Thesis (M.S.)--Baylor University, 2007. / Includes bibliographical references (p. 1-6 [second group]).

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 116-130). Also available in print.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 116-130). Also available online.

Indiana University-Purdue University Indianapolis (IUPUI) / Human papillomavirus 16 (HPV 16) causes cancer. Two viral oncoproteins of HPV 16, E6 and E7, are consistently expressed in these cancers. HPV 16 E6 and E7 proteins target p53 and Rb family members, respectively, for degradation thus inactivating the functiond of these tumor suppressor proteins. Tumor development requires the acquisition of a blood supply, a process known as angiogenesis. Tumor suppressors negatively regulate angigogenesis. Expression of HPV 16 E6 and E7 together in human foreskin keratinocytes (HFKs) increases the level of angiogenic inducers vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8). Further, conditioned media from such cells are sufficient to alter endothelial cell behavior both in vitro and in vivo. To determine the individual contributions of HPV E6 and E7 to angiogenesis, translational termination linkers (TTLs) were inserted into the coding region of E6 or E7. Following retroviral transduction of the mutated cassette into HFKs, the ability of E7 in the context of the E6TTL mutation (E6TTLE7) and E6 in the context of the E7TTL mutation (E6E7TTL) to induce VEGF and IL-8 was compared to the LXSN control retrovirus. E7 and, to a lesser extent E6, increased the expression of VEGF and IL-8. Migration of human microvascular endothelial cells was not induced using conditioned media from either E6 or E7 expressing cells. Since the increased levels of VEGF and IL-8 induced by HPV 16E6ETTLE7 were not sufficient to alter endothelial cell behavior, immunological depletion experiments were used to determine whether either angiogenic factor was required for HPV 16E6 and E7 together to induce HMVEC migration. Only VEGF was required. Preliminary data suggest that the ability of HPV 16 E7 to induce angiogenic factors is dependent upon degradation of a specific Rb family member.

published_or_final_version / abstract / Surgery / Doctoral / Doctor of Philosophy

Computational structural biology Even with rapid advances in structure determination methods, there is a long gap to be bridged between the number of proteins that have been sequenced and the number whose three-dimensional structures have been experimentally elucidated. Experimentally protein structures are determined by X-ray crystallography or by nuclear magnetic resonance spectroscopy (NMR). X-ray crystal structures give a time averaged picture but little information on conformational dynamics. Though NMR gives dynamical information, the technique cannot be applied to systems whose molecular weight is large. Only small proteins fall within the ken of NMR experiments. In most cases the three dimensional structure of the protein alone cannot give a complete picture of its mechanism. It is also essential to know the interactions of proteins with other proteins, with their ligands and substrates in order to have a better understanding of their functioning. Computer modeling and simulations are now indispensable supplements to experimental structural biology. The last word in protein structure prediction method is far from being said but the ever-improving homology and ab-initio modeling methods give rise to optimism that sometime in the near future these methods will become almost as reliable as experimental techniques. Ligand docking onto protein molecules is as challenging a problem as protein structure predicting itself. Computer modeling methods to dock ligands have to search a wide region of conformational space besides taking into consideration issues of charge and shape complementarities.

[Truncated abstract] One of the barriers to understanding and preventing proliferative diabetic retinopathy in humans has been the lack of an appropriate animal model. Historically dog, rat and mouse models of diabetic retinopathy have been studied but none of these exhibit the later changes of proliferative diabetic retinopathy. Animals can be rendered diabetic by surgical pancreatectomy or the use of chemicals such as allozan or streptozotocin or by feeding of a high galactose diet. Alternatively, spontaneous rodent models of diabetes have been examined such as the BB rat, KK mouse or NOD mouse. However, in each case the retinal vascular changes observed are those of early nonproliferative diabetic retinopathy comprising at most saccular microaneurysms, increased thickness of the capillary basement membrane, acellular capillaries and pericyte ghosts. … Fluorecein angiography of this transgenic line clearly demonstrates the presence of leaky new vessels, by the appearance of leakage spots scattered throughout the retina from 1 month of age. These mice constitute a valuable model of diabetic retinopathy. Neovascularization in this animal model is induced by VEGF as in human diabetic retinopathy. The source of VEGF in human diabetic retinopathy is the ischemic inner retina. In this transgenic model the source of VEGF are the photoreceptor cells, which are situated just underneath the inner retina. The neovascularization is not dependent on a particular developmental stage and there is no spontaneous regression of new vessels. Thus any results generated in this model are highly relevant to human diabetic retinopathy.

Diabetic retinopathy is an ischemic retinal neovascular disease causing vision loss among adults. The studies presented involve the design and testing of a gene therapy vector to inhibit retinal revascularization, similar to that found in diabetic retinopathy. Gene therapy has proven to be an effective method to introduce therapeutic proteins to treat retinal diseases. Targeting a specific cell type and expression of therapeutic proteins according to the tissue microenvironment should have an advantage over traditional gene therapy by avoiding unwanted transgene expression. Hypoxia plays a significant role in the pathophysiology of many retinal ischemic diseases. Retinal Mèuller cells provide structural and functional support to retinal neurons, as well as playing a significant role in retinal neovascularization. Targeting Mèuller cells may be an effective strategy to prevent retinal neovascularization under pathological conditions. ... The hypoxia regulated, glial specific vector successfully reduced the abnormal neovascularization in the periphery by 93% and reduced the central vasobliterated area by 90%. A substantial amount of exogenous endostatin was produced in the retinas of P17 OIR mice. A significant increase in human endostatin protein and reduced vascular endothelial growth factor (VEGF) were identified by Western blot and ELISA, respectively. These findings suggest hypoxia-regulated, glial cell-specific scAAV mediated gene expression may be useful to prevent blindness found in devastating retinal diseases involving neovascularization. / by Manas Ranjan Biswal. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

All the results showed that TCMs can provide a source for discovering anti-angiogenic agents for the treatment of cancer, and all these experiments in the zebrafish and mammalian models further confirmed the value of zebrafish model in anti-angiogenic drug discovery. / Angiogenesis refers to the formation of new blood capillaries from pre-existing ones, and is essential in a series of normal physiological processes such as embryonic development and pathological responses. However, persistent unregulated angiogenesis causes "angiogenic diseases" such as diabetic retinopathy, tumor growth and metastasis, rheumatoid arthritis, and inflammatory diseases. The linkage between angiogenesis, tumor growth and metastasis was first hypothesized by Dr. Judah Folkman in the 1970s, and now this controversial idea is widely accepted and the inhibition of angiogenesis, or anti-angiogenesis, is considered as a promising anticancer therapeutic strategy. Bevacizumab (Avastin RTM by Genentech Inc.), the first approved anti-angiogenic drug by U.S. FDA in 2004, is a humanized monoclonal antibody to inhibit endothelial cell proliferation and angiogenesis for the treatment of metastatic colorectal cancer, non-small cell lung cancer, advanced breast cancer, glioblastoma, metastatic renal cell cancer. / Anti-angiogenic therapy in cancer treatment has led to the development of compounds designed to control a tumor's growth by blocking its ability to develop a blood supply. The development of agents with different mechanisms of action requires powerful preclinical models for the analysis and optimization of the therapy. Some in vitro and in vivo anti-angiogenic assays are already developed, for example, Human Umbilical Vein Endothelial Cell (HUVEC) assay, Chorioallantoic Membrane assay, Matrigel plug assay et al. Zebrafish, as a relatively new model organism, is firmly established as a powerful research platform for many areas of biology and drug discovery, allowing the testing of bioactive compounds in a whole organism and in cells undergoing normal cell-cell and cell-matrix interactions. Many anti- and pro-angiogenic molecules tested in zebrafish demonstrated similar effects to those observed in humans or other mammalian models. Besides providing a powerful platform for drug screening, zebrafish model can also be used for probing biological processes, and generate insights into mechanisms. / Cancer is a generic term for a large group of diseases that can affect any part of the body, which causes a vast medical problem and is a leading cause of death worldwide nowadays. However, for many years the main methods of treating cancer have been surgery, radiotherapy and chemotherapy. Among these treatments, chemotherapy has played a major role in cancer therapy for half a century. Despite improving managements and efforts, it is not surprising that the prognosis has not greatly improved because of the limitations of current therapies, such as toxicity, inherent and acquired resistance, and metastatic spread. This calls for novel cancer therapies and new group of anticancer agents for selectively targeting cancers without or with lower toxicity to normal tissues. / Traditional Chinese medicines (TCMs) have long been recognized as a rich source for discovering drugs, and various TCMs and their components have shown anti-angiogenic properties. In this thesis study, as a continuing pursuit for elucidating the anti-angiogenic properties of TCMs, our attention is focused on those with effects of anti-inflammation, anti-rheumatoid arthritis and anti-cancer. On zebrafish screening model, three of the selected TCMs, Rheum palmatum, Alpinia oxyphylla (seeds), and Kaempferia galanga showed potential anti-angiogenic activity, indicating the existence of potent anti-angiogenic components in these herbs. The ethyl acetate fraction of R. palmatum showed strong inhibition of vessel formation in zebrafish embryos. Further testing of the anthraquinones of this herb showed three of them displayed potent anti-angiogenic activities. The most potent compound---rhein could inhibit HUVEC migration and affect the mRNA expression of vegfa, kdr, angiopoietin1/2 and tie1/2; The n-hexane and ethyl acetate fractions of A. oxyphylla and K. galangal showed anti-angiogenic potentials both in zebrafish and HUVEC assays. The n-hexane and ethyl acetate fractions of A. oxyphylla could both inhibit the proliferation, migration and tube formation processes of HUVEC. And the most potential component, trans-ethyl-p-methoxycinnamate from K. galanga, could inhibit HUVEC migration and tube formation, and reduce all gene expressions involved in angiogenesis process except for vegfa. / He, Zhiheng. / Adviser: Wei Ge. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 87-108). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Indiana University-Purdue University Indianapolis (IUPUI) / Choroidal neovascularization (CNV) is the vision-threatening characteristic of wet age-related macular degeneration (AMD), a major cause of blindness affecting almost 2 million elderly Americans. The current approved treatments target the dominant angiogenic mediator, vascular endothelial growth factor (VEGF). However, repeated injections of anti-VEGF drugs can cause ocular and systemic side effects, and about 30% of wet AMD patients are non-responsive. There is thus an unmet need to develop VEGF-independent antiangiogenic molecules to complement or combine with existing medications. I studied SH-11037, a novel homoisoflavonoid with potent and selective antiangiogenic activity against human retinal endothelial cells. Intravitreal SH- 11037 dose-dependently suppressed angiogenesis in the laser-induced CNV (LCNV) mouse model. These effects were prominent as early as 7 days post-laser treatment as measured by a novel ellipsoid quantification method of optical coherence tomography images in vivo. A supratherapeutic dose of 100 μM SH- 11037 was not associated with signs of murine ocular toxicity, and did not interfere with pre-existing retinal vasculature or retinal function. SH-11037 synergized with anti-VEGF therapy in vitro and in vivo, suggesting a VEGFindependent mechanism. By photoaffinity pulldown, I identified soluble epoxide hydrolase (sEH) as an SH-11037-binding target. sEH is a key enzyme in ω-3 and ω-6 fatty acid metabolism. sEH levels were dramatically upregulated in retinal sections from L-CNV mice and a specific sEH inhibitor, t-AUCB, significantly suppressed L-CNV lesion volume. Additionally, SH-11037 inhibited sEH enzymatic activity in vitro and in vivo in L-CNV mice. Given the role of sEH in the metabolism of docosahexaenoic acids (DHA), inhibition of sEH using small molecules like SH-11037 would enhance ocular DHA levels, with beneficial antiangiogenic and anti-inflammatory effects. SH-11037 is thus a novel sEH inhibitor, which could make it an alternative or additive therapy to existing anti- VEGF drugs for treatment of neovascular diseases in the eye and other tissues.