxia. This technique can be used to investigate the effect of the tumour microenvironment on cell motility and to gain insight into the mechanism of drugs that hinder the process of invasion.

Item Type: Thesis (PhD)
Divisions: Faculty of Health and Life Sciences > Faculty of Health and Life Sciences
Depositing User: Symplectic Admin
Date Deposited: 17 Aug 2017 15:39
Last Modified: 16 Jan 2024 17:21
DOI: 10.17638/03005579
Supervisors:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3005579