Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 4 uppsatser.

published_or_final_version / abstract / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Choroidal neovascularization (CNV) is a leading threat to severe vision loss, particularly in patients with age-related macular degeneration (AMD). In CNV, newly formed blood vessels sprout from the choroid to the sub-retinal space, where leakage and bleeding of the abnormal vessels lead to photoreceptor death and subsequent vision loss. It is believed that CNV is mediated by growth factors (e.g. vascular endothelial growth factor {VEGF}) produced by the retinal pigment epithelium (RPE) under pathological states (e.g. hypoxia). Current treatments for CNV aiming at countering VEGF only help decrease leakage and inhibit formation of CNV, but none of them is curative and the recurrence rate remains high. In order to find other more powerful potential therapeutic targets, the regulations of VEGF signaling in the pathophysiology of CNV is the focus of numerous translational investigations. Previously, Hypoxia-inducible factor-1 (HIF-1), a crucial transcriptional factor in response to hypoxia, is identified as the master transcriptional factor controlling VEGF expression in the RPE promoting CNV. Alpha-enolase (ENO1), a key glycolytic enzyme, is known to be over expressed in several types of carcinomas also under the regulation of HIF-1. ENO1 has been reported to be closely associated with cancer progression, angiogenesis, and venous invasion. The molecular events of ENO1 in the pathogenesis of promoting angiogenesis are of interest but still barely understood. Recently, the association of ENO1 antibodies with retina has been seen in patients with AMD. We hypothesize that ENO1 expression in the RPE may play a role in the development of CNV, participating in the regulation of VEGF. Hypoxia is an important pathological condition in the formation of CNV. Here, we first determined ENO1 expression and cell death in a human RPE cell line, ARPE-19, under cobalt (II) chloride (CoCl2)-induced hypoxia or anoxia (95% N2, 5% CO2). To further investigate the regulation of ENO1 in CNV, HIF-1α-diminished RPE cells were generated using small interfering RNA (siRNA) and the change of ENO1 expression in response to hypoxic injury was determined. Upon 24 hr of treatment with CoCl2-induced hypoxia or anoxia, the expression of ENO1 and VEGF increased significantly along with HIF-1α in ARPE-19 cells, both of which could in turn be significantly down-regulated by HIF-1α siRNA. Interestingly, cell death remained low in ARPE-19 cells, even after 24 hr of CoCl2-induced hypoxia or anoxia. To further study the role of ENO1 in CNV, we started by investigating the relationship between ENO1 and VEGF. SiRNA was used to knock down the expression of ENO1 in ARPE-19 cells. Upon transfection with the siRNA, ENO1 expression was successfully down-regulated when treated with CoCl2-induced hypoxia. However, VEGF secretions from the ENO1-diminished ARPE-19 cells under CoCl2-induced hypoxia remained unchanged. Double knockdown of ENO1 together with HIF-1α by siRNA also did not help to further suppress VEGF secretion in the hypoxic ARPE-19 cells. Hence, ENO1 was demonstrated to be activated and up-regulated by HIF-1 in RPE cells responding to hypoxia, suggesting a potential role of ENO1 in favoring the formation of CNV, but not through influencing VEGF secretion. / published_or_final_version / Ophthalmology / Master / Master of Philosophy

Angiogenesis has a crucial influence on tumour development and identification of microvessels in malignant breast cancer tissue is an indicator for worse prognosis. Angiogenesis is partially governed by the family of vascular endothelial growth factors (VEGF) and their receptors, by which the VEGF-A-protein seems to be the most important factor.     The aims of this work were to first establish a method for immunohistological (IH)-staining of the VEGF-A-protein for clinical use and then to label and evaluate the expression of this protein in 31 Nottingham Histology Graded (NHG I-III) breast carcinoma.      Formaldehyde-fixated tissues from invasive breast neoplasms and control tissues were labelled with monoclonal antibodies against VEGF-A and CD31-proteins using a semi-automated IH-system from Ventana BenchMark. Positively stained vessels were counted from digital copies of microscopic pictures related to mm2 tissue.     A method of IH-labelling with VEGF-A protein was successfully established before staining of the breast tissue and in 19 of the 31 breast cancers. Vessels were counted for both antibodies. The VEGF-A-antibody stained 2.7 ± 2.3 (mean ± SD) vessels/mm2 and the CD31-antibody stained 27.3 ± 19.3 in the breast carcinoma tissue. The percent of VEGF-A-stained vessels in relation to CD31-stained were 7.6% in the NHG-I- (n=3), 7.8% in the NHG-II- (n=10) and 15.0% in the NHG-III-group (n=6).     The results demonstrate that increased NHG-grade and lower differentiation can be associated with higher percent of vessels expressing VEGF-A-protein. The result was not statistically certified because of the small number of stained breast cancers and additional investigations are recommended before clinical use.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph. D. in Cancer Biology)--Vanderbilt University, May 2008. / Title from title screen. Includes bibliographical references.

Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). "June 2008." Includes bibliographical references (leaves 65-72). Also available via the World Wide Web.