Because of the structural resemblance to the female hormone, phytoestrogen is another important class of endocrine disruptor. In the present project, we evaluated the effects of phytoestrogens isoliquiritigenin (ILN), hesperetin (HES), genistein, (GEN) and naringenin (NAR) on estrogen metabolism and also their effects on MCF-7 tumor growth in ovariectomized nude mice. We found that these phytoestrogens had differential effect on MCF-7 xenografts. NAR and GEN had totally different responses in the tumor growth. In contrast, ILN and HES only deterred MCF-7 xenograft growth when CYP19 was overexpressed in the graft. / Breast cancer is one of the most prevalent female cancers in Hong Kong and western countries. Prolonged exposure to estrogen has been associated with increased risk of breast cancer. Many enzymes are responsible for estrogen metabolism, for instance, aromatase (CYP19) is responsible for biosynthesis; CYP1 family enzymes hydroxylate estrogen; COMT (catechol-O-methyltransferase) inactivates the hydroxyestrogen; and UDP-glucuronosyltransferase 1A1 (UGT1A1) eliminates the estrogen metabolites. In this project, we employed cell and animal models to address estrogen metabolism-related questions under the influence of endocrine disruptors. / TCDD is a prototype compound of a whole class of halogenated aromatic hydrocarbons termed dioxin-like contaminants, which are also known to be endocrine disruptors. Because of their persistence in the environment dioxins are one of the most concerned classes of carcinogens. Humans can be exposed to this pollutant through contaminated food, air, drinking water, etc. We found that pre-ovariectomy administration of TCDD could significantly reduce aromatase expression in the brain but increase the expression in the adipose tissue. Our results suggested that the timing of exposure to the toxicant could determine the estrogenicity of TCDD. / The present project indicated that endocrine disruptors can alter the metabolism of estrogen; however, the significance of this alteration may be specific to tissues' phenotype and the timing of exposure. / Ye Lan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 169-192). / 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.

Thesis (M.D. with Distinction in Research) -- University of Texas Southwestern Medical Center at Dallas, 2006. / Partial embargo. Vita. Bibliography: 44-46

Yuen Mong Ting. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 155-169). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (English) --- p.ii / Abstract (Chinese) --- p.v / Contents --- p.vi / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Developmental biology of the prostate --- p.1 / Chapter 1.1.1 --- Development of the prostate gland in humans and rodents --- p.1 / Chapter 1.1.2 --- Mesenchymal-epithelial interaction --- p.2 / Chapter 1.2 --- Overview of the endocrinology of prostate --- p.3 / Chapter 1.3 --- Estrogen in male and prostate gland --- p.4 / Chapter 1.3.1 --- Stimulating effect of estrogen on prostate gland --- p.4 / Chapter 1.3.2 --- Inhibitory effect of estrogen on prostate gland --- p.5 / Chapter 1.4 --- Study of the role of estrogen receptors in prostate gland with the use of estrogen receptor knockout mice --- p.6 / Chapter 1.4.1 --- The two isoforms of estrogen receptors (ER): ERα and ERβ --- p.6 / Chapter 1.4.2 --- The use of estrogen receptor knockout mice for the study of ER --- p.7 / Chapter 1.5 --- Estrogen as a carcinogen --- p.8 / Chapter 1.5.1 --- Formation of DNA adducts --- p.8 / Chapter 1.5.2 --- Formation of oxidants --- p.9 / Chapter 1.5.3 --- Estrogen as a microtubule-disrupting agent --- p.10 / Chapter 1.6 --- Estrogen carcinogenicity in animal models --- p.11 / Chapter 1.6.1 --- Syrian golden hamster model --- p.11 / Chapter 1.6.2 --- Rat model --- p.12 / Chapter 1.7 --- Animal models of prostate cancer by hormonal induction --- p.12 / Chapter 1.7.1 --- Canine model --- p.13 / Chapter 1.7.2 --- Noble rat model --- p.13 / Chapter 1.7.3 --- Sprague-Dawley rat model --- p.15 / Chapter 1.7.4 --- Wistar and F344 rat model --- p.15 / Chapter 1.8 --- Perinatal estrogen exposure and prostate development --- p.16 / Chapter 1.8.1 --- Prenatal estrogen exposure --- p.15 / Chapter 1.8.2 --- Neonatal estrogen exposure --- p.17 / Chapter 1.9 --- Therapeutic use of synthetic estrogen --- p.18 / Chapter 1.9.1 --- Use of diethylstilbestrol in treating prostate cancer --- p.18 / Chapter 1.9.2 --- Use of diethylstilbestrol during pregnancy --- p.19 / Chapter 1.10 --- Estrogen contamination in food --- p.20 / Chapter 1.10.1 --- Estrogen in milk and dairy products --- p.20 / Chapter 1.10.2 --- Estrogen in meat --- p.21 / Figure 1.1 --- p.23 / Chapter Chapter 2. --- Materials and methods --- p.25 / Chapter 2.1 --- In vitro study of estrogen carcninogenicity in normal prostatic cell line --- p.25 / Chapter 2.1.1 --- NRP-152 cell line --- p.25 / Chapter 2.1.2 --- In vitro estrogen treatment on NRP-152 cells --- p.25 / Chapter 2.1.3 --- Colony formation by soft agar assay --- p.27 / Chapter 2.1.4 --- Determination of growth parameters of estrogen-treated and untreated NRP-152 cells --- p.29 / Chapter 2.1.5 --- Gene expression profiling in estrogen-transformed and untreated parental NRP-152 cells by cDNA microarray --- p.30 / Chapter 2.1.6 --- Immunohistochemistry of cultured cells --- p.34 / Chapter 2.1.7 --- Immunofluorescence on cultured cells --- p.36 / Chapter 2.1.8 --- Electron microscopy of the estrogen-transformed and untreated parental NRP-152 cells --- p.37 / Chapter 2.1.9 --- Tumorigenicity in nude mice --- p.38 / Chapter 2.1.10 --- Protein expressions and Western blottings in estrogen-transformed and untreated parental NRP-152 cells --- p.39 / Chapter 2.2 --- In vivo study of estrorgen carcinogenicity in rat protstate gland --- p.41 / Chapter 2.2.1 --- Origin and supply of Noble rats --- p.41 / Chapter 2.2.2 --- Perinatal estrogen imprinting on male Noble rats with diethylstilbestrol --- p.42 / Chapter 2.2.3 --- Long-term hormonal treatment with sex steroids on male Noble rats at adulthood --- p.43 / Chapter 2.2.4 --- Morphological study of Noble rat prostates --- p.44 / Chapter 2.2.5 --- Protein expressions by immunohistochemistry in estrogen-primed and hormone-treated Noble rat prostates --- p.45 / Tables 2.1 -2.2 --- p.48 / Chapter Chapter 3. --- Results --- p.50 / Chapter 3.1 --- In vitro study --- p.50 / Chapter 3.1.1 --- Dose selection for estrogen treatment of NRP-152 cells from cell proliferation assay --- p.50 / Chapter 3.1.2 --- Colony formation in soft agar --- p.50 / Chapter 3.1.3 --- Morphology of NRP-152 cells and the estrogen-transformed clones --- p.51 / Chapter 3.1.4 --- Study of growth parameters --- p.52 / Chapter 3.1.5 --- CDNA array analysis of differentia] gene pattern --- p.53 / Chapter 3.1.6 --- Immunohistochemistry of untreated parental and estrogen- transformed NRP-152 cells --- p.55 / Chapter 3.1.7 --- Electron microscopy --- p.58 / Chapter 3.1.8 --- Tumorigenicity of NRP-152 cells and the estrogen-transformed clones --- p.59 / Chapter 3.1.9 --- Western blottings --- p.59 / Chapter 3.2 --- In vivo study --- p.52 / Chapter 3.2.1 --- Survival of male Nobel rats during perinatal and long-term hormone treatment --- p.62 / Chapter 3.2.2 --- Histological studies of Noble rat prostates --- p.63 / Chapter 3.2.3 --- Immunohistochemistry of the hormone-treated and control Noble rat prostates --- p.65 / Figure 3.1.1 -3.1.44 --- p.73 / Figure 3.2.1 - 3.2.50 --- p.97 / Table 3.1 -3.4 --- p.117 / Chapter Chapter 4. --- Discussions --- p.121 / Chapter 4.1 --- The study on the transformation of cells and soft agar assay --- p.121 / Chapter 4.2 --- Growth patterns of the estrogen-transformed clones --- p.123 / Chapter 4.3 --- Altered differential gene expression --- p.124 / Chapter 4.3.1 --- TUBA --- p.124 / Chapter 4.3.2 --- PTEN --- p.125 / Chapter 4.3.3 --- RAP 1A --- p.126 / Chapter 4.3.4 --- BRCA2 --- p.126 / Chapter 4.4 --- Ultrastructural study in the estrogen-transformed and untreated parental NRP-152 cells --- p.127 / Chapter 4.5 --- Neoplastic lesions induced in prostates of estrogen-imprinted and long-term combined hormone treated Noble rats --- p.129 / Chapter 4.6 --- Altered protein expressions in estrogen-transformed NRP-152 cells and estrogen-imprinted and hormone-treated Noble rat prostates --- p.132 / Chapter 4.6.1 --- Alteration in steroid hormone receptors --- p.132 / Chapter 4.6.2 --- Alternation in cytoskeleton (tubulin-α) --- p.138 / Chapter 4.6.3 --- Alternation in PTEN --- p.141 / Chapter 4.6.4 --- Alternation in Rap1 --- p.143 / Chapter 4.6.5 --- Alternation in BRCA2 --- p.145 / Chapter 4.6.6 --- "Altered in scavenger enzyme (Superoxide dismutase, SOD-1)" --- p.147 / Chapter Chapter 5. --- Summary --- p.150 / Reference --- p.155