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Class of 2009 Abstract / OBJECTIVES: To develop a novel characterization system utilizing immunofluorescent FLAG tagged EP2 and EP4 receptors to assist in the explanation of their unique cell signaling properties for exploitation in future drug development design. METHODS: Plasmids were obtained and isolated that contained cDNAs encoding FLAG-tagged EP2 and EP4 receptors for transient expression in HEK-293 cells. The sequences of these plasmids were confirmed by restriction enzyme analysis and DNA sequencing. Transfected cells were treated with vehicle, PGE2 or forskolin to assess appropriate receptor functionality based on cAMP induction. RESULTS: The two PGE2 receptor subtypes, EP2 and EP4, are similar in their activation of adenylyl cyclase (AC) and subsequent up regulation of cAMP production. These receptors differ, however, in that EP2 more efficiently stimulates cAMP production and EP4 signaling involves the activation of phosphatidylinositol 3-kinase (PI3K) and extracellular signal related kinases (ERKs). The PGE2- treated cells responded as predicted with intracellular production of cAMP, with the EP2 receptor responding more efficiently than the EP4 receptor. CONCLUSIONS: The intent is for these cells to be used as a novel assay system for the development of future selective EP2 and EP4 agonists. This research could potentially benefit in selectively targeting EP2 or EP4 pathways linked to prevalent ailments such as pain, fever, inflammation, possibly cancer or bone growth.

This dissertation mainly discussed the investigation of five different soft corals collected in Green Island and one soft coral collected in Kenting. They were identified as Clavularia viridis, Xenia florida, Cespitularia taeniata, Cespitularia hypotentaculata, and Sarcophyton stolidotum. In the isolation of these corals, there were sixty natural products discovered, including twenty night new compounds and three new derivatives. The research of soft coral Clavularia viridis has result in the isolation of six new prostanoids, designated as 4-deacetoxyl-12-O-deacetylclavulone I (1), 4-deacetoxyl-12-O-deacetylclavulone II (2), bromovulone II (3), iodovulone II (4), 4-deacetoxyl-12-O-deacetylclavuloneIII (5), and bromovulone III (6), together with seven known prostanoids, identified as clavulone I (33), clavulone II (34), chlorovulone II (35), 4-deacetoxylclavulone II (36), clavulone III (37), chlorovulone III (38), and 7-acetoxy-7,8-dihydroiodovulone I (39). In the investigation of the soft coral Xenia florida, three new compounds called florxenilides A-C (7-9), has been purified. The research also obtained seven xenicane-type diterpenes, xeniafaraunol A (40), xeniafaraunol B (41), florlide A (42), florlide C (43), florlide D (44), 9-deoxyxeniolide A (45), and 9-deoxyxeniolide B (46) in addition to two cadinene-type sesquiterpenes, xenitorins A (47) and B (48). Florxenilides A and C also treated with some chemical reagents to afford three new derivatives, 10-benzoylflorxenilide A (10), Florxenilide C monoacetate (11), and 10-dehydroflorxenilide A (12). Otherwise, the study in Cespitularia taeniata has afforded ten new nitrogen-containing compounds, cespitulactams D-K (13-20) and taenialactams A-B (21-22), in addition to four known compounds, atractylenolactam (49), cespitulactam A (50), cespitulactam B (51), and cespitularin F (52). Moreover, there were three new compounds, namely cespihypotins E, F, and H (23, 24, 25) have been discovered from another soft coral Cespitularia hypotentaculata. The study of this coral also observed seven known components called cespihypotin G (53), cespitulactone A (54), cespitularin F (52), cespitularin D (56), cespihypotins A-C (55, 57, 58). Investigation of the non-polar extract of the soft coral Sarcophyton stolidotum collected in Kenting resulted in the isolation of seven new 14-membered carbocyclic cembranes, sarcostolides A-G (26-32), together with two known cembranes isosarcophytoxide (59) and isosarcophine (60). All the structures of above metabolites were elucidated by physical and spectroscopic analyses including IR, Mass, UV, NMR, and optical rotation, and by compared with published data in many previous papers. The stereochemistry of these compounds as determined by NOESY experiments, CD spectroscopic data, and Mosher¡¦s methods. Cytotoxicity tests were measured by Dr. Kuo Yao-Haur and Dr. Guh Jih-Hwa. Isolated marine prostanoids showed potent activities against human prostate carcinoma (PC-3) and colon adenocarcinoma (HT-29) cells. Among them bromovulone III (6) had the most potent cytotoxicity against both cell lines at IC50 0.5

The prostaglandins comprise a group of bioactive lipids generated from arachidonic acid by cyclooxygenases and cell type-specific prostaglandin and thromboxane synthases. Prostaglandins mediate local cell signaling interactions by activation of G-protein coupled prostanoid receptors. Because the prostaglandins and their receptors are active in all tissues, they have an extraordinarily broad spectrum of physiological and pathophysiological functions that have hampered the development of safe prostanoid-based medications. This situation has emphasized the importance of understanding the functional properties of the prostanoid receptors and developing selective ligands capable of being used in patient care.The aims of this project were to identify novel regulatory functions of endogenous EP and FP prostanoid receptors in cultured human cells. Our results show that activation of EP₂ receptors in human microglia and astrocytes led to increased secretion of BDNF, a growth factor that regulates the survival of neurons. In the same cell lines, FP receptors regulate the induction of TNF-α gene expression through a classic G_q-PKC pathway. In microglia these FP receptors also stimulate a novel signaling crosstalk mechanism involving the up-regulation of TCF transcriptional function by Raf kinases, which culminates in the expression of the angiogenic inducer Cyr61. FP receptors also regulate the induction of angiogenic immediate early genes in cultured ciliary muscle cells, which may constitute the early steps in a mechanism by which commercial FP agonists reduce intraocular pressure in glaucoma therapy.The up-regulation of BDNF through glial EP₂ receptors constitutes a mechanism by which elevated PGE₂ in the inflamed brain might elicit either healing processes in the brain or neuronal apoptosis. On the other hand, induction of TNF-α and Cyr61 by glial FP receptors may mediate neuroinflammation and may also contribute to glioma tumor growth. Stimulation of FP receptors in the ciliary muscle leads to the induction of immediate early genes capable of coordinating tissue remodeling processes that have been previously documented. The results of these studies suggest novel regulatory functions of the prostanoid receptors in the brain and eye. Furthermore, these findings provide insight on how the selective modulation of the EP₂ and FP receptors might be therapeutically advantageous.

Transition of the cardiopulmonary circulation at birth requires functional closure of the ductus arteriosus (DA). The DA is an arterial shunt that is vital in the fetus for diverting the pulmonary circulation away from the uninflated lungs. Failure of the vessel to functionally close after birth is known as patent DA, which is the second most common congenital heart disease. Patent DA may seriously compromise neonatal health and current pharmacological treatments are often limited by serious complications or a significant failure rate, thereby increasing the necessity for surgical intervention. Recently, we were the first to show that genetic or pharmacological inactivation of cyclooxygenase (COX) -2 produces postnatal patent DA in mice. We also demonstrated that the DA expresses high levels of COX-2 during normal closure after birth, suggesting novel contractile actions of COX-2-dependent prostanoids in the DA. In humans, patent DA is more common in preterm infants than those born at full-term, however, mechanism(s) responsible for the reduced DA closure have not been identified. In the current studies, we examined COX-1 and COX-2 expression in the DA at multiple stages of gestation to determine whether alterations in the expression of these enzymes contribute to patent DA in preterm mice. Using real-time PCR, analysis of the time-course of COX-2 mRNA in the fetal mouse DA indicated that COX-2 expression significantly increased with advancing gestational age. The preterm (day 17.5) neonatal mouse DA showed attenuated COX-2 expression, as compared to the full-term (day 19.5) neonatal DA at 3 hours after birth. Furthermore, the DA of preterm neonatal mice showed incomplete closure after 3 hours of birth, a time-point when the DA of full-term neonates was completely remodeled. These data indicate a correlation between reduced DA closure and attenuated COX-2 expression. Additionally, COX-2 expression was significantly attenuated in the DA of mice deficient in the prostanoid receptor EP4, which also show a patent DA phenotype, suggesting the importance of this receptor for the induction of COX-2 required for DA closure. Overall, these studies suggest that attenuated expression of COX-2 may contribute to increased patent DA at preterm gestation.

O glioblastoma (GBM) é o tumor mais frequente do sistema nervoso central com um alto grau de malignidade e um prognóstico desfavorável. Apesar dos avanços nas técnicas cirúrgicas e de radioterapia e/ou quimioterapia, não há tratamento eficiente disponível para o GBM. Os prostanoide são derivados do ácido araquidônico e estão envolvidas com vários processos do desenvolvimento e progressão do câncer. O objetivo deste estudo foi analisar in vitro o perfil de diferentes prostanoides nas linhagens de GBM. Além de analisar o papel dos prostanoides e dos receptores na migração celular de GBM. Os resultados demostraram um perfil dos prostanoides da série 2 diferente entre as linhagens, além da expressão dos genes envolvidos na biossíntese de PGE2. Nos ensaios de migração os dados demostraram que os tratamentos realizados com os prostanoides exógenos aumentaram a migração celular e os tratamentos com os antagonistas de EP2 e EP4 diminuiram a migração. Em conjunto esses resultados, demonstram o papel importante dos prostanoides, especialmente PGE2, no processo de migração das células de GBM. / Glioblastoma (GBM) is the most common tumor of the central nervous system with a high degree of malignancy and poor prognosis. Despite advances in surgical techniques and radiation therapy and/or chemotherapy, there is no effective treatment available for GBM. The prostanoid are derived from arachidonic acid and are involved in many processes of development and progression of cancer. The aim of this study was to analyze in vitro profile of different prostanoids in the lines of GBM. In addition to analyzing the role of prostanoids and receptors on the cell migration of GBM. The results showed a profile of series 2 prostanoids the different between the cell lines, in addition to expression of genes involved in the biosynthesis of PGE2. In migration testing data showed that the treatments performed with exogenous prostanoids increased cell migration and treatment with antagonists of EP2 and EP4 decreased migration. Together these results demonstrate the important role of prostanoids, especially PGE2, in the migration process of the GBM cells.

O glioblastoma (GBM) é o tumor mais frequente do sistema nervoso central com um alto grau de malignidade e um prognóstico desfavorável. Apesar dos avanços nas técnicas cirúrgicas e de radioterapia e/ou quimioterapia, não há tratamento eficiente disponível para o GBM. Os prostanoide são derivados do ácido araquidônico e estão envolvidas com vários processos do desenvolvimento e progressão do câncer. O objetivo deste estudo foi analisar in vitro o perfil de diferentes prostanoides nas linhagens de GBM. Além de analisar o papel dos prostanoides e dos receptores na migração celular de GBM. Os resultados demostraram um perfil dos prostanoides da série 2 diferente entre as linhagens, além da expressão dos genes envolvidos na biossíntese de PGE2. Nos ensaios de migração os dados demostraram que os tratamentos realizados com os prostanoides exógenos aumentaram a migração celular e os tratamentos com os antagonistas de EP2 e EP4 diminuiram a migração. Em conjunto esses resultados, demonstram o papel importante dos prostanoides, especialmente PGE2, no processo de migração das células de GBM. / Glioblastoma (GBM) is the most common tumor of the central nervous system with a high degree of malignancy and poor prognosis. Despite advances in surgical techniques and radiation therapy and/or chemotherapy, there is no effective treatment available for GBM. The prostanoid are derived from arachidonic acid and are involved in many processes of development and progression of cancer. The aim of this study was to analyze in vitro profile of different prostanoids in the lines of GBM. In addition to analyzing the role of prostanoids and receptors on the cell migration of GBM. The results showed a profile of series 2 prostanoids the different between the cell lines, in addition to expression of genes involved in the biosynthesis of PGE2. In migration testing data showed that the treatments performed with exogenous prostanoids increased cell migration and treatment with antagonists of EP2 and EP4 decreased migration. Together these results demonstrate the important role of prostanoids, especially PGE2, in the migration process of the GBM cells.

Prostaglandins are integral mediators in reproductive processes but their exact role in uterine function is still not clear. In addition, ethical restraints have limited the availability of human tissue to investigate uterine prostanoid receptor populations. The aim of this thesis was to characterise the prostanoid receptors on the human and rat myometrium in order to evaluate the potential of the rat as an animal model of human uterine function and disease. For functional analysis of myometrial prostanoid receptors the immersion technique was utilised. LC-ESI-MS/MS was also used to measure the ex vivo myometrial release of prostanoid metabolites. The results show that both the rat and human uterus displays cyclical changes in uterine motility, with myogenicity greatest in the follicular and oestrus stages. The data also indicate that whilst the human uterus is responsive to EP3, EP2, TP, FP and IP receptor agonists, a functional population of only EP3, EP2 and FP receptors is present on the rat uterus, although the TP receptor appears to be upregulated at gestation and post-partum. The results also show that myometrial prostanoid release in the human uterus is cyclically regulated, with the greatest amount of prostaglandins being released during the late follicular stage. In conclusion, although similarities do exist with regard to the ovarian regulation of uterine motility in both the rat and human uterus, the differences in the apparent functional prostaglandin receptor populations between the two species suggest further work is required before the rat can be used as a model of human uterine function.

Colorectal cancer, among other tumors, is characterized by elevated levels of prostaglandins due to the up-regulation of cyclooxygenase -2 (COX-2), a key enzyme in the eicosanoid biosynthesis pathway. Prostaglandin E2 (PGE2) is an important prostaglandin that exerts its biological function via four transmembrane G protein coupled receptors (EP1-4), among which the EP4 receptor is the most important. The relevance of EP4 receptor to the carcinogenic process and the consequences of its interaction with PGE2 were explored in this dissertation.Despite the importance of the EP4 receptor in colon carcinogenesis, studies looking at the receptor expression during cancer progression have not been extensive. One study showed that the protein levels of EP4 receptor were elevated in colon cancer whereas another study indicated that mRNA levels were decreased in tumor compared to normal. We expanded these observations and now report that the elevated protein levels of EP4 receptor in cancer are due to increased translation of proteins.In addition, we identified S100P as a novel downstream target of the PGE2/EP4 receptor signaling pathway. S100P has been previously implicated in a number of gastro-intestinal cancers such as pancreatic, gastric and colon cancers. However, its regulation via the PGE2/EP4 receptor signaling pathway has never been investigated. Here, we show that PGE2 via the EP4 receptor signaling leads to the transcriptional activation of S100P and that this activation happens exclusively in the presence of CREB. In summary, this dissertation brings to light novel therapeutic targets which could be used as potential markers to stratify colon cancer patients as well as avenues for clinical intervention for the management of colon carcinogenesis.