Tse, Ho Man. / Thesis (M.Phil)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 166-173). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / 撮要 --- p.v / Table of Content --- p.vi / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Basis of Prostate Cancer --- p.1 / Chapter 1.1.1 --- Epidemiology and Risk Factors of Prostate Cancer --- p.1 / Chapter 1.1.2 --- Pathology of Prostate Cancer --- p.2 / Chapter 1.1.3 --- Treatment Approaches for Prostate Cancer --- p.4 / Chapter 1.2 --- Sex Hormones and Prostate Cancer --- p.7 / Chapter 1.2.1 --- Prostate Development --- p.7 / Chapter 1.2.2 --- Involvement of Sex Hormones in Prostate Cancer --- p.8 / Chapter 1.2.3 --- Molecular Mechanisms of Sex Hormones --- p.13 / Chapter 1.2.4 --- Hormone Receptor Antagonists --- p.15 / Chapter 1.3 --- Involvement of microRNAs in Cancer --- p.19 / Chapter 1.3.1 --- Basis of microRNAs --- p.19 / Chapter 1.3.2 --- Aberrant microRNA Expressions in Cancers --- p.23 / Chapter 1.3.3 --- Current Understandings on Regulations of micro RN A Expressions --- p.26 / Chapter 1.3.4 --- Regulation of miRNA Expressions by Hormones --- p.29 / Chapter 1.4 --- "Effects of the Anti-estrogen ICI 182,780 on Prostate Cancer Cells" --- p.30 / Chapter 1.4.1 --- "ICI 182,780 Inhibits Cell Growth ofDU145" --- p.30 / Chapter 1.5 --- Objectives of Project --- p.32 / Chapter Chapter 2: --- Materials --- p.34 / Chapter 2.1 --- Bacteria Strain --- p.34 / Chapter 2.2 --- Tissue Culture Media --- p.34 / Chapter 2.3 --- Plasmids --- p.34 / Chapter 2.4 --- Kits and Accessories --- p.35 / Chapter 2.5 --- Reagents and Solutions --- p.36 / Chapter 2.6 --- DNA Oligos --- p.38 / Chapter 2.7 --- Equipments --- p.40 / Chapter Chapter 3: --- Methods --- p.41 / Chapter 3.1 --- Cell Culture Conditions --- p.41 / Chapter 3.2 --- miRNA Expression Profiling of DU145 --- p.41 / Chapter 3.2.1 --- RNA Isolation --- p.41 / Chapter 3.2.2 --- miRNA Microarray Profiling ofDU145 : --- p.42 / Chapter 3.2.2.1 --- Fluorescent Labeling of RNA and Microarray Hybridization --- p.42 / Chapter 3.2.2.2 --- Scanning and Analysis of Signals --- p.46 / Chapter 3.2.3 --- Confirming miR-765 Up-regulation by ICI with qRT-PCR --- p.46 / Chapter 3.2.3.1 --- Assessing ERp Dependency in miR-765 Induction --- p.48 / Chapter 3.2.4 --- Effects of ICI on ARHGEF11 Expression --- p.49 / Chapter 3.2.4.1 --- Reverse Transcription of mRNA --- p.50 / Chapter 3.2.4.2 --- Quantitative Real-Time PCR for Gene mRNA expression --- p.50 / Chapter 3.3 --- Characterizing the Promoter Region of miR-765 --- p.52 / Chapter 3.3.1 --- Cloning of miR-765 Promoter into pGL3-Basic Vector --- p.52 / Chapter 3.3.1.1 --- PCR Amplification of miR-765 Putative Promoter Region --- p.52 / Chapter 3.3.1.2 --- Ligation of the Amplified Regions in pGL3-Basic Vector --- p.55 / Chapter 3.3.1.3 --- Transformation and Screening of pGL3-765 Plasmid --- p.57 / Chapter 3.3.1.4 --- Preparation of pGL3-765 Plasmid DNA --- p.59 / Chapter 3.3.2 --- Preparation of Truncated miR- 765 Promoter Clones --- p.60 / Chapter 3.3.2.1 --- pGL3-765-Trunc#l --- p.61 / Chapter 3.3.2.2 --- pGL3-765-Trunc#2 --- p.62 / Chapter 3.3.2.3 --- pGL3-765-Trunc#3 --- p.62 / Chapter 3.3.3 --- Assessing the miR- 765 Promoter Activities --- p.63 / Chapter 3.3.3.1 --- Optimizing Transfection Conditions --- p.64 / Chapter 3.3.3.2 --- Co-transfection of pGL3-765 and pRL-CMV into DU145 Cells.. --- p.64 / Chapter 3.3.3.3 --- Measuring Luciferase Activities --- p.65 / Chapter 3.3.4 --- Computational Prediction of Transcription Factor Binding Sites on miR-765 Promoter --- p.66 / Chapter 3.4 --- Characterizing the Promoter Region of ARHGEF11.. --- p.67 / Chapter 3.4.1 --- Cloning of ARHGEF11 Promoter into pGL3-Basic Vector (pGL3-ARH) --- p.67 / Chapter 3.4.1.1 --- PCR Amplification of ARHGEF11 Putative Promoter Region --- p.67 / Chapter 3.4.1.2 --- Ligation of the Amplified Regions in pGL3-Basic Vector --- p.68 / Chapter 3.4.1.3 --- Preparation of Plasmid DNA --- p.69 / Chapter 3.4.2 --- Preparation of Truncated ARHGEF11 Promoter Clones --- p.69 / Chapter 3.4.2.1 --- pGL3-ARH-Trunc#l --- p.69 / Chapter 3.4.2.2 --- pGL3-ARH-Trunc#2 --- p.70 / Chapter 3.4.2.3 --- pGL3-ARH-Trunc#3 --- p.71 / Chapter 3.4.3 --- Assessing ARHGEF11 Promoter Activities --- p.72 / Chapter 3.5 --- Identifying Transcription Factor Binding Sites on ARHGEF11 Promoter with EMS A --- p.73 / Chapter 3.5.1 --- Computational Prediction --- p.73 / Chapter 3.5.2 --- Preparation of Biotinylated Probe for use in EMSA --- p.73 / Chapter 3.5.3 --- Preparation of Specific Competitors --- p.74 / Chapter 3.5.4 --- Preparation of DU145 Nuclear and Cytoplasmic Extracts --- p.75 / Chapter 3.5.4.1 --- Preparation of Extracts --- p.75 / Chapter 3.5.4.2 --- Measuring Protein Concentrations --- p.76 / Chapter 3.5.5 --- EMSA Detection of Interaction between Protein and Probe --- p.76 / Chapter 3.6 --- Assessing Biological Significances of miR-765 --- p.78 / Chapter 3.6.1 --- Effects of ICI on DU145 Cells Growth --- p.79 / Chapter 3.6.2 --- Effects of ICI on DU145 Migration Ability --- p.79 / Chapter 3.6.2.1 --- Monolayer Wound Healing Assay --- p.79 / Chapter 3.6.2.2 --- Transwell Migration Assay --- p.80 / Chapter 3.6.3 --- Validating Functionality of Ectopic miR- 765 --- p.81 / Chapter 3.6.3.1 --- miR-765 Recognition Sequence --- p.81 / Chapter 3.6.3.2 --- Preparation of pMIR-765 vector --- p.82 / Chapter 3.6.3.3 --- Ectopic Introduction of miR-765 into DU145 Cells --- p.84 / Chapter 3.6.3.4 --- "Verifying Functionality, of Ectopic miR-765" --- p.84 / Chapter 3.6.4 --- Effects of miR-765 on DU145 Growth --- p.86 / Chapter 3.6.5 --- Effects of miR-765 on DU145 Migration Ability --- p.86 / Chapter 3.7 --- Statistical Analysis --- p.87 / Chapter Chapter 4: --- Results --- p.88 / Chapter 4.1 --- "Identifying ICI 182,780-Regulated miRNA in DU145 Cells" --- p.88 / Chapter 4.1.1 --- miRNA Expression Profiling of DU145 with Microarray --- p.88 / Chapter 4.1.2 --- "Confirming Induction of miR-765 by ICI 182,780 with qRT-PCR" --- p.91 / Chapter 4.1.3 --- "ARHGEF11, Host Gene of miR-765" --- p.95 / Chapter 4.1.4 --- "Induction of ARHGEF 11 by ICI 182,780" --- p.96 / Chapter 4.2 --- Characterization miR-765 Promoter Region --- p.98 / Chapter 4.2.1 --- Cloning of miR- 765 Promoter Region into pGLS-Basic Vector --- p.98 / Chapter 4.2.2 --- Promoter Activity of miR-765 Promoter --- p.100 / Chapter 4.2.3 --- Deletion Mapping of miR- 765 Promoter Region --- p.102 / Chapter 4.2.4 --- Promoter Activities and Inducibitiy of Truncated miR-765 Promoters --- p.103 / Chapter 4.2.5 --- Computational Prediction of Transcription Factor Binding Sites on miR-765 Promoter --- p.105 / Chapter 4.3 --- Characterization of ARHGEF 11 Promoter Region --- p.107 / Chapter 4.3.1 --- Cloning of ARHGEF 11 Promoter --- p.107 / Chapter 4.3.2 --- Promoter Activitiy of ARHGEFll Promoter --- p.109 / Chapter 4.3.3 --- Deletion Mapping of ARHGEFll Promoter --- p.111 / Chapter 4.3.4 --- Promoter Activities and Inducibitiy of Truncated ARHGEF 11 Promoters --- p.113 / Chapter 4.4 --- Identifying Transcription Factor Binding Sites on ARHGEF 11 Promoter --- p.115 / Chapter 4.4.1 --- Computational Prediction of Transcription Factor Binding Sites onARHGEFll Promoter --- p.115 / Chapter 4.4.2 --- Preparation of Probe and Specific Competitors for EMSA --- p.117 / Chapter 4.4.3 --- Interaction between DU145 Nuclear Extract and ARHGEF 11 Promoter Region --- p.119 / Chapter 4.5 --- Biological Significances of miR-765 --- p.122 / Chapter 4.2.1 --- "Effects of ICI 182,780 on DU145 Cell growth" --- p.122 / Chapter 4.2.2 --- "Effects of ICI 182,780 on DU145 Cell Migration" --- p.124 / Chapter 4.2.3 --- Verifying Functionality of Ectopic miR-765 --- p.131 / Chapter 4.2.4 --- Effects of miR-765 on DU145 Cell Growth --- p.133 / Chapter 4.2.5 --- Effects of miR-765 on DU145 Cell Migration --- p.135 / Chapter Chapter 5: --- Discussion --- p.138 / Chapter 5.1 --- "Identifying miR-765 as an Up-regulated miRNA by ICI 182,780" --- p.139 / Chapter 5.1.1 --- "Information about ICI 182,780" --- p.139 / Chapter 5.1.2 --- miRNA Profiling of DU145 --- p.139 / Chapter 5.1.3 --- "Confirming Induction of miR-765 by ICI 182,780 and ERβ dependency with qRT-PCR" --- p.140 / Chapter 5.1.4 --- "Up-regulation of miR-765 Host Gene, ARHGEF11, by ICI" --- p.141 / Chapter 5.2 --- Regulatory Elements of miR-765 Expression --- p.143 / Chapter 5.2.1 --- Own Upstream promoter of miR- 765 --- p.144 / Chapter 5.2.2 --- Promoter of Host Gene ARHGEF11 --- p.146 / Chapter 5.2.3 --- Interaction between ARHGEF11 Promoter Critical Region and Transcription Factors --- p.147 / Chapter 5.2.4 --- Involvement of independent Promoter and Host Gene Promoter in miR-765 Regulation --- p.757 / Chapter 5.3 --- Biological Significances of miR-765 on DU145 --- p.153 / Chapter 5.4 --- Significance of Findings and Future Studies --- p.158 / Chapter 5.4.1 --- Clinical Significance --- p.158 / Chapter 5.4.2 --- Future Studies --- p.161 / Chapter Chapter 6: --- Conclusion --- p.163 / Chapter Chapter 7: --- References --- p.166

by Ng Ping-chung. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 161-179). / List of Abbreviation / Abstract / Acknowledgements / Table of contents / Chapter 1. --- Introduction / Chapter 1.1 --- Hormone and carcinogenesis --- p.1 / Chapter 1.2 --- Estrogen and carcinogenesis --- p.3 / Chapter 1.2.1 --- Carcinogenesis and endogenous sex hormone status --- p.3 / Chapter 1.2.2 --- Etiology of breast cancer --- p.3 / Chapter 1.2.2.1 --- Epidemiology --- p.3 / Chapter 1.2.2.2 --- Hormonal factors --- p.5 / Chapter 1.2.2.3 --- Genetic predisposition --- p.8 / Chapter 1.2.2.4 --- Influence of diet --- p.8 / Chapter 1.2.3 --- Hormonal therapy --- p.18 / Chapter 1.2.3.1 --- Anti-estrogen --- p.18 / Chapter 1.2.3.2 --- Progestins --- p.21 / Chapter 1.2.3.3 --- Aromatase inhibitor --- p.22 / Chapter 1.2.3.4 --- GnRH analogue therapy --- p.26 / Chapter 1.3 --- Estrogen pool --- p.26 / Chapter 1.4 --- Estrogen receptor --- p.30 / Chapter 1.4.1 --- General features of estrogen receptor and action mechanism --- p.30 / Chapter 1.4.2 --- Anti-estrogen binding site (AEBS) --- p.31 / Chapter 1.4.3 --- Physiological consideration --- p.32 / Chapter 1.4.3.1 --- Uterus: uterotrophic responses --- p.32 / Chapter 1.4.3.2 --- "Progesterone, the physiological estrogen antagonist" --- p.34 / Chapter 1.5 --- The role of growth factors and steroid hormones in breast cancer cell --- p.35 / Chapter 1.6 --- Alternate cytotoxic action of TAM --- p.37 / Chapter 1.7 --- In vitro models utilised in breast cancer study --- p.38 / Chapter 1.8 --- Current development of anti-estrogen --- p.39 / Chapter 1.9 --- Background about yuehchukene (YCK) --- p.41 / Chapter 2. --- Materials and methods / Chapter 2.1 --- Studies using whole animals --- p.47 / Chapter 2.1.1 --- Uterotrophic assay in rats --- p.47 / Chapter 2.1.2 --- Anti-implantation assay in rats --- p.48 / Chapter 2.1.3 --- Vaginal smear in mice --- p.49 / Chapter 2.2 --- Studies using breast cancer cells --- p.49 / Chapter 2.2.1 --- MCF-7 cell culture --- p.49 / Chapter 2.2.1.1 --- Measurement of cell number --- p.50 / Chapter 2.2.1.1.1 --- Cell count with haemocytometer --- p.50 / Chapter 2.2.1.1.2 --- Cell number estimated by DNA content in culture using Hoechst33258 --- p.51 / Chapter 2.2.1.1.3 --- Cell number estimated by [3H]-thymidine incorporation --- p.52 / Chapter 2.2.1.1.4 --- Preparation of dextran coated charcoal stripped serum --- p.52 / Chapter 2.2.2 --- MDA-MB-231 cell culture --- p.53 / Chapter 2.3 --- Studies using steroid receptors --- p.54 / Chapter 2.3.1 --- Rat uterine estrogen receptor --- p.54 / Chapter 2.3.2 --- Mice uterus and vaginal estrogen receptor --- p.55 / Chapter 2.3.3 --- MCF-7 cell estrogen receptor --- p.55 / Chapter 2.3.3.1 --- MCF-7 whole cell estrogen receptor binding --- p.55 / Chapter 2.3.3.2 --- Cytosolic estrogen receptor preparation from MCF-7 cell --- p.57 / Chapter 2.3.4 --- Progesterone receptor binding in MCF-7 cell --- p.57 / Chapter 2.3.5 --- Rat hepatic anti-estrogen binding site (AEBS) --- p.58 / Chapter 2.3.6 --- Estrogen receptor content estimation by enzyme immunoassay --- p.58 / Chapter 2.4 --- Enzyme studies related to estrogen metabolism --- p.60 / Chapter 2.4.1 --- Rat uterine ornithine decarboxylase (ODC) --- p.60 / Chapter 2.4.2 --- Rat hepatic ethoxyresorufin O-deethylase (EROD) --- p.60 / Chapter 2.4.3 --- Rat hepatic estradiol-2-hydroxylase --- p.62 / Chapter 2.4.4 --- MCF-7 cell estradiol-2-hydroxylase --- p.62 / Chapter 2.4.5 --- Human placental microsomal aromatase activity --- p.63 / Chapter 2.5 --- Enzymatic studies related to signal transduction --- p.64 / Chapter 2.5.1 --- Inhibition of Protein Kinase C activity of MCF-7 cell and protein phosphorylation --- p.64 / Chapter 2.5.2 --- Inhibition of calmodulin activation of cyclic nuleotide phosphodiesterase --- p.66 / Chapter 2.6 --- "Preparation of Pre-YCK, crude-YCK and post-YCK fractions" --- p.67 / Chapter 2.7 --- Preparation of Indole-3-carbinol acid condensation product (I3Ca) --- p.71 / Chapter 2.8 --- Studies on TCP series of YCK analogues --- p.71 / Chapter 2.9 --- List of test compounds --- p.75 / Chapter 2. 10 --- List of radio-ligands --- p.77 / Chapter 2.11 --- Miscellaneous reagents related to cell culture --- p.78 / Chapter 2.11.1 --- Culture medium --- p.78 / Chapter 2.11.2 --- Fetal calf serum --- p.78 / Chapter 2.11.3 --- Penicillin-streptomycin powder --- p.78 / Chapter 2.11.4 --- Phosphate buffer saline --- p.78 / Chapter 2.12 --- "Solvents, chemical and scintillants" --- p.78 / Chapter 3. --- Result / Chapter 3.1 --- Rat uterotrophic response with EE2 and YCK --- p.80 / Chapter 3.2 --- Mice vaginal cornification with estradiol (E2) and YCK --- p.83 / Chapter 3.3 --- Human breast cancer cell culture --- p.86 / Chapter 3.3.1 --- MCF-7 cell growth with YCK --- p.86 / Chapter 3.3.2 --- MCF-7 cell growth with YCK analogues and other related compounds --- p.91 / Chapter 3.3.3 --- MDA-MB-231 cell culture --- p.100 / Chapter 3.4 --- Receptor Binding --- p.100 / Chapter 3.4.1 --- Rat uterine estrogen receptor --- p.100 / Chapter 3.4.2 --- Mice uterine and vaginal estrogen receptor --- p.103 / Chapter 3.4.3 --- MCF-7 whole cell and cytosolic estrogen receptor --- p.103 / Chapter 3.4.4 --- MCF-7 cell progesterone receptor --- p.107 / Chapter 3.4.5 --- Rat hepatic anti-estrogen binding sites (AEBS) --- p.111 / Chapter 3.5 --- Enzyme activities related to estrogen metabolism --- p.111 / Chapter 3.5.1 --- Rat uterine ornithine decarboxylase (ODC) --- p.111 / Chapter 3.5.2 --- Rat hepatic estradiol-2-hydroxylase and ethoxyresorufin O-deethylase --- p.114 / Chapter 3.5.3 --- MCF-7 cell estradiol-2-hydroxylase --- p.121 / Chapter 3.5.4 --- Human placenta and MCF-7 cell aromatase --- p.126 / Chapter 3.6 --- Enzyme activities related to signal transduction --- p.126 / Chapter 3.6.1 --- Protein kinase C inhibition in vitro --- p.126 / Chapter 3.6.2 --- Calmodulin-dependent phosphodiesterase inhibitory actions in vitro --- p.131 / Chapter 3.7 --- Studies on TCP series of YCK analogues --- p.131 / Chapter 4. --- Discussion / Chapter 4.1 --- Estrogenicity of YCK --- p.140 / Chapter 4.2 --- Estrogenicity of YCK correlates with estrogen receptor (ER) binding --- p.141 / Chapter 4.3 --- Attenuation by YCK --- p.142 / Chapter 4.3.1 --- Attenuation by YCK on estrogen induced uterotrophic activity --- p.142 / Chapter 4.3.2 --- Attenuation by YCK on mice vaginal cornification with estradiol and YCK --- p.142 / Chapter 4.3.3 --- Attenuation by YCK on MCF-7 cell growth --- p.143 / Chapter 4.3.4 --- Attenuation of YCK on ornithine decarboxylase (ODC) induced by estrogen --- p.144 / Chapter 4.4 --- Deviation between YCK potency and RBA --- p.145 / Chapter 4.5 --- Estrogen inhibition action of YCK via non receptor binding mechanism --- p.148 / Chapter 4.6 --- Protein kinase C/ calmodulin-dependent phosphodiesterase inhibitor --- p.152 / Chapter 4.7 --- Progesterone receptor --- p.154 / Chapter 4.8 --- Aromatase inhibitor? --- p.155 / Chapter 4.9 --- Posssible mechanism for the attenuation of estrogenic action by YCK --- p.157 / Chapter 4.10 --- TCP series of YCK analogues --- p.158 / Chapter 4.11 --- Future works --- p.159 / Chapter 5. --- Reference --- p.161 / Appendix / Appendix 1 YCK analogues / Appendix 2 Structure of compounds mentioned in this thesis

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.

Tamoxifen is an effective anti-estrogen for treatment of women with hormonedependent breast cancer but acquired drug resistance limits its therapeutic benefit. We have previously reported that expression of active Akt3 in MCF-7 breast cancer cells results in estrogen-independent tumors that are actually stimulated to grow after tamoxifen treatment. We hypothesize that this tamoxifen resistance may be attributed to binding of different co-regulator proteins and/or different binding affinity of these proteins to the estrogen receptor in M CF-7 cells overexpressing active Akt3 as compared to parental MCF-7 cells. We have immuno-precipitated the estrogen receptor along with bound co-regulator proteins in both cells lines after tamoxifen, estradiol, or vehicle treatment. After 2-D gel electrophoresis separation of these immuno-precipitated proteins and comparing them using PDQuest 2-D analysis software, we identified protein spots that were statistically different under the treatment conditions between the two cell lines. The isolated protein spots were subjected to MALDI-TOF mass spectrometry. By searching protein databases through the MASCOT website for protein identification, we have identified estrogen receptor co-regulator proteins that may play a potential role in tamoxifen resistance. Current studies are focused on addressing the role of differential protein binding as a possible mechanism of tamoxifen resistance in Akt3 over-expressing breast cancer cells.

Indiana University-Purdue University Indianapolis (IUPUI) / Breast cancer remains the most prevalent malignancy diagnosed in women. More than two thirds of all diagnosed breast cancers are estrogen receptor (ER)-positive and are dependent on estrogen signaling. Drugs for the treatment of ER-positive breast cancer can be divided into three classes: selective estrogen receptor modulators (SERMs), selective estrogen receptor down-regulators (SERDs) and aromatase inhibitors (AIs). However, the efficacy and safety of SERMs, SERDs and AIs are compromised by side effects or tumor resistance. One possible way of improving treatment efficacy and safety profiles is to develop agents with dual aromatase inhibitory and ER modulatory activity. Over the past 30 years, tamoxifen, a SERM, has become the most widely used drug for the adjuvant treatment of breast cancer. The metabolism of tamoxifen has a complex profile involving both active and inactive metabolites, among which endoxifen, 4-hydroxytamoxifen (4-HT) and norendoxifen (Nor) have been shown to have ER modulatory activity. Previous studies have also shown that norendoxifen is a potent AI in vitro. These preliminary studies support the utilization of tamoxifen metabolites as lead compounds for the development of dual AI/SERM(D) agents. Hydroxynorendoxifen (Hdn) was identified as a novel tamoxifen metabolite, with an average plasma concentration of 0.82 nM. Nor and Hdn were potent and relatively selective AIs, with Kis of 70 nM and 20 nM, respectively. Nor and Hdn have high binding affinity for ER-α and ER-β, with EC50 values less than 35 nM. Nor and Hdn can inhibit breast cancer cell proliferation with high potency, with IG50s of 25 nM and 9 nM, respectively. Nor and Hdn can suppress progesterone receptor (PGR) mRNA expression level by reducing it by 68% and 86%. Moreover, a series of Nor analogues were shown to have both potent aromatase inhibitory activity and high ERs binding affinity. Results from this dissertation will contribute to three aspects: 1) the identification of Hdn as a tamoxifen metabolite illustrated a more comprehensive metabolism profile of tamoxifen; 2) the data suggest Nor and Hdn possess dual aromatase inhibitory and ER antagonistic activity; 3) a series of Nor analogues were characterized as lead compounds for the development of dual AI/SERM(D) agents.

Our lab has previously reported the identification of a novel endogenous 19-nor steroid, estradienolone (ED), in pregnant women that strongly bound to sex hormone binding globulin. Estrogen-receptor related receptors (ERRs), which have no known natural ligands, are a family of orphan receptors consisting of 3 isoforms: ERRalpha, ERRbeta and ERRgamma. The ERRs have been shown to actively modulate estrogenic responses, to play an essential role in pregnancy, and are implicated in breast cancer prognosis. My results show that ED acts as an antagonist of the ERRalpha confirming preliminary results obtained by our group. Studies of cellular responses demonstrate that ED has strong anti-mitogenic properties. ED inhibited the growth of both estrogen receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) breast cancer cells in a dose-dependent manner but did not have any effects on the proliferation of the non-cancerous immortalized epithelial breast MCF-10A cells. The finding that ED inhibits proliferation of both ER negative and ER positive breast cancer cells, and regulate ERR transcriptional activity may have important ramifications in breast cancer therapy.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Aromatase inhibitors (AIs) are the current standard of care for the treatment of hormone receptor positive breast cancer in postmenopausal women. Nearly one-half of patients receiving AI therapy develop musculoskeletal toxicity that is characterized by joint and/or muscle pain and approximately one-fourth of patients discontinue their therapy as a result of musculoskeletal pain. Since there are no effective strategies for prevention or treatment, insight into the mechanisms of AI-induced pain is critical to improve treatment. However, there are few studies of AI effects in animal models of nociception. To determine whether AIs produce hypersensitivity in animal models of pain, I examined the effects of AI administration on mechanical, thermal, and chemical sensitivity in rats. The results demonstrate that (1) repeated injection of 5 mg/kg letrozole in male rats produces mechanical, but not thermal, hypersensitivity that extinguishes when drug dosing is stopped; (2) administering a single dose of 1 or 5 mg/kg letrozole in ovariectomized (OVX) rats also induces mechanical hypersensitivity, without altering thermal sensitivity and (3) a single dose of 5 mg/kg letrozole or daily dosing of letrozole or exemestane in male rats augments flinching behavior induced by intraplantar ATP injection. To determine whether the effects of AIs on nociceptive behaviors are mediated by activation or sensitization of peptidergic sensory neurons, I determined whether letrozole exposure alters release of calcitonin gene-related peptide (CGRP) from isolated rat sensory neurons and from sensory nerve endings in rat spinal cord slices. No changes in basal, capsaicin-evoked or high extracellular potassium-evoked CGRP release were observed in sensory neuronal cultures acutely or chronically exposed to letrozole. Furthermore, letrozole exposure did not alter the ability of ATP to augment CGRP release from sensory neurons in culture. Finally, chronic letrozole treatment did not augment neuropeptide release from spinal cord slices. Taken together, these results do not support altered release of this neuropeptide into the spinal cord as mediator of letrozole-induced mechanical hypersensitivity and suggest the involvement of other mechanisms. Results from this dissertation provide a new experimental model for AI-induced hypersensitivity that could be beneficial in delineating mechanisms mediating pain during AI therapy.