Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681844
Title: A proteomic approach to investigate the effects of extracellular matrix stiffness on endothelial cells
Author: Reid, Steven Edward
ISNI:       0000 0004 5921 9592
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 2015
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Abstract:
One of the most common symptoms that people associate with cancer is the formation of a lump in soft tissue. This is a sign of abnormal tissue stiffness and can be derived from changes in the extracellular matrix (ECM). This physical property is known to be a consequence and promoter of tumour development. The abnormally high tumour stiffness is typically derived from increased crosslinking of the ECM. The aim of this project was to ascertain how the increased tissue stiffness, that is found within and around the tumour affects the endothelial cells that make up the vasculature. To do this I generated hydrogels representing an ECM stiffness of normal tissue and a tumour like ECM stiffness. Using high resolution mass spectrometry combined with stable isotope labelling of amino acids in cell culture (SILAC), I analysed the global proteome of primary human umbilical vein endothelial cells (HUVECs) cultured at each ECM stiffness. I found that many proteins involved in cell adhesion were upregulated, including N-Cadherin and CCN1. I demonstrated that stiffness induced CCN1 mediates both β-catenin activity and N-Cadherin expression. For the first time I show that CCN1, which is known as a secreted protein, can mediate these effects without exiting the cell, demonstrating an intracellular role for CCN1 in HUVECs. N-Cadherin is known to play a key role in trans-endothelial migration of cancer cells through the blood vessels, and I found that CCN1 induces cancer cell adhesion to HUVECs via N-Cadherin. This suggests that CCN1 can increase cancer cell metastasis by aiding the exit of cancer cells from the primary tumour and entry at distant sites. To test this hypothesis in vivo, we used a C57BL/6 Ccn1 loxP/loxP syngeneic melanoma model. To knock out Ccn1, a soluble form of Cre was utilised, which can be up taken into cells and has been shown previously to specifically target cells of the vasculature. Our results show that knocking out Ccn1 in the ECs decreased the number of circulating tumour cells and subsequent metastases, showing that Ccn1 loss in the vasculature can decrease cancer cell intravasation. Our work provides evidence of an unprecedented mechanism through which CCN1 in the stromal cells promotes invasion of cancer cells, which compliments the findings that CCN1 can induce invasion in the cancer cells. We provide further evidence that targeting CCN1 therapeutically in the clinic may decrease the spread of cancer from the perspective of the endothelial cells.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.681844  DOI: Not available
Keywords: Q Science (General) ; RC0254 Neoplasms. Tumors. Oncology (including Cancer)
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